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::{CustomOnionMessageContents, ParsedOnionMessageContents};
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;
35 use crate::sync::{Arc, Mutex};
36 use crate::prelude::*;
38 /// A sender, receiver and forwarder of [`OnionMessage`]s.
40 /// # Handling Messages
42 /// `OnionMessenger` implements [`OnionMessageHandler`], making it responsible for either forwarding
43 /// messages to peers or delegating to the appropriate handler for the message type. Currently, the
44 /// available handlers are:
45 /// * [`OffersMessageHandler`], for responding to [`InvoiceRequest`]s and paying [`Bolt12Invoice`]s
46 /// * [`CustomOnionMessageHandler`], for handling user-defined message types
48 /// # Sending Messages
50 /// [`OnionMessage`]s are sent initially using [`OnionMessenger::send_onion_message`]. When handling
51 /// a message, the matched handler may return a response message which `OnionMessenger` will send
57 /// # extern crate bitcoin;
58 /// # use bitcoin::hashes::_export::_core::time::Duration;
59 /// # use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey};
60 /// # use lightning::blinded_path::BlindedPath;
61 /// # use lightning::sign::KeysManager;
62 /// # use lightning::ln::peer_handler::IgnoringMessageHandler;
63 /// # use lightning::onion_message::{CustomOnionMessageContents, Destination, MessageRouter, ParsedOnionMessageContents, OnionMessagePath, OnionMessenger};
64 /// # use lightning::util::logger::{Logger, Record};
65 /// # use lightning::util::ser::{Writeable, Writer};
66 /// # use lightning::io;
67 /// # use std::sync::Arc;
68 /// # struct FakeLogger;
69 /// # impl Logger for FakeLogger {
70 /// # fn log(&self, record: &Record) { unimplemented!() }
72 /// # struct FakeMessageRouter {}
73 /// # impl MessageRouter for FakeMessageRouter {
74 /// # fn find_path(&self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination) -> Result<OnionMessagePath, ()> {
75 /// # unimplemented!()
78 /// # let seed = [42u8; 32];
79 /// # let time = Duration::from_secs(123456);
80 /// # let keys_manager = KeysManager::new(&seed, time.as_secs(), time.subsec_nanos());
81 /// # let logger = Arc::new(FakeLogger {});
82 /// # let node_secret = SecretKey::from_slice(&hex::decode("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
83 /// # let secp_ctx = Secp256k1::new();
84 /// # let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
85 /// # let (hop_node_id2, hop_node_id3, hop_node_id4) = (hop_node_id1, hop_node_id1, hop_node_id1);
86 /// # let destination_node_id = hop_node_id1;
87 /// # let message_router = Arc::new(FakeMessageRouter {});
88 /// # let custom_message_handler = IgnoringMessageHandler {};
89 /// # let offers_message_handler = IgnoringMessageHandler {};
90 /// // Create the onion messenger. This must use the same `keys_manager` as is passed to your
91 /// // ChannelManager.
92 /// let onion_messenger = OnionMessenger::new(
93 /// &keys_manager, &keys_manager, logger, message_router, &offers_message_handler,
94 /// &custom_message_handler
97 /// # struct YourCustomMessage {}
98 /// impl Writeable for YourCustomMessage {
99 /// fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
101 /// // Write your custom onion message to `w`
104 /// impl CustomOnionMessageContents for YourCustomMessage {
105 /// fn tlv_type(&self) -> u64 {
106 /// # let your_custom_message_type = 42;
107 /// your_custom_message_type
110 /// // Send a custom onion message to a node id.
111 /// let path = OnionMessagePath {
112 /// intermediate_nodes: vec![hop_node_id1, hop_node_id2],
113 /// destination: Destination::Node(destination_node_id),
115 /// let reply_path = None;
116 /// # let your_custom_message = YourCustomMessage {};
117 /// let message = ParsedOnionMessageContents::Custom(your_custom_message);
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 your_custom_message = YourCustomMessage {};
132 /// let message = ParsedOnionMessageContents::Custom(your_custom_message);
133 /// onion_messenger.send_onion_message(path, message, reply_path);
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<OnionMessage>>>,
151 secp_ctx: Secp256k1<secp256k1::All>,
157 /// A trait defining behavior for routing an [`OnionMessage`].
158 pub trait MessageRouter {
159 /// Returns a route for sending an [`OnionMessage`] to the given [`Destination`].
161 &self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
162 ) -> Result<OnionMessagePath, ()>;
165 /// A [`MessageRouter`] that always fails.
166 pub struct DefaultMessageRouter;
168 impl MessageRouter for DefaultMessageRouter {
170 &self, _sender: PublicKey, _peers: Vec<PublicKey>, _destination: Destination
171 ) -> Result<OnionMessagePath, ()> {
176 /// A path for sending an [`OnionMessage`].
178 pub struct OnionMessagePath {
179 /// Nodes on the path between the sender and the destination.
180 pub intermediate_nodes: Vec<PublicKey>,
182 /// The recipient of the message.
183 pub destination: Destination,
186 /// The destination of an onion message.
188 pub enum Destination {
189 /// We're sending this onion message to a node.
191 /// We're sending this onion message to a blinded path.
192 BlindedPath(BlindedPath),
196 pub(super) fn num_hops(&self) -> usize {
198 Destination::Node(_) => 1,
199 Destination::BlindedPath(BlindedPath { blinded_hops, .. }) => blinded_hops.len(),
204 /// Errors that may occur when [sending an onion message].
206 /// [sending an onion message]: OnionMessenger::send_onion_message
207 #[derive(Debug, PartialEq, Eq)]
209 /// Errored computing onion message packet keys.
210 Secp256k1(secp256k1::Error),
211 /// Because implementations such as Eclair will drop onion messages where the message packet
212 /// exceeds 32834 bytes, we refuse to send messages where the packet exceeds this size.
214 /// The provided [`Destination`] was an invalid [`BlindedPath`], due to having fewer than two
217 /// Our next-hop peer was offline or does not support onion message forwarding.
219 /// Onion message contents must have a TLV type >= 64.
221 /// Our next-hop peer's buffer was full or our total outbound buffer was full.
223 /// Failed to retrieve our node id from the provided [`NodeSigner`].
225 /// [`NodeSigner`]: crate::sign::NodeSigner
227 /// We attempted to send to a blinded path where we are the introduction node, and failed to
228 /// advance the blinded path to make the second hop the new introduction node. Either
229 /// [`NodeSigner::ecdh`] failed, we failed to tweak the current blinding point to get the
230 /// new blinding point, or we were attempting to send to ourselves.
231 BlindedPathAdvanceFailed,
234 /// Handler for custom onion messages. If you are using [`SimpleArcOnionMessenger`],
235 /// [`SimpleRefOnionMessenger`], or prefer to ignore inbound custom onion messages,
236 /// [`IgnoringMessageHandler`] must be provided to [`OnionMessenger::new`]. Otherwise, a custom
237 /// implementation of this trait must be provided, with [`CustomMessage`] specifying the supported
240 /// See [`OnionMessenger`] for example usage.
242 /// [`IgnoringMessageHandler`]: crate::ln::peer_handler::IgnoringMessageHandler
243 /// [`CustomMessage`]: Self::CustomMessage
244 pub trait CustomOnionMessageHandler {
245 /// The message known to the handler. To support multiple message types, you may want to make this
246 /// an enum with a variant for each supported message.
247 type CustomMessage: CustomOnionMessageContents;
249 /// Called with the custom message that was received, returning a response to send, if any.
250 fn handle_custom_message(&self, msg: Self::CustomMessage) -> Option<Self::CustomMessage>;
252 /// Read a custom message of type `message_type` from `buffer`, returning `Ok(None)` if the
253 /// message type is unknown.
254 fn read_custom_message<R: io::Read>(&self, message_type: u64, buffer: &mut R) -> Result<Option<Self::CustomMessage>, msgs::DecodeError>;
257 /// A processed incoming onion message, containing either a Forward (another onion message)
258 /// or a Receive payload with decrypted contents.
259 pub enum PeeledOnion<CM: CustomOnionMessageContents> {
260 /// Forwarded onion, with the next node id and a new onion
261 Forward(PublicKey, OnionMessage),
262 /// Received onion message, with decrypted contents, path_id, and reply path
263 Receive(ParsedOnionMessageContents<CM>, Option<[u8; 32]>, Option<BlindedPath>)
266 /// Creates an [`OnionMessage`] with the given `contents` for sending to the destination of
269 /// Returns both the node id of the peer to send the message to and the message itself.
270 pub fn create_onion_message<ES: Deref, NS: Deref, T: CustomOnionMessageContents>(
271 entropy_source: &ES, node_signer: &NS, secp_ctx: &Secp256k1<secp256k1::All>,
272 path: OnionMessagePath, contents: ParsedOnionMessageContents<T>,
273 reply_path: Option<BlindedPath>,
274 ) -> Result<(PublicKey, OnionMessage), SendError>
276 ES::Target: EntropySource,
277 NS::Target: NodeSigner,
279 let OnionMessagePath { intermediate_nodes, mut destination } = path;
280 if let Destination::BlindedPath(BlindedPath { ref blinded_hops, .. }) = destination {
281 if blinded_hops.len() < 2 {
282 return Err(SendError::TooFewBlindedHops);
286 if contents.tlv_type() < 64 { return Err(SendError::InvalidMessage) }
288 // If we are sending straight to a blinded path and we are the introduction node, we need to
289 // advance the blinded path by 1 hop so the second hop is the new introduction node.
290 if intermediate_nodes.len() == 0 {
291 if let Destination::BlindedPath(ref mut blinded_path) = destination {
292 let our_node_id = node_signer.get_node_id(Recipient::Node)
293 .map_err(|()| SendError::GetNodeIdFailed)?;
294 if blinded_path.introduction_node_id == our_node_id {
295 advance_path_by_one(blinded_path, node_signer, &secp_ctx)
296 .map_err(|()| SendError::BlindedPathAdvanceFailed)?;
301 let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
302 let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
303 let (first_node_id, blinding_point) = if let Some(first_node_id) = intermediate_nodes.first() {
304 (*first_node_id, PublicKey::from_secret_key(&secp_ctx, &blinding_secret))
307 Destination::Node(pk) => (pk, PublicKey::from_secret_key(&secp_ctx, &blinding_secret)),
308 Destination::BlindedPath(BlindedPath { introduction_node_id, blinding_point, .. }) =>
309 (introduction_node_id, blinding_point),
312 let (packet_payloads, packet_keys) = packet_payloads_and_keys(
313 &secp_ctx, &intermediate_nodes, destination, contents, reply_path, &blinding_secret)
314 .map_err(|e| SendError::Secp256k1(e))?;
316 let prng_seed = entropy_source.get_secure_random_bytes();
317 let onion_routing_packet = construct_onion_message_packet(
318 packet_payloads, packet_keys, prng_seed).map_err(|()| SendError::TooBigPacket)?;
320 Ok((first_node_id, OnionMessage {
326 /// Decode one layer of an incoming onion message
327 /// Returns either a Forward (another onion message), or Receive (decrypted content)
328 pub fn peel_onion<NS: Deref, L: Deref, CMH: Deref>(
329 node_signer: NS, secp_ctx: &Secp256k1<secp256k1::All>, logger: L, custom_handler: CMH,
331 ) -> Result<PeeledOnion<<<CMH>::Target as CustomOnionMessageHandler>::CustomMessage>, ()>
333 NS::Target: NodeSigner,
335 CMH::Target: CustomOnionMessageHandler,
337 let control_tlvs_ss = match node_signer.ecdh(Recipient::Node, &msg.blinding_point, None) {
340 log_error!(logger, "Failed to retrieve node secret: {:?}", e);
344 let onion_decode_ss = {
345 let blinding_factor = {
346 let mut hmac = HmacEngine::<Sha256>::new(b"blinded_node_id");
347 hmac.input(control_tlvs_ss.as_ref());
348 Hmac::from_engine(hmac).into_inner()
350 match node_signer.ecdh(Recipient::Node, &msg.onion_routing_packet.public_key,
351 Some(&Scalar::from_be_bytes(blinding_factor).unwrap()))
353 Ok(ss) => ss.secret_bytes(),
355 log_trace!(logger, "Failed to compute onion packet shared secret");
360 match onion_utils::decode_next_untagged_hop(
361 onion_decode_ss, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
362 (control_tlvs_ss, custom_handler.deref(), logger.deref())
364 Ok((Payload::Receive::<<<CMH as Deref>::Target as CustomOnionMessageHandler>::CustomMessage> {
365 message, control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id }), reply_path,
367 Ok(PeeledOnion::Receive(message, path_id, reply_path))
369 Ok((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
370 next_node_id, next_blinding_override
371 })), Some((next_hop_hmac, new_packet_bytes)))) => {
372 // TODO: we need to check whether `next_node_id` is our node, in which case this is a dummy
373 // blinded hop and this onion message is destined for us. In this situation, we should keep
374 // unwrapping the onion layers to get to the final payload. Since we don't have the option
375 // of creating blinded paths with dummy hops currently, we should be ok to not handle this
377 let new_pubkey = match onion_utils::next_hop_pubkey(&secp_ctx, msg.onion_routing_packet.public_key, &onion_decode_ss) {
380 log_trace!(logger, "Failed to compute next hop packet pubkey: {}", e);
384 let outgoing_packet = Packet {
386 public_key: new_pubkey,
387 hop_data: new_packet_bytes,
390 let onion_message = OnionMessage {
391 blinding_point: match next_blinding_override {
392 Some(blinding_point) => blinding_point,
394 match onion_utils::next_hop_pubkey(
395 &secp_ctx, msg.blinding_point, control_tlvs_ss.as_ref()
399 log_trace!(logger, "Failed to compute next blinding point: {}", e);
405 onion_routing_packet: outgoing_packet,
408 Ok(PeeledOnion::Forward(next_node_id, onion_message))
411 log_trace!(logger, "Errored decoding onion message packet: {:?}", e);
415 log_trace!(logger, "Received bogus onion message packet, either the sender encoded a final hop as a forwarding hop or vice versa");
421 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref>
422 OnionMessenger<ES, NS, L, MR, OMH, CMH>
424 ES::Target: EntropySource,
425 NS::Target: NodeSigner,
427 MR::Target: MessageRouter,
428 OMH::Target: OffersMessageHandler,
429 CMH::Target: CustomOnionMessageHandler,
431 /// Constructs a new `OnionMessenger` to send, forward, and delegate received onion messages to
432 /// their respective handlers.
434 entropy_source: ES, node_signer: NS, logger: L, message_router: MR, offers_handler: OMH,
437 let mut secp_ctx = Secp256k1::new();
438 secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
442 pending_messages: Mutex::new(HashMap::new()),
451 /// Sends an [`OnionMessage`] with the given `contents` for sending to the destination of
454 /// See [`OnionMessenger`] for example usage.
455 pub fn send_onion_message<T: CustomOnionMessageContents>(
456 &self, path: OnionMessagePath, contents: ParsedOnionMessageContents<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, path, contents, reply_path
463 let mut pending_per_peer_msgs = self.pending_messages.lock().unwrap();
464 if outbound_buffer_full(&first_node_id, &pending_per_peer_msgs) { return Err(SendError::BufferFull) }
465 match pending_per_peer_msgs.entry(first_node_id) {
466 hash_map::Entry::Vacant(_) => Err(SendError::InvalidFirstHop),
467 hash_map::Entry::Occupied(mut e) => {
468 e.get_mut().push_back(onion_msg);
474 fn find_path_and_enqueue_onion_message<T: CustomOnionMessageContents>(
475 &self, contents: ParsedOnionMessageContents<T>, destination: Destination,
476 log_suffix: fmt::Arguments
478 let sender = match self.node_signer.get_node_id(Recipient::Node) {
479 Ok(node_id) => node_id,
481 log_warn!(self.logger, "Unable to retrieve node id {}", log_suffix);
486 let peers = self.pending_messages.lock().unwrap().keys().copied().collect();
487 let path = match self.message_router.find_path(sender, peers, destination) {
490 log_trace!(self.logger, "Failed to find path {}", log_suffix);
495 log_trace!(self.logger, "Sending onion message {}", log_suffix);
497 if let Err(e) = self.send_onion_message(path, contents, None) {
498 log_trace!(self.logger, "Failed sending onion message {}: {:?}", log_suffix, e);
504 pub(super) fn release_pending_msgs(&self) -> HashMap<PublicKey, VecDeque<OnionMessage>> {
505 let mut pending_msgs = self.pending_messages.lock().unwrap();
506 let mut msgs = HashMap::new();
507 // We don't want to disconnect the peers by removing them entirely from the original map, so we
508 // swap the pending message buffers individually.
509 for (peer_node_id, pending_messages) in &mut *pending_msgs {
510 msgs.insert(*peer_node_id, core::mem::take(pending_messages));
516 fn outbound_buffer_full(peer_node_id: &PublicKey, buffer: &HashMap<PublicKey, VecDeque<OnionMessage>>) -> bool {
517 const MAX_TOTAL_BUFFER_SIZE: usize = (1 << 20) * 128;
518 const MAX_PER_PEER_BUFFER_SIZE: usize = (1 << 10) * 256;
519 let mut total_buffered_bytes = 0;
520 let mut peer_buffered_bytes = 0;
521 for (pk, peer_buf) in buffer {
523 let om_len = om.serialized_length();
524 if pk == peer_node_id {
525 peer_buffered_bytes += om_len;
527 total_buffered_bytes += om_len;
529 if total_buffered_bytes >= MAX_TOTAL_BUFFER_SIZE ||
530 peer_buffered_bytes >= MAX_PER_PEER_BUFFER_SIZE
539 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref> OnionMessageHandler
540 for OnionMessenger<ES, NS, L, MR, OMH, CMH>
542 ES::Target: EntropySource,
543 NS::Target: NodeSigner,
545 MR::Target: MessageRouter,
546 OMH::Target: OffersMessageHandler,
547 CMH::Target: CustomOnionMessageHandler,
549 /// Handle an incoming onion message. Currently, if a message was destined for us we will log, but
550 /// soon we'll delegate the onion message to a handler that can generate invoices or send
552 fn handle_onion_message(&self, _peer_node_id: &PublicKey, msg: &OnionMessage) {
554 &*self.node_signer, &self.secp_ctx, &*self.logger, &*self.custom_handler, msg
556 Ok(PeeledOnion::Receive(message, path_id, reply_path)) => {
557 log_trace!(self.logger,
558 "Received an onion message with path_id {:02x?} and {} reply_path",
559 path_id, if reply_path.is_some() { "a" } else { "no" });
560 let response = match message {
561 ParsedOnionMessageContents::Offers(msg) => {
562 self.offers_handler.handle_message(msg)
563 .map(|msg| ParsedOnionMessageContents::Offers(msg))
565 ParsedOnionMessageContents::Custom(msg) => {
566 self.custom_handler.handle_custom_message(msg)
567 .map(|msg| ParsedOnionMessageContents::Custom(msg))
570 if let Some(response) = response {
572 Some(reply_path) => {
573 self.find_path_and_enqueue_onion_message(
574 response, Destination::BlindedPath(reply_path), format_args!(
575 "when responding to onion message with path_id {:02x?}", path_id
582 "Missing reply path when responding to onion message with path_id {:02x?}",
589 Ok(PeeledOnion::Forward(next_node_id, onion_message)) => {
590 let mut pending_per_peer_msgs = self.pending_messages.lock().unwrap();
591 if outbound_buffer_full(&next_node_id, &pending_per_peer_msgs) {
592 log_trace!(self.logger, "Dropping forwarded onion message to peer {:?}: outbound buffer full", next_node_id);
597 pending_per_peer_msgs.entry(next_node_id).or_insert_with(VecDeque::new);
599 match pending_per_peer_msgs.entry(next_node_id) {
600 hash_map::Entry::Vacant(_) => {
601 log_trace!(self.logger, "Dropping forwarded onion message to disconnected peer {:?}", next_node_id);
604 hash_map::Entry::Occupied(mut e) => {
605 e.get_mut().push_back(onion_message);
606 log_trace!(self.logger, "Forwarding an onion message to peer {}", next_node_id);
611 log_error!(self.logger, "Failed to process onion message {:?}", e);
616 fn peer_connected(&self, their_node_id: &PublicKey, init: &msgs::Init, _inbound: bool) -> Result<(), ()> {
617 if init.features.supports_onion_messages() {
618 let mut peers = self.pending_messages.lock().unwrap();
619 peers.insert(their_node_id.clone(), VecDeque::new());
624 fn peer_disconnected(&self, their_node_id: &PublicKey) {
625 let mut pending_msgs = self.pending_messages.lock().unwrap();
626 pending_msgs.remove(their_node_id);
629 fn provided_node_features(&self) -> NodeFeatures {
630 let mut features = NodeFeatures::empty();
631 features.set_onion_messages_optional();
635 fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
636 let mut features = InitFeatures::empty();
637 features.set_onion_messages_optional();
641 fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<OnionMessage> {
642 let mut pending_msgs = self.pending_messages.lock().unwrap();
643 if let Some(msgs) = pending_msgs.get_mut(&peer_node_id) {
644 return msgs.pop_front()
650 // TODO: parameterize the below Simple* types with OnionMessenger and handle the messages it
652 /// Useful for simplifying the parameters of [`SimpleArcChannelManager`] and
653 /// [`SimpleArcPeerManager`]. See their docs for more details.
655 /// This is not exported to bindings users as `Arc`s don't make sense in bindings.
657 /// [`SimpleArcChannelManager`]: crate::ln::channelmanager::SimpleArcChannelManager
658 /// [`SimpleArcPeerManager`]: crate::ln::peer_handler::SimpleArcPeerManager
659 pub type SimpleArcOnionMessenger<L> = OnionMessenger<
663 Arc<DefaultMessageRouter>,
664 IgnoringMessageHandler,
665 IgnoringMessageHandler
668 /// Useful for simplifying the parameters of [`SimpleRefChannelManager`] and
669 /// [`SimpleRefPeerManager`]. See their docs for more details.
671 /// This is not exported to bindings users as general type aliases don't make sense in bindings.
673 /// [`SimpleRefChannelManager`]: crate::ln::channelmanager::SimpleRefChannelManager
674 /// [`SimpleRefPeerManager`]: crate::ln::peer_handler::SimpleRefPeerManager
675 pub type SimpleRefOnionMessenger<'a, 'b, 'c, L> = OnionMessenger<
679 &'c DefaultMessageRouter,
680 IgnoringMessageHandler,
681 IgnoringMessageHandler
684 /// Construct onion packet payloads and keys for sending an onion message along the given
685 /// `unblinded_path` to the given `destination`.
686 fn packet_payloads_and_keys<T: CustomOnionMessageContents, S: secp256k1::Signing + secp256k1::Verification>(
687 secp_ctx: &Secp256k1<S>, unblinded_path: &[PublicKey], destination: Destination,
688 message: ParsedOnionMessageContents<T>, mut reply_path: Option<BlindedPath>, session_priv: &SecretKey
689 ) -> Result<(Vec<(Payload<T>, [u8; 32])>, Vec<onion_utils::OnionKeys>), secp256k1::Error> {
690 let num_hops = unblinded_path.len() + destination.num_hops();
691 let mut payloads = Vec::with_capacity(num_hops);
692 let mut onion_packet_keys = Vec::with_capacity(num_hops);
694 let (mut intro_node_id_blinding_pt, num_blinded_hops) = if let Destination::BlindedPath(BlindedPath {
695 introduction_node_id, blinding_point, blinded_hops }) = &destination {
696 (Some((*introduction_node_id, *blinding_point)), blinded_hops.len()) } else { (None, 0) };
697 let num_unblinded_hops = num_hops - num_blinded_hops;
699 let mut unblinded_path_idx = 0;
700 let mut blinded_path_idx = 0;
701 let mut prev_control_tlvs_ss = None;
702 let mut final_control_tlvs = None;
703 utils::construct_keys_callback(secp_ctx, unblinded_path.iter(), Some(destination), session_priv,
704 |_, onion_packet_ss, ephemeral_pubkey, control_tlvs_ss, unblinded_pk_opt, enc_payload_opt| {
705 if num_unblinded_hops != 0 && unblinded_path_idx < num_unblinded_hops {
706 if let Some(ss) = prev_control_tlvs_ss.take() {
707 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(
709 next_node_id: unblinded_pk_opt.unwrap(),
710 next_blinding_override: None,
714 prev_control_tlvs_ss = Some(control_tlvs_ss);
715 unblinded_path_idx += 1;
716 } else if let Some((intro_node_id, blinding_pt)) = intro_node_id_blinding_pt.take() {
717 if let Some(control_tlvs_ss) = prev_control_tlvs_ss.take() {
718 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
719 next_node_id: intro_node_id,
720 next_blinding_override: Some(blinding_pt),
721 })), control_tlvs_ss));
724 if blinded_path_idx < num_blinded_hops.saturating_sub(1) && enc_payload_opt.is_some() {
725 payloads.push((Payload::Forward(ForwardControlTlvs::Blinded(enc_payload_opt.unwrap())),
727 blinded_path_idx += 1;
728 } else if let Some(encrypted_payload) = enc_payload_opt {
729 final_control_tlvs = Some(ReceiveControlTlvs::Blinded(encrypted_payload));
730 prev_control_tlvs_ss = Some(control_tlvs_ss);
733 let (rho, mu) = onion_utils::gen_rho_mu_from_shared_secret(onion_packet_ss.as_ref());
734 onion_packet_keys.push(onion_utils::OnionKeys {
736 shared_secret: onion_packet_ss,
738 blinding_factor: [0; 32],
746 if let Some(control_tlvs) = final_control_tlvs {
747 payloads.push((Payload::Receive {
749 reply_path: reply_path.take(),
751 }, prev_control_tlvs_ss.unwrap()));
753 payloads.push((Payload::Receive {
754 control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id: None, }),
755 reply_path: reply_path.take(),
757 }, prev_control_tlvs_ss.unwrap()));
760 Ok((payloads, onion_packet_keys))
763 /// Errors if the serialized payload size exceeds onion_message::BIG_PACKET_HOP_DATA_LEN
764 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, ()> {
766 // "`len` allows larger messages to be sent than the standard 1300 bytes allowed for an HTLC
767 // onion, but this should be used sparingly as it is reduces anonymity set, hence the
768 // recommendation that it either look like an HTLC onion, or if larger, be a fixed size."
769 let payloads_ser_len = onion_utils::payloads_serialized_length(&payloads);
770 let hop_data_len = if payloads_ser_len <= SMALL_PACKET_HOP_DATA_LEN {
771 SMALL_PACKET_HOP_DATA_LEN
772 } else if payloads_ser_len <= BIG_PACKET_HOP_DATA_LEN {
773 BIG_PACKET_HOP_DATA_LEN
774 } else { return Err(()) };
776 onion_utils::construct_onion_message_packet::<_, _>(
777 payloads, onion_keys, prng_seed, hop_data_len)