X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fln%2Fchannel.rs;h=d76840236a1b04945de7703eae62906a6ddd4469;hb=1a743672b92a65e3d401a11001354f3b514bf956;hp=d0e6931f3e20a49242f3daa9b6873f95f7125c81;hpb=31975c5994c8daca5b69c7c3b7d5466409ae8c2d;p=rust-lightning diff --git a/lightning/src/ln/channel.rs b/lightning/src/ln/channel.rs index d0e6931f..d7684023 100644 --- a/lightning/src/ln/channel.rs +++ b/lightning/src/ln/channel.rs @@ -294,6 +294,18 @@ struct HTLCStats { on_counterparty_tx_dust_exposure_msat: u64, on_holder_tx_dust_exposure_msat: u64, holding_cell_msat: u64, + on_holder_tx_holding_cell_htlcs_count: u32, // dust HTLCs *non*-included +} + +/// An enum gathering stats on commitment transaction, either local or remote. +struct CommitmentStats<'a> { + tx: CommitmentTransaction, // the transaction info + feerate_per_kw: u32, // the feerate included to build the transaction + total_fee_sat: u64, // the total fee included in the transaction + num_nondust_htlcs: usize, // the number of HTLC outputs (dust HTLCs *non*-included) + htlcs_included: Vec<(HTLCOutputInCommitment, Option<&'a HTLCSource>)>, // the list of HTLCs (dust HTLCs *included*) which were not ignored when building the transaction + local_balance_msat: u64, // local balance before fees but considering dust limits + remote_balance_msat: u64, // remote balance before fees but considering dust limits } /// Used when calculating whether we or the remote can afford an additional HTLC. @@ -394,7 +406,12 @@ pub(crate) const FUNDING_CONF_DEADLINE_BLOCKS: u32 = 2016; /// size 2. However, if the number of concurrent update_add_htlc is higher, this still /// leads to a channel force-close. Ultimately, this is an issue coming from the /// design of LN state machines, allowing asynchronous updates. -const CONCURRENT_INBOUND_HTLC_FEE_BUFFER: u32 = 2; +pub(crate) const CONCURRENT_INBOUND_HTLC_FEE_BUFFER: u32 = 2; + +/// When a channel is opened, we check that the funding amount is enough to pay for relevant +/// commitment transaction fees, with at least this many HTLCs present on the commitment +/// transaction (not counting the value of the HTLCs themselves). +pub(crate) const MIN_AFFORDABLE_HTLC_COUNT: usize = 4; // 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 @@ -667,6 +684,10 @@ impl Channel { cmp::min(channel_value_satoshis, cmp::max(q, 1000)) //TODO } + pub(crate) fn opt_anchors(&self) -> bool { + self.channel_transaction_parameters.opt_anchors.is_some() + } + // Constructors: pub fn new_outbound( fee_estimator: &F, keys_provider: &K, counterparty_node_id: PublicKey, their_features: &InitFeatures, @@ -696,6 +717,12 @@ impl Channel { let feerate = fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Normal); + 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); + 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(&keys_provider.get_secure_random_bytes()); @@ -726,7 +753,7 @@ impl Channel { cur_holder_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER, cur_counterparty_commitment_transaction_number: INITIAL_COMMITMENT_NUMBER, - value_to_self_msat: channel_value_satoshis * 1000 - push_msat, + value_to_self_msat, pending_inbound_htlcs: Vec::new(), pending_outbound_htlcs: Vec::new(), @@ -778,7 +805,8 @@ impl Channel { holder_selected_contest_delay: config.own_channel_config.our_to_self_delay, is_outbound_from_holder: true, counterparty_parameters: None, - funding_outpoint: None + funding_outpoint: None, + opt_anchors: None, }, funding_transaction: None, @@ -940,8 +968,6 @@ impl Channel { // we either accept their preference or the preferences match local_config.announced_channel = announce; - let background_feerate = fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Background); - let holder_selected_channel_reserve_satoshis = Channel::::get_holder_selected_channel_reserve_satoshis(msg.funding_satoshis); if holder_selected_channel_reserve_satoshis < MIN_CHAN_DUST_LIMIT_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))); @@ -954,17 +980,18 @@ impl Channel { } // check if the funder's amount for the initial commitment tx is sufficient - // for full fee payment + // 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 lower_limit = background_feerate as u64 * COMMITMENT_TX_BASE_WEIGHT; - if funders_amount_msat < lower_limit { - return Err(ChannelError::Close(format!("Insufficient funding amount ({}) for initial commitment. Must be at least {}", funders_amount_msat, lower_limit))); + let commitment_tx_fee = Self::commit_tx_fee_msat(msg.feerate_per_kw, MIN_AFFORDABLE_HTLC_COUNT) / 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))); } - let to_local_msat = msg.push_msat; - let to_remote_msat = funders_amount_msat - background_feerate as u64 * COMMITMENT_TX_BASE_WEIGHT; - if to_local_msat <= msg.channel_reserve_satoshis * 1000 && to_remote_msat <= holder_selected_channel_reserve_satoshis * 1000 { - return Err(ChannelError::Close("Insufficient funding amount for initial commitment".to_owned())); + let to_remote_satoshis = funders_amount_msat / 1000 - commitment_tx_fee; + // While it's reasonable for us to not meet the channel reserve initially (if they don't + // want to push much to us), our counterparty should always have more than our reserve. + if to_remote_satoshis < holder_selected_channel_reserve_satoshis { + return Err(ChannelError::Close("Insufficient funding amount for initial reserve".to_owned())); } let counterparty_shutdown_scriptpubkey = if their_features.supports_upfront_shutdown_script() { @@ -1072,7 +1099,8 @@ impl Channel { selected_contest_delay: msg.to_self_delay, pubkeys: counterparty_pubkeys, }), - funding_outpoint: None + funding_outpoint: None, + opt_anchors: None }, funding_transaction: None, @@ -1118,14 +1146,10 @@ impl Channel { /// have not yet committed it. Such HTLCs will only be included in transactions which are being /// generated by the peer which proposed adding the HTLCs, and thus we need to understand both /// which peer generated this transaction and "to whom" this transaction flows. - /// Returns (the transaction info, the number of HTLC outputs which were present in the - /// transaction, the list of HTLCs which were not ignored when building the transaction). - /// Note that below-dust HTLCs are included in the fourth return value, but not the third, and - /// sources are provided only for outbound HTLCs in the fourth return value. - /// Note that fifth and sixth return values are respectively anticipated holder and counterparty - /// balance, not the value actually paid on-chain, which may be zero if it got rounded to dust. #[inline] - fn build_commitment_transaction(&self, commitment_number: u64, keys: &TxCreationKeys, local: bool, generated_by_local: bool, logger: &L) -> (CommitmentTransaction, u32, usize, Vec<(HTLCOutputInCommitment, Option<&HTLCSource>)>, u64, u64) where L::Target: Logger { + fn build_commitment_transaction(&self, commitment_number: u64, keys: &TxCreationKeys, local: bool, generated_by_local: bool, logger: &L) -> CommitmentStats + where L::Target: Logger + { let mut included_dust_htlcs: Vec<(HTLCOutputInCommitment, Option<&HTLCSource>)> = Vec::new(); let num_htlcs = self.pending_inbound_htlcs.len() + self.pending_outbound_htlcs.len(); let mut included_non_dust_htlcs: Vec<(HTLCOutputInCommitment, Option<&HTLCSource>)> = Vec::with_capacity(num_htlcs); @@ -1244,13 +1268,13 @@ impl Channel { } } - let value_to_self_msat: i64 = (self.value_to_self_msat - local_htlc_total_msat) as i64 + value_to_self_msat_offset; + let mut value_to_self_msat: i64 = (self.value_to_self_msat - local_htlc_total_msat) as i64 + value_to_self_msat_offset; assert!(value_to_self_msat >= 0); // Note that in case they have several just-awaiting-last-RAA fulfills in-progress (ie // AwaitingRemoteRevokeToRemove or AwaitingRemovedRemoteRevoke) we may have allowed them to // "violate" their reserve value by couting those against it. Thus, we have to convert // everything to i64 before subtracting as otherwise we can overflow. - let value_to_remote_msat: i64 = (self.channel_value_satoshis * 1000) as i64 - (self.value_to_self_msat as i64) - (remote_htlc_total_msat as i64) - value_to_self_msat_offset; + let mut value_to_remote_msat: i64 = (self.channel_value_satoshis * 1000) as i64 - (self.value_to_self_msat as i64) - (remote_htlc_total_msat as i64) - value_to_self_msat_offset; assert!(value_to_remote_msat >= 0); #[cfg(debug_assertions)] @@ -1303,7 +1327,7 @@ impl Channel { let tx = CommitmentTransaction::new_with_auxiliary_htlc_data(commitment_number, value_to_a as u64, value_to_b as u64, - false, + self.channel_transaction_parameters.opt_anchors.is_some(), funding_pubkey_a, funding_pubkey_b, keys.clone(), @@ -1316,7 +1340,19 @@ impl Channel { htlcs_included.sort_unstable_by_key(|h| h.0.transaction_output_index.unwrap()); htlcs_included.append(&mut included_dust_htlcs); - (tx, feerate_per_kw, num_nondust_htlcs, htlcs_included, value_to_self_msat as u64, value_to_remote_msat as u64) + // For the stats, trimmed-to-0 the value in msats accordingly + value_to_self_msat = if (value_to_self_msat * 1000) < broadcaster_dust_limit_satoshis as i64 { 0 } else { value_to_self_msat }; + value_to_remote_msat = if (value_to_remote_msat * 1000) < broadcaster_dust_limit_satoshis as i64 { 0 } else { value_to_remote_msat }; + + CommitmentStats { + tx, + feerate_per_kw, + total_fee_sat, + num_nondust_htlcs, + htlcs_included, + local_balance_msat: value_to_self_msat as u64, + remote_balance_msat: value_to_remote_msat as u64, + } } #[inline] @@ -1770,7 +1806,7 @@ impl Channel { let funding_script = self.get_funding_redeemscript(); let keys = self.build_holder_transaction_keys(self.cur_holder_commitment_transaction_number)?; - let initial_commitment_tx = self.build_commitment_transaction(self.cur_holder_commitment_transaction_number, &keys, true, false, logger).0; + let initial_commitment_tx = self.build_commitment_transaction(self.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(); @@ -1784,7 +1820,7 @@ impl Channel { } let counterparty_keys = self.build_remote_transaction_keys()?; - let counterparty_initial_commitment_tx = self.build_commitment_transaction(self.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, false, logger).0; + let counterparty_initial_commitment_tx = self.build_commitment_transaction(self.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(); @@ -1895,7 +1931,7 @@ impl Channel { let funding_script = self.get_funding_redeemscript(); let counterparty_keys = self.build_remote_transaction_keys()?; - let counterparty_initial_commitment_tx = self.build_commitment_transaction(self.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, false, logger).0; + let counterparty_initial_commitment_tx = self.build_commitment_transaction(self.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(); @@ -1903,7 +1939,7 @@ impl Channel { log_bytes!(self.channel_id()), counterparty_initial_bitcoin_tx.txid, encode::serialize_hex(&counterparty_initial_bitcoin_tx.transaction)); let holder_signer = self.build_holder_transaction_keys(self.cur_holder_commitment_transaction_number)?; - let initial_commitment_tx = self.build_commitment_transaction(self.cur_holder_commitment_transaction_number, &holder_signer, true, false, logger).0; + let initial_commitment_tx = self.build_commitment_transaction(self.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(); @@ -1998,17 +2034,18 @@ impl Channel { } /// Returns a HTLCStats about inbound pending htlcs - fn get_inbound_pending_htlc_stats(&self) -> HTLCStats { + fn get_inbound_pending_htlc_stats(&self, outbound_feerate_update: Option) -> HTLCStats { let mut stats = HTLCStats { pending_htlcs: self.pending_inbound_htlcs.len() as u32, pending_htlcs_value_msat: 0, on_counterparty_tx_dust_exposure_msat: 0, on_holder_tx_dust_exposure_msat: 0, holding_cell_msat: 0, + on_holder_tx_holding_cell_htlcs_count: 0, }; - let counterparty_dust_limit_timeout_sat = (self.get_dust_buffer_feerate() as u64 * HTLC_TIMEOUT_TX_WEIGHT / 1000) + self.counterparty_dust_limit_satoshis; - let holder_dust_limit_success_sat = (self.get_dust_buffer_feerate() as u64 * HTLC_SUCCESS_TX_WEIGHT / 1000) + self.holder_dust_limit_satoshis; + let counterparty_dust_limit_timeout_sat = (self.get_dust_buffer_feerate(outbound_feerate_update) as u64 * HTLC_TIMEOUT_TX_WEIGHT / 1000) + self.counterparty_dust_limit_satoshis; + let holder_dust_limit_success_sat = (self.get_dust_buffer_feerate(outbound_feerate_update) as u64 * HTLC_SUCCESS_TX_WEIGHT / 1000) + self.holder_dust_limit_satoshis; for ref htlc in self.pending_inbound_htlcs.iter() { stats.pending_htlcs_value_msat += htlc.amount_msat; if htlc.amount_msat / 1000 < counterparty_dust_limit_timeout_sat { @@ -2022,17 +2059,18 @@ impl Channel { } /// Returns a HTLCStats about pending outbound htlcs, *including* pending adds in our holding cell. - fn get_outbound_pending_htlc_stats(&self) -> HTLCStats { + fn get_outbound_pending_htlc_stats(&self, outbound_feerate_update: Option) -> HTLCStats { let mut stats = HTLCStats { pending_htlcs: self.pending_outbound_htlcs.len() as u32, pending_htlcs_value_msat: 0, on_counterparty_tx_dust_exposure_msat: 0, on_holder_tx_dust_exposure_msat: 0, holding_cell_msat: 0, + on_holder_tx_holding_cell_htlcs_count: 0, }; - let counterparty_dust_limit_success_sat = (self.get_dust_buffer_feerate() as u64 * HTLC_SUCCESS_TX_WEIGHT / 1000) + self.counterparty_dust_limit_satoshis; - let holder_dust_limit_timeout_sat = (self.get_dust_buffer_feerate() as u64 * HTLC_TIMEOUT_TX_WEIGHT / 1000) + self.holder_dust_limit_satoshis; + let counterparty_dust_limit_success_sat = (self.get_dust_buffer_feerate(outbound_feerate_update) as u64 * HTLC_SUCCESS_TX_WEIGHT / 1000) + self.counterparty_dust_limit_satoshis; + let holder_dust_limit_timeout_sat = (self.get_dust_buffer_feerate(outbound_feerate_update) as u64 * HTLC_TIMEOUT_TX_WEIGHT / 1000) + self.holder_dust_limit_satoshis; for ref htlc in self.pending_outbound_htlcs.iter() { stats.pending_htlcs_value_msat += htlc.amount_msat; if htlc.amount_msat / 1000 < counterparty_dust_limit_success_sat { @@ -2053,6 +2091,8 @@ impl Channel { } 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; } } } @@ -2068,11 +2108,11 @@ impl Channel { ( cmp::max(self.channel_value_satoshis as i64 * 1000 - self.value_to_self_msat as i64 - - self.get_inbound_pending_htlc_stats().pending_htlcs_value_msat as i64 + - self.get_inbound_pending_htlc_stats(None).pending_htlcs_value_msat as i64 - Self::get_holder_selected_channel_reserve_satoshis(self.channel_value_satoshis) as i64 * 1000, 0) as u64, cmp::max(self.value_to_self_msat as i64 - - self.get_outbound_pending_htlc_stats().pending_htlcs_value_msat as i64 + - self.get_outbound_pending_htlc_stats(None).pending_htlcs_value_msat as i64 - self.counterparty_selected_channel_reserve_satoshis.unwrap_or(0) as i64 * 1000, 0) as u64 ) @@ -2085,10 +2125,10 @@ impl Channel { // 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(&self, num_htlcs: usize) -> u64 { + fn commit_tx_fee_msat(feerate_per_kw: u32, num_htlcs: usize) -> 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 + num_htlcs as u64 * COMMITMENT_TX_WEIGHT_PER_HTLC) * self.feerate_per_kw as u64 / 1000 * 1000 + (COMMITMENT_TX_BASE_WEIGHT + num_htlcs as u64 * COMMITMENT_TX_WEIGHT_PER_HTLC) * feerate_per_kw as u64 / 1000 * 1000 } // Get the fee cost in SATS of a commitment tx with a given number of HTLC outputs. @@ -2162,12 +2202,12 @@ impl Channel { } let num_htlcs = included_htlcs + addl_htlcs; - let res = self.commit_tx_fee_msat(num_htlcs); + let res = Self::commit_tx_fee_msat(self.feerate_per_kw, num_htlcs); #[cfg(any(test, feature = "fuzztarget"))] { let mut fee = res; if fee_spike_buffer_htlc.is_some() { - fee = self.commit_tx_fee_msat(num_htlcs - 1); + fee = Self::commit_tx_fee_msat(self.feerate_per_kw, num_htlcs - 1); } let total_pending_htlcs = self.pending_inbound_htlcs.len() + self.pending_outbound_htlcs.len() + self.holding_cell_htlc_updates.len(); @@ -2240,12 +2280,12 @@ impl Channel { } let num_htlcs = included_htlcs + addl_htlcs; - let res = self.commit_tx_fee_msat(num_htlcs); + let res = Self::commit_tx_fee_msat(self.feerate_per_kw, num_htlcs); #[cfg(any(test, feature = "fuzztarget"))] { let mut fee = res; if fee_spike_buffer_htlc.is_some() { - fee = self.commit_tx_fee_msat(num_htlcs - 1); + fee = Self::commit_tx_fee_msat(self.feerate_per_kw, num_htlcs - 1); } let total_pending_htlcs = self.pending_inbound_htlcs.len() + self.pending_outbound_htlcs.len(); let commitment_tx_info = CommitmentTxInfoCached { @@ -2291,8 +2331,8 @@ impl Channel { return Err(ChannelError::Close(format!("Remote side tried to send less than our minimum HTLC value. Lower limit: ({}). Actual: ({})", self.holder_htlc_minimum_msat, msg.amount_msat))); } - let inbound_stats = self.get_inbound_pending_htlc_stats(); - let outbound_stats = self.get_outbound_pending_htlc_stats(); + let inbound_stats = self.get_inbound_pending_htlc_stats(None); + let outbound_stats = self.get_outbound_pending_htlc_stats(None); if inbound_stats.pending_htlcs + 1 > OUR_MAX_HTLCS as u32 { return Err(ChannelError::Close(format!("Remote tried to push more than our max accepted HTLCs ({})", OUR_MAX_HTLCS))); } @@ -2321,7 +2361,7 @@ impl Channel { } } - let exposure_dust_limit_timeout_sats = (self.get_dust_buffer_feerate() as u64 * HTLC_TIMEOUT_TX_WEIGHT / 1000) + self.counterparty_dust_limit_satoshis; + let exposure_dust_limit_timeout_sats = (self.get_dust_buffer_feerate(None) as u64 * HTLC_TIMEOUT_TX_WEIGHT / 1000) + self.counterparty_dust_limit_satoshis; if msg.amount_msat / 1000 < exposure_dust_limit_timeout_sats { let on_counterparty_tx_dust_htlc_exposure_msat = inbound_stats.on_counterparty_tx_dust_exposure_msat + outbound_stats.on_counterparty_tx_dust_exposure_msat + msg.amount_msat; if on_counterparty_tx_dust_htlc_exposure_msat > self.get_max_dust_htlc_exposure_msat() { @@ -2331,7 +2371,7 @@ impl Channel { } } - let exposure_dust_limit_success_sats = (self.get_dust_buffer_feerate() as u64 * HTLC_SUCCESS_TX_WEIGHT / 1000) + self.holder_dust_limit_satoshis; + let exposure_dust_limit_success_sats = (self.get_dust_buffer_feerate(None) as u64 * HTLC_SUCCESS_TX_WEIGHT / 1000) + self.holder_dust_limit_satoshis; if msg.amount_msat / 1000 < exposure_dust_limit_success_sats { let on_holder_tx_dust_htlc_exposure_msat = inbound_stats.on_holder_tx_dust_exposure_msat + outbound_stats.on_holder_tx_dust_exposure_msat + msg.amount_msat; if on_holder_tx_dust_htlc_exposure_msat > self.get_max_dust_htlc_exposure_msat() { @@ -2495,36 +2535,32 @@ impl Channel { let keys = self.build_holder_transaction_keys(self.cur_holder_commitment_transaction_number).map_err(|e| (None, e))?; - let (num_htlcs, mut htlcs_cloned, commitment_tx, commitment_txid, feerate_per_kw, _, counterparty_balance_msat) = { - let commitment_tx = self.build_commitment_transaction(self.cur_holder_commitment_transaction_number, &keys, true, false, logger); - let commitment_txid = { - let trusted_tx = commitment_tx.0.trust(); - let bitcoin_tx = trusted_tx.built_transaction(); - let sighash = bitcoin_tx.get_sighash_all(&funding_script, self.channel_value_satoshis); - - log_trace!(logger, "Checking commitment tx signature {} by key {} against tx {} (sighash {}) with redeemscript {} in channel {}", - log_bytes!(msg.signature.serialize_compact()[..]), - log_bytes!(self.counterparty_funding_pubkey().serialize()), encode::serialize_hex(&bitcoin_tx.transaction), - log_bytes!(sighash[..]), encode::serialize_hex(&funding_script), log_bytes!(self.channel_id())); - if let Err(_) = self.secp_ctx.verify(&sighash, &msg.signature, &self.counterparty_funding_pubkey()) { - return Err((None, ChannelError::Close("Invalid commitment tx signature from peer".to_owned()))); - } - bitcoin_tx.txid - }; - let htlcs_cloned: Vec<_> = commitment_tx.3.iter().map(|htlc| (htlc.0.clone(), htlc.1.map(|h| h.clone()))).collect(); - (commitment_tx.2, htlcs_cloned, commitment_tx.0, commitment_txid, commitment_tx.1, commitment_tx.4, commitment_tx.5) + let commitment_stats = self.build_commitment_transaction(self.cur_holder_commitment_transaction_number, &keys, true, false, logger); + let commitment_txid = { + let trusted_tx = commitment_stats.tx.trust(); + let bitcoin_tx = trusted_tx.built_transaction(); + let sighash = bitcoin_tx.get_sighash_all(&funding_script, self.channel_value_satoshis); + + log_trace!(logger, "Checking commitment tx signature {} by key {} against tx {} (sighash {}) with redeemscript {} in channel {}", + log_bytes!(msg.signature.serialize_compact()[..]), + log_bytes!(self.counterparty_funding_pubkey().serialize()), encode::serialize_hex(&bitcoin_tx.transaction), + log_bytes!(sighash[..]), encode::serialize_hex(&funding_script), log_bytes!(self.channel_id())); + if let Err(_) = self.secp_ctx.verify(&sighash, &msg.signature, &self.counterparty_funding_pubkey()) { + return Err((None, ChannelError::Close("Invalid commitment tx signature from peer".to_owned()))); + } + bitcoin_tx.txid }; + let mut htlcs_cloned: Vec<_> = commitment_stats.htlcs_included.iter().map(|htlc| (htlc.0.clone(), htlc.1.map(|h| h.clone()))).collect(); // If our counterparty updated the channel fee in this commitment transaction, check that // they can actually afford the new fee now. let update_fee = if let Some((_, update_state)) = self.pending_update_fee { update_state == FeeUpdateState::RemoteAnnounced } else { false }; - if update_fee { debug_assert!(!self.is_outbound()); } - let total_fee_sat = Channel::::commit_tx_fee_sat(feerate_per_kw, num_htlcs); if update_fee { - let counterparty_reserve_we_require = Channel::::get_holder_selected_channel_reserve_satoshis(self.channel_value_satoshis); - if counterparty_balance_msat < total_fee_sat * 1000 + counterparty_reserve_we_require * 1000 { + debug_assert!(!self.is_outbound()); + let counterparty_reserve_we_require_msat = Channel::::get_holder_selected_channel_reserve_satoshis(self.channel_value_satoshis) * 1000; + if commitment_stats.remote_balance_msat < commitment_stats.total_fee_sat * 1000 + counterparty_reserve_we_require_msat { return Err((None, ChannelError::Close("Funding remote cannot afford proposed new fee".to_owned()))); } } @@ -2540,25 +2576,25 @@ impl Channel { && info.next_holder_htlc_id == self.next_holder_htlc_id && info.next_counterparty_htlc_id == self.next_counterparty_htlc_id && info.feerate == self.feerate_per_kw { - assert_eq!(total_fee_sat, info.fee / 1000); + assert_eq!(commitment_stats.total_fee_sat, info.fee / 1000); } } } } - if msg.htlc_signatures.len() != num_htlcs { - return Err((None, ChannelError::Close(format!("Got wrong number of HTLC signatures ({}) from remote. It must be {}", msg.htlc_signatures.len(), num_htlcs)))); + if msg.htlc_signatures.len() != commitment_stats.num_nondust_htlcs { + return Err((None, ChannelError::Close(format!("Got wrong number of HTLC signatures ({}) from remote. It must be {}", msg.htlc_signatures.len(), commitment_stats.num_nondust_htlcs)))); } // TODO: Sadly, we pass HTLCs twice to ChannelMonitor: once via the HolderCommitmentTransaction and once via the update let mut htlcs_and_sigs = Vec::with_capacity(htlcs_cloned.len()); for (idx, (htlc, source)) in htlcs_cloned.drain(..).enumerate() { if let Some(_) = htlc.transaction_output_index { - let htlc_tx = chan_utils::build_htlc_transaction(&commitment_txid, feerate_per_kw, - self.get_counterparty_selected_contest_delay().unwrap(), &htlc, + let htlc_tx = chan_utils::build_htlc_transaction(&commitment_txid, commitment_stats.feerate_per_kw, + self.get_counterparty_selected_contest_delay().unwrap(), &htlc, self.opt_anchors(), &keys.broadcaster_delayed_payment_key, &keys.revocation_key); - let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, &keys); + let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, self.opt_anchors(), &keys); let htlc_sighash = hash_to_message!(&bip143::SigHashCache::new(&htlc_tx).signature_hash(0, &htlc_redeemscript, htlc.amount_msat / 1000, SigHashType::All)[..]); log_trace!(logger, "Checking HTLC tx signature {} by key {} against tx {} (sighash {}) with redeemscript {} in channel {}.", log_bytes!(msg.htlc_signatures[idx].serialize_compact()[..]), log_bytes!(keys.countersignatory_htlc_key.serialize()), @@ -2573,7 +2609,7 @@ impl Channel { } let holder_commitment_tx = HolderCommitmentTransaction::new( - commitment_tx, + commitment_stats.tx, msg.signature, msg.htlc_signatures.clone(), &self.get_holder_pubkeys().funding_pubkey, @@ -3080,18 +3116,30 @@ 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(); - let outbound_stats = self.get_outbound_pending_htlc_stats(); + 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 = if let Ok(keys) = self.build_holder_transaction_keys(self.cur_holder_commitment_transaction_number) { keys } else { return None; }; - let (_, _, num_htlcs, _, holder_balance_msat, _) = self.build_commitment_transaction(self.cur_holder_commitment_transaction_number, &keys, true, true, logger); - let total_fee_sat = Channel::::commit_tx_fee_sat(feerate_per_kw, num_htlcs + CONCURRENT_INBOUND_HTLC_FEE_BUFFER as usize); - let holder_balance_msat = holder_balance_msat - outbound_stats.holding_cell_msat; - if holder_balance_msat < total_fee_sat * 1000 + self.counterparty_selected_channel_reserve_satoshis.unwrap() * 1000 { + let commitment_stats = self.build_commitment_transaction(self.cur_holder_commitment_transaction_number, &keys, true, true, logger); + let buffer_fee_msat = Channel::::commit_tx_fee_sat(feerate_per_kw, commitment_stats.num_nondust_htlcs + outbound_stats.on_holder_tx_holding_cell_htlcs_count as usize + CONCURRENT_INBOUND_HTLC_FEE_BUFFER as usize) * 1000; + let holder_balance_msat = commitment_stats.local_balance_msat - outbound_stats.holding_cell_msat; + if holder_balance_msat < buffer_fee_msat + self.counterparty_selected_channel_reserve_satoshis.unwrap() * 1000 { //TODO: auto-close after a number of failures? log_debug!(logger, "Cannot afford to send new feerate at {}", feerate_per_kw); return None; } + // Note, we evaluate pending htlc "preemptive" trimmed-to-dust threshold at the proposed `feerate_per_kw`. + let holder_tx_dust_exposure = inbound_stats.on_holder_tx_dust_exposure_msat + outbound_stats.on_holder_tx_dust_exposure_msat; + let counterparty_tx_dust_exposure = inbound_stats.on_counterparty_tx_dust_exposure_msat + outbound_stats.on_counterparty_tx_dust_exposure_msat; + if holder_tx_dust_exposure > self.get_max_dust_htlc_exposure_msat() { + log_debug!(logger, "Cannot afford to send new feerate at {} without infringing max dust htlc exposure", feerate_per_kw); + return None; + } + if counterparty_tx_dust_exposure > self.get_max_dust_htlc_exposure_msat() { + log_debug!(logger, "Cannot afford to send new feerate at {} without infringing max dust htlc exposure", feerate_per_kw); + return None; + } + if (self.channel_state & (ChannelState::AwaitingRemoteRevoke as u32 | ChannelState::MonitorUpdateFailed as u32)) != 0 { self.holding_cell_update_fee = Some(feerate_per_kw); return None; @@ -3271,7 +3319,7 @@ 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)?; - let feerate_over_dust_buffer = msg.feerate_per_kw > self.get_dust_buffer_feerate(); + let feerate_over_dust_buffer = msg.feerate_per_kw > self.get_dust_buffer_feerate(None); self.pending_update_fee = Some((msg.feerate_per_kw, FeeUpdateState::RemoteAnnounced)); self.update_time_counter += 1; @@ -3279,8 +3327,8 @@ 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(); - let outbound_stats = self.get_outbound_pending_htlc_stats(); + let inbound_stats = self.get_inbound_pending_htlc_stats(None); + let outbound_stats = self.get_outbound_pending_htlc_stats(None); let holder_tx_dust_exposure = inbound_stats.on_holder_tx_dust_exposure_msat + outbound_stats.on_holder_tx_dust_exposure_msat; let counterparty_tx_dust_exposure = inbound_stats.on_counterparty_tx_dust_exposure_msat + outbound_stats.on_counterparty_tx_dust_exposure_msat; if holder_tx_dust_exposure > self.get_max_dust_htlc_exposure_msat() { @@ -3981,7 +4029,7 @@ impl Channel { self.feerate_per_kw } - pub fn get_dust_buffer_feerate(&self) -> u32 { + 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 @@ -3993,6 +4041,9 @@ impl Channel { 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) } @@ -4409,7 +4460,7 @@ 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_initial_commitment_tx = self.build_commitment_transaction(self.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, false, logger).0; + let counterparty_initial_commitment_tx = self.build_commitment_transaction(self.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, false, logger).tx; Ok(self.holder_signer.sign_counterparty_commitment(&counterparty_initial_commitment_tx, &self.secp_ctx) .map_err(|_| ChannelError::Close("Failed to get signatures for new commitment_signed".to_owned()))?.0) } @@ -4655,8 +4706,8 @@ impl Channel { return Err(ChannelError::Ignore("Cannot send an HTLC while disconnected from channel counterparty".to_owned())); } - let inbound_stats = self.get_inbound_pending_htlc_stats(); - let outbound_stats = self.get_outbound_pending_htlc_stats(); + let inbound_stats = self.get_inbound_pending_htlc_stats(None); + let outbound_stats = self.get_outbound_pending_htlc_stats(None); if outbound_stats.pending_htlcs + 1 > self.counterparty_max_accepted_htlcs as u32 { return Err(ChannelError::Ignore(format!("Cannot push more than their max accepted HTLCs ({})", self.counterparty_max_accepted_htlcs))); } @@ -4666,18 +4717,18 @@ impl Channel { } let keys = self.build_holder_transaction_keys(self.cur_holder_commitment_transaction_number)?; + let commitment_stats = self.build_commitment_transaction(self.cur_holder_commitment_transaction_number, &keys, true, true, logger); if !self.is_outbound() { // Check that we won't violate the remote channel reserve by adding this HTLC. - let counterparty_balance_msat = self.build_commitment_transaction(self.cur_holder_commitment_transaction_number, &keys, true, true, logger).5; let htlc_candidate = HTLCCandidate::new(amount_msat, HTLCInitiator::LocalOffered); let counterparty_commit_tx_fee_msat = self.next_remote_commit_tx_fee_msat(htlc_candidate, None); let holder_selected_chan_reserve_msat = Channel::::get_holder_selected_channel_reserve_satoshis(self.channel_value_satoshis) * 1000; - if counterparty_balance_msat < counterparty_commit_tx_fee_msat + holder_selected_chan_reserve_msat { + if commitment_stats.remote_balance_msat < counterparty_commit_tx_fee_msat + holder_selected_chan_reserve_msat { return Err(ChannelError::Ignore("Cannot send value that would put counterparty balance under holder-announced channel reserve value".to_owned())); } } - let exposure_dust_limit_success_sats = (self.get_dust_buffer_feerate() as u64 * HTLC_SUCCESS_TX_WEIGHT / 1000) + self.counterparty_dust_limit_satoshis; + let exposure_dust_limit_success_sats = (self.get_dust_buffer_feerate(None) as u64 * HTLC_SUCCESS_TX_WEIGHT / 1000) + self.counterparty_dust_limit_satoshis; if amount_msat / 1000 < exposure_dust_limit_success_sats { let on_counterparty_dust_htlc_exposure_msat = inbound_stats.on_counterparty_tx_dust_exposure_msat + outbound_stats.on_counterparty_tx_dust_exposure_msat + amount_msat; if on_counterparty_dust_htlc_exposure_msat > self.get_max_dust_htlc_exposure_msat() { @@ -4686,7 +4737,7 @@ impl Channel { } } - let exposure_dust_limit_timeout_sats = (self.get_dust_buffer_feerate() as u64 * HTLC_TIMEOUT_TX_WEIGHT / 1000) + self.holder_dust_limit_satoshis; + let exposure_dust_limit_timeout_sats = (self.get_dust_buffer_feerate(None) as u64 * HTLC_TIMEOUT_TX_WEIGHT / 1000) + self.holder_dust_limit_satoshis; if amount_msat / 1000 < exposure_dust_limit_timeout_sats { let on_holder_dust_htlc_exposure_msat = inbound_stats.on_holder_tx_dust_exposure_msat + outbound_stats.on_holder_tx_dust_exposure_msat + amount_msat; if on_holder_dust_htlc_exposure_msat > self.get_max_dust_htlc_exposure_msat() { @@ -4695,7 +4746,7 @@ impl Channel { } } - let holder_balance_msat = self.build_commitment_transaction(self.cur_holder_commitment_transaction_number, &keys, true, true, logger).4 as u64 - outbound_stats.holding_cell_msat; + let holder_balance_msat = commitment_stats.local_balance_msat - outbound_stats.holding_cell_msat; if holder_balance_msat < amount_msat { return Err(ChannelError::Ignore(format!("Cannot send value that would overdraw remaining funds. Amount: {}, pending value to self {}", amount_msat, holder_balance_msat))); } @@ -4846,9 +4897,8 @@ impl Channel { /// when we shouldn't change HTLC/channel state. fn send_commitment_no_state_update(&self, logger: &L) -> Result<(msgs::CommitmentSigned, (Txid, Vec<(HTLCOutputInCommitment, Option<&HTLCSource>)>)), ChannelError> where L::Target: Logger { let counterparty_keys = self.build_remote_transaction_keys()?; - let counterparty_commitment_tx = self.build_commitment_transaction(self.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, true, logger); - let feerate_per_kw = counterparty_commitment_tx.1; - let counterparty_commitment_txid = counterparty_commitment_tx.0.trust().txid(); + let commitment_stats = self.build_commitment_transaction(self.cur_counterparty_commitment_transaction_number, &counterparty_keys, false, true, logger); + let counterparty_commitment_txid = commitment_stats.tx.trust().txid(); let (signature, htlc_signatures); #[cfg(any(test, feature = "fuzztarget"))] @@ -4862,7 +4912,7 @@ impl Channel { && info.next_holder_htlc_id == self.next_holder_htlc_id && info.next_counterparty_htlc_id == self.next_counterparty_htlc_id && info.feerate == self.feerate_per_kw { - let actual_fee = self.commit_tx_fee_msat(counterparty_commitment_tx.2); + let actual_fee = Self::commit_tx_fee_msat(self.feerate_per_kw, commitment_stats.num_nondust_htlcs); assert_eq!(actual_fee, info.fee); } } @@ -4870,25 +4920,25 @@ impl Channel { } { - let mut htlcs = Vec::with_capacity(counterparty_commitment_tx.3.len()); - for &(ref htlc, _) in counterparty_commitment_tx.3.iter() { + let mut htlcs = Vec::with_capacity(commitment_stats.htlcs_included.len()); + for &(ref htlc, _) in commitment_stats.htlcs_included.iter() { htlcs.push(htlc); } - let res = self.holder_signer.sign_counterparty_commitment(&counterparty_commitment_tx.0, &self.secp_ctx) + let res = self.holder_signer.sign_counterparty_commitment(&commitment_stats.tx, &self.secp_ctx) .map_err(|_| ChannelError::Close("Failed to get signatures for new commitment_signed".to_owned()))?; signature = res.0; htlc_signatures = res.1; log_trace!(logger, "Signed remote commitment tx {} (txid {}) with redeemscript {} -> {} in channel {}", - encode::serialize_hex(&counterparty_commitment_tx.0.trust().built_transaction().transaction), + encode::serialize_hex(&commitment_stats.tx.trust().built_transaction().transaction), &counterparty_commitment_txid, encode::serialize_hex(&self.get_funding_redeemscript()), log_bytes!(signature.serialize_compact()[..]), log_bytes!(self.channel_id())); for (ref htlc_sig, ref htlc) in htlc_signatures.iter().zip(htlcs) { log_trace!(logger, "Signed remote HTLC tx {} with redeemscript {} with pubkey {} -> {} in channel {}", - encode::serialize_hex(&chan_utils::build_htlc_transaction(&counterparty_commitment_txid, feerate_per_kw, self.get_holder_selected_contest_delay(), htlc, &counterparty_keys.broadcaster_delayed_payment_key, &counterparty_keys.revocation_key)), - encode::serialize_hex(&chan_utils::get_htlc_redeemscript(&htlc, &counterparty_keys)), + encode::serialize_hex(&chan_utils::build_htlc_transaction(&counterparty_commitment_txid, commitment_stats.feerate_per_kw, self.get_holder_selected_contest_delay(), htlc, self.opt_anchors(), &counterparty_keys.broadcaster_delayed_payment_key, &counterparty_keys.revocation_key)), + encode::serialize_hex(&chan_utils::get_htlc_redeemscript(&htlc, self.opt_anchors(), &counterparty_keys)), log_bytes!(counterparty_keys.broadcaster_htlc_key.serialize()), log_bytes!(htlc_sig.serialize_compact()[..]), log_bytes!(self.channel_id())); } @@ -4898,7 +4948,7 @@ impl Channel { channel_id: self.channel_id, signature, htlc_signatures, - }, (counterparty_commitment_txid, counterparty_commitment_tx.3))) + }, (counterparty_commitment_txid, commitment_stats.htlcs_included))) } /// Adds a pending outbound HTLC to this channel, and creates a signed commitment transaction @@ -5592,6 +5642,11 @@ impl<'a, Signer: Sign, K: Deref> ReadableArgs<(&'a K, u32)> for Channel return Err(DecodeError::UnknownRequiredFeature); } + if channel_parameters.opt_anchors.is_some() { + // Relax this check when ChannelTypeFeatures supports anchors. + return Err(DecodeError::InvalidValue); + } + let mut secp_ctx = Secp256k1::new(); secp_ctx.seeded_randomize(&keys_source.get_secure_random_bytes()); @@ -5887,13 +5942,13 @@ mod tests { // 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 = node_a_chan.commit_tx_fee_msat(0); + let local_commit_fee_0_htlcs = Channel::::commit_tx_fee_msat(node_a_chan.feerate_per_kw, 0); 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.channel_transaction_parameters.is_outbound_from_holder = false; - let remote_commit_fee_3_htlcs = node_a_chan.commit_tx_fee_msat(3); + let remote_commit_fee_3_htlcs = Channel::::commit_tx_fee_msat(node_a_chan.feerate_per_kw, 3); 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); assert_eq!(remote_commit_tx_fee, remote_commit_fee_3_htlcs); @@ -5915,8 +5970,8 @@ mod tests { let config = UserConfig::default(); let mut chan = Channel::::new_outbound(&&fee_est, &&keys_provider, node_id, &InitFeatures::known(), 10000000, 100000, 42, &config, 0).unwrap(); - let commitment_tx_fee_0_htlcs = chan.commit_tx_fee_msat(0); - let commitment_tx_fee_1_htlc = chan.commit_tx_fee_msat(1); + let commitment_tx_fee_0_htlcs = Channel::::commit_tx_fee_msat(chan.feerate_per_kw, 0); + let commitment_tx_fee_1_htlc = Channel::::commit_tx_fee_msat(chan.feerate_per_kw, 1); // 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. @@ -6132,12 +6187,12 @@ mod tests { $( { $htlc_idx: expr, $counterparty_htlc_sig_hex: expr, $htlc_sig_hex: expr, $htlc_tx_hex: expr } ), * } ) => { { let (commitment_tx, htlcs): (_, Vec) = { - let mut res = chan.build_commitment_transaction(0xffffffffffff - 42, &keys, true, false, &logger); + let mut commitment_stats = chan.build_commitment_transaction(0xffffffffffff - 42, &keys, true, false, &logger); - let htlcs = res.3.drain(..) + let htlcs = commitment_stats.htlcs_included.drain(..) .filter_map(|(htlc, _)| if htlc.transaction_output_index.is_some() { Some(htlc) } else { None }) .collect(); - (res.0, htlcs) + (commitment_stats.tx, htlcs) }; let trusted_tx = commitment_tx.trust(); let unsigned_tx = trusted_tx.built_transaction(); @@ -6178,10 +6233,11 @@ mod tests { let remote_signature = Signature::from_der(&hex::decode($counterparty_htlc_sig_hex).unwrap()[..]).unwrap(); let ref htlc = htlcs[$htlc_idx]; + let opt_anchors = false; let htlc_tx = chan_utils::build_htlc_transaction(&unsigned_tx.txid, chan.feerate_per_kw, chan.get_counterparty_selected_contest_delay().unwrap(), - &htlc, &keys.broadcaster_delayed_payment_key, &keys.revocation_key); - let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, &keys); + &htlc, opt_anchors, &keys.broadcaster_delayed_payment_key, &keys.revocation_key); + let htlc_redeemscript = chan_utils::get_htlc_redeemscript(&htlc, opt_anchors, &keys); let htlc_sighash = Message::from_slice(&bip143::SigHashCache::new(&htlc_tx).signature_hash(0, &htlc_redeemscript, htlc.amount_msat / 1000, SigHashType::All)[..]).unwrap(); secp_ctx.verify(&htlc_sighash, &remote_signature, &keys.countersignatory_htlc_key).unwrap();