Update monitor with preimage after channel close

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

diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs
index f3f13d3fb91f9f223651b396cd1acf5010b81163..a884b5f72d870a173f2d27986522ce2394f136ad 100644 (file)
--- a/lightning/src/ln/channelmanager.rs
+++ b/lightning/src/ln/channelmanager.rs
@@ -37,7 +37,7 @@ use bitcoin::secp256k1;
 use chain;
 use chain::Watch;
 use chain::chaininterface::{BroadcasterInterface, FeeEstimator};
-use chain::channelmonitor::{ChannelMonitor, ChannelMonitorUpdate, ChannelMonitorUpdateErr, HTLC_FAIL_BACK_BUFFER, CLTV_CLAIM_BUFFER, LATENCY_GRACE_PERIOD_BLOCKS, ANTI_REORG_DELAY, MonitorEvent};
+use chain::channelmonitor::{ChannelMonitor, ChannelMonitorUpdate, ChannelMonitorUpdateStep, ChannelMonitorUpdateErr, HTLC_FAIL_BACK_BUFFER, CLTV_CLAIM_BUFFER, LATENCY_GRACE_PERIOD_BLOCKS, ANTI_REORG_DELAY, MonitorEvent, CLOSED_CHANNEL_UPDATE_ID};
 use chain::transaction::{OutPoint, TransactionData};
 use ln::channel::{Channel, ChannelError};
 use ln::features::{InitFeatures, NodeFeatures};
@@ -2152,12 +2152,23 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
                                });
                        },
                        HTLCSource::PreviousHopData(hop_data) => {
+                               let prev_outpoint = hop_data.outpoint;
                                if let Err((counterparty_node_id, err)) = match self.claim_funds_from_hop(&mut channel_state_lock, hop_data, payment_preimage) {
                                        Ok(()) => Ok(()),
                                        Err(None) => {
-                                               // TODO: There is probably a channel monitor somewhere that needs to
-                                               // learn the preimage as the channel already hit the chain and that's
-                                               // why it's missing.
+                                               let preimage_update = ChannelMonitorUpdate {
+                                                       update_id: CLOSED_CHANNEL_UPDATE_ID,
+                                                       updates: vec![ChannelMonitorUpdateStep::PaymentPreimage {
+                                                               payment_preimage: payment_preimage.clone(),
+                                                       }],
+                                               };
+                                               // We update the ChannelMonitor on the backward link, after
+                                               // receiving an offchain preimage event from the forward link (the
+                                               // event being update_fulfill_htlc).
+                                               if let Err(e) = self.chain_monitor.update_channel(prev_outpoint, preimage_update) {
+                                                       log_error!(self.logger, "Critical error: failed to update channel monitor with preimage {:?}: {:?}",
+                                                                  payment_preimage, e);
+                                               }
                                                Ok(())
                                        },
                                        Err(Some(res)) => Err(res),