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 this [`OnionMessenger`], which lives here,
11 //! as well as various types, traits, and utilities that it uses.
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, 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::routing::gossip::{NetworkGraph, NodeId};
29 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::Mutex;
40 use crate::prelude::*;
42 #[cfg(not(c_bindings))]
44 crate::sign::KeysManager,
45 crate::ln::peer_handler::IgnoringMessageHandler,
49 pub(super) const MAX_TIMER_TICKS: usize = 2;
51 /// A sender, receiver and forwarder of [`OnionMessage`]s.
53 /// # Handling Messages
55 /// `OnionMessenger` implements [`OnionMessageHandler`], making it responsible for either forwarding
56 /// messages to peers or delegating to the appropriate handler for the message type. Currently, the
57 /// available handlers are:
58 /// * [`OffersMessageHandler`], for responding to [`InvoiceRequest`]s and paying [`Bolt12Invoice`]s
59 /// * [`CustomOnionMessageHandler`], for handling user-defined message types
61 /// # Sending Messages
63 /// [`OnionMessage`]s are sent initially using [`OnionMessenger::send_onion_message`]. When handling
64 /// a message, the matched handler may return a response message which `OnionMessenger` will send
70 /// # extern crate bitcoin;
71 /// # use bitcoin::hashes::_export::_core::time::Duration;
72 /// # use bitcoin::hashes::hex::FromHex;
73 /// # use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey, self};
74 /// # use lightning::blinded_path::BlindedPath;
75 /// # use lightning::sign::{EntropySource, KeysManager};
76 /// # use lightning::ln::peer_handler::IgnoringMessageHandler;
77 /// # use lightning::onion_message::messenger::{Destination, MessageRouter, OnionMessagePath, OnionMessenger};
78 /// # use lightning::onion_message::packet::OnionMessageContents;
79 /// # use lightning::util::logger::{Logger, Record};
80 /// # use lightning::util::ser::{Writeable, Writer};
81 /// # use lightning::io;
82 /// # use std::sync::Arc;
83 /// # struct FakeLogger;
84 /// # impl Logger for FakeLogger {
85 /// # fn log(&self, record: Record) { println!("{:?}" , record); }
87 /// # struct FakeMessageRouter {}
88 /// # impl MessageRouter for FakeMessageRouter {
89 /// # fn find_path(&self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination) -> Result<OnionMessagePath, ()> {
90 /// # let secp_ctx = Secp256k1::new();
91 /// # let node_secret = SecretKey::from_slice(&<Vec<u8>>::from_hex("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
92 /// # let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
93 /// # let hop_node_id2 = hop_node_id1;
94 /// # Ok(OnionMessagePath {
95 /// # intermediate_nodes: vec![hop_node_id1, hop_node_id2],
97 /// # first_node_addresses: None,
100 /// # fn create_blinded_paths<ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
101 /// # &self, _recipient: PublicKey, _peers: Vec<PublicKey>, _entropy_source: &ES, _secp_ctx: &Secp256k1<T>
102 /// # ) -> Result<Vec<BlindedPath>, ()> {
106 /// # let seed = [42u8; 32];
107 /// # let time = Duration::from_secs(123456);
108 /// # let keys_manager = KeysManager::new(&seed, time.as_secs(), time.subsec_nanos());
109 /// # let logger = Arc::new(FakeLogger {});
110 /// # let node_secret = SecretKey::from_slice(&<Vec<u8>>::from_hex("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
111 /// # let secp_ctx = Secp256k1::new();
112 /// # let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
113 /// # let (hop_node_id3, hop_node_id4) = (hop_node_id1, hop_node_id1);
114 /// # let destination_node_id = hop_node_id1;
115 /// # let message_router = Arc::new(FakeMessageRouter {});
116 /// # let custom_message_handler = IgnoringMessageHandler {};
117 /// # let offers_message_handler = IgnoringMessageHandler {};
118 /// // Create the onion messenger. This must use the same `keys_manager` as is passed to your
119 /// // ChannelManager.
120 /// let onion_messenger = OnionMessenger::new(
121 /// &keys_manager, &keys_manager, logger, message_router, &offers_message_handler,
122 /// &custom_message_handler
125 /// # #[derive(Debug)]
126 /// # struct YourCustomMessage {}
127 /// impl Writeable for YourCustomMessage {
128 /// fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
130 /// // Write your custom onion message to `w`
133 /// impl OnionMessageContents for YourCustomMessage {
134 /// fn tlv_type(&self) -> u64 {
135 /// # let your_custom_message_type = 42;
136 /// your_custom_message_type
139 /// // Send a custom onion message to a node id.
140 /// let destination = Destination::Node(destination_node_id);
141 /// let reply_path = None;
142 /// # let message = YourCustomMessage {};
143 /// onion_messenger.send_onion_message(message, destination, reply_path);
145 /// // Create a blinded path to yourself, for someone to send an onion message to.
146 /// # let your_node_id = hop_node_id1;
147 /// let hops = [hop_node_id3, hop_node_id4, your_node_id];
148 /// let blinded_path = BlindedPath::new_for_message(&hops, &keys_manager, &secp_ctx).unwrap();
150 /// // Send a custom onion message to a blinded path.
151 /// let destination = Destination::BlindedPath(blinded_path);
152 /// let reply_path = None;
153 /// # let message = YourCustomMessage {};
154 /// onion_messenger.send_onion_message(message, destination, reply_path);
157 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
158 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
159 pub struct OnionMessenger<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref>
161 ES::Target: EntropySource,
162 NS::Target: NodeSigner,
164 MR::Target: MessageRouter,
165 OMH::Target: OffersMessageHandler,
166 CMH::Target: CustomOnionMessageHandler,
171 message_recipients: Mutex<HashMap<PublicKey, OnionMessageRecipient>>,
172 secp_ctx: Secp256k1<secp256k1::All>,
178 /// [`OnionMessage`]s buffered to be sent.
179 enum OnionMessageRecipient {
180 /// Messages for a node connected as a peer.
181 ConnectedPeer(VecDeque<OnionMessage>),
183 /// Messages for a node that is not yet connected, which are dropped after [`MAX_TIMER_TICKS`]
184 /// and tracked here.
185 PendingConnection(VecDeque<OnionMessage>, Option<Vec<SocketAddress>>, usize),
188 impl OnionMessageRecipient {
189 fn pending_connection(addresses: Vec<SocketAddress>) -> Self {
190 Self::PendingConnection(VecDeque::new(), Some(addresses), 0)
193 fn pending_messages(&self) -> &VecDeque<OnionMessage> {
195 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
196 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
200 fn enqueue_message(&mut self, message: OnionMessage) {
201 let pending_messages = match self {
202 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
203 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
206 pending_messages.push_back(message);
209 fn dequeue_message(&mut self) -> Option<OnionMessage> {
210 let pending_messages = match self {
211 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
212 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => {
213 debug_assert!(false);
218 pending_messages.pop_front()
222 fn release_pending_messages(&mut self) -> VecDeque<OnionMessage> {
223 let pending_messages = match self {
224 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
225 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
228 core::mem::take(pending_messages)
231 fn mark_connected(&mut self) {
232 if let OnionMessageRecipient::PendingConnection(pending_messages, _, _) = self {
233 let mut new_pending_messages = VecDeque::new();
234 core::mem::swap(pending_messages, &mut new_pending_messages);
235 *self = OnionMessageRecipient::ConnectedPeer(new_pending_messages);
239 fn is_connected(&self) -> bool {
241 OnionMessageRecipient::ConnectedPeer(..) => true,
242 OnionMessageRecipient::PendingConnection(..) => false,
247 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
249 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
250 /// enqueued for sending.
251 #[cfg(not(c_bindings))]
252 pub struct PendingOnionMessage<T: OnionMessageContents> {
253 /// The message contents to send in an [`OnionMessage`].
256 /// The destination of the message.
257 pub destination: Destination,
259 /// A reply path to include in the [`OnionMessage`] for a response.
260 pub reply_path: Option<BlindedPath>,
264 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
266 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
267 /// enqueued for sending.
268 pub type PendingOnionMessage<T> = (T, Destination, Option<BlindedPath>);
270 pub(crate) fn new_pending_onion_message<T: OnionMessageContents>(
271 contents: T, destination: Destination, reply_path: Option<BlindedPath>
272 ) -> PendingOnionMessage<T> {
273 #[cfg(not(c_bindings))]
274 return PendingOnionMessage { contents, destination, reply_path };
276 return (contents, destination, reply_path);
279 /// A trait defining behavior for routing an [`OnionMessage`].
280 pub trait MessageRouter {
281 /// Returns a route for sending an [`OnionMessage`] to the given [`Destination`].
283 &self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
284 ) -> Result<OnionMessagePath, ()>;
286 /// Creates [`BlindedPath`]s to the `recipient` node. The nodes in `peers` are assumed to be
287 /// direct peers with the `recipient`.
288 fn create_blinded_paths<
289 ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification
291 &self, recipient: PublicKey, peers: Vec<PublicKey>, entropy_source: &ES,
292 secp_ctx: &Secp256k1<T>
293 ) -> Result<Vec<BlindedPath>, ()>;
296 /// A [`MessageRouter`] that can only route to a directly connected [`Destination`].
297 pub struct DefaultMessageRouter<G: Deref<Target=NetworkGraph<L>>, L: Deref>
304 impl<G: Deref<Target=NetworkGraph<L>>, L: Deref> DefaultMessageRouter<G, L>
308 /// Creates a [`DefaultMessageRouter`] using the given [`NetworkGraph`].
309 pub fn new(network_graph: G) -> Self {
310 Self { network_graph }
314 impl<G: Deref<Target=NetworkGraph<L>>, L: Deref> MessageRouter for DefaultMessageRouter<G, L>
319 &self, _sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
320 ) -> Result<OnionMessagePath, ()> {
321 let first_node = destination.first_node();
322 if peers.contains(&first_node) {
323 Ok(OnionMessagePath {
324 intermediate_nodes: vec![], destination, first_node_addresses: None
327 let network_graph = self.network_graph.deref().read_only();
328 let node_announcement = network_graph
329 .node(&NodeId::from_pubkey(&first_node))
330 .and_then(|node_info| node_info.announcement_info.as_ref())
331 .and_then(|announcement_info| announcement_info.announcement_message.as_ref())
332 .map(|node_announcement| &node_announcement.contents);
334 match node_announcement {
335 Some(node_announcement) if node_announcement.features.supports_onion_messages() => {
336 let first_node_addresses = Some(node_announcement.addresses.clone());
337 Ok(OnionMessagePath {
338 intermediate_nodes: vec![], destination, first_node_addresses
346 fn create_blinded_paths<
347 ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification
349 &self, recipient: PublicKey, peers: Vec<PublicKey>, entropy_source: &ES,
350 secp_ctx: &Secp256k1<T>
351 ) -> Result<Vec<BlindedPath>, ()> {
352 // Limit the number of blinded paths that are computed.
353 const MAX_PATHS: usize = 3;
355 // Ensure peers have at least three channels so that it is more difficult to infer the
356 // recipient's node_id.
357 const MIN_PEER_CHANNELS: usize = 3;
359 let network_graph = self.network_graph.deref().read_only();
360 let paths = peers.iter()
361 // Limit to peers with announced channels
364 .node(&NodeId::from_pubkey(pubkey))
365 .map(|info| &info.channels[..])
366 .map(|channels| channels.len() >= MIN_PEER_CHANNELS)
369 .map(|pubkey| vec![*pubkey, recipient])
370 .map(|node_pks| BlindedPath::new_for_message(&node_pks, entropy_source, secp_ctx))
372 .collect::<Result<Vec<_>, _>>();
375 Ok(paths) if !paths.is_empty() => Ok(paths),
377 if network_graph.nodes().contains_key(&NodeId::from_pubkey(&recipient)) {
378 BlindedPath::one_hop_for_message(recipient, entropy_source, secp_ctx)
379 .map(|path| vec![path])
388 /// A path for sending an [`OnionMessage`].
390 pub struct OnionMessagePath {
391 /// Nodes on the path between the sender and the destination.
392 pub intermediate_nodes: Vec<PublicKey>,
394 /// The recipient of the message.
395 pub destination: Destination,
397 /// Addresses that may be used to connect to [`OnionMessagePath::first_node`].
399 /// Only needs to be set if a connection to the node is required. [`OnionMessenger`] may use
400 /// this to initiate such a connection.
401 pub first_node_addresses: Option<Vec<SocketAddress>>,
404 impl OnionMessagePath {
405 /// Returns the first node in the path.
406 pub fn first_node(&self) -> PublicKey {
407 self.intermediate_nodes
410 .unwrap_or_else(|| self.destination.first_node())
414 /// The destination of an onion message.
416 pub enum Destination {
417 /// We're sending this onion message to a node.
419 /// We're sending this onion message to a blinded path.
420 BlindedPath(BlindedPath),
424 pub(super) fn num_hops(&self) -> usize {
426 Destination::Node(_) => 1,
427 Destination::BlindedPath(BlindedPath { blinded_hops, .. }) => blinded_hops.len(),
431 fn first_node(&self) -> PublicKey {
433 Destination::Node(node_id) => *node_id,
434 Destination::BlindedPath(BlindedPath { introduction_node_id: node_id, .. }) => *node_id,
439 /// Result of successfully [sending an onion message].
441 /// [sending an onion message]: OnionMessenger::send_onion_message
442 #[derive(Debug, PartialEq, Eq)]
443 pub enum SendSuccess {
444 /// The message was buffered and will be sent once it is processed by
445 /// [`OnionMessageHandler::next_onion_message_for_peer`].
447 /// The message was buffered and will be sent once the node is connected as a peer and it is
448 /// processed by [`OnionMessageHandler::next_onion_message_for_peer`].
449 BufferedAwaitingConnection(PublicKey),
452 /// Errors that may occur when [sending an onion message].
454 /// [sending an onion message]: OnionMessenger::send_onion_message
455 #[derive(Debug, PartialEq, Eq)]
457 /// Errored computing onion message packet keys.
458 Secp256k1(secp256k1::Error),
459 /// Because implementations such as Eclair will drop onion messages where the message packet
460 /// exceeds 32834 bytes, we refuse to send messages where the packet exceeds this size.
462 /// The provided [`Destination`] was an invalid [`BlindedPath`] due to not having any blinded
465 /// The first hop is not a peer and doesn't have a known [`SocketAddress`].
466 InvalidFirstHop(PublicKey),
467 /// A path from the sender to the destination could not be found by the [`MessageRouter`].
469 /// Onion message contents must have a TLV type >= 64.
471 /// Our next-hop peer's buffer was full or our total outbound buffer was full.
473 /// Failed to retrieve our node id from the provided [`NodeSigner`].
475 /// [`NodeSigner`]: crate::sign::NodeSigner
477 /// We attempted to send to a blinded path where we are the introduction node, and failed to
478 /// advance the blinded path to make the second hop the new introduction node. Either
479 /// [`NodeSigner::ecdh`] failed, we failed to tweak the current blinding point to get the
480 /// new blinding point, or we were attempting to send to ourselves.
481 BlindedPathAdvanceFailed,
484 /// Handler for custom onion messages. If you are using [`SimpleArcOnionMessenger`],
485 /// [`SimpleRefOnionMessenger`], or prefer to ignore inbound custom onion messages,
486 /// [`IgnoringMessageHandler`] must be provided to [`OnionMessenger::new`]. Otherwise, a custom
487 /// implementation of this trait must be provided, with [`CustomMessage`] specifying the supported
490 /// See [`OnionMessenger`] for example usage.
492 /// [`IgnoringMessageHandler`]: crate::ln::peer_handler::IgnoringMessageHandler
493 /// [`CustomMessage`]: Self::CustomMessage
494 pub trait CustomOnionMessageHandler {
495 /// The message known to the handler. To support multiple message types, you may want to make this
496 /// an enum with a variant for each supported message.
497 type CustomMessage: OnionMessageContents;
499 /// Called with the custom message that was received, returning a response to send, if any.
501 /// The returned [`Self::CustomMessage`], if any, is enqueued to be sent by [`OnionMessenger`].
502 fn handle_custom_message(&self, msg: Self::CustomMessage) -> Option<Self::CustomMessage>;
504 /// Read a custom message of type `message_type` from `buffer`, returning `Ok(None)` if the
505 /// message type is unknown.
506 fn read_custom_message<R: io::Read>(&self, message_type: u64, buffer: &mut R) -> Result<Option<Self::CustomMessage>, msgs::DecodeError>;
508 /// Releases any [`Self::CustomMessage`]s that need to be sent.
510 /// Typically, this is used for messages initiating a message flow rather than in response to
511 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
512 #[cfg(not(c_bindings))]
513 fn release_pending_custom_messages(&self) -> Vec<PendingOnionMessage<Self::CustomMessage>>;
515 /// Releases any [`Self::CustomMessage`]s that need to be sent.
517 /// Typically, this is used for messages initiating a message flow rather than in response to
518 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
520 fn release_pending_custom_messages(&self) -> Vec<(Self::CustomMessage, Destination, Option<BlindedPath>)>;
523 /// A processed incoming onion message, containing either a Forward (another onion message)
524 /// or a Receive payload with decrypted contents.
525 pub enum PeeledOnion<T: OnionMessageContents> {
526 /// Forwarded onion, with the next node id and a new onion
527 Forward(PublicKey, OnionMessage),
528 /// Received onion message, with decrypted contents, path_id, and reply path
529 Receive(ParsedOnionMessageContents<T>, Option<[u8; 32]>, Option<BlindedPath>)
532 /// Creates an [`OnionMessage`] with the given `contents` for sending to the destination of
535 /// Returns the node id of the peer to send the message to, the message itself, and any addresses
536 /// need to connect to the first node.
537 pub fn create_onion_message<ES: Deref, NS: Deref, T: OnionMessageContents>(
538 entropy_source: &ES, node_signer: &NS, secp_ctx: &Secp256k1<secp256k1::All>,
539 path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
540 ) -> Result<(PublicKey, OnionMessage, Option<Vec<SocketAddress>>), SendError>
542 ES::Target: EntropySource,
543 NS::Target: NodeSigner,
545 let OnionMessagePath { intermediate_nodes, mut destination, first_node_addresses } = path;
546 if let Destination::BlindedPath(BlindedPath { ref blinded_hops, .. }) = destination {
547 if blinded_hops.is_empty() {
548 return Err(SendError::TooFewBlindedHops);
552 if contents.tlv_type() < 64 { return Err(SendError::InvalidMessage) }
554 // If we are sending straight to a blinded path and we are the introduction node, we need to
555 // advance the blinded path by 1 hop so the second hop is the new introduction node.
556 if intermediate_nodes.len() == 0 {
557 if let Destination::BlindedPath(ref mut blinded_path) = destination {
558 let our_node_id = node_signer.get_node_id(Recipient::Node)
559 .map_err(|()| SendError::GetNodeIdFailed)?;
560 if blinded_path.introduction_node_id == our_node_id {
561 advance_path_by_one(blinded_path, node_signer, &secp_ctx)
562 .map_err(|()| SendError::BlindedPathAdvanceFailed)?;
567 let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
568 let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
569 let (first_node_id, blinding_point) = if let Some(first_node_id) = intermediate_nodes.first() {
570 (*first_node_id, PublicKey::from_secret_key(&secp_ctx, &blinding_secret))
573 Destination::Node(pk) => (pk, PublicKey::from_secret_key(&secp_ctx, &blinding_secret)),
574 Destination::BlindedPath(BlindedPath { introduction_node_id, blinding_point, .. }) =>
575 (introduction_node_id, blinding_point),
578 let (packet_payloads, packet_keys) = packet_payloads_and_keys(
579 &secp_ctx, &intermediate_nodes, destination, contents, reply_path, &blinding_secret)
580 .map_err(|e| SendError::Secp256k1(e))?;
582 let prng_seed = entropy_source.get_secure_random_bytes();
583 let onion_routing_packet = construct_onion_message_packet(
584 packet_payloads, packet_keys, prng_seed).map_err(|()| SendError::TooBigPacket)?;
586 let message = OnionMessage { blinding_point, onion_routing_packet };
587 Ok((first_node_id, message, first_node_addresses))
590 /// Decode one layer of an incoming [`OnionMessage`].
592 /// Returns either the next layer of the onion for forwarding or the decrypted content for the
594 pub fn peel_onion_message<NS: Deref, L: Deref, CMH: Deref>(
595 msg: &OnionMessage, secp_ctx: &Secp256k1<secp256k1::All>, node_signer: NS, logger: L,
597 ) -> Result<PeeledOnion<<<CMH>::Target as CustomOnionMessageHandler>::CustomMessage>, ()>
599 NS::Target: NodeSigner,
601 CMH::Target: CustomOnionMessageHandler,
603 let control_tlvs_ss = match node_signer.ecdh(Recipient::Node, &msg.blinding_point, None) {
606 log_error!(logger, "Failed to retrieve node secret: {:?}", e);
610 let onion_decode_ss = {
611 let blinding_factor = {
612 let mut hmac = HmacEngine::<Sha256>::new(b"blinded_node_id");
613 hmac.input(control_tlvs_ss.as_ref());
614 Hmac::from_engine(hmac).to_byte_array()
616 match node_signer.ecdh(Recipient::Node, &msg.onion_routing_packet.public_key,
617 Some(&Scalar::from_be_bytes(blinding_factor).unwrap()))
619 Ok(ss) => ss.secret_bytes(),
621 log_trace!(logger, "Failed to compute onion packet shared secret");
626 match onion_utils::decode_next_untagged_hop(
627 onion_decode_ss, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
628 (control_tlvs_ss, custom_handler.deref(), logger.deref())
630 Ok((Payload::Receive::<ParsedOnionMessageContents<<<CMH as Deref>::Target as CustomOnionMessageHandler>::CustomMessage>> {
631 message, control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id }), reply_path,
633 Ok(PeeledOnion::Receive(message, path_id, reply_path))
635 Ok((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
636 next_node_id, next_blinding_override
637 })), Some((next_hop_hmac, new_packet_bytes)))) => {
638 // TODO: we need to check whether `next_node_id` is our node, in which case this is a dummy
639 // blinded hop and this onion message is destined for us. In this situation, we should keep
640 // unwrapping the onion layers to get to the final payload. Since we don't have the option
641 // of creating blinded paths with dummy hops currently, we should be ok to not handle this
643 let new_pubkey = match onion_utils::next_hop_pubkey(&secp_ctx, msg.onion_routing_packet.public_key, &onion_decode_ss) {
646 log_trace!(logger, "Failed to compute next hop packet pubkey: {}", e);
650 let outgoing_packet = Packet {
652 public_key: new_pubkey,
653 hop_data: new_packet_bytes,
656 let onion_message = OnionMessage {
657 blinding_point: match next_blinding_override {
658 Some(blinding_point) => blinding_point,
660 match onion_utils::next_hop_pubkey(
661 &secp_ctx, msg.blinding_point, control_tlvs_ss.as_ref()
665 log_trace!(logger, "Failed to compute next blinding point: {}", e);
671 onion_routing_packet: outgoing_packet,
674 Ok(PeeledOnion::Forward(next_node_id, onion_message))
677 log_trace!(logger, "Errored decoding onion message packet: {:?}", e);
681 log_trace!(logger, "Received bogus onion message packet, either the sender encoded a final hop as a forwarding hop or vice versa");
687 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref>
688 OnionMessenger<ES, NS, L, MR, OMH, CMH>
690 ES::Target: EntropySource,
691 NS::Target: NodeSigner,
693 MR::Target: MessageRouter,
694 OMH::Target: OffersMessageHandler,
695 CMH::Target: CustomOnionMessageHandler,
697 /// Constructs a new `OnionMessenger` to send, forward, and delegate received onion messages to
698 /// their respective handlers.
700 entropy_source: ES, node_signer: NS, logger: L, message_router: MR, offers_handler: OMH,
703 let mut secp_ctx = Secp256k1::new();
704 secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
708 message_recipients: Mutex::new(HashMap::new()),
717 /// Sends an [`OnionMessage`] with the given `contents` to `destination`.
719 /// See [`OnionMessenger`] for example usage.
720 pub fn send_onion_message<T: OnionMessageContents>(
721 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>
722 ) -> Result<SendSuccess, SendError> {
723 self.find_path_and_enqueue_onion_message(
724 contents, destination, reply_path, format_args!("")
728 fn find_path_and_enqueue_onion_message<T: OnionMessageContents>(
729 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>,
730 log_suffix: fmt::Arguments
731 ) -> Result<SendSuccess, SendError> {
732 let result = self.find_path(destination)
733 .and_then(|path| self.enqueue_onion_message(path, contents, reply_path, log_suffix));
735 match result.as_ref() {
736 Err(SendError::GetNodeIdFailed) => {
737 log_warn!(self.logger, "Unable to retrieve node id {}", log_suffix);
739 Err(SendError::PathNotFound) => {
740 log_trace!(self.logger, "Failed to find path {}", log_suffix);
743 log_trace!(self.logger, "Failed sending onion message {}: {:?}", log_suffix, e);
745 Ok(SendSuccess::Buffered) => {
746 log_trace!(self.logger, "Buffered onion message {}", log_suffix);
748 Ok(SendSuccess::BufferedAwaitingConnection(node_id)) => {
750 self.logger, "Buffered onion message waiting on peer connection {}: {:?}",
759 fn find_path(&self, destination: Destination) -> Result<OnionMessagePath, SendError> {
760 let sender = self.node_signer
761 .get_node_id(Recipient::Node)
762 .map_err(|_| SendError::GetNodeIdFailed)?;
764 let peers = self.message_recipients.lock().unwrap()
766 .filter(|(_, recipient)| matches!(recipient, OnionMessageRecipient::ConnectedPeer(_)))
767 .map(|(node_id, _)| *node_id)
771 .find_path(sender, peers, destination)
772 .map_err(|_| SendError::PathNotFound)
775 fn enqueue_onion_message<T: OnionMessageContents>(
776 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
777 log_suffix: fmt::Arguments
778 ) -> Result<SendSuccess, SendError> {
779 log_trace!(self.logger, "Constructing onion message {}: {:?}", log_suffix, contents);
781 let (first_node_id, onion_message, addresses) = create_onion_message(
782 &self.entropy_source, &self.node_signer, &self.secp_ctx, path, contents, reply_path
785 let mut message_recipients = self.message_recipients.lock().unwrap();
786 if outbound_buffer_full(&first_node_id, &message_recipients) {
787 return Err(SendError::BufferFull);
790 match message_recipients.entry(first_node_id) {
791 hash_map::Entry::Vacant(e) => match addresses {
792 None => Err(SendError::InvalidFirstHop(first_node_id)),
794 e.insert(OnionMessageRecipient::pending_connection(addresses))
795 .enqueue_message(onion_message);
796 Ok(SendSuccess::BufferedAwaitingConnection(first_node_id))
799 hash_map::Entry::Occupied(mut e) => {
800 e.get_mut().enqueue_message(onion_message);
801 if e.get().is_connected() {
802 Ok(SendSuccess::Buffered)
804 Ok(SendSuccess::BufferedAwaitingConnection(first_node_id))
811 pub(super) fn send_onion_message_using_path<T: OnionMessageContents>(
812 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>
813 ) -> Result<SendSuccess, SendError> {
814 self.enqueue_onion_message(path, contents, reply_path, format_args!(""))
817 fn handle_onion_message_response<T: OnionMessageContents>(
818 &self, response: Option<T>, reply_path: Option<BlindedPath>, log_suffix: fmt::Arguments
820 if let Some(response) = response {
822 Some(reply_path) => {
823 let _ = self.find_path_and_enqueue_onion_message(
824 response, Destination::BlindedPath(reply_path), None, log_suffix
828 log_trace!(self.logger, "Missing reply path {}", log_suffix);
835 pub(super) fn release_pending_msgs(&self) -> HashMap<PublicKey, VecDeque<OnionMessage>> {
836 let mut message_recipients = self.message_recipients.lock().unwrap();
837 let mut msgs = HashMap::new();
838 // We don't want to disconnect the peers by removing them entirely from the original map, so we
839 // release the pending message buffers individually.
840 for (node_id, recipient) in &mut *message_recipients {
841 msgs.insert(*node_id, recipient.release_pending_messages());
847 fn outbound_buffer_full(peer_node_id: &PublicKey, buffer: &HashMap<PublicKey, OnionMessageRecipient>) -> bool {
848 const MAX_TOTAL_BUFFER_SIZE: usize = (1 << 20) * 128;
849 const MAX_PER_PEER_BUFFER_SIZE: usize = (1 << 10) * 256;
850 let mut total_buffered_bytes = 0;
851 let mut peer_buffered_bytes = 0;
852 for (pk, peer_buf) in buffer {
853 for om in peer_buf.pending_messages() {
854 let om_len = om.serialized_length();
855 if pk == peer_node_id {
856 peer_buffered_bytes += om_len;
858 total_buffered_bytes += om_len;
860 if total_buffered_bytes >= MAX_TOTAL_BUFFER_SIZE ||
861 peer_buffered_bytes >= MAX_PER_PEER_BUFFER_SIZE
870 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref> EventsProvider
871 for OnionMessenger<ES, NS, L, MR, OMH, CMH>
873 ES::Target: EntropySource,
874 NS::Target: NodeSigner,
876 MR::Target: MessageRouter,
877 OMH::Target: OffersMessageHandler,
878 CMH::Target: CustomOnionMessageHandler,
880 fn process_pending_events<H: Deref>(&self, handler: H) where H::Target: EventHandler {
881 for (node_id, recipient) in self.message_recipients.lock().unwrap().iter_mut() {
882 if let OnionMessageRecipient::PendingConnection(_, addresses, _) = recipient {
883 if let Some(addresses) = addresses.take() {
884 handler.handle_event(Event::ConnectionNeeded { node_id: *node_id, addresses });
891 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref> OnionMessageHandler
892 for OnionMessenger<ES, NS, L, MR, OMH, CMH>
894 ES::Target: EntropySource,
895 NS::Target: NodeSigner,
897 MR::Target: MessageRouter,
898 OMH::Target: OffersMessageHandler,
899 CMH::Target: CustomOnionMessageHandler,
901 fn handle_onion_message(&self, _peer_node_id: &PublicKey, msg: &OnionMessage) {
902 match peel_onion_message(
903 msg, &self.secp_ctx, &*self.node_signer, &*self.logger, &*self.custom_handler
905 Ok(PeeledOnion::Receive(message, path_id, reply_path)) => {
908 "Received an onion message with path_id {:02x?} and {} reply_path: {:?}",
909 path_id, if reply_path.is_some() { "a" } else { "no" }, message);
912 ParsedOnionMessageContents::Offers(msg) => {
913 let response = self.offers_handler.handle_message(msg);
914 self.handle_onion_message_response(
915 response, reply_path, format_args!(
916 "when responding to Offers onion message with path_id {:02x?}",
921 ParsedOnionMessageContents::Custom(msg) => {
922 let response = self.custom_handler.handle_custom_message(msg);
923 self.handle_onion_message_response(
924 response, reply_path, format_args!(
925 "when responding to Custom onion message with path_id {:02x?}",
932 Ok(PeeledOnion::Forward(next_node_id, onion_message)) => {
933 let mut message_recipients = self.message_recipients.lock().unwrap();
934 if outbound_buffer_full(&next_node_id, &message_recipients) {
935 log_trace!(self.logger, "Dropping forwarded onion message to peer {:?}: outbound buffer full", next_node_id);
942 .or_insert_with(|| OnionMessageRecipient::ConnectedPeer(VecDeque::new()));
944 match message_recipients.entry(next_node_id) {
945 hash_map::Entry::Occupied(mut e) if matches!(
946 e.get(), OnionMessageRecipient::ConnectedPeer(..)
948 e.get_mut().enqueue_message(onion_message);
949 log_trace!(self.logger, "Forwarding an onion message to peer {}", next_node_id);
952 log_trace!(self.logger, "Dropping forwarded onion message to disconnected peer {:?}", next_node_id);
958 log_error!(self.logger, "Failed to process onion message {:?}", e);
963 fn peer_connected(&self, their_node_id: &PublicKey, init: &msgs::Init, _inbound: bool) -> Result<(), ()> {
964 if init.features.supports_onion_messages() {
965 self.message_recipients.lock().unwrap()
966 .entry(*their_node_id)
967 .or_insert_with(|| OnionMessageRecipient::ConnectedPeer(VecDeque::new()))
970 self.message_recipients.lock().unwrap().remove(their_node_id);
976 fn peer_disconnected(&self, their_node_id: &PublicKey) {
977 match self.message_recipients.lock().unwrap().remove(their_node_id) {
978 Some(OnionMessageRecipient::ConnectedPeer(..)) => {},
979 Some(_) => debug_assert!(false),
984 fn timer_tick_occurred(&self) {
985 let mut message_recipients = self.message_recipients.lock().unwrap();
987 // Drop any pending recipients since the last call to avoid retaining buffered messages for
989 message_recipients.retain(|_, recipient| match recipient {
990 OnionMessageRecipient::PendingConnection(_, None, ticks) => *ticks < MAX_TIMER_TICKS,
991 OnionMessageRecipient::PendingConnection(_, Some(_), _) => true,
995 // Increment a timer tick for pending recipients so that their buffered messages are dropped
996 // at MAX_TIMER_TICKS.
997 for recipient in message_recipients.values_mut() {
998 if let OnionMessageRecipient::PendingConnection(_, None, ticks) = recipient {
1004 fn provided_node_features(&self) -> NodeFeatures {
1005 let mut features = NodeFeatures::empty();
1006 features.set_onion_messages_optional();
1010 fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
1011 let mut features = InitFeatures::empty();
1012 features.set_onion_messages_optional();
1016 // Before returning any messages to send for the peer, this method will see if any messages were
1017 // enqueued in the handler by users, find a path to the corresponding blinded path's introduction
1018 // node, and then enqueue the message for sending to the first peer in the full path.
1019 fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<OnionMessage> {
1020 // Enqueue any initiating `OffersMessage`s to send.
1021 for message in self.offers_handler.release_pending_messages() {
1022 #[cfg(not(c_bindings))]
1023 let PendingOnionMessage { contents, destination, reply_path } = message;
1025 let (contents, destination, reply_path) = message;
1026 let _ = self.find_path_and_enqueue_onion_message(
1027 contents, destination, reply_path, format_args!("when sending OffersMessage")
1031 // Enqueue any initiating `CustomMessage`s to send.
1032 for message in self.custom_handler.release_pending_custom_messages() {
1033 #[cfg(not(c_bindings))]
1034 let PendingOnionMessage { contents, destination, reply_path } = message;
1036 let (contents, destination, reply_path) = message;
1037 let _ = self.find_path_and_enqueue_onion_message(
1038 contents, destination, reply_path, format_args!("when sending CustomMessage")
1042 self.message_recipients.lock().unwrap()
1043 .get_mut(&peer_node_id)
1044 .and_then(|buffer| buffer.dequeue_message())
1048 // TODO: parameterize the below Simple* types with OnionMessenger and handle the messages it
1050 /// Useful for simplifying the parameters of [`SimpleArcChannelManager`] and
1051 /// [`SimpleArcPeerManager`]. See their docs for more details.
1053 /// This is not exported to bindings users as type aliases aren't supported in most languages.
1055 /// [`SimpleArcChannelManager`]: crate::ln::channelmanager::SimpleArcChannelManager
1056 /// [`SimpleArcPeerManager`]: crate::ln::peer_handler::SimpleArcPeerManager
1057 #[cfg(not(c_bindings))]
1058 pub type SimpleArcOnionMessenger<M, T, F, L> = OnionMessenger<
1062 Arc<DefaultMessageRouter<Arc<NetworkGraph<Arc<L>>>, Arc<L>>>,
1063 Arc<SimpleArcChannelManager<M, T, F, L>>,
1064 IgnoringMessageHandler
1067 /// Useful for simplifying the parameters of [`SimpleRefChannelManager`] and
1068 /// [`SimpleRefPeerManager`]. See their docs for more details.
1070 /// This is not exported to bindings users as type aliases aren't supported in most languages.
1072 /// [`SimpleRefChannelManager`]: crate::ln::channelmanager::SimpleRefChannelManager
1073 /// [`SimpleRefPeerManager`]: crate::ln::peer_handler::SimpleRefPeerManager
1074 #[cfg(not(c_bindings))]
1075 pub type SimpleRefOnionMessenger<
1076 'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, 'i, 'j, M, T, F, L
1081 &'i DefaultMessageRouter<&'g NetworkGraph<&'b L>, &'b L>,
1082 &'j SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, M, T, F, L>,
1083 IgnoringMessageHandler
1086 /// Construct onion packet payloads and keys for sending an onion message along the given
1087 /// `unblinded_path` to the given `destination`.
1088 fn packet_payloads_and_keys<T: OnionMessageContents, S: secp256k1::Signing + secp256k1::Verification>(
1089 secp_ctx: &Secp256k1<S>, unblinded_path: &[PublicKey], destination: Destination, message: T,
1090 mut reply_path: Option<BlindedPath>, session_priv: &SecretKey
1091 ) -> Result<(Vec<(Payload<T>, [u8; 32])>, Vec<onion_utils::OnionKeys>), secp256k1::Error> {
1092 let num_hops = unblinded_path.len() + destination.num_hops();
1093 let mut payloads = Vec::with_capacity(num_hops);
1094 let mut onion_packet_keys = Vec::with_capacity(num_hops);
1096 let (mut intro_node_id_blinding_pt, num_blinded_hops) = if let Destination::BlindedPath(BlindedPath {
1097 introduction_node_id, blinding_point, blinded_hops }) = &destination {
1098 (Some((*introduction_node_id, *blinding_point)), blinded_hops.len()) } else { (None, 0) };
1099 let num_unblinded_hops = num_hops - num_blinded_hops;
1101 let mut unblinded_path_idx = 0;
1102 let mut blinded_path_idx = 0;
1103 let mut prev_control_tlvs_ss = None;
1104 let mut final_control_tlvs = None;
1105 utils::construct_keys_callback(secp_ctx, unblinded_path.iter(), Some(destination), session_priv,
1106 |_, onion_packet_ss, ephemeral_pubkey, control_tlvs_ss, unblinded_pk_opt, enc_payload_opt| {
1107 if num_unblinded_hops != 0 && unblinded_path_idx < num_unblinded_hops {
1108 if let Some(ss) = prev_control_tlvs_ss.take() {
1109 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(
1111 next_node_id: unblinded_pk_opt.unwrap(),
1112 next_blinding_override: None,
1116 prev_control_tlvs_ss = Some(control_tlvs_ss);
1117 unblinded_path_idx += 1;
1118 } else if let Some((intro_node_id, blinding_pt)) = intro_node_id_blinding_pt.take() {
1119 if let Some(control_tlvs_ss) = prev_control_tlvs_ss.take() {
1120 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
1121 next_node_id: intro_node_id,
1122 next_blinding_override: Some(blinding_pt),
1123 })), control_tlvs_ss));
1126 if blinded_path_idx < num_blinded_hops.saturating_sub(1) && enc_payload_opt.is_some() {
1127 payloads.push((Payload::Forward(ForwardControlTlvs::Blinded(enc_payload_opt.unwrap())),
1129 blinded_path_idx += 1;
1130 } else if let Some(encrypted_payload) = enc_payload_opt {
1131 final_control_tlvs = Some(ReceiveControlTlvs::Blinded(encrypted_payload));
1132 prev_control_tlvs_ss = Some(control_tlvs_ss);
1135 let (rho, mu) = onion_utils::gen_rho_mu_from_shared_secret(onion_packet_ss.as_ref());
1136 onion_packet_keys.push(onion_utils::OnionKeys {
1138 shared_secret: onion_packet_ss,
1140 blinding_factor: [0; 32],
1148 if let Some(control_tlvs) = final_control_tlvs {
1149 payloads.push((Payload::Receive {
1151 reply_path: reply_path.take(),
1153 }, prev_control_tlvs_ss.unwrap()));
1155 payloads.push((Payload::Receive {
1156 control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id: None, }),
1157 reply_path: reply_path.take(),
1159 }, prev_control_tlvs_ss.unwrap()));
1162 Ok((payloads, onion_packet_keys))
1165 /// Errors if the serialized payload size exceeds onion_message::BIG_PACKET_HOP_DATA_LEN
1166 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, ()> {
1168 // "`len` allows larger messages to be sent than the standard 1300 bytes allowed for an HTLC
1169 // onion, but this should be used sparingly as it is reduces anonymity set, hence the
1170 // recommendation that it either look like an HTLC onion, or if larger, be a fixed size."
1171 let payloads_ser_len = onion_utils::payloads_serialized_length(&payloads);
1172 let hop_data_len = if payloads_ser_len <= SMALL_PACKET_HOP_DATA_LEN {
1173 SMALL_PACKET_HOP_DATA_LEN
1174 } else if payloads_ser_len <= BIG_PACKET_HOP_DATA_LEN {
1175 BIG_PACKET_HOP_DATA_LEN
1176 } else { return Err(()) };
1178 onion_utils::construct_onion_message_packet::<_, _>(
1179 payloads, onion_keys, prng_seed, hop_data_len)