X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fln%2Fchannel.rs;h=1e37335a86f6b48a30f8d5582b14d0ab4a6d3d28;hb=e3f0c55182abeab483972175c1dde114741574fd;hp=b1cd603f021d61564af75f2aa8216452973feb0a;hpb=1ee0a66d21cfd3696ed93938ba08281a0c342741;p=rust-lightning diff --git a/lightning/src/ln/channel.rs b/lightning/src/ln/channel.rs index b1cd603f..1e37335a 100644 --- a/lightning/src/ln/channel.rs +++ b/lightning/src/ln/channel.rs @@ -830,1460 +830,1502 @@ impl ChannelContext { 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 { + 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 { - pub context: ChannelContext, -} + /// 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 { + 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 { + 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 { + 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 { + 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 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 { + 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 Channel { - 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 { + 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 { - 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( - fee_estimator: &LowerBoundedFeeEstimator, 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, APIError> - where ES::Target: EntropySource, - SP::Target: SignerProvider, - 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 { + 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 { + 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 { + 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(&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 = 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(fee_estimator: &LowerBoundedFeeEstimator, - feerate_per_kw: u32, cur_feerate_per_kw: Option, 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( - fee_estimator: &LowerBoundedFeeEstimator, 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, ChannelError> - where ES::Target: EntropySource, - SP::Target: SignerProvider, - 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::::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 { + // 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 { + 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) -> 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) -> 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 — 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) { + 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(&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 { + if self.channel_state & (ChannelState::FundingCreated as u32) != 0 { + self.funding_transaction.clone() + } else { + None } + } +} - let mut preimages: Vec = 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 { + pub context: ChannelContext, +} - let total_fee_sat = Channel::::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 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 Channel { + 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 { + 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( + fee_estimator: &LowerBoundedFeeEstimator, 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, APIError> + where ES::Target: EntropySource, + SP::Target: SignerProvider, + 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 - (&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(&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(&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(&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(&mut self, htlc_id_arg: u64, err_packet: msgs::OnionErrorPacket, mut force_holding_cell: bool, logger: &L) - -> Result, 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(fee_estimator: &LowerBoundedFeeEstimator, + feerate_per_kw: u32, cur_feerate_per_kw: Option, 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( + fee_estimator: &LowerBoundedFeeEstimator, 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, ChannelError> + where ES::Target: EntropySource, + SP::Target: SignerProvider, + 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::::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 Channel { } // 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 Channel { 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 Channel { } } 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(&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( - &mut self, msg: &msgs::FundingCreated, best_block: BestBlock, signer_provider: &SP, logger: &L - ) -> Result<(msgs::FundingSigned, ChannelMonitor), ChannelError> - where - SP::Target: SignerProvider, - 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 + (&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(&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(&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(&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( - &mut self, msg: &msgs::FundingSigned, best_block: BestBlock, signer_provider: &SP, logger: &L - ) -> Result, ChannelError> - where - SP::Target: SignerProvider, - 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(&mut self, htlc_id_arg: u64, err_packet: msgs::OnionErrorPacket, mut force_holding_cell: bool, logger: &L) + -> Result, 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( - &mut self, msg: &msgs::ChannelReady, node_signer: &NS, genesis_block_hash: BlockHash, - user_config: &UserConfig, best_block: &BestBlock, logger: &L - ) -> Result, 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 { - 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) -> 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) -> 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(&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 — 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( + &mut self, msg: &msgs::FundingCreated, best_block: BestBlock, signer_provider: &SP, logger: &L + ) -> Result<(msgs::FundingSigned, ChannelMonitor), ChannelError> + where + SP::Target: SignerProvider, + 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) { - (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( + &mut self, msg: &msgs::FundingSigned, best_block: BestBlock, signer_provider: &SP, logger: &L + ) -> Result, ChannelError> + where + SP::Target: SignerProvider, + 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( + &mut self, msg: &msgs::ChannelReady, node_signer: &NS, genesis_block_hash: BlockHash, + user_config: &UserConfig, best_block: &BestBlock, logger: &L + ) -> Result, 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(&mut self, msg: &msgs::UpdateAddHTLC, mut pending_forward_status: PendingHTLCStatus, create_pending_htlc_status: F, logger: &L) -> Result<(), ChannelError> @@ -3127,8 +3384,8 @@ impl Channel { 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 Channel { 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 Channel { 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 Channel { // 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 Channel { // 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 Channel { 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 Channel { 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 Channel { 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 Channel { 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 Channel { 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 Channel { } 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 Channel { 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 Channel { 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 Channel { 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 Channel { 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 Channel { 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 Channel { 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 Channel { } // 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::::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 Channel { // 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 Channel { 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 Channel { 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 Channel { 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 Channel { return Err(ChannelError::Close("Peer sent update_fee when we needed a channel_reestablish".to_owned())); } Channel::::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 Channel { // `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 Channel { 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 Channel { 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 Channel { }, &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 Channel { 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 Channel { 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 Channel { // 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 Channel { 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 Channel { }) } 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 Channel { 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 Channel { 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 Channel { 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 Channel { } } - // 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 { - 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 { - self.context.short_channel_id - } - - /// Allowed in any state (including after shutdown) - pub fn latest_inbound_scid_alias(&self) -> Option { - 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 { - 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 { - 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 { - 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 { - 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 { - 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 { - 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 { - 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 Channel { 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 Channel { }) } - 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 { - // 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 Channel { .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 Channel { 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 Channel { } 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 Channel { } 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 Channel { 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 Channel { /// [`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 Channel { 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 Channel { /// If an Err is returned, it is a ChannelError::Close (for get_outbound_funding_created) fn get_outbound_funding_created_signature(&mut self, logger: &L) -> Result 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 Channel { 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 Channel { 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 Channel { 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 Channel { 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 Channel { 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 Channel { 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 Channel { } fn build_commitment_no_state_update(&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 Channel { && 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 Channel { #[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 Channel { 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 Channel { } } - /// Get forwarding information for the counterparty. - pub fn counterparty_forwarding_info(&self) -> Option { - 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 Channel { // 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 Channel { _ => {} } } - 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 Channel { // 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::::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::::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::::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::::commit_tx_fee_msat(chan.context.feerate_per_kw, 0, chan.context.opt_anchors()); - let commitment_tx_fee_1_htlc = Channel::::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::::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, $htlc_tx_hex: expr } ), * } ) => { { let (commitment_tx, htlcs): (_, Vec) = { - let mut commitment_stats = chan.build_commitment_transaction(0xffffffffffff - 42, &keys, true, false, &logger); + let mut commitment_stats = chan.context.build_commitment_transaction(0xffffffffffff - 42, &keys, true, false, &logger); let htlcs = commitment_stats.htlcs_included.drain(..) .filter_map(|(htlc, _)| if htlc.transaction_output_index.is_some() { Some(htlc) } else { None }) @@ -7877,11 +7884,11 @@ mod tests { }; let trusted_tx = commitment_tx.trust(); let unsigned_tx = trusted_tx.built_transaction(); - let redeemscript = chan.get_funding_redeemscript(); + let redeemscript = chan.context.get_funding_redeemscript(); let counterparty_signature = Signature::from_der(&hex::decode($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)> = 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 };