Ensure all HTLCs for a claimed payment are claimed on startup

[rust-lightning] / lightning / src / ln / channelmanager.rs

diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs
index 71ae6170aa614cd6c5fb672c444d0891b7e03863..a62f44806d45ad617f369b47018538b1c31747c7 100644 (file)
--- a/lightning/src/ln/channelmanager.rs
+++ b/lightning/src/ln/channelmanager.rs
@@ -6698,7 +6698,7 @@ impl<'a, Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
                        // payments which are still in-flight via their on-chain state.
                        // We only rebuild the pending payments map if we were most recently serialized by
                        // 0.0.102+
-                       for (_, monitor) in args.channel_monitors {
+                       for (_, monitor) in args.channel_monitors.iter() {
                                if by_id.get(&monitor.get_funding_txo().0.to_channel_id()).is_none() {
                                        for (htlc_source, htlc) in monitor.get_pending_outbound_htlcs() {
                                                if let HTLCSource::OutboundRoute { payment_id, session_priv, path, payment_secret, .. } = htlc_source {
@@ -6824,6 +6824,38 @@ impl<'a, Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
                        }
                }
 
+               for (_, monitor) in args.channel_monitors.iter() {
+                       for (payment_hash, payment_preimage) in monitor.get_stored_preimages() {
+                               if let Some(claimable_htlcs) = claimable_htlcs.remove(&payment_hash) {
+                                       log_info!(args.logger, "Re-claimaing HTLCs with payment hash {} due to partial-claim.", log_bytes!(payment_hash.0));
+                                       for claimable_htlc in claimable_htlcs.1 {
+                                               // Add a holding-cell claim of the payment to the Channel, which should be
+                                               // applied ~immediately on peer reconnection. Because it won't generate a
+                                               // new commitment transaction we can just provide the payment preimage to
+                                               // the corresponding ChannelMonitor and nothing else.
+                                               //
+                                               // We do so directly instead of via the normal ChannelMonitor update
+                                               // procedure as the ChainMonitor hasn't yet been initialized, implying
+                                               // we're not allowed to call it directly yet. Further, we do the update
+                                               // without incrementing the ChannelMonitor update ID as there isn't any
+                                               // reason to.
+                                               // If we were to generate a new ChannelMonitor update ID here and then
+                                               // crash before the user finishes block connect we'd end up force-closing
+                                               // this channel as well. On the flip side, there's no harm in restarting
+                                               // without the new monitor persisted - we'll end up right back here on
+                                               // restart.
+                                               let previous_channel_id = claimable_htlc.prev_hop.outpoint.to_channel_id();
+                                               if let Some(channel) = by_id.get_mut(&previous_channel_id) {
+                                                       channel.claim_htlc_while_disconnected_dropping_mon_update(claimable_htlc.prev_hop.htlc_id, payment_preimage, &args.logger);
+                                               }
+                                               if let Some(previous_hop_monitor) = args.channel_monitors.get(&claimable_htlc.prev_hop.outpoint) {
+                                                       previous_hop_monitor.provide_payment_preimage(&payment_hash, &payment_preimage, &args.tx_broadcaster, &args.fee_estimator, &args.logger);
+                                               }
+                                       }
+                               }
+                       }
+               }
+
                let channel_manager = ChannelManager {
                        genesis_hash,
                        fee_estimator: args.fee_estimator,