Prefer one-hop blinded path to Tor intro nodes

If a node is announced, prefer using a one-hop blinded path with it as
the introduction node to using a two-hop blinded path with a Tor-only
introduction node. The one-hop blinded path is more reliable, thus only
use Tor-only nodes if the recipient is unannounced. And then, prefer
non-Tor-only nodes.

diff --git a/lightning/src/ln/offers_tests.rs b/lightning/src/ln/offers_tests.rs
index 6af4cb6b17faa32c926e4dd81866ab5552fe6ce0..e16c0ed515f5836195d867fed906ea203e763007 100644 (file)
--- a/lightning/src/ln/offers_tests.rs
+++ b/lightning/src/ln/offers_tests.rs
@@ -250,7 +250,7 @@ fn prefers_non_tor_nodes_in_blinded_paths() {
        disconnect_peers(david, &[bob, &nodes[4], &nodes[5]]);
 
        let tor = SocketAddress::OnionV2([255, 254, 253, 252, 251, 250, 249, 248, 247, 246, 38, 7]);
-       announce_node_address(charlie, &[alice, bob, david, &nodes[4], &nodes[5]], tor);
+       announce_node_address(charlie, &[alice, bob, david, &nodes[4], &nodes[5]], tor.clone());
 
        let offer = bob.node
                .create_offer_builder("coffee".to_string()).unwrap()
@@ -259,8 +259,23 @@ fn prefers_non_tor_nodes_in_blinded_paths() {
        assert_ne!(offer.signing_pubkey(), bob_id);
        assert!(!offer.paths().is_empty());
        for path in offer.paths() {
+               assert_ne!(path.introduction_node_id, bob_id);
                assert_ne!(path.introduction_node_id, charlie_id);
        }
+
+       // Use a one-hop blinded path when Bob is announced and all his peers are Tor-only.
+       announce_node_address(&nodes[4], &[alice, bob, charlie, david, &nodes[5]], tor.clone());
+       announce_node_address(&nodes[5], &[alice, bob, charlie, david, &nodes[4]], tor.clone());
+
+       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, bob_id);
+       }
 }
 
 /// Checks that blinded paths prefer an introduction node that is the most connected.

diff --git a/lightning/src/onion_message/messenger.rs b/lightning/src/onion_message/messenger.rs
index 6987ece9627b9856b149a3d0ea8b137436fe4fe2..37de550453283e4a383051ace821cabb44f95ff1 100644 (file)
--- a/lightning/src/onion_message/messenger.rs
+++ b/lightning/src/onion_message/messenger.rs
@@ -358,6 +358,9 @@ where
                const MIN_PEER_CHANNELS: usize = 3;
 
                let network_graph = self.network_graph.deref().read_only();
+               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_map(|pubkey|
@@ -366,6 +369,8 @@ where
                                        .filter(|info| info.channels.len() >= MIN_PEER_CHANNELS)
                                        .map(|info| (*pubkey, info.is_tor_only(), info.channels.len()))
                        )
+                       // 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.
@@ -382,7 +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 {