Add auto-close if inbound feerate update don't complete

Author: Antoine Riard

lightning/src/ln/channel.rs

@@ -386,6 +386,9 @@ pub(super) struct Channel<Signer: Sign> {
 	// Auto-close timer, if the channel is outbound, we sent a `update_fee`, and we didn't
 	// receive a RAA from counterparty committing this state after `AUTOCLOSE_TIMEOUT` periods,
 	// this channel must be force-closed.
+	// If the channel is inbound, it has been observed the channel feerate should increase,
+	// and we didn't receive a RAA from counterparty committing an `update_fee` after
+	// `AUTOCLOSE_TIMEOUT` periods, this channel must be force-closed.
 	autoclose_timer: u16,
 
 	holder_signer: Signer,
@@ -2722,15 +2725,17 @@ impl<Signer: Sign> Channel<Signer> {
 	}
 
 	/// Trigger the autoclose timer if it's in the starting position
-	fn maybe_trigger_autoclose_timer(&mut self) {
+	pub fn maybe_trigger_autoclose_timer(&mut self) -> bool {
 		// Start an auto-close timer, if the channel feerate doesn't increase before its
 		// expiration (i.e this outbound feerate update has been committed on both sides),
 		// the channel will be marked as unsafe and force-closed.
 		// If a timer is already pending, no-op, as a higher-feerate `update_fee` will
 		// implicitly override a lower-feerate `update_fee` part of the same update sequence.
 		if self.autoclose_timer == 0 {
 			self.autoclose_timer = 1;
+			return true;
 		}
+		return false;
 	}
 
 	/// Handles receiving a remote's revoke_and_ack. Note that we may return a new
@@ -2907,6 +2912,7 @@ impl<Signer: Sign> Channel<Signer> {
 					require_commitment = true;
 					self.feerate_per_kw = feerate;
 					self.pending_update_fee = None;
+					self.autoclose_timer = 0;
 				},
 			}
 		}
@@ -4712,6 +4718,7 @@ impl<Signer: Sign> Channel<Signer> {
 				log_trace!(logger, " ...promoting inbound AwaitingRemoteRevokeToAnnounce fee update {} to Committed", feerate);
 				self.feerate_per_kw = feerate;
 				self.pending_update_fee = None;
+				self.autoclose_timer = 0;
 			}
 		}
 		self.resend_order = RAACommitmentOrder::RevokeAndACKFirst;

lightning/src/ln/channelmanager.rs

@@ -2819,13 +2819,19 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 	}
 
 	fn update_channel_fee(&self, short_to_id: &mut HashMap<u64, [u8; 32]>, pending_msg_events: &mut Vec<events::MessageSendEvent>, chan_id: &[u8; 32], chan: &mut Channel<Signer>, new_feerate: u32) -> (bool, NotifyOption, Result<(), MsgHandleErrInternal>) {
-		if !chan.is_outbound() { return (true, NotifyOption::SkipPersist, Ok(())); }
 		// If the feerate has decreased by less than half, don't bother
 		if new_feerate <= chan.get_feerate() && new_feerate * 2 > chan.get_feerate() {
 			log_trace!(self.logger, "Channel {} does not qualify for a feerate change from {} to {}.",
 				log_bytes!(chan_id[..]), chan.get_feerate(), new_feerate);
 			return (true, NotifyOption::SkipPersist, Ok(()));
 		}
+		if !chan.is_outbound() {
+			if chan.maybe_trigger_autoclose_timer() {
+				return (true, NotifyOption::DoPersist, Ok(()));
+			} else {
+				return (true, NotifyOption::SkipPersist, Ok(()));
+			}
+		}
 		if !chan.is_live() {
 			log_trace!(self.logger, "Channel {} does not qualify for a feerate change from {} to {} as it cannot currently be updated (probably the peer is disconnected).",
 				log_bytes!(chan_id[..]), chan.get_feerate(), new_feerate);