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 the [`OnionMessenger`]. See its docs for
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;
19 use crate::blinded_path::message::{advance_path_by_one, ForwardTlvs, ReceiveTlvs};
20 use crate::blinded_path::utils;
21 use crate::sign::{EntropySource, KeysManager, NodeSigner, Recipient};
22 #[cfg(not(c_bindings))]
23 use crate::ln::channelmanager::{SimpleArcChannelManager, SimpleRefChannelManager};
24 use crate::ln::features::{InitFeatures, NodeFeatures};
25 use crate::ln::msgs::{self, OnionMessage, OnionMessageHandler};
26 use crate::ln::onion_utils;
27 use crate::ln::peer_handler::IgnoringMessageHandler;
28 pub use super::packet::OnionMessageContents;
29 use super::packet::ParsedOnionMessageContents;
30 use super::offers::OffersMessageHandler;
31 use super::packet::{BIG_PACKET_HOP_DATA_LEN, ForwardControlTlvs, Packet, Payload, ReceiveControlTlvs, SMALL_PACKET_HOP_DATA_LEN};
32 use crate::util::logger::Logger;
33 use crate::util::ser::Writeable;
38 use crate::sync::{Arc, Mutex};
39 use crate::prelude::*;
41 /// A sender, receiver and forwarder of [`OnionMessage`]s.
43 /// # Handling Messages
45 /// `OnionMessenger` implements [`OnionMessageHandler`], making it responsible for either forwarding
46 /// messages to peers or delegating to the appropriate handler for the message type. Currently, the
47 /// available handlers are:
48 /// * [`OffersMessageHandler`], for responding to [`InvoiceRequest`]s and paying [`Bolt12Invoice`]s
49 /// * [`CustomOnionMessageHandler`], for handling user-defined message types
51 /// # Sending Messages
53 /// [`OnionMessage`]s are sent initially using [`OnionMessenger::send_onion_message`]. When handling
54 /// a message, the matched handler may return a response message which `OnionMessenger` will send
60 /// # extern crate bitcoin;
61 /// # use bitcoin::hashes::_export::_core::time::Duration;
62 /// # use bitcoin::hashes::hex::FromHex;
63 /// # use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey};
64 /// # use lightning::blinded_path::BlindedPath;
65 /// # use lightning::sign::KeysManager;
66 /// # use lightning::ln::peer_handler::IgnoringMessageHandler;
67 /// # use lightning::onion_message::{OnionMessageContents, Destination, MessageRouter, OnionMessagePath, OnionMessenger};
68 /// # use lightning::util::logger::{Logger, Record};
69 /// # use lightning::util::ser::{Writeable, Writer};
70 /// # use lightning::io;
71 /// # use std::sync::Arc;
72 /// # struct FakeLogger;
73 /// # impl Logger for FakeLogger {
74 /// # fn log(&self, record: Record) { println!("{:?}" , record); }
76 /// # struct FakeMessageRouter {}
77 /// # impl MessageRouter for FakeMessageRouter {
78 /// # fn find_path(&self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination) -> Result<OnionMessagePath, ()> {
79 /// # let secp_ctx = Secp256k1::new();
80 /// # let node_secret = SecretKey::from_slice(&<Vec<u8>>::from_hex("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
81 /// # let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
82 /// # let hop_node_id2 = hop_node_id1;
83 /// # Ok(OnionMessagePath {
84 /// # intermediate_nodes: vec![hop_node_id1, hop_node_id2],
89 /// # let seed = [42u8; 32];
90 /// # let time = Duration::from_secs(123456);
91 /// # let keys_manager = KeysManager::new(&seed, time.as_secs(), time.subsec_nanos());
92 /// # let logger = Arc::new(FakeLogger {});
93 /// # let node_secret = SecretKey::from_slice(&<Vec<u8>>::from_hex("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
94 /// # let secp_ctx = Secp256k1::new();
95 /// # let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
96 /// # let (hop_node_id3, hop_node_id4) = (hop_node_id1, hop_node_id1);
97 /// # let destination_node_id = hop_node_id1;
98 /// # let message_router = Arc::new(FakeMessageRouter {});
99 /// # let custom_message_handler = IgnoringMessageHandler {};
100 /// # let offers_message_handler = IgnoringMessageHandler {};
101 /// // Create the onion messenger. This must use the same `keys_manager` as is passed to your
102 /// // ChannelManager.
103 /// let onion_messenger = OnionMessenger::new(
104 /// &keys_manager, &keys_manager, logger, message_router, &offers_message_handler,
105 /// &custom_message_handler
108 /// # #[derive(Debug)]
109 /// # struct YourCustomMessage {}
110 /// impl Writeable for YourCustomMessage {
111 /// fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
113 /// // Write your custom onion message to `w`
116 /// impl OnionMessageContents for YourCustomMessage {
117 /// fn tlv_type(&self) -> u64 {
118 /// # let your_custom_message_type = 42;
119 /// your_custom_message_type
122 /// // Send a custom onion message to a node id.
123 /// let destination = Destination::Node(destination_node_id);
124 /// let reply_path = None;
125 /// # let message = YourCustomMessage {};
126 /// onion_messenger.send_onion_message(message, destination, reply_path);
128 /// // Create a blinded path to yourself, for someone to send an onion message to.
129 /// # let your_node_id = hop_node_id1;
130 /// let hops = [hop_node_id3, hop_node_id4, your_node_id];
131 /// let blinded_path = BlindedPath::new_for_message(&hops, &keys_manager, &secp_ctx).unwrap();
133 /// // Send a custom onion message to a blinded path.
134 /// let destination = Destination::BlindedPath(blinded_path);
135 /// let reply_path = None;
136 /// # let message = YourCustomMessage {};
137 /// onion_messenger.send_onion_message(message, destination, reply_path);
140 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
141 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
142 pub struct OnionMessenger<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref>
144 ES::Target: EntropySource,
145 NS::Target: NodeSigner,
147 MR::Target: MessageRouter,
148 OMH::Target: OffersMessageHandler,
149 CMH:: Target: CustomOnionMessageHandler,
154 message_buffers: Mutex<HashMap<PublicKey, OnionMessageBuffer>>,
155 secp_ctx: Secp256k1<secp256k1::All>,
161 /// [`OnionMessage`]s buffered to be sent.
162 enum OnionMessageBuffer {
163 /// Messages for a node connected as a peer.
164 ConnectedPeer(VecDeque<OnionMessage>),
166 /// Messages for a node that is not yet connected.
167 PendingConnection(VecDeque<OnionMessage>),
170 impl OnionMessageBuffer {
171 fn pending_messages(&self) -> &VecDeque<OnionMessage> {
173 OnionMessageBuffer::ConnectedPeer(pending_messages) => pending_messages,
174 OnionMessageBuffer::PendingConnection(pending_messages) => pending_messages,
178 fn enqueue_message(&mut self, message: OnionMessage) {
179 let pending_messages = match self {
180 OnionMessageBuffer::ConnectedPeer(pending_messages) => pending_messages,
181 OnionMessageBuffer::PendingConnection(pending_messages) => pending_messages,
184 pending_messages.push_back(message);
187 fn dequeue_message(&mut self) -> Option<OnionMessage> {
188 let pending_messages = match self {
189 OnionMessageBuffer::ConnectedPeer(pending_messages) => pending_messages,
190 OnionMessageBuffer::PendingConnection(pending_messages) => {
191 debug_assert!(false);
196 pending_messages.pop_front()
200 fn release_pending_messages(&mut self) -> VecDeque<OnionMessage> {
201 let pending_messages = match self {
202 OnionMessageBuffer::ConnectedPeer(pending_messages) => pending_messages,
203 OnionMessageBuffer::PendingConnection(pending_messages) => pending_messages,
206 core::mem::take(pending_messages)
209 fn mark_connected(&mut self) {
210 if let OnionMessageBuffer::PendingConnection(pending_messages) = self {
211 let mut new_pending_messages = VecDeque::new();
212 core::mem::swap(pending_messages, &mut new_pending_messages);
213 *self = OnionMessageBuffer::ConnectedPeer(new_pending_messages);
218 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
220 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
221 /// enqueued for sending.
222 #[cfg(not(c_bindings))]
223 pub struct PendingOnionMessage<T: OnionMessageContents> {
224 /// The message contents to send in an [`OnionMessage`].
227 /// The destination of the message.
228 pub destination: Destination,
230 /// A reply path to include in the [`OnionMessage`] for a response.
231 pub reply_path: Option<BlindedPath>,
235 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
237 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
238 /// enqueued for sending.
239 pub type PendingOnionMessage<T: OnionMessageContents> = (T, Destination, Option<BlindedPath>);
241 pub(crate) fn new_pending_onion_message<T: OnionMessageContents>(
242 contents: T, destination: Destination, reply_path: Option<BlindedPath>
243 ) -> PendingOnionMessage<T> {
244 #[cfg(not(c_bindings))]
245 return PendingOnionMessage { contents, destination, reply_path };
247 return (contents, destination, reply_path);
250 /// A trait defining behavior for routing an [`OnionMessage`].
251 pub trait MessageRouter {
252 /// Returns a route for sending an [`OnionMessage`] to the given [`Destination`].
254 &self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
255 ) -> Result<OnionMessagePath, ()>;
258 /// A [`MessageRouter`] that can only route to a directly connected [`Destination`].
259 pub struct DefaultMessageRouter;
261 impl MessageRouter for DefaultMessageRouter {
263 &self, _sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
264 ) -> Result<OnionMessagePath, ()> {
265 if peers.contains(&destination.first_node()) {
266 Ok(OnionMessagePath { intermediate_nodes: vec![], destination })
273 /// A path for sending an [`OnionMessage`].
275 pub struct OnionMessagePath {
276 /// Nodes on the path between the sender and the destination.
277 pub intermediate_nodes: Vec<PublicKey>,
279 /// The recipient of the message.
280 pub destination: Destination,
283 /// The destination of an onion message.
285 pub enum Destination {
286 /// We're sending this onion message to a node.
288 /// We're sending this onion message to a blinded path.
289 BlindedPath(BlindedPath),
293 pub(super) fn num_hops(&self) -> usize {
295 Destination::Node(_) => 1,
296 Destination::BlindedPath(BlindedPath { blinded_hops, .. }) => blinded_hops.len(),
300 fn first_node(&self) -> PublicKey {
302 Destination::Node(node_id) => *node_id,
303 Destination::BlindedPath(BlindedPath { introduction_node_id: node_id, .. }) => *node_id,
308 /// Result of successfully [sending an onion message].
310 /// [sending an onion message]: OnionMessenger::send_onion_message
311 #[derive(Debug, PartialEq, Eq)]
312 pub enum SendSuccess {
313 /// The message was buffered and will be sent once it is processed by
314 /// [`OnionMessageHandler::next_onion_message_for_peer`].
318 /// Errors that may occur when [sending an onion message].
320 /// [sending an onion message]: OnionMessenger::send_onion_message
321 #[derive(Debug, PartialEq, Eq)]
323 /// Errored computing onion message packet keys.
324 Secp256k1(secp256k1::Error),
325 /// Because implementations such as Eclair will drop onion messages where the message packet
326 /// exceeds 32834 bytes, we refuse to send messages where the packet exceeds this size.
328 /// The provided [`Destination`] was an invalid [`BlindedPath`] due to not having any blinded
331 /// Our next-hop peer was offline or does not support onion message forwarding.
333 /// A path from the sender to the destination could not be found by the [`MessageRouter`].
335 /// Onion message contents must have a TLV type >= 64.
337 /// Our next-hop peer's buffer was full or our total outbound buffer was full.
339 /// Failed to retrieve our node id from the provided [`NodeSigner`].
341 /// [`NodeSigner`]: crate::sign::NodeSigner
343 /// We attempted to send to a blinded path where we are the introduction node, and failed to
344 /// advance the blinded path to make the second hop the new introduction node. Either
345 /// [`NodeSigner::ecdh`] failed, we failed to tweak the current blinding point to get the
346 /// new blinding point, or we were attempting to send to ourselves.
347 BlindedPathAdvanceFailed,
350 /// Handler for custom onion messages. If you are using [`SimpleArcOnionMessenger`],
351 /// [`SimpleRefOnionMessenger`], or prefer to ignore inbound custom onion messages,
352 /// [`IgnoringMessageHandler`] must be provided to [`OnionMessenger::new`]. Otherwise, a custom
353 /// implementation of this trait must be provided, with [`CustomMessage`] specifying the supported
356 /// See [`OnionMessenger`] for example usage.
358 /// [`IgnoringMessageHandler`]: crate::ln::peer_handler::IgnoringMessageHandler
359 /// [`CustomMessage`]: Self::CustomMessage
360 pub trait CustomOnionMessageHandler {
361 /// The message known to the handler. To support multiple message types, you may want to make this
362 /// an enum with a variant for each supported message.
363 type CustomMessage: OnionMessageContents;
365 /// Called with the custom message that was received, returning a response to send, if any.
367 /// The returned [`Self::CustomMessage`], if any, is enqueued to be sent by [`OnionMessenger`].
368 fn handle_custom_message(&self, msg: Self::CustomMessage) -> Option<Self::CustomMessage>;
370 /// Read a custom message of type `message_type` from `buffer`, returning `Ok(None)` if the
371 /// message type is unknown.
372 fn read_custom_message<R: io::Read>(&self, message_type: u64, buffer: &mut R) -> Result<Option<Self::CustomMessage>, msgs::DecodeError>;
374 /// Releases any [`Self::CustomMessage`]s that need to be sent.
376 /// Typically, this is used for messages initiating a message flow rather than in response to
377 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
378 #[cfg(not(c_bindings))]
379 fn release_pending_custom_messages(&self) -> Vec<PendingOnionMessage<Self::CustomMessage>>;
381 /// Releases any [`Self::CustomMessage`]s that need to be sent.
383 /// Typically, this is used for messages initiating a message flow rather than in response to
384 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
386 fn release_pending_custom_messages(&self) -> Vec<(Self::CustomMessage, Destination, Option<BlindedPath>)>;
389 /// A processed incoming onion message, containing either a Forward (another onion message)
390 /// or a Receive payload with decrypted contents.
391 pub enum PeeledOnion<T: OnionMessageContents> {
392 /// Forwarded onion, with the next node id and a new onion
393 Forward(PublicKey, OnionMessage),
394 /// Received onion message, with decrypted contents, path_id, and reply path
395 Receive(ParsedOnionMessageContents<T>, Option<[u8; 32]>, Option<BlindedPath>)
398 /// Creates an [`OnionMessage`] with the given `contents` for sending to the destination of
401 /// Returns both the node id of the peer to send the message to and the message itself.
402 pub fn create_onion_message<ES: Deref, NS: Deref, T: OnionMessageContents>(
403 entropy_source: &ES, node_signer: &NS, secp_ctx: &Secp256k1<secp256k1::All>,
404 path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
405 ) -> Result<(PublicKey, OnionMessage), SendError>
407 ES::Target: EntropySource,
408 NS::Target: NodeSigner,
410 let OnionMessagePath { intermediate_nodes, mut destination } = path;
411 if let Destination::BlindedPath(BlindedPath { ref blinded_hops, .. }) = destination {
412 if blinded_hops.is_empty() {
413 return Err(SendError::TooFewBlindedHops);
417 if contents.tlv_type() < 64 { return Err(SendError::InvalidMessage) }
419 // If we are sending straight to a blinded path and we are the introduction node, we need to
420 // advance the blinded path by 1 hop so the second hop is the new introduction node.
421 if intermediate_nodes.len() == 0 {
422 if let Destination::BlindedPath(ref mut blinded_path) = destination {
423 let our_node_id = node_signer.get_node_id(Recipient::Node)
424 .map_err(|()| SendError::GetNodeIdFailed)?;
425 if blinded_path.introduction_node_id == our_node_id {
426 advance_path_by_one(blinded_path, node_signer, &secp_ctx)
427 .map_err(|()| SendError::BlindedPathAdvanceFailed)?;
432 let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
433 let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
434 let (first_node_id, blinding_point) = if let Some(first_node_id) = intermediate_nodes.first() {
435 (*first_node_id, PublicKey::from_secret_key(&secp_ctx, &blinding_secret))
438 Destination::Node(pk) => (pk, PublicKey::from_secret_key(&secp_ctx, &blinding_secret)),
439 Destination::BlindedPath(BlindedPath { introduction_node_id, blinding_point, .. }) =>
440 (introduction_node_id, blinding_point),
443 let (packet_payloads, packet_keys) = packet_payloads_and_keys(
444 &secp_ctx, &intermediate_nodes, destination, contents, reply_path, &blinding_secret)
445 .map_err(|e| SendError::Secp256k1(e))?;
447 let prng_seed = entropy_source.get_secure_random_bytes();
448 let onion_routing_packet = construct_onion_message_packet(
449 packet_payloads, packet_keys, prng_seed).map_err(|()| SendError::TooBigPacket)?;
451 Ok((first_node_id, OnionMessage {
457 /// Decode one layer of an incoming [`OnionMessage`].
459 /// Returns either the next layer of the onion for forwarding or the decrypted content for the
461 pub fn peel_onion_message<NS: Deref, L: Deref, CMH: Deref>(
462 msg: &OnionMessage, secp_ctx: &Secp256k1<secp256k1::All>, node_signer: NS, logger: L,
464 ) -> Result<PeeledOnion<<<CMH>::Target as CustomOnionMessageHandler>::CustomMessage>, ()>
466 NS::Target: NodeSigner,
468 CMH::Target: CustomOnionMessageHandler,
470 let control_tlvs_ss = match node_signer.ecdh(Recipient::Node, &msg.blinding_point, None) {
473 log_error!(logger, "Failed to retrieve node secret: {:?}", e);
477 let onion_decode_ss = {
478 let blinding_factor = {
479 let mut hmac = HmacEngine::<Sha256>::new(b"blinded_node_id");
480 hmac.input(control_tlvs_ss.as_ref());
481 Hmac::from_engine(hmac).to_byte_array()
483 match node_signer.ecdh(Recipient::Node, &msg.onion_routing_packet.public_key,
484 Some(&Scalar::from_be_bytes(blinding_factor).unwrap()))
486 Ok(ss) => ss.secret_bytes(),
488 log_trace!(logger, "Failed to compute onion packet shared secret");
493 match onion_utils::decode_next_untagged_hop(
494 onion_decode_ss, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
495 (control_tlvs_ss, custom_handler.deref(), logger.deref())
497 Ok((Payload::Receive::<ParsedOnionMessageContents<<<CMH as Deref>::Target as CustomOnionMessageHandler>::CustomMessage>> {
498 message, control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id }), reply_path,
500 Ok(PeeledOnion::Receive(message, path_id, reply_path))
502 Ok((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
503 next_node_id, next_blinding_override
504 })), Some((next_hop_hmac, new_packet_bytes)))) => {
505 // TODO: we need to check whether `next_node_id` is our node, in which case this is a dummy
506 // blinded hop and this onion message is destined for us. In this situation, we should keep
507 // unwrapping the onion layers to get to the final payload. Since we don't have the option
508 // of creating blinded paths with dummy hops currently, we should be ok to not handle this
510 let new_pubkey = match onion_utils::next_hop_pubkey(&secp_ctx, msg.onion_routing_packet.public_key, &onion_decode_ss) {
513 log_trace!(logger, "Failed to compute next hop packet pubkey: {}", e);
517 let outgoing_packet = Packet {
519 public_key: new_pubkey,
520 hop_data: new_packet_bytes,
523 let onion_message = OnionMessage {
524 blinding_point: match next_blinding_override {
525 Some(blinding_point) => blinding_point,
527 match onion_utils::next_hop_pubkey(
528 &secp_ctx, msg.blinding_point, control_tlvs_ss.as_ref()
532 log_trace!(logger, "Failed to compute next blinding point: {}", e);
538 onion_routing_packet: outgoing_packet,
541 Ok(PeeledOnion::Forward(next_node_id, onion_message))
544 log_trace!(logger, "Errored decoding onion message packet: {:?}", e);
548 log_trace!(logger, "Received bogus onion message packet, either the sender encoded a final hop as a forwarding hop or vice versa");
554 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref>
555 OnionMessenger<ES, NS, L, MR, OMH, CMH>
557 ES::Target: EntropySource,
558 NS::Target: NodeSigner,
560 MR::Target: MessageRouter,
561 OMH::Target: OffersMessageHandler,
562 CMH::Target: CustomOnionMessageHandler,
564 /// Constructs a new `OnionMessenger` to send, forward, and delegate received onion messages to
565 /// their respective handlers.
567 entropy_source: ES, node_signer: NS, logger: L, message_router: MR, offers_handler: OMH,
570 let mut secp_ctx = Secp256k1::new();
571 secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
575 message_buffers: Mutex::new(HashMap::new()),
584 /// Sends an [`OnionMessage`] with the given `contents` to `destination`.
586 /// See [`OnionMessenger`] for example usage.
587 pub fn send_onion_message<T: OnionMessageContents>(
588 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>
589 ) -> Result<SendSuccess, SendError> {
590 self.find_path_and_enqueue_onion_message(
591 contents, destination, reply_path, format_args!("")
595 fn find_path_and_enqueue_onion_message<T: OnionMessageContents>(
596 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>,
597 log_suffix: fmt::Arguments
598 ) -> Result<SendSuccess, SendError> {
599 let result = self.find_path(destination)
600 .and_then(|path| self.enqueue_onion_message(path, contents, reply_path, log_suffix));
602 match result.as_ref() {
603 Err(SendError::GetNodeIdFailed) => {
604 log_warn!(self.logger, "Unable to retrieve node id {}", log_suffix);
606 Err(SendError::PathNotFound) => {
607 log_trace!(self.logger, "Failed to find path {}", log_suffix);
610 log_trace!(self.logger, "Failed sending onion message {}: {:?}", log_suffix, e);
612 Ok(SendSuccess::Buffered) => {
613 log_trace!(self.logger, "Buffered onion message {}", log_suffix);
620 fn find_path(&self, destination: Destination) -> Result<OnionMessagePath, SendError> {
621 let sender = self.node_signer
622 .get_node_id(Recipient::Node)
623 .map_err(|_| SendError::GetNodeIdFailed)?;
625 let peers = self.message_buffers.lock().unwrap()
627 .filter(|(_, buffer)| matches!(buffer, OnionMessageBuffer::ConnectedPeer(_)))
628 .map(|(node_id, _)| *node_id)
632 .find_path(sender, peers, destination)
633 .map_err(|_| SendError::PathNotFound)
636 fn enqueue_onion_message<T: OnionMessageContents>(
637 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
638 log_suffix: fmt::Arguments
639 ) -> Result<SendSuccess, SendError> {
640 log_trace!(self.logger, "Constructing onion message {}: {:?}", log_suffix, contents);
642 let (first_node_id, onion_message) = create_onion_message(
643 &self.entropy_source, &self.node_signer, &self.secp_ctx, path, contents, reply_path
646 let mut message_buffers = self.message_buffers.lock().unwrap();
647 if outbound_buffer_full(&first_node_id, &message_buffers) {
648 return Err(SendError::BufferFull);
651 match message_buffers.entry(first_node_id) {
652 hash_map::Entry::Vacant(_) => Err(SendError::InvalidFirstHop),
653 hash_map::Entry::Occupied(mut e) => {
654 e.get_mut().enqueue_message(onion_message);
655 Ok(SendSuccess::Buffered)
661 pub(super) fn send_onion_message_using_path<T: OnionMessageContents>(
662 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>
663 ) -> Result<SendSuccess, SendError> {
664 self.enqueue_onion_message(path, contents, reply_path, format_args!(""))
667 fn handle_onion_message_response<T: OnionMessageContents>(
668 &self, response: Option<T>, reply_path: Option<BlindedPath>, log_suffix: fmt::Arguments
670 if let Some(response) = response {
672 Some(reply_path) => {
673 let _ = self.find_path_and_enqueue_onion_message(
674 response, Destination::BlindedPath(reply_path), None, log_suffix
678 log_trace!(self.logger, "Missing reply path {}", log_suffix);
685 pub(super) fn release_pending_msgs(&self) -> HashMap<PublicKey, VecDeque<OnionMessage>> {
686 let mut message_buffers = self.message_buffers.lock().unwrap();
687 let mut msgs = HashMap::new();
688 // We don't want to disconnect the peers by removing them entirely from the original map, so we
689 // release the pending message buffers individually.
690 for (peer_node_id, buffer) in &mut *message_buffers {
691 msgs.insert(*peer_node_id, buffer.release_pending_messages());
697 fn outbound_buffer_full(peer_node_id: &PublicKey, buffer: &HashMap<PublicKey, OnionMessageBuffer>) -> bool {
698 const MAX_TOTAL_BUFFER_SIZE: usize = (1 << 20) * 128;
699 const MAX_PER_PEER_BUFFER_SIZE: usize = (1 << 10) * 256;
700 let mut total_buffered_bytes = 0;
701 let mut peer_buffered_bytes = 0;
702 for (pk, peer_buf) in buffer {
703 for om in peer_buf.pending_messages() {
704 let om_len = om.serialized_length();
705 if pk == peer_node_id {
706 peer_buffered_bytes += om_len;
708 total_buffered_bytes += om_len;
710 if total_buffered_bytes >= MAX_TOTAL_BUFFER_SIZE ||
711 peer_buffered_bytes >= MAX_PER_PEER_BUFFER_SIZE
720 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref> OnionMessageHandler
721 for OnionMessenger<ES, NS, L, MR, OMH, CMH>
723 ES::Target: EntropySource,
724 NS::Target: NodeSigner,
726 MR::Target: MessageRouter,
727 OMH::Target: OffersMessageHandler,
728 CMH::Target: CustomOnionMessageHandler,
730 fn handle_onion_message(&self, _peer_node_id: &PublicKey, msg: &OnionMessage) {
731 match peel_onion_message(
732 msg, &self.secp_ctx, &*self.node_signer, &*self.logger, &*self.custom_handler
734 Ok(PeeledOnion::Receive(message, path_id, reply_path)) => {
737 "Received an onion message with path_id {:02x?} and {} reply_path: {:?}",
738 path_id, if reply_path.is_some() { "a" } else { "no" }, message);
741 ParsedOnionMessageContents::Offers(msg) => {
742 let response = self.offers_handler.handle_message(msg);
743 self.handle_onion_message_response(
744 response, reply_path, format_args!(
745 "when responding to Offers onion message with path_id {:02x?}",
750 ParsedOnionMessageContents::Custom(msg) => {
751 let response = self.custom_handler.handle_custom_message(msg);
752 self.handle_onion_message_response(
753 response, reply_path, format_args!(
754 "when responding to Custom onion message with path_id {:02x?}",
761 Ok(PeeledOnion::Forward(next_node_id, onion_message)) => {
762 let mut message_buffers = self.message_buffers.lock().unwrap();
763 if outbound_buffer_full(&next_node_id, &message_buffers) {
764 log_trace!(self.logger, "Dropping forwarded onion message to peer {:?}: outbound buffer full", next_node_id);
771 .or_insert_with(|| OnionMessageBuffer::ConnectedPeer(VecDeque::new()));
773 match message_buffers.entry(next_node_id) {
774 hash_map::Entry::Occupied(mut e) if matches!(
775 e.get(), OnionMessageBuffer::ConnectedPeer(..)
777 e.get_mut().enqueue_message(onion_message);
778 log_trace!(self.logger, "Forwarding an onion message to peer {}", next_node_id);
781 log_trace!(self.logger, "Dropping forwarded onion message to disconnected peer {:?}", next_node_id);
787 log_error!(self.logger, "Failed to process onion message {:?}", e);
792 fn peer_connected(&self, their_node_id: &PublicKey, init: &msgs::Init, _inbound: bool) -> Result<(), ()> {
793 if init.features.supports_onion_messages() {
794 self.message_buffers.lock().unwrap()
795 .entry(*their_node_id)
796 .or_insert_with(|| OnionMessageBuffer::ConnectedPeer(VecDeque::new()))
799 self.message_buffers.lock().unwrap().remove(their_node_id);
805 fn peer_disconnected(&self, their_node_id: &PublicKey) {
806 match self.message_buffers.lock().unwrap().remove(their_node_id) {
807 Some(OnionMessageBuffer::ConnectedPeer(..)) => {},
808 _ => debug_assert!(false),
812 fn provided_node_features(&self) -> NodeFeatures {
813 let mut features = NodeFeatures::empty();
814 features.set_onion_messages_optional();
818 fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
819 let mut features = InitFeatures::empty();
820 features.set_onion_messages_optional();
824 // Before returning any messages to send for the peer, this method will see if any messages were
825 // enqueued in the handler by users, find a path to the corresponding blinded path's introduction
826 // node, and then enqueue the message for sending to the first peer in the full path.
827 fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<OnionMessage> {
828 // Enqueue any initiating `OffersMessage`s to send.
829 for message in self.offers_handler.release_pending_messages() {
830 #[cfg(not(c_bindings))]
831 let PendingOnionMessage { contents, destination, reply_path } = message;
833 let (contents, destination, reply_path) = message;
834 let _ = self.find_path_and_enqueue_onion_message(
835 contents, destination, reply_path, format_args!("when sending OffersMessage")
839 // Enqueue any initiating `CustomMessage`s to send.
840 for message in self.custom_handler.release_pending_custom_messages() {
841 #[cfg(not(c_bindings))]
842 let PendingOnionMessage { contents, destination, reply_path } = message;
844 let (contents, destination, reply_path) = message;
845 let _ = self.find_path_and_enqueue_onion_message(
846 contents, destination, reply_path, format_args!("when sending CustomMessage")
850 self.message_buffers.lock().unwrap()
851 .get_mut(&peer_node_id)
852 .and_then(|buffer| buffer.dequeue_message())
856 // TODO: parameterize the below Simple* types with OnionMessenger and handle the messages it
858 /// Useful for simplifying the parameters of [`SimpleArcChannelManager`] and
859 /// [`SimpleArcPeerManager`]. See their docs for more details.
861 /// This is not exported to bindings users as type aliases aren't supported in most languages.
863 /// [`SimpleArcChannelManager`]: crate::ln::channelmanager::SimpleArcChannelManager
864 /// [`SimpleArcPeerManager`]: crate::ln::peer_handler::SimpleArcPeerManager
865 #[cfg(not(c_bindings))]
866 pub type SimpleArcOnionMessenger<M, T, F, L> = OnionMessenger<
870 Arc<DefaultMessageRouter>,
871 Arc<SimpleArcChannelManager<M, T, F, L>>,
872 IgnoringMessageHandler
875 /// Useful for simplifying the parameters of [`SimpleRefChannelManager`] and
876 /// [`SimpleRefPeerManager`]. See their docs for more details.
878 /// This is not exported to bindings users as type aliases aren't supported in most languages.
880 /// [`SimpleRefChannelManager`]: crate::ln::channelmanager::SimpleRefChannelManager
881 /// [`SimpleRefPeerManager`]: crate::ln::peer_handler::SimpleRefPeerManager
882 #[cfg(not(c_bindings))]
883 pub type SimpleRefOnionMessenger<
884 'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, 'i, 'j, M, T, F, L
889 &'i DefaultMessageRouter,
890 &'j SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, M, T, F, L>,
891 IgnoringMessageHandler
894 /// Construct onion packet payloads and keys for sending an onion message along the given
895 /// `unblinded_path` to the given `destination`.
896 fn packet_payloads_and_keys<T: OnionMessageContents, S: secp256k1::Signing + secp256k1::Verification>(
897 secp_ctx: &Secp256k1<S>, unblinded_path: &[PublicKey], destination: Destination, message: T,
898 mut reply_path: Option<BlindedPath>, session_priv: &SecretKey
899 ) -> Result<(Vec<(Payload<T>, [u8; 32])>, Vec<onion_utils::OnionKeys>), secp256k1::Error> {
900 let num_hops = unblinded_path.len() + destination.num_hops();
901 let mut payloads = Vec::with_capacity(num_hops);
902 let mut onion_packet_keys = Vec::with_capacity(num_hops);
904 let (mut intro_node_id_blinding_pt, num_blinded_hops) = if let Destination::BlindedPath(BlindedPath {
905 introduction_node_id, blinding_point, blinded_hops }) = &destination {
906 (Some((*introduction_node_id, *blinding_point)), blinded_hops.len()) } else { (None, 0) };
907 let num_unblinded_hops = num_hops - num_blinded_hops;
909 let mut unblinded_path_idx = 0;
910 let mut blinded_path_idx = 0;
911 let mut prev_control_tlvs_ss = None;
912 let mut final_control_tlvs = None;
913 utils::construct_keys_callback(secp_ctx, unblinded_path.iter(), Some(destination), session_priv,
914 |_, onion_packet_ss, ephemeral_pubkey, control_tlvs_ss, unblinded_pk_opt, enc_payload_opt| {
915 if num_unblinded_hops != 0 && unblinded_path_idx < num_unblinded_hops {
916 if let Some(ss) = prev_control_tlvs_ss.take() {
917 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(
919 next_node_id: unblinded_pk_opt.unwrap(),
920 next_blinding_override: None,
924 prev_control_tlvs_ss = Some(control_tlvs_ss);
925 unblinded_path_idx += 1;
926 } else if let Some((intro_node_id, blinding_pt)) = intro_node_id_blinding_pt.take() {
927 if let Some(control_tlvs_ss) = prev_control_tlvs_ss.take() {
928 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
929 next_node_id: intro_node_id,
930 next_blinding_override: Some(blinding_pt),
931 })), control_tlvs_ss));
934 if blinded_path_idx < num_blinded_hops.saturating_sub(1) && enc_payload_opt.is_some() {
935 payloads.push((Payload::Forward(ForwardControlTlvs::Blinded(enc_payload_opt.unwrap())),
937 blinded_path_idx += 1;
938 } else if let Some(encrypted_payload) = enc_payload_opt {
939 final_control_tlvs = Some(ReceiveControlTlvs::Blinded(encrypted_payload));
940 prev_control_tlvs_ss = Some(control_tlvs_ss);
943 let (rho, mu) = onion_utils::gen_rho_mu_from_shared_secret(onion_packet_ss.as_ref());
944 onion_packet_keys.push(onion_utils::OnionKeys {
946 shared_secret: onion_packet_ss,
948 blinding_factor: [0; 32],
956 if let Some(control_tlvs) = final_control_tlvs {
957 payloads.push((Payload::Receive {
959 reply_path: reply_path.take(),
961 }, prev_control_tlvs_ss.unwrap()));
963 payloads.push((Payload::Receive {
964 control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id: None, }),
965 reply_path: reply_path.take(),
967 }, prev_control_tlvs_ss.unwrap()));
970 Ok((payloads, onion_packet_keys))
973 /// Errors if the serialized payload size exceeds onion_message::BIG_PACKET_HOP_DATA_LEN
974 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, ()> {
976 // "`len` allows larger messages to be sent than the standard 1300 bytes allowed for an HTLC
977 // onion, but this should be used sparingly as it is reduces anonymity set, hence the
978 // recommendation that it either look like an HTLC onion, or if larger, be a fixed size."
979 let payloads_ser_len = onion_utils::payloads_serialized_length(&payloads);
980 let hop_data_len = if payloads_ser_len <= SMALL_PACKET_HOP_DATA_LEN {
981 SMALL_PACKET_HOP_DATA_LEN
982 } else if payloads_ser_len <= BIG_PACKET_HOP_DATA_LEN {
983 BIG_PACKET_HOP_DATA_LEN
984 } else { return Err(()) };
986 onion_utils::construct_onion_message_packet::<_, _>(
987 payloads, onion_keys, prng_seed, hop_data_len)