1 // This file is Copyright its original authors, visible in version control
4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
7 // You may not use this file except in accordance with one or both of these
10 //! LDK sends, receives, and forwards onion messages via the [`OnionMessenger`]. See its docs for
13 use bitcoin::hashes::{Hash, HashEngine};
14 use bitcoin::hashes::hmac::{Hmac, HmacEngine};
15 use bitcoin::hashes::sha256::Hash as Sha256;
16 use bitcoin::secp256k1::{self, PublicKey, Scalar, Secp256k1, SecretKey};
18 use crate::blinded_path::BlindedPath;
19 use crate::blinded_path::message::{advance_path_by_one, ForwardTlvs, ReceiveTlvs};
20 use crate::blinded_path::utils;
21 use crate::events::{Event, EventHandler, EventsProvider};
22 use crate::sign::{EntropySource, KeysManager, NodeSigner, Recipient};
23 #[cfg(not(c_bindings))]
24 use crate::ln::channelmanager::{SimpleArcChannelManager, SimpleRefChannelManager};
25 use crate::ln::features::{InitFeatures, NodeFeatures};
26 use crate::ln::msgs::{self, OnionMessage, OnionMessageHandler, SocketAddress};
27 use crate::ln::onion_utils;
28 use crate::ln::peer_handler::IgnoringMessageHandler;
29 use crate::routing::gossip::{NetworkGraph, NodeId};
30 pub use super::packet::OnionMessageContents;
31 use super::packet::ParsedOnionMessageContents;
32 use super::offers::OffersMessageHandler;
33 use super::packet::{BIG_PACKET_HOP_DATA_LEN, ForwardControlTlvs, Packet, Payload, ReceiveControlTlvs, SMALL_PACKET_HOP_DATA_LEN};
34 use crate::util::logger::Logger;
35 use crate::util::ser::Writeable;
40 use crate::sync::{Arc, Mutex};
41 use crate::prelude::*;
43 pub(super) const MAX_TIMER_TICKS: usize = 2;
45 /// A sender, receiver and forwarder of [`OnionMessage`]s.
47 /// # Handling Messages
49 /// `OnionMessenger` implements [`OnionMessageHandler`], making it responsible for either forwarding
50 /// messages to peers or delegating to the appropriate handler for the message type. Currently, the
51 /// available handlers are:
52 /// * [`OffersMessageHandler`], for responding to [`InvoiceRequest`]s and paying [`Bolt12Invoice`]s
53 /// * [`CustomOnionMessageHandler`], for handling user-defined message types
55 /// # Sending Messages
57 /// [`OnionMessage`]s are sent initially using [`OnionMessenger::send_onion_message`]. When handling
58 /// a message, the matched handler may return a response message which `OnionMessenger` will send
64 /// # extern crate bitcoin;
65 /// # use bitcoin::hashes::_export::_core::time::Duration;
66 /// # use bitcoin::hashes::hex::FromHex;
67 /// # use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey, self};
68 /// # use lightning::blinded_path::BlindedPath;
69 /// # use lightning::sign::{EntropySource, KeysManager};
70 /// # use lightning::ln::peer_handler::IgnoringMessageHandler;
71 /// # use lightning::onion_message::{OnionMessageContents, Destination, MessageRouter, OnionMessagePath, OnionMessenger};
72 /// # use lightning::util::logger::{Logger, Record};
73 /// # use lightning::util::ser::{Writeable, Writer};
74 /// # use lightning::io;
75 /// # use std::sync::Arc;
76 /// # struct FakeLogger;
77 /// # impl Logger for FakeLogger {
78 /// # fn log(&self, record: Record) { println!("{:?}" , record); }
80 /// # struct FakeMessageRouter {}
81 /// # impl MessageRouter for FakeMessageRouter {
82 /// # fn find_path(&self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination) -> Result<OnionMessagePath, ()> {
83 /// # let secp_ctx = Secp256k1::new();
84 /// # let node_secret = SecretKey::from_slice(&<Vec<u8>>::from_hex("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
85 /// # let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
86 /// # let hop_node_id2 = hop_node_id1;
87 /// # Ok(OnionMessagePath {
88 /// # intermediate_nodes: vec![hop_node_id1, hop_node_id2],
90 /// # first_node_addresses: None,
93 /// # fn create_blinded_paths<ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification>(
94 /// # &self, _recipient: PublicKey, _peers: Vec<PublicKey>, _entropy_source: &ES, _secp_ctx: &Secp256k1<T>
95 /// # ) -> Result<Vec<BlindedPath>, ()> {
99 /// # let seed = [42u8; 32];
100 /// # let time = Duration::from_secs(123456);
101 /// # let keys_manager = KeysManager::new(&seed, time.as_secs(), time.subsec_nanos());
102 /// # let logger = Arc::new(FakeLogger {});
103 /// # let node_secret = SecretKey::from_slice(&<Vec<u8>>::from_hex("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
104 /// # let secp_ctx = Secp256k1::new();
105 /// # let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
106 /// # let (hop_node_id3, hop_node_id4) = (hop_node_id1, hop_node_id1);
107 /// # let destination_node_id = hop_node_id1;
108 /// # let message_router = Arc::new(FakeMessageRouter {});
109 /// # let custom_message_handler = IgnoringMessageHandler {};
110 /// # let offers_message_handler = IgnoringMessageHandler {};
111 /// // Create the onion messenger. This must use the same `keys_manager` as is passed to your
112 /// // ChannelManager.
113 /// let onion_messenger = OnionMessenger::new(
114 /// &keys_manager, &keys_manager, logger, message_router, &offers_message_handler,
115 /// &custom_message_handler
118 /// # #[derive(Debug)]
119 /// # struct YourCustomMessage {}
120 /// impl Writeable for YourCustomMessage {
121 /// fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
123 /// // Write your custom onion message to `w`
126 /// impl OnionMessageContents for YourCustomMessage {
127 /// fn tlv_type(&self) -> u64 {
128 /// # let your_custom_message_type = 42;
129 /// your_custom_message_type
132 /// // Send a custom onion message to a node id.
133 /// let destination = Destination::Node(destination_node_id);
134 /// let reply_path = None;
135 /// # let message = YourCustomMessage {};
136 /// onion_messenger.send_onion_message(message, destination, reply_path);
138 /// // Create a blinded path to yourself, for someone to send an onion message to.
139 /// # let your_node_id = hop_node_id1;
140 /// let hops = [hop_node_id3, hop_node_id4, your_node_id];
141 /// let blinded_path = BlindedPath::new_for_message(&hops, &keys_manager, &secp_ctx).unwrap();
143 /// // Send a custom onion message to a blinded path.
144 /// let destination = Destination::BlindedPath(blinded_path);
145 /// let reply_path = None;
146 /// # let message = YourCustomMessage {};
147 /// onion_messenger.send_onion_message(message, destination, reply_path);
150 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
151 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
152 pub struct OnionMessenger<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref>
154 ES::Target: EntropySource,
155 NS::Target: NodeSigner,
157 MR::Target: MessageRouter,
158 OMH::Target: OffersMessageHandler,
159 CMH::Target: CustomOnionMessageHandler,
164 message_recipients: Mutex<HashMap<PublicKey, OnionMessageRecipient>>,
165 secp_ctx: Secp256k1<secp256k1::All>,
171 /// [`OnionMessage`]s buffered to be sent.
172 enum OnionMessageRecipient {
173 /// Messages for a node connected as a peer.
174 ConnectedPeer(VecDeque<OnionMessage>),
176 /// Messages for a node that is not yet connected, which are dropped after [`MAX_TIMER_TICKS`]
177 /// and tracked here.
178 PendingConnection(VecDeque<OnionMessage>, Option<Vec<SocketAddress>>, usize),
181 impl OnionMessageRecipient {
182 fn pending_connection(addresses: Vec<SocketAddress>) -> Self {
183 Self::PendingConnection(VecDeque::new(), Some(addresses), 0)
186 fn pending_messages(&self) -> &VecDeque<OnionMessage> {
188 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
189 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
193 fn enqueue_message(&mut self, message: OnionMessage) {
194 let pending_messages = match self {
195 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
196 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
199 pending_messages.push_back(message);
202 fn dequeue_message(&mut self) -> Option<OnionMessage> {
203 let pending_messages = match self {
204 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
205 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => {
206 debug_assert!(false);
211 pending_messages.pop_front()
215 fn release_pending_messages(&mut self) -> VecDeque<OnionMessage> {
216 let pending_messages = match self {
217 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
218 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
221 core::mem::take(pending_messages)
224 fn mark_connected(&mut self) {
225 if let OnionMessageRecipient::PendingConnection(pending_messages, _, _) = self {
226 let mut new_pending_messages = VecDeque::new();
227 core::mem::swap(pending_messages, &mut new_pending_messages);
228 *self = OnionMessageRecipient::ConnectedPeer(new_pending_messages);
232 fn is_connected(&self) -> bool {
234 OnionMessageRecipient::ConnectedPeer(..) => true,
235 OnionMessageRecipient::PendingConnection(..) => false,
240 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
242 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
243 /// enqueued for sending.
244 #[cfg(not(c_bindings))]
245 pub struct PendingOnionMessage<T: OnionMessageContents> {
246 /// The message contents to send in an [`OnionMessage`].
249 /// The destination of the message.
250 pub destination: Destination,
252 /// A reply path to include in the [`OnionMessage`] for a response.
253 pub reply_path: Option<BlindedPath>,
257 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
259 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
260 /// enqueued for sending.
261 pub type PendingOnionMessage<T: OnionMessageContents> = (T, Destination, Option<BlindedPath>);
263 pub(crate) fn new_pending_onion_message<T: OnionMessageContents>(
264 contents: T, destination: Destination, reply_path: Option<BlindedPath>
265 ) -> PendingOnionMessage<T> {
266 #[cfg(not(c_bindings))]
267 return PendingOnionMessage { contents, destination, reply_path };
269 return (contents, destination, reply_path);
272 /// A trait defining behavior for routing an [`OnionMessage`].
273 pub trait MessageRouter {
274 /// Returns a route for sending an [`OnionMessage`] to the given [`Destination`].
276 &self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
277 ) -> Result<OnionMessagePath, ()>;
279 /// Creates [`BlindedPath`]s to the `recipient` node. The nodes in `peers` are assumed to be
280 /// direct peers with the `recipient`.
281 fn create_blinded_paths<
282 ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification
284 &self, recipient: PublicKey, peers: Vec<PublicKey>, entropy_source: &ES,
285 secp_ctx: &Secp256k1<T>
286 ) -> Result<Vec<BlindedPath>, ()>;
289 /// A [`MessageRouter`] that can only route to a directly connected [`Destination`].
290 pub struct DefaultMessageRouter<G: Deref<Target=NetworkGraph<L>>, L: Deref>
297 impl<G: Deref<Target=NetworkGraph<L>>, L: Deref> DefaultMessageRouter<G, L>
301 /// Creates a [`DefaultMessageRouter`] using the given [`NetworkGraph`].
302 pub fn new(network_graph: G) -> Self {
303 Self { network_graph }
307 impl<G: Deref<Target=NetworkGraph<L>>, L: Deref> MessageRouter for DefaultMessageRouter<G, L>
312 &self, _sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
313 ) -> Result<OnionMessagePath, ()> {
314 let first_node = destination.first_node();
315 if peers.contains(&first_node) {
316 Ok(OnionMessagePath {
317 intermediate_nodes: vec![], destination, first_node_addresses: None
320 let network_graph = self.network_graph.deref().read_only();
321 let node_announcement = network_graph
322 .node(&NodeId::from_pubkey(&first_node))
323 .and_then(|node_info| node_info.announcement_info.as_ref())
324 .and_then(|announcement_info| announcement_info.announcement_message.as_ref())
325 .map(|node_announcement| &node_announcement.contents);
327 match node_announcement {
328 Some(node_announcement) if node_announcement.features.supports_onion_messages() => {
329 let first_node_addresses = Some(node_announcement.addresses.clone());
330 Ok(OnionMessagePath {
331 intermediate_nodes: vec![], destination, first_node_addresses
339 fn create_blinded_paths<
340 ES: EntropySource + ?Sized, T: secp256k1::Signing + secp256k1::Verification
342 &self, recipient: PublicKey, peers: Vec<PublicKey>, entropy_source: &ES,
343 secp_ctx: &Secp256k1<T>
344 ) -> Result<Vec<BlindedPath>, ()> {
345 // Limit the number of blinded paths that are computed.
346 const MAX_PATHS: usize = 3;
348 // Ensure peers have at least three channels so that it is more difficult to infer the
349 // recipient's node_id.
350 const MIN_PEER_CHANNELS: usize = 3;
352 let network_graph = self.network_graph.deref().read_only();
353 let paths = peers.iter()
354 // Limit to peers with announced channels
357 .node(&NodeId::from_pubkey(pubkey))
358 .map(|info| &info.channels[..])
359 .map(|channels| channels.len() >= MIN_PEER_CHANNELS)
362 .map(|pubkey| vec![*pubkey, recipient])
363 .map(|node_pks| BlindedPath::new_for_message(&node_pks, entropy_source, secp_ctx))
365 .collect::<Result<Vec<_>, _>>();
368 Ok(paths) if !paths.is_empty() => Ok(paths),
370 if network_graph.nodes().contains_key(&NodeId::from_pubkey(&recipient)) {
371 BlindedPath::one_hop_for_message(recipient, entropy_source, secp_ctx)
372 .map(|path| vec![path])
381 /// A path for sending an [`OnionMessage`].
383 pub struct OnionMessagePath {
384 /// Nodes on the path between the sender and the destination.
385 pub intermediate_nodes: Vec<PublicKey>,
387 /// The recipient of the message.
388 pub destination: Destination,
390 /// Addresses that may be used to connect to [`OnionMessagePath::first_node`].
392 /// Only needs to be set if a connection to the node is required. [`OnionMessenger`] may use
393 /// this to initiate such a connection.
394 pub first_node_addresses: Option<Vec<SocketAddress>>,
397 impl OnionMessagePath {
398 /// Returns the first node in the path.
399 pub fn first_node(&self) -> PublicKey {
400 self.intermediate_nodes
403 .unwrap_or_else(|| self.destination.first_node())
407 /// The destination of an onion message.
409 pub enum Destination {
410 /// We're sending this onion message to a node.
412 /// We're sending this onion message to a blinded path.
413 BlindedPath(BlindedPath),
417 pub(super) fn num_hops(&self) -> usize {
419 Destination::Node(_) => 1,
420 Destination::BlindedPath(BlindedPath { blinded_hops, .. }) => blinded_hops.len(),
424 fn first_node(&self) -> PublicKey {
426 Destination::Node(node_id) => *node_id,
427 Destination::BlindedPath(BlindedPath { introduction_node_id: node_id, .. }) => *node_id,
432 /// Result of successfully [sending an onion message].
434 /// [sending an onion message]: OnionMessenger::send_onion_message
435 #[derive(Debug, PartialEq, Eq)]
436 pub enum SendSuccess {
437 /// The message was buffered and will be sent once it is processed by
438 /// [`OnionMessageHandler::next_onion_message_for_peer`].
440 /// The message was buffered and will be sent once the node is connected as a peer and it is
441 /// processed by [`OnionMessageHandler::next_onion_message_for_peer`].
442 BufferedAwaitingConnection(PublicKey),
445 /// Errors that may occur when [sending an onion message].
447 /// [sending an onion message]: OnionMessenger::send_onion_message
448 #[derive(Debug, PartialEq, Eq)]
450 /// Errored computing onion message packet keys.
451 Secp256k1(secp256k1::Error),
452 /// Because implementations such as Eclair will drop onion messages where the message packet
453 /// exceeds 32834 bytes, we refuse to send messages where the packet exceeds this size.
455 /// The provided [`Destination`] was an invalid [`BlindedPath`] due to not having any blinded
458 /// The first hop is not a peer and doesn't have a known [`SocketAddress`].
459 InvalidFirstHop(PublicKey),
460 /// A path from the sender to the destination could not be found by the [`MessageRouter`].
462 /// Onion message contents must have a TLV type >= 64.
464 /// Our next-hop peer's buffer was full or our total outbound buffer was full.
466 /// Failed to retrieve our node id from the provided [`NodeSigner`].
468 /// [`NodeSigner`]: crate::sign::NodeSigner
470 /// We attempted to send to a blinded path where we are the introduction node, and failed to
471 /// advance the blinded path to make the second hop the new introduction node. Either
472 /// [`NodeSigner::ecdh`] failed, we failed to tweak the current blinding point to get the
473 /// new blinding point, or we were attempting to send to ourselves.
474 BlindedPathAdvanceFailed,
477 /// Handler for custom onion messages. If you are using [`SimpleArcOnionMessenger`],
478 /// [`SimpleRefOnionMessenger`], or prefer to ignore inbound custom onion messages,
479 /// [`IgnoringMessageHandler`] must be provided to [`OnionMessenger::new`]. Otherwise, a custom
480 /// implementation of this trait must be provided, with [`CustomMessage`] specifying the supported
483 /// See [`OnionMessenger`] for example usage.
485 /// [`IgnoringMessageHandler`]: crate::ln::peer_handler::IgnoringMessageHandler
486 /// [`CustomMessage`]: Self::CustomMessage
487 pub trait CustomOnionMessageHandler {
488 /// The message known to the handler. To support multiple message types, you may want to make this
489 /// an enum with a variant for each supported message.
490 type CustomMessage: OnionMessageContents;
492 /// Called with the custom message that was received, returning a response to send, if any.
494 /// The returned [`Self::CustomMessage`], if any, is enqueued to be sent by [`OnionMessenger`].
495 fn handle_custom_message(&self, msg: Self::CustomMessage) -> Option<Self::CustomMessage>;
497 /// Read a custom message of type `message_type` from `buffer`, returning `Ok(None)` if the
498 /// message type is unknown.
499 fn read_custom_message<R: io::Read>(&self, message_type: u64, buffer: &mut R) -> Result<Option<Self::CustomMessage>, msgs::DecodeError>;
501 /// Releases any [`Self::CustomMessage`]s that need to be sent.
503 /// Typically, this is used for messages initiating a message flow rather than in response to
504 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
505 #[cfg(not(c_bindings))]
506 fn release_pending_custom_messages(&self) -> Vec<PendingOnionMessage<Self::CustomMessage>>;
508 /// Releases any [`Self::CustomMessage`]s that need to be sent.
510 /// Typically, this is used for messages initiating a message flow rather than in response to
511 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
513 fn release_pending_custom_messages(&self) -> Vec<(Self::CustomMessage, Destination, Option<BlindedPath>)>;
516 /// A processed incoming onion message, containing either a Forward (another onion message)
517 /// or a Receive payload with decrypted contents.
518 pub enum PeeledOnion<T: OnionMessageContents> {
519 /// Forwarded onion, with the next node id and a new onion
520 Forward(PublicKey, OnionMessage),
521 /// Received onion message, with decrypted contents, path_id, and reply path
522 Receive(ParsedOnionMessageContents<T>, Option<[u8; 32]>, Option<BlindedPath>)
525 /// Creates an [`OnionMessage`] with the given `contents` for sending to the destination of
528 /// Returns the node id of the peer to send the message to, the message itself, and any addresses
529 /// need to connect to the first node.
530 pub fn create_onion_message<ES: Deref, NS: Deref, T: OnionMessageContents>(
531 entropy_source: &ES, node_signer: &NS, secp_ctx: &Secp256k1<secp256k1::All>,
532 path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
533 ) -> Result<(PublicKey, OnionMessage, Option<Vec<SocketAddress>>), SendError>
535 ES::Target: EntropySource,
536 NS::Target: NodeSigner,
538 let OnionMessagePath { intermediate_nodes, mut destination, first_node_addresses } = path;
539 if let Destination::BlindedPath(BlindedPath { ref blinded_hops, .. }) = destination {
540 if blinded_hops.is_empty() {
541 return Err(SendError::TooFewBlindedHops);
545 if contents.tlv_type() < 64 { return Err(SendError::InvalidMessage) }
547 // If we are sending straight to a blinded path and we are the introduction node, we need to
548 // advance the blinded path by 1 hop so the second hop is the new introduction node.
549 if intermediate_nodes.len() == 0 {
550 if let Destination::BlindedPath(ref mut blinded_path) = destination {
551 let our_node_id = node_signer.get_node_id(Recipient::Node)
552 .map_err(|()| SendError::GetNodeIdFailed)?;
553 if blinded_path.introduction_node_id == our_node_id {
554 advance_path_by_one(blinded_path, node_signer, &secp_ctx)
555 .map_err(|()| SendError::BlindedPathAdvanceFailed)?;
560 let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
561 let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
562 let (first_node_id, blinding_point) = if let Some(first_node_id) = intermediate_nodes.first() {
563 (*first_node_id, PublicKey::from_secret_key(&secp_ctx, &blinding_secret))
566 Destination::Node(pk) => (pk, PublicKey::from_secret_key(&secp_ctx, &blinding_secret)),
567 Destination::BlindedPath(BlindedPath { introduction_node_id, blinding_point, .. }) =>
568 (introduction_node_id, blinding_point),
571 let (packet_payloads, packet_keys) = packet_payloads_and_keys(
572 &secp_ctx, &intermediate_nodes, destination, contents, reply_path, &blinding_secret)
573 .map_err(|e| SendError::Secp256k1(e))?;
575 let prng_seed = entropy_source.get_secure_random_bytes();
576 let onion_routing_packet = construct_onion_message_packet(
577 packet_payloads, packet_keys, prng_seed).map_err(|()| SendError::TooBigPacket)?;
579 let message = OnionMessage { blinding_point, onion_routing_packet };
580 Ok((first_node_id, message, first_node_addresses))
583 /// Decode one layer of an incoming [`OnionMessage`].
585 /// Returns either the next layer of the onion for forwarding or the decrypted content for the
587 pub fn peel_onion_message<NS: Deref, L: Deref, CMH: Deref>(
588 msg: &OnionMessage, secp_ctx: &Secp256k1<secp256k1::All>, node_signer: NS, logger: L,
590 ) -> Result<PeeledOnion<<<CMH>::Target as CustomOnionMessageHandler>::CustomMessage>, ()>
592 NS::Target: NodeSigner,
594 CMH::Target: CustomOnionMessageHandler,
596 let control_tlvs_ss = match node_signer.ecdh(Recipient::Node, &msg.blinding_point, None) {
599 log_error!(logger, "Failed to retrieve node secret: {:?}", e);
603 let onion_decode_ss = {
604 let blinding_factor = {
605 let mut hmac = HmacEngine::<Sha256>::new(b"blinded_node_id");
606 hmac.input(control_tlvs_ss.as_ref());
607 Hmac::from_engine(hmac).to_byte_array()
609 match node_signer.ecdh(Recipient::Node, &msg.onion_routing_packet.public_key,
610 Some(&Scalar::from_be_bytes(blinding_factor).unwrap()))
612 Ok(ss) => ss.secret_bytes(),
614 log_trace!(logger, "Failed to compute onion packet shared secret");
619 match onion_utils::decode_next_untagged_hop(
620 onion_decode_ss, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
621 (control_tlvs_ss, custom_handler.deref(), logger.deref())
623 Ok((Payload::Receive::<ParsedOnionMessageContents<<<CMH as Deref>::Target as CustomOnionMessageHandler>::CustomMessage>> {
624 message, control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id }), reply_path,
626 Ok(PeeledOnion::Receive(message, path_id, reply_path))
628 Ok((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
629 next_node_id, next_blinding_override
630 })), Some((next_hop_hmac, new_packet_bytes)))) => {
631 // TODO: we need to check whether `next_node_id` is our node, in which case this is a dummy
632 // blinded hop and this onion message is destined for us. In this situation, we should keep
633 // unwrapping the onion layers to get to the final payload. Since we don't have the option
634 // of creating blinded paths with dummy hops currently, we should be ok to not handle this
636 let new_pubkey = match onion_utils::next_hop_pubkey(&secp_ctx, msg.onion_routing_packet.public_key, &onion_decode_ss) {
639 log_trace!(logger, "Failed to compute next hop packet pubkey: {}", e);
643 let outgoing_packet = Packet {
645 public_key: new_pubkey,
646 hop_data: new_packet_bytes,
649 let onion_message = OnionMessage {
650 blinding_point: match next_blinding_override {
651 Some(blinding_point) => blinding_point,
653 match onion_utils::next_hop_pubkey(
654 &secp_ctx, msg.blinding_point, control_tlvs_ss.as_ref()
658 log_trace!(logger, "Failed to compute next blinding point: {}", e);
664 onion_routing_packet: outgoing_packet,
667 Ok(PeeledOnion::Forward(next_node_id, onion_message))
670 log_trace!(logger, "Errored decoding onion message packet: {:?}", e);
674 log_trace!(logger, "Received bogus onion message packet, either the sender encoded a final hop as a forwarding hop or vice versa");
680 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref>
681 OnionMessenger<ES, NS, L, MR, OMH, CMH>
683 ES::Target: EntropySource,
684 NS::Target: NodeSigner,
686 MR::Target: MessageRouter,
687 OMH::Target: OffersMessageHandler,
688 CMH::Target: CustomOnionMessageHandler,
690 /// Constructs a new `OnionMessenger` to send, forward, and delegate received onion messages to
691 /// their respective handlers.
693 entropy_source: ES, node_signer: NS, logger: L, message_router: MR, offers_handler: OMH,
696 let mut secp_ctx = Secp256k1::new();
697 secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
701 message_recipients: Mutex::new(HashMap::new()),
710 /// Sends an [`OnionMessage`] with the given `contents` to `destination`.
712 /// See [`OnionMessenger`] for example usage.
713 pub fn send_onion_message<T: OnionMessageContents>(
714 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>
715 ) -> Result<SendSuccess, SendError> {
716 self.find_path_and_enqueue_onion_message(
717 contents, destination, reply_path, format_args!("")
721 fn find_path_and_enqueue_onion_message<T: OnionMessageContents>(
722 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>,
723 log_suffix: fmt::Arguments
724 ) -> Result<SendSuccess, SendError> {
725 let result = self.find_path(destination)
726 .and_then(|path| self.enqueue_onion_message(path, contents, reply_path, log_suffix));
728 match result.as_ref() {
729 Err(SendError::GetNodeIdFailed) => {
730 log_warn!(self.logger, "Unable to retrieve node id {}", log_suffix);
732 Err(SendError::PathNotFound) => {
733 log_trace!(self.logger, "Failed to find path {}", log_suffix);
736 log_trace!(self.logger, "Failed sending onion message {}: {:?}", log_suffix, e);
738 Ok(SendSuccess::Buffered) => {
739 log_trace!(self.logger, "Buffered onion message {}", log_suffix);
741 Ok(SendSuccess::BufferedAwaitingConnection(node_id)) => {
743 self.logger, "Buffered onion message waiting on peer connection {}: {:?}",
752 fn find_path(&self, destination: Destination) -> Result<OnionMessagePath, SendError> {
753 let sender = self.node_signer
754 .get_node_id(Recipient::Node)
755 .map_err(|_| SendError::GetNodeIdFailed)?;
757 let peers = self.message_recipients.lock().unwrap()
759 .filter(|(_, recipient)| matches!(recipient, OnionMessageRecipient::ConnectedPeer(_)))
760 .map(|(node_id, _)| *node_id)
764 .find_path(sender, peers, destination)
765 .map_err(|_| SendError::PathNotFound)
768 fn enqueue_onion_message<T: OnionMessageContents>(
769 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
770 log_suffix: fmt::Arguments
771 ) -> Result<SendSuccess, SendError> {
772 log_trace!(self.logger, "Constructing onion message {}: {:?}", log_suffix, contents);
774 let (first_node_id, onion_message, addresses) = create_onion_message(
775 &self.entropy_source, &self.node_signer, &self.secp_ctx, path, contents, reply_path
778 let mut message_recipients = self.message_recipients.lock().unwrap();
779 if outbound_buffer_full(&first_node_id, &message_recipients) {
780 return Err(SendError::BufferFull);
783 match message_recipients.entry(first_node_id) {
784 hash_map::Entry::Vacant(e) => match addresses {
785 None => Err(SendError::InvalidFirstHop(first_node_id)),
787 e.insert(OnionMessageRecipient::pending_connection(addresses))
788 .enqueue_message(onion_message);
789 Ok(SendSuccess::BufferedAwaitingConnection(first_node_id))
792 hash_map::Entry::Occupied(mut e) => {
793 e.get_mut().enqueue_message(onion_message);
794 if e.get().is_connected() {
795 Ok(SendSuccess::Buffered)
797 Ok(SendSuccess::BufferedAwaitingConnection(first_node_id))
804 pub(super) fn send_onion_message_using_path<T: OnionMessageContents>(
805 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>
806 ) -> Result<SendSuccess, SendError> {
807 self.enqueue_onion_message(path, contents, reply_path, format_args!(""))
810 fn handle_onion_message_response<T: OnionMessageContents>(
811 &self, response: Option<T>, reply_path: Option<BlindedPath>, log_suffix: fmt::Arguments
813 if let Some(response) = response {
815 Some(reply_path) => {
816 let _ = self.find_path_and_enqueue_onion_message(
817 response, Destination::BlindedPath(reply_path), None, log_suffix
821 log_trace!(self.logger, "Missing reply path {}", log_suffix);
828 pub(super) fn release_pending_msgs(&self) -> HashMap<PublicKey, VecDeque<OnionMessage>> {
829 let mut message_recipients = self.message_recipients.lock().unwrap();
830 let mut msgs = HashMap::new();
831 // We don't want to disconnect the peers by removing them entirely from the original map, so we
832 // release the pending message buffers individually.
833 for (node_id, recipient) in &mut *message_recipients {
834 msgs.insert(*node_id, recipient.release_pending_messages());
840 fn outbound_buffer_full(peer_node_id: &PublicKey, buffer: &HashMap<PublicKey, OnionMessageRecipient>) -> bool {
841 const MAX_TOTAL_BUFFER_SIZE: usize = (1 << 20) * 128;
842 const MAX_PER_PEER_BUFFER_SIZE: usize = (1 << 10) * 256;
843 let mut total_buffered_bytes = 0;
844 let mut peer_buffered_bytes = 0;
845 for (pk, peer_buf) in buffer {
846 for om in peer_buf.pending_messages() {
847 let om_len = om.serialized_length();
848 if pk == peer_node_id {
849 peer_buffered_bytes += om_len;
851 total_buffered_bytes += om_len;
853 if total_buffered_bytes >= MAX_TOTAL_BUFFER_SIZE ||
854 peer_buffered_bytes >= MAX_PER_PEER_BUFFER_SIZE
863 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref> EventsProvider
864 for OnionMessenger<ES, NS, L, MR, OMH, CMH>
866 ES::Target: EntropySource,
867 NS::Target: NodeSigner,
869 MR::Target: MessageRouter,
870 OMH::Target: OffersMessageHandler,
871 CMH::Target: CustomOnionMessageHandler,
873 fn process_pending_events<H: Deref>(&self, handler: H) where H::Target: EventHandler {
874 for (node_id, recipient) in self.message_recipients.lock().unwrap().iter_mut() {
875 if let OnionMessageRecipient::PendingConnection(_, addresses, _) = recipient {
876 if let Some(addresses) = addresses.take() {
877 handler.handle_event(Event::ConnectionNeeded { node_id: *node_id, addresses });
884 impl<ES: Deref, NS: Deref, L: Deref, MR: Deref, OMH: Deref, CMH: Deref> OnionMessageHandler
885 for OnionMessenger<ES, NS, L, MR, OMH, CMH>
887 ES::Target: EntropySource,
888 NS::Target: NodeSigner,
890 MR::Target: MessageRouter,
891 OMH::Target: OffersMessageHandler,
892 CMH::Target: CustomOnionMessageHandler,
894 fn handle_onion_message(&self, _peer_node_id: &PublicKey, msg: &OnionMessage) {
895 match peel_onion_message(
896 msg, &self.secp_ctx, &*self.node_signer, &*self.logger, &*self.custom_handler
898 Ok(PeeledOnion::Receive(message, path_id, reply_path)) => {
901 "Received an onion message with path_id {:02x?} and {} reply_path: {:?}",
902 path_id, if reply_path.is_some() { "a" } else { "no" }, message);
905 ParsedOnionMessageContents::Offers(msg) => {
906 let response = self.offers_handler.handle_message(msg);
907 self.handle_onion_message_response(
908 response, reply_path, format_args!(
909 "when responding to Offers onion message with path_id {:02x?}",
914 ParsedOnionMessageContents::Custom(msg) => {
915 let response = self.custom_handler.handle_custom_message(msg);
916 self.handle_onion_message_response(
917 response, reply_path, format_args!(
918 "when responding to Custom onion message with path_id {:02x?}",
925 Ok(PeeledOnion::Forward(next_node_id, onion_message)) => {
926 let mut message_recipients = self.message_recipients.lock().unwrap();
927 if outbound_buffer_full(&next_node_id, &message_recipients) {
928 log_trace!(self.logger, "Dropping forwarded onion message to peer {:?}: outbound buffer full", next_node_id);
935 .or_insert_with(|| OnionMessageRecipient::ConnectedPeer(VecDeque::new()));
937 match message_recipients.entry(next_node_id) {
938 hash_map::Entry::Occupied(mut e) if matches!(
939 e.get(), OnionMessageRecipient::ConnectedPeer(..)
941 e.get_mut().enqueue_message(onion_message);
942 log_trace!(self.logger, "Forwarding an onion message to peer {}", next_node_id);
945 log_trace!(self.logger, "Dropping forwarded onion message to disconnected peer {:?}", next_node_id);
951 log_error!(self.logger, "Failed to process onion message {:?}", e);
956 fn peer_connected(&self, their_node_id: &PublicKey, init: &msgs::Init, _inbound: bool) -> Result<(), ()> {
957 if init.features.supports_onion_messages() {
958 self.message_recipients.lock().unwrap()
959 .entry(*their_node_id)
960 .or_insert_with(|| OnionMessageRecipient::ConnectedPeer(VecDeque::new()))
963 self.message_recipients.lock().unwrap().remove(their_node_id);
969 fn peer_disconnected(&self, their_node_id: &PublicKey) {
970 match self.message_recipients.lock().unwrap().remove(their_node_id) {
971 Some(OnionMessageRecipient::ConnectedPeer(..)) => {},
972 Some(_) => debug_assert!(false),
977 fn timer_tick_occurred(&self) {
978 let mut message_recipients = self.message_recipients.lock().unwrap();
980 // Drop any pending recipients since the last call to avoid retaining buffered messages for
982 message_recipients.retain(|_, recipient| match recipient {
983 OnionMessageRecipient::PendingConnection(_, None, ticks) => *ticks < MAX_TIMER_TICKS,
984 OnionMessageRecipient::PendingConnection(_, Some(_), _) => true,
988 // Increment a timer tick for pending recipients so that their buffered messages are dropped
989 // at MAX_TIMER_TICKS.
990 for recipient in message_recipients.values_mut() {
991 if let OnionMessageRecipient::PendingConnection(_, None, ticks) = recipient {
997 fn provided_node_features(&self) -> NodeFeatures {
998 let mut features = NodeFeatures::empty();
999 features.set_onion_messages_optional();
1003 fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
1004 let mut features = InitFeatures::empty();
1005 features.set_onion_messages_optional();
1009 // Before returning any messages to send for the peer, this method will see if any messages were
1010 // enqueued in the handler by users, find a path to the corresponding blinded path's introduction
1011 // node, and then enqueue the message for sending to the first peer in the full path.
1012 fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<OnionMessage> {
1013 // Enqueue any initiating `OffersMessage`s to send.
1014 for message in self.offers_handler.release_pending_messages() {
1015 #[cfg(not(c_bindings))]
1016 let PendingOnionMessage { contents, destination, reply_path } = message;
1018 let (contents, destination, reply_path) = message;
1019 let _ = self.find_path_and_enqueue_onion_message(
1020 contents, destination, reply_path, format_args!("when sending OffersMessage")
1024 // Enqueue any initiating `CustomMessage`s to send.
1025 for message in self.custom_handler.release_pending_custom_messages() {
1026 #[cfg(not(c_bindings))]
1027 let PendingOnionMessage { contents, destination, reply_path } = message;
1029 let (contents, destination, reply_path) = message;
1030 let _ = self.find_path_and_enqueue_onion_message(
1031 contents, destination, reply_path, format_args!("when sending CustomMessage")
1035 self.message_recipients.lock().unwrap()
1036 .get_mut(&peer_node_id)
1037 .and_then(|buffer| buffer.dequeue_message())
1041 // TODO: parameterize the below Simple* types with OnionMessenger and handle the messages it
1043 /// Useful for simplifying the parameters of [`SimpleArcChannelManager`] and
1044 /// [`SimpleArcPeerManager`]. See their docs for more details.
1046 /// This is not exported to bindings users as type aliases aren't supported in most languages.
1048 /// [`SimpleArcChannelManager`]: crate::ln::channelmanager::SimpleArcChannelManager
1049 /// [`SimpleArcPeerManager`]: crate::ln::peer_handler::SimpleArcPeerManager
1050 #[cfg(not(c_bindings))]
1051 pub type SimpleArcOnionMessenger<M, T, F, L> = OnionMessenger<
1055 Arc<DefaultMessageRouter<Arc<NetworkGraph<Arc<L>>>, Arc<L>>>,
1056 Arc<SimpleArcChannelManager<M, T, F, L>>,
1057 IgnoringMessageHandler
1060 /// Useful for simplifying the parameters of [`SimpleRefChannelManager`] and
1061 /// [`SimpleRefPeerManager`]. See their docs for more details.
1063 /// This is not exported to bindings users as type aliases aren't supported in most languages.
1065 /// [`SimpleRefChannelManager`]: crate::ln::channelmanager::SimpleRefChannelManager
1066 /// [`SimpleRefPeerManager`]: crate::ln::peer_handler::SimpleRefPeerManager
1067 #[cfg(not(c_bindings))]
1068 pub type SimpleRefOnionMessenger<
1069 'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, 'i, 'j, M, T, F, L
1074 &'i DefaultMessageRouter<&'g NetworkGraph<&'b L>, &'b L>,
1075 &'j SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, M, T, F, L>,
1076 IgnoringMessageHandler
1079 /// Construct onion packet payloads and keys for sending an onion message along the given
1080 /// `unblinded_path` to the given `destination`.
1081 fn packet_payloads_and_keys<T: OnionMessageContents, S: secp256k1::Signing + secp256k1::Verification>(
1082 secp_ctx: &Secp256k1<S>, unblinded_path: &[PublicKey], destination: Destination, message: T,
1083 mut reply_path: Option<BlindedPath>, session_priv: &SecretKey
1084 ) -> Result<(Vec<(Payload<T>, [u8; 32])>, Vec<onion_utils::OnionKeys>), secp256k1::Error> {
1085 let num_hops = unblinded_path.len() + destination.num_hops();
1086 let mut payloads = Vec::with_capacity(num_hops);
1087 let mut onion_packet_keys = Vec::with_capacity(num_hops);
1089 let (mut intro_node_id_blinding_pt, num_blinded_hops) = if let Destination::BlindedPath(BlindedPath {
1090 introduction_node_id, blinding_point, blinded_hops }) = &destination {
1091 (Some((*introduction_node_id, *blinding_point)), blinded_hops.len()) } else { (None, 0) };
1092 let num_unblinded_hops = num_hops - num_blinded_hops;
1094 let mut unblinded_path_idx = 0;
1095 let mut blinded_path_idx = 0;
1096 let mut prev_control_tlvs_ss = None;
1097 let mut final_control_tlvs = None;
1098 utils::construct_keys_callback(secp_ctx, unblinded_path.iter(), Some(destination), session_priv,
1099 |_, onion_packet_ss, ephemeral_pubkey, control_tlvs_ss, unblinded_pk_opt, enc_payload_opt| {
1100 if num_unblinded_hops != 0 && unblinded_path_idx < num_unblinded_hops {
1101 if let Some(ss) = prev_control_tlvs_ss.take() {
1102 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(
1104 next_node_id: unblinded_pk_opt.unwrap(),
1105 next_blinding_override: None,
1109 prev_control_tlvs_ss = Some(control_tlvs_ss);
1110 unblinded_path_idx += 1;
1111 } else if let Some((intro_node_id, blinding_pt)) = intro_node_id_blinding_pt.take() {
1112 if let Some(control_tlvs_ss) = prev_control_tlvs_ss.take() {
1113 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
1114 next_node_id: intro_node_id,
1115 next_blinding_override: Some(blinding_pt),
1116 })), control_tlvs_ss));
1119 if blinded_path_idx < num_blinded_hops.saturating_sub(1) && enc_payload_opt.is_some() {
1120 payloads.push((Payload::Forward(ForwardControlTlvs::Blinded(enc_payload_opt.unwrap())),
1122 blinded_path_idx += 1;
1123 } else if let Some(encrypted_payload) = enc_payload_opt {
1124 final_control_tlvs = Some(ReceiveControlTlvs::Blinded(encrypted_payload));
1125 prev_control_tlvs_ss = Some(control_tlvs_ss);
1128 let (rho, mu) = onion_utils::gen_rho_mu_from_shared_secret(onion_packet_ss.as_ref());
1129 onion_packet_keys.push(onion_utils::OnionKeys {
1131 shared_secret: onion_packet_ss,
1133 blinding_factor: [0; 32],
1141 if let Some(control_tlvs) = final_control_tlvs {
1142 payloads.push((Payload::Receive {
1144 reply_path: reply_path.take(),
1146 }, prev_control_tlvs_ss.unwrap()));
1148 payloads.push((Payload::Receive {
1149 control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id: None, }),
1150 reply_path: reply_path.take(),
1152 }, prev_control_tlvs_ss.unwrap()));
1155 Ok((payloads, onion_packet_keys))
1158 /// Errors if the serialized payload size exceeds onion_message::BIG_PACKET_HOP_DATA_LEN
1159 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, ()> {
1161 // "`len` allows larger messages to be sent than the standard 1300 bytes allowed for an HTLC
1162 // onion, but this should be used sparingly as it is reduces anonymity set, hence the
1163 // recommendation that it either look like an HTLC onion, or if larger, be a fixed size."
1164 let payloads_ser_len = onion_utils::payloads_serialized_length(&payloads);
1165 let hop_data_len = if payloads_ser_len <= SMALL_PACKET_HOP_DATA_LEN {
1166 SMALL_PACKET_HOP_DATA_LEN
1167 } else if payloads_ser_len <= BIG_PACKET_HOP_DATA_LEN {
1168 BIG_PACKET_HOP_DATA_LEN
1169 } else { return Err(()) };
1171 onion_utils::construct_onion_message_packet::<_, _>(
1172 payloads, onion_keys, prng_seed, hop_data_len)