Reload pending payments from ChannelMonitor HTLC data on reload
[rust-lightning] / lightning / src / chain / channelmonitor.rs
index 7fad40d9c2ed70f4252115b3d2f98d16ee2ac2b7..8be785f29d2c38c3165023816e8821b1853418d1 100644 (file)
@@ -1515,6 +1515,101 @@ impl<Signer: Sign> ChannelMonitor<Signer> {
 
                res
        }
+
+       /// Gets the set of outbound HTLCs which are pending resolution in this channel.
+       /// This is used to reconstruct pending outbound payments on restart in the ChannelManager.
+       pub(crate) fn get_pending_outbound_htlcs(&self) -> HashMap<HTLCSource, HTLCOutputInCommitment> {
+               let mut res = HashMap::new();
+               let us = self.inner.lock().unwrap();
+
+               macro_rules! walk_htlcs {
+                       ($holder_commitment: expr, $htlc_iter: expr) => {
+                               for (htlc, source) in $htlc_iter {
+                                       if us.htlcs_resolved_on_chain.iter().any(|v| Some(v.input_idx) == htlc.transaction_output_index) {
+                                               // We should assert that funding_spend_confirmed is_some() here, but we
+                                               // have some unit tests which violate HTLC transaction CSVs entirely and
+                                               // would fail.
+                                               // TODO: Once tests all connect transactions at consensus-valid times, we
+                                               // should assert here like we do in `get_claimable_balances`.
+                                       } else if htlc.offered == $holder_commitment {
+                                               // If the payment was outbound, check if there's an HTLCUpdate
+                                               // indicating we have spent this HTLC with a timeout, claiming it back
+                                               // and awaiting confirmations on it.
+                                               let htlc_update_confd = us.onchain_events_awaiting_threshold_conf.iter().any(|event| {
+                                                       if let OnchainEvent::HTLCUpdate { input_idx: Some(input_idx), .. } = event.event {
+                                                               // If the HTLC was timed out, we wait for ANTI_REORG_DELAY blocks
+                                                               // before considering it "no longer pending" - this matches when we
+                                                               // provide the ChannelManager an HTLC failure event.
+                                                               Some(input_idx) == htlc.transaction_output_index &&
+                                                                       us.best_block.height() >= event.height + ANTI_REORG_DELAY - 1
+                                                       } else if let OnchainEvent::HTLCSpendConfirmation { input_idx, .. } = event.event {
+                                                               // If the HTLC was fulfilled with a preimage, we consider the HTLC
+                                                               // immediately non-pending, matching when we provide ChannelManager
+                                                               // the preimage.
+                                                               Some(input_idx) == htlc.transaction_output_index
+                                                       } else { false }
+                                               });
+                                               if !htlc_update_confd {
+                                                       res.insert(source.clone(), htlc.clone());
+                                               }
+                                       }
+                               }
+                       }
+               }
+
+               // We're only concerned with the confirmation count of HTLC transactions, and don't
+               // actually care how many confirmations a commitment transaction may or may not have. Thus,
+               // we look for either a FundingSpendConfirmation event or a funding_spend_confirmed.
+               let confirmed_txid = us.funding_spend_confirmed.or_else(|| {
+                       us.onchain_events_awaiting_threshold_conf.iter().find_map(|event| {
+                               if let OnchainEvent::FundingSpendConfirmation { .. } = event.event {
+                                       Some(event.txid)
+                               } else { None }
+                       })
+               });
+               if let Some(txid) = confirmed_txid {
+                       if Some(txid) == us.current_counterparty_commitment_txid || Some(txid) == us.prev_counterparty_commitment_txid {
+                               walk_htlcs!(false, us.counterparty_claimable_outpoints.get(&txid).unwrap().iter().filter_map(|(a, b)| {
+                                       if let &Some(ref source) = b {
+                                               Some((a, &**source))
+                                       } else { None }
+                               }));
+                       } else if txid == us.current_holder_commitment_tx.txid {
+                               walk_htlcs!(true, us.current_holder_commitment_tx.htlc_outputs.iter().filter_map(|(a, _, c)| {
+                                       if let Some(source) = c { Some((a, source)) } else { None }
+                               }));
+                       } else if let Some(prev_commitment) = &us.prev_holder_signed_commitment_tx {
+                               if txid == prev_commitment.txid {
+                                       walk_htlcs!(true, prev_commitment.htlc_outputs.iter().filter_map(|(a, _, c)| {
+                                               if let Some(source) = c { Some((a, source)) } else { None }
+                                       }));
+                               }
+                       }
+               } else {
+                       // If we have not seen a commitment transaction on-chain (ie the channel is not yet
+                       // closed), just examine the available counterparty commitment transactions. See docs
+                       // on `fail_unbroadcast_htlcs`, below, for justification.
+                       macro_rules! walk_counterparty_commitment {
+                               ($txid: expr) => {
+                                       if let Some(ref latest_outpoints) = us.counterparty_claimable_outpoints.get($txid) {
+                                               for &(ref htlc, ref source_option) in latest_outpoints.iter() {
+                                                       if let &Some(ref source) = source_option {
+                                                               res.insert((**source).clone(), htlc.clone());
+                                                       }
+                                               }
+                                       }
+                               }
+                       }
+                       if let Some(ref txid) = us.current_counterparty_commitment_txid {
+                               walk_counterparty_commitment!(txid);
+                       }
+                       if let Some(ref txid) = us.prev_counterparty_commitment_txid {
+                               walk_counterparty_commitment!(txid);
+                       }
+               }
+
+               res
+       }
 }
 
 /// Compares a broadcasted commitment transaction's HTLCs with those in the latest state,