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<PublicKey>, _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<PublicKey>, 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<PublicKey>, 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.iter()
425 // Limit to peers with announced channels
428 .node(&NodeId::from_pubkey(pubkey))
429 .filter(|info| info.channels.len() >= MIN_PEER_CHANNELS)
430 .map(|info| (*pubkey, 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(|(node_id, _, _)| vec![ForwardNode { node_id, short_channel_id: None }])
443 .map(|intermediate_nodes| {
444 BlindedPath::new_for_message(
445 &intermediate_nodes, recipient, &*self.entropy_source, secp_ctx
449 .collect::<Result<Vec<_>, _>>();
452 Ok(paths) if !paths.is_empty() => Ok(paths),
454 if is_recipient_announced {
455 BlindedPath::one_hop_for_message(recipient, &*self.entropy_source, secp_ctx)
456 .map(|path| vec![path])
465 /// A path for sending an [`OnionMessage`].
467 pub struct OnionMessagePath {
468 /// Nodes on the path between the sender and the destination.
469 pub intermediate_nodes: Vec<PublicKey>,
471 /// The recipient of the message.
472 pub destination: Destination,
474 /// Addresses that may be used to connect to [`OnionMessagePath::first_node`].
476 /// Only needs to be set if a connection to the node is required. [`OnionMessenger`] may use
477 /// this to initiate such a connection.
478 pub first_node_addresses: Option<Vec<SocketAddress>>,
481 impl OnionMessagePath {
482 /// Returns the first node in the path.
483 pub fn first_node(&self) -> Option<PublicKey> {
484 self.intermediate_nodes
487 .or_else(|| self.destination.first_node())
491 /// The destination of an onion message.
492 #[derive(Clone, Hash, Debug, PartialEq, Eq)]
493 pub enum Destination {
494 /// We're sending this onion message to a node.
496 /// We're sending this onion message to a blinded path.
497 BlindedPath(BlindedPath),
501 /// Attempts to resolve the [`IntroductionNode::DirectedShortChannelId`] of a
502 /// [`Destination::BlindedPath`] to a [`IntroductionNode::NodeId`], if applicable, using the
503 /// provided [`ReadOnlyNetworkGraph`].
504 pub fn resolve(&mut self, network_graph: &ReadOnlyNetworkGraph) {
505 if let Destination::BlindedPath(path) = self {
506 if let IntroductionNode::DirectedShortChannelId(..) = path.introduction_node {
507 if let Some(pubkey) = path
508 .public_introduction_node_id(network_graph)
509 .and_then(|node_id| node_id.as_pubkey().ok())
511 path.introduction_node = IntroductionNode::NodeId(pubkey);
517 pub(super) fn num_hops(&self) -> usize {
519 Destination::Node(_) => 1,
520 Destination::BlindedPath(BlindedPath { blinded_hops, .. }) => blinded_hops.len(),
524 fn first_node(&self) -> Option<PublicKey> {
526 Destination::Node(node_id) => Some(*node_id),
527 Destination::BlindedPath(BlindedPath { introduction_node, .. }) => {
528 match introduction_node {
529 IntroductionNode::NodeId(pubkey) => Some(*pubkey),
530 IntroductionNode::DirectedShortChannelId(..) => None,
537 /// Result of successfully [sending an onion message].
539 /// [sending an onion message]: OnionMessenger::send_onion_message
540 #[derive(Clone, Hash, Debug, PartialEq, Eq)]
541 pub enum SendSuccess {
542 /// The message was buffered and will be sent once it is processed by
543 /// [`OnionMessageHandler::next_onion_message_for_peer`].
545 /// The message was buffered and will be sent once the node is connected as a peer and it is
546 /// processed by [`OnionMessageHandler::next_onion_message_for_peer`].
547 BufferedAwaitingConnection(PublicKey),
550 /// Errors that may occur when [sending an onion message].
552 /// [sending an onion message]: OnionMessenger::send_onion_message
553 #[derive(Clone, Hash, Debug, PartialEq, Eq)]
555 /// Errored computing onion message packet keys.
556 Secp256k1(secp256k1::Error),
557 /// Because implementations such as Eclair will drop onion messages where the message packet
558 /// exceeds 32834 bytes, we refuse to send messages where the packet exceeds this size.
560 /// The provided [`Destination`] was an invalid [`BlindedPath`] due to not having any blinded
563 /// The first hop is not a peer and doesn't have a known [`SocketAddress`].
564 InvalidFirstHop(PublicKey),
565 /// A path from the sender to the destination could not be found by the [`MessageRouter`].
567 /// Onion message contents must have a TLV type >= 64.
569 /// Our next-hop peer's buffer was full or our total outbound buffer was full.
571 /// Failed to retrieve our node id from the provided [`NodeSigner`].
573 /// [`NodeSigner`]: crate::sign::NodeSigner
575 /// The provided [`Destination`] has a blinded path with an unresolved introduction node. An
576 /// attempt to resolve it in the [`MessageRouter`] when finding an [`OnionMessagePath`] likely
578 UnresolvedIntroductionNode,
579 /// We attempted to send to a blinded path where we are the introduction node, and failed to
580 /// advance the blinded path to make the second hop the new introduction node. Either
581 /// [`NodeSigner::ecdh`] failed, we failed to tweak the current blinding point to get the
582 /// new blinding point, or we were attempting to send to ourselves.
583 BlindedPathAdvanceFailed,
586 /// Handler for custom onion messages. If you are using [`SimpleArcOnionMessenger`],
587 /// [`SimpleRefOnionMessenger`], or prefer to ignore inbound custom onion messages,
588 /// [`IgnoringMessageHandler`] must be provided to [`OnionMessenger::new`]. Otherwise, a custom
589 /// implementation of this trait must be provided, with [`CustomMessage`] specifying the supported
592 /// See [`OnionMessenger`] for example usage.
594 /// [`IgnoringMessageHandler`]: crate::ln::peer_handler::IgnoringMessageHandler
595 /// [`CustomMessage`]: Self::CustomMessage
596 pub trait CustomOnionMessageHandler {
597 /// The message known to the handler. To support multiple message types, you may want to make this
598 /// an enum with a variant for each supported message.
599 type CustomMessage: OnionMessageContents;
601 /// Called with the custom message that was received, returning a response to send, if any.
603 /// The returned [`Self::CustomMessage`], if any, is enqueued to be sent by [`OnionMessenger`].
604 fn handle_custom_message(&self, message: Self::CustomMessage, responder: Option<Responder>) -> ResponseInstruction<Self::CustomMessage>;
606 /// Read a custom message of type `message_type` from `buffer`, returning `Ok(None)` if the
607 /// message type is unknown.
608 fn read_custom_message<R: io::Read>(&self, message_type: u64, buffer: &mut R) -> Result<Option<Self::CustomMessage>, msgs::DecodeError>;
610 /// Releases any [`Self::CustomMessage`]s that need to be sent.
612 /// Typically, this is used for messages initiating a message flow rather than in response to
613 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
614 #[cfg(not(c_bindings))]
615 fn release_pending_custom_messages(&self) -> Vec<PendingOnionMessage<Self::CustomMessage>>;
617 /// Releases any [`Self::CustomMessage`]s that need to be sent.
619 /// Typically, this is used for messages initiating a message flow rather than in response to
620 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
622 fn release_pending_custom_messages(&self) -> Vec<(Self::CustomMessage, Destination, Option<BlindedPath>)>;
625 /// A processed incoming onion message, containing either a Forward (another onion message)
626 /// or a Receive payload with decrypted contents.
627 #[derive(Clone, Debug)]
628 pub enum PeeledOnion<T: OnionMessageContents> {
629 /// Forwarded onion, with the next node id and a new onion
630 Forward(NextMessageHop, OnionMessage),
631 /// Received onion message, with decrypted contents, path_id, and reply path
632 Receive(ParsedOnionMessageContents<T>, Option<[u8; 32]>, Option<BlindedPath>)
636 /// Creates an [`OnionMessage`] with the given `contents` for sending to the destination of
637 /// `path`, first calling [`Destination::resolve`] on `path.destination` with the given
638 /// [`ReadOnlyNetworkGraph`].
640 /// Returns the node id of the peer to send the message to, the message itself, and any addresses
641 /// needed to connect to the first node.
642 pub fn create_onion_message_resolving_destination<
643 ES: Deref, NS: Deref, NL: Deref, T: OnionMessageContents
645 entropy_source: &ES, node_signer: &NS, node_id_lookup: &NL,
646 network_graph: &ReadOnlyNetworkGraph, secp_ctx: &Secp256k1<secp256k1::All>,
647 mut path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
648 ) -> Result<(PublicKey, OnionMessage, Option<Vec<SocketAddress>>), SendError>
650 ES::Target: EntropySource,
651 NS::Target: NodeSigner,
652 NL::Target: NodeIdLookUp,
654 path.destination.resolve(network_graph);
655 create_onion_message(
656 entropy_source, node_signer, node_id_lookup, secp_ctx, path, contents, reply_path,
660 /// Creates an [`OnionMessage`] with the given `contents` for sending to the destination of
663 /// Returns the node id of the peer to send the message to, the message itself, and any addresses
664 /// needed to connect to the first node.
666 /// Returns [`SendError::UnresolvedIntroductionNode`] if:
667 /// - `destination` contains a blinded path with an [`IntroductionNode::DirectedShortChannelId`],
668 /// - unless it can be resolved by [`NodeIdLookUp::next_node_id`].
669 /// Use [`create_onion_message_resolving_destination`] instead to resolve the introduction node
670 /// first with a [`ReadOnlyNetworkGraph`].
671 pub fn create_onion_message<ES: Deref, NS: Deref, NL: Deref, T: OnionMessageContents>(
672 entropy_source: &ES, node_signer: &NS, node_id_lookup: &NL,
673 secp_ctx: &Secp256k1<secp256k1::All>, path: OnionMessagePath, contents: T,
674 reply_path: Option<BlindedPath>,
675 ) -> Result<(PublicKey, OnionMessage, Option<Vec<SocketAddress>>), SendError>
677 ES::Target: EntropySource,
678 NS::Target: NodeSigner,
679 NL::Target: NodeIdLookUp,
681 let OnionMessagePath { intermediate_nodes, mut destination, first_node_addresses } = path;
682 if let Destination::BlindedPath(BlindedPath { ref blinded_hops, .. }) = destination {
683 if blinded_hops.is_empty() {
684 return Err(SendError::TooFewBlindedHops);
688 if contents.tlv_type() < 64 { return Err(SendError::InvalidMessage) }
690 // If we are sending straight to a blinded path and we are the introduction node, we need to
691 // advance the blinded path by 1 hop so the second hop is the new introduction node.
692 if intermediate_nodes.len() == 0 {
693 if let Destination::BlindedPath(ref mut blinded_path) = destination {
694 let our_node_id = node_signer.get_node_id(Recipient::Node)
695 .map_err(|()| SendError::GetNodeIdFailed)?;
696 let introduction_node_id = match blinded_path.introduction_node {
697 IntroductionNode::NodeId(pubkey) => pubkey,
698 IntroductionNode::DirectedShortChannelId(direction, scid) => {
699 match node_id_lookup.next_node_id(scid) {
700 Some(next_node_id) => *direction.select_pubkey(&our_node_id, &next_node_id),
701 None => return Err(SendError::UnresolvedIntroductionNode),
705 if introduction_node_id == our_node_id {
706 advance_path_by_one(blinded_path, node_signer, node_id_lookup, &secp_ctx)
707 .map_err(|()| SendError::BlindedPathAdvanceFailed)?;
712 let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
713 let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
714 let (first_node_id, blinding_point) = if let Some(first_node_id) = intermediate_nodes.first() {
715 (*first_node_id, PublicKey::from_secret_key(&secp_ctx, &blinding_secret))
718 Destination::Node(pk) => (*pk, PublicKey::from_secret_key(&secp_ctx, &blinding_secret)),
719 Destination::BlindedPath(BlindedPath { introduction_node, blinding_point, .. }) => {
720 match introduction_node {
721 IntroductionNode::NodeId(pubkey) => (*pubkey, *blinding_point),
722 IntroductionNode::DirectedShortChannelId(..) => {
723 return Err(SendError::UnresolvedIntroductionNode);
729 let (packet_payloads, packet_keys) = packet_payloads_and_keys(
730 &secp_ctx, &intermediate_nodes, destination, contents, reply_path, &blinding_secret
733 let prng_seed = entropy_source.get_secure_random_bytes();
734 let onion_routing_packet = construct_onion_message_packet(
735 packet_payloads, packet_keys, prng_seed).map_err(|()| SendError::TooBigPacket)?;
737 let message = OnionMessage { blinding_point, onion_routing_packet };
738 Ok((first_node_id, message, first_node_addresses))
741 /// Decode one layer of an incoming [`OnionMessage`].
743 /// Returns either the next layer of the onion for forwarding or the decrypted content for the
745 pub fn peel_onion_message<NS: Deref, L: Deref, CMH: Deref>(
746 msg: &OnionMessage, secp_ctx: &Secp256k1<secp256k1::All>, node_signer: NS, logger: L,
748 ) -> Result<PeeledOnion<<<CMH>::Target as CustomOnionMessageHandler>::CustomMessage>, ()>
750 NS::Target: NodeSigner,
752 CMH::Target: CustomOnionMessageHandler,
754 let control_tlvs_ss = match node_signer.ecdh(Recipient::Node, &msg.blinding_point, None) {
757 log_error!(logger, "Failed to retrieve node secret: {:?}", e);
761 let onion_decode_ss = {
762 let blinding_factor = {
763 let mut hmac = HmacEngine::<Sha256>::new(b"blinded_node_id");
764 hmac.input(control_tlvs_ss.as_ref());
765 Hmac::from_engine(hmac).to_byte_array()
767 match node_signer.ecdh(Recipient::Node, &msg.onion_routing_packet.public_key,
768 Some(&Scalar::from_be_bytes(blinding_factor).unwrap()))
770 Ok(ss) => ss.secret_bytes(),
772 log_trace!(logger, "Failed to compute onion packet shared secret");
777 match onion_utils::decode_next_untagged_hop(
778 onion_decode_ss, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
779 (control_tlvs_ss, custom_handler.deref(), logger.deref())
781 Ok((Payload::Receive::<ParsedOnionMessageContents<<<CMH as Deref>::Target as CustomOnionMessageHandler>::CustomMessage>> {
782 message, control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id }), reply_path,
784 Ok(PeeledOnion::Receive(message, path_id, reply_path))
786 Ok((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
787 next_hop, next_blinding_override
788 })), Some((next_hop_hmac, new_packet_bytes)))) => {
789 // TODO: we need to check whether `next_hop` is our node, in which case this is a dummy
790 // blinded hop and this onion message is destined for us. In this situation, we should keep
791 // unwrapping the onion layers to get to the final payload. Since we don't have the option
792 // of creating blinded paths with dummy hops currently, we should be ok to not handle this
794 let new_pubkey = match onion_utils::next_hop_pubkey(&secp_ctx, msg.onion_routing_packet.public_key, &onion_decode_ss) {
797 log_trace!(logger, "Failed to compute next hop packet pubkey: {}", e);
801 let outgoing_packet = Packet {
803 public_key: new_pubkey,
804 hop_data: new_packet_bytes,
807 let onion_message = OnionMessage {
808 blinding_point: match next_blinding_override {
809 Some(blinding_point) => blinding_point,
811 match onion_utils::next_hop_pubkey(
812 &secp_ctx, msg.blinding_point, control_tlvs_ss.as_ref()
816 log_trace!(logger, "Failed to compute next blinding point: {}", e);
822 onion_routing_packet: outgoing_packet,
825 Ok(PeeledOnion::Forward(next_hop, onion_message))
828 log_trace!(logger, "Errored decoding onion message packet: {:?}", e);
832 log_trace!(logger, "Received bogus onion message packet, either the sender encoded a final hop as a forwarding hop or vice versa");
838 impl<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, CMH: Deref>
839 OnionMessenger<ES, NS, L, NL, MR, OMH, CMH>
841 ES::Target: EntropySource,
842 NS::Target: NodeSigner,
844 NL::Target: NodeIdLookUp,
845 MR::Target: MessageRouter,
846 OMH::Target: OffersMessageHandler,
847 CMH::Target: CustomOnionMessageHandler,
849 /// Constructs a new `OnionMessenger` to send, forward, and delegate received onion messages to
850 /// their respective handlers.
852 entropy_source: ES, node_signer: NS, logger: L, node_id_lookup: NL, message_router: MR,
853 offers_handler: OMH, custom_handler: CMH
856 entropy_source, node_signer, logger, node_id_lookup, message_router,
857 offers_handler, custom_handler, false
861 /// Similar to [`Self::new`], but rather than dropping onion messages that are
862 /// intended to be forwarded to offline peers, we will intercept them for
863 /// later forwarding.
865 /// Interception flow:
866 /// 1. If an onion message for an offline peer is received, `OnionMessenger` will
867 /// generate an [`Event::OnionMessageIntercepted`]. Event handlers can
868 /// then choose to persist this onion message for later forwarding, or drop
870 /// 2. When the offline peer later comes back online, `OnionMessenger` will
871 /// generate an [`Event::OnionMessagePeerConnected`]. Event handlers will
872 /// then fetch all previously intercepted onion messages for this peer.
873 /// 3. Once the stored onion messages are fetched, they can finally be
874 /// forwarded to the now-online peer via [`Self::forward_onion_message`].
878 /// LDK will not rate limit how many [`Event::OnionMessageIntercepted`]s
879 /// are generated, so it is the caller's responsibility to limit how many
880 /// onion messages are persisted and only persist onion messages for relevant
882 pub fn new_with_offline_peer_interception(
883 entropy_source: ES, node_signer: NS, logger: L, node_id_lookup: NL,
884 message_router: MR, offers_handler: OMH, custom_handler: CMH
887 entropy_source, node_signer, logger, node_id_lookup, message_router,
888 offers_handler, custom_handler, true
893 entropy_source: ES, node_signer: NS, logger: L, node_id_lookup: NL,
894 message_router: MR, offers_handler: OMH, custom_handler: CMH,
895 intercept_messages_for_offline_peers: bool
897 let mut secp_ctx = Secp256k1::new();
898 secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
902 message_recipients: Mutex::new(new_hash_map()),
909 intercept_messages_for_offline_peers,
910 pending_events: Mutex::new(Vec::new()),
915 pub(crate) fn set_offers_handler(&mut self, offers_handler: OMH) {
916 self.offers_handler = offers_handler;
919 /// Sends an [`OnionMessage`] with the given `contents` to `destination`.
921 /// See [`OnionMessenger`] for example usage.
922 pub fn send_onion_message<T: OnionMessageContents>(
923 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>
924 ) -> Result<SendSuccess, SendError> {
925 self.find_path_and_enqueue_onion_message(
926 contents, destination, reply_path, format_args!("")
930 fn find_path_and_enqueue_onion_message<T: OnionMessageContents>(
931 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>,
932 log_suffix: fmt::Arguments
933 ) -> Result<SendSuccess, SendError> {
934 let mut logger = WithContext::from(&self.logger, None, None, None);
935 let result = self.find_path(destination).and_then(|path| {
936 let first_hop = path.intermediate_nodes.get(0).map(|p| *p);
937 logger = WithContext::from(&self.logger, first_hop, None, None);
938 self.enqueue_onion_message(path, contents, reply_path, log_suffix)
941 match result.as_ref() {
942 Err(SendError::GetNodeIdFailed) => {
943 log_warn!(logger, "Unable to retrieve node id {}", log_suffix);
945 Err(SendError::PathNotFound) => {
946 log_trace!(logger, "Failed to find path {}", log_suffix);
949 log_trace!(logger, "Failed sending onion message {}: {:?}", log_suffix, e);
951 Ok(SendSuccess::Buffered) => {
952 log_trace!(logger, "Buffered onion message {}", log_suffix);
954 Ok(SendSuccess::BufferedAwaitingConnection(node_id)) => {
957 "Buffered onion message waiting on peer connection {}: {}",
966 fn find_path(&self, destination: Destination) -> Result<OnionMessagePath, SendError> {
967 let sender = self.node_signer
968 .get_node_id(Recipient::Node)
969 .map_err(|_| SendError::GetNodeIdFailed)?;
971 let peers = self.message_recipients.lock().unwrap()
973 .filter(|(_, recipient)| matches!(recipient, OnionMessageRecipient::ConnectedPeer(_)))
974 .map(|(node_id, _)| *node_id)
978 .find_path(sender, peers, destination)
979 .map_err(|_| SendError::PathNotFound)
982 fn enqueue_onion_message<T: OnionMessageContents>(
983 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
984 log_suffix: fmt::Arguments
985 ) -> Result<SendSuccess, SendError> {
986 log_trace!(self.logger, "Constructing onion message {}: {:?}", log_suffix, contents);
988 let (first_node_id, onion_message, addresses) = create_onion_message(
989 &self.entropy_source, &self.node_signer, &self.node_id_lookup, &self.secp_ctx, path,
990 contents, reply_path,
993 let mut message_recipients = self.message_recipients.lock().unwrap();
994 if outbound_buffer_full(&first_node_id, &message_recipients) {
995 return Err(SendError::BufferFull);
998 match message_recipients.entry(first_node_id) {
999 hash_map::Entry::Vacant(e) => match addresses {
1000 None => Err(SendError::InvalidFirstHop(first_node_id)),
1001 Some(addresses) => {
1002 e.insert(OnionMessageRecipient::pending_connection(addresses))
1003 .enqueue_message(onion_message);
1004 Ok(SendSuccess::BufferedAwaitingConnection(first_node_id))
1007 hash_map::Entry::Occupied(mut e) => {
1008 e.get_mut().enqueue_message(onion_message);
1009 if e.get().is_connected() {
1010 Ok(SendSuccess::Buffered)
1012 Ok(SendSuccess::BufferedAwaitingConnection(first_node_id))
1018 /// Forwards an [`OnionMessage`] to `peer_node_id`. Useful if we initialized
1019 /// the [`OnionMessenger`] with [`Self::new_with_offline_peer_interception`]
1020 /// and want to forward a previously intercepted onion message to a peer that
1021 /// has just come online.
1022 pub fn forward_onion_message(
1023 &self, message: OnionMessage, peer_node_id: &PublicKey
1024 ) -> Result<(), SendError> {
1025 let mut message_recipients = self.message_recipients.lock().unwrap();
1026 if outbound_buffer_full(&peer_node_id, &message_recipients) {
1027 return Err(SendError::BufferFull);
1030 match message_recipients.entry(*peer_node_id) {
1031 hash_map::Entry::Occupied(mut e) if e.get().is_connected() => {
1032 e.get_mut().enqueue_message(message);
1035 _ => Err(SendError::InvalidFirstHop(*peer_node_id))
1039 #[cfg(any(test, feature = "_test_utils"))]
1040 pub fn send_onion_message_using_path<T: OnionMessageContents>(
1041 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>
1042 ) -> Result<SendSuccess, SendError> {
1043 self.enqueue_onion_message(path, contents, reply_path, format_args!(""))
1046 pub(crate) fn peel_onion_message(
1047 &self, msg: &OnionMessage
1048 ) -> Result<PeeledOnion<<<CMH>::Target as CustomOnionMessageHandler>::CustomMessage>, ()> {
1050 msg, &self.secp_ctx, &*self.node_signer, &*self.logger, &*self.custom_handler
1054 fn handle_onion_message_response<T: OnionMessageContents>(
1055 &self, response: ResponseInstruction<T>
1057 if let ResponseInstruction::WithoutReplyPath(response) = response {
1058 let message_type = response.message.msg_type();
1059 let _ = self.find_path_and_enqueue_onion_message(
1060 response.message, Destination::BlindedPath(response.reply_path), None,
1062 "when responding with {} to an onion message with path_id {:02x?}",
1071 pub(super) fn release_pending_msgs(&self) -> HashMap<PublicKey, VecDeque<OnionMessage>> {
1072 let mut message_recipients = self.message_recipients.lock().unwrap();
1073 let mut msgs = new_hash_map();
1074 // We don't want to disconnect the peers by removing them entirely from the original map, so we
1075 // release the pending message buffers individually.
1076 for (node_id, recipient) in &mut *message_recipients {
1077 msgs.insert(*node_id, recipient.release_pending_messages());
1082 fn enqueue_event(&self, event: Event) {
1083 const MAX_EVENTS_BUFFER_SIZE: usize = (1 << 10) * 256;
1084 let mut pending_events = self.pending_events.lock().unwrap();
1085 let total_buffered_bytes: usize = pending_events
1087 .map(|ev| ev.serialized_length())
1089 if total_buffered_bytes >= MAX_EVENTS_BUFFER_SIZE {
1090 log_trace!(self.logger, "Dropping event {:?}: buffer full", event);
1093 pending_events.push(event);
1097 fn outbound_buffer_full(peer_node_id: &PublicKey, buffer: &HashMap<PublicKey, OnionMessageRecipient>) -> bool {
1098 const MAX_TOTAL_BUFFER_SIZE: usize = (1 << 20) * 128;
1099 const MAX_PER_PEER_BUFFER_SIZE: usize = (1 << 10) * 256;
1100 let mut total_buffered_bytes = 0;
1101 let mut peer_buffered_bytes = 0;
1102 for (pk, peer_buf) in buffer {
1103 for om in peer_buf.pending_messages() {
1104 let om_len = om.serialized_length();
1105 if pk == peer_node_id {
1106 peer_buffered_bytes += om_len;
1108 total_buffered_bytes += om_len;
1110 if total_buffered_bytes >= MAX_TOTAL_BUFFER_SIZE ||
1111 peer_buffered_bytes >= MAX_PER_PEER_BUFFER_SIZE
1120 impl<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, CMH: Deref> EventsProvider
1121 for OnionMessenger<ES, NS, L, NL, MR, OMH, CMH>
1123 ES::Target: EntropySource,
1124 NS::Target: NodeSigner,
1126 NL::Target: NodeIdLookUp,
1127 MR::Target: MessageRouter,
1128 OMH::Target: OffersMessageHandler,
1129 CMH::Target: CustomOnionMessageHandler,
1131 fn process_pending_events<H: Deref>(&self, handler: H) where H::Target: EventHandler {
1132 for (node_id, recipient) in self.message_recipients.lock().unwrap().iter_mut() {
1133 if let OnionMessageRecipient::PendingConnection(_, addresses, _) = recipient {
1134 if let Some(addresses) = addresses.take() {
1135 handler.handle_event(Event::ConnectionNeeded { node_id: *node_id, addresses });
1139 let mut events = Vec::new();
1140 core::mem::swap(&mut *self.pending_events.lock().unwrap(), &mut events);
1142 handler.handle_event(ev);
1147 impl<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, CMH: Deref> OnionMessageHandler
1148 for OnionMessenger<ES, NS, L, NL, MR, OMH, CMH>
1150 ES::Target: EntropySource,
1151 NS::Target: NodeSigner,
1153 NL::Target: NodeIdLookUp,
1154 MR::Target: MessageRouter,
1155 OMH::Target: OffersMessageHandler,
1156 CMH::Target: CustomOnionMessageHandler,
1158 fn handle_onion_message(&self, peer_node_id: &PublicKey, msg: &OnionMessage) {
1159 let logger = WithContext::from(&self.logger, Some(*peer_node_id), None, None);
1160 match self.peel_onion_message(msg) {
1161 Ok(PeeledOnion::Receive(message, path_id, reply_path)) => {
1164 "Received an onion message with path_id {:02x?} and {} reply_path: {:?}",
1165 path_id, if reply_path.is_some() { "a" } else { "no" }, message);
1168 ParsedOnionMessageContents::Offers(msg) => {
1169 let responder = reply_path.map(
1170 |reply_path| Responder::new(reply_path, path_id)
1172 let response_instructions = self.offers_handler.handle_message(msg, responder);
1173 self.handle_onion_message_response(response_instructions);
1175 ParsedOnionMessageContents::Custom(msg) => {
1176 let responder = reply_path.map(
1177 |reply_path| Responder::new(reply_path, path_id)
1179 let response_instructions = self.custom_handler.handle_custom_message(msg, responder);
1180 self.handle_onion_message_response(response_instructions);
1184 Ok(PeeledOnion::Forward(next_hop, onion_message)) => {
1185 let next_node_id = match next_hop {
1186 NextMessageHop::NodeId(pubkey) => pubkey,
1187 NextMessageHop::ShortChannelId(scid) => match self.node_id_lookup.next_node_id(scid) {
1188 Some(pubkey) => pubkey,
1190 log_trace!(self.logger, "Dropping forwarded onion messager: unable to resolve next hop using SCID {}", scid);
1196 let mut message_recipients = self.message_recipients.lock().unwrap();
1197 if outbound_buffer_full(&next_node_id, &message_recipients) {
1200 "Dropping forwarded onion message to peer {}: outbound buffer full",
1207 .entry(next_node_id)
1208 .or_insert_with(|| OnionMessageRecipient::ConnectedPeer(VecDeque::new()));
1210 match message_recipients.entry(next_node_id) {
1211 hash_map::Entry::Occupied(mut e) if matches!(
1212 e.get(), OnionMessageRecipient::ConnectedPeer(..)
1214 e.get_mut().enqueue_message(onion_message);
1215 log_trace!(logger, "Forwarding an onion message to peer {}", next_node_id);
1217 _ if self.intercept_messages_for_offline_peers => {
1219 Event::OnionMessageIntercepted {
1220 peer_node_id: next_node_id, message: onion_message
1227 "Dropping forwarded onion message to disconnected peer {}",
1234 log_error!(logger, "Failed to process onion message {:?}", e);
1239 fn peer_connected(&self, their_node_id: &PublicKey, init: &msgs::Init, _inbound: bool) -> Result<(), ()> {
1240 if init.features.supports_onion_messages() {
1241 self.message_recipients.lock().unwrap()
1242 .entry(*their_node_id)
1243 .or_insert_with(|| OnionMessageRecipient::ConnectedPeer(VecDeque::new()))
1245 if self.intercept_messages_for_offline_peers {
1247 Event::OnionMessagePeerConnected { peer_node_id: *their_node_id }
1251 self.message_recipients.lock().unwrap().remove(their_node_id);
1257 fn peer_disconnected(&self, their_node_id: &PublicKey) {
1258 match self.message_recipients.lock().unwrap().remove(their_node_id) {
1259 Some(OnionMessageRecipient::ConnectedPeer(..)) => {},
1260 Some(_) => debug_assert!(false),
1265 fn timer_tick_occurred(&self) {
1266 let mut message_recipients = self.message_recipients.lock().unwrap();
1268 // Drop any pending recipients since the last call to avoid retaining buffered messages for
1270 message_recipients.retain(|_, recipient| match recipient {
1271 OnionMessageRecipient::PendingConnection(_, None, ticks) => *ticks < MAX_TIMER_TICKS,
1272 OnionMessageRecipient::PendingConnection(_, Some(_), _) => true,
1276 // Increment a timer tick for pending recipients so that their buffered messages are dropped
1277 // at MAX_TIMER_TICKS.
1278 for recipient in message_recipients.values_mut() {
1279 if let OnionMessageRecipient::PendingConnection(_, None, ticks) = recipient {
1285 fn provided_node_features(&self) -> NodeFeatures {
1286 let mut features = NodeFeatures::empty();
1287 features.set_onion_messages_optional();
1291 fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
1292 let mut features = InitFeatures::empty();
1293 features.set_onion_messages_optional();
1297 // Before returning any messages to send for the peer, this method will see if any messages were
1298 // enqueued in the handler by users, find a path to the corresponding blinded path's introduction
1299 // node, and then enqueue the message for sending to the first peer in the full path.
1300 fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<OnionMessage> {
1301 // Enqueue any initiating `OffersMessage`s to send.
1302 for message in self.offers_handler.release_pending_messages() {
1303 #[cfg(not(c_bindings))]
1304 let PendingOnionMessage { contents, destination, reply_path } = message;
1306 let (contents, destination, reply_path) = message;
1307 let _ = self.find_path_and_enqueue_onion_message(
1308 contents, destination, reply_path, format_args!("when sending OffersMessage")
1312 // Enqueue any initiating `CustomMessage`s to send.
1313 for message in self.custom_handler.release_pending_custom_messages() {
1314 #[cfg(not(c_bindings))]
1315 let PendingOnionMessage { contents, destination, reply_path } = message;
1317 let (contents, destination, reply_path) = message;
1318 let _ = self.find_path_and_enqueue_onion_message(
1319 contents, destination, reply_path, format_args!("when sending CustomMessage")
1323 self.message_recipients.lock().unwrap()
1324 .get_mut(&peer_node_id)
1325 .and_then(|buffer| buffer.dequeue_message())
1329 // TODO: parameterize the below Simple* types with OnionMessenger and handle the messages it
1331 /// Useful for simplifying the parameters of [`SimpleArcChannelManager`] and
1332 /// [`SimpleArcPeerManager`]. See their docs for more details.
1334 /// This is not exported to bindings users as type aliases aren't supported in most languages.
1336 /// [`SimpleArcChannelManager`]: crate::ln::channelmanager::SimpleArcChannelManager
1337 /// [`SimpleArcPeerManager`]: crate::ln::peer_handler::SimpleArcPeerManager
1338 #[cfg(not(c_bindings))]
1339 pub type SimpleArcOnionMessenger<M, T, F, L> = OnionMessenger<
1343 Arc<SimpleArcChannelManager<M, T, F, L>>,
1344 Arc<DefaultMessageRouter<Arc<NetworkGraph<Arc<L>>>, Arc<L>, Arc<KeysManager>>>,
1345 Arc<SimpleArcChannelManager<M, T, F, L>>,
1346 IgnoringMessageHandler
1349 /// Useful for simplifying the parameters of [`SimpleRefChannelManager`] and
1350 /// [`SimpleRefPeerManager`]. See their docs for more details.
1352 /// This is not exported to bindings users as type aliases aren't supported in most languages.
1354 /// [`SimpleRefChannelManager`]: crate::ln::channelmanager::SimpleRefChannelManager
1355 /// [`SimpleRefPeerManager`]: crate::ln::peer_handler::SimpleRefPeerManager
1356 #[cfg(not(c_bindings))]
1357 pub type SimpleRefOnionMessenger<
1358 'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, 'i, 'j, M, T, F, L
1363 &'i SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, M, T, F, L>,
1364 &'j DefaultMessageRouter<&'g NetworkGraph<&'b L>, &'b L, &'a KeysManager>,
1365 &'i SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, M, T, F, L>,
1366 IgnoringMessageHandler
1369 /// Construct onion packet payloads and keys for sending an onion message along the given
1370 /// `unblinded_path` to the given `destination`.
1371 fn packet_payloads_and_keys<T: OnionMessageContents, S: secp256k1::Signing + secp256k1::Verification>(
1372 secp_ctx: &Secp256k1<S>, unblinded_path: &[PublicKey], destination: Destination, message: T,
1373 mut reply_path: Option<BlindedPath>, session_priv: &SecretKey
1374 ) -> Result<(Vec<(Payload<T>, [u8; 32])>, Vec<onion_utils::OnionKeys>), SendError> {
1375 let num_hops = unblinded_path.len() + destination.num_hops();
1376 let mut payloads = Vec::with_capacity(num_hops);
1377 let mut onion_packet_keys = Vec::with_capacity(num_hops);
1379 let (mut intro_node_id_blinding_pt, num_blinded_hops) = match &destination {
1380 Destination::Node(_) => (None, 0),
1381 Destination::BlindedPath(BlindedPath { introduction_node, blinding_point, blinded_hops }) => {
1382 let introduction_node_id = match introduction_node {
1383 IntroductionNode::NodeId(pubkey) => pubkey,
1384 IntroductionNode::DirectedShortChannelId(..) => {
1385 return Err(SendError::UnresolvedIntroductionNode);
1388 (Some((*introduction_node_id, *blinding_point)), blinded_hops.len())
1391 let num_unblinded_hops = num_hops - num_blinded_hops;
1393 let mut unblinded_path_idx = 0;
1394 let mut blinded_path_idx = 0;
1395 let mut prev_control_tlvs_ss = None;
1396 let mut final_control_tlvs = None;
1397 utils::construct_keys_callback(secp_ctx, unblinded_path.iter(), Some(destination), session_priv,
1398 |_, onion_packet_ss, ephemeral_pubkey, control_tlvs_ss, unblinded_pk_opt, enc_payload_opt| {
1399 if num_unblinded_hops != 0 && unblinded_path_idx < num_unblinded_hops {
1400 if let Some(ss) = prev_control_tlvs_ss.take() {
1401 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(
1403 next_hop: NextMessageHop::NodeId(unblinded_pk_opt.unwrap()),
1404 next_blinding_override: None,
1408 prev_control_tlvs_ss = Some(control_tlvs_ss);
1409 unblinded_path_idx += 1;
1410 } else if let Some((intro_node_id, blinding_pt)) = intro_node_id_blinding_pt.take() {
1411 if let Some(control_tlvs_ss) = prev_control_tlvs_ss.take() {
1412 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
1413 next_hop: NextMessageHop::NodeId(intro_node_id),
1414 next_blinding_override: Some(blinding_pt),
1415 })), control_tlvs_ss));
1418 if blinded_path_idx < num_blinded_hops.saturating_sub(1) && enc_payload_opt.is_some() {
1419 payloads.push((Payload::Forward(ForwardControlTlvs::Blinded(enc_payload_opt.unwrap())),
1421 blinded_path_idx += 1;
1422 } else if let Some(encrypted_payload) = enc_payload_opt {
1423 final_control_tlvs = Some(ReceiveControlTlvs::Blinded(encrypted_payload));
1424 prev_control_tlvs_ss = Some(control_tlvs_ss);
1427 let (rho, mu) = onion_utils::gen_rho_mu_from_shared_secret(onion_packet_ss.as_ref());
1428 onion_packet_keys.push(onion_utils::OnionKeys {
1430 shared_secret: onion_packet_ss,
1432 blinding_factor: [0; 32],
1438 ).map_err(|e| SendError::Secp256k1(e))?;
1440 if let Some(control_tlvs) = final_control_tlvs {
1441 payloads.push((Payload::Receive {
1443 reply_path: reply_path.take(),
1445 }, prev_control_tlvs_ss.unwrap()));
1447 payloads.push((Payload::Receive {
1448 control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id: None, }),
1449 reply_path: reply_path.take(),
1451 }, prev_control_tlvs_ss.unwrap()));
1454 Ok((payloads, onion_packet_keys))
1457 /// Errors if the serialized payload size exceeds onion_message::BIG_PACKET_HOP_DATA_LEN
1458 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, ()> {
1460 // "`len` allows larger messages to be sent than the standard 1300 bytes allowed for an HTLC
1461 // onion, but this should be used sparingly as it is reduces anonymity set, hence the
1462 // recommendation that it either look like an HTLC onion, or if larger, be a fixed size."
1463 let payloads_ser_len = onion_utils::payloads_serialized_length(&payloads);
1464 let hop_data_len = if payloads_ser_len <= SMALL_PACKET_HOP_DATA_LEN {
1465 SMALL_PACKET_HOP_DATA_LEN
1466 } else if payloads_ser_len <= BIG_PACKET_HOP_DATA_LEN {
1467 BIG_PACKET_HOP_DATA_LEN
1468 } else { return Err(()) };
1470 onion_utils::construct_onion_message_packet::<_, _>(
1471 payloads, onion_keys, prng_seed, hop_data_len)