Make `ChannelManager::issue_channel_close_events` take a `ChannelContext`
[rust-lightning] / lightning / src / ln / channel.rs
index b1cd603f021d61564af75f2aa8216452973feb0a..1e37335a86f6b48a30f8d5582b14d0ab4a6d3d28 100644 (file)
@@ -830,1460 +830,1502 @@ impl<Signer: ChannelSigner> ChannelContext<Signer> {
        pub fn is_live(&self) -> bool {
                self.is_usable() && (self.channel_state & (ChannelState::PeerDisconnected as u32) == 0)
        }
-}
 
-// Internal utility functions for channels
+       // Public utilities:
 
-/// Returns the value to use for `holder_max_htlc_value_in_flight_msat` as a percentage of the
-/// `channel_value_satoshis` in msat, set through
-/// [`ChannelHandshakeConfig::max_inbound_htlc_value_in_flight_percent_of_channel`]
-///
-/// The effective percentage is lower bounded by 1% and upper bounded by 100%.
-///
-/// [`ChannelHandshakeConfig::max_inbound_htlc_value_in_flight_percent_of_channel`]: crate::util::config::ChannelHandshakeConfig::max_inbound_htlc_value_in_flight_percent_of_channel
-fn get_holder_max_htlc_value_in_flight_msat(channel_value_satoshis: u64, config: &ChannelHandshakeConfig) -> u64 {
-       let configured_percent = if config.max_inbound_htlc_value_in_flight_percent_of_channel < 1 {
-               1
-       } else if config.max_inbound_htlc_value_in_flight_percent_of_channel > 100 {
-               100
-       } else {
-               config.max_inbound_htlc_value_in_flight_percent_of_channel as u64
-       };
-       channel_value_satoshis * 10 * configured_percent
-}
+       pub fn channel_id(&self) -> [u8; 32] {
+               self.channel_id
+       }
 
-/// Returns a minimum channel reserve value the remote needs to maintain,
-/// required by us according to the configured or default
-/// [`ChannelHandshakeConfig::their_channel_reserve_proportional_millionths`]
-///
-/// Guaranteed to return a value no larger than channel_value_satoshis
-///
-/// This is used both for outbound and inbound channels and has lower bound
-/// of `MIN_THEIR_CHAN_RESERVE_SATOSHIS`.
-pub(crate) fn get_holder_selected_channel_reserve_satoshis(channel_value_satoshis: u64, config: &UserConfig) -> u64 {
-       let calculated_reserve = channel_value_satoshis.saturating_mul(config.channel_handshake_config.their_channel_reserve_proportional_millionths as u64) / 1_000_000;
-       cmp::min(channel_value_satoshis, cmp::max(calculated_reserve, MIN_THEIR_CHAN_RESERVE_SATOSHIS))
-}
+       // Return the `temporary_channel_id` used during channel establishment.
+       //
+       // Will return `None` for channels created prior to LDK version 0.0.115.
+       pub fn temporary_channel_id(&self) -> Option<[u8; 32]> {
+               self.temporary_channel_id
+       }
 
-/// This is for legacy reasons, present for forward-compatibility.
-/// LDK versions older than 0.0.104 don't know how read/handle values other than default
-/// from storage. Hence, we use this function to not persist default values of
-/// `holder_selected_channel_reserve_satoshis` for channels into storage.
-pub(crate) fn get_legacy_default_holder_selected_channel_reserve_satoshis(channel_value_satoshis: u64) -> u64 {
-       let (q, _) = channel_value_satoshis.overflowing_div(100);
-       cmp::min(channel_value_satoshis, cmp::max(q, 1000))
-}
+       pub fn minimum_depth(&self) -> Option<u32> {
+               self.minimum_depth
+       }
 
-// TODO: We should refactor this to be an Inbound/OutboundChannel until initial setup handshaking
-// has been completed, and then turn into a Channel to get compiler-time enforcement of things like
-// calling channel_id() before we're set up or things like get_outbound_funding_signed on an
-// inbound channel.
-//
-// Holder designates channel data owned for the benefit of the user client.
-// Counterparty designates channel data owned by the another channel participant entity.
-pub(super) struct Channel<Signer: ChannelSigner> {
-       pub context: ChannelContext<Signer>,
-}
+       /// Gets the "user_id" value passed into the construction of this channel. It has no special
+       /// meaning and exists only to allow users to have a persistent identifier of a channel.
+       pub fn get_user_id(&self) -> u128 {
+               self.user_id
+       }
 
-#[cfg(any(test, fuzzing))]
-struct CommitmentTxInfoCached {
-       fee: u64,
-       total_pending_htlcs: usize,
-       next_holder_htlc_id: u64,
-       next_counterparty_htlc_id: u64,
-       feerate: u32,
-}
+       /// Gets the channel's type
+       pub fn get_channel_type(&self) -> &ChannelTypeFeatures {
+               &self.channel_type
+       }
 
-pub const DEFAULT_MAX_HTLCS: u16 = 50;
+       /// Guaranteed to be Some after both ChannelReady messages have been exchanged (and, thus,
+       /// is_usable() returns true).
+       /// Allowed in any state (including after shutdown)
+       pub fn get_short_channel_id(&self) -> Option<u64> {
+               self.short_channel_id
+       }
 
-pub(crate) fn commitment_tx_base_weight(opt_anchors: bool) -> u64 {
-       const COMMITMENT_TX_BASE_WEIGHT: u64 = 724;
-       const COMMITMENT_TX_BASE_ANCHOR_WEIGHT: u64 = 1124;
-       if opt_anchors { COMMITMENT_TX_BASE_ANCHOR_WEIGHT } else { COMMITMENT_TX_BASE_WEIGHT }
-}
+       /// Allowed in any state (including after shutdown)
+       pub fn latest_inbound_scid_alias(&self) -> Option<u64> {
+               self.latest_inbound_scid_alias
+       }
 
-#[cfg(not(test))]
-const COMMITMENT_TX_WEIGHT_PER_HTLC: u64 = 172;
-#[cfg(test)]
-pub const COMMITMENT_TX_WEIGHT_PER_HTLC: u64 = 172;
+       /// Allowed in any state (including after shutdown)
+       pub fn outbound_scid_alias(&self) -> u64 {
+               self.outbound_scid_alias
+       }
 
-pub const ANCHOR_OUTPUT_VALUE_SATOSHI: u64 = 330;
+       /// Only allowed immediately after deserialization if get_outbound_scid_alias returns 0,
+       /// indicating we were written by LDK prior to 0.0.106 which did not set outbound SCID aliases.
+       pub fn set_outbound_scid_alias(&mut self, outbound_scid_alias: u64) {
+               assert_eq!(self.outbound_scid_alias, 0);
+               self.outbound_scid_alias = outbound_scid_alias;
+       }
 
-/// The percentage of the channel value `holder_max_htlc_value_in_flight_msat` used to be set to,
-/// before this was made configurable. The percentage was made configurable in LDK 0.0.107,
-/// although LDK 0.0.104+ enabled serialization of channels with a different value set for
-/// `holder_max_htlc_value_in_flight_msat`.
-pub const MAX_IN_FLIGHT_PERCENT_LEGACY: u8 = 10;
+       /// Returns the funding_txo we either got from our peer, or were given by
+       /// get_outbound_funding_created.
+       pub fn get_funding_txo(&self) -> Option<OutPoint> {
+               self.channel_transaction_parameters.funding_outpoint
+       }
 
-/// Maximum `funding_satoshis` value according to the BOLT #2 specification, if
-/// `option_support_large_channel` (aka wumbo channels) is not supported.
-/// It's 2^24 - 1.
-pub const MAX_FUNDING_SATOSHIS_NO_WUMBO: u64 = (1 << 24) - 1;
+       /// Returns the block hash in which our funding transaction was confirmed.
+       pub fn get_funding_tx_confirmed_in(&self) -> Option<BlockHash> {
+               self.funding_tx_confirmed_in
+       }
 
-/// Total bitcoin supply in satoshis.
-pub const TOTAL_BITCOIN_SUPPLY_SATOSHIS: u64 = 21_000_000 * 1_0000_0000;
+       /// Returns the current number of confirmations on the funding transaction.
+       pub fn get_funding_tx_confirmations(&self, height: u32) -> u32 {
+               if self.funding_tx_confirmation_height == 0 {
+                       // We either haven't seen any confirmation yet, or observed a reorg.
+                       return 0;
+               }
 
-/// The maximum network dust limit for standard script formats. This currently represents the
-/// minimum output value for a P2SH output before Bitcoin Core 22 considers the entire
-/// transaction non-standard and thus refuses to relay it.
-/// We also use this as the maximum counterparty `dust_limit_satoshis` allowed, given many
-/// implementations use this value for their dust limit today.
-pub const MAX_STD_OUTPUT_DUST_LIMIT_SATOSHIS: u64 = 546;
+               height.checked_sub(self.funding_tx_confirmation_height).map_or(0, |c| c + 1)
+       }
 
-/// The maximum channel dust limit we will accept from our counterparty.
-pub const MAX_CHAN_DUST_LIMIT_SATOSHIS: u64 = MAX_STD_OUTPUT_DUST_LIMIT_SATOSHIS;
+       fn get_holder_selected_contest_delay(&self) -> u16 {
+               self.channel_transaction_parameters.holder_selected_contest_delay
+       }
 
-/// The dust limit is used for both the commitment transaction outputs as well as the closing
-/// transactions. For cooperative closing transactions, we require segwit outputs, though accept
-/// *any* segwit scripts, which are allowed to be up to 42 bytes in length.
-/// In order to avoid having to concern ourselves with standardness during the closing process, we
-/// simply require our counterparty to use a dust limit which will leave any segwit output
-/// standard.
-/// See <https://github.com/lightning/bolts/issues/905> for more details.
-pub const MIN_CHAN_DUST_LIMIT_SATOSHIS: u64 = 354;
+       fn get_holder_pubkeys(&self) -> &ChannelPublicKeys {
+               &self.channel_transaction_parameters.holder_pubkeys
+       }
 
-// Just a reasonable implementation-specific safe lower bound, higher than the dust limit.
-pub const MIN_THEIR_CHAN_RESERVE_SATOSHIS: u64 = 1000;
+       pub fn get_counterparty_selected_contest_delay(&self) -> Option<u16> {
+               self.channel_transaction_parameters.counterparty_parameters
+                       .as_ref().map(|params| params.selected_contest_delay)
+       }
 
-/// Used to return a simple Error back to ChannelManager. Will get converted to a
-/// msgs::ErrorAction::SendErrorMessage or msgs::ErrorAction::IgnoreError as appropriate with our
-/// channel_id in ChannelManager.
-pub(super) enum ChannelError {
-       Ignore(String),
-       Warn(String),
-       Close(String),
-}
+       fn get_counterparty_pubkeys(&self) -> &ChannelPublicKeys {
+               &self.channel_transaction_parameters.counterparty_parameters.as_ref().unwrap().pubkeys
+       }
 
-impl fmt::Debug for ChannelError {
-       fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-               match self {
-                       &ChannelError::Ignore(ref e) => write!(f, "Ignore : {}", e),
-                       &ChannelError::Warn(ref e) => write!(f, "Warn : {}", e),
-                       &ChannelError::Close(ref e) => write!(f, "Close : {}", e),
-               }
+       /// Allowed in any state (including after shutdown)
+       pub fn get_counterparty_node_id(&self) -> PublicKey {
+               self.counterparty_node_id
        }
-}
 
-macro_rules! secp_check {
-       ($res: expr, $err: expr) => {
-               match $res {
-                       Ok(thing) => thing,
-                       Err(_) => return Err(ChannelError::Close($err)),
-               }
-       };
-}
+       /// Allowed in any state (including after shutdown)
+       pub fn get_holder_htlc_minimum_msat(&self) -> u64 {
+               self.holder_htlc_minimum_msat
+       }
 
-impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
-       fn get_initial_channel_type(config: &UserConfig, their_features: &InitFeatures) -> ChannelTypeFeatures {
-               // The default channel type (ie the first one we try) depends on whether the channel is
-               // public - if it is, we just go with `only_static_remotekey` as it's the only option
-               // available. If it's private, we first try `scid_privacy` as it provides better privacy
-               // with no other changes, and fall back to `only_static_remotekey`.
-               let mut ret = ChannelTypeFeatures::only_static_remote_key();
-               if !config.channel_handshake_config.announced_channel &&
-                       config.channel_handshake_config.negotiate_scid_privacy &&
-                       their_features.supports_scid_privacy() {
-                       ret.set_scid_privacy_required();
-               }
+       /// Allowed in any state (including after shutdown), but will return none before TheirInitSent
+       pub fn get_holder_htlc_maximum_msat(&self) -> Option<u64> {
+               self.get_htlc_maximum_msat(self.holder_max_htlc_value_in_flight_msat)
+       }
 
-               // Optionally, if the user would like to negotiate the `anchors_zero_fee_htlc_tx` option, we
-               // set it now. If they don't understand it, we'll fall back to our default of
-               // `only_static_remotekey`.
-               #[cfg(anchors)]
-               { // Attributes are not allowed on if expressions on our current MSRV of 1.41.
-                       if config.channel_handshake_config.negotiate_anchors_zero_fee_htlc_tx &&
-                               their_features.supports_anchors_zero_fee_htlc_tx() {
-                               ret.set_anchors_zero_fee_htlc_tx_required();
-                       }
-               }
+       /// Allowed in any state (including after shutdown)
+       pub fn get_announced_htlc_max_msat(&self) -> u64 {
+               return cmp::min(
+                       // Upper bound by capacity. We make it a bit less than full capacity to prevent attempts
+                       // to use full capacity. This is an effort to reduce routing failures, because in many cases
+                       // channel might have been used to route very small values (either by honest users or as DoS).
+                       self.channel_value_satoshis * 1000 * 9 / 10,
 
-               ret
+                       self.counterparty_max_htlc_value_in_flight_msat
+               );
        }
 
-       /// If we receive an error message, it may only be a rejection of the channel type we tried,
-       /// not of our ability to open any channel at all. Thus, on error, we should first call this
-       /// and see if we get a new `OpenChannel` message, otherwise the channel is failed.
-       pub(crate) fn maybe_handle_error_without_close(&mut self, chain_hash: BlockHash) -> Result<msgs::OpenChannel, ()> {
-               if !self.context.is_outbound() || self.context.channel_state != ChannelState::OurInitSent as u32 { return Err(()); }
-               if self.context.channel_type == ChannelTypeFeatures::only_static_remote_key() {
-                       // We've exhausted our options
-                       return Err(());
-               }
-               // We support opening a few different types of channels. Try removing our additional
-               // features one by one until we've either arrived at our default or the counterparty has
-               // accepted one.
-               //
-               // Due to the order below, we may not negotiate `option_anchors_zero_fee_htlc_tx` if the
-               // counterparty doesn't support `option_scid_privacy`. Since `get_initial_channel_type`
-               // checks whether the counterparty supports every feature, this would only happen if the
-               // counterparty is advertising the feature, but rejecting channels proposing the feature for
-               // whatever reason.
-               if self.context.channel_type.supports_anchors_zero_fee_htlc_tx() {
-                       self.context.channel_type.clear_anchors_zero_fee_htlc_tx();
-                       assert!(self.context.channel_transaction_parameters.opt_non_zero_fee_anchors.is_none());
-                       self.context.channel_transaction_parameters.opt_anchors = None;
-               } else if self.context.channel_type.supports_scid_privacy() {
-                       self.context.channel_type.clear_scid_privacy();
-               } else {
-                       self.context.channel_type = ChannelTypeFeatures::only_static_remote_key();
-               }
-               Ok(self.get_open_channel(chain_hash))
+       /// Allowed in any state (including after shutdown)
+       pub fn get_counterparty_htlc_minimum_msat(&self) -> u64 {
+               self.counterparty_htlc_minimum_msat
        }
 
-       // Constructors:
-       pub fn new_outbound<ES: Deref, SP: Deref, F: Deref>(
-               fee_estimator: &LowerBoundedFeeEstimator<F>, entropy_source: &ES, signer_provider: &SP, counterparty_node_id: PublicKey, their_features: &InitFeatures,
-               channel_value_satoshis: u64, push_msat: u64, user_id: u128, config: &UserConfig, current_chain_height: u32,
-               outbound_scid_alias: u64
-       ) -> Result<Channel<Signer>, APIError>
-       where ES::Target: EntropySource,
-             SP::Target: SignerProvider<Signer = Signer>,
-             F::Target: FeeEstimator,
-       {
-               let holder_selected_contest_delay = config.channel_handshake_config.our_to_self_delay;
-               let channel_keys_id = signer_provider.generate_channel_keys_id(false, channel_value_satoshis, user_id);
-               let holder_signer = signer_provider.derive_channel_signer(channel_value_satoshis, channel_keys_id);
-               let pubkeys = holder_signer.pubkeys().clone();
+       /// Allowed in any state (including after shutdown), but will return none before TheirInitSent
+       pub fn get_counterparty_htlc_maximum_msat(&self) -> Option<u64> {
+               self.get_htlc_maximum_msat(self.counterparty_max_htlc_value_in_flight_msat)
+       }
 
-               if !their_features.supports_wumbo() && channel_value_satoshis > MAX_FUNDING_SATOSHIS_NO_WUMBO {
-                       return Err(APIError::APIMisuseError{err: format!("funding_value must not exceed {}, it was {}", MAX_FUNDING_SATOSHIS_NO_WUMBO, channel_value_satoshis)});
-               }
-               if channel_value_satoshis >= TOTAL_BITCOIN_SUPPLY_SATOSHIS {
-                       return Err(APIError::APIMisuseError{err: format!("funding_value must be smaller than the total bitcoin supply, it was {}", channel_value_satoshis)});
-               }
-               let channel_value_msat = channel_value_satoshis * 1000;
-               if push_msat > channel_value_msat {
-                       return Err(APIError::APIMisuseError { err: format!("Push value ({}) was larger than channel_value ({})", push_msat, channel_value_msat) });
-               }
-               if holder_selected_contest_delay < BREAKDOWN_TIMEOUT {
-                       return Err(APIError::APIMisuseError {err: format!("Configured with an unreasonable our_to_self_delay ({}) putting user funds at risks", holder_selected_contest_delay)});
-               }
-               let holder_selected_channel_reserve_satoshis = get_holder_selected_channel_reserve_satoshis(channel_value_satoshis, config);
-               if holder_selected_channel_reserve_satoshis < MIN_CHAN_DUST_LIMIT_SATOSHIS {
-                       // Protocol level safety check in place, although it should never happen because
-                       // of `MIN_THEIR_CHAN_RESERVE_SATOSHIS`
-                       return Err(APIError::APIMisuseError { err: format!("Holder selected channel  reserve below implemention limit dust_limit_satoshis {}", holder_selected_channel_reserve_satoshis) });
-               }
+       fn get_htlc_maximum_msat(&self, party_max_htlc_value_in_flight_msat: u64) -> Option<u64> {
+               self.counterparty_selected_channel_reserve_satoshis.map(|counterparty_reserve| {
+                       let holder_reserve = self.holder_selected_channel_reserve_satoshis;
+                       cmp::min(
+                               (self.channel_value_satoshis - counterparty_reserve - holder_reserve) * 1000,
+                               party_max_htlc_value_in_flight_msat
+                       )
+               })
+       }
 
-               let channel_type = Self::get_initial_channel_type(&config, their_features);
-               debug_assert!(channel_type.is_subset(&channelmanager::provided_channel_type_features(&config)));
+       pub fn get_value_satoshis(&self) -> u64 {
+               self.channel_value_satoshis
+       }
 
-               let feerate = fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::Normal);
+       pub fn get_fee_proportional_millionths(&self) -> u32 {
+               self.config.options.forwarding_fee_proportional_millionths
+       }
 
-               let value_to_self_msat = channel_value_satoshis * 1000 - push_msat;
-               let commitment_tx_fee = Self::commit_tx_fee_msat(feerate, MIN_AFFORDABLE_HTLC_COUNT, channel_type.requires_anchors_zero_fee_htlc_tx());
-               if value_to_self_msat < commitment_tx_fee {
-                       return Err(APIError::APIMisuseError{ err: format!("Funding amount ({}) can't even pay fee for initial commitment transaction fee of {}.", value_to_self_msat / 1000, commitment_tx_fee / 1000) });
-               }
+       pub fn get_cltv_expiry_delta(&self) -> u16 {
+               cmp::max(self.config.options.cltv_expiry_delta, MIN_CLTV_EXPIRY_DELTA)
+       }
 
-               let mut secp_ctx = Secp256k1::new();
-               secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
+       pub fn get_max_dust_htlc_exposure_msat(&self) -> u64 {
+               self.config.options.max_dust_htlc_exposure_msat
+       }
 
-               let shutdown_scriptpubkey = if config.channel_handshake_config.commit_upfront_shutdown_pubkey {
-                       match signer_provider.get_shutdown_scriptpubkey() {
-                               Ok(scriptpubkey) => Some(scriptpubkey),
-                               Err(_) => return Err(APIError::ChannelUnavailable { err: "Failed to get shutdown scriptpubkey".to_owned()}),
-                       }
-               } else { None };
+       /// Returns the previous [`ChannelConfig`] applied to this channel, if any.
+       pub fn prev_config(&self) -> Option<ChannelConfig> {
+               self.prev_config.map(|prev_config| prev_config.0)
+       }
 
-               if let Some(shutdown_scriptpubkey) = &shutdown_scriptpubkey {
-                       if !shutdown_scriptpubkey.is_compatible(&their_features) {
-                               return Err(APIError::IncompatibleShutdownScript { script: shutdown_scriptpubkey.clone() });
-                       }
-               }
+       // Checks whether we should emit a `ChannelPending` event.
+       pub(crate) fn should_emit_channel_pending_event(&mut self) -> bool {
+               self.is_funding_initiated() && !self.channel_pending_event_emitted
+       }
 
-               let destination_script = match signer_provider.get_destination_script() {
-                       Ok(script) => script,
-                       Err(_) => return Err(APIError::ChannelUnavailable { err: "Failed to get destination script".to_owned()}),
-               };
+       // Returns whether we already emitted a `ChannelPending` event.
+       pub(crate) fn channel_pending_event_emitted(&self) -> bool {
+               self.channel_pending_event_emitted
+       }
 
-               let temporary_channel_id = entropy_source.get_secure_random_bytes();
+       // Remembers that we already emitted a `ChannelPending` event.
+       pub(crate) fn set_channel_pending_event_emitted(&mut self) {
+               self.channel_pending_event_emitted = true;
+       }
 
-               Ok(Channel {
-                       context: ChannelContext {
-                               user_id,
+       // Checks whether we should emit a `ChannelReady` event.
+       pub(crate) fn should_emit_channel_ready_event(&mut self) -> bool {
+               self.is_usable() && !self.channel_ready_event_emitted
+       }
 
-                               config: LegacyChannelConfig {
-                                       options: config.channel_config.clone(),
-                                       announced_channel: config.channel_handshake_config.announced_channel,
-                                       commit_upfront_shutdown_pubkey: config.channel_handshake_config.commit_upfront_shutdown_pubkey,
-                               },
+       // Remembers that we already emitted a `ChannelReady` event.
+       pub(crate) fn set_channel_ready_event_emitted(&mut self) {
+               self.channel_ready_event_emitted = true;
+       }
 
-                               prev_config: None,
+       /// Tracks the number of ticks elapsed since the previous [`ChannelConfig`] was updated. Once
+       /// [`EXPIRE_PREV_CONFIG_TICKS`] is reached, the previous config is considered expired and will
+       /// no longer be considered when forwarding HTLCs.
+       pub fn maybe_expire_prev_config(&mut self) {
+               if self.prev_config.is_none() {
+                       return;
+               }
+               let prev_config = self.prev_config.as_mut().unwrap();
+               prev_config.1 += 1;
+               if prev_config.1 == EXPIRE_PREV_CONFIG_TICKS {
+                       self.prev_config = None;
+               }
+       }
 
-                               inbound_handshake_limits_override: Some(config.channel_handshake_limits.clone()),
+       /// Returns the current [`ChannelConfig`] applied to the channel.
+       pub fn config(&self) -> ChannelConfig {
+               self.config.options
+       }
 
-                               channel_id: temporary_channel_id,
-                               temporary_channel_id: Some(temporary_channel_id),
-                               channel_state: ChannelState::OurInitSent as u32,
-                               announcement_sigs_state: AnnouncementSigsState::NotSent,
-                               secp_ctx,
-                               channel_value_satoshis,
+       /// Updates the channel's config. A bool is returned indicating whether the config update
+       /// applied resulted in a new ChannelUpdate message.
+       pub fn update_config(&mut self, config: &ChannelConfig) -> bool {
+               let did_channel_update =
+                       self.config.options.forwarding_fee_proportional_millionths != config.forwarding_fee_proportional_millionths ||
+                       self.config.options.forwarding_fee_base_msat != config.forwarding_fee_base_msat ||
+                       self.config.options.cltv_expiry_delta != config.cltv_expiry_delta;
+               if did_channel_update {
+                       self.prev_config = Some((self.config.options, 0));
+                       // Update the counter, which backs the ChannelUpdate timestamp, to allow the relay
+                       // policy change to propagate throughout the network.
+                       self.update_time_counter += 1;
+               }
+               self.config.options = *config;
+               did_channel_update
+       }
 
-                               latest_monitor_update_id: 0,
+       /// Returns true if funding_created was sent/received.
+       pub fn is_funding_initiated(&self) -> bool {
+               self.channel_state >= ChannelState::FundingSent as u32
+       }
 
-                               holder_signer,
-                               shutdown_scriptpubkey,
-                               destination_script,
+       /// Transaction nomenclature is somewhat confusing here as there are many different cases - a
+       /// transaction is referred to as "a's transaction" implying that a will be able to broadcast
+       /// the transaction. Thus, b will generally be sending a signature over such a transaction to
+       /// a, and a can revoke the transaction by providing b the relevant per_commitment_secret. As
+       /// such, a transaction is generally the result of b increasing the amount paid to a (or adding
+       /// an HTLC to a).
+       /// @local is used only to convert relevant internal structures which refer to remote vs local
+       /// to decide value of outputs and direction of HTLCs.
+       /// @generated_by_local is used to determine *which* HTLCs to include - noting that the HTLC
+       /// state may indicate that one peer has informed the other that they'd like to add an HTLC but
+       /// have not yet committed it. Such HTLCs will only be included in transactions which are being
+       /// generated by the peer which proposed adding the HTLCs, and thus we need to understand both
+       /// which peer generated this transaction and "to whom" this transaction flows.
+       #[inline]
+       fn build_commitment_transaction<L: Deref>(&self, commitment_number: u64, keys: &TxCreationKeys, local: bool, generated_by_local: bool, logger: &L) -> CommitmentStats
+               where L::Target: Logger
+       {
+               let mut included_dust_htlcs: Vec<(HTLCOutputInCommitment, Option<&HTLCSource>)> = Vec::new();
+               let num_htlcs = self.pending_inbound_htlcs.len() + self.pending_outbound_htlcs.len();
+               let mut included_non_dust_htlcs: Vec<(HTLCOutputInCommitment, Option<&HTLCSource>)> = Vec::with_capacity(num_htlcs);
 
-                               cur_holder_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
-                               cur_counterparty_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
-                               value_to_self_msat,
+               let broadcaster_dust_limit_satoshis = if local { self.holder_dust_limit_satoshis } else { self.counterparty_dust_limit_satoshis };
+               let mut remote_htlc_total_msat = 0;
+               let mut local_htlc_total_msat = 0;
+               let mut value_to_self_msat_offset = 0;
 
-                               pending_inbound_htlcs: Vec::new(),
-                               pending_outbound_htlcs: Vec::new(),
-                               holding_cell_htlc_updates: Vec::new(),
-                               pending_update_fee: None,
-                               holding_cell_update_fee: None,
-                               next_holder_htlc_id: 0,
-                               next_counterparty_htlc_id: 0,
-                               update_time_counter: 1,
+               let mut feerate_per_kw = self.feerate_per_kw;
+               if let Some((feerate, update_state)) = self.pending_update_fee {
+                       if match update_state {
+                               // Note that these match the inclusion criteria when scanning
+                               // pending_inbound_htlcs below.
+                               FeeUpdateState::RemoteAnnounced => { debug_assert!(!self.is_outbound()); !generated_by_local },
+                               FeeUpdateState::AwaitingRemoteRevokeToAnnounce => { debug_assert!(!self.is_outbound()); !generated_by_local },
+                               FeeUpdateState::Outbound => { assert!(self.is_outbound());  generated_by_local },
+                       } {
+                               feerate_per_kw = feerate;
+                       }
+               }
 
-                               resend_order: RAACommitmentOrder::CommitmentFirst,
+               log_trace!(logger, "Building commitment transaction number {} (really {} xor {}) for channel {} for {}, generated by {} with fee {}...",
+                       commitment_number, (INITIAL_COMMITMENT_NUMBER - commitment_number),
+                       get_commitment_transaction_number_obscure_factor(&self.get_holder_pubkeys().payment_point, &self.get_counterparty_pubkeys().payment_point, self.is_outbound()),
+                       log_bytes!(self.channel_id), if local { "us" } else { "remote" }, if generated_by_local { "us" } else { "remote" }, feerate_per_kw);
 
-                               monitor_pending_channel_ready: false,
-                               monitor_pending_revoke_and_ack: false,
-                               monitor_pending_commitment_signed: false,
-                               monitor_pending_forwards: Vec::new(),
-                               monitor_pending_failures: Vec::new(),
-                               monitor_pending_finalized_fulfills: Vec::new(),
+               macro_rules! get_htlc_in_commitment {
+                       ($htlc: expr, $offered: expr) => {
+                               HTLCOutputInCommitment {
+                                       offered: $offered,
+                                       amount_msat: $htlc.amount_msat,
+                                       cltv_expiry: $htlc.cltv_expiry,
+                                       payment_hash: $htlc.payment_hash,
+                                       transaction_output_index: None
+                               }
+                       }
+               }
 
-                               #[cfg(debug_assertions)]
-                               holder_max_commitment_tx_output: Mutex::new((channel_value_satoshis * 1000 - push_msat, push_msat)),
-                               #[cfg(debug_assertions)]
-                               counterparty_max_commitment_tx_output: Mutex::new((channel_value_satoshis * 1000 - push_msat, push_msat)),
+               macro_rules! add_htlc_output {
+                       ($htlc: expr, $outbound: expr, $source: expr, $state_name: expr) => {
+                               if $outbound == local { // "offered HTLC output"
+                                       let htlc_in_tx = get_htlc_in_commitment!($htlc, true);
+                                       let htlc_tx_fee = if self.opt_anchors() {
+                                               0
+                                       } else {
+                                               feerate_per_kw as u64 * htlc_timeout_tx_weight(false) / 1000
+                                       };
+                                       if $htlc.amount_msat / 1000 >= broadcaster_dust_limit_satoshis + htlc_tx_fee {
+                                               log_trace!(logger, "   ...including {} {} HTLC {} (hash {}) with value {}", if $outbound { "outbound" } else { "inbound" }, $state_name, $htlc.htlc_id, log_bytes!($htlc.payment_hash.0), $htlc.amount_msat);
+                                               included_non_dust_htlcs.push((htlc_in_tx, $source));
+                                       } else {
+                                               log_trace!(logger, "   ...including {} {} dust HTLC {} (hash {}) with value {} due to dust limit", if $outbound { "outbound" } else { "inbound" }, $state_name, $htlc.htlc_id, log_bytes!($htlc.payment_hash.0), $htlc.amount_msat);
+                                               included_dust_htlcs.push((htlc_in_tx, $source));
+                                       }
+                               } else {
+                                       let htlc_in_tx = get_htlc_in_commitment!($htlc, false);
+                                       let htlc_tx_fee = if self.opt_anchors() {
+                                               0
+                                       } else {
+                                               feerate_per_kw as u64 * htlc_success_tx_weight(false) / 1000
+                                       };
+                                       if $htlc.amount_msat / 1000 >= broadcaster_dust_limit_satoshis + htlc_tx_fee {
+                                               log_trace!(logger, "   ...including {} {} HTLC {} (hash {}) with value {}", if $outbound { "outbound" } else { "inbound" }, $state_name, $htlc.htlc_id, log_bytes!($htlc.payment_hash.0), $htlc.amount_msat);
+                                               included_non_dust_htlcs.push((htlc_in_tx, $source));
+                                       } else {
+                                               log_trace!(logger, "   ...including {} {} dust HTLC {} (hash {}) with value {}", if $outbound { "outbound" } else { "inbound" }, $state_name, $htlc.htlc_id, log_bytes!($htlc.payment_hash.0), $htlc.amount_msat);
+                                               included_dust_htlcs.push((htlc_in_tx, $source));
+                                       }
+                               }
+                       }
+               }
 
-                               last_sent_closing_fee: None,
-                               pending_counterparty_closing_signed: None,
-                               closing_fee_limits: None,
-                               target_closing_feerate_sats_per_kw: None,
+               for ref htlc in self.pending_inbound_htlcs.iter() {
+                       let (include, state_name) = match htlc.state {
+                               InboundHTLCState::RemoteAnnounced(_) => (!generated_by_local, "RemoteAnnounced"),
+                               InboundHTLCState::AwaitingRemoteRevokeToAnnounce(_) => (!generated_by_local, "AwaitingRemoteRevokeToAnnounce"),
+                               InboundHTLCState::AwaitingAnnouncedRemoteRevoke(_) => (true, "AwaitingAnnouncedRemoteRevoke"),
+                               InboundHTLCState::Committed => (true, "Committed"),
+                               InboundHTLCState::LocalRemoved(_) => (!generated_by_local, "LocalRemoved"),
+                       };
 
-                               inbound_awaiting_accept: false,
+                       if include {
+                               add_htlc_output!(htlc, false, None, state_name);
+                               remote_htlc_total_msat += htlc.amount_msat;
+                       } else {
+                               log_trace!(logger, "   ...not including inbound HTLC {} (hash {}) with value {} due to state ({})", htlc.htlc_id, log_bytes!(htlc.payment_hash.0), htlc.amount_msat, state_name);
+                               match &htlc.state {
+                                       &InboundHTLCState::LocalRemoved(ref reason) => {
+                                               if generated_by_local {
+                                                       if let &InboundHTLCRemovalReason::Fulfill(_) = reason {
+                                                               value_to_self_msat_offset += htlc.amount_msat as i64;
+                                                       }
+                                               }
+                                       },
+                                       _ => {},
+                               }
+                       }
+               }
 
-                               funding_tx_confirmed_in: None,
-                               funding_tx_confirmation_height: 0,
-                               short_channel_id: None,
-                               channel_creation_height: current_chain_height,
+               let mut preimages: Vec<PaymentPreimage> = Vec::new();
 
-                               feerate_per_kw: feerate,
-                               counterparty_dust_limit_satoshis: 0,
-                               holder_dust_limit_satoshis: MIN_CHAN_DUST_LIMIT_SATOSHIS,
-                               counterparty_max_htlc_value_in_flight_msat: 0,
-                               holder_max_htlc_value_in_flight_msat: get_holder_max_htlc_value_in_flight_msat(channel_value_satoshis, &config.channel_handshake_config),
-                               counterparty_selected_channel_reserve_satoshis: None, // Filled in in accept_channel
-                               holder_selected_channel_reserve_satoshis,
-                               counterparty_htlc_minimum_msat: 0,
-                               holder_htlc_minimum_msat: if config.channel_handshake_config.our_htlc_minimum_msat == 0 { 1 } else { config.channel_handshake_config.our_htlc_minimum_msat },
-                               counterparty_max_accepted_htlcs: 0,
-                               holder_max_accepted_htlcs: cmp::min(config.channel_handshake_config.our_max_accepted_htlcs, MAX_HTLCS),
-                               minimum_depth: None, // Filled in in accept_channel
+               for ref htlc in self.pending_outbound_htlcs.iter() {
+                       let (include, state_name) = match htlc.state {
+                               OutboundHTLCState::LocalAnnounced(_) => (generated_by_local, "LocalAnnounced"),
+                               OutboundHTLCState::Committed => (true, "Committed"),
+                               OutboundHTLCState::RemoteRemoved(_) => (generated_by_local, "RemoteRemoved"),
+                               OutboundHTLCState::AwaitingRemoteRevokeToRemove(_) => (generated_by_local, "AwaitingRemoteRevokeToRemove"),
+                               OutboundHTLCState::AwaitingRemovedRemoteRevoke(_) => (false, "AwaitingRemovedRemoteRevoke"),
+                       };
 
-                               counterparty_forwarding_info: None,
+                       let preimage_opt = match htlc.state {
+                               OutboundHTLCState::RemoteRemoved(OutboundHTLCOutcome::Success(p)) => p,
+                               OutboundHTLCState::AwaitingRemoteRevokeToRemove(OutboundHTLCOutcome::Success(p)) => p,
+                               OutboundHTLCState::AwaitingRemovedRemoteRevoke(OutboundHTLCOutcome::Success(p)) => p,
+                               _ => None,
+                       };
 
-                               channel_transaction_parameters: ChannelTransactionParameters {
-                                       holder_pubkeys: pubkeys,
-                                       holder_selected_contest_delay: config.channel_handshake_config.our_to_self_delay,
-                                       is_outbound_from_holder: true,
-                                       counterparty_parameters: None,
-                                       funding_outpoint: None,
-                                       opt_anchors: if channel_type.requires_anchors_zero_fee_htlc_tx() { Some(()) } else { None },
-                                       opt_non_zero_fee_anchors: None
-                               },
-                               funding_transaction: None,
+                       if let Some(preimage) = preimage_opt {
+                               preimages.push(preimage);
+                       }
 
-                               counterparty_cur_commitment_point: None,
-                               counterparty_prev_commitment_point: None,
-                               counterparty_node_id,
+                       if include {
+                               add_htlc_output!(htlc, true, Some(&htlc.source), state_name);
+                               local_htlc_total_msat += htlc.amount_msat;
+                       } else {
+                               log_trace!(logger, "   ...not including outbound HTLC {} (hash {}) with value {} due to state ({})", htlc.htlc_id, log_bytes!(htlc.payment_hash.0), htlc.amount_msat, state_name);
+                               match htlc.state {
+                                       OutboundHTLCState::AwaitingRemoteRevokeToRemove(OutboundHTLCOutcome::Success(_))|OutboundHTLCState::AwaitingRemovedRemoteRevoke(OutboundHTLCOutcome::Success(_)) => {
+                                               value_to_self_msat_offset -= htlc.amount_msat as i64;
+                                       },
+                                       OutboundHTLCState::RemoteRemoved(OutboundHTLCOutcome::Success(_)) => {
+                                               if !generated_by_local {
+                                                       value_to_self_msat_offset -= htlc.amount_msat as i64;
+                                               }
+                                       },
+                                       _ => {},
+                               }
+                       }
+               }
 
-                               counterparty_shutdown_scriptpubkey: None,
+               let mut value_to_self_msat: i64 = (self.value_to_self_msat - local_htlc_total_msat) as i64 + value_to_self_msat_offset;
+               assert!(value_to_self_msat >= 0);
+               // Note that in case they have several just-awaiting-last-RAA fulfills in-progress (ie
+               // AwaitingRemoteRevokeToRemove or AwaitingRemovedRemoteRevoke) we may have allowed them to
+               // "violate" their reserve value by couting those against it. Thus, we have to convert
+               // everything to i64 before subtracting as otherwise we can overflow.
+               let mut value_to_remote_msat: i64 = (self.channel_value_satoshis * 1000) as i64 - (self.value_to_self_msat as i64) - (remote_htlc_total_msat as i64) - value_to_self_msat_offset;
+               assert!(value_to_remote_msat >= 0);
 
-                               commitment_secrets: CounterpartyCommitmentSecrets::new(),
+               #[cfg(debug_assertions)]
+               {
+                       // Make sure that the to_self/to_remote is always either past the appropriate
+                       // channel_reserve *or* it is making progress towards it.
+                       let mut broadcaster_max_commitment_tx_output = if generated_by_local {
+                               self.holder_max_commitment_tx_output.lock().unwrap()
+                       } else {
+                               self.counterparty_max_commitment_tx_output.lock().unwrap()
+                       };
+                       debug_assert!(broadcaster_max_commitment_tx_output.0 <= value_to_self_msat as u64 || value_to_self_msat / 1000 >= self.counterparty_selected_channel_reserve_satoshis.unwrap() as i64);
+                       broadcaster_max_commitment_tx_output.0 = cmp::max(broadcaster_max_commitment_tx_output.0, value_to_self_msat as u64);
+                       debug_assert!(broadcaster_max_commitment_tx_output.1 <= value_to_remote_msat as u64 || value_to_remote_msat / 1000 >= self.holder_selected_channel_reserve_satoshis as i64);
+                       broadcaster_max_commitment_tx_output.1 = cmp::max(broadcaster_max_commitment_tx_output.1, value_to_remote_msat as u64);
+               }
 
-                               channel_update_status: ChannelUpdateStatus::Enabled,
-                               closing_signed_in_flight: false,
+               let total_fee_sat = commit_tx_fee_sat(feerate_per_kw, included_non_dust_htlcs.len(), self.channel_transaction_parameters.opt_anchors.is_some());
+               let anchors_val = if self.channel_transaction_parameters.opt_anchors.is_some() { ANCHOR_OUTPUT_VALUE_SATOSHI * 2 } else { 0 } as i64;
+               let (value_to_self, value_to_remote) = if self.is_outbound() {
+                       (value_to_self_msat / 1000 - anchors_val - total_fee_sat as i64, value_to_remote_msat / 1000)
+               } else {
+                       (value_to_self_msat / 1000, value_to_remote_msat / 1000 - anchors_val - total_fee_sat as i64)
+               };
 
-                               announcement_sigs: None,
+               let mut value_to_a = if local { value_to_self } else { value_to_remote };
+               let mut value_to_b = if local { value_to_remote } else { value_to_self };
+               let (funding_pubkey_a, funding_pubkey_b) = if local {
+                       (self.get_holder_pubkeys().funding_pubkey, self.get_counterparty_pubkeys().funding_pubkey)
+               } else {
+                       (self.get_counterparty_pubkeys().funding_pubkey, self.get_holder_pubkeys().funding_pubkey)
+               };
 
-                               #[cfg(any(test, fuzzing))]
-                               next_local_commitment_tx_fee_info_cached: Mutex::new(None),
-                               #[cfg(any(test, fuzzing))]
-                               next_remote_commitment_tx_fee_info_cached: Mutex::new(None),
+               if value_to_a >= (broadcaster_dust_limit_satoshis as i64) {
+                       log_trace!(logger, "   ...including {} output with value {}", if local { "to_local" } else { "to_remote" }, value_to_a);
+               } else {
+                       value_to_a = 0;
+               }
 
-                               workaround_lnd_bug_4006: None,
-                               sent_message_awaiting_response: None,
+               if value_to_b >= (broadcaster_dust_limit_satoshis as i64) {
+                       log_trace!(logger, "   ...including {} output with value {}", if local { "to_remote" } else { "to_local" }, value_to_b);
+               } else {
+                       value_to_b = 0;
+               }
 
-                               latest_inbound_scid_alias: None,
-                               outbound_scid_alias,
+               let num_nondust_htlcs = included_non_dust_htlcs.len();
 
-                               channel_pending_event_emitted: false,
-                               channel_ready_event_emitted: false,
+               let channel_parameters =
+                       if local { self.channel_transaction_parameters.as_holder_broadcastable() }
+                       else { self.channel_transaction_parameters.as_counterparty_broadcastable() };
+               let tx = CommitmentTransaction::new_with_auxiliary_htlc_data(commitment_number,
+                                                                            value_to_a as u64,
+                                                                            value_to_b as u64,
+                                                                            self.channel_transaction_parameters.opt_anchors.is_some(),
+                                                                            funding_pubkey_a,
+                                                                            funding_pubkey_b,
+                                                                            keys.clone(),
+                                                                            feerate_per_kw,
+                                                                            &mut included_non_dust_htlcs,
+                                                                            &channel_parameters
+               );
+               let mut htlcs_included = included_non_dust_htlcs;
+               // The unwrap is safe, because all non-dust HTLCs have been assigned an output index
+               htlcs_included.sort_unstable_by_key(|h| h.0.transaction_output_index.unwrap());
+               htlcs_included.append(&mut included_dust_htlcs);
 
-                               #[cfg(any(test, fuzzing))]
-                               historical_inbound_htlc_fulfills: HashSet::new(),
+               // For the stats, trimmed-to-0 the value in msats accordingly
+               value_to_self_msat = if (value_to_self_msat * 1000) < broadcaster_dust_limit_satoshis as i64 { 0 } else { value_to_self_msat };
+               value_to_remote_msat = if (value_to_remote_msat * 1000) < broadcaster_dust_limit_satoshis as i64 { 0 } else { value_to_remote_msat };
 
-                               channel_type,
-                               channel_keys_id,
+               CommitmentStats {
+                       tx,
+                       feerate_per_kw,
+                       total_fee_sat,
+                       num_nondust_htlcs,
+                       htlcs_included,
+                       local_balance_msat: value_to_self_msat as u64,
+                       remote_balance_msat: value_to_remote_msat as u64,
+                       preimages
+               }
+       }
 
-                               pending_monitor_updates: Vec::new(),
-                       }
-               })
+       #[inline]
+       /// Creates a set of keys for build_commitment_transaction to generate a transaction which our
+       /// counterparty will sign (ie DO NOT send signatures over a transaction created by this to
+       /// our counterparty!)
+       /// The result is a transaction which we can revoke broadcastership of (ie a "local" transaction)
+       /// TODO Some magic rust shit to compile-time check this?
+       fn build_holder_transaction_keys(&self, commitment_number: u64) -> TxCreationKeys {
+               let per_commitment_point = self.holder_signer.get_per_commitment_point(commitment_number, &self.secp_ctx);
+               let delayed_payment_base = &self.get_holder_pubkeys().delayed_payment_basepoint;
+               let htlc_basepoint = &self.get_holder_pubkeys().htlc_basepoint;
+               let counterparty_pubkeys = self.get_counterparty_pubkeys();
+
+               TxCreationKeys::derive_new(&self.secp_ctx, &per_commitment_point, delayed_payment_base, htlc_basepoint, &counterparty_pubkeys.revocation_basepoint, &counterparty_pubkeys.htlc_basepoint)
        }
 
-       fn check_remote_fee<F: Deref, L: Deref>(fee_estimator: &LowerBoundedFeeEstimator<F>,
-               feerate_per_kw: u32, cur_feerate_per_kw: Option<u32>, logger: &L)
-               -> Result<(), ChannelError> where F::Target: FeeEstimator, L::Target: Logger,
-       {
-               // We only bound the fee updates on the upper side to prevent completely absurd feerates,
-               // always accepting up to 25 sat/vByte or 10x our fee estimator's "High Priority" fee.
-               // We generally don't care too much if they set the feerate to something very high, but it
-               // could result in the channel being useless due to everything being dust.
-               let upper_limit = cmp::max(250 * 25,
-                       fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::HighPriority) as u64 * 10);
-               if feerate_per_kw as u64 > upper_limit {
-                       return Err(ChannelError::Close(format!("Peer's feerate much too high. Actual: {}. Our expected upper limit: {}", feerate_per_kw, upper_limit)));
-               }
-               let lower_limit = fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::Background);
-               // Some fee estimators round up to the next full sat/vbyte (ie 250 sats per kw), causing
-               // occasional issues with feerate disagreements between an initiator that wants a feerate
-               // of 1.1 sat/vbyte and a receiver that wants 1.1 rounded up to 2. Thus, we always add 250
-               // sat/kw before the comparison here.
-               if feerate_per_kw + 250 < lower_limit {
-                       if let Some(cur_feerate) = cur_feerate_per_kw {
-                               if feerate_per_kw > cur_feerate {
-                                       log_warn!(logger,
-                                               "Accepting feerate that may prevent us from closing this channel because it's higher than what we have now. Had {} s/kW, now {} s/kW.",
-                                               cur_feerate, feerate_per_kw);
-                                       return Ok(());
-                               }
-                       }
-                       return Err(ChannelError::Close(format!("Peer's feerate much too low. Actual: {}. Our expected lower limit: {} (- 250)", feerate_per_kw, lower_limit)));
-               }
-               Ok(())
+       #[inline]
+       /// Creates a set of keys for build_commitment_transaction to generate a transaction which we
+       /// will sign and send to our counterparty.
+       /// If an Err is returned, it is a ChannelError::Close (for get_outbound_funding_created)
+       fn build_remote_transaction_keys(&self) -> TxCreationKeys {
+               //TODO: Ensure that the payment_key derived here ends up in the library users' wallet as we
+               //may see payments to it!
+               let revocation_basepoint = &self.get_holder_pubkeys().revocation_basepoint;
+               let htlc_basepoint = &self.get_holder_pubkeys().htlc_basepoint;
+               let counterparty_pubkeys = self.get_counterparty_pubkeys();
+
+               TxCreationKeys::derive_new(&self.secp_ctx, &self.counterparty_cur_commitment_point.unwrap(), &counterparty_pubkeys.delayed_payment_basepoint, &counterparty_pubkeys.htlc_basepoint, revocation_basepoint, htlc_basepoint)
        }
 
-       /// Creates a new channel from a remote sides' request for one.
-       /// Assumes chain_hash has already been checked and corresponds with what we expect!
-       pub fn new_from_req<ES: Deref, SP: Deref, F: Deref, L: Deref>(
-               fee_estimator: &LowerBoundedFeeEstimator<F>, entropy_source: &ES, signer_provider: &SP,
-               counterparty_node_id: PublicKey, our_supported_features: &ChannelTypeFeatures,
-               their_features: &InitFeatures, msg: &msgs::OpenChannel, user_id: u128, config: &UserConfig,
-               current_chain_height: u32, logger: &L, outbound_scid_alias: u64
-       ) -> Result<Channel<Signer>, ChannelError>
-               where ES::Target: EntropySource,
-                         SP::Target: SignerProvider<Signer = Signer>,
-                         F::Target: FeeEstimator,
-                         L::Target: Logger,
-       {
-               let announced_channel = if (msg.channel_flags & 1) == 1 { true } else { false };
+       /// Gets the redeemscript for the funding transaction output (ie the funding transaction output
+       /// pays to get_funding_redeemscript().to_v0_p2wsh()).
+       /// Panics if called before accept_channel/new_from_req
+       pub fn get_funding_redeemscript(&self) -> Script {
+               make_funding_redeemscript(&self.get_holder_pubkeys().funding_pubkey, self.counterparty_funding_pubkey())
+       }
 
-               // First check the channel type is known, failing before we do anything else if we don't
-               // support this channel type.
-               let channel_type = if let Some(channel_type) = &msg.channel_type {
-                       if channel_type.supports_any_optional_bits() {
-                               return Err(ChannelError::Close("Channel Type field contained optional bits - this is not allowed".to_owned()));
-                       }
+       fn counterparty_funding_pubkey(&self) -> &PublicKey {
+               &self.get_counterparty_pubkeys().funding_pubkey
+       }
 
-                       // We only support the channel types defined by the `ChannelManager` in
-                       // `provided_channel_type_features`. The channel type must always support
-                       // `static_remote_key`.
-                       if !channel_type.requires_static_remote_key() {
-                               return Err(ChannelError::Close("Channel Type was not understood - we require static remote key".to_owned()));
-                       }
-                       // Make sure we support all of the features behind the channel type.
-                       if !channel_type.is_subset(our_supported_features) {
-                               return Err(ChannelError::Close("Channel Type contains unsupported features".to_owned()));
-                       }
-                       if channel_type.requires_scid_privacy() && announced_channel {
-                               return Err(ChannelError::Close("SCID Alias/Privacy Channel Type cannot be set on a public channel".to_owned()));
-                       }
-                       channel_type.clone()
-               } else {
-                       let channel_type = ChannelTypeFeatures::from_init(&their_features);
-                       if channel_type != ChannelTypeFeatures::only_static_remote_key() {
-                               return Err(ChannelError::Close("Only static_remote_key is supported for non-negotiated channel types".to_owned()));
-                       }
-                       channel_type
-               };
-               let opt_anchors = channel_type.supports_anchors_zero_fee_htlc_tx();
+       pub fn get_feerate_sat_per_1000_weight(&self) -> u32 {
+               self.feerate_per_kw
+       }
 
-               let channel_keys_id = signer_provider.generate_channel_keys_id(true, msg.funding_satoshis, user_id);
-               let holder_signer = signer_provider.derive_channel_signer(msg.funding_satoshis, channel_keys_id);
-               let pubkeys = holder_signer.pubkeys().clone();
-               let counterparty_pubkeys = ChannelPublicKeys {
-                       funding_pubkey: msg.funding_pubkey,
-                       revocation_basepoint: msg.revocation_basepoint,
-                       payment_point: msg.payment_point,
-                       delayed_payment_basepoint: msg.delayed_payment_basepoint,
-                       htlc_basepoint: msg.htlc_basepoint
-               };
-
-               if config.channel_handshake_config.our_to_self_delay < BREAKDOWN_TIMEOUT {
-                       return Err(ChannelError::Close(format!("Configured with an unreasonable our_to_self_delay ({}) putting user funds at risks. It must be greater than {}", config.channel_handshake_config.our_to_self_delay, BREAKDOWN_TIMEOUT)));
-               }
-
-               // Check sanity of message fields:
-               if msg.funding_satoshis > config.channel_handshake_limits.max_funding_satoshis {
-                       return Err(ChannelError::Close(format!("Per our config, funding must be at most {}. It was {}", config.channel_handshake_limits.max_funding_satoshis, msg.funding_satoshis)));
-               }
-               if msg.funding_satoshis >= TOTAL_BITCOIN_SUPPLY_SATOSHIS {
-                       return Err(ChannelError::Close(format!("Funding must be smaller than the total bitcoin supply. It was {}", msg.funding_satoshis)));
-               }
-               if msg.channel_reserve_satoshis > msg.funding_satoshis {
-                       return Err(ChannelError::Close(format!("Bogus channel_reserve_satoshis ({}). Must be not greater than funding_satoshis: {}", msg.channel_reserve_satoshis, msg.funding_satoshis)));
-               }
-               let full_channel_value_msat = (msg.funding_satoshis - msg.channel_reserve_satoshis) * 1000;
-               if msg.push_msat > full_channel_value_msat {
-                       return Err(ChannelError::Close(format!("push_msat {} was larger than channel amount minus reserve ({})", msg.push_msat, full_channel_value_msat)));
-               }
-               if msg.dust_limit_satoshis > msg.funding_satoshis {
-                       return Err(ChannelError::Close(format!("dust_limit_satoshis {} was larger than funding_satoshis {}. Peer never wants payout outputs?", msg.dust_limit_satoshis, msg.funding_satoshis)));
-               }
-               if msg.htlc_minimum_msat >= full_channel_value_msat {
-                       return Err(ChannelError::Close(format!("Minimum htlc value ({}) was larger than full channel value ({})", msg.htlc_minimum_msat, full_channel_value_msat)));
-               }
-               Channel::<Signer>::check_remote_fee(fee_estimator, msg.feerate_per_kw, None, logger)?;
-
-               let max_counterparty_selected_contest_delay = u16::min(config.channel_handshake_limits.their_to_self_delay, MAX_LOCAL_BREAKDOWN_TIMEOUT);
-               if msg.to_self_delay > max_counterparty_selected_contest_delay {
-                       return Err(ChannelError::Close(format!("They wanted our payments to be delayed by a needlessly long period. Upper limit: {}. Actual: {}", max_counterparty_selected_contest_delay, msg.to_self_delay)));
-               }
-               if msg.max_accepted_htlcs < 1 {
-                       return Err(ChannelError::Close("0 max_accepted_htlcs makes for a useless channel".to_owned()));
+       pub fn get_dust_buffer_feerate(&self, outbound_feerate_update: Option<u32>) -> u32 {
+               // When calculating our exposure to dust HTLCs, we assume that the channel feerate
+               // may, at any point, increase by at least 10 sat/vB (i.e 2530 sat/kWU) or 25%,
+               // whichever is higher. This ensures that we aren't suddenly exposed to significantly
+               // more dust balance if the feerate increases when we have several HTLCs pending
+               // which are near the dust limit.
+               let mut feerate_per_kw = self.feerate_per_kw;
+               // If there's a pending update fee, use it to ensure we aren't under-estimating
+               // potential feerate updates coming soon.
+               if let Some((feerate, _)) = self.pending_update_fee {
+                       feerate_per_kw = cmp::max(feerate_per_kw, feerate);
                }
-               if msg.max_accepted_htlcs > MAX_HTLCS {
-                       return Err(ChannelError::Close(format!("max_accepted_htlcs was {}. It must not be larger than {}", msg.max_accepted_htlcs, MAX_HTLCS)));
+               if let Some(feerate) = outbound_feerate_update {
+                       feerate_per_kw = cmp::max(feerate_per_kw, feerate);
                }
+               cmp::max(2530, feerate_per_kw * 1250 / 1000)
+       }
 
-               // Now check against optional parameters as set by config...
-               if msg.funding_satoshis < config.channel_handshake_limits.min_funding_satoshis {
-                       return Err(ChannelError::Close(format!("Funding satoshis ({}) is less than the user specified limit ({})", msg.funding_satoshis, config.channel_handshake_limits.min_funding_satoshis)));
-               }
-               if msg.htlc_minimum_msat > config.channel_handshake_limits.max_htlc_minimum_msat {
-                       return Err(ChannelError::Close(format!("htlc_minimum_msat ({}) is higher than the user specified limit ({})", msg.htlc_minimum_msat,  config.channel_handshake_limits.max_htlc_minimum_msat)));
-               }
-               if msg.max_htlc_value_in_flight_msat < config.channel_handshake_limits.min_max_htlc_value_in_flight_msat {
-                       return Err(ChannelError::Close(format!("max_htlc_value_in_flight_msat ({}) is less than the user specified limit ({})", msg.max_htlc_value_in_flight_msat, config.channel_handshake_limits.min_max_htlc_value_in_flight_msat)));
-               }
-               if msg.channel_reserve_satoshis > config.channel_handshake_limits.max_channel_reserve_satoshis {
-                       return Err(ChannelError::Close(format!("channel_reserve_satoshis ({}) is higher than the user specified limit ({})", msg.channel_reserve_satoshis, config.channel_handshake_limits.max_channel_reserve_satoshis)));
-               }
-               if msg.max_accepted_htlcs < config.channel_handshake_limits.min_max_accepted_htlcs {
-                       return Err(ChannelError::Close(format!("max_accepted_htlcs ({}) is less than the user specified limit ({})", msg.max_accepted_htlcs, config.channel_handshake_limits.min_max_accepted_htlcs)));
-               }
-               if msg.dust_limit_satoshis < MIN_CHAN_DUST_LIMIT_SATOSHIS {
-                       return Err(ChannelError::Close(format!("dust_limit_satoshis ({}) is less than the implementation limit ({})", msg.dust_limit_satoshis, MIN_CHAN_DUST_LIMIT_SATOSHIS)));
-               }
-               if msg.dust_limit_satoshis >  MAX_CHAN_DUST_LIMIT_SATOSHIS {
-                       return Err(ChannelError::Close(format!("dust_limit_satoshis ({}) is greater than the implementation limit ({})", msg.dust_limit_satoshis, MAX_CHAN_DUST_LIMIT_SATOSHIS)));
-               }
+       /// Get forwarding information for the counterparty.
+       pub fn counterparty_forwarding_info(&self) -> Option<CounterpartyForwardingInfo> {
+               self.counterparty_forwarding_info.clone()
+       }
 
-               // Convert things into internal flags and prep our state:
+       /// Returns a HTLCStats about inbound pending htlcs
+       fn get_inbound_pending_htlc_stats(&self, outbound_feerate_update: Option<u32>) -> HTLCStats {
+               let context = self;
+               let mut stats = HTLCStats {
+                       pending_htlcs: context.pending_inbound_htlcs.len() as u32,
+                       pending_htlcs_value_msat: 0,
+                       on_counterparty_tx_dust_exposure_msat: 0,
+                       on_holder_tx_dust_exposure_msat: 0,
+                       holding_cell_msat: 0,
+                       on_holder_tx_holding_cell_htlcs_count: 0,
+               };
 
-               if config.channel_handshake_limits.force_announced_channel_preference {
-                       if config.channel_handshake_config.announced_channel != announced_channel {
-                               return Err(ChannelError::Close("Peer tried to open channel but their announcement preference is different from ours".to_owned()));
+               let (htlc_timeout_dust_limit, htlc_success_dust_limit) = if context.opt_anchors() {
+                       (0, 0)
+               } else {
+                       let dust_buffer_feerate = context.get_dust_buffer_feerate(outbound_feerate_update) as u64;
+                       (dust_buffer_feerate * htlc_timeout_tx_weight(false) / 1000,
+                               dust_buffer_feerate * htlc_success_tx_weight(false) / 1000)
+               };
+               let counterparty_dust_limit_timeout_sat = htlc_timeout_dust_limit + context.counterparty_dust_limit_satoshis;
+               let holder_dust_limit_success_sat = htlc_success_dust_limit + context.holder_dust_limit_satoshis;
+               for ref htlc in context.pending_inbound_htlcs.iter() {
+                       stats.pending_htlcs_value_msat += htlc.amount_msat;
+                       if htlc.amount_msat / 1000 < counterparty_dust_limit_timeout_sat {
+                               stats.on_counterparty_tx_dust_exposure_msat += htlc.amount_msat;
+                       }
+                       if htlc.amount_msat / 1000 < holder_dust_limit_success_sat {
+                               stats.on_holder_tx_dust_exposure_msat += htlc.amount_msat;
                        }
                }
+               stats
+       }
 
-               let holder_selected_channel_reserve_satoshis = get_holder_selected_channel_reserve_satoshis(msg.funding_satoshis, config);
-               if holder_selected_channel_reserve_satoshis < MIN_CHAN_DUST_LIMIT_SATOSHIS {
-                       // Protocol level safety check in place, although it should never happen because
-                       // of `MIN_THEIR_CHAN_RESERVE_SATOSHIS`
-                       return Err(ChannelError::Close(format!("Suitable channel reserve not found. remote_channel_reserve was ({}). dust_limit_satoshis is ({}).", holder_selected_channel_reserve_satoshis, MIN_CHAN_DUST_LIMIT_SATOSHIS)));
-               }
-               if holder_selected_channel_reserve_satoshis * 1000 >= full_channel_value_msat {
-                       return Err(ChannelError::Close(format!("Suitable channel reserve not found. remote_channel_reserve was ({})msats. Channel value is ({} - {})msats.", holder_selected_channel_reserve_satoshis * 1000, full_channel_value_msat, msg.push_msat)));
-               }
-               if msg.channel_reserve_satoshis < MIN_CHAN_DUST_LIMIT_SATOSHIS {
-                       log_debug!(logger, "channel_reserve_satoshis ({}) is smaller than our dust limit ({}). We can broadcast stale states without any risk, implying this channel is very insecure for our counterparty.",
-                               msg.channel_reserve_satoshis, MIN_CHAN_DUST_LIMIT_SATOSHIS);
-               }
-               if holder_selected_channel_reserve_satoshis < msg.dust_limit_satoshis {
-                       return Err(ChannelError::Close(format!("Dust limit ({}) too high for the channel reserve we require the remote to keep ({})", msg.dust_limit_satoshis, holder_selected_channel_reserve_satoshis)));
-               }
-
-               // check if the funder's amount for the initial commitment tx is sufficient
-               // for full fee payment plus a few HTLCs to ensure the channel will be useful.
-               let funders_amount_msat = msg.funding_satoshis * 1000 - msg.push_msat;
-               let commitment_tx_fee = Self::commit_tx_fee_msat(msg.feerate_per_kw, MIN_AFFORDABLE_HTLC_COUNT, opt_anchors) / 1000;
-               if funders_amount_msat / 1000 < commitment_tx_fee {
-                       return Err(ChannelError::Close(format!("Funding amount ({} sats) can't even pay fee for initial commitment transaction fee of {} sats.", funders_amount_msat / 1000, commitment_tx_fee)));
-               }
+       /// Returns a HTLCStats about pending outbound htlcs, *including* pending adds in our holding cell.
+       fn get_outbound_pending_htlc_stats(&self, outbound_feerate_update: Option<u32>) -> HTLCStats {
+               let context = self;
+               let mut stats = HTLCStats {
+                       pending_htlcs: context.pending_outbound_htlcs.len() as u32,
+                       pending_htlcs_value_msat: 0,
+                       on_counterparty_tx_dust_exposure_msat: 0,
+                       on_holder_tx_dust_exposure_msat: 0,
+                       holding_cell_msat: 0,
+                       on_holder_tx_holding_cell_htlcs_count: 0,
+               };
 
-               let to_remote_satoshis = funders_amount_msat / 1000 - commitment_tx_fee;
-               // While it's reasonable for us to not meet the channel reserve initially (if they don't
-               // want to push much to us), our counterparty should always have more than our reserve.
-               if to_remote_satoshis < holder_selected_channel_reserve_satoshis {
-                       return Err(ChannelError::Close("Insufficient funding amount for initial reserve".to_owned()));
+               let (htlc_timeout_dust_limit, htlc_success_dust_limit) = if context.opt_anchors() {
+                       (0, 0)
+               } else {
+                       let dust_buffer_feerate = context.get_dust_buffer_feerate(outbound_feerate_update) as u64;
+                       (dust_buffer_feerate * htlc_timeout_tx_weight(false) / 1000,
+                               dust_buffer_feerate * htlc_success_tx_weight(false) / 1000)
+               };
+               let counterparty_dust_limit_success_sat = htlc_success_dust_limit + context.counterparty_dust_limit_satoshis;
+               let holder_dust_limit_timeout_sat = htlc_timeout_dust_limit + context.holder_dust_limit_satoshis;
+               for ref htlc in context.pending_outbound_htlcs.iter() {
+                       stats.pending_htlcs_value_msat += htlc.amount_msat;
+                       if htlc.amount_msat / 1000 < counterparty_dust_limit_success_sat {
+                               stats.on_counterparty_tx_dust_exposure_msat += htlc.amount_msat;
+                       }
+                       if htlc.amount_msat / 1000 < holder_dust_limit_timeout_sat {
+                               stats.on_holder_tx_dust_exposure_msat += htlc.amount_msat;
+                       }
                }
 
-               let counterparty_shutdown_scriptpubkey = if their_features.supports_upfront_shutdown_script() {
-                       match &msg.shutdown_scriptpubkey {
-                               &Some(ref script) => {
-                                       // Peer is signaling upfront_shutdown and has opt-out with a 0-length script. We don't enforce anything
-                                       if script.len() == 0 {
-                                               None
-                                       } else {
-                                               if !script::is_bolt2_compliant(&script, their_features) {
-                                                       return Err(ChannelError::Close(format!("Peer is signaling upfront_shutdown but has provided an unacceptable scriptpubkey format: {}", script)))
-                                               }
-                                               Some(script.clone())
-                                       }
-                               },
-                               // Peer is signaling upfront shutdown but don't opt-out with correct mechanism (a.k.a 0-length script). Peer looks buggy, we fail the channel
-                               &None => {
-                                       return Err(ChannelError::Close("Peer is signaling upfront_shutdown but we don't get any script. Use 0-length script to opt-out".to_owned()));
+               for update in context.holding_cell_htlc_updates.iter() {
+                       if let &HTLCUpdateAwaitingACK::AddHTLC { ref amount_msat, .. } = update {
+                               stats.pending_htlcs += 1;
+                               stats.pending_htlcs_value_msat += amount_msat;
+                               stats.holding_cell_msat += amount_msat;
+                               if *amount_msat / 1000 < counterparty_dust_limit_success_sat {
+                                       stats.on_counterparty_tx_dust_exposure_msat += amount_msat;
+                               }
+                               if *amount_msat / 1000 < holder_dust_limit_timeout_sat {
+                                       stats.on_holder_tx_dust_exposure_msat += amount_msat;
+                               } else {
+                                       stats.on_holder_tx_holding_cell_htlcs_count += 1;
                                }
                        }
-               } else { None };
+               }
+               stats
+       }
 
-               let shutdown_scriptpubkey = if config.channel_handshake_config.commit_upfront_shutdown_pubkey {
-                       match signer_provider.get_shutdown_scriptpubkey() {
-                               Ok(scriptpubkey) => Some(scriptpubkey),
-                               Err(_) => return Err(ChannelError::Close("Failed to get upfront shutdown scriptpubkey".to_owned())),
-                       }
-               } else { None };
+       /// Get the available balances, see [`AvailableBalances`]'s fields for more info.
+       /// Doesn't bother handling the
+       /// if-we-removed-it-already-but-haven't-fully-resolved-they-can-still-send-an-inbound-HTLC
+       /// corner case properly.
+       pub fn get_available_balances(&self) -> AvailableBalances {
+               let context = &self;
+               // Note that we have to handle overflow due to the above case.
+               let inbound_stats = context.get_inbound_pending_htlc_stats(None);
+               let outbound_stats = context.get_outbound_pending_htlc_stats(None);
 
-               if let Some(shutdown_scriptpubkey) = &shutdown_scriptpubkey {
-                       if !shutdown_scriptpubkey.is_compatible(&their_features) {
-                               return Err(ChannelError::Close(format!("Provided a scriptpubkey format not accepted by peer: {}", shutdown_scriptpubkey)));
+               let mut balance_msat = context.value_to_self_msat;
+               for ref htlc in context.pending_inbound_htlcs.iter() {
+                       if let InboundHTLCState::LocalRemoved(InboundHTLCRemovalReason::Fulfill(_)) = htlc.state {
+                               balance_msat += htlc.amount_msat;
                        }
                }
+               balance_msat -= outbound_stats.pending_htlcs_value_msat;
 
-               let destination_script = match signer_provider.get_destination_script() {
-                       Ok(script) => script,
-                       Err(_) => return Err(ChannelError::Close("Failed to get destination script".to_owned())),
-               };
+               let outbound_capacity_msat = context.value_to_self_msat
+                               .saturating_sub(outbound_stats.pending_htlcs_value_msat)
+                               .saturating_sub(
+                                       context.counterparty_selected_channel_reserve_satoshis.unwrap_or(0) * 1000);
 
-               let mut secp_ctx = Secp256k1::new();
-               secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
+               let mut available_capacity_msat = outbound_capacity_msat;
 
-               let chan = Channel {
-                       context: ChannelContext {
-                               user_id,
+               if context.is_outbound() {
+                       // We should mind channel commit tx fee when computing how much of the available capacity
+                       // can be used in the next htlc. Mirrors the logic in send_htlc.
+                       //
+                       // The fee depends on whether the amount we will be sending is above dust or not,
+                       // and the answer will in turn change the amount itself â€” making it a circular
+                       // dependency.
+                       // This complicates the computation around dust-values, up to the one-htlc-value.
+                       let mut real_dust_limit_timeout_sat = context.holder_dust_limit_satoshis;
+                       if !context.opt_anchors() {
+                               real_dust_limit_timeout_sat += context.feerate_per_kw as u64 * htlc_timeout_tx_weight(false) / 1000;
+                       }
 
-                               config: LegacyChannelConfig {
-                                       options: config.channel_config.clone(),
-                                       announced_channel,
-                                       commit_upfront_shutdown_pubkey: config.channel_handshake_config.commit_upfront_shutdown_pubkey,
-                               },
+                       let htlc_above_dust = HTLCCandidate::new(real_dust_limit_timeout_sat * 1000, HTLCInitiator::LocalOffered);
+                       let max_reserved_commit_tx_fee_msat = FEE_SPIKE_BUFFER_FEE_INCREASE_MULTIPLE * context.next_local_commit_tx_fee_msat(htlc_above_dust, Some(()));
+                       let htlc_dust = HTLCCandidate::new(real_dust_limit_timeout_sat * 1000 - 1, HTLCInitiator::LocalOffered);
+                       let min_reserved_commit_tx_fee_msat = FEE_SPIKE_BUFFER_FEE_INCREASE_MULTIPLE * context.next_local_commit_tx_fee_msat(htlc_dust, Some(()));
 
-                               prev_config: None,
+                       // We will first subtract the fee as if we were above-dust. Then, if the resulting
+                       // value ends up being below dust, we have this fee available again. In that case,
+                       // match the value to right-below-dust.
+                       let mut capacity_minus_commitment_fee_msat: i64 = (available_capacity_msat as i64) - (max_reserved_commit_tx_fee_msat as i64);
+                       if capacity_minus_commitment_fee_msat < (real_dust_limit_timeout_sat as i64) * 1000 {
+                               let one_htlc_difference_msat = max_reserved_commit_tx_fee_msat - min_reserved_commit_tx_fee_msat;
+                               debug_assert!(one_htlc_difference_msat != 0);
+                               capacity_minus_commitment_fee_msat += one_htlc_difference_msat as i64;
+                               capacity_minus_commitment_fee_msat = cmp::min(real_dust_limit_timeout_sat as i64 * 1000 - 1, capacity_minus_commitment_fee_msat);
+                               available_capacity_msat = cmp::max(0, cmp::min(capacity_minus_commitment_fee_msat, available_capacity_msat as i64)) as u64;
+                       } else {
+                               available_capacity_msat = capacity_minus_commitment_fee_msat as u64;
+                       }
+               } else {
+                       // If the channel is inbound (i.e. counterparty pays the fee), we need to make sure
+                       // sending a new HTLC won't reduce their balance below our reserve threshold.
+                       let mut real_dust_limit_success_sat = context.counterparty_dust_limit_satoshis;
+                       if !context.opt_anchors() {
+                               real_dust_limit_success_sat += context.feerate_per_kw as u64 * htlc_success_tx_weight(false) / 1000;
+                       }
 
-                               inbound_handshake_limits_override: None,
+                       let htlc_above_dust = HTLCCandidate::new(real_dust_limit_success_sat * 1000, HTLCInitiator::LocalOffered);
+                       let max_reserved_commit_tx_fee_msat = context.next_remote_commit_tx_fee_msat(htlc_above_dust, None);
 
-                               temporary_channel_id: Some(msg.temporary_channel_id),
-                               channel_id: msg.temporary_channel_id,
-                               channel_state: (ChannelState::OurInitSent as u32) | (ChannelState::TheirInitSent as u32),
-                               announcement_sigs_state: AnnouncementSigsState::NotSent,
-                               secp_ctx,
-
-                               latest_monitor_update_id: 0,
-
-                               holder_signer,
-                               shutdown_scriptpubkey,
-                               destination_script,
-
-                               cur_holder_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
-                               cur_counterparty_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
-                               value_to_self_msat: msg.push_msat,
-
-                               pending_inbound_htlcs: Vec::new(),
-                               pending_outbound_htlcs: Vec::new(),
-                               holding_cell_htlc_updates: Vec::new(),
-                               pending_update_fee: None,
-                               holding_cell_update_fee: None,
-                               next_holder_htlc_id: 0,
-                               next_counterparty_htlc_id: 0,
-                               update_time_counter: 1,
-
-                               resend_order: RAACommitmentOrder::CommitmentFirst,
+                       let holder_selected_chan_reserve_msat = context.holder_selected_channel_reserve_satoshis * 1000;
+                       let remote_balance_msat = (context.channel_value_satoshis * 1000 - context.value_to_self_msat)
+                               .saturating_sub(inbound_stats.pending_htlcs_value_msat);
 
-                               monitor_pending_channel_ready: false,
-                               monitor_pending_revoke_and_ack: false,
-                               monitor_pending_commitment_signed: false,
-                               monitor_pending_forwards: Vec::new(),
-                               monitor_pending_failures: Vec::new(),
-                               monitor_pending_finalized_fulfills: Vec::new(),
+                       if remote_balance_msat < max_reserved_commit_tx_fee_msat + holder_selected_chan_reserve_msat {
+                               // If another HTLC's fee would reduce the remote's balance below the reserve limit
+                               // we've selected for them, we can only send dust HTLCs.
+                               available_capacity_msat = cmp::min(available_capacity_msat, real_dust_limit_success_sat * 1000 - 1);
+                       }
+               }
 
-                               #[cfg(debug_assertions)]
-                               holder_max_commitment_tx_output: Mutex::new((msg.push_msat, msg.funding_satoshis * 1000 - msg.push_msat)),
-                               #[cfg(debug_assertions)]
-                               counterparty_max_commitment_tx_output: Mutex::new((msg.push_msat, msg.funding_satoshis * 1000 - msg.push_msat)),
+               let mut next_outbound_htlc_minimum_msat = context.counterparty_htlc_minimum_msat;
 
-                               last_sent_closing_fee: None,
-                               pending_counterparty_closing_signed: None,
-                               closing_fee_limits: None,
-                               target_closing_feerate_sats_per_kw: None,
+               // If we get close to our maximum dust exposure, we end up in a situation where we can send
+               // between zero and the remaining dust exposure limit remaining OR above the dust limit.
+               // Because we cannot express this as a simple min/max, we prefer to tell the user they can
+               // send above the dust limit (as the router can always overpay to meet the dust limit).
+               let mut remaining_msat_below_dust_exposure_limit = None;
+               let mut dust_exposure_dust_limit_msat = 0;
 
-                               inbound_awaiting_accept: true,
+               let (htlc_success_dust_limit, htlc_timeout_dust_limit) = if context.opt_anchors() {
+                       (context.counterparty_dust_limit_satoshis, context.holder_dust_limit_satoshis)
+               } else {
+                       let dust_buffer_feerate = context.get_dust_buffer_feerate(None) as u64;
+                       (context.counterparty_dust_limit_satoshis + dust_buffer_feerate * htlc_success_tx_weight(false) / 1000,
+                        context.holder_dust_limit_satoshis       + dust_buffer_feerate * htlc_timeout_tx_weight(false) / 1000)
+               };
+               let on_counterparty_dust_htlc_exposure_msat = inbound_stats.on_counterparty_tx_dust_exposure_msat + outbound_stats.on_counterparty_tx_dust_exposure_msat;
+               if on_counterparty_dust_htlc_exposure_msat as i64 + htlc_success_dust_limit as i64 * 1000 - 1 > context.get_max_dust_htlc_exposure_msat() as i64 {
+                       remaining_msat_below_dust_exposure_limit =
+                               Some(context.get_max_dust_htlc_exposure_msat().saturating_sub(on_counterparty_dust_htlc_exposure_msat));
+                       dust_exposure_dust_limit_msat = cmp::max(dust_exposure_dust_limit_msat, htlc_success_dust_limit * 1000);
+               }
 
-                               funding_tx_confirmed_in: None,
-                               funding_tx_confirmation_height: 0,
-                               short_channel_id: None,
-                               channel_creation_height: current_chain_height,
+               let on_holder_dust_htlc_exposure_msat = inbound_stats.on_holder_tx_dust_exposure_msat + outbound_stats.on_holder_tx_dust_exposure_msat;
+               if on_holder_dust_htlc_exposure_msat as i64 + htlc_timeout_dust_limit as i64 * 1000 - 1 > context.get_max_dust_htlc_exposure_msat() as i64 {
+                       remaining_msat_below_dust_exposure_limit = Some(cmp::min(
+                               remaining_msat_below_dust_exposure_limit.unwrap_or(u64::max_value()),
+                               context.get_max_dust_htlc_exposure_msat().saturating_sub(on_holder_dust_htlc_exposure_msat)));
+                       dust_exposure_dust_limit_msat = cmp::max(dust_exposure_dust_limit_msat, htlc_timeout_dust_limit * 1000);
+               }
 
-                               feerate_per_kw: msg.feerate_per_kw,
-                               channel_value_satoshis: msg.funding_satoshis,
-                               counterparty_dust_limit_satoshis: msg.dust_limit_satoshis,
-                               holder_dust_limit_satoshis: MIN_CHAN_DUST_LIMIT_SATOSHIS,
-                               counterparty_max_htlc_value_in_flight_msat: cmp::min(msg.max_htlc_value_in_flight_msat, msg.funding_satoshis * 1000),
-                               holder_max_htlc_value_in_flight_msat: get_holder_max_htlc_value_in_flight_msat(msg.funding_satoshis, &config.channel_handshake_config),
-                               counterparty_selected_channel_reserve_satoshis: Some(msg.channel_reserve_satoshis),
-                               holder_selected_channel_reserve_satoshis,
-                               counterparty_htlc_minimum_msat: msg.htlc_minimum_msat,
-                               holder_htlc_minimum_msat: if config.channel_handshake_config.our_htlc_minimum_msat == 0 { 1 } else { config.channel_handshake_config.our_htlc_minimum_msat },
-                               counterparty_max_accepted_htlcs: msg.max_accepted_htlcs,
-                               holder_max_accepted_htlcs: cmp::min(config.channel_handshake_config.our_max_accepted_htlcs, MAX_HTLCS),
-                               minimum_depth: Some(cmp::max(config.channel_handshake_config.minimum_depth, 1)),
+               if let Some(remaining_limit_msat) = remaining_msat_below_dust_exposure_limit {
+                       if available_capacity_msat < dust_exposure_dust_limit_msat {
+                               available_capacity_msat = cmp::min(available_capacity_msat, remaining_limit_msat);
+                       } else {
+                               next_outbound_htlc_minimum_msat = cmp::max(next_outbound_htlc_minimum_msat, dust_exposure_dust_limit_msat);
+                       }
+               }
 
-                               counterparty_forwarding_info: None,
+               available_capacity_msat = cmp::min(available_capacity_msat,
+                       context.counterparty_max_htlc_value_in_flight_msat - outbound_stats.pending_htlcs_value_msat);
 
-                               channel_transaction_parameters: ChannelTransactionParameters {
-                                       holder_pubkeys: pubkeys,
-                                       holder_selected_contest_delay: config.channel_handshake_config.our_to_self_delay,
-                                       is_outbound_from_holder: false,
-                                       counterparty_parameters: Some(CounterpartyChannelTransactionParameters {
-                                               selected_contest_delay: msg.to_self_delay,
-                                               pubkeys: counterparty_pubkeys,
-                                       }),
-                                       funding_outpoint: None,
-                                       opt_anchors: if opt_anchors { Some(()) } else { None },
-                                       opt_non_zero_fee_anchors: None
-                               },
-                               funding_transaction: None,
+               if outbound_stats.pending_htlcs + 1 > context.counterparty_max_accepted_htlcs as u32 {
+                       available_capacity_msat = 0;
+               }
 
-                               counterparty_cur_commitment_point: Some(msg.first_per_commitment_point),
-                               counterparty_prev_commitment_point: None,
-                               counterparty_node_id,
+               AvailableBalances {
+                       inbound_capacity_msat: cmp::max(context.channel_value_satoshis as i64 * 1000
+                                       - context.value_to_self_msat as i64
+                                       - context.get_inbound_pending_htlc_stats(None).pending_htlcs_value_msat as i64
+                                       - context.holder_selected_channel_reserve_satoshis as i64 * 1000,
+                               0) as u64,
+                       outbound_capacity_msat,
+                       next_outbound_htlc_limit_msat: available_capacity_msat,
+                       next_outbound_htlc_minimum_msat,
+                       balance_msat,
+               }
+       }
 
-                               counterparty_shutdown_scriptpubkey,
+       pub fn get_holder_counterparty_selected_channel_reserve_satoshis(&self) -> (u64, Option<u64>) {
+               let context = &self;
+               (context.holder_selected_channel_reserve_satoshis, context.counterparty_selected_channel_reserve_satoshis)
+       }
 
-                               commitment_secrets: CounterpartyCommitmentSecrets::new(),
+       /// Get the commitment tx fee for the local's (i.e. our) next commitment transaction based on the
+       /// number of pending HTLCs that are on track to be in our next commitment tx.
+       ///
+       /// Optionally includes the `HTLCCandidate` given by `htlc` and an additional non-dust HTLC if
+       /// `fee_spike_buffer_htlc` is `Some`.
+       ///
+       /// The first extra HTLC is useful for determining whether we can accept a further HTLC, the
+       /// second allows for creating a buffer to ensure a further HTLC can always be accepted/added.
+       ///
+       /// Dust HTLCs are excluded.
+       fn next_local_commit_tx_fee_msat(&self, htlc: HTLCCandidate, fee_spike_buffer_htlc: Option<()>) -> u64 {
+               let context = &self;
+               assert!(context.is_outbound());
 
-                               channel_update_status: ChannelUpdateStatus::Enabled,
-                               closing_signed_in_flight: false,
+               let (htlc_success_dust_limit, htlc_timeout_dust_limit) = if context.opt_anchors() {
+                       (0, 0)
+               } else {
+                       (context.feerate_per_kw as u64 * htlc_success_tx_weight(false) / 1000,
+                               context.feerate_per_kw as u64 * htlc_timeout_tx_weight(false) / 1000)
+               };
+               let real_dust_limit_success_sat = htlc_success_dust_limit + context.holder_dust_limit_satoshis;
+               let real_dust_limit_timeout_sat = htlc_timeout_dust_limit + context.holder_dust_limit_satoshis;
 
-                               announcement_sigs: None,
+               let mut addl_htlcs = 0;
+               if fee_spike_buffer_htlc.is_some() { addl_htlcs += 1; }
+               match htlc.origin {
+                       HTLCInitiator::LocalOffered => {
+                               if htlc.amount_msat / 1000 >= real_dust_limit_timeout_sat {
+                                       addl_htlcs += 1;
+                               }
+                       },
+                       HTLCInitiator::RemoteOffered => {
+                               if htlc.amount_msat / 1000 >= real_dust_limit_success_sat {
+                                       addl_htlcs += 1;
+                               }
+                       }
+               }
 
-                               #[cfg(any(test, fuzzing))]
-                               next_local_commitment_tx_fee_info_cached: Mutex::new(None),
-                               #[cfg(any(test, fuzzing))]
-                               next_remote_commitment_tx_fee_info_cached: Mutex::new(None),
+               let mut included_htlcs = 0;
+               for ref htlc in context.pending_inbound_htlcs.iter() {
+                       if htlc.amount_msat / 1000 < real_dust_limit_success_sat {
+                               continue
+                       }
+                       // We include LocalRemoved HTLCs here because we may still need to broadcast a commitment
+                       // transaction including this HTLC if it times out before they RAA.
+                       included_htlcs += 1;
+               }
 
-                               workaround_lnd_bug_4006: None,
-                               sent_message_awaiting_response: None,
+               for ref htlc in context.pending_outbound_htlcs.iter() {
+                       if htlc.amount_msat / 1000 < real_dust_limit_timeout_sat {
+                               continue
+                       }
+                       match htlc.state {
+                               OutboundHTLCState::LocalAnnounced {..} => included_htlcs += 1,
+                               OutboundHTLCState::Committed => included_htlcs += 1,
+                               OutboundHTLCState::RemoteRemoved {..} => included_htlcs += 1,
+                               // We don't include AwaitingRemoteRevokeToRemove HTLCs because our next commitment
+                               // transaction won't be generated until they send us their next RAA, which will mean
+                               // dropping any HTLCs in this state.
+                               _ => {},
+                       }
+               }
 
-                               latest_inbound_scid_alias: None,
-                               outbound_scid_alias,
+               for htlc in context.holding_cell_htlc_updates.iter() {
+                       match htlc {
+                               &HTLCUpdateAwaitingACK::AddHTLC { amount_msat, .. } => {
+                                       if amount_msat / 1000 < real_dust_limit_timeout_sat {
+                                               continue
+                                       }
+                                       included_htlcs += 1
+                               },
+                               _ => {}, // Don't include claims/fails that are awaiting ack, because once we get the
+                                        // ack we're guaranteed to never include them in commitment txs anymore.
+                       }
+               }
 
-                               channel_pending_event_emitted: false,
-                               channel_ready_event_emitted: false,
+               let num_htlcs = included_htlcs + addl_htlcs;
+               let res = commit_tx_fee_msat(context.feerate_per_kw, num_htlcs, context.opt_anchors());
+               #[cfg(any(test, fuzzing))]
+               {
+                       let mut fee = res;
+                       if fee_spike_buffer_htlc.is_some() {
+                               fee = commit_tx_fee_msat(context.feerate_per_kw, num_htlcs - 1, context.opt_anchors());
+                       }
+                       let total_pending_htlcs = context.pending_inbound_htlcs.len() + context.pending_outbound_htlcs.len()
+                               + context.holding_cell_htlc_updates.len();
+                       let commitment_tx_info = CommitmentTxInfoCached {
+                               fee,
+                               total_pending_htlcs,
+                               next_holder_htlc_id: match htlc.origin {
+                                       HTLCInitiator::LocalOffered => context.next_holder_htlc_id + 1,
+                                       HTLCInitiator::RemoteOffered => context.next_holder_htlc_id,
+                               },
+                               next_counterparty_htlc_id: match htlc.origin {
+                                       HTLCInitiator::LocalOffered => context.next_counterparty_htlc_id,
+                                       HTLCInitiator::RemoteOffered => context.next_counterparty_htlc_id + 1,
+                               },
+                               feerate: context.feerate_per_kw,
+                       };
+                       *context.next_local_commitment_tx_fee_info_cached.lock().unwrap() = Some(commitment_tx_info);
+               }
+               res
+       }
 
-                               #[cfg(any(test, fuzzing))]
-                               historical_inbound_htlc_fulfills: HashSet::new(),
+       /// Get the commitment tx fee for the remote's next commitment transaction based on the number of
+       /// pending HTLCs that are on track to be in their next commitment tx
+       ///
+       /// Optionally includes the `HTLCCandidate` given by `htlc` and an additional non-dust HTLC if
+       /// `fee_spike_buffer_htlc` is `Some`.
+       ///
+       /// The first extra HTLC is useful for determining whether we can accept a further HTLC, the
+       /// second allows for creating a buffer to ensure a further HTLC can always be accepted/added.
+       ///
+       /// Dust HTLCs are excluded.
+       fn next_remote_commit_tx_fee_msat(&self, htlc: HTLCCandidate, fee_spike_buffer_htlc: Option<()>) -> u64 {
+               let context = &self;
+               assert!(!context.is_outbound());
 
-                               channel_type,
-                               channel_keys_id,
+               let (htlc_success_dust_limit, htlc_timeout_dust_limit) = if context.opt_anchors() {
+                       (0, 0)
+               } else {
+                       (context.feerate_per_kw as u64 * htlc_success_tx_weight(false) / 1000,
+                               context.feerate_per_kw as u64 * htlc_timeout_tx_weight(false) / 1000)
+               };
+               let real_dust_limit_success_sat = htlc_success_dust_limit + context.counterparty_dust_limit_satoshis;
+               let real_dust_limit_timeout_sat = htlc_timeout_dust_limit + context.counterparty_dust_limit_satoshis;
 
-                               pending_monitor_updates: Vec::new(),
+               let mut addl_htlcs = 0;
+               if fee_spike_buffer_htlc.is_some() { addl_htlcs += 1; }
+               match htlc.origin {
+                       HTLCInitiator::LocalOffered => {
+                               if htlc.amount_msat / 1000 >= real_dust_limit_success_sat {
+                                       addl_htlcs += 1;
+                               }
+                       },
+                       HTLCInitiator::RemoteOffered => {
+                               if htlc.amount_msat / 1000 >= real_dust_limit_timeout_sat {
+                                       addl_htlcs += 1;
+                               }
                        }
-               };
+               }
 
-               Ok(chan)
-       }
+               // When calculating the set of HTLCs which will be included in their next commitment_signed, all
+               // non-dust inbound HTLCs are included (as all states imply it will be included) and only
+               // committed outbound HTLCs, see below.
+               let mut included_htlcs = 0;
+               for ref htlc in context.pending_inbound_htlcs.iter() {
+                       if htlc.amount_msat / 1000 <= real_dust_limit_timeout_sat {
+                               continue
+                       }
+                       included_htlcs += 1;
+               }
 
-       /// Transaction nomenclature is somewhat confusing here as there are many different cases - a
-       /// transaction is referred to as "a's transaction" implying that a will be able to broadcast
-       /// the transaction. Thus, b will generally be sending a signature over such a transaction to
-       /// a, and a can revoke the transaction by providing b the relevant per_commitment_secret. As
-       /// such, a transaction is generally the result of b increasing the amount paid to a (or adding
-       /// an HTLC to a).
-       /// @local is used only to convert relevant internal structures which refer to remote vs local
-       /// to decide value of outputs and direction of HTLCs.
-       /// @generated_by_local is used to determine *which* HTLCs to include - noting that the HTLC
-       /// state may indicate that one peer has informed the other that they'd like to add an HTLC but
-       /// have not yet committed it. Such HTLCs will only be included in transactions which are being
-       /// generated by the peer which proposed adding the HTLCs, and thus we need to understand both
-       /// which peer generated this transaction and "to whom" this transaction flows.
-       #[inline]
-       fn build_commitment_transaction<L: Deref>(&self, commitment_number: u64, keys: &TxCreationKeys, local: bool, generated_by_local: bool, logger: &L) -> CommitmentStats
-               where L::Target: Logger
-       {
-               let mut included_dust_htlcs: Vec<(HTLCOutputInCommitment, Option<&HTLCSource>)> = Vec::new();
-               let num_htlcs = self.context.pending_inbound_htlcs.len() + self.context.pending_outbound_htlcs.len();
-               let mut included_non_dust_htlcs: Vec<(HTLCOutputInCommitment, Option<&HTLCSource>)> = Vec::with_capacity(num_htlcs);
-
-               let broadcaster_dust_limit_satoshis = if local { self.context.holder_dust_limit_satoshis } else { self.context.counterparty_dust_limit_satoshis };
-               let mut remote_htlc_total_msat = 0;
-               let mut local_htlc_total_msat = 0;
-               let mut value_to_self_msat_offset = 0;
-
-               let mut feerate_per_kw = self.context.feerate_per_kw;
-               if let Some((feerate, update_state)) = self.context.pending_update_fee {
-                       if match update_state {
-                               // Note that these match the inclusion criteria when scanning
-                               // pending_inbound_htlcs below.
-                               FeeUpdateState::RemoteAnnounced => { debug_assert!(!self.context.is_outbound()); !generated_by_local },
-                               FeeUpdateState::AwaitingRemoteRevokeToAnnounce => { debug_assert!(!self.context.is_outbound()); !generated_by_local },
-                               FeeUpdateState::Outbound => { assert!(self.context.is_outbound());  generated_by_local },
-                       } {
-                               feerate_per_kw = feerate;
+               for ref htlc in context.pending_outbound_htlcs.iter() {
+                       if htlc.amount_msat / 1000 <= real_dust_limit_success_sat {
+                               continue
                        }
-               }
-
-               log_trace!(logger, "Building commitment transaction number {} (really {} xor {}) for channel {} for {}, generated by {} with fee {}...",
-                       commitment_number, (INITIAL_COMMITMENT_NUMBER - commitment_number),
-                       get_commitment_transaction_number_obscure_factor(&self.get_holder_pubkeys().payment_point, &self.get_counterparty_pubkeys().payment_point, self.context.is_outbound()),
-                       log_bytes!(self.context.channel_id), if local { "us" } else { "remote" }, if generated_by_local { "us" } else { "remote" }, feerate_per_kw);
-
-               macro_rules! get_htlc_in_commitment {
-                       ($htlc: expr, $offered: expr) => {
-                               HTLCOutputInCommitment {
-                                       offered: $offered,
-                                       amount_msat: $htlc.amount_msat,
-                                       cltv_expiry: $htlc.cltv_expiry,
-                                       payment_hash: $htlc.payment_hash,
-                                       transaction_output_index: None
-                               }
+                       // We only include outbound HTLCs if it will not be included in their next commitment_signed,
+                       // i.e. if they've responded to us with an RAA after announcement.
+                       match htlc.state {
+                               OutboundHTLCState::Committed => included_htlcs += 1,
+                               OutboundHTLCState::RemoteRemoved {..} => included_htlcs += 1,
+                               OutboundHTLCState::LocalAnnounced { .. } => included_htlcs += 1,
+                               _ => {},
                        }
                }
 
-               macro_rules! add_htlc_output {
-                       ($htlc: expr, $outbound: expr, $source: expr, $state_name: expr) => {
-                               if $outbound == local { // "offered HTLC output"
-                                       let htlc_in_tx = get_htlc_in_commitment!($htlc, true);
-                                       let htlc_tx_fee = if self.context.opt_anchors() {
-                                               0
-                                       } else {
-                                               feerate_per_kw as u64 * htlc_timeout_tx_weight(false) / 1000
-                                       };
-                                       if $htlc.amount_msat / 1000 >= broadcaster_dust_limit_satoshis + htlc_tx_fee {
-                                               log_trace!(logger, "   ...including {} {} HTLC {} (hash {}) with value {}", if $outbound { "outbound" } else { "inbound" }, $state_name, $htlc.htlc_id, log_bytes!($htlc.payment_hash.0), $htlc.amount_msat);
-                                               included_non_dust_htlcs.push((htlc_in_tx, $source));
-                                       } else {
-                                               log_trace!(logger, "   ...including {} {} dust HTLC {} (hash {}) with value {} due to dust limit", if $outbound { "outbound" } else { "inbound" }, $state_name, $htlc.htlc_id, log_bytes!($htlc.payment_hash.0), $htlc.amount_msat);
-                                               included_dust_htlcs.push((htlc_in_tx, $source));
-                                       }
-                               } else {
-                                       let htlc_in_tx = get_htlc_in_commitment!($htlc, false);
-                                       let htlc_tx_fee = if self.context.opt_anchors() {
-                                               0
-                                       } else {
-                                               feerate_per_kw as u64 * htlc_success_tx_weight(false) / 1000
-                                       };
-                                       if $htlc.amount_msat / 1000 >= broadcaster_dust_limit_satoshis + htlc_tx_fee {
-                                               log_trace!(logger, "   ...including {} {} HTLC {} (hash {}) with value {}", if $outbound { "outbound" } else { "inbound" }, $state_name, $htlc.htlc_id, log_bytes!($htlc.payment_hash.0), $htlc.amount_msat);
-                                               included_non_dust_htlcs.push((htlc_in_tx, $source));
-                                       } else {
-                                               log_trace!(logger, "   ...including {} {} dust HTLC {} (hash {}) with value {}", if $outbound { "outbound" } else { "inbound" }, $state_name, $htlc.htlc_id, log_bytes!($htlc.payment_hash.0), $htlc.amount_msat);
-                                               included_dust_htlcs.push((htlc_in_tx, $source));
-                                       }
-                               }
+               let num_htlcs = included_htlcs + addl_htlcs;
+               let res = commit_tx_fee_msat(context.feerate_per_kw, num_htlcs, context.opt_anchors());
+               #[cfg(any(test, fuzzing))]
+               {
+                       let mut fee = res;
+                       if fee_spike_buffer_htlc.is_some() {
+                               fee = commit_tx_fee_msat(context.feerate_per_kw, num_htlcs - 1, context.opt_anchors());
                        }
-               }
-
-               for ref htlc in self.context.pending_inbound_htlcs.iter() {
-                       let (include, state_name) = match htlc.state {
-                               InboundHTLCState::RemoteAnnounced(_) => (!generated_by_local, "RemoteAnnounced"),
-                               InboundHTLCState::AwaitingRemoteRevokeToAnnounce(_) => (!generated_by_local, "AwaitingRemoteRevokeToAnnounce"),
-                               InboundHTLCState::AwaitingAnnouncedRemoteRevoke(_) => (true, "AwaitingAnnouncedRemoteRevoke"),
-                               InboundHTLCState::Committed => (true, "Committed"),
-                               InboundHTLCState::LocalRemoved(_) => (!generated_by_local, "LocalRemoved"),
+                       let total_pending_htlcs = context.pending_inbound_htlcs.len() + context.pending_outbound_htlcs.len();
+                       let commitment_tx_info = CommitmentTxInfoCached {
+                               fee,
+                               total_pending_htlcs,
+                               next_holder_htlc_id: match htlc.origin {
+                                       HTLCInitiator::LocalOffered => context.next_holder_htlc_id + 1,
+                                       HTLCInitiator::RemoteOffered => context.next_holder_htlc_id,
+                               },
+                               next_counterparty_htlc_id: match htlc.origin {
+                                       HTLCInitiator::LocalOffered => context.next_counterparty_htlc_id,
+                                       HTLCInitiator::RemoteOffered => context.next_counterparty_htlc_id + 1,
+                               },
+                               feerate: context.feerate_per_kw,
                        };
+                       *context.next_remote_commitment_tx_fee_info_cached.lock().unwrap() = Some(commitment_tx_info);
+               }
+               res
+       }
 
-                       if include {
-                               add_htlc_output!(htlc, false, None, state_name);
-                               remote_htlc_total_msat += htlc.amount_msat;
-                       } else {
-                               log_trace!(logger, "   ...not including inbound HTLC {} (hash {}) with value {} due to state ({})", htlc.htlc_id, log_bytes!(htlc.payment_hash.0), htlc.amount_msat, state_name);
-                               match &htlc.state {
-                                       &InboundHTLCState::LocalRemoved(ref reason) => {
-                                               if generated_by_local {
-                                                       if let &InboundHTLCRemovalReason::Fulfill(_) = reason {
-                                                               value_to_self_msat_offset += htlc.amount_msat as i64;
-                                                       }
-                                               }
-                                       },
-                                       _ => {},
-                               }
-                       }
+       /// Returns transaction if there is pending funding transaction that is yet to broadcast
+       pub fn unbroadcasted_funding(&self) -> Option<Transaction> {
+               if self.channel_state & (ChannelState::FundingCreated as u32) != 0 {
+                       self.funding_transaction.clone()
+               } else {
+                       None
                }
+       }
+}
 
-               let mut preimages: Vec<PaymentPreimage> = Vec::new();
+// Internal utility functions for channels
 
-               for ref htlc in self.context.pending_outbound_htlcs.iter() {
-                       let (include, state_name) = match htlc.state {
-                               OutboundHTLCState::LocalAnnounced(_) => (generated_by_local, "LocalAnnounced"),
-                               OutboundHTLCState::Committed => (true, "Committed"),
-                               OutboundHTLCState::RemoteRemoved(_) => (generated_by_local, "RemoteRemoved"),
-                               OutboundHTLCState::AwaitingRemoteRevokeToRemove(_) => (generated_by_local, "AwaitingRemoteRevokeToRemove"),
-                               OutboundHTLCState::AwaitingRemovedRemoteRevoke(_) => (false, "AwaitingRemovedRemoteRevoke"),
-                       };
+/// Returns the value to use for `holder_max_htlc_value_in_flight_msat` as a percentage of the
+/// `channel_value_satoshis` in msat, set through
+/// [`ChannelHandshakeConfig::max_inbound_htlc_value_in_flight_percent_of_channel`]
+///
+/// The effective percentage is lower bounded by 1% and upper bounded by 100%.
+///
+/// [`ChannelHandshakeConfig::max_inbound_htlc_value_in_flight_percent_of_channel`]: crate::util::config::ChannelHandshakeConfig::max_inbound_htlc_value_in_flight_percent_of_channel
+fn get_holder_max_htlc_value_in_flight_msat(channel_value_satoshis: u64, config: &ChannelHandshakeConfig) -> u64 {
+       let configured_percent = if config.max_inbound_htlc_value_in_flight_percent_of_channel < 1 {
+               1
+       } else if config.max_inbound_htlc_value_in_flight_percent_of_channel > 100 {
+               100
+       } else {
+               config.max_inbound_htlc_value_in_flight_percent_of_channel as u64
+       };
+       channel_value_satoshis * 10 * configured_percent
+}
 
-                       let preimage_opt = match htlc.state {
-                               OutboundHTLCState::RemoteRemoved(OutboundHTLCOutcome::Success(p)) => p,
-                               OutboundHTLCState::AwaitingRemoteRevokeToRemove(OutboundHTLCOutcome::Success(p)) => p,
-                               OutboundHTLCState::AwaitingRemovedRemoteRevoke(OutboundHTLCOutcome::Success(p)) => p,
-                               _ => None,
-                       };
+/// Returns a minimum channel reserve value the remote needs to maintain,
+/// required by us according to the configured or default
+/// [`ChannelHandshakeConfig::their_channel_reserve_proportional_millionths`]
+///
+/// Guaranteed to return a value no larger than channel_value_satoshis
+///
+/// This is used both for outbound and inbound channels and has lower bound
+/// of `MIN_THEIR_CHAN_RESERVE_SATOSHIS`.
+pub(crate) fn get_holder_selected_channel_reserve_satoshis(channel_value_satoshis: u64, config: &UserConfig) -> u64 {
+       let calculated_reserve = channel_value_satoshis.saturating_mul(config.channel_handshake_config.their_channel_reserve_proportional_millionths as u64) / 1_000_000;
+       cmp::min(channel_value_satoshis, cmp::max(calculated_reserve, MIN_THEIR_CHAN_RESERVE_SATOSHIS))
+}
 
-                       if let Some(preimage) = preimage_opt {
-                               preimages.push(preimage);
-                       }
+/// This is for legacy reasons, present for forward-compatibility.
+/// LDK versions older than 0.0.104 don't know how read/handle values other than default
+/// from storage. Hence, we use this function to not persist default values of
+/// `holder_selected_channel_reserve_satoshis` for channels into storage.
+pub(crate) fn get_legacy_default_holder_selected_channel_reserve_satoshis(channel_value_satoshis: u64) -> u64 {
+       let (q, _) = channel_value_satoshis.overflowing_div(100);
+       cmp::min(channel_value_satoshis, cmp::max(q, 1000))
+}
 
-                       if include {
-                               add_htlc_output!(htlc, true, Some(&htlc.source), state_name);
-                               local_htlc_total_msat += htlc.amount_msat;
-                       } else {
-                               log_trace!(logger, "   ...not including outbound HTLC {} (hash {}) with value {} due to state ({})", htlc.htlc_id, log_bytes!(htlc.payment_hash.0), htlc.amount_msat, state_name);
-                               match htlc.state {
-                                       OutboundHTLCState::AwaitingRemoteRevokeToRemove(OutboundHTLCOutcome::Success(_))|OutboundHTLCState::AwaitingRemovedRemoteRevoke(OutboundHTLCOutcome::Success(_)) => {
-                                               value_to_self_msat_offset -= htlc.amount_msat as i64;
-                                       },
-                                       OutboundHTLCState::RemoteRemoved(OutboundHTLCOutcome::Success(_)) => {
-                                               if !generated_by_local {
-                                                       value_to_self_msat_offset -= htlc.amount_msat as i64;
-                                               }
-                                       },
-                                       _ => {},
-                               }
-                       }
-               }
+// Get the fee cost in SATS of a commitment tx with a given number of HTLC outputs.
+// Note that num_htlcs should not include dust HTLCs.
+#[inline]
+fn commit_tx_fee_sat(feerate_per_kw: u32, num_htlcs: usize, opt_anchors: bool) -> u64 {
+       feerate_per_kw as u64 * (commitment_tx_base_weight(opt_anchors) + num_htlcs as u64 * COMMITMENT_TX_WEIGHT_PER_HTLC) / 1000
+}
 
-               let mut value_to_self_msat: i64 = (self.context.value_to_self_msat - local_htlc_total_msat) as i64 + value_to_self_msat_offset;
-               assert!(value_to_self_msat >= 0);
-               // Note that in case they have several just-awaiting-last-RAA fulfills in-progress (ie
-               // AwaitingRemoteRevokeToRemove or AwaitingRemovedRemoteRevoke) we may have allowed them to
-               // "violate" their reserve value by couting those against it. Thus, we have to convert
-               // everything to i64 before subtracting as otherwise we can overflow.
-               let mut value_to_remote_msat: i64 = (self.context.channel_value_satoshis * 1000) as i64 - (self.context.value_to_self_msat as i64) - (remote_htlc_total_msat as i64) - value_to_self_msat_offset;
-               assert!(value_to_remote_msat >= 0);
+// Get the fee cost in MSATS of a commitment tx with a given number of HTLC outputs.
+// Note that num_htlcs should not include dust HTLCs.
+fn commit_tx_fee_msat(feerate_per_kw: u32, num_htlcs: usize, opt_anchors: bool) -> u64 {
+       // Note that we need to divide before multiplying to round properly,
+       // since the lowest denomination of bitcoin on-chain is the satoshi.
+       (commitment_tx_base_weight(opt_anchors) + num_htlcs as u64 * COMMITMENT_TX_WEIGHT_PER_HTLC) * feerate_per_kw as u64 / 1000 * 1000
+}
 
-               #[cfg(debug_assertions)]
-               {
-                       // Make sure that the to_self/to_remote is always either past the appropriate
-                       // channel_reserve *or* it is making progress towards it.
-                       let mut broadcaster_max_commitment_tx_output = if generated_by_local {
-                               self.context.holder_max_commitment_tx_output.lock().unwrap()
-                       } else {
-                               self.context.counterparty_max_commitment_tx_output.lock().unwrap()
-                       };
-                       debug_assert!(broadcaster_max_commitment_tx_output.0 <= value_to_self_msat as u64 || value_to_self_msat / 1000 >= self.context.counterparty_selected_channel_reserve_satoshis.unwrap() as i64);
-                       broadcaster_max_commitment_tx_output.0 = cmp::max(broadcaster_max_commitment_tx_output.0, value_to_self_msat as u64);
-                       debug_assert!(broadcaster_max_commitment_tx_output.1 <= value_to_remote_msat as u64 || value_to_remote_msat / 1000 >= self.context.holder_selected_channel_reserve_satoshis as i64);
-                       broadcaster_max_commitment_tx_output.1 = cmp::max(broadcaster_max_commitment_tx_output.1, value_to_remote_msat as u64);
-               }
+// TODO: We should refactor this to be an Inbound/OutboundChannel until initial setup handshaking
+// has been completed, and then turn into a Channel to get compiler-time enforcement of things like
+// calling channel_id() before we're set up or things like get_outbound_funding_signed on an
+// inbound channel.
+//
+// Holder designates channel data owned for the benefit of the user client.
+// Counterparty designates channel data owned by the another channel participant entity.
+pub(super) struct Channel<Signer: ChannelSigner> {
+       pub context: ChannelContext<Signer>,
+}
 
-               let total_fee_sat = Channel::<Signer>::commit_tx_fee_sat(feerate_per_kw, included_non_dust_htlcs.len(), self.context.channel_transaction_parameters.opt_anchors.is_some());
-               let anchors_val = if self.context.channel_transaction_parameters.opt_anchors.is_some() { ANCHOR_OUTPUT_VALUE_SATOSHI * 2 } else { 0 } as i64;
-               let (value_to_self, value_to_remote) = if self.context.is_outbound() {
-                       (value_to_self_msat / 1000 - anchors_val - total_fee_sat as i64, value_to_remote_msat / 1000)
-               } else {
-                       (value_to_self_msat / 1000, value_to_remote_msat / 1000 - anchors_val - total_fee_sat as i64)
-               };
+#[cfg(any(test, fuzzing))]
+struct CommitmentTxInfoCached {
+       fee: u64,
+       total_pending_htlcs: usize,
+       next_holder_htlc_id: u64,
+       next_counterparty_htlc_id: u64,
+       feerate: u32,
+}
 
-               let mut value_to_a = if local { value_to_self } else { value_to_remote };
-               let mut value_to_b = if local { value_to_remote } else { value_to_self };
-               let (funding_pubkey_a, funding_pubkey_b) = if local {
-                       (self.get_holder_pubkeys().funding_pubkey, self.get_counterparty_pubkeys().funding_pubkey)
-               } else {
-                       (self.get_counterparty_pubkeys().funding_pubkey, self.get_holder_pubkeys().funding_pubkey)
-               };
+pub const DEFAULT_MAX_HTLCS: u16 = 50;
 
-               if value_to_a >= (broadcaster_dust_limit_satoshis as i64) {
-                       log_trace!(logger, "   ...including {} output with value {}", if local { "to_local" } else { "to_remote" }, value_to_a);
-               } else {
-                       value_to_a = 0;
-               }
+pub(crate) fn commitment_tx_base_weight(opt_anchors: bool) -> u64 {
+       const COMMITMENT_TX_BASE_WEIGHT: u64 = 724;
+       const COMMITMENT_TX_BASE_ANCHOR_WEIGHT: u64 = 1124;
+       if opt_anchors { COMMITMENT_TX_BASE_ANCHOR_WEIGHT } else { COMMITMENT_TX_BASE_WEIGHT }
+}
 
-               if value_to_b >= (broadcaster_dust_limit_satoshis as i64) {
-                       log_trace!(logger, "   ...including {} output with value {}", if local { "to_remote" } else { "to_local" }, value_to_b);
-               } else {
-                       value_to_b = 0;
-               }
+#[cfg(not(test))]
+const COMMITMENT_TX_WEIGHT_PER_HTLC: u64 = 172;
+#[cfg(test)]
+pub const COMMITMENT_TX_WEIGHT_PER_HTLC: u64 = 172;
 
-               let num_nondust_htlcs = included_non_dust_htlcs.len();
+pub const ANCHOR_OUTPUT_VALUE_SATOSHI: u64 = 330;
 
-               let channel_parameters =
-                       if local { self.context.channel_transaction_parameters.as_holder_broadcastable() }
-                       else { self.context.channel_transaction_parameters.as_counterparty_broadcastable() };
-               let tx = CommitmentTransaction::new_with_auxiliary_htlc_data(commitment_number,
-                                                                            value_to_a as u64,
-                                                                            value_to_b as u64,
-                                                                            self.context.channel_transaction_parameters.opt_anchors.is_some(),
-                                                                            funding_pubkey_a,
-                                                                            funding_pubkey_b,
-                                                                            keys.clone(),
-                                                                            feerate_per_kw,
-                                                                            &mut included_non_dust_htlcs,
-                                                                            &channel_parameters
-               );
-               let mut htlcs_included = included_non_dust_htlcs;
-               // The unwrap is safe, because all non-dust HTLCs have been assigned an output index
-               htlcs_included.sort_unstable_by_key(|h| h.0.transaction_output_index.unwrap());
-               htlcs_included.append(&mut included_dust_htlcs);
+/// The percentage of the channel value `holder_max_htlc_value_in_flight_msat` used to be set to,
+/// before this was made configurable. The percentage was made configurable in LDK 0.0.107,
+/// although LDK 0.0.104+ enabled serialization of channels with a different value set for
+/// `holder_max_htlc_value_in_flight_msat`.
+pub const MAX_IN_FLIGHT_PERCENT_LEGACY: u8 = 10;
 
-               // For the stats, trimmed-to-0 the value in msats accordingly
-               value_to_self_msat = if (value_to_self_msat * 1000) < broadcaster_dust_limit_satoshis as i64 { 0 } else { value_to_self_msat };
-               value_to_remote_msat = if (value_to_remote_msat * 1000) < broadcaster_dust_limit_satoshis as i64 { 0 } else { value_to_remote_msat };
+/// Maximum `funding_satoshis` value according to the BOLT #2 specification, if
+/// `option_support_large_channel` (aka wumbo channels) is not supported.
+/// It's 2^24 - 1.
+pub const MAX_FUNDING_SATOSHIS_NO_WUMBO: u64 = (1 << 24) - 1;
 
-               CommitmentStats {
-                       tx,
-                       feerate_per_kw,
-                       total_fee_sat,
-                       num_nondust_htlcs,
-                       htlcs_included,
-                       local_balance_msat: value_to_self_msat as u64,
-                       remote_balance_msat: value_to_remote_msat as u64,
-                       preimages
-               }
-       }
+/// Total bitcoin supply in satoshis.
+pub const TOTAL_BITCOIN_SUPPLY_SATOSHIS: u64 = 21_000_000 * 1_0000_0000;
 
-       #[inline]
-       fn get_closing_scriptpubkey(&self) -> Script {
-               // The shutdown scriptpubkey is set on channel opening when option_upfront_shutdown_script
-               // is signaled. Otherwise, it is set when sending a shutdown message. Calling this method
-               // outside of those situations will fail.
-               self.context.shutdown_scriptpubkey.clone().unwrap().into_inner()
-       }
+/// The maximum network dust limit for standard script formats. This currently represents the
+/// minimum output value for a P2SH output before Bitcoin Core 22 considers the entire
+/// transaction non-standard and thus refuses to relay it.
+/// We also use this as the maximum counterparty `dust_limit_satoshis` allowed, given many
+/// implementations use this value for their dust limit today.
+pub const MAX_STD_OUTPUT_DUST_LIMIT_SATOSHIS: u64 = 546;
 
-       #[inline]
-       fn get_closing_transaction_weight(&self, a_scriptpubkey: Option<&Script>, b_scriptpubkey: Option<&Script>) -> u64 {
-               let mut ret =
-               (4 +                                           // version
-                1 +                                           // input count
-                36 +                                          // prevout
-                1 +                                           // script length (0)
-                4 +                                           // sequence
-                1 +                                           // output count
-                4                                             // lock time
-                )*4 +                                         // * 4 for non-witness parts
-               2 +                                            // witness marker and flag
-               1 +                                            // witness element count
-               4 +                                            // 4 element lengths (2 sigs, multisig dummy, and witness script)
-               self.get_funding_redeemscript().len() as u64 + // funding witness script
-               2*(1 + 71);                                    // two signatures + sighash type flags
-               if let Some(spk) = a_scriptpubkey {
-                       ret += ((8+1) +                            // output values and script length
-                               spk.len() as u64) * 4;                 // scriptpubkey and witness multiplier
-               }
-               if let Some(spk) = b_scriptpubkey {
-                       ret += ((8+1) +                            // output values and script length
-                               spk.len() as u64) * 4;                 // scriptpubkey and witness multiplier
-               }
-               ret
-       }
+/// The maximum channel dust limit we will accept from our counterparty.
+pub const MAX_CHAN_DUST_LIMIT_SATOSHIS: u64 = MAX_STD_OUTPUT_DUST_LIMIT_SATOSHIS;
 
-       #[inline]
-       fn build_closing_transaction(&self, proposed_total_fee_satoshis: u64, skip_remote_output: bool) -> (ClosingTransaction, u64) {
-               assert!(self.context.pending_inbound_htlcs.is_empty());
-               assert!(self.context.pending_outbound_htlcs.is_empty());
-               assert!(self.context.pending_update_fee.is_none());
+/// The dust limit is used for both the commitment transaction outputs as well as the closing
+/// transactions. For cooperative closing transactions, we require segwit outputs, though accept
+/// *any* segwit scripts, which are allowed to be up to 42 bytes in length.
+/// In order to avoid having to concern ourselves with standardness during the closing process, we
+/// simply require our counterparty to use a dust limit which will leave any segwit output
+/// standard.
+/// See <https://github.com/lightning/bolts/issues/905> for more details.
+pub const MIN_CHAN_DUST_LIMIT_SATOSHIS: u64 = 354;
 
-               let mut total_fee_satoshis = proposed_total_fee_satoshis;
-               let mut value_to_holder: i64 = (self.context.value_to_self_msat as i64) / 1000 - if self.context.is_outbound() { total_fee_satoshis as i64 } else { 0 };
-               let mut value_to_counterparty: i64 = ((self.context.channel_value_satoshis * 1000 - self.context.value_to_self_msat) as i64 / 1000) - if self.context.is_outbound() { 0 } else { total_fee_satoshis as i64 };
+// Just a reasonable implementation-specific safe lower bound, higher than the dust limit.
+pub const MIN_THEIR_CHAN_RESERVE_SATOSHIS: u64 = 1000;
 
-               if value_to_holder < 0 {
-                       assert!(self.context.is_outbound());
-                       total_fee_satoshis += (-value_to_holder) as u64;
-               } else if value_to_counterparty < 0 {
-                       assert!(!self.context.is_outbound());
-                       total_fee_satoshis += (-value_to_counterparty) as u64;
+/// Used to return a simple Error back to ChannelManager. Will get converted to a
+/// msgs::ErrorAction::SendErrorMessage or msgs::ErrorAction::IgnoreError as appropriate with our
+/// channel_id in ChannelManager.
+pub(super) enum ChannelError {
+       Ignore(String),
+       Warn(String),
+       Close(String),
+}
+
+impl fmt::Debug for ChannelError {
+       fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+               match self {
+                       &ChannelError::Ignore(ref e) => write!(f, "Ignore : {}", e),
+                       &ChannelError::Warn(ref e) => write!(f, "Warn : {}", e),
+                       &ChannelError::Close(ref e) => write!(f, "Close : {}", e),
                }
+       }
+}
 
-               if skip_remote_output || value_to_counterparty as u64 <= self.context.holder_dust_limit_satoshis {
-                       value_to_counterparty = 0;
+macro_rules! secp_check {
+       ($res: expr, $err: expr) => {
+               match $res {
+                       Ok(thing) => thing,
+                       Err(_) => return Err(ChannelError::Close($err)),
                }
+       };
+}
 
-               if value_to_holder as u64 <= self.context.holder_dust_limit_satoshis {
-                       value_to_holder = 0;
+impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
+       fn get_initial_channel_type(config: &UserConfig, their_features: &InitFeatures) -> ChannelTypeFeatures {
+               // The default channel type (ie the first one we try) depends on whether the channel is
+               // public - if it is, we just go with `only_static_remotekey` as it's the only option
+               // available. If it's private, we first try `scid_privacy` as it provides better privacy
+               // with no other changes, and fall back to `only_static_remotekey`.
+               let mut ret = ChannelTypeFeatures::only_static_remote_key();
+               if !config.channel_handshake_config.announced_channel &&
+                       config.channel_handshake_config.negotiate_scid_privacy &&
+                       their_features.supports_scid_privacy() {
+                       ret.set_scid_privacy_required();
                }
 
-               assert!(self.context.shutdown_scriptpubkey.is_some());
-               let holder_shutdown_script = self.get_closing_scriptpubkey();
-               let counterparty_shutdown_script = self.context.counterparty_shutdown_scriptpubkey.clone().unwrap();
-               let funding_outpoint = self.funding_outpoint().into_bitcoin_outpoint();
+               // Optionally, if the user would like to negotiate the `anchors_zero_fee_htlc_tx` option, we
+               // set it now. If they don't understand it, we'll fall back to our default of
+               // `only_static_remotekey`.
+               #[cfg(anchors)]
+               { // Attributes are not allowed on if expressions on our current MSRV of 1.41.
+                       if config.channel_handshake_config.negotiate_anchors_zero_fee_htlc_tx &&
+                               their_features.supports_anchors_zero_fee_htlc_tx() {
+                               ret.set_anchors_zero_fee_htlc_tx_required();
+                       }
+               }
 
-               let closing_transaction = ClosingTransaction::new(value_to_holder as u64, value_to_counterparty as u64, holder_shutdown_script, counterparty_shutdown_script, funding_outpoint);
-               (closing_transaction, total_fee_satoshis)
+               ret
        }
 
-       fn funding_outpoint(&self) -> OutPoint {
-               self.context.channel_transaction_parameters.funding_outpoint.unwrap()
+       /// If we receive an error message, it may only be a rejection of the channel type we tried,
+       /// not of our ability to open any channel at all. Thus, on error, we should first call this
+       /// and see if we get a new `OpenChannel` message, otherwise the channel is failed.
+       pub(crate) fn maybe_handle_error_without_close(&mut self, chain_hash: BlockHash) -> Result<msgs::OpenChannel, ()> {
+               if !self.context.is_outbound() || self.context.channel_state != ChannelState::OurInitSent as u32 { return Err(()); }
+               if self.context.channel_type == ChannelTypeFeatures::only_static_remote_key() {
+                       // We've exhausted our options
+                       return Err(());
+               }
+               // We support opening a few different types of channels. Try removing our additional
+               // features one by one until we've either arrived at our default or the counterparty has
+               // accepted one.
+               //
+               // Due to the order below, we may not negotiate `option_anchors_zero_fee_htlc_tx` if the
+               // counterparty doesn't support `option_scid_privacy`. Since `get_initial_channel_type`
+               // checks whether the counterparty supports every feature, this would only happen if the
+               // counterparty is advertising the feature, but rejecting channels proposing the feature for
+               // whatever reason.
+               if self.context.channel_type.supports_anchors_zero_fee_htlc_tx() {
+                       self.context.channel_type.clear_anchors_zero_fee_htlc_tx();
+                       assert!(self.context.channel_transaction_parameters.opt_non_zero_fee_anchors.is_none());
+                       self.context.channel_transaction_parameters.opt_anchors = None;
+               } else if self.context.channel_type.supports_scid_privacy() {
+                       self.context.channel_type.clear_scid_privacy();
+               } else {
+                       self.context.channel_type = ChannelTypeFeatures::only_static_remote_key();
+               }
+               Ok(self.get_open_channel(chain_hash))
        }
 
-       #[inline]
-       /// Creates a set of keys for build_commitment_transaction to generate a transaction which our
-       /// counterparty will sign (ie DO NOT send signatures over a transaction created by this to
-       /// our counterparty!)
-       /// The result is a transaction which we can revoke broadcastership of (ie a "local" transaction)
-       /// TODO Some magic rust shit to compile-time check this?
-       fn build_holder_transaction_keys(&self, commitment_number: u64) -> TxCreationKeys {
-               let per_commitment_point = self.context.holder_signer.get_per_commitment_point(commitment_number, &self.context.secp_ctx);
-               let delayed_payment_base = &self.get_holder_pubkeys().delayed_payment_basepoint;
-               let htlc_basepoint = &self.get_holder_pubkeys().htlc_basepoint;
-               let counterparty_pubkeys = self.get_counterparty_pubkeys();
+       // Constructors:
+       pub fn new_outbound<ES: Deref, SP: Deref, F: Deref>(
+               fee_estimator: &LowerBoundedFeeEstimator<F>, entropy_source: &ES, signer_provider: &SP, counterparty_node_id: PublicKey, their_features: &InitFeatures,
+               channel_value_satoshis: u64, push_msat: u64, user_id: u128, config: &UserConfig, current_chain_height: u32,
+               outbound_scid_alias: u64
+       ) -> Result<Channel<Signer>, APIError>
+       where ES::Target: EntropySource,
+             SP::Target: SignerProvider<Signer = Signer>,
+             F::Target: FeeEstimator,
+       {
+               let holder_selected_contest_delay = config.channel_handshake_config.our_to_self_delay;
+               let channel_keys_id = signer_provider.generate_channel_keys_id(false, channel_value_satoshis, user_id);
+               let holder_signer = signer_provider.derive_channel_signer(channel_value_satoshis, channel_keys_id);
+               let pubkeys = holder_signer.pubkeys().clone();
 
-               TxCreationKeys::derive_new(&self.context.secp_ctx, &per_commitment_point, delayed_payment_base, htlc_basepoint, &counterparty_pubkeys.revocation_basepoint, &counterparty_pubkeys.htlc_basepoint)
-       }
+               if !their_features.supports_wumbo() && channel_value_satoshis > MAX_FUNDING_SATOSHIS_NO_WUMBO {
+                       return Err(APIError::APIMisuseError{err: format!("funding_value must not exceed {}, it was {}", MAX_FUNDING_SATOSHIS_NO_WUMBO, channel_value_satoshis)});
+               }
+               if channel_value_satoshis >= TOTAL_BITCOIN_SUPPLY_SATOSHIS {
+                       return Err(APIError::APIMisuseError{err: format!("funding_value must be smaller than the total bitcoin supply, it was {}", channel_value_satoshis)});
+               }
+               let channel_value_msat = channel_value_satoshis * 1000;
+               if push_msat > channel_value_msat {
+                       return Err(APIError::APIMisuseError { err: format!("Push value ({}) was larger than channel_value ({})", push_msat, channel_value_msat) });
+               }
+               if holder_selected_contest_delay < BREAKDOWN_TIMEOUT {
+                       return Err(APIError::APIMisuseError {err: format!("Configured with an unreasonable our_to_self_delay ({}) putting user funds at risks", holder_selected_contest_delay)});
+               }
+               let holder_selected_channel_reserve_satoshis = get_holder_selected_channel_reserve_satoshis(channel_value_satoshis, config);
+               if holder_selected_channel_reserve_satoshis < MIN_CHAN_DUST_LIMIT_SATOSHIS {
+                       // Protocol level safety check in place, although it should never happen because
+                       // of `MIN_THEIR_CHAN_RESERVE_SATOSHIS`
+                       return Err(APIError::APIMisuseError { err: format!("Holder selected channel  reserve below implemention limit dust_limit_satoshis {}", holder_selected_channel_reserve_satoshis) });
+               }
 
-       #[inline]
-       /// Creates a set of keys for build_commitment_transaction to generate a transaction which we
-       /// will sign and send to our counterparty.
-       /// If an Err is returned, it is a ChannelError::Close (for get_outbound_funding_created)
-       fn build_remote_transaction_keys(&self) -> TxCreationKeys {
-               //TODO: Ensure that the payment_key derived here ends up in the library users' wallet as we
-               //may see payments to it!
-               let revocation_basepoint = &self.get_holder_pubkeys().revocation_basepoint;
-               let htlc_basepoint = &self.get_holder_pubkeys().htlc_basepoint;
-               let counterparty_pubkeys = self.get_counterparty_pubkeys();
+               let channel_type = Self::get_initial_channel_type(&config, their_features);
+               debug_assert!(channel_type.is_subset(&channelmanager::provided_channel_type_features(&config)));
 
-               TxCreationKeys::derive_new(&self.context.secp_ctx, &self.context.counterparty_cur_commitment_point.unwrap(), &counterparty_pubkeys.delayed_payment_basepoint, &counterparty_pubkeys.htlc_basepoint, revocation_basepoint, htlc_basepoint)
-       }
+               let feerate = fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::Normal);
 
-       /// Gets the redeemscript for the funding transaction output (ie the funding transaction output
-       /// pays to get_funding_redeemscript().to_v0_p2wsh()).
-       /// Panics if called before accept_channel/new_from_req
-       pub fn get_funding_redeemscript(&self) -> Script {
-               make_funding_redeemscript(&self.get_holder_pubkeys().funding_pubkey, self.counterparty_funding_pubkey())
-       }
+               let value_to_self_msat = channel_value_satoshis * 1000 - push_msat;
+               let commitment_tx_fee = commit_tx_fee_msat(feerate, MIN_AFFORDABLE_HTLC_COUNT, channel_type.requires_anchors_zero_fee_htlc_tx());
+               if value_to_self_msat < commitment_tx_fee {
+                       return Err(APIError::APIMisuseError{ err: format!("Funding amount ({}) can't even pay fee for initial commitment transaction fee of {}.", value_to_self_msat / 1000, commitment_tx_fee / 1000) });
+               }
 
-       /// Claims an HTLC while we're disconnected from a peer, dropping the [`ChannelMonitorUpdate`]
-       /// entirely.
-       ///
-       /// The [`ChannelMonitor`] for this channel MUST be updated out-of-band with the preimage
-       /// provided (i.e. without calling [`crate::chain::Watch::update_channel`]).
-       ///
-       /// The HTLC claim will end up in the holding cell (because the caller must ensure the peer is
-       /// disconnected).
-       pub fn claim_htlc_while_disconnected_dropping_mon_update<L: Deref>
-               (&mut self, htlc_id_arg: u64, payment_preimage_arg: PaymentPreimage, logger: &L)
-       where L::Target: Logger {
-               // Assert that we'll add the HTLC claim to the holding cell in `get_update_fulfill_htlc`
-               // (see equivalent if condition there).
-               assert!(self.context.channel_state & (ChannelState::AwaitingRemoteRevoke as u32 | ChannelState::PeerDisconnected as u32 | ChannelState::MonitorUpdateInProgress as u32) != 0);
-               let mon_update_id = self.context.latest_monitor_update_id; // Forget the ChannelMonitor update
-               let fulfill_resp = self.get_update_fulfill_htlc(htlc_id_arg, payment_preimage_arg, logger);
-               self.context.latest_monitor_update_id = mon_update_id;
-               if let UpdateFulfillFetch::NewClaim { msg, .. } = fulfill_resp {
-                       assert!(msg.is_none()); // The HTLC must have ended up in the holding cell.
-               }
-       }
-
-       fn get_update_fulfill_htlc<L: Deref>(&mut self, htlc_id_arg: u64, payment_preimage_arg: PaymentPreimage, logger: &L) -> UpdateFulfillFetch where L::Target: Logger {
-               // Either ChannelReady got set (which means it won't be unset) or there is no way any
-               // caller thought we could have something claimed (cause we wouldn't have accepted in an
-               // incoming HTLC anyway). If we got to ShutdownComplete, callers aren't allowed to call us,
-               // either.
-               if (self.context.channel_state & (ChannelState::ChannelReady as u32)) != (ChannelState::ChannelReady as u32) {
-                       panic!("Was asked to fulfill an HTLC when channel was not in an operational state");
-               }
-               assert_eq!(self.context.channel_state & ChannelState::ShutdownComplete as u32, 0);
-
-               let payment_hash_calc = PaymentHash(Sha256::hash(&payment_preimage_arg.0[..]).into_inner());
+               let mut secp_ctx = Secp256k1::new();
+               secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
 
-               // ChannelManager may generate duplicate claims/fails due to HTLC update events from
-               // on-chain ChannelsMonitors during block rescan. Ideally we'd figure out a way to drop
-               // these, but for now we just have to treat them as normal.
+               let shutdown_scriptpubkey = if config.channel_handshake_config.commit_upfront_shutdown_pubkey {
+                       match signer_provider.get_shutdown_scriptpubkey() {
+                               Ok(scriptpubkey) => Some(scriptpubkey),
+                               Err(_) => return Err(APIError::ChannelUnavailable { err: "Failed to get shutdown scriptpubkey".to_owned()}),
+                       }
+               } else { None };
 
-               let mut pending_idx = core::usize::MAX;
-               let mut htlc_value_msat = 0;
-               for (idx, htlc) in self.context.pending_inbound_htlcs.iter().enumerate() {
-                       if htlc.htlc_id == htlc_id_arg {
-                               assert_eq!(htlc.payment_hash, payment_hash_calc);
-                               match htlc.state {
-                                       InboundHTLCState::Committed => {},
-                                       InboundHTLCState::LocalRemoved(ref reason) => {
-                                               if let &InboundHTLCRemovalReason::Fulfill(_) = reason {
-                                               } else {
-                                                       log_warn!(logger, "Have preimage and want to fulfill HTLC with payment hash {} we already failed against channel {}", log_bytes!(htlc.payment_hash.0), log_bytes!(self.channel_id()));
-                                                       debug_assert!(false, "Tried to fulfill an HTLC that was already failed");
-                                               }
-                                               return UpdateFulfillFetch::DuplicateClaim {};
-                                       },
-                                       _ => {
-                                               debug_assert!(false, "Have an inbound HTLC we tried to claim before it was fully committed to");
-                                               // Don't return in release mode here so that we can update channel_monitor
-                                       }
-                               }
-                               pending_idx = idx;
-                               htlc_value_msat = htlc.amount_msat;
-                               break;
+               if let Some(shutdown_scriptpubkey) = &shutdown_scriptpubkey {
+                       if !shutdown_scriptpubkey.is_compatible(&their_features) {
+                               return Err(APIError::IncompatibleShutdownScript { script: shutdown_scriptpubkey.clone() });
                        }
                }
-               if pending_idx == core::usize::MAX {
-                       #[cfg(any(test, fuzzing))]
-                       // If we failed to find an HTLC to fulfill, make sure it was previously fulfilled and
-                       // this is simply a duplicate claim, not previously failed and we lost funds.
-                       debug_assert!(self.context.historical_inbound_htlc_fulfills.contains(&htlc_id_arg));
-                       return UpdateFulfillFetch::DuplicateClaim {};
-               }
 
-               // Now update local state:
-               //
-               // We have to put the payment_preimage in the channel_monitor right away here to ensure we
-               // can claim it even if the channel hits the chain before we see their next commitment.
-               self.context.latest_monitor_update_id += 1;
-               let monitor_update = ChannelMonitorUpdate {
-                       update_id: self.context.latest_monitor_update_id,
-                       updates: vec![ChannelMonitorUpdateStep::PaymentPreimage {
-                               payment_preimage: payment_preimage_arg.clone(),
-                       }],
+               let destination_script = match signer_provider.get_destination_script() {
+                       Ok(script) => script,
+                       Err(_) => return Err(APIError::ChannelUnavailable { err: "Failed to get destination script".to_owned()}),
                };
 
-               if (self.context.channel_state & (ChannelState::AwaitingRemoteRevoke as u32 | ChannelState::PeerDisconnected as u32 | ChannelState::MonitorUpdateInProgress as u32)) != 0 {
-                       // Note that this condition is the same as the assertion in
-                       // `claim_htlc_while_disconnected_dropping_mon_update` and must match exactly -
-                       // `claim_htlc_while_disconnected_dropping_mon_update` would not work correctly if we
-                       // do not not get into this branch.
-                       for pending_update in self.context.holding_cell_htlc_updates.iter() {
-                               match pending_update {
-                                       &HTLCUpdateAwaitingACK::ClaimHTLC { htlc_id, .. } => {
-                                               if htlc_id_arg == htlc_id {
-                                                       // Make sure we don't leave latest_monitor_update_id incremented here:
-                                                       self.context.latest_monitor_update_id -= 1;
-                                                       #[cfg(any(test, fuzzing))]
-                                                       debug_assert!(self.context.historical_inbound_htlc_fulfills.contains(&htlc_id_arg));
-                                                       return UpdateFulfillFetch::DuplicateClaim {};
-                                               }
-                                       },
-                                       &HTLCUpdateAwaitingACK::FailHTLC { htlc_id, .. } => {
-                                               if htlc_id_arg == htlc_id {
-                                                       log_warn!(logger, "Have preimage and want to fulfill HTLC with pending failure against channel {}", log_bytes!(self.channel_id()));
-                                                       // TODO: We may actually be able to switch to a fulfill here, though its
-                                                       // rare enough it may not be worth the complexity burden.
-                                                       debug_assert!(false, "Tried to fulfill an HTLC that was already failed");
-                                                       return UpdateFulfillFetch::NewClaim { monitor_update, htlc_value_msat, msg: None };
-                                               }
-                                       },
-                                       _ => {}
-                               }
-                       }
-                       log_trace!(logger, "Adding HTLC claim to holding_cell in channel {}! Current state: {}", log_bytes!(self.channel_id()), self.context.channel_state);
-                       self.context.holding_cell_htlc_updates.push(HTLCUpdateAwaitingACK::ClaimHTLC {
-                               payment_preimage: payment_preimage_arg, htlc_id: htlc_id_arg,
-                       });
-                       #[cfg(any(test, fuzzing))]
-                       self.context.historical_inbound_htlc_fulfills.insert(htlc_id_arg);
-                       return UpdateFulfillFetch::NewClaim { monitor_update, htlc_value_msat, msg: None };
-               }
-               #[cfg(any(test, fuzzing))]
-               self.context.historical_inbound_htlc_fulfills.insert(htlc_id_arg);
+               let temporary_channel_id = entropy_source.get_secure_random_bytes();
 
-               {
-                       let htlc = &mut self.context.pending_inbound_htlcs[pending_idx];
-                       if let InboundHTLCState::Committed = htlc.state {
-                       } else {
-                               debug_assert!(false, "Have an inbound HTLC we tried to claim before it was fully committed to");
-                               return UpdateFulfillFetch::NewClaim { monitor_update, htlc_value_msat, msg: None };
-                       }
-                       log_trace!(logger, "Upgrading HTLC {} to LocalRemoved with a Fulfill in channel {}!", log_bytes!(htlc.payment_hash.0), log_bytes!(self.context.channel_id));
-                       htlc.state = InboundHTLCState::LocalRemoved(InboundHTLCRemovalReason::Fulfill(payment_preimage_arg.clone()));
-               }
+               Ok(Channel {
+                       context: ChannelContext {
+                               user_id,
 
-               UpdateFulfillFetch::NewClaim {
-                       monitor_update,
-                       htlc_value_msat,
-                       msg: Some(msgs::UpdateFulfillHTLC {
-                               channel_id: self.channel_id(),
-                               htlc_id: htlc_id_arg,
-                               payment_preimage: payment_preimage_arg,
-                       }),
-               }
-       }
+                               config: LegacyChannelConfig {
+                                       options: config.channel_config.clone(),
+                                       announced_channel: config.channel_handshake_config.announced_channel,
+                                       commit_upfront_shutdown_pubkey: config.channel_handshake_config.commit_upfront_shutdown_pubkey,
+                               },
 
-       pub fn get_update_fulfill_htlc_and_commit<L: Deref>(&mut self, htlc_id: u64, payment_preimage: PaymentPreimage, logger: &L) -> UpdateFulfillCommitFetch where L::Target: Logger {
-               let release_cs_monitor = self.context.pending_monitor_updates.iter().all(|upd| !upd.blocked);
-               match self.get_update_fulfill_htlc(htlc_id, payment_preimage, logger) {
-                       UpdateFulfillFetch::NewClaim { mut monitor_update, htlc_value_msat, msg } => {
-                               // Even if we aren't supposed to let new monitor updates with commitment state
-                               // updates run, we still need to push the preimage ChannelMonitorUpdateStep no
-                               // matter what. Sadly, to push a new monitor update which flies before others
-                               // already queued, we have to insert it into the pending queue and update the
-                               // update_ids of all the following monitors.
-                               let unblocked_update_pos = if release_cs_monitor && msg.is_some() {
-                                       let mut additional_update = self.build_commitment_no_status_check(logger);
-                                       // build_commitment_no_status_check may bump latest_monitor_id but we want them
-                                       // to be strictly increasing by one, so decrement it here.
-                                       self.context.latest_monitor_update_id = monitor_update.update_id;
-                                       monitor_update.updates.append(&mut additional_update.updates);
-                                       self.context.pending_monitor_updates.push(PendingChannelMonitorUpdate {
-                                               update: monitor_update, blocked: false,
-                                       });
-                                       self.context.pending_monitor_updates.len() - 1
-                               } else {
-                                       let insert_pos = self.context.pending_monitor_updates.iter().position(|upd| upd.blocked)
-                                               .unwrap_or(self.context.pending_monitor_updates.len());
-                                       let new_mon_id = self.context.pending_monitor_updates.get(insert_pos)
-                                               .map(|upd| upd.update.update_id).unwrap_or(monitor_update.update_id);
-                                       monitor_update.update_id = new_mon_id;
-                                       self.context.pending_monitor_updates.insert(insert_pos, PendingChannelMonitorUpdate {
-                                               update: monitor_update, blocked: false,
-                                       });
-                                       for held_update in self.context.pending_monitor_updates.iter_mut().skip(insert_pos + 1) {
-                                               held_update.update.update_id += 1;
-                                       }
-                                       if msg.is_some() {
-                                               debug_assert!(false, "If there is a pending blocked monitor we should have MonitorUpdateInProgress set");
-                                               let update = self.build_commitment_no_status_check(logger);
-                                               self.context.pending_monitor_updates.push(PendingChannelMonitorUpdate {
-                                                       update, blocked: true,
-                                               });
-                                       }
-                                       insert_pos
-                               };
-                               self.monitor_updating_paused(false, msg.is_some(), false, Vec::new(), Vec::new(), Vec::new());
-                               UpdateFulfillCommitFetch::NewClaim {
-                                       monitor_update: &self.context.pending_monitor_updates.get(unblocked_update_pos)
-                                               .expect("We just pushed the monitor update").update,
-                                       htlc_value_msat,
-                               }
-                       },
-                       UpdateFulfillFetch::DuplicateClaim {} => UpdateFulfillCommitFetch::DuplicateClaim {},
-               }
-       }
+                               prev_config: None,
 
-       /// We can only have one resolution per HTLC. In some cases around reconnect, we may fulfill
-       /// an HTLC more than once or fulfill once and then attempt to fail after reconnect. We cannot,
-       /// however, fail more than once as we wait for an upstream failure to be irrevocably committed
-       /// before we fail backwards.
-       ///
-       /// If we do fail twice, we `debug_assert!(false)` and return `Ok(None)`. Thus, this will always
-       /// return `Ok(_)` if preconditions are met. In any case, `Err`s will only be
-       /// [`ChannelError::Ignore`].
-       pub fn queue_fail_htlc<L: Deref>(&mut self, htlc_id_arg: u64, err_packet: msgs::OnionErrorPacket, logger: &L)
-       -> Result<(), ChannelError> where L::Target: Logger {
-               self.fail_htlc(htlc_id_arg, err_packet, true, logger)
-                       .map(|msg_opt| assert!(msg_opt.is_none(), "We forced holding cell?"))
-       }
+                               inbound_handshake_limits_override: Some(config.channel_handshake_limits.clone()),
+
+                               channel_id: temporary_channel_id,
+                               temporary_channel_id: Some(temporary_channel_id),
+                               channel_state: ChannelState::OurInitSent as u32,
+                               announcement_sigs_state: AnnouncementSigsState::NotSent,
+                               secp_ctx,
+                               channel_value_satoshis,
+
+                               latest_monitor_update_id: 0,
+
+                               holder_signer,
+                               shutdown_scriptpubkey,
+                               destination_script,
+
+                               cur_holder_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
+                               cur_counterparty_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
+                               value_to_self_msat,
+
+                               pending_inbound_htlcs: Vec::new(),
+                               pending_outbound_htlcs: Vec::new(),
+                               holding_cell_htlc_updates: Vec::new(),
+                               pending_update_fee: None,
+                               holding_cell_update_fee: None,
+                               next_holder_htlc_id: 0,
+                               next_counterparty_htlc_id: 0,
+                               update_time_counter: 1,
+
+                               resend_order: RAACommitmentOrder::CommitmentFirst,
+
+                               monitor_pending_channel_ready: false,
+                               monitor_pending_revoke_and_ack: false,
+                               monitor_pending_commitment_signed: false,
+                               monitor_pending_forwards: Vec::new(),
+                               monitor_pending_failures: Vec::new(),
+                               monitor_pending_finalized_fulfills: Vec::new(),
+
+                               #[cfg(debug_assertions)]
+                               holder_max_commitment_tx_output: Mutex::new((channel_value_satoshis * 1000 - push_msat, push_msat)),
+                               #[cfg(debug_assertions)]
+                               counterparty_max_commitment_tx_output: Mutex::new((channel_value_satoshis * 1000 - push_msat, push_msat)),
+
+                               last_sent_closing_fee: None,
+                               pending_counterparty_closing_signed: None,
+                               closing_fee_limits: None,
+                               target_closing_feerate_sats_per_kw: None,
+
+                               inbound_awaiting_accept: false,
+
+                               funding_tx_confirmed_in: None,
+                               funding_tx_confirmation_height: 0,
+                               short_channel_id: None,
+                               channel_creation_height: current_chain_height,
+
+                               feerate_per_kw: feerate,
+                               counterparty_dust_limit_satoshis: 0,
+                               holder_dust_limit_satoshis: MIN_CHAN_DUST_LIMIT_SATOSHIS,
+                               counterparty_max_htlc_value_in_flight_msat: 0,
+                               holder_max_htlc_value_in_flight_msat: get_holder_max_htlc_value_in_flight_msat(channel_value_satoshis, &config.channel_handshake_config),
+                               counterparty_selected_channel_reserve_satoshis: None, // Filled in in accept_channel
+                               holder_selected_channel_reserve_satoshis,
+                               counterparty_htlc_minimum_msat: 0,
+                               holder_htlc_minimum_msat: if config.channel_handshake_config.our_htlc_minimum_msat == 0 { 1 } else { config.channel_handshake_config.our_htlc_minimum_msat },
+                               counterparty_max_accepted_htlcs: 0,
+                               holder_max_accepted_htlcs: cmp::min(config.channel_handshake_config.our_max_accepted_htlcs, MAX_HTLCS),
+                               minimum_depth: None, // Filled in in accept_channel
+
+                               counterparty_forwarding_info: None,
+
+                               channel_transaction_parameters: ChannelTransactionParameters {
+                                       holder_pubkeys: pubkeys,
+                                       holder_selected_contest_delay: config.channel_handshake_config.our_to_self_delay,
+                                       is_outbound_from_holder: true,
+                                       counterparty_parameters: None,
+                                       funding_outpoint: None,
+                                       opt_anchors: if channel_type.requires_anchors_zero_fee_htlc_tx() { Some(()) } else { None },
+                                       opt_non_zero_fee_anchors: None
+                               },
+                               funding_transaction: None,
+
+                               counterparty_cur_commitment_point: None,
+                               counterparty_prev_commitment_point: None,
+                               counterparty_node_id,
+
+                               counterparty_shutdown_scriptpubkey: None,
+
+                               commitment_secrets: CounterpartyCommitmentSecrets::new(),
+
+                               channel_update_status: ChannelUpdateStatus::Enabled,
+                               closing_signed_in_flight: false,
+
+                               announcement_sigs: None,
+
+                               #[cfg(any(test, fuzzing))]
+                               next_local_commitment_tx_fee_info_cached: Mutex::new(None),
+                               #[cfg(any(test, fuzzing))]
+                               next_remote_commitment_tx_fee_info_cached: Mutex::new(None),
+
+                               workaround_lnd_bug_4006: None,
+                               sent_message_awaiting_response: None,
 
-       /// We can only have one resolution per HTLC. In some cases around reconnect, we may fulfill
-       /// an HTLC more than once or fulfill once and then attempt to fail after reconnect. We cannot,
-       /// however, fail more than once as we wait for an upstream failure to be irrevocably committed
-       /// before we fail backwards.
-       ///
-       /// If we do fail twice, we `debug_assert!(false)` and return `Ok(None)`. Thus, this will always
-       /// return `Ok(_)` if preconditions are met. In any case, `Err`s will only be
-       /// [`ChannelError::Ignore`].
-       fn fail_htlc<L: Deref>(&mut self, htlc_id_arg: u64, err_packet: msgs::OnionErrorPacket, mut force_holding_cell: bool, logger: &L)
-       -> Result<Option<msgs::UpdateFailHTLC>, ChannelError> where L::Target: Logger {
-               if (self.context.channel_state & (ChannelState::ChannelReady as u32)) != (ChannelState::ChannelReady as u32) {
-                       panic!("Was asked to fail an HTLC when channel was not in an operational state");
-               }
-               assert_eq!(self.context.channel_state & ChannelState::ShutdownComplete as u32, 0);
+                               latest_inbound_scid_alias: None,
+                               outbound_scid_alias,
 
-               // ChannelManager may generate duplicate claims/fails due to HTLC update events from
-               // on-chain ChannelsMonitors during block rescan. Ideally we'd figure out a way to drop
-               // these, but for now we just have to treat them as normal.
+                               channel_pending_event_emitted: false,
+                               channel_ready_event_emitted: false,
 
-               let mut pending_idx = core::usize::MAX;
-               for (idx, htlc) in self.context.pending_inbound_htlcs.iter().enumerate() {
-                       if htlc.htlc_id == htlc_id_arg {
-                               match htlc.state {
-                                       InboundHTLCState::Committed => {},
-                                       InboundHTLCState::LocalRemoved(ref reason) => {
-                                               if let &InboundHTLCRemovalReason::Fulfill(_) = reason {
-                                               } else {
-                                                       debug_assert!(false, "Tried to fail an HTLC that was already failed");
-                                               }
-                                               return Ok(None);
-                                       },
-                                       _ => {
-                                               debug_assert!(false, "Have an inbound HTLC we tried to claim before it was fully committed to");
-                                               return Err(ChannelError::Ignore(format!("Unable to find a pending HTLC which matched the given HTLC ID ({})", htlc.htlc_id)));
-                                       }
-                               }
-                               pending_idx = idx;
+                               #[cfg(any(test, fuzzing))]
+                               historical_inbound_htlc_fulfills: HashSet::new(),
+
+                               channel_type,
+                               channel_keys_id,
+
+                               pending_monitor_updates: Vec::new(),
                        }
-               }
-               if pending_idx == core::usize::MAX {
-                       #[cfg(any(test, fuzzing))]
-                       // If we failed to find an HTLC to fail, make sure it was previously fulfilled and this
-                       // is simply a duplicate fail, not previously failed and we failed-back too early.
-                       debug_assert!(self.context.historical_inbound_htlc_fulfills.contains(&htlc_id_arg));
-                       return Ok(None);
-               }
+               })
+       }
 
-               if (self.context.channel_state & (ChannelState::AwaitingRemoteRevoke as u32 | ChannelState::PeerDisconnected as u32 | ChannelState::MonitorUpdateInProgress as u32)) != 0 {
-                       debug_assert!(force_holding_cell, "!force_holding_cell is only called when emptying the holding cell, so we shouldn't end up back in it!");
-                       force_holding_cell = true;
+       fn check_remote_fee<F: Deref, L: Deref>(fee_estimator: &LowerBoundedFeeEstimator<F>,
+               feerate_per_kw: u32, cur_feerate_per_kw: Option<u32>, logger: &L)
+               -> Result<(), ChannelError> where F::Target: FeeEstimator, L::Target: Logger,
+       {
+               // We only bound the fee updates on the upper side to prevent completely absurd feerates,
+               // always accepting up to 25 sat/vByte or 10x our fee estimator's "High Priority" fee.
+               // We generally don't care too much if they set the feerate to something very high, but it
+               // could result in the channel being useless due to everything being dust.
+               let upper_limit = cmp::max(250 * 25,
+                       fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::HighPriority) as u64 * 10);
+               if feerate_per_kw as u64 > upper_limit {
+                       return Err(ChannelError::Close(format!("Peer's feerate much too high. Actual: {}. Our expected upper limit: {}", feerate_per_kw, upper_limit)));
                }
-
-               // Now update local state:
-               if force_holding_cell {
-                       for pending_update in self.context.holding_cell_htlc_updates.iter() {
-                               match pending_update {
-                                       &HTLCUpdateAwaitingACK::ClaimHTLC { htlc_id, .. } => {
-                                               if htlc_id_arg == htlc_id {
-                                                       #[cfg(any(test, fuzzing))]
-                                                       debug_assert!(self.context.historical_inbound_htlc_fulfills.contains(&htlc_id_arg));
-                                                       return Ok(None);
-                                               }
-                                       },
-                                       &HTLCUpdateAwaitingACK::FailHTLC { htlc_id, .. } => {
-                                               if htlc_id_arg == htlc_id {
-                                                       debug_assert!(false, "Tried to fail an HTLC that was already failed");
-                                                       return Err(ChannelError::Ignore("Unable to find a pending HTLC which matched the given HTLC ID".to_owned()));
-                                               }
-                                       },
-                                       _ => {}
+               let lower_limit = fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::Background);
+               // Some fee estimators round up to the next full sat/vbyte (ie 250 sats per kw), causing
+               // occasional issues with feerate disagreements between an initiator that wants a feerate
+               // of 1.1 sat/vbyte and a receiver that wants 1.1 rounded up to 2. Thus, we always add 250
+               // sat/kw before the comparison here.
+               if feerate_per_kw + 250 < lower_limit {
+                       if let Some(cur_feerate) = cur_feerate_per_kw {
+                               if feerate_per_kw > cur_feerate {
+                                       log_warn!(logger,
+                                               "Accepting feerate that may prevent us from closing this channel because it's higher than what we have now. Had {} s/kW, now {} s/kW.",
+                                               cur_feerate, feerate_per_kw);
+                                       return Ok(());
                                }
                        }
-                       log_trace!(logger, "Placing failure for HTLC ID {} in holding cell in channel {}.", htlc_id_arg, log_bytes!(self.channel_id()));
-                       self.context.holding_cell_htlc_updates.push(HTLCUpdateAwaitingACK::FailHTLC {
-                               htlc_id: htlc_id_arg,
-                               err_packet,
-                       });
-                       return Ok(None);
+                       return Err(ChannelError::Close(format!("Peer's feerate much too low. Actual: {}. Our expected lower limit: {} (- 250)", feerate_per_kw, lower_limit)));
                }
+               Ok(())
+       }
 
-               log_trace!(logger, "Failing HTLC ID {} back with a update_fail_htlc message in channel {}.", htlc_id_arg, log_bytes!(self.channel_id()));
-               {
-                       let htlc = &mut self.context.pending_inbound_htlcs[pending_idx];
-                       htlc.state = InboundHTLCState::LocalRemoved(InboundHTLCRemovalReason::FailRelay(err_packet.clone()));
-               }
+       /// Creates a new channel from a remote sides' request for one.
+       /// Assumes chain_hash has already been checked and corresponds with what we expect!
+       pub fn new_from_req<ES: Deref, SP: Deref, F: Deref, L: Deref>(
+               fee_estimator: &LowerBoundedFeeEstimator<F>, entropy_source: &ES, signer_provider: &SP,
+               counterparty_node_id: PublicKey, our_supported_features: &ChannelTypeFeatures,
+               their_features: &InitFeatures, msg: &msgs::OpenChannel, user_id: u128, config: &UserConfig,
+               current_chain_height: u32, logger: &L, outbound_scid_alias: u64
+       ) -> Result<Channel<Signer>, ChannelError>
+               where ES::Target: EntropySource,
+                         SP::Target: SignerProvider<Signer = Signer>,
+                         F::Target: FeeEstimator,
+                         L::Target: Logger,
+       {
+               let announced_channel = if (msg.channel_flags & 1) == 1 { true } else { false };
 
-               Ok(Some(msgs::UpdateFailHTLC {
-                       channel_id: self.channel_id(),
-                       htlc_id: htlc_id_arg,
-                       reason: err_packet
-               }))
-       }
+               // First check the channel type is known, failing before we do anything else if we don't
+               // support this channel type.
+               let channel_type = if let Some(channel_type) = &msg.channel_type {
+                       if channel_type.supports_any_optional_bits() {
+                               return Err(ChannelError::Close("Channel Type field contained optional bits - this is not allowed".to_owned()));
+                       }
 
-       // Message handlers:
+                       // We only support the channel types defined by the `ChannelManager` in
+                       // `provided_channel_type_features`. The channel type must always support
+                       // `static_remote_key`.
+                       if !channel_type.requires_static_remote_key() {
+                               return Err(ChannelError::Close("Channel Type was not understood - we require static remote key".to_owned()));
+                       }
+                       // Make sure we support all of the features behind the channel type.
+                       if !channel_type.is_subset(our_supported_features) {
+                               return Err(ChannelError::Close("Channel Type contains unsupported features".to_owned()));
+                       }
+                       if channel_type.requires_scid_privacy() && announced_channel {
+                               return Err(ChannelError::Close("SCID Alias/Privacy Channel Type cannot be set on a public channel".to_owned()));
+                       }
+                       channel_type.clone()
+               } else {
+                       let channel_type = ChannelTypeFeatures::from_init(&their_features);
+                       if channel_type != ChannelTypeFeatures::only_static_remote_key() {
+                               return Err(ChannelError::Close("Only static_remote_key is supported for non-negotiated channel types".to_owned()));
+                       }
+                       channel_type
+               };
+               let opt_anchors = channel_type.supports_anchors_zero_fee_htlc_tx();
 
-       pub fn accept_channel(&mut self, msg: &msgs::AcceptChannel, default_limits: &ChannelHandshakeLimits, their_features: &InitFeatures) -> Result<(), ChannelError> {
-               let peer_limits = if let Some(ref limits) = self.context.inbound_handshake_limits_override { limits } else { default_limits };
+               let channel_keys_id = signer_provider.generate_channel_keys_id(true, msg.funding_satoshis, user_id);
+               let holder_signer = signer_provider.derive_channel_signer(msg.funding_satoshis, channel_keys_id);
+               let pubkeys = holder_signer.pubkeys().clone();
+               let counterparty_pubkeys = ChannelPublicKeys {
+                       funding_pubkey: msg.funding_pubkey,
+                       revocation_basepoint: msg.revocation_basepoint,
+                       payment_point: msg.payment_point,
+                       delayed_payment_basepoint: msg.delayed_payment_basepoint,
+                       htlc_basepoint: msg.htlc_basepoint
+               };
 
-               // Check sanity of message fields:
-               if !self.context.is_outbound() {
-                       return Err(ChannelError::Close("Got an accept_channel message from an inbound peer".to_owned()));
+               if config.channel_handshake_config.our_to_self_delay < BREAKDOWN_TIMEOUT {
+                       return Err(ChannelError::Close(format!("Configured with an unreasonable our_to_self_delay ({}) putting user funds at risks. It must be greater than {}", config.channel_handshake_config.our_to_self_delay, BREAKDOWN_TIMEOUT)));
                }
-               if self.context.channel_state != ChannelState::OurInitSent as u32 {
-                       return Err(ChannelError::Close("Got an accept_channel message at a strange time".to_owned()));
+
+               // Check sanity of message fields:
+               if msg.funding_satoshis > config.channel_handshake_limits.max_funding_satoshis {
+                       return Err(ChannelError::Close(format!("Per our config, funding must be at most {}. It was {}", config.channel_handshake_limits.max_funding_satoshis, msg.funding_satoshis)));
                }
-               if msg.dust_limit_satoshis > 21000000 * 100000000 {
-                       return Err(ChannelError::Close(format!("Peer never wants payout outputs? dust_limit_satoshis was {}", msg.dust_limit_satoshis)));
+               if msg.funding_satoshis >= TOTAL_BITCOIN_SUPPLY_SATOSHIS {
+                       return Err(ChannelError::Close(format!("Funding must be smaller than the total bitcoin supply. It was {}", msg.funding_satoshis)));
                }
-               if msg.channel_reserve_satoshis > self.context.channel_value_satoshis {
-                       return Err(ChannelError::Close(format!("Bogus channel_reserve_satoshis ({}). Must not be greater than ({})", msg.channel_reserve_satoshis, self.context.channel_value_satoshis)));
+               if msg.channel_reserve_satoshis > msg.funding_satoshis {
+                       return Err(ChannelError::Close(format!("Bogus channel_reserve_satoshis ({}). Must be not greater than funding_satoshis: {}", msg.channel_reserve_satoshis, msg.funding_satoshis)));
                }
-               if msg.dust_limit_satoshis > self.context.holder_selected_channel_reserve_satoshis {
-                       return Err(ChannelError::Close(format!("Dust limit ({}) is bigger than our channel reserve ({})", msg.dust_limit_satoshis, self.context.holder_selected_channel_reserve_satoshis)));
+               let full_channel_value_msat = (msg.funding_satoshis - msg.channel_reserve_satoshis) * 1000;
+               if msg.push_msat > full_channel_value_msat {
+                       return Err(ChannelError::Close(format!("push_msat {} was larger than channel amount minus reserve ({})", msg.push_msat, full_channel_value_msat)));
                }
-               if msg.channel_reserve_satoshis > self.context.channel_value_satoshis - self.context.holder_selected_channel_reserve_satoshis {
-                       return Err(ChannelError::Close(format!("Bogus channel_reserve_satoshis ({}). Must not be greater than channel value minus our reserve ({})",
-                               msg.channel_reserve_satoshis, self.context.channel_value_satoshis - self.context.holder_selected_channel_reserve_satoshis)));
+               if msg.dust_limit_satoshis > msg.funding_satoshis {
+                       return Err(ChannelError::Close(format!("dust_limit_satoshis {} was larger than funding_satoshis {}. Peer never wants payout outputs?", msg.dust_limit_satoshis, msg.funding_satoshis)));
                }
-               let full_channel_value_msat = (self.context.channel_value_satoshis - msg.channel_reserve_satoshis) * 1000;
                if msg.htlc_minimum_msat >= full_channel_value_msat {
-                       return Err(ChannelError::Close(format!("Minimum htlc value ({}) is full channel value ({})", msg.htlc_minimum_msat, full_channel_value_msat)));
+                       return Err(ChannelError::Close(format!("Minimum htlc value ({}) was larger than full channel value ({})", msg.htlc_minimum_msat, full_channel_value_msat)));
                }
-               let max_delay_acceptable = u16::min(peer_limits.their_to_self_delay, MAX_LOCAL_BREAKDOWN_TIMEOUT);
-               if msg.to_self_delay > max_delay_acceptable {
-                       return Err(ChannelError::Close(format!("They wanted our payments to be delayed by a needlessly long period. Upper limit: {}. Actual: {}", max_delay_acceptable, msg.to_self_delay)));
+               Channel::<Signer>::check_remote_fee(fee_estimator, msg.feerate_per_kw, None, logger)?;
+
+               let max_counterparty_selected_contest_delay = u16::min(config.channel_handshake_limits.their_to_self_delay, MAX_LOCAL_BREAKDOWN_TIMEOUT);
+               if msg.to_self_delay > max_counterparty_selected_contest_delay {
+                       return Err(ChannelError::Close(format!("They wanted our payments to be delayed by a needlessly long period. Upper limit: {}. Actual: {}", max_counterparty_selected_contest_delay, msg.to_self_delay)));
                }
                if msg.max_accepted_htlcs < 1 {
                        return Err(ChannelError::Close("0 max_accepted_htlcs makes for a useless channel".to_owned()));
@@ -2293,40 +2335,66 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                }
 
                // Now check against optional parameters as set by config...
-               if msg.htlc_minimum_msat > peer_limits.max_htlc_minimum_msat {
-                       return Err(ChannelError::Close(format!("htlc_minimum_msat ({}) is higher than the user specified limit ({})", msg.htlc_minimum_msat, peer_limits.max_htlc_minimum_msat)));
+               if msg.funding_satoshis < config.channel_handshake_limits.min_funding_satoshis {
+                       return Err(ChannelError::Close(format!("Funding satoshis ({}) is less than the user specified limit ({})", msg.funding_satoshis, config.channel_handshake_limits.min_funding_satoshis)));
                }
-               if msg.max_htlc_value_in_flight_msat < peer_limits.min_max_htlc_value_in_flight_msat {
-                       return Err(ChannelError::Close(format!("max_htlc_value_in_flight_msat ({}) is less than the user specified limit ({})", msg.max_htlc_value_in_flight_msat, peer_limits.min_max_htlc_value_in_flight_msat)));
+               if msg.htlc_minimum_msat > config.channel_handshake_limits.max_htlc_minimum_msat {
+                       return Err(ChannelError::Close(format!("htlc_minimum_msat ({}) is higher than the user specified limit ({})", msg.htlc_minimum_msat,  config.channel_handshake_limits.max_htlc_minimum_msat)));
                }
-               if msg.channel_reserve_satoshis > peer_limits.max_channel_reserve_satoshis {
-                       return Err(ChannelError::Close(format!("channel_reserve_satoshis ({}) is higher than the user specified limit ({})", msg.channel_reserve_satoshis, peer_limits.max_channel_reserve_satoshis)));
+               if msg.max_htlc_value_in_flight_msat < config.channel_handshake_limits.min_max_htlc_value_in_flight_msat {
+                       return Err(ChannelError::Close(format!("max_htlc_value_in_flight_msat ({}) is less than the user specified limit ({})", msg.max_htlc_value_in_flight_msat, config.channel_handshake_limits.min_max_htlc_value_in_flight_msat)));
                }
-               if msg.max_accepted_htlcs < peer_limits.min_max_accepted_htlcs {
-                       return Err(ChannelError::Close(format!("max_accepted_htlcs ({}) is less than the user specified limit ({})", msg.max_accepted_htlcs, peer_limits.min_max_accepted_htlcs)));
+               if msg.channel_reserve_satoshis > config.channel_handshake_limits.max_channel_reserve_satoshis {
+                       return Err(ChannelError::Close(format!("channel_reserve_satoshis ({}) is higher than the user specified limit ({})", msg.channel_reserve_satoshis, config.channel_handshake_limits.max_channel_reserve_satoshis)));
+               }
+               if msg.max_accepted_htlcs < config.channel_handshake_limits.min_max_accepted_htlcs {
+                       return Err(ChannelError::Close(format!("max_accepted_htlcs ({}) is less than the user specified limit ({})", msg.max_accepted_htlcs, config.channel_handshake_limits.min_max_accepted_htlcs)));
                }
                if msg.dust_limit_satoshis < MIN_CHAN_DUST_LIMIT_SATOSHIS {
                        return Err(ChannelError::Close(format!("dust_limit_satoshis ({}) is less than the implementation limit ({})", msg.dust_limit_satoshis, MIN_CHAN_DUST_LIMIT_SATOSHIS)));
                }
-               if msg.dust_limit_satoshis > MAX_CHAN_DUST_LIMIT_SATOSHIS {
-                       return Err(ChannelError::Close(format!("dust_limit_satoshis ({}) is greater than the implementation limit ({})", msg.dust_limit_satoshis, MAX_CHAN_DUST_LIMIT_SATOSHIS)));
+               if msg.dust_limit_satoshis >  MAX_CHAN_DUST_LIMIT_SATOSHIS {
+                       return Err(ChannelError::Close(format!("dust_limit_satoshis ({}) is greater than the implementation limit ({})", msg.dust_limit_satoshis, MAX_CHAN_DUST_LIMIT_SATOSHIS)));
+               }
+
+               // Convert things into internal flags and prep our state:
+
+               if config.channel_handshake_limits.force_announced_channel_preference {
+                       if config.channel_handshake_config.announced_channel != announced_channel {
+                               return Err(ChannelError::Close("Peer tried to open channel but their announcement preference is different from ours".to_owned()));
+                       }
+               }
+
+               let holder_selected_channel_reserve_satoshis = get_holder_selected_channel_reserve_satoshis(msg.funding_satoshis, config);
+               if holder_selected_channel_reserve_satoshis < MIN_CHAN_DUST_LIMIT_SATOSHIS {
+                       // Protocol level safety check in place, although it should never happen because
+                       // of `MIN_THEIR_CHAN_RESERVE_SATOSHIS`
+                       return Err(ChannelError::Close(format!("Suitable channel reserve not found. remote_channel_reserve was ({}). dust_limit_satoshis is ({}).", holder_selected_channel_reserve_satoshis, MIN_CHAN_DUST_LIMIT_SATOSHIS)));
+               }
+               if holder_selected_channel_reserve_satoshis * 1000 >= full_channel_value_msat {
+                       return Err(ChannelError::Close(format!("Suitable channel reserve not found. remote_channel_reserve was ({})msats. Channel value is ({} - {})msats.", holder_selected_channel_reserve_satoshis * 1000, full_channel_value_msat, msg.push_msat)));
+               }
+               if msg.channel_reserve_satoshis < MIN_CHAN_DUST_LIMIT_SATOSHIS {
+                       log_debug!(logger, "channel_reserve_satoshis ({}) is smaller than our dust limit ({}). We can broadcast stale states without any risk, implying this channel is very insecure for our counterparty.",
+                               msg.channel_reserve_satoshis, MIN_CHAN_DUST_LIMIT_SATOSHIS);
+               }
+               if holder_selected_channel_reserve_satoshis < msg.dust_limit_satoshis {
+                       return Err(ChannelError::Close(format!("Dust limit ({}) too high for the channel reserve we require the remote to keep ({})", msg.dust_limit_satoshis, holder_selected_channel_reserve_satoshis)));
                }
-               if msg.minimum_depth > peer_limits.max_minimum_depth {
-                       return Err(ChannelError::Close(format!("We consider the minimum depth to be unreasonably large. Expected minimum: ({}). Actual: ({})", peer_limits.max_minimum_depth, msg.minimum_depth)));
+
+               // check if the funder's amount for the initial commitment tx is sufficient
+               // for full fee payment plus a few HTLCs to ensure the channel will be useful.
+               let funders_amount_msat = msg.funding_satoshis * 1000 - msg.push_msat;
+               let commitment_tx_fee = commit_tx_fee_msat(msg.feerate_per_kw, MIN_AFFORDABLE_HTLC_COUNT, opt_anchors) / 1000;
+               if funders_amount_msat / 1000 < commitment_tx_fee {
+                       return Err(ChannelError::Close(format!("Funding amount ({} sats) can't even pay fee for initial commitment transaction fee of {} sats.", funders_amount_msat / 1000, commitment_tx_fee)));
                }
 
-               if let Some(ty) = &msg.channel_type {
-                       if *ty != self.context.channel_type {
-                               return Err(ChannelError::Close("Channel Type in accept_channel didn't match the one sent in open_channel.".to_owned()));
-                       }
-               } else if their_features.supports_channel_type() {
-                       // Assume they've accepted the channel type as they said they understand it.
-               } else {
-                       let channel_type = ChannelTypeFeatures::from_init(&their_features);
-                       if channel_type != ChannelTypeFeatures::only_static_remote_key() {
-                               return Err(ChannelError::Close("Only static_remote_key is supported for non-negotiated channel types".to_owned()));
-                       }
-                       self.context.channel_type = channel_type;
+               let to_remote_satoshis = funders_amount_msat / 1000 - commitment_tx_fee;
+               // While it's reasonable for us to not meet the channel reserve initially (if they don't
+               // want to push much to us), our counterparty should always have more than our reserve.
+               if to_remote_satoshis < holder_selected_channel_reserve_satoshis {
+                       return Err(ChannelError::Close("Insufficient funding amount for initial reserve".to_owned()));
                }
 
                let counterparty_shutdown_scriptpubkey = if their_features.supports_upfront_shutdown_script() {
@@ -2337,7 +2405,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                                                None
                                        } else {
                                                if !script::is_bolt2_compliant(&script, their_features) {
-                                                       return Err(ChannelError::Close(format!("Peer is signaling upfront_shutdown but has provided an unacceptable scriptpubkey format: {}", script)));
+                                                       return Err(ChannelError::Close(format!("Peer is signaling upfront_shutdown but has provided an unacceptable scriptpubkey format: {}", script)))
                                                }
                                                Some(script.clone())
                                        }
@@ -2349,757 +2417,946 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                        }
                } else { None };
 
-               self.context.counterparty_dust_limit_satoshis = msg.dust_limit_satoshis;
-               self.context.counterparty_max_htlc_value_in_flight_msat = cmp::min(msg.max_htlc_value_in_flight_msat, self.context.channel_value_satoshis * 1000);
-               self.context.counterparty_selected_channel_reserve_satoshis = Some(msg.channel_reserve_satoshis);
-               self.context.counterparty_htlc_minimum_msat = msg.htlc_minimum_msat;
-               self.context.counterparty_max_accepted_htlcs = msg.max_accepted_htlcs;
+               let shutdown_scriptpubkey = if config.channel_handshake_config.commit_upfront_shutdown_pubkey {
+                       match signer_provider.get_shutdown_scriptpubkey() {
+                               Ok(scriptpubkey) => Some(scriptpubkey),
+                               Err(_) => return Err(ChannelError::Close("Failed to get upfront shutdown scriptpubkey".to_owned())),
+                       }
+               } else { None };
 
-               if peer_limits.trust_own_funding_0conf {
-                       self.context.minimum_depth = Some(msg.minimum_depth);
-               } else {
-                       self.context.minimum_depth = Some(cmp::max(1, msg.minimum_depth));
+               if let Some(shutdown_scriptpubkey) = &shutdown_scriptpubkey {
+                       if !shutdown_scriptpubkey.is_compatible(&their_features) {
+                               return Err(ChannelError::Close(format!("Provided a scriptpubkey format not accepted by peer: {}", shutdown_scriptpubkey)));
+                       }
                }
 
-               let counterparty_pubkeys = ChannelPublicKeys {
-                       funding_pubkey: msg.funding_pubkey,
-                       revocation_basepoint: msg.revocation_basepoint,
-                       payment_point: msg.payment_point,
-                       delayed_payment_basepoint: msg.delayed_payment_basepoint,
-                       htlc_basepoint: msg.htlc_basepoint
+               let destination_script = match signer_provider.get_destination_script() {
+                       Ok(script) => script,
+                       Err(_) => return Err(ChannelError::Close("Failed to get destination script".to_owned())),
                };
 
-               self.context.channel_transaction_parameters.counterparty_parameters = Some(CounterpartyChannelTransactionParameters {
-                       selected_contest_delay: msg.to_self_delay,
-                       pubkeys: counterparty_pubkeys,
-               });
+               let mut secp_ctx = Secp256k1::new();
+               secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
 
-               self.context.counterparty_cur_commitment_point = Some(msg.first_per_commitment_point);
-               self.context.counterparty_shutdown_scriptpubkey = counterparty_shutdown_scriptpubkey;
+               let chan = Channel {
+                       context: ChannelContext {
+                               user_id,
 
-               self.context.channel_state = ChannelState::OurInitSent as u32 | ChannelState::TheirInitSent as u32;
-               self.context.inbound_handshake_limits_override = None; // We're done enforcing limits on our peer's handshake now.
+                               config: LegacyChannelConfig {
+                                       options: config.channel_config.clone(),
+                                       announced_channel,
+                                       commit_upfront_shutdown_pubkey: config.channel_handshake_config.commit_upfront_shutdown_pubkey,
+                               },
 
-               Ok(())
+                               prev_config: None,
+
+                               inbound_handshake_limits_override: None,
+
+                               temporary_channel_id: Some(msg.temporary_channel_id),
+                               channel_id: msg.temporary_channel_id,
+                               channel_state: (ChannelState::OurInitSent as u32) | (ChannelState::TheirInitSent as u32),
+                               announcement_sigs_state: AnnouncementSigsState::NotSent,
+                               secp_ctx,
+
+                               latest_monitor_update_id: 0,
+
+                               holder_signer,
+                               shutdown_scriptpubkey,
+                               destination_script,
+
+                               cur_holder_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
+                               cur_counterparty_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER,
+                               value_to_self_msat: msg.push_msat,
+
+                               pending_inbound_htlcs: Vec::new(),
+                               pending_outbound_htlcs: Vec::new(),
+                               holding_cell_htlc_updates: Vec::new(),
+                               pending_update_fee: None,
+                               holding_cell_update_fee: None,
+                               next_holder_htlc_id: 0,
+                               next_counterparty_htlc_id: 0,
+                               update_time_counter: 1,
+
+                               resend_order: RAACommitmentOrder::CommitmentFirst,
+
+                               monitor_pending_channel_ready: false,
+                               monitor_pending_revoke_and_ack: false,
+                               monitor_pending_commitment_signed: false,
+                               monitor_pending_forwards: Vec::new(),
+                               monitor_pending_failures: Vec::new(),
+                               monitor_pending_finalized_fulfills: Vec::new(),
+
+                               #[cfg(debug_assertions)]
+                               holder_max_commitment_tx_output: Mutex::new((msg.push_msat, msg.funding_satoshis * 1000 - msg.push_msat)),
+                               #[cfg(debug_assertions)]
+                               counterparty_max_commitment_tx_output: Mutex::new((msg.push_msat, msg.funding_satoshis * 1000 - msg.push_msat)),
+
+                               last_sent_closing_fee: None,
+                               pending_counterparty_closing_signed: None,
+                               closing_fee_limits: None,
+                               target_closing_feerate_sats_per_kw: None,
+
+                               inbound_awaiting_accept: true,
+
+                               funding_tx_confirmed_in: None,
+                               funding_tx_confirmation_height: 0,
+                               short_channel_id: None,
+                               channel_creation_height: current_chain_height,
+
+                               feerate_per_kw: msg.feerate_per_kw,
+                               channel_value_satoshis: msg.funding_satoshis,
+                               counterparty_dust_limit_satoshis: msg.dust_limit_satoshis,
+                               holder_dust_limit_satoshis: MIN_CHAN_DUST_LIMIT_SATOSHIS,
+                               counterparty_max_htlc_value_in_flight_msat: cmp::min(msg.max_htlc_value_in_flight_msat, msg.funding_satoshis * 1000),
+                               holder_max_htlc_value_in_flight_msat: get_holder_max_htlc_value_in_flight_msat(msg.funding_satoshis, &config.channel_handshake_config),
+                               counterparty_selected_channel_reserve_satoshis: Some(msg.channel_reserve_satoshis),
+                               holder_selected_channel_reserve_satoshis,
+                               counterparty_htlc_minimum_msat: msg.htlc_minimum_msat,
+                               holder_htlc_minimum_msat: if config.channel_handshake_config.our_htlc_minimum_msat == 0 { 1 } else { config.channel_handshake_config.our_htlc_minimum_msat },
+                               counterparty_max_accepted_htlcs: msg.max_accepted_htlcs,
+                               holder_max_accepted_htlcs: cmp::min(config.channel_handshake_config.our_max_accepted_htlcs, MAX_HTLCS),
+                               minimum_depth: Some(cmp::max(config.channel_handshake_config.minimum_depth, 1)),
+
+                               counterparty_forwarding_info: None,
+
+                               channel_transaction_parameters: ChannelTransactionParameters {
+                                       holder_pubkeys: pubkeys,
+                                       holder_selected_contest_delay: config.channel_handshake_config.our_to_self_delay,
+                                       is_outbound_from_holder: false,
+                                       counterparty_parameters: Some(CounterpartyChannelTransactionParameters {
+                                               selected_contest_delay: msg.to_self_delay,
+                                               pubkeys: counterparty_pubkeys,
+                                       }),
+                                       funding_outpoint: None,
+                                       opt_anchors: if opt_anchors { Some(()) } else { None },
+                                       opt_non_zero_fee_anchors: None
+                               },
+                               funding_transaction: None,
+
+                               counterparty_cur_commitment_point: Some(msg.first_per_commitment_point),
+                               counterparty_prev_commitment_point: None,
+                               counterparty_node_id,
+
+                               counterparty_shutdown_scriptpubkey,
+
+                               commitment_secrets: CounterpartyCommitmentSecrets::new(),
+
+                               channel_update_status: ChannelUpdateStatus::Enabled,
+                               closing_signed_in_flight: false,
+
+                               announcement_sigs: None,
+
+                               #[cfg(any(test, fuzzing))]
+                               next_local_commitment_tx_fee_info_cached: Mutex::new(None),
+                               #[cfg(any(test, fuzzing))]
+                               next_remote_commitment_tx_fee_info_cached: Mutex::new(None),
+
+                               workaround_lnd_bug_4006: None,
+                               sent_message_awaiting_response: None,
+
+                               latest_inbound_scid_alias: None,
+                               outbound_scid_alias,
+
+                               channel_pending_event_emitted: false,
+                               channel_ready_event_emitted: false,
+
+                               #[cfg(any(test, fuzzing))]
+                               historical_inbound_htlc_fulfills: HashSet::new(),
+
+                               channel_type,
+                               channel_keys_id,
+
+                               pending_monitor_updates: Vec::new(),
+                       }
+               };
+
+               Ok(chan)
        }
 
-       fn funding_created_signature<L: Deref>(&mut self, sig: &Signature, logger: &L) -> Result<(Txid, CommitmentTransaction, Signature), ChannelError> where L::Target: Logger {
-               let funding_script = self.get_funding_redeemscript();
+       #[inline]
+       fn get_closing_scriptpubkey(&self) -> Script {
+               // The shutdown scriptpubkey is set on channel opening when option_upfront_shutdown_script
+               // is signaled. Otherwise, it is set when sending a shutdown message. Calling this method
+               // outside of those situations will fail.
+               self.context.shutdown_scriptpubkey.clone().unwrap().into_inner()
+       }
 
-               let keys = self.build_holder_transaction_keys(self.context.cur_holder_commitment_transaction_number);
-               let initial_commitment_tx = self.build_commitment_transaction(self.context.cur_holder_commitment_transaction_number, &keys, true, false, logger).tx;
-               {
-                       let trusted_tx = initial_commitment_tx.trust();
-                       let initial_commitment_bitcoin_tx = trusted_tx.built_transaction();
-                       let sighash = initial_commitment_bitcoin_tx.get_sighash_all(&funding_script, self.context.channel_value_satoshis);
-                       // They sign the holder commitment transaction...
-                       log_trace!(logger, "Checking funding_created tx signature {} by key {} against tx {} (sighash {}) with redeemscript {} for channel {}.",
-                               log_bytes!(sig.serialize_compact()[..]), log_bytes!(self.counterparty_funding_pubkey().serialize()),
-                               encode::serialize_hex(&initial_commitment_bitcoin_tx.transaction), log_bytes!(sighash[..]),
-                               encode::serialize_hex(&funding_script), log_bytes!(self.channel_id()));
-                       secp_check!(self.context.secp_ctx.verify_ecdsa(&sighash, &sig, self.counterparty_funding_pubkey()), "Invalid funding_created signature from peer".to_owned());
+       #[inline]
+       fn get_closing_transaction_weight(&self, a_scriptpubkey: Option<&Script>, b_scriptpubkey: Option<&Script>) -> u64 {
+               let mut ret =
+               (4 +                                                   // version
+                1 +                                                   // input count
+                36 +                                                  // prevout
+                1 +                                                   // script length (0)
+                4 +                                                   // sequence
+                1 +                                                   // output count
+                4                                                     // lock time
+                )*4 +                                                 // * 4 for non-witness parts
+               2 +                                                    // witness marker and flag
+               1 +                                                    // witness element count
+               4 +                                                    // 4 element lengths (2 sigs, multisig dummy, and witness script)
+               self.context.get_funding_redeemscript().len() as u64 + // funding witness script
+               2*(1 + 71);                                            // two signatures + sighash type flags
+               if let Some(spk) = a_scriptpubkey {
+                       ret += ((8+1) +                                    // output values and script length
+                               spk.len() as u64) * 4;                         // scriptpubkey and witness multiplier
+               }
+               if let Some(spk) = b_scriptpubkey {
+                       ret += ((8+1) +                                    // output values and script length
+                               spk.len() as u64) * 4;                         // scriptpubkey and witness multiplier
                }
+               ret
+       }
 
-               let counterparty_keys = self.build_remote_transaction_keys();
-               let counterparty_initial_commitment_tx = self.build_commitment_transaction(self.context.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, false, logger).tx;
+       #[inline]
+       fn build_closing_transaction(&self, proposed_total_fee_satoshis: u64, skip_remote_output: bool) -> (ClosingTransaction, u64) {
+               assert!(self.context.pending_inbound_htlcs.is_empty());
+               assert!(self.context.pending_outbound_htlcs.is_empty());
+               assert!(self.context.pending_update_fee.is_none());
 
-               let counterparty_trusted_tx = counterparty_initial_commitment_tx.trust();
-               let counterparty_initial_bitcoin_tx = counterparty_trusted_tx.built_transaction();
-               log_trace!(logger, "Initial counterparty tx for channel {} is: txid {} tx {}",
-                       log_bytes!(self.channel_id()), counterparty_initial_bitcoin_tx.txid, encode::serialize_hex(&counterparty_initial_bitcoin_tx.transaction));
+               let mut total_fee_satoshis = proposed_total_fee_satoshis;
+               let mut value_to_holder: i64 = (self.context.value_to_self_msat as i64) / 1000 - if self.context.is_outbound() { total_fee_satoshis as i64 } else { 0 };
+               let mut value_to_counterparty: i64 = ((self.context.channel_value_satoshis * 1000 - self.context.value_to_self_msat) as i64 / 1000) - if self.context.is_outbound() { 0 } else { total_fee_satoshis as i64 };
 
-               let counterparty_signature = self.context.holder_signer.sign_counterparty_commitment(&counterparty_initial_commitment_tx, Vec::new(), &self.context.secp_ctx)
-                               .map_err(|_| ChannelError::Close("Failed to get signatures for new commitment_signed".to_owned()))?.0;
+               if value_to_holder < 0 {
+                       assert!(self.context.is_outbound());
+                       total_fee_satoshis += (-value_to_holder) as u64;
+               } else if value_to_counterparty < 0 {
+                       assert!(!self.context.is_outbound());
+                       total_fee_satoshis += (-value_to_counterparty) as u64;
+               }
+
+               if skip_remote_output || value_to_counterparty as u64 <= self.context.holder_dust_limit_satoshis {
+                       value_to_counterparty = 0;
+               }
+
+               if value_to_holder as u64 <= self.context.holder_dust_limit_satoshis {
+                       value_to_holder = 0;
+               }
+
+               assert!(self.context.shutdown_scriptpubkey.is_some());
+               let holder_shutdown_script = self.get_closing_scriptpubkey();
+               let counterparty_shutdown_script = self.context.counterparty_shutdown_scriptpubkey.clone().unwrap();
+               let funding_outpoint = self.funding_outpoint().into_bitcoin_outpoint();
 
-               // We sign "counterparty" commitment transaction, allowing them to broadcast the tx if they wish.
-               Ok((counterparty_initial_bitcoin_tx.txid, initial_commitment_tx, counterparty_signature))
+               let closing_transaction = ClosingTransaction::new(value_to_holder as u64, value_to_counterparty as u64, holder_shutdown_script, counterparty_shutdown_script, funding_outpoint);
+               (closing_transaction, total_fee_satoshis)
        }
 
-       fn counterparty_funding_pubkey(&self) -> &PublicKey {
-               &self.get_counterparty_pubkeys().funding_pubkey
+       fn funding_outpoint(&self) -> OutPoint {
+               self.context.channel_transaction_parameters.funding_outpoint.unwrap()
        }
 
-       pub fn funding_created<SP: Deref, L: Deref>(
-               &mut self, msg: &msgs::FundingCreated, best_block: BestBlock, signer_provider: &SP, logger: &L
-       ) -> Result<(msgs::FundingSigned, ChannelMonitor<Signer>), ChannelError>
-       where
-               SP::Target: SignerProvider<Signer = Signer>,
-               L::Target: Logger
-       {
-               if self.context.is_outbound() {
-                       return Err(ChannelError::Close("Received funding_created for an outbound channel?".to_owned()));
-               }
-               if self.context.channel_state != (ChannelState::OurInitSent as u32 | ChannelState::TheirInitSent as u32) {
-                       // BOLT 2 says that if we disconnect before we send funding_signed we SHOULD NOT
-                       // remember the channel, so it's safe to just send an error_message here and drop the
-                       // channel.
-                       return Err(ChannelError::Close("Received funding_created after we got the channel!".to_owned()));
-               }
-               if self.context.inbound_awaiting_accept {
-                       return Err(ChannelError::Close("FundingCreated message received before the channel was accepted".to_owned()));
-               }
-               if self.context.commitment_secrets.get_min_seen_secret() != (1 << 48) ||
-                               self.context.cur_counterparty_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER ||
-                               self.context.cur_holder_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER {
-                       panic!("Should not have advanced channel commitment tx numbers prior to funding_created");
+       /// Claims an HTLC while we're disconnected from a peer, dropping the [`ChannelMonitorUpdate`]
+       /// entirely.
+       ///
+       /// The [`ChannelMonitor`] for this channel MUST be updated out-of-band with the preimage
+       /// provided (i.e. without calling [`crate::chain::Watch::update_channel`]).
+       ///
+       /// The HTLC claim will end up in the holding cell (because the caller must ensure the peer is
+       /// disconnected).
+       pub fn claim_htlc_while_disconnected_dropping_mon_update<L: Deref>
+               (&mut self, htlc_id_arg: u64, payment_preimage_arg: PaymentPreimage, logger: &L)
+       where L::Target: Logger {
+               // Assert that we'll add the HTLC claim to the holding cell in `get_update_fulfill_htlc`
+               // (see equivalent if condition there).
+               assert!(self.context.channel_state & (ChannelState::AwaitingRemoteRevoke as u32 | ChannelState::PeerDisconnected as u32 | ChannelState::MonitorUpdateInProgress as u32) != 0);
+               let mon_update_id = self.context.latest_monitor_update_id; // Forget the ChannelMonitor update
+               let fulfill_resp = self.get_update_fulfill_htlc(htlc_id_arg, payment_preimage_arg, logger);
+               self.context.latest_monitor_update_id = mon_update_id;
+               if let UpdateFulfillFetch::NewClaim { msg, .. } = fulfill_resp {
+                       assert!(msg.is_none()); // The HTLC must have ended up in the holding cell.
                }
+       }
 
-               let funding_txo = OutPoint { txid: msg.funding_txid, index: msg.funding_output_index };
-               self.context.channel_transaction_parameters.funding_outpoint = Some(funding_txo);
-               // This is an externally observable change before we finish all our checks.  In particular
-               // funding_created_signature may fail.
-               self.context.holder_signer.provide_channel_parameters(&self.context.channel_transaction_parameters);
-
-               let (counterparty_initial_commitment_txid, initial_commitment_tx, signature) = match self.funding_created_signature(&msg.signature, logger) {
-                       Ok(res) => res,
-                       Err(ChannelError::Close(e)) => {
-                               self.context.channel_transaction_parameters.funding_outpoint = None;
-                               return Err(ChannelError::Close(e));
-                       },
-                       Err(e) => {
-                               // The only error we know how to handle is ChannelError::Close, so we fall over here
-                               // to make sure we don't continue with an inconsistent state.
-                               panic!("unexpected error type from funding_created_signature {:?}", e);
-                       }
-               };
+       fn get_update_fulfill_htlc<L: Deref>(&mut self, htlc_id_arg: u64, payment_preimage_arg: PaymentPreimage, logger: &L) -> UpdateFulfillFetch where L::Target: Logger {
+               // Either ChannelReady got set (which means it won't be unset) or there is no way any
+               // caller thought we could have something claimed (cause we wouldn't have accepted in an
+               // incoming HTLC anyway). If we got to ShutdownComplete, callers aren't allowed to call us,
+               // either.
+               if (self.context.channel_state & (ChannelState::ChannelReady as u32)) != (ChannelState::ChannelReady as u32) {
+                       panic!("Was asked to fulfill an HTLC when channel was not in an operational state");
+               }
+               assert_eq!(self.context.channel_state & ChannelState::ShutdownComplete as u32, 0);
 
-               let holder_commitment_tx = HolderCommitmentTransaction::new(
-                       initial_commitment_tx,
-                       msg.signature,
-                       Vec::new(),
-                       &self.get_holder_pubkeys().funding_pubkey,
-                       self.counterparty_funding_pubkey()
-               );
+               let payment_hash_calc = PaymentHash(Sha256::hash(&payment_preimage_arg.0[..]).into_inner());
 
-               self.context.holder_signer.validate_holder_commitment(&holder_commitment_tx, Vec::new())
-                       .map_err(|_| ChannelError::Close("Failed to validate our commitment".to_owned()))?;
+               // ChannelManager may generate duplicate claims/fails due to HTLC update events from
+               // on-chain ChannelsMonitors during block rescan. Ideally we'd figure out a way to drop
+               // these, but for now we just have to treat them as normal.
 
-               // Now that we're past error-generating stuff, update our local state:
+               let mut pending_idx = core::usize::MAX;
+               let mut htlc_value_msat = 0;
+               for (idx, htlc) in self.context.pending_inbound_htlcs.iter().enumerate() {
+                       if htlc.htlc_id == htlc_id_arg {
+                               assert_eq!(htlc.payment_hash, payment_hash_calc);
+                               match htlc.state {
+                                       InboundHTLCState::Committed => {},
+                                       InboundHTLCState::LocalRemoved(ref reason) => {
+                                               if let &InboundHTLCRemovalReason::Fulfill(_) = reason {
+                                               } else {
+                                                       log_warn!(logger, "Have preimage and want to fulfill HTLC with payment hash {} we already failed against channel {}", log_bytes!(htlc.payment_hash.0), log_bytes!(self.context.channel_id()));
+                                                       debug_assert!(false, "Tried to fulfill an HTLC that was already failed");
+                                               }
+                                               return UpdateFulfillFetch::DuplicateClaim {};
+                                       },
+                                       _ => {
+                                               debug_assert!(false, "Have an inbound HTLC we tried to claim before it was fully committed to");
+                                               // Don't return in release mode here so that we can update channel_monitor
+                                       }
+                               }
+                               pending_idx = idx;
+                               htlc_value_msat = htlc.amount_msat;
+                               break;
+                       }
+               }
+               if pending_idx == core::usize::MAX {
+                       #[cfg(any(test, fuzzing))]
+                       // If we failed to find an HTLC to fulfill, make sure it was previously fulfilled and
+                       // this is simply a duplicate claim, not previously failed and we lost funds.
+                       debug_assert!(self.context.historical_inbound_htlc_fulfills.contains(&htlc_id_arg));
+                       return UpdateFulfillFetch::DuplicateClaim {};
+               }
 
-               let funding_redeemscript = self.get_funding_redeemscript();
-               let funding_txo_script = funding_redeemscript.to_v0_p2wsh();
-               let obscure_factor = get_commitment_transaction_number_obscure_factor(&self.get_holder_pubkeys().payment_point, &self.get_counterparty_pubkeys().payment_point, self.context.is_outbound());
-               let shutdown_script = self.context.shutdown_scriptpubkey.clone().map(|script| script.into_inner());
-               let mut monitor_signer = signer_provider.derive_channel_signer(self.context.channel_value_satoshis, self.context.channel_keys_id);
-               monitor_signer.provide_channel_parameters(&self.context.channel_transaction_parameters);
-               let channel_monitor = ChannelMonitor::new(self.context.secp_ctx.clone(), monitor_signer,
-                                                         shutdown_script, self.get_holder_selected_contest_delay(),
-                                                         &self.context.destination_script, (funding_txo, funding_txo_script.clone()),
-                                                         &self.context.channel_transaction_parameters,
-                                                         funding_redeemscript.clone(), self.context.channel_value_satoshis,
-                                                         obscure_factor,
-                                                         holder_commitment_tx, best_block, self.context.counterparty_node_id);
+               // Now update local state:
+               //
+               // We have to put the payment_preimage in the channel_monitor right away here to ensure we
+               // can claim it even if the channel hits the chain before we see their next commitment.
+               self.context.latest_monitor_update_id += 1;
+               let monitor_update = ChannelMonitorUpdate {
+                       update_id: self.context.latest_monitor_update_id,
+                       updates: vec![ChannelMonitorUpdateStep::PaymentPreimage {
+                               payment_preimage: payment_preimage_arg.clone(),
+                       }],
+               };
 
-               channel_monitor.provide_latest_counterparty_commitment_tx(counterparty_initial_commitment_txid, Vec::new(), self.context.cur_counterparty_commitment_transaction_number, self.context.counterparty_cur_commitment_point.unwrap(), logger);
+               if (self.context.channel_state & (ChannelState::AwaitingRemoteRevoke as u32 | ChannelState::PeerDisconnected as u32 | ChannelState::MonitorUpdateInProgress as u32)) != 0 {
+                       // Note that this condition is the same as the assertion in
+                       // `claim_htlc_while_disconnected_dropping_mon_update` and must match exactly -
+                       // `claim_htlc_while_disconnected_dropping_mon_update` would not work correctly if we
+                       // do not not get into this branch.
+                       for pending_update in self.context.holding_cell_htlc_updates.iter() {
+                               match pending_update {
+                                       &HTLCUpdateAwaitingACK::ClaimHTLC { htlc_id, .. } => {
+                                               if htlc_id_arg == htlc_id {
+                                                       // Make sure we don't leave latest_monitor_update_id incremented here:
+                                                       self.context.latest_monitor_update_id -= 1;
+                                                       #[cfg(any(test, fuzzing))]
+                                                       debug_assert!(self.context.historical_inbound_htlc_fulfills.contains(&htlc_id_arg));
+                                                       return UpdateFulfillFetch::DuplicateClaim {};
+                                               }
+                                       },
+                                       &HTLCUpdateAwaitingACK::FailHTLC { htlc_id, .. } => {
+                                               if htlc_id_arg == htlc_id {
+                                                       log_warn!(logger, "Have preimage and want to fulfill HTLC with pending failure against channel {}", log_bytes!(self.context.channel_id()));
+                                                       // TODO: We may actually be able to switch to a fulfill here, though its
+                                                       // rare enough it may not be worth the complexity burden.
+                                                       debug_assert!(false, "Tried to fulfill an HTLC that was already failed");
+                                                       return UpdateFulfillFetch::NewClaim { monitor_update, htlc_value_msat, msg: None };
+                                               }
+                                       },
+                                       _ => {}
+                               }
+                       }
+                       log_trace!(logger, "Adding HTLC claim to holding_cell in channel {}! Current state: {}", log_bytes!(self.context.channel_id()), self.context.channel_state);
+                       self.context.holding_cell_htlc_updates.push(HTLCUpdateAwaitingACK::ClaimHTLC {
+                               payment_preimage: payment_preimage_arg, htlc_id: htlc_id_arg,
+                       });
+                       #[cfg(any(test, fuzzing))]
+                       self.context.historical_inbound_htlc_fulfills.insert(htlc_id_arg);
+                       return UpdateFulfillFetch::NewClaim { monitor_update, htlc_value_msat, msg: None };
+               }
+               #[cfg(any(test, fuzzing))]
+               self.context.historical_inbound_htlc_fulfills.insert(htlc_id_arg);
 
-               self.context.channel_state = ChannelState::FundingSent as u32;
-               self.context.channel_id = funding_txo.to_channel_id();
-               self.context.cur_counterparty_commitment_transaction_number -= 1;
-               self.context.cur_holder_commitment_transaction_number -= 1;
+               {
+                       let htlc = &mut self.context.pending_inbound_htlcs[pending_idx];
+                       if let InboundHTLCState::Committed = htlc.state {
+                       } else {
+                               debug_assert!(false, "Have an inbound HTLC we tried to claim before it was fully committed to");
+                               return UpdateFulfillFetch::NewClaim { monitor_update, htlc_value_msat, msg: None };
+                       }
+                       log_trace!(logger, "Upgrading HTLC {} to LocalRemoved with a Fulfill in channel {}!", log_bytes!(htlc.payment_hash.0), log_bytes!(self.context.channel_id));
+                       htlc.state = InboundHTLCState::LocalRemoved(InboundHTLCRemovalReason::Fulfill(payment_preimage_arg.clone()));
+               }
 
-               log_info!(logger, "Generated funding_signed for peer for channel {}", log_bytes!(self.channel_id()));
+               UpdateFulfillFetch::NewClaim {
+                       monitor_update,
+                       htlc_value_msat,
+                       msg: Some(msgs::UpdateFulfillHTLC {
+                               channel_id: self.context.channel_id(),
+                               htlc_id: htlc_id_arg,
+                               payment_preimage: payment_preimage_arg,
+                       }),
+               }
+       }
 
-               let need_channel_ready = self.check_get_channel_ready(0).is_some();
-               self.monitor_updating_paused(false, false, need_channel_ready, Vec::new(), Vec::new(), Vec::new());
+       pub fn get_update_fulfill_htlc_and_commit<L: Deref>(&mut self, htlc_id: u64, payment_preimage: PaymentPreimage, logger: &L) -> UpdateFulfillCommitFetch where L::Target: Logger {
+               let release_cs_monitor = self.context.pending_monitor_updates.iter().all(|upd| !upd.blocked);
+               match self.get_update_fulfill_htlc(htlc_id, payment_preimage, logger) {
+                       UpdateFulfillFetch::NewClaim { mut monitor_update, htlc_value_msat, msg } => {
+                               // Even if we aren't supposed to let new monitor updates with commitment state
+                               // updates run, we still need to push the preimage ChannelMonitorUpdateStep no
+                               // matter what. Sadly, to push a new monitor update which flies before others
+                               // already queued, we have to insert it into the pending queue and update the
+                               // update_ids of all the following monitors.
+                               let unblocked_update_pos = if release_cs_monitor && msg.is_some() {
+                                       let mut additional_update = self.build_commitment_no_status_check(logger);
+                                       // build_commitment_no_status_check may bump latest_monitor_id but we want them
+                                       // to be strictly increasing by one, so decrement it here.
+                                       self.context.latest_monitor_update_id = monitor_update.update_id;
+                                       monitor_update.updates.append(&mut additional_update.updates);
+                                       self.context.pending_monitor_updates.push(PendingChannelMonitorUpdate {
+                                               update: monitor_update, blocked: false,
+                                       });
+                                       self.context.pending_monitor_updates.len() - 1
+                               } else {
+                                       let insert_pos = self.context.pending_monitor_updates.iter().position(|upd| upd.blocked)
+                                               .unwrap_or(self.context.pending_monitor_updates.len());
+                                       let new_mon_id = self.context.pending_monitor_updates.get(insert_pos)
+                                               .map(|upd| upd.update.update_id).unwrap_or(monitor_update.update_id);
+                                       monitor_update.update_id = new_mon_id;
+                                       self.context.pending_monitor_updates.insert(insert_pos, PendingChannelMonitorUpdate {
+                                               update: monitor_update, blocked: false,
+                                       });
+                                       for held_update in self.context.pending_monitor_updates.iter_mut().skip(insert_pos + 1) {
+                                               held_update.update.update_id += 1;
+                                       }
+                                       if msg.is_some() {
+                                               debug_assert!(false, "If there is a pending blocked monitor we should have MonitorUpdateInProgress set");
+                                               let update = self.build_commitment_no_status_check(logger);
+                                               self.context.pending_monitor_updates.push(PendingChannelMonitorUpdate {
+                                                       update, blocked: true,
+                                               });
+                                       }
+                                       insert_pos
+                               };
+                               self.monitor_updating_paused(false, msg.is_some(), false, Vec::new(), Vec::new(), Vec::new());
+                               UpdateFulfillCommitFetch::NewClaim {
+                                       monitor_update: &self.context.pending_monitor_updates.get(unblocked_update_pos)
+                                               .expect("We just pushed the monitor update").update,
+                                       htlc_value_msat,
+                               }
+                       },
+                       UpdateFulfillFetch::DuplicateClaim {} => UpdateFulfillCommitFetch::DuplicateClaim {},
+               }
+       }
 
-               Ok((msgs::FundingSigned {
-                       channel_id: self.context.channel_id,
-                       signature,
-                       #[cfg(taproot)]
-                       partial_signature_with_nonce: None,
-               }, channel_monitor))
+       /// We can only have one resolution per HTLC. In some cases around reconnect, we may fulfill
+       /// an HTLC more than once or fulfill once and then attempt to fail after reconnect. We cannot,
+       /// however, fail more than once as we wait for an upstream failure to be irrevocably committed
+       /// before we fail backwards.
+       ///
+       /// If we do fail twice, we `debug_assert!(false)` and return `Ok(None)`. Thus, this will always
+       /// return `Ok(_)` if preconditions are met. In any case, `Err`s will only be
+       /// [`ChannelError::Ignore`].
+       pub fn queue_fail_htlc<L: Deref>(&mut self, htlc_id_arg: u64, err_packet: msgs::OnionErrorPacket, logger: &L)
+       -> Result<(), ChannelError> where L::Target: Logger {
+               self.fail_htlc(htlc_id_arg, err_packet, true, logger)
+                       .map(|msg_opt| assert!(msg_opt.is_none(), "We forced holding cell?"))
        }
 
-       /// Handles a funding_signed message from the remote end.
-       /// If this call is successful, broadcast the funding transaction (and not before!)
-       pub fn funding_signed<SP: Deref, L: Deref>(
-               &mut self, msg: &msgs::FundingSigned, best_block: BestBlock, signer_provider: &SP, logger: &L
-       ) -> Result<ChannelMonitor<Signer>, ChannelError>
-       where
-               SP::Target: SignerProvider<Signer = Signer>,
-               L::Target: Logger
-       {
-               if !self.context.is_outbound() {
-                       return Err(ChannelError::Close("Received funding_signed for an inbound channel?".to_owned()));
-               }
-               if self.context.channel_state & !(ChannelState::MonitorUpdateInProgress as u32) != ChannelState::FundingCreated as u32 {
-                       return Err(ChannelError::Close("Received funding_signed in strange state!".to_owned()));
-               }
-               if self.context.commitment_secrets.get_min_seen_secret() != (1 << 48) ||
-                               self.context.cur_counterparty_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER ||
-                               self.context.cur_holder_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER {
-                       panic!("Should not have advanced channel commitment tx numbers prior to funding_created");
+       /// We can only have one resolution per HTLC. In some cases around reconnect, we may fulfill
+       /// an HTLC more than once or fulfill once and then attempt to fail after reconnect. We cannot,
+       /// however, fail more than once as we wait for an upstream failure to be irrevocably committed
+       /// before we fail backwards.
+       ///
+       /// If we do fail twice, we `debug_assert!(false)` and return `Ok(None)`. Thus, this will always
+       /// return `Ok(_)` if preconditions are met. In any case, `Err`s will only be
+       /// [`ChannelError::Ignore`].
+       fn fail_htlc<L: Deref>(&mut self, htlc_id_arg: u64, err_packet: msgs::OnionErrorPacket, mut force_holding_cell: bool, logger: &L)
+       -> Result<Option<msgs::UpdateFailHTLC>, ChannelError> where L::Target: Logger {
+               if (self.context.channel_state & (ChannelState::ChannelReady as u32)) != (ChannelState::ChannelReady as u32) {
+                       panic!("Was asked to fail an HTLC when channel was not in an operational state");
                }
+               assert_eq!(self.context.channel_state & ChannelState::ShutdownComplete as u32, 0);
 
-               let funding_script = self.get_funding_redeemscript();
-
-               let counterparty_keys = self.build_remote_transaction_keys();
-               let counterparty_initial_commitment_tx = self.build_commitment_transaction(self.context.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, false, logger).tx;
-               let counterparty_trusted_tx = counterparty_initial_commitment_tx.trust();
-               let counterparty_initial_bitcoin_tx = counterparty_trusted_tx.built_transaction();
-
-               log_trace!(logger, "Initial counterparty tx for channel {} is: txid {} tx {}",
-                       log_bytes!(self.channel_id()), counterparty_initial_bitcoin_tx.txid, encode::serialize_hex(&counterparty_initial_bitcoin_tx.transaction));
+               // ChannelManager may generate duplicate claims/fails due to HTLC update events from
+               // on-chain ChannelsMonitors during block rescan. Ideally we'd figure out a way to drop
+               // these, but for now we just have to treat them as normal.
 
-               let holder_signer = self.build_holder_transaction_keys(self.context.cur_holder_commitment_transaction_number);
-               let initial_commitment_tx = self.build_commitment_transaction(self.context.cur_holder_commitment_transaction_number, &holder_signer, true, false, logger).tx;
-               {
-                       let trusted_tx = initial_commitment_tx.trust();
-                       let initial_commitment_bitcoin_tx = trusted_tx.built_transaction();
-                       let sighash = initial_commitment_bitcoin_tx.get_sighash_all(&funding_script, self.context.channel_value_satoshis);
-                       // They sign our commitment transaction, allowing us to broadcast the tx if we wish.
-                       if let Err(_) = self.context.secp_ctx.verify_ecdsa(&sighash, &msg.signature, &self.get_counterparty_pubkeys().funding_pubkey) {
-                               return Err(ChannelError::Close("Invalid funding_signed signature from peer".to_owned()));
+               let mut pending_idx = core::usize::MAX;
+               for (idx, htlc) in self.context.pending_inbound_htlcs.iter().enumerate() {
+                       if htlc.htlc_id == htlc_id_arg {
+                               match htlc.state {
+                                       InboundHTLCState::Committed => {},
+                                       InboundHTLCState::LocalRemoved(ref reason) => {
+                                               if let &InboundHTLCRemovalReason::Fulfill(_) = reason {
+                                               } else {
+                                                       debug_assert!(false, "Tried to fail an HTLC that was already failed");
+                                               }
+                                               return Ok(None);
+                                       },
+                                       _ => {
+                                               debug_assert!(false, "Have an inbound HTLC we tried to claim before it was fully committed to");
+                                               return Err(ChannelError::Ignore(format!("Unable to find a pending HTLC which matched the given HTLC ID ({})", htlc.htlc_id)));
+                                       }
+                               }
+                               pending_idx = idx;
                        }
                }
+               if pending_idx == core::usize::MAX {
+                       #[cfg(any(test, fuzzing))]
+                       // If we failed to find an HTLC to fail, make sure it was previously fulfilled and this
+                       // is simply a duplicate fail, not previously failed and we failed-back too early.
+                       debug_assert!(self.context.historical_inbound_htlc_fulfills.contains(&htlc_id_arg));
+                       return Ok(None);
+               }
 
-               let holder_commitment_tx = HolderCommitmentTransaction::new(
-                       initial_commitment_tx,
-                       msg.signature,
-                       Vec::new(),
-                       &self.get_holder_pubkeys().funding_pubkey,
-                       self.counterparty_funding_pubkey()
-               );
-
-               self.context.holder_signer.validate_holder_commitment(&holder_commitment_tx, Vec::new())
-                       .map_err(|_| ChannelError::Close("Failed to validate our commitment".to_owned()))?;
-
+               if (self.context.channel_state & (ChannelState::AwaitingRemoteRevoke as u32 | ChannelState::PeerDisconnected as u32 | ChannelState::MonitorUpdateInProgress as u32)) != 0 {
+                       debug_assert!(force_holding_cell, "!force_holding_cell is only called when emptying the holding cell, so we shouldn't end up back in it!");
+                       force_holding_cell = true;
+               }
 
-               let funding_redeemscript = self.get_funding_redeemscript();
-               let funding_txo = self.get_funding_txo().unwrap();
-               let funding_txo_script = funding_redeemscript.to_v0_p2wsh();
-               let obscure_factor = get_commitment_transaction_number_obscure_factor(&self.get_holder_pubkeys().payment_point, &self.get_counterparty_pubkeys().payment_point, self.context.is_outbound());
-               let shutdown_script = self.context.shutdown_scriptpubkey.clone().map(|script| script.into_inner());
-               let mut monitor_signer = signer_provider.derive_channel_signer(self.context.channel_value_satoshis, self.context.channel_keys_id);
-               monitor_signer.provide_channel_parameters(&self.context.channel_transaction_parameters);
-               let channel_monitor = ChannelMonitor::new(self.context.secp_ctx.clone(), monitor_signer,
-                                                         shutdown_script, self.get_holder_selected_contest_delay(),
-                                                         &self.context.destination_script, (funding_txo, funding_txo_script),
-                                                         &self.context.channel_transaction_parameters,
-                                                         funding_redeemscript.clone(), self.context.channel_value_satoshis,
-                                                         obscure_factor,
-                                                         holder_commitment_tx, best_block, self.context.counterparty_node_id);
+               // Now update local state:
+               if force_holding_cell {
+                       for pending_update in self.context.holding_cell_htlc_updates.iter() {
+                               match pending_update {
+                                       &HTLCUpdateAwaitingACK::ClaimHTLC { htlc_id, .. } => {
+                                               if htlc_id_arg == htlc_id {
+                                                       #[cfg(any(test, fuzzing))]
+                                                       debug_assert!(self.context.historical_inbound_htlc_fulfills.contains(&htlc_id_arg));
+                                                       return Ok(None);
+                                               }
+                                       },
+                                       &HTLCUpdateAwaitingACK::FailHTLC { htlc_id, .. } => {
+                                               if htlc_id_arg == htlc_id {
+                                                       debug_assert!(false, "Tried to fail an HTLC that was already failed");
+                                                       return Err(ChannelError::Ignore("Unable to find a pending HTLC which matched the given HTLC ID".to_owned()));
+                                               }
+                                       },
+                                       _ => {}
+                               }
+                       }
+                       log_trace!(logger, "Placing failure for HTLC ID {} in holding cell in channel {}.", htlc_id_arg, log_bytes!(self.context.channel_id()));
+                       self.context.holding_cell_htlc_updates.push(HTLCUpdateAwaitingACK::FailHTLC {
+                               htlc_id: htlc_id_arg,
+                               err_packet,
+                       });
+                       return Ok(None);
+               }
 
-               channel_monitor.provide_latest_counterparty_commitment_tx(counterparty_initial_bitcoin_tx.txid, Vec::new(), self.context.cur_counterparty_commitment_transaction_number, self.context.counterparty_cur_commitment_point.unwrap(), logger);
+               log_trace!(logger, "Failing HTLC ID {} back with a update_fail_htlc message in channel {}.", htlc_id_arg, log_bytes!(self.context.channel_id()));
+               {
+                       let htlc = &mut self.context.pending_inbound_htlcs[pending_idx];
+                       htlc.state = InboundHTLCState::LocalRemoved(InboundHTLCRemovalReason::FailRelay(err_packet.clone()));
+               }
 
-               assert_eq!(self.context.channel_state & (ChannelState::MonitorUpdateInProgress as u32), 0); // We have no had any monitor(s) yet to fail update!
-               self.context.channel_state = ChannelState::FundingSent as u32;
-               self.context.cur_holder_commitment_transaction_number -= 1;
-               self.context.cur_counterparty_commitment_transaction_number -= 1;
+               Ok(Some(msgs::UpdateFailHTLC {
+                       channel_id: self.context.channel_id(),
+                       htlc_id: htlc_id_arg,
+                       reason: err_packet
+               }))
+       }
 
-               log_info!(logger, "Received funding_signed from peer for channel {}", log_bytes!(self.channel_id()));
+       // Message handlers:
 
-               let need_channel_ready = self.check_get_channel_ready(0).is_some();
-               self.monitor_updating_paused(false, false, need_channel_ready, Vec::new(), Vec::new(), Vec::new());
-               Ok(channel_monitor)
-       }
+       pub fn accept_channel(&mut self, msg: &msgs::AcceptChannel, default_limits: &ChannelHandshakeLimits, their_features: &InitFeatures) -> Result<(), ChannelError> {
+               let peer_limits = if let Some(ref limits) = self.context.inbound_handshake_limits_override { limits } else { default_limits };
 
-       /// Handles a channel_ready message from our peer. If we've already sent our channel_ready
-       /// and the channel is now usable (and public), this may generate an announcement_signatures to
-       /// reply with.
-       pub fn channel_ready<NS: Deref, L: Deref>(
-               &mut self, msg: &msgs::ChannelReady, node_signer: &NS, genesis_block_hash: BlockHash,
-               user_config: &UserConfig, best_block: &BestBlock, logger: &L
-       ) -> Result<Option<msgs::AnnouncementSignatures>, ChannelError>
-       where
-               NS::Target: NodeSigner,
-               L::Target: Logger
-       {
-               if self.context.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
-                       self.context.workaround_lnd_bug_4006 = Some(msg.clone());
-                       return Err(ChannelError::Ignore("Peer sent channel_ready when we needed a channel_reestablish. The peer is likely lnd, see https://github.com/lightningnetwork/lnd/issues/4006".to_owned()));
+               // Check sanity of message fields:
+               if !self.context.is_outbound() {
+                       return Err(ChannelError::Close("Got an accept_channel message from an inbound peer".to_owned()));
                }
-
-               if let Some(scid_alias) = msg.short_channel_id_alias {
-                       if Some(scid_alias) != self.context.short_channel_id {
-                               // The scid alias provided can be used to route payments *from* our counterparty,
-                               // i.e. can be used for inbound payments and provided in invoices, but is not used
-                               // when routing outbound payments.
-                               self.context.latest_inbound_scid_alias = Some(scid_alias);
-                       }
+               if self.context.channel_state != ChannelState::OurInitSent as u32 {
+                       return Err(ChannelError::Close("Got an accept_channel message at a strange time".to_owned()));
+               }
+               if msg.dust_limit_satoshis > 21000000 * 100000000 {
+                       return Err(ChannelError::Close(format!("Peer never wants payout outputs? dust_limit_satoshis was {}", msg.dust_limit_satoshis)));
+               }
+               if msg.channel_reserve_satoshis > self.context.channel_value_satoshis {
+                       return Err(ChannelError::Close(format!("Bogus channel_reserve_satoshis ({}). Must not be greater than ({})", msg.channel_reserve_satoshis, self.context.channel_value_satoshis)));
+               }
+               if msg.dust_limit_satoshis > self.context.holder_selected_channel_reserve_satoshis {
+                       return Err(ChannelError::Close(format!("Dust limit ({}) is bigger than our channel reserve ({})", msg.dust_limit_satoshis, self.context.holder_selected_channel_reserve_satoshis)));
+               }
+               if msg.channel_reserve_satoshis > self.context.channel_value_satoshis - self.context.holder_selected_channel_reserve_satoshis {
+                       return Err(ChannelError::Close(format!("Bogus channel_reserve_satoshis ({}). Must not be greater than channel value minus our reserve ({})",
+                               msg.channel_reserve_satoshis, self.context.channel_value_satoshis - self.context.holder_selected_channel_reserve_satoshis)));
+               }
+               let full_channel_value_msat = (self.context.channel_value_satoshis - msg.channel_reserve_satoshis) * 1000;
+               if msg.htlc_minimum_msat >= full_channel_value_msat {
+                       return Err(ChannelError::Close(format!("Minimum htlc value ({}) is full channel value ({})", msg.htlc_minimum_msat, full_channel_value_msat)));
+               }
+               let max_delay_acceptable = u16::min(peer_limits.their_to_self_delay, MAX_LOCAL_BREAKDOWN_TIMEOUT);
+               if msg.to_self_delay > max_delay_acceptable {
+                       return Err(ChannelError::Close(format!("They wanted our payments to be delayed by a needlessly long period. Upper limit: {}. Actual: {}", max_delay_acceptable, msg.to_self_delay)));
+               }
+               if msg.max_accepted_htlcs < 1 {
+                       return Err(ChannelError::Close("0 max_accepted_htlcs makes for a useless channel".to_owned()));
+               }
+               if msg.max_accepted_htlcs > MAX_HTLCS {
+                       return Err(ChannelError::Close(format!("max_accepted_htlcs was {}. It must not be larger than {}", msg.max_accepted_htlcs, MAX_HTLCS)));
                }
 
-               let non_shutdown_state = self.context.channel_state & (!MULTI_STATE_FLAGS);
-
-               if non_shutdown_state == ChannelState::FundingSent as u32 {
-                       self.context.channel_state |= ChannelState::TheirChannelReady as u32;
-               } else if non_shutdown_state == (ChannelState::FundingSent as u32 | ChannelState::OurChannelReady as u32) {
-                       self.context.channel_state = ChannelState::ChannelReady as u32 | (self.context.channel_state & MULTI_STATE_FLAGS);
-                       self.context.update_time_counter += 1;
-               } else if self.context.channel_state & (ChannelState::ChannelReady as u32) != 0 ||
-                       // If we reconnected before sending our `channel_ready` they may still resend theirs:
-                       (self.context.channel_state & (ChannelState::FundingSent as u32 | ChannelState::TheirChannelReady as u32) ==
-                                             (ChannelState::FundingSent as u32 | ChannelState::TheirChannelReady as u32))
-               {
-                       // They probably disconnected/reconnected and re-sent the channel_ready, which is
-                       // required, or they're sending a fresh SCID alias.
-                       let expected_point =
-                               if self.context.cur_counterparty_commitment_transaction_number == INITIAL_COMMITMENT_NUMBER - 1 {
-                                       // If they haven't ever sent an updated point, the point they send should match
-                                       // the current one.
-                                       self.context.counterparty_cur_commitment_point
-                               } else if self.context.cur_counterparty_commitment_transaction_number == INITIAL_COMMITMENT_NUMBER - 2 {
-                                       // If we've advanced the commitment number once, the second commitment point is
-                                       // at `counterparty_prev_commitment_point`, which is not yet revoked.
-                                       debug_assert!(self.context.counterparty_prev_commitment_point.is_some());
-                                       self.context.counterparty_prev_commitment_point
-                               } else {
-                                       // If they have sent updated points, channel_ready is always supposed to match
-                                       // their "first" point, which we re-derive here.
-                                       Some(PublicKey::from_secret_key(&self.context.secp_ctx, &SecretKey::from_slice(
-                                                       &self.context.commitment_secrets.get_secret(INITIAL_COMMITMENT_NUMBER - 1).expect("We should have all prev secrets available")
-                                               ).expect("We already advanced, so previous secret keys should have been validated already")))
-                               };
-                       if expected_point != Some(msg.next_per_commitment_point) {
-                               return Err(ChannelError::Close("Peer sent a reconnect channel_ready with a different point".to_owned()));
+               // Now check against optional parameters as set by config...
+               if msg.htlc_minimum_msat > peer_limits.max_htlc_minimum_msat {
+                       return Err(ChannelError::Close(format!("htlc_minimum_msat ({}) is higher than the user specified limit ({})", msg.htlc_minimum_msat, peer_limits.max_htlc_minimum_msat)));
+               }
+               if msg.max_htlc_value_in_flight_msat < peer_limits.min_max_htlc_value_in_flight_msat {
+                       return Err(ChannelError::Close(format!("max_htlc_value_in_flight_msat ({}) is less than the user specified limit ({})", msg.max_htlc_value_in_flight_msat, peer_limits.min_max_htlc_value_in_flight_msat)));
+               }
+               if msg.channel_reserve_satoshis > peer_limits.max_channel_reserve_satoshis {
+                       return Err(ChannelError::Close(format!("channel_reserve_satoshis ({}) is higher than the user specified limit ({})", msg.channel_reserve_satoshis, peer_limits.max_channel_reserve_satoshis)));
+               }
+               if msg.max_accepted_htlcs < peer_limits.min_max_accepted_htlcs {
+                       return Err(ChannelError::Close(format!("max_accepted_htlcs ({}) is less than the user specified limit ({})", msg.max_accepted_htlcs, peer_limits.min_max_accepted_htlcs)));
+               }
+               if msg.dust_limit_satoshis < MIN_CHAN_DUST_LIMIT_SATOSHIS {
+                       return Err(ChannelError::Close(format!("dust_limit_satoshis ({}) is less than the implementation limit ({})", msg.dust_limit_satoshis, MIN_CHAN_DUST_LIMIT_SATOSHIS)));
+               }
+               if msg.dust_limit_satoshis > MAX_CHAN_DUST_LIMIT_SATOSHIS {
+                       return Err(ChannelError::Close(format!("dust_limit_satoshis ({}) is greater than the implementation limit ({})", msg.dust_limit_satoshis, MAX_CHAN_DUST_LIMIT_SATOSHIS)));
+               }
+               if msg.minimum_depth > peer_limits.max_minimum_depth {
+                       return Err(ChannelError::Close(format!("We consider the minimum depth to be unreasonably large. Expected minimum: ({}). Actual: ({})", peer_limits.max_minimum_depth, msg.minimum_depth)));
+               }
+
+               if let Some(ty) = &msg.channel_type {
+                       if *ty != self.context.channel_type {
+                               return Err(ChannelError::Close("Channel Type in accept_channel didn't match the one sent in open_channel.".to_owned()));
                        }
-                       return Ok(None);
+               } else if their_features.supports_channel_type() {
+                       // Assume they've accepted the channel type as they said they understand it.
                } else {
-                       return Err(ChannelError::Close("Peer sent a channel_ready at a strange time".to_owned()));
+                       let channel_type = ChannelTypeFeatures::from_init(&their_features);
+                       if channel_type != ChannelTypeFeatures::only_static_remote_key() {
+                               return Err(ChannelError::Close("Only static_remote_key is supported for non-negotiated channel types".to_owned()));
+                       }
+                       self.context.channel_type = channel_type;
                }
 
-               self.context.counterparty_prev_commitment_point = self.context.counterparty_cur_commitment_point;
-               self.context.counterparty_cur_commitment_point = Some(msg.next_per_commitment_point);
-
-               log_info!(logger, "Received channel_ready from peer for channel {}", log_bytes!(self.channel_id()));
+               let counterparty_shutdown_scriptpubkey = if their_features.supports_upfront_shutdown_script() {
+                       match &msg.shutdown_scriptpubkey {
+                               &Some(ref script) => {
+                                       // Peer is signaling upfront_shutdown and has opt-out with a 0-length script. We don't enforce anything
+                                       if script.len() == 0 {
+                                               None
+                                       } else {
+                                               if !script::is_bolt2_compliant(&script, their_features) {
+                                                       return Err(ChannelError::Close(format!("Peer is signaling upfront_shutdown but has provided an unacceptable scriptpubkey format: {}", script)));
+                                               }
+                                               Some(script.clone())
+                                       }
+                               },
+                               // Peer is signaling upfront shutdown but don't opt-out with correct mechanism (a.k.a 0-length script). Peer looks buggy, we fail the channel
+                               &None => {
+                                       return Err(ChannelError::Close("Peer is signaling upfront_shutdown but we don't get any script. Use 0-length script to opt-out".to_owned()));
+                               }
+                       }
+               } else { None };
 
-               Ok(self.get_announcement_sigs(node_signer, genesis_block_hash, user_config, best_block.height(), logger))
-       }
+               self.context.counterparty_dust_limit_satoshis = msg.dust_limit_satoshis;
+               self.context.counterparty_max_htlc_value_in_flight_msat = cmp::min(msg.max_htlc_value_in_flight_msat, self.context.channel_value_satoshis * 1000);
+               self.context.counterparty_selected_channel_reserve_satoshis = Some(msg.channel_reserve_satoshis);
+               self.context.counterparty_htlc_minimum_msat = msg.htlc_minimum_msat;
+               self.context.counterparty_max_accepted_htlcs = msg.max_accepted_htlcs;
 
-       /// Returns transaction if there is pending funding transaction that is yet to broadcast
-       pub fn unbroadcasted_funding(&self) -> Option<Transaction> {
-               if self.context.channel_state & (ChannelState::FundingCreated as u32) != 0 {
-                       self.context.funding_transaction.clone()
+               if peer_limits.trust_own_funding_0conf {
+                       self.context.minimum_depth = Some(msg.minimum_depth);
                } else {
-                       None
+                       self.context.minimum_depth = Some(cmp::max(1, msg.minimum_depth));
                }
-       }
 
-       /// Returns a HTLCStats about inbound pending htlcs
-       fn get_inbound_pending_htlc_stats(&self, outbound_feerate_update: Option<u32>) -> HTLCStats {
-               let mut stats = HTLCStats {
-                       pending_htlcs: self.context.pending_inbound_htlcs.len() as u32,
-                       pending_htlcs_value_msat: 0,
-                       on_counterparty_tx_dust_exposure_msat: 0,
-                       on_holder_tx_dust_exposure_msat: 0,
-                       holding_cell_msat: 0,
-                       on_holder_tx_holding_cell_htlcs_count: 0,
+               let counterparty_pubkeys = ChannelPublicKeys {
+                       funding_pubkey: msg.funding_pubkey,
+                       revocation_basepoint: msg.revocation_basepoint,
+                       payment_point: msg.payment_point,
+                       delayed_payment_basepoint: msg.delayed_payment_basepoint,
+                       htlc_basepoint: msg.htlc_basepoint
                };
 
-               let (htlc_timeout_dust_limit, htlc_success_dust_limit) = if self.context.opt_anchors() {
-                       (0, 0)
-               } else {
-                       let dust_buffer_feerate = self.get_dust_buffer_feerate(outbound_feerate_update) as u64;
-                       (dust_buffer_feerate * htlc_timeout_tx_weight(false) / 1000,
-                               dust_buffer_feerate * htlc_success_tx_weight(false) / 1000)
-               };
-               let counterparty_dust_limit_timeout_sat = htlc_timeout_dust_limit + self.context.counterparty_dust_limit_satoshis;
-               let holder_dust_limit_success_sat = htlc_success_dust_limit + self.context.holder_dust_limit_satoshis;
-               for ref htlc in self.context.pending_inbound_htlcs.iter() {
-                       stats.pending_htlcs_value_msat += htlc.amount_msat;
-                       if htlc.amount_msat / 1000 < counterparty_dust_limit_timeout_sat {
-                               stats.on_counterparty_tx_dust_exposure_msat += htlc.amount_msat;
-                       }
-                       if htlc.amount_msat / 1000 < holder_dust_limit_success_sat {
-                               stats.on_holder_tx_dust_exposure_msat += htlc.amount_msat;
-                       }
-               }
-               stats
-       }
+               self.context.channel_transaction_parameters.counterparty_parameters = Some(CounterpartyChannelTransactionParameters {
+                       selected_contest_delay: msg.to_self_delay,
+                       pubkeys: counterparty_pubkeys,
+               });
 
-       /// Returns a HTLCStats about pending outbound htlcs, *including* pending adds in our holding cell.
-       fn get_outbound_pending_htlc_stats(&self, outbound_feerate_update: Option<u32>) -> HTLCStats {
-               let mut stats = HTLCStats {
-                       pending_htlcs: self.context.pending_outbound_htlcs.len() as u32,
-                       pending_htlcs_value_msat: 0,
-                       on_counterparty_tx_dust_exposure_msat: 0,
-                       on_holder_tx_dust_exposure_msat: 0,
-                       holding_cell_msat: 0,
-                       on_holder_tx_holding_cell_htlcs_count: 0,
-               };
+               self.context.counterparty_cur_commitment_point = Some(msg.first_per_commitment_point);
+               self.context.counterparty_shutdown_scriptpubkey = counterparty_shutdown_scriptpubkey;
 
-               let (htlc_timeout_dust_limit, htlc_success_dust_limit) = if self.context.opt_anchors() {
-                       (0, 0)
-               } else {
-                       let dust_buffer_feerate = self.get_dust_buffer_feerate(outbound_feerate_update) as u64;
-                       (dust_buffer_feerate * htlc_timeout_tx_weight(false) / 1000,
-                               dust_buffer_feerate * htlc_success_tx_weight(false) / 1000)
-               };
-               let counterparty_dust_limit_success_sat = htlc_success_dust_limit + self.context.counterparty_dust_limit_satoshis;
-               let holder_dust_limit_timeout_sat = htlc_timeout_dust_limit + self.context.holder_dust_limit_satoshis;
-               for ref htlc in self.context.pending_outbound_htlcs.iter() {
-                       stats.pending_htlcs_value_msat += htlc.amount_msat;
-                       if htlc.amount_msat / 1000 < counterparty_dust_limit_success_sat {
-                               stats.on_counterparty_tx_dust_exposure_msat += htlc.amount_msat;
-                       }
-                       if htlc.amount_msat / 1000 < holder_dust_limit_timeout_sat {
-                               stats.on_holder_tx_dust_exposure_msat += htlc.amount_msat;
-                       }
-               }
+               self.context.channel_state = ChannelState::OurInitSent as u32 | ChannelState::TheirInitSent as u32;
+               self.context.inbound_handshake_limits_override = None; // We're done enforcing limits on our peer's handshake now.
 
-               for update in self.context.holding_cell_htlc_updates.iter() {
-                       if let &HTLCUpdateAwaitingACK::AddHTLC { ref amount_msat, .. } = update {
-                               stats.pending_htlcs += 1;
-                               stats.pending_htlcs_value_msat += amount_msat;
-                               stats.holding_cell_msat += amount_msat;
-                               if *amount_msat / 1000 < counterparty_dust_limit_success_sat {
-                                       stats.on_counterparty_tx_dust_exposure_msat += amount_msat;
-                               }
-                               if *amount_msat / 1000 < holder_dust_limit_timeout_sat {
-                                       stats.on_holder_tx_dust_exposure_msat += amount_msat;
-                               } else {
-                                       stats.on_holder_tx_holding_cell_htlcs_count += 1;
-                               }
-                       }
-               }
-               stats
+               Ok(())
        }
 
-       /// Get the available balances, see [`AvailableBalances`]'s fields for more info.
-       /// Doesn't bother handling the
-       /// if-we-removed-it-already-but-haven't-fully-resolved-they-can-still-send-an-inbound-HTLC
-       /// corner case properly.
-       pub fn get_available_balances(&self) -> AvailableBalances {
-               // Note that we have to handle overflow due to the above case.
-               let inbound_stats = self.get_inbound_pending_htlc_stats(None);
-               let outbound_stats = self.get_outbound_pending_htlc_stats(None);
+       fn funding_created_signature<L: Deref>(&mut self, sig: &Signature, logger: &L) -> Result<(Txid, CommitmentTransaction, Signature), ChannelError> where L::Target: Logger {
+               let funding_script = self.context.get_funding_redeemscript();
 
-               let mut balance_msat = self.context.value_to_self_msat;
-               for ref htlc in self.context.pending_inbound_htlcs.iter() {
-                       if let InboundHTLCState::LocalRemoved(InboundHTLCRemovalReason::Fulfill(_)) = htlc.state {
-                               balance_msat += htlc.amount_msat;
-                       }
+               let keys = self.context.build_holder_transaction_keys(self.context.cur_holder_commitment_transaction_number);
+               let initial_commitment_tx = self.context.build_commitment_transaction(self.context.cur_holder_commitment_transaction_number, &keys, true, false, logger).tx;
+               {
+                       let trusted_tx = initial_commitment_tx.trust();
+                       let initial_commitment_bitcoin_tx = trusted_tx.built_transaction();
+                       let sighash = initial_commitment_bitcoin_tx.get_sighash_all(&funding_script, self.context.channel_value_satoshis);
+                       // They sign the holder commitment transaction...
+                       log_trace!(logger, "Checking funding_created tx signature {} by key {} against tx {} (sighash {}) with redeemscript {} for channel {}.",
+                               log_bytes!(sig.serialize_compact()[..]), log_bytes!(self.context.counterparty_funding_pubkey().serialize()),
+                               encode::serialize_hex(&initial_commitment_bitcoin_tx.transaction), log_bytes!(sighash[..]),
+                               encode::serialize_hex(&funding_script), log_bytes!(self.context.channel_id()));
+                       secp_check!(self.context.secp_ctx.verify_ecdsa(&sighash, &sig, self.context.counterparty_funding_pubkey()), "Invalid funding_created signature from peer".to_owned());
                }
-               balance_msat -= outbound_stats.pending_htlcs_value_msat;
-
-               let outbound_capacity_msat = self.context.value_to_self_msat
-                               .saturating_sub(outbound_stats.pending_htlcs_value_msat)
-                               .saturating_sub(
-                                       self.context.counterparty_selected_channel_reserve_satoshis.unwrap_or(0) * 1000);
 
-               let mut available_capacity_msat = outbound_capacity_msat;
+               let counterparty_keys = self.context.build_remote_transaction_keys();
+               let counterparty_initial_commitment_tx = self.context.build_commitment_transaction(self.context.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, false, logger).tx;
 
-               if self.context.is_outbound() {
-                       // We should mind channel commit tx fee when computing how much of the available capacity
-                       // can be used in the next htlc. Mirrors the logic in send_htlc.
-                       //
-                       // The fee depends on whether the amount we will be sending is above dust or not,
-                       // and the answer will in turn change the amount itself â€” making it a circular
-                       // dependency.
-                       // This complicates the computation around dust-values, up to the one-htlc-value.
-                       let mut real_dust_limit_timeout_sat = self.context.holder_dust_limit_satoshis;
-                       if !self.context.opt_anchors() {
-                               real_dust_limit_timeout_sat += self.context.feerate_per_kw as u64 * htlc_timeout_tx_weight(false) / 1000;
-                       }
+               let counterparty_trusted_tx = counterparty_initial_commitment_tx.trust();
+               let counterparty_initial_bitcoin_tx = counterparty_trusted_tx.built_transaction();
+               log_trace!(logger, "Initial counterparty tx for channel {} is: txid {} tx {}",
+                       log_bytes!(self.context.channel_id()), counterparty_initial_bitcoin_tx.txid, encode::serialize_hex(&counterparty_initial_bitcoin_tx.transaction));
 
-                       let htlc_above_dust = HTLCCandidate::new(real_dust_limit_timeout_sat * 1000, HTLCInitiator::LocalOffered);
-                       let max_reserved_commit_tx_fee_msat = FEE_SPIKE_BUFFER_FEE_INCREASE_MULTIPLE * self.next_local_commit_tx_fee_msat(htlc_above_dust, Some(()));
-                       let htlc_dust = HTLCCandidate::new(real_dust_limit_timeout_sat * 1000 - 1, HTLCInitiator::LocalOffered);
-                       let min_reserved_commit_tx_fee_msat = FEE_SPIKE_BUFFER_FEE_INCREASE_MULTIPLE * self.next_local_commit_tx_fee_msat(htlc_dust, Some(()));
+               let counterparty_signature = self.context.holder_signer.sign_counterparty_commitment(&counterparty_initial_commitment_tx, Vec::new(), &self.context.secp_ctx)
+                               .map_err(|_| ChannelError::Close("Failed to get signatures for new commitment_signed".to_owned()))?.0;
 
-                       // We will first subtract the fee as if we were above-dust. Then, if the resulting
-                       // value ends up being below dust, we have this fee available again. In that case,
-                       // match the value to right-below-dust.
-                       let mut capacity_minus_commitment_fee_msat: i64 = (available_capacity_msat as i64) - (max_reserved_commit_tx_fee_msat as i64);
-                       if capacity_minus_commitment_fee_msat < (real_dust_limit_timeout_sat as i64) * 1000 {
-                               let one_htlc_difference_msat = max_reserved_commit_tx_fee_msat - min_reserved_commit_tx_fee_msat;
-                               debug_assert!(one_htlc_difference_msat != 0);
-                               capacity_minus_commitment_fee_msat += one_htlc_difference_msat as i64;
-                               capacity_minus_commitment_fee_msat = cmp::min(real_dust_limit_timeout_sat as i64 * 1000 - 1, capacity_minus_commitment_fee_msat);
-                               available_capacity_msat = cmp::max(0, cmp::min(capacity_minus_commitment_fee_msat, available_capacity_msat as i64)) as u64;
-                       } else {
-                               available_capacity_msat = capacity_minus_commitment_fee_msat as u64;
-                       }
-               } else {
-                       // If the channel is inbound (i.e. counterparty pays the fee), we need to make sure
-                       // sending a new HTLC won't reduce their balance below our reserve threshold.
-                       let mut real_dust_limit_success_sat = self.context.counterparty_dust_limit_satoshis;
-                       if !self.context.opt_anchors() {
-                               real_dust_limit_success_sat += self.context.feerate_per_kw as u64 * htlc_success_tx_weight(false) / 1000;
-                       }
+               // We sign "counterparty" commitment transaction, allowing them to broadcast the tx if they wish.
+               Ok((counterparty_initial_bitcoin_tx.txid, initial_commitment_tx, counterparty_signature))
+       }
 
-                       let htlc_above_dust = HTLCCandidate::new(real_dust_limit_success_sat * 1000, HTLCInitiator::LocalOffered);
-                       let max_reserved_commit_tx_fee_msat = self.next_remote_commit_tx_fee_msat(htlc_above_dust, None);
+       pub fn funding_created<SP: Deref, L: Deref>(
+               &mut self, msg: &msgs::FundingCreated, best_block: BestBlock, signer_provider: &SP, logger: &L
+       ) -> Result<(msgs::FundingSigned, ChannelMonitor<Signer>), ChannelError>
+       where
+               SP::Target: SignerProvider<Signer = Signer>,
+               L::Target: Logger
+       {
+               if self.context.is_outbound() {
+                       return Err(ChannelError::Close("Received funding_created for an outbound channel?".to_owned()));
+               }
+               if self.context.channel_state != (ChannelState::OurInitSent as u32 | ChannelState::TheirInitSent as u32) {
+                       // BOLT 2 says that if we disconnect before we send funding_signed we SHOULD NOT
+                       // remember the channel, so it's safe to just send an error_message here and drop the
+                       // channel.
+                       return Err(ChannelError::Close("Received funding_created after we got the channel!".to_owned()));
+               }
+               if self.context.inbound_awaiting_accept {
+                       return Err(ChannelError::Close("FundingCreated message received before the channel was accepted".to_owned()));
+               }
+               if self.context.commitment_secrets.get_min_seen_secret() != (1 << 48) ||
+                               self.context.cur_counterparty_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER ||
+                               self.context.cur_holder_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER {
+                       panic!("Should not have advanced channel commitment tx numbers prior to funding_created");
+               }
 
-                       let holder_selected_chan_reserve_msat = self.context.holder_selected_channel_reserve_satoshis * 1000;
-                       let remote_balance_msat = (self.context.channel_value_satoshis * 1000 - self.context.value_to_self_msat)
-                               .saturating_sub(inbound_stats.pending_htlcs_value_msat);
+               let funding_txo = OutPoint { txid: msg.funding_txid, index: msg.funding_output_index };
+               self.context.channel_transaction_parameters.funding_outpoint = Some(funding_txo);
+               // This is an externally observable change before we finish all our checks.  In particular
+               // funding_created_signature may fail.
+               self.context.holder_signer.provide_channel_parameters(&self.context.channel_transaction_parameters);
 
-                       if remote_balance_msat < max_reserved_commit_tx_fee_msat + holder_selected_chan_reserve_msat {
-                               // If another HTLC's fee would reduce the remote's balance below the reserve limit
-                               // we've selected for them, we can only send dust HTLCs.
-                               available_capacity_msat = cmp::min(available_capacity_msat, real_dust_limit_success_sat * 1000 - 1);
+               let (counterparty_initial_commitment_txid, initial_commitment_tx, signature) = match self.funding_created_signature(&msg.signature, logger) {
+                       Ok(res) => res,
+                       Err(ChannelError::Close(e)) => {
+                               self.context.channel_transaction_parameters.funding_outpoint = None;
+                               return Err(ChannelError::Close(e));
+                       },
+                       Err(e) => {
+                               // The only error we know how to handle is ChannelError::Close, so we fall over here
+                               // to make sure we don't continue with an inconsistent state.
+                               panic!("unexpected error type from funding_created_signature {:?}", e);
                        }
-               }
-
-               let mut next_outbound_htlc_minimum_msat = self.context.counterparty_htlc_minimum_msat;
+               };
 
-               // If we get close to our maximum dust exposure, we end up in a situation where we can send
-               // between zero and the remaining dust exposure limit remaining OR above the dust limit.
-               // Because we cannot express this as a simple min/max, we prefer to tell the user they can
-               // send above the dust limit (as the router can always overpay to meet the dust limit).
-               let mut remaining_msat_below_dust_exposure_limit = None;
-               let mut dust_exposure_dust_limit_msat = 0;
+               let holder_commitment_tx = HolderCommitmentTransaction::new(
+                       initial_commitment_tx,
+                       msg.signature,
+                       Vec::new(),
+                       &self.context.get_holder_pubkeys().funding_pubkey,
+                       self.context.counterparty_funding_pubkey()
+               );
 
-               let (htlc_success_dust_limit, htlc_timeout_dust_limit) = if self.context.opt_anchors() {
-                       (self.context.counterparty_dust_limit_satoshis, self.context.holder_dust_limit_satoshis)
-               } else {
-                       let dust_buffer_feerate = self.get_dust_buffer_feerate(None) as u64;
-                       (self.context.counterparty_dust_limit_satoshis + dust_buffer_feerate * htlc_success_tx_weight(false) / 1000,
-                        self.context.holder_dust_limit_satoshis       + dust_buffer_feerate * htlc_timeout_tx_weight(false) / 1000)
-               };
-               let on_counterparty_dust_htlc_exposure_msat = inbound_stats.on_counterparty_tx_dust_exposure_msat + outbound_stats.on_counterparty_tx_dust_exposure_msat;
-               if on_counterparty_dust_htlc_exposure_msat as i64 + htlc_success_dust_limit as i64 * 1000 - 1 > self.get_max_dust_htlc_exposure_msat() as i64 {
-                       remaining_msat_below_dust_exposure_limit =
-                               Some(self.get_max_dust_htlc_exposure_msat().saturating_sub(on_counterparty_dust_htlc_exposure_msat));
-                       dust_exposure_dust_limit_msat = cmp::max(dust_exposure_dust_limit_msat, htlc_success_dust_limit * 1000);
-               }
+               self.context.holder_signer.validate_holder_commitment(&holder_commitment_tx, Vec::new())
+                       .map_err(|_| ChannelError::Close("Failed to validate our commitment".to_owned()))?;
 
-               let on_holder_dust_htlc_exposure_msat = inbound_stats.on_holder_tx_dust_exposure_msat + outbound_stats.on_holder_tx_dust_exposure_msat;
-               if on_holder_dust_htlc_exposure_msat as i64 + htlc_timeout_dust_limit as i64 * 1000 - 1 > self.get_max_dust_htlc_exposure_msat() as i64 {
-                       remaining_msat_below_dust_exposure_limit = Some(cmp::min(
-                               remaining_msat_below_dust_exposure_limit.unwrap_or(u64::max_value()),
-                               self.get_max_dust_htlc_exposure_msat().saturating_sub(on_holder_dust_htlc_exposure_msat)));
-                       dust_exposure_dust_limit_msat = cmp::max(dust_exposure_dust_limit_msat, htlc_timeout_dust_limit * 1000);
-               }
+                       // Now that we're past error-generating stuff, update our local state:
 
-               if let Some(remaining_limit_msat) = remaining_msat_below_dust_exposure_limit {
-                       if available_capacity_msat < dust_exposure_dust_limit_msat {
-                               available_capacity_msat = cmp::min(available_capacity_msat, remaining_limit_msat);
-                       } else {
-                               next_outbound_htlc_minimum_msat = cmp::max(next_outbound_htlc_minimum_msat, dust_exposure_dust_limit_msat);
-                       }
-               }
+               let funding_redeemscript = self.context.get_funding_redeemscript();
+               let funding_txo_script = funding_redeemscript.to_v0_p2wsh();
+               let obscure_factor = get_commitment_transaction_number_obscure_factor(&self.context.get_holder_pubkeys().payment_point, &self.context.get_counterparty_pubkeys().payment_point, self.context.is_outbound());
+               let shutdown_script = self.context.shutdown_scriptpubkey.clone().map(|script| script.into_inner());
+               let mut monitor_signer = signer_provider.derive_channel_signer(self.context.channel_value_satoshis, self.context.channel_keys_id);
+               monitor_signer.provide_channel_parameters(&self.context.channel_transaction_parameters);
+               let channel_monitor = ChannelMonitor::new(self.context.secp_ctx.clone(), monitor_signer,
+                                                         shutdown_script, self.context.get_holder_selected_contest_delay(),
+                                                         &self.context.destination_script, (funding_txo, funding_txo_script.clone()),
+                                                         &self.context.channel_transaction_parameters,
+                                                         funding_redeemscript.clone(), self.context.channel_value_satoshis,
+                                                         obscure_factor,
+                                                         holder_commitment_tx, best_block, self.context.counterparty_node_id);
 
-               available_capacity_msat = cmp::min(available_capacity_msat,
-                       self.context.counterparty_max_htlc_value_in_flight_msat - outbound_stats.pending_htlcs_value_msat);
+               channel_monitor.provide_latest_counterparty_commitment_tx(counterparty_initial_commitment_txid, Vec::new(), self.context.cur_counterparty_commitment_transaction_number, self.context.counterparty_cur_commitment_point.unwrap(), logger);
 
-               if outbound_stats.pending_htlcs + 1 > self.context.counterparty_max_accepted_htlcs as u32 {
-                       available_capacity_msat = 0;
-               }
+               self.context.channel_state = ChannelState::FundingSent as u32;
+               self.context.channel_id = funding_txo.to_channel_id();
+               self.context.cur_counterparty_commitment_transaction_number -= 1;
+               self.context.cur_holder_commitment_transaction_number -= 1;
 
-               AvailableBalances {
-                       inbound_capacity_msat: cmp::max(self.context.channel_value_satoshis as i64 * 1000
-                                       - self.context.value_to_self_msat as i64
-                                       - self.get_inbound_pending_htlc_stats(None).pending_htlcs_value_msat as i64
-                                       - self.context.holder_selected_channel_reserve_satoshis as i64 * 1000,
-                               0) as u64,
-                       outbound_capacity_msat,
-                       next_outbound_htlc_limit_msat: available_capacity_msat,
-                       next_outbound_htlc_minimum_msat,
-                       balance_msat,
-               }
-       }
+               log_info!(logger, "Generated funding_signed for peer for channel {}", log_bytes!(self.context.channel_id()));
 
-       pub fn get_holder_counterparty_selected_channel_reserve_satoshis(&self) -> (u64, Option<u64>) {
-               (self.context.holder_selected_channel_reserve_satoshis, self.context.counterparty_selected_channel_reserve_satoshis)
-       }
+               let need_channel_ready = self.check_get_channel_ready(0).is_some();
+               self.monitor_updating_paused(false, false, need_channel_ready, Vec::new(), Vec::new(), Vec::new());
 
-       // Get the fee cost in MSATS of a commitment tx with a given number of HTLC outputs.
-       // Note that num_htlcs should not include dust HTLCs.
-       fn commit_tx_fee_msat(feerate_per_kw: u32, num_htlcs: usize, opt_anchors: bool) -> u64 {
-               // Note that we need to divide before multiplying to round properly,
-               // since the lowest denomination of bitcoin on-chain is the satoshi.
-               (commitment_tx_base_weight(opt_anchors) + num_htlcs as u64 * COMMITMENT_TX_WEIGHT_PER_HTLC) * feerate_per_kw as u64 / 1000 * 1000
+               Ok((msgs::FundingSigned {
+                       channel_id: self.context.channel_id,
+                       signature,
+                       #[cfg(taproot)]
+                       partial_signature_with_nonce: None,
+               }, channel_monitor))
        }
 
-       // Get the fee cost in SATS of a commitment tx with a given number of HTLC outputs.
-       // Note that num_htlcs should not include dust HTLCs.
-       #[inline]
-       fn commit_tx_fee_sat(feerate_per_kw: u32, num_htlcs: usize, opt_anchors: bool) -> u64 {
-               feerate_per_kw as u64 * (commitment_tx_base_weight(opt_anchors) + num_htlcs as u64 * COMMITMENT_TX_WEIGHT_PER_HTLC) / 1000
-       }
+       /// Handles a funding_signed message from the remote end.
+       /// If this call is successful, broadcast the funding transaction (and not before!)
+       pub fn funding_signed<SP: Deref, L: Deref>(
+               &mut self, msg: &msgs::FundingSigned, best_block: BestBlock, signer_provider: &SP, logger: &L
+       ) -> Result<ChannelMonitor<Signer>, ChannelError>
+       where
+               SP::Target: SignerProvider<Signer = Signer>,
+               L::Target: Logger
+       {
+               if !self.context.is_outbound() {
+                       return Err(ChannelError::Close("Received funding_signed for an inbound channel?".to_owned()));
+               }
+               if self.context.channel_state & !(ChannelState::MonitorUpdateInProgress as u32) != ChannelState::FundingCreated as u32 {
+                       return Err(ChannelError::Close("Received funding_signed in strange state!".to_owned()));
+               }
+               if self.context.commitment_secrets.get_min_seen_secret() != (1 << 48) ||
+                               self.context.cur_counterparty_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER ||
+                               self.context.cur_holder_commitment_transaction_number != INITIAL_COMMITMENT_NUMBER {
+                       panic!("Should not have advanced channel commitment tx numbers prior to funding_created");
+               }
 
-       /// Get the commitment tx fee for the local's (i.e. our) next commitment transaction based on the
-       /// number of pending HTLCs that are on track to be in our next commitment tx.
-       ///
-       /// Optionally includes the `HTLCCandidate` given by `htlc` and an additional non-dust HTLC if
-       /// `fee_spike_buffer_htlc` is `Some`.
-       ///
-       /// The first extra HTLC is useful for determining whether we can accept a further HTLC, the
-       /// second allows for creating a buffer to ensure a further HTLC can always be accepted/added.
-       ///
-       /// Dust HTLCs are excluded.
-       fn next_local_commit_tx_fee_msat(&self, htlc: HTLCCandidate, fee_spike_buffer_htlc: Option<()>) -> u64 {
-               assert!(self.context.is_outbound());
+               let funding_script = self.context.get_funding_redeemscript();
 
-               let (htlc_success_dust_limit, htlc_timeout_dust_limit) = if self.context.opt_anchors() {
-                       (0, 0)
-               } else {
-                       (self.context.feerate_per_kw as u64 * htlc_success_tx_weight(false) / 1000,
-                               self.context.feerate_per_kw as u64 * htlc_timeout_tx_weight(false) / 1000)
-               };
-               let real_dust_limit_success_sat = htlc_success_dust_limit + self.context.holder_dust_limit_satoshis;
-               let real_dust_limit_timeout_sat = htlc_timeout_dust_limit + self.context.holder_dust_limit_satoshis;
+               let counterparty_keys = self.context.build_remote_transaction_keys();
+               let counterparty_initial_commitment_tx = self.context.build_commitment_transaction(self.context.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, false, logger).tx;
+               let counterparty_trusted_tx = counterparty_initial_commitment_tx.trust();
+               let counterparty_initial_bitcoin_tx = counterparty_trusted_tx.built_transaction();
 
-               let mut addl_htlcs = 0;
-               if fee_spike_buffer_htlc.is_some() { addl_htlcs += 1; }
-               match htlc.origin {
-                       HTLCInitiator::LocalOffered => {
-                               if htlc.amount_msat / 1000 >= real_dust_limit_timeout_sat {
-                                       addl_htlcs += 1;
-                               }
-                       },
-                       HTLCInitiator::RemoteOffered => {
-                               if htlc.amount_msat / 1000 >= real_dust_limit_success_sat {
-                                       addl_htlcs += 1;
-                               }
-                       }
-               }
+               log_trace!(logger, "Initial counterparty tx for channel {} is: txid {} tx {}",
+                       log_bytes!(self.context.channel_id()), counterparty_initial_bitcoin_tx.txid, encode::serialize_hex(&counterparty_initial_bitcoin_tx.transaction));
 
-               let mut included_htlcs = 0;
-               for ref htlc in self.context.pending_inbound_htlcs.iter() {
-                       if htlc.amount_msat / 1000 < real_dust_limit_success_sat {
-                               continue
+               let holder_signer = self.context.build_holder_transaction_keys(self.context.cur_holder_commitment_transaction_number);
+               let initial_commitment_tx = self.context.build_commitment_transaction(self.context.cur_holder_commitment_transaction_number, &holder_signer, true, false, logger).tx;
+               {
+                       let trusted_tx = initial_commitment_tx.trust();
+                       let initial_commitment_bitcoin_tx = trusted_tx.built_transaction();
+                       let sighash = initial_commitment_bitcoin_tx.get_sighash_all(&funding_script, self.context.channel_value_satoshis);
+                       // They sign our commitment transaction, allowing us to broadcast the tx if we wish.
+                       if let Err(_) = self.context.secp_ctx.verify_ecdsa(&sighash, &msg.signature, &self.context.get_counterparty_pubkeys().funding_pubkey) {
+                               return Err(ChannelError::Close("Invalid funding_signed signature from peer".to_owned()));
                        }
-                       // We include LocalRemoved HTLCs here because we may still need to broadcast a commitment
-                       // transaction including this HTLC if it times out before they RAA.
-                       included_htlcs += 1;
                }
 
-               for ref htlc in self.context.pending_outbound_htlcs.iter() {
-                       if htlc.amount_msat / 1000 < real_dust_limit_timeout_sat {
-                               continue
-                       }
-                       match htlc.state {
-                               OutboundHTLCState::LocalAnnounced {..} => included_htlcs += 1,
-                               OutboundHTLCState::Committed => included_htlcs += 1,
-                               OutboundHTLCState::RemoteRemoved {..} => included_htlcs += 1,
-                               // We don't include AwaitingRemoteRevokeToRemove HTLCs because our next commitment
-                               // transaction won't be generated until they send us their next RAA, which will mean
-                               // dropping any HTLCs in this state.
-                               _ => {},
-                       }
-               }
+               let holder_commitment_tx = HolderCommitmentTransaction::new(
+                       initial_commitment_tx,
+                       msg.signature,
+                       Vec::new(),
+                       &self.context.get_holder_pubkeys().funding_pubkey,
+                       self.context.counterparty_funding_pubkey()
+               );
 
-               for htlc in self.context.holding_cell_htlc_updates.iter() {
-                       match htlc {
-                               &HTLCUpdateAwaitingACK::AddHTLC { amount_msat, .. } => {
-                                       if amount_msat / 1000 < real_dust_limit_timeout_sat {
-                                               continue
-                                       }
-                                       included_htlcs += 1
-                               },
-                               _ => {}, // Don't include claims/fails that are awaiting ack, because once we get the
-                                        // ack we're guaranteed to never include them in commitment txs anymore.
-                       }
-               }
+               self.context.holder_signer.validate_holder_commitment(&holder_commitment_tx, Vec::new())
+                       .map_err(|_| ChannelError::Close("Failed to validate our commitment".to_owned()))?;
 
-               let num_htlcs = included_htlcs + addl_htlcs;
-               let res = Self::commit_tx_fee_msat(self.context.feerate_per_kw, num_htlcs, self.context.opt_anchors());
-               #[cfg(any(test, fuzzing))]
-               {
-                       let mut fee = res;
-                       if fee_spike_buffer_htlc.is_some() {
-                               fee = Self::commit_tx_fee_msat(self.context.feerate_per_kw, num_htlcs - 1, self.context.opt_anchors());
-                       }
-                       let total_pending_htlcs = self.context.pending_inbound_htlcs.len() + self.context.pending_outbound_htlcs.len()
-                               + self.context.holding_cell_htlc_updates.len();
-                       let commitment_tx_info = CommitmentTxInfoCached {
-                               fee,
-                               total_pending_htlcs,
-                               next_holder_htlc_id: match htlc.origin {
-                                       HTLCInitiator::LocalOffered => self.context.next_holder_htlc_id + 1,
-                                       HTLCInitiator::RemoteOffered => self.context.next_holder_htlc_id,
-                               },
-                               next_counterparty_htlc_id: match htlc.origin {
-                                       HTLCInitiator::LocalOffered => self.context.next_counterparty_htlc_id,
-                                       HTLCInitiator::RemoteOffered => self.context.next_counterparty_htlc_id + 1,
-                               },
-                               feerate: self.context.feerate_per_kw,
-                       };
-                       *self.context.next_local_commitment_tx_fee_info_cached.lock().unwrap() = Some(commitment_tx_info);
-               }
-               res
-       }
 
-       /// Get the commitment tx fee for the remote's next commitment transaction based on the number of
-       /// pending HTLCs that are on track to be in their next commitment tx
-       ///
-       /// Optionally includes the `HTLCCandidate` given by `htlc` and an additional non-dust HTLC if
-       /// `fee_spike_buffer_htlc` is `Some`.
-       ///
-       /// The first extra HTLC is useful for determining whether we can accept a further HTLC, the
-       /// second allows for creating a buffer to ensure a further HTLC can always be accepted/added.
-       ///
-       /// Dust HTLCs are excluded.
-       fn next_remote_commit_tx_fee_msat(&self, htlc: HTLCCandidate, fee_spike_buffer_htlc: Option<()>) -> u64 {
-               assert!(!self.context.is_outbound());
+               let funding_redeemscript = self.context.get_funding_redeemscript();
+               let funding_txo = self.context.get_funding_txo().unwrap();
+               let funding_txo_script = funding_redeemscript.to_v0_p2wsh();
+               let obscure_factor = get_commitment_transaction_number_obscure_factor(&self.context.get_holder_pubkeys().payment_point, &self.context.get_counterparty_pubkeys().payment_point, self.context.is_outbound());
+               let shutdown_script = self.context.shutdown_scriptpubkey.clone().map(|script| script.into_inner());
+               let mut monitor_signer = signer_provider.derive_channel_signer(self.context.channel_value_satoshis, self.context.channel_keys_id);
+               monitor_signer.provide_channel_parameters(&self.context.channel_transaction_parameters);
+               let channel_monitor = ChannelMonitor::new(self.context.secp_ctx.clone(), monitor_signer,
+                                                         shutdown_script, self.context.get_holder_selected_contest_delay(),
+                                                         &self.context.destination_script, (funding_txo, funding_txo_script),
+                                                         &self.context.channel_transaction_parameters,
+                                                         funding_redeemscript.clone(), self.context.channel_value_satoshis,
+                                                         obscure_factor,
+                                                         holder_commitment_tx, best_block, self.context.counterparty_node_id);
 
-               let (htlc_success_dust_limit, htlc_timeout_dust_limit) = if self.context.opt_anchors() {
-                       (0, 0)
-               } else {
-                       (self.context.feerate_per_kw as u64 * htlc_success_tx_weight(false) / 1000,
-                               self.context.feerate_per_kw as u64 * htlc_timeout_tx_weight(false) / 1000)
-               };
-               let real_dust_limit_success_sat = htlc_success_dust_limit + self.context.counterparty_dust_limit_satoshis;
-               let real_dust_limit_timeout_sat = htlc_timeout_dust_limit + self.context.counterparty_dust_limit_satoshis;
+               channel_monitor.provide_latest_counterparty_commitment_tx(counterparty_initial_bitcoin_tx.txid, Vec::new(), self.context.cur_counterparty_commitment_transaction_number, self.context.counterparty_cur_commitment_point.unwrap(), logger);
 
-               let mut addl_htlcs = 0;
-               if fee_spike_buffer_htlc.is_some() { addl_htlcs += 1; }
-               match htlc.origin {
-                       HTLCInitiator::LocalOffered => {
-                               if htlc.amount_msat / 1000 >= real_dust_limit_success_sat {
-                                       addl_htlcs += 1;
-                               }
-                       },
-                       HTLCInitiator::RemoteOffered => {
-                               if htlc.amount_msat / 1000 >= real_dust_limit_timeout_sat {
-                                       addl_htlcs += 1;
-                               }
-                       }
-               }
+               assert_eq!(self.context.channel_state & (ChannelState::MonitorUpdateInProgress as u32), 0); // We have no had any monitor(s) yet to fail update!
+               self.context.channel_state = ChannelState::FundingSent as u32;
+               self.context.cur_holder_commitment_transaction_number -= 1;
+               self.context.cur_counterparty_commitment_transaction_number -= 1;
 
-               // When calculating the set of HTLCs which will be included in their next commitment_signed, all
-               // non-dust inbound HTLCs are included (as all states imply it will be included) and only
-               // committed outbound HTLCs, see below.
-               let mut included_htlcs = 0;
-               for ref htlc in self.context.pending_inbound_htlcs.iter() {
-                       if htlc.amount_msat / 1000 <= real_dust_limit_timeout_sat {
-                               continue
-                       }
-                       included_htlcs += 1;
+               log_info!(logger, "Received funding_signed from peer for channel {}", log_bytes!(self.context.channel_id()));
+
+               let need_channel_ready = self.check_get_channel_ready(0).is_some();
+               self.monitor_updating_paused(false, false, need_channel_ready, Vec::new(), Vec::new(), Vec::new());
+               Ok(channel_monitor)
+       }
+
+       /// Handles a channel_ready message from our peer. If we've already sent our channel_ready
+       /// and the channel is now usable (and public), this may generate an announcement_signatures to
+       /// reply with.
+       pub fn channel_ready<NS: Deref, L: Deref>(
+               &mut self, msg: &msgs::ChannelReady, node_signer: &NS, genesis_block_hash: BlockHash,
+               user_config: &UserConfig, best_block: &BestBlock, logger: &L
+       ) -> Result<Option<msgs::AnnouncementSignatures>, ChannelError>
+       where
+               NS::Target: NodeSigner,
+               L::Target: Logger
+       {
+               if self.context.channel_state & (ChannelState::PeerDisconnected as u32) == ChannelState::PeerDisconnected as u32 {
+                       self.context.workaround_lnd_bug_4006 = Some(msg.clone());
+                       return Err(ChannelError::Ignore("Peer sent channel_ready when we needed a channel_reestablish. The peer is likely lnd, see https://github.com/lightningnetwork/lnd/issues/4006".to_owned()));
                }
 
-               for ref htlc in self.context.pending_outbound_htlcs.iter() {
-                       if htlc.amount_msat / 1000 <= real_dust_limit_success_sat {
-                               continue
-                       }
-                       // We only include outbound HTLCs if it will not be included in their next commitment_signed,
-                       // i.e. if they've responded to us with an RAA after announcement.
-                       match htlc.state {
-                               OutboundHTLCState::Committed => included_htlcs += 1,
-                               OutboundHTLCState::RemoteRemoved {..} => included_htlcs += 1,
-                               OutboundHTLCState::LocalAnnounced { .. } => included_htlcs += 1,
-                               _ => {},
+               if let Some(scid_alias) = msg.short_channel_id_alias {
+                       if Some(scid_alias) != self.context.short_channel_id {
+                               // The scid alias provided can be used to route payments *from* our counterparty,
+                               // i.e. can be used for inbound payments and provided in invoices, but is not used
+                               // when routing outbound payments.
+                               self.context.latest_inbound_scid_alias = Some(scid_alias);
                        }
                }
 
-               let num_htlcs = included_htlcs + addl_htlcs;
-               let res = Self::commit_tx_fee_msat(self.context.feerate_per_kw, num_htlcs, self.context.opt_anchors());
-               #[cfg(any(test, fuzzing))]
+               let non_shutdown_state = self.context.channel_state & (!MULTI_STATE_FLAGS);
+
+               if non_shutdown_state == ChannelState::FundingSent as u32 {
+                       self.context.channel_state |= ChannelState::TheirChannelReady as u32;
+               } else if non_shutdown_state == (ChannelState::FundingSent as u32 | ChannelState::OurChannelReady as u32) {
+                       self.context.channel_state = ChannelState::ChannelReady as u32 | (self.context.channel_state & MULTI_STATE_FLAGS);
+                       self.context.update_time_counter += 1;
+               } else if self.context.channel_state & (ChannelState::ChannelReady as u32) != 0 ||
+                       // If we reconnected before sending our `channel_ready` they may still resend theirs:
+                       (self.context.channel_state & (ChannelState::FundingSent as u32 | ChannelState::TheirChannelReady as u32) ==
+                                             (ChannelState::FundingSent as u32 | ChannelState::TheirChannelReady as u32))
                {
-                       let mut fee = res;
-                       if fee_spike_buffer_htlc.is_some() {
-                               fee = Self::commit_tx_fee_msat(self.context.feerate_per_kw, num_htlcs - 1, self.context.opt_anchors());
+                       // They probably disconnected/reconnected and re-sent the channel_ready, which is
+                       // required, or they're sending a fresh SCID alias.
+                       let expected_point =
+                               if self.context.cur_counterparty_commitment_transaction_number == INITIAL_COMMITMENT_NUMBER - 1 {
+                                       // If they haven't ever sent an updated point, the point they send should match
+                                       // the current one.
+                                       self.context.counterparty_cur_commitment_point
+                               } else if self.context.cur_counterparty_commitment_transaction_number == INITIAL_COMMITMENT_NUMBER - 2 {
+                                       // If we've advanced the commitment number once, the second commitment point is
+                                       // at `counterparty_prev_commitment_point`, which is not yet revoked.
+                                       debug_assert!(self.context.counterparty_prev_commitment_point.is_some());
+                                       self.context.counterparty_prev_commitment_point
+                               } else {
+                                       // If they have sent updated points, channel_ready is always supposed to match
+                                       // their "first" point, which we re-derive here.
+                                       Some(PublicKey::from_secret_key(&self.context.secp_ctx, &SecretKey::from_slice(
+                                                       &self.context.commitment_secrets.get_secret(INITIAL_COMMITMENT_NUMBER - 1).expect("We should have all prev secrets available")
+                                               ).expect("We already advanced, so previous secret keys should have been validated already")))
+                               };
+                       if expected_point != Some(msg.next_per_commitment_point) {
+                               return Err(ChannelError::Close("Peer sent a reconnect channel_ready with a different point".to_owned()));
                        }
-                       let total_pending_htlcs = self.context.pending_inbound_htlcs.len() + self.context.pending_outbound_htlcs.len();
-                       let commitment_tx_info = CommitmentTxInfoCached {
-                               fee,
-                               total_pending_htlcs,
-                               next_holder_htlc_id: match htlc.origin {
-                                       HTLCInitiator::LocalOffered => self.context.next_holder_htlc_id + 1,
-                                       HTLCInitiator::RemoteOffered => self.context.next_holder_htlc_id,
-                               },
-                               next_counterparty_htlc_id: match htlc.origin {
-                                       HTLCInitiator::LocalOffered => self.context.next_counterparty_htlc_id,
-                                       HTLCInitiator::RemoteOffered => self.context.next_counterparty_htlc_id + 1,
-                               },
-                               feerate: self.context.feerate_per_kw,
-                       };
-                       *self.context.next_remote_commitment_tx_fee_info_cached.lock().unwrap() = Some(commitment_tx_info);
+                       return Ok(None);
+               } else {
+                       return Err(ChannelError::Close("Peer sent a channel_ready at a strange time".to_owned()));
                }
-               res
+
+               self.context.counterparty_prev_commitment_point = self.context.counterparty_cur_commitment_point;
+               self.context.counterparty_cur_commitment_point = Some(msg.next_per_commitment_point);
+
+               log_info!(logger, "Received channel_ready from peer for channel {}", log_bytes!(self.context.channel_id()));
+
+               Ok(self.get_announcement_sigs(node_signer, genesis_block_hash, user_config, best_block.height(), logger))
        }
 
        pub fn update_add_htlc<F, L: Deref>(&mut self, msg: &msgs::UpdateAddHTLC, mut pending_forward_status: PendingHTLCStatus, create_pending_htlc_status: F, logger: &L) -> Result<(), ChannelError>
@@ -3127,8 +3384,8 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                        return Err(ChannelError::Close(format!("Remote side tried to send less than our minimum HTLC value. Lower limit: ({}). Actual: ({})", self.context.holder_htlc_minimum_msat, msg.amount_msat)));
                }
 
-               let inbound_stats = self.get_inbound_pending_htlc_stats(None);
-               let outbound_stats = self.get_outbound_pending_htlc_stats(None);
+               let inbound_stats = self.context.get_inbound_pending_htlc_stats(None);
+               let outbound_stats = self.context.get_outbound_pending_htlc_stats(None);
                if inbound_stats.pending_htlcs + 1 > self.context.holder_max_accepted_htlcs as u32 {
                        return Err(ChannelError::Close(format!("Remote tried to push more than our max accepted HTLCs ({})", self.context.holder_max_accepted_htlcs)));
                }
@@ -3159,16 +3416,16 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                let (htlc_timeout_dust_limit, htlc_success_dust_limit) = if self.context.opt_anchors() {
                        (0, 0)
                } else {
-                       let dust_buffer_feerate = self.get_dust_buffer_feerate(None) as u64;
+                       let dust_buffer_feerate = self.context.get_dust_buffer_feerate(None) as u64;
                        (dust_buffer_feerate * htlc_timeout_tx_weight(false) / 1000,
                                dust_buffer_feerate * htlc_success_tx_weight(false) / 1000)
                };
                let exposure_dust_limit_timeout_sats = htlc_timeout_dust_limit + self.context.counterparty_dust_limit_satoshis;
                if msg.amount_msat / 1000 < exposure_dust_limit_timeout_sats {
                        let on_counterparty_tx_dust_htlc_exposure_msat = inbound_stats.on_counterparty_tx_dust_exposure_msat + outbound_stats.on_counterparty_tx_dust_exposure_msat + msg.amount_msat;
-                       if on_counterparty_tx_dust_htlc_exposure_msat > self.get_max_dust_htlc_exposure_msat() {
+                       if on_counterparty_tx_dust_htlc_exposure_msat > self.context.get_max_dust_htlc_exposure_msat() {
                                log_info!(logger, "Cannot accept value that would put our exposure to dust HTLCs at {} over the limit {} on counterparty commitment tx",
-                                       on_counterparty_tx_dust_htlc_exposure_msat, self.get_max_dust_htlc_exposure_msat());
+                                       on_counterparty_tx_dust_htlc_exposure_msat, self.context.get_max_dust_htlc_exposure_msat());
                                pending_forward_status = create_pending_htlc_status(self, pending_forward_status, 0x1000|7);
                        }
                }
@@ -3176,9 +3433,9 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                let exposure_dust_limit_success_sats = htlc_success_dust_limit + self.context.holder_dust_limit_satoshis;
                if msg.amount_msat / 1000 < exposure_dust_limit_success_sats {
                        let on_holder_tx_dust_htlc_exposure_msat = inbound_stats.on_holder_tx_dust_exposure_msat + outbound_stats.on_holder_tx_dust_exposure_msat + msg.amount_msat;
-                       if on_holder_tx_dust_htlc_exposure_msat > self.get_max_dust_htlc_exposure_msat() {
+                       if on_holder_tx_dust_htlc_exposure_msat > self.context.get_max_dust_htlc_exposure_msat() {
                                log_info!(logger, "Cannot accept value that would put our exposure to dust HTLCs at {} over the limit {} on holder commitment tx",
-                                       on_holder_tx_dust_htlc_exposure_msat, self.get_max_dust_htlc_exposure_msat());
+                                       on_holder_tx_dust_htlc_exposure_msat, self.context.get_max_dust_htlc_exposure_msat());
                                pending_forward_status = create_pending_htlc_status(self, pending_forward_status, 0x1000|7);
                        }
                }
@@ -3195,7 +3452,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                // feerate_per_kw, while maintaining their channel reserve (as required by the spec).
                let remote_commit_tx_fee_msat = if self.context.is_outbound() { 0 } else {
                        let htlc_candidate = HTLCCandidate::new(msg.amount_msat, HTLCInitiator::RemoteOffered);
-                       self.next_remote_commit_tx_fee_msat(htlc_candidate, None) // Don't include the extra fee spike buffer HTLC in calculations
+                       self.context.next_remote_commit_tx_fee_msat(htlc_candidate, None) // Don't include the extra fee spike buffer HTLC in calculations
                };
                if pending_remote_value_msat - msg.amount_msat < remote_commit_tx_fee_msat {
                        return Err(ChannelError::Close("Remote HTLC add would not leave enough to pay for fees".to_owned()));
@@ -3215,17 +3472,17 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                        // still be able to afford adding this HTLC plus one more future HTLC, regardless of being
                        // sensitive to fee spikes.
                        let htlc_candidate = HTLCCandidate::new(msg.amount_msat, HTLCInitiator::RemoteOffered);
-                       let remote_fee_cost_incl_stuck_buffer_msat = 2 * self.next_remote_commit_tx_fee_msat(htlc_candidate, Some(()));
+                       let remote_fee_cost_incl_stuck_buffer_msat = 2 * self.context.next_remote_commit_tx_fee_msat(htlc_candidate, Some(()));
                        if pending_remote_value_msat - msg.amount_msat - self.context.holder_selected_channel_reserve_satoshis * 1000 < remote_fee_cost_incl_stuck_buffer_msat {
                                // Note that if the pending_forward_status is not updated here, then it's because we're already failing
                                // the HTLC, i.e. its status is already set to failing.
-                               log_info!(logger, "Attempting to fail HTLC due to fee spike buffer violation in channel {}. Rebalancing is required.", log_bytes!(self.channel_id()));
+                               log_info!(logger, "Attempting to fail HTLC due to fee spike buffer violation in channel {}. Rebalancing is required.", log_bytes!(self.context.channel_id()));
                                pending_forward_status = create_pending_htlc_status(self, pending_forward_status, 0x1000|7);
                        }
                } else {
                        // Check that they won't violate our local required channel reserve by adding this HTLC.
                        let htlc_candidate = HTLCCandidate::new(msg.amount_msat, HTLCInitiator::RemoteOffered);
-                       let local_commit_tx_fee_msat = self.next_local_commit_tx_fee_msat(htlc_candidate, None);
+                       let local_commit_tx_fee_msat = self.context.next_local_commit_tx_fee_msat(htlc_candidate, None);
                        if self.context.value_to_self_msat < self.context.counterparty_selected_channel_reserve_satoshis.unwrap() * 1000 + local_commit_tx_fee_msat {
                                return Err(ChannelError::Close("Cannot accept HTLC that would put our balance under counterparty-announced channel reserve value".to_owned()));
                        }
@@ -3334,11 +3591,11 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                        return Err(ChannelError::Close("Peer sent commitment_signed after we'd started exchanging closing_signeds".to_owned()));
                }
 
-               let funding_script = self.get_funding_redeemscript();
+               let funding_script = self.context.get_funding_redeemscript();
 
-               let keys = self.build_holder_transaction_keys(self.context.cur_holder_commitment_transaction_number);
+               let keys = self.context.build_holder_transaction_keys(self.context.cur_holder_commitment_transaction_number);
 
-               let commitment_stats = self.build_commitment_transaction(self.context.cur_holder_commitment_transaction_number, &keys, true, false, logger);
+               let commitment_stats = self.context.build_commitment_transaction(self.context.cur_holder_commitment_transaction_number, &keys, true, false, logger);
                let commitment_txid = {
                        let trusted_tx = commitment_stats.tx.trust();
                        let bitcoin_tx = trusted_tx.built_transaction();
@@ -3346,9 +3603,9 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
 
                        log_trace!(logger, "Checking commitment tx signature {} by key {} against tx {} (sighash {}) with redeemscript {} in channel {}",
                                log_bytes!(msg.signature.serialize_compact()[..]),
-                               log_bytes!(self.counterparty_funding_pubkey().serialize()), encode::serialize_hex(&bitcoin_tx.transaction),
-                               log_bytes!(sighash[..]), encode::serialize_hex(&funding_script), log_bytes!(self.channel_id()));
-                       if let Err(_) = self.context.secp_ctx.verify_ecdsa(&sighash, &msg.signature, &self.counterparty_funding_pubkey()) {
+                               log_bytes!(self.context.counterparty_funding_pubkey().serialize()), encode::serialize_hex(&bitcoin_tx.transaction),
+                               log_bytes!(sighash[..]), encode::serialize_hex(&funding_script), log_bytes!(self.context.channel_id()));
+                       if let Err(_) = self.context.secp_ctx.verify_ecdsa(&sighash, &msg.signature, &self.context.counterparty_funding_pubkey()) {
                                return Err(ChannelError::Close("Invalid commitment tx signature from peer".to_owned()));
                        }
                        bitcoin_tx.txid
@@ -3409,7 +3666,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                for (idx, (htlc, mut source_opt)) in htlcs_cloned.drain(..).enumerate() {
                        if let Some(_) = htlc.transaction_output_index {
                                let htlc_tx = chan_utils::build_htlc_transaction(&commitment_txid, commitment_stats.feerate_per_kw,
-                                       self.get_counterparty_selected_contest_delay().unwrap(), &htlc, self.context.opt_anchors(),
+                                       self.context.get_counterparty_selected_contest_delay().unwrap(), &htlc, self.context.opt_anchors(),
                                        false, &keys.broadcaster_delayed_payment_key, &keys.revocation_key);
 
                                let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, self.context.opt_anchors(), &keys);
@@ -3417,7 +3674,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                                let htlc_sighash = hash_to_message!(&sighash::SighashCache::new(&htlc_tx).segwit_signature_hash(0, &htlc_redeemscript, htlc.amount_msat / 1000, htlc_sighashtype).unwrap()[..]);
                                log_trace!(logger, "Checking HTLC tx signature {} by key {} against tx {} (sighash {}) with redeemscript {} in channel {}.",
                                        log_bytes!(msg.htlc_signatures[idx].serialize_compact()[..]), log_bytes!(keys.countersignatory_htlc_key.serialize()),
-                                       encode::serialize_hex(&htlc_tx), log_bytes!(htlc_sighash[..]), encode::serialize_hex(&htlc_redeemscript), log_bytes!(self.channel_id()));
+                                       encode::serialize_hex(&htlc_tx), log_bytes!(htlc_sighash[..]), encode::serialize_hex(&htlc_redeemscript), log_bytes!(self.context.channel_id()));
                                if let Err(_) = self.context.secp_ctx.verify_ecdsa(&htlc_sighash, &msg.htlc_signatures[idx], &keys.countersignatory_htlc_key) {
                                        return Err(ChannelError::Close("Invalid HTLC tx signature from peer".to_owned()));
                                }
@@ -3439,8 +3696,8 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                        commitment_stats.tx,
                        msg.signature,
                        msg.htlc_signatures.clone(),
-                       &self.get_holder_pubkeys().funding_pubkey,
-                       self.counterparty_funding_pubkey()
+                       &self.context.get_holder_pubkeys().funding_pubkey,
+                       self.context.counterparty_funding_pubkey()
                );
 
                self.context.holder_signer.validate_holder_commitment(&holder_commitment_tx, commitment_stats.preimages)
@@ -3537,7 +3794,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                } else { false };
 
                log_debug!(logger, "Received valid commitment_signed from peer in channel {}, updating HTLC state and responding with{} a revoke_and_ack.",
-                       log_bytes!(self.channel_id()), if need_commitment_signed { " our own commitment_signed and" } else { "" });
+                       log_bytes!(self.context.channel_id()), if need_commitment_signed { " our own commitment_signed and" } else { "" });
                self.monitor_updating_paused(true, need_commitment_signed, false, Vec::new(), Vec::new(), Vec::new());
                return Ok(self.push_ret_blockable_mon_update(monitor_update));
        }
@@ -3558,7 +3815,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                assert_eq!(self.context.channel_state & ChannelState::MonitorUpdateInProgress as u32, 0);
                if self.context.holding_cell_htlc_updates.len() != 0 || self.context.holding_cell_update_fee.is_some() {
                        log_trace!(logger, "Freeing holding cell with {} HTLC updates{} in channel {}", self.context.holding_cell_htlc_updates.len(),
-                               if self.context.holding_cell_update_fee.is_some() { " and a fee update" } else { "" }, log_bytes!(self.channel_id()));
+                               if self.context.holding_cell_update_fee.is_some() { " and a fee update" } else { "" }, log_bytes!(self.context.channel_id()));
 
                        let mut monitor_update = ChannelMonitorUpdate {
                                update_id: self.context.latest_monitor_update_id + 1, // We don't increment this yet!
@@ -3585,7 +3842,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                                                                match e {
                                                                        ChannelError::Ignore(ref msg) => {
                                                                                log_info!(logger, "Failed to send HTLC with payment_hash {} due to {} in channel {}",
-                                                                                       log_bytes!(payment_hash.0), msg, log_bytes!(self.channel_id()));
+                                                                                       log_bytes!(payment_hash.0), msg, log_bytes!(self.context.channel_id()));
                                                                                // If we fail to send here, then this HTLC should
                                                                                // be failed backwards. Failing to send here
                                                                                // indicates that this HTLC may keep being put back
@@ -3650,7 +3907,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                        monitor_update.updates.append(&mut additional_update.updates);
 
                        log_debug!(logger, "Freeing holding cell in channel {} resulted in {}{} HTLCs added, {} HTLCs fulfilled, and {} HTLCs failed.",
-                               log_bytes!(self.channel_id()), if update_fee.is_some() { "a fee update, " } else { "" },
+                               log_bytes!(self.context.channel_id()), if update_fee.is_some() { "a fee update, " } else { "" },
                                update_add_htlcs.len(), update_fulfill_htlcs.len(), update_fail_htlcs.len());
 
                        self.monitor_updating_paused(false, true, false, Vec::new(), Vec::new(), Vec::new());
@@ -3733,7 +3990,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                        self.context.announcement_sigs_state = AnnouncementSigsState::PeerReceived;
                }
 
-               log_trace!(logger, "Updating HTLCs on receipt of RAA in channel {}...", log_bytes!(self.channel_id()));
+               log_trace!(logger, "Updating HTLCs on receipt of RAA in channel {}...", log_bytes!(self.context.channel_id()));
                let mut to_forward_infos = Vec::new();
                let mut revoked_htlcs = Vec::new();
                let mut finalized_claimed_htlcs = Vec::new();
@@ -3862,7 +4119,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                        self.context.monitor_pending_forwards.append(&mut to_forward_infos);
                        self.context.monitor_pending_failures.append(&mut revoked_htlcs);
                        self.context.monitor_pending_finalized_fulfills.append(&mut finalized_claimed_htlcs);
-                       log_debug!(logger, "Received a valid revoke_and_ack for channel {} but awaiting a monitor update resolution to reply.", log_bytes!(self.channel_id()));
+                       log_debug!(logger, "Received a valid revoke_and_ack for channel {} but awaiting a monitor update resolution to reply.", log_bytes!(self.context.channel_id()));
                        return Ok((Vec::new(), self.push_ret_blockable_mon_update(monitor_update)));
                }
 
@@ -3887,11 +4144,11 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                                        monitor_update.updates.append(&mut additional_update.updates);
 
                                        log_debug!(logger, "Received a valid revoke_and_ack for channel {}. Responding with a commitment update with {} HTLCs failed.",
-                                               log_bytes!(self.channel_id()), update_fail_htlcs.len() + update_fail_malformed_htlcs.len());
+                                               log_bytes!(self.context.channel_id()), update_fail_htlcs.len() + update_fail_malformed_htlcs.len());
                                        self.monitor_updating_paused(false, true, false, to_forward_infos, revoked_htlcs, finalized_claimed_htlcs);
                                        Ok((htlcs_to_fail, self.push_ret_blockable_mon_update(monitor_update)))
                                } else {
-                                       log_debug!(logger, "Received a valid revoke_and_ack for channel {} with no reply necessary.", log_bytes!(self.channel_id()));
+                                       log_debug!(logger, "Received a valid revoke_and_ack for channel {} with no reply necessary.", log_bytes!(self.context.channel_id()));
                                        self.monitor_updating_paused(false, false, false, to_forward_infos, revoked_htlcs, finalized_claimed_htlcs);
                                        Ok((htlcs_to_fail, self.push_ret_blockable_mon_update(monitor_update)))
                                }
@@ -3926,11 +4183,11 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                }
 
                // Before proposing a feerate update, check that we can actually afford the new fee.
-               let inbound_stats = self.get_inbound_pending_htlc_stats(Some(feerate_per_kw));
-               let outbound_stats = self.get_outbound_pending_htlc_stats(Some(feerate_per_kw));
-               let keys = self.build_holder_transaction_keys(self.context.cur_holder_commitment_transaction_number);
-               let commitment_stats = self.build_commitment_transaction(self.context.cur_holder_commitment_transaction_number, &keys, true, true, logger);
-               let buffer_fee_msat = Channel::<Signer>::commit_tx_fee_sat(feerate_per_kw, commitment_stats.num_nondust_htlcs + outbound_stats.on_holder_tx_holding_cell_htlcs_count as usize + CONCURRENT_INBOUND_HTLC_FEE_BUFFER as usize, self.context.opt_anchors()) * 1000;
+               let inbound_stats = self.context.get_inbound_pending_htlc_stats(Some(feerate_per_kw));
+               let outbound_stats = self.context.get_outbound_pending_htlc_stats(Some(feerate_per_kw));
+               let keys = self.context.build_holder_transaction_keys(self.context.cur_holder_commitment_transaction_number);
+               let commitment_stats = self.context.build_commitment_transaction(self.context.cur_holder_commitment_transaction_number, &keys, true, true, logger);
+               let buffer_fee_msat = commit_tx_fee_sat(feerate_per_kw, commitment_stats.num_nondust_htlcs + outbound_stats.on_holder_tx_holding_cell_htlcs_count as usize + CONCURRENT_INBOUND_HTLC_FEE_BUFFER as usize, self.context.opt_anchors()) * 1000;
                let holder_balance_msat = commitment_stats.local_balance_msat - outbound_stats.holding_cell_msat;
                if holder_balance_msat < buffer_fee_msat  + self.context.counterparty_selected_channel_reserve_satoshis.unwrap() * 1000 {
                        //TODO: auto-close after a number of failures?
@@ -3941,11 +4198,11 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                // Note, we evaluate pending htlc "preemptive" trimmed-to-dust threshold at the proposed `feerate_per_kw`.
                let holder_tx_dust_exposure = inbound_stats.on_holder_tx_dust_exposure_msat + outbound_stats.on_holder_tx_dust_exposure_msat;
                let counterparty_tx_dust_exposure = inbound_stats.on_counterparty_tx_dust_exposure_msat + outbound_stats.on_counterparty_tx_dust_exposure_msat;
-               if holder_tx_dust_exposure > self.get_max_dust_htlc_exposure_msat() {
+               if holder_tx_dust_exposure > self.context.get_max_dust_htlc_exposure_msat() {
                        log_debug!(logger, "Cannot afford to send new feerate at {} without infringing max dust htlc exposure", feerate_per_kw);
                        return None;
                }
-               if counterparty_tx_dust_exposure > self.get_max_dust_htlc_exposure_msat() {
+               if counterparty_tx_dust_exposure > self.context.get_max_dust_htlc_exposure_msat() {
                        log_debug!(logger, "Cannot afford to send new feerate at {} without infringing max dust htlc exposure", feerate_per_kw);
                        return None;
                }
@@ -4043,7 +4300,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                self.context.sent_message_awaiting_response = None;
 
                self.context.channel_state |= ChannelState::PeerDisconnected as u32;
-               log_trace!(logger, "Peer disconnection resulted in {} remote-announced HTLC drops on channel {}", inbound_drop_count, log_bytes!(self.channel_id()));
+               log_trace!(logger, "Peer disconnection resulted in {} remote-announced HTLC drops on channel {}", inbound_drop_count, log_bytes!(self.context.channel_id()));
        }
 
        /// Indicates that a ChannelMonitor update is in progress and has not yet been fully persisted.
@@ -4116,7 +4373,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                        self.context.monitor_pending_channel_ready = false;
                        let next_per_commitment_point = self.context.holder_signer.get_per_commitment_point(self.context.cur_holder_commitment_transaction_number, &self.context.secp_ctx);
                        Some(msgs::ChannelReady {
-                               channel_id: self.channel_id(),
+                               channel_id: self.context.channel_id(),
                                next_per_commitment_point,
                                short_channel_id_alias: Some(self.context.outbound_scid_alias),
                        })
@@ -4152,7 +4409,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                self.context.monitor_pending_commitment_signed = false;
                let order = self.context.resend_order.clone();
                log_debug!(logger, "Restored monitor updating in channel {} resulting in {}{} commitment update and {} RAA, with {} first",
-                       log_bytes!(self.channel_id()), if funding_broadcastable.is_some() { "a funding broadcastable, " } else { "" },
+                       log_bytes!(self.context.channel_id()), if funding_broadcastable.is_some() { "a funding broadcastable, " } else { "" },
                        if commitment_update.is_some() { "a" } else { "no" }, if raa.is_some() { "an" } else { "no" },
                        match order { RAACommitmentOrder::CommitmentFirst => "commitment", RAACommitmentOrder::RevokeAndACKFirst => "RAA"});
                MonitorRestoreUpdates {
@@ -4170,7 +4427,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                        return Err(ChannelError::Close("Peer sent update_fee when we needed a channel_reestablish".to_owned()));
                }
                Channel::<Signer>::check_remote_fee(fee_estimator, msg.feerate_per_kw, Some(self.context.feerate_per_kw), logger)?;
-               let feerate_over_dust_buffer = msg.feerate_per_kw > self.get_dust_buffer_feerate(None);
+               let feerate_over_dust_buffer = msg.feerate_per_kw > self.context.get_dust_buffer_feerate(None);
 
                self.context.pending_update_fee = Some((msg.feerate_per_kw, FeeUpdateState::RemoteAnnounced));
                self.context.update_time_counter += 1;
@@ -4178,15 +4435,15 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                // `get_dust_buffer_feerate` considers the `pending_update_fee` status), check that we
                // won't be pushed over our dust exposure limit by the feerate increase.
                if feerate_over_dust_buffer {
-                       let inbound_stats = self.get_inbound_pending_htlc_stats(None);
-                       let outbound_stats = self.get_outbound_pending_htlc_stats(None);
+                       let inbound_stats = self.context.get_inbound_pending_htlc_stats(None);
+                       let outbound_stats = self.context.get_outbound_pending_htlc_stats(None);
                        let holder_tx_dust_exposure = inbound_stats.on_holder_tx_dust_exposure_msat + outbound_stats.on_holder_tx_dust_exposure_msat;
                        let counterparty_tx_dust_exposure = inbound_stats.on_counterparty_tx_dust_exposure_msat + outbound_stats.on_counterparty_tx_dust_exposure_msat;
-                       if holder_tx_dust_exposure > self.get_max_dust_htlc_exposure_msat() {
+                       if holder_tx_dust_exposure > self.context.get_max_dust_htlc_exposure_msat() {
                                return Err(ChannelError::Close(format!("Peer sent update_fee with a feerate ({}) which may over-expose us to dust-in-flight on our own transactions (totaling {} msat)",
                                        msg.feerate_per_kw, holder_tx_dust_exposure)));
                        }
-                       if counterparty_tx_dust_exposure > self.get_max_dust_htlc_exposure_msat() {
+                       if counterparty_tx_dust_exposure > self.context.get_max_dust_htlc_exposure_msat() {
                                return Err(ChannelError::Close(format!("Peer sent update_fee with a feerate ({}) which may over-expose us to dust-in-flight on our counterparty's transactions (totaling {} msat)",
                                        msg.feerate_per_kw, counterparty_tx_dust_exposure)));
                        }
@@ -4215,7 +4472,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                for htlc in self.context.pending_outbound_htlcs.iter() {
                        if let &OutboundHTLCState::LocalAnnounced(ref onion_packet) = &htlc.state {
                                update_add_htlcs.push(msgs::UpdateAddHTLC {
-                                       channel_id: self.channel_id(),
+                                       channel_id: self.context.channel_id(),
                                        htlc_id: htlc.htlc_id,
                                        amount_msat: htlc.amount_msat,
                                        payment_hash: htlc.payment_hash,
@@ -4230,14 +4487,14 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                                match reason {
                                        &InboundHTLCRemovalReason::FailRelay(ref err_packet) => {
                                                update_fail_htlcs.push(msgs::UpdateFailHTLC {
-                                                       channel_id: self.channel_id(),
+                                                       channel_id: self.context.channel_id(),
                                                        htlc_id: htlc.htlc_id,
                                                        reason: err_packet.clone()
                                                });
                                        },
                                        &InboundHTLCRemovalReason::FailMalformed((ref sha256_of_onion, ref failure_code)) => {
                                                update_fail_malformed_htlcs.push(msgs::UpdateFailMalformedHTLC {
-                                                       channel_id: self.channel_id(),
+                                                       channel_id: self.context.channel_id(),
                                                        htlc_id: htlc.htlc_id,
                                                        sha256_of_onion: sha256_of_onion.clone(),
                                                        failure_code: failure_code.clone(),
@@ -4245,7 +4502,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                                        },
                                        &InboundHTLCRemovalReason::Fulfill(ref payment_preimage) => {
                                                update_fulfill_htlcs.push(msgs::UpdateFulfillHTLC {
-                                                       channel_id: self.channel_id(),
+                                                       channel_id: self.context.channel_id(),
                                                        htlc_id: htlc.htlc_id,
                                                        payment_preimage: payment_preimage.clone(),
                                                });
@@ -4256,13 +4513,13 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
 
                let update_fee = if self.context.is_outbound() && self.context.pending_update_fee.is_some() {
                        Some(msgs::UpdateFee {
-                               channel_id: self.channel_id(),
+                               channel_id: self.context.channel_id(),
                                feerate_per_kw: self.context.pending_update_fee.unwrap().0,
                        })
                } else { None };
 
                log_trace!(logger, "Regenerated latest commitment update in channel {} with{} {} update_adds, {} update_fulfills, {} update_fails, and {} update_fail_malformeds",
-                               log_bytes!(self.channel_id()), if update_fee.is_some() { " update_fee," } else { "" },
+                               log_bytes!(self.context.channel_id()), if update_fee.is_some() { " update_fee," } else { "" },
                                update_add_htlcs.len(), update_fulfill_htlcs.len(), update_fail_htlcs.len(), update_fail_malformed_htlcs.len());
                msgs::CommitmentUpdate {
                        update_add_htlcs, update_fulfill_htlcs, update_fail_htlcs, update_fail_malformed_htlcs, update_fee,
@@ -4366,7 +4623,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                        let next_per_commitment_point = self.context.holder_signer.get_per_commitment_point(self.context.cur_holder_commitment_transaction_number, &self.context.secp_ctx);
                        return Ok(ReestablishResponses {
                                channel_ready: Some(msgs::ChannelReady {
-                                       channel_id: self.channel_id(),
+                                       channel_id: self.context.channel_id(),
                                        next_per_commitment_point,
                                        short_channel_id_alias: Some(self.context.outbound_scid_alias),
                                }),
@@ -4405,7 +4662,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                        // We should never have to worry about MonitorUpdateInProgress resending ChannelReady
                        let next_per_commitment_point = self.context.holder_signer.get_per_commitment_point(self.context.cur_holder_commitment_transaction_number, &self.context.secp_ctx);
                        Some(msgs::ChannelReady {
-                               channel_id: self.channel_id(),
+                               channel_id: self.context.channel_id(),
                                next_per_commitment_point,
                                short_channel_id_alias: Some(self.context.outbound_scid_alias),
                        })
@@ -4413,9 +4670,9 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
 
                if msg.next_local_commitment_number == next_counterparty_commitment_number {
                        if required_revoke.is_some() {
-                               log_debug!(logger, "Reconnected channel {} with only lost outbound RAA", log_bytes!(self.channel_id()));
+                               log_debug!(logger, "Reconnected channel {} with only lost outbound RAA", log_bytes!(self.context.channel_id()));
                        } else {
-                               log_debug!(logger, "Reconnected channel {} with no loss", log_bytes!(self.channel_id()));
+                               log_debug!(logger, "Reconnected channel {} with no loss", log_bytes!(self.context.channel_id()));
                        }
 
                        Ok(ReestablishResponses {
@@ -4426,9 +4683,9 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                        })
                } else if msg.next_local_commitment_number == next_counterparty_commitment_number - 1 {
                        if required_revoke.is_some() {
-                               log_debug!(logger, "Reconnected channel {} with lost outbound RAA and lost remote commitment tx", log_bytes!(self.channel_id()));
+                               log_debug!(logger, "Reconnected channel {} with lost outbound RAA and lost remote commitment tx", log_bytes!(self.context.channel_id()));
                        } else {
-                               log_debug!(logger, "Reconnected channel {} with only lost remote commitment tx", log_bytes!(self.channel_id()));
+                               log_debug!(logger, "Reconnected channel {} with only lost remote commitment tx", log_bytes!(self.context.channel_id()));
                        }
 
                        if self.context.channel_state & (ChannelState::MonitorUpdateInProgress as u32) != 0 {
@@ -4695,8 +4952,8 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
 
                tx.input[0].witness.push(Vec::new()); // First is the multisig dummy
 
-               let funding_key = self.get_holder_pubkeys().funding_pubkey.serialize();
-               let counterparty_funding_key = self.counterparty_funding_pubkey().serialize();
+               let funding_key = self.context.get_holder_pubkeys().funding_pubkey.serialize();
+               let counterparty_funding_key = self.context.counterparty_funding_pubkey().serialize();
                let mut holder_sig = sig.serialize_der().to_vec();
                holder_sig.push(EcdsaSighashType::All as u8);
                let mut cp_sig = counterparty_sig.serialize_der().to_vec();
@@ -4709,7 +4966,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                        tx.input[0].witness.push(holder_sig);
                }
 
-               tx.input[0].witness.push(self.get_funding_redeemscript().into_bytes());
+               tx.input[0].witness.push(self.context.get_funding_redeemscript().into_bytes());
                tx
        }
 
@@ -4740,21 +4997,21 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                        return Ok((None, None));
                }
 
-               let funding_redeemscript = self.get_funding_redeemscript();
+               let funding_redeemscript = self.context.get_funding_redeemscript();
                let (mut closing_tx, used_total_fee) = self.build_closing_transaction(msg.fee_satoshis, false);
                if used_total_fee != msg.fee_satoshis {
                        return Err(ChannelError::Close(format!("Remote sent us a closing_signed with a fee other than the value they can claim. Fee in message: {}. Actual closing tx fee: {}", msg.fee_satoshis, used_total_fee)));
                }
                let sighash = closing_tx.trust().get_sighash_all(&funding_redeemscript, self.context.channel_value_satoshis);
 
-               match self.context.secp_ctx.verify_ecdsa(&sighash, &msg.signature, &self.get_counterparty_pubkeys().funding_pubkey) {
+               match self.context.secp_ctx.verify_ecdsa(&sighash, &msg.signature, &self.context.get_counterparty_pubkeys().funding_pubkey) {
                        Ok(_) => {},
                        Err(_e) => {
                                // The remote end may have decided to revoke their output due to inconsistent dust
                                // limits, so check for that case by re-checking the signature here.
                                closing_tx = self.build_closing_transaction(msg.fee_satoshis, true).0;
                                let sighash = closing_tx.trust().get_sighash_all(&funding_redeemscript, self.context.channel_value_satoshis);
-                               secp_check!(self.context.secp_ctx.verify_ecdsa(&sighash, &msg.signature, self.counterparty_funding_pubkey()), "Invalid closing tx signature from peer".to_owned());
+                               secp_check!(self.context.secp_ctx.verify_ecdsa(&sighash, &msg.signature, self.context.counterparty_funding_pubkey()), "Invalid closing tx signature from peer".to_owned());
                        },
                };
 
@@ -4865,224 +5122,6 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                }
        }
 
-       // Public utilities:
-
-       pub fn channel_id(&self) -> [u8; 32] {
-               self.context.channel_id
-       }
-
-       // Return the `temporary_channel_id` used during channel establishment.
-       //
-       // Will return `None` for channels created prior to LDK version 0.0.115.
-       pub fn temporary_channel_id(&self) -> Option<[u8; 32]> {
-               self.context.temporary_channel_id
-       }
-
-       pub fn minimum_depth(&self) -> Option<u32> {
-               self.context.minimum_depth
-       }
-
-       /// Gets the "user_id" value passed into the construction of this channel. It has no special
-       /// meaning and exists only to allow users to have a persistent identifier of a channel.
-       pub fn get_user_id(&self) -> u128 {
-               self.context.user_id
-       }
-
-       /// Gets the channel's type
-       pub fn get_channel_type(&self) -> &ChannelTypeFeatures {
-               &self.context.channel_type
-       }
-
-       /// Guaranteed to be Some after both ChannelReady messages have been exchanged (and, thus,
-       /// is_usable() returns true).
-       /// Allowed in any state (including after shutdown)
-       pub fn get_short_channel_id(&self) -> Option<u64> {
-               self.context.short_channel_id
-       }
-
-       /// Allowed in any state (including after shutdown)
-       pub fn latest_inbound_scid_alias(&self) -> Option<u64> {
-               self.context.latest_inbound_scid_alias
-       }
-
-       /// Allowed in any state (including after shutdown)
-       pub fn outbound_scid_alias(&self) -> u64 {
-               self.context.outbound_scid_alias
-       }
-       /// Only allowed immediately after deserialization if get_outbound_scid_alias returns 0,
-       /// indicating we were written by LDK prior to 0.0.106 which did not set outbound SCID aliases.
-       pub fn set_outbound_scid_alias(&mut self, outbound_scid_alias: u64) {
-               assert_eq!(self.context.outbound_scid_alias, 0);
-               self.context.outbound_scid_alias = outbound_scid_alias;
-       }
-
-       /// Returns the funding_txo we either got from our peer, or were given by
-       /// get_outbound_funding_created.
-       pub fn get_funding_txo(&self) -> Option<OutPoint> {
-               self.context.channel_transaction_parameters.funding_outpoint
-       }
-
-       /// Returns the block hash in which our funding transaction was confirmed.
-       pub fn get_funding_tx_confirmed_in(&self) -> Option<BlockHash> {
-               self.context.funding_tx_confirmed_in
-       }
-
-       /// Returns the current number of confirmations on the funding transaction.
-       pub fn get_funding_tx_confirmations(&self, height: u32) -> u32 {
-               if self.context.funding_tx_confirmation_height == 0 {
-                       // We either haven't seen any confirmation yet, or observed a reorg.
-                       return 0;
-               }
-
-               height.checked_sub(self.context.funding_tx_confirmation_height).map_or(0, |c| c + 1)
-       }
-
-       fn get_holder_selected_contest_delay(&self) -> u16 {
-               self.context.channel_transaction_parameters.holder_selected_contest_delay
-       }
-
-       fn get_holder_pubkeys(&self) -> &ChannelPublicKeys {
-               &self.context.channel_transaction_parameters.holder_pubkeys
-       }
-
-       pub fn get_counterparty_selected_contest_delay(&self) -> Option<u16> {
-               self.context.channel_transaction_parameters.counterparty_parameters
-                       .as_ref().map(|params| params.selected_contest_delay)
-       }
-
-       fn get_counterparty_pubkeys(&self) -> &ChannelPublicKeys {
-               &self.context.channel_transaction_parameters.counterparty_parameters.as_ref().unwrap().pubkeys
-       }
-
-       /// Allowed in any state (including after shutdown)
-       pub fn get_counterparty_node_id(&self) -> PublicKey {
-               self.context.counterparty_node_id
-       }
-
-       /// Allowed in any state (including after shutdown)
-       pub fn get_holder_htlc_minimum_msat(&self) -> u64 {
-               self.context.holder_htlc_minimum_msat
-       }
-
-       /// Allowed in any state (including after shutdown), but will return none before TheirInitSent
-       pub fn get_holder_htlc_maximum_msat(&self) -> Option<u64> {
-               self.get_htlc_maximum_msat(self.context.holder_max_htlc_value_in_flight_msat)
-       }
-
-       /// Allowed in any state (including after shutdown)
-       pub fn get_announced_htlc_max_msat(&self) -> u64 {
-               return cmp::min(
-                       // Upper bound by capacity. We make it a bit less than full capacity to prevent attempts
-                       // to use full capacity. This is an effort to reduce routing failures, because in many cases
-                       // channel might have been used to route very small values (either by honest users or as DoS).
-                       self.context.channel_value_satoshis * 1000 * 9 / 10,
-
-                       self.context.counterparty_max_htlc_value_in_flight_msat
-               );
-       }
-
-       /// Allowed in any state (including after shutdown)
-       pub fn get_counterparty_htlc_minimum_msat(&self) -> u64 {
-               self.context.counterparty_htlc_minimum_msat
-       }
-
-       /// Allowed in any state (including after shutdown), but will return none before TheirInitSent
-       pub fn get_counterparty_htlc_maximum_msat(&self) -> Option<u64> {
-               self.get_htlc_maximum_msat(self.context.counterparty_max_htlc_value_in_flight_msat)
-       }
-
-       fn get_htlc_maximum_msat(&self, party_max_htlc_value_in_flight_msat: u64) -> Option<u64> {
-               self.context.counterparty_selected_channel_reserve_satoshis.map(|counterparty_reserve| {
-                       let holder_reserve = self.context.holder_selected_channel_reserve_satoshis;
-                       cmp::min(
-                               (self.context.channel_value_satoshis - counterparty_reserve - holder_reserve) * 1000,
-                               party_max_htlc_value_in_flight_msat
-                       )
-               })
-       }
-
-       pub fn get_value_satoshis(&self) -> u64 {
-               self.context.channel_value_satoshis
-       }
-
-       pub fn get_fee_proportional_millionths(&self) -> u32 {
-               self.context.config.options.forwarding_fee_proportional_millionths
-       }
-
-       pub fn get_cltv_expiry_delta(&self) -> u16 {
-               cmp::max(self.context.config.options.cltv_expiry_delta, MIN_CLTV_EXPIRY_DELTA)
-       }
-
-       pub fn get_max_dust_htlc_exposure_msat(&self) -> u64 {
-               self.context.config.options.max_dust_htlc_exposure_msat
-       }
-
-       /// Returns the previous [`ChannelConfig`] applied to this channel, if any.
-       pub fn prev_config(&self) -> Option<ChannelConfig> {
-               self.context.prev_config.map(|prev_config| prev_config.0)
-       }
-
-       // Checks whether we should emit a `ChannelPending` event.
-       pub(crate) fn should_emit_channel_pending_event(&mut self) -> bool {
-               self.is_funding_initiated() && !self.context.channel_pending_event_emitted
-       }
-
-       // Returns whether we already emitted a `ChannelPending` event.
-       pub(crate) fn channel_pending_event_emitted(&self) -> bool {
-               self.context.channel_pending_event_emitted
-       }
-
-       // Remembers that we already emitted a `ChannelPending` event.
-       pub(crate) fn set_channel_pending_event_emitted(&mut self) {
-               self.context.channel_pending_event_emitted = true;
-       }
-
-       // Checks whether we should emit a `ChannelReady` event.
-       pub(crate) fn should_emit_channel_ready_event(&mut self) -> bool {
-               self.context.is_usable() && !self.context.channel_ready_event_emitted
-       }
-
-       // Remembers that we already emitted a `ChannelReady` event.
-       pub(crate) fn set_channel_ready_event_emitted(&mut self) {
-               self.context.channel_ready_event_emitted = true;
-       }
-
-       /// Tracks the number of ticks elapsed since the previous [`ChannelConfig`] was updated. Once
-       /// [`EXPIRE_PREV_CONFIG_TICKS`] is reached, the previous config is considered expired and will
-       /// no longer be considered when forwarding HTLCs.
-       pub fn maybe_expire_prev_config(&mut self) {
-               if self.context.prev_config.is_none() {
-                       return;
-               }
-               let prev_config = self.context.prev_config.as_mut().unwrap();
-               prev_config.1 += 1;
-               if prev_config.1 == EXPIRE_PREV_CONFIG_TICKS {
-                       self.context.prev_config = None;
-               }
-       }
-
-       /// Returns the current [`ChannelConfig`] applied to the channel.
-       pub fn config(&self) -> ChannelConfig {
-               self.context.config.options
-       }
-
-       /// Updates the channel's config. A bool is returned indicating whether the config update
-       /// applied resulted in a new ChannelUpdate message.
-       pub fn update_config(&mut self, config: &ChannelConfig) -> bool {
-               let did_channel_update =
-                       self.context.config.options.forwarding_fee_proportional_millionths != config.forwarding_fee_proportional_millionths ||
-                       self.context.config.options.forwarding_fee_base_msat != config.forwarding_fee_base_msat ||
-                       self.context.config.options.cltv_expiry_delta != config.cltv_expiry_delta;
-               if did_channel_update {
-                       self.context.prev_config = Some((self.context.config.options, 0));
-                       // Update the counter, which backs the ChannelUpdate timestamp, to allow the relay
-                       // policy change to propagate throughout the network.
-                       self.context.update_time_counter += 1;
-               }
-               self.context.config.options = *config;
-               did_channel_update
-       }
-
        fn internal_htlc_satisfies_config(
                &self, htlc: &msgs::UpdateAddHTLC, amt_to_forward: u64, outgoing_cltv_value: u32, config: &ChannelConfig,
        ) -> Result<(), (&'static str, u16)> {
@@ -5110,9 +5149,9 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
        pub fn htlc_satisfies_config(
                &self, htlc: &msgs::UpdateAddHTLC, amt_to_forward: u64, outgoing_cltv_value: u32,
        ) -> Result<(), (&'static str, u16)> {
-               self.internal_htlc_satisfies_config(&htlc, amt_to_forward, outgoing_cltv_value, &self.config())
+               self.internal_htlc_satisfies_config(&htlc, amt_to_forward, outgoing_cltv_value, &self.context.config())
                        .or_else(|err| {
-                               if let Some(prev_config) = self.prev_config() {
+                               if let Some(prev_config) = self.context.prev_config() {
                                        self.internal_htlc_satisfies_config(htlc, amt_to_forward, outgoing_cltv_value, &prev_config)
                                } else {
                                        Err(err)
@@ -5120,28 +5159,6 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                        })
        }
 
-       pub fn get_feerate_sat_per_1000_weight(&self) -> u32 {
-               self.context.feerate_per_kw
-       }
-
-       pub fn get_dust_buffer_feerate(&self, outbound_feerate_update: Option<u32>) -> u32 {
-               // When calculating our exposure to dust HTLCs, we assume that the channel feerate
-               // may, at any point, increase by at least 10 sat/vB (i.e 2530 sat/kWU) or 25%,
-               // whichever is higher. This ensures that we aren't suddenly exposed to significantly
-               // more dust balance if the feerate increases when we have several HTLCs pending
-               // which are near the dust limit.
-               let mut feerate_per_kw = self.context.feerate_per_kw;
-               // If there's a pending update fee, use it to ensure we aren't under-estimating
-               // potential feerate updates coming soon.
-               if let Some((feerate, _)) = self.context.pending_update_fee {
-                       feerate_per_kw = cmp::max(feerate_per_kw, feerate);
-               }
-               if let Some(feerate) = outbound_feerate_update {
-                       feerate_per_kw = cmp::max(feerate_per_kw, feerate);
-               }
-               cmp::max(2530, feerate_per_kw * 1250 / 1000)
-       }
-
        pub fn get_cur_holder_commitment_transaction_number(&self) -> u64 {
                self.context.cur_holder_commitment_transaction_number + 1
        }
@@ -5250,11 +5267,6 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                        .filter_map(|upd| if upd.blocked { None } else { Some(&upd.update) })
        }
 
-       /// Returns true if funding_created was sent/received.
-       pub fn is_funding_initiated(&self) -> bool {
-               self.context.channel_state >= ChannelState::FundingSent as u32
-       }
-
        /// Returns true if the channel is awaiting the persistence of the initial ChannelMonitor.
        /// If the channel is outbound, this implies we have not yet broadcasted the funding
        /// transaction. If the channel is inbound, this implies simply that the channel has not
@@ -5397,14 +5409,14 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                NS::Target: NodeSigner,
                L::Target: Logger
        {
-               if let Some(funding_txo) = self.get_funding_txo() {
+               if let Some(funding_txo) = self.context.get_funding_txo() {
                        for &(index_in_block, tx) in txdata.iter() {
                                // Check if the transaction is the expected funding transaction, and if it is,
                                // check that it pays the right amount to the right script.
                                if self.context.funding_tx_confirmation_height == 0 {
                                        if tx.txid() == funding_txo.txid {
                                                let txo_idx = funding_txo.index as usize;
-                                               if txo_idx >= tx.output.len() || tx.output[txo_idx].script_pubkey != self.get_funding_redeemscript().to_v0_p2wsh() ||
+                                               if txo_idx >= tx.output.len() || tx.output[txo_idx].script_pubkey != self.context.get_funding_redeemscript().to_v0_p2wsh() ||
                                                                tx.output[txo_idx].value != self.context.channel_value_satoshis {
                                                        if self.context.is_outbound() {
                                                                // If we generated the funding transaction and it doesn't match what it
@@ -5448,7 +5460,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                                }
                                for inp in tx.input.iter() {
                                        if inp.previous_output == funding_txo.into_bitcoin_outpoint() {
-                                               log_info!(logger, "Detected channel-closing tx {} spending {}:{}, closing channel {}", tx.txid(), inp.previous_output.txid, inp.previous_output.vout, log_bytes!(self.channel_id()));
+                                               log_info!(logger, "Detected channel-closing tx {} spending {}:{}, closing channel {}", tx.txid(), inp.previous_output.txid, inp.previous_output.vout, log_bytes!(self.context.channel_id()));
                                                return Err(ClosureReason::CommitmentTxConfirmed);
                                        }
                                }
@@ -5597,7 +5609,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                }
 
                let first_per_commitment_point = self.context.holder_signer.get_per_commitment_point(self.context.cur_holder_commitment_transaction_number, &self.context.secp_ctx);
-               let keys = self.get_holder_pubkeys();
+               let keys = self.context.get_holder_pubkeys();
 
                msgs::OpenChannel {
                        chain_hash,
@@ -5609,7 +5621,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                        channel_reserve_satoshis: self.context.holder_selected_channel_reserve_satoshis,
                        htlc_minimum_msat: self.context.holder_htlc_minimum_msat,
                        feerate_per_kw: self.context.feerate_per_kw as u32,
-                       to_self_delay: self.get_holder_selected_contest_delay(),
+                       to_self_delay: self.context.get_holder_selected_contest_delay(),
                        max_accepted_htlcs: self.context.holder_max_accepted_htlcs,
                        funding_pubkey: keys.funding_pubkey,
                        revocation_basepoint: keys.revocation_basepoint,
@@ -5667,7 +5679,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
        /// [`msgs::AcceptChannel`]: crate::ln::msgs::AcceptChannel
        fn generate_accept_channel_message(&self) -> msgs::AcceptChannel {
                let first_per_commitment_point = self.context.holder_signer.get_per_commitment_point(self.context.cur_holder_commitment_transaction_number, &self.context.secp_ctx);
-               let keys = self.get_holder_pubkeys();
+               let keys = self.context.get_holder_pubkeys();
 
                msgs::AcceptChannel {
                        temporary_channel_id: self.context.channel_id,
@@ -5676,7 +5688,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                        channel_reserve_satoshis: self.context.holder_selected_channel_reserve_satoshis,
                        htlc_minimum_msat: self.context.holder_htlc_minimum_msat,
                        minimum_depth: self.context.minimum_depth.unwrap(),
-                       to_self_delay: self.get_holder_selected_contest_delay(),
+                       to_self_delay: self.context.get_holder_selected_contest_delay(),
                        max_accepted_htlcs: self.context.holder_max_accepted_htlcs,
                        funding_pubkey: keys.funding_pubkey,
                        revocation_basepoint: keys.revocation_basepoint,
@@ -5705,8 +5717,8 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
 
        /// If an Err is returned, it is a ChannelError::Close (for get_outbound_funding_created)
        fn get_outbound_funding_created_signature<L: Deref>(&mut self, logger: &L) -> Result<Signature, ChannelError> where L::Target: Logger {
-               let counterparty_keys = self.build_remote_transaction_keys();
-               let counterparty_initial_commitment_tx = self.build_commitment_transaction(self.context.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, false, logger).tx;
+               let counterparty_keys = self.context.build_remote_transaction_keys();
+               let counterparty_initial_commitment_tx = self.context.build_commitment_transaction(self.context.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, false, logger).tx;
                Ok(self.context.holder_signer.sign_counterparty_commitment(&counterparty_initial_commitment_tx, Vec::new(), &self.context.secp_ctx)
                                .map_err(|_| ChannelError::Close("Failed to get signatures for new commitment_signed".to_owned()))?.0)
        }
@@ -5784,17 +5796,17 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
 
                let node_id = NodeId::from_pubkey(&node_signer.get_node_id(Recipient::Node)
                        .map_err(|_| ChannelError::Ignore("Failed to retrieve own public key".to_owned()))?);
-               let counterparty_node_id = NodeId::from_pubkey(&self.get_counterparty_node_id());
+               let counterparty_node_id = NodeId::from_pubkey(&self.context.get_counterparty_node_id());
                let were_node_one = node_id.as_slice() < counterparty_node_id.as_slice();
 
                let msg = msgs::UnsignedChannelAnnouncement {
                        features: channelmanager::provided_channel_features(&user_config),
                        chain_hash,
-                       short_channel_id: self.get_short_channel_id().unwrap(),
+                       short_channel_id: self.context.get_short_channel_id().unwrap(),
                        node_id_1: if were_node_one { node_id } else { counterparty_node_id },
                        node_id_2: if were_node_one { counterparty_node_id } else { node_id },
-                       bitcoin_key_1: NodeId::from_pubkey(if were_node_one { &self.get_holder_pubkeys().funding_pubkey } else { self.counterparty_funding_pubkey() }),
-                       bitcoin_key_2: NodeId::from_pubkey(if were_node_one { self.counterparty_funding_pubkey() } else { &self.get_holder_pubkeys().funding_pubkey }),
+                       bitcoin_key_1: NodeId::from_pubkey(if were_node_one { &self.context.get_holder_pubkeys().funding_pubkey } else { self.context.counterparty_funding_pubkey() }),
+                       bitcoin_key_2: NodeId::from_pubkey(if were_node_one { self.context.counterparty_funding_pubkey() } else { &self.context.get_holder_pubkeys().funding_pubkey }),
                        excess_data: Vec::new(),
                };
 
@@ -5826,7 +5838,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                        return None;
                }
 
-               log_trace!(logger, "Creating an announcement_signatures message for channel {}", log_bytes!(self.channel_id()));
+               log_trace!(logger, "Creating an announcement_signatures message for channel {}", log_bytes!(self.context.channel_id()));
                let announcement = match self.get_channel_announcement(node_signer, genesis_block_hash, user_config) {
                        Ok(a) => a,
                        Err(e) => {
@@ -5851,8 +5863,8 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                self.context.announcement_sigs_state = AnnouncementSigsState::MessageSent;
 
                Some(msgs::AnnouncementSignatures {
-                       channel_id: self.channel_id(),
-                       short_channel_id: self.get_short_channel_id().unwrap(),
+                       channel_id: self.context.channel_id(),
+                       short_channel_id: self.context.get_short_channel_id().unwrap(),
                        node_signature: our_node_sig,
                        bitcoin_signature: our_bitcoin_sig,
                })
@@ -5895,15 +5907,15 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
 
                let msghash = hash_to_message!(&Sha256d::hash(&announcement.encode()[..])[..]);
 
-               if self.context.secp_ctx.verify_ecdsa(&msghash, &msg.node_signature, &self.get_counterparty_node_id()).is_err() {
+               if self.context.secp_ctx.verify_ecdsa(&msghash, &msg.node_signature, &self.context.get_counterparty_node_id()).is_err() {
                        return Err(ChannelError::Close(format!(
                                "Bad announcement_signatures. Failed to verify node_signature. UnsignedChannelAnnouncement used for verification is {:?}. their_node_key is {:?}",
-                                &announcement, self.get_counterparty_node_id())));
+                                &announcement, self.context.get_counterparty_node_id())));
                }
-               if self.context.secp_ctx.verify_ecdsa(&msghash, &msg.bitcoin_signature, self.counterparty_funding_pubkey()).is_err() {
+               if self.context.secp_ctx.verify_ecdsa(&msghash, &msg.bitcoin_signature, self.context.counterparty_funding_pubkey()).is_err() {
                        return Err(ChannelError::Close(format!(
                                "Bad announcement_signatures. Failed to verify bitcoin_signature. UnsignedChannelAnnouncement used for verification is {:?}. their_bitcoin_key is ({:?})",
-                               &announcement, self.counterparty_funding_pubkey())));
+                               &announcement, self.context.counterparty_funding_pubkey())));
                }
 
                self.context.announcement_sigs = Some((msg.node_signature, msg.bitcoin_signature));
@@ -5948,15 +5960,15 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                let dummy_pubkey = PublicKey::from_slice(&pk).unwrap();
                let remote_last_secret = if self.context.cur_counterparty_commitment_transaction_number + 1 < INITIAL_COMMITMENT_NUMBER {
                        let remote_last_secret = self.context.commitment_secrets.get_secret(self.context.cur_counterparty_commitment_transaction_number + 2).unwrap();
-                       log_trace!(logger, "Enough info to generate a Data Loss Protect with per_commitment_secret {} for channel {}", log_bytes!(remote_last_secret), log_bytes!(self.channel_id()));
+                       log_trace!(logger, "Enough info to generate a Data Loss Protect with per_commitment_secret {} for channel {}", log_bytes!(remote_last_secret), log_bytes!(self.context.channel_id()));
                        remote_last_secret
                } else {
-                       log_info!(logger, "Sending a data_loss_protect with no previous remote per_commitment_secret for channel {}", log_bytes!(self.channel_id()));
+                       log_info!(logger, "Sending a data_loss_protect with no previous remote per_commitment_secret for channel {}", log_bytes!(self.context.channel_id()));
                        [0;32]
                };
                self.mark_awaiting_response();
                msgs::ChannelReestablish {
-                       channel_id: self.channel_id(),
+                       channel_id: self.context.channel_id(),
                        // The protocol has two different commitment number concepts - the "commitment
                        // transaction number", which starts from 0 and counts up, and the "revocation key
                        // index" which starts at INITIAL_COMMITMENT_NUMBER and counts down. We track
@@ -6036,7 +6048,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                        return Err(ChannelError::Ignore("Cannot send 0-msat HTLC".to_owned()));
                }
 
-               let available_balances = self.get_available_balances();
+               let available_balances = self.context.get_available_balances();
                if amount_msat < available_balances.next_outbound_htlc_minimum_msat {
                        return Err(ChannelError::Ignore(format!("Cannot send less than our next-HTLC minimum - {} msat",
                                available_balances.next_outbound_htlc_minimum_msat)));
@@ -6157,8 +6169,8 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
        }
 
        fn build_commitment_no_state_update<L: Deref>(&self, logger: &L) -> (Txid, Vec<(HTLCOutputInCommitment, Option<&HTLCSource>)>) where L::Target: Logger {
-               let counterparty_keys = self.build_remote_transaction_keys();
-               let commitment_stats = self.build_commitment_transaction(self.context.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, true, logger);
+               let counterparty_keys = self.context.build_remote_transaction_keys();
+               let commitment_stats = self.context.build_commitment_transaction(self.context.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, true, logger);
                let counterparty_commitment_txid = commitment_stats.tx.trust().txid();
 
                #[cfg(any(test, fuzzing))]
@@ -6172,7 +6184,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                                                && info.next_holder_htlc_id == self.context.next_holder_htlc_id
                                                && info.next_counterparty_htlc_id == self.context.next_counterparty_htlc_id
                                                && info.feerate == self.context.feerate_per_kw {
-                                                       let actual_fee = Self::commit_tx_fee_msat(self.context.feerate_per_kw, commitment_stats.num_nondust_htlcs, self.context.opt_anchors());
+                                                       let actual_fee = commit_tx_fee_msat(self.context.feerate_per_kw, commitment_stats.num_nondust_htlcs, self.context.opt_anchors());
                                                        assert_eq!(actual_fee, info.fee);
                                                }
                                }
@@ -6189,8 +6201,8 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                #[cfg(any(test, fuzzing))]
                self.build_commitment_no_state_update(logger);
 
-               let counterparty_keys = self.build_remote_transaction_keys();
-               let commitment_stats = self.build_commitment_transaction(self.context.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, true, logger);
+               let counterparty_keys = self.context.build_remote_transaction_keys();
+               let commitment_stats = self.context.build_commitment_transaction(self.context.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, true, logger);
                let counterparty_commitment_txid = commitment_stats.tx.trust().txid();
                let (signature, htlc_signatures);
 
@@ -6207,15 +6219,15 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
 
                        log_trace!(logger, "Signed remote commitment tx {} (txid {}) with redeemscript {} -> {} in channel {}",
                                encode::serialize_hex(&commitment_stats.tx.trust().built_transaction().transaction),
-                               &counterparty_commitment_txid, encode::serialize_hex(&self.get_funding_redeemscript()),
-                               log_bytes!(signature.serialize_compact()[..]), log_bytes!(self.channel_id()));
+                               &counterparty_commitment_txid, encode::serialize_hex(&self.context.get_funding_redeemscript()),
+                               log_bytes!(signature.serialize_compact()[..]), log_bytes!(self.context.channel_id()));
 
                        for (ref htlc_sig, ref htlc) in htlc_signatures.iter().zip(htlcs) {
                                log_trace!(logger, "Signed remote HTLC tx {} with redeemscript {} with pubkey {} -> {} in channel {}",
-                                       encode::serialize_hex(&chan_utils::build_htlc_transaction(&counterparty_commitment_txid, commitment_stats.feerate_per_kw, self.get_holder_selected_contest_delay(), htlc, self.context.opt_anchors(), false, &counterparty_keys.broadcaster_delayed_payment_key, &counterparty_keys.revocation_key)),
+                                       encode::serialize_hex(&chan_utils::build_htlc_transaction(&counterparty_commitment_txid, commitment_stats.feerate_per_kw, self.context.get_holder_selected_contest_delay(), htlc, self.context.opt_anchors(), false, &counterparty_keys.broadcaster_delayed_payment_key, &counterparty_keys.revocation_key)),
                                        encode::serialize_hex(&chan_utils::get_htlc_redeemscript(&htlc, self.context.opt_anchors(), &counterparty_keys)),
                                        log_bytes!(counterparty_keys.broadcaster_htlc_key.serialize()),
-                                       log_bytes!(htlc_sig.serialize_compact()[..]), log_bytes!(self.channel_id()));
+                                       log_bytes!(htlc_sig.serialize_compact()[..]), log_bytes!(self.context.channel_id()));
                        }
                }
 
@@ -6246,11 +6258,6 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                }
        }
 
-       /// Get forwarding information for the counterparty.
-       pub fn counterparty_forwarding_info(&self) -> Option<CounterpartyForwardingInfo> {
-               self.context.counterparty_forwarding_info.clone()
-       }
-
        pub fn channel_update(&mut self, msg: &msgs::ChannelUpdate) -> Result<(), ChannelError> {
                if msg.contents.htlc_minimum_msat >= self.context.channel_value_satoshis * 1000 {
                        return Err(ChannelError::Close("Minimum htlc value is greater than channel value".to_string()));
@@ -6386,7 +6393,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                // We go ahead and "free" any holding cell HTLCs or HTLCs we haven't yet committed to and
                // return them to fail the payment.
                let mut dropped_outbound_htlcs = Vec::with_capacity(self.context.holding_cell_htlc_updates.len());
-               let counterparty_node_id = self.get_counterparty_node_id();
+               let counterparty_node_id = self.context.get_counterparty_node_id();
                for htlc_update in self.context.holding_cell_htlc_updates.drain(..) {
                        match htlc_update {
                                HTLCUpdateAwaitingACK::AddHTLC { source, payment_hash, .. } => {
@@ -6395,7 +6402,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                                _ => {}
                        }
                }
-               let monitor_update = if let Some(funding_txo) = self.get_funding_txo() {
+               let monitor_update = if let Some(funding_txo) = self.context.get_funding_txo() {
                        // If we haven't yet exchanged funding signatures (ie channel_state < FundingSent),
                        // returning a channel monitor update here would imply a channel monitor update before
                        // we even registered the channel monitor to begin with, which is invalid.
@@ -6405,7 +6412,7 @@ impl<Signer: WriteableEcdsaChannelSigner> Channel<Signer> {
                        // See test_duplicate_chan_id and test_pre_lockin_no_chan_closed_update for more.
                        if self.context.channel_state & (ChannelState::FundingSent as u32 | ChannelState::ChannelReady as u32 | ChannelState::ShutdownComplete as u32) != 0 {
                                self.context.latest_monitor_update_id = CLOSED_CHANNEL_UPDATE_ID;
-                               Some((self.get_counterparty_node_id(), funding_txo, ChannelMonitorUpdate {
+                               Some((self.context.get_counterparty_node_id(), funding_txo, ChannelMonitorUpdate {
                                        update_id: self.context.latest_monitor_update_id,
                                        updates: vec![ChannelMonitorUpdateStep::ChannelForceClosed { should_broadcast }],
                                }))
@@ -7273,7 +7280,7 @@ mod tests {
        use crate::ln::channelmanager::{self, HTLCSource, PaymentId};
        #[cfg(anchors)]
        use crate::ln::channel::InitFeatures;
-       use crate::ln::channel::{Channel, InboundHTLCOutput, OutboundHTLCOutput, InboundHTLCState, OutboundHTLCState, HTLCCandidate, HTLCInitiator};
+       use crate::ln::channel::{Channel, InboundHTLCOutput, OutboundHTLCOutput, InboundHTLCState, OutboundHTLCState, HTLCCandidate, HTLCInitiator, commit_tx_fee_msat};
        use crate::ln::channel::{MAX_FUNDING_SATOSHIS_NO_WUMBO, TOTAL_BITCOIN_SUPPLY_SATOSHIS, MIN_THEIR_CHAN_RESERVE_SATOSHIS};
        use crate::ln::features::ChannelTypeFeatures;
        use crate::ln::msgs::{ChannelUpdate, DecodeError, UnsignedChannelUpdate, MAX_VALUE_MSAT};
@@ -7472,16 +7479,16 @@ mod tests {
                // Make sure when Node A calculates their local commitment transaction, none of the HTLCs pass
                // the dust limit check.
                let htlc_candidate = HTLCCandidate::new(htlc_amount_msat, HTLCInitiator::LocalOffered);
-               let local_commit_tx_fee = node_a_chan.next_local_commit_tx_fee_msat(htlc_candidate, None);
-               let local_commit_fee_0_htlcs = Channel::<EnforcingSigner>::commit_tx_fee_msat(node_a_chan.context.feerate_per_kw, 0, node_a_chan.context.opt_anchors());
+               let local_commit_tx_fee = node_a_chan.context.next_local_commit_tx_fee_msat(htlc_candidate, None);
+               let local_commit_fee_0_htlcs = commit_tx_fee_msat(node_a_chan.context.feerate_per_kw, 0, node_a_chan.context.opt_anchors());
                assert_eq!(local_commit_tx_fee, local_commit_fee_0_htlcs);
 
                // Finally, make sure that when Node A calculates the remote's commitment transaction fees, all
                // of the HTLCs are seen to be above the dust limit.
                node_a_chan.context.channel_transaction_parameters.is_outbound_from_holder = false;
-               let remote_commit_fee_3_htlcs = Channel::<EnforcingSigner>::commit_tx_fee_msat(node_a_chan.context.feerate_per_kw, 3, node_a_chan.context.opt_anchors());
+               let remote_commit_fee_3_htlcs = commit_tx_fee_msat(node_a_chan.context.feerate_per_kw, 3, node_a_chan.context.opt_anchors());
                let htlc_candidate = HTLCCandidate::new(htlc_amount_msat, HTLCInitiator::LocalOffered);
-               let remote_commit_tx_fee = node_a_chan.next_remote_commit_tx_fee_msat(htlc_candidate, None);
+               let remote_commit_tx_fee = node_a_chan.context.next_remote_commit_tx_fee_msat(htlc_candidate, None);
                assert_eq!(remote_commit_tx_fee, remote_commit_fee_3_htlcs);
        }
 
@@ -7501,20 +7508,20 @@ mod tests {
                let config = UserConfig::default();
                let mut chan = Channel::<EnforcingSigner>::new_outbound(&fee_est, &&keys_provider, &&keys_provider, node_id, &channelmanager::provided_init_features(&config), 10000000, 100000, 42, &config, 0, 42).unwrap();
 
-               let commitment_tx_fee_0_htlcs = Channel::<EnforcingSigner>::commit_tx_fee_msat(chan.context.feerate_per_kw, 0, chan.context.opt_anchors());
-               let commitment_tx_fee_1_htlc = Channel::<EnforcingSigner>::commit_tx_fee_msat(chan.context.feerate_per_kw, 1, chan.context.opt_anchors());
+               let commitment_tx_fee_0_htlcs = commit_tx_fee_msat(chan.context.feerate_per_kw, 0, chan.context.opt_anchors());
+               let commitment_tx_fee_1_htlc = commit_tx_fee_msat(chan.context.feerate_per_kw, 1, chan.context.opt_anchors());
 
                // If HTLC_SUCCESS_TX_WEIGHT and HTLC_TIMEOUT_TX_WEIGHT were swapped: then this HTLC would be
                // counted as dust when it shouldn't be.
                let htlc_amt_above_timeout = ((253 * htlc_timeout_tx_weight(chan.context.opt_anchors()) / 1000) + chan.context.holder_dust_limit_satoshis + 1) * 1000;
                let htlc_candidate = HTLCCandidate::new(htlc_amt_above_timeout, HTLCInitiator::LocalOffered);
-               let commitment_tx_fee = chan.next_local_commit_tx_fee_msat(htlc_candidate, None);
+               let commitment_tx_fee = chan.context.next_local_commit_tx_fee_msat(htlc_candidate, None);
                assert_eq!(commitment_tx_fee, commitment_tx_fee_1_htlc);
 
                // If swapped: this HTLC would be counted as non-dust when it shouldn't be.
                let dust_htlc_amt_below_success = ((253 * htlc_success_tx_weight(chan.context.opt_anchors()) / 1000) + chan.context.holder_dust_limit_satoshis - 1) * 1000;
                let htlc_candidate = HTLCCandidate::new(dust_htlc_amt_below_success, HTLCInitiator::RemoteOffered);
-               let commitment_tx_fee = chan.next_local_commit_tx_fee_msat(htlc_candidate, None);
+               let commitment_tx_fee = chan.context.next_local_commit_tx_fee_msat(htlc_candidate, None);
                assert_eq!(commitment_tx_fee, commitment_tx_fee_0_htlcs);
 
                chan.context.channel_transaction_parameters.is_outbound_from_holder = false;
@@ -7522,13 +7529,13 @@ mod tests {
                // If swapped: this HTLC would be counted as non-dust when it shouldn't be.
                let dust_htlc_amt_above_timeout = ((253 * htlc_timeout_tx_weight(chan.context.opt_anchors()) / 1000) + chan.context.counterparty_dust_limit_satoshis + 1) * 1000;
                let htlc_candidate = HTLCCandidate::new(dust_htlc_amt_above_timeout, HTLCInitiator::LocalOffered);
-               let commitment_tx_fee = chan.next_remote_commit_tx_fee_msat(htlc_candidate, None);
+               let commitment_tx_fee = chan.context.next_remote_commit_tx_fee_msat(htlc_candidate, None);
                assert_eq!(commitment_tx_fee, commitment_tx_fee_0_htlcs);
 
                // If swapped: this HTLC would be counted as dust when it shouldn't be.
                let htlc_amt_below_success = ((253 * htlc_success_tx_weight(chan.context.opt_anchors()) / 1000) + chan.context.counterparty_dust_limit_satoshis - 1) * 1000;
                let htlc_candidate = HTLCCandidate::new(htlc_amt_below_success, HTLCInitiator::RemoteOffered);
-               let commitment_tx_fee = chan.next_remote_commit_tx_fee_msat(htlc_candidate, None);
+               let commitment_tx_fee = chan.context.next_remote_commit_tx_fee_msat(htlc_candidate, None);
                assert_eq!(commitment_tx_fee, commitment_tx_fee_1_htlc);
        }
 
@@ -7560,7 +7567,7 @@ mod tests {
                node_a_chan.accept_channel(&accept_channel_msg, &config.channel_handshake_limits, &channelmanager::provided_init_features(&config)).unwrap();
 
                // Node A --> Node B: funding created
-               let output_script = node_a_chan.get_funding_redeemscript();
+               let output_script = node_a_chan.context.get_funding_redeemscript();
                let tx = Transaction { version: 1, lock_time: PackedLockTime::ZERO, input: Vec::new(), output: vec![TxOut {
                        value: 10000000, script_pubkey: output_script.clone(),
                }]};
@@ -7734,7 +7741,7 @@ mod tests {
                let mut node_a_chan = Channel::<EnforcingSigner>::new_outbound(&feeest, &&keys_provider, &&keys_provider, node_b_node_id, &channelmanager::provided_init_features(&config), 10000000, 100000, 42, &config, 0, 42).unwrap();
                assert!(node_a_chan.context.counterparty_forwarding_info.is_none());
                assert_eq!(node_a_chan.context.holder_htlc_minimum_msat, 1); // the default
-               assert!(node_a_chan.counterparty_forwarding_info().is_none());
+               assert!(node_a_chan.context.counterparty_forwarding_info().is_none());
 
                // Make sure that receiving a channel update will update the Channel as expected.
                let update = ChannelUpdate {
@@ -7757,7 +7764,7 @@ mod tests {
                // The counterparty can send an update with a higher minimum HTLC, but that shouldn't
                // change our official htlc_minimum_msat.
                assert_eq!(node_a_chan.context.holder_htlc_minimum_msat, 1);
-               match node_a_chan.counterparty_forwarding_info() {
+               match node_a_chan.context.counterparty_forwarding_info() {
                        Some(info) => {
                                assert_eq!(info.cltv_expiry_delta, 100);
                                assert_eq!(info.fee_base_msat, 110);
@@ -7868,7 +7875,7 @@ mod tests {
                                $( { $htlc_idx: expr, $counterparty_htlc_sig_hex: expr, $htlc_sig_hex: expr, $htlc_tx_hex: expr } ), *
                        } ) => { {
                                let (commitment_tx, htlcs): (_, Vec<HTLCOutputInCommitment>) = {
-                                       let mut commitment_stats = chan.build_commitment_transaction(0xffffffffffff - 42, &keys, true, false, &logger);
+                                       let mut commitment_stats = chan.context.build_commitment_transaction(0xffffffffffff - 42, &keys, true, false, &logger);
 
                                        let htlcs = commitment_stats.htlcs_included.drain(..)
                                                .filter_map(|(htlc, _)| if htlc.transaction_output_index.is_some() { Some(htlc) } else { None })
@@ -7877,11 +7884,11 @@ mod tests {
                                };
                                let trusted_tx = commitment_tx.trust();
                                let unsigned_tx = trusted_tx.built_transaction();
-                               let redeemscript = chan.get_funding_redeemscript();
+                               let redeemscript = chan.context.get_funding_redeemscript();
                                let counterparty_signature = Signature::from_der(&hex::decode($counterparty_sig_hex).unwrap()[..]).unwrap();
                                let sighash = unsigned_tx.get_sighash_all(&redeemscript, chan.context.channel_value_satoshis);
                                log_trace!(logger, "unsigned_tx = {}", hex::encode(serialize(&unsigned_tx.transaction)));
-                               assert!(secp_ctx.verify_ecdsa(&sighash, &counterparty_signature, chan.counterparty_funding_pubkey()).is_ok(), "verify counterparty commitment sig");
+                               assert!(secp_ctx.verify_ecdsa(&sighash, &counterparty_signature, chan.context.counterparty_funding_pubkey()).is_ok(), "verify counterparty commitment sig");
 
                                let mut per_htlc: Vec<(HTLCOutputInCommitment, Option<Signature>)> = Vec::new();
                                per_htlc.clear(); // Don't warn about excess mut for no-HTLC calls
@@ -7899,12 +7906,12 @@ mod tests {
                                        counterparty_signature,
                                        counterparty_htlc_sigs,
                                        &chan.context.holder_signer.pubkeys().funding_pubkey,
-                                       chan.counterparty_funding_pubkey()
+                                       chan.context.counterparty_funding_pubkey()
                                );
                                let (holder_sig, htlc_sigs) = signer.sign_holder_commitment_and_htlcs(&holder_commitment_tx, &secp_ctx).unwrap();
                                assert_eq!(Signature::from_der(&hex::decode($sig_hex).unwrap()[..]).unwrap(), holder_sig, "holder_sig");
 
-                               let funding_redeemscript = chan.get_funding_redeemscript();
+                               let funding_redeemscript = chan.context.get_funding_redeemscript();
                                let tx = holder_commitment_tx.add_holder_sig(&funding_redeemscript, holder_sig);
                                assert_eq!(serialize(&tx)[..], hex::decode($tx_hex).unwrap()[..], "tx");
 
@@ -7917,7 +7924,7 @@ mod tests {
 
                                        let ref htlc = htlcs[$htlc_idx];
                                        let htlc_tx = chan_utils::build_htlc_transaction(&unsigned_tx.txid, chan.context.feerate_per_kw,
-                                               chan.get_counterparty_selected_contest_delay().unwrap(),
+                                               chan.context.get_counterparty_selected_contest_delay().unwrap(),
                                                &htlc, $opt_anchors, false, &keys.broadcaster_delayed_payment_key, &keys.revocation_key);
                                        let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, $opt_anchors, &keys);
                                        let htlc_sighashtype = if $opt_anchors { EcdsaSighashType::SinglePlusAnyoneCanPay } else { EcdsaSighashType::All };