_ 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 this [`OnionMessenger`], which lives here,
  11 //! as well as various types, traits, and utilities that it uses.
  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, IntroductionNode, NextMessageHop, NodeIdLookUp};
  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, NodeSigner, Recipient};
  23 use crate::ln::features::{InitFeatures, NodeFeatures};
  24 use crate::ln::msgs::{self, OnionMessage, OnionMessageHandler, SocketAddress};
  25 use crate::ln::onion_utils;
  26 use crate::routing::gossip::{NetworkGraph, NodeId, ReadOnlyNetworkGraph};
  27 use super::packet::OnionMessageContents;
  28 use super::packet::ParsedOnionMessageContents;
  29 use super::offers::OffersMessageHandler;
  30 use super::packet::{BIG_PACKET_HOP_DATA_LEN, ForwardControlTlvs, Packet, Payload, ReceiveControlTlvs, SMALL_PACKET_HOP_DATA_LEN};
  31 use crate::util::logger::{Logger, WithContext};
  32 use crate::util::ser::Writeable;
  33
  34 use core::fmt;
  35 use core::ops::Deref;
  36 use crate::io;
  37 use crate::sync::Mutex;
  38 use crate::prelude::*;
  39
  40 #[cfg(not(c_bindings))]
  41 use {
  42         crate::sign::KeysManager,
  43         crate::ln::channelmanager::{SimpleArcChannelManager, SimpleRefChannelManager},
  44         crate::ln::peer_handler::IgnoringMessageHandler,
  45         crate::sync::Arc,
  46 };
  47
  48 pub(super) const MAX_TIMER_TICKS: usize = 2;
  49
  50 /// A sender, receiver and forwarder of [`OnionMessage`]s.
  51 ///
  52 /// # Handling Messages
  53 ///
  54 /// `OnionMessenger` implements [`OnionMessageHandler`], making it responsible for either forwarding
  55 /// messages to peers or delegating to the appropriate handler for the message type. Currently, the
  56 /// available handlers are:
  57 /// * [`OffersMessageHandler`], for responding to [`InvoiceRequest`]s and paying [`Bolt12Invoice`]s
  58 /// * [`CustomOnionMessageHandler`], for handling user-defined message types
  59 ///
  60 /// # Sending Messages
  61 ///
  62 /// [`OnionMessage`]s are sent initially using [`OnionMessenger::send_onion_message`]. When handling
  63 /// a message, the matched handler may return a response message which `OnionMessenger` will send
  64 /// on its behalf.
  65 ///
  66 /// # Example
  67 ///
  68 /// ```
  69 /// # extern crate bitcoin;
  70 /// # use bitcoin::hashes::_export::_core::time::Duration;
  71 /// # use bitcoin::hashes::hex::FromHex;
  72 /// # use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey, self};
  73 /// # use lightning::blinded_path::{BlindedPath, EmptyNodeIdLookUp};
  74 /// # use lightning::sign::{EntropySource, KeysManager};
  75 /// # use lightning::ln::peer_handler::IgnoringMessageHandler;
  76 /// # use lightning::onion_message::messenger::{Destination, MessageRouter, OnionMessagePath, OnionMessenger};
  77 /// # use lightning::onion_message::packet::OnionMessageContents;
  78 /// # use lightning::util::logger::{Logger, Record};
  79 /// # use lightning::util::ser::{Writeable, Writer};
  80 /// # use lightning::io;
  81 /// # use std::sync::Arc;
  82 /// # struct FakeLogger;
  83 /// # impl Logger for FakeLogger {
  84 /// #     fn log(&self, record: Record) { println!("{:?}" , record); }
  85 /// # }
  86 /// # struct FakeMessageRouter {}
  87 /// # impl MessageRouter for FakeMessageRouter {
  88 /// #     fn find_path(&self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination) -> Result<OnionMessagePath, ()> {
  89 /// #         let secp_ctx = Secp256k1::new();
  90 /// #         let node_secret = SecretKey::from_slice(&<Vec<u8>>::from_hex("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
  91 /// #         let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
  92 /// #         let hop_node_id2 = hop_node_id1;
  93 /// #         Ok(OnionMessagePath {
  94 /// #             intermediate_nodes: vec![hop_node_id1, hop_node_id2],
  95 /// #             destination,
  96 /// #             first_node_addresses: None,
  97 /// #         })
  98 /// #     }
  99 /// #     fn create_blinded_paths<T: secp256k1::Signing + secp256k1::Verification>(
 100 /// #         &self, _recipient: PublicKey, _peers: Vec<PublicKey>, _secp_ctx: &Secp256k1<T>
 101 /// #     ) -> Result<Vec<BlindedPath>, ()> {
 102 /// #         unreachable!()
 103 /// #     }
 104 /// # }
 105 /// # let seed = [42u8; 32];
 106 /// # let time = Duration::from_secs(123456);
 107 /// # let keys_manager = KeysManager::new(&seed, time.as_secs(), time.subsec_nanos());
 108 /// # let logger = Arc::new(FakeLogger {});
 109 /// # let node_secret = SecretKey::from_slice(&<Vec<u8>>::from_hex("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
 110 /// # let secp_ctx = Secp256k1::new();
 111 /// # let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
 112 /// # let (hop_node_id3, hop_node_id4) = (hop_node_id1, hop_node_id1);
 113 /// # let destination_node_id = hop_node_id1;
 114 /// # let node_id_lookup = EmptyNodeIdLookUp {};
 115 /// # let message_router = Arc::new(FakeMessageRouter {});
 116 /// # let custom_message_handler = IgnoringMessageHandler {};
 117 /// # let offers_message_handler = IgnoringMessageHandler {};
 118 /// // Create the onion messenger. This must use the same `keys_manager` as is passed to your
 119 /// // ChannelManager.
 120 /// let onion_messenger = OnionMessenger::new(
 121 ///     &keys_manager, &keys_manager, logger, &node_id_lookup, message_router,
 122 ///     &offers_message_handler, &custom_message_handler
 123 /// );
 124
 125 /// # #[derive(Debug)]
 126 /// # struct YourCustomMessage {}
 127 /// impl Writeable for YourCustomMessage {
 128 ///     fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
 129 ///             # Ok(())
 130 ///             // Write your custom onion message to `w`
 131 ///     }
 132 /// }
 133 /// impl OnionMessageContents for YourCustomMessage {
 134 ///     fn tlv_type(&self) -> u64 {
 135 ///             # let your_custom_message_type = 42;
 136 ///             your_custom_message_type
 137 ///     }
 138 ///     fn msg_type(&self) -> &'static str { "YourCustomMessageType" }
 139 /// }
 140 /// // Send a custom onion message to a node id.
 141 /// let destination = Destination::Node(destination_node_id);
 142 /// let reply_path = None;
 143 /// # let message = YourCustomMessage {};
 144 /// onion_messenger.send_onion_message(message, destination, reply_path);
 145 ///
 146 /// // Create a blinded path to yourself, for someone to send an onion message to.
 147 /// # let your_node_id = hop_node_id1;
 148 /// let hops = [hop_node_id3, hop_node_id4, your_node_id];
 149 /// let blinded_path = BlindedPath::new_for_message(&hops, &keys_manager, &secp_ctx).unwrap();
 150 ///
 151 /// // Send a custom onion message to a blinded path.
 152 /// let destination = Destination::BlindedPath(blinded_path);
 153 /// let reply_path = None;
 154 /// # let message = YourCustomMessage {};
 155 /// onion_messenger.send_onion_message(message, destination, reply_path);
 156 /// ```
 157 ///
 158 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
 159 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 160 pub struct OnionMessenger<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, CMH: Deref>
 161 where
 162         ES::Target: EntropySource,
 163         NS::Target: NodeSigner,
 164         L::Target: Logger,
 165         NL::Target: NodeIdLookUp,
 166         MR::Target: MessageRouter,
 167         OMH::Target: OffersMessageHandler,
 168         CMH::Target: CustomOnionMessageHandler,
 169 {
 170         entropy_source: ES,
 171         node_signer: NS,
 172         logger: L,
 173         message_recipients: Mutex<HashMap<PublicKey, OnionMessageRecipient>>,
 174         secp_ctx: Secp256k1<secp256k1::All>,
 175         node_id_lookup: NL,
 176         message_router: MR,
 177         offers_handler: OMH,
 178         custom_handler: CMH,
 179 }
 180
 181 /// [`OnionMessage`]s buffered to be sent.
 182 enum OnionMessageRecipient {
 183         /// Messages for a node connected as a peer.
 184         ConnectedPeer(VecDeque<OnionMessage>),
 185
 186         /// Messages for a node that is not yet connected, which are dropped after [`MAX_TIMER_TICKS`]
 187         /// and tracked here.
 188         PendingConnection(VecDeque<OnionMessage>, Option<Vec<SocketAddress>>, usize),
 189 }
 190
 191 impl OnionMessageRecipient {
 192         fn pending_connection(addresses: Vec<SocketAddress>) -> Self {
 193                 Self::PendingConnection(VecDeque::new(), Some(addresses), 0)
 194         }
 195
 196         fn pending_messages(&self) -> &VecDeque<OnionMessage> {
 197                 match self {
 198                         OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
 199                         OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
 200                 }
 201         }
 202
 203         fn enqueue_message(&mut self, message: OnionMessage) {
 204                 let pending_messages = match self {
 205                         OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
 206                         OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
 207                 };
 208
 209                 pending_messages.push_back(message);
 210         }
 211
 212         fn dequeue_message(&mut self) -> Option<OnionMessage> {
 213                 let pending_messages = match self {
 214                         OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
 215                         OnionMessageRecipient::PendingConnection(pending_messages, _, _) => {
 216                                 debug_assert!(false);
 217                                 pending_messages
 218                         },
 219                 };
 220
 221                 pending_messages.pop_front()
 222         }
 223
 224         #[cfg(test)]
 225         fn release_pending_messages(&mut self) -> VecDeque<OnionMessage> {
 226                 let pending_messages = match self {
 227                         OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
 228                         OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
 229                 };
 230
 231                 core::mem::take(pending_messages)
 232         }
 233
 234         fn mark_connected(&mut self) {
 235                 if let OnionMessageRecipient::PendingConnection(pending_messages, _, _) = self {
 236                         let mut new_pending_messages = VecDeque::new();
 237                         core::mem::swap(pending_messages, &mut new_pending_messages);
 238                         *self = OnionMessageRecipient::ConnectedPeer(new_pending_messages);
 239                 }
 240         }
 241
 242         fn is_connected(&self) -> bool {
 243                 match self {
 244                         OnionMessageRecipient::ConnectedPeer(..) => true,
 245                         OnionMessageRecipient::PendingConnection(..) => false,
 246                 }
 247         }
 248 }
 249
 250
 251 /// The `Responder` struct creates an appropriate [`ResponseInstruction`]
 252 /// for responding to a message.
 253 pub struct Responder {
 254         /// The path along which a response can be sent.
 255         reply_path: BlindedPath,
 256         path_id: Option<[u8; 32]>
 257 }
 258
 259 impl Responder {
 260         /// Creates a new [`Responder`] instance with the provided reply path.
 261         fn new(reply_path: BlindedPath, path_id: Option<[u8; 32]>) -> Self {
 262                 Responder {
 263                         reply_path,
 264                         path_id,
 265                 }
 266         }
 267
 268         /// Creates the appropriate [`ResponseInstruction`] for a given response.
 269         pub fn respond<T: OnionMessageContents>(self, response: T) -> ResponseInstruction<T> {
 270                 ResponseInstruction::WithoutReplyPath(OnionMessageResponse {
 271                         message: response,
 272                         reply_path: self.reply_path,
 273                         path_id: self.path_id,
 274                 })
 275         }
 276 }
 277
 278 /// This struct contains the information needed to reply to a received message.
 279 pub struct OnionMessageResponse<T: OnionMessageContents> {
 280         message: T,
 281         reply_path: BlindedPath,
 282         path_id: Option<[u8; 32]>,
 283 }
 284
 285 /// `ResponseInstruction` represents instructions for responding to received messages.
 286 pub enum ResponseInstruction<T: OnionMessageContents> {
 287         /// Indicates that a response should be sent without including a reply path
 288         /// for the recipient to respond back.
 289         WithoutReplyPath(OnionMessageResponse<T>),
 290         /// Indicates that there's no response to send back.
 291         NoResponse,
 292 }
 293
 294 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
 295 ///
 296 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
 297 /// enqueued for sending.
 298 #[cfg(not(c_bindings))]
 299 pub struct PendingOnionMessage<T: OnionMessageContents> {
 300         /// The message contents to send in an [`OnionMessage`].
 301         pub contents: T,
 302
 303         /// The destination of the message.
 304         pub destination: Destination,
 305
 306         /// A reply path to include in the [`OnionMessage`] for a response.
 307         pub reply_path: Option<BlindedPath>,
 308 }
 309
 310 #[cfg(c_bindings)]
 311 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
 312 ///
 313 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
 314 /// enqueued for sending.
 315 pub type PendingOnionMessage<T> = (T, Destination, Option<BlindedPath>);
 316
 317 pub(crate) fn new_pending_onion_message<T: OnionMessageContents>(
 318         contents: T, destination: Destination, reply_path: Option<BlindedPath>
 319 ) -> PendingOnionMessage<T> {
 320         #[cfg(not(c_bindings))]
 321         return PendingOnionMessage { contents, destination, reply_path };
 322         #[cfg(c_bindings)]
 323         return (contents, destination, reply_path);
 324 }
 325
 326 /// A trait defining behavior for routing an [`OnionMessage`].
 327 pub trait MessageRouter {
 328         /// Returns a route for sending an [`OnionMessage`] to the given [`Destination`].
 329         fn find_path(
 330                 &self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
 331         ) -> Result<OnionMessagePath, ()>;
 332
 333         /// Creates [`BlindedPath`]s to the `recipient` node. The nodes in `peers` are assumed to be
 334         /// direct peers with the `recipient`.
 335         fn create_blinded_paths<
 336                 T: secp256k1::Signing + secp256k1::Verification
 337         >(
 338                 &self, recipient: PublicKey, peers: Vec<PublicKey>, secp_ctx: &Secp256k1<T>,
 339         ) -> Result<Vec<BlindedPath>, ()>;
 340 }
 341
 342 /// A [`MessageRouter`] that can only route to a directly connected [`Destination`].
 343 pub struct DefaultMessageRouter<G: Deref<Target=NetworkGraph<L>>, L: Deref, ES: Deref>
 344 where
 345         L::Target: Logger,
 346         ES::Target: EntropySource,
 347 {
 348         network_graph: G,
 349         entropy_source: ES,
 350 }
 351
 352 impl<G: Deref<Target=NetworkGraph<L>>, L: Deref, ES: Deref> DefaultMessageRouter<G, L, ES>
 353 where
 354         L::Target: Logger,
 355         ES::Target: EntropySource,
 356 {
 357         /// Creates a [`DefaultMessageRouter`] using the given [`NetworkGraph`].
 358         pub fn new(network_graph: G, entropy_source: ES) -> Self {
 359                 Self { network_graph, entropy_source }
 360         }
 361 }
 362
 363 impl<G: Deref<Target=NetworkGraph<L>>, L: Deref, ES: Deref> MessageRouter for DefaultMessageRouter<G, L, ES>
 364 where
 365         L::Target: Logger,
 366         ES::Target: EntropySource,
 367 {
 368         fn find_path(
 369                 &self, sender: PublicKey, peers: Vec<PublicKey>, mut destination: Destination
 370         ) -> Result<OnionMessagePath, ()> {
 371                 let network_graph = self.network_graph.deref().read_only();
 372                 destination.resolve(&network_graph);
 373
 374                 let first_node = match destination.first_node() {
 375                         Some(first_node) => first_node,
 376                         None => return Err(()),
 377                 };
 378
 379                 if peers.contains(&first_node) || sender == first_node {
 380                         Ok(OnionMessagePath {
 381                                 intermediate_nodes: vec![], destination, first_node_addresses: None
 382                         })
 383                 } else {
 384                         let node_announcement = network_graph
 385                                 .node(&NodeId::from_pubkey(&first_node))
 386                                 .and_then(|node_info| node_info.announcement_info.as_ref())
 387                                 .and_then(|announcement_info| announcement_info.announcement_message.as_ref())
 388                                 .map(|node_announcement| &node_announcement.contents);
 389
 390                         match node_announcement {
 391                                 Some(node_announcement) if node_announcement.features.supports_onion_messages() => {
 392                                         let first_node_addresses = Some(node_announcement.addresses.clone());
 393                                         Ok(OnionMessagePath {
 394                                                 intermediate_nodes: vec![], destination, first_node_addresses
 395                                         })
 396                                 },
 397                                 _ => Err(()),
 398                         }
 399                 }
 400         }
 401
 402         fn create_blinded_paths<
 403                 T: secp256k1::Signing + secp256k1::Verification
 404         >(
 405                 &self, recipient: PublicKey, peers: Vec<PublicKey>, secp_ctx: &Secp256k1<T>,
 406         ) -> Result<Vec<BlindedPath>, ()> {
 407                 // Limit the number of blinded paths that are computed.
 408                 const MAX_PATHS: usize = 3;
 409
 410                 // Ensure peers have at least three channels so that it is more difficult to infer the
 411                 // recipient's node_id.
 412                 const MIN_PEER_CHANNELS: usize = 3;
 413
 414                 let network_graph = self.network_graph.deref().read_only();
 415                 let is_recipient_announced =
 416                         network_graph.nodes().contains_key(&NodeId::from_pubkey(&recipient));
 417
 418                 let mut peer_info = peers.iter()
 419                         // Limit to peers with announced channels
 420                         .filter_map(|pubkey|
 421                                 network_graph
 422                                         .node(&NodeId::from_pubkey(pubkey))
 423                                         .filter(|info| info.channels.len() >= MIN_PEER_CHANNELS)
 424                                         .map(|info| (*pubkey, info.is_tor_only(), info.channels.len()))
 425                         )
 426                         // Exclude Tor-only nodes when the recipient is announced.
 427                         .filter(|(_, is_tor_only, _)| !(*is_tor_only && is_recipient_announced))
 428                         .collect::<Vec<_>>();
 429
 430                 // Prefer using non-Tor nodes with the most channels as the introduction node.
 431                 peer_info.sort_unstable_by(|(_, a_tor_only, a_channels), (_, b_tor_only, b_channels)| {
 432                         a_tor_only.cmp(b_tor_only).then(a_channels.cmp(b_channels).reverse())
 433                 });
 434
 435                 let paths = peer_info.into_iter()
 436                         .map(|(pubkey, _, _)| vec![pubkey, recipient])
 437                         .map(|node_pks| BlindedPath::new_for_message(&node_pks, &*self.entropy_source, secp_ctx))
 438                         .take(MAX_PATHS)
 439                         .collect::<Result<Vec<_>, _>>();
 440
 441                 match paths {
 442                         Ok(paths) if !paths.is_empty() => Ok(paths),
 443                         _ => {
 444                                 if is_recipient_announced {
 445                                         BlindedPath::one_hop_for_message(recipient, &*self.entropy_source, secp_ctx)
 446                                                 .map(|path| vec![path])
 447                                 } else {
 448                                         Err(())
 449                                 }
 450                         },
 451                 }
 452         }
 453 }
 454
 455 /// A path for sending an [`OnionMessage`].
 456 #[derive(Clone)]
 457 pub struct OnionMessagePath {
 458         /// Nodes on the path between the sender and the destination.
 459         pub intermediate_nodes: Vec<PublicKey>,
 460
 461         /// The recipient of the message.
 462         pub destination: Destination,
 463
 464         /// Addresses that may be used to connect to [`OnionMessagePath::first_node`].
 465         ///
 466         /// Only needs to be set if a connection to the node is required. [`OnionMessenger`] may use
 467         /// this to initiate such a connection.
 468         pub first_node_addresses: Option<Vec<SocketAddress>>,
 469 }
 470
 471 impl OnionMessagePath {
 472         /// Returns the first node in the path.
 473         pub fn first_node(&self) -> Option<PublicKey> {
 474                 self.intermediate_nodes
 475                         .first()
 476                         .copied()
 477                         .or_else(|| self.destination.first_node())
 478         }
 479 }
 480
 481 /// The destination of an onion message.
 482 #[derive(Clone, Hash, Debug, PartialEq, Eq)]
 483 pub enum Destination {
 484         /// We're sending this onion message to a node.
 485         Node(PublicKey),
 486         /// We're sending this onion message to a blinded path.
 487         BlindedPath(BlindedPath),
 488 }
 489
 490 impl Destination {
 491         /// Attempts to resolve the [`IntroductionNode::DirectedShortChannelId`] of a
 492         /// [`Destination::BlindedPath`] to a [`IntroductionNode::NodeId`], if applicable, using the
 493         /// provided [`ReadOnlyNetworkGraph`].
 494         pub fn resolve(&mut self, network_graph: &ReadOnlyNetworkGraph) {
 495                 if let Destination::BlindedPath(path) = self {
 496                         if let IntroductionNode::DirectedShortChannelId(..) = path.introduction_node {
 497                                 if let Some(pubkey) = path
 498                                         .public_introduction_node_id(network_graph)
 499                                         .and_then(|node_id| node_id.as_pubkey().ok())
 500                                 {
 501                                         path.introduction_node = IntroductionNode::NodeId(pubkey);
 502                                 }
 503                         }
 504                 }
 505         }
 506
 507         pub(super) fn num_hops(&self) -> usize {
 508                 match self {
 509                         Destination::Node(_) => 1,
 510                         Destination::BlindedPath(BlindedPath { blinded_hops, .. }) => blinded_hops.len(),
 511                 }
 512         }
 513
 514         fn first_node(&self) -> Option<PublicKey> {
 515                 match self {
 516                         Destination::Node(node_id) => Some(*node_id),
 517                         Destination::BlindedPath(BlindedPath { introduction_node, .. }) => {
 518                                 match introduction_node {
 519                                         IntroductionNode::NodeId(pubkey) => Some(*pubkey),
 520                                         IntroductionNode::DirectedShortChannelId(..) => None,
 521                                 }
 522                         },
 523                 }
 524         }
 525 }
 526
 527 /// Result of successfully [sending an onion message].
 528 ///
 529 /// [sending an onion message]: OnionMessenger::send_onion_message
 530 #[derive(Clone, Hash, Debug, PartialEq, Eq)]
 531 pub enum SendSuccess {
 532         /// The message was buffered and will be sent once it is processed by
 533         /// [`OnionMessageHandler::next_onion_message_for_peer`].
 534         Buffered,
 535         /// The message was buffered and will be sent once the node is connected as a peer and it is
 536         /// processed by [`OnionMessageHandler::next_onion_message_for_peer`].
 537         BufferedAwaitingConnection(PublicKey),
 538 }
 539
 540 /// Errors that may occur when [sending an onion message].
 541 ///
 542 /// [sending an onion message]: OnionMessenger::send_onion_message
 543 #[derive(Clone, Hash, Debug, PartialEq, Eq)]
 544 pub enum SendError {
 545         /// Errored computing onion message packet keys.
 546         Secp256k1(secp256k1::Error),
 547         /// Because implementations such as Eclair will drop onion messages where the message packet
 548         /// exceeds 32834 bytes, we refuse to send messages where the packet exceeds this size.
 549         TooBigPacket,
 550         /// The provided [`Destination`] was an invalid [`BlindedPath`] due to not having any blinded
 551         /// hops.
 552         TooFewBlindedHops,
 553         /// The first hop is not a peer and doesn't have a known [`SocketAddress`].
 554         InvalidFirstHop(PublicKey),
 555         /// A path from the sender to the destination could not be found by the [`MessageRouter`].
 556         PathNotFound,
 557         /// Onion message contents must have a TLV type >= 64.
 558         InvalidMessage,
 559         /// Our next-hop peer's buffer was full or our total outbound buffer was full.
 560         BufferFull,
 561         /// Failed to retrieve our node id from the provided [`NodeSigner`].
 562         ///
 563         /// [`NodeSigner`]: crate::sign::NodeSigner
 564         GetNodeIdFailed,
 565         /// The provided [`Destination`] has a blinded path with an unresolved introduction node. An
 566         /// attempt to resolve it in the [`MessageRouter`] when finding an [`OnionMessagePath`] likely
 567         /// failed.
 568         UnresolvedIntroductionNode,
 569         /// We attempted to send to a blinded path where we are the introduction node, and failed to
 570         /// advance the blinded path to make the second hop the new introduction node. Either
 571         /// [`NodeSigner::ecdh`] failed, we failed to tweak the current blinding point to get the
 572         /// new blinding point, or we were attempting to send to ourselves.
 573         BlindedPathAdvanceFailed,
 574 }
 575
 576 /// Handler for custom onion messages. If you are using [`SimpleArcOnionMessenger`],
 577 /// [`SimpleRefOnionMessenger`], or prefer to ignore inbound custom onion messages,
 578 /// [`IgnoringMessageHandler`] must be provided to [`OnionMessenger::new`]. Otherwise, a custom
 579 /// implementation of this trait must be provided, with [`CustomMessage`] specifying the supported
 580 /// message types.
 581 ///
 582 /// See [`OnionMessenger`] for example usage.
 583 ///
 584 /// [`IgnoringMessageHandler`]: crate::ln::peer_handler::IgnoringMessageHandler
 585 /// [`CustomMessage`]: Self::CustomMessage
 586 pub trait CustomOnionMessageHandler {
 587         /// The message known to the handler. To support multiple message types, you may want to make this
 588         /// an enum with a variant for each supported message.
 589         type CustomMessage: OnionMessageContents;
 590
 591         /// Called with the custom message that was received, returning a response to send, if any.
 592         ///
 593         /// The returned [`Self::CustomMessage`], if any, is enqueued to be sent by [`OnionMessenger`].
 594         fn handle_custom_message(&self, message: Self::CustomMessage, responder: Option<Responder>) -> ResponseInstruction<Self::CustomMessage>;
 595
 596         /// Read a custom message of type `message_type` from `buffer`, returning `Ok(None)` if the
 597         /// message type is unknown.
 598         fn read_custom_message<R: io::Read>(&self, message_type: u64, buffer: &mut R) -> Result<Option<Self::CustomMessage>, msgs::DecodeError>;
 599
 600         /// Releases any [`Self::CustomMessage`]s that need to be sent.
 601         ///
 602         /// Typically, this is used for messages initiating a message flow rather than in response to
 603         /// another message. The latter should use the return value of [`Self::handle_custom_message`].
 604         #[cfg(not(c_bindings))]
 605         fn release_pending_custom_messages(&self) -> Vec<PendingOnionMessage<Self::CustomMessage>>;
 606
 607         /// Releases any [`Self::CustomMessage`]s that need to be sent.
 608         ///
 609         /// Typically, this is used for messages initiating a message flow rather than in response to
 610         /// another message. The latter should use the return value of [`Self::handle_custom_message`].
 611         #[cfg(c_bindings)]
 612         fn release_pending_custom_messages(&self) -> Vec<(Self::CustomMessage, Destination, Option<BlindedPath>)>;
 613 }
 614
 615 /// A processed incoming onion message, containing either a Forward (another onion message)
 616 /// or a Receive payload with decrypted contents.
 617 #[derive(Clone, Debug)]
 618 pub enum PeeledOnion<T: OnionMessageContents> {
 619         /// Forwarded onion, with the next node id and a new onion
 620         Forward(NextMessageHop, OnionMessage),
 621         /// Received onion message, with decrypted contents, path_id, and reply path
 622         Receive(ParsedOnionMessageContents<T>, Option<[u8; 32]>, Option<BlindedPath>)
 623 }
 624
 625
 626 /// Creates an [`OnionMessage`] with the given `contents` for sending to the destination of
 627 /// `path`, first calling [`Destination::resolve`] on `path.destination` with the given
 628 /// [`ReadOnlyNetworkGraph`].
 629 ///
 630 /// Returns the node id of the peer to send the message to, the message itself, and any addresses
 631 /// needed to connect to the first node.
 632 pub fn create_onion_message_resolving_destination<
 633         ES: Deref, NS: Deref, NL: Deref, T: OnionMessageContents
 634 >(
 635         entropy_source: &ES, node_signer: &NS, node_id_lookup: &NL,
 636         network_graph: &ReadOnlyNetworkGraph, secp_ctx: &Secp256k1<secp256k1::All>,
 637         mut path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
 638 ) -> Result<(PublicKey, OnionMessage, Option<Vec<SocketAddress>>), SendError>
 639 where
 640         ES::Target: EntropySource,
 641         NS::Target: NodeSigner,
 642         NL::Target: NodeIdLookUp,
 643 {
 644         path.destination.resolve(network_graph);
 645         create_onion_message(
 646                 entropy_source, node_signer, node_id_lookup, secp_ctx, path, contents, reply_path,
 647         )
 648 }
 649
 650 /// Creates an [`OnionMessage`] with the given `contents` for sending to the destination of
 651 /// `path`.
 652 ///
 653 /// Returns the node id of the peer to send the message to, the message itself, and any addresses
 654 /// needed to connect to the first node.
 655 ///
 656 /// Returns [`SendError::UnresolvedIntroductionNode`] if:
 657 /// - `destination` contains a blinded path with an [`IntroductionNode::DirectedShortChannelId`],
 658 /// - unless it can be resolved by [`NodeIdLookUp::next_node_id`].
 659 /// Use [`create_onion_message_resolving_destination`] instead to resolve the introduction node
 660 /// first with a [`ReadOnlyNetworkGraph`].
 661 pub fn create_onion_message<ES: Deref, NS: Deref, NL: Deref, T: OnionMessageContents>(
 662         entropy_source: &ES, node_signer: &NS, node_id_lookup: &NL,
 663         secp_ctx: &Secp256k1<secp256k1::All>, path: OnionMessagePath, contents: T,
 664         reply_path: Option<BlindedPath>,
 665 ) -> Result<(PublicKey, OnionMessage, Option<Vec<SocketAddress>>), SendError>
 666 where
 667         ES::Target: EntropySource,
 668         NS::Target: NodeSigner,
 669         NL::Target: NodeIdLookUp,
 670 {
 671         let OnionMessagePath { intermediate_nodes, mut destination, first_node_addresses } = path;
 672         if let Destination::BlindedPath(BlindedPath { ref blinded_hops, .. }) = destination {
 673                 if blinded_hops.is_empty() {
 674                         return Err(SendError::TooFewBlindedHops);
 675                 }
 676         }
 677
 678         if contents.tlv_type() < 64 { return Err(SendError::InvalidMessage) }
 679
 680         // If we are sending straight to a blinded path and we are the introduction node, we need to
 681         // advance the blinded path by 1 hop so the second hop is the new introduction node.
 682         if intermediate_nodes.len() == 0 {
 683                 if let Destination::BlindedPath(ref mut blinded_path) = destination {
 684                         let our_node_id = node_signer.get_node_id(Recipient::Node)
 685                                 .map_err(|()| SendError::GetNodeIdFailed)?;
 686                         let introduction_node_id = match blinded_path.introduction_node {
 687                                 IntroductionNode::NodeId(pubkey) => pubkey,
 688                                 IntroductionNode::DirectedShortChannelId(direction, scid) => {
 689                                         match node_id_lookup.next_node_id(scid) {
 690                                                 Some(next_node_id) => *direction.select_pubkey(&our_node_id, &next_node_id),
 691                                                 None => return Err(SendError::UnresolvedIntroductionNode),
 692                                         }
 693                                 },
 694                         };
 695                         if introduction_node_id == our_node_id {
 696                                 advance_path_by_one(blinded_path, node_signer, node_id_lookup, &secp_ctx)
 697                                         .map_err(|()| SendError::BlindedPathAdvanceFailed)?;
 698                         }
 699                 }
 700         }
 701
 702         let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
 703         let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
 704         let (first_node_id, blinding_point) = if let Some(first_node_id) = intermediate_nodes.first() {
 705                 (*first_node_id, PublicKey::from_secret_key(&secp_ctx, &blinding_secret))
 706         } else {
 707                 match &destination {
 708                         Destination::Node(pk) => (*pk, PublicKey::from_secret_key(&secp_ctx, &blinding_secret)),
 709                         Destination::BlindedPath(BlindedPath { introduction_node, blinding_point, .. }) => {
 710                                 match introduction_node {
 711                                         IntroductionNode::NodeId(pubkey) => (*pubkey, *blinding_point),
 712                                         IntroductionNode::DirectedShortChannelId(..) => {
 713                                                 return Err(SendError::UnresolvedIntroductionNode);
 714                                         },
 715                                 }
 716                         }
 717                 }
 718         };
 719         let (packet_payloads, packet_keys) = packet_payloads_and_keys(
 720                 &secp_ctx, &intermediate_nodes, destination, contents, reply_path, &blinding_secret
 721         )?;
 722
 723         let prng_seed = entropy_source.get_secure_random_bytes();
 724         let onion_routing_packet = construct_onion_message_packet(
 725                 packet_payloads, packet_keys, prng_seed).map_err(|()| SendError::TooBigPacket)?;
 726
 727         let message = OnionMessage { blinding_point, onion_routing_packet };
 728         Ok((first_node_id, message, first_node_addresses))
 729 }
 730
 731 /// Decode one layer of an incoming [`OnionMessage`].
 732 ///
 733 /// Returns either the next layer of the onion for forwarding or the decrypted content for the
 734 /// receiver.
 735 pub fn peel_onion_message<NS: Deref, L: Deref, CMH: Deref>(
 736         msg: &OnionMessage, secp_ctx: &Secp256k1<secp256k1::All>, node_signer: NS, logger: L,
 737         custom_handler: CMH,
 738 ) -> Result<PeeledOnion<<<CMH>::Target as CustomOnionMessageHandler>::CustomMessage>, ()>
 739 where
 740         NS::Target: NodeSigner,
 741         L::Target: Logger,
 742         CMH::Target: CustomOnionMessageHandler,
 743 {
 744         let control_tlvs_ss = match node_signer.ecdh(Recipient::Node, &msg.blinding_point, None) {
 745                 Ok(ss) => ss,
 746                 Err(e) =>  {
 747                         log_error!(logger, "Failed to retrieve node secret: {:?}", e);
 748                         return Err(());
 749                 }
 750         };
 751         let onion_decode_ss = {
 752                 let blinding_factor = {
 753                         let mut hmac = HmacEngine::<Sha256>::new(b"blinded_node_id");
 754                         hmac.input(control_tlvs_ss.as_ref());
 755                         Hmac::from_engine(hmac).to_byte_array()
 756                 };
 757                 match node_signer.ecdh(Recipient::Node, &msg.onion_routing_packet.public_key,
 758                         Some(&Scalar::from_be_bytes(blinding_factor).unwrap()))
 759                 {
 760                         Ok(ss) => ss.secret_bytes(),
 761                         Err(()) => {
 762                                 log_trace!(logger, "Failed to compute onion packet shared secret");
 763                                 return Err(());
 764                         }
 765                 }
 766         };
 767         match onion_utils::decode_next_untagged_hop(
 768                 onion_decode_ss, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
 769                 (control_tlvs_ss, custom_handler.deref(), logger.deref())
 770         ) {
 771                 Ok((Payload::Receive::<ParsedOnionMessageContents<<<CMH as Deref>::Target as CustomOnionMessageHandler>::CustomMessage>> {
 772                         message, control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id }), reply_path,
 773                 }, None)) => {
 774                         Ok(PeeledOnion::Receive(message, path_id, reply_path))
 775                 },
 776                 Ok((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
 777                         next_hop, next_blinding_override
 778                 })), Some((next_hop_hmac, new_packet_bytes)))) => {
 779                         // TODO: we need to check whether `next_hop` is our node, in which case this is a dummy
 780                         // blinded hop and this onion message is destined for us. In this situation, we should keep
 781                         // unwrapping the onion layers to get to the final payload. Since we don't have the option
 782                         // of creating blinded paths with dummy hops currently, we should be ok to not handle this
 783                         // for now.
 784                         let new_pubkey = match onion_utils::next_hop_pubkey(&secp_ctx, msg.onion_routing_packet.public_key, &onion_decode_ss) {
 785                                 Ok(pk) => pk,
 786                                 Err(e) => {
 787                                         log_trace!(logger, "Failed to compute next hop packet pubkey: {}", e);
 788                                         return Err(())
 789                                 }
 790                         };
 791                         let outgoing_packet = Packet {
 792                                 version: 0,
 793                                 public_key: new_pubkey,
 794                                 hop_data: new_packet_bytes,
 795                                 hmac: next_hop_hmac,
 796                         };
 797                         let onion_message = OnionMessage {
 798                                 blinding_point: match next_blinding_override {
 799                                         Some(blinding_point) => blinding_point,
 800                                         None => {
 801                                                 match onion_utils::next_hop_pubkey(
 802                                                         &secp_ctx, msg.blinding_point, control_tlvs_ss.as_ref()
 803                                                 ) {
 804                                                         Ok(bp) => bp,
 805                                                         Err(e) => {
 806                                                                 log_trace!(logger, "Failed to compute next blinding point: {}", e);
 807                                                                 return Err(())
 808                                                         }
 809                                                 }
 810                                         }
 811                                 },
 812                                 onion_routing_packet: outgoing_packet,
 813                         };
 814
 815                         Ok(PeeledOnion::Forward(next_hop, onion_message))
 816                 },
 817                 Err(e) => {
 818                         log_trace!(logger, "Errored decoding onion message packet: {:?}", e);
 819                         Err(())
 820                 },
 821                 _ => {
 822                         log_trace!(logger, "Received bogus onion message packet, either the sender encoded a final hop as a forwarding hop or vice versa");
 823                         Err(())
 824                 },
 825         }
 826 }
 827
 828 impl<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, CMH: Deref>
 829 OnionMessenger<ES, NS, L, NL, MR, OMH, CMH>
 830 where
 831         ES::Target: EntropySource,
 832         NS::Target: NodeSigner,
 833         L::Target: Logger,
 834         NL::Target: NodeIdLookUp,
 835         MR::Target: MessageRouter,
 836         OMH::Target: OffersMessageHandler,
 837         CMH::Target: CustomOnionMessageHandler,
 838 {
 839         /// Constructs a new `OnionMessenger` to send, forward, and delegate received onion messages to
 840         /// their respective handlers.
 841         pub fn new(
 842                 entropy_source: ES, node_signer: NS, logger: L, node_id_lookup: NL, message_router: MR,
 843                 offers_handler: OMH, custom_handler: CMH
 844         ) -> Self {
 845                 let mut secp_ctx = Secp256k1::new();
 846                 secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
 847                 OnionMessenger {
 848                         entropy_source,
 849                         node_signer,
 850                         message_recipients: Mutex::new(new_hash_map()),
 851                         secp_ctx,
 852                         logger,
 853                         node_id_lookup,
 854                         message_router,
 855                         offers_handler,
 856                         custom_handler,
 857                 }
 858         }
 859
 860         #[cfg(test)]
 861         pub(crate) fn set_offers_handler(&mut self, offers_handler: OMH) {
 862                 self.offers_handler = offers_handler;
 863         }
 864
 865         /// Sends an [`OnionMessage`] with the given `contents` to `destination`.
 866         ///
 867         /// See [`OnionMessenger`] for example usage.
 868         pub fn send_onion_message<T: OnionMessageContents>(
 869                 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>
 870         ) -> Result<SendSuccess, SendError> {
 871                 self.find_path_and_enqueue_onion_message(
 872                         contents, destination, reply_path, format_args!("")
 873                 )
 874         }
 875
 876         fn find_path_and_enqueue_onion_message<T: OnionMessageContents>(
 877                 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>,
 878                 log_suffix: fmt::Arguments
 879         ) -> Result<SendSuccess, SendError> {
 880                 let mut logger = WithContext::from(&self.logger, None, None, None);
 881                 let result = self.find_path(destination).and_then(|path| {
 882                         let first_hop = path.intermediate_nodes.get(0).map(|p| *p);
 883                         logger = WithContext::from(&self.logger, first_hop, None, None);
 884                         self.enqueue_onion_message(path, contents, reply_path, log_suffix)
 885                 });
 886
 887                 match result.as_ref() {
 888                         Err(SendError::GetNodeIdFailed) => {
 889                                 log_warn!(logger, "Unable to retrieve node id {}", log_suffix);
 890                         },
 891                         Err(SendError::PathNotFound) => {
 892                                 log_trace!(logger, "Failed to find path {}", log_suffix);
 893                         },
 894                         Err(e) => {
 895                                 log_trace!(logger, "Failed sending onion message {}: {:?}", log_suffix, e);
 896                         },
 897                         Ok(SendSuccess::Buffered) => {
 898                                 log_trace!(logger, "Buffered onion message {}", log_suffix);
 899                         },
 900                         Ok(SendSuccess::BufferedAwaitingConnection(node_id)) => {
 901                                 log_trace!(
 902                                         logger,
 903                                         "Buffered onion message waiting on peer connection {}: {}",
 904                                         log_suffix, node_id
 905                                 );
 906                         },
 907                 }
 908
 909                 result
 910         }
 911
 912         fn find_path(&self, destination: Destination) -> Result<OnionMessagePath, SendError> {
 913                 let sender = self.node_signer
 914                         .get_node_id(Recipient::Node)
 915                         .map_err(|_| SendError::GetNodeIdFailed)?;
 916
 917                 let peers = self.message_recipients.lock().unwrap()
 918                         .iter()
 919                         .filter(|(_, recipient)| matches!(recipient, OnionMessageRecipient::ConnectedPeer(_)))
 920                         .map(|(node_id, _)| *node_id)
 921                         .collect();
 922
 923                 self.message_router
 924                         .find_path(sender, peers, destination)
 925                         .map_err(|_| SendError::PathNotFound)
 926         }
 927
 928         fn enqueue_onion_message<T: OnionMessageContents>(
 929                 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
 930                 log_suffix: fmt::Arguments
 931         ) -> Result<SendSuccess, SendError> {
 932                 log_trace!(self.logger, "Constructing onion message {}: {:?}", log_suffix, contents);
 933
 934                 let (first_node_id, onion_message, addresses) = create_onion_message(
 935                         &self.entropy_source, &self.node_signer, &self.node_id_lookup, &self.secp_ctx, path,
 936                         contents, reply_path,
 937                 )?;
 938
 939                 let mut message_recipients = self.message_recipients.lock().unwrap();
 940                 if outbound_buffer_full(&first_node_id, &message_recipients) {
 941                         return Err(SendError::BufferFull);
 942                 }
 943
 944                 match message_recipients.entry(first_node_id) {
 945                         hash_map::Entry::Vacant(e) => match addresses {
 946                                 None => Err(SendError::InvalidFirstHop(first_node_id)),
 947                                 Some(addresses) => {
 948                                         e.insert(OnionMessageRecipient::pending_connection(addresses))
 949                                                 .enqueue_message(onion_message);
 950                                         Ok(SendSuccess::BufferedAwaitingConnection(first_node_id))
 951                                 },
 952                         },
 953                         hash_map::Entry::Occupied(mut e) => {
 954                                 e.get_mut().enqueue_message(onion_message);
 955                                 if e.get().is_connected() {
 956                                         Ok(SendSuccess::Buffered)
 957                                 } else {
 958                                         Ok(SendSuccess::BufferedAwaitingConnection(first_node_id))
 959                                 }
 960                         },
 961                 }
 962         }
 963
 964         #[cfg(any(test, feature = "_test_utils"))]
 965         pub fn send_onion_message_using_path<T: OnionMessageContents>(
 966                 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>
 967         ) -> Result<SendSuccess, SendError> {
 968                 self.enqueue_onion_message(path, contents, reply_path, format_args!(""))
 969         }
 970
 971         pub(crate) fn peel_onion_message(
 972                 &self, msg: &OnionMessage
 973         ) -> Result<PeeledOnion<<<CMH>::Target as CustomOnionMessageHandler>::CustomMessage>, ()> {
 974                 peel_onion_message(
 975                         msg, &self.secp_ctx, &*self.node_signer, &*self.logger, &*self.custom_handler
 976                 )
 977         }
 978
 979         fn handle_onion_message_response<T: OnionMessageContents>(
 980                 &self, response: ResponseInstruction<T>
 981         ) {
 982                 if let ResponseInstruction::WithoutReplyPath(response) = response {
 983                         let message_type = response.message.msg_type();
 984                         let _ = self.find_path_and_enqueue_onion_message(
 985                                 response.message, Destination::BlindedPath(response.reply_path), None,
 986                                 format_args!(
 987                                         "when responding with {} to an onion message with path_id {:02x?}",
 988                                         message_type,
 989                                         response.path_id
 990                                 )
 991                         );
 992                 }
 993         }
 994
 995         #[cfg(test)]
 996         pub(super) fn release_pending_msgs(&self) -> HashMap<PublicKey, VecDeque<OnionMessage>> {
 997                 let mut message_recipients = self.message_recipients.lock().unwrap();
 998                 let mut msgs = new_hash_map();
 999                 // We don't want to disconnect the peers by removing them entirely from the original map, so we
1000                 // release the pending message buffers individually.
1001                 for (node_id, recipient) in &mut *message_recipients {
1002                         msgs.insert(*node_id, recipient.release_pending_messages());
1003                 }
1004                 msgs
1005         }
1006 }
1007
1008 fn outbound_buffer_full(peer_node_id: &PublicKey, buffer: &HashMap<PublicKey, OnionMessageRecipient>) -> bool {
1009         const MAX_TOTAL_BUFFER_SIZE: usize = (1 << 20) * 128;
1010         const MAX_PER_PEER_BUFFER_SIZE: usize = (1 << 10) * 256;
1011         let mut total_buffered_bytes = 0;
1012         let mut peer_buffered_bytes = 0;
1013         for (pk, peer_buf) in buffer {
1014                 for om in peer_buf.pending_messages() {
1015                         let om_len = om.serialized_length();
1016                         if pk == peer_node_id {
1017                                 peer_buffered_bytes += om_len;
1018                         }
1019                         total_buffered_bytes += om_len;
1020
1021                         if total_buffered_bytes >= MAX_TOTAL_BUFFER_SIZE ||
1022                                 peer_buffered_bytes >= MAX_PER_PEER_BUFFER_SIZE
1023                         {
1024                                 return true
1025                         }
1026                 }
1027         }
1028         false
1029 }
1030
1031 impl<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, CMH: Deref> EventsProvider
1032 for OnionMessenger<ES, NS, L, NL, MR, OMH, CMH>
1033 where
1034         ES::Target: EntropySource,
1035         NS::Target: NodeSigner,
1036         L::Target: Logger,
1037         NL::Target: NodeIdLookUp,
1038         MR::Target: MessageRouter,
1039         OMH::Target: OffersMessageHandler,
1040         CMH::Target: CustomOnionMessageHandler,
1041 {
1042         fn process_pending_events<H: Deref>(&self, handler: H) where H::Target: EventHandler {
1043                 for (node_id, recipient) in self.message_recipients.lock().unwrap().iter_mut() {
1044                         if let OnionMessageRecipient::PendingConnection(_, addresses, _) = recipient {
1045                                 if let Some(addresses) = addresses.take() {
1046                                         handler.handle_event(Event::ConnectionNeeded { node_id: *node_id, addresses });
1047                                 }
1048                         }
1049                 }
1050         }
1051 }
1052
1053 impl<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, CMH: Deref> OnionMessageHandler
1054 for OnionMessenger<ES, NS, L, NL, MR, OMH, CMH>
1055 where
1056         ES::Target: EntropySource,
1057         NS::Target: NodeSigner,
1058         L::Target: Logger,
1059         NL::Target: NodeIdLookUp,
1060         MR::Target: MessageRouter,
1061         OMH::Target: OffersMessageHandler,
1062         CMH::Target: CustomOnionMessageHandler,
1063 {
1064         fn handle_onion_message(&self, peer_node_id: &PublicKey, msg: &OnionMessage) {
1065                 let logger = WithContext::from(&self.logger, Some(*peer_node_id), None, None);
1066                 match self.peel_onion_message(msg) {
1067                         Ok(PeeledOnion::Receive(message, path_id, reply_path)) => {
1068                                 log_trace!(
1069                                         logger,
1070                                         "Received an onion message with path_id {:02x?} and {} reply_path: {:?}",
1071                                         path_id, if reply_path.is_some() { "a" } else { "no" }, message);
1072
1073                                 match message {
1074                                         ParsedOnionMessageContents::Offers(msg) => {
1075                                                 let responder = reply_path.map(
1076                                                         |reply_path| Responder::new(reply_path, path_id)
1077                                                 );
1078                                                 let response_instructions = self.offers_handler.handle_message(msg, responder);
1079                                                 self.handle_onion_message_response(response_instructions);
1080                                         },
1081                                         ParsedOnionMessageContents::Custom(msg) => {
1082                                                 let responder = reply_path.map(
1083                                                         |reply_path| Responder::new(reply_path, path_id)
1084                                                 );
1085                                                 let response_instructions = self.custom_handler.handle_custom_message(msg, responder);
1086                                                 self.handle_onion_message_response(response_instructions);
1087                                         },
1088                                 }
1089                         },
1090                         Ok(PeeledOnion::Forward(next_hop, onion_message)) => {
1091                                 let next_node_id = match next_hop {
1092                                         NextMessageHop::NodeId(pubkey) => pubkey,
1093                                         NextMessageHop::ShortChannelId(scid) => match self.node_id_lookup.next_node_id(scid) {
1094                                                 Some(pubkey) => pubkey,
1095                                                 None => {
1096                                                         log_trace!(self.logger, "Dropping forwarded onion messager: unable to resolve next hop using SCID {}", scid);
1097                                                         return
1098                                                 },
1099                                         },
1100                                 };
1101
1102                                 let mut message_recipients = self.message_recipients.lock().unwrap();
1103                                 if outbound_buffer_full(&next_node_id, &message_recipients) {
1104                                         log_trace!(
1105                                                 logger,
1106                                                 "Dropping forwarded onion message to peer {}: outbound buffer full",
1107                                                 next_node_id);
1108                                         return
1109                                 }
1110
1111                                 #[cfg(fuzzing)]
1112                                 message_recipients
1113                                         .entry(next_node_id)
1114                                         .or_insert_with(|| OnionMessageRecipient::ConnectedPeer(VecDeque::new()));
1115
1116                                 match message_recipients.entry(next_node_id) {
1117                                         hash_map::Entry::Occupied(mut e) if matches!(
1118                                                 e.get(), OnionMessageRecipient::ConnectedPeer(..)
1119                                         ) => {
1120                                                 e.get_mut().enqueue_message(onion_message);
1121                                                 log_trace!(logger, "Forwarding an onion message to peer {}", next_node_id);
1122                                         },
1123                                         _ => {
1124                                                 log_trace!(
1125                                                         logger,
1126                                                         "Dropping forwarded onion message to disconnected peer {}",
1127                                                         next_node_id);
1128                                                 return
1129                                         },
1130                                 }
1131                         },
1132                         Err(e) => {
1133                                 log_error!(logger, "Failed to process onion message {:?}", e);
1134                         }
1135                 }
1136         }
1137
1138         fn peer_connected(&self, their_node_id: &PublicKey, init: &msgs::Init, _inbound: bool) -> Result<(), ()> {
1139                 if init.features.supports_onion_messages() {
1140                         self.message_recipients.lock().unwrap()
1141                                 .entry(*their_node_id)
1142                                 .or_insert_with(|| OnionMessageRecipient::ConnectedPeer(VecDeque::new()))
1143                                 .mark_connected();
1144                 } else {
1145                         self.message_recipients.lock().unwrap().remove(their_node_id);
1146                 }
1147
1148                 Ok(())
1149         }
1150
1151         fn peer_disconnected(&self, their_node_id: &PublicKey) {
1152                 match self.message_recipients.lock().unwrap().remove(their_node_id) {
1153                         Some(OnionMessageRecipient::ConnectedPeer(..)) => {},
1154                         Some(_) => debug_assert!(false),
1155                         None => {},
1156                 }
1157         }
1158
1159         fn timer_tick_occurred(&self) {
1160                 let mut message_recipients = self.message_recipients.lock().unwrap();
1161
1162                 // Drop any pending recipients since the last call to avoid retaining buffered messages for
1163                 // too long.
1164                 message_recipients.retain(|_, recipient| match recipient {
1165                         OnionMessageRecipient::PendingConnection(_, None, ticks) => *ticks < MAX_TIMER_TICKS,
1166                         OnionMessageRecipient::PendingConnection(_, Some(_), _) => true,
1167                         _ => true,
1168                 });
1169
1170                 // Increment a timer tick for pending recipients so that their buffered messages are dropped
1171                 // at MAX_TIMER_TICKS.
1172                 for recipient in message_recipients.values_mut() {
1173                         if let OnionMessageRecipient::PendingConnection(_, None, ticks) = recipient {
1174                                 *ticks += 1;
1175                         }
1176                 }
1177         }
1178
1179         fn provided_node_features(&self) -> NodeFeatures {
1180                 let mut features = NodeFeatures::empty();
1181                 features.set_onion_messages_optional();
1182                 features
1183         }
1184
1185         fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
1186                 let mut features = InitFeatures::empty();
1187                 features.set_onion_messages_optional();
1188                 features
1189         }
1190
1191         // Before returning any messages to send for the peer, this method will see if any messages were
1192         // enqueued in the handler by users, find a path to the corresponding blinded path's introduction
1193         // node, and then enqueue the message for sending to the first peer in the full path.
1194         fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<OnionMessage> {
1195                 // Enqueue any initiating `OffersMessage`s to send.
1196                 for message in self.offers_handler.release_pending_messages() {
1197                         #[cfg(not(c_bindings))]
1198                         let PendingOnionMessage { contents, destination, reply_path } = message;
1199                         #[cfg(c_bindings)]
1200                         let (contents, destination, reply_path) = message;
1201                         let _ = self.find_path_and_enqueue_onion_message(
1202                                 contents, destination, reply_path, format_args!("when sending OffersMessage")
1203                         );
1204                 }
1205
1206                 // Enqueue any initiating `CustomMessage`s to send.
1207                 for message in self.custom_handler.release_pending_custom_messages() {
1208                         #[cfg(not(c_bindings))]
1209                         let PendingOnionMessage { contents, destination, reply_path } = message;
1210                         #[cfg(c_bindings)]
1211                         let (contents, destination, reply_path) = message;
1212                         let _ = self.find_path_and_enqueue_onion_message(
1213                                 contents, destination, reply_path, format_args!("when sending CustomMessage")
1214                         );
1215                 }
1216
1217                 self.message_recipients.lock().unwrap()
1218                         .get_mut(&peer_node_id)
1219                         .and_then(|buffer| buffer.dequeue_message())
1220         }
1221 }
1222
1223 // TODO: parameterize the below Simple* types with OnionMessenger and handle the messages it
1224 // produces
1225 /// Useful for simplifying the parameters of [`SimpleArcChannelManager`] and
1226 /// [`SimpleArcPeerManager`]. See their docs for more details.
1227 ///
1228 /// This is not exported to bindings users as type aliases aren't supported in most languages.
1229 ///
1230 /// [`SimpleArcChannelManager`]: crate::ln::channelmanager::SimpleArcChannelManager
1231 /// [`SimpleArcPeerManager`]: crate::ln::peer_handler::SimpleArcPeerManager
1232 #[cfg(not(c_bindings))]
1233 pub type SimpleArcOnionMessenger<M, T, F, L> = OnionMessenger<
1234         Arc<KeysManager>,
1235         Arc<KeysManager>,
1236         Arc<L>,
1237         Arc<SimpleArcChannelManager<M, T, F, L>>,
1238         Arc<DefaultMessageRouter<Arc<NetworkGraph<Arc<L>>>, Arc<L>, Arc<KeysManager>>>,
1239         Arc<SimpleArcChannelManager<M, T, F, L>>,
1240         IgnoringMessageHandler
1241 >;
1242
1243 /// Useful for simplifying the parameters of [`SimpleRefChannelManager`] and
1244 /// [`SimpleRefPeerManager`]. See their docs for more details.
1245 ///
1246 /// This is not exported to bindings users as type aliases aren't supported in most languages.
1247 ///
1248 /// [`SimpleRefChannelManager`]: crate::ln::channelmanager::SimpleRefChannelManager
1249 /// [`SimpleRefPeerManager`]: crate::ln::peer_handler::SimpleRefPeerManager
1250 #[cfg(not(c_bindings))]
1251 pub type SimpleRefOnionMessenger<
1252         'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, 'i, 'j, M, T, F, L
1253 > = OnionMessenger<
1254         &'a KeysManager,
1255         &'a KeysManager,
1256         &'b L,
1257         &'i SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, M, T, F, L>,
1258         &'j DefaultMessageRouter<&'g NetworkGraph<&'b L>, &'b L, &'a KeysManager>,
1259         &'i SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, M, T, F, L>,
1260         IgnoringMessageHandler
1261 >;
1262
1263 /// Construct onion packet payloads and keys for sending an onion message along the given
1264 /// `unblinded_path` to the given `destination`.
1265 fn packet_payloads_and_keys<T: OnionMessageContents, S: secp256k1::Signing + secp256k1::Verification>(
1266         secp_ctx: &Secp256k1<S>, unblinded_path: &[PublicKey], destination: Destination, message: T,
1267         mut reply_path: Option<BlindedPath>, session_priv: &SecretKey
1268 ) -> Result<(Vec<(Payload<T>, [u8; 32])>, Vec<onion_utils::OnionKeys>), SendError> {
1269         let num_hops = unblinded_path.len() + destination.num_hops();
1270         let mut payloads = Vec::with_capacity(num_hops);
1271         let mut onion_packet_keys = Vec::with_capacity(num_hops);
1272
1273         let (mut intro_node_id_blinding_pt, num_blinded_hops) = match &destination {
1274                 Destination::Node(_) => (None, 0),
1275                 Destination::BlindedPath(BlindedPath { introduction_node, blinding_point, blinded_hops }) => {
1276                         let introduction_node_id = match introduction_node {
1277                                 IntroductionNode::NodeId(pubkey) => pubkey,
1278                                 IntroductionNode::DirectedShortChannelId(..) => {
1279                                         return Err(SendError::UnresolvedIntroductionNode);
1280                                 },
1281                         };
1282                         (Some((*introduction_node_id, *blinding_point)), blinded_hops.len())
1283                 },
1284         };
1285         let num_unblinded_hops = num_hops - num_blinded_hops;
1286
1287         let mut unblinded_path_idx = 0;
1288         let mut blinded_path_idx = 0;
1289         let mut prev_control_tlvs_ss = None;
1290         let mut final_control_tlvs = None;
1291         utils::construct_keys_callback(secp_ctx, unblinded_path.iter(), Some(destination), session_priv,
1292                 |_, onion_packet_ss, ephemeral_pubkey, control_tlvs_ss, unblinded_pk_opt, enc_payload_opt| {
1293                         if num_unblinded_hops != 0 && unblinded_path_idx < num_unblinded_hops {
1294                                 if let Some(ss) = prev_control_tlvs_ss.take() {
1295                                         payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(
1296                                                 ForwardTlvs {
1297                                                         next_hop: NextMessageHop::NodeId(unblinded_pk_opt.unwrap()),
1298                                                         next_blinding_override: None,
1299                                                 }
1300                                         )), ss));
1301                                 }
1302                                 prev_control_tlvs_ss = Some(control_tlvs_ss);
1303                                 unblinded_path_idx += 1;
1304                         } else if let Some((intro_node_id, blinding_pt)) = intro_node_id_blinding_pt.take() {
1305                                 if let Some(control_tlvs_ss) = prev_control_tlvs_ss.take() {
1306                                         payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
1307                                                 next_hop: NextMessageHop::NodeId(intro_node_id),
1308                                                 next_blinding_override: Some(blinding_pt),
1309                                         })), control_tlvs_ss));
1310                                 }
1311                         }
1312                         if blinded_path_idx < num_blinded_hops.saturating_sub(1) && enc_payload_opt.is_some() {
1313                                 payloads.push((Payload::Forward(ForwardControlTlvs::Blinded(enc_payload_opt.unwrap())),
1314                                         control_tlvs_ss));
1315                                 blinded_path_idx += 1;
1316                         } else if let Some(encrypted_payload) = enc_payload_opt {
1317                                 final_control_tlvs = Some(ReceiveControlTlvs::Blinded(encrypted_payload));
1318                                 prev_control_tlvs_ss = Some(control_tlvs_ss);
1319                         }
1320
1321                         let (rho, mu) = onion_utils::gen_rho_mu_from_shared_secret(onion_packet_ss.as_ref());
1322                         onion_packet_keys.push(onion_utils::OnionKeys {
1323                                 #[cfg(test)]
1324                                 shared_secret: onion_packet_ss,
1325                                 #[cfg(test)]
1326                                 blinding_factor: [0; 32],
1327                                 ephemeral_pubkey,
1328                                 rho,
1329                                 mu,
1330                         });
1331                 }
1332         ).map_err(|e| SendError::Secp256k1(e))?;
1333
1334         if let Some(control_tlvs) = final_control_tlvs {
1335                 payloads.push((Payload::Receive {
1336                         control_tlvs,
1337                         reply_path: reply_path.take(),
1338                         message,
1339                 }, prev_control_tlvs_ss.unwrap()));
1340         } else {
1341                 payloads.push((Payload::Receive {
1342                         control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id: None, }),
1343                         reply_path: reply_path.take(),
1344                         message,
1345                 }, prev_control_tlvs_ss.unwrap()));
1346         }
1347
1348         Ok((payloads, onion_packet_keys))
1349 }
1350
1351 /// Errors if the serialized payload size exceeds onion_message::BIG_PACKET_HOP_DATA_LEN
1352 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, ()> {
1353         // Spec rationale:
1354         // "`len` allows larger messages to be sent than the standard 1300 bytes allowed for an HTLC
1355         // onion, but this should be used sparingly as it is reduces anonymity set, hence the
1356         // recommendation that it either look like an HTLC onion, or if larger, be a fixed size."
1357         let payloads_ser_len = onion_utils::payloads_serialized_length(&payloads);
1358         let hop_data_len = if payloads_ser_len <= SMALL_PACKET_HOP_DATA_LEN {
1359                 SMALL_PACKET_HOP_DATA_LEN
1360         } else if payloads_ser_len <= BIG_PACKET_HOP_DATA_LEN {
1361                 BIG_PACKET_HOP_DATA_LEN
1362         } else { return Err(()) };
1363
1364         onion_utils::construct_onion_message_packet::<_, _>(
1365                 payloads, onion_keys, prng_seed, hop_data_len)
1366 }