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