Merge pull request #2781 from jkczyz/2023-09-multihop-paths
[rust-lightning] / lightning / src / onion_message / messenger.rs
index 05ea7a2853cd6bf6c415bde58c4dea0e32acb999..7743270e257b039301b4eaa9cdab681e242590b3 100644 (file)
@@ -64,9 +64,9 @@ pub(super) const MAX_TIMER_TICKS: usize = 2;
 /// # extern crate bitcoin;
 /// # use bitcoin::hashes::_export::_core::time::Duration;
 /// # use bitcoin::hashes::hex::FromHex;
-/// # use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey};
+/// # use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey, self};
 /// # use lightning::blinded_path::BlindedPath;
-/// # use lightning::sign::KeysManager;
+/// # use lightning::sign::{EntropySource, KeysManager};
 /// # use lightning::ln::peer_handler::IgnoringMessageHandler;
 /// # use lightning::onion_message::{OnionMessageContents, Destination, MessageRouter, OnionMessagePath, OnionMessenger};
 /// # use lightning::util::logger::{Logger, Record};
@@ -87,9 +87,14 @@ pub(super) const MAX_TIMER_TICKS: usize = 2;
 /// #         Ok(OnionMessagePath {
 /// #             intermediate_nodes: vec![hop_node_id1, hop_node_id2],
 /// #             destination,
-/// #             addresses: None,
+/// #             first_node_addresses: None,
 /// #         })
 /// #     }
+/// #     fn create_blinded_paths<ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
+/// #         &self, _recipient: PublicKey, _peers: Vec<PublicKey>, _entropy_source: &ES, _secp_ctx: &Secp256k1<T>
+/// #     ) -> Result<Vec<BlindedPath>, ()> {
+/// #         unreachable!()
+/// #     }
 /// # }
 /// # let seed = [42u8; 32];
 /// # let time = Duration::from_secs(123456);
@@ -223,6 +228,13 @@ impl OnionMessageRecipient {
                        *self = OnionMessageRecipient::ConnectedPeer(new_pending_messages);
                }
        }
+
+       fn is_connected(&self) -> bool {
+               match self {
+                       OnionMessageRecipient::ConnectedPeer(..) => true,
+                       OnionMessageRecipient::PendingConnection(..) => false,
+               }
+       }
 }
 
 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
@@ -263,6 +275,15 @@ pub trait MessageRouter {
        fn find_path(
                &self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
        ) -> Result<OnionMessagePath, ()>;
+
+       /// Creates [`BlindedPath`]s to the `recipient` node. The nodes in `peers` are assumed to be
+       /// direct peers with the `recipient`.
+       fn create_blinded_paths<
+               ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification
+       >(
+               &self, recipient: PublicKey, peers: Vec<PublicKey>, entropy_source: &ES,
+               secp_ctx: &Secp256k1<T>
+       ) -> Result<Vec<BlindedPath>, ()>;
 }
 
 /// A [`MessageRouter`] that can only route to a directly connected [`Destination`].
@@ -292,7 +313,9 @@ where
        ) -> Result<OnionMessagePath, ()> {
                let first_node = destination.first_node();
                if peers.contains(&first_node) {
-                       Ok(OnionMessagePath { intermediate_nodes: vec![], destination, addresses: None })
+                       Ok(OnionMessagePath {
+                               intermediate_nodes: vec![], destination, first_node_addresses: None
+                       })
                } else {
                        let network_graph = self.network_graph.deref().read_only();
                        let node_announcement = network_graph
@@ -303,13 +326,56 @@ where
 
                        match node_announcement {
                                Some(node_announcement) if node_announcement.features.supports_onion_messages() => {
-                                       let addresses = Some(node_announcement.addresses.clone());
-                                       Ok(OnionMessagePath { intermediate_nodes: vec![], destination, addresses })
+                                       let first_node_addresses = Some(node_announcement.addresses.clone());
+                                       Ok(OnionMessagePath {
+                                               intermediate_nodes: vec![], destination, first_node_addresses
+                                       })
                                },
                                _ => Err(()),
                        }
                }
        }
+
+       fn create_blinded_paths<
+               ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification
+       >(
+               &self, recipient: PublicKey, peers: Vec<PublicKey>, entropy_source: &ES,
+               secp_ctx: &Secp256k1<T>
+       ) -> Result<Vec<BlindedPath>, ()> {
+               // Limit the number of blinded paths that are computed.
+               const MAX_PATHS: usize = 3;
+
+               // Ensure peers have at least three channels so that it is more difficult to infer the
+               // recipient's node_id.
+               const MIN_PEER_CHANNELS: usize = 3;
+
+               let network_graph = self.network_graph.deref().read_only();
+               let paths = peers.iter()
+                       // Limit to peers with announced channels
+                       .filter(|pubkey|
+                               network_graph
+                                       .node(&NodeId::from_pubkey(pubkey))
+                                       .map(|info| &info.channels[..])
+                                       .map(|channels| channels.len() >= MIN_PEER_CHANNELS)
+                                       .unwrap_or(false)
+                       )
+                       .map(|pubkey| vec![*pubkey, recipient])
+                       .map(|node_pks| BlindedPath::new_for_message(&node_pks, entropy_source, secp_ctx))
+                       .take(MAX_PATHS)
+                       .collect::<Result<Vec<_>, _>>();
+
+               match paths {
+                       Ok(paths) if !paths.is_empty() => Ok(paths),
+                       _ => {
+                               if network_graph.nodes().contains_key(&NodeId::from_pubkey(&recipient)) {
+                                       BlindedPath::one_hop_for_message(recipient, entropy_source, secp_ctx)
+                                               .map(|path| vec![path])
+                               } else {
+                                       Err(())
+                               }
+                       },
+               }
+       }
 }
 
 /// A path for sending an [`OnionMessage`].
@@ -325,7 +391,7 @@ pub struct OnionMessagePath {
        ///
        /// Only needs to be set if a connection to the node is required. [`OnionMessenger`] may use
        /// this to initiate such a connection.
-       pub addresses: Option<Vec<SocketAddress>>,
+       pub first_node_addresses: Option<Vec<SocketAddress>>,
 }
 
 impl OnionMessagePath {
@@ -459,7 +525,8 @@ pub enum PeeledOnion<T: OnionMessageContents> {
 /// Creates an [`OnionMessage`] with the given `contents` for sending to the destination of
 /// `path`.
 ///
-/// Returns both the node id of the peer to send the message to and the message itself.
+/// Returns the node id of the peer to send the message to, the message itself, and any addresses
+/// need to connect to the first node.
 pub fn create_onion_message<ES: Deref, NS: Deref, T: OnionMessageContents>(
        entropy_source: &ES, node_signer: &NS, secp_ctx: &Secp256k1<secp256k1::All>,
        path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
@@ -468,7 +535,7 @@ where
        ES::Target: EntropySource,
        NS::Target: NodeSigner,
 {
-       let OnionMessagePath { intermediate_nodes, mut destination, addresses } = path;
+       let OnionMessagePath { intermediate_nodes, mut destination, first_node_addresses } = path;
        if let Destination::BlindedPath(BlindedPath { ref blinded_hops, .. }) = destination {
                if blinded_hops.is_empty() {
                        return Err(SendError::TooFewBlindedHops);
@@ -510,7 +577,7 @@ where
                packet_payloads, packet_keys, prng_seed).map_err(|()| SendError::TooBigPacket)?;
 
        let message = OnionMessage { blinding_point, onion_routing_packet };
-       Ok((first_node_id, message, addresses))
+       Ok((first_node_id, message, first_node_addresses))
 }
 
 /// Decode one layer of an incoming [`OnionMessage`].
@@ -724,7 +791,11 @@ where
                        },
                        hash_map::Entry::Occupied(mut e) => {
                                e.get_mut().enqueue_message(onion_message);
-                               Ok(SendSuccess::Buffered)
+                               if e.get().is_connected() {
+                                       Ok(SendSuccess::Buffered)
+                               } else {
+                                       Ok(SendSuccess::BufferedAwaitingConnection(first_node_id))
+                               }
                        },
                }
        }
@@ -898,7 +969,8 @@ where
        fn peer_disconnected(&self, their_node_id: &PublicKey) {
                match self.message_recipients.lock().unwrap().remove(their_node_id) {
                        Some(OnionMessageRecipient::ConnectedPeer(..)) => {},
-                       _ => debug_assert!(false),
+                       Some(_) => debug_assert!(false),
+                       None => {},
                }
        }