From 3e149b1fb6624eef99b055bde772842f364abdca Mon Sep 17 00:00:00 2001 From: Antoine Riard Date: Tue, 11 Sep 2018 01:40:53 +0000 Subject: [PATCH] Implement claiming of revoked HTLC transactions by ChannelMonitor Refactor check_spend_remote_transaction in part to check_spend_remote_htlc to avoid lock mess in block_connected. We need remote_commitment_txn_on_chain to match remote HTLC tx --- src/ln/channelmonitor.rs | 104 ++++++++++++++++++++++++++++++++++++--- 1 file changed, 97 insertions(+), 7 deletions(-) diff --git a/src/ln/channelmonitor.rs b/src/ln/channelmonitor.rs index 81efedcbf..6de0a6360 100644 --- a/src/ln/channelmonitor.rs +++ b/src/ln/channelmonitor.rs @@ -924,8 +924,7 @@ impl ChannelMonitor { /// Attempts to claim a remote commitment transaction's outputs using the revocation key and /// data in remote_claimable_outpoints. Will directly claim any HTLC outputs which expire at a /// height > height + CLTV_SHARED_CLAIM_BUFFER. In any case, will install monitoring for - /// HTLC-Success/HTLC-Timeout transactions, and claim them using the revocation key (if - /// applicable) as well. + /// HTLC-Success/HTLC-Timeout transactions. fn check_spend_remote_transaction(&self, tx: &Transaction, height: u32) -> (Vec, (Sha256dHash, Vec)) { // Most secp and related errors trying to create keys means we have no hope of constructing // a spend transaction...so we return no transactions to broadcast @@ -1205,13 +1204,97 @@ impl ChannelMonitor { txn_to_broadcast.push(spend_tx); } } - } else { - //TODO: For each input check if its in our remote_commitment_txn_on_chain map! } (txn_to_broadcast, (commitment_txid, watch_outputs)) } + /// Attempst to claim a remote HTLC-Success/HTLC-Timeout s outputs using the revocation key + fn check_spend_remote_htlc(&self, tx: &Transaction, commitment_number: u64) -> Vec { + let mut txn_to_broadcast = Vec::new(); + + let htlc_txid = tx.txid(); //TODO: This is gonna be a performance bottleneck for watchtowers! + + macro_rules! ignore_error { + ( $thing : expr ) => { + match $thing { + Ok(a) => a, + Err(_) => return txn_to_broadcast + } + }; + } + + let secret = self.get_secret(commitment_number).unwrap(); + let per_commitment_key = ignore_error!(SecretKey::from_slice(&self.secp_ctx, &secret)); + let revocation_pubkey = match self.key_storage { + KeyStorage::PrivMode { ref revocation_base_key, .. } => { + let per_commitment_point = PublicKey::from_secret_key(&self.secp_ctx, &per_commitment_key); + ignore_error!(chan_utils::derive_public_revocation_key(&self.secp_ctx, &per_commitment_point, &PublicKey::from_secret_key(&self.secp_ctx, &revocation_base_key))) + }, + KeyStorage::SigsMode { ref revocation_base_key, .. } => { + let per_commitment_point = PublicKey::from_secret_key(&self.secp_ctx, &per_commitment_key); + ignore_error!(chan_utils::derive_public_revocation_key(&self.secp_ctx, &per_commitment_point, &revocation_base_key)) + }, + }; + let delayed_key = match self.their_delayed_payment_base_key { + None => return txn_to_broadcast, + Some(their_delayed_payment_base_key) => ignore_error!(chan_utils::derive_public_key(&self.secp_ctx, &PublicKey::from_secret_key(&self.secp_ctx, &per_commitment_key), &their_delayed_payment_base_key)), + }; + let redeemscript = chan_utils::get_revokeable_redeemscript(&revocation_pubkey, self.their_to_self_delay.unwrap(), &delayed_key); + let revokeable_p2wsh = redeemscript.to_v0_p2wsh(); + + let mut inputs = Vec::new(); + let mut amount = 0; + + if tx.output[0].script_pubkey == revokeable_p2wsh { //HTLC transactions have one txin, one txout + inputs.push(TxIn { + previous_output: BitcoinOutPoint { + txid: htlc_txid, + vout: 0, + }, + script_sig: Script::new(), + sequence: 0xfffffffd, + witness: Vec::new(), + }); + amount = tx.output[0].value; + } + + if !inputs.is_empty() { + let outputs = vec!(TxOut { + script_pubkey: self.destination_script.clone(), + value: amount, //TODO: - fee + }); + + let mut spend_tx = Transaction { + version: 2, + lock_time: 0, + input: inputs, + output: outputs, + }; + + + let sighash_parts = bip143::SighashComponents::new(&spend_tx); + + let sig = match self.key_storage { + KeyStorage::PrivMode { ref revocation_base_key, .. } => { + let sighash = ignore_error!(Message::from_slice(&sighash_parts.sighash_all(&spend_tx.input[0], &redeemscript, amount)[..])); + let revocation_key = ignore_error!(chan_utils::derive_private_revocation_key(&self.secp_ctx, &per_commitment_key, &revocation_base_key)); + self.secp_ctx.sign(&sighash, &revocation_key) + } + KeyStorage::SigsMode { .. } => { + unimplemented!(); + } + }; + spend_tx.input[0].witness.push(sig.serialize_der(&self.secp_ctx).to_vec()); + spend_tx.input[0].witness[0].push(SigHashType::All as u8); + spend_tx.input[0].witness.push(vec!(1)); + spend_tx.input[0].witness.push(redeemscript.into_bytes()); + + txn_to_broadcast.push(spend_tx); + } + txn_to_broadcast + } + fn broadcast_by_local_state(&self, local_tx: &LocalSignedTx) -> Vec { let mut res = Vec::with_capacity(local_tx.htlc_outputs.len()); @@ -1273,19 +1356,26 @@ impl ChannelMonitor { fn block_connected(&self, txn_matched: &[&Transaction], height: u32, broadcaster: &BroadcasterInterface)-> Vec<(Sha256dHash, Vec)> { let mut watch_outputs = Vec::new(); for tx in txn_matched { + let mut txn: Vec = Vec::new(); for txin in tx.input.iter() { if self.funding_txo.is_none() || (txin.previous_output.txid == self.funding_txo.as_ref().unwrap().0.txid && txin.previous_output.vout == self.funding_txo.as_ref().unwrap().0.index as u32) { - let (mut txn, new_outputs) = self.check_spend_remote_transaction(tx, height); + let (remote_txn, new_outputs) = self.check_spend_remote_transaction(tx, height); + txn = remote_txn; if !new_outputs.1.is_empty() { watch_outputs.push(new_outputs); } if txn.is_empty() { txn = self.check_spend_local_transaction(tx, height); } - for tx in txn.iter() { - broadcaster.broadcast_transaction(tx); + } else { + let remote_commitment_txn_on_chain = self.remote_commitment_txn_on_chain.lock().unwrap(); + for commitment_number in remote_commitment_txn_on_chain.get(&txin.previous_output.txid) { + txn = self.check_spend_remote_htlc(tx, *commitment_number); } } + for tx in txn.iter() { + broadcaster.broadcast_transaction(tx); + } } } if let Some(ref cur_local_tx) = self.current_local_signed_commitment_tx { -- 2.39.5