X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fonion_message%2Fmessenger.rs;h=d333eb2103c5ca516217518ab144dab2f84b9807;hb=7d1745e7210975cc0fdc17b31072e33f0dfbf8e3;hp=5ceb0683c57203396da6612a6e2e7835c4c2f8bc;hpb=532617188577150cbd974401b10d2b4e0c2e0809;p=rust-lightning

diff --git a/lightning/src/onion_message/messenger.rs b/lightning/src/onion_message/messenger.rs
index 5ceb0683..d333eb21 100644
--- a/lightning/src/onion_message/messenger.rs
+++ b/lightning/src/onion_message/messenger.rs
@@ -325,12 +325,18 @@ impl OnionMessageRecipient {
 
 /// The `Responder` struct creates an appropriate [`ResponseInstruction`]
 /// for responding to a message.
+#[derive(Clone, Debug, Eq, PartialEq)]
 pub struct Responder {
 	/// The path along which a response can be sent.
 	reply_path: BlindedPath,
 	path_id: Option<[u8; 32]>
 }
 
+impl_writeable_tlv_based!(Responder, {
+	(0, reply_path, required),
+	(2, path_id, option),
+});
+
 impl Responder {
 	/// Creates a new [`Responder`] instance with the provided reply path.
 	pub(super) fn new(reply_path: BlindedPath, path_id: Option<[u8; 32]>) -> Self {
@@ -456,6 +462,13 @@ pub trait MessageRouter {
 }
 
 /// A [`MessageRouter`] that can only route to a directly connected [`Destination`].
+///
+/// # Privacy
+///
+/// Creating [`BlindedPath`]s may affect privacy since, if a suitable path cannot be found, it will
+/// create a one-hop path using the recipient as the introduction node if it is a announced node.
+/// Otherwise, there is no way to find a path to the introduction node in order to send a message,
+/// and thus an `Err` is returned.
 pub struct DefaultMessageRouter<G: Deref<Target=NetworkGraph<L>>, L: Deref, ES: Deref>
 where
 	L::Target: Logger,
@@ -476,7 +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
@@ -492,13 +505,18 @@ 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)
 					.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))