Merge pull request #840 from jkczyz/2021-03-rescan-logic
[rust-lightning] / lightning / src / chain / chainmonitor.rs
index eb17b469a0365df2de4464ef313cc243441b6767..0fd088019247e4e8e9adbea39adb99798e274dd4 100644 (file)
@@ -26,7 +26,7 @@
 use bitcoin::blockdata::block::{Block, BlockHeader};
 
 use chain;
-use chain::Filter;
+use chain::{Filter, WatchedOutput};
 use chain::chaininterface::{BroadcasterInterface, FeeEstimator};
 use chain::channelmonitor;
 use chain::channelmonitor::{ChannelMonitor, ChannelMonitorUpdate, ChannelMonitorUpdateErr, MonitorEvent, Persist};
@@ -82,18 +82,40 @@ where C::Target: chain::Filter,
        /// descendants of such transactions. It is not necessary to re-fetch the block to obtain
        /// updated `txdata`.
        pub fn block_connected(&self, header: &BlockHeader, txdata: &TransactionData, height: u32) {
+               let mut dependent_txdata = Vec::new();
                let monitors = self.monitors.read().unwrap();
                for monitor in monitors.values() {
                        let mut txn_outputs = monitor.block_connected(header, txdata, height, &*self.broadcaster, &*self.fee_estimator, &*self.logger);
 
+                       // Register any new outputs with the chain source for filtering, storing any dependent
+                       // transactions from within the block that previously had not been included in txdata.
                        if let Some(ref chain_source) = self.chain_source {
+                               let block_hash = header.block_hash();
                                for (txid, outputs) in txn_outputs.drain(..) {
                                        for (idx, output) in outputs.iter() {
-                                               chain_source.register_output(&OutPoint { txid, index: *idx as u16 }, &output.script_pubkey);
+                                               // Register any new outputs with the chain source for filtering and recurse
+                                               // if it indicates that there are dependent transactions within the block
+                                               // that had not been previously included in txdata.
+                                               let output = WatchedOutput {
+                                                       block_hash: Some(block_hash),
+                                                       outpoint: OutPoint { txid, index: *idx as u16 },
+                                                       script_pubkey: output.script_pubkey.clone(),
+                                               };
+                                               if let Some(tx) = chain_source.register_output(output) {
+                                                       dependent_txdata.push(tx);
+                                               }
                                        }
                                }
                        }
                }
+
+               // Recursively call for any dependent transactions that were identified by the chain source.
+               if !dependent_txdata.is_empty() {
+                       dependent_txdata.sort_unstable_by_key(|(index, _tx)| *index);
+                       dependent_txdata.dedup_by_key(|(index, _tx)| *index);
+                       let txdata: Vec<_> = dependent_txdata.iter().map(|(index, tx)| (*index, tx)).collect();
+                       self.block_connected(header, &txdata, height);
+               }
        }
 
        /// Dispatches to per-channel monitors, which are responsible for updating their on-chain view
@@ -245,3 +267,56 @@ impl<ChannelSigner: Sign, C: Deref, T: Deref, F: Deref, L: Deref, P: Deref> even
                pending_events
        }
 }
+
+#[cfg(test)]
+mod tests {
+       use ::{check_added_monitors, get_local_commitment_txn};
+       use ln::features::InitFeatures;
+       use ln::functional_test_utils::*;
+       use util::events::EventsProvider;
+       use util::events::MessageSendEventsProvider;
+       use util::test_utils::{OnRegisterOutput, TxOutReference};
+
+       /// Tests that in-block dependent transactions are processed by `block_connected` when not
+       /// included in `txdata` but returned by [`chain::Filter::register_output`]. For instance,
+       /// a (non-anchor) commitment transaction's HTLC output may be spent in the same block as the
+       /// commitment transaction itself. An Electrum client may filter the commitment transaction but
+       /// needs to return the HTLC transaction so it can be processed.
+       #[test]
+       fn connect_block_checks_dependent_transactions() {
+               let chanmon_cfgs = create_chanmon_cfgs(2);
+               let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
+               let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
+               let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
+               let channel = create_announced_chan_between_nodes(
+                       &nodes, 0, 1, InitFeatures::known(), InitFeatures::known());
+
+               // Send a payment, saving nodes[0]'s revoked commitment and HTLC-Timeout transactions.
+               let (commitment_tx, htlc_tx) = {
+                       let payment_preimage = route_payment(&nodes[0], &vec!(&nodes[1])[..], 5_000_000).0;
+                       let mut txn = get_local_commitment_txn!(nodes[0], channel.2);
+                       claim_payment(&nodes[0], &vec!(&nodes[1])[..], payment_preimage, 5_000_000);
+
+                       assert_eq!(txn.len(), 2);
+                       (txn.remove(0), txn.remove(0))
+               };
+
+               // Set expectations on nodes[1]'s chain source to return dependent transactions.
+               let htlc_output = TxOutReference(commitment_tx.clone(), 0);
+               let to_local_output = TxOutReference(commitment_tx.clone(), 1);
+               let htlc_timeout_output = TxOutReference(htlc_tx.clone(), 0);
+               nodes[1].chain_source
+                       .expect(OnRegisterOutput { with: htlc_output, returns: Some((1, htlc_tx)) })
+                       .expect(OnRegisterOutput { with: to_local_output, returns: None })
+                       .expect(OnRegisterOutput { with: htlc_timeout_output, returns: None });
+
+               // Notify nodes[1] that nodes[0]'s revoked commitment transaction was mined. The chain
+               // source should return the dependent HTLC transaction when the HTLC output is registered.
+               mine_transaction(&nodes[1], &commitment_tx);
+
+               // Clean up so uninteresting assertions don't fail.
+               check_added_monitors!(nodes[1], 1);
+               nodes[1].node.get_and_clear_pending_msg_events();
+               nodes[1].node.get_and_clear_pending_events();
+       }
+}