+
+ /// Send an onion message with contents `message` to `destination`, routing it through `intermediate_nodes`.
+ /// See [`OnionMessenger`] for example usage.
+ pub fn send_onion_message<T: CustomOnionMessageContents>(&self, intermediate_nodes: &[PublicKey], mut destination: Destination, message: OnionMessageContents<T>, reply_path: Option<BlindedPath>) -> Result<(), SendError> {
+ if let Destination::BlindedPath(BlindedPath { ref blinded_hops, .. }) = destination {
+ if blinded_hops.len() < 2 {
+ return Err(SendError::TooFewBlindedHops);
+ }
+ }
+ let OnionMessageContents::Custom(ref msg) = message;
+ if msg.tlv_type() < 64 { return Err(SendError::InvalidMessage) }
+
+ // If we are sending straight to a blinded path and we are the introduction node, we need to
+ // advance the blinded path by 1 hop so the second hop is the new introduction node.
+ if intermediate_nodes.len() == 0 {
+ if let Destination::BlindedPath(ref mut blinded_path) = destination {
+ let our_node_id = self.node_signer.get_node_id(Recipient::Node)
+ .map_err(|()| SendError::GetNodeIdFailed)?;
+ if blinded_path.introduction_node_id == our_node_id {
+ blinded_path.advance_by_one(&self.node_signer, &self.secp_ctx)
+ .map_err(|()| SendError::BlindedPathAdvanceFailed)?;
+ }
+ }
+ }
+
+ let blinding_secret_bytes = self.entropy_source.get_secure_random_bytes();
+ let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
+ let (introduction_node_id, blinding_point) = if intermediate_nodes.len() != 0 {
+ (intermediate_nodes[0], PublicKey::from_secret_key(&self.secp_ctx, &blinding_secret))
+ } else {
+ match destination {
+ Destination::Node(pk) => (pk, PublicKey::from_secret_key(&self.secp_ctx, &blinding_secret)),
+ Destination::BlindedPath(BlindedPath { introduction_node_id, blinding_point, .. }) =>
+ (introduction_node_id, blinding_point),
+ }
+ };
+ let (packet_payloads, packet_keys) = packet_payloads_and_keys(
+ &self.secp_ctx, intermediate_nodes, destination, message, reply_path, &blinding_secret)
+ .map_err(|e| SendError::Secp256k1(e))?;
+
+ let prng_seed = self.entropy_source.get_secure_random_bytes();
+ let onion_routing_packet = construct_onion_message_packet(
+ packet_payloads, packet_keys, prng_seed).map_err(|()| SendError::TooBigPacket)?;
+
+ let mut pending_per_peer_msgs = self.pending_messages.lock().unwrap();
+ if outbound_buffer_full(&introduction_node_id, &pending_per_peer_msgs) { return Err(SendError::BufferFull) }
+ match pending_per_peer_msgs.entry(introduction_node_id) {
+ hash_map::Entry::Vacant(_) => Err(SendError::InvalidFirstHop),
+ hash_map::Entry::Occupied(mut e) => {
+ e.get_mut().push_back(msgs::OnionMessage { blinding_point, onion_routing_packet });
+ Ok(())
+ }
+ }
+ }
+
+ #[cfg(test)]
+ pub(super) fn release_pending_msgs(&self) -> HashMap<PublicKey, VecDeque<msgs::OnionMessage>> {
+ let mut pending_msgs = self.pending_messages.lock().unwrap();
+ let mut msgs = HashMap::new();
+ // We don't want to disconnect the peers by removing them entirely from the original map, so we
+ // swap the pending message buffers individually.
+ for (peer_node_id, pending_messages) in &mut *pending_msgs {
+ msgs.insert(*peer_node_id, core::mem::take(pending_messages));
+ }
+ msgs
+ }
+}
+
+fn outbound_buffer_full(peer_node_id: &PublicKey, buffer: &HashMap<PublicKey, VecDeque<msgs::OnionMessage>>) -> bool {
+ const MAX_TOTAL_BUFFER_SIZE: usize = (1 << 20) * 128;
+ const MAX_PER_PEER_BUFFER_SIZE: usize = (1 << 10) * 256;
+ let mut total_buffered_bytes = 0;
+ let mut peer_buffered_bytes = 0;
+ for (pk, peer_buf) in buffer {
+ for om in peer_buf {
+ let om_len = om.serialized_length();
+ if pk == peer_node_id {
+ peer_buffered_bytes += om_len;
+ }
+ total_buffered_bytes += om_len;
+
+ if total_buffered_bytes >= MAX_TOTAL_BUFFER_SIZE ||
+ peer_buffered_bytes >= MAX_PER_PEER_BUFFER_SIZE
+ {
+ return true
+ }
+ }
+ }
+ false
+}
+
+impl<ES: Deref, NS: Deref, L: Deref, CMH: Deref> OnionMessageHandler for OnionMessenger<ES, NS, L, CMH>
+ where ES::Target: EntropySource,
+ NS::Target: NodeSigner,
+ L::Target: Logger,
+ CMH::Target: CustomOnionMessageHandler + Sized,
+{
+ /// Handle an incoming onion message. Currently, if a message was destined for us we will log, but
+ /// soon we'll delegate the onion message to a handler that can generate invoices or send
+ /// payments.
+ fn handle_onion_message(&self, _peer_node_id: &PublicKey, msg: &msgs::OnionMessage) {
+ let control_tlvs_ss = match self.node_signer.ecdh(Recipient::Node, &msg.blinding_point, None) {
+ Ok(ss) => ss,
+ Err(e) => {
+ log_error!(self.logger, "Failed to retrieve node secret: {:?}", e);
+ return
+ }
+ };
+ let onion_decode_ss = {
+ let blinding_factor = {
+ let mut hmac = HmacEngine::<Sha256>::new(b"blinded_node_id");
+ hmac.input(control_tlvs_ss.as_ref());
+ Hmac::from_engine(hmac).into_inner()
+ };
+ match self.node_signer.ecdh(Recipient::Node, &msg.onion_routing_packet.public_key,
+ Some(&Scalar::from_be_bytes(blinding_factor).unwrap()))
+ {
+ Ok(ss) => ss.secret_bytes(),
+ Err(()) => {
+ log_trace!(self.logger, "Failed to compute onion packet shared secret");
+ return
+ }
+ }
+ };
+ match onion_utils::decode_next_untagged_hop(onion_decode_ss, &msg.onion_routing_packet.hop_data[..],
+ msg.onion_routing_packet.hmac, (control_tlvs_ss, &*self.custom_handler))
+ {
+ Ok((Payload::Receive::<<<CMH as Deref>::Target as CustomOnionMessageHandler>::CustomMessage> {
+ message, control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id }), reply_path,
+ }, None)) => {
+ log_info!(self.logger,
+ "Received an onion message with path_id {:02x?} and {} reply_path",
+ path_id, if reply_path.is_some() { "a" } else { "no" });
+ match message {
+ OnionMessageContents::Custom(msg) => self.custom_handler.handle_custom_message(msg),
+ }
+ },
+ Ok((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
+ next_node_id, next_blinding_override
+ })), Some((next_hop_hmac, new_packet_bytes)))) => {
+ // TODO: we need to check whether `next_node_id` is our node, in which case this is a dummy
+ // blinded hop and this onion message is destined for us. In this situation, we should keep
+ // unwrapping the onion layers to get to the final payload. Since we don't have the option
+ // of creating blinded paths with dummy hops currently, we should be ok to not handle this
+ // for now.
+ let new_pubkey = match onion_utils::next_hop_packet_pubkey(&self.secp_ctx, msg.onion_routing_packet.public_key, &onion_decode_ss) {
+ Ok(pk) => pk,
+ Err(e) => {
+ log_trace!(self.logger, "Failed to compute next hop packet pubkey: {}", e);
+ return
+ }
+ };
+ let outgoing_packet = Packet {
+ version: 0,
+ public_key: new_pubkey,
+ hop_data: new_packet_bytes,
+ hmac: next_hop_hmac,
+ };
+ let onion_message = msgs::OnionMessage {
+ blinding_point: match next_blinding_override {
+ Some(blinding_point) => blinding_point,
+ None => {
+ let blinding_factor = {
+ let mut sha = Sha256::engine();
+ sha.input(&msg.blinding_point.serialize()[..]);
+ sha.input(control_tlvs_ss.as_ref());
+ Sha256::from_engine(sha).into_inner()
+ };
+ let next_blinding_point = msg.blinding_point;
+ match next_blinding_point.mul_tweak(&self.secp_ctx, &Scalar::from_be_bytes(blinding_factor).unwrap()) {
+ Ok(bp) => bp,
+ Err(e) => {
+ log_trace!(self.logger, "Failed to compute next blinding point: {}", e);
+ return
+ }
+ }
+ },
+ },
+ onion_routing_packet: outgoing_packet,
+ };
+
+ let mut pending_per_peer_msgs = self.pending_messages.lock().unwrap();
+ if outbound_buffer_full(&next_node_id, &pending_per_peer_msgs) {
+ log_trace!(self.logger, "Dropping forwarded onion message to peer {:?}: outbound buffer full", next_node_id);
+ return
+ }
+
+ #[cfg(fuzzing)]
+ pending_per_peer_msgs.entry(next_node_id).or_insert_with(VecDeque::new);
+
+ match pending_per_peer_msgs.entry(next_node_id) {
+ hash_map::Entry::Vacant(_) => {
+ log_trace!(self.logger, "Dropping forwarded onion message to disconnected peer {:?}", next_node_id);
+ return
+ },
+ hash_map::Entry::Occupied(mut e) => {
+ e.get_mut().push_back(onion_message);
+ log_trace!(self.logger, "Forwarding an onion message to peer {}", next_node_id);
+ }
+ };
+ },
+ Err(e) => {
+ log_trace!(self.logger, "Errored decoding onion message packet: {:?}", e);
+ },
+ _ => {
+ log_trace!(self.logger, "Received bogus onion message packet, either the sender encoded a final hop as a forwarding hop or vice versa");
+ },
+ };
+ }
+
+ fn peer_connected(&self, their_node_id: &PublicKey, init: &msgs::Init, _inbound: bool) -> Result<(), ()> {
+ if init.features.supports_onion_messages() {
+ let mut peers = self.pending_messages.lock().unwrap();
+ peers.insert(their_node_id.clone(), VecDeque::new());
+ }
+ Ok(())
+ }
+
+ fn peer_disconnected(&self, their_node_id: &PublicKey) {
+ let mut pending_msgs = self.pending_messages.lock().unwrap();
+ pending_msgs.remove(their_node_id);
+ }
+
+ fn provided_node_features(&self) -> NodeFeatures {
+ let mut features = NodeFeatures::empty();
+ features.set_onion_messages_optional();
+ features
+ }
+
+ fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
+ let mut features = InitFeatures::empty();
+ features.set_onion_messages_optional();
+ features
+ }
+}
+
+impl<ES: Deref, NS: Deref, L: Deref, CMH: Deref> OnionMessageProvider for OnionMessenger<ES, NS, L, CMH>
+ where ES::Target: EntropySource,
+ NS::Target: NodeSigner,
+ L::Target: Logger,
+ CMH::Target: CustomOnionMessageHandler,
+{
+ fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<msgs::OnionMessage> {
+ let mut pending_msgs = self.pending_messages.lock().unwrap();
+ if let Some(msgs) = pending_msgs.get_mut(&peer_node_id) {
+ return msgs.pop_front()
+ }
+ None
+ }