_ Git - rust-lightning/blob - lightning/src/onion_message/messenger.rs

   1 // This file is Copyright its original authors, visible in version control
   2 // history.
   3 //
   4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
   5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
   7 // You may not use this file except in accordance with one or both of these
   8 // licenses.
   9
  10 //! LDK sends, receives, and forwards onion messages via the [`OnionMessenger`]. See its docs for
  11 //! more information.
  12
  13 use bitcoin::hashes::{Hash, HashEngine};
  14 use bitcoin::hashes::hmac::{Hmac, HmacEngine};
  15 use bitcoin::hashes::sha256::Hash as Sha256;
  16 use bitcoin::secp256k1::{self, PublicKey, Scalar, Secp256k1, SecretKey};
  17
  18 use crate::blinded_path::{BlindedPath, ForwardTlvs, ReceiveTlvs, utils};
  19 use crate::sign::{EntropySource, KeysManager, NodeSigner, Recipient};
  20 use crate::events::OnionMessageProvider;
  21 use crate::ln::features::{InitFeatures, NodeFeatures};
  22 use crate::ln::msgs::{self, OnionMessageHandler};
  23 use crate::ln::onion_utils;
  24 use crate::ln::peer_handler::IgnoringMessageHandler;
  25 pub use super::packet::{CustomOnionMessageContents, OnionMessageContents};
  26 use super::offers::OffersMessageHandler;
  27 use super::packet::{BIG_PACKET_HOP_DATA_LEN, ForwardControlTlvs, Packet, Payload, ReceiveControlTlvs, SMALL_PACKET_HOP_DATA_LEN};
  28 use crate::util::logger::Logger;
  29 use crate::util::ser::Writeable;
  30
  31 use core::ops::Deref;
  32 use crate::io;
  33 use crate::sync::{Arc, Mutex};
  34 use crate::prelude::*;
  35
  36 /// A sender, receiver and forwarder of onion messages. In upcoming releases, this object will be
  37 /// used to retrieve invoices and fulfill invoice requests from [offers]. Currently, only sending
  38 /// and receiving custom onion messages is supported.
  39 ///
  40 /// # Example
  41 ///
  42 /// ```
  43 /// # extern crate bitcoin;
  44 /// # use bitcoin::hashes::_export::_core::time::Duration;
  45 /// # use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey};
  46 /// # use lightning::blinded_path::BlindedPath;
  47 /// # use lightning::sign::KeysManager;
  48 /// # use lightning::ln::peer_handler::IgnoringMessageHandler;
  49 /// # use lightning::onion_message::{CustomOnionMessageContents, Destination, MessageRouter, OnionMessageContents, OnionMessagePath, OnionMessenger};
  50 /// # use lightning::util::logger::{Logger, Record};
  51 /// # use lightning::util::ser::{Writeable, Writer};
  52 /// # use lightning::io;
  53 /// # use std::sync::Arc;
  54 /// # struct FakeLogger;
  55 /// # impl Logger for FakeLogger {
  56 /// #     fn log(&self, record: &Record) { unimplemented!() }
  57 /// # }
  58 /// # struct FakeMessageRouter {}
  59 /// # impl MessageRouter for FakeMessageRouter {
  60 /// #     fn find_path(&self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination) -> Result<OnionMessagePath, ()> {
  61 /// #         unimplemented!()
  62 /// #     }
  63 /// # }
  64 /// # let seed = [42u8; 32];
  65 /// # let time = Duration::from_secs(123456);
  66 /// # let keys_manager = KeysManager::new(&seed, time.as_secs(), time.subsec_nanos());
  67 /// # let logger = Arc::new(FakeLogger {});
  68 /// # let node_secret = SecretKey::from_slice(&hex::decode("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
  69 /// # let secp_ctx = Secp256k1::new();
  70 /// # let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
  71 /// # let (hop_node_id2, hop_node_id3, hop_node_id4) = (hop_node_id1, hop_node_id1, hop_node_id1);
  72 /// # let destination_node_id = hop_node_id1;
  73 /// # let message_router = Arc::new(FakeMessageRouter {});
  74 /// # let custom_message_handler = IgnoringMessageHandler {};
  75 /// # let offers_message_handler = IgnoringMessageHandler {};
  76 /// // Create the onion messenger. This must use the same `keys_manager` as is passed to your
  77 /// // ChannelManager.
  78 /// let onion_messenger = OnionMessenger::new(
  79 ///     &keys_manager, &keys_manager, logger, message_router, &offers_message_handler,
  80 ///     &custom_message_handler
  81 /// );
  82 ///
  83 /// # struct YourCustomMessage {}
  84 /// impl Writeable for YourCustomMessage {
  85 ///     fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
  86 ///             # Ok(())
  87 ///             // Write your custom onion message to `w`
  88 ///     }
  89 /// }
  90 /// impl CustomOnionMessageContents for YourCustomMessage {
  91 ///     fn tlv_type(&self) -> u64 {
  92 ///             # let your_custom_message_type = 42;
  93 ///             your_custom_message_type
  94 ///     }
  95 /// }
  96 /// // Send a custom onion message to a node id.
  97 /// let path = OnionMessagePath {
  98 ///     intermediate_nodes: vec![hop_node_id1, hop_node_id2],
  99 ///     destination: Destination::Node(destination_node_id),
 100 /// };
 101 /// let reply_path = None;
 102 /// # let your_custom_message = YourCustomMessage {};
 103 /// let message = OnionMessageContents::Custom(your_custom_message);
 104 /// onion_messenger.send_onion_message(path, message, reply_path);
 105 ///
 106 /// // Create a blinded path to yourself, for someone to send an onion message to.
 107 /// # let your_node_id = hop_node_id1;
 108 /// let hops = [hop_node_id3, hop_node_id4, your_node_id];
 109 /// let blinded_path = BlindedPath::new_for_message(&hops, &keys_manager, &secp_ctx).unwrap();
 110 ///
 111 /// // Send a custom onion message to a blinded path.
 112 /// let path = OnionMessagePath {
 113 ///     intermediate_nodes: vec![hop_node_id1, hop_node_id2],
 114 ///     destination: Destination::BlindedPath(blinded_path),
 115 /// };
 116 /// let reply_path = None;
 117 /// # let your_custom_message = YourCustomMessage {};
 118 /// let message = OnionMessageContents::Custom(your_custom_message);
 119 /// onion_messenger.send_onion_message(path, message, reply_path);
 120 /// ```
 121 ///
 122 /// [offers]: <https://github.com/lightning/bolts/pull/798>
 123 /// [`OnionMessenger`]: crate::onion_message::OnionMessenger
 124 pub struct OnionMessenger<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref>
 125 where
 126         ES::Target: EntropySource,
 127         NS::Target: NodeSigner,
 128         L::Target: Logger,
 129         MR::Target: MessageRouter,
 130         OMH::Target: OffersMessageHandler,
 131         CMH:: Target: CustomOnionMessageHandler,
 132 {
 133         entropy_source: ES,
 134         node_signer: NS,
 135         logger: L,
 136         pending_messages: Mutex<HashMap<PublicKey, VecDeque<msgs::OnionMessage>>>,
 137         secp_ctx: Secp256k1<secp256k1::All>,
 138         message_router: MR,
 139         offers_handler: OMH,
 140         custom_handler: CMH,
 141 }
 142
 143 /// A trait defining behavior for routing an [`OnionMessage`].
 144 ///
 145 /// [`OnionMessage`]: msgs::OnionMessage
 146 pub trait MessageRouter {
 147         /// Returns a route for sending an [`OnionMessage`] to the given [`Destination`].
 148         ///
 149         /// [`OnionMessage`]: msgs::OnionMessage
 150         fn find_path(
 151                 &self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
 152         ) -> Result<OnionMessagePath, ()>;
 153 }
 154
 155 /// A path for sending an [`msgs::OnionMessage`].
 156 #[derive(Clone)]
 157 pub struct OnionMessagePath {
 158         /// Nodes on the path between the sender and the destination.
 159         pub intermediate_nodes: Vec<PublicKey>,
 160
 161         /// The recipient of the message.
 162         pub destination: Destination,
 163 }
 164
 165 /// The destination of an onion message.
 166 #[derive(Clone)]
 167 pub enum Destination {
 168         /// We're sending this onion message to a node.
 169         Node(PublicKey),
 170         /// We're sending this onion message to a blinded path.
 171         BlindedPath(BlindedPath),
 172 }
 173
 174 impl Destination {
 175         pub(super) fn num_hops(&self) -> usize {
 176                 match self {
 177                         Destination::Node(_) => 1,
 178                         Destination::BlindedPath(BlindedPath { blinded_hops, .. }) => blinded_hops.len(),
 179                 }
 180         }
 181 }
 182
 183 /// Errors that may occur when [sending an onion message].
 184 ///
 185 /// [sending an onion message]: OnionMessenger::send_onion_message
 186 #[derive(Debug, PartialEq, Eq)]
 187 pub enum SendError {
 188         /// Errored computing onion message packet keys.
 189         Secp256k1(secp256k1::Error),
 190         /// Because implementations such as Eclair will drop onion messages where the message packet
 191         /// exceeds 32834 bytes, we refuse to send messages where the packet exceeds this size.
 192         TooBigPacket,
 193         /// The provided [`Destination`] was an invalid [`BlindedPath`], due to having fewer than two
 194         /// blinded hops.
 195         TooFewBlindedHops,
 196         /// Our next-hop peer was offline or does not support onion message forwarding.
 197         InvalidFirstHop,
 198         /// Onion message contents must have a TLV type >= 64.
 199         InvalidMessage,
 200         /// Our next-hop peer's buffer was full or our total outbound buffer was full.
 201         BufferFull,
 202         /// Failed to retrieve our node id from the provided [`NodeSigner`].
 203         ///
 204         /// [`NodeSigner`]: crate::sign::NodeSigner
 205         GetNodeIdFailed,
 206         /// We attempted to send to a blinded path where we are the introduction node, and failed to
 207         /// advance the blinded path to make the second hop the new introduction node. Either
 208         /// [`NodeSigner::ecdh`] failed, we failed to tweak the current blinding point to get the
 209         /// new blinding point, or we were attempting to send to ourselves.
 210         BlindedPathAdvanceFailed,
 211 }
 212
 213 /// Handler for custom onion messages. If you are using [`SimpleArcOnionMessenger`],
 214 /// [`SimpleRefOnionMessenger`], or prefer to ignore inbound custom onion messages,
 215 /// [`IgnoringMessageHandler`] must be provided to [`OnionMessenger::new`]. Otherwise, a custom
 216 /// implementation of this trait must be provided, with [`CustomMessage`] specifying the supported
 217 /// message types.
 218 ///
 219 /// See [`OnionMessenger`] for example usage.
 220 ///
 221 /// [`IgnoringMessageHandler`]: crate::ln::peer_handler::IgnoringMessageHandler
 222 /// [`CustomMessage`]: Self::CustomMessage
 223 pub trait CustomOnionMessageHandler {
 224         /// The message known to the handler. To support multiple message types, you may want to make this
 225         /// an enum with a variant for each supported message.
 226         type CustomMessage: CustomOnionMessageContents;
 227         /// Called with the custom message that was received.
 228         fn handle_custom_message(&self, msg: Self::CustomMessage);
 229         /// Read a custom message of type `message_type` from `buffer`, returning `Ok(None)` if the
 230         /// message type is unknown.
 231         fn read_custom_message<R: io::Read>(&self, message_type: u64, buffer: &mut R) -> Result<Option<Self::CustomMessage>, msgs::DecodeError>;
 232 }
 233
 234 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref>
 235 OnionMessenger<ES, NS, L, MR, OMH, CMH>
 236 where
 237         ES::Target: EntropySource,
 238         NS::Target: NodeSigner,
 239         L::Target: Logger,
 240         MR::Target: MessageRouter,
 241         OMH::Target: OffersMessageHandler,
 242         CMH::Target: CustomOnionMessageHandler,
 243 {
 244         /// Constructs a new `OnionMessenger` to send, forward, and delegate received onion messages to
 245         /// their respective handlers.
 246         pub fn new(
 247                 entropy_source: ES, node_signer: NS, logger: L, message_router: MR, offers_handler: OMH,
 248                 custom_handler: CMH
 249         ) -> Self {
 250                 let mut secp_ctx = Secp256k1::new();
 251                 secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
 252                 OnionMessenger {
 253                         entropy_source,
 254                         node_signer,
 255                         pending_messages: Mutex::new(HashMap::new()),
 256                         secp_ctx,
 257                         logger,
 258                         message_router,
 259                         offers_handler,
 260                         custom_handler,
 261                 }
 262         }
 263
 264         /// Send an onion message with contents `message` to the destination of `path`.
 265         ///
 266         /// See [`OnionMessenger`] for example usage.
 267         pub fn send_onion_message<T: CustomOnionMessageContents>(
 268                 &self, path: OnionMessagePath, message: OnionMessageContents<T>,
 269                 reply_path: Option<BlindedPath>
 270         ) -> Result<(), SendError> {
 271                 let OnionMessagePath { intermediate_nodes, mut destination } = path;
 272                 if let Destination::BlindedPath(BlindedPath { ref blinded_hops, .. }) = destination {
 273                         if blinded_hops.len() < 2 {
 274                                 return Err(SendError::TooFewBlindedHops);
 275                         }
 276                 }
 277
 278                 if message.tlv_type() < 64 { return Err(SendError::InvalidMessage) }
 279
 280                 // If we are sending straight to a blinded path and we are the introduction node, we need to
 281                 // advance the blinded path by 1 hop so the second hop is the new introduction node.
 282                 if intermediate_nodes.len() == 0 {
 283                         if let Destination::BlindedPath(ref mut blinded_path) = destination {
 284                                 let our_node_id = self.node_signer.get_node_id(Recipient::Node)
 285                                         .map_err(|()| SendError::GetNodeIdFailed)?;
 286                                 if blinded_path.introduction_node_id == our_node_id {
 287                                         blinded_path.advance_message_path_by_one(&self.node_signer, &self.secp_ctx)
 288                                                 .map_err(|()| SendError::BlindedPathAdvanceFailed)?;
 289                                 }
 290                         }
 291                 }
 292
 293                 let blinding_secret_bytes = self.entropy_source.get_secure_random_bytes();
 294                 let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
 295                 let (introduction_node_id, blinding_point) = if intermediate_nodes.len() != 0 {
 296                         (intermediate_nodes[0], PublicKey::from_secret_key(&self.secp_ctx, &blinding_secret))
 297                 } else {
 298                         match destination {
 299                                 Destination::Node(pk) => (pk, PublicKey::from_secret_key(&self.secp_ctx, &blinding_secret)),
 300                                 Destination::BlindedPath(BlindedPath { introduction_node_id, blinding_point, .. }) =>
 301                                         (introduction_node_id, blinding_point),
 302                         }
 303                 };
 304                 let (packet_payloads, packet_keys) = packet_payloads_and_keys(
 305                         &self.secp_ctx, &intermediate_nodes, destination, message, reply_path, &blinding_secret)
 306                         .map_err(|e| SendError::Secp256k1(e))?;
 307
 308                 let prng_seed = self.entropy_source.get_secure_random_bytes();
 309                 let onion_routing_packet = construct_onion_message_packet(
 310                         packet_payloads, packet_keys, prng_seed).map_err(|()| SendError::TooBigPacket)?;
 311
 312                 let mut pending_per_peer_msgs = self.pending_messages.lock().unwrap();
 313                 if outbound_buffer_full(&introduction_node_id, &pending_per_peer_msgs) { return Err(SendError::BufferFull) }
 314                 match pending_per_peer_msgs.entry(introduction_node_id) {
 315                         hash_map::Entry::Vacant(_) => Err(SendError::InvalidFirstHop),
 316                         hash_map::Entry::Occupied(mut e) => {
 317                                 e.get_mut().push_back(msgs::OnionMessage { blinding_point, onion_routing_packet });
 318                                 Ok(())
 319                         }
 320                 }
 321         }
 322
 323         #[cfg(test)]
 324         pub(super) fn release_pending_msgs(&self) -> HashMap<PublicKey, VecDeque<msgs::OnionMessage>> {
 325                 let mut pending_msgs = self.pending_messages.lock().unwrap();
 326                 let mut msgs = HashMap::new();
 327                 // We don't want to disconnect the peers by removing them entirely from the original map, so we
 328                 // swap the pending message buffers individually.
 329                 for (peer_node_id, pending_messages) in &mut *pending_msgs {
 330                         msgs.insert(*peer_node_id, core::mem::take(pending_messages));
 331                 }
 332                 msgs
 333         }
 334 }
 335
 336 fn outbound_buffer_full(peer_node_id: &PublicKey, buffer: &HashMap<PublicKey, VecDeque<msgs::OnionMessage>>) -> bool {
 337         const MAX_TOTAL_BUFFER_SIZE: usize = (1 << 20) * 128;
 338         const MAX_PER_PEER_BUFFER_SIZE: usize = (1 << 10) * 256;
 339         let mut total_buffered_bytes = 0;
 340         let mut peer_buffered_bytes = 0;
 341         for (pk, peer_buf) in buffer {
 342                 for om in peer_buf {
 343                         let om_len = om.serialized_length();
 344                         if pk == peer_node_id {
 345                                 peer_buffered_bytes += om_len;
 346                         }
 347                         total_buffered_bytes += om_len;
 348
 349                         if total_buffered_bytes >= MAX_TOTAL_BUFFER_SIZE ||
 350                                 peer_buffered_bytes >= MAX_PER_PEER_BUFFER_SIZE
 351                         {
 352                                 return true
 353                         }
 354                 }
 355         }
 356         false
 357 }
 358
 359 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref> OnionMessageHandler
 360 for OnionMessenger<ES, NS, L, MR, OMH, CMH>
 361 where
 362         ES::Target: EntropySource,
 363         NS::Target: NodeSigner,
 364         L::Target: Logger,
 365         MR::Target: MessageRouter,
 366         OMH::Target: OffersMessageHandler,
 367         CMH::Target: CustomOnionMessageHandler + Sized,
 368 {
 369         /// Handle an incoming onion message. Currently, if a message was destined for us we will log, but
 370         /// soon we'll delegate the onion message to a handler that can generate invoices or send
 371         /// payments.
 372         fn handle_onion_message(&self, _peer_node_id: &PublicKey, msg: &msgs::OnionMessage) {
 373                 let control_tlvs_ss = match self.node_signer.ecdh(Recipient::Node, &msg.blinding_point, None) {
 374                         Ok(ss) => ss,
 375                         Err(e) =>  {
 376                                 log_error!(self.logger, "Failed to retrieve node secret: {:?}", e);
 377                                 return
 378                         }
 379                 };
 380                 let onion_decode_ss = {
 381                         let blinding_factor = {
 382                                 let mut hmac = HmacEngine::<Sha256>::new(b"blinded_node_id");
 383                                 hmac.input(control_tlvs_ss.as_ref());
 384                                 Hmac::from_engine(hmac).into_inner()
 385                         };
 386                         match self.node_signer.ecdh(Recipient::Node, &msg.onion_routing_packet.public_key,
 387                                 Some(&Scalar::from_be_bytes(blinding_factor).unwrap()))
 388                         {
 389                                 Ok(ss) => ss.secret_bytes(),
 390                                 Err(()) => {
 391                                         log_trace!(self.logger, "Failed to compute onion packet shared secret");
 392                                         return
 393                                 }
 394                         }
 395                 };
 396                 match onion_utils::decode_next_untagged_hop(
 397                         onion_decode_ss, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
 398                         (control_tlvs_ss, &*self.custom_handler, &*self.logger)
 399                 ) {
 400                         Ok((Payload::Receive::<<<CMH as Deref>::Target as CustomOnionMessageHandler>::CustomMessage> {
 401                                 message, control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id }), reply_path,
 402                         }, None)) => {
 403                                 log_info!(self.logger,
 404                                         "Received an onion message with path_id {:02x?} and {} reply_path",
 405                                                 path_id, if reply_path.is_some() { "a" } else { "no" });
 406                                 match message {
 407                                         OnionMessageContents::Offers(msg) => self.offers_handler.handle_message(msg),
 408                                         OnionMessageContents::Custom(msg) => self.custom_handler.handle_custom_message(msg),
 409                                 }
 410                         },
 411                         Ok((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
 412                                 next_node_id, next_blinding_override
 413                         })), Some((next_hop_hmac, new_packet_bytes)))) => {
 414                                 // TODO: we need to check whether `next_node_id` is our node, in which case this is a dummy
 415                                 // blinded hop and this onion message is destined for us. In this situation, we should keep
 416                                 // unwrapping the onion layers to get to the final payload. Since we don't have the option
 417                                 // of creating blinded paths with dummy hops currently, we should be ok to not handle this
 418                                 // for now.
 419                                 let new_pubkey = match onion_utils::next_hop_packet_pubkey(&self.secp_ctx, msg.onion_routing_packet.public_key, &onion_decode_ss) {
 420                                         Ok(pk) => pk,
 421                                         Err(e) => {
 422                                                 log_trace!(self.logger, "Failed to compute next hop packet pubkey: {}", e);
 423                                                 return
 424                                         }
 425                                 };
 426                                 let outgoing_packet = Packet {
 427                                         version: 0,
 428                                         public_key: new_pubkey,
 429                                         hop_data: new_packet_bytes,
 430                                         hmac: next_hop_hmac,
 431                                 };
 432                                 let onion_message = msgs::OnionMessage {
 433                                         blinding_point: match next_blinding_override {
 434                                                 Some(blinding_point) => blinding_point,
 435                                                 None => {
 436                                                         let blinding_factor = {
 437                                                                 let mut sha = Sha256::engine();
 438                                                                 sha.input(&msg.blinding_point.serialize()[..]);
 439                                                                 sha.input(control_tlvs_ss.as_ref());
 440                                                                 Sha256::from_engine(sha).into_inner()
 441                                                         };
 442                                                         let next_blinding_point = msg.blinding_point;
 443                                                         match next_blinding_point.mul_tweak(&self.secp_ctx, &Scalar::from_be_bytes(blinding_factor).unwrap()) {
 444                                                                 Ok(bp) => bp,
 445                                                                 Err(e) => {
 446                                                                         log_trace!(self.logger, "Failed to compute next blinding point: {}", e);
 447                                                                         return
 448                                                                 }
 449                                                         }
 450                                                 },
 451                                         },
 452                                         onion_routing_packet: outgoing_packet,
 453                                 };
 454
 455                                 let mut pending_per_peer_msgs = self.pending_messages.lock().unwrap();
 456                                 if outbound_buffer_full(&next_node_id, &pending_per_peer_msgs) {
 457                                         log_trace!(self.logger, "Dropping forwarded onion message to peer {:?}: outbound buffer full", next_node_id);
 458                                         return
 459                                 }
 460
 461                                 #[cfg(fuzzing)]
 462                                 pending_per_peer_msgs.entry(next_node_id).or_insert_with(VecDeque::new);
 463
 464                                 match pending_per_peer_msgs.entry(next_node_id) {
 465                                         hash_map::Entry::Vacant(_) => {
 466                                                 log_trace!(self.logger, "Dropping forwarded onion message to disconnected peer {:?}", next_node_id);
 467                                                 return
 468                                         },
 469                                         hash_map::Entry::Occupied(mut e) => {
 470                                                 e.get_mut().push_back(onion_message);
 471                                                 log_trace!(self.logger, "Forwarding an onion message to peer {}", next_node_id);
 472                                         }
 473                                 };
 474                         },
 475                         Err(e) => {
 476                                 log_trace!(self.logger, "Errored decoding onion message packet: {:?}", e);
 477                         },
 478                         _ => {
 479                                 log_trace!(self.logger, "Received bogus onion message packet, either the sender encoded a final hop as a forwarding hop or vice versa");
 480                         },
 481                 };
 482         }
 483
 484         fn peer_connected(&self, their_node_id: &PublicKey, init: &msgs::Init, _inbound: bool) -> Result<(), ()> {
 485                 if init.features.supports_onion_messages() {
 486                         let mut peers = self.pending_messages.lock().unwrap();
 487                         peers.insert(their_node_id.clone(), VecDeque::new());
 488                 }
 489                 Ok(())
 490         }
 491
 492         fn peer_disconnected(&self, their_node_id: &PublicKey) {
 493                 let mut pending_msgs = self.pending_messages.lock().unwrap();
 494                 pending_msgs.remove(their_node_id);
 495         }
 496
 497         fn provided_node_features(&self) -> NodeFeatures {
 498                 let mut features = NodeFeatures::empty();
 499                 features.set_onion_messages_optional();
 500                 features
 501         }
 502
 503         fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
 504                 let mut features = InitFeatures::empty();
 505                 features.set_onion_messages_optional();
 506                 features
 507         }
 508 }
 509
 510 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref> OnionMessageProvider
 511 for OnionMessenger<ES, NS, L, MR, OMH, CMH>
 512 where
 513         ES::Target: EntropySource,
 514         NS::Target: NodeSigner,
 515         L::Target: Logger,
 516         MR::Target: MessageRouter,
 517         OMH::Target: OffersMessageHandler,
 518         CMH::Target: CustomOnionMessageHandler,
 519 {
 520         fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<msgs::OnionMessage> {
 521                 let mut pending_msgs = self.pending_messages.lock().unwrap();
 522                 if let Some(msgs) = pending_msgs.get_mut(&peer_node_id) {
 523                         return msgs.pop_front()
 524                 }
 525                 None
 526         }
 527 }
 528
 529 // TODO: parameterize the below Simple* types with OnionMessenger and handle the messages it
 530 // produces
 531 /// Useful for simplifying the parameters of [`SimpleArcChannelManager`] and
 532 /// [`SimpleArcPeerManager`]. See their docs for more details.
 533 ///
 534 /// This is not exported to bindings users as `Arc`s don't make sense in bindings.
 535 ///
 536 /// [`SimpleArcChannelManager`]: crate::ln::channelmanager::SimpleArcChannelManager
 537 /// [`SimpleArcPeerManager`]: crate::ln::peer_handler::SimpleArcPeerManager
 538 pub type SimpleArcOnionMessenger<L, R> = OnionMessenger<
 539         Arc<KeysManager>,
 540         Arc<KeysManager>,
 541         Arc<L>,
 542         Arc<R>,
 543         IgnoringMessageHandler,
 544         IgnoringMessageHandler
 545 >;
 546
 547 /// Useful for simplifying the parameters of [`SimpleRefChannelManager`] and
 548 /// [`SimpleRefPeerManager`]. See their docs for more details.
 549 ///
 550 /// This is not exported to bindings users as general type aliases don't make sense in bindings.
 551 ///
 552 /// [`SimpleRefChannelManager`]: crate::ln::channelmanager::SimpleRefChannelManager
 553 /// [`SimpleRefPeerManager`]: crate::ln::peer_handler::SimpleRefPeerManager
 554 pub type SimpleRefOnionMessenger<'a, 'b, 'c, L, R> = OnionMessenger<
 555         &'a KeysManager,
 556         &'a KeysManager,
 557         &'b L,
 558         &'c R,
 559         IgnoringMessageHandler,
 560         IgnoringMessageHandler
 561 >;
 562
 563 /// Construct onion packet payloads and keys for sending an onion message along the given
 564 /// `unblinded_path` to the given `destination`.
 565 fn packet_payloads_and_keys<T: CustomOnionMessageContents, S: secp256k1::Signing + secp256k1::Verification>(
 566         secp_ctx: &Secp256k1<S>, unblinded_path: &[PublicKey], destination: Destination,
 567         message: OnionMessageContents<T>, mut reply_path: Option<BlindedPath>, session_priv: &SecretKey
 568 ) -> Result<(Vec<(Payload<T>, [u8; 32])>, Vec<onion_utils::OnionKeys>), secp256k1::Error> {
 569         let num_hops = unblinded_path.len() + destination.num_hops();
 570         let mut payloads = Vec::with_capacity(num_hops);
 571         let mut onion_packet_keys = Vec::with_capacity(num_hops);
 572
 573         let (mut intro_node_id_blinding_pt, num_blinded_hops) = if let Destination::BlindedPath(BlindedPath {
 574                 introduction_node_id, blinding_point, blinded_hops }) = &destination {
 575                 (Some((*introduction_node_id, *blinding_point)), blinded_hops.len()) } else { (None, 0) };
 576         let num_unblinded_hops = num_hops - num_blinded_hops;
 577
 578         let mut unblinded_path_idx = 0;
 579         let mut blinded_path_idx = 0;
 580         let mut prev_control_tlvs_ss = None;
 581         let mut final_control_tlvs = None;
 582         utils::construct_keys_callback(secp_ctx, unblinded_path, Some(destination), session_priv, |_, onion_packet_ss, ephemeral_pubkey, control_tlvs_ss, unblinded_pk_opt, enc_payload_opt| {
 583                 if num_unblinded_hops != 0 && unblinded_path_idx < num_unblinded_hops {
 584                         if let Some(ss) = prev_control_tlvs_ss.take() {
 585                                 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(
 586                                         ForwardTlvs {
 587                                                 next_node_id: unblinded_pk_opt.unwrap(),
 588                                                 next_blinding_override: None,
 589                                         }
 590                                 )), ss));
 591                         }
 592                         prev_control_tlvs_ss = Some(control_tlvs_ss);
 593                         unblinded_path_idx += 1;
 594                 } else if let Some((intro_node_id, blinding_pt)) = intro_node_id_blinding_pt.take() {
 595                         if let Some(control_tlvs_ss) = prev_control_tlvs_ss.take() {
 596                                 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
 597                                         next_node_id: intro_node_id,
 598                                         next_blinding_override: Some(blinding_pt),
 599                                 })), control_tlvs_ss));
 600                         }
 601                 }
 602                 if blinded_path_idx < num_blinded_hops.saturating_sub(1) && enc_payload_opt.is_some() {
 603                         payloads.push((Payload::Forward(ForwardControlTlvs::Blinded(enc_payload_opt.unwrap())),
 604                                 control_tlvs_ss));
 605                         blinded_path_idx += 1;
 606                 } else if let Some(encrypted_payload) = enc_payload_opt {
 607                         final_control_tlvs = Some(ReceiveControlTlvs::Blinded(encrypted_payload));
 608                         prev_control_tlvs_ss = Some(control_tlvs_ss);
 609                 }
 610
 611                 let (rho, mu) = onion_utils::gen_rho_mu_from_shared_secret(onion_packet_ss.as_ref());
 612                 onion_packet_keys.push(onion_utils::OnionKeys {
 613                         #[cfg(test)]
 614                         shared_secret: onion_packet_ss,
 615                         #[cfg(test)]
 616                         blinding_factor: [0; 32],
 617                         ephemeral_pubkey,
 618                         rho,
 619                         mu,
 620                 });
 621         })?;
 622
 623         if let Some(control_tlvs) = final_control_tlvs {
 624                 payloads.push((Payload::Receive {
 625                         control_tlvs,
 626                         reply_path: reply_path.take(),
 627                         message,
 628                 }, prev_control_tlvs_ss.unwrap()));
 629         } else {
 630                 payloads.push((Payload::Receive {
 631                         control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id: None, }),
 632                         reply_path: reply_path.take(),
 633                         message,
 634                 }, prev_control_tlvs_ss.unwrap()));
 635         }
 636
 637         Ok((payloads, onion_packet_keys))
 638 }
 639
 640 /// Errors if the serialized payload size exceeds onion_message::BIG_PACKET_HOP_DATA_LEN
 641 fn construct_onion_message_packet<T: CustomOnionMessageContents>(payloads: Vec<(Payload<T>, [u8; 32])>, onion_keys: Vec<onion_utils::OnionKeys>, prng_seed: [u8; 32]) -> Result<Packet, ()> {
 642         // Spec rationale:
 643         // "`len` allows larger messages to be sent than the standard 1300 bytes allowed for an HTLC
 644         // onion, but this should be used sparingly as it is reduces anonymity set, hence the
 645         // recommendation that it either look like an HTLC onion, or if larger, be a fixed size."
 646         let payloads_ser_len = onion_utils::payloads_serialized_length(&payloads);
 647         let hop_data_len = if payloads_ser_len <= SMALL_PACKET_HOP_DATA_LEN {
 648                 SMALL_PACKET_HOP_DATA_LEN
 649         } else if payloads_ser_len <= BIG_PACKET_HOP_DATA_LEN {
 650                 BIG_PACKET_HOP_DATA_LEN
 651         } else { return Err(()) };
 652
 653         onion_utils::construct_onion_message_packet::<_, _>(
 654                 payloads, onion_keys, prng_seed, hop_data_len)
 655 }