_ 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;
  19 use crate::blinded_path::message::{advance_path_by_one, ForwardTlvs, ReceiveTlvs};
  20 use crate::blinded_path::utils;
  21 use crate::events::{Event, EventHandler, EventsProvider};
  22 use crate::sign::{EntropySource, KeysManager, NodeSigner, Recipient};
  23 #[cfg(not(c_bindings))]
  24 use crate::ln::channelmanager::{SimpleArcChannelManager, SimpleRefChannelManager};
  25 use crate::ln::features::{InitFeatures, NodeFeatures};
  26 use crate::ln::msgs::{self, OnionMessage, OnionMessageHandler, SocketAddress};
  27 use crate::ln::onion_utils;
  28 use crate::ln::peer_handler::IgnoringMessageHandler;
  29 use crate::routing::gossip::{NetworkGraph, NodeId};
  30 pub use super::packet::OnionMessageContents;
  31 use super::packet::ParsedOnionMessageContents;
  32 use super::offers::OffersMessageHandler;
  33 use super::packet::{BIG_PACKET_HOP_DATA_LEN, ForwardControlTlvs, Packet, Payload, ReceiveControlTlvs, SMALL_PACKET_HOP_DATA_LEN};
  34 use crate::util::logger::Logger;
  35 use crate::util::ser::Writeable;
  36
  37 use core::fmt;
  38 use core::ops::Deref;
  39 use crate::io;
  40 use crate::sync::{Arc, Mutex};
  41 use crate::prelude::*;
  42
  43 pub(super) const MAX_TIMER_TICKS: usize = 2;
  44
  45 /// A sender, receiver and forwarder of [`OnionMessage`]s.
  46 ///
  47 /// # Handling Messages
  48 ///
  49 /// `OnionMessenger` implements [`OnionMessageHandler`], making it responsible for either forwarding
  50 /// messages to peers or delegating to the appropriate handler for the message type. Currently, the
  51 /// available handlers are:
  52 /// * [`OffersMessageHandler`], for responding to [`InvoiceRequest`]s and paying [`Bolt12Invoice`]s
  53 /// * [`CustomOnionMessageHandler`], for handling user-defined message types
  54 ///
  55 /// # Sending Messages
  56 ///
  57 /// [`OnionMessage`]s are sent initially using [`OnionMessenger::send_onion_message`]. When handling
  58 /// a message, the matched handler may return a response message which `OnionMessenger` will send
  59 /// on its behalf.
  60 ///
  61 /// # Example
  62 ///
  63 /// ```
  64 /// # extern crate bitcoin;
  65 /// # use bitcoin::hashes::_export::_core::time::Duration;
  66 /// # use bitcoin::hashes::hex::FromHex;
  67 /// # use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey, self};
  68 /// # use lightning::blinded_path::BlindedPath;
  69 /// # use lightning::sign::{EntropySource, KeysManager};
  70 /// # use lightning::ln::peer_handler::IgnoringMessageHandler;
  71 /// # use lightning::onion_message::{OnionMessageContents, Destination, MessageRouter, OnionMessagePath, OnionMessenger};
  72 /// # use lightning::util::logger::{Logger, Record};
  73 /// # use lightning::util::ser::{Writeable, Writer};
  74 /// # use lightning::io;
  75 /// # use std::sync::Arc;
  76 /// # struct FakeLogger;
  77 /// # impl Logger for FakeLogger {
  78 /// #     fn log(&self, record: Record) { println!("{:?}" , record); }
  79 /// # }
  80 /// # struct FakeMessageRouter {}
  81 /// # impl MessageRouter for FakeMessageRouter {
  82 /// #     fn find_path(&self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination) -> Result<OnionMessagePath, ()> {
  83 /// #         let secp_ctx = Secp256k1::new();
  84 /// #         let node_secret = SecretKey::from_slice(&<Vec<u8>>::from_hex("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
  85 /// #         let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
  86 /// #         let hop_node_id2 = hop_node_id1;
  87 /// #         Ok(OnionMessagePath {
  88 /// #             intermediate_nodes: vec![hop_node_id1, hop_node_id2],
  89 /// #             destination,
  90 /// #             first_node_addresses: None,
  91 /// #         })
  92 /// #     }
  93 /// #     fn create_blinded_paths<ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
  94 /// #         &self, _recipient: PublicKey, _peers: Vec<PublicKey>, _entropy_source: &ES, _secp_ctx: &Secp256k1<T>
  95 /// #     ) -> Result<Vec<BlindedPath>, ()> {
  96 /// #         unreachable!()
  97 /// #     }
  98 /// # }
  99 /// # let seed = [42u8; 32];
 100 /// # let time = Duration::from_secs(123456);
 101 /// # let keys_manager = KeysManager::new(&seed, time.as_secs(), time.subsec_nanos());
 102 /// # let logger = Arc::new(FakeLogger {});
 103 /// # let node_secret = SecretKey::from_slice(&<Vec<u8>>::from_hex("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
 104 /// # let secp_ctx = Secp256k1::new();
 105 /// # let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
 106 /// # let (hop_node_id3, hop_node_id4) = (hop_node_id1, hop_node_id1);
 107 /// # let destination_node_id = hop_node_id1;
 108 /// # let message_router = Arc::new(FakeMessageRouter {});
 109 /// # let custom_message_handler = IgnoringMessageHandler {};
 110 /// # let offers_message_handler = IgnoringMessageHandler {};
 111 /// // Create the onion messenger. This must use the same `keys_manager` as is passed to your
 112 /// // ChannelManager.
 113 /// let onion_messenger = OnionMessenger::new(
 114 ///     &keys_manager, &keys_manager, logger, message_router, &offers_message_handler,
 115 ///     &custom_message_handler
 116 /// );
 117
 118 /// # #[derive(Debug)]
 119 /// # struct YourCustomMessage {}
 120 /// impl Writeable for YourCustomMessage {
 121 ///     fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
 122 ///             # Ok(())
 123 ///             // Write your custom onion message to `w`
 124 ///     }
 125 /// }
 126 /// impl OnionMessageContents for YourCustomMessage {
 127 ///     fn tlv_type(&self) -> u64 {
 128 ///             # let your_custom_message_type = 42;
 129 ///             your_custom_message_type
 130 ///     }
 131 /// }
 132 /// // Send a custom onion message to a node id.
 133 /// let destination = Destination::Node(destination_node_id);
 134 /// let reply_path = None;
 135 /// # let message = YourCustomMessage {};
 136 /// onion_messenger.send_onion_message(message, destination, reply_path);
 137 ///
 138 /// // Create a blinded path to yourself, for someone to send an onion message to.
 139 /// # let your_node_id = hop_node_id1;
 140 /// let hops = [hop_node_id3, hop_node_id4, your_node_id];
 141 /// let blinded_path = BlindedPath::new_for_message(&hops, &keys_manager, &secp_ctx).unwrap();
 142 ///
 143 /// // Send a custom onion message to a blinded path.
 144 /// let destination = Destination::BlindedPath(blinded_path);
 145 /// let reply_path = None;
 146 /// # let message = YourCustomMessage {};
 147 /// onion_messenger.send_onion_message(message, destination, reply_path);
 148 /// ```
 149 ///
 150 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 151 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 152 pub struct OnionMessenger<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref>
 153 where
 154         ES::Target: EntropySource,
 155         NS::Target: NodeSigner,
 156         L::Target: Logger,
 157         MR::Target: MessageRouter,
 158         OMH::Target: OffersMessageHandler,
 159         CMH::Target: CustomOnionMessageHandler,
 160 {
 161         entropy_source: ES,
 162         node_signer: NS,
 163         logger: L,
 164         message_recipients: Mutex<HashMap<PublicKey, OnionMessageRecipient>>,
 165         secp_ctx: Secp256k1<secp256k1::All>,
 166         message_router: MR,
 167         offers_handler: OMH,
 168         custom_handler: CMH,
 169 }
 170
 171 /// [`OnionMessage`]s buffered to be sent.
 172 enum OnionMessageRecipient {
 173         /// Messages for a node connected as a peer.
 174         ConnectedPeer(VecDeque<OnionMessage>),
 175
 176         /// Messages for a node that is not yet connected, which are dropped after [`MAX_TIMER_TICKS`]
 177         /// and tracked here.
 178         PendingConnection(VecDeque<OnionMessage>, Option<Vec<SocketAddress>>, usize),
 179 }
 180
 181 impl OnionMessageRecipient {
 182         fn pending_connection(addresses: Vec<SocketAddress>) -> Self {
 183                 Self::PendingConnection(VecDeque::new(), Some(addresses), 0)
 184         }
 185
 186         fn pending_messages(&self) -> &VecDeque<OnionMessage> {
 187                 match self {
 188                         OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
 189                         OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
 190                 }
 191         }
 192
 193         fn enqueue_message(&mut self, message: OnionMessage) {
 194                 let pending_messages = match self {
 195                         OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
 196                         OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
 197                 };
 198
 199                 pending_messages.push_back(message);
 200         }
 201
 202         fn dequeue_message(&mut self) -> Option<OnionMessage> {
 203                 let pending_messages = match self {
 204                         OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
 205                         OnionMessageRecipient::PendingConnection(pending_messages, _, _) => {
 206                                 debug_assert!(false);
 207                                 pending_messages
 208                         },
 209                 };
 210
 211                 pending_messages.pop_front()
 212         }
 213
 214         #[cfg(test)]
 215         fn release_pending_messages(&mut self) -> VecDeque<OnionMessage> {
 216                 let pending_messages = match self {
 217                         OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
 218                         OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
 219                 };
 220
 221                 core::mem::take(pending_messages)
 222         }
 223
 224         fn mark_connected(&mut self) {
 225                 if let OnionMessageRecipient::PendingConnection(pending_messages, _, _) = self {
 226                         let mut new_pending_messages = VecDeque::new();
 227                         core::mem::swap(pending_messages, &mut new_pending_messages);
 228                         *self = OnionMessageRecipient::ConnectedPeer(new_pending_messages);
 229                 }
 230         }
 231
 232         fn is_connected(&self) -> bool {
 233                 match self {
 234                         OnionMessageRecipient::ConnectedPeer(..) => true,
 235                         OnionMessageRecipient::PendingConnection(..) => false,
 236                 }
 237         }
 238 }
 239
 240 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
 241 ///
 242 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
 243 /// enqueued for sending.
 244 #[cfg(not(c_bindings))]
 245 pub struct PendingOnionMessage<T: OnionMessageContents> {
 246         /// The message contents to send in an [`OnionMessage`].
 247         pub contents: T,
 248
 249         /// The destination of the message.
 250         pub destination: Destination,
 251
 252         /// A reply path to include in the [`OnionMessage`] for a response.
 253         pub reply_path: Option<BlindedPath>,
 254 }
 255
 256 #[cfg(c_bindings)]
 257 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
 258 ///
 259 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
 260 /// enqueued for sending.
 261 pub type PendingOnionMessage<T: OnionMessageContents> = (T, Destination, Option<BlindedPath>);
 262
 263 pub(crate) fn new_pending_onion_message<T: OnionMessageContents>(
 264         contents: T, destination: Destination, reply_path: Option<BlindedPath>
 265 ) -> PendingOnionMessage<T> {
 266         #[cfg(not(c_bindings))]
 267         return PendingOnionMessage { contents, destination, reply_path };
 268         #[cfg(c_bindings)]
 269         return (contents, destination, reply_path);
 270 }
 271
 272 /// A trait defining behavior for routing an [`OnionMessage`].
 273 pub trait MessageRouter {
 274         /// Returns a route for sending an [`OnionMessage`] to the given [`Destination`].
 275         fn find_path(
 276                 &self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
 277         ) -> Result<OnionMessagePath, ()>;
 278
 279         /// Creates [`BlindedPath`]s to the `recipient` node. The nodes in `peers` are assumed to be
 280         /// direct peers with the `recipient`.
 281         fn create_blinded_paths<
 282                 ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification
 283         >(
 284                 &self, recipient: PublicKey, peers: Vec<PublicKey>, entropy_source: &ES,
 285                 secp_ctx: &Secp256k1<T>
 286         ) -> Result<Vec<BlindedPath>, ()>;
 287 }
 288
 289 /// A [`MessageRouter`] that can only route to a directly connected [`Destination`].
 290 pub struct DefaultMessageRouter<G: Deref<Target=NetworkGraph<L>>, L: Deref>
 291 where
 292         L::Target: Logger,
 293 {
 294         network_graph: G,
 295 }
 296
 297 impl<G: Deref<Target=NetworkGraph<L>>, L: Deref> DefaultMessageRouter<G, L>
 298 where
 299         L::Target: Logger,
 300 {
 301         /// Creates a [`DefaultMessageRouter`] using the given [`NetworkGraph`].
 302         pub fn new(network_graph: G) -> Self {
 303                 Self { network_graph }
 304         }
 305 }
 306
 307 impl<G: Deref<Target=NetworkGraph<L>>, L: Deref> MessageRouter for DefaultMessageRouter<G, L>
 308 where
 309         L::Target: Logger,
 310 {
 311         fn find_path(
 312                 &self, _sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
 313         ) -> Result<OnionMessagePath, ()> {
 314                 let first_node = destination.first_node();
 315                 if peers.contains(&first_node) {
 316                         Ok(OnionMessagePath {
 317                                 intermediate_nodes: vec![], destination, first_node_addresses: None
 318                         })
 319                 } else {
 320                         let network_graph = self.network_graph.deref().read_only();
 321                         let node_announcement = network_graph
 322                                 .node(&NodeId::from_pubkey(&first_node))
 323                                 .and_then(|node_info| node_info.announcement_info.as_ref())
 324                                 .and_then(|announcement_info| announcement_info.announcement_message.as_ref())
 325                                 .map(|node_announcement| &node_announcement.contents);
 326
 327                         match node_announcement {
 328                                 Some(node_announcement) if node_announcement.features.supports_onion_messages() => {
 329                                         let first_node_addresses = Some(node_announcement.addresses.clone());
 330                                         Ok(OnionMessagePath {
 331                                                 intermediate_nodes: vec![], destination, first_node_addresses
 332                                         })
 333                                 },
 334                                 _ => Err(()),
 335                         }
 336                 }
 337         }
 338
 339         fn create_blinded_paths<
 340                 ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification
 341         >(
 342                 &self, recipient: PublicKey, peers: Vec<PublicKey>, entropy_source: &ES,
 343                 secp_ctx: &Secp256k1<T>
 344         ) -> Result<Vec<BlindedPath>, ()> {
 345                 // Limit the number of blinded paths that are computed.
 346                 const MAX_PATHS: usize = 3;
 347
 348                 // Ensure peers have at least three channels so that it is more difficult to infer the
 349                 // recipient's node_id.
 350                 const MIN_PEER_CHANNELS: usize = 3;
 351
 352                 let network_graph = self.network_graph.deref().read_only();
 353                 let paths = peers.into_iter()
 354                         // Limit to peers with announced channels
 355                         .filter(|pubkey|
 356                                 network_graph
 357                                         .node(&NodeId::from_pubkey(&pubkey))
 358                                         .map(|info| &info.channels[..])
 359                                         .map(|channels| channels.len() >= MIN_PEER_CHANNELS)
 360                                         .unwrap_or(false)
 361                         )
 362                         .map(|pubkey| vec![pubkey, recipient])
 363                         .map(|node_pks| BlindedPath::new_for_message(&node_pks, entropy_source, secp_ctx))
 364                         .take(MAX_PATHS)
 365                         .collect::<Result<Vec<_>, _>>();
 366
 367                 match paths {
 368                         Ok(paths) if !paths.is_empty() => Ok(paths),
 369                         _ => {
 370                                 BlindedPath::one_hop_for_message(recipient, entropy_source, secp_ctx)
 371                                         .map(|path| vec![path])
 372                         },
 373                 }
 374         }
 375 }
 376
 377 /// A path for sending an [`OnionMessage`].
 378 #[derive(Clone)]
 379 pub struct OnionMessagePath {
 380         /// Nodes on the path between the sender and the destination.
 381         pub intermediate_nodes: Vec<PublicKey>,
 382
 383         /// The recipient of the message.
 384         pub destination: Destination,
 385
 386         /// Addresses that may be used to connect to [`OnionMessagePath::first_node`].
 387         ///
 388         /// Only needs to be set if a connection to the node is required. [`OnionMessenger`] may use
 389         /// this to initiate such a connection.
 390         pub first_node_addresses: Option<Vec<SocketAddress>>,
 391 }
 392
 393 impl OnionMessagePath {
 394         /// Returns the first node in the path.
 395         pub fn first_node(&self) -> PublicKey {
 396                 self.intermediate_nodes
 397                         .first()
 398                         .copied()
 399                         .unwrap_or_else(|| self.destination.first_node())
 400         }
 401 }
 402
 403 /// The destination of an onion message.
 404 #[derive(Clone)]
 405 pub enum Destination {
 406         /// We're sending this onion message to a node.
 407         Node(PublicKey),
 408         /// We're sending this onion message to a blinded path.
 409         BlindedPath(BlindedPath),
 410 }
 411
 412 impl Destination {
 413         pub(super) fn num_hops(&self) -> usize {
 414                 match self {
 415                         Destination::Node(_) => 1,
 416                         Destination::BlindedPath(BlindedPath { blinded_hops, .. }) => blinded_hops.len(),
 417                 }
 418         }
 419
 420         fn first_node(&self) -> PublicKey {
 421                 match self {
 422                         Destination::Node(node_id) => *node_id,
 423                         Destination::BlindedPath(BlindedPath { introduction_node_id: node_id, .. }) => *node_id,
 424                 }
 425         }
 426 }
 427
 428 /// Result of successfully [sending an onion message].
 429 ///
 430 /// [sending an onion message]: OnionMessenger::send_onion_message
 431 #[derive(Debug, PartialEq, Eq)]
 432 pub enum SendSuccess {
 433         /// The message was buffered and will be sent once it is processed by
 434         /// [`OnionMessageHandler::next_onion_message_for_peer`].
 435         Buffered,
 436         /// The message was buffered and will be sent once the node is connected as a peer and it is
 437         /// processed by [`OnionMessageHandler::next_onion_message_for_peer`].
 438         BufferedAwaitingConnection(PublicKey),
 439 }
 440
 441 /// Errors that may occur when [sending an onion message].
 442 ///
 443 /// [sending an onion message]: OnionMessenger::send_onion_message
 444 #[derive(Debug, PartialEq, Eq)]
 445 pub enum SendError {
 446         /// Errored computing onion message packet keys.
 447         Secp256k1(secp256k1::Error),
 448         /// Because implementations such as Eclair will drop onion messages where the message packet
 449         /// exceeds 32834 bytes, we refuse to send messages where the packet exceeds this size.
 450         TooBigPacket,
 451         /// The provided [`Destination`] was an invalid [`BlindedPath`] due to not having any blinded
 452         /// hops.
 453         TooFewBlindedHops,
 454         /// The first hop is not a peer and doesn't have a known [`SocketAddress`].
 455         InvalidFirstHop(PublicKey),
 456         /// A path from the sender to the destination could not be found by the [`MessageRouter`].
 457         PathNotFound,
 458         /// Onion message contents must have a TLV type >= 64.
 459         InvalidMessage,
 460         /// Our next-hop peer's buffer was full or our total outbound buffer was full.
 461         BufferFull,
 462         /// Failed to retrieve our node id from the provided [`NodeSigner`].
 463         ///
 464         /// [`NodeSigner`]: crate::sign::NodeSigner
 465         GetNodeIdFailed,
 466         /// We attempted to send to a blinded path where we are the introduction node, and failed to
 467         /// advance the blinded path to make the second hop the new introduction node. Either
 468         /// [`NodeSigner::ecdh`] failed, we failed to tweak the current blinding point to get the
 469         /// new blinding point, or we were attempting to send to ourselves.
 470         BlindedPathAdvanceFailed,
 471 }
 472
 473 /// Handler for custom onion messages. If you are using [`SimpleArcOnionMessenger`],
 474 /// [`SimpleRefOnionMessenger`], or prefer to ignore inbound custom onion messages,
 475 /// [`IgnoringMessageHandler`] must be provided to [`OnionMessenger::new`]. Otherwise, a custom
 476 /// implementation of this trait must be provided, with [`CustomMessage`] specifying the supported
 477 /// message types.
 478 ///
 479 /// See [`OnionMessenger`] for example usage.
 480 ///
 481 /// [`IgnoringMessageHandler`]: crate::ln::peer_handler::IgnoringMessageHandler
 482 /// [`CustomMessage`]: Self::CustomMessage
 483 pub trait CustomOnionMessageHandler {
 484         /// The message known to the handler. To support multiple message types, you may want to make this
 485         /// an enum with a variant for each supported message.
 486         type CustomMessage: OnionMessageContents;
 487
 488         /// Called with the custom message that was received, returning a response to send, if any.
 489         ///
 490         /// The returned [`Self::CustomMessage`], if any, is enqueued to be sent by [`OnionMessenger`].
 491         fn handle_custom_message(&self, msg: Self::CustomMessage) -> Option<Self::CustomMessage>;
 492
 493         /// Read a custom message of type `message_type` from `buffer`, returning `Ok(None)` if the
 494         /// message type is unknown.
 495         fn read_custom_message<R: io::Read>(&self, message_type: u64, buffer: &mut R) -> Result<Option<Self::CustomMessage>, msgs::DecodeError>;
 496
 497         /// Releases any [`Self::CustomMessage`]s that need to be sent.
 498         ///
 499         /// Typically, this is used for messages initiating a message flow rather than in response to
 500         /// another message. The latter should use the return value of [`Self::handle_custom_message`].
 501         #[cfg(not(c_bindings))]
 502         fn release_pending_custom_messages(&self) -> Vec<PendingOnionMessage<Self::CustomMessage>>;
 503
 504         /// Releases any [`Self::CustomMessage`]s that need to be sent.
 505         ///
 506         /// Typically, this is used for messages initiating a message flow rather than in response to
 507         /// another message. The latter should use the return value of [`Self::handle_custom_message`].
 508         #[cfg(c_bindings)]
 509         fn release_pending_custom_messages(&self) -> Vec<(Self::CustomMessage, Destination, Option<BlindedPath>)>;
 510 }
 511
 512 /// A processed incoming onion message, containing either a Forward (another onion message)
 513 /// or a Receive payload with decrypted contents.
 514 pub enum PeeledOnion<T: OnionMessageContents> {
 515         /// Forwarded onion, with the next node id and a new onion
 516         Forward(PublicKey, OnionMessage),
 517         /// Received onion message, with decrypted contents, path_id, and reply path
 518         Receive(ParsedOnionMessageContents<T>, Option<[u8; 32]>, Option<BlindedPath>)
 519 }
 520
 521 /// Creates an [`OnionMessage`] with the given `contents` for sending to the destination of
 522 /// `path`.
 523 ///
 524 /// Returns the node id of the peer to send the message to, the message itself, and any addresses
 525 /// need to connect to the first node.
 526 pub fn create_onion_message<ES: Deref, NS: Deref, T: OnionMessageContents>(
 527         entropy_source: &ES, node_signer: &NS, secp_ctx: &Secp256k1<secp256k1::All>,
 528         path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
 529 ) -> Result<(PublicKey, OnionMessage, Option<Vec<SocketAddress>>), SendError>
 530 where
 531         ES::Target: EntropySource,
 532         NS::Target: NodeSigner,
 533 {
 534         let OnionMessagePath { intermediate_nodes, mut destination, first_node_addresses } = path;
 535         if let Destination::BlindedPath(BlindedPath { ref blinded_hops, .. }) = destination {
 536                 if blinded_hops.is_empty() {
 537                         return Err(SendError::TooFewBlindedHops);
 538                 }
 539         }
 540
 541         if contents.tlv_type() < 64 { return Err(SendError::InvalidMessage) }
 542
 543         // If we are sending straight to a blinded path and we are the introduction node, we need to
 544         // advance the blinded path by 1 hop so the second hop is the new introduction node.
 545         if intermediate_nodes.len() == 0 {
 546                 if let Destination::BlindedPath(ref mut blinded_path) = destination {
 547                         let our_node_id = node_signer.get_node_id(Recipient::Node)
 548                                 .map_err(|()| SendError::GetNodeIdFailed)?;
 549                         if blinded_path.introduction_node_id == our_node_id {
 550                                 advance_path_by_one(blinded_path, node_signer, &secp_ctx)
 551                                         .map_err(|()| SendError::BlindedPathAdvanceFailed)?;
 552                         }
 553                 }
 554         }
 555
 556         let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
 557         let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
 558         let (first_node_id, blinding_point) = if let Some(first_node_id) = intermediate_nodes.first() {
 559                 (*first_node_id, PublicKey::from_secret_key(&secp_ctx, &blinding_secret))
 560         } else {
 561                 match destination {
 562                         Destination::Node(pk) => (pk, PublicKey::from_secret_key(&secp_ctx, &blinding_secret)),
 563                         Destination::BlindedPath(BlindedPath { introduction_node_id, blinding_point, .. }) =>
 564                                 (introduction_node_id, blinding_point),
 565                 }
 566         };
 567         let (packet_payloads, packet_keys) = packet_payloads_and_keys(
 568                 &secp_ctx, &intermediate_nodes, destination, contents, reply_path, &blinding_secret)
 569                 .map_err(|e| SendError::Secp256k1(e))?;
 570
 571         let prng_seed = entropy_source.get_secure_random_bytes();
 572         let onion_routing_packet = construct_onion_message_packet(
 573                 packet_payloads, packet_keys, prng_seed).map_err(|()| SendError::TooBigPacket)?;
 574
 575         let message = OnionMessage { blinding_point, onion_routing_packet };
 576         Ok((first_node_id, message, first_node_addresses))
 577 }
 578
 579 /// Decode one layer of an incoming [`OnionMessage`].
 580 ///
 581 /// Returns either the next layer of the onion for forwarding or the decrypted content for the
 582 /// receiver.
 583 pub fn peel_onion_message<NS: Deref, L: Deref, CMH: Deref>(
 584         msg: &OnionMessage, secp_ctx: &Secp256k1<secp256k1::All>, node_signer: NS, logger: L,
 585         custom_handler: CMH,
 586 ) -> Result<PeeledOnion<<<CMH>::Target as CustomOnionMessageHandler>::CustomMessage>, ()>
 587 where
 588         NS::Target: NodeSigner,
 589         L::Target: Logger,
 590         CMH::Target: CustomOnionMessageHandler,
 591 {
 592         let control_tlvs_ss = match node_signer.ecdh(Recipient::Node, &msg.blinding_point, None) {
 593                 Ok(ss) => ss,
 594                 Err(e) =>  {
 595                         log_error!(logger, "Failed to retrieve node secret: {:?}", e);
 596                         return Err(());
 597                 }
 598         };
 599         let onion_decode_ss = {
 600                 let blinding_factor = {
 601                         let mut hmac = HmacEngine::<Sha256>::new(b"blinded_node_id");
 602                         hmac.input(control_tlvs_ss.as_ref());
 603                         Hmac::from_engine(hmac).to_byte_array()
 604                 };
 605                 match node_signer.ecdh(Recipient::Node, &msg.onion_routing_packet.public_key,
 606                         Some(&Scalar::from_be_bytes(blinding_factor).unwrap()))
 607                 {
 608                         Ok(ss) => ss.secret_bytes(),
 609                         Err(()) => {
 610                                 log_trace!(logger, "Failed to compute onion packet shared secret");
 611                                 return Err(());
 612                         }
 613                 }
 614         };
 615         match onion_utils::decode_next_untagged_hop(
 616                 onion_decode_ss, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
 617                 (control_tlvs_ss, custom_handler.deref(), logger.deref())
 618         ) {
 619                 Ok((Payload::Receive::<ParsedOnionMessageContents<<<CMH as Deref>::Target as CustomOnionMessageHandler>::CustomMessage>> {
 620                         message, control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id }), reply_path,
 621                 }, None)) => {
 622                         Ok(PeeledOnion::Receive(message, path_id, reply_path))
 623                 },
 624                 Ok((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
 625                         next_node_id, next_blinding_override
 626                 })), Some((next_hop_hmac, new_packet_bytes)))) => {
 627                         // TODO: we need to check whether `next_node_id` is our node, in which case this is a dummy
 628                         // blinded hop and this onion message is destined for us. In this situation, we should keep
 629                         // unwrapping the onion layers to get to the final payload. Since we don't have the option
 630                         // of creating blinded paths with dummy hops currently, we should be ok to not handle this
 631                         // for now.
 632                         let new_pubkey = match onion_utils::next_hop_pubkey(&secp_ctx, msg.onion_routing_packet.public_key, &onion_decode_ss) {
 633                                 Ok(pk) => pk,
 634                                 Err(e) => {
 635                                         log_trace!(logger, "Failed to compute next hop packet pubkey: {}", e);
 636                                         return Err(())
 637                                 }
 638                         };
 639                         let outgoing_packet = Packet {
 640                                 version: 0,
 641                                 public_key: new_pubkey,
 642                                 hop_data: new_packet_bytes,
 643                                 hmac: next_hop_hmac,
 644                         };
 645                         let onion_message = OnionMessage {
 646                                 blinding_point: match next_blinding_override {
 647                                         Some(blinding_point) => blinding_point,
 648                                         None => {
 649                                                 match onion_utils::next_hop_pubkey(
 650                                                         &secp_ctx, msg.blinding_point, control_tlvs_ss.as_ref()
 651                                                 ) {
 652                                                         Ok(bp) => bp,
 653                                                         Err(e) => {
 654                                                                 log_trace!(logger, "Failed to compute next blinding point: {}", e);
 655                                                                 return Err(())
 656                                                         }
 657                                                 }
 658                                         }
 659                                 },
 660                                 onion_routing_packet: outgoing_packet,
 661                         };
 662
 663                         Ok(PeeledOnion::Forward(next_node_id, onion_message))
 664                 },
 665                 Err(e) => {
 666                         log_trace!(logger, "Errored decoding onion message packet: {:?}", e);
 667                         Err(())
 668                 },
 669                 _ => {
 670                         log_trace!(logger, "Received bogus onion message packet, either the sender encoded a final hop as a forwarding hop or vice versa");
 671                         Err(())
 672                 },
 673         }
 674 }
 675
 676 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref>
 677 OnionMessenger<ES, NS, L, MR, OMH, CMH>
 678 where
 679         ES::Target: EntropySource,
 680         NS::Target: NodeSigner,
 681         L::Target: Logger,
 682         MR::Target: MessageRouter,
 683         OMH::Target: OffersMessageHandler,
 684         CMH::Target: CustomOnionMessageHandler,
 685 {
 686         /// Constructs a new `OnionMessenger` to send, forward, and delegate received onion messages to
 687         /// their respective handlers.
 688         pub fn new(
 689                 entropy_source: ES, node_signer: NS, logger: L, message_router: MR, offers_handler: OMH,
 690                 custom_handler: CMH
 691         ) -> Self {
 692                 let mut secp_ctx = Secp256k1::new();
 693                 secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
 694                 OnionMessenger {
 695                         entropy_source,
 696                         node_signer,
 697                         message_recipients: Mutex::new(HashMap::new()),
 698                         secp_ctx,
 699                         logger,
 700                         message_router,
 701                         offers_handler,
 702                         custom_handler,
 703                 }
 704         }
 705
 706         /// Sends an [`OnionMessage`] with the given `contents` to `destination`.
 707         ///
 708         /// See [`OnionMessenger`] for example usage.
 709         pub fn send_onion_message<T: OnionMessageContents>(
 710                 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>
 711         ) -> Result<SendSuccess, SendError> {
 712                 self.find_path_and_enqueue_onion_message(
 713                         contents, destination, reply_path, format_args!("")
 714                 )
 715         }
 716
 717         fn find_path_and_enqueue_onion_message<T: OnionMessageContents>(
 718                 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>,
 719                 log_suffix: fmt::Arguments
 720         ) -> Result<SendSuccess, SendError> {
 721                 let result = self.find_path(destination)
 722                         .and_then(|path| self.enqueue_onion_message(path, contents, reply_path, log_suffix));
 723
 724                 match result.as_ref() {
 725                         Err(SendError::GetNodeIdFailed) => {
 726                                 log_warn!(self.logger, "Unable to retrieve node id {}", log_suffix);
 727                         },
 728                         Err(SendError::PathNotFound) => {
 729                                 log_trace!(self.logger, "Failed to find path {}", log_suffix);
 730                         },
 731                         Err(e) => {
 732                                 log_trace!(self.logger, "Failed sending onion message {}: {:?}", log_suffix, e);
 733                         },
 734                         Ok(SendSuccess::Buffered) => {
 735                                 log_trace!(self.logger, "Buffered onion message {}", log_suffix);
 736                         },
 737                         Ok(SendSuccess::BufferedAwaitingConnection(node_id)) => {
 738                                 log_trace!(
 739                                         self.logger, "Buffered onion message waiting on peer connection {}: {:?}",
 740                                         log_suffix, node_id
 741                                 );
 742                         },
 743                 }
 744
 745                 result
 746         }
 747
 748         fn find_path(&self, destination: Destination) -> Result<OnionMessagePath, SendError> {
 749                 let sender = self.node_signer
 750                         .get_node_id(Recipient::Node)
 751                         .map_err(|_| SendError::GetNodeIdFailed)?;
 752
 753                 let peers = self.message_recipients.lock().unwrap()
 754                         .iter()
 755                         .filter(|(_, recipient)| matches!(recipient, OnionMessageRecipient::ConnectedPeer(_)))
 756                         .map(|(node_id, _)| *node_id)
 757                         .collect();
 758
 759                 self.message_router
 760                         .find_path(sender, peers, destination)
 761                         .map_err(|_| SendError::PathNotFound)
 762         }
 763
 764         fn enqueue_onion_message<T: OnionMessageContents>(
 765                 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
 766                 log_suffix: fmt::Arguments
 767         ) -> Result<SendSuccess, SendError> {
 768                 log_trace!(self.logger, "Constructing onion message {}: {:?}", log_suffix, contents);
 769
 770                 let (first_node_id, onion_message, addresses) = create_onion_message(
 771                         &self.entropy_source, &self.node_signer, &self.secp_ctx, path, contents, reply_path
 772                 )?;
 773
 774                 let mut message_recipients = self.message_recipients.lock().unwrap();
 775                 if outbound_buffer_full(&first_node_id, &message_recipients) {
 776                         return Err(SendError::BufferFull);
 777                 }
 778
 779                 match message_recipients.entry(first_node_id) {
 780                         hash_map::Entry::Vacant(e) => match addresses {
 781                                 None => Err(SendError::InvalidFirstHop(first_node_id)),
 782                                 Some(addresses) => {
 783                                         e.insert(OnionMessageRecipient::pending_connection(addresses))
 784                                                 .enqueue_message(onion_message);
 785                                         Ok(SendSuccess::BufferedAwaitingConnection(first_node_id))
 786                                 },
 787                         },
 788                         hash_map::Entry::Occupied(mut e) => {
 789                                 e.get_mut().enqueue_message(onion_message);
 790                                 if e.get().is_connected() {
 791                                         Ok(SendSuccess::Buffered)
 792                                 } else {
 793                                         Ok(SendSuccess::BufferedAwaitingConnection(first_node_id))
 794                                 }
 795                         },
 796                 }
 797         }
 798
 799         #[cfg(test)]
 800         pub(super) fn send_onion_message_using_path<T: OnionMessageContents>(
 801                 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>
 802         ) -> Result<SendSuccess, SendError> {
 803                 self.enqueue_onion_message(path, contents, reply_path, format_args!(""))
 804         }
 805
 806         fn handle_onion_message_response<T: OnionMessageContents>(
 807                 &self, response: Option<T>, reply_path: Option<BlindedPath>, log_suffix: fmt::Arguments
 808         ) {
 809                 if let Some(response) = response {
 810                         match reply_path {
 811                                 Some(reply_path) => {
 812                                         let _ = self.find_path_and_enqueue_onion_message(
 813                                                 response, Destination::BlindedPath(reply_path), None, log_suffix
 814                                         );
 815                                 },
 816                                 None => {
 817                                         log_trace!(self.logger, "Missing reply path {}", log_suffix);
 818                                 },
 819                         }
 820                 }
 821         }
 822
 823         #[cfg(test)]
 824         pub(super) fn release_pending_msgs(&self) -> HashMap<PublicKey, VecDeque<OnionMessage>> {
 825                 let mut message_recipients = self.message_recipients.lock().unwrap();
 826                 let mut msgs = HashMap::new();
 827                 // We don't want to disconnect the peers by removing them entirely from the original map, so we
 828                 // release the pending message buffers individually.
 829                 for (node_id, recipient) in &mut *message_recipients {
 830                         msgs.insert(*node_id, recipient.release_pending_messages());
 831                 }
 832                 msgs
 833         }
 834 }
 835
 836 fn outbound_buffer_full(peer_node_id: &PublicKey, buffer: &HashMap<PublicKey, OnionMessageRecipient>) -> bool {
 837         const MAX_TOTAL_BUFFER_SIZE: usize = (1 << 20) * 128;
 838         const MAX_PER_PEER_BUFFER_SIZE: usize = (1 << 10) * 256;
 839         let mut total_buffered_bytes = 0;
 840         let mut peer_buffered_bytes = 0;
 841         for (pk, peer_buf) in buffer {
 842                 for om in peer_buf.pending_messages() {
 843                         let om_len = om.serialized_length();
 844                         if pk == peer_node_id {
 845                                 peer_buffered_bytes += om_len;
 846                         }
 847                         total_buffered_bytes += om_len;
 848
 849                         if total_buffered_bytes >= MAX_TOTAL_BUFFER_SIZE ||
 850                                 peer_buffered_bytes >= MAX_PER_PEER_BUFFER_SIZE
 851                         {
 852                                 return true
 853                         }
 854                 }
 855         }
 856         false
 857 }
 858
 859 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref> EventsProvider
 860 for OnionMessenger<ES, NS, L, MR, OMH, CMH>
 861 where
 862         ES::Target: EntropySource,
 863         NS::Target: NodeSigner,
 864         L::Target: Logger,
 865         MR::Target: MessageRouter,
 866         OMH::Target: OffersMessageHandler,
 867         CMH::Target: CustomOnionMessageHandler,
 868 {
 869         fn process_pending_events<H: Deref>(&self, handler: H) where H::Target: EventHandler {
 870                 for (node_id, recipient) in self.message_recipients.lock().unwrap().iter_mut() {
 871                         if let OnionMessageRecipient::PendingConnection(_, addresses, _) = recipient {
 872                                 if let Some(addresses) = addresses.take() {
 873                                         handler.handle_event(Event::ConnectionNeeded { node_id: *node_id, addresses });
 874                                 }
 875                         }
 876                 }
 877         }
 878 }
 879
 880 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref> OnionMessageHandler
 881 for OnionMessenger<ES, NS, L, MR, OMH, CMH>
 882 where
 883         ES::Target: EntropySource,
 884         NS::Target: NodeSigner,
 885         L::Target: Logger,
 886         MR::Target: MessageRouter,
 887         OMH::Target: OffersMessageHandler,
 888         CMH::Target: CustomOnionMessageHandler,
 889 {
 890         fn handle_onion_message(&self, _peer_node_id: &PublicKey, msg: &OnionMessage) {
 891                 match peel_onion_message(
 892                         msg, &self.secp_ctx, &*self.node_signer, &*self.logger, &*self.custom_handler
 893                 ) {
 894                         Ok(PeeledOnion::Receive(message, path_id, reply_path)) => {
 895                                 log_trace!(
 896                                         self.logger,
 897                                    "Received an onion message with path_id {:02x?} and {} reply_path: {:?}",
 898                                         path_id, if reply_path.is_some() { "a" } else { "no" }, message);
 899
 900                                 match message {
 901                                         ParsedOnionMessageContents::Offers(msg) => {
 902                                                 let response = self.offers_handler.handle_message(msg);
 903                                                 self.handle_onion_message_response(
 904                                                         response, reply_path, format_args!(
 905                                                                 "when responding to Offers onion message with path_id {:02x?}",
 906                                                                 path_id
 907                                                         )
 908                                                 );
 909                                         },
 910                                         ParsedOnionMessageContents::Custom(msg) => {
 911                                                 let response = self.custom_handler.handle_custom_message(msg);
 912                                                 self.handle_onion_message_response(
 913                                                         response, reply_path, format_args!(
 914                                                                 "when responding to Custom onion message with path_id {:02x?}",
 915                                                                 path_id
 916                                                         )
 917                                                 );
 918                                         },
 919                                 }
 920                         },
 921                         Ok(PeeledOnion::Forward(next_node_id, onion_message)) => {
 922                                 let mut message_recipients = self.message_recipients.lock().unwrap();
 923                                 if outbound_buffer_full(&next_node_id, &message_recipients) {
 924                                         log_trace!(self.logger, "Dropping forwarded onion message to peer {:?}: outbound buffer full", next_node_id);
 925                                         return
 926                                 }
 927
 928                                 #[cfg(fuzzing)]
 929                                 message_recipients
 930                                         .entry(next_node_id)
 931                                         .or_insert_with(|| OnionMessageRecipient::ConnectedPeer(VecDeque::new()));
 932
 933                                 match message_recipients.entry(next_node_id) {
 934                                         hash_map::Entry::Occupied(mut e) if matches!(
 935                                                 e.get(), OnionMessageRecipient::ConnectedPeer(..)
 936                                         ) => {
 937                                                 e.get_mut().enqueue_message(onion_message);
 938                                                 log_trace!(self.logger, "Forwarding an onion message to peer {}", next_node_id);
 939                                         },
 940                                         _ => {
 941                                                 log_trace!(self.logger, "Dropping forwarded onion message to disconnected peer {:?}", next_node_id);
 942                                                 return
 943                                         },
 944                                 }
 945                         },
 946                         Err(e) => {
 947                                 log_error!(self.logger, "Failed to process onion message {:?}", e);
 948                         }
 949                 }
 950         }
 951
 952         fn peer_connected(&self, their_node_id: &PublicKey, init: &msgs::Init, _inbound: bool) -> Result<(), ()> {
 953                 if init.features.supports_onion_messages() {
 954                         self.message_recipients.lock().unwrap()
 955                                 .entry(*their_node_id)
 956                                 .or_insert_with(|| OnionMessageRecipient::ConnectedPeer(VecDeque::new()))
 957                                 .mark_connected();
 958                 } else {
 959                         self.message_recipients.lock().unwrap().remove(their_node_id);
 960                 }
 961
 962                 Ok(())
 963         }
 964
 965         fn peer_disconnected(&self, their_node_id: &PublicKey) {
 966                 match self.message_recipients.lock().unwrap().remove(their_node_id) {
 967                         Some(OnionMessageRecipient::ConnectedPeer(..)) => {},
 968                         Some(_) => debug_assert!(false),
 969                         None => {},
 970                 }
 971         }
 972
 973         fn timer_tick_occurred(&self) {
 974                 let mut message_recipients = self.message_recipients.lock().unwrap();
 975
 976                 // Drop any pending recipients since the last call to avoid retaining buffered messages for
 977                 // too long.
 978                 message_recipients.retain(|_, recipient| match recipient {
 979                         OnionMessageRecipient::PendingConnection(_, None, ticks) => *ticks < MAX_TIMER_TICKS,
 980                         OnionMessageRecipient::PendingConnection(_, Some(_), _) => true,
 981                         _ => true,
 982                 });
 983
 984                 // Increment a timer tick for pending recipients so that their buffered messages are dropped
 985                 // at MAX_TIMER_TICKS.
 986                 for recipient in message_recipients.values_mut() {
 987                         if let OnionMessageRecipient::PendingConnection(_, None, ticks) = recipient {
 988                                 *ticks += 1;
 989                         }
 990                 }
 991         }
 992
 993         fn provided_node_features(&self) -> NodeFeatures {
 994                 let mut features = NodeFeatures::empty();
 995                 features.set_onion_messages_optional();
 996                 features
 997         }
 998
 999         fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
1000                 let mut features = InitFeatures::empty();
1001                 features.set_onion_messages_optional();
1002                 features
1003         }
1004
1005         // Before returning any messages to send for the peer, this method will see if any messages were
1006         // enqueued in the handler by users, find a path to the corresponding blinded path's introduction
1007         // node, and then enqueue the message for sending to the first peer in the full path.
1008         fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<OnionMessage> {
1009                 // Enqueue any initiating `OffersMessage`s to send.
1010                 for message in self.offers_handler.release_pending_messages() {
1011                         #[cfg(not(c_bindings))]
1012                         let PendingOnionMessage { contents, destination, reply_path } = message;
1013                         #[cfg(c_bindings)]
1014                         let (contents, destination, reply_path) = message;
1015                         let _ = self.find_path_and_enqueue_onion_message(
1016                                 contents, destination, reply_path, format_args!("when sending OffersMessage")
1017                         );
1018                 }
1019
1020                 // Enqueue any initiating `CustomMessage`s to send.
1021                 for message in self.custom_handler.release_pending_custom_messages() {
1022                         #[cfg(not(c_bindings))]
1023                         let PendingOnionMessage { contents, destination, reply_path } = message;
1024                         #[cfg(c_bindings)]
1025                         let (contents, destination, reply_path) = message;
1026                         let _ = self.find_path_and_enqueue_onion_message(
1027                                 contents, destination, reply_path, format_args!("when sending CustomMessage")
1028                         );
1029                 }
1030
1031                 self.message_recipients.lock().unwrap()
1032                         .get_mut(&peer_node_id)
1033                         .and_then(|buffer| buffer.dequeue_message())
1034         }
1035 }
1036
1037 // TODO: parameterize the below Simple* types with OnionMessenger and handle the messages it
1038 // produces
1039 /// Useful for simplifying the parameters of [`SimpleArcChannelManager`] and
1040 /// [`SimpleArcPeerManager`]. See their docs for more details.
1041 ///
1042 /// This is not exported to bindings users as type aliases aren't supported in most languages.
1043 ///
1044 /// [`SimpleArcChannelManager`]: crate::ln::channelmanager::SimpleArcChannelManager
1045 /// [`SimpleArcPeerManager`]: crate::ln::peer_handler::SimpleArcPeerManager
1046 #[cfg(not(c_bindings))]
1047 pub type SimpleArcOnionMessenger<M, T, F, L> = OnionMessenger<
1048         Arc<KeysManager>,
1049         Arc<KeysManager>,
1050         Arc<L>,
1051         Arc<DefaultMessageRouter<Arc<NetworkGraph<Arc<L>>>, Arc<L>>>,
1052         Arc<SimpleArcChannelManager<M, T, F, L>>,
1053         IgnoringMessageHandler
1054 >;
1055
1056 /// Useful for simplifying the parameters of [`SimpleRefChannelManager`] and
1057 /// [`SimpleRefPeerManager`]. See their docs for more details.
1058 ///
1059 /// This is not exported to bindings users as type aliases aren't supported in most languages.
1060 ///
1061 /// [`SimpleRefChannelManager`]: crate::ln::channelmanager::SimpleRefChannelManager
1062 /// [`SimpleRefPeerManager`]: crate::ln::peer_handler::SimpleRefPeerManager
1063 #[cfg(not(c_bindings))]
1064 pub type SimpleRefOnionMessenger<
1065         'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, 'i, 'j, M, T, F, L
1066 > = OnionMessenger<
1067         &'a KeysManager,
1068         &'a KeysManager,
1069         &'b L,
1070         &'i DefaultMessageRouter<&'g NetworkGraph<&'b L>, &'b L>,
1071         &'j SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, M, T, F, L>,
1072         IgnoringMessageHandler
1073 >;
1074
1075 /// Construct onion packet payloads and keys for sending an onion message along the given
1076 /// `unblinded_path` to the given `destination`.
1077 fn packet_payloads_and_keys<T: OnionMessageContents, S: secp256k1::Signing + secp256k1::Verification>(
1078         secp_ctx: &Secp256k1<S>, unblinded_path: &[PublicKey], destination: Destination, message: T,
1079         mut reply_path: Option<BlindedPath>, session_priv: &SecretKey
1080 ) -> Result<(Vec<(Payload<T>, [u8; 32])>, Vec<onion_utils::OnionKeys>), secp256k1::Error> {
1081         let num_hops = unblinded_path.len() + destination.num_hops();
1082         let mut payloads = Vec::with_capacity(num_hops);
1083         let mut onion_packet_keys = Vec::with_capacity(num_hops);
1084
1085         let (mut intro_node_id_blinding_pt, num_blinded_hops) = if let Destination::BlindedPath(BlindedPath {
1086                 introduction_node_id, blinding_point, blinded_hops }) = &destination {
1087                 (Some((*introduction_node_id, *blinding_point)), blinded_hops.len()) } else { (None, 0) };
1088         let num_unblinded_hops = num_hops - num_blinded_hops;
1089
1090         let mut unblinded_path_idx = 0;
1091         let mut blinded_path_idx = 0;
1092         let mut prev_control_tlvs_ss = None;
1093         let mut final_control_tlvs = None;
1094         utils::construct_keys_callback(secp_ctx, unblinded_path.iter(), Some(destination), session_priv,
1095                 |_, onion_packet_ss, ephemeral_pubkey, control_tlvs_ss, unblinded_pk_opt, enc_payload_opt| {
1096                         if num_unblinded_hops != 0 && unblinded_path_idx < num_unblinded_hops {
1097                                 if let Some(ss) = prev_control_tlvs_ss.take() {
1098                                         payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(
1099                                                 ForwardTlvs {
1100                                                         next_node_id: unblinded_pk_opt.unwrap(),
1101                                                         next_blinding_override: None,
1102                                                 }
1103                                         )), ss));
1104                                 }
1105                                 prev_control_tlvs_ss = Some(control_tlvs_ss);
1106                                 unblinded_path_idx += 1;
1107                         } else if let Some((intro_node_id, blinding_pt)) = intro_node_id_blinding_pt.take() {
1108                                 if let Some(control_tlvs_ss) = prev_control_tlvs_ss.take() {
1109                                         payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
1110                                                 next_node_id: intro_node_id,
1111                                                 next_blinding_override: Some(blinding_pt),
1112                                         })), control_tlvs_ss));
1113                                 }
1114                         }
1115                         if blinded_path_idx < num_blinded_hops.saturating_sub(1) && enc_payload_opt.is_some() {
1116                                 payloads.push((Payload::Forward(ForwardControlTlvs::Blinded(enc_payload_opt.unwrap())),
1117                                         control_tlvs_ss));
1118                                 blinded_path_idx += 1;
1119                         } else if let Some(encrypted_payload) = enc_payload_opt {
1120                                 final_control_tlvs = Some(ReceiveControlTlvs::Blinded(encrypted_payload));
1121                                 prev_control_tlvs_ss = Some(control_tlvs_ss);
1122                         }
1123
1124                         let (rho, mu) = onion_utils::gen_rho_mu_from_shared_secret(onion_packet_ss.as_ref());
1125                         onion_packet_keys.push(onion_utils::OnionKeys {
1126                                 #[cfg(test)]
1127                                 shared_secret: onion_packet_ss,
1128                                 #[cfg(test)]
1129                                 blinding_factor: [0; 32],
1130                                 ephemeral_pubkey,
1131                                 rho,
1132                                 mu,
1133                         });
1134                 }
1135         )?;
1136
1137         if let Some(control_tlvs) = final_control_tlvs {
1138                 payloads.push((Payload::Receive {
1139                         control_tlvs,
1140                         reply_path: reply_path.take(),
1141                         message,
1142                 }, prev_control_tlvs_ss.unwrap()));
1143         } else {
1144                 payloads.push((Payload::Receive {
1145                         control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id: None, }),
1146                         reply_path: reply_path.take(),
1147                         message,
1148                 }, prev_control_tlvs_ss.unwrap()));
1149         }
1150
1151         Ok((payloads, onion_packet_keys))
1152 }
1153
1154 /// Errors if the serialized payload size exceeds onion_message::BIG_PACKET_HOP_DATA_LEN
1155 fn construct_onion_message_packet<T: OnionMessageContents>(payloads: Vec<(Payload<T>, [u8; 32])>, onion_keys: Vec<onion_utils::OnionKeys>, prng_seed: [u8; 32]) -> Result<Packet, ()> {
1156         // Spec rationale:
1157         // "`len` allows larger messages to be sent than the standard 1300 bytes allowed for an HTLC
1158         // onion, but this should be used sparingly as it is reduces anonymity set, hence the
1159         // recommendation that it either look like an HTLC onion, or if larger, be a fixed size."
1160         let payloads_ser_len = onion_utils::payloads_serialized_length(&payloads);
1161         let hop_data_len = if payloads_ser_len <= SMALL_PACKET_HOP_DATA_LEN {
1162                 SMALL_PACKET_HOP_DATA_LEN
1163         } else if payloads_ser_len <= BIG_PACKET_HOP_DATA_LEN {
1164                 BIG_PACKET_HOP_DATA_LEN
1165         } else { return Err(()) };
1166
1167         onion_utils::construct_onion_message_packet::<_, _>(
1168                 payloads, onion_keys, prng_seed, hop_data_len)
1169 }