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::events::{Event, EventHandler, EventsProvider};
22 use crate::sign::{EntropySource, KeysManager, NodeSigner, Recipient};
23 #[cfg(not(c_bindings))]
24 use crate::ln::channelmanager::{SimpleArcChannelManager, SimpleRefChannelManager};
25 use crate::ln::features::{InitFeatures, NodeFeatures};
26 use crate::ln::msgs::{self, OnionMessage, OnionMessageHandler, SocketAddress};
27 use crate::ln::onion_utils;
28 use crate::ln::peer_handler::IgnoringMessageHandler;
29 use crate::routing::gossip::{NetworkGraph, NodeId};
30 pub use super::packet::OnionMessageContents;
31 use super::packet::ParsedOnionMessageContents;
32 use super::offers::OffersMessageHandler;
33 use super::packet::{BIG_PACKET_HOP_DATA_LEN, ForwardControlTlvs, Packet, Payload, ReceiveControlTlvs, SMALL_PACKET_HOP_DATA_LEN};
34 use crate::util::logger::Logger;
35 use crate::util::ser::Writeable;
40 use crate::sync::{Arc, Mutex};
41 use crate::prelude::*;
43 pub(super) const MAX_TIMER_TICKS: usize = 2;
45 /// A sender, receiver and forwarder of [`OnionMessage`]s.
47 /// # Handling Messages
49 /// `OnionMessenger` implements [`OnionMessageHandler`], making it responsible for either forwarding
50 /// messages to peers or delegating to the appropriate handler for the message type. Currently, the
51 /// available handlers are:
52 /// * [`OffersMessageHandler`], for responding to [`InvoiceRequest`]s and paying [`Bolt12Invoice`]s
53 /// * [`CustomOnionMessageHandler`], for handling user-defined message types
55 /// # Sending Messages
57 /// [`OnionMessage`]s are sent initially using [`OnionMessenger::send_onion_message`]. When handling
58 /// a message, the matched handler may return a response message which `OnionMessenger` will send
64 /// # extern crate bitcoin;
65 /// # use bitcoin::hashes::_export::_core::time::Duration;
66 /// # use bitcoin::hashes::hex::FromHex;
67 /// # use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey};
68 /// # use lightning::blinded_path::BlindedPath;
69 /// # use lightning::sign::KeysManager;
70 /// # use lightning::ln::peer_handler::IgnoringMessageHandler;
71 /// # use lightning::onion_message::{OnionMessageContents, Destination, MessageRouter, OnionMessagePath, OnionMessenger};
72 /// # use lightning::util::logger::{Logger, Record};
73 /// # use lightning::util::ser::{Writeable, Writer};
74 /// # use lightning::io;
75 /// # use std::sync::Arc;
76 /// # struct FakeLogger;
77 /// # impl Logger for FakeLogger {
78 /// # fn log(&self, record: Record) { println!("{:?}" , record); }
80 /// # struct FakeMessageRouter {}
81 /// # impl MessageRouter for FakeMessageRouter {
82 /// # fn find_path(&self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination) -> Result<OnionMessagePath, ()> {
83 /// # let secp_ctx = Secp256k1::new();
84 /// # let node_secret = SecretKey::from_slice(&<Vec<u8>>::from_hex("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
85 /// # let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
86 /// # let hop_node_id2 = hop_node_id1;
87 /// # Ok(OnionMessagePath {
88 /// # intermediate_nodes: vec![hop_node_id1, hop_node_id2],
90 /// # first_node_addresses: None,
94 /// # let seed = [42u8; 32];
95 /// # let time = Duration::from_secs(123456);
96 /// # let keys_manager = KeysManager::new(&seed, time.as_secs(), time.subsec_nanos());
97 /// # let logger = Arc::new(FakeLogger {});
98 /// # let node_secret = SecretKey::from_slice(&<Vec<u8>>::from_hex("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
99 /// # let secp_ctx = Secp256k1::new();
100 /// # let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
101 /// # let (hop_node_id3, hop_node_id4) = (hop_node_id1, hop_node_id1);
102 /// # let destination_node_id = hop_node_id1;
103 /// # let message_router = Arc::new(FakeMessageRouter {});
104 /// # let custom_message_handler = IgnoringMessageHandler {};
105 /// # let offers_message_handler = IgnoringMessageHandler {};
106 /// // Create the onion messenger. This must use the same `keys_manager` as is passed to your
107 /// // ChannelManager.
108 /// let onion_messenger = OnionMessenger::new(
109 /// &keys_manager, &keys_manager, logger, message_router, &offers_message_handler,
110 /// &custom_message_handler
113 /// # #[derive(Debug)]
114 /// # struct YourCustomMessage {}
115 /// impl Writeable for YourCustomMessage {
116 /// fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
118 /// // Write your custom onion message to `w`
121 /// impl OnionMessageContents for YourCustomMessage {
122 /// fn tlv_type(&self) -> u64 {
123 /// # let your_custom_message_type = 42;
124 /// your_custom_message_type
127 /// // Send a custom onion message to a node id.
128 /// let destination = Destination::Node(destination_node_id);
129 /// let reply_path = None;
130 /// # let message = YourCustomMessage {};
131 /// onion_messenger.send_onion_message(message, destination, reply_path);
133 /// // Create a blinded path to yourself, for someone to send an onion message to.
134 /// # let your_node_id = hop_node_id1;
135 /// let hops = [hop_node_id3, hop_node_id4, your_node_id];
136 /// let blinded_path = BlindedPath::new_for_message(&hops, &keys_manager, &secp_ctx).unwrap();
138 /// // Send a custom onion message to a blinded path.
139 /// let destination = Destination::BlindedPath(blinded_path);
140 /// let reply_path = None;
141 /// # let message = YourCustomMessage {};
142 /// onion_messenger.send_onion_message(message, destination, reply_path);
145 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
146 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
147 pub struct OnionMessenger<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref>
149 ES::Target: EntropySource,
150 NS::Target: NodeSigner,
152 MR::Target: MessageRouter,
153 OMH::Target: OffersMessageHandler,
154 CMH::Target: CustomOnionMessageHandler,
159 message_recipients: Mutex<HashMap<PublicKey, OnionMessageRecipient>>,
160 secp_ctx: Secp256k1<secp256k1::All>,
166 /// [`OnionMessage`]s buffered to be sent.
167 enum OnionMessageRecipient {
168 /// Messages for a node connected as a peer.
169 ConnectedPeer(VecDeque<OnionMessage>),
171 /// Messages for a node that is not yet connected, which are dropped after [`MAX_TIMER_TICKS`]
172 /// and tracked here.
173 PendingConnection(VecDeque<OnionMessage>, Option<Vec<SocketAddress>>, usize),
176 impl OnionMessageRecipient {
177 fn pending_connection(addresses: Vec<SocketAddress>) -> Self {
178 Self::PendingConnection(VecDeque::new(), Some(addresses), 0)
181 fn pending_messages(&self) -> &VecDeque<OnionMessage> {
183 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
184 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
188 fn enqueue_message(&mut self, message: OnionMessage) {
189 let pending_messages = match self {
190 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
191 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
194 pending_messages.push_back(message);
197 fn dequeue_message(&mut self) -> Option<OnionMessage> {
198 let pending_messages = match self {
199 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
200 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => {
201 debug_assert!(false);
206 pending_messages.pop_front()
210 fn release_pending_messages(&mut self) -> VecDeque<OnionMessage> {
211 let pending_messages = match self {
212 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
213 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
216 core::mem::take(pending_messages)
219 fn mark_connected(&mut self) {
220 if let OnionMessageRecipient::PendingConnection(pending_messages, _, _) = self {
221 let mut new_pending_messages = VecDeque::new();
222 core::mem::swap(pending_messages, &mut new_pending_messages);
223 *self = OnionMessageRecipient::ConnectedPeer(new_pending_messages);
227 fn is_connected(&self) -> bool {
229 OnionMessageRecipient::ConnectedPeer(..) => true,
230 OnionMessageRecipient::PendingConnection(..) => false,
235 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
237 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
238 /// enqueued for sending.
239 #[cfg(not(c_bindings))]
240 pub struct PendingOnionMessage<T: OnionMessageContents> {
241 /// The message contents to send in an [`OnionMessage`].
244 /// The destination of the message.
245 pub destination: Destination,
247 /// A reply path to include in the [`OnionMessage`] for a response.
248 pub reply_path: Option<BlindedPath>,
252 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
254 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
255 /// enqueued for sending.
256 pub type PendingOnionMessage<T: OnionMessageContents> = (T, Destination, Option<BlindedPath>);
258 pub(crate) fn new_pending_onion_message<T: OnionMessageContents>(
259 contents: T, destination: Destination, reply_path: Option<BlindedPath>
260 ) -> PendingOnionMessage<T> {
261 #[cfg(not(c_bindings))]
262 return PendingOnionMessage { contents, destination, reply_path };
264 return (contents, destination, reply_path);
267 /// A trait defining behavior for routing an [`OnionMessage`].
268 pub trait MessageRouter {
269 /// Returns a route for sending an [`OnionMessage`] to the given [`Destination`].
271 &self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
272 ) -> Result<OnionMessagePath, ()>;
275 /// A [`MessageRouter`] that can only route to a directly connected [`Destination`].
276 pub struct DefaultMessageRouter<G: Deref<Target=NetworkGraph<L>>, L: Deref>
283 impl<G: Deref<Target=NetworkGraph<L>>, L: Deref> DefaultMessageRouter<G, L>
287 /// Creates a [`DefaultMessageRouter`] using the given [`NetworkGraph`].
288 pub fn new(network_graph: G) -> Self {
289 Self { network_graph }
293 impl<G: Deref<Target=NetworkGraph<L>>, L: Deref> MessageRouter for DefaultMessageRouter<G, L>
298 &self, _sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
299 ) -> Result<OnionMessagePath, ()> {
300 let first_node = destination.first_node();
301 if peers.contains(&first_node) {
302 Ok(OnionMessagePath {
303 intermediate_nodes: vec![], destination, first_node_addresses: None
306 let network_graph = self.network_graph.deref().read_only();
307 let node_announcement = network_graph
308 .node(&NodeId::from_pubkey(&first_node))
309 .and_then(|node_info| node_info.announcement_info.as_ref())
310 .and_then(|announcement_info| announcement_info.announcement_message.as_ref())
311 .map(|node_announcement| &node_announcement.contents);
313 match node_announcement {
314 Some(node_announcement) if node_announcement.features.supports_onion_messages() => {
315 let first_node_addresses = Some(node_announcement.addresses.clone());
316 Ok(OnionMessagePath {
317 intermediate_nodes: vec![], destination, first_node_addresses
326 /// A path for sending an [`OnionMessage`].
328 pub struct OnionMessagePath {
329 /// Nodes on the path between the sender and the destination.
330 pub intermediate_nodes: Vec<PublicKey>,
332 /// The recipient of the message.
333 pub destination: Destination,
335 /// Addresses that may be used to connect to [`OnionMessagePath::first_node`].
337 /// Only needs to be set if a connection to the node is required. [`OnionMessenger`] may use
338 /// this to initiate such a connection.
339 pub first_node_addresses: Option<Vec<SocketAddress>>,
342 impl OnionMessagePath {
343 /// Returns the first node in the path.
344 pub fn first_node(&self) -> PublicKey {
345 self.intermediate_nodes
348 .unwrap_or_else(|| self.destination.first_node())
352 /// The destination of an onion message.
354 pub enum Destination {
355 /// We're sending this onion message to a node.
357 /// We're sending this onion message to a blinded path.
358 BlindedPath(BlindedPath),
362 pub(super) fn num_hops(&self) -> usize {
364 Destination::Node(_) => 1,
365 Destination::BlindedPath(BlindedPath { blinded_hops, .. }) => blinded_hops.len(),
369 fn first_node(&self) -> PublicKey {
371 Destination::Node(node_id) => *node_id,
372 Destination::BlindedPath(BlindedPath { introduction_node_id: node_id, .. }) => *node_id,
377 /// Result of successfully [sending an onion message].
379 /// [sending an onion message]: OnionMessenger::send_onion_message
380 #[derive(Debug, PartialEq, Eq)]
381 pub enum SendSuccess {
382 /// The message was buffered and will be sent once it is processed by
383 /// [`OnionMessageHandler::next_onion_message_for_peer`].
385 /// The message was buffered and will be sent once the node is connected as a peer and it is
386 /// processed by [`OnionMessageHandler::next_onion_message_for_peer`].
387 BufferedAwaitingConnection(PublicKey),
390 /// Errors that may occur when [sending an onion message].
392 /// [sending an onion message]: OnionMessenger::send_onion_message
393 #[derive(Debug, PartialEq, Eq)]
395 /// Errored computing onion message packet keys.
396 Secp256k1(secp256k1::Error),
397 /// Because implementations such as Eclair will drop onion messages where the message packet
398 /// exceeds 32834 bytes, we refuse to send messages where the packet exceeds this size.
400 /// The provided [`Destination`] was an invalid [`BlindedPath`] due to not having any blinded
403 /// The first hop is not a peer and doesn't have a known [`SocketAddress`].
404 InvalidFirstHop(PublicKey),
405 /// A path from the sender to the destination could not be found by the [`MessageRouter`].
407 /// Onion message contents must have a TLV type >= 64.
409 /// Our next-hop peer's buffer was full or our total outbound buffer was full.
411 /// Failed to retrieve our node id from the provided [`NodeSigner`].
413 /// [`NodeSigner`]: crate::sign::NodeSigner
415 /// We attempted to send to a blinded path where we are the introduction node, and failed to
416 /// advance the blinded path to make the second hop the new introduction node. Either
417 /// [`NodeSigner::ecdh`] failed, we failed to tweak the current blinding point to get the
418 /// new blinding point, or we were attempting to send to ourselves.
419 BlindedPathAdvanceFailed,
422 /// Handler for custom onion messages. If you are using [`SimpleArcOnionMessenger`],
423 /// [`SimpleRefOnionMessenger`], or prefer to ignore inbound custom onion messages,
424 /// [`IgnoringMessageHandler`] must be provided to [`OnionMessenger::new`]. Otherwise, a custom
425 /// implementation of this trait must be provided, with [`CustomMessage`] specifying the supported
428 /// See [`OnionMessenger`] for example usage.
430 /// [`IgnoringMessageHandler`]: crate::ln::peer_handler::IgnoringMessageHandler
431 /// [`CustomMessage`]: Self::CustomMessage
432 pub trait CustomOnionMessageHandler {
433 /// The message known to the handler. To support multiple message types, you may want to make this
434 /// an enum with a variant for each supported message.
435 type CustomMessage: OnionMessageContents;
437 /// Called with the custom message that was received, returning a response to send, if any.
439 /// The returned [`Self::CustomMessage`], if any, is enqueued to be sent by [`OnionMessenger`].
440 fn handle_custom_message(&self, msg: Self::CustomMessage) -> Option<Self::CustomMessage>;
442 /// Read a custom message of type `message_type` from `buffer`, returning `Ok(None)` if the
443 /// message type is unknown.
444 fn read_custom_message<R: io::Read>(&self, message_type: u64, buffer: &mut R) -> Result<Option<Self::CustomMessage>, msgs::DecodeError>;
446 /// Releases any [`Self::CustomMessage`]s that need to be sent.
448 /// Typically, this is used for messages initiating a message flow rather than in response to
449 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
450 #[cfg(not(c_bindings))]
451 fn release_pending_custom_messages(&self) -> Vec<PendingOnionMessage<Self::CustomMessage>>;
453 /// Releases any [`Self::CustomMessage`]s that need to be sent.
455 /// Typically, this is used for messages initiating a message flow rather than in response to
456 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
458 fn release_pending_custom_messages(&self) -> Vec<(Self::CustomMessage, Destination, Option<BlindedPath>)>;
461 /// A processed incoming onion message, containing either a Forward (another onion message)
462 /// or a Receive payload with decrypted contents.
463 pub enum PeeledOnion<T: OnionMessageContents> {
464 /// Forwarded onion, with the next node id and a new onion
465 Forward(PublicKey, OnionMessage),
466 /// Received onion message, with decrypted contents, path_id, and reply path
467 Receive(ParsedOnionMessageContents<T>, Option<[u8; 32]>, Option<BlindedPath>)
470 /// Creates an [`OnionMessage`] with the given `contents` for sending to the destination of
473 /// Returns the node id of the peer to send the message to, the message itself, and any addresses
474 /// need to connect to the first node.
475 pub fn create_onion_message<ES: Deref, NS: Deref, T: OnionMessageContents>(
476 entropy_source: &ES, node_signer: &NS, secp_ctx: &Secp256k1<secp256k1::All>,
477 path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
478 ) -> Result<(PublicKey, OnionMessage, Option<Vec<SocketAddress>>), SendError>
480 ES::Target: EntropySource,
481 NS::Target: NodeSigner,
483 let OnionMessagePath { intermediate_nodes, mut destination, first_node_addresses } = path;
484 if let Destination::BlindedPath(BlindedPath { ref blinded_hops, .. }) = destination {
485 if blinded_hops.is_empty() {
486 return Err(SendError::TooFewBlindedHops);
490 if contents.tlv_type() < 64 { return Err(SendError::InvalidMessage) }
492 // If we are sending straight to a blinded path and we are the introduction node, we need to
493 // advance the blinded path by 1 hop so the second hop is the new introduction node.
494 if intermediate_nodes.len() == 0 {
495 if let Destination::BlindedPath(ref mut blinded_path) = destination {
496 let our_node_id = node_signer.get_node_id(Recipient::Node)
497 .map_err(|()| SendError::GetNodeIdFailed)?;
498 if blinded_path.introduction_node_id == our_node_id {
499 advance_path_by_one(blinded_path, node_signer, &secp_ctx)
500 .map_err(|()| SendError::BlindedPathAdvanceFailed)?;
505 let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
506 let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
507 let (first_node_id, blinding_point) = if let Some(first_node_id) = intermediate_nodes.first() {
508 (*first_node_id, PublicKey::from_secret_key(&secp_ctx, &blinding_secret))
511 Destination::Node(pk) => (pk, PublicKey::from_secret_key(&secp_ctx, &blinding_secret)),
512 Destination::BlindedPath(BlindedPath { introduction_node_id, blinding_point, .. }) =>
513 (introduction_node_id, blinding_point),
516 let (packet_payloads, packet_keys) = packet_payloads_and_keys(
517 &secp_ctx, &intermediate_nodes, destination, contents, reply_path, &blinding_secret)
518 .map_err(|e| SendError::Secp256k1(e))?;
520 let prng_seed = entropy_source.get_secure_random_bytes();
521 let onion_routing_packet = construct_onion_message_packet(
522 packet_payloads, packet_keys, prng_seed).map_err(|()| SendError::TooBigPacket)?;
524 let message = OnionMessage { blinding_point, onion_routing_packet };
525 Ok((first_node_id, message, first_node_addresses))
528 /// Decode one layer of an incoming [`OnionMessage`].
530 /// Returns either the next layer of the onion for forwarding or the decrypted content for the
532 pub fn peel_onion_message<NS: Deref, L: Deref, CMH: Deref>(
533 msg: &OnionMessage, secp_ctx: &Secp256k1<secp256k1::All>, node_signer: NS, logger: L,
535 ) -> Result<PeeledOnion<<<CMH>::Target as CustomOnionMessageHandler>::CustomMessage>, ()>
537 NS::Target: NodeSigner,
539 CMH::Target: CustomOnionMessageHandler,
541 let control_tlvs_ss = match node_signer.ecdh(Recipient::Node, &msg.blinding_point, None) {
544 log_error!(logger, "Failed to retrieve node secret: {:?}", e);
548 let onion_decode_ss = {
549 let blinding_factor = {
550 let mut hmac = HmacEngine::<Sha256>::new(b"blinded_node_id");
551 hmac.input(control_tlvs_ss.as_ref());
552 Hmac::from_engine(hmac).to_byte_array()
554 match node_signer.ecdh(Recipient::Node, &msg.onion_routing_packet.public_key,
555 Some(&Scalar::from_be_bytes(blinding_factor).unwrap()))
557 Ok(ss) => ss.secret_bytes(),
559 log_trace!(logger, "Failed to compute onion packet shared secret");
564 match onion_utils::decode_next_untagged_hop(
565 onion_decode_ss, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
566 (control_tlvs_ss, custom_handler.deref(), logger.deref())
568 Ok((Payload::Receive::<ParsedOnionMessageContents<<<CMH as Deref>::Target as CustomOnionMessageHandler>::CustomMessage>> {
569 message, control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id }), reply_path,
571 Ok(PeeledOnion::Receive(message, path_id, reply_path))
573 Ok((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
574 next_node_id, next_blinding_override
575 })), Some((next_hop_hmac, new_packet_bytes)))) => {
576 // TODO: we need to check whether `next_node_id` is our node, in which case this is a dummy
577 // blinded hop and this onion message is destined for us. In this situation, we should keep
578 // unwrapping the onion layers to get to the final payload. Since we don't have the option
579 // of creating blinded paths with dummy hops currently, we should be ok to not handle this
581 let new_pubkey = match onion_utils::next_hop_pubkey(&secp_ctx, msg.onion_routing_packet.public_key, &onion_decode_ss) {
584 log_trace!(logger, "Failed to compute next hop packet pubkey: {}", e);
588 let outgoing_packet = Packet {
590 public_key: new_pubkey,
591 hop_data: new_packet_bytes,
594 let onion_message = OnionMessage {
595 blinding_point: match next_blinding_override {
596 Some(blinding_point) => blinding_point,
598 match onion_utils::next_hop_pubkey(
599 &secp_ctx, msg.blinding_point, control_tlvs_ss.as_ref()
603 log_trace!(logger, "Failed to compute next blinding point: {}", e);
609 onion_routing_packet: outgoing_packet,
612 Ok(PeeledOnion::Forward(next_node_id, onion_message))
615 log_trace!(logger, "Errored decoding onion message packet: {:?}", e);
619 log_trace!(logger, "Received bogus onion message packet, either the sender encoded a final hop as a forwarding hop or vice versa");
625 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref>
626 OnionMessenger<ES, NS, L, MR, OMH, CMH>
628 ES::Target: EntropySource,
629 NS::Target: NodeSigner,
631 MR::Target: MessageRouter,
632 OMH::Target: OffersMessageHandler,
633 CMH::Target: CustomOnionMessageHandler,
635 /// Constructs a new `OnionMessenger` to send, forward, and delegate received onion messages to
636 /// their respective handlers.
638 entropy_source: ES, node_signer: NS, logger: L, message_router: MR, offers_handler: OMH,
641 let mut secp_ctx = Secp256k1::new();
642 secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
646 message_recipients: Mutex::new(HashMap::new()),
655 /// Sends an [`OnionMessage`] with the given `contents` to `destination`.
657 /// See [`OnionMessenger`] for example usage.
658 pub fn send_onion_message<T: OnionMessageContents>(
659 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>
660 ) -> Result<SendSuccess, SendError> {
661 self.find_path_and_enqueue_onion_message(
662 contents, destination, reply_path, format_args!("")
666 fn find_path_and_enqueue_onion_message<T: OnionMessageContents>(
667 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>,
668 log_suffix: fmt::Arguments
669 ) -> Result<SendSuccess, SendError> {
670 let result = self.find_path(destination)
671 .and_then(|path| self.enqueue_onion_message(path, contents, reply_path, log_suffix));
673 match result.as_ref() {
674 Err(SendError::GetNodeIdFailed) => {
675 log_warn!(self.logger, "Unable to retrieve node id {}", log_suffix);
677 Err(SendError::PathNotFound) => {
678 log_trace!(self.logger, "Failed to find path {}", log_suffix);
681 log_trace!(self.logger, "Failed sending onion message {}: {:?}", log_suffix, e);
683 Ok(SendSuccess::Buffered) => {
684 log_trace!(self.logger, "Buffered onion message {}", log_suffix);
686 Ok(SendSuccess::BufferedAwaitingConnection(node_id)) => {
688 self.logger, "Buffered onion message waiting on peer connection {}: {:?}",
697 fn find_path(&self, destination: Destination) -> Result<OnionMessagePath, SendError> {
698 let sender = self.node_signer
699 .get_node_id(Recipient::Node)
700 .map_err(|_| SendError::GetNodeIdFailed)?;
702 let peers = self.message_recipients.lock().unwrap()
704 .filter(|(_, recipient)| matches!(recipient, OnionMessageRecipient::ConnectedPeer(_)))
705 .map(|(node_id, _)| *node_id)
709 .find_path(sender, peers, destination)
710 .map_err(|_| SendError::PathNotFound)
713 fn enqueue_onion_message<T: OnionMessageContents>(
714 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
715 log_suffix: fmt::Arguments
716 ) -> Result<SendSuccess, SendError> {
717 log_trace!(self.logger, "Constructing onion message {}: {:?}", log_suffix, contents);
719 let (first_node_id, onion_message, addresses) = create_onion_message(
720 &self.entropy_source, &self.node_signer, &self.secp_ctx, path, contents, reply_path
723 let mut message_recipients = self.message_recipients.lock().unwrap();
724 if outbound_buffer_full(&first_node_id, &message_recipients) {
725 return Err(SendError::BufferFull);
728 match message_recipients.entry(first_node_id) {
729 hash_map::Entry::Vacant(e) => match addresses {
730 None => Err(SendError::InvalidFirstHop(first_node_id)),
732 e.insert(OnionMessageRecipient::pending_connection(addresses))
733 .enqueue_message(onion_message);
734 Ok(SendSuccess::BufferedAwaitingConnection(first_node_id))
737 hash_map::Entry::Occupied(mut e) => {
738 e.get_mut().enqueue_message(onion_message);
739 if e.get().is_connected() {
740 Ok(SendSuccess::Buffered)
742 Ok(SendSuccess::BufferedAwaitingConnection(first_node_id))
749 pub(super) fn send_onion_message_using_path<T: OnionMessageContents>(
750 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>
751 ) -> Result<SendSuccess, SendError> {
752 self.enqueue_onion_message(path, contents, reply_path, format_args!(""))
755 fn handle_onion_message_response<T: OnionMessageContents>(
756 &self, response: Option<T>, reply_path: Option<BlindedPath>, log_suffix: fmt::Arguments
758 if let Some(response) = response {
760 Some(reply_path) => {
761 let _ = self.find_path_and_enqueue_onion_message(
762 response, Destination::BlindedPath(reply_path), None, log_suffix
766 log_trace!(self.logger, "Missing reply path {}", log_suffix);
773 pub(super) fn release_pending_msgs(&self) -> HashMap<PublicKey, VecDeque<OnionMessage>> {
774 let mut message_recipients = self.message_recipients.lock().unwrap();
775 let mut msgs = HashMap::new();
776 // We don't want to disconnect the peers by removing them entirely from the original map, so we
777 // release the pending message buffers individually.
778 for (node_id, recipient) in &mut *message_recipients {
779 msgs.insert(*node_id, recipient.release_pending_messages());
785 fn outbound_buffer_full(peer_node_id: &PublicKey, buffer: &HashMap<PublicKey, OnionMessageRecipient>) -> bool {
786 const MAX_TOTAL_BUFFER_SIZE: usize = (1 << 20) * 128;
787 const MAX_PER_PEER_BUFFER_SIZE: usize = (1 << 10) * 256;
788 let mut total_buffered_bytes = 0;
789 let mut peer_buffered_bytes = 0;
790 for (pk, peer_buf) in buffer {
791 for om in peer_buf.pending_messages() {
792 let om_len = om.serialized_length();
793 if pk == peer_node_id {
794 peer_buffered_bytes += om_len;
796 total_buffered_bytes += om_len;
798 if total_buffered_bytes >= MAX_TOTAL_BUFFER_SIZE ||
799 peer_buffered_bytes >= MAX_PER_PEER_BUFFER_SIZE
808 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref> EventsProvider
809 for OnionMessenger<ES, NS, L, MR, OMH, CMH>
811 ES::Target: EntropySource,
812 NS::Target: NodeSigner,
814 MR::Target: MessageRouter,
815 OMH::Target: OffersMessageHandler,
816 CMH::Target: CustomOnionMessageHandler,
818 fn process_pending_events<H: Deref>(&self, handler: H) where H::Target: EventHandler {
819 for (node_id, recipient) in self.message_recipients.lock().unwrap().iter_mut() {
820 if let OnionMessageRecipient::PendingConnection(_, addresses, _) = recipient {
821 if let Some(addresses) = addresses.take() {
822 handler.handle_event(Event::ConnectionNeeded { node_id: *node_id, addresses });
829 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref> OnionMessageHandler
830 for OnionMessenger<ES, NS, L, MR, OMH, CMH>
832 ES::Target: EntropySource,
833 NS::Target: NodeSigner,
835 MR::Target: MessageRouter,
836 OMH::Target: OffersMessageHandler,
837 CMH::Target: CustomOnionMessageHandler,
839 fn handle_onion_message(&self, _peer_node_id: &PublicKey, msg: &OnionMessage) {
840 match peel_onion_message(
841 msg, &self.secp_ctx, &*self.node_signer, &*self.logger, &*self.custom_handler
843 Ok(PeeledOnion::Receive(message, path_id, reply_path)) => {
846 "Received an onion message with path_id {:02x?} and {} reply_path: {:?}",
847 path_id, if reply_path.is_some() { "a" } else { "no" }, message);
850 ParsedOnionMessageContents::Offers(msg) => {
851 let response = self.offers_handler.handle_message(msg);
852 self.handle_onion_message_response(
853 response, reply_path, format_args!(
854 "when responding to Offers onion message with path_id {:02x?}",
859 ParsedOnionMessageContents::Custom(msg) => {
860 let response = self.custom_handler.handle_custom_message(msg);
861 self.handle_onion_message_response(
862 response, reply_path, format_args!(
863 "when responding to Custom onion message with path_id {:02x?}",
870 Ok(PeeledOnion::Forward(next_node_id, onion_message)) => {
871 let mut message_recipients = self.message_recipients.lock().unwrap();
872 if outbound_buffer_full(&next_node_id, &message_recipients) {
873 log_trace!(self.logger, "Dropping forwarded onion message to peer {:?}: outbound buffer full", next_node_id);
880 .or_insert_with(|| OnionMessageRecipient::ConnectedPeer(VecDeque::new()));
882 match message_recipients.entry(next_node_id) {
883 hash_map::Entry::Occupied(mut e) if matches!(
884 e.get(), OnionMessageRecipient::ConnectedPeer(..)
886 e.get_mut().enqueue_message(onion_message);
887 log_trace!(self.logger, "Forwarding an onion message to peer {}", next_node_id);
890 log_trace!(self.logger, "Dropping forwarded onion message to disconnected peer {:?}", next_node_id);
896 log_error!(self.logger, "Failed to process onion message {:?}", e);
901 fn peer_connected(&self, their_node_id: &PublicKey, init: &msgs::Init, _inbound: bool) -> Result<(), ()> {
902 if init.features.supports_onion_messages() {
903 self.message_recipients.lock().unwrap()
904 .entry(*their_node_id)
905 .or_insert_with(|| OnionMessageRecipient::ConnectedPeer(VecDeque::new()))
908 self.message_recipients.lock().unwrap().remove(their_node_id);
914 fn peer_disconnected(&self, their_node_id: &PublicKey) {
915 match self.message_recipients.lock().unwrap().remove(their_node_id) {
916 Some(OnionMessageRecipient::ConnectedPeer(..)) => {},
917 _ => debug_assert!(false),
921 fn timer_tick_occurred(&self) {
922 let mut message_recipients = self.message_recipients.lock().unwrap();
924 // Drop any pending recipients since the last call to avoid retaining buffered messages for
926 message_recipients.retain(|_, recipient| match recipient {
927 OnionMessageRecipient::PendingConnection(_, None, ticks) => *ticks < MAX_TIMER_TICKS,
928 OnionMessageRecipient::PendingConnection(_, Some(_), _) => true,
932 // Increment a timer tick for pending recipients so that their buffered messages are dropped
933 // at MAX_TIMER_TICKS.
934 for recipient in message_recipients.values_mut() {
935 if let OnionMessageRecipient::PendingConnection(_, None, ticks) = recipient {
941 fn provided_node_features(&self) -> NodeFeatures {
942 let mut features = NodeFeatures::empty();
943 features.set_onion_messages_optional();
947 fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
948 let mut features = InitFeatures::empty();
949 features.set_onion_messages_optional();
953 // Before returning any messages to send for the peer, this method will see if any messages were
954 // enqueued in the handler by users, find a path to the corresponding blinded path's introduction
955 // node, and then enqueue the message for sending to the first peer in the full path.
956 fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<OnionMessage> {
957 // Enqueue any initiating `OffersMessage`s to send.
958 for message in self.offers_handler.release_pending_messages() {
959 #[cfg(not(c_bindings))]
960 let PendingOnionMessage { contents, destination, reply_path } = message;
962 let (contents, destination, reply_path) = message;
963 let _ = self.find_path_and_enqueue_onion_message(
964 contents, destination, reply_path, format_args!("when sending OffersMessage")
968 // Enqueue any initiating `CustomMessage`s to send.
969 for message in self.custom_handler.release_pending_custom_messages() {
970 #[cfg(not(c_bindings))]
971 let PendingOnionMessage { contents, destination, reply_path } = message;
973 let (contents, destination, reply_path) = message;
974 let _ = self.find_path_and_enqueue_onion_message(
975 contents, destination, reply_path, format_args!("when sending CustomMessage")
979 self.message_recipients.lock().unwrap()
980 .get_mut(&peer_node_id)
981 .and_then(|buffer| buffer.dequeue_message())
985 // TODO: parameterize the below Simple* types with OnionMessenger and handle the messages it
987 /// Useful for simplifying the parameters of [`SimpleArcChannelManager`] and
988 /// [`SimpleArcPeerManager`]. See their docs for more details.
990 /// This is not exported to bindings users as type aliases aren't supported in most languages.
992 /// [`SimpleArcChannelManager`]: crate::ln::channelmanager::SimpleArcChannelManager
993 /// [`SimpleArcPeerManager`]: crate::ln::peer_handler::SimpleArcPeerManager
994 #[cfg(not(c_bindings))]
995 pub type SimpleArcOnionMessenger<M, T, F, L> = OnionMessenger<
999 Arc<DefaultMessageRouter<Arc<NetworkGraph<Arc<L>>>, Arc<L>>>,
1000 Arc<SimpleArcChannelManager<M, T, F, L>>,
1001 IgnoringMessageHandler
1004 /// Useful for simplifying the parameters of [`SimpleRefChannelManager`] and
1005 /// [`SimpleRefPeerManager`]. See their docs for more details.
1007 /// This is not exported to bindings users as type aliases aren't supported in most languages.
1009 /// [`SimpleRefChannelManager`]: crate::ln::channelmanager::SimpleRefChannelManager
1010 /// [`SimpleRefPeerManager`]: crate::ln::peer_handler::SimpleRefPeerManager
1011 #[cfg(not(c_bindings))]
1012 pub type SimpleRefOnionMessenger<
1013 'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, 'i, 'j, M, T, F, L
1018 &'i DefaultMessageRouter<&'g NetworkGraph<&'b L>, &'b L>,
1019 &'j SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, M, T, F, L>,
1020 IgnoringMessageHandler
1023 /// Construct onion packet payloads and keys for sending an onion message along the given
1024 /// `unblinded_path` to the given `destination`.
1025 fn packet_payloads_and_keys<T: OnionMessageContents, S: secp256k1::Signing + secp256k1::Verification>(
1026 secp_ctx: &Secp256k1<S>, unblinded_path: &[PublicKey], destination: Destination, message: T,
1027 mut reply_path: Option<BlindedPath>, session_priv: &SecretKey
1028 ) -> Result<(Vec<(Payload<T>, [u8; 32])>, Vec<onion_utils::OnionKeys>), secp256k1::Error> {
1029 let num_hops = unblinded_path.len() + destination.num_hops();
1030 let mut payloads = Vec::with_capacity(num_hops);
1031 let mut onion_packet_keys = Vec::with_capacity(num_hops);
1033 let (mut intro_node_id_blinding_pt, num_blinded_hops) = if let Destination::BlindedPath(BlindedPath {
1034 introduction_node_id, blinding_point, blinded_hops }) = &destination {
1035 (Some((*introduction_node_id, *blinding_point)), blinded_hops.len()) } else { (None, 0) };
1036 let num_unblinded_hops = num_hops - num_blinded_hops;
1038 let mut unblinded_path_idx = 0;
1039 let mut blinded_path_idx = 0;
1040 let mut prev_control_tlvs_ss = None;
1041 let mut final_control_tlvs = None;
1042 utils::construct_keys_callback(secp_ctx, unblinded_path.iter(), Some(destination), session_priv,
1043 |_, onion_packet_ss, ephemeral_pubkey, control_tlvs_ss, unblinded_pk_opt, enc_payload_opt| {
1044 if num_unblinded_hops != 0 && unblinded_path_idx < num_unblinded_hops {
1045 if let Some(ss) = prev_control_tlvs_ss.take() {
1046 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(
1048 next_node_id: unblinded_pk_opt.unwrap(),
1049 next_blinding_override: None,
1053 prev_control_tlvs_ss = Some(control_tlvs_ss);
1054 unblinded_path_idx += 1;
1055 } else if let Some((intro_node_id, blinding_pt)) = intro_node_id_blinding_pt.take() {
1056 if let Some(control_tlvs_ss) = prev_control_tlvs_ss.take() {
1057 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
1058 next_node_id: intro_node_id,
1059 next_blinding_override: Some(blinding_pt),
1060 })), control_tlvs_ss));
1063 if blinded_path_idx < num_blinded_hops.saturating_sub(1) && enc_payload_opt.is_some() {
1064 payloads.push((Payload::Forward(ForwardControlTlvs::Blinded(enc_payload_opt.unwrap())),
1066 blinded_path_idx += 1;
1067 } else if let Some(encrypted_payload) = enc_payload_opt {
1068 final_control_tlvs = Some(ReceiveControlTlvs::Blinded(encrypted_payload));
1069 prev_control_tlvs_ss = Some(control_tlvs_ss);
1072 let (rho, mu) = onion_utils::gen_rho_mu_from_shared_secret(onion_packet_ss.as_ref());
1073 onion_packet_keys.push(onion_utils::OnionKeys {
1075 shared_secret: onion_packet_ss,
1077 blinding_factor: [0; 32],
1085 if let Some(control_tlvs) = final_control_tlvs {
1086 payloads.push((Payload::Receive {
1088 reply_path: reply_path.take(),
1090 }, prev_control_tlvs_ss.unwrap()));
1092 payloads.push((Payload::Receive {
1093 control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id: None, }),
1094 reply_path: reply_path.take(),
1096 }, prev_control_tlvs_ss.unwrap()));
1099 Ok((payloads, onion_packet_keys))
1102 /// Errors if the serialized payload size exceeds onion_message::BIG_PACKET_HOP_DATA_LEN
1103 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, ()> {
1105 // "`len` allows larger messages to be sent than the standard 1300 bytes allowed for an HTLC
1106 // onion, but this should be used sparingly as it is reduces anonymity set, hence the
1107 // recommendation that it either look like an HTLC onion, or if larger, be a fixed size."
1108 let payloads_ser_len = onion_utils::payloads_serialized_length(&payloads);
1109 let hop_data_len = if payloads_ser_len <= SMALL_PACKET_HOP_DATA_LEN {
1110 SMALL_PACKET_HOP_DATA_LEN
1111 } else if payloads_ser_len <= BIG_PACKET_HOP_DATA_LEN {
1112 BIG_PACKET_HOP_DATA_LEN
1113 } else { return Err(()) };
1115 onion_utils::construct_onion_message_packet::<_, _>(
1116 payloads, onion_keys, prng_seed, hop_data_len)