From 1079753f20a7baf045164686a79f1fbcf44650aa Mon Sep 17 00:00:00 2001 From: Valentine Wallace Date: Fri, 5 Feb 2021 13:09:23 -0500 Subject: [PATCH] Ensure build_commitment_tx and next_local/remote_tx_fee agree on the fee --- lightning/src/ln/channel.rs | 133 ++++++++++++++++++++++++++++++++++-- 1 file changed, 129 insertions(+), 4 deletions(-) diff --git a/lightning/src/ln/channel.rs b/lightning/src/ln/channel.rs index 316c6721b..d3a372e47 100644 --- a/lightning/src/ln/channel.rs +++ b/lightning/src/ln/channel.rs @@ -42,6 +42,8 @@ use std; use std::default::Default; use std::{cmp,mem,fmt}; use std::ops::Deref; +#[cfg(any(test, feature = "fuzztarget"))] +use std::sync::Mutex; use bitcoin::hashes::hex::ToHex; #[cfg(test)] @@ -407,6 +409,24 @@ pub(super) struct Channel { commitment_secrets: CounterpartyCommitmentSecrets, network_sync: UpdateStatus, + + // We save these values so we can make sure `next_local_commit_tx_fee_msat` and + // `next_remote_commit_tx_fee_msat` properly predict what the next commitment transaction fee will + // be, by comparing the cached values to the fee of the tranaction generated by + // `build_commitment_transaction`. + #[cfg(any(test, feature = "fuzztarget"))] + next_local_commitment_tx_fee_info_cached: Mutex>, + #[cfg(any(test, feature = "fuzztarget"))] + next_remote_commitment_tx_fee_info_cached: Mutex>, +} + +#[cfg(any(test, feature = "fuzztarget"))] +struct CommitmentTxInfoCached { + fee: u64, + total_pending_htlcs: usize, + next_holder_htlc_id: u64, + next_counterparty_htlc_id: u64, + feerate: u32, } pub const OUR_MAX_HTLCS: u16 = 50; //TODO @@ -578,6 +598,11 @@ impl Channel { commitment_secrets: CounterpartyCommitmentSecrets::new(), network_sync: UpdateStatus::Fresh, + + #[cfg(any(test, feature = "fuzztarget"))] + next_local_commitment_tx_fee_info_cached: Mutex::new(None), + #[cfg(any(test, feature = "fuzztarget"))] + next_remote_commitment_tx_fee_info_cached: Mutex::new(None), }) } @@ -811,6 +836,11 @@ impl Channel { commitment_secrets: CounterpartyCommitmentSecrets::new(), network_sync: UpdateStatus::Fresh, + + #[cfg(any(test, feature = "fuzztarget"))] + next_local_commitment_tx_fee_info_cached: Mutex::new(None), + #[cfg(any(test, feature = "fuzztarget"))] + next_remote_commitment_tx_fee_info_cached: Mutex::new(None), }; Ok(chan) @@ -1768,7 +1798,32 @@ impl Channel { } } - self.commit_tx_fee_msat(included_htlcs + addl_htlcs) + let num_htlcs = included_htlcs + addl_htlcs; + let res = self.commit_tx_fee_msat(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); + } + let total_pending_htlcs = self.pending_inbound_htlcs.len() + self.pending_outbound_htlcs.len() + + self.holding_cell_htlc_updates.len(); + let commitment_tx_info = CommitmentTxInfoCached { + fee, + total_pending_htlcs, + next_holder_htlc_id: match htlc.origin { + HTLCInitiator::LocalOffered => self.next_holder_htlc_id + 1, + HTLCInitiator::RemoteOffered => self.next_holder_htlc_id, + }, + next_counterparty_htlc_id: match htlc.origin { + HTLCInitiator::LocalOffered => self.next_counterparty_htlc_id, + HTLCInitiator::RemoteOffered => self.next_counterparty_htlc_id + 1, + }, + feerate: self.feerate_per_kw, + }; + *self.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 @@ -1816,11 +1871,36 @@ impl Channel { match htlc.state { OutboundHTLCState::Committed => included_htlcs += 1, OutboundHTLCState::RemoteRemoved {..} => included_htlcs += 1, + OutboundHTLCState::LocalAnnounced { .. } => included_htlcs += 1, _ => {}, } } - self.commit_tx_fee_msat(included_htlcs + addl_htlcs) + let num_htlcs = included_htlcs + addl_htlcs; + let res = self.commit_tx_fee_msat(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); + } + let total_pending_htlcs = self.pending_inbound_htlcs.len() + self.pending_outbound_htlcs.len(); + let commitment_tx_info = CommitmentTxInfoCached { + fee, + total_pending_htlcs, + next_holder_htlc_id: match htlc.origin { + HTLCInitiator::LocalOffered => self.next_holder_htlc_id + 1, + HTLCInitiator::RemoteOffered => self.next_holder_htlc_id, + }, + next_counterparty_htlc_id: match htlc.origin { + HTLCInitiator::LocalOffered => self.next_counterparty_htlc_id, + HTLCInitiator::RemoteOffered => self.next_counterparty_htlc_id + 1, + }, + feerate: self.feerate_per_kw, + }; + *self.next_remote_commitment_tx_fee_info_cached.lock().unwrap() = Some(commitment_tx_info); + } + res } pub fn update_add_htlc(&mut self, msg: &msgs::UpdateAddHTLC, mut pending_forward_status: PendingHTLCStatus, create_pending_htlc_status: F, logger: &L) -> Result<(), ChannelError> @@ -2057,15 +2137,31 @@ impl Channel { (commitment_tx.1, htlcs_cloned, commitment_tx.0, commitment_txid) }; + let total_fee = feerate_per_kw as u64 * (COMMITMENT_TX_BASE_WEIGHT + (num_htlcs as u64) * COMMITMENT_TX_WEIGHT_PER_HTLC) / 1000; //If channel fee was updated by funder confirm funder can afford the new fee rate when applied to the current local commitment transaction if update_fee { - let total_fee = feerate_per_kw as u64 * (COMMITMENT_TX_BASE_WEIGHT + (num_htlcs as u64) * COMMITMENT_TX_WEIGHT_PER_HTLC) / 1000; - let counterparty_reserve_we_require = Channel::::get_holder_selected_channel_reserve_satoshis(self.channel_value_satoshis); if self.channel_value_satoshis - self.value_to_self_msat / 1000 < total_fee + counterparty_reserve_we_require { return Err((None, ChannelError::Close("Funding remote cannot afford proposed new fee".to_owned()))); } } + #[cfg(any(test, feature = "fuzztarget"))] + { + if self.is_outbound() { + let projected_commit_tx_info = self.next_local_commitment_tx_fee_info_cached.lock().unwrap().take(); + *self.next_remote_commitment_tx_fee_info_cached.lock().unwrap() = None; + if let Some(info) = projected_commit_tx_info { + let total_pending_htlcs = self.pending_inbound_htlcs.len() + self.pending_outbound_htlcs.len() + + self.holding_cell_htlc_updates.len(); + if info.total_pending_htlcs == total_pending_htlcs + && 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, 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)))); @@ -2331,6 +2427,12 @@ impl Channel { return Err(ChannelError::Close("Received an unexpected revoke_and_ack".to_owned())); } + #[cfg(any(test, feature = "fuzztarget"))] + { + *self.next_local_commitment_tx_fee_info_cached.lock().unwrap() = None; + *self.next_remote_commitment_tx_fee_info_cached.lock().unwrap() = None; + } + self.commitment_secrets.provide_secret(self.cur_counterparty_commitment_transaction_number + 1, msg.per_commitment_secret) .map_err(|_| ChannelError::Close("Previous secrets did not match new one".to_owned()))?; self.latest_monitor_update_id += 1; @@ -3961,6 +4063,24 @@ impl Channel { let counterparty_commitment_txid = counterparty_commitment_tx.0.trust().txid(); let (signature, htlc_signatures); + #[cfg(any(test, feature = "fuzztarget"))] + { + if !self.is_outbound() { + let projected_commit_tx_info = self.next_remote_commitment_tx_fee_info_cached.lock().unwrap().take(); + *self.next_local_commitment_tx_fee_info_cached.lock().unwrap() = None; + if let Some(info) = projected_commit_tx_info { + let total_pending_htlcs = self.pending_inbound_htlcs.len() + self.pending_outbound_htlcs.len(); + if info.total_pending_htlcs == total_pending_htlcs + && 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.1); + assert_eq!(actual_fee, info.fee); + } + } + } + } + { let mut htlcs = Vec::with_capacity(counterparty_commitment_tx.2.len()); for &(ref htlc, _) in counterparty_commitment_tx.2.iter() { @@ -4551,6 +4671,11 @@ impl<'a, ChanSigner: ChannelKeys, K: Deref> ReadableArgs<&'a K> for Channel