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