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