diff --git a/lightning/src/events/mod.rs b/lightning/src/events/mod.rs index 418f8d5459a..7da0470bdf0 100644 --- a/lightning/src/events/mod.rs +++ b/lightning/src/events/mod.rs @@ -1501,6 +1501,7 @@ impl MaybeReadable for Event { /// broadcast to most peers). /// These events are handled by PeerManager::process_events if you are using a PeerManager. #[derive(Clone, Debug)] +#[cfg_attr(test, derive(PartialEq))] pub enum MessageSendEvent { /// Used to indicate that we've accepted a channel open and should send the accept_channel /// message provided to the given peer. diff --git a/lightning/src/ln/channel.rs b/lightning/src/ln/channel.rs index d5cefc94361..9ab152f5d77 100644 --- a/lightning/src/ln/channel.rs +++ b/lightning/src/ln/channel.rs @@ -3811,6 +3811,17 @@ impl Channel { } } + /// Gets the `Shutdown` message we should send our peer on reconnect, if any. + pub fn get_outbound_shutdown(&self) -> Option { + if self.context.channel_state & (ChannelState::LocalShutdownSent as u32) != 0 { + assert!(self.context.shutdown_scriptpubkey.is_some()); + Some(msgs::Shutdown { + channel_id: self.context.channel_id, + scriptpubkey: self.get_closing_scriptpubkey(), + }) + } else { None } + } + /// May panic if some calls other than message-handling calls (which will all Err immediately) /// have been called between remove_uncommitted_htlcs_and_mark_paused and this call. /// @@ -3877,13 +3888,7 @@ impl Channel { self.context.channel_state &= !(ChannelState::PeerDisconnected as u32); self.context.sent_message_awaiting_response = None; - let shutdown_msg = if self.context.channel_state & (ChannelState::LocalShutdownSent as u32) != 0 { - assert!(self.context.shutdown_scriptpubkey.is_some()); - Some(msgs::Shutdown { - channel_id: self.context.channel_id, - scriptpubkey: self.get_closing_scriptpubkey(), - }) - } else { None }; + let shutdown_msg = self.get_outbound_shutdown(); let announcement_sigs = self.get_announcement_sigs(node_signer, genesis_block_hash, user_config, best_block.height(), logger); diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs index 45fffd5407c..15f536789bf 100644 --- a/lightning/src/ln/channelmanager.rs +++ b/lightning/src/ln/channelmanager.rs @@ -7489,6 +7489,46 @@ where fn handle_error(&self, counterparty_node_id: &PublicKey, msg: &msgs::ErrorMessage) { let _persistence_guard = PersistenceNotifierGuard::notify_on_drop(self); + match &msg.data as &str { + "cannot co-op close channel w/ active htlcs"| + "link failed to shutdown" => + { + // LND hasn't properly handled shutdown messages ever, and force-closes any time we + // send one while HTLCs are still present. The issue is tracked at + // https://github.com/lightningnetwork/lnd/issues/6039 and has had multiple patches + // to fix it but none so far have managed to land upstream. The issue appears to be + // very low priority for the LND team despite being marked "P1". + // We're not going to bother handling this in a sensible way, instead simply + // repeating the Shutdown message on repeat until morale improves. + if msg.channel_id != [0; 32] { + let per_peer_state = self.per_peer_state.read().unwrap(); + let peer_state_mutex_opt = per_peer_state.get(counterparty_node_id); + if peer_state_mutex_opt.is_none() { return; } + let mut peer_state = peer_state_mutex_opt.unwrap().lock().unwrap(); + if let Some(chan) = peer_state.channel_by_id.get(&msg.channel_id) { + if let Some(msg) = chan.get_outbound_shutdown() { + peer_state.pending_msg_events.push(events::MessageSendEvent::SendShutdown { + node_id: *counterparty_node_id, + msg, + }); + } + peer_state.pending_msg_events.push(events::MessageSendEvent::HandleError { + node_id: *counterparty_node_id, + action: msgs::ErrorAction::SendWarningMessage { + msg: msgs::WarningMessage { + channel_id: msg.channel_id, + data: "You appear to be exhibiting LND bug 6039, we'll keep sending you shutdown messages until you handle them correctly".to_owned() + }, + log_level: Level::Trace, + } + }); + } + } + return; + } + _ => {} + } + if msg.channel_id == [0; 32] { let channel_ids: Vec<[u8; 32]> = { let per_peer_state = self.per_peer_state.read().unwrap(); diff --git a/lightning/src/ln/msgs.rs b/lightning/src/ln/msgs.rs index 515dcbba2d2..dc8d9215438 100644 --- a/lightning/src/ln/msgs.rs +++ b/lightning/src/ln/msgs.rs @@ -1144,7 +1144,7 @@ enum EncodingType { } /// Used to put an error message in a [`LightningError`]. -#[derive(Clone, Debug)] +#[derive(Clone, Debug, PartialEq)] pub enum ErrorAction { /// The peer took some action which made us think they were useless. Disconnect them. DisconnectPeer { diff --git a/lightning/src/ln/shutdown_tests.rs b/lightning/src/ln/shutdown_tests.rs index bd4df0af082..5335ab65141 100644 --- a/lightning/src/ln/shutdown_tests.rs +++ b/lightning/src/ln/shutdown_tests.rs @@ -198,6 +198,61 @@ fn expect_channel_shutdown_state_with_htlc() { assert!(nodes[0].node.list_channels().is_empty()); } +#[test] +fn test_lnd_bug_6039() { + // LND sends a nonsense error message any time it gets a shutdown if there are still HTLCs + // pending. We currently swallow that error to work around LND's bug #6039. This test emulates + // the LND nonsense and ensures we at least kinda handle it. + 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 mut nodes = create_network(2, &node_cfgs, &node_chanmgrs); + let chan = create_announced_chan_between_nodes(&nodes, 0, 1); + + let (payment_preimage, payment_hash, _) = route_payment(&nodes[0], &[&nodes[1]], 100_000); + + nodes[0].node.close_channel(&chan.2, &nodes[1].node.get_our_node_id()).unwrap(); + let node_0_shutdown = get_event_msg!(nodes[0], MessageSendEvent::SendShutdown, nodes[1].node.get_our_node_id()); + nodes[1].node.handle_shutdown(&nodes[0].node.get_our_node_id(), &node_0_shutdown); + + // Generate an lnd-like error message and check that we respond by simply screaming louder to + // see if LND will accept our protocol compliance. + let err_msg = msgs::ErrorMessage { channel_id: chan.2, data: "link failed to shutdown".to_string() }; + nodes[0].node.handle_error(&nodes[1].node.get_our_node_id(), &err_msg); + let node_a_responses = nodes[0].node.get_and_clear_pending_msg_events(); + assert_eq!(node_a_responses[0], MessageSendEvent::SendShutdown { + node_id: nodes[1].node.get_our_node_id(), + msg: node_0_shutdown, + }); + if let MessageSendEvent::HandleError { action: msgs::ErrorAction::SendWarningMessage { .. }, .. } + = node_a_responses[1] {} else { panic!(); } + + let node_1_shutdown = get_event_msg!(nodes[1], MessageSendEvent::SendShutdown, nodes[0].node.get_our_node_id()); + + assert!(nodes[0].node.get_and_clear_pending_msg_events().is_empty()); + assert!(nodes[1].node.get_and_clear_pending_msg_events().is_empty()); + + claim_payment(&nodes[0], &[&nodes[1]], payment_preimage); + + // Assume that LND will eventually respond to our Shutdown if we clear all the remaining HTLCs + nodes[0].node.handle_shutdown(&nodes[1].node.get_our_node_id(), &node_1_shutdown); + + // ClosingSignNegotion process + let node_0_closing_signed = get_event_msg!(nodes[0], MessageSendEvent::SendClosingSigned, nodes[1].node.get_our_node_id()); + nodes[1].node.handle_closing_signed(&nodes[0].node.get_our_node_id(), &node_0_closing_signed); + let node_1_closing_signed = get_event_msg!(nodes[1], MessageSendEvent::SendClosingSigned, nodes[0].node.get_our_node_id()); + nodes[0].node.handle_closing_signed(&nodes[1].node.get_our_node_id(), &node_1_closing_signed); + let (_, node_0_2nd_closing_signed) = get_closing_signed_broadcast!(nodes[0].node, nodes[1].node.get_our_node_id()); + nodes[1].node.handle_closing_signed(&nodes[0].node.get_our_node_id(), &node_0_2nd_closing_signed.unwrap()); + let (_, node_1_none) = get_closing_signed_broadcast!(nodes[1].node, nodes[0].node.get_our_node_id()); + assert!(node_1_none.is_none()); + check_closed_event!(nodes[0], 1, ClosureReason::CooperativeClosure, [nodes[1].node.get_our_node_id()], 100000); + check_closed_event!(nodes[1], 1, ClosureReason::CooperativeClosure, [nodes[0].node.get_our_node_id()], 100000); + + // Shutdown basically removes the channelDetails, testing of shutdowncomplete state unnecessary + assert!(nodes[0].node.list_channels().is_empty()); +} + #[test] fn expect_channel_shutdown_state_with_force_closure() { // Test sending a shutdown prior to channel_ready after funding generation