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 pending_messages: Mutex<HashMap<PublicKey, VecDeque<OnionMessage>>>,
154 secp_ctx: Secp256k1<secp256k1::All>,
160 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
162 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
163 /// enqueued for sending.
164 #[cfg(not(c_bindings))]
165 pub struct PendingOnionMessage<T: OnionMessageContents> {
166 /// The message contents to send in an [`OnionMessage`].
169 /// The destination of the message.
170 pub destination: Destination,
172 /// A reply path to include in the [`OnionMessage`] for a response.
173 pub reply_path: Option<BlindedPath>,
177 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
179 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
180 /// enqueued for sending.
181 pub type PendingOnionMessage<T: OnionMessageContents> = (T, Destination, Option<BlindedPath>);
183 pub(crate) fn new_pending_onion_message<T: OnionMessageContents>(
184 contents: T, destination: Destination, reply_path: Option<BlindedPath>
185 ) -> PendingOnionMessage<T> {
186 #[cfg(not(c_bindings))]
187 return PendingOnionMessage { contents, destination, reply_path };
189 return (contents, destination, reply_path);
192 /// A trait defining behavior for routing an [`OnionMessage`].
193 pub trait MessageRouter {
194 /// Returns a route for sending an [`OnionMessage`] to the given [`Destination`].
196 &self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
197 ) -> Result<OnionMessagePath, ()>;
200 /// A [`MessageRouter`] that can only route to a directly connected [`Destination`].
201 pub struct DefaultMessageRouter;
203 impl MessageRouter for DefaultMessageRouter {
205 &self, _sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
206 ) -> Result<OnionMessagePath, ()> {
207 if peers.contains(&destination.first_node()) {
208 Ok(OnionMessagePath { intermediate_nodes: vec![], destination })
215 /// A path for sending an [`OnionMessage`].
217 pub struct OnionMessagePath {
218 /// Nodes on the path between the sender and the destination.
219 pub intermediate_nodes: Vec<PublicKey>,
221 /// The recipient of the message.
222 pub destination: Destination,
225 /// The destination of an onion message.
227 pub enum Destination {
228 /// We're sending this onion message to a node.
230 /// We're sending this onion message to a blinded path.
231 BlindedPath(BlindedPath),
235 pub(super) fn num_hops(&self) -> usize {
237 Destination::Node(_) => 1,
238 Destination::BlindedPath(BlindedPath { blinded_hops, .. }) => blinded_hops.len(),
242 fn first_node(&self) -> PublicKey {
244 Destination::Node(node_id) => *node_id,
245 Destination::BlindedPath(BlindedPath { introduction_node_id: node_id, .. }) => *node_id,
250 /// Errors that may occur when [sending an onion message].
252 /// [sending an onion message]: OnionMessenger::send_onion_message
253 #[derive(Debug, PartialEq, Eq)]
255 /// Errored computing onion message packet keys.
256 Secp256k1(secp256k1::Error),
257 /// Because implementations such as Eclair will drop onion messages where the message packet
258 /// exceeds 32834 bytes, we refuse to send messages where the packet exceeds this size.
260 /// The provided [`Destination`] was an invalid [`BlindedPath`] due to not having any blinded
263 /// Our next-hop peer was offline or does not support onion message forwarding.
265 /// Onion message contents must have a TLV type >= 64.
267 /// Our next-hop peer's buffer was full or our total outbound buffer was full.
269 /// Failed to retrieve our node id from the provided [`NodeSigner`].
271 /// [`NodeSigner`]: crate::sign::NodeSigner
273 /// We attempted to send to a blinded path where we are the introduction node, and failed to
274 /// advance the blinded path to make the second hop the new introduction node. Either
275 /// [`NodeSigner::ecdh`] failed, we failed to tweak the current blinding point to get the
276 /// new blinding point, or we were attempting to send to ourselves.
277 BlindedPathAdvanceFailed,
280 /// Handler for custom onion messages. If you are using [`SimpleArcOnionMessenger`],
281 /// [`SimpleRefOnionMessenger`], or prefer to ignore inbound custom onion messages,
282 /// [`IgnoringMessageHandler`] must be provided to [`OnionMessenger::new`]. Otherwise, a custom
283 /// implementation of this trait must be provided, with [`CustomMessage`] specifying the supported
286 /// See [`OnionMessenger`] for example usage.
288 /// [`IgnoringMessageHandler`]: crate::ln::peer_handler::IgnoringMessageHandler
289 /// [`CustomMessage`]: Self::CustomMessage
290 pub trait CustomOnionMessageHandler {
291 /// The message known to the handler. To support multiple message types, you may want to make this
292 /// an enum with a variant for each supported message.
293 type CustomMessage: OnionMessageContents;
295 /// Called with the custom message that was received, returning a response to send, if any.
297 /// The returned [`Self::CustomMessage`], if any, is enqueued to be sent by [`OnionMessenger`].
298 fn handle_custom_message(&self, msg: Self::CustomMessage) -> Option<Self::CustomMessage>;
300 /// Read a custom message of type `message_type` from `buffer`, returning `Ok(None)` if the
301 /// message type is unknown.
302 fn read_custom_message<R: io::Read>(&self, message_type: u64, buffer: &mut R) -> Result<Option<Self::CustomMessage>, msgs::DecodeError>;
304 /// Releases any [`Self::CustomMessage`]s that need to be sent.
306 /// Typically, this is used for messages initiating a message flow rather than in response to
307 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
308 #[cfg(not(c_bindings))]
309 fn release_pending_custom_messages(&self) -> Vec<PendingOnionMessage<Self::CustomMessage>>;
311 /// Releases any [`Self::CustomMessage`]s that need to be sent.
313 /// Typically, this is used for messages initiating a message flow rather than in response to
314 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
316 fn release_pending_custom_messages(&self) -> Vec<(Self::CustomMessage, Destination, Option<BlindedPath>)>;
319 /// A processed incoming onion message, containing either a Forward (another onion message)
320 /// or a Receive payload with decrypted contents.
321 pub enum PeeledOnion<T: OnionMessageContents> {
322 /// Forwarded onion, with the next node id and a new onion
323 Forward(PublicKey, OnionMessage),
324 /// Received onion message, with decrypted contents, path_id, and reply path
325 Receive(ParsedOnionMessageContents<T>, Option<[u8; 32]>, Option<BlindedPath>)
328 /// Creates an [`OnionMessage`] with the given `contents` for sending to the destination of
331 /// Returns both the node id of the peer to send the message to and the message itself.
332 pub fn create_onion_message<ES: Deref, NS: Deref, T: OnionMessageContents>(
333 entropy_source: &ES, node_signer: &NS, secp_ctx: &Secp256k1<secp256k1::All>,
334 path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
335 ) -> Result<(PublicKey, OnionMessage), SendError>
337 ES::Target: EntropySource,
338 NS::Target: NodeSigner,
340 let OnionMessagePath { intermediate_nodes, mut destination } = path;
341 if let Destination::BlindedPath(BlindedPath { ref blinded_hops, .. }) = destination {
342 if blinded_hops.is_empty() {
343 return Err(SendError::TooFewBlindedHops);
347 if contents.tlv_type() < 64 { return Err(SendError::InvalidMessage) }
349 // If we are sending straight to a blinded path and we are the introduction node, we need to
350 // advance the blinded path by 1 hop so the second hop is the new introduction node.
351 if intermediate_nodes.len() == 0 {
352 if let Destination::BlindedPath(ref mut blinded_path) = destination {
353 let our_node_id = node_signer.get_node_id(Recipient::Node)
354 .map_err(|()| SendError::GetNodeIdFailed)?;
355 if blinded_path.introduction_node_id == our_node_id {
356 advance_path_by_one(blinded_path, node_signer, &secp_ctx)
357 .map_err(|()| SendError::BlindedPathAdvanceFailed)?;
362 let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
363 let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
364 let (first_node_id, blinding_point) = if let Some(first_node_id) = intermediate_nodes.first() {
365 (*first_node_id, PublicKey::from_secret_key(&secp_ctx, &blinding_secret))
368 Destination::Node(pk) => (pk, PublicKey::from_secret_key(&secp_ctx, &blinding_secret)),
369 Destination::BlindedPath(BlindedPath { introduction_node_id, blinding_point, .. }) =>
370 (introduction_node_id, blinding_point),
373 let (packet_payloads, packet_keys) = packet_payloads_and_keys(
374 &secp_ctx, &intermediate_nodes, destination, contents, reply_path, &blinding_secret)
375 .map_err(|e| SendError::Secp256k1(e))?;
377 let prng_seed = entropy_source.get_secure_random_bytes();
378 let onion_routing_packet = construct_onion_message_packet(
379 packet_payloads, packet_keys, prng_seed).map_err(|()| SendError::TooBigPacket)?;
381 Ok((first_node_id, OnionMessage {
387 /// Decode one layer of an incoming [`OnionMessage`].
389 /// Returns either the next layer of the onion for forwarding or the decrypted content for the
391 pub fn peel_onion_message<NS: Deref, L: Deref, CMH: Deref>(
392 msg: &OnionMessage, secp_ctx: &Secp256k1<secp256k1::All>, node_signer: NS, logger: L,
394 ) -> Result<PeeledOnion<<<CMH>::Target as CustomOnionMessageHandler>::CustomMessage>, ()>
396 NS::Target: NodeSigner,
398 CMH::Target: CustomOnionMessageHandler,
400 let control_tlvs_ss = match node_signer.ecdh(Recipient::Node, &msg.blinding_point, None) {
403 log_error!(logger, "Failed to retrieve node secret: {:?}", e);
407 let onion_decode_ss = {
408 let blinding_factor = {
409 let mut hmac = HmacEngine::<Sha256>::new(b"blinded_node_id");
410 hmac.input(control_tlvs_ss.as_ref());
411 Hmac::from_engine(hmac).to_byte_array()
413 match node_signer.ecdh(Recipient::Node, &msg.onion_routing_packet.public_key,
414 Some(&Scalar::from_be_bytes(blinding_factor).unwrap()))
416 Ok(ss) => ss.secret_bytes(),
418 log_trace!(logger, "Failed to compute onion packet shared secret");
423 match onion_utils::decode_next_untagged_hop(
424 onion_decode_ss, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
425 (control_tlvs_ss, custom_handler.deref(), logger.deref())
427 Ok((Payload::Receive::<ParsedOnionMessageContents<<<CMH as Deref>::Target as CustomOnionMessageHandler>::CustomMessage>> {
428 message, control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id }), reply_path,
430 Ok(PeeledOnion::Receive(message, path_id, reply_path))
432 Ok((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
433 next_node_id, next_blinding_override
434 })), Some((next_hop_hmac, new_packet_bytes)))) => {
435 // TODO: we need to check whether `next_node_id` is our node, in which case this is a dummy
436 // blinded hop and this onion message is destined for us. In this situation, we should keep
437 // unwrapping the onion layers to get to the final payload. Since we don't have the option
438 // of creating blinded paths with dummy hops currently, we should be ok to not handle this
440 let new_pubkey = match onion_utils::next_hop_pubkey(&secp_ctx, msg.onion_routing_packet.public_key, &onion_decode_ss) {
443 log_trace!(logger, "Failed to compute next hop packet pubkey: {}", e);
447 let outgoing_packet = Packet {
449 public_key: new_pubkey,
450 hop_data: new_packet_bytes,
453 let onion_message = OnionMessage {
454 blinding_point: match next_blinding_override {
455 Some(blinding_point) => blinding_point,
457 match onion_utils::next_hop_pubkey(
458 &secp_ctx, msg.blinding_point, control_tlvs_ss.as_ref()
462 log_trace!(logger, "Failed to compute next blinding point: {}", e);
468 onion_routing_packet: outgoing_packet,
471 Ok(PeeledOnion::Forward(next_node_id, onion_message))
474 log_trace!(logger, "Errored decoding onion message packet: {:?}", e);
478 log_trace!(logger, "Received bogus onion message packet, either the sender encoded a final hop as a forwarding hop or vice versa");
484 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref>
485 OnionMessenger<ES, NS, L, MR, OMH, CMH>
487 ES::Target: EntropySource,
488 NS::Target: NodeSigner,
490 MR::Target: MessageRouter,
491 OMH::Target: OffersMessageHandler,
492 CMH::Target: CustomOnionMessageHandler,
494 /// Constructs a new `OnionMessenger` to send, forward, and delegate received onion messages to
495 /// their respective handlers.
497 entropy_source: ES, node_signer: NS, logger: L, message_router: MR, offers_handler: OMH,
500 let mut secp_ctx = Secp256k1::new();
501 secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
505 pending_messages: Mutex::new(HashMap::new()),
514 /// Sends an [`OnionMessage`] with the given `contents` for sending to the destination of
517 /// See [`OnionMessenger`] for example usage.
518 pub fn send_onion_message<T: OnionMessageContents>(
519 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>
520 ) -> Result<(), SendError> {
522 log_trace!(self.logger, "Sending onion message: {:?}", contents);
524 let (first_node_id, onion_msg) = create_onion_message(
525 &self.entropy_source, &self.node_signer, &self.secp_ctx, path, contents, reply_path
528 let mut pending_per_peer_msgs = self.pending_messages.lock().unwrap();
529 if outbound_buffer_full(&first_node_id, &pending_per_peer_msgs) { return Err(SendError::BufferFull) }
530 match pending_per_peer_msgs.entry(first_node_id) {
531 hash_map::Entry::Vacant(_) => Err(SendError::InvalidFirstHop),
532 hash_map::Entry::Occupied(mut e) => {
533 e.get_mut().push_back(onion_msg);
539 fn handle_onion_message_response<T: OnionMessageContents>(
540 &self, response: Option<T>, reply_path: Option<BlindedPath>, log_suffix: fmt::Arguments
542 if let Some(response) = response {
544 Some(reply_path) => {
545 self.find_path_and_enqueue_onion_message(
546 response, Destination::BlindedPath(reply_path), None, log_suffix
550 log_trace!(self.logger, "Missing reply path {}", log_suffix);
556 fn find_path_and_enqueue_onion_message<T: OnionMessageContents>(
557 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>,
558 log_suffix: fmt::Arguments
560 let sender = match self.node_signer.get_node_id(Recipient::Node) {
561 Ok(node_id) => node_id,
563 log_warn!(self.logger, "Unable to retrieve node id {}", log_suffix);
568 let peers = self.pending_messages.lock().unwrap().keys().copied().collect();
569 let path = match self.message_router.find_path(sender, peers, destination) {
572 log_trace!(self.logger, "Failed to find path {}", log_suffix);
577 log_trace!(self.logger, "Sending onion message {}: {:?}", log_suffix, contents);
579 if let Err(e) = self.send_onion_message(path, contents, reply_path) {
580 log_trace!(self.logger, "Failed sending onion message {}: {:?}", log_suffix, e);
586 pub(super) fn release_pending_msgs(&self) -> HashMap<PublicKey, VecDeque<OnionMessage>> {
587 let mut pending_msgs = self.pending_messages.lock().unwrap();
588 let mut msgs = HashMap::new();
589 // We don't want to disconnect the peers by removing them entirely from the original map, so we
590 // swap the pending message buffers individually.
591 for (peer_node_id, pending_messages) in &mut *pending_msgs {
592 msgs.insert(*peer_node_id, core::mem::take(pending_messages));
598 fn outbound_buffer_full(peer_node_id: &PublicKey, buffer: &HashMap<PublicKey, VecDeque<OnionMessage>>) -> bool {
599 const MAX_TOTAL_BUFFER_SIZE: usize = (1 << 20) * 128;
600 const MAX_PER_PEER_BUFFER_SIZE: usize = (1 << 10) * 256;
601 let mut total_buffered_bytes = 0;
602 let mut peer_buffered_bytes = 0;
603 for (pk, peer_buf) in buffer {
605 let om_len = om.serialized_length();
606 if pk == peer_node_id {
607 peer_buffered_bytes += om_len;
609 total_buffered_bytes += om_len;
611 if total_buffered_bytes >= MAX_TOTAL_BUFFER_SIZE ||
612 peer_buffered_bytes >= MAX_PER_PEER_BUFFER_SIZE
621 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref> OnionMessageHandler
622 for OnionMessenger<ES, NS, L, MR, OMH, CMH>
624 ES::Target: EntropySource,
625 NS::Target: NodeSigner,
627 MR::Target: MessageRouter,
628 OMH::Target: OffersMessageHandler,
629 CMH::Target: CustomOnionMessageHandler,
631 fn handle_onion_message(&self, _peer_node_id: &PublicKey, msg: &OnionMessage) {
632 match peel_onion_message(
633 msg, &self.secp_ctx, &*self.node_signer, &*self.logger, &*self.custom_handler
635 Ok(PeeledOnion::Receive(message, path_id, reply_path)) => {
638 "Received an onion message with path_id {:02x?} and {} reply_path: {:?}",
639 path_id, if reply_path.is_some() { "a" } else { "no" }, message);
642 ParsedOnionMessageContents::Offers(msg) => {
643 let response = self.offers_handler.handle_message(msg);
644 self.handle_onion_message_response(
645 response, reply_path, format_args!(
646 "when responding to Offers onion message with path_id {:02x?}",
651 ParsedOnionMessageContents::Custom(msg) => {
652 let response = self.custom_handler.handle_custom_message(msg);
653 self.handle_onion_message_response(
654 response, reply_path, format_args!(
655 "when responding to Custom onion message with path_id {:02x?}",
662 Ok(PeeledOnion::Forward(next_node_id, onion_message)) => {
663 let mut pending_per_peer_msgs = self.pending_messages.lock().unwrap();
664 if outbound_buffer_full(&next_node_id, &pending_per_peer_msgs) {
665 log_trace!(self.logger, "Dropping forwarded onion message to peer {:?}: outbound buffer full", next_node_id);
670 pending_per_peer_msgs.entry(next_node_id).or_insert_with(VecDeque::new);
672 match pending_per_peer_msgs.entry(next_node_id) {
673 hash_map::Entry::Vacant(_) => {
674 log_trace!(self.logger, "Dropping forwarded onion message to disconnected peer {:?}", next_node_id);
677 hash_map::Entry::Occupied(mut e) => {
678 e.get_mut().push_back(onion_message);
679 log_trace!(self.logger, "Forwarding an onion message to peer {}", next_node_id);
684 log_error!(self.logger, "Failed to process onion message {:?}", e);
689 fn peer_connected(&self, their_node_id: &PublicKey, init: &msgs::Init, _inbound: bool) -> Result<(), ()> {
690 if init.features.supports_onion_messages() {
691 let mut peers = self.pending_messages.lock().unwrap();
692 peers.insert(their_node_id.clone(), VecDeque::new());
697 fn peer_disconnected(&self, their_node_id: &PublicKey) {
698 let mut pending_msgs = self.pending_messages.lock().unwrap();
699 pending_msgs.remove(their_node_id);
702 fn provided_node_features(&self) -> NodeFeatures {
703 let mut features = NodeFeatures::empty();
704 features.set_onion_messages_optional();
708 fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
709 let mut features = InitFeatures::empty();
710 features.set_onion_messages_optional();
714 // Before returning any messages to send for the peer, this method will see if any messages were
715 // enqueued in the handler by users, find a path to the corresponding blinded path's introduction
716 // node, and then enqueue the message for sending to the first peer in the full path.
717 fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<OnionMessage> {
718 // Enqueue any initiating `OffersMessage`s to send.
719 for message in self.offers_handler.release_pending_messages() {
720 #[cfg(not(c_bindings))]
721 let PendingOnionMessage { contents, destination, reply_path } = message;
723 let (contents, destination, reply_path) = message;
724 self.find_path_and_enqueue_onion_message(
725 contents, destination, reply_path, format_args!("when sending OffersMessage")
729 // Enqueue any initiating `CustomMessage`s to send.
730 for message in self.custom_handler.release_pending_custom_messages() {
731 #[cfg(not(c_bindings))]
732 let PendingOnionMessage { contents, destination, reply_path } = message;
734 let (contents, destination, reply_path) = message;
735 self.find_path_and_enqueue_onion_message(
736 contents, destination, reply_path, format_args!("when sending CustomMessage")
740 let mut pending_msgs = self.pending_messages.lock().unwrap();
741 if let Some(msgs) = pending_msgs.get_mut(&peer_node_id) {
742 return msgs.pop_front()
748 // TODO: parameterize the below Simple* types with OnionMessenger and handle the messages it
750 /// Useful for simplifying the parameters of [`SimpleArcChannelManager`] and
751 /// [`SimpleArcPeerManager`]. See their docs for more details.
753 /// This is not exported to bindings users as type aliases aren't supported in most languages.
755 /// [`SimpleArcChannelManager`]: crate::ln::channelmanager::SimpleArcChannelManager
756 /// [`SimpleArcPeerManager`]: crate::ln::peer_handler::SimpleArcPeerManager
757 #[cfg(not(c_bindings))]
758 pub type SimpleArcOnionMessenger<M, T, F, L> = OnionMessenger<
762 Arc<DefaultMessageRouter>,
763 Arc<SimpleArcChannelManager<M, T, F, L>>,
764 IgnoringMessageHandler
767 /// Useful for simplifying the parameters of [`SimpleRefChannelManager`] and
768 /// [`SimpleRefPeerManager`]. See their docs for more details.
770 /// This is not exported to bindings users as type aliases aren't supported in most languages.
772 /// [`SimpleRefChannelManager`]: crate::ln::channelmanager::SimpleRefChannelManager
773 /// [`SimpleRefPeerManager`]: crate::ln::peer_handler::SimpleRefPeerManager
774 #[cfg(not(c_bindings))]
775 pub type SimpleRefOnionMessenger<
776 'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, 'i, 'j, M, T, F, L
781 &'i DefaultMessageRouter,
782 &'j SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, M, T, F, L>,
783 IgnoringMessageHandler
786 /// Construct onion packet payloads and keys for sending an onion message along the given
787 /// `unblinded_path` to the given `destination`.
788 fn packet_payloads_and_keys<T: OnionMessageContents, S: secp256k1::Signing + secp256k1::Verification>(
789 secp_ctx: &Secp256k1<S>, unblinded_path: &[PublicKey], destination: Destination, message: T,
790 mut reply_path: Option<BlindedPath>, session_priv: &SecretKey
791 ) -> Result<(Vec<(Payload<T>, [u8; 32])>, Vec<onion_utils::OnionKeys>), secp256k1::Error> {
792 let num_hops = unblinded_path.len() + destination.num_hops();
793 let mut payloads = Vec::with_capacity(num_hops);
794 let mut onion_packet_keys = Vec::with_capacity(num_hops);
796 let (mut intro_node_id_blinding_pt, num_blinded_hops) = if let Destination::BlindedPath(BlindedPath {
797 introduction_node_id, blinding_point, blinded_hops }) = &destination {
798 (Some((*introduction_node_id, *blinding_point)), blinded_hops.len()) } else { (None, 0) };
799 let num_unblinded_hops = num_hops - num_blinded_hops;
801 let mut unblinded_path_idx = 0;
802 let mut blinded_path_idx = 0;
803 let mut prev_control_tlvs_ss = None;
804 let mut final_control_tlvs = None;
805 utils::construct_keys_callback(secp_ctx, unblinded_path.iter(), Some(destination), session_priv,
806 |_, onion_packet_ss, ephemeral_pubkey, control_tlvs_ss, unblinded_pk_opt, enc_payload_opt| {
807 if num_unblinded_hops != 0 && unblinded_path_idx < num_unblinded_hops {
808 if let Some(ss) = prev_control_tlvs_ss.take() {
809 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(
811 next_node_id: unblinded_pk_opt.unwrap(),
812 next_blinding_override: None,
816 prev_control_tlvs_ss = Some(control_tlvs_ss);
817 unblinded_path_idx += 1;
818 } else if let Some((intro_node_id, blinding_pt)) = intro_node_id_blinding_pt.take() {
819 if let Some(control_tlvs_ss) = prev_control_tlvs_ss.take() {
820 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
821 next_node_id: intro_node_id,
822 next_blinding_override: Some(blinding_pt),
823 })), control_tlvs_ss));
826 if blinded_path_idx < num_blinded_hops.saturating_sub(1) && enc_payload_opt.is_some() {
827 payloads.push((Payload::Forward(ForwardControlTlvs::Blinded(enc_payload_opt.unwrap())),
829 blinded_path_idx += 1;
830 } else if let Some(encrypted_payload) = enc_payload_opt {
831 final_control_tlvs = Some(ReceiveControlTlvs::Blinded(encrypted_payload));
832 prev_control_tlvs_ss = Some(control_tlvs_ss);
835 let (rho, mu) = onion_utils::gen_rho_mu_from_shared_secret(onion_packet_ss.as_ref());
836 onion_packet_keys.push(onion_utils::OnionKeys {
838 shared_secret: onion_packet_ss,
840 blinding_factor: [0; 32],
848 if let Some(control_tlvs) = final_control_tlvs {
849 payloads.push((Payload::Receive {
851 reply_path: reply_path.take(),
853 }, prev_control_tlvs_ss.unwrap()));
855 payloads.push((Payload::Receive {
856 control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id: None, }),
857 reply_path: reply_path.take(),
859 }, prev_control_tlvs_ss.unwrap()));
862 Ok((payloads, onion_packet_keys))
865 /// Errors if the serialized payload size exceeds onion_message::BIG_PACKET_HOP_DATA_LEN
866 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, ()> {
868 // "`len` allows larger messages to be sent than the standard 1300 bytes allowed for an HTLC
869 // onion, but this should be used sparingly as it is reduces anonymity set, hence the
870 // recommendation that it either look like an HTLC onion, or if larger, be a fixed size."
871 let payloads_ser_len = onion_utils::payloads_serialized_length(&payloads);
872 let hop_data_len = if payloads_ser_len <= SMALL_PACKET_HOP_DATA_LEN {
873 SMALL_PACKET_HOP_DATA_LEN
874 } else if payloads_ser_len <= BIG_PACKET_HOP_DATA_LEN {
875 BIG_PACKET_HOP_DATA_LEN
876 } else { return Err(()) };
878 onion_utils::construct_onion_message_packet::<_, _>(
879 payloads, onion_keys, prng_seed, hop_data_len)