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, SocketAddress};
26 use crate::ln::onion_utils;
27 use crate::ln::peer_handler::IgnoringMessageHandler;
28 use crate::routing::gossip::{NetworkGraph, NodeId};
29 pub use super::packet::OnionMessageContents;
30 use super::packet::ParsedOnionMessageContents;
31 use super::offers::OffersMessageHandler;
32 use super::packet::{BIG_PACKET_HOP_DATA_LEN, ForwardControlTlvs, Packet, Payload, ReceiveControlTlvs, SMALL_PACKET_HOP_DATA_LEN};
33 use crate::util::logger::Logger;
34 use crate::util::ser::Writeable;
39 use crate::sync::{Arc, Mutex};
40 use crate::prelude::*;
42 /// A sender, receiver and forwarder of [`OnionMessage`]s.
44 /// # Handling Messages
46 /// `OnionMessenger` implements [`OnionMessageHandler`], making it responsible for either forwarding
47 /// messages to peers or delegating to the appropriate handler for the message type. Currently, the
48 /// available handlers are:
49 /// * [`OffersMessageHandler`], for responding to [`InvoiceRequest`]s and paying [`Bolt12Invoice`]s
50 /// * [`CustomOnionMessageHandler`], for handling user-defined message types
52 /// # Sending Messages
54 /// [`OnionMessage`]s are sent initially using [`OnionMessenger::send_onion_message`]. When handling
55 /// a message, the matched handler may return a response message which `OnionMessenger` will send
61 /// # extern crate bitcoin;
62 /// # use bitcoin::hashes::_export::_core::time::Duration;
63 /// # use bitcoin::hashes::hex::FromHex;
64 /// # use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey};
65 /// # use lightning::blinded_path::BlindedPath;
66 /// # use lightning::sign::KeysManager;
67 /// # use lightning::ln::peer_handler::IgnoringMessageHandler;
68 /// # use lightning::onion_message::{OnionMessageContents, Destination, MessageRouter, OnionMessagePath, OnionMessenger};
69 /// # use lightning::util::logger::{Logger, Record};
70 /// # use lightning::util::ser::{Writeable, Writer};
71 /// # use lightning::io;
72 /// # use std::sync::Arc;
73 /// # struct FakeLogger;
74 /// # impl Logger for FakeLogger {
75 /// # fn log(&self, record: Record) { println!("{:?}" , record); }
77 /// # struct FakeMessageRouter {}
78 /// # impl MessageRouter for FakeMessageRouter {
79 /// # fn find_path(&self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination) -> Result<OnionMessagePath, ()> {
80 /// # let secp_ctx = Secp256k1::new();
81 /// # let node_secret = SecretKey::from_slice(&<Vec<u8>>::from_hex("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
82 /// # let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
83 /// # let hop_node_id2 = hop_node_id1;
84 /// # Ok(OnionMessagePath {
85 /// # intermediate_nodes: vec![hop_node_id1, hop_node_id2],
87 /// # addresses: None,
91 /// # let seed = [42u8; 32];
92 /// # let time = Duration::from_secs(123456);
93 /// # let keys_manager = KeysManager::new(&seed, time.as_secs(), time.subsec_nanos());
94 /// # let logger = Arc::new(FakeLogger {});
95 /// # let node_secret = SecretKey::from_slice(&<Vec<u8>>::from_hex("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
96 /// # let secp_ctx = Secp256k1::new();
97 /// # let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
98 /// # let (hop_node_id3, hop_node_id4) = (hop_node_id1, hop_node_id1);
99 /// # let destination_node_id = hop_node_id1;
100 /// # let message_router = Arc::new(FakeMessageRouter {});
101 /// # let custom_message_handler = IgnoringMessageHandler {};
102 /// # let offers_message_handler = IgnoringMessageHandler {};
103 /// // Create the onion messenger. This must use the same `keys_manager` as is passed to your
104 /// // ChannelManager.
105 /// let onion_messenger = OnionMessenger::new(
106 /// &keys_manager, &keys_manager, logger, message_router, &offers_message_handler,
107 /// &custom_message_handler
110 /// # #[derive(Debug)]
111 /// # struct YourCustomMessage {}
112 /// impl Writeable for YourCustomMessage {
113 /// fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
115 /// // Write your custom onion message to `w`
118 /// impl OnionMessageContents for YourCustomMessage {
119 /// fn tlv_type(&self) -> u64 {
120 /// # let your_custom_message_type = 42;
121 /// your_custom_message_type
124 /// // Send a custom onion message to a node id.
125 /// let destination = Destination::Node(destination_node_id);
126 /// let reply_path = None;
127 /// # let message = YourCustomMessage {};
128 /// onion_messenger.send_onion_message(message, destination, reply_path);
130 /// // Create a blinded path to yourself, for someone to send an onion message to.
131 /// # let your_node_id = hop_node_id1;
132 /// let hops = [hop_node_id3, hop_node_id4, your_node_id];
133 /// let blinded_path = BlindedPath::new_for_message(&hops, &keys_manager, &secp_ctx).unwrap();
135 /// // Send a custom onion message to a blinded path.
136 /// let destination = Destination::BlindedPath(blinded_path);
137 /// let reply_path = None;
138 /// # let message = YourCustomMessage {};
139 /// onion_messenger.send_onion_message(message, destination, reply_path);
142 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
143 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
144 pub struct OnionMessenger<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref>
146 ES::Target: EntropySource,
147 NS::Target: NodeSigner,
149 MR::Target: MessageRouter,
150 OMH::Target: OffersMessageHandler,
151 CMH:: Target: CustomOnionMessageHandler,
156 message_buffers: Mutex<HashMap<PublicKey, OnionMessageBuffer>>,
157 secp_ctx: Secp256k1<secp256k1::All>,
163 /// [`OnionMessage`]s buffered to be sent.
164 enum OnionMessageBuffer {
165 /// Messages for a node connected as a peer.
166 ConnectedPeer(VecDeque<OnionMessage>),
168 /// Messages for a node that is not yet connected.
169 PendingConnection(VecDeque<OnionMessage>),
172 impl OnionMessageBuffer {
173 fn pending_messages(&self) -> &VecDeque<OnionMessage> {
175 OnionMessageBuffer::ConnectedPeer(pending_messages) => pending_messages,
176 OnionMessageBuffer::PendingConnection(pending_messages) => pending_messages,
180 fn enqueue_message(&mut self, message: OnionMessage) {
181 let pending_messages = match self {
182 OnionMessageBuffer::ConnectedPeer(pending_messages) => pending_messages,
183 OnionMessageBuffer::PendingConnection(pending_messages) => pending_messages,
186 pending_messages.push_back(message);
189 fn dequeue_message(&mut self) -> Option<OnionMessage> {
190 let pending_messages = match self {
191 OnionMessageBuffer::ConnectedPeer(pending_messages) => pending_messages,
192 OnionMessageBuffer::PendingConnection(pending_messages) => {
193 debug_assert!(false);
198 pending_messages.pop_front()
202 fn release_pending_messages(&mut self) -> VecDeque<OnionMessage> {
203 let pending_messages = match self {
204 OnionMessageBuffer::ConnectedPeer(pending_messages) => pending_messages,
205 OnionMessageBuffer::PendingConnection(pending_messages) => pending_messages,
208 core::mem::take(pending_messages)
211 fn mark_connected(&mut self) {
212 if let OnionMessageBuffer::PendingConnection(pending_messages) = self {
213 let mut new_pending_messages = VecDeque::new();
214 core::mem::swap(pending_messages, &mut new_pending_messages);
215 *self = OnionMessageBuffer::ConnectedPeer(new_pending_messages);
220 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
222 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
223 /// enqueued for sending.
224 #[cfg(not(c_bindings))]
225 pub struct PendingOnionMessage<T: OnionMessageContents> {
226 /// The message contents to send in an [`OnionMessage`].
229 /// The destination of the message.
230 pub destination: Destination,
232 /// A reply path to include in the [`OnionMessage`] for a response.
233 pub reply_path: Option<BlindedPath>,
237 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
239 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
240 /// enqueued for sending.
241 pub type PendingOnionMessage<T: OnionMessageContents> = (T, Destination, Option<BlindedPath>);
243 pub(crate) fn new_pending_onion_message<T: OnionMessageContents>(
244 contents: T, destination: Destination, reply_path: Option<BlindedPath>
245 ) -> PendingOnionMessage<T> {
246 #[cfg(not(c_bindings))]
247 return PendingOnionMessage { contents, destination, reply_path };
249 return (contents, destination, reply_path);
252 /// A trait defining behavior for routing an [`OnionMessage`].
253 pub trait MessageRouter {
254 /// Returns a route for sending an [`OnionMessage`] to the given [`Destination`].
256 &self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
257 ) -> Result<OnionMessagePath, ()>;
260 /// A [`MessageRouter`] that can only route to a directly connected [`Destination`].
261 pub struct DefaultMessageRouter<G: Deref<Target=NetworkGraph<L>>, L: Deref>
268 impl<G: Deref<Target=NetworkGraph<L>>, L: Deref> DefaultMessageRouter<G, L>
272 /// Creates a [`DefaultMessageRouter`] using the given [`NetworkGraph`].
273 pub fn new(network_graph: G) -> Self {
274 Self { network_graph }
278 impl<G: Deref<Target=NetworkGraph<L>>, L: Deref> MessageRouter for DefaultMessageRouter<G, L>
283 &self, _sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
284 ) -> Result<OnionMessagePath, ()> {
285 let first_node = destination.first_node();
286 if peers.contains(&first_node) {
287 Ok(OnionMessagePath { intermediate_nodes: vec![], destination, addresses: None })
289 let network_graph = self.network_graph.deref().read_only();
290 let node_announcement = network_graph
291 .node(&NodeId::from_pubkey(&first_node))
292 .and_then(|node_info| node_info.announcement_info.as_ref())
293 .and_then(|announcement_info| announcement_info.announcement_message.as_ref())
294 .map(|node_announcement| &node_announcement.contents);
296 match node_announcement {
297 Some(node_announcement) if node_announcement.features.supports_onion_messages() => {
298 let addresses = Some(node_announcement.addresses.clone());
299 Ok(OnionMessagePath { intermediate_nodes: vec![], destination, addresses })
307 /// A path for sending an [`OnionMessage`].
309 pub struct OnionMessagePath {
310 /// Nodes on the path between the sender and the destination.
311 pub intermediate_nodes: Vec<PublicKey>,
313 /// The recipient of the message.
314 pub destination: Destination,
316 /// Addresses that may be used to connect to [`OnionMessagePath::first_node`].
318 /// Only needs to be set if a connection to the node is required. [`OnionMessenger`] may use
319 /// this to initiate such a connection.
320 pub addresses: Option<Vec<SocketAddress>>,
323 impl OnionMessagePath {
324 /// Returns the first node in the path.
325 pub fn first_node(&self) -> PublicKey {
326 self.intermediate_nodes
329 .unwrap_or_else(|| self.destination.first_node())
333 /// The destination of an onion message.
335 pub enum Destination {
336 /// We're sending this onion message to a node.
338 /// We're sending this onion message to a blinded path.
339 BlindedPath(BlindedPath),
343 pub(super) fn num_hops(&self) -> usize {
345 Destination::Node(_) => 1,
346 Destination::BlindedPath(BlindedPath { blinded_hops, .. }) => blinded_hops.len(),
350 fn first_node(&self) -> PublicKey {
352 Destination::Node(node_id) => *node_id,
353 Destination::BlindedPath(BlindedPath { introduction_node_id: node_id, .. }) => *node_id,
358 /// Result of successfully [sending an onion message].
360 /// [sending an onion message]: OnionMessenger::send_onion_message
361 #[derive(Debug, PartialEq, Eq)]
362 pub enum SendSuccess {
363 /// The message was buffered and will be sent once it is processed by
364 /// [`OnionMessageHandler::next_onion_message_for_peer`].
366 /// The message was buffered and will be sent once the node is connected as a peer and it is
367 /// processed by [`OnionMessageHandler::next_onion_message_for_peer`].
368 BufferedAwaitingConnection(PublicKey),
371 /// Errors that may occur when [sending an onion message].
373 /// [sending an onion message]: OnionMessenger::send_onion_message
374 #[derive(Debug, PartialEq, Eq)]
376 /// Errored computing onion message packet keys.
377 Secp256k1(secp256k1::Error),
378 /// Because implementations such as Eclair will drop onion messages where the message packet
379 /// exceeds 32834 bytes, we refuse to send messages where the packet exceeds this size.
381 /// The provided [`Destination`] was an invalid [`BlindedPath`] due to not having any blinded
384 /// A path from the sender to the destination could not be found by the [`MessageRouter`].
386 /// Onion message contents must have a TLV type >= 64.
388 /// Our next-hop peer's buffer was full or our total outbound buffer was full.
390 /// Failed to retrieve our node id from the provided [`NodeSigner`].
392 /// [`NodeSigner`]: crate::sign::NodeSigner
394 /// We attempted to send to a blinded path where we are the introduction node, and failed to
395 /// advance the blinded path to make the second hop the new introduction node. Either
396 /// [`NodeSigner::ecdh`] failed, we failed to tweak the current blinding point to get the
397 /// new blinding point, or we were attempting to send to ourselves.
398 BlindedPathAdvanceFailed,
401 /// Handler for custom onion messages. If you are using [`SimpleArcOnionMessenger`],
402 /// [`SimpleRefOnionMessenger`], or prefer to ignore inbound custom onion messages,
403 /// [`IgnoringMessageHandler`] must be provided to [`OnionMessenger::new`]. Otherwise, a custom
404 /// implementation of this trait must be provided, with [`CustomMessage`] specifying the supported
407 /// See [`OnionMessenger`] for example usage.
409 /// [`IgnoringMessageHandler`]: crate::ln::peer_handler::IgnoringMessageHandler
410 /// [`CustomMessage`]: Self::CustomMessage
411 pub trait CustomOnionMessageHandler {
412 /// The message known to the handler. To support multiple message types, you may want to make this
413 /// an enum with a variant for each supported message.
414 type CustomMessage: OnionMessageContents;
416 /// Called with the custom message that was received, returning a response to send, if any.
418 /// The returned [`Self::CustomMessage`], if any, is enqueued to be sent by [`OnionMessenger`].
419 fn handle_custom_message(&self, msg: Self::CustomMessage) -> Option<Self::CustomMessage>;
421 /// Read a custom message of type `message_type` from `buffer`, returning `Ok(None)` if the
422 /// message type is unknown.
423 fn read_custom_message<R: io::Read>(&self, message_type: u64, buffer: &mut R) -> Result<Option<Self::CustomMessage>, msgs::DecodeError>;
425 /// Releases any [`Self::CustomMessage`]s that need to be sent.
427 /// Typically, this is used for messages initiating a message flow rather than in response to
428 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
429 #[cfg(not(c_bindings))]
430 fn release_pending_custom_messages(&self) -> Vec<PendingOnionMessage<Self::CustomMessage>>;
432 /// Releases any [`Self::CustomMessage`]s that need to be sent.
434 /// Typically, this is used for messages initiating a message flow rather than in response to
435 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
437 fn release_pending_custom_messages(&self) -> Vec<(Self::CustomMessage, Destination, Option<BlindedPath>)>;
440 /// A processed incoming onion message, containing either a Forward (another onion message)
441 /// or a Receive payload with decrypted contents.
442 pub enum PeeledOnion<T: OnionMessageContents> {
443 /// Forwarded onion, with the next node id and a new onion
444 Forward(PublicKey, OnionMessage),
445 /// Received onion message, with decrypted contents, path_id, and reply path
446 Receive(ParsedOnionMessageContents<T>, Option<[u8; 32]>, Option<BlindedPath>)
449 /// Creates an [`OnionMessage`] with the given `contents` for sending to the destination of
452 /// Returns both the node id of the peer to send the message to and the message itself.
453 pub fn create_onion_message<ES: Deref, NS: Deref, T: OnionMessageContents>(
454 entropy_source: &ES, node_signer: &NS, secp_ctx: &Secp256k1<secp256k1::All>,
455 path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
456 ) -> Result<(PublicKey, OnionMessage), SendError>
458 ES::Target: EntropySource,
459 NS::Target: NodeSigner,
461 let OnionMessagePath { intermediate_nodes, mut destination, .. } = path;
462 if let Destination::BlindedPath(BlindedPath { ref blinded_hops, .. }) = destination {
463 if blinded_hops.is_empty() {
464 return Err(SendError::TooFewBlindedHops);
468 if contents.tlv_type() < 64 { return Err(SendError::InvalidMessage) }
470 // If we are sending straight to a blinded path and we are the introduction node, we need to
471 // advance the blinded path by 1 hop so the second hop is the new introduction node.
472 if intermediate_nodes.len() == 0 {
473 if let Destination::BlindedPath(ref mut blinded_path) = destination {
474 let our_node_id = node_signer.get_node_id(Recipient::Node)
475 .map_err(|()| SendError::GetNodeIdFailed)?;
476 if blinded_path.introduction_node_id == our_node_id {
477 advance_path_by_one(blinded_path, node_signer, &secp_ctx)
478 .map_err(|()| SendError::BlindedPathAdvanceFailed)?;
483 let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
484 let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
485 let (first_node_id, blinding_point) = if let Some(first_node_id) = intermediate_nodes.first() {
486 (*first_node_id, PublicKey::from_secret_key(&secp_ctx, &blinding_secret))
489 Destination::Node(pk) => (pk, PublicKey::from_secret_key(&secp_ctx, &blinding_secret)),
490 Destination::BlindedPath(BlindedPath { introduction_node_id, blinding_point, .. }) =>
491 (introduction_node_id, blinding_point),
494 let (packet_payloads, packet_keys) = packet_payloads_and_keys(
495 &secp_ctx, &intermediate_nodes, destination, contents, reply_path, &blinding_secret)
496 .map_err(|e| SendError::Secp256k1(e))?;
498 let prng_seed = entropy_source.get_secure_random_bytes();
499 let onion_routing_packet = construct_onion_message_packet(
500 packet_payloads, packet_keys, prng_seed).map_err(|()| SendError::TooBigPacket)?;
502 Ok((first_node_id, OnionMessage {
508 /// Decode one layer of an incoming [`OnionMessage`].
510 /// Returns either the next layer of the onion for forwarding or the decrypted content for the
512 pub fn peel_onion_message<NS: Deref, L: Deref, CMH: Deref>(
513 msg: &OnionMessage, secp_ctx: &Secp256k1<secp256k1::All>, node_signer: NS, logger: L,
515 ) -> Result<PeeledOnion<<<CMH>::Target as CustomOnionMessageHandler>::CustomMessage>, ()>
517 NS::Target: NodeSigner,
519 CMH::Target: CustomOnionMessageHandler,
521 let control_tlvs_ss = match node_signer.ecdh(Recipient::Node, &msg.blinding_point, None) {
524 log_error!(logger, "Failed to retrieve node secret: {:?}", e);
528 let onion_decode_ss = {
529 let blinding_factor = {
530 let mut hmac = HmacEngine::<Sha256>::new(b"blinded_node_id");
531 hmac.input(control_tlvs_ss.as_ref());
532 Hmac::from_engine(hmac).to_byte_array()
534 match node_signer.ecdh(Recipient::Node, &msg.onion_routing_packet.public_key,
535 Some(&Scalar::from_be_bytes(blinding_factor).unwrap()))
537 Ok(ss) => ss.secret_bytes(),
539 log_trace!(logger, "Failed to compute onion packet shared secret");
544 match onion_utils::decode_next_untagged_hop(
545 onion_decode_ss, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
546 (control_tlvs_ss, custom_handler.deref(), logger.deref())
548 Ok((Payload::Receive::<ParsedOnionMessageContents<<<CMH as Deref>::Target as CustomOnionMessageHandler>::CustomMessage>> {
549 message, control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id }), reply_path,
551 Ok(PeeledOnion::Receive(message, path_id, reply_path))
553 Ok((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
554 next_node_id, next_blinding_override
555 })), Some((next_hop_hmac, new_packet_bytes)))) => {
556 // TODO: we need to check whether `next_node_id` is our node, in which case this is a dummy
557 // blinded hop and this onion message is destined for us. In this situation, we should keep
558 // unwrapping the onion layers to get to the final payload. Since we don't have the option
559 // of creating blinded paths with dummy hops currently, we should be ok to not handle this
561 let new_pubkey = match onion_utils::next_hop_pubkey(&secp_ctx, msg.onion_routing_packet.public_key, &onion_decode_ss) {
564 log_trace!(logger, "Failed to compute next hop packet pubkey: {}", e);
568 let outgoing_packet = Packet {
570 public_key: new_pubkey,
571 hop_data: new_packet_bytes,
574 let onion_message = OnionMessage {
575 blinding_point: match next_blinding_override {
576 Some(blinding_point) => blinding_point,
578 match onion_utils::next_hop_pubkey(
579 &secp_ctx, msg.blinding_point, control_tlvs_ss.as_ref()
583 log_trace!(logger, "Failed to compute next blinding point: {}", e);
589 onion_routing_packet: outgoing_packet,
592 Ok(PeeledOnion::Forward(next_node_id, onion_message))
595 log_trace!(logger, "Errored decoding onion message packet: {:?}", e);
599 log_trace!(logger, "Received bogus onion message packet, either the sender encoded a final hop as a forwarding hop or vice versa");
605 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref>
606 OnionMessenger<ES, NS, L, MR, OMH, CMH>
608 ES::Target: EntropySource,
609 NS::Target: NodeSigner,
611 MR::Target: MessageRouter,
612 OMH::Target: OffersMessageHandler,
613 CMH::Target: CustomOnionMessageHandler,
615 /// Constructs a new `OnionMessenger` to send, forward, and delegate received onion messages to
616 /// their respective handlers.
618 entropy_source: ES, node_signer: NS, logger: L, message_router: MR, offers_handler: OMH,
621 let mut secp_ctx = Secp256k1::new();
622 secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
626 message_buffers: Mutex::new(HashMap::new()),
635 /// Sends an [`OnionMessage`] with the given `contents` to `destination`.
637 /// See [`OnionMessenger`] for example usage.
638 pub fn send_onion_message<T: OnionMessageContents>(
639 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>
640 ) -> Result<SendSuccess, SendError> {
641 self.find_path_and_enqueue_onion_message(
642 contents, destination, reply_path, format_args!("")
646 fn find_path_and_enqueue_onion_message<T: OnionMessageContents>(
647 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>,
648 log_suffix: fmt::Arguments
649 ) -> Result<SendSuccess, SendError> {
650 let result = self.find_path(destination)
651 .and_then(|path| self.enqueue_onion_message(path, contents, reply_path, log_suffix));
653 match result.as_ref() {
654 Err(SendError::GetNodeIdFailed) => {
655 log_warn!(self.logger, "Unable to retrieve node id {}", log_suffix);
657 Err(SendError::PathNotFound) => {
658 log_trace!(self.logger, "Failed to find path {}", log_suffix);
661 log_trace!(self.logger, "Failed sending onion message {}: {:?}", log_suffix, e);
663 Ok(SendSuccess::Buffered) => {
664 log_trace!(self.logger, "Buffered onion message {}", log_suffix);
666 Ok(SendSuccess::BufferedAwaitingConnection(node_id)) => {
668 self.logger, "Buffered onion message waiting on peer connection {}: {:?}",
677 fn find_path(&self, destination: Destination) -> Result<OnionMessagePath, SendError> {
678 let sender = self.node_signer
679 .get_node_id(Recipient::Node)
680 .map_err(|_| SendError::GetNodeIdFailed)?;
682 let peers = self.message_buffers.lock().unwrap()
684 .filter(|(_, buffer)| matches!(buffer, OnionMessageBuffer::ConnectedPeer(_)))
685 .map(|(node_id, _)| *node_id)
689 .find_path(sender, peers, destination)
690 .map_err(|_| SendError::PathNotFound)
693 fn enqueue_onion_message<T: OnionMessageContents>(
694 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
695 log_suffix: fmt::Arguments
696 ) -> Result<SendSuccess, SendError> {
697 log_trace!(self.logger, "Constructing onion message {}: {:?}", log_suffix, contents);
699 let (first_node_id, onion_message) = create_onion_message(
700 &self.entropy_source, &self.node_signer, &self.secp_ctx, path, contents, reply_path
703 let mut message_buffers = self.message_buffers.lock().unwrap();
704 if outbound_buffer_full(&first_node_id, &message_buffers) {
705 return Err(SendError::BufferFull);
708 match message_buffers.entry(first_node_id) {
709 hash_map::Entry::Vacant(e) => {
710 e.insert(OnionMessageBuffer::PendingConnection(VecDeque::new()))
711 .enqueue_message(onion_message);
712 Ok(SendSuccess::BufferedAwaitingConnection(first_node_id))
714 hash_map::Entry::Occupied(mut e) => {
715 e.get_mut().enqueue_message(onion_message);
716 Ok(SendSuccess::Buffered)
722 pub(super) fn send_onion_message_using_path<T: OnionMessageContents>(
723 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>
724 ) -> Result<SendSuccess, SendError> {
725 self.enqueue_onion_message(path, contents, reply_path, format_args!(""))
728 fn handle_onion_message_response<T: OnionMessageContents>(
729 &self, response: Option<T>, reply_path: Option<BlindedPath>, log_suffix: fmt::Arguments
731 if let Some(response) = response {
733 Some(reply_path) => {
734 let _ = self.find_path_and_enqueue_onion_message(
735 response, Destination::BlindedPath(reply_path), None, log_suffix
739 log_trace!(self.logger, "Missing reply path {}", log_suffix);
746 pub(super) fn release_pending_msgs(&self) -> HashMap<PublicKey, VecDeque<OnionMessage>> {
747 let mut message_buffers = self.message_buffers.lock().unwrap();
748 let mut msgs = HashMap::new();
749 // We don't want to disconnect the peers by removing them entirely from the original map, so we
750 // release the pending message buffers individually.
751 for (peer_node_id, buffer) in &mut *message_buffers {
752 msgs.insert(*peer_node_id, buffer.release_pending_messages());
758 fn outbound_buffer_full(peer_node_id: &PublicKey, buffer: &HashMap<PublicKey, OnionMessageBuffer>) -> bool {
759 const MAX_TOTAL_BUFFER_SIZE: usize = (1 << 20) * 128;
760 const MAX_PER_PEER_BUFFER_SIZE: usize = (1 << 10) * 256;
761 let mut total_buffered_bytes = 0;
762 let mut peer_buffered_bytes = 0;
763 for (pk, peer_buf) in buffer {
764 for om in peer_buf.pending_messages() {
765 let om_len = om.serialized_length();
766 if pk == peer_node_id {
767 peer_buffered_bytes += om_len;
769 total_buffered_bytes += om_len;
771 if total_buffered_bytes >= MAX_TOTAL_BUFFER_SIZE ||
772 peer_buffered_bytes >= MAX_PER_PEER_BUFFER_SIZE
781 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref> OnionMessageHandler
782 for OnionMessenger<ES, NS, L, MR, OMH, CMH>
784 ES::Target: EntropySource,
785 NS::Target: NodeSigner,
787 MR::Target: MessageRouter,
788 OMH::Target: OffersMessageHandler,
789 CMH::Target: CustomOnionMessageHandler,
791 fn handle_onion_message(&self, _peer_node_id: &PublicKey, msg: &OnionMessage) {
792 match peel_onion_message(
793 msg, &self.secp_ctx, &*self.node_signer, &*self.logger, &*self.custom_handler
795 Ok(PeeledOnion::Receive(message, path_id, reply_path)) => {
798 "Received an onion message with path_id {:02x?} and {} reply_path: {:?}",
799 path_id, if reply_path.is_some() { "a" } else { "no" }, message);
802 ParsedOnionMessageContents::Offers(msg) => {
803 let response = self.offers_handler.handle_message(msg);
804 self.handle_onion_message_response(
805 response, reply_path, format_args!(
806 "when responding to Offers onion message with path_id {:02x?}",
811 ParsedOnionMessageContents::Custom(msg) => {
812 let response = self.custom_handler.handle_custom_message(msg);
813 self.handle_onion_message_response(
814 response, reply_path, format_args!(
815 "when responding to Custom onion message with path_id {:02x?}",
822 Ok(PeeledOnion::Forward(next_node_id, onion_message)) => {
823 let mut message_buffers = self.message_buffers.lock().unwrap();
824 if outbound_buffer_full(&next_node_id, &message_buffers) {
825 log_trace!(self.logger, "Dropping forwarded onion message to peer {:?}: outbound buffer full", next_node_id);
832 .or_insert_with(|| OnionMessageBuffer::ConnectedPeer(VecDeque::new()));
834 match message_buffers.entry(next_node_id) {
835 hash_map::Entry::Occupied(mut e) if matches!(
836 e.get(), OnionMessageBuffer::ConnectedPeer(..)
838 e.get_mut().enqueue_message(onion_message);
839 log_trace!(self.logger, "Forwarding an onion message to peer {}", next_node_id);
842 log_trace!(self.logger, "Dropping forwarded onion message to disconnected peer {:?}", next_node_id);
848 log_error!(self.logger, "Failed to process onion message {:?}", e);
853 fn peer_connected(&self, their_node_id: &PublicKey, init: &msgs::Init, _inbound: bool) -> Result<(), ()> {
854 if init.features.supports_onion_messages() {
855 self.message_buffers.lock().unwrap()
856 .entry(*their_node_id)
857 .or_insert_with(|| OnionMessageBuffer::ConnectedPeer(VecDeque::new()))
860 self.message_buffers.lock().unwrap().remove(their_node_id);
866 fn peer_disconnected(&self, their_node_id: &PublicKey) {
867 match self.message_buffers.lock().unwrap().remove(their_node_id) {
868 Some(OnionMessageBuffer::ConnectedPeer(..)) => {},
869 _ => debug_assert!(false),
873 fn provided_node_features(&self) -> NodeFeatures {
874 let mut features = NodeFeatures::empty();
875 features.set_onion_messages_optional();
879 fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
880 let mut features = InitFeatures::empty();
881 features.set_onion_messages_optional();
885 // Before returning any messages to send for the peer, this method will see if any messages were
886 // enqueued in the handler by users, find a path to the corresponding blinded path's introduction
887 // node, and then enqueue the message for sending to the first peer in the full path.
888 fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<OnionMessage> {
889 // Enqueue any initiating `OffersMessage`s to send.
890 for message in self.offers_handler.release_pending_messages() {
891 #[cfg(not(c_bindings))]
892 let PendingOnionMessage { contents, destination, reply_path } = message;
894 let (contents, destination, reply_path) = message;
895 let _ = self.find_path_and_enqueue_onion_message(
896 contents, destination, reply_path, format_args!("when sending OffersMessage")
900 // Enqueue any initiating `CustomMessage`s to send.
901 for message in self.custom_handler.release_pending_custom_messages() {
902 #[cfg(not(c_bindings))]
903 let PendingOnionMessage { contents, destination, reply_path } = message;
905 let (contents, destination, reply_path) = message;
906 let _ = self.find_path_and_enqueue_onion_message(
907 contents, destination, reply_path, format_args!("when sending CustomMessage")
911 self.message_buffers.lock().unwrap()
912 .get_mut(&peer_node_id)
913 .and_then(|buffer| buffer.dequeue_message())
917 // TODO: parameterize the below Simple* types with OnionMessenger and handle the messages it
919 /// Useful for simplifying the parameters of [`SimpleArcChannelManager`] and
920 /// [`SimpleArcPeerManager`]. See their docs for more details.
922 /// This is not exported to bindings users as type aliases aren't supported in most languages.
924 /// [`SimpleArcChannelManager`]: crate::ln::channelmanager::SimpleArcChannelManager
925 /// [`SimpleArcPeerManager`]: crate::ln::peer_handler::SimpleArcPeerManager
926 #[cfg(not(c_bindings))]
927 pub type SimpleArcOnionMessenger<M, T, F, L> = OnionMessenger<
931 Arc<DefaultMessageRouter<Arc<NetworkGraph<Arc<L>>>, Arc<L>>>,
932 Arc<SimpleArcChannelManager<M, T, F, L>>,
933 IgnoringMessageHandler
936 /// Useful for simplifying the parameters of [`SimpleRefChannelManager`] and
937 /// [`SimpleRefPeerManager`]. See their docs for more details.
939 /// This is not exported to bindings users as type aliases aren't supported in most languages.
941 /// [`SimpleRefChannelManager`]: crate::ln::channelmanager::SimpleRefChannelManager
942 /// [`SimpleRefPeerManager`]: crate::ln::peer_handler::SimpleRefPeerManager
943 #[cfg(not(c_bindings))]
944 pub type SimpleRefOnionMessenger<
945 'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, 'i, 'j, M, T, F, L
950 &'i DefaultMessageRouter<&'g NetworkGraph<&'b L>, &'b L>,
951 &'j SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, M, T, F, L>,
952 IgnoringMessageHandler
955 /// Construct onion packet payloads and keys for sending an onion message along the given
956 /// `unblinded_path` to the given `destination`.
957 fn packet_payloads_and_keys<T: OnionMessageContents, S: secp256k1::Signing + secp256k1::Verification>(
958 secp_ctx: &Secp256k1<S>, unblinded_path: &[PublicKey], destination: Destination, message: T,
959 mut reply_path: Option<BlindedPath>, session_priv: &SecretKey
960 ) -> Result<(Vec<(Payload<T>, [u8; 32])>, Vec<onion_utils::OnionKeys>), secp256k1::Error> {
961 let num_hops = unblinded_path.len() + destination.num_hops();
962 let mut payloads = Vec::with_capacity(num_hops);
963 let mut onion_packet_keys = Vec::with_capacity(num_hops);
965 let (mut intro_node_id_blinding_pt, num_blinded_hops) = if let Destination::BlindedPath(BlindedPath {
966 introduction_node_id, blinding_point, blinded_hops }) = &destination {
967 (Some((*introduction_node_id, *blinding_point)), blinded_hops.len()) } else { (None, 0) };
968 let num_unblinded_hops = num_hops - num_blinded_hops;
970 let mut unblinded_path_idx = 0;
971 let mut blinded_path_idx = 0;
972 let mut prev_control_tlvs_ss = None;
973 let mut final_control_tlvs = None;
974 utils::construct_keys_callback(secp_ctx, unblinded_path.iter(), Some(destination), session_priv,
975 |_, onion_packet_ss, ephemeral_pubkey, control_tlvs_ss, unblinded_pk_opt, enc_payload_opt| {
976 if num_unblinded_hops != 0 && unblinded_path_idx < num_unblinded_hops {
977 if let Some(ss) = prev_control_tlvs_ss.take() {
978 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(
980 next_node_id: unblinded_pk_opt.unwrap(),
981 next_blinding_override: None,
985 prev_control_tlvs_ss = Some(control_tlvs_ss);
986 unblinded_path_idx += 1;
987 } else if let Some((intro_node_id, blinding_pt)) = intro_node_id_blinding_pt.take() {
988 if let Some(control_tlvs_ss) = prev_control_tlvs_ss.take() {
989 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
990 next_node_id: intro_node_id,
991 next_blinding_override: Some(blinding_pt),
992 })), control_tlvs_ss));
995 if blinded_path_idx < num_blinded_hops.saturating_sub(1) && enc_payload_opt.is_some() {
996 payloads.push((Payload::Forward(ForwardControlTlvs::Blinded(enc_payload_opt.unwrap())),
998 blinded_path_idx += 1;
999 } else if let Some(encrypted_payload) = enc_payload_opt {
1000 final_control_tlvs = Some(ReceiveControlTlvs::Blinded(encrypted_payload));
1001 prev_control_tlvs_ss = Some(control_tlvs_ss);
1004 let (rho, mu) = onion_utils::gen_rho_mu_from_shared_secret(onion_packet_ss.as_ref());
1005 onion_packet_keys.push(onion_utils::OnionKeys {
1007 shared_secret: onion_packet_ss,
1009 blinding_factor: [0; 32],
1017 if let Some(control_tlvs) = final_control_tlvs {
1018 payloads.push((Payload::Receive {
1020 reply_path: reply_path.take(),
1022 }, prev_control_tlvs_ss.unwrap()));
1024 payloads.push((Payload::Receive {
1025 control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id: None, }),
1026 reply_path: reply_path.take(),
1028 }, prev_control_tlvs_ss.unwrap()));
1031 Ok((payloads, onion_packet_keys))
1034 /// Errors if the serialized payload size exceeds onion_message::BIG_PACKET_HOP_DATA_LEN
1035 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, ()> {
1037 // "`len` allows larger messages to be sent than the standard 1300 bytes allowed for an HTLC
1038 // onion, but this should be used sparingly as it is reduces anonymity set, hence the
1039 // recommendation that it either look like an HTLC onion, or if larger, be a fixed size."
1040 let payloads_ser_len = onion_utils::payloads_serialized_length(&payloads);
1041 let hop_data_len = if payloads_ser_len <= SMALL_PACKET_HOP_DATA_LEN {
1042 SMALL_PACKET_HOP_DATA_LEN
1043 } else if payloads_ser_len <= BIG_PACKET_HOP_DATA_LEN {
1044 BIG_PACKET_HOP_DATA_LEN
1045 } else { return Err(()) };
1047 onion_utils::construct_onion_message_packet::<_, _>(
1048 payloads, onion_keys, prng_seed, hop_data_len)