Cache remote HTLC inside OnchainTxHandler::RemoteTxCache

As we can't predict if any and which revoked commitment tx is
going to appear onchain we have by design to cache all htlc information
to regenerate htlc script if needed.

diff --git a/lightning/src/ln/channelmonitor.rs b/lightning/src/ln/channelmonitor.rs
index 6f00392c214c67002e08110930e945976ca342d9..19db34a700b2b2926c8768c653cc93f6ab4a5fcd 100644 (file)
--- a/lightning/src/ln/channelmonitor.rs
+++ b/lightning/src/ln/channelmonitor.rs
@@ -1193,7 +1193,7 @@ impl<ChanSigner: ChannelKeys> ChannelMonitor<ChanSigner> {
                log_trace!(logger, "New potential remote commitment transaction: {}", encode::serialize_hex(unsigned_commitment_tx));
                self.prev_remote_commitment_txid = self.current_remote_commitment_txid.take();
                self.current_remote_commitment_txid = Some(new_txid);
-               self.remote_claimable_outpoints.insert(new_txid, htlc_outputs);
+               self.remote_claimable_outpoints.insert(new_txid, htlc_outputs.clone());
                self.current_remote_commitment_number = commitment_number;
                //TODO: Merge this into the other per-remote-transaction output storage stuff
                match self.their_cur_revocation_points {
@@ -1214,6 +1214,13 @@ impl<ChanSigner: ChannelKeys> ChannelMonitor<ChanSigner> {
                                self.their_cur_revocation_points = Some((commitment_number, their_revocation_point, None));
                        }
                }
+               let mut htlcs = Vec::with_capacity(htlc_outputs.len());
+               for htlc in htlc_outputs {
+                       if htlc.0.transaction_output_index.is_some() {
+                               htlcs.push(htlc.0);
+                       }
+               }
+               self.onchain_tx_handler.provide_latest_remote_tx(new_txid, htlcs);
        }
 
        /// Informs this monitor of the latest local (ie broadcastable) commitment transaction. The

diff --git a/lightning/src/ln/onchaintx.rs b/lightning/src/ln/onchaintx.rs
index eb30f155cfe3c683fa424fb0c0cce266bfc94aae..7e84132e481b3c11799d4b6e8f27c0f281bb8a20 100644 (file)
--- a/lightning/src/ln/onchaintx.rs
+++ b/lightning/src/ln/onchaintx.rs
@@ -17,7 +17,7 @@ use bitcoin::secp256k1::key::PublicKey;
 use ln::msgs::DecodeError;
 use ln::channelmonitor::{ANTI_REORG_DELAY, CLTV_SHARED_CLAIM_BUFFER, InputMaterial, ClaimRequest};
 use ln::channelmanager::PaymentPreimage;
-use ln::chan_utils::{HTLCType, LocalCommitmentTransaction};
+use ln::chan_utils::{HTLCType, LocalCommitmentTransaction, HTLCOutputInCommitment};
 use chain::chaininterface::{FeeEstimator, BroadcasterInterface, ConfirmationTarget, MIN_RELAY_FEE_SAT_PER_1000_WEIGHT};
 use chain::keysinterface::ChannelKeys;
 use util::logger::Logger;
@@ -52,7 +52,8 @@ enum OnchainEvent {
 /// remote outputs, either justice or preimage/timeout transactions.
 struct RemoteTxCache {
        remote_delayed_payment_base_key: PublicKey,
-       remote_htlc_base_key: PublicKey
+       remote_htlc_base_key: PublicKey,
+       per_htlc: HashMap<Sha256dHash, Vec<(HTLCOutputInCommitment)>>
 }
 
 /// Higher-level cache structure needed to re-generate bumped claim txn if needed
@@ -251,6 +252,14 @@ impl<ChanSigner: ChannelKeys + Writeable> OnchainTxHandler<ChanSigner> {
 
                self.remote_tx_cache.remote_delayed_payment_base_key.write(writer)?;
                self.remote_tx_cache.remote_htlc_base_key.write(writer)?;
+               writer.write_all(&byte_utils::be64_to_array(self.remote_tx_cache.per_htlc.len() as u64))?;
+               for (ref txid, ref htlcs) in self.remote_tx_cache.per_htlc.iter() {
+                       writer.write_all(&txid[..])?;
+                       writer.write_all(&byte_utils::be64_to_array(htlcs.len() as u64))?;
+                       for &ref htlc in htlcs.iter() {
+                               htlc.write(writer)?;
+                       }
+               }
                self.remote_csv.write(writer)?;
 
                self.key_storage.write(writer)?;
@@ -304,9 +313,24 @@ impl<ChanSigner: ChannelKeys + Readable> Readable for OnchainTxHandler<ChanSigne
                let remote_tx_cache = {
                        let remote_delayed_payment_base_key = Readable::read(reader)?;
                        let remote_htlc_base_key = Readable::read(reader)?;
+                       let per_htlc_len: u64 = Readable::read(reader)?;
+                       let mut per_htlc = HashMap::with_capacity(cmp::min(per_htlc_len as usize, MAX_ALLOC_SIZE / 64));
+                       for _  in 0..per_htlc_len {
+                               let txid: Sha256dHash = Readable::read(reader)?;
+                               let htlcs_count: u64 = Readable::read(reader)?;
+                               let mut htlcs = Vec::with_capacity(cmp::min(htlcs_count as usize, MAX_ALLOC_SIZE / 32));
+                               for _ in 0..htlcs_count {
+                                       let htlc = Readable::read(reader)?;
+                                       htlcs.push(htlc);
+                               }
+                               if let Some(_) = per_htlc.insert(txid, htlcs) {
+                                       return Err(DecodeError::InvalidValue);
+                               }
+                       }
                        RemoteTxCache {
                                remote_delayed_payment_base_key,
                                remote_htlc_base_key,
+                               per_htlc,
                        }
                };
                let remote_csv = Readable::read(reader)?;
@@ -382,6 +406,7 @@ impl<ChanSigner: ChannelKeys> OnchainTxHandler<ChanSigner> {
                let remote_tx_cache = RemoteTxCache {
                        remote_delayed_payment_base_key,
                        remote_htlc_base_key,
+                       per_htlc: HashMap::new(),
                };
 
                OnchainTxHandler {
@@ -902,6 +927,10 @@ impl<ChanSigner: ChannelKeys> OnchainTxHandler<ChanSigner> {
                }
        }
 
+       pub(super) fn provide_latest_remote_tx(&mut self, commitment_txid: Sha256dHash, htlcs: Vec<HTLCOutputInCommitment>) {
+               self.remote_tx_cache.per_htlc.insert(commitment_txid, htlcs);
+       }
+
        #[cfg(test)]
        pub(super) fn get_fully_signed_copy_local_tx(&mut self, funding_redeemscript: &Script) -> Option<Transaction> {
                if let Some(ref mut local_commitment) = self.local_commitment {