Merge pull request #2912 from jkczyz/2024-02-prefer-more-connections

[rust-lightning] / lightning / src / onion_message / messenger.rs

diff --git a/lightning/src/onion_message/messenger.rs b/lightning/src/onion_message/messenger.rs
index 2dc5a89a37b5fae41071d8c4589d813b39916a3e..37de550453283e4a383051ace821cabb44f95ff1 100644 (file)
--- a/lightning/src/onion_message/messenger.rs
+++ b/lightning/src/onion_message/messenger.rs
@@ -358,16 +358,28 @@ where
                const MIN_PEER_CHANNELS: usize = 3;
 
                let network_graph = self.network_graph.deref().read_only();
-               let paths = peers.iter()
+               let is_recipient_announced =
+                       network_graph.nodes().contains_key(&NodeId::from_pubkey(&recipient));
+
+               let mut peer_info = peers.iter()
                        // Limit to peers with announced channels
-                       .filter(|pubkey|
+                       .filter_map(|pubkey|
                                network_graph
                                        .node(&NodeId::from_pubkey(pubkey))
-                                       .map(|info| &info.channels[..])
-                                       .map(|channels| channels.len() >= MIN_PEER_CHANNELS)
-                                       .unwrap_or(false)
+                                       .filter(|info| info.channels.len() >= MIN_PEER_CHANNELS)
+                                       .map(|info| (*pubkey, info.is_tor_only(), info.channels.len()))
                        )
-                       .map(|pubkey| vec![*pubkey, recipient])
+                       // Exclude Tor-only nodes when the recipient is announced.
+                       .filter(|(_, is_tor_only, _)| !(*is_tor_only && is_recipient_announced))
+                       .collect::<Vec<_>>();
+
+               // 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(|node_pks| BlindedPath::new_for_message(&node_pks, &*self.entropy_source, secp_ctx))
                        .take(MAX_PATHS)
                        .collect::<Result<Vec<_>, _>>();
@@ -375,7 +387,7 @@ where
                match paths {
                        Ok(paths) if !paths.is_empty() => Ok(paths),
                        _ => {
-                               if network_graph.nodes().contains_key(&NodeId::from_pubkey(&recipient)) {
+                               if is_recipient_announced {
                                        BlindedPath::one_hop_for_message(recipient, &*self.entropy_source, secp_ctx)
                                                .map(|path| vec![path])
                                } else {