Start auto-close timer if inbound update_fee don't complete

Author: Antoine Riard

lightning/src/ln/channelmanager.rs

@@ -2970,13 +2970,23 @@ 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 the channel is inbound and we detect a relevant feerate increase, we assume
+		// that our counterparty, reasonably implemented, should send us an `update_fee`
+		// soon. Monitoring this situation, we start an autoclose timer.
+		let background_feerate = self.fee_estimator.get_est_sat_per_1000_weight(ConfirmationTarget::Background);
+		if !chan.is_outbound() {
+			if chan.maybe_trigger_autoclose_timer(chan.get_feerate(), new_feerate, background_feerate) {
+				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);