Merge pull request #3132 from jkczyz/2024-06-bolt12-unannounced

[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 0fb72c52d2784a03973bfb3ac2bbf846fc3daba6..859c3f2b5b9c88fd6e7c42c23698d1402dcbee61 100644 (file)
--- a/lightning/src/onion_message/messenger.rs
+++ b/lightning/src/onion_message/messenger.rs
@@ -489,7 +489,7 @@ where
        }
 
        fn create_blinded_paths_from_iter<
-               I: Iterator<Item = ForwardNode>,
+               I: ExactSizeIterator<Item = ForwardNode>,
                T: secp256k1::Signing + secp256k1::Verification
        >(
                &self, recipient: PublicKey, peers: I, secp_ctx: &Secp256k1<T>, compact_paths: bool
@@ -505,13 +505,20 @@ where
                let is_recipient_announced =
                        network_graph.nodes().contains_key(&NodeId::from_pubkey(&recipient));
 
+               let has_one_peer = peers.len() == 1;
                let mut peer_info = peers
-                       // Limit to peers with announced channels
+                       // Limit to peers with announced channels unless the recipient is unannounced.
                        .filter_map(|peer|
                                network_graph
                                        .node(&NodeId::from_pubkey(&peer.node_id))
-                                       .filter(|info| info.channels.len() >= MIN_PEER_CHANNELS)
+                                       .filter(|info|
+                                               !is_recipient_announced || info.channels.len() >= MIN_PEER_CHANNELS
+                                       )
                                        .map(|info| (peer, info.is_tor_only(), info.channels.len()))
+                                       // Allow messages directly with the only peer when unannounced.
+                                       .or_else(|| (!is_recipient_announced && has_one_peer)
+                                               .then(|| (peer, false, 0))
+                                       )
                        )
                        // Exclude Tor-only nodes when the recipient is announced.
                        .filter(|(_, is_tor_only, _)| !(*is_tor_only && is_recipient_announced))