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, ForwardNode, 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::async_payments::AsyncPaymentsMessageHandler;
28 #[cfg(async_payments)]
29 use super::async_payments::AsyncPaymentsMessage;
30 use super::packet::OnionMessageContents;
31 use super::packet::ParsedOnionMessageContents;
32 use super::offers::OffersMessageHandler;
33 use super::packet::{BIG_PACKET_HOP_DATA_LEN, ForwardControlTlvs, Packet, Payload, ReceiveControlTlvs, SMALL_PACKET_HOP_DATA_LEN};
34 use crate::util::logger::{Logger, WithContext};
35 use crate::util::ser::Writeable;
40 use crate::sync::Mutex;
41 use crate::prelude::*;
43 #[cfg(not(c_bindings))]
45 crate::sign::KeysManager,
46 crate::ln::channelmanager::{SimpleArcChannelManager, SimpleRefChannelManager},
47 crate::ln::peer_handler::IgnoringMessageHandler,
51 pub(super) const MAX_TIMER_TICKS: usize = 2;
53 /// A trivial trait which describes any [`OnionMessenger`].
55 /// This is not exported to bindings users as general cover traits aren't useful in other
57 pub trait AOnionMessenger {
58 /// A type implementing [`EntropySource`]
59 type EntropySource: EntropySource + ?Sized;
60 /// A type that may be dereferenced to [`Self::EntropySource`]
61 type ES: Deref<Target = Self::EntropySource>;
62 /// A type implementing [`NodeSigner`]
63 type NodeSigner: NodeSigner + ?Sized;
64 /// A type that may be dereferenced to [`Self::NodeSigner`]
65 type NS: Deref<Target = Self::NodeSigner>;
66 /// A type implementing [`Logger`]
67 type Logger: Logger + ?Sized;
68 /// A type that may be dereferenced to [`Self::Logger`]
69 type L: Deref<Target = Self::Logger>;
70 /// A type implementing [`NodeIdLookUp`]
71 type NodeIdLookUp: NodeIdLookUp + ?Sized;
72 /// A type that may be dereferenced to [`Self::NodeIdLookUp`]
73 type NL: Deref<Target = Self::NodeIdLookUp>;
74 /// A type implementing [`MessageRouter`]
75 type MessageRouter: MessageRouter + ?Sized;
76 /// A type that may be dereferenced to [`Self::MessageRouter`]
77 type MR: Deref<Target = Self::MessageRouter>;
78 /// A type implementing [`OffersMessageHandler`]
79 type OffersMessageHandler: OffersMessageHandler + ?Sized;
80 /// A type that may be dereferenced to [`Self::OffersMessageHandler`]
81 type OMH: Deref<Target = Self::OffersMessageHandler>;
82 /// A type implementing [`AsyncPaymentsMessageHandler`]
83 type AsyncPaymentsMessageHandler: AsyncPaymentsMessageHandler + ?Sized;
84 /// A type that may be dereferenced to [`Self::AsyncPaymentsMessageHandler`]
85 type APH: Deref<Target = Self::AsyncPaymentsMessageHandler>;
86 /// A type implementing [`CustomOnionMessageHandler`]
87 type CustomOnionMessageHandler: CustomOnionMessageHandler + ?Sized;
88 /// A type that may be dereferenced to [`Self::CustomOnionMessageHandler`]
89 type CMH: Deref<Target = Self::CustomOnionMessageHandler>;
90 /// Returns a reference to the actual [`OnionMessenger`] object.
91 fn get_om(&self) -> &OnionMessenger<Self::ES, Self::NS, Self::L, Self::NL, Self::MR, Self::OMH, Self::APH, Self::CMH>;
94 impl<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, APH: Deref, CMH: Deref> AOnionMessenger
95 for OnionMessenger<ES, NS, L, NL, MR, OMH, APH, CMH> where
96 ES::Target: EntropySource,
97 NS::Target: NodeSigner,
99 NL::Target: NodeIdLookUp,
100 MR::Target: MessageRouter,
101 OMH::Target: OffersMessageHandler,
102 APH:: Target: AsyncPaymentsMessageHandler,
103 CMH::Target: CustomOnionMessageHandler,
105 type EntropySource = ES::Target;
107 type NodeSigner = NS::Target;
109 type Logger = L::Target;
111 type NodeIdLookUp = NL::Target;
113 type MessageRouter = MR::Target;
115 type OffersMessageHandler = OMH::Target;
117 type AsyncPaymentsMessageHandler = APH::Target;
119 type CustomOnionMessageHandler = CMH::Target;
121 fn get_om(&self) -> &OnionMessenger<ES, NS, L, NL, MR, OMH, APH, CMH> { self }
124 /// A sender, receiver and forwarder of [`OnionMessage`]s.
126 /// # Handling Messages
128 /// `OnionMessenger` implements [`OnionMessageHandler`], making it responsible for either forwarding
129 /// messages to peers or delegating to the appropriate handler for the message type. Currently, the
130 /// available handlers are:
131 /// * [`OffersMessageHandler`], for responding to [`InvoiceRequest`]s and paying [`Bolt12Invoice`]s
132 /// * [`CustomOnionMessageHandler`], for handling user-defined message types
134 /// # Sending Messages
136 /// [`OnionMessage`]s are sent initially using [`OnionMessenger::send_onion_message`]. When handling
137 /// a message, the matched handler may return a response message which `OnionMessenger` will send
143 /// # extern crate bitcoin;
144 /// # use bitcoin::hashes::_export::_core::time::Duration;
145 /// # use bitcoin::hashes::hex::FromHex;
146 /// # use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey, self};
147 /// # use lightning::blinded_path::{BlindedPath, EmptyNodeIdLookUp};
148 /// # use lightning::blinded_path::message::ForwardNode;
149 /// # use lightning::sign::{EntropySource, KeysManager};
150 /// # use lightning::ln::peer_handler::IgnoringMessageHandler;
151 /// # use lightning::onion_message::messenger::{Destination, MessageRouter, OnionMessagePath, OnionMessenger};
152 /// # use lightning::onion_message::packet::OnionMessageContents;
153 /// # use lightning::util::logger::{Logger, Record};
154 /// # use lightning::util::ser::{Writeable, Writer};
155 /// # use lightning::io;
156 /// # use std::sync::Arc;
157 /// # struct FakeLogger;
158 /// # impl Logger for FakeLogger {
159 /// # fn log(&self, record: Record) { println!("{:?}" , record); }
161 /// # struct FakeMessageRouter {}
162 /// # impl MessageRouter for FakeMessageRouter {
163 /// # fn find_path(&self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination) -> Result<OnionMessagePath, ()> {
164 /// # let secp_ctx = Secp256k1::new();
165 /// # let node_secret = SecretKey::from_slice(&<Vec<u8>>::from_hex("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
166 /// # let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
167 /// # let hop_node_id2 = hop_node_id1;
168 /// # Ok(OnionMessagePath {
169 /// # intermediate_nodes: vec![hop_node_id1, hop_node_id2],
171 /// # first_node_addresses: None,
174 /// # fn create_blinded_paths<T: secp256k1::Signing + secp256k1::Verification>(
175 /// # &self, _recipient: PublicKey, _peers: Vec<PublicKey>, _secp_ctx: &Secp256k1<T>
176 /// # ) -> Result<Vec<BlindedPath>, ()> {
180 /// # let seed = [42u8; 32];
181 /// # let time = Duration::from_secs(123456);
182 /// # let keys_manager = KeysManager::new(&seed, time.as_secs(), time.subsec_nanos());
183 /// # let logger = Arc::new(FakeLogger {});
184 /// # let node_secret = SecretKey::from_slice(&<Vec<u8>>::from_hex("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
185 /// # let secp_ctx = Secp256k1::new();
186 /// # let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
187 /// # let (hop_node_id3, hop_node_id4) = (hop_node_id1, hop_node_id1);
188 /// # let destination_node_id = hop_node_id1;
189 /// # let node_id_lookup = EmptyNodeIdLookUp {};
190 /// # let message_router = Arc::new(FakeMessageRouter {});
191 /// # let custom_message_handler = IgnoringMessageHandler {};
192 /// # let offers_message_handler = IgnoringMessageHandler {};
193 /// # let async_payments_message_handler = IgnoringMessageHandler {};
194 /// // Create the onion messenger. This must use the same `keys_manager` as is passed to your
195 /// // ChannelManager.
196 /// let onion_messenger = OnionMessenger::new(
197 /// &keys_manager, &keys_manager, logger, &node_id_lookup, message_router,
198 /// &offers_message_handler, &async_payments_message_handler, &custom_message_handler
201 /// # #[derive(Debug)]
202 /// # struct YourCustomMessage {}
203 /// impl Writeable for YourCustomMessage {
204 /// fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
206 /// // Write your custom onion message to `w`
209 /// impl OnionMessageContents for YourCustomMessage {
210 /// fn tlv_type(&self) -> u64 {
211 /// # let your_custom_message_type = 42;
212 /// your_custom_message_type
214 /// fn msg_type(&self) -> &'static str { "YourCustomMessageType" }
216 /// // Send a custom onion message to a node id.
217 /// let destination = Destination::Node(destination_node_id);
218 /// let reply_path = None;
219 /// # let message = YourCustomMessage {};
220 /// onion_messenger.send_onion_message(message, destination, reply_path);
222 /// // Create a blinded path to yourself, for someone to send an onion message to.
223 /// # let your_node_id = hop_node_id1;
225 /// ForwardNode { node_id: hop_node_id3, short_channel_id: None },
226 /// ForwardNode { node_id: hop_node_id4, short_channel_id: None },
228 /// let blinded_path = BlindedPath::new_for_message(&hops, your_node_id, &keys_manager, &secp_ctx).unwrap();
230 /// // Send a custom onion message to a blinded path.
231 /// let destination = Destination::BlindedPath(blinded_path);
232 /// let reply_path = None;
233 /// # let message = YourCustomMessage {};
234 /// onion_messenger.send_onion_message(message, destination, reply_path);
237 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
238 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
239 pub struct OnionMessenger<
240 ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, APH: Deref, CMH: Deref
242 ES::Target: EntropySource,
243 NS::Target: NodeSigner,
245 NL::Target: NodeIdLookUp,
246 MR::Target: MessageRouter,
247 OMH::Target: OffersMessageHandler,
248 APH::Target: AsyncPaymentsMessageHandler,
249 CMH::Target: CustomOnionMessageHandler,
254 message_recipients: Mutex<HashMap<PublicKey, OnionMessageRecipient>>,
255 secp_ctx: Secp256k1<secp256k1::All>,
260 async_payments_handler: APH,
262 intercept_messages_for_offline_peers: bool,
263 pending_events: Mutex<PendingEvents>,
266 struct PendingEvents {
267 intercepted_msgs: Vec<Event>,
268 peer_connecteds: Vec<Event>,
271 /// [`OnionMessage`]s buffered to be sent.
272 enum OnionMessageRecipient {
273 /// Messages for a node connected as a peer.
274 ConnectedPeer(VecDeque<OnionMessage>),
276 /// Messages for a node that is not yet connected, which are dropped after [`MAX_TIMER_TICKS`]
277 /// and tracked here.
278 PendingConnection(VecDeque<OnionMessage>, Option<Vec<SocketAddress>>, usize),
281 impl OnionMessageRecipient {
282 fn pending_connection(addresses: Vec<SocketAddress>) -> Self {
283 Self::PendingConnection(VecDeque::new(), Some(addresses), 0)
286 fn pending_messages(&self) -> &VecDeque<OnionMessage> {
288 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
289 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
293 fn enqueue_message(&mut self, message: OnionMessage) {
294 let pending_messages = match self {
295 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
296 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
299 pending_messages.push_back(message);
302 fn dequeue_message(&mut self) -> Option<OnionMessage> {
303 let pending_messages = match self {
304 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
305 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => {
306 debug_assert!(false);
311 pending_messages.pop_front()
315 fn release_pending_messages(&mut self) -> VecDeque<OnionMessage> {
316 let pending_messages = match self {
317 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
318 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
321 core::mem::take(pending_messages)
324 fn mark_connected(&mut self) {
325 if let OnionMessageRecipient::PendingConnection(pending_messages, _, _) = self {
326 let mut new_pending_messages = VecDeque::new();
327 core::mem::swap(pending_messages, &mut new_pending_messages);
328 *self = OnionMessageRecipient::ConnectedPeer(new_pending_messages);
332 fn is_connected(&self) -> bool {
334 OnionMessageRecipient::ConnectedPeer(..) => true,
335 OnionMessageRecipient::PendingConnection(..) => false,
341 /// The `Responder` struct creates an appropriate [`ResponseInstruction`]
342 /// for responding to a message.
343 #[derive(Clone, Debug, Eq, PartialEq)]
344 pub struct Responder {
345 /// The path along which a response can be sent.
346 reply_path: BlindedPath,
347 path_id: Option<[u8; 32]>
350 impl_writeable_tlv_based!(Responder, {
351 (0, reply_path, required),
352 (2, path_id, option),
356 /// Creates a new [`Responder`] instance with the provided reply path.
357 pub(super) fn new(reply_path: BlindedPath, path_id: Option<[u8; 32]>) -> Self {
364 /// Creates a [`ResponseInstruction::WithoutReplyPath`] for a given response.
366 /// Use when the recipient doesn't need to send back a reply to us.
367 pub fn respond<T: OnionMessageContents>(self, response: T) -> ResponseInstruction<T> {
368 ResponseInstruction::WithoutReplyPath(OnionMessageResponse {
370 reply_path: self.reply_path,
371 path_id: self.path_id,
375 /// Creates a [`ResponseInstruction::WithReplyPath`] for a given response.
377 /// Use when the recipient needs to send back a reply to us.
378 pub fn respond_with_reply_path<T: OnionMessageContents>(self, response: T) -> ResponseInstruction<T> {
379 ResponseInstruction::WithReplyPath(OnionMessageResponse {
381 reply_path: self.reply_path,
382 path_id: self.path_id,
387 /// This struct contains the information needed to reply to a received message.
388 pub struct OnionMessageResponse<T: OnionMessageContents> {
390 reply_path: BlindedPath,
391 path_id: Option<[u8; 32]>,
394 /// `ResponseInstruction` represents instructions for responding to received messages.
395 pub enum ResponseInstruction<T: OnionMessageContents> {
396 /// Indicates that a response should be sent including a reply path for
397 /// the recipient to respond back.
398 WithReplyPath(OnionMessageResponse<T>),
399 /// Indicates that a response should be sent without including a reply path
400 /// for the recipient to respond back.
401 WithoutReplyPath(OnionMessageResponse<T>),
402 /// Indicates that there's no response to send back.
406 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
408 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
409 /// enqueued for sending.
410 #[cfg(not(c_bindings))]
411 pub struct PendingOnionMessage<T: OnionMessageContents> {
412 /// The message contents to send in an [`OnionMessage`].
415 /// The destination of the message.
416 pub destination: Destination,
418 /// A reply path to include in the [`OnionMessage`] for a response.
419 pub reply_path: Option<BlindedPath>,
423 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
425 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
426 /// enqueued for sending.
427 pub type PendingOnionMessage<T> = (T, Destination, Option<BlindedPath>);
429 pub(crate) fn new_pending_onion_message<T: OnionMessageContents>(
430 contents: T, destination: Destination, reply_path: Option<BlindedPath>
431 ) -> PendingOnionMessage<T> {
432 #[cfg(not(c_bindings))]
433 return PendingOnionMessage { contents, destination, reply_path };
435 return (contents, destination, reply_path);
438 /// A trait defining behavior for routing an [`OnionMessage`].
439 pub trait MessageRouter {
440 /// Returns a route for sending an [`OnionMessage`] to the given [`Destination`].
442 &self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
443 ) -> Result<OnionMessagePath, ()>;
445 /// Creates [`BlindedPath`]s to the `recipient` node. The nodes in `peers` are assumed to be
446 /// direct peers with the `recipient`.
447 fn create_blinded_paths<
448 T: secp256k1::Signing + secp256k1::Verification
450 &self, recipient: PublicKey, peers: Vec<PublicKey>, secp_ctx: &Secp256k1<T>,
451 ) -> Result<Vec<BlindedPath>, ()>;
453 /// Creates compact [`BlindedPath`]s to the `recipient` node. The nodes in `peers` are assumed
454 /// to be direct peers with the `recipient`.
456 /// Compact blinded paths use short channel ids instead of pubkeys for a smaller serialization,
457 /// which is beneficial when a QR code is used to transport the data. The SCID is passed using a
458 /// [`ForwardNode`] but may be `None` for graceful degradation.
460 /// Implementations using additional intermediate nodes are responsible for using a
461 /// [`ForwardNode`] with `Some` short channel id, if possible. Similarly, implementations should
462 /// call [`BlindedPath::use_compact_introduction_node`].
464 /// The provided implementation simply delegates to [`MessageRouter::create_blinded_paths`],
465 /// ignoring the short channel ids.
466 fn create_compact_blinded_paths<
467 T: secp256k1::Signing + secp256k1::Verification
469 &self, recipient: PublicKey, peers: Vec<ForwardNode>, secp_ctx: &Secp256k1<T>,
470 ) -> Result<Vec<BlindedPath>, ()> {
473 .map(|ForwardNode { node_id, short_channel_id: _ }| node_id)
475 self.create_blinded_paths(recipient, peers, secp_ctx)
479 /// A [`MessageRouter`] that can only route to a directly connected [`Destination`].
483 /// Creating [`BlindedPath`]s may affect privacy since, if a suitable path cannot be found, it will
484 /// create a one-hop path using the recipient as the introduction node if it is a announced node.
485 /// Otherwise, there is no way to find a path to the introduction node in order to send a message,
486 /// and thus an `Err` is returned.
487 pub struct DefaultMessageRouter<G: Deref<Target=NetworkGraph<L>>, L: Deref, ES: Deref>
490 ES::Target: EntropySource,
496 impl<G: Deref<Target=NetworkGraph<L>>, L: Deref, ES: Deref> DefaultMessageRouter<G, L, ES>
499 ES::Target: EntropySource,
501 /// Creates a [`DefaultMessageRouter`] using the given [`NetworkGraph`].
502 pub fn new(network_graph: G, entropy_source: ES) -> Self {
503 Self { network_graph, entropy_source }
506 fn create_blinded_paths_from_iter<
507 I: ExactSizeIterator<Item = ForwardNode>,
508 T: secp256k1::Signing + secp256k1::Verification
510 &self, recipient: PublicKey, peers: I, secp_ctx: &Secp256k1<T>, compact_paths: bool
511 ) -> Result<Vec<BlindedPath>, ()> {
512 // Limit the number of blinded paths that are computed.
513 const MAX_PATHS: usize = 3;
515 // Ensure peers have at least three channels so that it is more difficult to infer the
516 // recipient's node_id.
517 const MIN_PEER_CHANNELS: usize = 3;
519 let network_graph = self.network_graph.deref().read_only();
520 let is_recipient_announced =
521 network_graph.nodes().contains_key(&NodeId::from_pubkey(&recipient));
523 let has_one_peer = peers.len() == 1;
524 let mut peer_info = peers
525 // Limit to peers with announced channels unless the recipient is unannounced.
528 .node(&NodeId::from_pubkey(&peer.node_id))
530 !is_recipient_announced || info.channels.len() >= MIN_PEER_CHANNELS
532 .map(|info| (peer, info.is_tor_only(), info.channels.len()))
533 // Allow messages directly with the only peer when unannounced.
534 .or_else(|| (!is_recipient_announced && has_one_peer)
535 .then(|| (peer, false, 0))
538 // Exclude Tor-only nodes when the recipient is announced.
539 .filter(|(_, is_tor_only, _)| !(*is_tor_only && is_recipient_announced))
540 .collect::<Vec<_>>();
542 // Prefer using non-Tor nodes with the most channels as the introduction node.
543 peer_info.sort_unstable_by(|(_, a_tor_only, a_channels), (_, b_tor_only, b_channels)| {
544 a_tor_only.cmp(b_tor_only).then(a_channels.cmp(b_channels).reverse())
547 let paths = peer_info.into_iter()
548 .map(|(peer, _, _)| {
549 BlindedPath::new_for_message(&[peer], recipient, &*self.entropy_source, secp_ctx)
552 .collect::<Result<Vec<_>, _>>();
554 let mut paths = match paths {
555 Ok(paths) if !paths.is_empty() => Ok(paths),
557 if is_recipient_announced {
558 BlindedPath::one_hop_for_message(recipient, &*self.entropy_source, secp_ctx)
559 .map(|path| vec![path])
567 for path in &mut paths {
568 path.use_compact_introduction_node(&network_graph);
576 impl<G: Deref<Target=NetworkGraph<L>>, L: Deref, ES: Deref> MessageRouter for DefaultMessageRouter<G, L, ES>
579 ES::Target: EntropySource,
582 &self, sender: PublicKey, peers: Vec<PublicKey>, mut destination: Destination
583 ) -> Result<OnionMessagePath, ()> {
584 let network_graph = self.network_graph.deref().read_only();
585 destination.resolve(&network_graph);
587 let first_node = match destination.first_node() {
588 Some(first_node) => first_node,
589 None => return Err(()),
592 if peers.contains(&first_node) || sender == first_node {
593 Ok(OnionMessagePath {
594 intermediate_nodes: vec![], destination, first_node_addresses: None
597 let node_details = network_graph
598 .node(&NodeId::from_pubkey(&first_node))
599 .and_then(|node_info| node_info.announcement_info.as_ref())
600 .map(|announcement_info| (announcement_info.features(), announcement_info.addresses()));
603 Some((features, addresses)) if features.supports_onion_messages() && addresses.len() > 0 => {
604 let first_node_addresses = Some(addresses.clone());
605 Ok(OnionMessagePath {
606 intermediate_nodes: vec![], destination, first_node_addresses
614 fn create_blinded_paths<
615 T: secp256k1::Signing + secp256k1::Verification
617 &self, recipient: PublicKey, peers: Vec<PublicKey>, secp_ctx: &Secp256k1<T>,
618 ) -> Result<Vec<BlindedPath>, ()> {
621 .map(|node_id| ForwardNode { node_id, short_channel_id: None });
622 self.create_blinded_paths_from_iter(recipient, peers, secp_ctx, false)
625 fn create_compact_blinded_paths<
626 T: secp256k1::Signing + secp256k1::Verification
628 &self, recipient: PublicKey, peers: Vec<ForwardNode>, secp_ctx: &Secp256k1<T>,
629 ) -> Result<Vec<BlindedPath>, ()> {
630 self.create_blinded_paths_from_iter(recipient, peers.into_iter(), secp_ctx, true)
634 /// A path for sending an [`OnionMessage`].
636 pub struct OnionMessagePath {
637 /// Nodes on the path between the sender and the destination.
638 pub intermediate_nodes: Vec<PublicKey>,
640 /// The recipient of the message.
641 pub destination: Destination,
643 /// Addresses that may be used to connect to [`OnionMessagePath::first_node`].
645 /// Only needs to be set if a connection to the node is required. [`OnionMessenger`] may use
646 /// this to initiate such a connection.
647 pub first_node_addresses: Option<Vec<SocketAddress>>,
650 impl OnionMessagePath {
651 /// Returns the first node in the path.
652 pub fn first_node(&self) -> Option<PublicKey> {
653 self.intermediate_nodes
656 .or_else(|| self.destination.first_node())
660 /// The destination of an onion message.
661 #[derive(Clone, Hash, Debug, PartialEq, Eq)]
662 pub enum Destination {
663 /// We're sending this onion message to a node.
665 /// We're sending this onion message to a blinded path.
666 BlindedPath(BlindedPath),
670 /// Attempts to resolve the [`IntroductionNode::DirectedShortChannelId`] of a
671 /// [`Destination::BlindedPath`] to a [`IntroductionNode::NodeId`], if applicable, using the
672 /// provided [`ReadOnlyNetworkGraph`].
673 pub fn resolve(&mut self, network_graph: &ReadOnlyNetworkGraph) {
674 if let Destination::BlindedPath(path) = self {
675 if let IntroductionNode::DirectedShortChannelId(..) = path.introduction_node {
676 if let Some(pubkey) = path
677 .public_introduction_node_id(network_graph)
678 .and_then(|node_id| node_id.as_pubkey().ok())
680 path.introduction_node = IntroductionNode::NodeId(pubkey);
686 pub(super) fn num_hops(&self) -> usize {
688 Destination::Node(_) => 1,
689 Destination::BlindedPath(BlindedPath { blinded_hops, .. }) => blinded_hops.len(),
693 fn first_node(&self) -> Option<PublicKey> {
695 Destination::Node(node_id) => Some(*node_id),
696 Destination::BlindedPath(BlindedPath { introduction_node, .. }) => {
697 match introduction_node {
698 IntroductionNode::NodeId(pubkey) => Some(*pubkey),
699 IntroductionNode::DirectedShortChannelId(..) => None,
706 /// Result of successfully [sending an onion message].
708 /// [sending an onion message]: OnionMessenger::send_onion_message
709 #[derive(Clone, Hash, Debug, PartialEq, Eq)]
710 pub enum SendSuccess {
711 /// The message was buffered and will be sent once it is processed by
712 /// [`OnionMessageHandler::next_onion_message_for_peer`].
714 /// The message was buffered and will be sent once the node is connected as a peer and it is
715 /// processed by [`OnionMessageHandler::next_onion_message_for_peer`].
716 BufferedAwaitingConnection(PublicKey),
719 /// Errors that may occur when [sending an onion message].
721 /// [sending an onion message]: OnionMessenger::send_onion_message
722 #[derive(Clone, Hash, Debug, PartialEq, Eq)]
724 /// Errored computing onion message packet keys.
725 Secp256k1(secp256k1::Error),
726 /// Because implementations such as Eclair will drop onion messages where the message packet
727 /// exceeds 32834 bytes, we refuse to send messages where the packet exceeds this size.
729 /// The provided [`Destination`] was an invalid [`BlindedPath`] due to not having any blinded
732 /// The first hop is not a peer and doesn't have a known [`SocketAddress`].
733 InvalidFirstHop(PublicKey),
734 /// Indicates that a path could not be found by the [`MessageRouter`].
736 /// This occurs when either:
737 /// - No path from the sender to the destination was found to send the onion message
738 /// - No reply path to the sender could be created when responding to an onion message
740 /// Onion message contents must have a TLV type >= 64.
742 /// Our next-hop peer's buffer was full or our total outbound buffer was full.
744 /// Failed to retrieve our node id from the provided [`NodeSigner`].
746 /// [`NodeSigner`]: crate::sign::NodeSigner
748 /// The provided [`Destination`] has a blinded path with an unresolved introduction node. An
749 /// attempt to resolve it in the [`MessageRouter`] when finding an [`OnionMessagePath`] likely
751 UnresolvedIntroductionNode,
752 /// We attempted to send to a blinded path where we are the introduction node, and failed to
753 /// advance the blinded path to make the second hop the new introduction node. Either
754 /// [`NodeSigner::ecdh`] failed, we failed to tweak the current blinding point to get the
755 /// new blinding point, or we were attempting to send to ourselves.
756 BlindedPathAdvanceFailed,
759 /// Handler for custom onion messages. If you are using [`SimpleArcOnionMessenger`],
760 /// [`SimpleRefOnionMessenger`], or prefer to ignore inbound custom onion messages,
761 /// [`IgnoringMessageHandler`] must be provided to [`OnionMessenger::new`]. Otherwise, a custom
762 /// implementation of this trait must be provided, with [`CustomMessage`] specifying the supported
765 /// See [`OnionMessenger`] for example usage.
767 /// [`IgnoringMessageHandler`]: crate::ln::peer_handler::IgnoringMessageHandler
768 /// [`CustomMessage`]: Self::CustomMessage
769 pub trait CustomOnionMessageHandler {
770 /// The message known to the handler. To support multiple message types, you may want to make this
771 /// an enum with a variant for each supported message.
772 type CustomMessage: OnionMessageContents;
774 /// Called with the custom message that was received, returning a response to send, if any.
776 /// The returned [`Self::CustomMessage`], if any, is enqueued to be sent by [`OnionMessenger`].
777 fn handle_custom_message(&self, message: Self::CustomMessage, responder: Option<Responder>) -> ResponseInstruction<Self::CustomMessage>;
779 /// Read a custom message of type `message_type` from `buffer`, returning `Ok(None)` if the
780 /// message type is unknown.
781 fn read_custom_message<R: io::Read>(&self, message_type: u64, buffer: &mut R) -> Result<Option<Self::CustomMessage>, msgs::DecodeError>;
783 /// Releases any [`Self::CustomMessage`]s that need to be sent.
785 /// Typically, this is used for messages initiating a message flow rather than in response to
786 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
787 #[cfg(not(c_bindings))]
788 fn release_pending_custom_messages(&self) -> Vec<PendingOnionMessage<Self::CustomMessage>>;
790 /// Releases any [`Self::CustomMessage`]s that need to be sent.
792 /// Typically, this is used for messages initiating a message flow rather than in response to
793 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
795 fn release_pending_custom_messages(&self) -> Vec<(Self::CustomMessage, Destination, Option<BlindedPath>)>;
798 /// A processed incoming onion message, containing either a Forward (another onion message)
799 /// or a Receive payload with decrypted contents.
800 #[derive(Clone, Debug)]
801 pub enum PeeledOnion<T: OnionMessageContents> {
802 /// Forwarded onion, with the next node id and a new onion
803 Forward(NextMessageHop, OnionMessage),
804 /// Received onion message, with decrypted contents, path_id, and reply path
805 Receive(ParsedOnionMessageContents<T>, Option<[u8; 32]>, Option<BlindedPath>)
809 /// Creates an [`OnionMessage`] with the given `contents` for sending to the destination of
810 /// `path`, first calling [`Destination::resolve`] on `path.destination` with the given
811 /// [`ReadOnlyNetworkGraph`].
813 /// Returns the node id of the peer to send the message to, the message itself, and any addresses
814 /// needed to connect to the first node.
815 pub fn create_onion_message_resolving_destination<
816 ES: Deref, NS: Deref, NL: Deref, T: OnionMessageContents
818 entropy_source: &ES, node_signer: &NS, node_id_lookup: &NL,
819 network_graph: &ReadOnlyNetworkGraph, secp_ctx: &Secp256k1<secp256k1::All>,
820 mut path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
821 ) -> Result<(PublicKey, OnionMessage, Option<Vec<SocketAddress>>), SendError>
823 ES::Target: EntropySource,
824 NS::Target: NodeSigner,
825 NL::Target: NodeIdLookUp,
827 path.destination.resolve(network_graph);
828 create_onion_message(
829 entropy_source, node_signer, node_id_lookup, secp_ctx, path, contents, reply_path,
833 /// Creates an [`OnionMessage`] with the given `contents` for sending to the destination of
836 /// Returns the node id of the peer to send the message to, the message itself, and any addresses
837 /// needed to connect to the first node.
839 /// Returns [`SendError::UnresolvedIntroductionNode`] if:
840 /// - `destination` contains a blinded path with an [`IntroductionNode::DirectedShortChannelId`],
841 /// - unless it can be resolved by [`NodeIdLookUp::next_node_id`].
842 /// Use [`create_onion_message_resolving_destination`] instead to resolve the introduction node
843 /// first with a [`ReadOnlyNetworkGraph`].
844 pub fn create_onion_message<ES: Deref, NS: Deref, NL: Deref, T: OnionMessageContents>(
845 entropy_source: &ES, node_signer: &NS, node_id_lookup: &NL,
846 secp_ctx: &Secp256k1<secp256k1::All>, path: OnionMessagePath, contents: T,
847 reply_path: Option<BlindedPath>,
848 ) -> Result<(PublicKey, OnionMessage, Option<Vec<SocketAddress>>), SendError>
850 ES::Target: EntropySource,
851 NS::Target: NodeSigner,
852 NL::Target: NodeIdLookUp,
854 let OnionMessagePath { intermediate_nodes, mut destination, first_node_addresses } = path;
855 if let Destination::BlindedPath(BlindedPath { ref blinded_hops, .. }) = destination {
856 if blinded_hops.is_empty() {
857 return Err(SendError::TooFewBlindedHops);
861 if contents.tlv_type() < 64 { return Err(SendError::InvalidMessage) }
863 // If we are sending straight to a blinded path and we are the introduction node, we need to
864 // advance the blinded path by 1 hop so the second hop is the new introduction node.
865 if intermediate_nodes.len() == 0 {
866 if let Destination::BlindedPath(ref mut blinded_path) = destination {
867 let our_node_id = node_signer.get_node_id(Recipient::Node)
868 .map_err(|()| SendError::GetNodeIdFailed)?;
869 let introduction_node_id = match blinded_path.introduction_node {
870 IntroductionNode::NodeId(pubkey) => pubkey,
871 IntroductionNode::DirectedShortChannelId(direction, scid) => {
872 match node_id_lookup.next_node_id(scid) {
873 Some(next_node_id) => *direction.select_pubkey(&our_node_id, &next_node_id),
874 None => return Err(SendError::UnresolvedIntroductionNode),
878 if introduction_node_id == our_node_id {
879 advance_path_by_one(blinded_path, node_signer, node_id_lookup, &secp_ctx)
880 .map_err(|()| SendError::BlindedPathAdvanceFailed)?;
885 let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
886 let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
887 let (first_node_id, blinding_point) = if let Some(first_node_id) = intermediate_nodes.first() {
888 (*first_node_id, PublicKey::from_secret_key(&secp_ctx, &blinding_secret))
891 Destination::Node(pk) => (*pk, PublicKey::from_secret_key(&secp_ctx, &blinding_secret)),
892 Destination::BlindedPath(BlindedPath { introduction_node, blinding_point, .. }) => {
893 match introduction_node {
894 IntroductionNode::NodeId(pubkey) => (*pubkey, *blinding_point),
895 IntroductionNode::DirectedShortChannelId(..) => {
896 return Err(SendError::UnresolvedIntroductionNode);
902 let (packet_payloads, packet_keys) = packet_payloads_and_keys(
903 &secp_ctx, &intermediate_nodes, destination, contents, reply_path, &blinding_secret
906 let prng_seed = entropy_source.get_secure_random_bytes();
907 let onion_routing_packet = construct_onion_message_packet(
908 packet_payloads, packet_keys, prng_seed).map_err(|()| SendError::TooBigPacket)?;
910 let message = OnionMessage { blinding_point, onion_routing_packet };
911 Ok((first_node_id, message, first_node_addresses))
914 /// Decode one layer of an incoming [`OnionMessage`].
916 /// Returns either the next layer of the onion for forwarding or the decrypted content for the
918 pub fn peel_onion_message<NS: Deref, L: Deref, CMH: Deref>(
919 msg: &OnionMessage, secp_ctx: &Secp256k1<secp256k1::All>, node_signer: NS, logger: L,
921 ) -> Result<PeeledOnion<<<CMH>::Target as CustomOnionMessageHandler>::CustomMessage>, ()>
923 NS::Target: NodeSigner,
925 CMH::Target: CustomOnionMessageHandler,
927 let control_tlvs_ss = match node_signer.ecdh(Recipient::Node, &msg.blinding_point, None) {
930 log_error!(logger, "Failed to retrieve node secret: {:?}", e);
934 let onion_decode_ss = {
935 let blinding_factor = {
936 let mut hmac = HmacEngine::<Sha256>::new(b"blinded_node_id");
937 hmac.input(control_tlvs_ss.as_ref());
938 Hmac::from_engine(hmac).to_byte_array()
940 match node_signer.ecdh(Recipient::Node, &msg.onion_routing_packet.public_key,
941 Some(&Scalar::from_be_bytes(blinding_factor).unwrap()))
943 Ok(ss) => ss.secret_bytes(),
945 log_trace!(logger, "Failed to compute onion packet shared secret");
950 match onion_utils::decode_next_untagged_hop(
951 onion_decode_ss, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
952 (control_tlvs_ss, custom_handler.deref(), logger.deref())
954 Ok((Payload::Receive::<ParsedOnionMessageContents<<<CMH as Deref>::Target as CustomOnionMessageHandler>::CustomMessage>> {
955 message, control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id }), reply_path,
957 Ok(PeeledOnion::Receive(message, path_id, reply_path))
959 Ok((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
960 next_hop, next_blinding_override
961 })), Some((next_hop_hmac, new_packet_bytes)))) => {
962 // TODO: we need to check whether `next_hop` is our node, in which case this is a dummy
963 // blinded hop and this onion message is destined for us. In this situation, we should keep
964 // unwrapping the onion layers to get to the final payload. Since we don't have the option
965 // of creating blinded paths with dummy hops currently, we should be ok to not handle this
967 let new_pubkey = match onion_utils::next_hop_pubkey(&secp_ctx, msg.onion_routing_packet.public_key, &onion_decode_ss) {
970 log_trace!(logger, "Failed to compute next hop packet pubkey: {}", e);
974 let outgoing_packet = Packet {
976 public_key: new_pubkey,
977 hop_data: new_packet_bytes,
980 let onion_message = OnionMessage {
981 blinding_point: match next_blinding_override {
982 Some(blinding_point) => blinding_point,
984 match onion_utils::next_hop_pubkey(
985 &secp_ctx, msg.blinding_point, control_tlvs_ss.as_ref()
989 log_trace!(logger, "Failed to compute next blinding point: {}", e);
995 onion_routing_packet: outgoing_packet,
998 Ok(PeeledOnion::Forward(next_hop, onion_message))
1001 log_trace!(logger, "Errored decoding onion message packet: {:?}", e);
1005 log_trace!(logger, "Received bogus onion message packet, either the sender encoded a final hop as a forwarding hop or vice versa");
1011 impl<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, APH: Deref, CMH: Deref>
1012 OnionMessenger<ES, NS, L, NL, MR, OMH, APH, CMH>
1014 ES::Target: EntropySource,
1015 NS::Target: NodeSigner,
1017 NL::Target: NodeIdLookUp,
1018 MR::Target: MessageRouter,
1019 OMH::Target: OffersMessageHandler,
1020 APH::Target: AsyncPaymentsMessageHandler,
1021 CMH::Target: CustomOnionMessageHandler,
1023 /// Constructs a new `OnionMessenger` to send, forward, and delegate received onion messages to
1024 /// their respective handlers.
1026 entropy_source: ES, node_signer: NS, logger: L, node_id_lookup: NL, message_router: MR,
1027 offers_handler: OMH, async_payments_handler: APH, custom_handler: CMH
1030 entropy_source, node_signer, logger, node_id_lookup, message_router,
1031 offers_handler, async_payments_handler, custom_handler, false
1035 /// Similar to [`Self::new`], but rather than dropping onion messages that are
1036 /// intended to be forwarded to offline peers, we will intercept them for
1037 /// later forwarding.
1039 /// Interception flow:
1040 /// 1. If an onion message for an offline peer is received, `OnionMessenger` will
1041 /// generate an [`Event::OnionMessageIntercepted`]. Event handlers can
1042 /// then choose to persist this onion message for later forwarding, or drop
1044 /// 2. When the offline peer later comes back online, `OnionMessenger` will
1045 /// generate an [`Event::OnionMessagePeerConnected`]. Event handlers will
1046 /// then fetch all previously intercepted onion messages for this peer.
1047 /// 3. Once the stored onion messages are fetched, they can finally be
1048 /// forwarded to the now-online peer via [`Self::forward_onion_message`].
1052 /// LDK will not rate limit how many [`Event::OnionMessageIntercepted`]s
1053 /// are generated, so it is the caller's responsibility to limit how many
1054 /// onion messages are persisted and only persist onion messages for relevant
1056 pub fn new_with_offline_peer_interception(
1057 entropy_source: ES, node_signer: NS, logger: L, node_id_lookup: NL,
1058 message_router: MR, offers_handler: OMH, async_payments_handler: APH, custom_handler: CMH
1061 entropy_source, node_signer, logger, node_id_lookup, message_router,
1062 offers_handler, async_payments_handler, custom_handler, true
1067 entropy_source: ES, node_signer: NS, logger: L, node_id_lookup: NL,
1068 message_router: MR, offers_handler: OMH, async_payments_handler: APH, custom_handler: CMH,
1069 intercept_messages_for_offline_peers: bool
1071 let mut secp_ctx = Secp256k1::new();
1072 secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
1076 message_recipients: Mutex::new(new_hash_map()),
1082 async_payments_handler,
1084 intercept_messages_for_offline_peers,
1085 pending_events: Mutex::new(PendingEvents {
1086 intercepted_msgs: Vec::new(),
1087 peer_connecteds: Vec::new(),
1093 pub(crate) fn set_offers_handler(&mut self, offers_handler: OMH) {
1094 self.offers_handler = offers_handler;
1097 /// Sends an [`OnionMessage`] with the given `contents` to `destination`.
1099 /// See [`OnionMessenger`] for example usage.
1100 pub fn send_onion_message<T: OnionMessageContents>(
1101 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>
1102 ) -> Result<SendSuccess, SendError> {
1103 self.find_path_and_enqueue_onion_message(
1104 contents, destination, reply_path, format_args!("")
1108 fn find_path_and_enqueue_onion_message<T: OnionMessageContents>(
1109 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>,
1110 log_suffix: fmt::Arguments
1111 ) -> Result<SendSuccess, SendError> {
1112 let mut logger = WithContext::from(&self.logger, None, None, None);
1113 let result = self.find_path(destination).and_then(|path| {
1114 let first_hop = path.intermediate_nodes.get(0).map(|p| *p);
1115 logger = WithContext::from(&self.logger, first_hop, None, None);
1116 self.enqueue_onion_message(path, contents, reply_path, log_suffix)
1119 match result.as_ref() {
1120 Err(SendError::GetNodeIdFailed) => {
1121 log_warn!(logger, "Unable to retrieve node id {}", log_suffix);
1123 Err(SendError::PathNotFound) => {
1124 log_trace!(logger, "Failed to find path {}", log_suffix);
1127 log_trace!(logger, "Failed sending onion message {}: {:?}", log_suffix, e);
1129 Ok(SendSuccess::Buffered) => {
1130 log_trace!(logger, "Buffered onion message {}", log_suffix);
1132 Ok(SendSuccess::BufferedAwaitingConnection(node_id)) => {
1135 "Buffered onion message waiting on peer connection {}: {}",
1144 fn find_path(&self, destination: Destination) -> Result<OnionMessagePath, SendError> {
1145 let sender = self.node_signer
1146 .get_node_id(Recipient::Node)
1147 .map_err(|_| SendError::GetNodeIdFailed)?;
1149 let peers = self.message_recipients.lock().unwrap()
1151 .filter(|(_, recipient)| matches!(recipient, OnionMessageRecipient::ConnectedPeer(_)))
1152 .map(|(node_id, _)| *node_id)
1156 .find_path(sender, peers, destination)
1157 .map_err(|_| SendError::PathNotFound)
1160 fn create_blinded_path(&self) -> Result<BlindedPath, SendError> {
1161 let recipient = self.node_signer
1162 .get_node_id(Recipient::Node)
1163 .map_err(|_| SendError::GetNodeIdFailed)?;
1164 let secp_ctx = &self.secp_ctx;
1166 let peers = self.message_recipients.lock().unwrap()
1168 .filter(|(_, peer)| matches!(peer, OnionMessageRecipient::ConnectedPeer(_)))
1169 .map(|(node_id, _ )| *node_id)
1170 .collect::<Vec<_>>();
1173 .create_blinded_paths(recipient, peers, secp_ctx)
1174 .and_then(|paths| paths.into_iter().next().ok_or(()))
1175 .map_err(|_| SendError::PathNotFound)
1178 fn enqueue_onion_message<T: OnionMessageContents>(
1179 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
1180 log_suffix: fmt::Arguments
1181 ) -> Result<SendSuccess, SendError> {
1182 log_trace!(self.logger, "Constructing onion message {}: {:?}", log_suffix, contents);
1184 let (first_node_id, onion_message, addresses) = create_onion_message(
1185 &self.entropy_source, &self.node_signer, &self.node_id_lookup, &self.secp_ctx, path,
1186 contents, reply_path,
1189 let mut message_recipients = self.message_recipients.lock().unwrap();
1190 if outbound_buffer_full(&first_node_id, &message_recipients) {
1191 return Err(SendError::BufferFull);
1194 match message_recipients.entry(first_node_id) {
1195 hash_map::Entry::Vacant(e) => match addresses {
1196 None => Err(SendError::InvalidFirstHop(first_node_id)),
1197 Some(addresses) => {
1198 e.insert(OnionMessageRecipient::pending_connection(addresses))
1199 .enqueue_message(onion_message);
1200 Ok(SendSuccess::BufferedAwaitingConnection(first_node_id))
1203 hash_map::Entry::Occupied(mut e) => {
1204 e.get_mut().enqueue_message(onion_message);
1205 if e.get().is_connected() {
1206 Ok(SendSuccess::Buffered)
1208 Ok(SendSuccess::BufferedAwaitingConnection(first_node_id))
1214 /// Forwards an [`OnionMessage`] to `peer_node_id`. Useful if we initialized
1215 /// the [`OnionMessenger`] with [`Self::new_with_offline_peer_interception`]
1216 /// and want to forward a previously intercepted onion message to a peer that
1217 /// has just come online.
1218 pub fn forward_onion_message(
1219 &self, message: OnionMessage, peer_node_id: &PublicKey
1220 ) -> Result<(), SendError> {
1221 let mut message_recipients = self.message_recipients.lock().unwrap();
1222 if outbound_buffer_full(&peer_node_id, &message_recipients) {
1223 return Err(SendError::BufferFull);
1226 match message_recipients.entry(*peer_node_id) {
1227 hash_map::Entry::Occupied(mut e) if e.get().is_connected() => {
1228 e.get_mut().enqueue_message(message);
1231 _ => Err(SendError::InvalidFirstHop(*peer_node_id))
1235 #[cfg(any(test, feature = "_test_utils"))]
1236 pub fn send_onion_message_using_path<T: OnionMessageContents>(
1237 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>
1238 ) -> Result<SendSuccess, SendError> {
1239 self.enqueue_onion_message(path, contents, reply_path, format_args!(""))
1242 pub(crate) fn peel_onion_message(
1243 &self, msg: &OnionMessage
1244 ) -> Result<PeeledOnion<<<CMH>::Target as CustomOnionMessageHandler>::CustomMessage>, ()> {
1246 msg, &self.secp_ctx, &*self.node_signer, &*self.logger, &*self.custom_handler
1250 /// Handles the response to an [`OnionMessage`] based on its [`ResponseInstruction`],
1251 /// enqueueing any response for sending.
1253 /// This function is useful for asynchronous handling of [`OnionMessage`]s.
1254 /// Handlers have the option to return [`ResponseInstruction::NoResponse`], indicating that
1255 /// no immediate response should be sent. Then, they can transfer the associated [`Responder`]
1256 /// to another task responsible for generating the response asynchronously. Subsequently, when
1257 /// the response is prepared and ready for sending, that task can invoke this method to enqueue
1258 /// the response for delivery.
1259 pub fn handle_onion_message_response<T: OnionMessageContents>(
1260 &self, response: ResponseInstruction<T>
1261 ) -> Result<Option<SendSuccess>, SendError> {
1262 let (response, create_reply_path) = match response {
1263 ResponseInstruction::WithReplyPath(response) => (response, true),
1264 ResponseInstruction::WithoutReplyPath(response) => (response, false),
1265 ResponseInstruction::NoResponse => return Ok(None),
1268 let message_type = response.message.msg_type();
1269 let reply_path = if create_reply_path {
1270 match self.create_blinded_path() {
1271 Ok(reply_path) => Some(reply_path),
1275 "Failed to create reply path when responding with {} to an onion message \
1276 with path_id {:02x?}: {:?}",
1277 message_type, response.path_id, err
1284 self.find_path_and_enqueue_onion_message(
1285 response.message, Destination::BlindedPath(response.reply_path), reply_path,
1287 "when responding with {} to an onion message with path_id {:02x?}",
1291 ).map(|result| Some(result))
1295 pub(super) fn release_pending_msgs(&self) -> HashMap<PublicKey, VecDeque<OnionMessage>> {
1296 let mut message_recipients = self.message_recipients.lock().unwrap();
1297 let mut msgs = new_hash_map();
1298 // We don't want to disconnect the peers by removing them entirely from the original map, so we
1299 // release the pending message buffers individually.
1300 for (node_id, recipient) in &mut *message_recipients {
1301 msgs.insert(*node_id, recipient.release_pending_messages());
1306 fn enqueue_intercepted_event(&self, event: Event) {
1307 const MAX_EVENTS_BUFFER_SIZE: usize = (1 << 10) * 256;
1308 let mut pending_events = self.pending_events.lock().unwrap();
1309 let total_buffered_bytes: usize =
1310 pending_events.intercepted_msgs.iter().map(|ev| ev.serialized_length()).sum();
1311 if total_buffered_bytes >= MAX_EVENTS_BUFFER_SIZE {
1312 log_trace!(self.logger, "Dropping event {:?}: buffer full", event);
1315 pending_events.intercepted_msgs.push(event);
1318 /// Processes any events asynchronously using the given handler.
1320 /// Note that the event handler is called in the order each event was generated, however
1321 /// futures are polled in parallel for some events to allow for parallelism where events do not
1322 /// have an ordering requirement.
1324 /// See the trait-level documentation of [`EventsProvider`] for requirements.
1325 pub async fn process_pending_events_async<Future: core::future::Future<Output = ()> + core::marker::Unpin, H: Fn(Event) -> Future>(
1328 let mut intercepted_msgs = Vec::new();
1329 let mut peer_connecteds = Vec::new();
1331 let mut pending_events = self.pending_events.lock().unwrap();
1332 core::mem::swap(&mut pending_events.intercepted_msgs, &mut intercepted_msgs);
1333 core::mem::swap(&mut pending_events.peer_connecteds, &mut peer_connecteds);
1336 let mut futures = Vec::with_capacity(intercepted_msgs.len());
1337 for (node_id, recipient) in self.message_recipients.lock().unwrap().iter_mut() {
1338 if let OnionMessageRecipient::PendingConnection(_, addresses, _) = recipient {
1339 if let Some(addresses) = addresses.take() {
1340 futures.push(Some(handler(Event::ConnectionNeeded { node_id: *node_id, addresses })));
1345 for ev in intercepted_msgs {
1346 if let Event::OnionMessageIntercepted { .. } = ev {} else { debug_assert!(false); }
1347 futures.push(Some(handler(ev)));
1349 // Let the `OnionMessageIntercepted` events finish before moving on to peer_connecteds
1350 crate::util::async_poll::MultiFuturePoller(futures).await;
1352 if peer_connecteds.len() <= 1 {
1353 for event in peer_connecteds { handler(event).await; }
1355 let mut futures = Vec::new();
1356 for event in peer_connecteds {
1357 futures.push(Some(handler(event)));
1359 crate::util::async_poll::MultiFuturePoller(futures).await;
1364 fn outbound_buffer_full(peer_node_id: &PublicKey, buffer: &HashMap<PublicKey, OnionMessageRecipient>) -> bool {
1365 const MAX_TOTAL_BUFFER_SIZE: usize = (1 << 20) * 128;
1366 const MAX_PER_PEER_BUFFER_SIZE: usize = (1 << 10) * 256;
1367 let mut total_buffered_bytes = 0;
1368 let mut peer_buffered_bytes = 0;
1369 for (pk, peer_buf) in buffer {
1370 for om in peer_buf.pending_messages() {
1371 let om_len = om.serialized_length();
1372 if pk == peer_node_id {
1373 peer_buffered_bytes += om_len;
1375 total_buffered_bytes += om_len;
1377 if total_buffered_bytes >= MAX_TOTAL_BUFFER_SIZE ||
1378 peer_buffered_bytes >= MAX_PER_PEER_BUFFER_SIZE
1387 impl<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, APH: Deref, CMH: Deref> EventsProvider
1388 for OnionMessenger<ES, NS, L, NL, MR, OMH, APH, CMH>
1390 ES::Target: EntropySource,
1391 NS::Target: NodeSigner,
1393 NL::Target: NodeIdLookUp,
1394 MR::Target: MessageRouter,
1395 OMH::Target: OffersMessageHandler,
1396 APH::Target: AsyncPaymentsMessageHandler,
1397 CMH::Target: CustomOnionMessageHandler,
1399 fn process_pending_events<H: Deref>(&self, handler: H) where H::Target: EventHandler {
1400 for (node_id, recipient) in self.message_recipients.lock().unwrap().iter_mut() {
1401 if let OnionMessageRecipient::PendingConnection(_, addresses, _) = recipient {
1402 if let Some(addresses) = addresses.take() {
1403 handler.handle_event(Event::ConnectionNeeded { node_id: *node_id, addresses });
1407 let mut events = Vec::new();
1409 let mut pending_events = self.pending_events.lock().unwrap();
1410 #[cfg(debug_assertions)] {
1411 for ev in pending_events.intercepted_msgs.iter() {
1412 if let Event::OnionMessageIntercepted { .. } = ev {} else { panic!(); }
1414 for ev in pending_events.peer_connecteds.iter() {
1415 if let Event::OnionMessagePeerConnected { .. } = ev {} else { panic!(); }
1418 core::mem::swap(&mut pending_events.intercepted_msgs, &mut events);
1419 events.append(&mut pending_events.peer_connecteds);
1420 pending_events.peer_connecteds.shrink_to(10); // Limit total heap usage
1423 handler.handle_event(ev);
1428 impl<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, APH: Deref, CMH: Deref> OnionMessageHandler
1429 for OnionMessenger<ES, NS, L, NL, MR, OMH, APH, CMH>
1431 ES::Target: EntropySource,
1432 NS::Target: NodeSigner,
1434 NL::Target: NodeIdLookUp,
1435 MR::Target: MessageRouter,
1436 OMH::Target: OffersMessageHandler,
1437 APH::Target: AsyncPaymentsMessageHandler,
1438 CMH::Target: CustomOnionMessageHandler,
1440 fn handle_onion_message(&self, peer_node_id: &PublicKey, msg: &OnionMessage) {
1441 let logger = WithContext::from(&self.logger, Some(*peer_node_id), None, None);
1442 match self.peel_onion_message(msg) {
1443 Ok(PeeledOnion::Receive(message, path_id, reply_path)) => {
1446 "Received an onion message with path_id {:02x?} and {} reply_path: {:?}",
1447 path_id, if reply_path.is_some() { "a" } else { "no" }, message);
1449 let responder = reply_path.map(
1450 |reply_path| Responder::new(reply_path, path_id)
1453 ParsedOnionMessageContents::Offers(msg) => {
1454 let response_instructions = self.offers_handler.handle_message(msg, responder);
1455 let _ = self.handle_onion_message_response(response_instructions);
1457 #[cfg(async_payments)]
1458 ParsedOnionMessageContents::AsyncPayments(AsyncPaymentsMessage::HeldHtlcAvailable(msg)) => {
1459 let response_instructions = self.async_payments_handler.held_htlc_available(
1462 let _ = self.handle_onion_message_response(response_instructions);
1464 #[cfg(async_payments)]
1465 ParsedOnionMessageContents::AsyncPayments(AsyncPaymentsMessage::ReleaseHeldHtlc(msg)) => {
1466 self.async_payments_handler.release_held_htlc(msg);
1468 ParsedOnionMessageContents::Custom(msg) => {
1469 let response_instructions = self.custom_handler.handle_custom_message(msg, responder);
1470 let _ = self.handle_onion_message_response(response_instructions);
1474 Ok(PeeledOnion::Forward(next_hop, onion_message)) => {
1475 let next_node_id = match next_hop {
1476 NextMessageHop::NodeId(pubkey) => pubkey,
1477 NextMessageHop::ShortChannelId(scid) => match self.node_id_lookup.next_node_id(scid) {
1478 Some(pubkey) => pubkey,
1480 log_trace!(self.logger, "Dropping forwarded onion messager: unable to resolve next hop using SCID {}", scid);
1486 let mut message_recipients = self.message_recipients.lock().unwrap();
1487 if outbound_buffer_full(&next_node_id, &message_recipients) {
1490 "Dropping forwarded onion message to peer {}: outbound buffer full",
1497 .entry(next_node_id)
1498 .or_insert_with(|| OnionMessageRecipient::ConnectedPeer(VecDeque::new()));
1500 match message_recipients.entry(next_node_id) {
1501 hash_map::Entry::Occupied(mut e) if matches!(
1502 e.get(), OnionMessageRecipient::ConnectedPeer(..)
1504 e.get_mut().enqueue_message(onion_message);
1505 log_trace!(logger, "Forwarding an onion message to peer {}", next_node_id);
1507 _ if self.intercept_messages_for_offline_peers => {
1508 self.enqueue_intercepted_event(
1509 Event::OnionMessageIntercepted {
1510 peer_node_id: next_node_id, message: onion_message
1517 "Dropping forwarded onion message to disconnected peer {}",
1524 log_error!(logger, "Failed to process onion message {:?}", e);
1529 fn peer_connected(&self, their_node_id: &PublicKey, init: &msgs::Init, _inbound: bool) -> Result<(), ()> {
1530 if init.features.supports_onion_messages() {
1531 self.message_recipients.lock().unwrap()
1532 .entry(*their_node_id)
1533 .or_insert_with(|| OnionMessageRecipient::ConnectedPeer(VecDeque::new()))
1535 if self.intercept_messages_for_offline_peers {
1536 self.pending_events.lock().unwrap().peer_connecteds.push(
1537 Event::OnionMessagePeerConnected { peer_node_id: *their_node_id }
1541 self.message_recipients.lock().unwrap().remove(their_node_id);
1547 fn peer_disconnected(&self, their_node_id: &PublicKey) {
1548 match self.message_recipients.lock().unwrap().remove(their_node_id) {
1549 Some(OnionMessageRecipient::ConnectedPeer(..)) => {},
1550 Some(_) => debug_assert!(false),
1555 fn timer_tick_occurred(&self) {
1556 let mut message_recipients = self.message_recipients.lock().unwrap();
1558 // Drop any pending recipients since the last call to avoid retaining buffered messages for
1560 message_recipients.retain(|_, recipient| match recipient {
1561 OnionMessageRecipient::PendingConnection(_, None, ticks) => *ticks < MAX_TIMER_TICKS,
1562 OnionMessageRecipient::PendingConnection(_, Some(_), _) => true,
1566 // Increment a timer tick for pending recipients so that their buffered messages are dropped
1567 // at MAX_TIMER_TICKS.
1568 for recipient in message_recipients.values_mut() {
1569 if let OnionMessageRecipient::PendingConnection(_, None, ticks) = recipient {
1575 fn provided_node_features(&self) -> NodeFeatures {
1576 let mut features = NodeFeatures::empty();
1577 features.set_onion_messages_optional();
1581 fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
1582 let mut features = InitFeatures::empty();
1583 features.set_onion_messages_optional();
1587 // Before returning any messages to send for the peer, this method will see if any messages were
1588 // enqueued in the handler by users, find a path to the corresponding blinded path's introduction
1589 // node, and then enqueue the message for sending to the first peer in the full path.
1590 fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<OnionMessage> {
1591 // Enqueue any initiating `OffersMessage`s to send.
1592 for message in self.offers_handler.release_pending_messages() {
1593 #[cfg(not(c_bindings))]
1594 let PendingOnionMessage { contents, destination, reply_path } = message;
1596 let (contents, destination, reply_path) = message;
1597 let _ = self.find_path_and_enqueue_onion_message(
1598 contents, destination, reply_path, format_args!("when sending OffersMessage")
1602 // Enqueue any initiating `CustomMessage`s to send.
1603 for message in self.custom_handler.release_pending_custom_messages() {
1604 #[cfg(not(c_bindings))]
1605 let PendingOnionMessage { contents, destination, reply_path } = message;
1607 let (contents, destination, reply_path) = message;
1608 let _ = self.find_path_and_enqueue_onion_message(
1609 contents, destination, reply_path, format_args!("when sending CustomMessage")
1613 self.message_recipients.lock().unwrap()
1614 .get_mut(&peer_node_id)
1615 .and_then(|buffer| buffer.dequeue_message())
1619 // TODO: parameterize the below Simple* types with OnionMessenger and handle the messages it
1621 /// Useful for simplifying the parameters of [`SimpleArcChannelManager`] and
1622 /// [`SimpleArcPeerManager`]. See their docs for more details.
1624 /// This is not exported to bindings users as type aliases aren't supported in most languages.
1626 /// [`SimpleArcChannelManager`]: crate::ln::channelmanager::SimpleArcChannelManager
1627 /// [`SimpleArcPeerManager`]: crate::ln::peer_handler::SimpleArcPeerManager
1628 #[cfg(not(c_bindings))]
1629 pub type SimpleArcOnionMessenger<M, T, F, L> = OnionMessenger<
1633 Arc<SimpleArcChannelManager<M, T, F, L>>,
1634 Arc<DefaultMessageRouter<Arc<NetworkGraph<Arc<L>>>, Arc<L>, Arc<KeysManager>>>,
1635 Arc<SimpleArcChannelManager<M, T, F, L>>,
1636 Arc<SimpleArcChannelManager<M, T, F, L>>,
1637 IgnoringMessageHandler
1640 /// Useful for simplifying the parameters of [`SimpleRefChannelManager`] and
1641 /// [`SimpleRefPeerManager`]. See their docs for more details.
1643 /// This is not exported to bindings users as type aliases aren't supported in most languages.
1645 /// [`SimpleRefChannelManager`]: crate::ln::channelmanager::SimpleRefChannelManager
1646 /// [`SimpleRefPeerManager`]: crate::ln::peer_handler::SimpleRefPeerManager
1647 #[cfg(not(c_bindings))]
1648 pub type SimpleRefOnionMessenger<
1649 'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, 'i, 'j, M, T, F, L
1654 &'i SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, M, T, F, L>,
1655 &'j DefaultMessageRouter<&'g NetworkGraph<&'b L>, &'b L, &'a KeysManager>,
1656 &'i SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, M, T, F, L>,
1657 &'i SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, M, T, F, L>,
1658 IgnoringMessageHandler
1661 /// Construct onion packet payloads and keys for sending an onion message along the given
1662 /// `unblinded_path` to the given `destination`.
1663 fn packet_payloads_and_keys<T: OnionMessageContents, S: secp256k1::Signing + secp256k1::Verification>(
1664 secp_ctx: &Secp256k1<S>, unblinded_path: &[PublicKey], destination: Destination, message: T,
1665 mut reply_path: Option<BlindedPath>, session_priv: &SecretKey
1666 ) -> Result<(Vec<(Payload<T>, [u8; 32])>, Vec<onion_utils::OnionKeys>), SendError> {
1667 let num_hops = unblinded_path.len() + destination.num_hops();
1668 let mut payloads = Vec::with_capacity(num_hops);
1669 let mut onion_packet_keys = Vec::with_capacity(num_hops);
1671 let (mut intro_node_id_blinding_pt, num_blinded_hops) = match &destination {
1672 Destination::Node(_) => (None, 0),
1673 Destination::BlindedPath(BlindedPath { introduction_node, blinding_point, blinded_hops }) => {
1674 let introduction_node_id = match introduction_node {
1675 IntroductionNode::NodeId(pubkey) => pubkey,
1676 IntroductionNode::DirectedShortChannelId(..) => {
1677 return Err(SendError::UnresolvedIntroductionNode);
1680 (Some((*introduction_node_id, *blinding_point)), blinded_hops.len())
1683 let num_unblinded_hops = num_hops - num_blinded_hops;
1685 let mut unblinded_path_idx = 0;
1686 let mut blinded_path_idx = 0;
1687 let mut prev_control_tlvs_ss = None;
1688 let mut final_control_tlvs = None;
1689 utils::construct_keys_callback(secp_ctx, unblinded_path.iter(), Some(destination), session_priv,
1690 |_, onion_packet_ss, ephemeral_pubkey, control_tlvs_ss, unblinded_pk_opt, enc_payload_opt| {
1691 if num_unblinded_hops != 0 && unblinded_path_idx < num_unblinded_hops {
1692 if let Some(ss) = prev_control_tlvs_ss.take() {
1693 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(
1695 next_hop: NextMessageHop::NodeId(unblinded_pk_opt.unwrap()),
1696 next_blinding_override: None,
1700 prev_control_tlvs_ss = Some(control_tlvs_ss);
1701 unblinded_path_idx += 1;
1702 } else if let Some((intro_node_id, blinding_pt)) = intro_node_id_blinding_pt.take() {
1703 if let Some(control_tlvs_ss) = prev_control_tlvs_ss.take() {
1704 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
1705 next_hop: NextMessageHop::NodeId(intro_node_id),
1706 next_blinding_override: Some(blinding_pt),
1707 })), control_tlvs_ss));
1710 if blinded_path_idx < num_blinded_hops.saturating_sub(1) && enc_payload_opt.is_some() {
1711 payloads.push((Payload::Forward(ForwardControlTlvs::Blinded(enc_payload_opt.unwrap())),
1713 blinded_path_idx += 1;
1714 } else if let Some(encrypted_payload) = enc_payload_opt {
1715 final_control_tlvs = Some(ReceiveControlTlvs::Blinded(encrypted_payload));
1716 prev_control_tlvs_ss = Some(control_tlvs_ss);
1719 let (rho, mu) = onion_utils::gen_rho_mu_from_shared_secret(onion_packet_ss.as_ref());
1720 onion_packet_keys.push(onion_utils::OnionKeys {
1722 shared_secret: onion_packet_ss,
1724 blinding_factor: [0; 32],
1730 ).map_err(|e| SendError::Secp256k1(e))?;
1732 if let Some(control_tlvs) = final_control_tlvs {
1733 payloads.push((Payload::Receive {
1735 reply_path: reply_path.take(),
1737 }, prev_control_tlvs_ss.unwrap()));
1739 payloads.push((Payload::Receive {
1740 control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id: None, }),
1741 reply_path: reply_path.take(),
1743 }, prev_control_tlvs_ss.unwrap()));
1746 Ok((payloads, onion_packet_keys))
1749 /// Errors if the serialized payload size exceeds onion_message::BIG_PACKET_HOP_DATA_LEN
1750 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, ()> {
1752 // "`len` allows larger messages to be sent than the standard 1300 bytes allowed for an HTLC
1753 // onion, but this should be used sparingly as it is reduces anonymity set, hence the
1754 // recommendation that it either look like an HTLC onion, or if larger, be a fixed size."
1755 let payloads_ser_len = onion_utils::payloads_serialized_length(&payloads);
1756 let hop_data_len = if payloads_ser_len <= SMALL_PACKET_HOP_DATA_LEN {
1757 SMALL_PACKET_HOP_DATA_LEN
1758 } else if payloads_ser_len <= BIG_PACKET_HOP_DATA_LEN {
1759 BIG_PACKET_HOP_DATA_LEN
1760 } else { return Err(()) };
1762 onion_utils::construct_onion_message_packet::<_, _>(
1763 payloads, onion_keys, prng_seed, hop_data_len)