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<T: secp256k1::Signing + secp256k1::Verification>(
101 /// # &self, _recipient: PublicKey, _peers: Vec<PublicKey>, _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 T: secp256k1::Signing + secp256k1::Verification
291 &self, recipient: PublicKey, peers: Vec<PublicKey>, secp_ctx: &Secp256k1<T>,
292 ) -> Result<Vec<BlindedPath>, ()>;
295 /// A [`MessageRouter`] that can only route to a directly connected [`Destination`].
296 pub struct DefaultMessageRouter<G: Deref<Target=NetworkGraph<L>>, L: Deref, ES: Deref>
299 ES::Target: EntropySource,
305 impl<G: Deref<Target=NetworkGraph<L>>, L: Deref, ES: Deref> DefaultMessageRouter<G, L, ES>
308 ES::Target: EntropySource,
310 /// Creates a [`DefaultMessageRouter`] using the given [`NetworkGraph`].
311 pub fn new(network_graph: G, entropy_source: ES) -> Self {
312 Self { network_graph, entropy_source }
316 impl<G: Deref<Target=NetworkGraph<L>>, L: Deref, ES: Deref> DefaultMessageRouter<G, L, ES>
319 ES::Target: EntropySource,
321 pub(crate) fn find_path(
322 network_graph: &G, _sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
323 ) -> Result<OnionMessagePath, ()> {
324 let first_node = destination.first_node();
325 if peers.contains(&first_node) {
326 Ok(OnionMessagePath {
327 intermediate_nodes: vec![], destination, first_node_addresses: None
330 let network_graph = network_graph.deref().read_only();
331 let node_announcement = network_graph
332 .node(&NodeId::from_pubkey(&first_node))
333 .and_then(|node_info| node_info.announcement_info.as_ref())
334 .and_then(|announcement_info| announcement_info.announcement_message.as_ref())
335 .map(|node_announcement| &node_announcement.contents);
337 match node_announcement {
338 Some(node_announcement) if node_announcement.features.supports_onion_messages() => {
339 let first_node_addresses = Some(node_announcement.addresses.clone());
340 Ok(OnionMessagePath {
341 intermediate_nodes: vec![], destination, first_node_addresses
349 pub(crate) fn create_blinded_paths<
350 T: secp256k1::Signing + secp256k1::Verification
352 network_graph: &G, recipient: PublicKey, peers: Vec<PublicKey>, entropy_source: &ES,
353 secp_ctx: &Secp256k1<T>,
354 ) -> Result<Vec<BlindedPath>, ()> {
355 // Limit the number of blinded paths that are computed.
356 const MAX_PATHS: usize = 3;
358 // Ensure peers have at least three channels so that it is more difficult to infer the
359 // recipient's node_id.
360 const MIN_PEER_CHANNELS: usize = 3;
362 let network_graph = network_graph.deref().read_only();
363 let paths = peers.iter()
364 // Limit to peers with announced channels
367 .node(&NodeId::from_pubkey(pubkey))
368 .map(|info| &info.channels[..])
369 .map(|channels| channels.len() >= MIN_PEER_CHANNELS)
372 .map(|pubkey| vec![*pubkey, recipient])
373 .map(|node_pks| BlindedPath::new_for_message(&node_pks, &**entropy_source, secp_ctx))
375 .collect::<Result<Vec<_>, _>>();
378 Ok(paths) if !paths.is_empty() => Ok(paths),
380 if network_graph.nodes().contains_key(&NodeId::from_pubkey(&recipient)) {
381 BlindedPath::one_hop_for_message(recipient, &**entropy_source, secp_ctx)
382 .map(|path| vec![path])
391 impl<G: Deref<Target=NetworkGraph<L>>, L: Deref, ES: Deref> MessageRouter for DefaultMessageRouter<G, L, ES>
394 ES::Target: EntropySource,
397 &self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
398 ) -> Result<OnionMessagePath, ()> {
399 Self::find_path(&self.network_graph, sender, peers, destination)
402 fn create_blinded_paths<
403 T: secp256k1::Signing + secp256k1::Verification
405 &self, recipient: PublicKey, peers: Vec<PublicKey>, secp_ctx: &Secp256k1<T>,
406 ) -> Result<Vec<BlindedPath>, ()> {
407 Self::create_blinded_paths(&self.network_graph, recipient, peers, &self.entropy_source, secp_ctx)
411 /// A path for sending an [`OnionMessage`].
413 pub struct OnionMessagePath {
414 /// Nodes on the path between the sender and the destination.
415 pub intermediate_nodes: Vec<PublicKey>,
417 /// The recipient of the message.
418 pub destination: Destination,
420 /// Addresses that may be used to connect to [`OnionMessagePath::first_node`].
422 /// Only needs to be set if a connection to the node is required. [`OnionMessenger`] may use
423 /// this to initiate such a connection.
424 pub first_node_addresses: Option<Vec<SocketAddress>>,
427 impl OnionMessagePath {
428 /// Returns the first node in the path.
429 pub fn first_node(&self) -> PublicKey {
430 self.intermediate_nodes
433 .unwrap_or_else(|| self.destination.first_node())
437 /// The destination of an onion message.
439 pub enum Destination {
440 /// We're sending this onion message to a node.
442 /// We're sending this onion message to a blinded path.
443 BlindedPath(BlindedPath),
447 pub(super) fn num_hops(&self) -> usize {
449 Destination::Node(_) => 1,
450 Destination::BlindedPath(BlindedPath { blinded_hops, .. }) => blinded_hops.len(),
454 fn first_node(&self) -> PublicKey {
456 Destination::Node(node_id) => *node_id,
457 Destination::BlindedPath(BlindedPath { introduction_node_id: node_id, .. }) => *node_id,
462 /// Result of successfully [sending an onion message].
464 /// [sending an onion message]: OnionMessenger::send_onion_message
465 #[derive(Debug, PartialEq, Eq)]
466 pub enum SendSuccess {
467 /// The message was buffered and will be sent once it is processed by
468 /// [`OnionMessageHandler::next_onion_message_for_peer`].
470 /// The message was buffered and will be sent once the node is connected as a peer and it is
471 /// processed by [`OnionMessageHandler::next_onion_message_for_peer`].
472 BufferedAwaitingConnection(PublicKey),
475 /// Errors that may occur when [sending an onion message].
477 /// [sending an onion message]: OnionMessenger::send_onion_message
478 #[derive(Debug, PartialEq, Eq)]
480 /// Errored computing onion message packet keys.
481 Secp256k1(secp256k1::Error),
482 /// Because implementations such as Eclair will drop onion messages where the message packet
483 /// exceeds 32834 bytes, we refuse to send messages where the packet exceeds this size.
485 /// The provided [`Destination`] was an invalid [`BlindedPath`] due to not having any blinded
488 /// The first hop is not a peer and doesn't have a known [`SocketAddress`].
489 InvalidFirstHop(PublicKey),
490 /// A path from the sender to the destination could not be found by the [`MessageRouter`].
492 /// Onion message contents must have a TLV type >= 64.
494 /// Our next-hop peer's buffer was full or our total outbound buffer was full.
496 /// Failed to retrieve our node id from the provided [`NodeSigner`].
498 /// [`NodeSigner`]: crate::sign::NodeSigner
500 /// We attempted to send to a blinded path where we are the introduction node, and failed to
501 /// advance the blinded path to make the second hop the new introduction node. Either
502 /// [`NodeSigner::ecdh`] failed, we failed to tweak the current blinding point to get the
503 /// new blinding point, or we were attempting to send to ourselves.
504 BlindedPathAdvanceFailed,
507 /// Handler for custom onion messages. If you are using [`SimpleArcOnionMessenger`],
508 /// [`SimpleRefOnionMessenger`], or prefer to ignore inbound custom onion messages,
509 /// [`IgnoringMessageHandler`] must be provided to [`OnionMessenger::new`]. Otherwise, a custom
510 /// implementation of this trait must be provided, with [`CustomMessage`] specifying the supported
513 /// See [`OnionMessenger`] for example usage.
515 /// [`IgnoringMessageHandler`]: crate::ln::peer_handler::IgnoringMessageHandler
516 /// [`CustomMessage`]: Self::CustomMessage
517 pub trait CustomOnionMessageHandler {
518 /// The message known to the handler. To support multiple message types, you may want to make this
519 /// an enum with a variant for each supported message.
520 type CustomMessage: OnionMessageContents;
522 /// Called with the custom message that was received, returning a response to send, if any.
524 /// The returned [`Self::CustomMessage`], if any, is enqueued to be sent by [`OnionMessenger`].
525 fn handle_custom_message(&self, msg: Self::CustomMessage) -> Option<Self::CustomMessage>;
527 /// Read a custom message of type `message_type` from `buffer`, returning `Ok(None)` if the
528 /// message type is unknown.
529 fn read_custom_message<R: io::Read>(&self, message_type: u64, buffer: &mut R) -> Result<Option<Self::CustomMessage>, msgs::DecodeError>;
531 /// Releases any [`Self::CustomMessage`]s that need to be sent.
533 /// Typically, this is used for messages initiating a message flow rather than in response to
534 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
535 #[cfg(not(c_bindings))]
536 fn release_pending_custom_messages(&self) -> Vec<PendingOnionMessage<Self::CustomMessage>>;
538 /// Releases any [`Self::CustomMessage`]s that need to be sent.
540 /// Typically, this is used for messages initiating a message flow rather than in response to
541 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
543 fn release_pending_custom_messages(&self) -> Vec<(Self::CustomMessage, Destination, Option<BlindedPath>)>;
546 /// A processed incoming onion message, containing either a Forward (another onion message)
547 /// or a Receive payload with decrypted contents.
548 pub enum PeeledOnion<T: OnionMessageContents> {
549 /// Forwarded onion, with the next node id and a new onion
550 Forward(PublicKey, OnionMessage),
551 /// Received onion message, with decrypted contents, path_id, and reply path
552 Receive(ParsedOnionMessageContents<T>, Option<[u8; 32]>, Option<BlindedPath>)
555 /// Creates an [`OnionMessage`] with the given `contents` for sending to the destination of
558 /// Returns the node id of the peer to send the message to, the message itself, and any addresses
559 /// need to connect to the first node.
560 pub fn create_onion_message<ES: Deref, NS: Deref, T: OnionMessageContents>(
561 entropy_source: &ES, node_signer: &NS, secp_ctx: &Secp256k1<secp256k1::All>,
562 path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
563 ) -> Result<(PublicKey, OnionMessage, Option<Vec<SocketAddress>>), SendError>
565 ES::Target: EntropySource,
566 NS::Target: NodeSigner,
568 let OnionMessagePath { intermediate_nodes, mut destination, first_node_addresses } = path;
569 if let Destination::BlindedPath(BlindedPath { ref blinded_hops, .. }) = destination {
570 if blinded_hops.is_empty() {
571 return Err(SendError::TooFewBlindedHops);
575 if contents.tlv_type() < 64 { return Err(SendError::InvalidMessage) }
577 // If we are sending straight to a blinded path and we are the introduction node, we need to
578 // advance the blinded path by 1 hop so the second hop is the new introduction node.
579 if intermediate_nodes.len() == 0 {
580 if let Destination::BlindedPath(ref mut blinded_path) = destination {
581 let our_node_id = node_signer.get_node_id(Recipient::Node)
582 .map_err(|()| SendError::GetNodeIdFailed)?;
583 if blinded_path.introduction_node_id == our_node_id {
584 advance_path_by_one(blinded_path, node_signer, &secp_ctx)
585 .map_err(|()| SendError::BlindedPathAdvanceFailed)?;
590 let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
591 let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
592 let (first_node_id, blinding_point) = if let Some(first_node_id) = intermediate_nodes.first() {
593 (*first_node_id, PublicKey::from_secret_key(&secp_ctx, &blinding_secret))
596 Destination::Node(pk) => (pk, PublicKey::from_secret_key(&secp_ctx, &blinding_secret)),
597 Destination::BlindedPath(BlindedPath { introduction_node_id, blinding_point, .. }) =>
598 (introduction_node_id, blinding_point),
601 let (packet_payloads, packet_keys) = packet_payloads_and_keys(
602 &secp_ctx, &intermediate_nodes, destination, contents, reply_path, &blinding_secret)
603 .map_err(|e| SendError::Secp256k1(e))?;
605 let prng_seed = entropy_source.get_secure_random_bytes();
606 let onion_routing_packet = construct_onion_message_packet(
607 packet_payloads, packet_keys, prng_seed).map_err(|()| SendError::TooBigPacket)?;
609 let message = OnionMessage { blinding_point, onion_routing_packet };
610 Ok((first_node_id, message, first_node_addresses))
613 /// Decode one layer of an incoming [`OnionMessage`].
615 /// Returns either the next layer of the onion for forwarding or the decrypted content for the
617 pub fn peel_onion_message<NS: Deref, L: Deref, CMH: Deref>(
618 msg: &OnionMessage, secp_ctx: &Secp256k1<secp256k1::All>, node_signer: NS, logger: L,
620 ) -> Result<PeeledOnion<<<CMH>::Target as CustomOnionMessageHandler>::CustomMessage>, ()>
622 NS::Target: NodeSigner,
624 CMH::Target: CustomOnionMessageHandler,
626 let control_tlvs_ss = match node_signer.ecdh(Recipient::Node, &msg.blinding_point, None) {
629 log_error!(logger, "Failed to retrieve node secret: {:?}", e);
633 let onion_decode_ss = {
634 let blinding_factor = {
635 let mut hmac = HmacEngine::<Sha256>::new(b"blinded_node_id");
636 hmac.input(control_tlvs_ss.as_ref());
637 Hmac::from_engine(hmac).to_byte_array()
639 match node_signer.ecdh(Recipient::Node, &msg.onion_routing_packet.public_key,
640 Some(&Scalar::from_be_bytes(blinding_factor).unwrap()))
642 Ok(ss) => ss.secret_bytes(),
644 log_trace!(logger, "Failed to compute onion packet shared secret");
649 match onion_utils::decode_next_untagged_hop(
650 onion_decode_ss, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
651 (control_tlvs_ss, custom_handler.deref(), logger.deref())
653 Ok((Payload::Receive::<ParsedOnionMessageContents<<<CMH as Deref>::Target as CustomOnionMessageHandler>::CustomMessage>> {
654 message, control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id }), reply_path,
656 Ok(PeeledOnion::Receive(message, path_id, reply_path))
658 Ok((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
659 next_node_id, next_blinding_override
660 })), Some((next_hop_hmac, new_packet_bytes)))) => {
661 // TODO: we need to check whether `next_node_id` is our node, in which case this is a dummy
662 // blinded hop and this onion message is destined for us. In this situation, we should keep
663 // unwrapping the onion layers to get to the final payload. Since we don't have the option
664 // of creating blinded paths with dummy hops currently, we should be ok to not handle this
666 let new_pubkey = match onion_utils::next_hop_pubkey(&secp_ctx, msg.onion_routing_packet.public_key, &onion_decode_ss) {
669 log_trace!(logger, "Failed to compute next hop packet pubkey: {}", e);
673 let outgoing_packet = Packet {
675 public_key: new_pubkey,
676 hop_data: new_packet_bytes,
679 let onion_message = OnionMessage {
680 blinding_point: match next_blinding_override {
681 Some(blinding_point) => blinding_point,
683 match onion_utils::next_hop_pubkey(
684 &secp_ctx, msg.blinding_point, control_tlvs_ss.as_ref()
688 log_trace!(logger, "Failed to compute next blinding point: {}", e);
694 onion_routing_packet: outgoing_packet,
697 Ok(PeeledOnion::Forward(next_node_id, onion_message))
700 log_trace!(logger, "Errored decoding onion message packet: {:?}", e);
704 log_trace!(logger, "Received bogus onion message packet, either the sender encoded a final hop as a forwarding hop or vice versa");
710 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref>
711 OnionMessenger<ES, NS, L, MR, OMH, CMH>
713 ES::Target: EntropySource,
714 NS::Target: NodeSigner,
716 MR::Target: MessageRouter,
717 OMH::Target: OffersMessageHandler,
718 CMH::Target: CustomOnionMessageHandler,
720 /// Constructs a new `OnionMessenger` to send, forward, and delegate received onion messages to
721 /// their respective handlers.
723 entropy_source: ES, node_signer: NS, logger: L, message_router: MR, offers_handler: OMH,
726 let mut secp_ctx = Secp256k1::new();
727 secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
731 message_recipients: Mutex::new(HashMap::new()),
740 /// Sends an [`OnionMessage`] with the given `contents` to `destination`.
742 /// See [`OnionMessenger`] for example usage.
743 pub fn send_onion_message<T: OnionMessageContents>(
744 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>
745 ) -> Result<SendSuccess, SendError> {
746 self.find_path_and_enqueue_onion_message(
747 contents, destination, reply_path, format_args!("")
751 fn find_path_and_enqueue_onion_message<T: OnionMessageContents>(
752 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>,
753 log_suffix: fmt::Arguments
754 ) -> Result<SendSuccess, SendError> {
755 let result = self.find_path(destination)
756 .and_then(|path| self.enqueue_onion_message(path, contents, reply_path, log_suffix));
758 match result.as_ref() {
759 Err(SendError::GetNodeIdFailed) => {
760 log_warn!(self.logger, "Unable to retrieve node id {}", log_suffix);
762 Err(SendError::PathNotFound) => {
763 log_trace!(self.logger, "Failed to find path {}", log_suffix);
766 log_trace!(self.logger, "Failed sending onion message {}: {:?}", log_suffix, e);
768 Ok(SendSuccess::Buffered) => {
769 log_trace!(self.logger, "Buffered onion message {}", log_suffix);
771 Ok(SendSuccess::BufferedAwaitingConnection(node_id)) => {
773 self.logger, "Buffered onion message waiting on peer connection {}: {:?}",
782 fn find_path(&self, destination: Destination) -> Result<OnionMessagePath, SendError> {
783 let sender = self.node_signer
784 .get_node_id(Recipient::Node)
785 .map_err(|_| SendError::GetNodeIdFailed)?;
787 let peers = self.message_recipients.lock().unwrap()
789 .filter(|(_, recipient)| matches!(recipient, OnionMessageRecipient::ConnectedPeer(_)))
790 .map(|(node_id, _)| *node_id)
794 .find_path(sender, peers, destination)
795 .map_err(|_| SendError::PathNotFound)
798 fn enqueue_onion_message<T: OnionMessageContents>(
799 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
800 log_suffix: fmt::Arguments
801 ) -> Result<SendSuccess, SendError> {
802 log_trace!(self.logger, "Constructing onion message {}: {:?}", log_suffix, contents);
804 let (first_node_id, onion_message, addresses) = create_onion_message(
805 &self.entropy_source, &self.node_signer, &self.secp_ctx, path, contents, reply_path
808 let mut message_recipients = self.message_recipients.lock().unwrap();
809 if outbound_buffer_full(&first_node_id, &message_recipients) {
810 return Err(SendError::BufferFull);
813 match message_recipients.entry(first_node_id) {
814 hash_map::Entry::Vacant(e) => match addresses {
815 None => Err(SendError::InvalidFirstHop(first_node_id)),
817 e.insert(OnionMessageRecipient::pending_connection(addresses))
818 .enqueue_message(onion_message);
819 Ok(SendSuccess::BufferedAwaitingConnection(first_node_id))
822 hash_map::Entry::Occupied(mut e) => {
823 e.get_mut().enqueue_message(onion_message);
824 if e.get().is_connected() {
825 Ok(SendSuccess::Buffered)
827 Ok(SendSuccess::BufferedAwaitingConnection(first_node_id))
834 pub(super) fn send_onion_message_using_path<T: OnionMessageContents>(
835 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>
836 ) -> Result<SendSuccess, SendError> {
837 self.enqueue_onion_message(path, contents, reply_path, format_args!(""))
840 fn handle_onion_message_response<T: OnionMessageContents>(
841 &self, response: Option<T>, reply_path: Option<BlindedPath>, log_suffix: fmt::Arguments
843 if let Some(response) = response {
845 Some(reply_path) => {
846 let _ = self.find_path_and_enqueue_onion_message(
847 response, Destination::BlindedPath(reply_path), None, log_suffix
851 log_trace!(self.logger, "Missing reply path {}", log_suffix);
858 pub(super) fn release_pending_msgs(&self) -> HashMap<PublicKey, VecDeque<OnionMessage>> {
859 let mut message_recipients = self.message_recipients.lock().unwrap();
860 let mut msgs = HashMap::new();
861 // We don't want to disconnect the peers by removing them entirely from the original map, so we
862 // release the pending message buffers individually.
863 for (node_id, recipient) in &mut *message_recipients {
864 msgs.insert(*node_id, recipient.release_pending_messages());
870 fn outbound_buffer_full(peer_node_id: &PublicKey, buffer: &HashMap<PublicKey, OnionMessageRecipient>) -> bool {
871 const MAX_TOTAL_BUFFER_SIZE: usize = (1 << 20) * 128;
872 const MAX_PER_PEER_BUFFER_SIZE: usize = (1 << 10) * 256;
873 let mut total_buffered_bytes = 0;
874 let mut peer_buffered_bytes = 0;
875 for (pk, peer_buf) in buffer {
876 for om in peer_buf.pending_messages() {
877 let om_len = om.serialized_length();
878 if pk == peer_node_id {
879 peer_buffered_bytes += om_len;
881 total_buffered_bytes += om_len;
883 if total_buffered_bytes >= MAX_TOTAL_BUFFER_SIZE ||
884 peer_buffered_bytes >= MAX_PER_PEER_BUFFER_SIZE
893 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref> EventsProvider
894 for OnionMessenger<ES, NS, L, MR, OMH, CMH>
896 ES::Target: EntropySource,
897 NS::Target: NodeSigner,
899 MR::Target: MessageRouter,
900 OMH::Target: OffersMessageHandler,
901 CMH::Target: CustomOnionMessageHandler,
903 fn process_pending_events<H: Deref>(&self, handler: H) where H::Target: EventHandler {
904 for (node_id, recipient) in self.message_recipients.lock().unwrap().iter_mut() {
905 if let OnionMessageRecipient::PendingConnection(_, addresses, _) = recipient {
906 if let Some(addresses) = addresses.take() {
907 handler.handle_event(Event::ConnectionNeeded { node_id: *node_id, addresses });
914 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref> OnionMessageHandler
915 for OnionMessenger<ES, NS, L, MR, OMH, CMH>
917 ES::Target: EntropySource,
918 NS::Target: NodeSigner,
920 MR::Target: MessageRouter,
921 OMH::Target: OffersMessageHandler,
922 CMH::Target: CustomOnionMessageHandler,
924 fn handle_onion_message(&self, _peer_node_id: &PublicKey, msg: &OnionMessage) {
925 match peel_onion_message(
926 msg, &self.secp_ctx, &*self.node_signer, &*self.logger, &*self.custom_handler
928 Ok(PeeledOnion::Receive(message, path_id, reply_path)) => {
931 "Received an onion message with path_id {:02x?} and {} reply_path: {:?}",
932 path_id, if reply_path.is_some() { "a" } else { "no" }, message);
935 ParsedOnionMessageContents::Offers(msg) => {
936 let response = self.offers_handler.handle_message(msg);
937 self.handle_onion_message_response(
938 response, reply_path, format_args!(
939 "when responding to Offers onion message with path_id {:02x?}",
944 ParsedOnionMessageContents::Custom(msg) => {
945 let response = self.custom_handler.handle_custom_message(msg);
946 self.handle_onion_message_response(
947 response, reply_path, format_args!(
948 "when responding to Custom onion message with path_id {:02x?}",
955 Ok(PeeledOnion::Forward(next_node_id, onion_message)) => {
956 let mut message_recipients = self.message_recipients.lock().unwrap();
957 if outbound_buffer_full(&next_node_id, &message_recipients) {
958 log_trace!(self.logger, "Dropping forwarded onion message to peer {:?}: outbound buffer full", next_node_id);
965 .or_insert_with(|| OnionMessageRecipient::ConnectedPeer(VecDeque::new()));
967 match message_recipients.entry(next_node_id) {
968 hash_map::Entry::Occupied(mut e) if matches!(
969 e.get(), OnionMessageRecipient::ConnectedPeer(..)
971 e.get_mut().enqueue_message(onion_message);
972 log_trace!(self.logger, "Forwarding an onion message to peer {}", next_node_id);
975 log_trace!(self.logger, "Dropping forwarded onion message to disconnected peer {:?}", next_node_id);
981 log_error!(self.logger, "Failed to process onion message {:?}", e);
986 fn peer_connected(&self, their_node_id: &PublicKey, init: &msgs::Init, _inbound: bool) -> Result<(), ()> {
987 if init.features.supports_onion_messages() {
988 self.message_recipients.lock().unwrap()
989 .entry(*their_node_id)
990 .or_insert_with(|| OnionMessageRecipient::ConnectedPeer(VecDeque::new()))
993 self.message_recipients.lock().unwrap().remove(their_node_id);
999 fn peer_disconnected(&self, their_node_id: &PublicKey) {
1000 match self.message_recipients.lock().unwrap().remove(their_node_id) {
1001 Some(OnionMessageRecipient::ConnectedPeer(..)) => {},
1002 Some(_) => debug_assert!(false),
1007 fn timer_tick_occurred(&self) {
1008 let mut message_recipients = self.message_recipients.lock().unwrap();
1010 // Drop any pending recipients since the last call to avoid retaining buffered messages for
1012 message_recipients.retain(|_, recipient| match recipient {
1013 OnionMessageRecipient::PendingConnection(_, None, ticks) => *ticks < MAX_TIMER_TICKS,
1014 OnionMessageRecipient::PendingConnection(_, Some(_), _) => true,
1018 // Increment a timer tick for pending recipients so that their buffered messages are dropped
1019 // at MAX_TIMER_TICKS.
1020 for recipient in message_recipients.values_mut() {
1021 if let OnionMessageRecipient::PendingConnection(_, None, ticks) = recipient {
1027 fn provided_node_features(&self) -> NodeFeatures {
1028 let mut features = NodeFeatures::empty();
1029 features.set_onion_messages_optional();
1033 fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
1034 let mut features = InitFeatures::empty();
1035 features.set_onion_messages_optional();
1039 // Before returning any messages to send for the peer, this method will see if any messages were
1040 // enqueued in the handler by users, find a path to the corresponding blinded path's introduction
1041 // node, and then enqueue the message for sending to the first peer in the full path.
1042 fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<OnionMessage> {
1043 // Enqueue any initiating `OffersMessage`s to send.
1044 for message in self.offers_handler.release_pending_messages() {
1045 #[cfg(not(c_bindings))]
1046 let PendingOnionMessage { contents, destination, reply_path } = message;
1048 let (contents, destination, reply_path) = message;
1049 let _ = self.find_path_and_enqueue_onion_message(
1050 contents, destination, reply_path, format_args!("when sending OffersMessage")
1054 // Enqueue any initiating `CustomMessage`s to send.
1055 for message in self.custom_handler.release_pending_custom_messages() {
1056 #[cfg(not(c_bindings))]
1057 let PendingOnionMessage { contents, destination, reply_path } = message;
1059 let (contents, destination, reply_path) = message;
1060 let _ = self.find_path_and_enqueue_onion_message(
1061 contents, destination, reply_path, format_args!("when sending CustomMessage")
1065 self.message_recipients.lock().unwrap()
1066 .get_mut(&peer_node_id)
1067 .and_then(|buffer| buffer.dequeue_message())
1071 // TODO: parameterize the below Simple* types with OnionMessenger and handle the messages it
1073 /// Useful for simplifying the parameters of [`SimpleArcChannelManager`] and
1074 /// [`SimpleArcPeerManager`]. See their docs for more details.
1076 /// This is not exported to bindings users as type aliases aren't supported in most languages.
1078 /// [`SimpleArcChannelManager`]: crate::ln::channelmanager::SimpleArcChannelManager
1079 /// [`SimpleArcPeerManager`]: crate::ln::peer_handler::SimpleArcPeerManager
1080 #[cfg(not(c_bindings))]
1081 pub type SimpleArcOnionMessenger<M, T, F, L> = OnionMessenger<
1085 Arc<DefaultMessageRouter<Arc<NetworkGraph<Arc<L>>>, Arc<L>, Arc<KeysManager>>>,
1086 Arc<SimpleArcChannelManager<M, T, F, L>>,
1087 IgnoringMessageHandler
1090 /// Useful for simplifying the parameters of [`SimpleRefChannelManager`] and
1091 /// [`SimpleRefPeerManager`]. See their docs for more details.
1093 /// This is not exported to bindings users as type aliases aren't supported in most languages.
1095 /// [`SimpleRefChannelManager`]: crate::ln::channelmanager::SimpleRefChannelManager
1096 /// [`SimpleRefPeerManager`]: crate::ln::peer_handler::SimpleRefPeerManager
1097 #[cfg(not(c_bindings))]
1098 pub type SimpleRefOnionMessenger<
1099 'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, 'i, 'j, M, T, F, L
1104 &'i DefaultMessageRouter<&'g NetworkGraph<&'b L>, &'b L, &'a KeysManager>,
1105 &'j SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, M, T, F, L>,
1106 IgnoringMessageHandler
1109 /// Construct onion packet payloads and keys for sending an onion message along the given
1110 /// `unblinded_path` to the given `destination`.
1111 fn packet_payloads_and_keys<T: OnionMessageContents, S: secp256k1::Signing + secp256k1::Verification>(
1112 secp_ctx: &Secp256k1<S>, unblinded_path: &[PublicKey], destination: Destination, message: T,
1113 mut reply_path: Option<BlindedPath>, session_priv: &SecretKey
1114 ) -> Result<(Vec<(Payload<T>, [u8; 32])>, Vec<onion_utils::OnionKeys>), secp256k1::Error> {
1115 let num_hops = unblinded_path.len() + destination.num_hops();
1116 let mut payloads = Vec::with_capacity(num_hops);
1117 let mut onion_packet_keys = Vec::with_capacity(num_hops);
1119 let (mut intro_node_id_blinding_pt, num_blinded_hops) = if let Destination::BlindedPath(BlindedPath {
1120 introduction_node_id, blinding_point, blinded_hops }) = &destination {
1121 (Some((*introduction_node_id, *blinding_point)), blinded_hops.len()) } else { (None, 0) };
1122 let num_unblinded_hops = num_hops - num_blinded_hops;
1124 let mut unblinded_path_idx = 0;
1125 let mut blinded_path_idx = 0;
1126 let mut prev_control_tlvs_ss = None;
1127 let mut final_control_tlvs = None;
1128 utils::construct_keys_callback(secp_ctx, unblinded_path.iter(), Some(destination), session_priv,
1129 |_, onion_packet_ss, ephemeral_pubkey, control_tlvs_ss, unblinded_pk_opt, enc_payload_opt| {
1130 if num_unblinded_hops != 0 && unblinded_path_idx < num_unblinded_hops {
1131 if let Some(ss) = prev_control_tlvs_ss.take() {
1132 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(
1134 next_node_id: unblinded_pk_opt.unwrap(),
1135 next_blinding_override: None,
1139 prev_control_tlvs_ss = Some(control_tlvs_ss);
1140 unblinded_path_idx += 1;
1141 } else if let Some((intro_node_id, blinding_pt)) = intro_node_id_blinding_pt.take() {
1142 if let Some(control_tlvs_ss) = prev_control_tlvs_ss.take() {
1143 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
1144 next_node_id: intro_node_id,
1145 next_blinding_override: Some(blinding_pt),
1146 })), control_tlvs_ss));
1149 if blinded_path_idx < num_blinded_hops.saturating_sub(1) && enc_payload_opt.is_some() {
1150 payloads.push((Payload::Forward(ForwardControlTlvs::Blinded(enc_payload_opt.unwrap())),
1152 blinded_path_idx += 1;
1153 } else if let Some(encrypted_payload) = enc_payload_opt {
1154 final_control_tlvs = Some(ReceiveControlTlvs::Blinded(encrypted_payload));
1155 prev_control_tlvs_ss = Some(control_tlvs_ss);
1158 let (rho, mu) = onion_utils::gen_rho_mu_from_shared_secret(onion_packet_ss.as_ref());
1159 onion_packet_keys.push(onion_utils::OnionKeys {
1161 shared_secret: onion_packet_ss,
1163 blinding_factor: [0; 32],
1171 if let Some(control_tlvs) = final_control_tlvs {
1172 payloads.push((Payload::Receive {
1174 reply_path: reply_path.take(),
1176 }, prev_control_tlvs_ss.unwrap()));
1178 payloads.push((Payload::Receive {
1179 control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id: None, }),
1180 reply_path: reply_path.take(),
1182 }, prev_control_tlvs_ss.unwrap()));
1185 Ok((payloads, onion_packet_keys))
1188 /// Errors if the serialized payload size exceeds onion_message::BIG_PACKET_HOP_DATA_LEN
1189 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, ()> {
1191 // "`len` allows larger messages to be sent than the standard 1300 bytes allowed for an HTLC
1192 // onion, but this should be used sparingly as it is reduces anonymity set, hence the
1193 // recommendation that it either look like an HTLC onion, or if larger, be a fixed size."
1194 let payloads_ser_len = onion_utils::payloads_serialized_length(&payloads);
1195 let hop_data_len = if payloads_ser_len <= SMALL_PACKET_HOP_DATA_LEN {
1196 SMALL_PACKET_HOP_DATA_LEN
1197 } else if payloads_ser_len <= BIG_PACKET_HOP_DATA_LEN {
1198 BIG_PACKET_HOP_DATA_LEN
1199 } else { return Err(()) };
1201 onion_utils::construct_onion_message_packet::<_, _>(
1202 payloads, onion_keys, prng_seed, hop_data_len)