From 3dff4abfb1610862920ea36765424b609887ab2f Mon Sep 17 00:00:00 2001 From: Wilmer Paulino Date: Tue, 14 Jun 2022 16:41:32 -0700 Subject: [PATCH] Expose API to update a channel's ChannelConfig A new `update_channel_config` method is exposed on the `ChannelManger` to update the `ChannelConfig` for a set of channels atomically. New `ChannelUpdate` events are generated for each eligible channel. Note that as currently implemented, a buggy and/or auto-policy-management client could spam the network with updates as there is no rate-limiting in place. This could already be done with `broadcast_node_announcement`, though users are less inclined to update that as frequently as its data is mostly static. --- lightning/src/ln/channel.rs | 17 ++- lightning/src/ln/channelmanager.rs | 67 +++++++++ lightning/src/ln/onion_route_tests.rs | 188 +++++++++++++++++++++++++- 3 files changed, 265 insertions(+), 7 deletions(-) diff --git a/lightning/src/ln/channel.rs b/lightning/src/ln/channel.rs index 846bfd01..ab26cea3 100644 --- a/lightning/src/ln/channel.rs +++ b/lightning/src/ln/channel.rs @@ -4491,12 +4491,27 @@ impl Channel { self.config.options.max_dust_htlc_exposure_msat } - /// Returns the current [`ChannelConfig`] applied to the channel. pub fn config(&self) -> ChannelConfig { self.config.options } + /// Updates the channel's config. A bool is returned indicating whether the config update + /// applied resulted in a new ChannelUpdate message. + pub fn update_config(&mut self, config: &ChannelConfig) -> bool { + let did_channel_update = + self.config.options.forwarding_fee_proportional_millionths != config.forwarding_fee_proportional_millionths || + self.config.options.forwarding_fee_base_msat != config.forwarding_fee_base_msat || + self.config.options.cltv_expiry_delta != config.cltv_expiry_delta; + if did_channel_update { + // Update the counter, which backs the ChannelUpdate timestamp, to allow the relay + // policy change to propagate throughout the network. + self.update_time_counter += 1; + } + self.config.options = *config; + did_channel_update + } + pub fn get_feerate(&self) -> u32 { self.feerate_per_kw } diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs index 6913e1f7..58d84eb0 100644 --- a/lightning/src/ln/channelmanager.rs +++ b/lightning/src/ln/channelmanager.rs @@ -2919,6 +2919,73 @@ impl ChannelMana } } + /// Atomically updates the [`ChannelConfig`] for the given channels. + /// + /// Once the updates are applied, each eligible channel (advertised with a known short channel + /// ID and a change in [`forwarding_fee_proportional_millionths`], [`forwarding_fee_base_msat`], + /// or [`cltv_expiry_delta`]) has a [`BroadcastChannelUpdate`] event message generated + /// containing the new [`ChannelUpdate`] message which should be broadcast to the network. + /// + /// Returns [`ChannelUnavailable`] when a channel is not found or an incorrect + /// `counterparty_node_id` is provided. + /// + /// Returns [`APIMisuseError`] when a [`cltv_expiry_delta`] update is to be applied with a value + /// below [`MIN_CLTV_EXPIRY_DELTA`]. + /// + /// If an error is returned, none of the updates should be considered applied. + /// + /// [`forwarding_fee_proportional_millionths`]: ChannelConfig::forwarding_fee_proportional_millionths + /// [`forwarding_fee_base_msat`]: ChannelConfig::forwarding_fee_base_msat + /// [`cltv_expiry_delta`]: ChannelConfig::cltv_expiry_delta + /// [`BroadcastChannelUpdate`]: events::MessageSendEvent::BroadcastChannelUpdate + /// [`ChannelUpdate`]: msgs::ChannelUpdate + /// [`ChannelUnavailable`]: APIError::ChannelUnavailable + /// [`APIMisuseError`]: APIError::APIMisuseError + pub fn update_channel_config( + &self, counterparty_node_id: &PublicKey, channel_ids: &[[u8; 32]], config: &ChannelConfig, + ) -> Result<(), APIError> { + if config.cltv_expiry_delta < MIN_CLTV_EXPIRY_DELTA { + return Err(APIError::APIMisuseError { + err: format!("The chosen CLTV expiry delta is below the minimum of {}", MIN_CLTV_EXPIRY_DELTA), + }); + } + + let _persistence_guard = PersistenceNotifierGuard::notify_on_drop( + &self.total_consistency_lock, &self.persistence_notifier, + ); + { + let mut channel_state_lock = self.channel_state.lock().unwrap(); + let channel_state = &mut *channel_state_lock; + for channel_id in channel_ids { + let channel_counterparty_node_id = channel_state.by_id.get(channel_id) + .ok_or(APIError::ChannelUnavailable { + err: format!("Channel with ID {} was not found", log_bytes!(*channel_id)), + })? + .get_counterparty_node_id(); + if channel_counterparty_node_id != *counterparty_node_id { + return Err(APIError::APIMisuseError { + err: "counterparty node id mismatch".to_owned(), + }); + } + } + for channel_id in channel_ids { + let channel = channel_state.by_id.get_mut(channel_id).unwrap(); + if !channel.update_config(config) { + continue; + } + if let Ok(msg) = self.get_channel_update_for_broadcast(channel) { + channel_state.pending_msg_events.push(events::MessageSendEvent::BroadcastChannelUpdate { msg }); + } else if let Ok(msg) = self.get_channel_update_for_unicast(channel) { + channel_state.pending_msg_events.push(events::MessageSendEvent::SendChannelUpdate { + node_id: channel.get_counterparty_node_id(), + msg, + }); + } + } + } + Ok(()) + } + /// Processes HTLCs which are pending waiting on random forward delay. /// /// Should only really ever be called in response to a PendingHTLCsForwardable event. diff --git a/lightning/src/ln/onion_route_tests.rs b/lightning/src/ln/onion_route_tests.rs index 1e340d4a..27c701bc 100644 --- a/lightning/src/ln/onion_route_tests.rs +++ b/lightning/src/ln/onion_route_tests.rs @@ -11,10 +11,10 @@ //! These tests work by standing up full nodes and route payments across the network, checking the //! returned errors decode to the correct thing. -use chain::channelmonitor::{CLTV_CLAIM_BUFFER, LATENCY_GRACE_PERIOD_BLOCKS}; +use chain::channelmonitor::{ChannelMonitor, CLTV_CLAIM_BUFFER, LATENCY_GRACE_PERIOD_BLOCKS}; use chain::keysinterface::{KeysInterface, Recipient}; use ln::{PaymentHash, PaymentSecret}; -use ln::channelmanager::{HTLCForwardInfo, CLTV_FAR_FAR_AWAY, MIN_CLTV_EXPIRY_DELTA, PendingHTLCInfo, PendingHTLCRouting}; +use ln::channelmanager::{ChannelManager, ChannelManagerReadArgs, HTLCForwardInfo, CLTV_FAR_FAR_AWAY, MIN_CLTV_EXPIRY_DELTA, PendingHTLCInfo, PendingHTLCRouting}; use ln::onion_utils; use routing::gossip::{NetworkUpdate, RoutingFees, NodeId}; use routing::router::{get_route, PaymentParameters, Route, RouteHint, RouteHintHop}; @@ -23,9 +23,10 @@ use ln::msgs; use ln::msgs::{ChannelMessageHandler, ChannelUpdate, OptionalField}; use ln::wire::Encode; use util::events::{Event, MessageSendEvent, MessageSendEventsProvider}; -use util::ser::{Writeable, Writer}; +use util::ser::{ReadableArgs, Writeable, Writer}; use util::{byte_utils, test_utils}; -use util::config::UserConfig; +use util::config::{UserConfig, ChannelConfig}; +use util::errors::APIError; use bitcoin::hash_types::BlockHash; @@ -506,8 +507,6 @@ fn test_onion_failure() { let preimage = send_along_route(&nodes[0], bogus_route, &[&nodes[1], &nodes[2]], amt_to_forward+1).0; claim_payment(&nodes[0], &[&nodes[1], &nodes[2]], preimage); - //TODO: with new config API, we will be able to generate both valid and - //invalid channel_update cases. let short_channel_id = channels[0].0.contents.short_channel_id; run_onion_failure_test("fee_insufficient", 0, &nodes, &route, &payment_hash, &payment_secret, |msg| { msg.amount_msat -= 1; @@ -594,6 +593,183 @@ fn test_onion_failure() { }, true, Some(23), None, None); } +fn do_test_onion_failure_stale_channel_update(announced_channel: bool) { + // Create a network of three nodes and two channels connecting them. We'll be updating the + // HTLC relay policy of the second channel, causing forwarding failures at the first hop. + let mut config = UserConfig::default(); + config.channel_handshake_config.announced_channel = announced_channel; + config.channel_handshake_limits.force_announced_channel_preference = false; + config.accept_forwards_to_priv_channels = !announced_channel; + 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, Some(config), None]); + let mut nodes = create_network(3, &node_cfgs, &node_chanmgrs); + + let other_channel = create_chan_between_nodes( + &nodes[0], &nodes[1], InitFeatures::known(), InitFeatures::known(), + ); + let channel_to_update = if announced_channel { + let channel = create_announced_chan_between_nodes( + &nodes, 1, 2, InitFeatures::known(), InitFeatures::known(), + ); + (channel.2, channel.0.contents.short_channel_id) + } else { + let channel = create_unannounced_chan_between_nodes_with_value( + &nodes, 1, 2, 100000, 10001, InitFeatures::known(), InitFeatures::known(), + ); + (channel.0.channel_id, channel.0.short_channel_id_alias.unwrap()) + }; + let channel_to_update_counterparty = &nodes[2].node.get_our_node_id(); + + let default_config = ChannelConfig::default(); + + // A test payment should succeed as the ChannelConfig has not been changed yet. + const PAYMENT_AMT: u64 = 40000; + let (route, payment_hash, payment_preimage, payment_secret) = if announced_channel { + get_route_and_payment_hash!(nodes[0], nodes[2], PAYMENT_AMT) + } else { + let hop_hints = vec![RouteHint(vec![RouteHintHop { + src_node_id: nodes[1].node.get_our_node_id(), + short_channel_id: channel_to_update.1, + fees: RoutingFees { + base_msat: default_config.forwarding_fee_base_msat, + proportional_millionths: default_config.forwarding_fee_proportional_millionths, + }, + cltv_expiry_delta: default_config.cltv_expiry_delta, + htlc_maximum_msat: None, + htlc_minimum_msat: None, + }])]; + let payment_params = PaymentParameters::from_node_id(*channel_to_update_counterparty) + .with_features(InvoiceFeatures::known()) + .with_route_hints(hop_hints); + get_route_and_payment_hash!(nodes[0], nodes[2], payment_params, PAYMENT_AMT, TEST_FINAL_CLTV) + }; + send_along_route_with_secret(&nodes[0], route.clone(), &[&[&nodes[1], &nodes[2]]], PAYMENT_AMT, + payment_hash, payment_secret); + claim_payment(&nodes[0], &[&nodes[1], &nodes[2]], payment_preimage); + + // Closure to update and retrieve the latest ChannelUpdate. + let update_and_get_channel_update = |config: &ChannelConfig, expect_new_update: bool, + prev_update: Option<&msgs::ChannelUpdate>| -> Option { + nodes[1].node.update_channel_config( + channel_to_update_counterparty, &[channel_to_update.0], config, + ).unwrap(); + let events = nodes[1].node.get_and_clear_pending_msg_events(); + assert_eq!(events.len(), expect_new_update as usize); + if !expect_new_update { + return None; + } + let new_update = match &events[0] { + MessageSendEvent::BroadcastChannelUpdate { msg } => { + assert!(announced_channel); + msg.clone() + }, + MessageSendEvent::SendChannelUpdate { node_id, msg } => { + assert_eq!(node_id, channel_to_update_counterparty); + assert!(!announced_channel); + msg.clone() + }, + _ => panic!("expected Broadcast/SendChannelUpdate event"), + }; + if prev_update.is_some() { + assert!(new_update.contents.timestamp > prev_update.unwrap().contents.timestamp) + } + Some(new_update) + }; + + // We'll be attempting to route payments using the default ChannelUpdate for channels. This will + // lead to onion failures at the first hop once we update the ChannelConfig for the + // second hop. + let expect_onion_failure = |name: &str, error_code: u16, channel_update: &msgs::ChannelUpdate| { + let short_channel_id = channel_to_update.1; + let network_update = NetworkUpdate::ChannelUpdateMessage { msg: channel_update.clone() }; + run_onion_failure_test( + name, 0, &nodes, &route, &payment_hash, &payment_secret, |_| {}, || {}, true, + Some(error_code), Some(network_update), Some(short_channel_id), + ); + }; + + // Updates to cltv_expiry_delta below MIN_CLTV_EXPIRY_DELTA should fail with APIMisuseError. + let mut invalid_config = default_config.clone(); + invalid_config.cltv_expiry_delta = 0; + match nodes[1].node.update_channel_config( + channel_to_update_counterparty, &[channel_to_update.0], &invalid_config, + ) { + Err(APIError::APIMisuseError{ .. }) => {}, + _ => panic!("unexpected result applying invalid cltv_expiry_delta"), + } + + // Increase the base fee which should trigger a new ChannelUpdate. + let mut config = nodes[1].node.list_usable_channels().iter() + .find(|channel| channel.channel_id == channel_to_update.0).unwrap() + .config.unwrap(); + config.forwarding_fee_base_msat = u32::max_value(); + let msg = update_and_get_channel_update(&config, true, None).unwrap(); + expect_onion_failure("fee_insufficient", UPDATE|12, &msg); + + // Redundant updates should not trigger a new ChannelUpdate. + assert!(update_and_get_channel_update(&config, false, None).is_none()); + + // Similarly, updates that do not have an affect on ChannelUpdate should not trigger a new one. + config.force_close_avoidance_max_fee_satoshis *= 2; + assert!(update_and_get_channel_update(&config, false, None).is_none()); + + // Reset the base fee to the default and increase the proportional fee which should trigger a + // new ChannelUpdate. + config.forwarding_fee_base_msat = default_config.forwarding_fee_base_msat; + config.cltv_expiry_delta = u16::max_value(); + let msg = update_and_get_channel_update(&config, true, Some(&msg)).unwrap(); + expect_onion_failure("incorrect_cltv_expiry", UPDATE|13, &msg); + + // Reset the proportional fee and increase the CLTV expiry delta which should trigger a new + // ChannelUpdate. + config.cltv_expiry_delta = default_config.cltv_expiry_delta; + config.forwarding_fee_proportional_millionths = u32::max_value(); + let msg = update_and_get_channel_update(&config, true, Some(&msg)).unwrap(); + expect_onion_failure("fee_insufficient", UPDATE|12, &msg); + + // To test persistence of the updated config, we'll re-initialize the ChannelManager. + let config_after_restart = { + let persister = test_utils::TestPersister::new(); + let chain_monitor = test_utils::TestChainMonitor::new( + Some(nodes[1].chain_source), nodes[1].tx_broadcaster.clone(), nodes[1].logger, + node_cfgs[1].fee_estimator, &persister, nodes[1].keys_manager, + ); + + let mut chanmon_1 = <(_, ChannelMonitor<_>)>::read( + &mut &get_monitor!(nodes[1], other_channel.3).encode()[..], nodes[1].keys_manager, + ).unwrap().1; + let mut chanmon_2 = <(_, ChannelMonitor<_>)>::read( + &mut &get_monitor!(nodes[1], channel_to_update.0).encode()[..], nodes[1].keys_manager, + ).unwrap().1; + let mut channel_monitors = HashMap::new(); + channel_monitors.insert(chanmon_1.get_funding_txo().0, &mut chanmon_1); + channel_monitors.insert(chanmon_2.get_funding_txo().0, &mut chanmon_2); + + let chanmgr = <(_, ChannelManager<_, _, _, _, _, _>)>::read( + &mut &nodes[1].node.encode()[..], ChannelManagerReadArgs { + default_config: *nodes[1].node.get_current_default_configuration(), + keys_manager: nodes[1].keys_manager, + fee_estimator: node_cfgs[1].fee_estimator, + chain_monitor: &chain_monitor, + tx_broadcaster: nodes[1].tx_broadcaster.clone(), + logger: nodes[1].logger, + channel_monitors: channel_monitors, + }, + ).unwrap().1; + chanmgr.list_channels().iter() + .find(|channel| channel.channel_id == channel_to_update.0).unwrap() + .config.unwrap() + }; + assert_eq!(config, config_after_restart); +} + +#[test] +fn test_onion_failure_stale_channel_update() { + do_test_onion_failure_stale_channel_update(false); + do_test_onion_failure_stale_channel_update(true); +} + #[test] fn test_default_to_onion_payload_tlv_format() { // Tests that we default to creating tlv format onion payloads when no `NodeAnnouncementInfo` -- 2.30.2