X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fln%2Fchannel.rs;h=1e37335a86f6b48a30f8d5582b14d0ab4a6d3d28;hb=e3f0c55182abeab483972175c1dde114741574fd;hp=a03a470a5000c142c145c614dace5073e03596a8;hpb=497aeb006f6cc004a66a660222010546af96075a;p=rust-lightning diff --git a/lightning/src/ln/channel.rs b/lightning/src/ln/channel.rs index a03a470a..1e37335a 100644 --- a/lightning/src/ln/channel.rs +++ b/lightning/src/ln/channel.rs @@ -1301,741 +1301,881 @@ impl ChannelContext { preimages } } -} - -// Internal utility functions for channels - -/// 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 -} - -/// 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)) -} - -/// 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)) -} - -// 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 -} - -// 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, -} - -#[cfg(any(test, fuzzing))] -struct CommitmentTxInfoCached { - fee: u64, - total_pending_htlcs: usize, - next_holder_htlc_id: u64, - next_counterparty_htlc_id: u64, - feerate: u32, -} - -pub const DEFAULT_MAX_HTLCS: u16 = 50; -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 } -} - -#[cfg(not(test))] -const COMMITMENT_TX_WEIGHT_PER_HTLC: u64 = 172; -#[cfg(test)] -pub const COMMITMENT_TX_WEIGHT_PER_HTLC: u64 = 172; + #[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(); -pub const ANCHOR_OUTPUT_VALUE_SATOSHI: u64 = 330; + TxCreationKeys::derive_new(&self.secp_ctx, &per_commitment_point, delayed_payment_base, htlc_basepoint, &counterparty_pubkeys.revocation_basepoint, &counterparty_pubkeys.htlc_basepoint) + } -/// 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; + #[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(); -/// 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; + 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) + } -/// Total bitcoin supply in satoshis. -pub const TOTAL_BITCOIN_SUPPLY_SATOSHIS: u64 = 21_000_000 * 1_0000_0000; + /// 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()) + } -/// 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; + fn counterparty_funding_pubkey(&self) -> &PublicKey { + &self.get_counterparty_pubkeys().funding_pubkey + } -/// 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; + pub fn get_feerate_sat_per_1000_weight(&self) -> u32 { + self.feerate_per_kw + } -/// 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; + 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 let Some(feerate) = outbound_feerate_update { + feerate_per_kw = cmp::max(feerate_per_kw, feerate); + } + cmp::max(2530, feerate_per_kw * 1250 / 1000) + } -// Just a reasonable implementation-specific safe lower bound, higher than the dust limit. -pub const MIN_THEIR_CHAN_RESERVE_SATOSHIS: u64 = 1000; + /// Get forwarding information for the counterparty. + pub fn counterparty_forwarding_info(&self) -> Option { + self.counterparty_forwarding_info.clone() + } -/// 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), -} + /// 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, + }; -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), + 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 } -} -macro_rules! secp_check { - ($res: expr, $err: expr) => { - match $res { - Ok(thing) => thing, - Err(_) => return Err(ChannelError::Close($err)), - } - }; -} + /// 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, + }; -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(); + 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; + } } - // 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(); + 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; + } } } - - ret + stats } - /// 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)) - } - - // 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(); + /// 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 !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) }); + 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 channel_type = Self::get_initial_channel_type(&config, their_features); - debug_assert!(channel_type.is_subset(&channelmanager::provided_channel_type_features(&config))); + 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 feerate = fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::Normal); + let mut available_capacity_msat = outbound_capacity_msat; - 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) }); - } + 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; + } - let mut secp_ctx = Secp256k1::new(); - secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes()); + 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(())); - 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()}), + // 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 { None }; - - if let Some(shutdown_scriptpubkey) = &shutdown_scriptpubkey { - if !shutdown_scriptpubkey.is_compatible(&their_features) { - return Err(APIError::IncompatibleShutdownScript { script: shutdown_scriptpubkey.clone() }); + } 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; } - } - 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()}), - }; + 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); - let temporary_channel_id = entropy_source.get_secure_random_bytes(); + 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); - Ok(Channel { - context: ChannelContext { - user_id, + 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); + } + } - 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, - }, + let mut next_outbound_htlc_minimum_msat = context.counterparty_htlc_minimum_msat; - prev_config: 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_handshake_limits_override: Some(config.channel_handshake_limits.clone()), + 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); + } - 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, + 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); + } - latest_monitor_update_id: 0, + 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); + } + } - holder_signer, - shutdown_scriptpubkey, - destination_script, + available_capacity_msat = cmp::min(available_capacity_msat, + context.counterparty_max_htlc_value_in_flight_msat - outbound_stats.pending_htlcs_value_msat); - cur_holder_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER, - cur_counterparty_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER, - value_to_self_msat, + if outbound_stats.pending_htlcs + 1 > context.counterparty_max_accepted_htlcs as u32 { + available_capacity_msat = 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, + 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, + } + } - resend_order: RAACommitmentOrder::CommitmentFirst, + 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) + } - 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(), + /// 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()); - #[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)), + 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; - last_sent_closing_fee: None, - pending_counterparty_closing_signed: None, - closing_fee_limits: None, - target_closing_feerate_sats_per_kw: 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; + } + } + } - inbound_awaiting_accept: false, + 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; + } - 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, + 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. + _ => {}, + } + } - 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 + 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 }, - 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, - - 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(), + _ => {}, // 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. } - }) - } - - 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(()); - } + + 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()); } - return Err(ChannelError::Close(format!("Peer's feerate much too low. Actual: {}. Our expected lower limit: {} (- 250)", feerate_per_kw, lower_limit))); + 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); } - Ok(()) + res } - /// 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 }; - - // 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())); - } + /// 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()); - // 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() + let (htlc_success_dust_limit, htlc_timeout_dust_limit) = if context.opt_anchors() { + (0, 0) } 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(); - - 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 + (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; - 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))); + 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; + } + } } - // 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))); + // 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; } - 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())); - } - 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))); + for ref htlc in 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, + _ => {}, + } } - // 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))); - } - - // 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 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(); + 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 + } - 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))); + /// 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 } + } +} - // 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))); - } +// Internal utility functions for channels - 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())); - } +/// 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 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 }; +/// 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)) +} - 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 }; +/// 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 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))); - } - } +// 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 destination_script = match signer_provider.get_destination_script() { - Ok(script) => script, - Err(_) => return Err(ChannelError::Close("Failed to get destination script".to_owned())), - }; +// 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 +} - let mut secp_ctx = Secp256k1::new(); - secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes()); +// 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 chan = Channel { - context: ChannelContext { - 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, +} - config: LegacyChannelConfig { - options: config.channel_config.clone(), - announced_channel, - commit_upfront_shutdown_pubkey: config.channel_handshake_config.commit_upfront_shutdown_pubkey, - }, +pub const DEFAULT_MAX_HTLCS: u16 = 50; - prev_config: None, +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 } +} - inbound_handshake_limits_override: None, +#[cfg(not(test))] +const COMMITMENT_TX_WEIGHT_PER_HTLC: u64 = 172; +#[cfg(test)] +pub const COMMITMENT_TX_WEIGHT_PER_HTLC: u64 = 172; - 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, +pub const ANCHOR_OUTPUT_VALUE_SATOSHI: u64 = 330; - latest_monitor_update_id: 0, +/// 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; - holder_signer, - shutdown_scriptpubkey, - destination_script, +/// 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; - cur_holder_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER, - cur_counterparty_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER, - value_to_self_msat: msg.push_msat, +/// Total bitcoin supply in satoshis. +pub const TOTAL_BITCOIN_SUPPLY_SATOSHIS: u64 = 21_000_000 * 1_0000_0000; - 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, +/// 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; - resend_order: RAACommitmentOrder::CommitmentFirst, +/// 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; - 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(), +/// 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; - #[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)), +// Just a reasonable implementation-specific safe lower bound, higher than the dust limit. +pub const MIN_THEIR_CHAN_RESERVE_SATOSHIS: u64 = 1000; - last_sent_closing_fee: None, - pending_counterparty_closing_signed: None, - closing_fee_limits: None, +/// 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), + } + } +} + +macro_rules! secp_check { + ($res: expr, $err: expr) => { + match $res { + Ok(thing) => thing, + Err(_) => return Err(ChannelError::Close($err)), + } + }; +} + +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(); + } + + // 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(); + } + } + + ret + } + + /// 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)) + } + + // 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(); + + 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) }); + } + + let channel_type = Self::get_initial_channel_type(&config, their_features); + debug_assert!(channel_type.is_subset(&channelmanager::provided_channel_type_features(&config))); + + let feerate = fee_estimator.bounded_sat_per_1000_weight(ConfirmationTarget::Normal); + + 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) }); + } + + let mut secp_ctx = Secp256k1::new(); + secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes()); + + 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 }; + + if let Some(shutdown_scriptpubkey) = &shutdown_scriptpubkey { + if !shutdown_scriptpubkey.is_compatible(&their_features) { + return Err(APIError::IncompatibleShutdownScript { script: shutdown_scriptpubkey.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()}), + }; + + let temporary_channel_id = entropy_source.get_secure_random_bytes(); + + Ok(Channel { + context: ChannelContext { + user_id, + + 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, + }, + + prev_config: None, + + 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: true, + 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: msg.feerate_per_kw, - channel_value_satoshis: msg.funding_satoshis, - counterparty_dust_limit_satoshis: msg.dust_limit_satoshis, + 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: 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), + 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: msg.htlc_minimum_msat, + 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: msg.max_accepted_htlcs, + counterparty_max_accepted_htlcs: 0, 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)), + 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: false, - counterparty_parameters: Some(CounterpartyChannelTransactionParameters { - selected_contest_delay: msg.to_self_delay, - pubkeys: counterparty_pubkeys, - }), + is_outbound_from_holder: true, + counterparty_parameters: None, funding_outpoint: None, - opt_anchors: if opt_anchors { Some(()) } else { 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: Some(msg.first_per_commitment_point), + counterparty_cur_commitment_point: None, counterparty_prev_commitment_point: None, counterparty_node_id, - counterparty_shutdown_scriptpubkey, + counterparty_shutdown_scriptpubkey: None, commitment_secrets: CounterpartyCommitmentSecrets::new(), @@ -2066,1264 +2206,1157 @@ impl Channel { pending_monitor_updates: Vec::new(), } - }; - - Ok(chan) - } - - #[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() + }) } - #[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 + 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))); } - if let Some(spk) = b_scriptpubkey { - ret += ((8+1) + // output values and script length - spk.len() as u64) * 4; // scriptpubkey and witness multiplier + 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))); } - ret + Ok(()) } - #[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()); + /// 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 }; - 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 }; + // 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())); + } - 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; - } + // 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(); - if skip_remote_output || value_to_counterparty as u64 <= self.context.holder_dust_limit_satoshis { - value_to_counterparty = 0; - } + 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 value_to_holder as u64 <= self.context.holder_dust_limit_satoshis { - value_to_holder = 0; + 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))); } - 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(); - - 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 funding_outpoint(&self) -> OutPoint { - self.context.channel_transaction_parameters.funding_outpoint.unwrap() - } - - #[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.context.get_holder_pubkeys().delayed_payment_basepoint; - let htlc_basepoint = &self.context.get_holder_pubkeys().htlc_basepoint; - let counterparty_pubkeys = self.context.get_counterparty_pubkeys(); + // 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)?; - TxCreationKeys::derive_new(&self.context.secp_ctx, &per_commitment_point, delayed_payment_base, htlc_basepoint, &counterparty_pubkeys.revocation_basepoint, &counterparty_pubkeys.htlc_basepoint) - } + 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())); + } + 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))); + } - #[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.context.get_holder_pubkeys().revocation_basepoint; - let htlc_basepoint = &self.context.get_holder_pubkeys().htlc_basepoint; - let counterparty_pubkeys = self.context.get_counterparty_pubkeys(); + // 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))); + } - 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) - } + // Convert things into internal flags and prep our state: - /// 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.context.get_holder_pubkeys().funding_pubkey, self.counterparty_funding_pubkey()) - } + 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())); + } + } - /// 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 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))); } - } - 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"); + // 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))); } - 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 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())); + } - // 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 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"); + 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))) } - 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 + 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())); } - 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 {}; - } - - // 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(), - }], - }; + } else { None }; - 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 }; - } - }, - _ => {} - } + 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())), } - 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); + } else { None }; - { - 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 }; + 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))); } - 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())); } - 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 destination_script = match signer_provider.get_destination_script() { + Ok(script) => script, + Err(_) => return Err(ChannelError::Close("Failed to get destination script".to_owned())), + }; - 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 {}, - } - } + let mut secp_ctx = Secp256k1::new(); + secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes()); - /// 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?")) - } + let chan = Channel { + context: ChannelContext { + user_id, - /// 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); + config: LegacyChannelConfig { + options: config.channel_config.clone(), + announced_channel, + commit_upfront_shutdown_pubkey: config.channel_handshake_config.commit_upfront_shutdown_pubkey, + }, - // 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. + prev_config: None, - 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); - } + inbound_handshake_limits_override: 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; - } + 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, - // 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); - } - - 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())); - } + latest_monitor_update_id: 0, - Ok(Some(msgs::UpdateFailHTLC { - channel_id: self.context.channel_id(), - htlc_id: htlc_id_arg, - reason: err_packet - })) - } + holder_signer, + shutdown_scriptpubkey, + destination_script, - // Message handlers: + cur_holder_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER, + cur_counterparty_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER, + value_to_self_msat: msg.push_msat, - 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 }; + 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, - // 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 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))); - } + resend_order: RAACommitmentOrder::CommitmentFirst, - // 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))); - } + 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 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; - } + #[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 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 }; + last_sent_closing_fee: None, + pending_counterparty_closing_signed: None, + closing_fee_limits: None, + target_closing_feerate_sats_per_kw: 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; + inbound_awaiting_accept: true, - 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)); - } + funding_tx_confirmed_in: None, + funding_tx_confirmation_height: 0, + short_channel_id: None, + channel_creation_height: current_chain_height, - 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 - }; + 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)), - self.context.channel_transaction_parameters.counterparty_parameters = Some(CounterpartyChannelTransactionParameters { - selected_contest_delay: msg.to_self_delay, - pubkeys: counterparty_pubkeys, - }); + counterparty_forwarding_info: None, - self.context.counterparty_cur_commitment_point = Some(msg.first_per_commitment_point); - self.context.counterparty_shutdown_scriptpubkey = counterparty_shutdown_scriptpubkey; + 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, - 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. + counterparty_cur_commitment_point: Some(msg.first_per_commitment_point), + counterparty_prev_commitment_point: None, + counterparty_node_id, - Ok(()) - } + counterparty_shutdown_scriptpubkey, - 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(); + commitment_secrets: CounterpartyCommitmentSecrets::new(), - let keys = self.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.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.counterparty_funding_pubkey()), "Invalid funding_created signature from peer".to_owned()); - } + channel_update_status: ChannelUpdateStatus::Enabled, + closing_signed_in_flight: false, - let counterparty_keys = self.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; + announcement_sigs: 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.context.channel_id()), counterparty_initial_bitcoin_tx.txid, encode::serialize_hex(&counterparty_initial_bitcoin_tx.transaction)); + #[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 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; + workaround_lnd_bug_4006: None, + sent_message_awaiting_response: None, - // 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)) - } + latest_inbound_scid_alias: None, + outbound_scid_alias, - fn counterparty_funding_pubkey(&self) -> &PublicKey { - &self.context.get_counterparty_pubkeys().funding_pubkey - } + channel_pending_event_emitted: false, + channel_ready_event_emitted: false, - 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"); - } + #[cfg(any(test, fuzzing))] + historical_inbound_htlc_fulfills: HashSet::new(), - 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); + channel_type, + channel_keys_id, - 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); + pending_monitor_updates: Vec::new(), } }; - let holder_commitment_tx = HolderCommitmentTransaction::new( - initial_commitment_tx, - msg.signature, - Vec::new(), - &self.context.get_holder_pubkeys().funding_pubkey, - self.counterparty_funding_pubkey() - ); + Ok(chan) + } - self.context.holder_signer.validate_holder_commitment(&holder_commitment_tx, Vec::new()) - .map_err(|_| ChannelError::Close("Failed to validate our commitment".to_owned()))?; + #[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() + } - // Now that we're past error-generating stuff, update our local state: + #[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 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.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); + #[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()); - 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); + 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 }; - 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; + 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; + } - log_info!(logger, "Generated funding_signed for peer for channel {}", log_bytes!(self.context.channel_id())); + if skip_remote_output || value_to_counterparty as u64 <= self.context.holder_dust_limit_satoshis { + value_to_counterparty = 0; + } - 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()); + if value_to_holder as u64 <= self.context.holder_dust_limit_satoshis { + value_to_holder = 0; + } - Ok((msgs::FundingSigned { - channel_id: self.context.channel_id, - signature, - #[cfg(taproot)] - partial_signature_with_nonce: None, - }, channel_monitor)) + 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(); + + 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) } - /// 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"); + fn funding_outpoint(&self) -> OutPoint { + self.context.channel_transaction_parameters.funding_outpoint.unwrap() + } + + /// 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_script = self.get_funding_redeemscript(); + 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 counterparty_keys = self.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 payment_hash_calc = PaymentHash(Sha256::hash(&payment_preimage_arg.0[..]).into_inner()); - 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)); + // 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.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())); + 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 holder_commitment_tx = HolderCommitmentTransaction::new( - initial_commitment_tx, - msg.signature, - Vec::new(), - &self.context.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()))?; - + // 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 funding_redeemscript = self.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); + 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); - 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 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())); + } - 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; + 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, + }), + } + } - log_info!(logger, "Received funding_signed from peer for channel {}", log_bytes!(self.context.channel_id())); + 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 {}, + } + } - 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) + /// 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 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())); + /// 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); - 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); + // 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 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 non_shutdown_state = self.context.channel_state & (!MULTI_STATE_FLAGS); + 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; + } - 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 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); - } else { - return Err(ChannelError::Close("Peer sent a channel_ready at a strange time".to_owned())); } - 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())); + 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())); + } - Ok(self.get_announcement_sigs(node_signer, genesis_block_hash, user_config, best_block.height(), logger)) + Ok(Some(msgs::UpdateFailHTLC { + channel_id: self.context.channel_id(), + htlc_id: htlc_id_arg, + reason: err_packet + })) } - /// 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() - } else { - None - } - } + // Message handlers: - /// 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, - }; + 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 (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; - } + // 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 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))); } - stats - } - /// 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, - }; + // 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))); + } - 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 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())); } - if htlc.amount_msat / 1000 < holder_dust_limit_timeout_sat { - stats.on_holder_tx_dust_exposure_msat += htlc.amount_msat; + } 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; } - 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; + 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())); } } - } - stats - } + } 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 { - // 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); + 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 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; - } + 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)); } - 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_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 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; - } + self.context.channel_transaction_parameters.counterparty_parameters = Some(CounterpartyChannelTransactionParameters { + selected_contest_delay: msg.to_self_delay, + pubkeys: counterparty_pubkeys, + }); - 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(())); + self.context.counterparty_cur_commitment_point = Some(msg.first_per_commitment_point); + self.context.counterparty_shutdown_scriptpubkey = counterparty_shutdown_scriptpubkey; - // 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; - } + 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. - 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); + Ok(()) + } - 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); + 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(); - 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 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()); } - let mut next_outbound_htlc_minimum_msat = self.context.counterparty_htlc_minimum_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 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 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_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.context.get_max_dust_htlc_exposure_msat() as i64 { - remaining_msat_below_dust_exposure_limit = - Some(self.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); - } + 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; - 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.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()), - self.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); + // 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)) + } + + 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"); } - 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_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); } - } + }; - available_capacity_msat = cmp::min(available_capacity_msat, - self.context.counterparty_max_htlc_value_in_flight_msat - outbound_stats.pending_htlcs_value_msat); + 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() + ); - if outbound_stats.pending_htlcs + 1 > self.context.counterparty_max_accepted_htlcs as u32 { - available_capacity_msat = 0; - } + self.context.holder_signer.validate_holder_commitment(&holder_commitment_tx, Vec::new()) + .map_err(|_| ChannelError::Close("Failed to validate our commitment".to_owned()))?; - 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, - } - } + // Now that we're past error-generating stuff, update our local state: - 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 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); - // 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 - } + 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); - /// 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()); + 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_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; + log_info!(logger, "Generated funding_signed for peer for channel {}", log_bytes!(self.context.channel_id())); - 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; - } - } + 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((msgs::FundingSigned { + channel_id: self.context.channel_id, + signature, + #[cfg(taproot)] + partial_signature_with_nonce: None, + }, channel_monitor)) + } + + /// 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())); } - - 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 - } - // 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; + 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())); } - - 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. - _ => {}, - } + 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"); } - 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. - } - } + let funding_script = self.context.get_funding_redeemscript(); - 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 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(); + + 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 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 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 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())); } - 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 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() { - (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; + self.context.holder_signer.validate_holder_commitment(&holder_commitment_tx, Vec::new()) + .map_err(|_| ChannelError::Close("Failed to validate our commitment".to_owned()))?; - 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; - } - } - } - // 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; + 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); + + 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); + + 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; + + 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> @@ -3351,8 +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))); } @@ -3383,7 +3416,7 @@ 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) }; @@ -3419,7 +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())); @@ -3439,7 +3472,7 @@ 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. @@ -3449,7 +3482,7 @@ impl Channel { } 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())); } @@ -3558,9 +3591,9 @@ 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.context.build_commitment_transaction(self.context.cur_holder_commitment_transaction_number, &keys, true, false, logger); let commitment_txid = { @@ -3570,9 +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!(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.counterparty_funding_pubkey()) { + 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 @@ -3664,7 +3697,7 @@ impl Channel { msg.signature, msg.htlc_signatures.clone(), &self.context.get_holder_pubkeys().funding_pubkey, - self.counterparty_funding_pubkey() + self.context.counterparty_funding_pubkey() ); self.context.holder_signer.validate_holder_commitment(&holder_commitment_tx, commitment_stats.preimages) @@ -4150,9 +4183,9 @@ 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 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; @@ -4394,7 +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; @@ -4402,8 +4435,8 @@ 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.context.get_max_dust_htlc_exposure_msat() { @@ -4920,7 +4953,7 @@ impl Channel { tx.input[0].witness.push(Vec::new()); // First is the multisig dummy let funding_key = self.context.get_holder_pubkeys().funding_pubkey.serialize(); - let counterparty_funding_key = self.counterparty_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(); @@ -4933,7 +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 } @@ -4964,7 +4997,7 @@ 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))); @@ -4978,7 +5011,7 @@ impl Channel { // 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()); }, }; @@ -5126,28 +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 } @@ -5405,7 +5416,7 @@ impl Channel { 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 @@ -5706,7 +5717,7 @@ 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_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) @@ -5794,8 +5805,8 @@ impl Channel { 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.context.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.context.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(), }; @@ -5901,10 +5912,10 @@ impl Channel { "Bad announcement_signatures. Failed to verify node_signature. UnsignedChannelAnnouncement used for verification is {:?}. their_node_key is {:?}", &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)); @@ -6037,7 +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))); @@ -6158,7 +6169,7 @@ 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 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(); @@ -6173,7 +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); } } @@ -6190,7 +6201,7 @@ impl Channel { #[cfg(any(test, fuzzing))] self.build_commitment_no_state_update(logger); - let counterparty_keys = self.build_remote_transaction_keys(); + 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); @@ -6208,7 +6219,7 @@ 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()), + &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) { @@ -6247,11 +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())); @@ -7274,7 +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}; @@ -7473,16 +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); } @@ -7502,20 +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; @@ -7523,13 +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); } @@ -7561,7 +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(), }]}; @@ -7735,7 +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 { @@ -7758,7 +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); @@ -7878,11 +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($counterparty_sig_hex).unwrap()[..]).unwrap(); let sighash = unsigned_tx.get_sighash_all(&redeemscript, chan.context.channel_value_satoshis); log_trace!(logger, "unsigned_tx = {}", hex::encode(serialize(&unsigned_tx.transaction))); - assert!(secp_ctx.verify_ecdsa(&sighash, &counterparty_signature, chan.counterparty_funding_pubkey()).is_ok(), "verify counterparty commitment sig"); + assert!(secp_ctx.verify_ecdsa(&sighash, &counterparty_signature, chan.context.counterparty_funding_pubkey()).is_ok(), "verify counterparty commitment sig"); let mut per_htlc: Vec<(HTLCOutputInCommitment, Option)> = Vec::new(); per_htlc.clear(); // Don't warn about excess mut for no-HTLC calls @@ -7900,12 +7906,12 @@ mod tests { counterparty_signature, counterparty_htlc_sigs, &chan.context.holder_signer.pubkeys().funding_pubkey, - chan.counterparty_funding_pubkey() + chan.context.counterparty_funding_pubkey() ); let (holder_sig, htlc_sigs) = signer.sign_holder_commitment_and_htlcs(&holder_commitment_tx, &secp_ctx).unwrap(); assert_eq!(Signature::from_der(&hex::decode($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");