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, OnionMessage, OnionMessageHandler};
24 use crate::ln::onion_utils;
25 use crate::ln::peer_handler::IgnoringMessageHandler;
26 pub use super::packet::OnionMessageContents;
27 use super::packet::ParsedOnionMessageContents;
28 use super::offers::OffersMessageHandler;
29 use super::packet::{BIG_PACKET_HOP_DATA_LEN, ForwardControlTlvs, Packet, Payload, ReceiveControlTlvs, SMALL_PACKET_HOP_DATA_LEN};
30 use crate::util::logger::Logger;
31 use crate::util::ser::Writeable;
36 use crate::sync::{Arc, Mutex};
37 use crate::prelude::*;
39 /// A sender, receiver and forwarder of [`OnionMessage`]s.
41 /// # Handling Messages
43 /// `OnionMessenger` implements [`OnionMessageHandler`], making it responsible for either forwarding
44 /// messages to peers or delegating to the appropriate handler for the message type. Currently, the
45 /// available handlers are:
46 /// * [`OffersMessageHandler`], for responding to [`InvoiceRequest`]s and paying [`Bolt12Invoice`]s
47 /// * [`CustomOnionMessageHandler`], for handling user-defined message types
49 /// # Sending Messages
51 /// [`OnionMessage`]s are sent initially using [`OnionMessenger::send_onion_message`]. When handling
52 /// a message, the matched handler may return a response message which `OnionMessenger` will send
58 /// # extern crate bitcoin;
59 /// # use bitcoin::hashes::_export::_core::time::Duration;
60 /// # use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey};
61 /// # use lightning::blinded_path::BlindedPath;
62 /// # use lightning::sign::KeysManager;
63 /// # use lightning::ln::peer_handler::IgnoringMessageHandler;
64 /// # use lightning::onion_message::{OnionMessageContents, Destination, MessageRouter, OnionMessagePath, OnionMessenger};
65 /// # use lightning::util::logger::{Logger, Record};
66 /// # use lightning::util::ser::{Writeable, Writer};
67 /// # use lightning::io;
68 /// # use std::sync::Arc;
69 /// # struct FakeLogger;
70 /// # impl Logger for FakeLogger {
71 /// # fn log(&self, record: &Record) { unimplemented!() }
73 /// # struct FakeMessageRouter {}
74 /// # impl MessageRouter for FakeMessageRouter {
75 /// # fn find_path(&self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination) -> Result<OnionMessagePath, ()> {
76 /// # unimplemented!()
79 /// # let seed = [42u8; 32];
80 /// # let time = Duration::from_secs(123456);
81 /// # let keys_manager = KeysManager::new(&seed, time.as_secs(), time.subsec_nanos());
82 /// # let logger = Arc::new(FakeLogger {});
83 /// # let node_secret = SecretKey::from_slice(&hex::decode("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
84 /// # let secp_ctx = Secp256k1::new();
85 /// # let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
86 /// # let (hop_node_id2, hop_node_id3, hop_node_id4) = (hop_node_id1, hop_node_id1, hop_node_id1);
87 /// # let destination_node_id = hop_node_id1;
88 /// # let message_router = Arc::new(FakeMessageRouter {});
89 /// # let custom_message_handler = IgnoringMessageHandler {};
90 /// # let offers_message_handler = IgnoringMessageHandler {};
91 /// // Create the onion messenger. This must use the same `keys_manager` as is passed to your
92 /// // ChannelManager.
93 /// let onion_messenger = OnionMessenger::new(
94 /// &keys_manager, &keys_manager, logger, message_router, &offers_message_handler,
95 /// &custom_message_handler
98 /// # struct YourCustomMessage {}
99 /// impl Writeable for YourCustomMessage {
100 /// fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
102 /// // Write your custom onion message to `w`
105 /// impl OnionMessageContents for YourCustomMessage {
106 /// fn tlv_type(&self) -> u64 {
107 /// # let your_custom_message_type = 42;
108 /// your_custom_message_type
111 /// // Send a custom onion message to a node id.
112 /// let path = OnionMessagePath {
113 /// intermediate_nodes: vec![hop_node_id1, hop_node_id2],
114 /// destination: Destination::Node(destination_node_id),
116 /// let reply_path = None;
117 /// # let message = YourCustomMessage {};
118 /// onion_messenger.send_onion_message(path, message, reply_path);
120 /// // Create a blinded path to yourself, for someone to send an onion message to.
121 /// # let your_node_id = hop_node_id1;
122 /// let hops = [hop_node_id3, hop_node_id4, your_node_id];
123 /// let blinded_path = BlindedPath::new_for_message(&hops, &keys_manager, &secp_ctx).unwrap();
125 /// // Send a custom onion message to a blinded path.
126 /// let path = OnionMessagePath {
127 /// intermediate_nodes: vec![hop_node_id1, hop_node_id2],
128 /// destination: Destination::BlindedPath(blinded_path),
130 /// let reply_path = None;
131 /// # let message = YourCustomMessage {};
132 /// onion_messenger.send_onion_message(path, message, reply_path);
135 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
136 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
137 pub struct OnionMessenger<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref>
139 ES::Target: EntropySource,
140 NS::Target: NodeSigner,
142 MR::Target: MessageRouter,
143 OMH::Target: OffersMessageHandler,
144 CMH:: Target: CustomOnionMessageHandler,
149 pending_messages: Mutex<HashMap<PublicKey, VecDeque<OnionMessage>>>,
150 secp_ctx: Secp256k1<secp256k1::All>,
156 /// A trait defining behavior for routing an [`OnionMessage`].
157 pub trait MessageRouter {
158 /// Returns a route for sending an [`OnionMessage`] to the given [`Destination`].
160 &self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
161 ) -> Result<OnionMessagePath, ()>;
164 /// A [`MessageRouter`] that always fails.
165 pub struct DefaultMessageRouter;
167 impl MessageRouter for DefaultMessageRouter {
169 &self, _sender: PublicKey, _peers: Vec<PublicKey>, _destination: Destination
170 ) -> Result<OnionMessagePath, ()> {
175 /// A path for sending an [`OnionMessage`].
177 pub struct OnionMessagePath {
178 /// Nodes on the path between the sender and the destination.
179 pub intermediate_nodes: Vec<PublicKey>,
181 /// The recipient of the message.
182 pub destination: Destination,
185 /// The destination of an onion message.
187 pub enum Destination {
188 /// We're sending this onion message to a node.
190 /// We're sending this onion message to a blinded path.
191 BlindedPath(BlindedPath),
195 pub(super) fn num_hops(&self) -> usize {
197 Destination::Node(_) => 1,
198 Destination::BlindedPath(BlindedPath { blinded_hops, .. }) => blinded_hops.len(),
203 /// Errors that may occur when [sending an onion message].
205 /// [sending an onion message]: OnionMessenger::send_onion_message
206 #[derive(Debug, PartialEq, Eq)]
208 /// Errored computing onion message packet keys.
209 Secp256k1(secp256k1::Error),
210 /// Because implementations such as Eclair will drop onion messages where the message packet
211 /// exceeds 32834 bytes, we refuse to send messages where the packet exceeds this size.
213 /// The provided [`Destination`] was an invalid [`BlindedPath`], due to having fewer than two
216 /// Our next-hop peer was offline or does not support onion message forwarding.
218 /// Onion message contents must have a TLV type >= 64.
220 /// Our next-hop peer's buffer was full or our total outbound buffer was full.
222 /// Failed to retrieve our node id from the provided [`NodeSigner`].
224 /// [`NodeSigner`]: crate::sign::NodeSigner
226 /// We attempted to send to a blinded path where we are the introduction node, and failed to
227 /// advance the blinded path to make the second hop the new introduction node. Either
228 /// [`NodeSigner::ecdh`] failed, we failed to tweak the current blinding point to get the
229 /// new blinding point, or we were attempting to send to ourselves.
230 BlindedPathAdvanceFailed,
233 /// Handler for custom onion messages. If you are using [`SimpleArcOnionMessenger`],
234 /// [`SimpleRefOnionMessenger`], or prefer to ignore inbound custom onion messages,
235 /// [`IgnoringMessageHandler`] must be provided to [`OnionMessenger::new`]. Otherwise, a custom
236 /// implementation of this trait must be provided, with [`CustomMessage`] specifying the supported
239 /// See [`OnionMessenger`] for example usage.
241 /// [`IgnoringMessageHandler`]: crate::ln::peer_handler::IgnoringMessageHandler
242 /// [`CustomMessage`]: Self::CustomMessage
243 pub trait CustomOnionMessageHandler {
244 /// The message known to the handler. To support multiple message types, you may want to make this
245 /// an enum with a variant for each supported message.
246 type CustomMessage: OnionMessageContents;
248 /// Called with the custom message that was received, returning a response to send, if any.
249 fn handle_custom_message(&self, msg: Self::CustomMessage) -> Option<Self::CustomMessage>;
251 /// Read a custom message of type `message_type` from `buffer`, returning `Ok(None)` if the
252 /// message type is unknown.
253 fn read_custom_message<R: io::Read>(&self, message_type: u64, buffer: &mut R) -> Result<Option<Self::CustomMessage>, msgs::DecodeError>;
256 /// A processed incoming onion message, containing either a Forward (another onion message)
257 /// or a Receive payload with decrypted contents.
258 pub enum PeeledOnion<T: OnionMessageContents> {
259 /// Forwarded onion, with the next node id and a new onion
260 Forward(PublicKey, OnionMessage),
261 /// Received onion message, with decrypted contents, path_id, and reply path
262 Receive(ParsedOnionMessageContents<T>, Option<[u8; 32]>, Option<BlindedPath>)
265 /// Creates an [`OnionMessage`] with the given `contents` for sending to the destination of
268 /// Returns both the node id of the peer to send the message to and the message itself.
269 pub fn create_onion_message<ES: Deref, NS: Deref, T: OnionMessageContents>(
270 entropy_source: &ES, node_signer: &NS, secp_ctx: &Secp256k1<secp256k1::All>,
271 path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
272 ) -> Result<(PublicKey, OnionMessage), SendError>
274 ES::Target: EntropySource,
275 NS::Target: NodeSigner,
277 let OnionMessagePath { intermediate_nodes, mut destination } = path;
278 if let Destination::BlindedPath(BlindedPath { ref blinded_hops, .. }) = destination {
279 if blinded_hops.len() < 2 {
280 return Err(SendError::TooFewBlindedHops);
284 if contents.tlv_type() < 64 { return Err(SendError::InvalidMessage) }
286 // If we are sending straight to a blinded path and we are the introduction node, we need to
287 // advance the blinded path by 1 hop so the second hop is the new introduction node.
288 if intermediate_nodes.len() == 0 {
289 if let Destination::BlindedPath(ref mut blinded_path) = destination {
290 let our_node_id = node_signer.get_node_id(Recipient::Node)
291 .map_err(|()| SendError::GetNodeIdFailed)?;
292 if blinded_path.introduction_node_id == our_node_id {
293 advance_path_by_one(blinded_path, node_signer, &secp_ctx)
294 .map_err(|()| SendError::BlindedPathAdvanceFailed)?;
299 let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
300 let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
301 let (first_node_id, blinding_point) = if let Some(first_node_id) = intermediate_nodes.first() {
302 (*first_node_id, PublicKey::from_secret_key(&secp_ctx, &blinding_secret))
305 Destination::Node(pk) => (pk, PublicKey::from_secret_key(&secp_ctx, &blinding_secret)),
306 Destination::BlindedPath(BlindedPath { introduction_node_id, blinding_point, .. }) =>
307 (introduction_node_id, blinding_point),
310 let (packet_payloads, packet_keys) = packet_payloads_and_keys(
311 &secp_ctx, &intermediate_nodes, destination, contents, reply_path, &blinding_secret)
312 .map_err(|e| SendError::Secp256k1(e))?;
314 let prng_seed = entropy_source.get_secure_random_bytes();
315 let onion_routing_packet = construct_onion_message_packet(
316 packet_payloads, packet_keys, prng_seed).map_err(|()| SendError::TooBigPacket)?;
318 Ok((first_node_id, OnionMessage {
324 /// Decode one layer of an incoming onion message
325 /// Returns either a Forward (another onion message), or Receive (decrypted content)
326 pub fn peel_onion<NS: Deref, L: Deref, CMH: Deref>(
327 node_signer: NS, secp_ctx: &Secp256k1<secp256k1::All>, logger: L, custom_handler: CMH,
329 ) -> Result<PeeledOnion<<<CMH>::Target as CustomOnionMessageHandler>::CustomMessage>, ()>
331 NS::Target: NodeSigner,
333 CMH::Target: CustomOnionMessageHandler,
335 let control_tlvs_ss = match node_signer.ecdh(Recipient::Node, &msg.blinding_point, None) {
338 log_error!(logger, "Failed to retrieve node secret: {:?}", e);
342 let onion_decode_ss = {
343 let blinding_factor = {
344 let mut hmac = HmacEngine::<Sha256>::new(b"blinded_node_id");
345 hmac.input(control_tlvs_ss.as_ref());
346 Hmac::from_engine(hmac).into_inner()
348 match node_signer.ecdh(Recipient::Node, &msg.onion_routing_packet.public_key,
349 Some(&Scalar::from_be_bytes(blinding_factor).unwrap()))
351 Ok(ss) => ss.secret_bytes(),
353 log_trace!(logger, "Failed to compute onion packet shared secret");
358 match onion_utils::decode_next_untagged_hop(
359 onion_decode_ss, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
360 (control_tlvs_ss, custom_handler.deref(), logger.deref())
362 Ok((Payload::Receive::<ParsedOnionMessageContents<<<CMH as Deref>::Target as CustomOnionMessageHandler>::CustomMessage>> {
363 message, control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id }), reply_path,
365 Ok(PeeledOnion::Receive(message, path_id, reply_path))
367 Ok((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
368 next_node_id, next_blinding_override
369 })), Some((next_hop_hmac, new_packet_bytes)))) => {
370 // TODO: we need to check whether `next_node_id` is our node, in which case this is a dummy
371 // blinded hop and this onion message is destined for us. In this situation, we should keep
372 // unwrapping the onion layers to get to the final payload. Since we don't have the option
373 // of creating blinded paths with dummy hops currently, we should be ok to not handle this
375 let new_pubkey = match onion_utils::next_hop_pubkey(&secp_ctx, msg.onion_routing_packet.public_key, &onion_decode_ss) {
378 log_trace!(logger, "Failed to compute next hop packet pubkey: {}", e);
382 let outgoing_packet = Packet {
384 public_key: new_pubkey,
385 hop_data: new_packet_bytes,
388 let onion_message = OnionMessage {
389 blinding_point: match next_blinding_override {
390 Some(blinding_point) => blinding_point,
392 match onion_utils::next_hop_pubkey(
393 &secp_ctx, msg.blinding_point, control_tlvs_ss.as_ref()
397 log_trace!(logger, "Failed to compute next blinding point: {}", e);
403 onion_routing_packet: outgoing_packet,
406 Ok(PeeledOnion::Forward(next_node_id, onion_message))
409 log_trace!(logger, "Errored decoding onion message packet: {:?}", e);
413 log_trace!(logger, "Received bogus onion message packet, either the sender encoded a final hop as a forwarding hop or vice versa");
419 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref>
420 OnionMessenger<ES, NS, L, MR, OMH, CMH>
422 ES::Target: EntropySource,
423 NS::Target: NodeSigner,
425 MR::Target: MessageRouter,
426 OMH::Target: OffersMessageHandler,
427 CMH::Target: CustomOnionMessageHandler,
429 /// Constructs a new `OnionMessenger` to send, forward, and delegate received onion messages to
430 /// their respective handlers.
432 entropy_source: ES, node_signer: NS, logger: L, message_router: MR, offers_handler: OMH,
435 let mut secp_ctx = Secp256k1::new();
436 secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
440 pending_messages: Mutex::new(HashMap::new()),
449 /// Sends an [`OnionMessage`] with the given `contents` for sending to the destination of
452 /// See [`OnionMessenger`] for example usage.
453 pub fn send_onion_message<T: OnionMessageContents>(
454 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>
455 ) -> Result<(), SendError> {
456 let (first_node_id, onion_msg) = create_onion_message(
457 &self.entropy_source, &self.node_signer, &self.secp_ctx, path, contents, reply_path
460 let mut pending_per_peer_msgs = self.pending_messages.lock().unwrap();
461 if outbound_buffer_full(&first_node_id, &pending_per_peer_msgs) { return Err(SendError::BufferFull) }
462 match pending_per_peer_msgs.entry(first_node_id) {
463 hash_map::Entry::Vacant(_) => Err(SendError::InvalidFirstHop),
464 hash_map::Entry::Occupied(mut e) => {
465 e.get_mut().push_back(onion_msg);
471 fn handle_onion_message_response<T: OnionMessageContents>(
472 &self, response: Option<T>, reply_path: Option<BlindedPath>, log_suffix: fmt::Arguments
474 if let Some(response) = response {
476 Some(reply_path) => {
477 self.find_path_and_enqueue_onion_message(
478 response, Destination::BlindedPath(reply_path), log_suffix
482 log_trace!(self.logger, "Missing reply path {}", log_suffix);
488 fn find_path_and_enqueue_onion_message<T: OnionMessageContents>(
489 &self, contents: T, destination: Destination, log_suffix: fmt::Arguments
491 let sender = match self.node_signer.get_node_id(Recipient::Node) {
492 Ok(node_id) => node_id,
494 log_warn!(self.logger, "Unable to retrieve node id {}", log_suffix);
499 let peers = self.pending_messages.lock().unwrap().keys().copied().collect();
500 let path = match self.message_router.find_path(sender, peers, destination) {
503 log_trace!(self.logger, "Failed to find path {}", log_suffix);
508 log_trace!(self.logger, "Sending onion message {}", log_suffix);
510 if let Err(e) = self.send_onion_message(path, contents, None) {
511 log_trace!(self.logger, "Failed sending onion message {}: {:?}", log_suffix, e);
517 pub(super) fn release_pending_msgs(&self) -> HashMap<PublicKey, VecDeque<OnionMessage>> {
518 let mut pending_msgs = self.pending_messages.lock().unwrap();
519 let mut msgs = HashMap::new();
520 // We don't want to disconnect the peers by removing them entirely from the original map, so we
521 // swap the pending message buffers individually.
522 for (peer_node_id, pending_messages) in &mut *pending_msgs {
523 msgs.insert(*peer_node_id, core::mem::take(pending_messages));
529 fn outbound_buffer_full(peer_node_id: &PublicKey, buffer: &HashMap<PublicKey, VecDeque<OnionMessage>>) -> bool {
530 const MAX_TOTAL_BUFFER_SIZE: usize = (1 << 20) * 128;
531 const MAX_PER_PEER_BUFFER_SIZE: usize = (1 << 10) * 256;
532 let mut total_buffered_bytes = 0;
533 let mut peer_buffered_bytes = 0;
534 for (pk, peer_buf) in buffer {
536 let om_len = om.serialized_length();
537 if pk == peer_node_id {
538 peer_buffered_bytes += om_len;
540 total_buffered_bytes += om_len;
542 if total_buffered_bytes >= MAX_TOTAL_BUFFER_SIZE ||
543 peer_buffered_bytes >= MAX_PER_PEER_BUFFER_SIZE
552 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref> OnionMessageHandler
553 for OnionMessenger<ES, NS, L, MR, OMH, CMH>
555 ES::Target: EntropySource,
556 NS::Target: NodeSigner,
558 MR::Target: MessageRouter,
559 OMH::Target: OffersMessageHandler,
560 CMH::Target: CustomOnionMessageHandler,
562 /// Handle an incoming onion message. Currently, if a message was destined for us we will log, but
563 /// soon we'll delegate the onion message to a handler that can generate invoices or send
565 fn handle_onion_message(&self, _peer_node_id: &PublicKey, msg: &OnionMessage) {
567 &*self.node_signer, &self.secp_ctx, &*self.logger, &*self.custom_handler, msg
569 Ok(PeeledOnion::Receive(message, path_id, reply_path)) => {
570 log_trace!(self.logger,
571 "Received an onion message with path_id {:02x?} and {} reply_path",
572 path_id, if reply_path.is_some() { "a" } else { "no" });
575 ParsedOnionMessageContents::Offers(msg) => {
576 let response = self.offers_handler.handle_message(msg);
577 self.handle_onion_message_response(
578 response, reply_path, format_args!(
579 "when responding to Offers onion message with path_id {:02x?}",
584 ParsedOnionMessageContents::Custom(msg) => {
585 let response = self.custom_handler.handle_custom_message(msg);
586 self.handle_onion_message_response(
587 response, reply_path, format_args!(
588 "when responding to Custom onion message with path_id {:02x?}",
595 Ok(PeeledOnion::Forward(next_node_id, onion_message)) => {
596 let mut pending_per_peer_msgs = self.pending_messages.lock().unwrap();
597 if outbound_buffer_full(&next_node_id, &pending_per_peer_msgs) {
598 log_trace!(self.logger, "Dropping forwarded onion message to peer {:?}: outbound buffer full", next_node_id);
603 pending_per_peer_msgs.entry(next_node_id).or_insert_with(VecDeque::new);
605 match pending_per_peer_msgs.entry(next_node_id) {
606 hash_map::Entry::Vacant(_) => {
607 log_trace!(self.logger, "Dropping forwarded onion message to disconnected peer {:?}", next_node_id);
610 hash_map::Entry::Occupied(mut e) => {
611 e.get_mut().push_back(onion_message);
612 log_trace!(self.logger, "Forwarding an onion message to peer {}", next_node_id);
617 log_error!(self.logger, "Failed to process onion message {:?}", e);
622 fn peer_connected(&self, their_node_id: &PublicKey, init: &msgs::Init, _inbound: bool) -> Result<(), ()> {
623 if init.features.supports_onion_messages() {
624 let mut peers = self.pending_messages.lock().unwrap();
625 peers.insert(their_node_id.clone(), VecDeque::new());
630 fn peer_disconnected(&self, their_node_id: &PublicKey) {
631 let mut pending_msgs = self.pending_messages.lock().unwrap();
632 pending_msgs.remove(their_node_id);
635 fn provided_node_features(&self) -> NodeFeatures {
636 let mut features = NodeFeatures::empty();
637 features.set_onion_messages_optional();
641 fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
642 let mut features = InitFeatures::empty();
643 features.set_onion_messages_optional();
647 fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<OnionMessage> {
648 let mut pending_msgs = self.pending_messages.lock().unwrap();
649 if let Some(msgs) = pending_msgs.get_mut(&peer_node_id) {
650 return msgs.pop_front()
656 // TODO: parameterize the below Simple* types with OnionMessenger and handle the messages it
658 /// Useful for simplifying the parameters of [`SimpleArcChannelManager`] and
659 /// [`SimpleArcPeerManager`]. See their docs for more details.
661 /// This is not exported to bindings users as `Arc`s don't make sense in bindings.
663 /// [`SimpleArcChannelManager`]: crate::ln::channelmanager::SimpleArcChannelManager
664 /// [`SimpleArcPeerManager`]: crate::ln::peer_handler::SimpleArcPeerManager
665 pub type SimpleArcOnionMessenger<L> = OnionMessenger<
669 Arc<DefaultMessageRouter>,
670 IgnoringMessageHandler,
671 IgnoringMessageHandler
674 /// Useful for simplifying the parameters of [`SimpleRefChannelManager`] and
675 /// [`SimpleRefPeerManager`]. See their docs for more details.
677 /// This is not exported to bindings users as general type aliases don't make sense in bindings.
679 /// [`SimpleRefChannelManager`]: crate::ln::channelmanager::SimpleRefChannelManager
680 /// [`SimpleRefPeerManager`]: crate::ln::peer_handler::SimpleRefPeerManager
681 pub type SimpleRefOnionMessenger<'a, 'b, 'c, L> = OnionMessenger<
685 &'c DefaultMessageRouter,
686 IgnoringMessageHandler,
687 IgnoringMessageHandler
690 /// Construct onion packet payloads and keys for sending an onion message along the given
691 /// `unblinded_path` to the given `destination`.
692 fn packet_payloads_and_keys<T: OnionMessageContents, S: secp256k1::Signing + secp256k1::Verification>(
693 secp_ctx: &Secp256k1<S>, unblinded_path: &[PublicKey], destination: Destination, message: T,
694 mut reply_path: Option<BlindedPath>, session_priv: &SecretKey
695 ) -> Result<(Vec<(Payload<T>, [u8; 32])>, Vec<onion_utils::OnionKeys>), secp256k1::Error> {
696 let num_hops = unblinded_path.len() + destination.num_hops();
697 let mut payloads = Vec::with_capacity(num_hops);
698 let mut onion_packet_keys = Vec::with_capacity(num_hops);
700 let (mut intro_node_id_blinding_pt, num_blinded_hops) = if let Destination::BlindedPath(BlindedPath {
701 introduction_node_id, blinding_point, blinded_hops }) = &destination {
702 (Some((*introduction_node_id, *blinding_point)), blinded_hops.len()) } else { (None, 0) };
703 let num_unblinded_hops = num_hops - num_blinded_hops;
705 let mut unblinded_path_idx = 0;
706 let mut blinded_path_idx = 0;
707 let mut prev_control_tlvs_ss = None;
708 let mut final_control_tlvs = None;
709 utils::construct_keys_callback(secp_ctx, unblinded_path.iter(), Some(destination), session_priv,
710 |_, onion_packet_ss, ephemeral_pubkey, control_tlvs_ss, unblinded_pk_opt, enc_payload_opt| {
711 if num_unblinded_hops != 0 && unblinded_path_idx < num_unblinded_hops {
712 if let Some(ss) = prev_control_tlvs_ss.take() {
713 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(
715 next_node_id: unblinded_pk_opt.unwrap(),
716 next_blinding_override: None,
720 prev_control_tlvs_ss = Some(control_tlvs_ss);
721 unblinded_path_idx += 1;
722 } else if let Some((intro_node_id, blinding_pt)) = intro_node_id_blinding_pt.take() {
723 if let Some(control_tlvs_ss) = prev_control_tlvs_ss.take() {
724 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
725 next_node_id: intro_node_id,
726 next_blinding_override: Some(blinding_pt),
727 })), control_tlvs_ss));
730 if blinded_path_idx < num_blinded_hops.saturating_sub(1) && enc_payload_opt.is_some() {
731 payloads.push((Payload::Forward(ForwardControlTlvs::Blinded(enc_payload_opt.unwrap())),
733 blinded_path_idx += 1;
734 } else if let Some(encrypted_payload) = enc_payload_opt {
735 final_control_tlvs = Some(ReceiveControlTlvs::Blinded(encrypted_payload));
736 prev_control_tlvs_ss = Some(control_tlvs_ss);
739 let (rho, mu) = onion_utils::gen_rho_mu_from_shared_secret(onion_packet_ss.as_ref());
740 onion_packet_keys.push(onion_utils::OnionKeys {
742 shared_secret: onion_packet_ss,
744 blinding_factor: [0; 32],
752 if let Some(control_tlvs) = final_control_tlvs {
753 payloads.push((Payload::Receive {
755 reply_path: reply_path.take(),
757 }, prev_control_tlvs_ss.unwrap()));
759 payloads.push((Payload::Receive {
760 control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id: None, }),
761 reply_path: reply_path.take(),
763 }, prev_control_tlvs_ss.unwrap()));
766 Ok((payloads, onion_packet_keys))
769 /// Errors if the serialized payload size exceeds onion_message::BIG_PACKET_HOP_DATA_LEN
770 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, ()> {
772 // "`len` allows larger messages to be sent than the standard 1300 bytes allowed for an HTLC
773 // onion, but this should be used sparingly as it is reduces anonymity set, hence the
774 // recommendation that it either look like an HTLC onion, or if larger, be a fixed size."
775 let payloads_ser_len = onion_utils::payloads_serialized_length(&payloads);
776 let hop_data_len = if payloads_ser_len <= SMALL_PACKET_HOP_DATA_LEN {
777 SMALL_PACKET_HOP_DATA_LEN
778 } else if payloads_ser_len <= BIG_PACKET_HOP_DATA_LEN {
779 BIG_PACKET_HOP_DATA_LEN
780 } else { return Err(()) };
782 onion_utils::construct_onion_message_packet::<_, _>(
783 payloads, onion_keys, prng_seed, hop_data_len)