Watch outputs of revoked HTLC-transactions

[rust-lightning] / lightning / src / ln / channelmonitor.rs

diff --git a/lightning/src/ln/channelmonitor.rs b/lightning/src/ln/channelmonitor.rs
index c1452457202305cdee05d2cad2825a7ecb2df36c..514a95d27db9339edc8b78989a0477695ae102ab 100644 (file)
--- a/lightning/src/ln/channelmonitor.rs
+++ b/lightning/src/ln/channelmonitor.rs
@@ -1668,22 +1668,22 @@ impl<ChanSigner: ChannelKeys> ChannelMonitor<ChanSigner> {
        }
 
        /// Attempts to claim a remote HTLC-Success/HTLC-Timeout's outputs using the revocation key
-       fn check_spend_remote_htlc(&mut self, tx: &Transaction, commitment_number: u64, height: u32) -> Vec<ClaimRequest> {
-               //TODO: send back new outputs to guarantee pending_claim_request consistency
+       fn check_spend_remote_htlc(&mut self, tx: &Transaction, commitment_number: u64, height: u32) -> (Vec<ClaimRequest>, Option<(Sha256dHash, Vec<TxOut>)>) {
+               let htlc_txid = tx.txid();
                if tx.input.len() != 1 || tx.output.len() != 1 || tx.input[0].witness.len() != 5 {
-                       return Vec::new()
+                       return (Vec::new(), None)
                }
 
                macro_rules! ignore_error {
                        ( $thing : expr ) => {
                                match $thing {
                                        Ok(a) => a,
-                                       Err(_) => return Vec::new()
+                                       Err(_) => return (Vec::new(), None)
                                }
                        };
                }
 
-               let secret = if let Some(secret) = self.get_secret(commitment_number) { secret } else { return Vec::new(); };
+               let secret = if let Some(secret) = self.get_secret(commitment_number) { secret } else { return (Vec::new(), None); };
                let per_commitment_key = ignore_error!(SecretKey::from_slice(&secret));
                let per_commitment_point = PublicKey::from_secret_key(&self.secp_ctx, &per_commitment_key);
                let (revocation_pubkey, revocation_key) = match self.key_storage {
@@ -1694,16 +1694,15 @@ impl<ChanSigner: ChannelKeys> ChannelMonitor<ChanSigner> {
                        Storage::Watchtower { .. } => { unimplemented!() }
                };
                let delayed_key = match self.their_delayed_payment_base_key {
-                       None => return Vec::new(),
+                       None => return (Vec::new(), None),
                        Some(their_delayed_payment_base_key) => ignore_error!(chan_utils::derive_public_key(&self.secp_ctx, &per_commitment_point, &their_delayed_payment_base_key)),
                };
                let redeemscript = chan_utils::get_revokeable_redeemscript(&revocation_pubkey, self.our_to_self_delay, &delayed_key);
-               let htlc_txid = tx.txid(); //TODO: This is gonna be a performance bottleneck for watchtowers!
 
                log_trace!(self, "Remote HTLC broadcast {}:{}", htlc_txid, 0);
                let witness_data = InputMaterial::Revoked { witness_script: redeemscript, pubkey: Some(revocation_pubkey), key: revocation_key, is_htlc: false, amount: tx.output[0].value };
                let claimable_outpoints = vec!(ClaimRequest { absolute_timelock: height + self.our_to_self_delay as u32, aggregable: true, outpoint: BitcoinOutPoint { txid: htlc_txid, vout: 0}, witness_data });
-               claimable_outpoints
+               (claimable_outpoints, Some((htlc_txid, tx.output.clone())))
        }
 
        fn broadcast_by_local_state(&self, local_tx: &LocalSignedTx, delayed_payment_base_key: &SecretKey) -> (Vec<Transaction>, Vec<SpendableOutputDescriptor>, Vec<TxOut>) {
@@ -2019,8 +2018,11 @@ impl<ChanSigner: ChannelKeys> ChannelMonitor<ChanSigner> {
                                        }
                                } else {
                                        if let Some(&(commitment_number, _)) = self.remote_commitment_txn_on_chain.get(&prevout.txid) {
-                                               let mut new_outpoints = self.check_spend_remote_htlc(&tx, commitment_number, height);
+                                               let (mut new_outpoints, new_outputs_option) = self.check_spend_remote_htlc(&tx, commitment_number, height);
                                                claimable_outpoints.append(&mut new_outpoints);
+                                               if let Some(new_outputs) = new_outputs_option {
+                                                       watch_outputs.push(new_outputs);
+                                               }
                                        }
                                }
                        }