1 // This file is Copyright its original authors, visible in version control
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
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.
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};
18 use crate::blinded_path::{BlindedPath, IntroductionNode, NextMessageHop, NodeIdLookUp};
19 use crate::blinded_path::message::{advance_path_by_one, ForwardNode, 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;
37 use crate::sync::Mutex;
38 use crate::prelude::*;
40 #[cfg(not(c_bindings))]
42 crate::sign::KeysManager,
43 crate::ln::channelmanager::{SimpleArcChannelManager, SimpleRefChannelManager},
44 crate::ln::peer_handler::IgnoringMessageHandler,
48 pub(super) const MAX_TIMER_TICKS: usize = 2;
50 /// A sender, receiver and forwarder of [`OnionMessage`]s.
52 /// # Handling Messages
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
60 /// # Sending Messages
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
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::blinded_path::message::ForwardNode;
75 /// # use lightning::sign::{EntropySource, KeysManager};
76 /// # use lightning::ln::peer_handler::IgnoringMessageHandler;
77 /// # use lightning::onion_message::messenger::{Destination, MessageRouter, OnionMessagePath, OnionMessenger};
78 /// # use lightning::onion_message::packet::OnionMessageContents;
79 /// # use lightning::util::logger::{Logger, Record};
80 /// # use lightning::util::ser::{Writeable, Writer};
81 /// # use lightning::io;
82 /// # use std::sync::Arc;
83 /// # struct FakeLogger;
84 /// # impl Logger for FakeLogger {
85 /// # fn log(&self, record: Record) { println!("{:?}" , record); }
87 /// # struct FakeMessageRouter {}
88 /// # impl MessageRouter for FakeMessageRouter {
89 /// # fn find_path(&self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination) -> Result<OnionMessagePath, ()> {
90 /// # let secp_ctx = Secp256k1::new();
91 /// # let node_secret = SecretKey::from_slice(&<Vec<u8>>::from_hex("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
92 /// # let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
93 /// # let hop_node_id2 = hop_node_id1;
94 /// # Ok(OnionMessagePath {
95 /// # intermediate_nodes: vec![hop_node_id1, hop_node_id2],
97 /// # first_node_addresses: None,
100 /// # fn create_blinded_paths<T: secp256k1::Signing + secp256k1::Verification>(
101 /// # &self, _recipient: PublicKey, _peers: Vec<ForwardNode>, _secp_ctx: &Secp256k1<T>
102 /// # ) -> Result<Vec<BlindedPath>, ()> {
106 /// # let seed = [42u8; 32];
107 /// # let time = Duration::from_secs(123456);
108 /// # let keys_manager = KeysManager::new(&seed, time.as_secs(), time.subsec_nanos());
109 /// # let logger = Arc::new(FakeLogger {});
110 /// # let node_secret = SecretKey::from_slice(&<Vec<u8>>::from_hex("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
111 /// # let secp_ctx = Secp256k1::new();
112 /// # let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
113 /// # let (hop_node_id3, hop_node_id4) = (hop_node_id1, hop_node_id1);
114 /// # let destination_node_id = hop_node_id1;
115 /// # let node_id_lookup = EmptyNodeIdLookUp {};
116 /// # let message_router = Arc::new(FakeMessageRouter {});
117 /// # let custom_message_handler = IgnoringMessageHandler {};
118 /// # let offers_message_handler = IgnoringMessageHandler {};
119 /// // Create the onion messenger. This must use the same `keys_manager` as is passed to your
120 /// // ChannelManager.
121 /// let onion_messenger = OnionMessenger::new(
122 /// &keys_manager, &keys_manager, logger, &node_id_lookup, message_router,
123 /// &offers_message_handler, &custom_message_handler
126 /// # #[derive(Debug)]
127 /// # struct YourCustomMessage {}
128 /// impl Writeable for YourCustomMessage {
129 /// fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
131 /// // Write your custom onion message to `w`
134 /// impl OnionMessageContents for YourCustomMessage {
135 /// fn tlv_type(&self) -> u64 {
136 /// # let your_custom_message_type = 42;
137 /// your_custom_message_type
139 /// fn msg_type(&self) -> &'static str { "YourCustomMessageType" }
141 /// // Send a custom onion message to a node id.
142 /// let destination = Destination::Node(destination_node_id);
143 /// let reply_path = None;
144 /// # let message = YourCustomMessage {};
145 /// onion_messenger.send_onion_message(message, destination, reply_path);
147 /// // Create a blinded path to yourself, for someone to send an onion message to.
148 /// # let your_node_id = hop_node_id1;
150 /// ForwardNode { node_id: hop_node_id3, short_channel_id: None },
151 /// ForwardNode { node_id: hop_node_id4, short_channel_id: None },
153 /// let blinded_path = BlindedPath::new_for_message(&hops, your_node_id, &keys_manager, &secp_ctx).unwrap();
155 /// // Send a custom onion message to a blinded path.
156 /// let destination = Destination::BlindedPath(blinded_path);
157 /// let reply_path = None;
158 /// # let message = YourCustomMessage {};
159 /// onion_messenger.send_onion_message(message, destination, reply_path);
162 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
163 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
164 pub struct OnionMessenger<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, CMH: Deref>
166 ES::Target: EntropySource,
167 NS::Target: NodeSigner,
169 NL::Target: NodeIdLookUp,
170 MR::Target: MessageRouter,
171 OMH::Target: OffersMessageHandler,
172 CMH::Target: CustomOnionMessageHandler,
177 message_recipients: Mutex<HashMap<PublicKey, OnionMessageRecipient>>,
178 secp_ctx: Secp256k1<secp256k1::All>,
183 intercept_messages_for_offline_peers: bool,
184 pending_events: Mutex<Vec<Event>>,
187 /// [`OnionMessage`]s buffered to be sent.
188 enum OnionMessageRecipient {
189 /// Messages for a node connected as a peer.
190 ConnectedPeer(VecDeque<OnionMessage>),
192 /// Messages for a node that is not yet connected, which are dropped after [`MAX_TIMER_TICKS`]
193 /// and tracked here.
194 PendingConnection(VecDeque<OnionMessage>, Option<Vec<SocketAddress>>, usize),
197 impl OnionMessageRecipient {
198 fn pending_connection(addresses: Vec<SocketAddress>) -> Self {
199 Self::PendingConnection(VecDeque::new(), Some(addresses), 0)
202 fn pending_messages(&self) -> &VecDeque<OnionMessage> {
204 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
205 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
209 fn enqueue_message(&mut self, message: OnionMessage) {
210 let pending_messages = match self {
211 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
212 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
215 pending_messages.push_back(message);
218 fn dequeue_message(&mut self) -> Option<OnionMessage> {
219 let pending_messages = match self {
220 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
221 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => {
222 debug_assert!(false);
227 pending_messages.pop_front()
231 fn release_pending_messages(&mut self) -> VecDeque<OnionMessage> {
232 let pending_messages = match self {
233 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
234 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
237 core::mem::take(pending_messages)
240 fn mark_connected(&mut self) {
241 if let OnionMessageRecipient::PendingConnection(pending_messages, _, _) = self {
242 let mut new_pending_messages = VecDeque::new();
243 core::mem::swap(pending_messages, &mut new_pending_messages);
244 *self = OnionMessageRecipient::ConnectedPeer(new_pending_messages);
248 fn is_connected(&self) -> bool {
250 OnionMessageRecipient::ConnectedPeer(..) => true,
251 OnionMessageRecipient::PendingConnection(..) => false,
257 /// The `Responder` struct creates an appropriate [`ResponseInstruction`]
258 /// for responding to a message.
259 pub struct Responder {
260 /// The path along which a response can be sent.
261 reply_path: BlindedPath,
262 path_id: Option<[u8; 32]>
266 /// Creates a new [`Responder`] instance with the provided reply path.
267 fn new(reply_path: BlindedPath, path_id: Option<[u8; 32]>) -> Self {
274 /// Creates the appropriate [`ResponseInstruction`] for a given response.
275 pub fn respond<T: OnionMessageContents>(self, response: T) -> ResponseInstruction<T> {
276 ResponseInstruction::WithoutReplyPath(OnionMessageResponse {
278 reply_path: self.reply_path,
279 path_id: self.path_id,
284 /// This struct contains the information needed to reply to a received message.
285 pub struct OnionMessageResponse<T: OnionMessageContents> {
287 reply_path: BlindedPath,
288 path_id: Option<[u8; 32]>,
291 /// `ResponseInstruction` represents instructions for responding to received messages.
292 pub enum ResponseInstruction<T: OnionMessageContents> {
293 /// Indicates that a response should be sent without including a reply path
294 /// for the recipient to respond back.
295 WithoutReplyPath(OnionMessageResponse<T>),
296 /// Indicates that there's no response to send back.
300 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
302 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
303 /// enqueued for sending.
304 #[cfg(not(c_bindings))]
305 pub struct PendingOnionMessage<T: OnionMessageContents> {
306 /// The message contents to send in an [`OnionMessage`].
309 /// The destination of the message.
310 pub destination: Destination,
312 /// A reply path to include in the [`OnionMessage`] for a response.
313 pub reply_path: Option<BlindedPath>,
317 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
319 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
320 /// enqueued for sending.
321 pub type PendingOnionMessage<T> = (T, Destination, Option<BlindedPath>);
323 pub(crate) fn new_pending_onion_message<T: OnionMessageContents>(
324 contents: T, destination: Destination, reply_path: Option<BlindedPath>
325 ) -> PendingOnionMessage<T> {
326 #[cfg(not(c_bindings))]
327 return PendingOnionMessage { contents, destination, reply_path };
329 return (contents, destination, reply_path);
332 /// A trait defining behavior for routing an [`OnionMessage`].
333 pub trait MessageRouter {
334 /// Returns a route for sending an [`OnionMessage`] to the given [`Destination`].
336 &self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
337 ) -> Result<OnionMessagePath, ()>;
339 /// Creates [`BlindedPath`]s to the `recipient` node. The nodes in `peers` are assumed to be
340 /// direct peers with the `recipient`.
341 fn create_blinded_paths<
342 T: secp256k1::Signing + secp256k1::Verification
344 &self, recipient: PublicKey, peers: Vec<ForwardNode>, secp_ctx: &Secp256k1<T>,
345 ) -> Result<Vec<BlindedPath>, ()>;
348 /// A [`MessageRouter`] that can only route to a directly connected [`Destination`].
349 pub struct DefaultMessageRouter<G: Deref<Target=NetworkGraph<L>>, L: Deref, ES: Deref>
352 ES::Target: EntropySource,
358 impl<G: Deref<Target=NetworkGraph<L>>, L: Deref, ES: Deref> DefaultMessageRouter<G, L, ES>
361 ES::Target: EntropySource,
363 /// Creates a [`DefaultMessageRouter`] using the given [`NetworkGraph`].
364 pub fn new(network_graph: G, entropy_source: ES) -> Self {
365 Self { network_graph, entropy_source }
369 impl<G: Deref<Target=NetworkGraph<L>>, L: Deref, ES: Deref> MessageRouter for DefaultMessageRouter<G, L, ES>
372 ES::Target: EntropySource,
375 &self, sender: PublicKey, peers: Vec<PublicKey>, mut destination: Destination
376 ) -> Result<OnionMessagePath, ()> {
377 let network_graph = self.network_graph.deref().read_only();
378 destination.resolve(&network_graph);
380 let first_node = match destination.first_node() {
381 Some(first_node) => first_node,
382 None => return Err(()),
385 if peers.contains(&first_node) || sender == first_node {
386 Ok(OnionMessagePath {
387 intermediate_nodes: vec![], destination, first_node_addresses: None
390 let node_announcement = network_graph
391 .node(&NodeId::from_pubkey(&first_node))
392 .and_then(|node_info| node_info.announcement_info.as_ref())
393 .and_then(|announcement_info| announcement_info.announcement_message.as_ref())
394 .map(|node_announcement| &node_announcement.contents);
396 match node_announcement {
397 Some(node_announcement) if node_announcement.features.supports_onion_messages() => {
398 let first_node_addresses = Some(node_announcement.addresses.clone());
399 Ok(OnionMessagePath {
400 intermediate_nodes: vec![], destination, first_node_addresses
408 fn create_blinded_paths<
409 T: secp256k1::Signing + secp256k1::Verification
411 &self, recipient: PublicKey, peers: Vec<ForwardNode>, secp_ctx: &Secp256k1<T>,
412 ) -> Result<Vec<BlindedPath>, ()> {
413 // Limit the number of blinded paths that are computed.
414 const MAX_PATHS: usize = 3;
416 // Ensure peers have at least three channels so that it is more difficult to infer the
417 // recipient's node_id.
418 const MIN_PEER_CHANNELS: usize = 3;
420 let network_graph = self.network_graph.deref().read_only();
421 let is_recipient_announced =
422 network_graph.nodes().contains_key(&NodeId::from_pubkey(&recipient));
424 let mut peer_info = peers.into_iter()
425 // Limit to peers with announced channels
428 .node(&NodeId::from_pubkey(&peer.node_id))
429 .filter(|info| info.channels.len() >= MIN_PEER_CHANNELS)
430 .map(|info| (peer, info.is_tor_only(), info.channels.len()))
432 // Exclude Tor-only nodes when the recipient is announced.
433 .filter(|(_, is_tor_only, _)| !(*is_tor_only && is_recipient_announced))
434 .collect::<Vec<_>>();
436 // Prefer using non-Tor nodes with the most channels as the introduction node.
437 peer_info.sort_unstable_by(|(_, a_tor_only, a_channels), (_, b_tor_only, b_channels)| {
438 a_tor_only.cmp(b_tor_only).then(a_channels.cmp(b_channels).reverse())
441 let paths = peer_info.into_iter()
442 .map(|(peer, _, _)| {
443 BlindedPath::new_for_message(&[peer], recipient, &*self.entropy_source, secp_ctx)
446 .collect::<Result<Vec<_>, _>>();
448 let mut paths = match paths {
449 Ok(paths) if !paths.is_empty() => Ok(paths),
451 if is_recipient_announced {
452 BlindedPath::one_hop_for_message(recipient, &*self.entropy_source, secp_ctx)
453 .map(|path| vec![path])
459 for path in &mut paths {
460 path.use_compact_introduction_node(&network_graph);
467 /// A path for sending an [`OnionMessage`].
469 pub struct OnionMessagePath {
470 /// Nodes on the path between the sender and the destination.
471 pub intermediate_nodes: Vec<PublicKey>,
473 /// The recipient of the message.
474 pub destination: Destination,
476 /// Addresses that may be used to connect to [`OnionMessagePath::first_node`].
478 /// Only needs to be set if a connection to the node is required. [`OnionMessenger`] may use
479 /// this to initiate such a connection.
480 pub first_node_addresses: Option<Vec<SocketAddress>>,
483 impl OnionMessagePath {
484 /// Returns the first node in the path.
485 pub fn first_node(&self) -> Option<PublicKey> {
486 self.intermediate_nodes
489 .or_else(|| self.destination.first_node())
493 /// The destination of an onion message.
494 #[derive(Clone, Hash, Debug, PartialEq, Eq)]
495 pub enum Destination {
496 /// We're sending this onion message to a node.
498 /// We're sending this onion message to a blinded path.
499 BlindedPath(BlindedPath),
503 /// Attempts to resolve the [`IntroductionNode::DirectedShortChannelId`] of a
504 /// [`Destination::BlindedPath`] to a [`IntroductionNode::NodeId`], if applicable, using the
505 /// provided [`ReadOnlyNetworkGraph`].
506 pub fn resolve(&mut self, network_graph: &ReadOnlyNetworkGraph) {
507 if let Destination::BlindedPath(path) = self {
508 if let IntroductionNode::DirectedShortChannelId(..) = path.introduction_node {
509 if let Some(pubkey) = path
510 .public_introduction_node_id(network_graph)
511 .and_then(|node_id| node_id.as_pubkey().ok())
513 path.introduction_node = IntroductionNode::NodeId(pubkey);
519 pub(super) fn num_hops(&self) -> usize {
521 Destination::Node(_) => 1,
522 Destination::BlindedPath(BlindedPath { blinded_hops, .. }) => blinded_hops.len(),
526 fn first_node(&self) -> Option<PublicKey> {
528 Destination::Node(node_id) => Some(*node_id),
529 Destination::BlindedPath(BlindedPath { introduction_node, .. }) => {
530 match introduction_node {
531 IntroductionNode::NodeId(pubkey) => Some(*pubkey),
532 IntroductionNode::DirectedShortChannelId(..) => None,
539 /// Result of successfully [sending an onion message].
541 /// [sending an onion message]: OnionMessenger::send_onion_message
542 #[derive(Clone, Hash, Debug, PartialEq, Eq)]
543 pub enum SendSuccess {
544 /// The message was buffered and will be sent once it is processed by
545 /// [`OnionMessageHandler::next_onion_message_for_peer`].
547 /// The message was buffered and will be sent once the node is connected as a peer and it is
548 /// processed by [`OnionMessageHandler::next_onion_message_for_peer`].
549 BufferedAwaitingConnection(PublicKey),
552 /// Errors that may occur when [sending an onion message].
554 /// [sending an onion message]: OnionMessenger::send_onion_message
555 #[derive(Clone, Hash, Debug, PartialEq, Eq)]
557 /// Errored computing onion message packet keys.
558 Secp256k1(secp256k1::Error),
559 /// Because implementations such as Eclair will drop onion messages where the message packet
560 /// exceeds 32834 bytes, we refuse to send messages where the packet exceeds this size.
562 /// The provided [`Destination`] was an invalid [`BlindedPath`] due to not having any blinded
565 /// The first hop is not a peer and doesn't have a known [`SocketAddress`].
566 InvalidFirstHop(PublicKey),
567 /// A path from the sender to the destination could not be found by the [`MessageRouter`].
569 /// Onion message contents must have a TLV type >= 64.
571 /// Our next-hop peer's buffer was full or our total outbound buffer was full.
573 /// Failed to retrieve our node id from the provided [`NodeSigner`].
575 /// [`NodeSigner`]: crate::sign::NodeSigner
577 /// The provided [`Destination`] has a blinded path with an unresolved introduction node. An
578 /// attempt to resolve it in the [`MessageRouter`] when finding an [`OnionMessagePath`] likely
580 UnresolvedIntroductionNode,
581 /// We attempted to send to a blinded path where we are the introduction node, and failed to
582 /// advance the blinded path to make the second hop the new introduction node. Either
583 /// [`NodeSigner::ecdh`] failed, we failed to tweak the current blinding point to get the
584 /// new blinding point, or we were attempting to send to ourselves.
585 BlindedPathAdvanceFailed,
588 /// Handler for custom onion messages. If you are using [`SimpleArcOnionMessenger`],
589 /// [`SimpleRefOnionMessenger`], or prefer to ignore inbound custom onion messages,
590 /// [`IgnoringMessageHandler`] must be provided to [`OnionMessenger::new`]. Otherwise, a custom
591 /// implementation of this trait must be provided, with [`CustomMessage`] specifying the supported
594 /// See [`OnionMessenger`] for example usage.
596 /// [`IgnoringMessageHandler`]: crate::ln::peer_handler::IgnoringMessageHandler
597 /// [`CustomMessage`]: Self::CustomMessage
598 pub trait CustomOnionMessageHandler {
599 /// The message known to the handler. To support multiple message types, you may want to make this
600 /// an enum with a variant for each supported message.
601 type CustomMessage: OnionMessageContents;
603 /// Called with the custom message that was received, returning a response to send, if any.
605 /// The returned [`Self::CustomMessage`], if any, is enqueued to be sent by [`OnionMessenger`].
606 fn handle_custom_message(&self, message: Self::CustomMessage, responder: Option<Responder>) -> ResponseInstruction<Self::CustomMessage>;
608 /// Read a custom message of type `message_type` from `buffer`, returning `Ok(None)` if the
609 /// message type is unknown.
610 fn read_custom_message<R: io::Read>(&self, message_type: u64, buffer: &mut R) -> Result<Option<Self::CustomMessage>, msgs::DecodeError>;
612 /// Releases any [`Self::CustomMessage`]s that need to be sent.
614 /// Typically, this is used for messages initiating a message flow rather than in response to
615 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
616 #[cfg(not(c_bindings))]
617 fn release_pending_custom_messages(&self) -> Vec<PendingOnionMessage<Self::CustomMessage>>;
619 /// Releases any [`Self::CustomMessage`]s that need to be sent.
621 /// Typically, this is used for messages initiating a message flow rather than in response to
622 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
624 fn release_pending_custom_messages(&self) -> Vec<(Self::CustomMessage, Destination, Option<BlindedPath>)>;
627 /// A processed incoming onion message, containing either a Forward (another onion message)
628 /// or a Receive payload with decrypted contents.
629 #[derive(Clone, Debug)]
630 pub enum PeeledOnion<T: OnionMessageContents> {
631 /// Forwarded onion, with the next node id and a new onion
632 Forward(NextMessageHop, OnionMessage),
633 /// Received onion message, with decrypted contents, path_id, and reply path
634 Receive(ParsedOnionMessageContents<T>, Option<[u8; 32]>, Option<BlindedPath>)
638 /// Creates an [`OnionMessage`] with the given `contents` for sending to the destination of
639 /// `path`, first calling [`Destination::resolve`] on `path.destination` with the given
640 /// [`ReadOnlyNetworkGraph`].
642 /// Returns the node id of the peer to send the message to, the message itself, and any addresses
643 /// needed to connect to the first node.
644 pub fn create_onion_message_resolving_destination<
645 ES: Deref, NS: Deref, NL: Deref, T: OnionMessageContents
647 entropy_source: &ES, node_signer: &NS, node_id_lookup: &NL,
648 network_graph: &ReadOnlyNetworkGraph, secp_ctx: &Secp256k1<secp256k1::All>,
649 mut path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
650 ) -> Result<(PublicKey, OnionMessage, Option<Vec<SocketAddress>>), SendError>
652 ES::Target: EntropySource,
653 NS::Target: NodeSigner,
654 NL::Target: NodeIdLookUp,
656 path.destination.resolve(network_graph);
657 create_onion_message(
658 entropy_source, node_signer, node_id_lookup, secp_ctx, path, contents, reply_path,
662 /// Creates an [`OnionMessage`] with the given `contents` for sending to the destination of
665 /// Returns the node id of the peer to send the message to, the message itself, and any addresses
666 /// needed to connect to the first node.
668 /// Returns [`SendError::UnresolvedIntroductionNode`] if:
669 /// - `destination` contains a blinded path with an [`IntroductionNode::DirectedShortChannelId`],
670 /// - unless it can be resolved by [`NodeIdLookUp::next_node_id`].
671 /// Use [`create_onion_message_resolving_destination`] instead to resolve the introduction node
672 /// first with a [`ReadOnlyNetworkGraph`].
673 pub fn create_onion_message<ES: Deref, NS: Deref, NL: Deref, T: OnionMessageContents>(
674 entropy_source: &ES, node_signer: &NS, node_id_lookup: &NL,
675 secp_ctx: &Secp256k1<secp256k1::All>, path: OnionMessagePath, contents: T,
676 reply_path: Option<BlindedPath>,
677 ) -> Result<(PublicKey, OnionMessage, Option<Vec<SocketAddress>>), SendError>
679 ES::Target: EntropySource,
680 NS::Target: NodeSigner,
681 NL::Target: NodeIdLookUp,
683 let OnionMessagePath { intermediate_nodes, mut destination, first_node_addresses } = path;
684 if let Destination::BlindedPath(BlindedPath { ref blinded_hops, .. }) = destination {
685 if blinded_hops.is_empty() {
686 return Err(SendError::TooFewBlindedHops);
690 if contents.tlv_type() < 64 { return Err(SendError::InvalidMessage) }
692 // If we are sending straight to a blinded path and we are the introduction node, we need to
693 // advance the blinded path by 1 hop so the second hop is the new introduction node.
694 if intermediate_nodes.len() == 0 {
695 if let Destination::BlindedPath(ref mut blinded_path) = destination {
696 let our_node_id = node_signer.get_node_id(Recipient::Node)
697 .map_err(|()| SendError::GetNodeIdFailed)?;
698 let introduction_node_id = match blinded_path.introduction_node {
699 IntroductionNode::NodeId(pubkey) => pubkey,
700 IntroductionNode::DirectedShortChannelId(direction, scid) => {
701 match node_id_lookup.next_node_id(scid) {
702 Some(next_node_id) => *direction.select_pubkey(&our_node_id, &next_node_id),
703 None => return Err(SendError::UnresolvedIntroductionNode),
707 if introduction_node_id == our_node_id {
708 advance_path_by_one(blinded_path, node_signer, node_id_lookup, &secp_ctx)
709 .map_err(|()| SendError::BlindedPathAdvanceFailed)?;
714 let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
715 let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
716 let (first_node_id, blinding_point) = if let Some(first_node_id) = intermediate_nodes.first() {
717 (*first_node_id, PublicKey::from_secret_key(&secp_ctx, &blinding_secret))
720 Destination::Node(pk) => (*pk, PublicKey::from_secret_key(&secp_ctx, &blinding_secret)),
721 Destination::BlindedPath(BlindedPath { introduction_node, blinding_point, .. }) => {
722 match introduction_node {
723 IntroductionNode::NodeId(pubkey) => (*pubkey, *blinding_point),
724 IntroductionNode::DirectedShortChannelId(..) => {
725 return Err(SendError::UnresolvedIntroductionNode);
731 let (packet_payloads, packet_keys) = packet_payloads_and_keys(
732 &secp_ctx, &intermediate_nodes, destination, contents, reply_path, &blinding_secret
735 let prng_seed = entropy_source.get_secure_random_bytes();
736 let onion_routing_packet = construct_onion_message_packet(
737 packet_payloads, packet_keys, prng_seed).map_err(|()| SendError::TooBigPacket)?;
739 let message = OnionMessage { blinding_point, onion_routing_packet };
740 Ok((first_node_id, message, first_node_addresses))
743 /// Decode one layer of an incoming [`OnionMessage`].
745 /// Returns either the next layer of the onion for forwarding or the decrypted content for the
747 pub fn peel_onion_message<NS: Deref, L: Deref, CMH: Deref>(
748 msg: &OnionMessage, secp_ctx: &Secp256k1<secp256k1::All>, node_signer: NS, logger: L,
750 ) -> Result<PeeledOnion<<<CMH>::Target as CustomOnionMessageHandler>::CustomMessage>, ()>
752 NS::Target: NodeSigner,
754 CMH::Target: CustomOnionMessageHandler,
756 let control_tlvs_ss = match node_signer.ecdh(Recipient::Node, &msg.blinding_point, None) {
759 log_error!(logger, "Failed to retrieve node secret: {:?}", e);
763 let onion_decode_ss = {
764 let blinding_factor = {
765 let mut hmac = HmacEngine::<Sha256>::new(b"blinded_node_id");
766 hmac.input(control_tlvs_ss.as_ref());
767 Hmac::from_engine(hmac).to_byte_array()
769 match node_signer.ecdh(Recipient::Node, &msg.onion_routing_packet.public_key,
770 Some(&Scalar::from_be_bytes(blinding_factor).unwrap()))
772 Ok(ss) => ss.secret_bytes(),
774 log_trace!(logger, "Failed to compute onion packet shared secret");
779 match onion_utils::decode_next_untagged_hop(
780 onion_decode_ss, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
781 (control_tlvs_ss, custom_handler.deref(), logger.deref())
783 Ok((Payload::Receive::<ParsedOnionMessageContents<<<CMH as Deref>::Target as CustomOnionMessageHandler>::CustomMessage>> {
784 message, control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id }), reply_path,
786 Ok(PeeledOnion::Receive(message, path_id, reply_path))
788 Ok((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
789 next_hop, next_blinding_override
790 })), Some((next_hop_hmac, new_packet_bytes)))) => {
791 // TODO: we need to check whether `next_hop` is our node, in which case this is a dummy
792 // blinded hop and this onion message is destined for us. In this situation, we should keep
793 // unwrapping the onion layers to get to the final payload. Since we don't have the option
794 // of creating blinded paths with dummy hops currently, we should be ok to not handle this
796 let new_pubkey = match onion_utils::next_hop_pubkey(&secp_ctx, msg.onion_routing_packet.public_key, &onion_decode_ss) {
799 log_trace!(logger, "Failed to compute next hop packet pubkey: {}", e);
803 let outgoing_packet = Packet {
805 public_key: new_pubkey,
806 hop_data: new_packet_bytes,
809 let onion_message = OnionMessage {
810 blinding_point: match next_blinding_override {
811 Some(blinding_point) => blinding_point,
813 match onion_utils::next_hop_pubkey(
814 &secp_ctx, msg.blinding_point, control_tlvs_ss.as_ref()
818 log_trace!(logger, "Failed to compute next blinding point: {}", e);
824 onion_routing_packet: outgoing_packet,
827 Ok(PeeledOnion::Forward(next_hop, onion_message))
830 log_trace!(logger, "Errored decoding onion message packet: {:?}", e);
834 log_trace!(logger, "Received bogus onion message packet, either the sender encoded a final hop as a forwarding hop or vice versa");
840 impl<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, CMH: Deref>
841 OnionMessenger<ES, NS, L, NL, MR, OMH, CMH>
843 ES::Target: EntropySource,
844 NS::Target: NodeSigner,
846 NL::Target: NodeIdLookUp,
847 MR::Target: MessageRouter,
848 OMH::Target: OffersMessageHandler,
849 CMH::Target: CustomOnionMessageHandler,
851 /// Constructs a new `OnionMessenger` to send, forward, and delegate received onion messages to
852 /// their respective handlers.
854 entropy_source: ES, node_signer: NS, logger: L, node_id_lookup: NL, message_router: MR,
855 offers_handler: OMH, custom_handler: CMH
858 entropy_source, node_signer, logger, node_id_lookup, message_router,
859 offers_handler, custom_handler, false
863 /// Similar to [`Self::new`], but rather than dropping onion messages that are
864 /// intended to be forwarded to offline peers, we will intercept them for
865 /// later forwarding.
867 /// Interception flow:
868 /// 1. If an onion message for an offline peer is received, `OnionMessenger` will
869 /// generate an [`Event::OnionMessageIntercepted`]. Event handlers can
870 /// then choose to persist this onion message for later forwarding, or drop
872 /// 2. When the offline peer later comes back online, `OnionMessenger` will
873 /// generate an [`Event::OnionMessagePeerConnected`]. Event handlers will
874 /// then fetch all previously intercepted onion messages for this peer.
875 /// 3. Once the stored onion messages are fetched, they can finally be
876 /// forwarded to the now-online peer via [`Self::forward_onion_message`].
880 /// LDK will not rate limit how many [`Event::OnionMessageIntercepted`]s
881 /// are generated, so it is the caller's responsibility to limit how many
882 /// onion messages are persisted and only persist onion messages for relevant
884 pub fn new_with_offline_peer_interception(
885 entropy_source: ES, node_signer: NS, logger: L, node_id_lookup: NL,
886 message_router: MR, offers_handler: OMH, custom_handler: CMH
889 entropy_source, node_signer, logger, node_id_lookup, message_router,
890 offers_handler, custom_handler, true
895 entropy_source: ES, node_signer: NS, logger: L, node_id_lookup: NL,
896 message_router: MR, offers_handler: OMH, custom_handler: CMH,
897 intercept_messages_for_offline_peers: bool
899 let mut secp_ctx = Secp256k1::new();
900 secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
904 message_recipients: Mutex::new(new_hash_map()),
911 intercept_messages_for_offline_peers,
912 pending_events: Mutex::new(Vec::new()),
917 pub(crate) fn set_offers_handler(&mut self, offers_handler: OMH) {
918 self.offers_handler = offers_handler;
921 /// Sends an [`OnionMessage`] with the given `contents` to `destination`.
923 /// See [`OnionMessenger`] for example usage.
924 pub fn send_onion_message<T: OnionMessageContents>(
925 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>
926 ) -> Result<SendSuccess, SendError> {
927 self.find_path_and_enqueue_onion_message(
928 contents, destination, reply_path, format_args!("")
932 fn find_path_and_enqueue_onion_message<T: OnionMessageContents>(
933 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>,
934 log_suffix: fmt::Arguments
935 ) -> Result<SendSuccess, SendError> {
936 let mut logger = WithContext::from(&self.logger, None, None, None);
937 let result = self.find_path(destination).and_then(|path| {
938 let first_hop = path.intermediate_nodes.get(0).map(|p| *p);
939 logger = WithContext::from(&self.logger, first_hop, None, None);
940 self.enqueue_onion_message(path, contents, reply_path, log_suffix)
943 match result.as_ref() {
944 Err(SendError::GetNodeIdFailed) => {
945 log_warn!(logger, "Unable to retrieve node id {}", log_suffix);
947 Err(SendError::PathNotFound) => {
948 log_trace!(logger, "Failed to find path {}", log_suffix);
951 log_trace!(logger, "Failed sending onion message {}: {:?}", log_suffix, e);
953 Ok(SendSuccess::Buffered) => {
954 log_trace!(logger, "Buffered onion message {}", log_suffix);
956 Ok(SendSuccess::BufferedAwaitingConnection(node_id)) => {
959 "Buffered onion message waiting on peer connection {}: {}",
968 fn find_path(&self, destination: Destination) -> Result<OnionMessagePath, SendError> {
969 let sender = self.node_signer
970 .get_node_id(Recipient::Node)
971 .map_err(|_| SendError::GetNodeIdFailed)?;
973 let peers = self.message_recipients.lock().unwrap()
975 .filter(|(_, recipient)| matches!(recipient, OnionMessageRecipient::ConnectedPeer(_)))
976 .map(|(node_id, _)| *node_id)
980 .find_path(sender, peers, destination)
981 .map_err(|_| SendError::PathNotFound)
984 fn enqueue_onion_message<T: OnionMessageContents>(
985 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
986 log_suffix: fmt::Arguments
987 ) -> Result<SendSuccess, SendError> {
988 log_trace!(self.logger, "Constructing onion message {}: {:?}", log_suffix, contents);
990 let (first_node_id, onion_message, addresses) = create_onion_message(
991 &self.entropy_source, &self.node_signer, &self.node_id_lookup, &self.secp_ctx, path,
992 contents, reply_path,
995 let mut message_recipients = self.message_recipients.lock().unwrap();
996 if outbound_buffer_full(&first_node_id, &message_recipients) {
997 return Err(SendError::BufferFull);
1000 match message_recipients.entry(first_node_id) {
1001 hash_map::Entry::Vacant(e) => match addresses {
1002 None => Err(SendError::InvalidFirstHop(first_node_id)),
1003 Some(addresses) => {
1004 e.insert(OnionMessageRecipient::pending_connection(addresses))
1005 .enqueue_message(onion_message);
1006 Ok(SendSuccess::BufferedAwaitingConnection(first_node_id))
1009 hash_map::Entry::Occupied(mut e) => {
1010 e.get_mut().enqueue_message(onion_message);
1011 if e.get().is_connected() {
1012 Ok(SendSuccess::Buffered)
1014 Ok(SendSuccess::BufferedAwaitingConnection(first_node_id))
1020 /// Forwards an [`OnionMessage`] to `peer_node_id`. Useful if we initialized
1021 /// the [`OnionMessenger`] with [`Self::new_with_offline_peer_interception`]
1022 /// and want to forward a previously intercepted onion message to a peer that
1023 /// has just come online.
1024 pub fn forward_onion_message(
1025 &self, message: OnionMessage, peer_node_id: &PublicKey
1026 ) -> Result<(), SendError> {
1027 let mut message_recipients = self.message_recipients.lock().unwrap();
1028 if outbound_buffer_full(&peer_node_id, &message_recipients) {
1029 return Err(SendError::BufferFull);
1032 match message_recipients.entry(*peer_node_id) {
1033 hash_map::Entry::Occupied(mut e) if e.get().is_connected() => {
1034 e.get_mut().enqueue_message(message);
1037 _ => Err(SendError::InvalidFirstHop(*peer_node_id))
1041 #[cfg(any(test, feature = "_test_utils"))]
1042 pub fn send_onion_message_using_path<T: OnionMessageContents>(
1043 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>
1044 ) -> Result<SendSuccess, SendError> {
1045 self.enqueue_onion_message(path, contents, reply_path, format_args!(""))
1048 pub(crate) fn peel_onion_message(
1049 &self, msg: &OnionMessage
1050 ) -> Result<PeeledOnion<<<CMH>::Target as CustomOnionMessageHandler>::CustomMessage>, ()> {
1052 msg, &self.secp_ctx, &*self.node_signer, &*self.logger, &*self.custom_handler
1056 fn handle_onion_message_response<T: OnionMessageContents>(
1057 &self, response: ResponseInstruction<T>
1059 if let ResponseInstruction::WithoutReplyPath(response) = response {
1060 let message_type = response.message.msg_type();
1061 let _ = self.find_path_and_enqueue_onion_message(
1062 response.message, Destination::BlindedPath(response.reply_path), None,
1064 "when responding with {} to an onion message with path_id {:02x?}",
1073 pub(super) fn release_pending_msgs(&self) -> HashMap<PublicKey, VecDeque<OnionMessage>> {
1074 let mut message_recipients = self.message_recipients.lock().unwrap();
1075 let mut msgs = new_hash_map();
1076 // We don't want to disconnect the peers by removing them entirely from the original map, so we
1077 // release the pending message buffers individually.
1078 for (node_id, recipient) in &mut *message_recipients {
1079 msgs.insert(*node_id, recipient.release_pending_messages());
1084 fn enqueue_event(&self, event: Event) {
1085 const MAX_EVENTS_BUFFER_SIZE: usize = (1 << 10) * 256;
1086 let mut pending_events = self.pending_events.lock().unwrap();
1087 let total_buffered_bytes: usize = pending_events
1089 .map(|ev| ev.serialized_length())
1091 if total_buffered_bytes >= MAX_EVENTS_BUFFER_SIZE {
1092 log_trace!(self.logger, "Dropping event {:?}: buffer full", event);
1095 pending_events.push(event);
1099 fn outbound_buffer_full(peer_node_id: &PublicKey, buffer: &HashMap<PublicKey, OnionMessageRecipient>) -> bool {
1100 const MAX_TOTAL_BUFFER_SIZE: usize = (1 << 20) * 128;
1101 const MAX_PER_PEER_BUFFER_SIZE: usize = (1 << 10) * 256;
1102 let mut total_buffered_bytes = 0;
1103 let mut peer_buffered_bytes = 0;
1104 for (pk, peer_buf) in buffer {
1105 for om in peer_buf.pending_messages() {
1106 let om_len = om.serialized_length();
1107 if pk == peer_node_id {
1108 peer_buffered_bytes += om_len;
1110 total_buffered_bytes += om_len;
1112 if total_buffered_bytes >= MAX_TOTAL_BUFFER_SIZE ||
1113 peer_buffered_bytes >= MAX_PER_PEER_BUFFER_SIZE
1122 impl<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, CMH: Deref> EventsProvider
1123 for OnionMessenger<ES, NS, L, NL, MR, OMH, CMH>
1125 ES::Target: EntropySource,
1126 NS::Target: NodeSigner,
1128 NL::Target: NodeIdLookUp,
1129 MR::Target: MessageRouter,
1130 OMH::Target: OffersMessageHandler,
1131 CMH::Target: CustomOnionMessageHandler,
1133 fn process_pending_events<H: Deref>(&self, handler: H) where H::Target: EventHandler {
1134 for (node_id, recipient) in self.message_recipients.lock().unwrap().iter_mut() {
1135 if let OnionMessageRecipient::PendingConnection(_, addresses, _) = recipient {
1136 if let Some(addresses) = addresses.take() {
1137 handler.handle_event(Event::ConnectionNeeded { node_id: *node_id, addresses });
1141 let mut events = Vec::new();
1142 core::mem::swap(&mut *self.pending_events.lock().unwrap(), &mut events);
1144 handler.handle_event(ev);
1149 impl<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, CMH: Deref> OnionMessageHandler
1150 for OnionMessenger<ES, NS, L, NL, MR, OMH, CMH>
1152 ES::Target: EntropySource,
1153 NS::Target: NodeSigner,
1155 NL::Target: NodeIdLookUp,
1156 MR::Target: MessageRouter,
1157 OMH::Target: OffersMessageHandler,
1158 CMH::Target: CustomOnionMessageHandler,
1160 fn handle_onion_message(&self, peer_node_id: &PublicKey, msg: &OnionMessage) {
1161 let logger = WithContext::from(&self.logger, Some(*peer_node_id), None, None);
1162 match self.peel_onion_message(msg) {
1163 Ok(PeeledOnion::Receive(message, path_id, reply_path)) => {
1166 "Received an onion message with path_id {:02x?} and {} reply_path: {:?}",
1167 path_id, if reply_path.is_some() { "a" } else { "no" }, message);
1170 ParsedOnionMessageContents::Offers(msg) => {
1171 let responder = reply_path.map(
1172 |reply_path| Responder::new(reply_path, path_id)
1174 let response_instructions = self.offers_handler.handle_message(msg, responder);
1175 self.handle_onion_message_response(response_instructions);
1177 ParsedOnionMessageContents::Custom(msg) => {
1178 let responder = reply_path.map(
1179 |reply_path| Responder::new(reply_path, path_id)
1181 let response_instructions = self.custom_handler.handle_custom_message(msg, responder);
1182 self.handle_onion_message_response(response_instructions);
1186 Ok(PeeledOnion::Forward(next_hop, onion_message)) => {
1187 let next_node_id = match next_hop {
1188 NextMessageHop::NodeId(pubkey) => pubkey,
1189 NextMessageHop::ShortChannelId(scid) => match self.node_id_lookup.next_node_id(scid) {
1190 Some(pubkey) => pubkey,
1192 log_trace!(self.logger, "Dropping forwarded onion messager: unable to resolve next hop using SCID {}", scid);
1198 let mut message_recipients = self.message_recipients.lock().unwrap();
1199 if outbound_buffer_full(&next_node_id, &message_recipients) {
1202 "Dropping forwarded onion message to peer {}: outbound buffer full",
1209 .entry(next_node_id)
1210 .or_insert_with(|| OnionMessageRecipient::ConnectedPeer(VecDeque::new()));
1212 match message_recipients.entry(next_node_id) {
1213 hash_map::Entry::Occupied(mut e) if matches!(
1214 e.get(), OnionMessageRecipient::ConnectedPeer(..)
1216 e.get_mut().enqueue_message(onion_message);
1217 log_trace!(logger, "Forwarding an onion message to peer {}", next_node_id);
1219 _ if self.intercept_messages_for_offline_peers => {
1221 Event::OnionMessageIntercepted {
1222 peer_node_id: next_node_id, message: onion_message
1229 "Dropping forwarded onion message to disconnected peer {}",
1236 log_error!(logger, "Failed to process onion message {:?}", e);
1241 fn peer_connected(&self, their_node_id: &PublicKey, init: &msgs::Init, _inbound: bool) -> Result<(), ()> {
1242 if init.features.supports_onion_messages() {
1243 self.message_recipients.lock().unwrap()
1244 .entry(*their_node_id)
1245 .or_insert_with(|| OnionMessageRecipient::ConnectedPeer(VecDeque::new()))
1247 if self.intercept_messages_for_offline_peers {
1249 Event::OnionMessagePeerConnected { peer_node_id: *their_node_id }
1253 self.message_recipients.lock().unwrap().remove(their_node_id);
1259 fn peer_disconnected(&self, their_node_id: &PublicKey) {
1260 match self.message_recipients.lock().unwrap().remove(their_node_id) {
1261 Some(OnionMessageRecipient::ConnectedPeer(..)) => {},
1262 Some(_) => debug_assert!(false),
1267 fn timer_tick_occurred(&self) {
1268 let mut message_recipients = self.message_recipients.lock().unwrap();
1270 // Drop any pending recipients since the last call to avoid retaining buffered messages for
1272 message_recipients.retain(|_, recipient| match recipient {
1273 OnionMessageRecipient::PendingConnection(_, None, ticks) => *ticks < MAX_TIMER_TICKS,
1274 OnionMessageRecipient::PendingConnection(_, Some(_), _) => true,
1278 // Increment a timer tick for pending recipients so that their buffered messages are dropped
1279 // at MAX_TIMER_TICKS.
1280 for recipient in message_recipients.values_mut() {
1281 if let OnionMessageRecipient::PendingConnection(_, None, ticks) = recipient {
1287 fn provided_node_features(&self) -> NodeFeatures {
1288 let mut features = NodeFeatures::empty();
1289 features.set_onion_messages_optional();
1293 fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
1294 let mut features = InitFeatures::empty();
1295 features.set_onion_messages_optional();
1299 // Before returning any messages to send for the peer, this method will see if any messages were
1300 // enqueued in the handler by users, find a path to the corresponding blinded path's introduction
1301 // node, and then enqueue the message for sending to the first peer in the full path.
1302 fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<OnionMessage> {
1303 // Enqueue any initiating `OffersMessage`s to send.
1304 for message in self.offers_handler.release_pending_messages() {
1305 #[cfg(not(c_bindings))]
1306 let PendingOnionMessage { contents, destination, reply_path } = message;
1308 let (contents, destination, reply_path) = message;
1309 let _ = self.find_path_and_enqueue_onion_message(
1310 contents, destination, reply_path, format_args!("when sending OffersMessage")
1314 // Enqueue any initiating `CustomMessage`s to send.
1315 for message in self.custom_handler.release_pending_custom_messages() {
1316 #[cfg(not(c_bindings))]
1317 let PendingOnionMessage { contents, destination, reply_path } = message;
1319 let (contents, destination, reply_path) = message;
1320 let _ = self.find_path_and_enqueue_onion_message(
1321 contents, destination, reply_path, format_args!("when sending CustomMessage")
1325 self.message_recipients.lock().unwrap()
1326 .get_mut(&peer_node_id)
1327 .and_then(|buffer| buffer.dequeue_message())
1331 // TODO: parameterize the below Simple* types with OnionMessenger and handle the messages it
1333 /// Useful for simplifying the parameters of [`SimpleArcChannelManager`] and
1334 /// [`SimpleArcPeerManager`]. See their docs for more details.
1336 /// This is not exported to bindings users as type aliases aren't supported in most languages.
1338 /// [`SimpleArcChannelManager`]: crate::ln::channelmanager::SimpleArcChannelManager
1339 /// [`SimpleArcPeerManager`]: crate::ln::peer_handler::SimpleArcPeerManager
1340 #[cfg(not(c_bindings))]
1341 pub type SimpleArcOnionMessenger<M, T, F, L> = OnionMessenger<
1345 Arc<SimpleArcChannelManager<M, T, F, L>>,
1346 Arc<DefaultMessageRouter<Arc<NetworkGraph<Arc<L>>>, Arc<L>, Arc<KeysManager>>>,
1347 Arc<SimpleArcChannelManager<M, T, F, L>>,
1348 IgnoringMessageHandler
1351 /// Useful for simplifying the parameters of [`SimpleRefChannelManager`] and
1352 /// [`SimpleRefPeerManager`]. See their docs for more details.
1354 /// This is not exported to bindings users as type aliases aren't supported in most languages.
1356 /// [`SimpleRefChannelManager`]: crate::ln::channelmanager::SimpleRefChannelManager
1357 /// [`SimpleRefPeerManager`]: crate::ln::peer_handler::SimpleRefPeerManager
1358 #[cfg(not(c_bindings))]
1359 pub type SimpleRefOnionMessenger<
1360 'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, 'i, 'j, M, T, F, L
1365 &'i SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, M, T, F, L>,
1366 &'j DefaultMessageRouter<&'g NetworkGraph<&'b L>, &'b L, &'a KeysManager>,
1367 &'i SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, M, T, F, L>,
1368 IgnoringMessageHandler
1371 /// Construct onion packet payloads and keys for sending an onion message along the given
1372 /// `unblinded_path` to the given `destination`.
1373 fn packet_payloads_and_keys<T: OnionMessageContents, S: secp256k1::Signing + secp256k1::Verification>(
1374 secp_ctx: &Secp256k1<S>, unblinded_path: &[PublicKey], destination: Destination, message: T,
1375 mut reply_path: Option<BlindedPath>, session_priv: &SecretKey
1376 ) -> Result<(Vec<(Payload<T>, [u8; 32])>, Vec<onion_utils::OnionKeys>), SendError> {
1377 let num_hops = unblinded_path.len() + destination.num_hops();
1378 let mut payloads = Vec::with_capacity(num_hops);
1379 let mut onion_packet_keys = Vec::with_capacity(num_hops);
1381 let (mut intro_node_id_blinding_pt, num_blinded_hops) = match &destination {
1382 Destination::Node(_) => (None, 0),
1383 Destination::BlindedPath(BlindedPath { introduction_node, blinding_point, blinded_hops }) => {
1384 let introduction_node_id = match introduction_node {
1385 IntroductionNode::NodeId(pubkey) => pubkey,
1386 IntroductionNode::DirectedShortChannelId(..) => {
1387 return Err(SendError::UnresolvedIntroductionNode);
1390 (Some((*introduction_node_id, *blinding_point)), blinded_hops.len())
1393 let num_unblinded_hops = num_hops - num_blinded_hops;
1395 let mut unblinded_path_idx = 0;
1396 let mut blinded_path_idx = 0;
1397 let mut prev_control_tlvs_ss = None;
1398 let mut final_control_tlvs = None;
1399 utils::construct_keys_callback(secp_ctx, unblinded_path.iter(), Some(destination), session_priv,
1400 |_, onion_packet_ss, ephemeral_pubkey, control_tlvs_ss, unblinded_pk_opt, enc_payload_opt| {
1401 if num_unblinded_hops != 0 && unblinded_path_idx < num_unblinded_hops {
1402 if let Some(ss) = prev_control_tlvs_ss.take() {
1403 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(
1405 next_hop: NextMessageHop::NodeId(unblinded_pk_opt.unwrap()),
1406 next_blinding_override: None,
1410 prev_control_tlvs_ss = Some(control_tlvs_ss);
1411 unblinded_path_idx += 1;
1412 } else if let Some((intro_node_id, blinding_pt)) = intro_node_id_blinding_pt.take() {
1413 if let Some(control_tlvs_ss) = prev_control_tlvs_ss.take() {
1414 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
1415 next_hop: NextMessageHop::NodeId(intro_node_id),
1416 next_blinding_override: Some(blinding_pt),
1417 })), control_tlvs_ss));
1420 if blinded_path_idx < num_blinded_hops.saturating_sub(1) && enc_payload_opt.is_some() {
1421 payloads.push((Payload::Forward(ForwardControlTlvs::Blinded(enc_payload_opt.unwrap())),
1423 blinded_path_idx += 1;
1424 } else if let Some(encrypted_payload) = enc_payload_opt {
1425 final_control_tlvs = Some(ReceiveControlTlvs::Blinded(encrypted_payload));
1426 prev_control_tlvs_ss = Some(control_tlvs_ss);
1429 let (rho, mu) = onion_utils::gen_rho_mu_from_shared_secret(onion_packet_ss.as_ref());
1430 onion_packet_keys.push(onion_utils::OnionKeys {
1432 shared_secret: onion_packet_ss,
1434 blinding_factor: [0; 32],
1440 ).map_err(|e| SendError::Secp256k1(e))?;
1442 if let Some(control_tlvs) = final_control_tlvs {
1443 payloads.push((Payload::Receive {
1445 reply_path: reply_path.take(),
1447 }, prev_control_tlvs_ss.unwrap()));
1449 payloads.push((Payload::Receive {
1450 control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id: None, }),
1451 reply_path: reply_path.take(),
1453 }, prev_control_tlvs_ss.unwrap()));
1456 Ok((payloads, onion_packet_keys))
1459 /// Errors if the serialized payload size exceeds onion_message::BIG_PACKET_HOP_DATA_LEN
1460 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, ()> {
1462 // "`len` allows larger messages to be sent than the standard 1300 bytes allowed for an HTLC
1463 // onion, but this should be used sparingly as it is reduces anonymity set, hence the
1464 // recommendation that it either look like an HTLC onion, or if larger, be a fixed size."
1465 let payloads_ser_len = onion_utils::payloads_serialized_length(&payloads);
1466 let hop_data_len = if payloads_ser_len <= SMALL_PACKET_HOP_DATA_LEN {
1467 SMALL_PACKET_HOP_DATA_LEN
1468 } else if payloads_ser_len <= BIG_PACKET_HOP_DATA_LEN {
1469 BIG_PACKET_HOP_DATA_LEN
1470 } else { return Err(()) };
1472 onion_utils::construct_onion_message_packet::<_, _>(
1473 payloads, onion_keys, prng_seed, hop_data_len)