From 0bb87ddad71d2e33199ebad79e9f709f869f2130 Mon Sep 17 00:00:00 2001 From: Matt Corallo Date: Thu, 17 Nov 2022 05:55:45 +0000 Subject: [PATCH] Avoid attempting to forward to a closed chan on stale-data reload If, after forwarding a payment to our counterparty, we restart with a ChannelMonitor update having been persisted, but the corresponding ChannelManager update was not persisted, we'll still have the forwarded HTLC in the `forward_htlcs` map on start. This will cause us to generate a (spurious) `PendingHTLCsForwardable` event. However, when we go to forward said HTLC, we'll notice the channel has been closed and leave it up to the `ChannelMontior` to finalize the HTLC. This is all fine today - we won't lose any funds, we'll just generate an excess forwardable event and then fail to forward. However, in the future when we allow for forward-time channel changes this could break. Thus, its worth adding tests for this behavior today, and, while we're at it, removing the spurious forwardable HTLCs event. --- lightning/src/ln/channelmanager.rs | 44 ++++++-- lightning/src/ln/functional_test_utils.rs | 6 +- lightning/src/ln/reload_tests.rs | 124 +++++++++++++++++++++- 3 files changed, 160 insertions(+), 14 deletions(-) diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs index 352672647..2d84bb9cd 100644 --- a/lightning/src/ln/channelmanager.rs +++ b/lightning/src/ln/channelmanager.rs @@ -7286,16 +7286,6 @@ impl<'a, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> None => continue, } } - if forward_htlcs_count > 0 { - // If we have pending HTLCs to forward, assume we either dropped a - // `PendingHTLCsForwardable` or the user received it but never processed it as they - // shut down before the timer hit. Either way, set the time_forwardable to a small - // constant as enough time has likely passed that we should simply handle the forwards - // now, or at least after the user gets a chance to reconnect to our peers. - pending_events_read.push(events::Event::PendingHTLCsForwardable { - time_forwardable: Duration::from_secs(2), - }); - } let background_event_count: u64 = Readable::read(reader)?; let mut pending_background_events_read: Vec = Vec::with_capacity(cmp::min(background_event_count as usize, MAX_ALLOC_SIZE/mem::size_of::())); @@ -7404,10 +7394,44 @@ impl<'a, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> } } } + for (htlc_source, htlc) in monitor.get_all_current_outbound_htlcs() { + if let HTLCSource::PreviousHopData(prev_hop_data) = htlc_source { + // The ChannelMonitor is now responsible for this HTLC's + // failure/success and will let us know what its outcome is. If we + // still have an entry for this HTLC in `forward_htlcs`, we were + // apparently not persisted after the monitor was when forwarding + // the payment. + forward_htlcs.retain(|_, forwards| { + forwards.retain(|forward| { + if let HTLCForwardInfo::AddHTLC(htlc_info) = forward { + if htlc_info.prev_short_channel_id == prev_hop_data.short_channel_id && + htlc_info.prev_htlc_id == prev_hop_data.htlc_id + { + log_info!(args.logger, "Removing pending to-forward HTLC with hash {} as it was forwarded to the closed channel {}", + log_bytes!(htlc.payment_hash.0), log_bytes!(monitor.get_funding_txo().0.to_channel_id())); + false + } else { true } + } else { true } + }); + !forwards.is_empty() + }) + } + } } } } + if !forward_htlcs.is_empty() { + // If we have pending HTLCs to forward, assume we either dropped a + // `PendingHTLCsForwardable` or the user received it but never processed it as they + // shut down before the timer hit. Either way, set the time_forwardable to a small + // constant as enough time has likely passed that we should simply handle the forwards + // now, or at least after the user gets a chance to reconnect to our peers. + pending_events_read.push(events::Event::PendingHTLCsForwardable { + time_forwardable: Duration::from_secs(2), + }); + } + let inbound_pmt_key_material = args.keys_manager.get_inbound_payment_key_material(); let expanded_inbound_key = inbound_payment::ExpandedKey::new(&inbound_pmt_key_material); diff --git a/lightning/src/ln/functional_test_utils.rs b/lightning/src/ln/functional_test_utils.rs index 677fdccfd..bc7f62775 100644 --- a/lightning/src/ln/functional_test_utils.rs +++ b/lightning/src/ln/functional_test_utils.rs @@ -1091,7 +1091,7 @@ macro_rules! check_closed_event { use $crate::util::events::Event; let events = $node.node.get_and_clear_pending_events(); - assert_eq!(events.len(), $events); + assert_eq!(events.len(), $events, "{:?}", events); let expected_reason = $reason; let mut issues_discard_funding = false; for event in events { @@ -1350,7 +1350,7 @@ macro_rules! expect_pending_htlcs_forwardable_conditions { let events = $node.node.get_and_clear_pending_events(); match events[0] { $crate::util::events::Event::PendingHTLCsForwardable { .. } => { }, - _ => panic!("Unexpected event"), + _ => panic!("Unexpected event {:?}", events), }; let count = expected_failures.len() + 1; @@ -1560,7 +1560,7 @@ macro_rules! expect_payment_forwarded { if !$downstream_force_closed { assert!($node.node.list_channels().iter().any(|x| x.counterparty.node_id == $next_node.node.get_our_node_id() && x.channel_id == next_channel_id.unwrap())); } - assert_eq!(claim_from_onchain_tx, $upstream_force_closed); + assert_eq!(claim_from_onchain_tx, $downstream_force_closed); }, _ => panic!("Unexpected event"), } diff --git a/lightning/src/ln/reload_tests.rs b/lightning/src/ln/reload_tests.rs index dc3d53922..7e10f970a 100644 --- a/lightning/src/ln/reload_tests.rs +++ b/lightning/src/ln/reload_tests.rs @@ -10,14 +10,16 @@ //! Functional tests which test for correct behavior across node restarts. use crate::chain::{ChannelMonitorUpdateStatus, Watch}; +use crate::chain::chaininterface::LowerBoundedFeeEstimator; use crate::chain::channelmonitor::ChannelMonitor; +use crate::chain::keysinterface::KeysInterface; use crate::chain::transaction::OutPoint; use crate::ln::channelmanager::{self, ChannelManager, ChannelManagerReadArgs, PaymentId}; use crate::ln::msgs; use crate::ln::msgs::{ChannelMessageHandler, RoutingMessageHandler, ErrorAction}; use crate::util::enforcing_trait_impls::EnforcingSigner; use crate::util::test_utils; -use crate::util::events::{Event, MessageSendEvent, MessageSendEventsProvider, ClosureReason}; +use crate::util::events::{ClosureReason, Event, HTLCDestination, MessageSendEvent, MessageSendEventsProvider}; use crate::util::ser::{Writeable, ReadableArgs}; use crate::util::config::UserConfig; @@ -811,3 +813,123 @@ fn test_partial_claim_before_restart() { do_test_partial_claim_before_restart(false); do_test_partial_claim_before_restart(true); } + +fn do_forwarded_payment_no_manager_persistence(use_cs_commitment: bool, claim_htlc: bool) { + if !use_cs_commitment { assert!(!claim_htlc); } + // If we go to forward a payment, and the ChannelMonitor persistence completes, but the + // ChannelManager does not, we shouldn't try to forward the payment again, nor should we fail + // it back until the ChannelMonitor decides the fate of the HTLC. + // This was never an issue, but it may be easy to regress here going forward. + let chanmon_cfgs = create_chanmon_cfgs(3); + let node_cfgs = create_node_cfgs(3, &chanmon_cfgs); + let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]); + + let persister; + let new_chain_monitor; + let nodes_1_deserialized; + + let mut nodes = create_network(3, &node_cfgs, &node_chanmgrs); + + let chan_id_1 = create_announced_chan_between_nodes(&nodes, 0, 1, channelmanager::provided_init_features(), channelmanager::provided_init_features()).2; + let chan_id_2 = create_announced_chan_between_nodes(&nodes, 1, 2, channelmanager::provided_init_features(), channelmanager::provided_init_features()).2; + + let (route, payment_hash, payment_preimage, payment_secret) = get_route_and_payment_hash!(nodes[0], nodes[2], 1_000_000); + let payment_id = PaymentId(nodes[0].keys_manager.backing.get_secure_random_bytes()); + let htlc_expiry = nodes[0].best_block_info().1 + TEST_FINAL_CLTV; + nodes[0].node.send_payment(&route, payment_hash, &Some(payment_secret), payment_id).unwrap(); + check_added_monitors!(nodes[0], 1); + + let payment_event = SendEvent::from_node(&nodes[0]); + nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &payment_event.msgs[0]); + commitment_signed_dance!(nodes[1], nodes[0], payment_event.commitment_msg, false); + + let node_encoded = nodes[1].node.encode(); + + expect_pending_htlcs_forwardable!(nodes[1]); + + let payment_event = SendEvent::from_node(&nodes[1]); + nodes[2].node.handle_update_add_htlc(&nodes[1].node.get_our_node_id(), &payment_event.msgs[0]); + nodes[2].node.handle_commitment_signed(&nodes[1].node.get_our_node_id(), &payment_event.commitment_msg); + check_added_monitors!(nodes[2], 1); + + if claim_htlc { + get_monitor!(nodes[2], chan_id_2).provide_payment_preimage(&payment_hash, &payment_preimage, + &nodes[2].tx_broadcaster, &LowerBoundedFeeEstimator(nodes[2].fee_estimator), &nodes[2].logger); + } + assert!(nodes[2].tx_broadcaster.txn_broadcasted.lock().unwrap().is_empty()); + + let _ = nodes[2].node.get_and_clear_pending_msg_events(); + + nodes[2].node.force_close_broadcasting_latest_txn(&chan_id_2, &nodes[1].node.get_our_node_id()).unwrap(); + let cs_commitment_tx = nodes[2].tx_broadcaster.txn_broadcasted.lock().unwrap().split_off(0); + assert_eq!(cs_commitment_tx.len(), if claim_htlc { 2 } else { 1 }); + + check_added_monitors!(nodes[2], 1); + check_closed_event!(nodes[2], 1, ClosureReason::HolderForceClosed); + check_closed_broadcast!(nodes[2], true); + + let chan_0_monitor_serialized = get_monitor!(nodes[1], chan_id_1).encode(); + let chan_1_monitor_serialized = get_monitor!(nodes[1], chan_id_2).encode(); + reload_node!(nodes[1], node_encoded, &[&chan_0_monitor_serialized, &chan_1_monitor_serialized], persister, new_chain_monitor, nodes_1_deserialized); + + check_closed_event!(nodes[1], 1, ClosureReason::OutdatedChannelManager); + + let bs_commitment_tx = nodes[1].tx_broadcaster.txn_broadcasted.lock().unwrap().split_off(0); + assert_eq!(bs_commitment_tx.len(), 1); + + nodes[0].node.peer_disconnected(&nodes[1].node.get_our_node_id(), true); + reconnect_nodes(&nodes[0], &nodes[1], (false, false), (0, 0), (0, 0), (0, 0), (0, 0), (0, 0), (false, false)); + + if use_cs_commitment { + // If we confirm a commitment transaction that has the HTLC on-chain, nodes[1] should wait + // for an HTLC-spending transaction before it does anything with the HTLC upstream. + confirm_transaction(&nodes[1], &cs_commitment_tx[0]); + assert!(nodes[1].node.get_and_clear_pending_events().is_empty()); + assert!(nodes[1].node.get_and_clear_pending_msg_events().is_empty()); + + if claim_htlc { + confirm_transaction(&nodes[1], &cs_commitment_tx[1]); + } else { + connect_blocks(&nodes[1], htlc_expiry - nodes[1].best_block_info().1); + let bs_htlc_timeout_tx = nodes[1].tx_broadcaster.txn_broadcasted.lock().unwrap().split_off(0); + assert_eq!(bs_htlc_timeout_tx.len(), 1); + confirm_transaction(&nodes[1], &bs_htlc_timeout_tx[0]); + } + } else { + confirm_transaction(&nodes[1], &bs_commitment_tx[0]); + } + + if !claim_htlc { + expect_pending_htlcs_forwardable_and_htlc_handling_failed!(nodes[1], [HTLCDestination::NextHopChannel { node_id: Some(nodes[2].node.get_our_node_id()), channel_id: chan_id_2 }]); + } else { + expect_payment_forwarded!(nodes[1], nodes[0], nodes[2], Some(1000), false, true); + } + check_added_monitors!(nodes[1], 1); + + let events = nodes[1].node.get_and_clear_pending_msg_events(); + assert_eq!(events.len(), 1); + match &events[0] { + MessageSendEvent::UpdateHTLCs { updates: msgs::CommitmentUpdate { update_fulfill_htlcs, update_fail_htlcs, commitment_signed, .. }, .. } => { + if claim_htlc { + nodes[0].node.handle_update_fulfill_htlc(&nodes[1].node.get_our_node_id(), &update_fulfill_htlcs[0]); + } else { + nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &update_fail_htlcs[0]); + } + commitment_signed_dance!(nodes[0], nodes[1], commitment_signed, false); + }, + _ => panic!("Unexpected event"), + } + + if claim_htlc { + expect_payment_sent!(nodes[0], payment_preimage); + } else { + expect_payment_failed!(nodes[0], payment_hash, false); + } +} + +#[test] +fn forwarded_payment_no_manager_persistence() { + do_forwarded_payment_no_manager_persistence(true, true); + do_forwarded_payment_no_manager_persistence(true, false); + do_forwarded_payment_no_manager_persistence(false, false); +} -- 2.39.5