From: Valentine Wallace Date: Fri, 4 Dec 2020 21:05:10 +0000 (-0500) Subject: Don't include below-dust inbound HTLCs in commit tx fee calculation X-Git-Tag: v0.0.13~26^2~1 X-Git-Url: http://git.bitcoin.ninja/?a=commitdiff_plain;h=3d4735cc0a51800318d8abc1253e4ef5b43e590a;p=rust-lightning Don't include below-dust inbound HTLCs in commit tx fee calculation Also remove part of the holding cell channel reserve test that's newly failing but a bit of a redundant test anyway. --- diff --git a/lightning/src/ln/channel.rs b/lightning/src/ln/channel.rs index e700b1f3b..316c6721b 100644 --- a/lightning/src/ln/channel.rs +++ b/lightning/src/ln/channel.rs @@ -258,6 +258,27 @@ enum UpdateStatus { DisabledStaged, } +/// An enum indicating whether the local or remote side offered a given HTLC. +enum HTLCInitiator { + LocalOffered, + RemoteOffered, +} + +/// Used when calculating whether we or the remote can afford an additional HTLC. +struct HTLCCandidate { + amount_msat: u64, + origin: HTLCInitiator, +} + +impl HTLCCandidate { + fn new(amount_msat: u64, origin: HTLCInitiator) -> Self { + Self { + amount_msat, + origin, + } + } +} + // 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 @@ -1684,63 +1705,122 @@ impl Channel { (COMMITMENT_TX_BASE_WEIGHT + num_htlcs as u64 * COMMITMENT_TX_WEIGHT_PER_HTLC) * self.feerate_per_kw as u64 / 1000 * 1000 } - // Get the commitment tx fee for the local (i.e our) next commitment transaction - // based on the number of pending HTLCs that are on track to be in our next - // commitment tx. `addl_htcs` is an optional parameter allowing the caller - // to add a number of additional HTLCs to the calculation. Note that dust - // HTLCs are excluded. - fn next_local_commit_tx_fee_msat(&self, addl_htlcs: usize) -> u64 { + // 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, plus an additional + // HTLC if `fee_spike_buffer_htlc` is Some, plus a new HTLC given by `new_htlc_amount`. Dust HTLCs + // are excluded. + fn next_local_commit_tx_fee_msat(&self, htlc: HTLCCandidate, fee_spike_buffer_htlc: Option<()>) -> u64 { assert!(self.is_outbound()); - let mut their_acked_htlcs = self.pending_inbound_htlcs.len(); + let real_dust_limit_success_sat = (self.feerate_per_kw as u64 * HTLC_SUCCESS_TX_WEIGHT / 1000) + self.holder_dust_limit_satoshis; + let real_dust_limit_timeout_sat = (self.feerate_per_kw as u64 * HTLC_TIMEOUT_TX_WEIGHT / 1000) + self.holder_dust_limit_satoshis; + + 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 mut included_htlcs = 0; + for ref htlc in self.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; + } + for ref htlc in self.pending_outbound_htlcs.iter() { - if htlc.amount_msat / 1000 <= self.holder_dust_limit_satoshis { + if htlc.amount_msat / 1000 < real_dust_limit_timeout_sat { continue } match htlc.state { - OutboundHTLCState::Committed => their_acked_htlcs += 1, - OutboundHTLCState::RemoteRemoved {..} => their_acked_htlcs += 1, - OutboundHTLCState::LocalAnnounced {..} => their_acked_htlcs += 1, + 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. _ => {}, } } for htlc in self.holding_cell_htlc_updates.iter() { match htlc { - &HTLCUpdateAwaitingACK::AddHTLC { .. } => their_acked_htlcs += 1, - _ => {}, + &HTLCUpdateAwaitingACK::AddHTLC { amount_msat, .. } => { + if amount_msat / 1000 < real_dust_limit_timeout_sat { + continue + } + included_htlcs += 1 + }, + _ => {}, // Don't include claims/fails that are awaiting ack, because once we get the + // ack we're guaranteed to never include them in commitment txs anymore. } } - self.commit_tx_fee_msat(their_acked_htlcs + addl_htlcs) + self.commit_tx_fee_msat(included_htlcs + addl_htlcs) } - // 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. `addl_htcs` is an optional parameter allowing the caller - // to add a number of additional HTLCs to the calculation. Note that dust HTLCs - // are excluded. - fn next_remote_commit_tx_fee_msat(&self, addl_htlcs: usize) -> u64 { + // 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, plus an additional HTLC if + // `fee_spike_buffer_htlc` is Some, plus a new HTLC given by `new_htlc_amount`. Dust HTLCs are + // excluded. + fn next_remote_commit_tx_fee_msat(&self, htlc: HTLCCandidate, fee_spike_buffer_htlc: Option<()>) -> u64 { assert!(!self.is_outbound()); - // When calculating the set of HTLCs which will be included in their next - // commitment_signed, all inbound HTLCs are included (as all states imply it will be - // included) and only committed outbound HTLCs, see below. - let mut their_acked_htlcs = self.pending_inbound_htlcs.len(); + let real_dust_limit_success_sat = (self.feerate_per_kw as u64 * HTLC_SUCCESS_TX_WEIGHT / 1000) + self.counterparty_dust_limit_satoshis; + let real_dust_limit_timeout_sat = (self.feerate_per_kw as u64 * HTLC_TIMEOUT_TX_WEIGHT / 1000) + self.counterparty_dust_limit_satoshis; + + 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.pending_inbound_htlcs.iter() { + if htlc.amount_msat / 1000 <= real_dust_limit_timeout_sat { + continue + } + included_htlcs += 1; + } + for ref htlc in self.pending_outbound_htlcs.iter() { - if htlc.amount_msat / 1000 <= self.counterparty_dust_limit_satoshis { + 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. + // 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 => their_acked_htlcs += 1, - OutboundHTLCState::RemoteRemoved {..} => their_acked_htlcs += 1, + OutboundHTLCState::Committed => included_htlcs += 1, + OutboundHTLCState::RemoteRemoved {..} => included_htlcs += 1, _ => {}, } } - self.commit_tx_fee_msat(their_acked_htlcs + addl_htlcs) + self.commit_tx_fee_msat(included_htlcs + addl_htlcs) } pub fn update_add_htlc(&mut self, msg: &msgs::UpdateAddHTLC, mut pending_forward_status: PendingHTLCStatus, create_pending_htlc_status: F, logger: &L) -> Result<(), ChannelError> @@ -1808,8 +1888,8 @@ impl Channel { // Check that the remote can afford to pay for this HTLC on-chain at the current // feerate_per_kw, while maintaining their channel reserve (as required by the spec). let remote_commit_tx_fee_msat = if self.is_outbound() { 0 } else { - // +1 for this HTLC. - self.next_remote_commit_tx_fee_msat(1) + 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 }; 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())); @@ -1822,14 +1902,16 @@ impl Channel { } if !self.is_outbound() { - // `+1` for this HTLC, `2 *` and `+1` fee spike buffer we keep for the remote. This deviates from the - // spec because in the spec, the fee spike buffer requirement doesn't exist on the receiver's side, - // only on the sender's. - // Note that when we eventually remove support for fee updates and switch to anchor output fees, - // we will drop the `2 *`, since we no longer be as sensitive to fee spikes. But, keep the extra +1 - // as we should still be able to afford adding this HTLC plus one more future HTLC, regardless of - // being sensitive to fee spikes. - let remote_fee_cost_incl_stuck_buffer_msat = 2 * self.next_remote_commit_tx_fee_msat(1 + 1); + // `2 *` and `Some(())` is for the fee spike buffer we keep for the remote. This deviates from + // the spec because in the spec, the fee spike buffer requirement doesn't exist on the + // receiver's side, only on the sender's. + // Note that when we eventually remove support for fee updates and switch to anchor output + // fees, we will drop the `2 *`, since we no longer be as sensitive to fee spikes. But, keep + // the extra htlc when calculating the next remote commitment transaction fee as we should + // 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(())); if pending_remote_value_msat - msg.amount_msat - chan_reserve_msat < 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. @@ -1838,9 +1920,8 @@ impl Channel { } } else { // Check that they won't violate our local required channel reserve by adding this HTLC. - - // +1 for this HTLC. - let local_commit_tx_fee_msat = self.next_local_commit_tx_fee_msat(1); + 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); if self.value_to_self_msat < self.counterparty_selected_channel_reserve_satoshis * 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())); } @@ -3720,11 +3801,10 @@ impl Channel { if !self.is_outbound() { // Check that we won't violate the remote channel reserve by adding this HTLC. - let counterparty_balance_msat = self.channel_value_satoshis * 1000 - self.value_to_self_msat; let holder_selected_chan_reserve_msat = Channel::::get_holder_selected_channel_reserve_satoshis(self.channel_value_satoshis); - // 1 additional HTLC corresponding to this HTLC. - let counterparty_commit_tx_fee_msat = self.next_remote_commit_tx_fee_msat(1); + 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); if counterparty_balance_msat < holder_selected_chan_reserve_msat + counterparty_commit_tx_fee_msat { return Err(ChannelError::Ignore("Cannot send value that would put counterparty balance under holder-announced channel reserve value".to_owned())); } @@ -3735,10 +3815,10 @@ impl Channel { return Err(ChannelError::Ignore(format!("Cannot send value that would overdraw remaining funds. Amount: {}, pending value to self {}", amount_msat, pending_value_to_self_msat))); } - // The `+1` is for the HTLC currently being added to the commitment tx and - // the `2 *` and `+1` are for the fee spike buffer. + // `2 *` and extra HTLC are for the fee spike buffer. let commit_tx_fee_msat = if self.is_outbound() { - 2 * self.next_local_commit_tx_fee_msat(1 + 1) + let htlc_candidate = HTLCCandidate::new(amount_msat, HTLCInitiator::LocalOffered); + 2 * self.next_local_commit_tx_fee_msat(htlc_candidate, Some(())) } else { 0 }; if pending_value_to_self_msat - amount_msat < commit_tx_fee_msat { return Err(ChannelError::Ignore(format!("Cannot send value that would not leave enough to pay for fees. Pending value to self: {}. local_commit_tx_fee {}", pending_value_to_self_msat, commit_tx_fee_msat))); @@ -4487,12 +4567,12 @@ mod tests { use bitcoin::hashes::hex::FromHex; use hex; use ln::channelmanager::{HTLCSource, PaymentPreimage, PaymentHash}; - use ln::channel::{Channel,ChannelKeys,InboundHTLCOutput,OutboundHTLCOutput,InboundHTLCState,OutboundHTLCState,HTLCOutputInCommitment,TxCreationKeys}; + use ln::channel::{Channel,ChannelKeys,InboundHTLCOutput,OutboundHTLCOutput,InboundHTLCState,OutboundHTLCState,HTLCOutputInCommitment,HTLCCandidate,HTLCInitiator,TxCreationKeys}; use ln::channel::MAX_FUNDING_SATOSHIS; use ln::features::InitFeatures; use ln::msgs::{OptionalField, DataLossProtect, DecodeError}; use ln::chan_utils; - use ln::chan_utils::{ChannelPublicKeys, HolderCommitmentTransaction, CounterpartyChannelTransactionParameters}; + use ln::chan_utils::{ChannelPublicKeys, HolderCommitmentTransaction, CounterpartyChannelTransactionParameters, HTLC_SUCCESS_TX_WEIGHT, HTLC_TIMEOUT_TX_WEIGHT}; use chain::chaininterface::{FeeEstimator,ConfirmationTarget}; use chain::keysinterface::{InMemoryChannelKeys, KeysInterface}; use chain::transaction::OutPoint; @@ -4575,6 +4655,122 @@ mod tests { assert_eq!(open_channel_msg.feerate_per_kw, original_fee); } + #[test] + fn test_holder_vs_counterparty_dust_limit() { + // Test that when calculating the local and remote commitment transaction fees, the correct + // dust limits are used. + let feeest = TestFeeEstimator{fee_est: 15000}; + let secp_ctx = Secp256k1::new(); + let seed = [42; 32]; + let network = Network::Testnet; + let keys_provider = test_utils::TestKeysInterface::new(&seed, network); + + // Go through the flow of opening a channel between two nodes, making sure + // they have different dust limits. + + // Create Node A's channel pointing to Node B's pubkey + let node_b_node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap()); + let config = UserConfig::default(); + let mut node_a_chan = Channel::::new_outbound(&&feeest, &&keys_provider, node_b_node_id, 10000000, 100000, 42, &config).unwrap(); + + // Create Node B's channel by receiving Node A's open_channel message + // Make sure A's dust limit is as we expect. + let open_channel_msg = node_a_chan.get_open_channel(genesis_block(network).header.block_hash()); + assert_eq!(open_channel_msg.dust_limit_satoshis, 1560); + let node_b_node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[7; 32]).unwrap()); + let node_b_chan = Channel::::new_from_req(&&feeest, &&keys_provider, node_b_node_id, InitFeatures::known(), &open_channel_msg, 7, &config).unwrap(); + + // Node B --> Node A: accept channel, explicitly setting B's dust limit. + let mut accept_channel_msg = node_b_chan.get_accept_channel(); + accept_channel_msg.dust_limit_satoshis = 546; + node_a_chan.accept_channel(&accept_channel_msg, &config, InitFeatures::known()).unwrap(); + + // Put some inbound and outbound HTLCs in A's channel. + let htlc_amount_msat = 11_092_000; // put an amount below A's effective dust limit but above B's. + node_a_chan.pending_inbound_htlcs.push(InboundHTLCOutput { + htlc_id: 0, + amount_msat: htlc_amount_msat, + payment_hash: PaymentHash(Sha256::hash(&[42; 32]).into_inner()), + cltv_expiry: 300000000, + state: InboundHTLCState::Committed, + }); + + node_a_chan.pending_outbound_htlcs.push(OutboundHTLCOutput { + htlc_id: 1, + amount_msat: htlc_amount_msat, // put an amount below A's dust amount but above B's. + payment_hash: PaymentHash(Sha256::hash(&[43; 32]).into_inner()), + cltv_expiry: 200000000, + state: OutboundHTLCState::Committed, + source: HTLCSource::OutboundRoute { + path: Vec::new(), + session_priv: SecretKey::from_slice(&hex::decode("0fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff").unwrap()[..]).unwrap(), + first_hop_htlc_msat: 548, + } + }); + + // 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 = node_a_chan.commit_tx_fee_msat(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 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); + } + + #[test] + fn test_timeout_vs_success_htlc_dust_limit() { + // Make sure that when `next_remote_commit_tx_fee_msat` and `next_local_commit_tx_fee_msat` + // calculate the real dust limits for HTLCs (i.e. the dust limit given by the counterparty + // *plus* the fees paid for the HTLC) they don't swap `HTLC_SUCCESS_TX_WEIGHT` for + // `HTLC_TIMEOUT_TX_WEIGHT`, and vice versa. + let fee_est = TestFeeEstimator{fee_est: 253 }; + let secp_ctx = Secp256k1::new(); + let seed = [42; 32]; + let network = Network::Testnet; + let keys_provider = test_utils::TestKeysInterface::new(&seed, network); + + let node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap()); + let config = UserConfig::default(); + let mut chan = Channel::::new_outbound(&&fee_est, &&keys_provider, node_id, 10000000, 100000, 42, &config).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); + + // 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 / 1000) + chan.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); + 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 / 1000) + chan.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); + assert_eq!(commitment_tx_fee, commitment_tx_fee_0_htlcs); + + chan.channel_transaction_parameters.is_outbound_from_holder = false; + + // 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 / 1000) + chan.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); + 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 / 1000) + chan.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); + assert_eq!(commitment_tx_fee, commitment_tx_fee_1_htlc); + } + #[test] fn channel_reestablish_no_updates() { let feeest = TestFeeEstimator{fee_est: 15000}; diff --git a/lightning/src/ln/functional_tests.rs b/lightning/src/ln/functional_tests.rs index 16212f927..6273604c6 100644 --- a/lightning/src/ln/functional_tests.rs +++ b/lightning/src/ln/functional_tests.rs @@ -1701,8 +1701,9 @@ fn test_fee_spike_violation_fails_htlc() { fn test_chan_reserve_violation_outbound_htlc_inbound_chan() { let mut chanmon_cfgs = create_chanmon_cfgs(2); // Set the fee rate for the channel very high, to the point where the fundee - // sending any amount would result in a channel reserve violation. In this test - // we check that we would be prevented from sending an HTLC in this situation. + // sending any above-dust amount would result in a channel reserve violation. + // In this test we check that we would be prevented from sending an HTLC in + // this situation. chanmon_cfgs[0].fee_estimator = test_utils::TestFeeEstimator { sat_per_kw: 6000 }; chanmon_cfgs[1].fee_estimator = test_utils::TestFeeEstimator { sat_per_kw: 6000 }; let node_cfgs = create_node_cfgs(2, &chanmon_cfgs); @@ -1720,7 +1721,7 @@ fn test_chan_reserve_violation_outbound_htlc_inbound_chan() { }} } - let (route, our_payment_hash, _) = get_route_and_payment_hash!(1000); + let (route, our_payment_hash, _) = get_route_and_payment_hash!(4843000); unwrap_send_err!(nodes[1].node.send_payment(&route, our_payment_hash, &None), true, APIError::ChannelUnavailable { ref err }, assert_eq!(err, "Cannot send value that would put counterparty balance under holder-announced channel reserve value")); assert!(nodes[1].node.get_and_clear_pending_msg_events().is_empty()); @@ -1778,6 +1779,57 @@ fn test_chan_reserve_violation_inbound_htlc_outbound_channel() { check_added_monitors!(nodes[0], 1); } +#[test] +fn test_chan_reserve_dust_inbound_htlcs_outbound_chan() { + // Test that if we receive many dust HTLCs over an outbound channel, they don't count when + // calculating our commitment transaction fee (this was previously broken). + let chanmon_cfgs = create_chanmon_cfgs(2); + let node_cfgs = create_node_cfgs(2, &chanmon_cfgs); + let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None, None]); + let mut nodes = create_network(2, &node_cfgs, &node_chanmgrs); + + // Set nodes[0]'s balance such that they will consider any above-dust received HTLC to be a + // channel reserve violation (so their balance is channel reserve (1000 sats) + commitment + // transaction fee with 0 HTLCs (183 sats)). + create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 100000, 98817000, InitFeatures::known(), InitFeatures::known()); + + let dust_amt = 546000; // Dust amount + // In the previous code, routing this dust payment would cause nodes[0] to perceive a channel + // reserve violation even though it's a dust HTLC and therefore shouldn't count towards the + // commitment transaction fee. + let (_, _) = route_payment(&nodes[1], &[&nodes[0]], dust_amt); +} + +#[test] +fn test_chan_reserve_dust_inbound_htlcs_inbound_chan() { + // Test that if we receive many dust HTLCs over an inbound channel, they don't count when + // calculating our counterparty's commitment transaction fee (this was previously broken). + let chanmon_cfgs = create_chanmon_cfgs(2); + let node_cfgs = create_node_cfgs(2, &chanmon_cfgs); + let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None, None]); + let mut nodes = create_network(2, &node_cfgs, &node_chanmgrs); + create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 100000, 98000000, InitFeatures::known(), InitFeatures::known()); + + let payment_amt = 46000; // Dust amount + // In the previous code, these first four payments would succeed. + let (_, _) = route_payment(&nodes[0], &[&nodes[1]], payment_amt); + let (_, _) = route_payment(&nodes[0], &[&nodes[1]], payment_amt); + let (_, _) = route_payment(&nodes[0], &[&nodes[1]], payment_amt); + let (_, _) = route_payment(&nodes[0], &[&nodes[1]], payment_amt); + + // Then these next 5 would be interpreted by nodes[1] as violating the fee spike buffer. + let (_, _) = route_payment(&nodes[0], &[&nodes[1]], payment_amt); + let (_, _) = route_payment(&nodes[0], &[&nodes[1]], payment_amt); + let (_, _) = route_payment(&nodes[0], &[&nodes[1]], payment_amt); + let (_, _) = route_payment(&nodes[0], &[&nodes[1]], payment_amt); + let (_, _) = route_payment(&nodes[0], &[&nodes[1]], payment_amt); + + // And this last payment previously resulted in nodes[1] closing on its inbound-channel + // counterparty, because it counted all the previous dust HTLCs against nodes[0]'s commitment + // transaction fee and therefore perceived this next payment as a channel reserve violation. + let (_, _) = route_payment(&nodes[0], &[&nodes[1]], payment_amt); +} + #[test] fn test_chan_reserve_violation_inbound_htlc_inbound_chan() { let chanmon_cfgs = create_chanmon_cfgs(3); @@ -2089,23 +2141,6 @@ fn test_channel_reserve_holding_cell_htlcs() { let commit_tx_fee_0_htlcs = 2*commit_tx_fee_msat(feerate, 1); let recv_value_3 = commit_tx_fee_2_htlcs - commit_tx_fee_0_htlcs - total_fee_msat; - { - let (route, our_payment_hash, _) = get_route_and_payment_hash!(recv_value_3 + 1); - let err = nodes[0].node.send_payment(&route, our_payment_hash, &None).err().unwrap(); - match err { - PaymentSendFailure::AllFailedRetrySafe(ref fails) => { - match &fails[0] { - &APIError::ChannelUnavailable{ref err} => - assert!(regex::Regex::new(r"Cannot send value that would put our balance under counterparty-announced channel reserve value \(\d+\)").unwrap().is_match(err)), - _ => panic!("Unexpected error variant"), - } - }, - _ => panic!("Unexpected error variant"), - } - assert!(nodes[0].node.get_and_clear_pending_msg_events().is_empty()); - nodes[0].logger.assert_log_contains("lightning::ln::channelmanager".to_string(), "Cannot send value that would put our balance under counterparty-announced channel reserve value".to_string(), 3); - } - send_payment(&nodes[0], &vec![&nodes[1], &nodes[2]][..], recv_value_3, recv_value_3); let commit_tx_fee_1_htlc = 2*commit_tx_fee_msat(feerate, 1 + 1);