Maintain order of yielded claim events
[rust-lightning] / lightning / src / chain / onchaintx.rs
index faf3fe12f60b1787494d803b77ce6abbe31b6017..2c570f580bd32153bb0488fd454a8345368f1436 100644 (file)
@@ -248,8 +248,19 @@ pub struct OnchainTxHandler<ChannelSigner: WriteableEcdsaChannelSigner> {
        pub(crate) pending_claim_requests: HashMap<PackageID, PackageTemplate>,
        #[cfg(not(test))]
        pending_claim_requests: HashMap<PackageID, PackageTemplate>,
+
+       // Used to track external events that need to be forwarded to the `ChainMonitor`. This `Vec`
+       // essentially acts as an insertion-ordered `HashMap` – there should only ever be one occurrence
+       // of a `PackageID`, which tracks its latest `ClaimEvent`, i.e., if a pending claim exists, and
+       // a new block has been connected, resulting in a new claim, the previous will be replaced with
+       // the new.
+       //
+       // These external events may be generated in the following cases:
+       //      - A channel has been force closed by broadcasting the holder's latest commitment transaction
+       //      - A block being connected/disconnected
+       //      - Learning the preimage for an HTLC we can claim onchain
        #[cfg(anchors)]
-       pending_claim_events: HashMap<PackageID, ClaimEvent>,
+       pending_claim_events: Vec<(PackageID, ClaimEvent)>,
 
        // Used to link outpoints claimed in a connected block to a pending claim request. The keys
        // represent the outpoints that our `ChannelMonitor` has detected we have keys/scripts to
@@ -426,7 +437,7 @@ impl<'a, 'b, ES: EntropySource, SP: SignerProvider> ReadableArgs<(&'a ES, &'b SP
                        pending_claim_requests,
                        onchain_events_awaiting_threshold_conf,
                        #[cfg(anchors)]
-                       pending_claim_events: HashMap::new(),
+                       pending_claim_events: Vec::new(),
                        secp_ctx,
                })
        }
@@ -447,8 +458,7 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
                        locktimed_packages: BTreeMap::new(),
                        onchain_events_awaiting_threshold_conf: Vec::new(),
                        #[cfg(anchors)]
-                       pending_claim_events: HashMap::new(),
-
+                       pending_claim_events: Vec::new(),
                        secp_ctx,
                }
        }
@@ -463,9 +473,9 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
 
        #[cfg(anchors)]
        pub(crate) fn get_and_clear_pending_claim_events(&mut self) -> Vec<ClaimEvent> {
-               let mut ret = HashMap::new();
-               swap(&mut ret, &mut self.pending_claim_events);
-               ret.into_iter().map(|(_, event)| event).collect::<Vec<_>>()
+               let mut events = Vec::new();
+               swap(&mut events, &mut self.pending_claim_events);
+               events.into_iter().map(|(_, event)| event).collect()
        }
 
        /// Lightning security model (i.e being able to redeem/timeout HTLC or penalize counterparty
@@ -709,7 +719,8 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
                                                                package_id
                                                        },
                                                };
-                                               self.pending_claim_events.insert(package_id, claim_event);
+                                               debug_assert_eq!(self.pending_claim_events.iter().filter(|entry| entry.0 == package_id).count(), 0);
+                                               self.pending_claim_events.push((package_id, claim_event));
                                                package_id
                                        },
                                };
@@ -794,6 +805,20 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
                                                        //TODO: recompute soonest_timelock to avoid wasting a bit on fees
                                                        if at_least_one_drop {
                                                                bump_candidates.insert(*package_id, request.clone());
+                                                               // If we have any pending claim events for the request being updated
+                                                               // that have yet to be consumed, we'll remove them since they will
+                                                               // end up producing an invalid transaction by double spending
+                                                               // input(s) that already have a confirmed spend. If such spend is
+                                                               // reorged out of the chain, then we'll attempt to re-spend the
+                                                               // inputs once we see it.
+                                                               #[cfg(anchors)] {
+                                                                       #[cfg(debug_assertions)] {
+                                                                               let existing = self.pending_claim_events.iter()
+                                                                                       .filter(|entry| entry.0 == *package_id).count();
+                                                                               assert!(existing == 0 || existing == 1);
+                                                                       }
+                                                                       self.pending_claim_events.retain(|entry| entry.0 != *package_id);
+                                                               }
                                                        }
                                                }
                                                break; //No need to iterate further, either tx is our or their
@@ -829,8 +854,14 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
                                                                log_debug!(logger, "Removing claim tracking for {} due to maturation of claim package {}.",
                                                                        outpoint, log_bytes!(package_id));
                                                                self.claimable_outpoints.remove(outpoint);
-                                                               #[cfg(anchors)]
-                                                               self.pending_claim_events.remove(&package_id);
+                                                       }
+                                                       #[cfg(anchors)] {
+                                                               #[cfg(debug_assertions)] {
+                                                                       let num_existing = self.pending_claim_events.iter()
+                                                                               .filter(|entry| entry.0 == package_id).count();
+                                                                       assert!(num_existing == 0 || num_existing == 1);
+                                                               }
+                                                               self.pending_claim_events.retain(|(id, _)| *id != package_id);
                                                        }
                                                }
                                        },
@@ -866,7 +897,13 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
                                        #[cfg(anchors)]
                                        OnchainClaim::Event(claim_event) => {
                                                log_info!(logger, "Yielding RBF-bumped onchain event to spend inputs {:?}", request.outpoints());
-                                               self.pending_claim_events.insert(*package_id, claim_event);
+                                               #[cfg(debug_assertions)] {
+                                                       let num_existing = self.pending_claim_events.iter().
+                                                               filter(|entry| entry.0 == *package_id).count();
+                                                       assert!(num_existing == 0 || num_existing == 1);
+                                               }
+                                               self.pending_claim_events.retain(|event| event.0 != *package_id);
+                                               self.pending_claim_events.push((*package_id, claim_event));
                                        },
                                }
                                if let Some(request) = self.pending_claim_requests.get_mut(package_id) {
@@ -930,7 +967,7 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
                                self.onchain_events_awaiting_threshold_conf.push(entry);
                        }
                }
-               for ((_package_id, _), request) in bump_candidates.iter_mut() {
+               for ((_package_id, _), ref mut request) in bump_candidates.iter_mut() {
                        if let Some((new_timer, new_feerate, bump_claim)) = self.generate_claim(height, &request, fee_estimator, &&*logger) {
                                request.set_timer(new_timer);
                                request.set_feerate(new_feerate);
@@ -942,7 +979,13 @@ impl<ChannelSigner: WriteableEcdsaChannelSigner> OnchainTxHandler<ChannelSigner>
                                        #[cfg(anchors)]
                                        OnchainClaim::Event(claim_event) => {
                                                log_info!(logger, "Yielding onchain event after reorg to spend inputs {:?}", request.outpoints());
-                                               self.pending_claim_events.insert(_package_id, claim_event);
+                                               #[cfg(debug_assertions)] {
+                                                       let num_existing = self.pending_claim_events.iter()
+                                                               .filter(|entry| entry.0 == *_package_id).count();
+                                                       assert!(num_existing == 0 || num_existing == 1);
+                                               }
+                                               self.pending_claim_events.retain(|event| event.0 != *_package_id);
+                                               self.pending_claim_events.push((*_package_id, claim_event));
                                        },
                                }
                        }