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 /// # unimplemented!()
82 /// # let seed = [42u8; 32];
83 /// # let time = Duration::from_secs(123456);
84 /// # let keys_manager = KeysManager::new(&seed, time.as_secs(), time.subsec_nanos());
85 /// # let logger = Arc::new(FakeLogger {});
86 /// # let node_secret = SecretKey::from_slice(&<Vec<u8>>::from_hex("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
87 /// # let secp_ctx = Secp256k1::new();
88 /// # let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
89 /// # let (hop_node_id2, hop_node_id3, hop_node_id4) = (hop_node_id1, hop_node_id1, hop_node_id1);
90 /// # let destination_node_id = hop_node_id1;
91 /// # let message_router = Arc::new(FakeMessageRouter {});
92 /// # let custom_message_handler = IgnoringMessageHandler {};
93 /// # let offers_message_handler = IgnoringMessageHandler {};
94 /// // Create the onion messenger. This must use the same `keys_manager` as is passed to your
95 /// // ChannelManager.
96 /// let onion_messenger = OnionMessenger::new(
97 /// &keys_manager, &keys_manager, logger, message_router, &offers_message_handler,
98 /// &custom_message_handler
101 /// # #[derive(Debug)]
102 /// # struct YourCustomMessage {}
103 /// impl Writeable for YourCustomMessage {
104 /// fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
106 /// // Write your custom onion message to `w`
109 /// impl OnionMessageContents for YourCustomMessage {
110 /// fn tlv_type(&self) -> u64 {
111 /// # let your_custom_message_type = 42;
112 /// your_custom_message_type
115 /// // Send a custom onion message to a node id.
116 /// let path = OnionMessagePath {
117 /// intermediate_nodes: vec![hop_node_id1, hop_node_id2],
118 /// destination: Destination::Node(destination_node_id),
120 /// let reply_path = None;
121 /// # let message = YourCustomMessage {};
122 /// onion_messenger.send_onion_message(path, message, reply_path);
124 /// // Create a blinded path to yourself, for someone to send an onion message to.
125 /// # let your_node_id = hop_node_id1;
126 /// let hops = [hop_node_id3, hop_node_id4, your_node_id];
127 /// let blinded_path = BlindedPath::new_for_message(&hops, &keys_manager, &secp_ctx).unwrap();
129 /// // Send a custom onion message to a blinded path.
130 /// let path = OnionMessagePath {
131 /// intermediate_nodes: vec![hop_node_id1, hop_node_id2],
132 /// destination: Destination::BlindedPath(blinded_path),
134 /// let reply_path = None;
135 /// # let message = YourCustomMessage {};
136 /// onion_messenger.send_onion_message(path, message, reply_path);
139 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
140 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
141 pub struct OnionMessenger<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref>
143 ES::Target: EntropySource,
144 NS::Target: NodeSigner,
146 MR::Target: MessageRouter,
147 OMH::Target: OffersMessageHandler,
148 CMH:: Target: CustomOnionMessageHandler,
153 message_buffers: Mutex<HashMap<PublicKey, OnionMessageBuffer>>,
154 secp_ctx: Secp256k1<secp256k1::All>,
160 /// [`OnionMessage`]s buffered to be sent.
161 enum OnionMessageBuffer {
162 /// Messages for a node connected as a peer.
163 ConnectedPeer(VecDeque<OnionMessage>),
165 /// Messages for a node that is not yet connected.
166 PendingConnection(VecDeque<OnionMessage>),
169 impl OnionMessageBuffer {
170 fn pending_messages(&self) -> &VecDeque<OnionMessage> {
172 OnionMessageBuffer::ConnectedPeer(pending_messages) => pending_messages,
173 OnionMessageBuffer::PendingConnection(pending_messages) => pending_messages,
177 fn enqueue_message(&mut self, message: OnionMessage) {
178 let pending_messages = match self {
179 OnionMessageBuffer::ConnectedPeer(pending_messages) => pending_messages,
180 OnionMessageBuffer::PendingConnection(pending_messages) => pending_messages,
183 pending_messages.push_back(message);
186 fn dequeue_message(&mut self) -> Option<OnionMessage> {
187 let pending_messages = match self {
188 OnionMessageBuffer::ConnectedPeer(pending_messages) => pending_messages,
189 OnionMessageBuffer::PendingConnection(pending_messages) => {
190 debug_assert!(false);
195 pending_messages.pop_front()
199 fn release_pending_messages(&mut self) -> VecDeque<OnionMessage> {
200 let pending_messages = match self {
201 OnionMessageBuffer::ConnectedPeer(pending_messages) => pending_messages,
202 OnionMessageBuffer::PendingConnection(pending_messages) => pending_messages,
205 core::mem::take(pending_messages)
208 fn mark_connected(&mut self) {
209 if let OnionMessageBuffer::PendingConnection(pending_messages) = self {
210 let mut new_pending_messages = VecDeque::new();
211 core::mem::swap(pending_messages, &mut new_pending_messages);
212 *self = OnionMessageBuffer::ConnectedPeer(new_pending_messages);
217 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
219 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
220 /// enqueued for sending.
221 #[cfg(not(c_bindings))]
222 pub struct PendingOnionMessage<T: OnionMessageContents> {
223 /// The message contents to send in an [`OnionMessage`].
226 /// The destination of the message.
227 pub destination: Destination,
229 /// A reply path to include in the [`OnionMessage`] for a response.
230 pub reply_path: Option<BlindedPath>,
234 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
236 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
237 /// enqueued for sending.
238 pub type PendingOnionMessage<T: OnionMessageContents> = (T, Destination, Option<BlindedPath>);
240 pub(crate) fn new_pending_onion_message<T: OnionMessageContents>(
241 contents: T, destination: Destination, reply_path: Option<BlindedPath>
242 ) -> PendingOnionMessage<T> {
243 #[cfg(not(c_bindings))]
244 return PendingOnionMessage { contents, destination, reply_path };
246 return (contents, destination, reply_path);
249 /// A trait defining behavior for routing an [`OnionMessage`].
250 pub trait MessageRouter {
251 /// Returns a route for sending an [`OnionMessage`] to the given [`Destination`].
253 &self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
254 ) -> Result<OnionMessagePath, ()>;
257 /// A [`MessageRouter`] that can only route to a directly connected [`Destination`].
258 pub struct DefaultMessageRouter;
260 impl MessageRouter for DefaultMessageRouter {
262 &self, _sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
263 ) -> Result<OnionMessagePath, ()> {
264 if peers.contains(&destination.first_node()) {
265 Ok(OnionMessagePath { intermediate_nodes: vec![], destination })
272 /// A path for sending an [`OnionMessage`].
274 pub struct OnionMessagePath {
275 /// Nodes on the path between the sender and the destination.
276 pub intermediate_nodes: Vec<PublicKey>,
278 /// The recipient of the message.
279 pub destination: Destination,
282 /// The destination of an onion message.
284 pub enum Destination {
285 /// We're sending this onion message to a node.
287 /// We're sending this onion message to a blinded path.
288 BlindedPath(BlindedPath),
292 pub(super) fn num_hops(&self) -> usize {
294 Destination::Node(_) => 1,
295 Destination::BlindedPath(BlindedPath { blinded_hops, .. }) => blinded_hops.len(),
299 fn first_node(&self) -> PublicKey {
301 Destination::Node(node_id) => *node_id,
302 Destination::BlindedPath(BlindedPath { introduction_node_id: node_id, .. }) => *node_id,
307 /// Errors that may occur when [sending an onion message].
309 /// [sending an onion message]: OnionMessenger::send_onion_message
310 #[derive(Debug, PartialEq, Eq)]
312 /// Errored computing onion message packet keys.
313 Secp256k1(secp256k1::Error),
314 /// Because implementations such as Eclair will drop onion messages where the message packet
315 /// exceeds 32834 bytes, we refuse to send messages where the packet exceeds this size.
317 /// The provided [`Destination`] was an invalid [`BlindedPath`] due to not having any blinded
320 /// Our next-hop peer was offline or does not support onion message forwarding.
322 /// Onion message contents must have a TLV type >= 64.
324 /// Our next-hop peer's buffer was full or our total outbound buffer was full.
326 /// Failed to retrieve our node id from the provided [`NodeSigner`].
328 /// [`NodeSigner`]: crate::sign::NodeSigner
330 /// We attempted to send to a blinded path where we are the introduction node, and failed to
331 /// advance the blinded path to make the second hop the new introduction node. Either
332 /// [`NodeSigner::ecdh`] failed, we failed to tweak the current blinding point to get the
333 /// new blinding point, or we were attempting to send to ourselves.
334 BlindedPathAdvanceFailed,
337 /// Handler for custom onion messages. If you are using [`SimpleArcOnionMessenger`],
338 /// [`SimpleRefOnionMessenger`], or prefer to ignore inbound custom onion messages,
339 /// [`IgnoringMessageHandler`] must be provided to [`OnionMessenger::new`]. Otherwise, a custom
340 /// implementation of this trait must be provided, with [`CustomMessage`] specifying the supported
343 /// See [`OnionMessenger`] for example usage.
345 /// [`IgnoringMessageHandler`]: crate::ln::peer_handler::IgnoringMessageHandler
346 /// [`CustomMessage`]: Self::CustomMessage
347 pub trait CustomOnionMessageHandler {
348 /// The message known to the handler. To support multiple message types, you may want to make this
349 /// an enum with a variant for each supported message.
350 type CustomMessage: OnionMessageContents;
352 /// Called with the custom message that was received, returning a response to send, if any.
354 /// The returned [`Self::CustomMessage`], if any, is enqueued to be sent by [`OnionMessenger`].
355 fn handle_custom_message(&self, msg: Self::CustomMessage) -> Option<Self::CustomMessage>;
357 /// Read a custom message of type `message_type` from `buffer`, returning `Ok(None)` if the
358 /// message type is unknown.
359 fn read_custom_message<R: io::Read>(&self, message_type: u64, buffer: &mut R) -> Result<Option<Self::CustomMessage>, msgs::DecodeError>;
361 /// Releases any [`Self::CustomMessage`]s that need to be sent.
363 /// Typically, this is used for messages initiating a message flow rather than in response to
364 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
365 #[cfg(not(c_bindings))]
366 fn release_pending_custom_messages(&self) -> Vec<PendingOnionMessage<Self::CustomMessage>>;
368 /// Releases any [`Self::CustomMessage`]s that need to be sent.
370 /// Typically, this is used for messages initiating a message flow rather than in response to
371 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
373 fn release_pending_custom_messages(&self) -> Vec<(Self::CustomMessage, Destination, Option<BlindedPath>)>;
376 /// A processed incoming onion message, containing either a Forward (another onion message)
377 /// or a Receive payload with decrypted contents.
378 pub enum PeeledOnion<T: OnionMessageContents> {
379 /// Forwarded onion, with the next node id and a new onion
380 Forward(PublicKey, OnionMessage),
381 /// Received onion message, with decrypted contents, path_id, and reply path
382 Receive(ParsedOnionMessageContents<T>, Option<[u8; 32]>, Option<BlindedPath>)
385 /// Creates an [`OnionMessage`] with the given `contents` for sending to the destination of
388 /// Returns both the node id of the peer to send the message to and the message itself.
389 pub fn create_onion_message<ES: Deref, NS: Deref, T: OnionMessageContents>(
390 entropy_source: &ES, node_signer: &NS, secp_ctx: &Secp256k1<secp256k1::All>,
391 path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
392 ) -> Result<(PublicKey, OnionMessage), SendError>
394 ES::Target: EntropySource,
395 NS::Target: NodeSigner,
397 let OnionMessagePath { intermediate_nodes, mut destination } = path;
398 if let Destination::BlindedPath(BlindedPath { ref blinded_hops, .. }) = destination {
399 if blinded_hops.is_empty() {
400 return Err(SendError::TooFewBlindedHops);
404 if contents.tlv_type() < 64 { return Err(SendError::InvalidMessage) }
406 // If we are sending straight to a blinded path and we are the introduction node, we need to
407 // advance the blinded path by 1 hop so the second hop is the new introduction node.
408 if intermediate_nodes.len() == 0 {
409 if let Destination::BlindedPath(ref mut blinded_path) = destination {
410 let our_node_id = node_signer.get_node_id(Recipient::Node)
411 .map_err(|()| SendError::GetNodeIdFailed)?;
412 if blinded_path.introduction_node_id == our_node_id {
413 advance_path_by_one(blinded_path, node_signer, &secp_ctx)
414 .map_err(|()| SendError::BlindedPathAdvanceFailed)?;
419 let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
420 let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
421 let (first_node_id, blinding_point) = if let Some(first_node_id) = intermediate_nodes.first() {
422 (*first_node_id, PublicKey::from_secret_key(&secp_ctx, &blinding_secret))
425 Destination::Node(pk) => (pk, PublicKey::from_secret_key(&secp_ctx, &blinding_secret)),
426 Destination::BlindedPath(BlindedPath { introduction_node_id, blinding_point, .. }) =>
427 (introduction_node_id, blinding_point),
430 let (packet_payloads, packet_keys) = packet_payloads_and_keys(
431 &secp_ctx, &intermediate_nodes, destination, contents, reply_path, &blinding_secret)
432 .map_err(|e| SendError::Secp256k1(e))?;
434 let prng_seed = entropy_source.get_secure_random_bytes();
435 let onion_routing_packet = construct_onion_message_packet(
436 packet_payloads, packet_keys, prng_seed).map_err(|()| SendError::TooBigPacket)?;
438 Ok((first_node_id, OnionMessage {
444 /// Decode one layer of an incoming [`OnionMessage`].
446 /// Returns either the next layer of the onion for forwarding or the decrypted content for the
448 pub fn peel_onion_message<NS: Deref, L: Deref, CMH: Deref>(
449 msg: &OnionMessage, secp_ctx: &Secp256k1<secp256k1::All>, node_signer: NS, logger: L,
451 ) -> Result<PeeledOnion<<<CMH>::Target as CustomOnionMessageHandler>::CustomMessage>, ()>
453 NS::Target: NodeSigner,
455 CMH::Target: CustomOnionMessageHandler,
457 let control_tlvs_ss = match node_signer.ecdh(Recipient::Node, &msg.blinding_point, None) {
460 log_error!(logger, "Failed to retrieve node secret: {:?}", e);
464 let onion_decode_ss = {
465 let blinding_factor = {
466 let mut hmac = HmacEngine::<Sha256>::new(b"blinded_node_id");
467 hmac.input(control_tlvs_ss.as_ref());
468 Hmac::from_engine(hmac).to_byte_array()
470 match node_signer.ecdh(Recipient::Node, &msg.onion_routing_packet.public_key,
471 Some(&Scalar::from_be_bytes(blinding_factor).unwrap()))
473 Ok(ss) => ss.secret_bytes(),
475 log_trace!(logger, "Failed to compute onion packet shared secret");
480 match onion_utils::decode_next_untagged_hop(
481 onion_decode_ss, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
482 (control_tlvs_ss, custom_handler.deref(), logger.deref())
484 Ok((Payload::Receive::<ParsedOnionMessageContents<<<CMH as Deref>::Target as CustomOnionMessageHandler>::CustomMessage>> {
485 message, control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id }), reply_path,
487 Ok(PeeledOnion::Receive(message, path_id, reply_path))
489 Ok((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
490 next_node_id, next_blinding_override
491 })), Some((next_hop_hmac, new_packet_bytes)))) => {
492 // TODO: we need to check whether `next_node_id` is our node, in which case this is a dummy
493 // blinded hop and this onion message is destined for us. In this situation, we should keep
494 // unwrapping the onion layers to get to the final payload. Since we don't have the option
495 // of creating blinded paths with dummy hops currently, we should be ok to not handle this
497 let new_pubkey = match onion_utils::next_hop_pubkey(&secp_ctx, msg.onion_routing_packet.public_key, &onion_decode_ss) {
500 log_trace!(logger, "Failed to compute next hop packet pubkey: {}", e);
504 let outgoing_packet = Packet {
506 public_key: new_pubkey,
507 hop_data: new_packet_bytes,
510 let onion_message = OnionMessage {
511 blinding_point: match next_blinding_override {
512 Some(blinding_point) => blinding_point,
514 match onion_utils::next_hop_pubkey(
515 &secp_ctx, msg.blinding_point, control_tlvs_ss.as_ref()
519 log_trace!(logger, "Failed to compute next blinding point: {}", e);
525 onion_routing_packet: outgoing_packet,
528 Ok(PeeledOnion::Forward(next_node_id, onion_message))
531 log_trace!(logger, "Errored decoding onion message packet: {:?}", e);
535 log_trace!(logger, "Received bogus onion message packet, either the sender encoded a final hop as a forwarding hop or vice versa");
541 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref>
542 OnionMessenger<ES, NS, L, MR, OMH, CMH>
544 ES::Target: EntropySource,
545 NS::Target: NodeSigner,
547 MR::Target: MessageRouter,
548 OMH::Target: OffersMessageHandler,
549 CMH::Target: CustomOnionMessageHandler,
551 /// Constructs a new `OnionMessenger` to send, forward, and delegate received onion messages to
552 /// their respective handlers.
554 entropy_source: ES, node_signer: NS, logger: L, message_router: MR, offers_handler: OMH,
557 let mut secp_ctx = Secp256k1::new();
558 secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
562 message_buffers: Mutex::new(HashMap::new()),
571 /// Sends an [`OnionMessage`] with the given `contents` for sending to the destination of
574 /// See [`OnionMessenger`] for example usage.
575 pub fn send_onion_message<T: OnionMessageContents>(
576 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>
577 ) -> Result<(), SendError> {
578 log_trace!(self.logger, "Sending onion message: {:?}", contents);
580 let (first_node_id, onion_message) = create_onion_message(
581 &self.entropy_source, &self.node_signer, &self.secp_ctx, path, contents, reply_path
584 let mut message_buffers = self.message_buffers.lock().unwrap();
585 if outbound_buffer_full(&first_node_id, &message_buffers) {
586 return Err(SendError::BufferFull);
589 match message_buffers.entry(first_node_id) {
590 hash_map::Entry::Vacant(_) => Err(SendError::InvalidFirstHop),
591 hash_map::Entry::Occupied(mut e) => {
592 e.get_mut().enqueue_message(onion_message);
598 fn handle_onion_message_response<T: OnionMessageContents>(
599 &self, response: Option<T>, reply_path: Option<BlindedPath>, log_suffix: fmt::Arguments
601 if let Some(response) = response {
603 Some(reply_path) => {
604 self.find_path_and_enqueue_onion_message(
605 response, Destination::BlindedPath(reply_path), None, log_suffix
609 log_trace!(self.logger, "Missing reply path {}", log_suffix);
615 fn find_path_and_enqueue_onion_message<T: OnionMessageContents>(
616 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>,
617 log_suffix: fmt::Arguments
619 let sender = match self.node_signer.get_node_id(Recipient::Node) {
620 Ok(node_id) => node_id,
622 log_warn!(self.logger, "Unable to retrieve node id {}", log_suffix);
627 let peers = self.message_buffers.lock().unwrap().keys().copied().collect();
628 let path = match self.message_router.find_path(sender, peers, destination) {
631 log_trace!(self.logger, "Failed to find path {}", log_suffix);
636 log_trace!(self.logger, "Sending onion message {}: {:?}", log_suffix, contents);
638 if let Err(e) = self.send_onion_message(path, contents, reply_path) {
639 log_trace!(self.logger, "Failed sending onion message {}: {:?}", log_suffix, e);
644 pub(super) fn release_pending_msgs(&self) -> HashMap<PublicKey, VecDeque<OnionMessage>> {
645 let mut message_buffers = self.message_buffers.lock().unwrap();
646 let mut msgs = HashMap::new();
647 // We don't want to disconnect the peers by removing them entirely from the original map, so we
648 // release the pending message buffers individually.
649 for (peer_node_id, buffer) in &mut *message_buffers {
650 msgs.insert(*peer_node_id, buffer.release_pending_messages());
656 fn outbound_buffer_full(peer_node_id: &PublicKey, buffer: &HashMap<PublicKey, OnionMessageBuffer>) -> bool {
657 const MAX_TOTAL_BUFFER_SIZE: usize = (1 << 20) * 128;
658 const MAX_PER_PEER_BUFFER_SIZE: usize = (1 << 10) * 256;
659 let mut total_buffered_bytes = 0;
660 let mut peer_buffered_bytes = 0;
661 for (pk, peer_buf) in buffer {
662 for om in peer_buf.pending_messages() {
663 let om_len = om.serialized_length();
664 if pk == peer_node_id {
665 peer_buffered_bytes += om_len;
667 total_buffered_bytes += om_len;
669 if total_buffered_bytes >= MAX_TOTAL_BUFFER_SIZE ||
670 peer_buffered_bytes >= MAX_PER_PEER_BUFFER_SIZE
679 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref> OnionMessageHandler
680 for OnionMessenger<ES, NS, L, MR, OMH, CMH>
682 ES::Target: EntropySource,
683 NS::Target: NodeSigner,
685 MR::Target: MessageRouter,
686 OMH::Target: OffersMessageHandler,
687 CMH::Target: CustomOnionMessageHandler,
689 fn handle_onion_message(&self, _peer_node_id: &PublicKey, msg: &OnionMessage) {
690 match peel_onion_message(
691 msg, &self.secp_ctx, &*self.node_signer, &*self.logger, &*self.custom_handler
693 Ok(PeeledOnion::Receive(message, path_id, reply_path)) => {
696 "Received an onion message with path_id {:02x?} and {} reply_path: {:?}",
697 path_id, if reply_path.is_some() { "a" } else { "no" }, message);
700 ParsedOnionMessageContents::Offers(msg) => {
701 let response = self.offers_handler.handle_message(msg);
702 self.handle_onion_message_response(
703 response, reply_path, format_args!(
704 "when responding to Offers onion message with path_id {:02x?}",
709 ParsedOnionMessageContents::Custom(msg) => {
710 let response = self.custom_handler.handle_custom_message(msg);
711 self.handle_onion_message_response(
712 response, reply_path, format_args!(
713 "when responding to Custom onion message with path_id {:02x?}",
720 Ok(PeeledOnion::Forward(next_node_id, onion_message)) => {
721 let mut message_buffers = self.message_buffers.lock().unwrap();
722 if outbound_buffer_full(&next_node_id, &message_buffers) {
723 log_trace!(self.logger, "Dropping forwarded onion message to peer {:?}: outbound buffer full", next_node_id);
730 .or_insert_with(|| OnionMessageBuffer::ConnectedPeer(VecDeque::new()));
732 match message_buffers.entry(next_node_id) {
733 hash_map::Entry::Occupied(mut e) if matches!(
734 e.get(), OnionMessageBuffer::ConnectedPeer(..)
736 e.get_mut().enqueue_message(onion_message);
737 log_trace!(self.logger, "Forwarding an onion message to peer {}", next_node_id);
740 log_trace!(self.logger, "Dropping forwarded onion message to disconnected peer {:?}", next_node_id);
746 log_error!(self.logger, "Failed to process onion message {:?}", e);
751 fn peer_connected(&self, their_node_id: &PublicKey, init: &msgs::Init, _inbound: bool) -> Result<(), ()> {
752 if init.features.supports_onion_messages() {
753 self.message_buffers.lock().unwrap()
754 .entry(*their_node_id)
755 .or_insert_with(|| OnionMessageBuffer::ConnectedPeer(VecDeque::new()))
758 self.message_buffers.lock().unwrap().remove(their_node_id);
764 fn peer_disconnected(&self, their_node_id: &PublicKey) {
765 match self.message_buffers.lock().unwrap().remove(their_node_id) {
766 Some(OnionMessageBuffer::ConnectedPeer(..)) => {},
767 _ => debug_assert!(false),
771 fn provided_node_features(&self) -> NodeFeatures {
772 let mut features = NodeFeatures::empty();
773 features.set_onion_messages_optional();
777 fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
778 let mut features = InitFeatures::empty();
779 features.set_onion_messages_optional();
783 // Before returning any messages to send for the peer, this method will see if any messages were
784 // enqueued in the handler by users, find a path to the corresponding blinded path's introduction
785 // node, and then enqueue the message for sending to the first peer in the full path.
786 fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<OnionMessage> {
787 // Enqueue any initiating `OffersMessage`s to send.
788 for message in self.offers_handler.release_pending_messages() {
789 #[cfg(not(c_bindings))]
790 let PendingOnionMessage { contents, destination, reply_path } = message;
792 let (contents, destination, reply_path) = message;
793 self.find_path_and_enqueue_onion_message(
794 contents, destination, reply_path, format_args!("when sending OffersMessage")
798 // Enqueue any initiating `CustomMessage`s to send.
799 for message in self.custom_handler.release_pending_custom_messages() {
800 #[cfg(not(c_bindings))]
801 let PendingOnionMessage { contents, destination, reply_path } = message;
803 let (contents, destination, reply_path) = message;
804 self.find_path_and_enqueue_onion_message(
805 contents, destination, reply_path, format_args!("when sending CustomMessage")
809 self.message_buffers.lock().unwrap()
810 .get_mut(&peer_node_id)
811 .and_then(|buffer| buffer.dequeue_message())
815 // TODO: parameterize the below Simple* types with OnionMessenger and handle the messages it
817 /// Useful for simplifying the parameters of [`SimpleArcChannelManager`] and
818 /// [`SimpleArcPeerManager`]. See their docs for more details.
820 /// This is not exported to bindings users as type aliases aren't supported in most languages.
822 /// [`SimpleArcChannelManager`]: crate::ln::channelmanager::SimpleArcChannelManager
823 /// [`SimpleArcPeerManager`]: crate::ln::peer_handler::SimpleArcPeerManager
824 #[cfg(not(c_bindings))]
825 pub type SimpleArcOnionMessenger<M, T, F, L> = OnionMessenger<
829 Arc<DefaultMessageRouter>,
830 Arc<SimpleArcChannelManager<M, T, F, L>>,
831 IgnoringMessageHandler
834 /// Useful for simplifying the parameters of [`SimpleRefChannelManager`] and
835 /// [`SimpleRefPeerManager`]. See their docs for more details.
837 /// This is not exported to bindings users as type aliases aren't supported in most languages.
839 /// [`SimpleRefChannelManager`]: crate::ln::channelmanager::SimpleRefChannelManager
840 /// [`SimpleRefPeerManager`]: crate::ln::peer_handler::SimpleRefPeerManager
841 #[cfg(not(c_bindings))]
842 pub type SimpleRefOnionMessenger<
843 'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, 'i, 'j, M, T, F, L
848 &'i DefaultMessageRouter,
849 &'j SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, M, T, F, L>,
850 IgnoringMessageHandler
853 /// Construct onion packet payloads and keys for sending an onion message along the given
854 /// `unblinded_path` to the given `destination`.
855 fn packet_payloads_and_keys<T: OnionMessageContents, S: secp256k1::Signing + secp256k1::Verification>(
856 secp_ctx: &Secp256k1<S>, unblinded_path: &[PublicKey], destination: Destination, message: T,
857 mut reply_path: Option<BlindedPath>, session_priv: &SecretKey
858 ) -> Result<(Vec<(Payload<T>, [u8; 32])>, Vec<onion_utils::OnionKeys>), secp256k1::Error> {
859 let num_hops = unblinded_path.len() + destination.num_hops();
860 let mut payloads = Vec::with_capacity(num_hops);
861 let mut onion_packet_keys = Vec::with_capacity(num_hops);
863 let (mut intro_node_id_blinding_pt, num_blinded_hops) = if let Destination::BlindedPath(BlindedPath {
864 introduction_node_id, blinding_point, blinded_hops }) = &destination {
865 (Some((*introduction_node_id, *blinding_point)), blinded_hops.len()) } else { (None, 0) };
866 let num_unblinded_hops = num_hops - num_blinded_hops;
868 let mut unblinded_path_idx = 0;
869 let mut blinded_path_idx = 0;
870 let mut prev_control_tlvs_ss = None;
871 let mut final_control_tlvs = None;
872 utils::construct_keys_callback(secp_ctx, unblinded_path.iter(), Some(destination), session_priv,
873 |_, onion_packet_ss, ephemeral_pubkey, control_tlvs_ss, unblinded_pk_opt, enc_payload_opt| {
874 if num_unblinded_hops != 0 && unblinded_path_idx < num_unblinded_hops {
875 if let Some(ss) = prev_control_tlvs_ss.take() {
876 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(
878 next_node_id: unblinded_pk_opt.unwrap(),
879 next_blinding_override: None,
883 prev_control_tlvs_ss = Some(control_tlvs_ss);
884 unblinded_path_idx += 1;
885 } else if let Some((intro_node_id, blinding_pt)) = intro_node_id_blinding_pt.take() {
886 if let Some(control_tlvs_ss) = prev_control_tlvs_ss.take() {
887 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
888 next_node_id: intro_node_id,
889 next_blinding_override: Some(blinding_pt),
890 })), control_tlvs_ss));
893 if blinded_path_idx < num_blinded_hops.saturating_sub(1) && enc_payload_opt.is_some() {
894 payloads.push((Payload::Forward(ForwardControlTlvs::Blinded(enc_payload_opt.unwrap())),
896 blinded_path_idx += 1;
897 } else if let Some(encrypted_payload) = enc_payload_opt {
898 final_control_tlvs = Some(ReceiveControlTlvs::Blinded(encrypted_payload));
899 prev_control_tlvs_ss = Some(control_tlvs_ss);
902 let (rho, mu) = onion_utils::gen_rho_mu_from_shared_secret(onion_packet_ss.as_ref());
903 onion_packet_keys.push(onion_utils::OnionKeys {
905 shared_secret: onion_packet_ss,
907 blinding_factor: [0; 32],
915 if let Some(control_tlvs) = final_control_tlvs {
916 payloads.push((Payload::Receive {
918 reply_path: reply_path.take(),
920 }, prev_control_tlvs_ss.unwrap()));
922 payloads.push((Payload::Receive {
923 control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id: None, }),
924 reply_path: reply_path.take(),
926 }, prev_control_tlvs_ss.unwrap()));
929 Ok((payloads, onion_packet_keys))
932 /// Errors if the serialized payload size exceeds onion_message::BIG_PACKET_HOP_DATA_LEN
933 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, ()> {
935 // "`len` allows larger messages to be sent than the standard 1300 bytes allowed for an HTLC
936 // onion, but this should be used sparingly as it is reduces anonymity set, hence the
937 // recommendation that it either look like an HTLC onion, or if larger, be a fixed size."
938 let payloads_ser_len = onion_utils::payloads_serialized_length(&payloads);
939 let hop_data_len = if payloads_ser_len <= SMALL_PACKET_HOP_DATA_LEN {
940 SMALL_PACKET_HOP_DATA_LEN
941 } else if payloads_ser_len <= BIG_PACKET_HOP_DATA_LEN {
942 BIG_PACKET_HOP_DATA_LEN
943 } else { return Err(()) };
945 onion_utils::construct_onion_message_packet::<_, _>(
946 payloads, onion_keys, prng_seed, hop_data_len)