Expose channel_id / counterparty_node_id in BumpTransaction event

A client node might choose not to handle `Event::BumptTransaction`
events and leave bumping / Anchor output spending to a trusted
counterparty.

However, `Event::BumptTransaction` currently doesn't offer any clear
indication what channel and/or counterparty it is referring to. In order
to allow filtering these events, we here expose the `channel_id` and
`counterparty_node_id` fields.

Author: tnull

lightning/src/chain/channelmonitor.rs

@@ -1416,8 +1416,8 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitor<Signer> {
 	/// Loads the funding txo and outputs to watch into the given `chain::Filter` by repeatedly
 	/// calling `chain::Filter::register_output` and `chain::Filter::register_tx` until all outputs
 	/// have been registered.
-	pub fn load_outputs_to_watch<F: Deref, L: Deref>(&self, filter: &F, logger: &L) 
-	where 
+	pub fn load_outputs_to_watch<F: Deref, L: Deref>(&self, filter: &F, logger: &L)
+	where
 		F::Target: chain::Filter, L::Target: Logger,
 	{
 		let lock = self.inner.lock().unwrap();
@@ -2931,12 +2931,19 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
 				ClaimEvent::BumpCommitment {
 					package_target_feerate_sat_per_1000_weight, commitment_tx, anchor_output_idx,
 				} => {
+					let channel_id = self.channel_id;
+					// unwrap safety: `ClaimEvent`s are only available for Anchor channels,
+					// introduced with v0.0.116. counterparty_node_id is guaranteed to be `Some`
+					// since v0.0.110.
+					let counterparty_node_id = self.counterparty_node_id.unwrap();
 					let commitment_txid = commitment_tx.txid();
 					debug_assert_eq!(self.current_holder_commitment_tx.txid, commitment_txid);
 					let pending_htlcs = self.current_holder_commitment_tx.non_dust_htlcs();
 					let commitment_tx_fee_satoshis = self.channel_value_satoshis -
 						commitment_tx.output.iter().fold(0u64, |sum, output| sum + output.value);
 					ret.push(Event::BumpTransaction(BumpTransactionEvent::ChannelClose {
+						channel_id,
+						counterparty_node_id,
 						claim_id,
 						package_target_feerate_sat_per_1000_weight,
 						commitment_tx,
@@ -2958,6 +2965,11 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
 				ClaimEvent::BumpHTLC {
 					target_feerate_sat_per_1000_weight, htlcs, tx_lock_time,
 				} => {
+					let channel_id = self.channel_id;
+					// unwrap safety: `ClaimEvent`s are only available for Anchor channels,
+					// introduced with v0.0.116. counterparty_node_id is guaranteed to be `Some`
+					// since v0.0.110.
+					let counterparty_node_id = self.counterparty_node_id.unwrap();
 					let mut htlc_descriptors = Vec::with_capacity(htlcs.len());
 					for htlc in htlcs {
 						htlc_descriptors.push(HTLCDescriptor {
@@ -2978,6 +2990,8 @@ impl<Signer: WriteableEcdsaChannelSigner> ChannelMonitorImpl<Signer> {
 						});
 					}
 					ret.push(Event::BumpTransaction(BumpTransactionEvent::HTLCResolution {
+						channel_id,
+						counterparty_node_id,
 						claim_id,
 						target_feerate_sat_per_1000_weight,
 						htlc_descriptors,

lightning/src/events/bump_transaction.rs

@@ -18,6 +18,7 @@ use crate::chain::chaininterface::{BroadcasterInterface, fee_for_weight};
 use crate::chain::ClaimId;
 use crate::io_extras::sink;
 use crate::ln::channel::ANCHOR_OUTPUT_VALUE_SATOSHI;
+use crate::ln::ChannelId;
 use crate::ln::chan_utils;
 use crate::ln::chan_utils::{
 	ANCHOR_INPUT_WITNESS_WEIGHT, HTLC_SUCCESS_INPUT_ANCHOR_WITNESS_WEIGHT,
@@ -37,7 +38,7 @@ use bitcoin::blockdata::locktime::absolute::LockTime;
 use bitcoin::consensus::Encodable;
 use bitcoin::psbt::PartiallySignedTransaction;
 use bitcoin::secp256k1;
-use bitcoin::secp256k1::Secp256k1;
+use bitcoin::secp256k1::{PublicKey, Secp256k1};
 use bitcoin::secp256k1::ecdsa::Signature;
 
 const EMPTY_SCRIPT_SIG_WEIGHT: u64 = 1 /* empty script_sig */ * WITNESS_SCALE_FACTOR as u64;
@@ -147,6 +148,10 @@ pub enum BumpTransactionEvent {
 	/// [`EcdsaChannelSigner::sign_holder_anchor_input`]: crate::sign::ecdsa::EcdsaChannelSigner::sign_holder_anchor_input
 	/// [`build_anchor_input_witness`]: crate::ln::chan_utils::build_anchor_input_witness
 	ChannelClose {
+		/// The `channel_id` of the channel which has been closed.
+		channel_id: ChannelId,
+		/// Counterparty in the closed channel.
+		counterparty_node_id: PublicKey,
 		/// The unique identifier for the claim of the anchor output in the commitment transaction.
 		///
 		/// The identifier must map to the set of external UTXOs assigned to the claim, such that
@@ -200,6 +205,10 @@ pub enum BumpTransactionEvent {
 	/// [`EcdsaChannelSigner`]: crate::sign::ecdsa::EcdsaChannelSigner
 	/// [`EcdsaChannelSigner::sign_holder_htlc_transaction`]: crate::sign::ecdsa::EcdsaChannelSigner::sign_holder_htlc_transaction
 	HTLCResolution {
+		/// The `channel_id` of the channel which has been closed.
+		channel_id: ChannelId,
+		/// Counterparty in the closed channel.
+		counterparty_node_id: PublicKey,
 		/// The unique identifier for the claim of the HTLCs in the confirmed commitment
 		/// transaction.
 		///
@@ -797,7 +806,7 @@ where
 				}
 			}
 			BumpTransactionEvent::HTLCResolution {
-				claim_id, target_feerate_sat_per_1000_weight, htlc_descriptors, tx_lock_time,
+				claim_id, target_feerate_sat_per_1000_weight, htlc_descriptors, tx_lock_time, ..
 			} => {
 				log_info!(self.logger, "Handling HTLC bump (claim_id = {}, htlcs_to_claim = {})",
 					log_bytes!(claim_id.0), log_iter!(htlc_descriptors.iter().map(|d| d.outpoint())));