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 use crate::ln::features::{InitFeatures, NodeFeatures};
23 use crate::ln::msgs::{self, OnionMessageHandler};
24 use crate::ln::onion_utils;
25 use crate::ln::peer_handler::IgnoringMessageHandler;
26 pub use super::packet::{CustomOnionMessageContents, OnionMessageContents};
27 use super::offers::OffersMessageHandler;
28 use super::packet::{BIG_PACKET_HOP_DATA_LEN, ForwardControlTlvs, Packet, Payload, ReceiveControlTlvs, SMALL_PACKET_HOP_DATA_LEN};
29 use crate::util::logger::Logger;
30 use crate::util::ser::Writeable;
34 use crate::sync::{Arc, Mutex};
35 use crate::prelude::*;
37 /// A sender, receiver and forwarder of [`OnionMessage`]s.
39 /// # Handling Messages
41 /// `OnionMessenger` implements [`OnionMessageHandler`], making it responsible for either forwarding
42 /// messages to peers or delegating to the appropriate handler for the message type. Currently, the
43 /// available handlers are:
44 /// * [`OffersMessageHandler`], for responding to [`InvoiceRequest`]s and paying [`Bolt12Invoice`]s
45 /// * [`CustomOnionMessageHandler`], for handling user-defined message types
47 /// # Sending Messages
49 /// [`OnionMessage`]s are sent initially using [`OnionMessenger::send_onion_message`]. When handling
50 /// a message, the matched handler may return a response message which `OnionMessenger` will send
56 /// # extern crate bitcoin;
57 /// # use bitcoin::hashes::_export::_core::time::Duration;
58 /// # use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey};
59 /// # use lightning::blinded_path::BlindedPath;
60 /// # use lightning::sign::KeysManager;
61 /// # use lightning::ln::peer_handler::IgnoringMessageHandler;
62 /// # use lightning::onion_message::{CustomOnionMessageContents, Destination, MessageRouter, OnionMessageContents, OnionMessagePath, OnionMessenger};
63 /// # use lightning::util::logger::{Logger, Record};
64 /// # use lightning::util::ser::{Writeable, Writer};
65 /// # use lightning::io;
66 /// # use std::sync::Arc;
67 /// # struct FakeLogger;
68 /// # impl Logger for FakeLogger {
69 /// # fn log(&self, record: &Record) { unimplemented!() }
71 /// # struct FakeMessageRouter {}
72 /// # impl MessageRouter for FakeMessageRouter {
73 /// # fn find_path(&self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination) -> Result<OnionMessagePath, ()> {
74 /// # unimplemented!()
77 /// # let seed = [42u8; 32];
78 /// # let time = Duration::from_secs(123456);
79 /// # let keys_manager = KeysManager::new(&seed, time.as_secs(), time.subsec_nanos());
80 /// # let logger = Arc::new(FakeLogger {});
81 /// # let node_secret = SecretKey::from_slice(&hex::decode("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
82 /// # let secp_ctx = Secp256k1::new();
83 /// # let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
84 /// # let (hop_node_id2, hop_node_id3, hop_node_id4) = (hop_node_id1, hop_node_id1, hop_node_id1);
85 /// # let destination_node_id = hop_node_id1;
86 /// # let message_router = Arc::new(FakeMessageRouter {});
87 /// # let custom_message_handler = IgnoringMessageHandler {};
88 /// # let offers_message_handler = IgnoringMessageHandler {};
89 /// // Create the onion messenger. This must use the same `keys_manager` as is passed to your
90 /// // ChannelManager.
91 /// let onion_messenger = OnionMessenger::new(
92 /// &keys_manager, &keys_manager, logger, message_router, &offers_message_handler,
93 /// &custom_message_handler
96 /// # struct YourCustomMessage {}
97 /// impl Writeable for YourCustomMessage {
98 /// fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
100 /// // Write your custom onion message to `w`
103 /// impl CustomOnionMessageContents for YourCustomMessage {
104 /// fn tlv_type(&self) -> u64 {
105 /// # let your_custom_message_type = 42;
106 /// your_custom_message_type
109 /// // Send a custom onion message to a node id.
110 /// let path = OnionMessagePath {
111 /// intermediate_nodes: vec![hop_node_id1, hop_node_id2],
112 /// destination: Destination::Node(destination_node_id),
114 /// let reply_path = None;
115 /// # let your_custom_message = YourCustomMessage {};
116 /// let message = OnionMessageContents::Custom(your_custom_message);
117 /// onion_messenger.send_onion_message(path, message, reply_path);
119 /// // Create a blinded path to yourself, for someone to send an onion message to.
120 /// # let your_node_id = hop_node_id1;
121 /// let hops = [hop_node_id3, hop_node_id4, your_node_id];
122 /// let blinded_path = BlindedPath::new_for_message(&hops, &keys_manager, &secp_ctx).unwrap();
124 /// // Send a custom onion message to a blinded path.
125 /// let path = OnionMessagePath {
126 /// intermediate_nodes: vec![hop_node_id1, hop_node_id2],
127 /// destination: Destination::BlindedPath(blinded_path),
129 /// let reply_path = None;
130 /// # let your_custom_message = YourCustomMessage {};
131 /// let message = OnionMessageContents::Custom(your_custom_message);
132 /// onion_messenger.send_onion_message(path, message, reply_path);
135 /// [`OnionMessage`]: crate::ln::msgs::OnionMessage
136 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
137 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
138 pub struct OnionMessenger<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref>
140 ES::Target: EntropySource,
141 NS::Target: NodeSigner,
143 MR::Target: MessageRouter,
144 OMH::Target: OffersMessageHandler,
145 CMH:: Target: CustomOnionMessageHandler,
150 pending_messages: Mutex<HashMap<PublicKey, VecDeque<msgs::OnionMessage>>>,
151 secp_ctx: Secp256k1<secp256k1::All>,
157 /// A trait defining behavior for routing an [`OnionMessage`].
159 /// [`OnionMessage`]: msgs::OnionMessage
160 pub trait MessageRouter {
161 /// Returns a route for sending an [`OnionMessage`] to the given [`Destination`].
163 /// [`OnionMessage`]: msgs::OnionMessage
165 &self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
166 ) -> Result<OnionMessagePath, ()>;
169 /// A [`MessageRouter`] that always fails.
170 pub struct DefaultMessageRouter;
172 impl MessageRouter for DefaultMessageRouter {
174 &self, _sender: PublicKey, _peers: Vec<PublicKey>, _destination: Destination
175 ) -> Result<OnionMessagePath, ()> {
180 /// A path for sending an [`msgs::OnionMessage`].
182 pub struct OnionMessagePath {
183 /// Nodes on the path between the sender and the destination.
184 pub intermediate_nodes: Vec<PublicKey>,
186 /// The recipient of the message.
187 pub destination: Destination,
190 /// The destination of an onion message.
192 pub enum Destination {
193 /// We're sending this onion message to a node.
195 /// We're sending this onion message to a blinded path.
196 BlindedPath(BlindedPath),
200 pub(super) fn num_hops(&self) -> usize {
202 Destination::Node(_) => 1,
203 Destination::BlindedPath(BlindedPath { blinded_hops, .. }) => blinded_hops.len(),
208 /// Errors that may occur when [sending an onion message].
210 /// [sending an onion message]: OnionMessenger::send_onion_message
211 #[derive(Debug, PartialEq, Eq)]
213 /// Errored computing onion message packet keys.
214 Secp256k1(secp256k1::Error),
215 /// Because implementations such as Eclair will drop onion messages where the message packet
216 /// exceeds 32834 bytes, we refuse to send messages where the packet exceeds this size.
218 /// The provided [`Destination`] was an invalid [`BlindedPath`], due to having fewer than two
221 /// Our next-hop peer was offline or does not support onion message forwarding.
223 /// Onion message contents must have a TLV type >= 64.
225 /// Our next-hop peer's buffer was full or our total outbound buffer was full.
227 /// Failed to retrieve our node id from the provided [`NodeSigner`].
229 /// [`NodeSigner`]: crate::sign::NodeSigner
231 /// We attempted to send to a blinded path where we are the introduction node, and failed to
232 /// advance the blinded path to make the second hop the new introduction node. Either
233 /// [`NodeSigner::ecdh`] failed, we failed to tweak the current blinding point to get the
234 /// new blinding point, or we were attempting to send to ourselves.
235 BlindedPathAdvanceFailed,
238 /// Handler for custom onion messages. If you are using [`SimpleArcOnionMessenger`],
239 /// [`SimpleRefOnionMessenger`], or prefer to ignore inbound custom onion messages,
240 /// [`IgnoringMessageHandler`] must be provided to [`OnionMessenger::new`]. Otherwise, a custom
241 /// implementation of this trait must be provided, with [`CustomMessage`] specifying the supported
244 /// See [`OnionMessenger`] for example usage.
246 /// [`IgnoringMessageHandler`]: crate::ln::peer_handler::IgnoringMessageHandler
247 /// [`CustomMessage`]: Self::CustomMessage
248 pub trait CustomOnionMessageHandler {
249 /// The message known to the handler. To support multiple message types, you may want to make this
250 /// an enum with a variant for each supported message.
251 type CustomMessage: CustomOnionMessageContents;
253 /// Called with the custom message that was received, returning a response to send, if any.
254 fn handle_custom_message(&self, msg: Self::CustomMessage) -> Option<Self::CustomMessage>;
256 /// Read a custom message of type `message_type` from `buffer`, returning `Ok(None)` if the
257 /// message type is unknown.
258 fn read_custom_message<R: io::Read>(&self, message_type: u64, buffer: &mut R) -> Result<Option<Self::CustomMessage>, msgs::DecodeError>;
261 /// A processed incoming onion message, containing either a Forward (another onion message)
262 /// or a Receive payload with decrypted contents.
263 pub enum PeeledOnion<CM: CustomOnionMessageContents> {
264 /// Forwarded onion, with the next node id and a new onion
265 Forward(PublicKey, msgs::OnionMessage),
266 /// Received onion message, with decrypted contents, path_id, and reply path
267 Receive(OnionMessageContents<CM>, Option<[u8; 32]>, Option<BlindedPath>)
270 /// Create an onion message with contents `message` to the destination of `path`.
271 /// Returns (first_node_id, onion_msg)
272 pub fn create_onion_message<ES: Deref, NS: Deref, T: CustomOnionMessageContents>(
273 entropy_source: &ES, node_signer: &NS, secp_ctx: &Secp256k1<secp256k1::All>,
274 path: OnionMessagePath, message: OnionMessageContents<T>, reply_path: Option<BlindedPath>,
275 ) -> Result<(PublicKey, msgs::OnionMessage), SendError>
277 ES::Target: EntropySource,
278 NS::Target: NodeSigner,
280 let OnionMessagePath { intermediate_nodes, mut destination } = path;
281 if let Destination::BlindedPath(BlindedPath { ref blinded_hops, .. }) = destination {
282 if blinded_hops.len() < 2 {
283 return Err(SendError::TooFewBlindedHops);
287 if message.tlv_type() < 64 { return Err(SendError::InvalidMessage) }
289 // If we are sending straight to a blinded path and we are the introduction node, we need to
290 // advance the blinded path by 1 hop so the second hop is the new introduction node.
291 if intermediate_nodes.len() == 0 {
292 if let Destination::BlindedPath(ref mut blinded_path) = destination {
293 let our_node_id = node_signer.get_node_id(Recipient::Node)
294 .map_err(|()| SendError::GetNodeIdFailed)?;
295 if blinded_path.introduction_node_id == our_node_id {
296 advance_path_by_one(blinded_path, node_signer, &secp_ctx)
297 .map_err(|()| SendError::BlindedPathAdvanceFailed)?;
302 let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
303 let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
304 let (first_node_id, blinding_point) = if let Some(first_node_id) = intermediate_nodes.first() {
305 (*first_node_id, PublicKey::from_secret_key(&secp_ctx, &blinding_secret))
308 Destination::Node(pk) => (pk, PublicKey::from_secret_key(&secp_ctx, &blinding_secret)),
309 Destination::BlindedPath(BlindedPath { introduction_node_id, blinding_point, .. }) =>
310 (introduction_node_id, blinding_point),
313 let (packet_payloads, packet_keys) = packet_payloads_and_keys(
314 &secp_ctx, &intermediate_nodes, destination, message, reply_path, &blinding_secret)
315 .map_err(|e| SendError::Secp256k1(e))?;
317 let prng_seed = entropy_source.get_secure_random_bytes();
318 let onion_routing_packet = construct_onion_message_packet(
319 packet_payloads, packet_keys, prng_seed).map_err(|()| SendError::TooBigPacket)?;
321 Ok((first_node_id, msgs::OnionMessage {
327 /// Decode one layer of an incoming onion message
328 /// Returns either a Forward (another onion message), or Receive (decrypted content)
329 pub fn peel_onion<NS: Deref, L: Deref, CMH: Deref>(
330 node_signer: NS, secp_ctx: &Secp256k1<secp256k1::All>, logger: L, custom_handler: CMH,
331 msg: &msgs::OnionMessage,
332 ) -> Result<PeeledOnion<<<CMH>::Target as CustomOnionMessageHandler>::CustomMessage>, ()>
334 NS::Target: NodeSigner,
336 CMH::Target: CustomOnionMessageHandler,
338 let control_tlvs_ss = match node_signer.ecdh(Recipient::Node, &msg.blinding_point, None) {
341 log_error!(logger, "Failed to retrieve node secret: {:?}", e);
345 let onion_decode_ss = {
346 let blinding_factor = {
347 let mut hmac = HmacEngine::<Sha256>::new(b"blinded_node_id");
348 hmac.input(control_tlvs_ss.as_ref());
349 Hmac::from_engine(hmac).into_inner()
351 match node_signer.ecdh(Recipient::Node, &msg.onion_routing_packet.public_key,
352 Some(&Scalar::from_be_bytes(blinding_factor).unwrap()))
354 Ok(ss) => ss.secret_bytes(),
356 log_trace!(logger, "Failed to compute onion packet shared secret");
361 match onion_utils::decode_next_untagged_hop(
362 onion_decode_ss, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
363 (control_tlvs_ss, custom_handler.deref(), logger.deref())
365 Ok((Payload::Receive::<<<CMH as Deref>::Target as CustomOnionMessageHandler>::CustomMessage> {
366 message, control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id }), reply_path,
368 Ok(PeeledOnion::Receive(message, path_id, reply_path))
370 Ok((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
371 next_node_id, next_blinding_override
372 })), Some((next_hop_hmac, new_packet_bytes)))) => {
373 // TODO: we need to check whether `next_node_id` is our node, in which case this is a dummy
374 // blinded hop and this onion message is destined for us. In this situation, we should keep
375 // unwrapping the onion layers to get to the final payload. Since we don't have the option
376 // of creating blinded paths with dummy hops currently, we should be ok to not handle this
378 let new_pubkey = match onion_utils::next_hop_pubkey(&secp_ctx, msg.onion_routing_packet.public_key, &onion_decode_ss) {
381 log_trace!(logger, "Failed to compute next hop packet pubkey: {}", e);
385 let outgoing_packet = Packet {
387 public_key: new_pubkey,
388 hop_data: new_packet_bytes,
391 let onion_message = msgs::OnionMessage {
392 blinding_point: match next_blinding_override {
393 Some(blinding_point) => blinding_point,
395 match onion_utils::next_hop_pubkey(
396 &secp_ctx, msg.blinding_point, control_tlvs_ss.as_ref()
400 log_trace!(logger, "Failed to compute next blinding point: {}", e);
406 onion_routing_packet: outgoing_packet,
409 Ok(PeeledOnion::Forward(next_node_id, onion_message))
412 log_trace!(logger, "Errored decoding onion message packet: {:?}", e);
416 log_trace!(logger, "Received bogus onion message packet, either the sender encoded a final hop as a forwarding hop or vice versa");
422 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref>
423 OnionMessenger<ES, NS, L, MR, OMH, CMH>
425 ES::Target: EntropySource,
426 NS::Target: NodeSigner,
428 MR::Target: MessageRouter,
429 OMH::Target: OffersMessageHandler,
430 CMH::Target: CustomOnionMessageHandler,
432 /// Constructs a new `OnionMessenger` to send, forward, and delegate received onion messages to
433 /// their respective handlers.
435 entropy_source: ES, node_signer: NS, logger: L, message_router: MR, offers_handler: OMH,
438 let mut secp_ctx = Secp256k1::new();
439 secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
443 pending_messages: Mutex::new(HashMap::new()),
452 /// Send an onion message with contents `message` to the destination of `path`.
454 /// See [`OnionMessenger`] for example usage.
455 pub fn send_onion_message<T: CustomOnionMessageContents>(
456 &self, path: OnionMessagePath, message: OnionMessageContents<T>,
457 reply_path: Option<BlindedPath>
458 ) -> Result<(), SendError> {
459 let (first_node_id, onion_msg) = create_onion_message(
460 &self.entropy_source, &self.node_signer, &self.secp_ctx,
461 path, message, reply_path
464 let mut pending_per_peer_msgs = self.pending_messages.lock().unwrap();
465 if outbound_buffer_full(&first_node_id, &pending_per_peer_msgs) { return Err(SendError::BufferFull) }
466 match pending_per_peer_msgs.entry(first_node_id) {
467 hash_map::Entry::Vacant(_) => Err(SendError::InvalidFirstHop),
468 hash_map::Entry::Occupied(mut e) => {
469 e.get_mut().push_back(onion_msg);
475 fn respond_with_onion_message<T: CustomOnionMessageContents>(
476 &self, response: OnionMessageContents<T>, path_id: Option<[u8; 32]>,
477 reply_path: Option<BlindedPath>
479 let sender = match self.node_signer.get_node_id(Recipient::Node) {
480 Ok(node_id) => node_id,
483 self.logger, "Unable to retrieve node id when responding to onion message with \
484 path_id {:02x?}", path_id
490 let peers = self.pending_messages.lock().unwrap().keys().copied().collect();
492 let destination = match reply_path {
493 Some(reply_path) => Destination::BlindedPath(reply_path),
496 self.logger, "Missing reply path when responding to onion message with path_id \
503 let path = match self.message_router.find_path(sender, peers, destination) {
507 self.logger, "Failed to find path when responding to onion message with \
508 path_id {:02x?}", path_id
514 log_trace!(self.logger, "Responding to onion message with path_id {:02x?}", path_id);
516 if let Err(e) = self.send_onion_message(path, response, None) {
518 self.logger, "Failed responding to onion message with path_id {:02x?}: {:?}",
526 pub(super) fn release_pending_msgs(&self) -> HashMap<PublicKey, VecDeque<msgs::OnionMessage>> {
527 let mut pending_msgs = self.pending_messages.lock().unwrap();
528 let mut msgs = HashMap::new();
529 // We don't want to disconnect the peers by removing them entirely from the original map, so we
530 // swap the pending message buffers individually.
531 for (peer_node_id, pending_messages) in &mut *pending_msgs {
532 msgs.insert(*peer_node_id, core::mem::take(pending_messages));
538 fn outbound_buffer_full(peer_node_id: &PublicKey, buffer: &HashMap<PublicKey, VecDeque<msgs::OnionMessage>>) -> bool {
539 const MAX_TOTAL_BUFFER_SIZE: usize = (1 << 20) * 128;
540 const MAX_PER_PEER_BUFFER_SIZE: usize = (1 << 10) * 256;
541 let mut total_buffered_bytes = 0;
542 let mut peer_buffered_bytes = 0;
543 for (pk, peer_buf) in buffer {
545 let om_len = om.serialized_length();
546 if pk == peer_node_id {
547 peer_buffered_bytes += om_len;
549 total_buffered_bytes += om_len;
551 if total_buffered_bytes >= MAX_TOTAL_BUFFER_SIZE ||
552 peer_buffered_bytes >= MAX_PER_PEER_BUFFER_SIZE
561 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref> OnionMessageHandler
562 for OnionMessenger<ES, NS, L, MR, OMH, CMH>
564 ES::Target: EntropySource,
565 NS::Target: NodeSigner,
567 MR::Target: MessageRouter,
568 OMH::Target: OffersMessageHandler,
569 CMH::Target: CustomOnionMessageHandler,
571 /// Handle an incoming onion message. Currently, if a message was destined for us we will log, but
572 /// soon we'll delegate the onion message to a handler that can generate invoices or send
574 fn handle_onion_message(&self, _peer_node_id: &PublicKey, msg: &msgs::OnionMessage) {
576 &*self.node_signer, &self.secp_ctx, &*self.logger, &*self.custom_handler, msg
578 Ok(PeeledOnion::Receive(message, path_id, reply_path)) => {
579 log_trace!(self.logger,
580 "Received an onion message with path_id {:02x?} and {} reply_path",
581 path_id, if reply_path.is_some() { "a" } else { "no" });
582 let response = match message {
583 OnionMessageContents::Offers(msg) => {
584 self.offers_handler.handle_message(msg)
585 .map(|msg| OnionMessageContents::Offers(msg))
587 OnionMessageContents::Custom(msg) => {
588 self.custom_handler.handle_custom_message(msg)
589 .map(|msg| OnionMessageContents::Custom(msg))
592 if let Some(response) = response {
593 self.respond_with_onion_message(response, path_id, reply_path);
596 Ok(PeeledOnion::Forward(next_node_id, onion_message)) => {
597 let mut pending_per_peer_msgs = self.pending_messages.lock().unwrap();
598 if outbound_buffer_full(&next_node_id, &pending_per_peer_msgs) {
599 log_trace!(self.logger, "Dropping forwarded onion message to peer {:?}: outbound buffer full", next_node_id);
604 pending_per_peer_msgs.entry(next_node_id).or_insert_with(VecDeque::new);
606 match pending_per_peer_msgs.entry(next_node_id) {
607 hash_map::Entry::Vacant(_) => {
608 log_trace!(self.logger, "Dropping forwarded onion message to disconnected peer {:?}", next_node_id);
611 hash_map::Entry::Occupied(mut e) => {
612 e.get_mut().push_back(onion_message);
613 log_trace!(self.logger, "Forwarding an onion message to peer {}", next_node_id);
618 log_error!(self.logger, "Failed to process onion message {:?}", e);
623 fn peer_connected(&self, their_node_id: &PublicKey, init: &msgs::Init, _inbound: bool) -> Result<(), ()> {
624 if init.features.supports_onion_messages() {
625 let mut peers = self.pending_messages.lock().unwrap();
626 peers.insert(their_node_id.clone(), VecDeque::new());
631 fn peer_disconnected(&self, their_node_id: &PublicKey) {
632 let mut pending_msgs = self.pending_messages.lock().unwrap();
633 pending_msgs.remove(their_node_id);
636 fn provided_node_features(&self) -> NodeFeatures {
637 let mut features = NodeFeatures::empty();
638 features.set_onion_messages_optional();
642 fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
643 let mut features = InitFeatures::empty();
644 features.set_onion_messages_optional();
648 fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<msgs::OnionMessage> {
649 let mut pending_msgs = self.pending_messages.lock().unwrap();
650 if let Some(msgs) = pending_msgs.get_mut(&peer_node_id) {
651 return msgs.pop_front()
657 // TODO: parameterize the below Simple* types with OnionMessenger and handle the messages it
659 /// Useful for simplifying the parameters of [`SimpleArcChannelManager`] and
660 /// [`SimpleArcPeerManager`]. See their docs for more details.
662 /// This is not exported to bindings users as `Arc`s don't make sense in bindings.
664 /// [`SimpleArcChannelManager`]: crate::ln::channelmanager::SimpleArcChannelManager
665 /// [`SimpleArcPeerManager`]: crate::ln::peer_handler::SimpleArcPeerManager
666 pub type SimpleArcOnionMessenger<L> = OnionMessenger<
670 Arc<DefaultMessageRouter>,
671 IgnoringMessageHandler,
672 IgnoringMessageHandler
675 /// Useful for simplifying the parameters of [`SimpleRefChannelManager`] and
676 /// [`SimpleRefPeerManager`]. See their docs for more details.
678 /// This is not exported to bindings users as general type aliases don't make sense in bindings.
680 /// [`SimpleRefChannelManager`]: crate::ln::channelmanager::SimpleRefChannelManager
681 /// [`SimpleRefPeerManager`]: crate::ln::peer_handler::SimpleRefPeerManager
682 pub type SimpleRefOnionMessenger<'a, 'b, 'c, L> = OnionMessenger<
686 &'c DefaultMessageRouter,
687 IgnoringMessageHandler,
688 IgnoringMessageHandler
691 /// Construct onion packet payloads and keys for sending an onion message along the given
692 /// `unblinded_path` to the given `destination`.
693 fn packet_payloads_and_keys<T: CustomOnionMessageContents, S: secp256k1::Signing + secp256k1::Verification>(
694 secp_ctx: &Secp256k1<S>, unblinded_path: &[PublicKey], destination: Destination,
695 message: OnionMessageContents<T>, mut reply_path: Option<BlindedPath>, session_priv: &SecretKey
696 ) -> Result<(Vec<(Payload<T>, [u8; 32])>, Vec<onion_utils::OnionKeys>), secp256k1::Error> {
697 let num_hops = unblinded_path.len() + destination.num_hops();
698 let mut payloads = Vec::with_capacity(num_hops);
699 let mut onion_packet_keys = Vec::with_capacity(num_hops);
701 let (mut intro_node_id_blinding_pt, num_blinded_hops) = if let Destination::BlindedPath(BlindedPath {
702 introduction_node_id, blinding_point, blinded_hops }) = &destination {
703 (Some((*introduction_node_id, *blinding_point)), blinded_hops.len()) } else { (None, 0) };
704 let num_unblinded_hops = num_hops - num_blinded_hops;
706 let mut unblinded_path_idx = 0;
707 let mut blinded_path_idx = 0;
708 let mut prev_control_tlvs_ss = None;
709 let mut final_control_tlvs = None;
710 utils::construct_keys_callback(secp_ctx, unblinded_path.iter(), Some(destination), session_priv,
711 |_, onion_packet_ss, ephemeral_pubkey, control_tlvs_ss, unblinded_pk_opt, enc_payload_opt| {
712 if num_unblinded_hops != 0 && unblinded_path_idx < num_unblinded_hops {
713 if let Some(ss) = prev_control_tlvs_ss.take() {
714 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(
716 next_node_id: unblinded_pk_opt.unwrap(),
717 next_blinding_override: None,
721 prev_control_tlvs_ss = Some(control_tlvs_ss);
722 unblinded_path_idx += 1;
723 } else if let Some((intro_node_id, blinding_pt)) = intro_node_id_blinding_pt.take() {
724 if let Some(control_tlvs_ss) = prev_control_tlvs_ss.take() {
725 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
726 next_node_id: intro_node_id,
727 next_blinding_override: Some(blinding_pt),
728 })), control_tlvs_ss));
731 if blinded_path_idx < num_blinded_hops.saturating_sub(1) && enc_payload_opt.is_some() {
732 payloads.push((Payload::Forward(ForwardControlTlvs::Blinded(enc_payload_opt.unwrap())),
734 blinded_path_idx += 1;
735 } else if let Some(encrypted_payload) = enc_payload_opt {
736 final_control_tlvs = Some(ReceiveControlTlvs::Blinded(encrypted_payload));
737 prev_control_tlvs_ss = Some(control_tlvs_ss);
740 let (rho, mu) = onion_utils::gen_rho_mu_from_shared_secret(onion_packet_ss.as_ref());
741 onion_packet_keys.push(onion_utils::OnionKeys {
743 shared_secret: onion_packet_ss,
745 blinding_factor: [0; 32],
753 if let Some(control_tlvs) = final_control_tlvs {
754 payloads.push((Payload::Receive {
756 reply_path: reply_path.take(),
758 }, prev_control_tlvs_ss.unwrap()));
760 payloads.push((Payload::Receive {
761 control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id: None, }),
762 reply_path: reply_path.take(),
764 }, prev_control_tlvs_ss.unwrap()));
767 Ok((payloads, onion_packet_keys))
770 /// Errors if the serialized payload size exceeds onion_message::BIG_PACKET_HOP_DATA_LEN
771 fn construct_onion_message_packet<T: CustomOnionMessageContents>(payloads: Vec<(Payload<T>, [u8; 32])>, onion_keys: Vec<onion_utils::OnionKeys>, prng_seed: [u8; 32]) -> Result<Packet, ()> {
773 // "`len` allows larger messages to be sent than the standard 1300 bytes allowed for an HTLC
774 // onion, but this should be used sparingly as it is reduces anonymity set, hence the
775 // recommendation that it either look like an HTLC onion, or if larger, be a fixed size."
776 let payloads_ser_len = onion_utils::payloads_serialized_length(&payloads);
777 let hop_data_len = if payloads_ser_len <= SMALL_PACKET_HOP_DATA_LEN {
778 SMALL_PACKET_HOP_DATA_LEN
779 } else if payloads_ser_len <= BIG_PACKET_HOP_DATA_LEN {
780 BIG_PACKET_HOP_DATA_LEN
781 } else { return Err(()) };
783 onion_utils::construct_onion_message_packet::<_, _>(
784 payloads, onion_keys, prng_seed, hop_data_len)