+
+ /// Send an empty onion message to `destination`, routing it through `intermediate_nodes`.
+ /// See [`OnionMessenger`] for example usage.
+ pub fn send_onion_message(&self, intermediate_nodes: &[PublicKey], destination: Destination) -> Result<(), SendError> {
+ if let Destination::BlindedRoute(BlindedRoute { ref blinded_hops, .. }) = destination {
+ if blinded_hops.len() < 2 {
+ return Err(SendError::TooFewBlindedHops);
+ }
+ }
+ let blinding_secret_bytes = self.keys_manager.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::BlindedRoute(BlindedRoute { 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, &blinding_secret)
+ .map_err(|e| SendError::Secp256k1(e))?;
+
+ let prng_seed = self.keys_manager.get_secure_random_bytes();
+ let onion_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();
+ let pending_msgs = pending_per_peer_msgs.entry(introduction_node_id).or_insert(Vec::new());
+ pending_msgs.push(
+ msgs::OnionMessage {
+ blinding_point,
+ onion_routing_packet: onion_packet,
+ }
+ );
+ Ok(())
+ }
+
+ /// 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.
+ pub fn handle_onion_message(&self, _peer_node_id: &PublicKey, msg: &msgs::OnionMessage) {
+ let control_tlvs_ss = match self.keys_manager.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.keys_manager.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_hop(onion_decode_ss, &msg.onion_routing_packet.hop_data[..],
+ msg.onion_routing_packet.hmac, control_tlvs_ss)
+ {
+ Ok((Payload::Receive {
+ control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id })
+ }, None)) => {
+ log_info!(self.logger, "Received an onion message with path_id: {:02x?}", path_id);
+ },
+ 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 routes 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 mut pending_per_peer_msgs = self.pending_messages.lock().unwrap();
+ let pending_msgs = pending_per_peer_msgs.entry(next_node_id).or_insert(Vec::new());
+ pending_msgs.push(
+ 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 mut 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,
+ },
+ );
+ },
+ 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");
+ },
+ };
+ }
+
+ #[cfg(test)]
+ pub(super) fn release_pending_msgs(&self) -> HashMap<PublicKey, Vec<msgs::OnionMessage>> {
+ let mut pending_msgs = self.pending_messages.lock().unwrap();
+ let mut msgs = HashMap::new();
+ core::mem::swap(&mut *pending_msgs, &mut msgs);
+ msgs
+ }