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, IntroductionNode, NextMessageHop, NodeIdLookUp};
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 use crate::ln::features::{InitFeatures, NodeFeatures};
24 use crate::ln::msgs::{self, OnionMessage, OnionMessageHandler, SocketAddress};
25 use crate::ln::onion_utils;
26 use crate::routing::gossip::{NetworkGraph, NodeId, ReadOnlyNetworkGraph};
27 use super::packet::OnionMessageContents;
28 use super::packet::ParsedOnionMessageContents;
29 use super::offers::OffersMessageHandler;
30 use super::packet::{BIG_PACKET_HOP_DATA_LEN, ForwardControlTlvs, Packet, Payload, ReceiveControlTlvs, SMALL_PACKET_HOP_DATA_LEN};
31 use crate::util::logger::{Logger, WithContext};
32 use crate::util::ser::Writeable;
37 use crate::sync::Mutex;
38 use crate::prelude::*;
40 #[cfg(not(c_bindings))]
42 crate::sign::KeysManager,
43 crate::ln::channelmanager::{SimpleArcChannelManager, SimpleRefChannelManager},
44 crate::ln::peer_handler::IgnoringMessageHandler,
48 pub(super) const MAX_TIMER_TICKS: usize = 2;
50 /// A sender, receiver and forwarder of [`OnionMessage`]s.
52 /// # Handling Messages
54 /// `OnionMessenger` implements [`OnionMessageHandler`], making it responsible for either forwarding
55 /// messages to peers or delegating to the appropriate handler for the message type. Currently, the
56 /// available handlers are:
57 /// * [`OffersMessageHandler`], for responding to [`InvoiceRequest`]s and paying [`Bolt12Invoice`]s
58 /// * [`CustomOnionMessageHandler`], for handling user-defined message types
60 /// # Sending Messages
62 /// [`OnionMessage`]s are sent initially using [`OnionMessenger::send_onion_message`]. When handling
63 /// a message, the matched handler may return a response message which `OnionMessenger` will send
69 /// # extern crate bitcoin;
70 /// # use bitcoin::hashes::_export::_core::time::Duration;
71 /// # use bitcoin::hashes::hex::FromHex;
72 /// # use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey, self};
73 /// # use lightning::blinded_path::{BlindedPath, EmptyNodeIdLookUp};
74 /// # use lightning::sign::{EntropySource, KeysManager};
75 /// # use lightning::ln::peer_handler::IgnoringMessageHandler;
76 /// # use lightning::onion_message::messenger::{Destination, MessageRouter, OnionMessagePath, OnionMessenger};
77 /// # use lightning::onion_message::packet::OnionMessageContents;
78 /// # use lightning::util::logger::{Logger, Record};
79 /// # use lightning::util::ser::{Writeable, Writer};
80 /// # use lightning::io;
81 /// # use std::sync::Arc;
82 /// # struct FakeLogger;
83 /// # impl Logger for FakeLogger {
84 /// # fn log(&self, record: Record) { println!("{:?}" , record); }
86 /// # struct FakeMessageRouter {}
87 /// # impl MessageRouter for FakeMessageRouter {
88 /// # fn find_path(&self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination) -> Result<OnionMessagePath, ()> {
89 /// # let secp_ctx = Secp256k1::new();
90 /// # let node_secret = SecretKey::from_slice(&<Vec<u8>>::from_hex("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
91 /// # let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
92 /// # let hop_node_id2 = hop_node_id1;
93 /// # Ok(OnionMessagePath {
94 /// # intermediate_nodes: vec![hop_node_id1, hop_node_id2],
96 /// # first_node_addresses: None,
99 /// # fn create_blinded_paths<T: secp256k1::Signing + secp256k1::Verification>(
100 /// # &self, _recipient: PublicKey, _peers: Vec<PublicKey>, _secp_ctx: &Secp256k1<T>
101 /// # ) -> Result<Vec<BlindedPath>, ()> {
105 /// # let seed = [42u8; 32];
106 /// # let time = Duration::from_secs(123456);
107 /// # let keys_manager = KeysManager::new(&seed, time.as_secs(), time.subsec_nanos());
108 /// # let logger = Arc::new(FakeLogger {});
109 /// # let node_secret = SecretKey::from_slice(&<Vec<u8>>::from_hex("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
110 /// # let secp_ctx = Secp256k1::new();
111 /// # let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
112 /// # let (hop_node_id3, hop_node_id4) = (hop_node_id1, hop_node_id1);
113 /// # let destination_node_id = hop_node_id1;
114 /// # let node_id_lookup = EmptyNodeIdLookUp {};
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, &node_id_lookup, message_router,
122 /// &offers_message_handler, &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
138 /// fn msg_type(&self) -> &'static str { "YourCustomMessageType" }
140 /// // Send a custom onion message to a node id.
141 /// let destination = Destination::Node(destination_node_id);
142 /// let reply_path = None;
143 /// # let message = YourCustomMessage {};
144 /// onion_messenger.send_onion_message(message, destination, reply_path);
146 /// // Create a blinded path to yourself, for someone to send an onion message to.
147 /// # let your_node_id = hop_node_id1;
148 /// let hops = [hop_node_id3, hop_node_id4, your_node_id];
149 /// let blinded_path = BlindedPath::new_for_message(&hops, &keys_manager, &secp_ctx).unwrap();
151 /// // Send a custom onion message to a blinded path.
152 /// let destination = Destination::BlindedPath(blinded_path);
153 /// let reply_path = None;
154 /// # let message = YourCustomMessage {};
155 /// onion_messenger.send_onion_message(message, destination, reply_path);
158 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
159 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
160 pub struct OnionMessenger<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, CMH: Deref>
162 ES::Target: EntropySource,
163 NS::Target: NodeSigner,
165 NL::Target: NodeIdLookUp,
166 MR::Target: MessageRouter,
167 OMH::Target: OffersMessageHandler,
168 CMH::Target: CustomOnionMessageHandler,
173 message_recipients: Mutex<HashMap<PublicKey, OnionMessageRecipient>>,
174 secp_ctx: Secp256k1<secp256k1::All>,
179 intercept_messages_for_offline_peers: bool,
180 pending_events: Mutex<Vec<Event>>,
183 /// [`OnionMessage`]s buffered to be sent.
184 enum OnionMessageRecipient {
185 /// Messages for a node connected as a peer.
186 ConnectedPeer(VecDeque<OnionMessage>),
188 /// Messages for a node that is not yet connected, which are dropped after [`MAX_TIMER_TICKS`]
189 /// and tracked here.
190 PendingConnection(VecDeque<OnionMessage>, Option<Vec<SocketAddress>>, usize),
193 impl OnionMessageRecipient {
194 fn pending_connection(addresses: Vec<SocketAddress>) -> Self {
195 Self::PendingConnection(VecDeque::new(), Some(addresses), 0)
198 fn pending_messages(&self) -> &VecDeque<OnionMessage> {
200 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
201 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
205 fn enqueue_message(&mut self, message: OnionMessage) {
206 let pending_messages = match self {
207 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
208 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
211 pending_messages.push_back(message);
214 fn dequeue_message(&mut self) -> Option<OnionMessage> {
215 let pending_messages = match self {
216 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
217 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => {
218 debug_assert!(false);
223 pending_messages.pop_front()
227 fn release_pending_messages(&mut self) -> VecDeque<OnionMessage> {
228 let pending_messages = match self {
229 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
230 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
233 core::mem::take(pending_messages)
236 fn mark_connected(&mut self) {
237 if let OnionMessageRecipient::PendingConnection(pending_messages, _, _) = self {
238 let mut new_pending_messages = VecDeque::new();
239 core::mem::swap(pending_messages, &mut new_pending_messages);
240 *self = OnionMessageRecipient::ConnectedPeer(new_pending_messages);
244 fn is_connected(&self) -> bool {
246 OnionMessageRecipient::ConnectedPeer(..) => true,
247 OnionMessageRecipient::PendingConnection(..) => false,
253 /// The `Responder` struct creates an appropriate [`ResponseInstruction`]
254 /// for responding to a message.
255 pub struct Responder {
256 /// The path along which a response can be sent.
257 reply_path: BlindedPath,
258 path_id: Option<[u8; 32]>
262 /// Creates a new [`Responder`] instance with the provided reply path.
263 fn new(reply_path: BlindedPath, path_id: Option<[u8; 32]>) -> Self {
270 /// Creates the appropriate [`ResponseInstruction`] for a given response.
271 pub fn respond<T: OnionMessageContents>(self, response: T) -> ResponseInstruction<T> {
272 ResponseInstruction::WithoutReplyPath(OnionMessageResponse {
274 reply_path: self.reply_path,
275 path_id: self.path_id,
280 /// This struct contains the information needed to reply to a received message.
281 pub struct OnionMessageResponse<T: OnionMessageContents> {
283 reply_path: BlindedPath,
284 path_id: Option<[u8; 32]>,
287 /// `ResponseInstruction` represents instructions for responding to received messages.
288 pub enum ResponseInstruction<T: OnionMessageContents> {
289 /// Indicates that a response should be sent without including a reply path
290 /// for the recipient to respond back.
291 WithoutReplyPath(OnionMessageResponse<T>),
292 /// Indicates that there's no response to send back.
296 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
298 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
299 /// enqueued for sending.
300 #[cfg(not(c_bindings))]
301 pub struct PendingOnionMessage<T: OnionMessageContents> {
302 /// The message contents to send in an [`OnionMessage`].
305 /// The destination of the message.
306 pub destination: Destination,
308 /// A reply path to include in the [`OnionMessage`] for a response.
309 pub reply_path: Option<BlindedPath>,
313 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
315 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
316 /// enqueued for sending.
317 pub type PendingOnionMessage<T> = (T, Destination, Option<BlindedPath>);
319 pub(crate) fn new_pending_onion_message<T: OnionMessageContents>(
320 contents: T, destination: Destination, reply_path: Option<BlindedPath>
321 ) -> PendingOnionMessage<T> {
322 #[cfg(not(c_bindings))]
323 return PendingOnionMessage { contents, destination, reply_path };
325 return (contents, destination, reply_path);
328 /// A trait defining behavior for routing an [`OnionMessage`].
329 pub trait MessageRouter {
330 /// Returns a route for sending an [`OnionMessage`] to the given [`Destination`].
332 &self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
333 ) -> Result<OnionMessagePath, ()>;
335 /// Creates [`BlindedPath`]s to the `recipient` node. The nodes in `peers` are assumed to be
336 /// direct peers with the `recipient`.
337 fn create_blinded_paths<
338 T: secp256k1::Signing + secp256k1::Verification
340 &self, recipient: PublicKey, peers: Vec<PublicKey>, secp_ctx: &Secp256k1<T>,
341 ) -> Result<Vec<BlindedPath>, ()>;
344 /// A [`MessageRouter`] that can only route to a directly connected [`Destination`].
345 pub struct DefaultMessageRouter<G: Deref<Target=NetworkGraph<L>>, L: Deref, ES: Deref>
348 ES::Target: EntropySource,
354 impl<G: Deref<Target=NetworkGraph<L>>, L: Deref, ES: Deref> DefaultMessageRouter<G, L, ES>
357 ES::Target: EntropySource,
359 /// Creates a [`DefaultMessageRouter`] using the given [`NetworkGraph`].
360 pub fn new(network_graph: G, entropy_source: ES) -> Self {
361 Self { network_graph, entropy_source }
365 impl<G: Deref<Target=NetworkGraph<L>>, L: Deref, ES: Deref> MessageRouter for DefaultMessageRouter<G, L, ES>
368 ES::Target: EntropySource,
371 &self, sender: PublicKey, peers: Vec<PublicKey>, mut destination: Destination
372 ) -> Result<OnionMessagePath, ()> {
373 let network_graph = self.network_graph.deref().read_only();
374 destination.resolve(&network_graph);
376 let first_node = match destination.first_node() {
377 Some(first_node) => first_node,
378 None => return Err(()),
381 if peers.contains(&first_node) || sender == first_node {
382 Ok(OnionMessagePath {
383 intermediate_nodes: vec![], destination, first_node_addresses: None
386 let node_details = network_graph
387 .node(&NodeId::from_pubkey(&first_node))
388 .and_then(|node_info| node_info.announcement_info.as_ref())
389 .map(|announcement_info| (announcement_info.features(), announcement_info.addresses()));
392 Some((features, addresses)) if features.supports_onion_messages() && addresses.len() > 0 => {
393 let first_node_addresses = Some(addresses.clone());
394 Ok(OnionMessagePath {
395 intermediate_nodes: vec![], destination, first_node_addresses
403 fn create_blinded_paths<
404 T: secp256k1::Signing + secp256k1::Verification
406 &self, recipient: PublicKey, peers: Vec<PublicKey>, secp_ctx: &Secp256k1<T>,
407 ) -> Result<Vec<BlindedPath>, ()> {
408 // Limit the number of blinded paths that are computed.
409 const MAX_PATHS: usize = 3;
411 // Ensure peers have at least three channels so that it is more difficult to infer the
412 // recipient's node_id.
413 const MIN_PEER_CHANNELS: usize = 3;
415 let network_graph = self.network_graph.deref().read_only();
416 let is_recipient_announced =
417 network_graph.nodes().contains_key(&NodeId::from_pubkey(&recipient));
419 let mut peer_info = peers.iter()
420 // Limit to peers with announced channels
423 .node(&NodeId::from_pubkey(pubkey))
424 .filter(|info| info.channels.len() >= MIN_PEER_CHANNELS)
425 .map(|info| (*pubkey, info.is_tor_only(), info.channels.len()))
427 // Exclude Tor-only nodes when the recipient is announced.
428 .filter(|(_, is_tor_only, _)| !(*is_tor_only && is_recipient_announced))
429 .collect::<Vec<_>>();
431 // Prefer using non-Tor nodes with the most channels as the introduction node.
432 peer_info.sort_unstable_by(|(_, a_tor_only, a_channels), (_, b_tor_only, b_channels)| {
433 a_tor_only.cmp(b_tor_only).then(a_channels.cmp(b_channels).reverse())
436 let paths = peer_info.into_iter()
437 .map(|(pubkey, _, _)| vec![pubkey, recipient])
438 .map(|node_pks| BlindedPath::new_for_message(&node_pks, &*self.entropy_source, secp_ctx))
440 .collect::<Result<Vec<_>, _>>();
443 Ok(paths) if !paths.is_empty() => Ok(paths),
445 if is_recipient_announced {
446 BlindedPath::one_hop_for_message(recipient, &*self.entropy_source, secp_ctx)
447 .map(|path| vec![path])
456 /// A path for sending an [`OnionMessage`].
458 pub struct OnionMessagePath {
459 /// Nodes on the path between the sender and the destination.
460 pub intermediate_nodes: Vec<PublicKey>,
462 /// The recipient of the message.
463 pub destination: Destination,
465 /// Addresses that may be used to connect to [`OnionMessagePath::first_node`].
467 /// Only needs to be set if a connection to the node is required. [`OnionMessenger`] may use
468 /// this to initiate such a connection.
469 pub first_node_addresses: Option<Vec<SocketAddress>>,
472 impl OnionMessagePath {
473 /// Returns the first node in the path.
474 pub fn first_node(&self) -> Option<PublicKey> {
475 self.intermediate_nodes
478 .or_else(|| self.destination.first_node())
482 /// The destination of an onion message.
483 #[derive(Clone, Hash, Debug, PartialEq, Eq)]
484 pub enum Destination {
485 /// We're sending this onion message to a node.
487 /// We're sending this onion message to a blinded path.
488 BlindedPath(BlindedPath),
492 /// Attempts to resolve the [`IntroductionNode::DirectedShortChannelId`] of a
493 /// [`Destination::BlindedPath`] to a [`IntroductionNode::NodeId`], if applicable, using the
494 /// provided [`ReadOnlyNetworkGraph`].
495 pub fn resolve(&mut self, network_graph: &ReadOnlyNetworkGraph) {
496 if let Destination::BlindedPath(path) = self {
497 if let IntroductionNode::DirectedShortChannelId(..) = path.introduction_node {
498 if let Some(pubkey) = path
499 .public_introduction_node_id(network_graph)
500 .and_then(|node_id| node_id.as_pubkey().ok())
502 path.introduction_node = IntroductionNode::NodeId(pubkey);
508 pub(super) fn num_hops(&self) -> usize {
510 Destination::Node(_) => 1,
511 Destination::BlindedPath(BlindedPath { blinded_hops, .. }) => blinded_hops.len(),
515 fn first_node(&self) -> Option<PublicKey> {
517 Destination::Node(node_id) => Some(*node_id),
518 Destination::BlindedPath(BlindedPath { introduction_node, .. }) => {
519 match introduction_node {
520 IntroductionNode::NodeId(pubkey) => Some(*pubkey),
521 IntroductionNode::DirectedShortChannelId(..) => None,
528 /// Result of successfully [sending an onion message].
530 /// [sending an onion message]: OnionMessenger::send_onion_message
531 #[derive(Clone, Hash, Debug, PartialEq, Eq)]
532 pub enum SendSuccess {
533 /// The message was buffered and will be sent once it is processed by
534 /// [`OnionMessageHandler::next_onion_message_for_peer`].
536 /// The message was buffered and will be sent once the node is connected as a peer and it is
537 /// processed by [`OnionMessageHandler::next_onion_message_for_peer`].
538 BufferedAwaitingConnection(PublicKey),
541 /// Errors that may occur when [sending an onion message].
543 /// [sending an onion message]: OnionMessenger::send_onion_message
544 #[derive(Clone, Hash, Debug, PartialEq, Eq)]
546 /// Errored computing onion message packet keys.
547 Secp256k1(secp256k1::Error),
548 /// Because implementations such as Eclair will drop onion messages where the message packet
549 /// exceeds 32834 bytes, we refuse to send messages where the packet exceeds this size.
551 /// The provided [`Destination`] was an invalid [`BlindedPath`] due to not having any blinded
554 /// The first hop is not a peer and doesn't have a known [`SocketAddress`].
555 InvalidFirstHop(PublicKey),
556 /// A path from the sender to the destination could not be found by the [`MessageRouter`].
558 /// Onion message contents must have a TLV type >= 64.
560 /// Our next-hop peer's buffer was full or our total outbound buffer was full.
562 /// Failed to retrieve our node id from the provided [`NodeSigner`].
564 /// [`NodeSigner`]: crate::sign::NodeSigner
566 /// The provided [`Destination`] has a blinded path with an unresolved introduction node. An
567 /// attempt to resolve it in the [`MessageRouter`] when finding an [`OnionMessagePath`] likely
569 UnresolvedIntroductionNode,
570 /// We attempted to send to a blinded path where we are the introduction node, and failed to
571 /// advance the blinded path to make the second hop the new introduction node. Either
572 /// [`NodeSigner::ecdh`] failed, we failed to tweak the current blinding point to get the
573 /// new blinding point, or we were attempting to send to ourselves.
574 BlindedPathAdvanceFailed,
577 /// Handler for custom onion messages. If you are using [`SimpleArcOnionMessenger`],
578 /// [`SimpleRefOnionMessenger`], or prefer to ignore inbound custom onion messages,
579 /// [`IgnoringMessageHandler`] must be provided to [`OnionMessenger::new`]. Otherwise, a custom
580 /// implementation of this trait must be provided, with [`CustomMessage`] specifying the supported
583 /// See [`OnionMessenger`] for example usage.
585 /// [`IgnoringMessageHandler`]: crate::ln::peer_handler::IgnoringMessageHandler
586 /// [`CustomMessage`]: Self::CustomMessage
587 pub trait CustomOnionMessageHandler {
588 /// The message known to the handler. To support multiple message types, you may want to make this
589 /// an enum with a variant for each supported message.
590 type CustomMessage: OnionMessageContents;
592 /// Called with the custom message that was received, returning a response to send, if any.
594 /// The returned [`Self::CustomMessage`], if any, is enqueued to be sent by [`OnionMessenger`].
595 fn handle_custom_message(&self, message: Self::CustomMessage, responder: Option<Responder>) -> ResponseInstruction<Self::CustomMessage>;
597 /// Read a custom message of type `message_type` from `buffer`, returning `Ok(None)` if the
598 /// message type is unknown.
599 fn read_custom_message<R: io::Read>(&self, message_type: u64, buffer: &mut R) -> Result<Option<Self::CustomMessage>, msgs::DecodeError>;
601 /// Releases any [`Self::CustomMessage`]s that need to be sent.
603 /// Typically, this is used for messages initiating a message flow rather than in response to
604 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
605 #[cfg(not(c_bindings))]
606 fn release_pending_custom_messages(&self) -> Vec<PendingOnionMessage<Self::CustomMessage>>;
608 /// Releases any [`Self::CustomMessage`]s that need to be sent.
610 /// Typically, this is used for messages initiating a message flow rather than in response to
611 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
613 fn release_pending_custom_messages(&self) -> Vec<(Self::CustomMessage, Destination, Option<BlindedPath>)>;
616 /// A processed incoming onion message, containing either a Forward (another onion message)
617 /// or a Receive payload with decrypted contents.
618 #[derive(Clone, Debug)]
619 pub enum PeeledOnion<T: OnionMessageContents> {
620 /// Forwarded onion, with the next node id and a new onion
621 Forward(NextMessageHop, OnionMessage),
622 /// Received onion message, with decrypted contents, path_id, and reply path
623 Receive(ParsedOnionMessageContents<T>, Option<[u8; 32]>, Option<BlindedPath>)
627 /// Creates an [`OnionMessage`] with the given `contents` for sending to the destination of
628 /// `path`, first calling [`Destination::resolve`] on `path.destination` with the given
629 /// [`ReadOnlyNetworkGraph`].
631 /// Returns the node id of the peer to send the message to, the message itself, and any addresses
632 /// needed to connect to the first node.
633 pub fn create_onion_message_resolving_destination<
634 ES: Deref, NS: Deref, NL: Deref, T: OnionMessageContents
636 entropy_source: &ES, node_signer: &NS, node_id_lookup: &NL,
637 network_graph: &ReadOnlyNetworkGraph, secp_ctx: &Secp256k1<secp256k1::All>,
638 mut path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
639 ) -> Result<(PublicKey, OnionMessage, Option<Vec<SocketAddress>>), SendError>
641 ES::Target: EntropySource,
642 NS::Target: NodeSigner,
643 NL::Target: NodeIdLookUp,
645 path.destination.resolve(network_graph);
646 create_onion_message(
647 entropy_source, node_signer, node_id_lookup, secp_ctx, path, contents, reply_path,
651 /// Creates an [`OnionMessage`] with the given `contents` for sending to the destination of
654 /// Returns the node id of the peer to send the message to, the message itself, and any addresses
655 /// needed to connect to the first node.
657 /// Returns [`SendError::UnresolvedIntroductionNode`] if:
658 /// - `destination` contains a blinded path with an [`IntroductionNode::DirectedShortChannelId`],
659 /// - unless it can be resolved by [`NodeIdLookUp::next_node_id`].
660 /// Use [`create_onion_message_resolving_destination`] instead to resolve the introduction node
661 /// first with a [`ReadOnlyNetworkGraph`].
662 pub fn create_onion_message<ES: Deref, NS: Deref, NL: Deref, T: OnionMessageContents>(
663 entropy_source: &ES, node_signer: &NS, node_id_lookup: &NL,
664 secp_ctx: &Secp256k1<secp256k1::All>, path: OnionMessagePath, contents: T,
665 reply_path: Option<BlindedPath>,
666 ) -> Result<(PublicKey, OnionMessage, Option<Vec<SocketAddress>>), SendError>
668 ES::Target: EntropySource,
669 NS::Target: NodeSigner,
670 NL::Target: NodeIdLookUp,
672 let OnionMessagePath { intermediate_nodes, mut destination, first_node_addresses } = path;
673 if let Destination::BlindedPath(BlindedPath { ref blinded_hops, .. }) = destination {
674 if blinded_hops.is_empty() {
675 return Err(SendError::TooFewBlindedHops);
679 if contents.tlv_type() < 64 { return Err(SendError::InvalidMessage) }
681 // If we are sending straight to a blinded path and we are the introduction node, we need to
682 // advance the blinded path by 1 hop so the second hop is the new introduction node.
683 if intermediate_nodes.len() == 0 {
684 if let Destination::BlindedPath(ref mut blinded_path) = destination {
685 let our_node_id = node_signer.get_node_id(Recipient::Node)
686 .map_err(|()| SendError::GetNodeIdFailed)?;
687 let introduction_node_id = match blinded_path.introduction_node {
688 IntroductionNode::NodeId(pubkey) => pubkey,
689 IntroductionNode::DirectedShortChannelId(direction, scid) => {
690 match node_id_lookup.next_node_id(scid) {
691 Some(next_node_id) => *direction.select_pubkey(&our_node_id, &next_node_id),
692 None => return Err(SendError::UnresolvedIntroductionNode),
696 if introduction_node_id == our_node_id {
697 advance_path_by_one(blinded_path, node_signer, node_id_lookup, &secp_ctx)
698 .map_err(|()| SendError::BlindedPathAdvanceFailed)?;
703 let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
704 let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
705 let (first_node_id, blinding_point) = if let Some(first_node_id) = intermediate_nodes.first() {
706 (*first_node_id, PublicKey::from_secret_key(&secp_ctx, &blinding_secret))
709 Destination::Node(pk) => (*pk, PublicKey::from_secret_key(&secp_ctx, &blinding_secret)),
710 Destination::BlindedPath(BlindedPath { introduction_node, blinding_point, .. }) => {
711 match introduction_node {
712 IntroductionNode::NodeId(pubkey) => (*pubkey, *blinding_point),
713 IntroductionNode::DirectedShortChannelId(..) => {
714 return Err(SendError::UnresolvedIntroductionNode);
720 let (packet_payloads, packet_keys) = packet_payloads_and_keys(
721 &secp_ctx, &intermediate_nodes, destination, contents, reply_path, &blinding_secret
724 let prng_seed = entropy_source.get_secure_random_bytes();
725 let onion_routing_packet = construct_onion_message_packet(
726 packet_payloads, packet_keys, prng_seed).map_err(|()| SendError::TooBigPacket)?;
728 let message = OnionMessage { blinding_point, onion_routing_packet };
729 Ok((first_node_id, message, first_node_addresses))
732 /// Decode one layer of an incoming [`OnionMessage`].
734 /// Returns either the next layer of the onion for forwarding or the decrypted content for the
736 pub fn peel_onion_message<NS: Deref, L: Deref, CMH: Deref>(
737 msg: &OnionMessage, secp_ctx: &Secp256k1<secp256k1::All>, node_signer: NS, logger: L,
739 ) -> Result<PeeledOnion<<<CMH>::Target as CustomOnionMessageHandler>::CustomMessage>, ()>
741 NS::Target: NodeSigner,
743 CMH::Target: CustomOnionMessageHandler,
745 let control_tlvs_ss = match node_signer.ecdh(Recipient::Node, &msg.blinding_point, None) {
748 log_error!(logger, "Failed to retrieve node secret: {:?}", e);
752 let onion_decode_ss = {
753 let blinding_factor = {
754 let mut hmac = HmacEngine::<Sha256>::new(b"blinded_node_id");
755 hmac.input(control_tlvs_ss.as_ref());
756 Hmac::from_engine(hmac).to_byte_array()
758 match node_signer.ecdh(Recipient::Node, &msg.onion_routing_packet.public_key,
759 Some(&Scalar::from_be_bytes(blinding_factor).unwrap()))
761 Ok(ss) => ss.secret_bytes(),
763 log_trace!(logger, "Failed to compute onion packet shared secret");
768 match onion_utils::decode_next_untagged_hop(
769 onion_decode_ss, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
770 (control_tlvs_ss, custom_handler.deref(), logger.deref())
772 Ok((Payload::Receive::<ParsedOnionMessageContents<<<CMH as Deref>::Target as CustomOnionMessageHandler>::CustomMessage>> {
773 message, control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id }), reply_path,
775 Ok(PeeledOnion::Receive(message, path_id, reply_path))
777 Ok((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
778 next_hop, next_blinding_override
779 })), Some((next_hop_hmac, new_packet_bytes)))) => {
780 // TODO: we need to check whether `next_hop` is our node, in which case this is a dummy
781 // blinded hop and this onion message is destined for us. In this situation, we should keep
782 // unwrapping the onion layers to get to the final payload. Since we don't have the option
783 // of creating blinded paths with dummy hops currently, we should be ok to not handle this
785 let new_pubkey = match onion_utils::next_hop_pubkey(&secp_ctx, msg.onion_routing_packet.public_key, &onion_decode_ss) {
788 log_trace!(logger, "Failed to compute next hop packet pubkey: {}", e);
792 let outgoing_packet = Packet {
794 public_key: new_pubkey,
795 hop_data: new_packet_bytes,
798 let onion_message = OnionMessage {
799 blinding_point: match next_blinding_override {
800 Some(blinding_point) => blinding_point,
802 match onion_utils::next_hop_pubkey(
803 &secp_ctx, msg.blinding_point, control_tlvs_ss.as_ref()
807 log_trace!(logger, "Failed to compute next blinding point: {}", e);
813 onion_routing_packet: outgoing_packet,
816 Ok(PeeledOnion::Forward(next_hop, onion_message))
819 log_trace!(logger, "Errored decoding onion message packet: {:?}", e);
823 log_trace!(logger, "Received bogus onion message packet, either the sender encoded a final hop as a forwarding hop or vice versa");
829 impl<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, CMH: Deref>
830 OnionMessenger<ES, NS, L, NL, MR, OMH, CMH>
832 ES::Target: EntropySource,
833 NS::Target: NodeSigner,
835 NL::Target: NodeIdLookUp,
836 MR::Target: MessageRouter,
837 OMH::Target: OffersMessageHandler,
838 CMH::Target: CustomOnionMessageHandler,
840 /// Constructs a new `OnionMessenger` to send, forward, and delegate received onion messages to
841 /// their respective handlers.
843 entropy_source: ES, node_signer: NS, logger: L, node_id_lookup: NL, message_router: MR,
844 offers_handler: OMH, custom_handler: CMH
847 entropy_source, node_signer, logger, node_id_lookup, message_router,
848 offers_handler, custom_handler, false
852 /// Similar to [`Self::new`], but rather than dropping onion messages that are
853 /// intended to be forwarded to offline peers, we will intercept them for
854 /// later forwarding.
856 /// Interception flow:
857 /// 1. If an onion message for an offline peer is received, `OnionMessenger` will
858 /// generate an [`Event::OnionMessageIntercepted`]. Event handlers can
859 /// then choose to persist this onion message for later forwarding, or drop
861 /// 2. When the offline peer later comes back online, `OnionMessenger` will
862 /// generate an [`Event::OnionMessagePeerConnected`]. Event handlers will
863 /// then fetch all previously intercepted onion messages for this peer.
864 /// 3. Once the stored onion messages are fetched, they can finally be
865 /// forwarded to the now-online peer via [`Self::forward_onion_message`].
869 /// LDK will not rate limit how many [`Event::OnionMessageIntercepted`]s
870 /// are generated, so it is the caller's responsibility to limit how many
871 /// onion messages are persisted and only persist onion messages for relevant
873 pub fn new_with_offline_peer_interception(
874 entropy_source: ES, node_signer: NS, logger: L, node_id_lookup: NL,
875 message_router: MR, offers_handler: OMH, custom_handler: CMH
878 entropy_source, node_signer, logger, node_id_lookup, message_router,
879 offers_handler, custom_handler, true
884 entropy_source: ES, node_signer: NS, logger: L, node_id_lookup: NL,
885 message_router: MR, offers_handler: OMH, custom_handler: CMH,
886 intercept_messages_for_offline_peers: bool
888 let mut secp_ctx = Secp256k1::new();
889 secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
893 message_recipients: Mutex::new(new_hash_map()),
900 intercept_messages_for_offline_peers,
901 pending_events: Mutex::new(Vec::new()),
906 pub(crate) fn set_offers_handler(&mut self, offers_handler: OMH) {
907 self.offers_handler = offers_handler;
910 /// Sends an [`OnionMessage`] with the given `contents` to `destination`.
912 /// See [`OnionMessenger`] for example usage.
913 pub fn send_onion_message<T: OnionMessageContents>(
914 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>
915 ) -> Result<SendSuccess, SendError> {
916 self.find_path_and_enqueue_onion_message(
917 contents, destination, reply_path, format_args!("")
921 fn find_path_and_enqueue_onion_message<T: OnionMessageContents>(
922 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>,
923 log_suffix: fmt::Arguments
924 ) -> Result<SendSuccess, SendError> {
925 let mut logger = WithContext::from(&self.logger, None, None, None);
926 let result = self.find_path(destination).and_then(|path| {
927 let first_hop = path.intermediate_nodes.get(0).map(|p| *p);
928 logger = WithContext::from(&self.logger, first_hop, None, None);
929 self.enqueue_onion_message(path, contents, reply_path, log_suffix)
932 match result.as_ref() {
933 Err(SendError::GetNodeIdFailed) => {
934 log_warn!(logger, "Unable to retrieve node id {}", log_suffix);
936 Err(SendError::PathNotFound) => {
937 log_trace!(logger, "Failed to find path {}", log_suffix);
940 log_trace!(logger, "Failed sending onion message {}: {:?}", log_suffix, e);
942 Ok(SendSuccess::Buffered) => {
943 log_trace!(logger, "Buffered onion message {}", log_suffix);
945 Ok(SendSuccess::BufferedAwaitingConnection(node_id)) => {
948 "Buffered onion message waiting on peer connection {}: {}",
957 fn find_path(&self, destination: Destination) -> Result<OnionMessagePath, SendError> {
958 let sender = self.node_signer
959 .get_node_id(Recipient::Node)
960 .map_err(|_| SendError::GetNodeIdFailed)?;
962 let peers = self.message_recipients.lock().unwrap()
964 .filter(|(_, recipient)| matches!(recipient, OnionMessageRecipient::ConnectedPeer(_)))
965 .map(|(node_id, _)| *node_id)
969 .find_path(sender, peers, destination)
970 .map_err(|_| SendError::PathNotFound)
973 fn enqueue_onion_message<T: OnionMessageContents>(
974 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
975 log_suffix: fmt::Arguments
976 ) -> Result<SendSuccess, SendError> {
977 log_trace!(self.logger, "Constructing onion message {}: {:?}", log_suffix, contents);
979 let (first_node_id, onion_message, addresses) = create_onion_message(
980 &self.entropy_source, &self.node_signer, &self.node_id_lookup, &self.secp_ctx, path,
981 contents, reply_path,
984 let mut message_recipients = self.message_recipients.lock().unwrap();
985 if outbound_buffer_full(&first_node_id, &message_recipients) {
986 return Err(SendError::BufferFull);
989 match message_recipients.entry(first_node_id) {
990 hash_map::Entry::Vacant(e) => match addresses {
991 None => Err(SendError::InvalidFirstHop(first_node_id)),
993 e.insert(OnionMessageRecipient::pending_connection(addresses))
994 .enqueue_message(onion_message);
995 Ok(SendSuccess::BufferedAwaitingConnection(first_node_id))
998 hash_map::Entry::Occupied(mut e) => {
999 e.get_mut().enqueue_message(onion_message);
1000 if e.get().is_connected() {
1001 Ok(SendSuccess::Buffered)
1003 Ok(SendSuccess::BufferedAwaitingConnection(first_node_id))
1009 /// Forwards an [`OnionMessage`] to `peer_node_id`. Useful if we initialized
1010 /// the [`OnionMessenger`] with [`Self::new_with_offline_peer_interception`]
1011 /// and want to forward a previously intercepted onion message to a peer that
1012 /// has just come online.
1013 pub fn forward_onion_message(
1014 &self, message: OnionMessage, peer_node_id: &PublicKey
1015 ) -> Result<(), SendError> {
1016 let mut message_recipients = self.message_recipients.lock().unwrap();
1017 if outbound_buffer_full(&peer_node_id, &message_recipients) {
1018 return Err(SendError::BufferFull);
1021 match message_recipients.entry(*peer_node_id) {
1022 hash_map::Entry::Occupied(mut e) if e.get().is_connected() => {
1023 e.get_mut().enqueue_message(message);
1026 _ => Err(SendError::InvalidFirstHop(*peer_node_id))
1030 #[cfg(any(test, feature = "_test_utils"))]
1031 pub fn send_onion_message_using_path<T: OnionMessageContents>(
1032 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>
1033 ) -> Result<SendSuccess, SendError> {
1034 self.enqueue_onion_message(path, contents, reply_path, format_args!(""))
1037 pub(crate) fn peel_onion_message(
1038 &self, msg: &OnionMessage
1039 ) -> Result<PeeledOnion<<<CMH>::Target as CustomOnionMessageHandler>::CustomMessage>, ()> {
1041 msg, &self.secp_ctx, &*self.node_signer, &*self.logger, &*self.custom_handler
1045 fn handle_onion_message_response<T: OnionMessageContents>(
1046 &self, response: ResponseInstruction<T>
1048 if let ResponseInstruction::WithoutReplyPath(response) = response {
1049 let message_type = response.message.msg_type();
1050 let _ = self.find_path_and_enqueue_onion_message(
1051 response.message, Destination::BlindedPath(response.reply_path), None,
1053 "when responding with {} to an onion message with path_id {:02x?}",
1062 pub(super) fn release_pending_msgs(&self) -> HashMap<PublicKey, VecDeque<OnionMessage>> {
1063 let mut message_recipients = self.message_recipients.lock().unwrap();
1064 let mut msgs = new_hash_map();
1065 // We don't want to disconnect the peers by removing them entirely from the original map, so we
1066 // release the pending message buffers individually.
1067 for (node_id, recipient) in &mut *message_recipients {
1068 msgs.insert(*node_id, recipient.release_pending_messages());
1073 fn enqueue_event(&self, event: Event) {
1074 const MAX_EVENTS_BUFFER_SIZE: usize = (1 << 10) * 256;
1075 let mut pending_events = self.pending_events.lock().unwrap();
1076 let total_buffered_bytes: usize = pending_events
1078 .map(|ev| ev.serialized_length())
1080 if total_buffered_bytes >= MAX_EVENTS_BUFFER_SIZE {
1081 log_trace!(self.logger, "Dropping event {:?}: buffer full", event);
1084 pending_events.push(event);
1088 fn outbound_buffer_full(peer_node_id: &PublicKey, buffer: &HashMap<PublicKey, OnionMessageRecipient>) -> bool {
1089 const MAX_TOTAL_BUFFER_SIZE: usize = (1 << 20) * 128;
1090 const MAX_PER_PEER_BUFFER_SIZE: usize = (1 << 10) * 256;
1091 let mut total_buffered_bytes = 0;
1092 let mut peer_buffered_bytes = 0;
1093 for (pk, peer_buf) in buffer {
1094 for om in peer_buf.pending_messages() {
1095 let om_len = om.serialized_length();
1096 if pk == peer_node_id {
1097 peer_buffered_bytes += om_len;
1099 total_buffered_bytes += om_len;
1101 if total_buffered_bytes >= MAX_TOTAL_BUFFER_SIZE ||
1102 peer_buffered_bytes >= MAX_PER_PEER_BUFFER_SIZE
1111 impl<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, CMH: Deref> EventsProvider
1112 for OnionMessenger<ES, NS, L, NL, MR, OMH, CMH>
1114 ES::Target: EntropySource,
1115 NS::Target: NodeSigner,
1117 NL::Target: NodeIdLookUp,
1118 MR::Target: MessageRouter,
1119 OMH::Target: OffersMessageHandler,
1120 CMH::Target: CustomOnionMessageHandler,
1122 fn process_pending_events<H: Deref>(&self, handler: H) where H::Target: EventHandler {
1123 for (node_id, recipient) in self.message_recipients.lock().unwrap().iter_mut() {
1124 if let OnionMessageRecipient::PendingConnection(_, addresses, _) = recipient {
1125 if let Some(addresses) = addresses.take() {
1126 handler.handle_event(Event::ConnectionNeeded { node_id: *node_id, addresses });
1130 let mut events = Vec::new();
1131 core::mem::swap(&mut *self.pending_events.lock().unwrap(), &mut events);
1133 handler.handle_event(ev);
1138 impl<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, CMH: Deref> OnionMessageHandler
1139 for OnionMessenger<ES, NS, L, NL, MR, OMH, CMH>
1141 ES::Target: EntropySource,
1142 NS::Target: NodeSigner,
1144 NL::Target: NodeIdLookUp,
1145 MR::Target: MessageRouter,
1146 OMH::Target: OffersMessageHandler,
1147 CMH::Target: CustomOnionMessageHandler,
1149 fn handle_onion_message(&self, peer_node_id: &PublicKey, msg: &OnionMessage) {
1150 let logger = WithContext::from(&self.logger, Some(*peer_node_id), None, None);
1151 match self.peel_onion_message(msg) {
1152 Ok(PeeledOnion::Receive(message, path_id, reply_path)) => {
1155 "Received an onion message with path_id {:02x?} and {} reply_path: {:?}",
1156 path_id, if reply_path.is_some() { "a" } else { "no" }, message);
1159 ParsedOnionMessageContents::Offers(msg) => {
1160 let responder = reply_path.map(
1161 |reply_path| Responder::new(reply_path, path_id)
1163 let response_instructions = self.offers_handler.handle_message(msg, responder);
1164 self.handle_onion_message_response(response_instructions);
1166 ParsedOnionMessageContents::Custom(msg) => {
1167 let responder = reply_path.map(
1168 |reply_path| Responder::new(reply_path, path_id)
1170 let response_instructions = self.custom_handler.handle_custom_message(msg, responder);
1171 self.handle_onion_message_response(response_instructions);
1175 Ok(PeeledOnion::Forward(next_hop, onion_message)) => {
1176 let next_node_id = match next_hop {
1177 NextMessageHop::NodeId(pubkey) => pubkey,
1178 NextMessageHop::ShortChannelId(scid) => match self.node_id_lookup.next_node_id(scid) {
1179 Some(pubkey) => pubkey,
1181 log_trace!(self.logger, "Dropping forwarded onion messager: unable to resolve next hop using SCID {}", scid);
1187 let mut message_recipients = self.message_recipients.lock().unwrap();
1188 if outbound_buffer_full(&next_node_id, &message_recipients) {
1191 "Dropping forwarded onion message to peer {}: outbound buffer full",
1198 .entry(next_node_id)
1199 .or_insert_with(|| OnionMessageRecipient::ConnectedPeer(VecDeque::new()));
1201 match message_recipients.entry(next_node_id) {
1202 hash_map::Entry::Occupied(mut e) if matches!(
1203 e.get(), OnionMessageRecipient::ConnectedPeer(..)
1205 e.get_mut().enqueue_message(onion_message);
1206 log_trace!(logger, "Forwarding an onion message to peer {}", next_node_id);
1208 _ if self.intercept_messages_for_offline_peers => {
1210 Event::OnionMessageIntercepted {
1211 peer_node_id: next_node_id, message: onion_message
1218 "Dropping forwarded onion message to disconnected peer {}",
1225 log_error!(logger, "Failed to process onion message {:?}", e);
1230 fn peer_connected(&self, their_node_id: &PublicKey, init: &msgs::Init, _inbound: bool) -> Result<(), ()> {
1231 if init.features.supports_onion_messages() {
1232 self.message_recipients.lock().unwrap()
1233 .entry(*their_node_id)
1234 .or_insert_with(|| OnionMessageRecipient::ConnectedPeer(VecDeque::new()))
1236 if self.intercept_messages_for_offline_peers {
1238 Event::OnionMessagePeerConnected { peer_node_id: *their_node_id }
1242 self.message_recipients.lock().unwrap().remove(their_node_id);
1248 fn peer_disconnected(&self, their_node_id: &PublicKey) {
1249 match self.message_recipients.lock().unwrap().remove(their_node_id) {
1250 Some(OnionMessageRecipient::ConnectedPeer(..)) => {},
1251 Some(_) => debug_assert!(false),
1256 fn timer_tick_occurred(&self) {
1257 let mut message_recipients = self.message_recipients.lock().unwrap();
1259 // Drop any pending recipients since the last call to avoid retaining buffered messages for
1261 message_recipients.retain(|_, recipient| match recipient {
1262 OnionMessageRecipient::PendingConnection(_, None, ticks) => *ticks < MAX_TIMER_TICKS,
1263 OnionMessageRecipient::PendingConnection(_, Some(_), _) => true,
1267 // Increment a timer tick for pending recipients so that their buffered messages are dropped
1268 // at MAX_TIMER_TICKS.
1269 for recipient in message_recipients.values_mut() {
1270 if let OnionMessageRecipient::PendingConnection(_, None, ticks) = recipient {
1276 fn provided_node_features(&self) -> NodeFeatures {
1277 let mut features = NodeFeatures::empty();
1278 features.set_onion_messages_optional();
1282 fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
1283 let mut features = InitFeatures::empty();
1284 features.set_onion_messages_optional();
1288 // Before returning any messages to send for the peer, this method will see if any messages were
1289 // enqueued in the handler by users, find a path to the corresponding blinded path's introduction
1290 // node, and then enqueue the message for sending to the first peer in the full path.
1291 fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<OnionMessage> {
1292 // Enqueue any initiating `OffersMessage`s to send.
1293 for message in self.offers_handler.release_pending_messages() {
1294 #[cfg(not(c_bindings))]
1295 let PendingOnionMessage { contents, destination, reply_path } = message;
1297 let (contents, destination, reply_path) = message;
1298 let _ = self.find_path_and_enqueue_onion_message(
1299 contents, destination, reply_path, format_args!("when sending OffersMessage")
1303 // Enqueue any initiating `CustomMessage`s to send.
1304 for message in self.custom_handler.release_pending_custom_messages() {
1305 #[cfg(not(c_bindings))]
1306 let PendingOnionMessage { contents, destination, reply_path } = message;
1308 let (contents, destination, reply_path) = message;
1309 let _ = self.find_path_and_enqueue_onion_message(
1310 contents, destination, reply_path, format_args!("when sending CustomMessage")
1314 self.message_recipients.lock().unwrap()
1315 .get_mut(&peer_node_id)
1316 .and_then(|buffer| buffer.dequeue_message())
1320 // TODO: parameterize the below Simple* types with OnionMessenger and handle the messages it
1322 /// Useful for simplifying the parameters of [`SimpleArcChannelManager`] and
1323 /// [`SimpleArcPeerManager`]. See their docs for more details.
1325 /// This is not exported to bindings users as type aliases aren't supported in most languages.
1327 /// [`SimpleArcChannelManager`]: crate::ln::channelmanager::SimpleArcChannelManager
1328 /// [`SimpleArcPeerManager`]: crate::ln::peer_handler::SimpleArcPeerManager
1329 #[cfg(not(c_bindings))]
1330 pub type SimpleArcOnionMessenger<M, T, F, L> = OnionMessenger<
1334 Arc<SimpleArcChannelManager<M, T, F, L>>,
1335 Arc<DefaultMessageRouter<Arc<NetworkGraph<Arc<L>>>, Arc<L>, Arc<KeysManager>>>,
1336 Arc<SimpleArcChannelManager<M, T, F, L>>,
1337 IgnoringMessageHandler
1340 /// Useful for simplifying the parameters of [`SimpleRefChannelManager`] and
1341 /// [`SimpleRefPeerManager`]. See their docs for more details.
1343 /// This is not exported to bindings users as type aliases aren't supported in most languages.
1345 /// [`SimpleRefChannelManager`]: crate::ln::channelmanager::SimpleRefChannelManager
1346 /// [`SimpleRefPeerManager`]: crate::ln::peer_handler::SimpleRefPeerManager
1347 #[cfg(not(c_bindings))]
1348 pub type SimpleRefOnionMessenger<
1349 'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, 'i, 'j, M, T, F, L
1354 &'i SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, M, T, F, L>,
1355 &'j DefaultMessageRouter<&'g NetworkGraph<&'b L>, &'b L, &'a KeysManager>,
1356 &'i SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, M, T, F, L>,
1357 IgnoringMessageHandler
1360 /// Construct onion packet payloads and keys for sending an onion message along the given
1361 /// `unblinded_path` to the given `destination`.
1362 fn packet_payloads_and_keys<T: OnionMessageContents, S: secp256k1::Signing + secp256k1::Verification>(
1363 secp_ctx: &Secp256k1<S>, unblinded_path: &[PublicKey], destination: Destination, message: T,
1364 mut reply_path: Option<BlindedPath>, session_priv: &SecretKey
1365 ) -> Result<(Vec<(Payload<T>, [u8; 32])>, Vec<onion_utils::OnionKeys>), SendError> {
1366 let num_hops = unblinded_path.len() + destination.num_hops();
1367 let mut payloads = Vec::with_capacity(num_hops);
1368 let mut onion_packet_keys = Vec::with_capacity(num_hops);
1370 let (mut intro_node_id_blinding_pt, num_blinded_hops) = match &destination {
1371 Destination::Node(_) => (None, 0),
1372 Destination::BlindedPath(BlindedPath { introduction_node, blinding_point, blinded_hops }) => {
1373 let introduction_node_id = match introduction_node {
1374 IntroductionNode::NodeId(pubkey) => pubkey,
1375 IntroductionNode::DirectedShortChannelId(..) => {
1376 return Err(SendError::UnresolvedIntroductionNode);
1379 (Some((*introduction_node_id, *blinding_point)), blinded_hops.len())
1382 let num_unblinded_hops = num_hops - num_blinded_hops;
1384 let mut unblinded_path_idx = 0;
1385 let mut blinded_path_idx = 0;
1386 let mut prev_control_tlvs_ss = None;
1387 let mut final_control_tlvs = None;
1388 utils::construct_keys_callback(secp_ctx, unblinded_path.iter(), Some(destination), session_priv,
1389 |_, onion_packet_ss, ephemeral_pubkey, control_tlvs_ss, unblinded_pk_opt, enc_payload_opt| {
1390 if num_unblinded_hops != 0 && unblinded_path_idx < num_unblinded_hops {
1391 if let Some(ss) = prev_control_tlvs_ss.take() {
1392 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(
1394 next_hop: NextMessageHop::NodeId(unblinded_pk_opt.unwrap()),
1395 next_blinding_override: None,
1399 prev_control_tlvs_ss = Some(control_tlvs_ss);
1400 unblinded_path_idx += 1;
1401 } else if let Some((intro_node_id, blinding_pt)) = intro_node_id_blinding_pt.take() {
1402 if let Some(control_tlvs_ss) = prev_control_tlvs_ss.take() {
1403 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
1404 next_hop: NextMessageHop::NodeId(intro_node_id),
1405 next_blinding_override: Some(blinding_pt),
1406 })), control_tlvs_ss));
1409 if blinded_path_idx < num_blinded_hops.saturating_sub(1) && enc_payload_opt.is_some() {
1410 payloads.push((Payload::Forward(ForwardControlTlvs::Blinded(enc_payload_opt.unwrap())),
1412 blinded_path_idx += 1;
1413 } else if let Some(encrypted_payload) = enc_payload_opt {
1414 final_control_tlvs = Some(ReceiveControlTlvs::Blinded(encrypted_payload));
1415 prev_control_tlvs_ss = Some(control_tlvs_ss);
1418 let (rho, mu) = onion_utils::gen_rho_mu_from_shared_secret(onion_packet_ss.as_ref());
1419 onion_packet_keys.push(onion_utils::OnionKeys {
1421 shared_secret: onion_packet_ss,
1423 blinding_factor: [0; 32],
1429 ).map_err(|e| SendError::Secp256k1(e))?;
1431 if let Some(control_tlvs) = final_control_tlvs {
1432 payloads.push((Payload::Receive {
1434 reply_path: reply_path.take(),
1436 }, prev_control_tlvs_ss.unwrap()));
1438 payloads.push((Payload::Receive {
1439 control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id: None, }),
1440 reply_path: reply_path.take(),
1442 }, prev_control_tlvs_ss.unwrap()));
1445 Ok((payloads, onion_packet_keys))
1448 /// Errors if the serialized payload size exceeds onion_message::BIG_PACKET_HOP_DATA_LEN
1449 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, ()> {
1451 // "`len` allows larger messages to be sent than the standard 1300 bytes allowed for an HTLC
1452 // onion, but this should be used sparingly as it is reduces anonymity set, hence the
1453 // recommendation that it either look like an HTLC onion, or if larger, be a fixed size."
1454 let payloads_ser_len = onion_utils::payloads_serialized_length(&payloads);
1455 let hop_data_len = if payloads_ser_len <= SMALL_PACKET_HOP_DATA_LEN {
1456 SMALL_PACKET_HOP_DATA_LEN
1457 } else if payloads_ser_len <= BIG_PACKET_HOP_DATA_LEN {
1458 BIG_PACKET_HOP_DATA_LEN
1459 } else { return Err(()) };
1461 onion_utils::construct_onion_message_packet::<_, _>(
1462 payloads, onion_keys, prng_seed, hop_data_len)