f set proper error code in HTLC timeouts from channel

Author: TheBlueMatt

lightning/src/ln/channel.rs

@@ -3139,13 +3139,16 @@ impl<ChanSigner: ChannelKeys> Channel<ChanSigner> {
 	/// In case of Err, the channel may have been closed, at which point the standard requirements
 	/// apply - no calls may be made except those explicitly stated to be allowed post-shutdown.
 	/// Only returns an ErrorAction of DisconnectPeer, if Err.
-	pub fn block_connected(&mut self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[u32]) -> Result<(Option<msgs::FundingLocked>, Vec<(HTLCSource, PaymentHash, u64)>), msgs::ErrorMessage> {
+	///
+	/// May return some HTLCs (and their payment_hash) which have timed out and should be failed
+	/// back.
+	pub fn block_connected(&mut self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], indexes_of_txn_matched: &[u32]) -> Result<(Option<msgs::FundingLocked>, Vec<(HTLCSource, PaymentHash)>), msgs::ErrorMessage> {
 		let mut timed_out_htlcs = Vec::new();
 		self.holding_cell_htlc_updates.retain(|htlc_update| {
 			match htlc_update {
-				&HTLCUpdateAwaitingACK::AddHTLC { ref payment_hash, ref source, ref cltv_expiry, ref amount_msat, .. } => {
+				&HTLCUpdateAwaitingACK::AddHTLC { ref payment_hash, ref source, ref cltv_expiry, .. } => {
 					if cltv_expiry - CLTV_CLAIM_BUFFER - LATENCY_GRACE_PERIOD_BLOCKS <= height {
-						timed_out_htlcs.push((source.clone(), payment_hash.clone(), *amount_msat));
+						timed_out_htlcs.push((source.clone(), payment_hash.clone()));
 						false
 					} else { true }
 				},

lightning/src/ln/channelmanager.rs

@@ -2991,7 +2991,13 @@ impl<ChanSigner: ChannelKeys, M: Deref + Sync + Send, T: Deref + Sync + Send, K:
 			channel_state.by_id.retain(|_, channel| {
 				let res = channel.block_connected(header, height, txn_matched, indexes_of_txn_matched);
 				if let Ok((chan_res, mut timed_out_pending_htlcs)) = res {
-					timed_out_htlcs.append(&mut timed_out_pending_htlcs);
+					for (source, payment_hash) in timed_out_pending_htlcs.drain(..) {
+						let chan_update = self.get_channel_update(&channel).map(|u| u.encode_with_len()).unwrap(); // Cannot add/recv HTLCs before we have a short_id so unwrap is safe
+						timed_out_htlcs.push((source, payment_hash,  HTLCFailReason::Reason {
+							failure_code: 0x1000 | 14, // expiry_too_soon, or at least it is now
+							data: chan_update,
+						}));
+					}
 					if let Some(funding_locked) = chan_res {
 						pending_msg_events.push(events::MessageSendEvent::SendFundingLocked {
 							node_id: channel.get_their_node_id(),