Add HTLCDescriptor::witness_weight

Author: tankyleo

lightning/src/chain/channelmonitor.rs

@@ -3361,6 +3361,7 @@ impl<Signer: ChannelSigner> ChannelMonitorImpl<Signer> {
 					let revokeable_spk = htlcs.first().map(|htlc| self.onchain_tx_handler.signer.get_revokeable_spk(true, htlc.per_commitment_number, &htlc.per_commitment_point, &self.onchain_tx_handler.secp_ctx));
 					for htlc in htlcs {
 						let htlc_spk = self.onchain_tx_handler.signer.get_htlc_spk(&htlc.htlc, true, &htlc.per_commitment_point, &self.onchain_tx_handler.secp_ctx);
+						let witness_weight = self.onchain_tx_handler.signer.get_holder_htlc_transaction_witness_weight(htlc.preimage.is_some());
 						htlc_descriptors.push(HTLCDescriptor {
 							channel_derivation_parameters: ChannelDerivationParameters {
 								keys_id: self.channel_keys_id,
@@ -3376,6 +3377,7 @@ impl<Signer: ChannelSigner> ChannelMonitorImpl<Signer> {
 							counterparty_sig: htlc.counterparty_sig,
 							prev_script_pubkey: htlc_spk,
 							next_script_pubkey: revokeable_spk.clone().unwrap(),
+							witness_weight,
 						});
 					}
 					ret.push(Event::BumpTransaction(BumpTransactionEvent::HTLCResolution {

lightning/src/chain/onchaintx.rs

@@ -1215,6 +1215,7 @@ impl<Signer: ChannelSigner> OnchainTxHandler<Signer> {
 				htlc_idx, preimage, revokeable_spk.clone(),
 			);
 			let htlc_spk = self.signer.get_htlc_spk(&htlc, true, &trusted_tx.per_commitment_point(), &self.secp_ctx);
+			let witness_weight = self.signer.get_holder_htlc_transaction_witness_weight(preimage.is_some());
 
 			let htlc_descriptor = HTLCDescriptor {
 				channel_derivation_parameters: ChannelDerivationParameters {
@@ -1231,6 +1232,7 @@ impl<Signer: ChannelSigner> OnchainTxHandler<Signer> {
 				counterparty_sig: counterparty_htlc_sig.clone(),
 				prev_script_pubkey: htlc_spk,
 				next_script_pubkey: revokeable_spk,
+				witness_weight,
 			};
 			if let Ok(witness) = self.signer.sign_holder_htlc_transaction(&htlc_tx, 0, &htlc_descriptor, &self.secp_ctx) {
 				htlc_tx.input[0].witness = witness;

lightning/src/events/bump_transaction.rs

@@ -725,19 +725,16 @@ where
 		let mut signers_and_revokeable_spks = BTreeMap::new();
 		for htlc_descriptor in htlc_descriptors {
 			// TODO: avoid having mutable references flying around
-			let (_, witness_weight) = signers_and_revokeable_spks.entry(htlc_descriptor.channel_derivation_parameters.keys_id)
+			let _ = signers_and_revokeable_spks.entry(htlc_descriptor.channel_derivation_parameters.keys_id)
 				.or_insert_with(|| {
-					let signer = htlc_descriptor.derive_channel_signer(&self.signer_provider);
-					// TODO: cache this, it does not change throughout the lifetime of the channel
-					let witness_weight = signer.get_holder_htlc_transaction_witness_weight(htlc_descriptor.preimage.is_some());
-					(signer, witness_weight)
+					htlc_descriptor.derive_channel_signer(&self.signer_provider)
 				});
 
 			let htlc_input = htlc_descriptor.unsigned_tx_input();
 			must_spend.push(Input {
 				outpoint: htlc_input.previous_output.clone(),
 				previous_utxo: htlc_descriptor.previous_utxo(),
-				satisfaction_weight: EMPTY_SCRIPT_SIG_WEIGHT + *witness_weight,
+				satisfaction_weight: EMPTY_SCRIPT_SIG_WEIGHT + htlc_descriptor.witness_weight,
 			});
 			htlc_tx.input.push(htlc_input);
 			let htlc_output = htlc_descriptor.tx_output();
@@ -791,7 +788,7 @@ where
 
 		for (idx, htlc_descriptor) in htlc_descriptors.iter().enumerate() {
 			// Unwrap because we derived the corresponding signers for all htlc descriptors further above
-			let signer  = &signers_and_revokeable_spks.get(&htlc_descriptor.channel_derivation_parameters.keys_id).unwrap().0;
+			let signer  = signers_and_revokeable_spks.get(&htlc_descriptor.channel_derivation_parameters.keys_id).unwrap();
 			let witness = signer.sign_holder_htlc_transaction(&htlc_tx, idx, htlc_descriptor, &self.secp)?;
 			htlc_tx.input[idx].witness = witness;
 		}

lightning/src/sign/mod.rs

@@ -580,6 +580,8 @@ pub struct HTLCDescriptor {
 	pub prev_script_pubkey: ScriptBuf,
 	/// Next script pubkey
 	pub next_script_pubkey: ScriptBuf,
+	/// The witness weight
+	pub witness_weight: u64,
 }
 
 impl_writeable_tlv_based!(HTLCDescriptor, {
@@ -593,6 +595,7 @@ impl_writeable_tlv_based!(HTLCDescriptor, {
 	(12, counterparty_sig, required),
 	(14, prev_script_pubkey, required),
 	(16, next_script_pubkey, required),
+	(18, witness_weight, required),
 });
 
 impl HTLCDescriptor {