fix duplicate HTLC fail-back on stale force-close

Author: Anyitechs

lightning/src/chain/channelmonitor.rs

@@ -1356,7 +1356,7 @@ pub(crate) struct ChannelMonitorImpl<Signer: EcdsaChannelSigner> {
 /// a downstream channel force-close remaining unconfirmed by the time the upstream timeout
 /// expires. This is used to tell us we already generated an event to fail this HTLC back
 /// during a previous block scan.
-failed_back_htlc_ids: HashSet<SentHTLCId>,
+failed_back_htlc_ids: HashMap<SentHTLCId, u64>,
 
 // The auxiliary HTLC data associated with a holder commitment transaction. This includes
 // non-dust HTLC sources, along with dust HTLCs and their sources. Note that this assumes any
@@ -1956,7 +1956,7 @@ impl<Signer: EcdsaChannelSigner> ChannelMonitor<Signer> {
 initial_counterparty_commitment_tx: None,
 balances_empty_height: None,
 
-failed_back_htlc_ids: new_hash_set(),
+failed_back_htlc_ids: new_hash_map(),
 
 // There are never any HTLCs in the initial commitment transaction
 current_holder_htlc_data: CommitmentHTLCData::new(),
@@ -5523,7 +5523,7 @@ impl<Signer: EcdsaChannelSigner> ChannelMonitorImpl<Signer> {
 let mut matured_htlcs = Vec::new();
 
 // Produce actionable events from on-chain events having reached their threshold.
-for entry in onchain_events_reaching_threshold_conf {
+for entry in onchain_events_reaching_threshold_conf.clone() {
 match entry.event {
 OnchainEvent::HTLCUpdate { source, payment_hash, htlc_value_satoshis, commitment_tx_output_idx } => {
 // Check for duplicate HTLC resolutions.
@@ -5587,6 +5587,85 @@ impl<Signer: EcdsaChannelSigner> ChannelMonitorImpl<Signer> {
 });
 }
 }
+
+// Only act on stale force-closes where the confirmed funding spend is the
+// previous counterparty commitment transaction.
+let prev_txid = match self.funding.prev_counterparty_commitment_txid {
+Some(txid) => {
+if txid != entry.txid { continue; }
+txid
+},
+None => { continue; }
+};
+
+// Process only HTLCs from that previous counterparty commitment.
+let prev_outputs = if let Some(outputs) =
+self.funding.counterparty_claimable_outpoints.get(&prev_txid) {
+outputs
+} else { continue; };
+
+// Build the set of HTLC ids present in the stale (previous) commitment.
+let mut prev_ids: HashSet<SentHTLCId> = new_hash_set();
+for &(_, ref source_opt) in prev_outputs.iter() {
+if let Some(source) = source_opt.as_ref() {
+prev_ids.insert(SentHTLCId::from_source(&**source));
+}
+}
+
+ // Avoid duplicate fail-back if an HTLCUpdate for this source has already been
+ // generated (either matured or still awaiting maturity).
+ let mut seen_monitor_htlc_ids: HashSet<SentHTLCId> = new_hash_set();
+ for e in onchain_events_reaching_threshold_conf.iter() {
+ if let OnchainEvent::HTLCUpdate { source, .. } = &e.event {
+ seen_monitor_htlc_ids.insert(SentHTLCId::from_source(source));
+ }
+ }
+ for e in self.onchain_events_awaiting_threshold_conf.iter() {
+ if let OnchainEvent::HTLCUpdate { source, .. } = &e.event {
+ seen_monitor_htlc_ids.insert(SentHTLCId::from_source(source));
+ }
+ }
+
+// Consider current live HTLCs (holder + current counterparty) with sources,
+// and fail back only those NOT present in the stale (previous) commitment.
+ let current_counterparty_iter = if let Some(txid) = self.funding.current_counterparty_commitment_txid {
+ if let Some(htlc_outputs) = self.funding.counterparty_claimable_outpoints.get(&txid) {
+ Some(htlc_outputs.iter().map(|&(ref a, ref b)| (a, b.as_ref().map(|boxed| &**boxed))))
+ } else { None }
+ } else { None }.into_iter().flatten();
+ let current_htlcs = holder_commitment_htlcs!(self, CURRENT_WITH_SOURCES)
+ .chain(current_counterparty_iter);
+
+ // Count expected duplicates per id from the current view to bound emissions.
+ let mut expected_current_counts: HashMap<SentHTLCId, u64> = new_hash_map();
+ for (_, source_opt) in current_htlcs.clone() {
+ if let Some(source) = source_opt { *expected_current_counts.entry(SentHTLCId::from_source(source)).or_default() += 1; }
+ }
+
+for (htlc, source_opt) in current_htlcs {
+if let Some(source) = source_opt {
+
+let sent_id = SentHTLCId::from_source(source);
+if prev_ids.contains(&sent_id) { continue; }
+if seen_monitor_htlc_ids.contains(&sent_id) { continue; }
+
+let already_emitted_count = *self.failed_back_htlc_ids.get(&sent_id).unwrap_or(&0);
+let expected_count = *expected_current_counts.get(&sent_id).unwrap_or(&0);
+
+if already_emitted_count < expected_count {
+log_info!(logger,
+"Detected stale force-close. Failing back all HTLCs for hash {}.",
+&htlc.payment_hash);
+self.pending_monitor_events.push(MonitorEvent::HTLCEvent(HTLCUpdate {
+source: source.clone(),
+payment_preimage: None,
+payment_hash: htlc.payment_hash,
+htlc_value_satoshis: Some(htlc.amount_msat / 1000),
+}));
+*self.failed_back_htlc_ids.entry(sent_id).or_default() += 1;
+}
+}
+}
 },
 OnchainEvent::AlternativeFundingConfirmation {} => {
 // An alternative funding transaction has irrevocably confirmed and we're no
@@ -5646,7 +5725,8 @@ impl<Signer: EcdsaChannelSigner> ChannelMonitorImpl<Signer> {
 if duplicate_event {
 continue;
 }
-if !self.failed_back_htlc_ids.insert(SentHTLCId::from_source(source)) {
+let htlc_id = SentHTLCId::from_source(source);
+if *self.failed_back_htlc_ids.get(&htlc_id).unwrap_or(&0) > 0 {
 continue;
 }
 if !duplicate_event {
@@ -5659,6 +5739,7 @@ impl<Signer: EcdsaChannelSigner> ChannelMonitorImpl<Signer> {
 payment_hash: htlc.payment_hash,
 htlc_value_satoshis: Some(htlc.amount_msat / 1000),
 }));
+*self.failed_back_htlc_ids.entry(htlc_id).or_default() += 1;
 }
 }
 }
@@ -6650,7 +6731,7 @@ impl<'a, 'b, ES: EntropySource, SP: SignerProvider> ReadableArgs<(&'a ES, &'b SP
 initial_counterparty_commitment_info,
 initial_counterparty_commitment_tx,
 balances_empty_height,
-failed_back_htlc_ids: new_hash_set(),
+failed_back_htlc_ids: new_hash_map(),
 
 current_holder_htlc_data,
 prev_holder_htlc_data,

lightning/src/ln/functional_tests.rs

@@ -33,8 +33,8 @@ use crate::ln::channel::{
 MIN_CHAN_DUST_LIMIT_SATOSHIS, UNFUNDED_CHANNEL_AGE_LIMIT_TICKS,
 };
 use crate::ln::channelmanager::{
-PaymentId, RAACommitmentOrder, RecipientOnionFields, BREAKDOWN_TIMEOUT, DISABLE_GOSSIP_TICKS,
-ENABLE_GOSSIP_TICKS, MIN_CLTV_EXPIRY_DELTA,
+PaymentId, RAACommitmentOrder, RecipientOnionFields, Retry, BREAKDOWN_TIMEOUT,
+DISABLE_GOSSIP_TICKS, ENABLE_GOSSIP_TICKS, MIN_CLTV_EXPIRY_DELTA,
 };
 use crate::ln::msgs;
 use crate::ln::msgs::{
@@ -9703,3 +9703,147 @@ pub fn test_multi_post_event_actions() {
 do_test_multi_post_event_actions(true);
 do_test_multi_post_event_actions(false);
 }
+
+#[xtest(feature = "_externalize_tests")]
+fn test_stale_force_close_with_identical_htlcs() {
+// Test that when two identical HTLCs are relayed and force-closes
+// with a stale state, that we fail both HTLCs back immediately.
+let chanmon_cfgs = create_chanmon_cfgs(4);
+let node_cfgs = create_node_cfgs(4, &chanmon_cfgs);
+let node_chanmgrs = create_node_chanmgrs(4, &node_cfgs, &[None, None, None, None]);
+let mut nodes = create_network(4, &node_cfgs, &node_chanmgrs);
+
+let chan_a_b = create_announced_chan_between_nodes(&nodes, 0, 1);
+let _chan_b_c = create_announced_chan_between_nodes(&nodes, 1, 2);
+let _chan_d_b = create_announced_chan_between_nodes(&nodes, 3, 1);
+
+let (_payment_preimage, payment_hash, payment_secret) = get_payment_preimage_hash!(nodes[2]);
+
+let payment_params = PaymentParameters::from_node_id(nodes[2].node.get_our_node_id(), 100);
+let scorer = test_utils::TestScorer::new();
+let random_seed_bytes = chanmon_cfgs[1].keys_manager.get_secure_random_bytes();
+let route_params = RouteParameters::from_payment_params_and_value(payment_params, 1_000_000);
+
+let route = get_route(
+&nodes[0].node.get_our_node_id(),
+&route_params,
+&nodes[0].network_graph.read_only(),
+None,
+nodes[0].logger,
+&scorer,
+&Default::default(),
+&random_seed_bytes,
+)
+.unwrap();
+
+nodes[0].router.expect_find_route(route_params.clone(), Ok(route.clone()));
+nodes[0]
+.node
+.send_payment(
+payment_hash,
+RecipientOnionFields::secret_only(payment_secret),
+PaymentId([1; 32]),
+route_params.clone(),
+Retry::Attempts(0),
+)
+.unwrap();
+
+let ev1 = remove_first_msg_event_to_node(
+&nodes[1].node.get_our_node_id(),
+&mut nodes[0].node.get_and_clear_pending_msg_events(),
+);
+let mut send_ev1 = SendEvent::from_event(ev1);
+
+nodes[1].node.handle_update_add_htlc(nodes[0].node.get_our_node_id(), &send_ev1.msgs[0]);
+nodes[1].node.handle_commitment_signed_batch_test(
+nodes[0].node.get_our_node_id(),
+&send_ev1.commitment_msg,
+);
+
+let mut b_events = nodes[1].node.get_and_clear_pending_msg_events();
+for ev in b_events.drain(..) {
+match ev {
+MessageSendEvent::SendRevokeAndACK { node_id, msg } => {
+assert_eq!(node_id, nodes[0].node.get_our_node_id());
+nodes[0].node.handle_revoke_and_ack(nodes[1].node.get_our_node_id(), &msg);
+},
+MessageSendEvent::UpdateHTLCs { node_id, updates, .. } => {
+assert_eq!(node_id, nodes[0].node.get_our_node_id());
+nodes[0].node.handle_commitment_signed_batch_test(
+nodes[1].node.get_our_node_id(),
+&updates.commitment_signed,
+);
+let mut a_events = nodes[0].node.get_and_clear_pending_msg_events();
+for a_ev in a_events.drain(..) {
+if let MessageSendEvent::SendRevokeAndACK { node_id, msg } = a_ev {
+assert_eq!(node_id, nodes[1].node.get_our_node_id());
+nodes[1].node.handle_revoke_and_ack(nodes[0].node.get_our_node_id(), &msg);
+}
+}
+},
+_ => {},
+}
+}
+
+nodes[1].node.process_pending_htlc_forwards();
+let _ = nodes[1].node.get_and_clear_pending_msg_events();
+
+let stale_commitment_tx = get_local_commitment_txn!(nodes[0], chan_a_b.2)[0].clone();
+
+*nodes[0].network_payment_count.borrow_mut() -= 1;
+nodes[0].router.expect_find_route(route_params.clone(), Ok(route.clone()));
+nodes[0]
+.node
+.send_payment(
+payment_hash,
+RecipientOnionFields::secret_only(payment_secret),
+PaymentId([2; 32]),
+route_params.clone(),
+Retry::Attempts(0),
+)
+.unwrap();
+
+let ev2 = remove_first_msg_event_to_node(
+&nodes[1].node.get_our_node_id(),
+&mut nodes[0].node.get_and_clear_pending_msg_events(),
+);
+let mut send_ev2 = SendEvent::from_event(ev2);
+
+nodes[1].node.handle_update_add_htlc(nodes[0].node.get_our_node_id(), &send_ev2.msgs[0]);
+nodes[1].node.handle_commitment_signed_batch_test(
+nodes[0].node.get_our_node_id(),
+&send_ev2.commitment_msg,
+);
+
+let mut b2_events = nodes[1].node.get_and_clear_pending_msg_events();
+for ev in b2_events.drain(..) {
+match ev {
+MessageSendEvent::SendRevokeAndACK { node_id, msg } => {
+assert_eq!(node_id, nodes[0].node.get_our_node_id());
+nodes[0].node.handle_revoke_and_ack(nodes[1].node.get_our_node_id(), &msg);
+},
+MessageSendEvent::UpdateHTLCs { node_id, updates, .. } => {
+assert_eq!(node_id, nodes[0].node.get_our_node_id());
+nodes[0].node.handle_commitment_signed_batch_test(
+nodes[1].node.get_our_node_id(),
+&updates.commitment_signed,
+);
+},
+_ => {},
+}
+}
+
+nodes[1].node.process_pending_htlc_forwards();
+let _ = nodes[1].node.get_and_clear_pending_msg_events();
+
+mine_transaction(&nodes[1], &stale_commitment_tx);
+connect_blocks(&nodes[1], ANTI_REORG_DELAY);
+
+let events = nodes[1].node.get_and_clear_pending_events();
+let failed_count =
+events.iter().filter(|e| matches!(e, Event::HTLCHandlingFailed { .. })).count();
+assert_eq!(failed_count, 2);
+
+check_added_monitors!(&nodes[1], 1);
+nodes[1].node.get_and_clear_pending_msg_events();
+}