Store the full event transaction in OnchainEvent structs

When we see a transaction which generates some `OnchainEvent`, its
useful to have the full transaction around for later analysis.
Specifically, it lets us check the list of outputs which were spent
in the transaction, allowing us to look up, e.g. which HTLC
outpoint was spent in a transaction.

This will be used in a few commits to do exactly that - figure out
which HTLC a given `OnchainEvent` corresponds with.

Author: TheBlueMatt

lightning/src/chain/channelmonitor.rs

@@ -315,6 +315,7 @@ struct OnchainEventEntry {
 	txid: Txid,
 	height: u32,
 	event: OnchainEvent,
+	transaction: Option<Transaction>,
 }
 
 impl OnchainEventEntry {
@@ -395,6 +396,7 @@ impl Writeable for OnchainEventEntry {
 	fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 		write_tlv_fields!(writer, {
 			(0, self.txid, required),
+			(1, self.transaction, option),
 			(2, self.height, required),
 			(4, self.event, required),
 		});
@@ -405,15 +407,17 @@ impl Writeable for OnchainEventEntry {
 impl MaybeReadable for OnchainEventEntry {
 	fn read<R: io::Read>(reader: &mut R) -> Result<Option<Self>, DecodeError> {
 		let mut txid = Default::default();
+		let mut transaction = None;
 		let mut height = 0;
 		let mut event = None;
 		read_tlv_fields!(reader, {
 			(0, txid, required),
+			(1, transaction, option),
 			(2, height, required),
 			(4, event, ignorable),
 		});
 		if let Some(ev) = event {
-			Ok(Some(Self { txid, height, event: ev }))
+			Ok(Some(Self { txid, transaction, height, event: ev }))
 		} else {
 			Ok(None)
 		}
@@ -1667,8 +1671,10 @@ impl<Signer: Sign> ChannelMonitor<Signer> {
 /// as long as we examine both the current counterparty commitment transaction and, if it hasn't
 /// been revoked yet, the previous one, we we will never "forget" to resolve an HTLC.
 macro_rules! fail_unbroadcast_htlcs {
-	($self: expr, $commitment_tx_type: expr, $commitment_txid_confirmed: expr,
+	($self: expr, $commitment_tx_type: expr, $commitment_txid_confirmed: expr, $commitment_tx_confirmed: expr,
 	 $commitment_tx_conf_height: expr, $confirmed_htlcs_list: expr, $logger: expr) => { {
+		debug_assert_eq!($commitment_tx_confirmed.txid(), $commitment_txid_confirmed);
+
 		macro_rules! check_htlc_fails {
 			($txid: expr, $commitment_tx: expr) => {
 				if let Some(ref latest_outpoints) = $self.counterparty_claimable_outpoints.get($txid) {
@@ -1708,6 +1714,7 @@ macro_rules! fail_unbroadcast_htlcs {
 							});
 							let entry = OnchainEventEntry {
 								txid: $commitment_txid_confirmed,
+								transaction: Some($commitment_tx_confirmed.clone()),
 								height: $commitment_tx_conf_height,
 								event: OnchainEvent::HTLCUpdate {
 									source: (**source).clone(),
@@ -2136,13 +2143,13 @@ impl<Signer: Sign> ChannelMonitorImpl<Signer> {
 				self.counterparty_commitment_txn_on_chain.insert(commitment_txid, commitment_number);
 
 				if let Some(per_commitment_data) = per_commitment_option {
-					fail_unbroadcast_htlcs!(self, "revoked_counterparty", commitment_txid, height,
+					fail_unbroadcast_htlcs!(self, "revoked_counterparty", commitment_txid, tx, height,
 						per_commitment_data.iter().map(|(htlc, htlc_source)|
 							(htlc, htlc_source.as_ref().map(|htlc_source| htlc_source.as_ref()))
 						), logger);
 				} else {
 					debug_assert!(false, "We should have per-commitment option for any recognized old commitment txn");
-					fail_unbroadcast_htlcs!(self, "revoked counterparty", commitment_txid, height,
+					fail_unbroadcast_htlcs!(self, "revoked counterparty", commitment_txid, tx, height,
 						[].iter().map(|reference| *reference), logger);
 				}
 			}
@@ -2160,7 +2167,7 @@ impl<Signer: Sign> ChannelMonitorImpl<Signer> {
 			self.counterparty_commitment_txn_on_chain.insert(commitment_txid, commitment_number);
 
 			log_info!(logger, "Got broadcast of non-revoked counterparty commitment transaction {}", commitment_txid);
-			fail_unbroadcast_htlcs!(self, "counterparty", commitment_txid, height,
+			fail_unbroadcast_htlcs!(self, "counterparty", commitment_txid, tx, height,
 				per_commitment_data.iter().map(|(htlc, htlc_source)|
 					(htlc, htlc_source.as_ref().map(|htlc_source| htlc_source.as_ref()))
 				), logger);
@@ -2319,7 +2326,7 @@ impl<Signer: Sign> ChannelMonitorImpl<Signer> {
 			let res = self.get_broadcasted_holder_claims(&self.current_holder_commitment_tx, height);
 			let mut to_watch = self.get_broadcasted_holder_watch_outputs(&self.current_holder_commitment_tx, tx);
 			append_onchain_update!(res, to_watch);
-			fail_unbroadcast_htlcs!(self, "latest holder", commitment_txid, height,
+			fail_unbroadcast_htlcs!(self, "latest holder", commitment_txid, tx, height,
 				self.current_holder_commitment_tx.htlc_outputs.iter()
 				.map(|(htlc, _, htlc_source)| (htlc, htlc_source.as_ref())), logger);
 		} else if let &Some(ref holder_tx) = &self.prev_holder_signed_commitment_tx {
@@ -2329,7 +2336,7 @@ impl<Signer: Sign> ChannelMonitorImpl<Signer> {
 				let res = self.get_broadcasted_holder_claims(holder_tx, height);
 				let mut to_watch = self.get_broadcasted_holder_watch_outputs(holder_tx, tx);
 				append_onchain_update!(res, to_watch);
-				fail_unbroadcast_htlcs!(self, "previous holder", commitment_txid, height,
+				fail_unbroadcast_htlcs!(self, "previous holder", commitment_txid, tx, height,
 					holder_tx.htlc_outputs.iter().map(|(htlc, _, htlc_source)| (htlc, htlc_source.as_ref())),
 					logger);
 			}
@@ -2494,6 +2501,7 @@ impl<Signer: Sign> ChannelMonitorImpl<Signer> {
 					let txid = tx.txid();
 					self.onchain_events_awaiting_threshold_conf.push(OnchainEventEntry {
 						txid,
+						transaction: Some((*tx).clone()),
 						height: height,
 						event: OnchainEvent::FundingSpendConfirmation {
 							on_local_output_csv: balance_spendable_csv,
@@ -2911,7 +2919,7 @@ impl<Signer: Sign> ChannelMonitorImpl<Signer> {
 								let outbound_htlc = $holder_tx == htlc_output.offered;
 								if !outbound_htlc || revocation_sig_claim {
 									self.onchain_events_awaiting_threshold_conf.push(OnchainEventEntry {
-										txid: tx.txid(), height,
+										txid: tx.txid(), height, transaction: Some(tx.clone()),
 										event: OnchainEvent::HTLCSpendConfirmation {
 											commitment_tx_output_idx: input.previous_output.vout,
 											preimage: if accepted_preimage_claim || offered_preimage_claim {
@@ -2963,6 +2971,7 @@ impl<Signer: Sign> ChannelMonitorImpl<Signer> {
 						self.onchain_events_awaiting_threshold_conf.push(OnchainEventEntry {
 							txid: tx.txid(),
 							height,
+							transaction: Some(tx.clone()),
 							event: OnchainEvent::HTLCSpendConfirmation {
 								commitment_tx_output_idx: input.previous_output.vout,
 								preimage: Some(payment_preimage),
@@ -2983,6 +2992,7 @@ impl<Signer: Sign> ChannelMonitorImpl<Signer> {
 						} else { false }) {
 						self.onchain_events_awaiting_threshold_conf.push(OnchainEventEntry {
 							txid: tx.txid(),
+							transaction: Some(tx.clone()),
 							height,
 							event: OnchainEvent::HTLCSpendConfirmation {
 								commitment_tx_output_idx: input.previous_output.vout,
@@ -3009,6 +3019,7 @@ impl<Signer: Sign> ChannelMonitorImpl<Signer> {
 					});
 					let entry = OnchainEventEntry {
 						txid: tx.txid(),
+						transaction: Some(tx.clone()),
 						height,
 						event: OnchainEvent::HTLCUpdate {
 							source, payment_hash,
@@ -3082,6 +3093,7 @@ impl<Signer: Sign> ChannelMonitorImpl<Signer> {
 		if let Some(spendable_output) = spendable_output {
 			let entry = OnchainEventEntry {
 				txid: tx.txid(),
+				transaction: Some(tx.clone()),
 				height: height,
 				event: OnchainEvent::MaturingOutput { descriptor: spendable_output.clone() },
 			};