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, 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::sign::{EntropySource, KeysManager};
75 /// # use lightning::ln::peer_handler::IgnoringMessageHandler;
76 /// # use lightning::onion_message::messenger::{Destination, MessageRouter, OnionMessagePath, OnionMessenger};
77 /// # use lightning::onion_message::packet::OnionMessageContents;
78 /// # use lightning::util::logger::{Logger, Record};
79 /// # use lightning::util::ser::{Writeable, Writer};
80 /// # use lightning::io;
81 /// # use std::sync::Arc;
82 /// # struct FakeLogger;
83 /// # impl Logger for FakeLogger {
84 /// # fn log(&self, record: Record) { println!("{:?}" , record); }
86 /// # struct FakeMessageRouter {}
87 /// # impl MessageRouter for FakeMessageRouter {
88 /// # fn find_path(&self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination) -> Result<OnionMessagePath, ()> {
89 /// # let secp_ctx = Secp256k1::new();
90 /// # let node_secret = SecretKey::from_slice(&<Vec<u8>>::from_hex("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
91 /// # let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
92 /// # let hop_node_id2 = hop_node_id1;
93 /// # Ok(OnionMessagePath {
94 /// # intermediate_nodes: vec![hop_node_id1, hop_node_id2],
96 /// # first_node_addresses: None,
99 /// # fn create_blinded_paths<T: secp256k1::Signing + secp256k1::Verification>(
100 /// # &self, _recipient: PublicKey, _peers: Vec<PublicKey>, _secp_ctx: &Secp256k1<T>
101 /// # ) -> Result<Vec<BlindedPath>, ()> {
105 /// # let seed = [42u8; 32];
106 /// # let time = Duration::from_secs(123456);
107 /// # let keys_manager = KeysManager::new(&seed, time.as_secs(), time.subsec_nanos());
108 /// # let logger = Arc::new(FakeLogger {});
109 /// # let node_secret = SecretKey::from_slice(&<Vec<u8>>::from_hex("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
110 /// # let secp_ctx = Secp256k1::new();
111 /// # let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
112 /// # let (hop_node_id3, hop_node_id4) = (hop_node_id1, hop_node_id1);
113 /// # let destination_node_id = hop_node_id1;
114 /// # let node_id_lookup = EmptyNodeIdLookUp {};
115 /// # let message_router = Arc::new(FakeMessageRouter {});
116 /// # let custom_message_handler = IgnoringMessageHandler {};
117 /// # let offers_message_handler = IgnoringMessageHandler {};
118 /// // Create the onion messenger. This must use the same `keys_manager` as is passed to your
119 /// // ChannelManager.
120 /// let onion_messenger = OnionMessenger::new(
121 /// &keys_manager, &keys_manager, logger, &node_id_lookup, message_router,
122 /// &offers_message_handler, &custom_message_handler
125 /// # #[derive(Debug)]
126 /// # struct YourCustomMessage {}
127 /// impl Writeable for YourCustomMessage {
128 /// fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
130 /// // Write your custom onion message to `w`
133 /// impl OnionMessageContents for YourCustomMessage {
134 /// fn tlv_type(&self) -> u64 {
135 /// # let your_custom_message_type = 42;
136 /// your_custom_message_type
138 /// fn msg_type(&self) -> &'static str { "YourCustomMessageType" }
140 /// // Send a custom onion message to a node id.
141 /// let destination = Destination::Node(destination_node_id);
142 /// let reply_path = None;
143 /// # let message = YourCustomMessage {};
144 /// onion_messenger.send_onion_message(message, destination, reply_path);
146 /// // Create a blinded path to yourself, for someone to send an onion message to.
147 /// # let your_node_id = hop_node_id1;
148 /// let hops = [hop_node_id3, hop_node_id4, your_node_id];
149 /// let blinded_path = BlindedPath::new_for_message(&hops, &keys_manager, &secp_ctx).unwrap();
151 /// // Send a custom onion message to a blinded path.
152 /// let destination = Destination::BlindedPath(blinded_path);
153 /// let reply_path = None;
154 /// # let message = YourCustomMessage {};
155 /// onion_messenger.send_onion_message(message, destination, reply_path);
158 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
159 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
160 pub struct OnionMessenger<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, CMH: Deref>
162 ES::Target: EntropySource,
163 NS::Target: NodeSigner,
165 NL::Target: NodeIdLookUp,
166 MR::Target: MessageRouter,
167 OMH::Target: OffersMessageHandler,
168 CMH::Target: CustomOnionMessageHandler,
173 message_recipients: Mutex<HashMap<PublicKey, OnionMessageRecipient>>,
174 secp_ctx: Secp256k1<secp256k1::All>,
179 intercept_messages_for_offline_peers: bool,
180 pending_events: Mutex<Vec<Event>>,
183 /// [`OnionMessage`]s buffered to be sent.
184 enum OnionMessageRecipient {
185 /// Messages for a node connected as a peer.
186 ConnectedPeer(VecDeque<OnionMessage>),
188 /// Messages for a node that is not yet connected, which are dropped after [`MAX_TIMER_TICKS`]
189 /// and tracked here.
190 PendingConnection(VecDeque<OnionMessage>, Option<Vec<SocketAddress>>, usize),
193 impl OnionMessageRecipient {
194 fn pending_connection(addresses: Vec<SocketAddress>) -> Self {
195 Self::PendingConnection(VecDeque::new(), Some(addresses), 0)
198 fn pending_messages(&self) -> &VecDeque<OnionMessage> {
200 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
201 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
205 fn enqueue_message(&mut self, message: OnionMessage) {
206 let pending_messages = match self {
207 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
208 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
211 pending_messages.push_back(message);
214 fn dequeue_message(&mut self) -> Option<OnionMessage> {
215 let pending_messages = match self {
216 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
217 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => {
218 debug_assert!(false);
223 pending_messages.pop_front()
227 fn release_pending_messages(&mut self) -> VecDeque<OnionMessage> {
228 let pending_messages = match self {
229 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
230 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
233 core::mem::take(pending_messages)
236 fn mark_connected(&mut self) {
237 if let OnionMessageRecipient::PendingConnection(pending_messages, _, _) = self {
238 let mut new_pending_messages = VecDeque::new();
239 core::mem::swap(pending_messages, &mut new_pending_messages);
240 *self = OnionMessageRecipient::ConnectedPeer(new_pending_messages);
244 fn is_connected(&self) -> bool {
246 OnionMessageRecipient::ConnectedPeer(..) => true,
247 OnionMessageRecipient::PendingConnection(..) => false,
253 /// The `Responder` struct creates an appropriate [`ResponseInstruction`]
254 /// for responding to a message.
255 pub struct Responder {
256 /// The path along which a response can be sent.
257 reply_path: BlindedPath,
258 path_id: Option<[u8; 32]>
262 /// Creates a new [`Responder`] instance with the provided reply path.
263 fn new(reply_path: BlindedPath, path_id: Option<[u8; 32]>) -> Self {
270 /// Creates the appropriate [`ResponseInstruction`] for a given response.
271 pub fn respond<T: OnionMessageContents>(self, response: T) -> ResponseInstruction<T> {
272 ResponseInstruction::WithoutReplyPath(OnionMessageResponse {
274 reply_path: self.reply_path,
275 path_id: self.path_id,
280 /// This struct contains the information needed to reply to a received message.
281 pub struct OnionMessageResponse<T: OnionMessageContents> {
283 reply_path: BlindedPath,
284 path_id: Option<[u8; 32]>,
287 /// `ResponseInstruction` represents instructions for responding to received messages.
288 pub enum ResponseInstruction<T: OnionMessageContents> {
289 /// Indicates that a response should be sent without including a reply path
290 /// for the recipient to respond back.
291 WithoutReplyPath(OnionMessageResponse<T>),
292 /// Indicates that there's no response to send back.
296 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
298 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
299 /// enqueued for sending.
300 #[cfg(not(c_bindings))]
301 pub struct PendingOnionMessage<T: OnionMessageContents> {
302 /// The message contents to send in an [`OnionMessage`].
305 /// The destination of the message.
306 pub destination: Destination,
308 /// A reply path to include in the [`OnionMessage`] for a response.
309 pub reply_path: Option<BlindedPath>,
313 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
315 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
316 /// enqueued for sending.
317 pub type PendingOnionMessage<T> = (T, Destination, Option<BlindedPath>);
319 pub(crate) fn new_pending_onion_message<T: OnionMessageContents>(
320 contents: T, destination: Destination, reply_path: Option<BlindedPath>
321 ) -> PendingOnionMessage<T> {
322 #[cfg(not(c_bindings))]
323 return PendingOnionMessage { contents, destination, reply_path };
325 return (contents, destination, reply_path);
328 /// A trait defining behavior for routing an [`OnionMessage`].
329 pub trait MessageRouter {
330 /// Returns a route for sending an [`OnionMessage`] to the given [`Destination`].
332 &self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
333 ) -> Result<OnionMessagePath, ()>;
335 /// Creates [`BlindedPath`]s to the `recipient` node. The nodes in `peers` are assumed to be
336 /// direct peers with the `recipient`.
337 fn create_blinded_paths<
338 T: secp256k1::Signing + secp256k1::Verification
340 &self, recipient: PublicKey, peers: Vec<PublicKey>, secp_ctx: &Secp256k1<T>,
341 ) -> Result<Vec<BlindedPath>, ()>;
344 /// A [`MessageRouter`] that can only route to a directly connected [`Destination`].
345 pub struct DefaultMessageRouter<G: Deref<Target=NetworkGraph<L>>, L: Deref, ES: Deref>
348 ES::Target: EntropySource,
354 impl<G: Deref<Target=NetworkGraph<L>>, L: Deref, ES: Deref> DefaultMessageRouter<G, L, ES>
357 ES::Target: EntropySource,
359 /// Creates a [`DefaultMessageRouter`] using the given [`NetworkGraph`].
360 pub fn new(network_graph: G, entropy_source: ES) -> Self {
361 Self { network_graph, entropy_source }
365 impl<G: Deref<Target=NetworkGraph<L>>, L: Deref, ES: Deref> MessageRouter for DefaultMessageRouter<G, L, ES>
368 ES::Target: EntropySource,
371 &self, sender: PublicKey, peers: Vec<PublicKey>, mut destination: Destination
372 ) -> Result<OnionMessagePath, ()> {
373 let network_graph = self.network_graph.deref().read_only();
374 destination.resolve(&network_graph);
376 let first_node = match destination.first_node() {
377 Some(first_node) => first_node,
378 None => return Err(()),
381 if peers.contains(&first_node) || sender == first_node {
382 Ok(OnionMessagePath {
383 intermediate_nodes: vec![], destination, first_node_addresses: None
386 let node_announcement = network_graph
387 .node(&NodeId::from_pubkey(&first_node))
388 .and_then(|node_info| node_info.announcement_info.as_ref())
389 .and_then(|announcement_info| announcement_info.announcement_message.as_ref())
390 .map(|node_announcement| &node_announcement.contents);
392 match node_announcement {
393 Some(node_announcement) if node_announcement.features.supports_onion_messages() => {
394 let first_node_addresses = Some(node_announcement.addresses.clone());
395 Ok(OnionMessagePath {
396 intermediate_nodes: vec![], destination, first_node_addresses
404 fn create_blinded_paths<
405 T: secp256k1::Signing + secp256k1::Verification
407 &self, recipient: PublicKey, peers: Vec<PublicKey>, secp_ctx: &Secp256k1<T>,
408 ) -> Result<Vec<BlindedPath>, ()> {
409 // Limit the number of blinded paths that are computed.
410 const MAX_PATHS: usize = 3;
412 // Ensure peers have at least three channels so that it is more difficult to infer the
413 // recipient's node_id.
414 const MIN_PEER_CHANNELS: usize = 3;
416 let network_graph = self.network_graph.deref().read_only();
417 let is_recipient_announced =
418 network_graph.nodes().contains_key(&NodeId::from_pubkey(&recipient));
420 let mut peer_info = peers.iter()
421 // Limit to peers with announced channels
424 .node(&NodeId::from_pubkey(pubkey))
425 .filter(|info| info.channels.len() >= MIN_PEER_CHANNELS)
426 .map(|info| (*pubkey, info.is_tor_only(), info.channels.len()))
428 // Exclude Tor-only nodes when the recipient is announced.
429 .filter(|(_, is_tor_only, _)| !(*is_tor_only && is_recipient_announced))
430 .collect::<Vec<_>>();
432 // Prefer using non-Tor nodes with the most channels as the introduction node.
433 peer_info.sort_unstable_by(|(_, a_tor_only, a_channels), (_, b_tor_only, b_channels)| {
434 a_tor_only.cmp(b_tor_only).then(a_channels.cmp(b_channels).reverse())
437 let paths = peer_info.into_iter()
438 .map(|(pubkey, _, _)| vec![pubkey, recipient])
439 .map(|node_pks| BlindedPath::new_for_message(&node_pks, &*self.entropy_source, secp_ctx))
441 .collect::<Result<Vec<_>, _>>();
444 Ok(paths) if !paths.is_empty() => Ok(paths),
446 if is_recipient_announced {
447 BlindedPath::one_hop_for_message(recipient, &*self.entropy_source, secp_ctx)
448 .map(|path| vec![path])
457 /// A path for sending an [`OnionMessage`].
459 pub struct OnionMessagePath {
460 /// Nodes on the path between the sender and the destination.
461 pub intermediate_nodes: Vec<PublicKey>,
463 /// The recipient of the message.
464 pub destination: Destination,
466 /// Addresses that may be used to connect to [`OnionMessagePath::first_node`].
468 /// Only needs to be set if a connection to the node is required. [`OnionMessenger`] may use
469 /// this to initiate such a connection.
470 pub first_node_addresses: Option<Vec<SocketAddress>>,
473 impl OnionMessagePath {
474 /// Returns the first node in the path.
475 pub fn first_node(&self) -> Option<PublicKey> {
476 self.intermediate_nodes
479 .or_else(|| self.destination.first_node())
483 /// The destination of an onion message.
484 #[derive(Clone, Hash, Debug, PartialEq, Eq)]
485 pub enum Destination {
486 /// We're sending this onion message to a node.
488 /// We're sending this onion message to a blinded path.
489 BlindedPath(BlindedPath),
493 /// Attempts to resolve the [`IntroductionNode::DirectedShortChannelId`] of a
494 /// [`Destination::BlindedPath`] to a [`IntroductionNode::NodeId`], if applicable, using the
495 /// provided [`ReadOnlyNetworkGraph`].
496 pub fn resolve(&mut self, network_graph: &ReadOnlyNetworkGraph) {
497 if let Destination::BlindedPath(path) = self {
498 if let IntroductionNode::DirectedShortChannelId(..) = path.introduction_node {
499 if let Some(pubkey) = path
500 .public_introduction_node_id(network_graph)
501 .and_then(|node_id| node_id.as_pubkey().ok())
503 path.introduction_node = IntroductionNode::NodeId(pubkey);
509 pub(super) fn num_hops(&self) -> usize {
511 Destination::Node(_) => 1,
512 Destination::BlindedPath(BlindedPath { blinded_hops, .. }) => blinded_hops.len(),
516 fn first_node(&self) -> Option<PublicKey> {
518 Destination::Node(node_id) => Some(*node_id),
519 Destination::BlindedPath(BlindedPath { introduction_node, .. }) => {
520 match introduction_node {
521 IntroductionNode::NodeId(pubkey) => Some(*pubkey),
522 IntroductionNode::DirectedShortChannelId(..) => None,
529 /// Result of successfully [sending an onion message].
531 /// [sending an onion message]: OnionMessenger::send_onion_message
532 #[derive(Clone, Hash, Debug, PartialEq, Eq)]
533 pub enum SendSuccess {
534 /// The message was buffered and will be sent once it is processed by
535 /// [`OnionMessageHandler::next_onion_message_for_peer`].
537 /// The message was buffered and will be sent once the node is connected as a peer and it is
538 /// processed by [`OnionMessageHandler::next_onion_message_for_peer`].
539 BufferedAwaitingConnection(PublicKey),
542 /// Errors that may occur when [sending an onion message].
544 /// [sending an onion message]: OnionMessenger::send_onion_message
545 #[derive(Clone, Hash, Debug, PartialEq, Eq)]
547 /// Errored computing onion message packet keys.
548 Secp256k1(secp256k1::Error),
549 /// Because implementations such as Eclair will drop onion messages where the message packet
550 /// exceeds 32834 bytes, we refuse to send messages where the packet exceeds this size.
552 /// The provided [`Destination`] was an invalid [`BlindedPath`] due to not having any blinded
555 /// The first hop is not a peer and doesn't have a known [`SocketAddress`].
556 InvalidFirstHop(PublicKey),
557 /// A path from the sender to the destination could not be found by the [`MessageRouter`].
559 /// Onion message contents must have a TLV type >= 64.
561 /// Our next-hop peer's buffer was full or our total outbound buffer was full.
563 /// Failed to retrieve our node id from the provided [`NodeSigner`].
565 /// [`NodeSigner`]: crate::sign::NodeSigner
567 /// The provided [`Destination`] has a blinded path with an unresolved introduction node. An
568 /// attempt to resolve it in the [`MessageRouter`] when finding an [`OnionMessagePath`] likely
570 UnresolvedIntroductionNode,
571 /// We attempted to send to a blinded path where we are the introduction node, and failed to
572 /// advance the blinded path to make the second hop the new introduction node. Either
573 /// [`NodeSigner::ecdh`] failed, we failed to tweak the current blinding point to get the
574 /// new blinding point, or we were attempting to send to ourselves.
575 BlindedPathAdvanceFailed,
578 /// Handler for custom onion messages. If you are using [`SimpleArcOnionMessenger`],
579 /// [`SimpleRefOnionMessenger`], or prefer to ignore inbound custom onion messages,
580 /// [`IgnoringMessageHandler`] must be provided to [`OnionMessenger::new`]. Otherwise, a custom
581 /// implementation of this trait must be provided, with [`CustomMessage`] specifying the supported
584 /// See [`OnionMessenger`] for example usage.
586 /// [`IgnoringMessageHandler`]: crate::ln::peer_handler::IgnoringMessageHandler
587 /// [`CustomMessage`]: Self::CustomMessage
588 pub trait CustomOnionMessageHandler {
589 /// The message known to the handler. To support multiple message types, you may want to make this
590 /// an enum with a variant for each supported message.
591 type CustomMessage: OnionMessageContents;
593 /// Called with the custom message that was received, returning a response to send, if any.
595 /// The returned [`Self::CustomMessage`], if any, is enqueued to be sent by [`OnionMessenger`].
596 fn handle_custom_message(&self, message: Self::CustomMessage, responder: Option<Responder>) -> ResponseInstruction<Self::CustomMessage>;
598 /// Read a custom message of type `message_type` from `buffer`, returning `Ok(None)` if the
599 /// message type is unknown.
600 fn read_custom_message<R: io::Read>(&self, message_type: u64, buffer: &mut R) -> Result<Option<Self::CustomMessage>, msgs::DecodeError>;
602 /// Releases any [`Self::CustomMessage`]s that need to be sent.
604 /// Typically, this is used for messages initiating a message flow rather than in response to
605 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
606 #[cfg(not(c_bindings))]
607 fn release_pending_custom_messages(&self) -> Vec<PendingOnionMessage<Self::CustomMessage>>;
609 /// Releases any [`Self::CustomMessage`]s that need to be sent.
611 /// Typically, this is used for messages initiating a message flow rather than in response to
612 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
614 fn release_pending_custom_messages(&self) -> Vec<(Self::CustomMessage, Destination, Option<BlindedPath>)>;
617 /// A processed incoming onion message, containing either a Forward (another onion message)
618 /// or a Receive payload with decrypted contents.
619 #[derive(Clone, Debug)]
620 pub enum PeeledOnion<T: OnionMessageContents> {
621 /// Forwarded onion, with the next node id and a new onion
622 Forward(NextMessageHop, OnionMessage),
623 /// Received onion message, with decrypted contents, path_id, and reply path
624 Receive(ParsedOnionMessageContents<T>, Option<[u8; 32]>, Option<BlindedPath>)
628 /// Creates an [`OnionMessage`] with the given `contents` for sending to the destination of
629 /// `path`, first calling [`Destination::resolve`] on `path.destination` with the given
630 /// [`ReadOnlyNetworkGraph`].
632 /// Returns the node id of the peer to send the message to, the message itself, and any addresses
633 /// needed to connect to the first node.
634 pub fn create_onion_message_resolving_destination<
635 ES: Deref, NS: Deref, NL: Deref, T: OnionMessageContents
637 entropy_source: &ES, node_signer: &NS, node_id_lookup: &NL,
638 network_graph: &ReadOnlyNetworkGraph, secp_ctx: &Secp256k1<secp256k1::All>,
639 mut path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
640 ) -> Result<(PublicKey, OnionMessage, Option<Vec<SocketAddress>>), SendError>
642 ES::Target: EntropySource,
643 NS::Target: NodeSigner,
644 NL::Target: NodeIdLookUp,
646 path.destination.resolve(network_graph);
647 create_onion_message(
648 entropy_source, node_signer, node_id_lookup, secp_ctx, path, contents, reply_path,
652 /// Creates an [`OnionMessage`] with the given `contents` for sending to the destination of
655 /// Returns the node id of the peer to send the message to, the message itself, and any addresses
656 /// needed to connect to the first node.
658 /// Returns [`SendError::UnresolvedIntroductionNode`] if:
659 /// - `destination` contains a blinded path with an [`IntroductionNode::DirectedShortChannelId`],
660 /// - unless it can be resolved by [`NodeIdLookUp::next_node_id`].
661 /// Use [`create_onion_message_resolving_destination`] instead to resolve the introduction node
662 /// first with a [`ReadOnlyNetworkGraph`].
663 pub fn create_onion_message<ES: Deref, NS: Deref, NL: Deref, T: OnionMessageContents>(
664 entropy_source: &ES, node_signer: &NS, node_id_lookup: &NL,
665 secp_ctx: &Secp256k1<secp256k1::All>, path: OnionMessagePath, contents: T,
666 reply_path: Option<BlindedPath>,
667 ) -> Result<(PublicKey, OnionMessage, Option<Vec<SocketAddress>>), SendError>
669 ES::Target: EntropySource,
670 NS::Target: NodeSigner,
671 NL::Target: NodeIdLookUp,
673 let OnionMessagePath { intermediate_nodes, mut destination, first_node_addresses } = path;
674 if let Destination::BlindedPath(BlindedPath { ref blinded_hops, .. }) = destination {
675 if blinded_hops.is_empty() {
676 return Err(SendError::TooFewBlindedHops);
680 if contents.tlv_type() < 64 { return Err(SendError::InvalidMessage) }
682 // If we are sending straight to a blinded path and we are the introduction node, we need to
683 // advance the blinded path by 1 hop so the second hop is the new introduction node.
684 if intermediate_nodes.len() == 0 {
685 if let Destination::BlindedPath(ref mut blinded_path) = destination {
686 let our_node_id = node_signer.get_node_id(Recipient::Node)
687 .map_err(|()| SendError::GetNodeIdFailed)?;
688 let introduction_node_id = match blinded_path.introduction_node {
689 IntroductionNode::NodeId(pubkey) => pubkey,
690 IntroductionNode::DirectedShortChannelId(direction, scid) => {
691 match node_id_lookup.next_node_id(scid) {
692 Some(next_node_id) => *direction.select_pubkey(&our_node_id, &next_node_id),
693 None => return Err(SendError::UnresolvedIntroductionNode),
697 if introduction_node_id == our_node_id {
698 advance_path_by_one(blinded_path, node_signer, node_id_lookup, &secp_ctx)
699 .map_err(|()| SendError::BlindedPathAdvanceFailed)?;
704 let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
705 let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
706 let (first_node_id, blinding_point) = if let Some(first_node_id) = intermediate_nodes.first() {
707 (*first_node_id, PublicKey::from_secret_key(&secp_ctx, &blinding_secret))
710 Destination::Node(pk) => (*pk, PublicKey::from_secret_key(&secp_ctx, &blinding_secret)),
711 Destination::BlindedPath(BlindedPath { introduction_node, blinding_point, .. }) => {
712 match introduction_node {
713 IntroductionNode::NodeId(pubkey) => (*pubkey, *blinding_point),
714 IntroductionNode::DirectedShortChannelId(..) => {
715 return Err(SendError::UnresolvedIntroductionNode);
721 let (packet_payloads, packet_keys) = packet_payloads_and_keys(
722 &secp_ctx, &intermediate_nodes, destination, contents, reply_path, &blinding_secret
725 let prng_seed = entropy_source.get_secure_random_bytes();
726 let onion_routing_packet = construct_onion_message_packet(
727 packet_payloads, packet_keys, prng_seed).map_err(|()| SendError::TooBigPacket)?;
729 let message = OnionMessage { blinding_point, onion_routing_packet };
730 Ok((first_node_id, message, first_node_addresses))
733 /// Decode one layer of an incoming [`OnionMessage`].
735 /// Returns either the next layer of the onion for forwarding or the decrypted content for the
737 pub fn peel_onion_message<NS: Deref, L: Deref, CMH: Deref>(
738 msg: &OnionMessage, secp_ctx: &Secp256k1<secp256k1::All>, node_signer: NS, logger: L,
740 ) -> Result<PeeledOnion<<<CMH>::Target as CustomOnionMessageHandler>::CustomMessage>, ()>
742 NS::Target: NodeSigner,
744 CMH::Target: CustomOnionMessageHandler,
746 let control_tlvs_ss = match node_signer.ecdh(Recipient::Node, &msg.blinding_point, None) {
749 log_error!(logger, "Failed to retrieve node secret: {:?}", e);
753 let onion_decode_ss = {
754 let blinding_factor = {
755 let mut hmac = HmacEngine::<Sha256>::new(b"blinded_node_id");
756 hmac.input(control_tlvs_ss.as_ref());
757 Hmac::from_engine(hmac).to_byte_array()
759 match node_signer.ecdh(Recipient::Node, &msg.onion_routing_packet.public_key,
760 Some(&Scalar::from_be_bytes(blinding_factor).unwrap()))
762 Ok(ss) => ss.secret_bytes(),
764 log_trace!(logger, "Failed to compute onion packet shared secret");
769 match onion_utils::decode_next_untagged_hop(
770 onion_decode_ss, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
771 (control_tlvs_ss, custom_handler.deref(), logger.deref())
773 Ok((Payload::Receive::<ParsedOnionMessageContents<<<CMH as Deref>::Target as CustomOnionMessageHandler>::CustomMessage>> {
774 message, control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id }), reply_path,
776 Ok(PeeledOnion::Receive(message, path_id, reply_path))
778 Ok((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
779 next_hop, next_blinding_override
780 })), Some((next_hop_hmac, new_packet_bytes)))) => {
781 // TODO: we need to check whether `next_hop` is our node, in which case this is a dummy
782 // blinded hop and this onion message is destined for us. In this situation, we should keep
783 // unwrapping the onion layers to get to the final payload. Since we don't have the option
784 // of creating blinded paths with dummy hops currently, we should be ok to not handle this
786 let new_pubkey = match onion_utils::next_hop_pubkey(&secp_ctx, msg.onion_routing_packet.public_key, &onion_decode_ss) {
789 log_trace!(logger, "Failed to compute next hop packet pubkey: {}", e);
793 let outgoing_packet = Packet {
795 public_key: new_pubkey,
796 hop_data: new_packet_bytes,
799 let onion_message = OnionMessage {
800 blinding_point: match next_blinding_override {
801 Some(blinding_point) => blinding_point,
803 match onion_utils::next_hop_pubkey(
804 &secp_ctx, msg.blinding_point, control_tlvs_ss.as_ref()
808 log_trace!(logger, "Failed to compute next blinding point: {}", e);
814 onion_routing_packet: outgoing_packet,
817 Ok(PeeledOnion::Forward(next_hop, onion_message))
820 log_trace!(logger, "Errored decoding onion message packet: {:?}", e);
824 log_trace!(logger, "Received bogus onion message packet, either the sender encoded a final hop as a forwarding hop or vice versa");
830 impl<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, CMH: Deref>
831 OnionMessenger<ES, NS, L, NL, MR, OMH, CMH>
833 ES::Target: EntropySource,
834 NS::Target: NodeSigner,
836 NL::Target: NodeIdLookUp,
837 MR::Target: MessageRouter,
838 OMH::Target: OffersMessageHandler,
839 CMH::Target: CustomOnionMessageHandler,
841 /// Constructs a new `OnionMessenger` to send, forward, and delegate received onion messages to
842 /// their respective handlers.
844 entropy_source: ES, node_signer: NS, logger: L, node_id_lookup: NL, message_router: MR,
845 offers_handler: OMH, custom_handler: CMH
848 entropy_source, node_signer, logger, node_id_lookup, message_router,
849 offers_handler, custom_handler, false
853 /// Similar to [`Self::new`], but rather than dropping onion messages that are
854 /// intended to be forwarded to offline peers, we will intercept them for
855 /// later forwarding.
857 /// Interception flow:
858 /// 1. If an onion message for an offline peer is received, `OnionMessenger` will
859 /// generate an [`Event::OnionMessageIntercepted`]. Event handlers can
860 /// then choose to persist this onion message for later forwarding, or drop
862 /// 2. When the offline peer later comes back online, `OnionMessenger` will
863 /// generate an [`Event::OnionMessagePeerConnected`]. Event handlers will
864 /// then fetch all previously intercepted onion messages for this peer.
865 /// 3. Once the stored onion messages are fetched, they can finally be
866 /// forwarded to the now-online peer via [`Self::forward_onion_message`].
870 /// LDK will not rate limit how many [`Event::OnionMessageIntercepted`]s
871 /// are generated, so it is the caller's responsibility to limit how many
872 /// onion messages are persisted and only persist onion messages for relevant
874 pub fn new_with_offline_peer_interception(
875 entropy_source: ES, node_signer: NS, logger: L, node_id_lookup: NL,
876 message_router: MR, offers_handler: OMH, custom_handler: CMH
879 entropy_source, node_signer, logger, node_id_lookup, message_router,
880 offers_handler, custom_handler, true
885 entropy_source: ES, node_signer: NS, logger: L, node_id_lookup: NL,
886 message_router: MR, offers_handler: OMH, custom_handler: CMH,
887 intercept_messages_for_offline_peers: bool
889 let mut secp_ctx = Secp256k1::new();
890 secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
894 message_recipients: Mutex::new(new_hash_map()),
901 intercept_messages_for_offline_peers,
902 pending_events: Mutex::new(Vec::new()),
907 pub(crate) fn set_offers_handler(&mut self, offers_handler: OMH) {
908 self.offers_handler = offers_handler;
911 /// Sends an [`OnionMessage`] with the given `contents` to `destination`.
913 /// See [`OnionMessenger`] for example usage.
914 pub fn send_onion_message<T: OnionMessageContents>(
915 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>
916 ) -> Result<SendSuccess, SendError> {
917 self.find_path_and_enqueue_onion_message(
918 contents, destination, reply_path, format_args!("")
922 fn find_path_and_enqueue_onion_message<T: OnionMessageContents>(
923 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>,
924 log_suffix: fmt::Arguments
925 ) -> Result<SendSuccess, SendError> {
926 let mut logger = WithContext::from(&self.logger, None, None);
927 let result = self.find_path(destination)
929 let first_hop = path.intermediate_nodes.get(0).map(|p| *p);
930 logger = WithContext::from(&self.logger, first_hop, None);
931 self.enqueue_onion_message(path, contents, reply_path, log_suffix)
934 match result.as_ref() {
935 Err(SendError::GetNodeIdFailed) => {
936 log_warn!(logger, "Unable to retrieve node id {}", log_suffix);
938 Err(SendError::PathNotFound) => {
939 log_trace!(logger, "Failed to find path {}", log_suffix);
942 log_trace!(logger, "Failed sending onion message {}: {:?}", log_suffix, e);
944 Ok(SendSuccess::Buffered) => {
945 log_trace!(logger, "Buffered onion message {}", log_suffix);
947 Ok(SendSuccess::BufferedAwaitingConnection(node_id)) => {
950 "Buffered onion message waiting on peer connection {}: {}",
959 fn find_path(&self, destination: Destination) -> Result<OnionMessagePath, SendError> {
960 let sender = self.node_signer
961 .get_node_id(Recipient::Node)
962 .map_err(|_| SendError::GetNodeIdFailed)?;
964 let peers = self.message_recipients.lock().unwrap()
966 .filter(|(_, recipient)| matches!(recipient, OnionMessageRecipient::ConnectedPeer(_)))
967 .map(|(node_id, _)| *node_id)
971 .find_path(sender, peers, destination)
972 .map_err(|_| SendError::PathNotFound)
975 fn enqueue_onion_message<T: OnionMessageContents>(
976 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
977 log_suffix: fmt::Arguments
978 ) -> Result<SendSuccess, SendError> {
979 log_trace!(self.logger, "Constructing onion message {}: {:?}", log_suffix, contents);
981 let (first_node_id, onion_message, addresses) = create_onion_message(
982 &self.entropy_source, &self.node_signer, &self.node_id_lookup, &self.secp_ctx, path,
983 contents, reply_path,
986 let mut message_recipients = self.message_recipients.lock().unwrap();
987 if outbound_buffer_full(&first_node_id, &message_recipients) {
988 return Err(SendError::BufferFull);
991 match message_recipients.entry(first_node_id) {
992 hash_map::Entry::Vacant(e) => match addresses {
993 None => Err(SendError::InvalidFirstHop(first_node_id)),
995 e.insert(OnionMessageRecipient::pending_connection(addresses))
996 .enqueue_message(onion_message);
997 Ok(SendSuccess::BufferedAwaitingConnection(first_node_id))
1000 hash_map::Entry::Occupied(mut e) => {
1001 e.get_mut().enqueue_message(onion_message);
1002 if e.get().is_connected() {
1003 Ok(SendSuccess::Buffered)
1005 Ok(SendSuccess::BufferedAwaitingConnection(first_node_id))
1011 /// Forwards an [`OnionMessage`] to `peer_node_id`. Useful if we initialized
1012 /// the [`OnionMessenger`] with [`Self::new_with_offline_peer_interception`]
1013 /// and want to forward a previously intercepted onion message to a peer that
1014 /// has just come online.
1015 pub fn forward_onion_message(
1016 &self, message: OnionMessage, peer_node_id: &PublicKey
1017 ) -> Result<(), SendError> {
1018 let mut message_recipients = self.message_recipients.lock().unwrap();
1019 if outbound_buffer_full(&peer_node_id, &message_recipients) {
1020 return Err(SendError::BufferFull);
1023 match message_recipients.entry(*peer_node_id) {
1024 hash_map::Entry::Occupied(mut e) if e.get().is_connected() => {
1025 e.get_mut().enqueue_message(message);
1028 _ => Err(SendError::InvalidFirstHop(*peer_node_id))
1032 #[cfg(any(test, feature = "_test_utils"))]
1033 pub fn send_onion_message_using_path<T: OnionMessageContents>(
1034 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>
1035 ) -> Result<SendSuccess, SendError> {
1036 self.enqueue_onion_message(path, contents, reply_path, format_args!(""))
1039 pub(crate) fn peel_onion_message(
1040 &self, msg: &OnionMessage
1041 ) -> Result<PeeledOnion<<<CMH>::Target as CustomOnionMessageHandler>::CustomMessage>, ()> {
1043 msg, &self.secp_ctx, &*self.node_signer, &*self.logger, &*self.custom_handler
1047 fn handle_onion_message_response<T: OnionMessageContents>(
1048 &self, response: ResponseInstruction<T>
1050 if let ResponseInstruction::WithoutReplyPath(response) = response {
1051 let message_type = response.message.msg_type();
1052 let _ = self.find_path_and_enqueue_onion_message(
1053 response.message, Destination::BlindedPath(response.reply_path), None,
1055 "when responding with {} to an onion message with path_id {:02x?}",
1064 pub(super) fn release_pending_msgs(&self) -> HashMap<PublicKey, VecDeque<OnionMessage>> {
1065 let mut message_recipients = self.message_recipients.lock().unwrap();
1066 let mut msgs = new_hash_map();
1067 // We don't want to disconnect the peers by removing them entirely from the original map, so we
1068 // release the pending message buffers individually.
1069 for (node_id, recipient) in &mut *message_recipients {
1070 msgs.insert(*node_id, recipient.release_pending_messages());
1075 fn enqueue_event(&self, event: Event) {
1076 const MAX_EVENTS_BUFFER_SIZE: usize = (1 << 10) * 256;
1077 let mut pending_events = self.pending_events.lock().unwrap();
1078 let total_buffered_bytes: usize = pending_events
1080 .map(|ev| ev.serialized_length())
1082 if total_buffered_bytes >= MAX_EVENTS_BUFFER_SIZE {
1083 log_trace!(self.logger, "Dropping event {:?}: buffer full", event);
1086 pending_events.push(event);
1090 fn outbound_buffer_full(peer_node_id: &PublicKey, buffer: &HashMap<PublicKey, OnionMessageRecipient>) -> bool {
1091 const MAX_TOTAL_BUFFER_SIZE: usize = (1 << 20) * 128;
1092 const MAX_PER_PEER_BUFFER_SIZE: usize = (1 << 10) * 256;
1093 let mut total_buffered_bytes = 0;
1094 let mut peer_buffered_bytes = 0;
1095 for (pk, peer_buf) in buffer {
1096 for om in peer_buf.pending_messages() {
1097 let om_len = om.serialized_length();
1098 if pk == peer_node_id {
1099 peer_buffered_bytes += om_len;
1101 total_buffered_bytes += om_len;
1103 if total_buffered_bytes >= MAX_TOTAL_BUFFER_SIZE ||
1104 peer_buffered_bytes >= MAX_PER_PEER_BUFFER_SIZE
1113 impl<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, CMH: Deref> EventsProvider
1114 for OnionMessenger<ES, NS, L, NL, MR, OMH, CMH>
1116 ES::Target: EntropySource,
1117 NS::Target: NodeSigner,
1119 NL::Target: NodeIdLookUp,
1120 MR::Target: MessageRouter,
1121 OMH::Target: OffersMessageHandler,
1122 CMH::Target: CustomOnionMessageHandler,
1124 fn process_pending_events<H: Deref>(&self, handler: H) where H::Target: EventHandler {
1125 for (node_id, recipient) in self.message_recipients.lock().unwrap().iter_mut() {
1126 if let OnionMessageRecipient::PendingConnection(_, addresses, _) = recipient {
1127 if let Some(addresses) = addresses.take() {
1128 handler.handle_event(Event::ConnectionNeeded { node_id: *node_id, addresses });
1132 let mut events = Vec::new();
1133 core::mem::swap(&mut *self.pending_events.lock().unwrap(), &mut events);
1135 handler.handle_event(ev);
1140 impl<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, CMH: Deref> OnionMessageHandler
1141 for OnionMessenger<ES, NS, L, NL, MR, OMH, CMH>
1143 ES::Target: EntropySource,
1144 NS::Target: NodeSigner,
1146 NL::Target: NodeIdLookUp,
1147 MR::Target: MessageRouter,
1148 OMH::Target: OffersMessageHandler,
1149 CMH::Target: CustomOnionMessageHandler,
1151 fn handle_onion_message(&self, peer_node_id: &PublicKey, msg: &OnionMessage) {
1152 let logger = WithContext::from(&self.logger, Some(*peer_node_id), None);
1153 match self.peel_onion_message(msg) {
1154 Ok(PeeledOnion::Receive(message, path_id, reply_path)) => {
1157 "Received an onion message with path_id {:02x?} and {} reply_path: {:?}",
1158 path_id, if reply_path.is_some() { "a" } else { "no" }, message);
1161 ParsedOnionMessageContents::Offers(msg) => {
1162 let responder = reply_path.map(
1163 |reply_path| Responder::new(reply_path, path_id)
1165 let response_instructions = self.offers_handler.handle_message(msg, responder);
1166 self.handle_onion_message_response(response_instructions);
1168 ParsedOnionMessageContents::Custom(msg) => {
1169 let responder = reply_path.map(
1170 |reply_path| Responder::new(reply_path, path_id)
1172 let response_instructions = self.custom_handler.handle_custom_message(msg, responder);
1173 self.handle_onion_message_response(response_instructions);
1177 Ok(PeeledOnion::Forward(next_hop, onion_message)) => {
1178 let next_node_id = match next_hop {
1179 NextMessageHop::NodeId(pubkey) => pubkey,
1180 NextMessageHop::ShortChannelId(scid) => match self.node_id_lookup.next_node_id(scid) {
1181 Some(pubkey) => pubkey,
1183 log_trace!(self.logger, "Dropping forwarded onion messager: unable to resolve next hop using SCID {}", scid);
1189 let mut message_recipients = self.message_recipients.lock().unwrap();
1190 if outbound_buffer_full(&next_node_id, &message_recipients) {
1193 "Dropping forwarded onion message to peer {}: outbound buffer full",
1200 .entry(next_node_id)
1201 .or_insert_with(|| OnionMessageRecipient::ConnectedPeer(VecDeque::new()));
1203 match message_recipients.entry(next_node_id) {
1204 hash_map::Entry::Occupied(mut e) if matches!(
1205 e.get(), OnionMessageRecipient::ConnectedPeer(..)
1207 e.get_mut().enqueue_message(onion_message);
1208 log_trace!(logger, "Forwarding an onion message to peer {}", next_node_id);
1210 _ if self.intercept_messages_for_offline_peers => {
1212 Event::OnionMessageIntercepted {
1213 peer_node_id: next_node_id, message: onion_message
1220 "Dropping forwarded onion message to disconnected peer {}",
1227 log_error!(logger, "Failed to process onion message {:?}", e);
1232 fn peer_connected(&self, their_node_id: &PublicKey, init: &msgs::Init, _inbound: bool) -> Result<(), ()> {
1233 if init.features.supports_onion_messages() {
1234 self.message_recipients.lock().unwrap()
1235 .entry(*their_node_id)
1236 .or_insert_with(|| OnionMessageRecipient::ConnectedPeer(VecDeque::new()))
1238 if self.intercept_messages_for_offline_peers {
1240 Event::OnionMessagePeerConnected { peer_node_id: *their_node_id }
1244 self.message_recipients.lock().unwrap().remove(their_node_id);
1250 fn peer_disconnected(&self, their_node_id: &PublicKey) {
1251 match self.message_recipients.lock().unwrap().remove(their_node_id) {
1252 Some(OnionMessageRecipient::ConnectedPeer(..)) => {},
1253 Some(_) => debug_assert!(false),
1258 fn timer_tick_occurred(&self) {
1259 let mut message_recipients = self.message_recipients.lock().unwrap();
1261 // Drop any pending recipients since the last call to avoid retaining buffered messages for
1263 message_recipients.retain(|_, recipient| match recipient {
1264 OnionMessageRecipient::PendingConnection(_, None, ticks) => *ticks < MAX_TIMER_TICKS,
1265 OnionMessageRecipient::PendingConnection(_, Some(_), _) => true,
1269 // Increment a timer tick for pending recipients so that their buffered messages are dropped
1270 // at MAX_TIMER_TICKS.
1271 for recipient in message_recipients.values_mut() {
1272 if let OnionMessageRecipient::PendingConnection(_, None, ticks) = recipient {
1278 fn provided_node_features(&self) -> NodeFeatures {
1279 let mut features = NodeFeatures::empty();
1280 features.set_onion_messages_optional();
1284 fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
1285 let mut features = InitFeatures::empty();
1286 features.set_onion_messages_optional();
1290 // Before returning any messages to send for the peer, this method will see if any messages were
1291 // enqueued in the handler by users, find a path to the corresponding blinded path's introduction
1292 // node, and then enqueue the message for sending to the first peer in the full path.
1293 fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<OnionMessage> {
1294 // Enqueue any initiating `OffersMessage`s to send.
1295 for message in self.offers_handler.release_pending_messages() {
1296 #[cfg(not(c_bindings))]
1297 let PendingOnionMessage { contents, destination, reply_path } = message;
1299 let (contents, destination, reply_path) = message;
1300 let _ = self.find_path_and_enqueue_onion_message(
1301 contents, destination, reply_path, format_args!("when sending OffersMessage")
1305 // Enqueue any initiating `CustomMessage`s to send.
1306 for message in self.custom_handler.release_pending_custom_messages() {
1307 #[cfg(not(c_bindings))]
1308 let PendingOnionMessage { contents, destination, reply_path } = message;
1310 let (contents, destination, reply_path) = message;
1311 let _ = self.find_path_and_enqueue_onion_message(
1312 contents, destination, reply_path, format_args!("when sending CustomMessage")
1316 self.message_recipients.lock().unwrap()
1317 .get_mut(&peer_node_id)
1318 .and_then(|buffer| buffer.dequeue_message())
1322 // TODO: parameterize the below Simple* types with OnionMessenger and handle the messages it
1324 /// Useful for simplifying the parameters of [`SimpleArcChannelManager`] and
1325 /// [`SimpleArcPeerManager`]. See their docs for more details.
1327 /// This is not exported to bindings users as type aliases aren't supported in most languages.
1329 /// [`SimpleArcChannelManager`]: crate::ln::channelmanager::SimpleArcChannelManager
1330 /// [`SimpleArcPeerManager`]: crate::ln::peer_handler::SimpleArcPeerManager
1331 #[cfg(not(c_bindings))]
1332 pub type SimpleArcOnionMessenger<M, T, F, L> = OnionMessenger<
1336 Arc<SimpleArcChannelManager<M, T, F, L>>,
1337 Arc<DefaultMessageRouter<Arc<NetworkGraph<Arc<L>>>, Arc<L>, Arc<KeysManager>>>,
1338 Arc<SimpleArcChannelManager<M, T, F, L>>,
1339 IgnoringMessageHandler
1342 /// Useful for simplifying the parameters of [`SimpleRefChannelManager`] and
1343 /// [`SimpleRefPeerManager`]. See their docs for more details.
1345 /// This is not exported to bindings users as type aliases aren't supported in most languages.
1347 /// [`SimpleRefChannelManager`]: crate::ln::channelmanager::SimpleRefChannelManager
1348 /// [`SimpleRefPeerManager`]: crate::ln::peer_handler::SimpleRefPeerManager
1349 #[cfg(not(c_bindings))]
1350 pub type SimpleRefOnionMessenger<
1351 'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, 'i, 'j, M, T, F, L
1356 &'i SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, M, T, F, L>,
1357 &'j DefaultMessageRouter<&'g NetworkGraph<&'b L>, &'b L, &'a KeysManager>,
1358 &'i SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, M, T, F, L>,
1359 IgnoringMessageHandler
1362 /// Construct onion packet payloads and keys for sending an onion message along the given
1363 /// `unblinded_path` to the given `destination`.
1364 fn packet_payloads_and_keys<T: OnionMessageContents, S: secp256k1::Signing + secp256k1::Verification>(
1365 secp_ctx: &Secp256k1<S>, unblinded_path: &[PublicKey], destination: Destination, message: T,
1366 mut reply_path: Option<BlindedPath>, session_priv: &SecretKey
1367 ) -> Result<(Vec<(Payload<T>, [u8; 32])>, Vec<onion_utils::OnionKeys>), SendError> {
1368 let num_hops = unblinded_path.len() + destination.num_hops();
1369 let mut payloads = Vec::with_capacity(num_hops);
1370 let mut onion_packet_keys = Vec::with_capacity(num_hops);
1372 let (mut intro_node_id_blinding_pt, num_blinded_hops) = match &destination {
1373 Destination::Node(_) => (None, 0),
1374 Destination::BlindedPath(BlindedPath { introduction_node, blinding_point, blinded_hops }) => {
1375 let introduction_node_id = match introduction_node {
1376 IntroductionNode::NodeId(pubkey) => pubkey,
1377 IntroductionNode::DirectedShortChannelId(..) => {
1378 return Err(SendError::UnresolvedIntroductionNode);
1381 (Some((*introduction_node_id, *blinding_point)), blinded_hops.len())
1384 let num_unblinded_hops = num_hops - num_blinded_hops;
1386 let mut unblinded_path_idx = 0;
1387 let mut blinded_path_idx = 0;
1388 let mut prev_control_tlvs_ss = None;
1389 let mut final_control_tlvs = None;
1390 utils::construct_keys_callback(secp_ctx, unblinded_path.iter(), Some(destination), session_priv,
1391 |_, onion_packet_ss, ephemeral_pubkey, control_tlvs_ss, unblinded_pk_opt, enc_payload_opt| {
1392 if num_unblinded_hops != 0 && unblinded_path_idx < num_unblinded_hops {
1393 if let Some(ss) = prev_control_tlvs_ss.take() {
1394 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(
1396 next_hop: NextMessageHop::NodeId(unblinded_pk_opt.unwrap()),
1397 next_blinding_override: None,
1401 prev_control_tlvs_ss = Some(control_tlvs_ss);
1402 unblinded_path_idx += 1;
1403 } else if let Some((intro_node_id, blinding_pt)) = intro_node_id_blinding_pt.take() {
1404 if let Some(control_tlvs_ss) = prev_control_tlvs_ss.take() {
1405 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
1406 next_hop: NextMessageHop::NodeId(intro_node_id),
1407 next_blinding_override: Some(blinding_pt),
1408 })), control_tlvs_ss));
1411 if blinded_path_idx < num_blinded_hops.saturating_sub(1) && enc_payload_opt.is_some() {
1412 payloads.push((Payload::Forward(ForwardControlTlvs::Blinded(enc_payload_opt.unwrap())),
1414 blinded_path_idx += 1;
1415 } else if let Some(encrypted_payload) = enc_payload_opt {
1416 final_control_tlvs = Some(ReceiveControlTlvs::Blinded(encrypted_payload));
1417 prev_control_tlvs_ss = Some(control_tlvs_ss);
1420 let (rho, mu) = onion_utils::gen_rho_mu_from_shared_secret(onion_packet_ss.as_ref());
1421 onion_packet_keys.push(onion_utils::OnionKeys {
1423 shared_secret: onion_packet_ss,
1425 blinding_factor: [0; 32],
1431 ).map_err(|e| SendError::Secp256k1(e))?;
1433 if let Some(control_tlvs) = final_control_tlvs {
1434 payloads.push((Payload::Receive {
1436 reply_path: reply_path.take(),
1438 }, prev_control_tlvs_ss.unwrap()));
1440 payloads.push((Payload::Receive {
1441 control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id: None, }),
1442 reply_path: reply_path.take(),
1444 }, prev_control_tlvs_ss.unwrap()));
1447 Ok((payloads, onion_packet_keys))
1450 /// Errors if the serialized payload size exceeds onion_message::BIG_PACKET_HOP_DATA_LEN
1451 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, ()> {
1453 // "`len` allows larger messages to be sent than the standard 1300 bytes allowed for an HTLC
1454 // onion, but this should be used sparingly as it is reduces anonymity set, hence the
1455 // recommendation that it either look like an HTLC onion, or if larger, be a fixed size."
1456 let payloads_ser_len = onion_utils::payloads_serialized_length(&payloads);
1457 let hop_data_len = if payloads_ser_len <= SMALL_PACKET_HOP_DATA_LEN {
1458 SMALL_PACKET_HOP_DATA_LEN
1459 } else if payloads_ser_len <= BIG_PACKET_HOP_DATA_LEN {
1460 BIG_PACKET_HOP_DATA_LEN
1461 } else { return Err(()) };
1463 onion_utils::construct_onion_message_packet::<_, _>(
1464 payloads, onion_keys, prng_seed, hop_data_len)