Pass monitor updates by reference, not owned

In the next commit(s) we'll start holding `ChannelMonitorUpdate`s
that are being persisted in `Channel`s until they're done
persisting. In order to do that, switch to applying the updates by
reference instead of value.

Author: TheBlueMatt

fuzz/src/chanmon_consistency.rs

@@ -152,15 +152,15 @@ impl chain::Watch<EnforcingSigner> for TestChainMonitor {
 		self.chain_monitor.watch_channel(funding_txo, monitor)
 	}
 
-	fn update_channel(&self, funding_txo: OutPoint, update: channelmonitor::ChannelMonitorUpdate) -> chain::ChannelMonitorUpdateStatus {
+	fn update_channel(&self, funding_txo: OutPoint, update: &channelmonitor::ChannelMonitorUpdate) -> chain::ChannelMonitorUpdateStatus {
 		let mut map_lock = self.latest_monitors.lock().unwrap();
 		let mut map_entry = match map_lock.entry(funding_txo) {
 			hash_map::Entry::Occupied(entry) => entry,
 			hash_map::Entry::Vacant(_) => panic!("Didn't have monitor on update call"),
 		};
 		let deserialized_monitor = <(BlockHash, channelmonitor::ChannelMonitor<EnforcingSigner>)>::
 			read(&mut Cursor::new(&map_entry.get().1), (&*self.keys, &*self.keys)).unwrap().1;
-		deserialized_monitor.update_monitor(&update, &&TestBroadcaster{}, &FuzzEstimator { ret_val: atomic::AtomicU32::new(253) }, &self.logger).unwrap();
+		deserialized_monitor.update_monitor(update, &&TestBroadcaster{}, &FuzzEstimator { ret_val: atomic::AtomicU32::new(253) }, &self.logger).unwrap();
 		let mut ser = VecWriter(Vec::new());
 		deserialized_monitor.write(&mut ser).unwrap();
 		map_entry.insert((update.update_id, ser.0));

fuzz/src/utils/test_persister.rs

@@ -14,7 +14,7 @@ impl chainmonitor::Persist<EnforcingSigner> for TestPersister {
 		self.update_ret.lock().unwrap().clone()
 	}
 
-	fn update_persisted_channel(&self, _funding_txo: OutPoint, _update: &Option<channelmonitor::ChannelMonitorUpdate>, _data: &channelmonitor::ChannelMonitor<EnforcingSigner>, _update_id: MonitorUpdateId) -> chain::ChannelMonitorUpdateStatus {
+	fn update_persisted_channel(&self, _funding_txo: OutPoint, _update: Option<&channelmonitor::ChannelMonitorUpdate>, _data: &channelmonitor::ChannelMonitor<EnforcingSigner>, _update_id: MonitorUpdateId) -> chain::ChannelMonitorUpdateStatus {
 		self.update_ret.lock().unwrap().clone()
 	}
 }

lightning/src/chain/chainmonitor.rs

@@ -144,7 +144,7 @@ pub trait Persist<ChannelSigner: Sign> {
 	/// [`ChannelMonitorUpdateStatus`] for requirements when returning errors.
 	///
 	/// [`Writeable::write`]: crate::util::ser::Writeable::write
-	fn update_persisted_channel(&self, channel_id: OutPoint, update: &Option<ChannelMonitorUpdate>, data: &ChannelMonitor<ChannelSigner>, update_id: MonitorUpdateId) -> ChannelMonitorUpdateStatus;
+	fn update_persisted_channel(&self, channel_id: OutPoint, update: Option<&ChannelMonitorUpdate>, data: &ChannelMonitor<ChannelSigner>, update_id: MonitorUpdateId) -> ChannelMonitorUpdateStatus;
 }
 
 struct MonitorHolder<ChannelSigner: Sign> {
@@ -294,7 +294,7 @@ where C::Target: chain::Filter,
 				}
 
 				log_trace!(self.logger, "Syncing Channel Monitor for channel {}", log_funding_info!(monitor));
-				match self.persister.update_persisted_channel(*funding_outpoint, &None, monitor, update_id) {
+				match self.persister.update_persisted_channel(*funding_outpoint, None, monitor, update_id) {
 					ChannelMonitorUpdateStatus::Completed =>
 						log_trace!(self.logger, "Finished syncing Channel Monitor for channel {}", log_funding_info!(monitor)),
 					ChannelMonitorUpdateStatus::PermanentFailure => {
@@ -646,7 +646,7 @@ where C::Target: chain::Filter,
 
 	/// Note that we persist the given `ChannelMonitor` update while holding the
 	/// `ChainMonitor` monitors lock.
-	fn update_channel(&self, funding_txo: OutPoint, update: ChannelMonitorUpdate) -> ChannelMonitorUpdateStatus {
+	fn update_channel(&self, funding_txo: OutPoint, update: &ChannelMonitorUpdate) -> ChannelMonitorUpdateStatus {
 		// Update the monitor that watches the channel referred to by the given outpoint.
 		let monitors = self.monitors.read().unwrap();
 		match monitors.get(&funding_txo) {
@@ -664,15 +664,15 @@ where C::Target: chain::Filter,
 			Some(monitor_state) => {
 				let monitor = &monitor_state.monitor;
 				log_trace!(self.logger, "Updating ChannelMonitor for channel {}", log_funding_info!(monitor));
-				let update_res = monitor.update_monitor(&update, &self.broadcaster, &*self.fee_estimator, &self.logger);
+				let update_res = monitor.update_monitor(update, &self.broadcaster, &*self.fee_estimator, &self.logger);
 				if update_res.is_err() {
 					log_error!(self.logger, "Failed to update ChannelMonitor for channel {}.", log_funding_info!(monitor));
 				}
 				// Even if updating the monitor returns an error, the monitor's state will
 				// still be changed. So, persist the updated monitor despite the error.
-				let update_id = MonitorUpdateId::from_monitor_update(&update);
+				let update_id = MonitorUpdateId::from_monitor_update(update);
 				let mut pending_monitor_updates = monitor_state.pending_monitor_updates.lock().unwrap();
-				let persist_res = self.persister.update_persisted_channel(funding_txo, &Some(update), monitor, update_id);
+				let persist_res = self.persister.update_persisted_channel(funding_txo, Some(update), monitor, update_id);
 				match persist_res {
 					ChannelMonitorUpdateStatus::InProgress => {
 						pending_monitor_updates.push(update_id);

lightning/src/chain/mod.rs

@@ -312,7 +312,7 @@ pub trait Watch<ChannelSigner: Sign> {
 	/// [`ChannelMonitorUpdateStatus`] for invariants around returning an error.
 	///
 	/// [`update_monitor`]: channelmonitor::ChannelMonitor::update_monitor
-	fn update_channel(&self, funding_txo: OutPoint, update: ChannelMonitorUpdate) -> ChannelMonitorUpdateStatus;
+	fn update_channel(&self, funding_txo: OutPoint, update: &ChannelMonitorUpdate) -> ChannelMonitorUpdateStatus;
 
 	/// Returns any monitor events since the last call. Subsequent calls must only return new
 	/// events.

lightning/src/ln/chanmon_update_fail_tests.rs

@@ -147,9 +147,9 @@ fn test_monitor_and_persister_update_fail() {
 			// Check that even though the persister is returning a InProgress,
 			// because the update is bogus, ultimately the error that's returned
 			// should be a PermanentFailure.
-			if let ChannelMonitorUpdateStatus::PermanentFailure = chain_mon.chain_monitor.update_channel(outpoint, update.clone()) {} else { panic!("Expected monitor error to be permanent"); }
+			if let ChannelMonitorUpdateStatus::PermanentFailure = chain_mon.chain_monitor.update_channel(outpoint, &update) {} else { panic!("Expected monitor error to be permanent"); }
 			logger.assert_log_regex("lightning::chain::chainmonitor".to_string(), regex::Regex::new("Persistence of ChannelMonitorUpdate for channel [0-9a-f]* in progress").unwrap(), 1);
-			assert_eq!(nodes[0].chain_monitor.update_channel(outpoint, update), ChannelMonitorUpdateStatus::Completed);
+			assert_eq!(nodes[0].chain_monitor.update_channel(outpoint, &update), ChannelMonitorUpdateStatus::Completed);
 		} else { assert!(false); }
 	}
 

lightning/src/ln/channelmanager.rs

@@ -1709,7 +1709,7 @@ where
 
 					// Update the monitor with the shutdown script if necessary.
 					if let Some(monitor_update) = monitor_update {
-						let update_res = self.chain_monitor.update_channel(chan_entry.get().get_funding_txo().unwrap(), monitor_update);
+						let update_res = self.chain_monitor.update_channel(chan_entry.get().get_funding_txo().unwrap(), &monitor_update);
 						let (result, is_permanent) =
 							handle_monitor_update_res!(self, update_res, chan_entry.get_mut(), RAACommitmentOrder::CommitmentFirst, chan_entry.key(), NO_UPDATE);
 						if is_permanent {
@@ -1807,7 +1807,7 @@ where
 			// force-closing. The monitor update on the required in-memory copy should broadcast
 			// the latest local state, which is the best we can do anyway. Thus, it is safe to
 			// ignore the result here.
-			let _ = self.chain_monitor.update_channel(funding_txo, monitor_update);
+			let _ = self.chain_monitor.update_channel(funding_txo, &monitor_update);
 		}
 	}
 
@@ -2336,7 +2336,7 @@ where
 						chan)
 				} {
 					Some((update_add, commitment_signed, monitor_update)) => {
-						let update_err = self.chain_monitor.update_channel(chan.get().get_funding_txo().unwrap(), monitor_update);
+						let update_err = self.chain_monitor.update_channel(chan.get().get_funding_txo().unwrap(), &monitor_update);
 						let chan_id = chan.get().channel_id();
 						match (update_err,
 							handle_monitor_update_res!(self, update_err, chan,
@@ -3284,7 +3284,7 @@ where
 				BackgroundEvent::ClosingMonitorUpdate((funding_txo, update)) => {
 					// The channel has already been closed, so no use bothering to care about the
 					// monitor updating completing.
-					let _ = self.chain_monitor.update_channel(funding_txo, update);
+					let _ = self.chain_monitor.update_channel(funding_txo, &update);
 				},
 			}
 		}
@@ -3807,7 +3807,7 @@ where
 				match chan.get_mut().get_update_fulfill_htlc_and_commit(prev_hop.htlc_id, payment_preimage, &self.logger) {
 					Ok(msgs_monitor_option) => {
 						if let UpdateFulfillCommitFetch::NewClaim { msgs, htlc_value_msat, monitor_update } = msgs_monitor_option {
-							match self.chain_monitor.update_channel(chan.get().get_funding_txo().unwrap(), monitor_update) {
+							match self.chain_monitor.update_channel(chan.get().get_funding_txo().unwrap(), &monitor_update) {
 								ChannelMonitorUpdateStatus::Completed => {},
 								e => {
 									log_given_level!(self.logger, if e == ChannelMonitorUpdateStatus::PermanentFailure { Level::Error } else { Level::Debug },
@@ -3844,7 +3844,7 @@ where
 						}
 					},
 					Err((e, monitor_update)) => {
-						match self.chain_monitor.update_channel(chan.get().get_funding_txo().unwrap(), monitor_update) {
+						match self.chain_monitor.update_channel(chan.get().get_funding_txo().unwrap(), &monitor_update) {
 							ChannelMonitorUpdateStatus::Completed => {},
 							e => {
 								// TODO: This needs to be handled somehow - if we receive a monitor update
@@ -3880,7 +3880,7 @@ where
 			};
 			// We update the ChannelMonitor on the backward link, after
 			// receiving an `update_fulfill_htlc` from the forward link.
-			let update_res = self.chain_monitor.update_channel(prev_hop.outpoint, preimage_update);
+			let update_res = self.chain_monitor.update_channel(prev_hop.outpoint, &preimage_update);
 			if update_res != ChannelMonitorUpdateStatus::Completed {
 				// TODO: This needs to be handled somehow - if we receive a monitor update
 				// with a preimage we *must* somehow manage to propagate it to the upstream
@@ -4449,7 +4449,7 @@ where
 
 					// Update the monitor with the shutdown script if necessary.
 					if let Some(monitor_update) = monitor_update {
-						let update_res = self.chain_monitor.update_channel(chan_entry.get().get_funding_txo().unwrap(), monitor_update);
+						let update_res = self.chain_monitor.update_channel(chan_entry.get().get_funding_txo().unwrap(), &monitor_update);
 						let (result, is_permanent) =
 							handle_monitor_update_res!(self, update_res, chan_entry.get_mut(), RAACommitmentOrder::CommitmentFirst, chan_entry.key(), NO_UPDATE);
 						if is_permanent {
@@ -4650,13 +4650,13 @@ where
 						Err((None, e)) => try_chan_entry!(self, Err(e), chan),
 						Err((Some(update), e)) => {
 							assert!(chan.get().is_awaiting_monitor_update());
-							let _ = self.chain_monitor.update_channel(chan.get().get_funding_txo().unwrap(), update);
+							let _ = self.chain_monitor.update_channel(chan.get().get_funding_txo().unwrap(), &update);
 							try_chan_entry!(self, Err(e), chan);
 							unreachable!();
 						},
 						Ok(res) => res
 					};
-				let update_res = self.chain_monitor.update_channel(chan.get().get_funding_txo().unwrap(), monitor_update);
+				let update_res = self.chain_monitor.update_channel(chan.get().get_funding_txo().unwrap(), &monitor_update);
 				if let Err(e) = handle_monitor_update_res!(self, update_res, chan, RAACommitmentOrder::RevokeAndACKFirst, true, commitment_signed.is_some()) {
 					return Err(e);
 				}
@@ -4792,7 +4792,7 @@ where
 					let raa_updates = break_chan_entry!(self,
 						chan.get_mut().revoke_and_ack(&msg, &self.logger), chan);
 					htlcs_to_fail = raa_updates.holding_cell_failed_htlcs;
-					let update_res = self.chain_monitor.update_channel(chan.get().get_funding_txo().unwrap(), raa_updates.monitor_update);
+					let update_res = self.chain_monitor.update_channel(chan.get().get_funding_txo().unwrap(), &raa_updates.monitor_update);
 					if was_paused_for_mon_update {
 						assert!(update_res != ChannelMonitorUpdateStatus::Completed);
 						assert!(raa_updates.commitment_update.is_none());
@@ -5097,7 +5097,7 @@ where
 								));
 							}
 							if let Some((commitment_update, monitor_update)) = commitment_opt {
-								match self.chain_monitor.update_channel(chan.get_funding_txo().unwrap(), monitor_update) {
+								match self.chain_monitor.update_channel(chan.get_funding_txo().unwrap(), &monitor_update) {
 									ChannelMonitorUpdateStatus::Completed => {
 										pending_msg_events.push(events::MessageSendEvent::UpdateHTLCs {
 											node_id: chan.get_counterparty_node_id(),

lightning/src/ln/functional_tests.rs

@@ -8135,8 +8135,8 @@ fn test_update_err_monitor_lockdown() {
 		let mut node_0_peer_state_lock;
 		let mut channel = get_channel_ref!(nodes[0], nodes[1], node_0_per_peer_lock, node_0_peer_state_lock, chan_1.2);
 		if let Ok((_, _, update)) = channel.commitment_signed(&updates.commitment_signed, &node_cfgs[0].logger) {
-			assert_eq!(watchtower.chain_monitor.update_channel(outpoint, update.clone()), ChannelMonitorUpdateStatus::PermanentFailure);
-			assert_eq!(nodes[0].chain_monitor.update_channel(outpoint, update), ChannelMonitorUpdateStatus::Completed);
+			assert_eq!(watchtower.chain_monitor.update_channel(outpoint, &update), ChannelMonitorUpdateStatus::PermanentFailure);
+			assert_eq!(nodes[0].chain_monitor.update_channel(outpoint, &update), ChannelMonitorUpdateStatus::Completed);
 		} else { assert!(false); }
 	}
 	// Our local monitor is in-sync and hasn't processed yet timeout
@@ -8230,9 +8230,9 @@ fn test_concurrent_monitor_claim() {
 		let mut channel = get_channel_ref!(nodes[0], nodes[1], node_0_per_peer_lock, node_0_peer_state_lock, chan_1.2);
 		if let Ok((_, _, update)) = channel.commitment_signed(&updates.commitment_signed, &node_cfgs[0].logger) {
 			// Watchtower Alice should already have seen the block and reject the update
-			assert_eq!(watchtower_alice.chain_monitor.update_channel(outpoint, update.clone()), ChannelMonitorUpdateStatus::PermanentFailure);
-			assert_eq!(watchtower_bob.chain_monitor.update_channel(outpoint, update.clone()), ChannelMonitorUpdateStatus::Completed);
-			assert_eq!(nodes[0].chain_monitor.update_channel(outpoint, update), ChannelMonitorUpdateStatus::Completed);
+			assert_eq!(watchtower_alice.chain_monitor.update_channel(outpoint, &update), ChannelMonitorUpdateStatus::PermanentFailure);
+			assert_eq!(watchtower_bob.chain_monitor.update_channel(outpoint, &update), ChannelMonitorUpdateStatus::Completed);
+			assert_eq!(nodes[0].chain_monitor.update_channel(outpoint, &update), ChannelMonitorUpdateStatus::Completed);
 		} else { assert!(false); }
 	}
 	// Our local monitor is in-sync and hasn't processed yet timeout

lightning/src/util/persist.rs

@@ -94,7 +94,7 @@ impl<ChannelSigner: Sign, K: KVStorePersister> Persist<ChannelSigner> for K {
 		}
 	}
 
-	fn update_persisted_channel(&self, funding_txo: OutPoint, _update: &Option<ChannelMonitorUpdate>, monitor: &ChannelMonitor<ChannelSigner>, _update_id: MonitorUpdateId) -> chain::ChannelMonitorUpdateStatus {
+	fn update_persisted_channel(&self, funding_txo: OutPoint, _update: Option<&ChannelMonitorUpdate>, monitor: &ChannelMonitor<ChannelSigner>, _update_id: MonitorUpdateId) -> chain::ChannelMonitorUpdateStatus {
 		let key = format!("monitors/{}_{}", funding_txo.txid.to_hex(), funding_txo.index);
 		match self.persist(&key, monitor) {
 			Ok(()) => chain::ChannelMonitorUpdateStatus::Completed,

lightning/src/util/test_utils.rs

@@ -184,12 +184,12 @@ impl<'a> chain::Watch<EnforcingSigner> for TestChainMonitor<'a> {
 		self.chain_monitor.watch_channel(funding_txo, new_monitor)
 	}
 
-	fn update_channel(&self, funding_txo: OutPoint, update: channelmonitor::ChannelMonitorUpdate) -> chain::ChannelMonitorUpdateStatus {
+	fn update_channel(&self, funding_txo: OutPoint, update: &channelmonitor::ChannelMonitorUpdate) -> chain::ChannelMonitorUpdateStatus {
 		// Every monitor update should survive roundtrip
 		let mut w = TestVecWriter(Vec::new());
 		update.write(&mut w).unwrap();
 		assert!(channelmonitor::ChannelMonitorUpdate::read(
-				&mut io::Cursor::new(&w.0)).unwrap() == update);
+				&mut io::Cursor::new(&w.0)).unwrap() == *update);
 
 		self.monitor_updates.lock().unwrap().entry(funding_txo.to_channel_id()).or_insert(Vec::new()).push(update.clone());
 
@@ -202,7 +202,7 @@ impl<'a> chain::Watch<EnforcingSigner> for TestChainMonitor<'a> {
 		}
 
 		self.latest_monitor_update_id.lock().unwrap().insert(funding_txo.to_channel_id(),
-			(funding_txo, update.update_id, MonitorUpdateId::from_monitor_update(&update)));
+			(funding_txo, update.update_id, MonitorUpdateId::from_monitor_update(update)));
 		let update_res = self.chain_monitor.update_channel(funding_txo, update);
 		// At every point where we get a monitor update, we should be able to send a useful monitor
 		// to a watchtower and disk...
@@ -254,7 +254,7 @@ impl<Signer: keysinterface::Sign> chainmonitor::Persist<Signer> for TestPersiste
 		chain::ChannelMonitorUpdateStatus::Completed
 	}
 
-	fn update_persisted_channel(&self, funding_txo: OutPoint, update: &Option<channelmonitor::ChannelMonitorUpdate>, _data: &channelmonitor::ChannelMonitor<Signer>, update_id: MonitorUpdateId) -> chain::ChannelMonitorUpdateStatus {
+	fn update_persisted_channel(&self, funding_txo: OutPoint, update: Option<&channelmonitor::ChannelMonitorUpdate>, _data: &channelmonitor::ChannelMonitor<Signer>, update_id: MonitorUpdateId) -> chain::ChannelMonitorUpdateStatus {
 		let mut ret = chain::ChannelMonitorUpdateStatus::Completed;
 		if let Some(update_ret) = self.update_rets.lock().unwrap().pop_front() {
 			ret = update_ret;