From 5e9a998194ca3f424d96acb0ffbbe9d3fd6b4f76 Mon Sep 17 00:00:00 2001 From: Jeffrey Czyz Date: Wed, 28 Feb 2024 11:23:56 -0600 Subject: [PATCH] Prefer well-connected nodes for introduction nodes When forming blinded paths, using a reliable node as the introduction node is important to ensure onion message reliability. Order blinded paths by how well-connected the introduction node is as a proxy for reliability. For short paths (e.g., when the sender and recipient share an LSP), this may also result in a scenario where initiating a direct connection isn't necessary. That is helpful when using RGS since it currently doesn't include node announcements and thus cannot initiate a direct connection. --- lightning/src/ln/offers_tests.rs | 50 ++++++++++++++++++++++++ lightning/src/onion_message/messenger.rs | 10 +++-- 2 files changed, 57 insertions(+), 3 deletions(-) diff --git a/lightning/src/ln/offers_tests.rs b/lightning/src/ln/offers_tests.rs index 54dc5e4a..6af4cb6b 100644 --- a/lightning/src/ln/offers_tests.rs +++ b/lightning/src/ln/offers_tests.rs @@ -263,6 +263,56 @@ fn prefers_non_tor_nodes_in_blinded_paths() { } } +/// Checks that blinded paths prefer an introduction node that is the most connected. +#[test] +fn prefers_more_connected_nodes_in_blinded_paths() { + let mut accept_forward_cfg = test_default_channel_config(); + accept_forward_cfg.accept_forwards_to_priv_channels = true; + + let mut features = channelmanager::provided_init_features(&accept_forward_cfg); + features.set_onion_messages_optional(); + features.set_route_blinding_optional(); + + let chanmon_cfgs = create_chanmon_cfgs(6); + let node_cfgs = create_node_cfgs(6, &chanmon_cfgs); + + *node_cfgs[1].override_init_features.borrow_mut() = Some(features); + + let node_chanmgrs = create_node_chanmgrs( + 6, &node_cfgs, &[None, Some(accept_forward_cfg), None, None, None, None] + ); + let nodes = create_network(6, &node_cfgs, &node_chanmgrs); + + create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000_000, 1_000_000_000); + create_unannounced_chan_between_nodes_with_value(&nodes, 2, 3, 10_000_000, 1_000_000_000); + create_announced_chan_between_nodes_with_value(&nodes, 1, 2, 10_000_000, 1_000_000_000); + create_announced_chan_between_nodes_with_value(&nodes, 1, 4, 10_000_000, 1_000_000_000); + create_announced_chan_between_nodes_with_value(&nodes, 1, 5, 10_000_000, 1_000_000_000); + create_announced_chan_between_nodes_with_value(&nodes, 2, 4, 10_000_000, 1_000_000_000); + create_announced_chan_between_nodes_with_value(&nodes, 2, 5, 10_000_000, 1_000_000_000); + + // Add extra channels so that more than one of Bob's peers have MIN_PEER_CHANNELS and one has + // more than the others. + create_announced_chan_between_nodes_with_value(&nodes, 0, 4, 10_000_000, 1_000_000_000); + create_announced_chan_between_nodes_with_value(&nodes, 3, 4, 10_000_000, 1_000_000_000); + + let (alice, bob, charlie, david) = (&nodes[0], &nodes[1], &nodes[2], &nodes[3]); + let bob_id = bob.node.get_our_node_id(); + + disconnect_peers(alice, &[charlie, david, &nodes[4], &nodes[5]]); + disconnect_peers(david, &[bob, &nodes[4], &nodes[5]]); + + let offer = bob.node + .create_offer_builder("coffee".to_string()).unwrap() + .amount_msats(10_000_000) + .build().unwrap(); + assert_ne!(offer.signing_pubkey(), bob_id); + assert!(!offer.paths().is_empty()); + for path in offer.paths() { + assert_eq!(path.introduction_node_id, nodes[4].node.get_our_node_id()); + } +} + /// Checks that an offer can be paid through blinded paths and that ephemeral pubkeys are used /// rather than exposing a node's pubkey. #[test] diff --git a/lightning/src/onion_message/messenger.rs b/lightning/src/onion_message/messenger.rs index c221e782..6987ece9 100644 --- a/lightning/src/onion_message/messenger.rs +++ b/lightning/src/onion_message/messenger.rs @@ -364,13 +364,17 @@ where network_graph .node(&NodeId::from_pubkey(pubkey)) .filter(|info| info.channels.len() >= MIN_PEER_CHANNELS) - .map(|info| (*pubkey, info.is_tor_only())) + .map(|info| (*pubkey, info.is_tor_only(), info.channels.len())) ) .collect::>(); - peer_info.sort_unstable_by(|(_, a_tor_only), (_, b_tor_only)| a_tor_only.cmp(b_tor_only)); + + // Prefer using non-Tor nodes with the most channels as the introduction node. + peer_info.sort_unstable_by(|(_, a_tor_only, a_channels), (_, b_tor_only, b_channels)| { + a_tor_only.cmp(b_tor_only).then(a_channels.cmp(b_channels).reverse()) + }); let paths = peer_info.into_iter() - .map(|(pubkey, _)| vec![pubkey, recipient]) + .map(|(pubkey, _, _)| vec![pubkey, recipient]) .map(|node_pks| BlindedPath::new_for_message(&node_pks, &*self.entropy_source, secp_ctx)) .take(MAX_PATHS) .collect::, _>>(); -- 2.30.2