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, NodeIdLookUp};
19 use crate::blinded_path::message::{advance_path_by_one, ForwardTlvs, NextHop, ReceiveTlvs};
20 use crate::blinded_path::utils;
21 use crate::events::{Event, EventHandler, EventsProvider};
22 use crate::sign::{EntropySource, NodeSigner, Recipient};
23 use crate::ln::features::{InitFeatures, NodeFeatures};
24 use crate::ln::msgs::{self, OnionMessage, OnionMessageHandler, SocketAddress};
25 use crate::ln::onion_utils;
26 use crate::routing::gossip::{NetworkGraph, NodeId, ReadOnlyNetworkGraph};
27 use super::packet::OnionMessageContents;
28 use super::packet::ParsedOnionMessageContents;
29 use super::offers::OffersMessageHandler;
30 use super::packet::{BIG_PACKET_HOP_DATA_LEN, ForwardControlTlvs, Packet, Payload, ReceiveControlTlvs, SMALL_PACKET_HOP_DATA_LEN};
31 use crate::util::logger::{Logger, WithContext};
32 use crate::util::ser::Writeable;
37 use crate::sync::Mutex;
38 use crate::prelude::*;
40 #[cfg(not(c_bindings))]
42 crate::sign::KeysManager,
43 crate::ln::channelmanager::{SimpleArcChannelManager, SimpleRefChannelManager},
44 crate::ln::peer_handler::IgnoringMessageHandler,
48 pub(super) const MAX_TIMER_TICKS: usize = 2;
50 /// A sender, receiver and forwarder of [`OnionMessage`]s.
52 /// # Handling Messages
54 /// `OnionMessenger` implements [`OnionMessageHandler`], making it responsible for either forwarding
55 /// messages to peers or delegating to the appropriate handler for the message type. Currently, the
56 /// available handlers are:
57 /// * [`OffersMessageHandler`], for responding to [`InvoiceRequest`]s and paying [`Bolt12Invoice`]s
58 /// * [`CustomOnionMessageHandler`], for handling user-defined message types
60 /// # Sending Messages
62 /// [`OnionMessage`]s are sent initially using [`OnionMessenger::send_onion_message`]. When handling
63 /// a message, the matched handler may return a response message which `OnionMessenger` will send
69 /// # extern crate bitcoin;
70 /// # use bitcoin::hashes::_export::_core::time::Duration;
71 /// # use bitcoin::hashes::hex::FromHex;
72 /// # use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey, self};
73 /// # use lightning::blinded_path::{BlindedPath, EmptyNodeIdLookUp};
74 /// # use lightning::sign::{EntropySource, KeysManager};
75 /// # use lightning::ln::peer_handler::IgnoringMessageHandler;
76 /// # use lightning::onion_message::messenger::{Destination, MessageRouter, OnionMessagePath, OnionMessenger};
77 /// # use lightning::onion_message::packet::OnionMessageContents;
78 /// # use lightning::util::logger::{Logger, Record};
79 /// # use lightning::util::ser::{Writeable, Writer};
80 /// # use lightning::io;
81 /// # use std::sync::Arc;
82 /// # struct FakeLogger;
83 /// # impl Logger for FakeLogger {
84 /// # fn log(&self, record: Record) { println!("{:?}" , record); }
86 /// # struct FakeMessageRouter {}
87 /// # impl MessageRouter for FakeMessageRouter {
88 /// # fn find_path(&self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination) -> Result<OnionMessagePath, ()> {
89 /// # let secp_ctx = Secp256k1::new();
90 /// # let node_secret = SecretKey::from_slice(&<Vec<u8>>::from_hex("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
91 /// # let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
92 /// # let hop_node_id2 = hop_node_id1;
93 /// # Ok(OnionMessagePath {
94 /// # intermediate_nodes: vec![hop_node_id1, hop_node_id2],
96 /// # first_node_addresses: None,
99 /// # fn create_blinded_paths<T: secp256k1::Signing + secp256k1::Verification>(
100 /// # &self, _recipient: PublicKey, _peers: Vec<PublicKey>, _secp_ctx: &Secp256k1<T>
101 /// # ) -> Result<Vec<BlindedPath>, ()> {
105 /// # let seed = [42u8; 32];
106 /// # let time = Duration::from_secs(123456);
107 /// # let keys_manager = KeysManager::new(&seed, time.as_secs(), time.subsec_nanos());
108 /// # let logger = Arc::new(FakeLogger {});
109 /// # let node_secret = SecretKey::from_slice(&<Vec<u8>>::from_hex("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
110 /// # let secp_ctx = Secp256k1::new();
111 /// # let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
112 /// # let (hop_node_id3, hop_node_id4) = (hop_node_id1, hop_node_id1);
113 /// # let destination_node_id = hop_node_id1;
114 /// # let node_id_lookup = EmptyNodeIdLookUp {};
115 /// # let message_router = Arc::new(FakeMessageRouter {});
116 /// # let custom_message_handler = IgnoringMessageHandler {};
117 /// # let offers_message_handler = IgnoringMessageHandler {};
118 /// // Create the onion messenger. This must use the same `keys_manager` as is passed to your
119 /// // ChannelManager.
120 /// let onion_messenger = OnionMessenger::new(
121 /// &keys_manager, &keys_manager, logger, &node_id_lookup, message_router,
122 /// &offers_message_handler, &custom_message_handler
125 /// # #[derive(Debug)]
126 /// # struct YourCustomMessage {}
127 /// impl Writeable for YourCustomMessage {
128 /// fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
130 /// // Write your custom onion message to `w`
133 /// impl OnionMessageContents for YourCustomMessage {
134 /// fn tlv_type(&self) -> u64 {
135 /// # let your_custom_message_type = 42;
136 /// your_custom_message_type
139 /// // Send a custom onion message to a node id.
140 /// let destination = Destination::Node(destination_node_id);
141 /// let reply_path = None;
142 /// # let message = YourCustomMessage {};
143 /// onion_messenger.send_onion_message(message, destination, reply_path);
145 /// // Create a blinded path to yourself, for someone to send an onion message to.
146 /// # let your_node_id = hop_node_id1;
147 /// let hops = [hop_node_id3, hop_node_id4, your_node_id];
148 /// let blinded_path = BlindedPath::new_for_message(&hops, &keys_manager, &secp_ctx).unwrap();
150 /// // Send a custom onion message to a blinded path.
151 /// let destination = Destination::BlindedPath(blinded_path);
152 /// let reply_path = None;
153 /// # let message = YourCustomMessage {};
154 /// onion_messenger.send_onion_message(message, destination, reply_path);
157 /// [`InvoiceRequest`]: crate::offers::invoice_request::InvoiceRequest
158 /// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
159 pub struct OnionMessenger<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, CMH: Deref>
161 ES::Target: EntropySource,
162 NS::Target: NodeSigner,
164 NL::Target: NodeIdLookUp,
165 MR::Target: MessageRouter,
166 OMH::Target: OffersMessageHandler,
167 CMH::Target: CustomOnionMessageHandler,
172 message_recipients: Mutex<HashMap<PublicKey, OnionMessageRecipient>>,
173 secp_ctx: Secp256k1<secp256k1::All>,
180 /// [`OnionMessage`]s buffered to be sent.
181 enum OnionMessageRecipient {
182 /// Messages for a node connected as a peer.
183 ConnectedPeer(VecDeque<OnionMessage>),
185 /// Messages for a node that is not yet connected, which are dropped after [`MAX_TIMER_TICKS`]
186 /// and tracked here.
187 PendingConnection(VecDeque<OnionMessage>, Option<Vec<SocketAddress>>, usize),
190 impl OnionMessageRecipient {
191 fn pending_connection(addresses: Vec<SocketAddress>) -> Self {
192 Self::PendingConnection(VecDeque::new(), Some(addresses), 0)
195 fn pending_messages(&self) -> &VecDeque<OnionMessage> {
197 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
198 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
202 fn enqueue_message(&mut self, message: OnionMessage) {
203 let pending_messages = match self {
204 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
205 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
208 pending_messages.push_back(message);
211 fn dequeue_message(&mut self) -> Option<OnionMessage> {
212 let pending_messages = match self {
213 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
214 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => {
215 debug_assert!(false);
220 pending_messages.pop_front()
224 fn release_pending_messages(&mut self) -> VecDeque<OnionMessage> {
225 let pending_messages = match self {
226 OnionMessageRecipient::ConnectedPeer(pending_messages) => pending_messages,
227 OnionMessageRecipient::PendingConnection(pending_messages, _, _) => pending_messages,
230 core::mem::take(pending_messages)
233 fn mark_connected(&mut self) {
234 if let OnionMessageRecipient::PendingConnection(pending_messages, _, _) = self {
235 let mut new_pending_messages = VecDeque::new();
236 core::mem::swap(pending_messages, &mut new_pending_messages);
237 *self = OnionMessageRecipient::ConnectedPeer(new_pending_messages);
241 fn is_connected(&self) -> bool {
243 OnionMessageRecipient::ConnectedPeer(..) => true,
244 OnionMessageRecipient::PendingConnection(..) => false,
250 /// The `Responder` struct creates an appropriate [`ResponseInstruction`]
251 /// for responding to a message.
252 pub struct Responder {
253 /// The path along which a response can be sent.
254 reply_path: BlindedPath,
255 path_id: Option<[u8; 32]>
259 /// Creates a new [`Responder`] instance with the provided reply path.
260 fn new(reply_path: BlindedPath, path_id: Option<[u8; 32]>) -> Self {
267 /// Creates the appropriate [`ResponseInstruction`] for a given response.
268 pub fn respond<T: OnionMessageContents>(self, response: T) -> ResponseInstruction<T> {
269 ResponseInstruction::WithoutReplyPath(OnionMessageResponse {
271 reply_path: self.reply_path,
272 path_id: self.path_id,
277 /// This struct contains the information needed to reply to a received message.
279 pub struct OnionMessageResponse<T: OnionMessageContents> {
281 reply_path: BlindedPath,
282 path_id: Option<[u8; 32]>,
285 /// `ResponseInstruction` represents instructions for responding to received messages.
286 pub enum ResponseInstruction<T: OnionMessageContents> {
287 /// Indicates that a response should be sent without including a reply path
288 /// for the recipient to respond back.
289 WithoutReplyPath(OnionMessageResponse<T>),
290 /// Indicates that there's no response to send back.
294 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
296 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
297 /// enqueued for sending.
298 #[cfg(not(c_bindings))]
299 pub struct PendingOnionMessage<T: OnionMessageContents> {
300 /// The message contents to send in an [`OnionMessage`].
303 /// The destination of the message.
304 pub destination: Destination,
306 /// A reply path to include in the [`OnionMessage`] for a response.
307 pub reply_path: Option<BlindedPath>,
311 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
313 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
314 /// enqueued for sending.
315 pub type PendingOnionMessage<T> = (T, Destination, Option<BlindedPath>);
317 pub(crate) fn new_pending_onion_message<T: OnionMessageContents>(
318 contents: T, destination: Destination, reply_path: Option<BlindedPath>
319 ) -> PendingOnionMessage<T> {
320 #[cfg(not(c_bindings))]
321 return PendingOnionMessage { contents, destination, reply_path };
323 return (contents, destination, reply_path);
326 /// A trait defining behavior for routing an [`OnionMessage`].
327 pub trait MessageRouter {
328 /// Returns a route for sending an [`OnionMessage`] to the given [`Destination`].
330 &self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
331 ) -> Result<OnionMessagePath, ()>;
333 /// Creates [`BlindedPath`]s to the `recipient` node. The nodes in `peers` are assumed to be
334 /// direct peers with the `recipient`.
335 fn create_blinded_paths<
336 T: secp256k1::Signing + secp256k1::Verification
338 &self, recipient: PublicKey, peers: Vec<PublicKey>, secp_ctx: &Secp256k1<T>,
339 ) -> Result<Vec<BlindedPath>, ()>;
342 /// A [`MessageRouter`] that can only route to a directly connected [`Destination`].
343 pub struct DefaultMessageRouter<G: Deref<Target=NetworkGraph<L>>, L: Deref, ES: Deref>
346 ES::Target: EntropySource,
352 impl<G: Deref<Target=NetworkGraph<L>>, L: Deref, ES: Deref> DefaultMessageRouter<G, L, ES>
355 ES::Target: EntropySource,
357 /// Creates a [`DefaultMessageRouter`] using the given [`NetworkGraph`].
358 pub fn new(network_graph: G, entropy_source: ES) -> Self {
359 Self { network_graph, entropy_source }
363 impl<G: Deref<Target=NetworkGraph<L>>, L: Deref, ES: Deref> MessageRouter for DefaultMessageRouter<G, L, ES>
366 ES::Target: EntropySource,
369 &self, sender: PublicKey, peers: Vec<PublicKey>, mut destination: Destination
370 ) -> Result<OnionMessagePath, ()> {
371 let network_graph = self.network_graph.deref().read_only();
372 destination.resolve(&network_graph);
374 let first_node = match destination.first_node() {
375 Some(first_node) => first_node,
376 None => return Err(()),
379 if peers.contains(&first_node) || sender == first_node {
380 Ok(OnionMessagePath {
381 intermediate_nodes: vec![], destination, first_node_addresses: None
384 let node_announcement = network_graph
385 .node(&NodeId::from_pubkey(&first_node))
386 .and_then(|node_info| node_info.announcement_info.as_ref())
387 .and_then(|announcement_info| announcement_info.announcement_message.as_ref())
388 .map(|node_announcement| &node_announcement.contents);
390 match node_announcement {
391 Some(node_announcement) if node_announcement.features.supports_onion_messages() => {
392 let first_node_addresses = Some(node_announcement.addresses.clone());
393 Ok(OnionMessagePath {
394 intermediate_nodes: vec![], destination, first_node_addresses
402 fn create_blinded_paths<
403 T: secp256k1::Signing + secp256k1::Verification
405 &self, recipient: PublicKey, peers: Vec<PublicKey>, secp_ctx: &Secp256k1<T>,
406 ) -> Result<Vec<BlindedPath>, ()> {
407 // Limit the number of blinded paths that are computed.
408 const MAX_PATHS: usize = 3;
410 // Ensure peers have at least three channels so that it is more difficult to infer the
411 // recipient's node_id.
412 const MIN_PEER_CHANNELS: usize = 3;
414 let network_graph = self.network_graph.deref().read_only();
415 let is_recipient_announced =
416 network_graph.nodes().contains_key(&NodeId::from_pubkey(&recipient));
418 let mut peer_info = peers.iter()
419 // Limit to peers with announced channels
422 .node(&NodeId::from_pubkey(pubkey))
423 .filter(|info| info.channels.len() >= MIN_PEER_CHANNELS)
424 .map(|info| (*pubkey, info.is_tor_only(), info.channels.len()))
426 // Exclude Tor-only nodes when the recipient is announced.
427 .filter(|(_, is_tor_only, _)| !(*is_tor_only && is_recipient_announced))
428 .collect::<Vec<_>>();
430 // Prefer using non-Tor nodes with the most channels as the introduction node.
431 peer_info.sort_unstable_by(|(_, a_tor_only, a_channels), (_, b_tor_only, b_channels)| {
432 a_tor_only.cmp(b_tor_only).then(a_channels.cmp(b_channels).reverse())
435 let paths = peer_info.into_iter()
436 .map(|(pubkey, _, _)| vec![pubkey, recipient])
437 .map(|node_pks| BlindedPath::new_for_message(&node_pks, &*self.entropy_source, secp_ctx))
439 .collect::<Result<Vec<_>, _>>();
442 Ok(paths) if !paths.is_empty() => Ok(paths),
444 if is_recipient_announced {
445 BlindedPath::one_hop_for_message(recipient, &*self.entropy_source, secp_ctx)
446 .map(|path| vec![path])
455 /// A path for sending an [`OnionMessage`].
457 pub struct OnionMessagePath {
458 /// Nodes on the path between the sender and the destination.
459 pub intermediate_nodes: Vec<PublicKey>,
461 /// The recipient of the message.
462 pub destination: Destination,
464 /// Addresses that may be used to connect to [`OnionMessagePath::first_node`].
466 /// Only needs to be set if a connection to the node is required. [`OnionMessenger`] may use
467 /// this to initiate such a connection.
468 pub first_node_addresses: Option<Vec<SocketAddress>>,
471 impl OnionMessagePath {
472 /// Returns the first node in the path.
473 pub fn first_node(&self) -> Option<PublicKey> {
474 self.intermediate_nodes
477 .or_else(|| self.destination.first_node())
481 /// The destination of an onion message.
482 #[derive(Clone, Hash, Debug, PartialEq, Eq)]
483 pub enum Destination {
484 /// We're sending this onion message to a node.
486 /// We're sending this onion message to a blinded path.
487 BlindedPath(BlindedPath),
491 /// Attempts to resolve the [`IntroductionNode::DirectedShortChannelId`] of a
492 /// [`Destination::BlindedPath`] to a [`IntroductionNode::NodeId`], if applicable, using the
493 /// provided [`ReadOnlyNetworkGraph`].
494 pub fn resolve(&mut self, network_graph: &ReadOnlyNetworkGraph) {
495 if let Destination::BlindedPath(path) = self {
496 if let IntroductionNode::DirectedShortChannelId(..) = path.introduction_node {
497 if let Some(pubkey) = path
498 .public_introduction_node_id(network_graph)
499 .and_then(|node_id| node_id.as_pubkey().ok())
501 path.introduction_node = IntroductionNode::NodeId(pubkey);
507 pub(super) fn num_hops(&self) -> usize {
509 Destination::Node(_) => 1,
510 Destination::BlindedPath(BlindedPath { blinded_hops, .. }) => blinded_hops.len(),
514 fn first_node(&self) -> Option<PublicKey> {
516 Destination::Node(node_id) => Some(*node_id),
517 Destination::BlindedPath(BlindedPath { introduction_node, .. }) => {
518 match introduction_node {
519 IntroductionNode::NodeId(pubkey) => Some(*pubkey),
520 IntroductionNode::DirectedShortChannelId(..) => None,
527 /// Result of successfully [sending an onion message].
529 /// [sending an onion message]: OnionMessenger::send_onion_message
530 #[derive(Clone, Hash, Debug, PartialEq, Eq)]
531 pub enum SendSuccess {
532 /// The message was buffered and will be sent once it is processed by
533 /// [`OnionMessageHandler::next_onion_message_for_peer`].
535 /// The message was buffered and will be sent once the node is connected as a peer and it is
536 /// processed by [`OnionMessageHandler::next_onion_message_for_peer`].
537 BufferedAwaitingConnection(PublicKey),
540 /// Errors that may occur when [sending an onion message].
542 /// [sending an onion message]: OnionMessenger::send_onion_message
543 #[derive(Clone, Hash, Debug, PartialEq, Eq)]
545 /// Errored computing onion message packet keys.
546 Secp256k1(secp256k1::Error),
547 /// Because implementations such as Eclair will drop onion messages where the message packet
548 /// exceeds 32834 bytes, we refuse to send messages where the packet exceeds this size.
550 /// The provided [`Destination`] was an invalid [`BlindedPath`] due to not having any blinded
553 /// The first hop is not a peer and doesn't have a known [`SocketAddress`].
554 InvalidFirstHop(PublicKey),
555 /// A path from the sender to the destination could not be found by the [`MessageRouter`].
557 /// Onion message contents must have a TLV type >= 64.
559 /// Our next-hop peer's buffer was full or our total outbound buffer was full.
561 /// Failed to retrieve our node id from the provided [`NodeSigner`].
563 /// [`NodeSigner`]: crate::sign::NodeSigner
565 /// The provided [`Destination`] has a blinded path with an unresolved introduction node. An
566 /// attempt to resolve it in the [`MessageRouter`] when finding an [`OnionMessagePath`] likely
568 UnresolvedIntroductionNode,
569 /// We attempted to send to a blinded path where we are the introduction node, and failed to
570 /// advance the blinded path to make the second hop the new introduction node. Either
571 /// [`NodeSigner::ecdh`] failed, we failed to tweak the current blinding point to get the
572 /// new blinding point, or we were attempting to send to ourselves.
573 BlindedPathAdvanceFailed,
576 /// Handler for custom onion messages. If you are using [`SimpleArcOnionMessenger`],
577 /// [`SimpleRefOnionMessenger`], or prefer to ignore inbound custom onion messages,
578 /// [`IgnoringMessageHandler`] must be provided to [`OnionMessenger::new`]. Otherwise, a custom
579 /// implementation of this trait must be provided, with [`CustomMessage`] specifying the supported
582 /// See [`OnionMessenger`] for example usage.
584 /// [`IgnoringMessageHandler`]: crate::ln::peer_handler::IgnoringMessageHandler
585 /// [`CustomMessage`]: Self::CustomMessage
586 pub trait CustomOnionMessageHandler {
587 /// The message known to the handler. To support multiple message types, you may want to make this
588 /// an enum with a variant for each supported message.
589 type CustomMessage: OnionMessageContents;
591 /// Called with the custom message that was received, returning a response to send, if any.
593 /// The returned [`Self::CustomMessage`], if any, is enqueued to be sent by [`OnionMessenger`].
594 fn handle_custom_message(&self, msg: Self::CustomMessage) -> Option<Self::CustomMessage>;
596 /// Read a custom message of type `message_type` from `buffer`, returning `Ok(None)` if the
597 /// message type is unknown.
598 fn read_custom_message<R: io::Read>(&self, message_type: u64, buffer: &mut R) -> Result<Option<Self::CustomMessage>, msgs::DecodeError>;
600 /// Releases any [`Self::CustomMessage`]s that need to be sent.
602 /// Typically, this is used for messages initiating a message flow rather than in response to
603 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
604 #[cfg(not(c_bindings))]
605 fn release_pending_custom_messages(&self) -> Vec<PendingOnionMessage<Self::CustomMessage>>;
607 /// Releases any [`Self::CustomMessage`]s that need to be sent.
609 /// Typically, this is used for messages initiating a message flow rather than in response to
610 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
612 fn release_pending_custom_messages(&self) -> Vec<(Self::CustomMessage, Destination, Option<BlindedPath>)>;
615 /// A processed incoming onion message, containing either a Forward (another onion message)
616 /// or a Receive payload with decrypted contents.
618 pub enum PeeledOnion<T: OnionMessageContents> {
619 /// Forwarded onion, with the next node id and a new onion
620 Forward(NextHop, OnionMessage),
621 /// Received onion message, with decrypted contents, path_id, and reply path
622 Receive(ParsedOnionMessageContents<T>, Option<[u8; 32]>, Option<BlindedPath>)
626 /// Creates an [`OnionMessage`] with the given `contents` for sending to the destination of
627 /// `path`, first calling [`Destination::resolve`] on `path.destination` with the given
628 /// [`ReadOnlyNetworkGraph`].
630 /// Returns the node id of the peer to send the message to, the message itself, and any addresses
631 /// needed to connect to the first node.
632 pub fn create_onion_message_resolving_destination<
633 ES: Deref, NS: Deref, NL: Deref, T: OnionMessageContents
635 entropy_source: &ES, node_signer: &NS, node_id_lookup: &NL,
636 network_graph: &ReadOnlyNetworkGraph, secp_ctx: &Secp256k1<secp256k1::All>,
637 mut path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
638 ) -> Result<(PublicKey, OnionMessage, Option<Vec<SocketAddress>>), SendError>
640 ES::Target: EntropySource,
641 NS::Target: NodeSigner,
642 NL::Target: NodeIdLookUp,
644 path.destination.resolve(network_graph);
645 create_onion_message(
646 entropy_source, node_signer, node_id_lookup, secp_ctx, path, contents, reply_path,
650 /// Creates an [`OnionMessage`] with the given `contents` for sending to the destination of
653 /// Returns the node id of the peer to send the message to, the message itself, and any addresses
654 /// needed to connect to the first node.
656 /// Returns [`SendError::UnresolvedIntroductionNode`] if:
657 /// - `destination` contains a blinded path with an [`IntroductionNode::DirectedShortChannelId`],
658 /// - unless it can be resolved by [`NodeIdLookUp::next_node_id`].
659 /// Use [`create_onion_message_resolving_destination`] instead to resolve the introduction node
660 /// first with a [`ReadOnlyNetworkGraph`].
661 pub fn create_onion_message<ES: Deref, NS: Deref, NL: Deref, T: OnionMessageContents>(
662 entropy_source: &ES, node_signer: &NS, node_id_lookup: &NL,
663 secp_ctx: &Secp256k1<secp256k1::All>, path: OnionMessagePath, contents: T,
664 reply_path: Option<BlindedPath>,
665 ) -> Result<(PublicKey, OnionMessage, Option<Vec<SocketAddress>>), SendError>
667 ES::Target: EntropySource,
668 NS::Target: NodeSigner,
669 NL::Target: NodeIdLookUp,
671 let OnionMessagePath { intermediate_nodes, mut destination, first_node_addresses } = path;
672 if let Destination::BlindedPath(BlindedPath { ref blinded_hops, .. }) = destination {
673 if blinded_hops.is_empty() {
674 return Err(SendError::TooFewBlindedHops);
678 if contents.tlv_type() < 64 { return Err(SendError::InvalidMessage) }
680 // If we are sending straight to a blinded path and we are the introduction node, we need to
681 // advance the blinded path by 1 hop so the second hop is the new introduction node.
682 if intermediate_nodes.len() == 0 {
683 if let Destination::BlindedPath(ref mut blinded_path) = destination {
684 let our_node_id = node_signer.get_node_id(Recipient::Node)
685 .map_err(|()| SendError::GetNodeIdFailed)?;
686 let introduction_node_id = match blinded_path.introduction_node {
687 IntroductionNode::NodeId(pubkey) => pubkey,
688 IntroductionNode::DirectedShortChannelId(direction, scid) => {
689 match node_id_lookup.next_node_id(scid) {
690 Some(next_node_id) => *direction.select_pubkey(&our_node_id, &next_node_id),
691 None => return Err(SendError::UnresolvedIntroductionNode),
695 if introduction_node_id == our_node_id {
696 advance_path_by_one(blinded_path, node_signer, node_id_lookup, &secp_ctx)
697 .map_err(|()| SendError::BlindedPathAdvanceFailed)?;
702 let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
703 let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
704 let (first_node_id, blinding_point) = if let Some(first_node_id) = intermediate_nodes.first() {
705 (*first_node_id, PublicKey::from_secret_key(&secp_ctx, &blinding_secret))
708 Destination::Node(pk) => (*pk, PublicKey::from_secret_key(&secp_ctx, &blinding_secret)),
709 Destination::BlindedPath(BlindedPath { introduction_node, blinding_point, .. }) => {
710 match introduction_node {
711 IntroductionNode::NodeId(pubkey) => (*pubkey, *blinding_point),
712 IntroductionNode::DirectedShortChannelId(..) => {
713 return Err(SendError::UnresolvedIntroductionNode);
719 let (packet_payloads, packet_keys) = packet_payloads_and_keys(
720 &secp_ctx, &intermediate_nodes, destination, contents, reply_path, &blinding_secret
723 let prng_seed = entropy_source.get_secure_random_bytes();
724 let onion_routing_packet = construct_onion_message_packet(
725 packet_payloads, packet_keys, prng_seed).map_err(|()| SendError::TooBigPacket)?;
727 let message = OnionMessage { blinding_point, onion_routing_packet };
728 Ok((first_node_id, message, first_node_addresses))
731 /// Decode one layer of an incoming [`OnionMessage`].
733 /// Returns either the next layer of the onion for forwarding or the decrypted content for the
735 pub fn peel_onion_message<NS: Deref, L: Deref, CMH: Deref>(
736 msg: &OnionMessage, secp_ctx: &Secp256k1<secp256k1::All>, node_signer: NS, logger: L,
738 ) -> Result<PeeledOnion<<<CMH>::Target as CustomOnionMessageHandler>::CustomMessage>, ()>
740 NS::Target: NodeSigner,
742 CMH::Target: CustomOnionMessageHandler,
744 let control_tlvs_ss = match node_signer.ecdh(Recipient::Node, &msg.blinding_point, None) {
747 log_error!(logger, "Failed to retrieve node secret: {:?}", e);
751 let onion_decode_ss = {
752 let blinding_factor = {
753 let mut hmac = HmacEngine::<Sha256>::new(b"blinded_node_id");
754 hmac.input(control_tlvs_ss.as_ref());
755 Hmac::from_engine(hmac).to_byte_array()
757 match node_signer.ecdh(Recipient::Node, &msg.onion_routing_packet.public_key,
758 Some(&Scalar::from_be_bytes(blinding_factor).unwrap()))
760 Ok(ss) => ss.secret_bytes(),
762 log_trace!(logger, "Failed to compute onion packet shared secret");
767 match onion_utils::decode_next_untagged_hop(
768 onion_decode_ss, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
769 (control_tlvs_ss, custom_handler.deref(), logger.deref())
771 Ok((Payload::Receive::<ParsedOnionMessageContents<<<CMH as Deref>::Target as CustomOnionMessageHandler>::CustomMessage>> {
772 message, control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id }), reply_path,
774 Ok(PeeledOnion::Receive(message, path_id, reply_path))
776 Ok((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
777 next_hop, next_blinding_override
778 })), Some((next_hop_hmac, new_packet_bytes)))) => {
779 // TODO: we need to check whether `next_hop` is our node, in which case this is a dummy
780 // blinded hop and this onion message is destined for us. In this situation, we should keep
781 // unwrapping the onion layers to get to the final payload. Since we don't have the option
782 // of creating blinded paths with dummy hops currently, we should be ok to not handle this
784 let new_pubkey = match onion_utils::next_hop_pubkey(&secp_ctx, msg.onion_routing_packet.public_key, &onion_decode_ss) {
787 log_trace!(logger, "Failed to compute next hop packet pubkey: {}", e);
791 let outgoing_packet = Packet {
793 public_key: new_pubkey,
794 hop_data: new_packet_bytes,
797 let onion_message = OnionMessage {
798 blinding_point: match next_blinding_override {
799 Some(blinding_point) => blinding_point,
801 match onion_utils::next_hop_pubkey(
802 &secp_ctx, msg.blinding_point, control_tlvs_ss.as_ref()
806 log_trace!(logger, "Failed to compute next blinding point: {}", e);
812 onion_routing_packet: outgoing_packet,
815 Ok(PeeledOnion::Forward(next_hop, onion_message))
818 log_trace!(logger, "Errored decoding onion message packet: {:?}", e);
822 log_trace!(logger, "Received bogus onion message packet, either the sender encoded a final hop as a forwarding hop or vice versa");
828 impl<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, CMH: Deref>
829 OnionMessenger<ES, NS, L, NL, MR, OMH, CMH>
831 ES::Target: EntropySource,
832 NS::Target: NodeSigner,
834 NL::Target: NodeIdLookUp,
835 MR::Target: MessageRouter,
836 OMH::Target: OffersMessageHandler,
837 CMH::Target: CustomOnionMessageHandler,
839 /// Constructs a new `OnionMessenger` to send, forward, and delegate received onion messages to
840 /// their respective handlers.
842 entropy_source: ES, node_signer: NS, logger: L, node_id_lookup: NL, message_router: MR,
843 offers_handler: OMH, custom_handler: CMH
845 let mut secp_ctx = Secp256k1::new();
846 secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
850 message_recipients: Mutex::new(new_hash_map()),
861 pub(crate) fn set_offers_handler(&mut self, offers_handler: OMH) {
862 self.offers_handler = offers_handler;
865 /// Sends an [`OnionMessage`] with the given `contents` to `destination`.
867 /// See [`OnionMessenger`] for example usage.
868 pub fn send_onion_message<T: OnionMessageContents>(
869 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>
870 ) -> Result<SendSuccess, SendError> {
871 self.find_path_and_enqueue_onion_message(
872 contents, destination, reply_path, format_args!("")
876 fn find_path_and_enqueue_onion_message<T: OnionMessageContents>(
877 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>,
878 log_suffix: fmt::Arguments
879 ) -> Result<SendSuccess, SendError> {
880 let mut logger = WithContext::from(&self.logger, None, None);
881 let result = self.find_path(destination)
883 let first_hop = path.intermediate_nodes.get(0).map(|p| *p);
884 logger = WithContext::from(&self.logger, first_hop, None);
885 self.enqueue_onion_message(path, contents, reply_path, log_suffix)
888 match result.as_ref() {
889 Err(SendError::GetNodeIdFailed) => {
890 log_warn!(logger, "Unable to retrieve node id {}", log_suffix);
892 Err(SendError::PathNotFound) => {
893 log_trace!(logger, "Failed to find path {}", log_suffix);
896 log_trace!(logger, "Failed sending onion message {}: {:?}", log_suffix, e);
898 Ok(SendSuccess::Buffered) => {
899 log_trace!(logger, "Buffered onion message {}", log_suffix);
901 Ok(SendSuccess::BufferedAwaitingConnection(node_id)) => {
904 "Buffered onion message waiting on peer connection {}: {}",
913 fn find_path(&self, destination: Destination) -> Result<OnionMessagePath, SendError> {
914 let sender = self.node_signer
915 .get_node_id(Recipient::Node)
916 .map_err(|_| SendError::GetNodeIdFailed)?;
918 let peers = self.message_recipients.lock().unwrap()
920 .filter(|(_, recipient)| matches!(recipient, OnionMessageRecipient::ConnectedPeer(_)))
921 .map(|(node_id, _)| *node_id)
925 .find_path(sender, peers, destination)
926 .map_err(|_| SendError::PathNotFound)
929 fn enqueue_onion_message<T: OnionMessageContents>(
930 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
931 log_suffix: fmt::Arguments
932 ) -> Result<SendSuccess, SendError> {
933 log_trace!(self.logger, "Constructing onion message {}: {:?}", log_suffix, contents);
935 let (first_node_id, onion_message, addresses) = create_onion_message(
936 &self.entropy_source, &self.node_signer, &self.node_id_lookup, &self.secp_ctx, path,
937 contents, reply_path,
940 let mut message_recipients = self.message_recipients.lock().unwrap();
941 if outbound_buffer_full(&first_node_id, &message_recipients) {
942 return Err(SendError::BufferFull);
945 match message_recipients.entry(first_node_id) {
946 hash_map::Entry::Vacant(e) => match addresses {
947 None => Err(SendError::InvalidFirstHop(first_node_id)),
949 e.insert(OnionMessageRecipient::pending_connection(addresses))
950 .enqueue_message(onion_message);
951 Ok(SendSuccess::BufferedAwaitingConnection(first_node_id))
954 hash_map::Entry::Occupied(mut e) => {
955 e.get_mut().enqueue_message(onion_message);
956 if e.get().is_connected() {
957 Ok(SendSuccess::Buffered)
959 Ok(SendSuccess::BufferedAwaitingConnection(first_node_id))
965 #[cfg(any(test, feature = "_test_utils"))]
966 pub fn send_onion_message_using_path<T: OnionMessageContents>(
967 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>
968 ) -> Result<SendSuccess, SendError> {
969 self.enqueue_onion_message(path, contents, reply_path, format_args!(""))
972 pub(crate) fn peel_onion_message(
973 &self, msg: &OnionMessage
974 ) -> Result<PeeledOnion<<<CMH>::Target as CustomOnionMessageHandler>::CustomMessage>, ()> {
976 msg, &self.secp_ctx, &*self.node_signer, &*self.logger, &*self.custom_handler
980 fn handle_onion_message_response<T: OnionMessageContents>(
981 &self, response: Option<T>, reply_path: Option<BlindedPath>, log_suffix: fmt::Arguments
983 if let Some(response) = response {
985 Some(reply_path) => {
986 let _ = self.find_path_and_enqueue_onion_message(
987 response, Destination::BlindedPath(reply_path), None, log_suffix
991 log_trace!(self.logger, "Missing reply path {}", log_suffix);
998 pub(super) fn release_pending_msgs(&self) -> HashMap<PublicKey, VecDeque<OnionMessage>> {
999 let mut message_recipients = self.message_recipients.lock().unwrap();
1000 let mut msgs = new_hash_map();
1001 // We don't want to disconnect the peers by removing them entirely from the original map, so we
1002 // release the pending message buffers individually.
1003 for (node_id, recipient) in &mut *message_recipients {
1004 msgs.insert(*node_id, recipient.release_pending_messages());
1010 fn outbound_buffer_full(peer_node_id: &PublicKey, buffer: &HashMap<PublicKey, OnionMessageRecipient>) -> bool {
1011 const MAX_TOTAL_BUFFER_SIZE: usize = (1 << 20) * 128;
1012 const MAX_PER_PEER_BUFFER_SIZE: usize = (1 << 10) * 256;
1013 let mut total_buffered_bytes = 0;
1014 let mut peer_buffered_bytes = 0;
1015 for (pk, peer_buf) in buffer {
1016 for om in peer_buf.pending_messages() {
1017 let om_len = om.serialized_length();
1018 if pk == peer_node_id {
1019 peer_buffered_bytes += om_len;
1021 total_buffered_bytes += om_len;
1023 if total_buffered_bytes >= MAX_TOTAL_BUFFER_SIZE ||
1024 peer_buffered_bytes >= MAX_PER_PEER_BUFFER_SIZE
1033 impl<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, CMH: Deref> EventsProvider
1034 for OnionMessenger<ES, NS, L, NL, MR, OMH, CMH>
1036 ES::Target: EntropySource,
1037 NS::Target: NodeSigner,
1039 NL::Target: NodeIdLookUp,
1040 MR::Target: MessageRouter,
1041 OMH::Target: OffersMessageHandler,
1042 CMH::Target: CustomOnionMessageHandler,
1044 fn process_pending_events<H: Deref>(&self, handler: H) where H::Target: EventHandler {
1045 for (node_id, recipient) in self.message_recipients.lock().unwrap().iter_mut() {
1046 if let OnionMessageRecipient::PendingConnection(_, addresses, _) = recipient {
1047 if let Some(addresses) = addresses.take() {
1048 handler.handle_event(Event::ConnectionNeeded { node_id: *node_id, addresses });
1055 impl<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, CMH: Deref> OnionMessageHandler
1056 for OnionMessenger<ES, NS, L, NL, MR, OMH, CMH>
1058 ES::Target: EntropySource,
1059 NS::Target: NodeSigner,
1061 NL::Target: NodeIdLookUp,
1062 MR::Target: MessageRouter,
1063 OMH::Target: OffersMessageHandler,
1064 CMH::Target: CustomOnionMessageHandler,
1066 fn handle_onion_message(&self, peer_node_id: &PublicKey, msg: &OnionMessage) {
1067 let logger = WithContext::from(&self.logger, Some(*peer_node_id), None);
1068 match self.peel_onion_message(msg) {
1069 Ok(PeeledOnion::Receive(message, path_id, reply_path)) => {
1072 "Received an onion message with path_id {:02x?} and {} reply_path: {:?}",
1073 path_id, if reply_path.is_some() { "a" } else { "no" }, message);
1076 ParsedOnionMessageContents::Offers(msg) => {
1077 let response = self.offers_handler.handle_message(msg);
1078 self.handle_onion_message_response(
1079 response, reply_path, format_args!(
1080 "when responding to Offers onion message with path_id {:02x?}",
1085 ParsedOnionMessageContents::Custom(msg) => {
1086 let response = self.custom_handler.handle_custom_message(msg);
1087 self.handle_onion_message_response(
1088 response, reply_path, format_args!(
1089 "when responding to Custom onion message with path_id {:02x?}",
1096 Ok(PeeledOnion::Forward(next_hop, onion_message)) => {
1097 let next_node_id = match next_hop {
1098 NextHop::NodeId(pubkey) => pubkey,
1099 NextHop::ShortChannelId(scid) => match self.node_id_lookup.next_node_id(scid) {
1100 Some(pubkey) => pubkey,
1102 log_trace!(self.logger, "Dropping forwarded onion messager: unable to resolve next hop using SCID {}", scid);
1108 let mut message_recipients = self.message_recipients.lock().unwrap();
1109 if outbound_buffer_full(&next_node_id, &message_recipients) {
1112 "Dropping forwarded onion message to peer {}: outbound buffer full",
1119 .entry(next_node_id)
1120 .or_insert_with(|| OnionMessageRecipient::ConnectedPeer(VecDeque::new()));
1122 match message_recipients.entry(next_node_id) {
1123 hash_map::Entry::Occupied(mut e) if matches!(
1124 e.get(), OnionMessageRecipient::ConnectedPeer(..)
1126 e.get_mut().enqueue_message(onion_message);
1127 log_trace!(logger, "Forwarding an onion message to peer {}", next_node_id);
1132 "Dropping forwarded onion message to disconnected peer {}",
1139 log_error!(logger, "Failed to process onion message {:?}", e);
1144 fn peer_connected(&self, their_node_id: &PublicKey, init: &msgs::Init, _inbound: bool) -> Result<(), ()> {
1145 if init.features.supports_onion_messages() {
1146 self.message_recipients.lock().unwrap()
1147 .entry(*their_node_id)
1148 .or_insert_with(|| OnionMessageRecipient::ConnectedPeer(VecDeque::new()))
1151 self.message_recipients.lock().unwrap().remove(their_node_id);
1157 fn peer_disconnected(&self, their_node_id: &PublicKey) {
1158 match self.message_recipients.lock().unwrap().remove(their_node_id) {
1159 Some(OnionMessageRecipient::ConnectedPeer(..)) => {},
1160 Some(_) => debug_assert!(false),
1165 fn timer_tick_occurred(&self) {
1166 let mut message_recipients = self.message_recipients.lock().unwrap();
1168 // Drop any pending recipients since the last call to avoid retaining buffered messages for
1170 message_recipients.retain(|_, recipient| match recipient {
1171 OnionMessageRecipient::PendingConnection(_, None, ticks) => *ticks < MAX_TIMER_TICKS,
1172 OnionMessageRecipient::PendingConnection(_, Some(_), _) => true,
1176 // Increment a timer tick for pending recipients so that their buffered messages are dropped
1177 // at MAX_TIMER_TICKS.
1178 for recipient in message_recipients.values_mut() {
1179 if let OnionMessageRecipient::PendingConnection(_, None, ticks) = recipient {
1185 fn provided_node_features(&self) -> NodeFeatures {
1186 let mut features = NodeFeatures::empty();
1187 features.set_onion_messages_optional();
1191 fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
1192 let mut features = InitFeatures::empty();
1193 features.set_onion_messages_optional();
1197 // Before returning any messages to send for the peer, this method will see if any messages were
1198 // enqueued in the handler by users, find a path to the corresponding blinded path's introduction
1199 // node, and then enqueue the message for sending to the first peer in the full path.
1200 fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<OnionMessage> {
1201 // Enqueue any initiating `OffersMessage`s to send.
1202 for message in self.offers_handler.release_pending_messages() {
1203 #[cfg(not(c_bindings))]
1204 let PendingOnionMessage { contents, destination, reply_path } = message;
1206 let (contents, destination, reply_path) = message;
1207 let _ = self.find_path_and_enqueue_onion_message(
1208 contents, destination, reply_path, format_args!("when sending OffersMessage")
1212 // Enqueue any initiating `CustomMessage`s to send.
1213 for message in self.custom_handler.release_pending_custom_messages() {
1214 #[cfg(not(c_bindings))]
1215 let PendingOnionMessage { contents, destination, reply_path } = message;
1217 let (contents, destination, reply_path) = message;
1218 let _ = self.find_path_and_enqueue_onion_message(
1219 contents, destination, reply_path, format_args!("when sending CustomMessage")
1223 self.message_recipients.lock().unwrap()
1224 .get_mut(&peer_node_id)
1225 .and_then(|buffer| buffer.dequeue_message())
1229 // TODO: parameterize the below Simple* types with OnionMessenger and handle the messages it
1231 /// Useful for simplifying the parameters of [`SimpleArcChannelManager`] and
1232 /// [`SimpleArcPeerManager`]. See their docs for more details.
1234 /// This is not exported to bindings users as type aliases aren't supported in most languages.
1236 /// [`SimpleArcChannelManager`]: crate::ln::channelmanager::SimpleArcChannelManager
1237 /// [`SimpleArcPeerManager`]: crate::ln::peer_handler::SimpleArcPeerManager
1238 #[cfg(not(c_bindings))]
1239 pub type SimpleArcOnionMessenger<M, T, F, L> = OnionMessenger<
1243 Arc<SimpleArcChannelManager<M, T, F, L>>,
1244 Arc<DefaultMessageRouter<Arc<NetworkGraph<Arc<L>>>, Arc<L>, Arc<KeysManager>>>,
1245 Arc<SimpleArcChannelManager<M, T, F, L>>,
1246 IgnoringMessageHandler
1249 /// Useful for simplifying the parameters of [`SimpleRefChannelManager`] and
1250 /// [`SimpleRefPeerManager`]. See their docs for more details.
1252 /// This is not exported to bindings users as type aliases aren't supported in most languages.
1254 /// [`SimpleRefChannelManager`]: crate::ln::channelmanager::SimpleRefChannelManager
1255 /// [`SimpleRefPeerManager`]: crate::ln::peer_handler::SimpleRefPeerManager
1256 #[cfg(not(c_bindings))]
1257 pub type SimpleRefOnionMessenger<
1258 'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, 'i, 'j, M, T, F, L
1263 &'i SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, M, T, F, L>,
1264 &'j DefaultMessageRouter<&'g NetworkGraph<&'b L>, &'b L, &'a KeysManager>,
1265 &'i SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, M, T, F, L>,
1266 IgnoringMessageHandler
1269 /// Construct onion packet payloads and keys for sending an onion message along the given
1270 /// `unblinded_path` to the given `destination`.
1271 fn packet_payloads_and_keys<T: OnionMessageContents, S: secp256k1::Signing + secp256k1::Verification>(
1272 secp_ctx: &Secp256k1<S>, unblinded_path: &[PublicKey], destination: Destination, message: T,
1273 mut reply_path: Option<BlindedPath>, session_priv: &SecretKey
1274 ) -> Result<(Vec<(Payload<T>, [u8; 32])>, Vec<onion_utils::OnionKeys>), SendError> {
1275 let num_hops = unblinded_path.len() + destination.num_hops();
1276 let mut payloads = Vec::with_capacity(num_hops);
1277 let mut onion_packet_keys = Vec::with_capacity(num_hops);
1279 let (mut intro_node_id_blinding_pt, num_blinded_hops) = match &destination {
1280 Destination::Node(_) => (None, 0),
1281 Destination::BlindedPath(BlindedPath { introduction_node, blinding_point, blinded_hops }) => {
1282 let introduction_node_id = match introduction_node {
1283 IntroductionNode::NodeId(pubkey) => pubkey,
1284 IntroductionNode::DirectedShortChannelId(..) => {
1285 return Err(SendError::UnresolvedIntroductionNode);
1288 (Some((*introduction_node_id, *blinding_point)), blinded_hops.len())
1291 let num_unblinded_hops = num_hops - num_blinded_hops;
1293 let mut unblinded_path_idx = 0;
1294 let mut blinded_path_idx = 0;
1295 let mut prev_control_tlvs_ss = None;
1296 let mut final_control_tlvs = None;
1297 utils::construct_keys_callback(secp_ctx, unblinded_path.iter(), Some(destination), session_priv,
1298 |_, onion_packet_ss, ephemeral_pubkey, control_tlvs_ss, unblinded_pk_opt, enc_payload_opt| {
1299 if num_unblinded_hops != 0 && unblinded_path_idx < num_unblinded_hops {
1300 if let Some(ss) = prev_control_tlvs_ss.take() {
1301 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(
1303 next_hop: NextHop::NodeId(unblinded_pk_opt.unwrap()),
1304 next_blinding_override: None,
1308 prev_control_tlvs_ss = Some(control_tlvs_ss);
1309 unblinded_path_idx += 1;
1310 } else if let Some((intro_node_id, blinding_pt)) = intro_node_id_blinding_pt.take() {
1311 if let Some(control_tlvs_ss) = prev_control_tlvs_ss.take() {
1312 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
1313 next_hop: NextHop::NodeId(intro_node_id),
1314 next_blinding_override: Some(blinding_pt),
1315 })), control_tlvs_ss));
1318 if blinded_path_idx < num_blinded_hops.saturating_sub(1) && enc_payload_opt.is_some() {
1319 payloads.push((Payload::Forward(ForwardControlTlvs::Blinded(enc_payload_opt.unwrap())),
1321 blinded_path_idx += 1;
1322 } else if let Some(encrypted_payload) = enc_payload_opt {
1323 final_control_tlvs = Some(ReceiveControlTlvs::Blinded(encrypted_payload));
1324 prev_control_tlvs_ss = Some(control_tlvs_ss);
1327 let (rho, mu) = onion_utils::gen_rho_mu_from_shared_secret(onion_packet_ss.as_ref());
1328 onion_packet_keys.push(onion_utils::OnionKeys {
1330 shared_secret: onion_packet_ss,
1332 blinding_factor: [0; 32],
1338 ).map_err(|e| SendError::Secp256k1(e))?;
1340 if let Some(control_tlvs) = final_control_tlvs {
1341 payloads.push((Payload::Receive {
1343 reply_path: reply_path.take(),
1345 }, prev_control_tlvs_ss.unwrap()));
1347 payloads.push((Payload::Receive {
1348 control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id: None, }),
1349 reply_path: reply_path.take(),
1351 }, prev_control_tlvs_ss.unwrap()));
1354 Ok((payloads, onion_packet_keys))
1357 /// Errors if the serialized payload size exceeds onion_message::BIG_PACKET_HOP_DATA_LEN
1358 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, ()> {
1360 // "`len` allows larger messages to be sent than the standard 1300 bytes allowed for an HTLC
1361 // onion, but this should be used sparingly as it is reduces anonymity set, hence the
1362 // recommendation that it either look like an HTLC onion, or if larger, be a fixed size."
1363 let payloads_ser_len = onion_utils::payloads_serialized_length(&payloads);
1364 let hop_data_len = if payloads_ser_len <= SMALL_PACKET_HOP_DATA_LEN {
1365 SMALL_PACKET_HOP_DATA_LEN
1366 } else if payloads_ser_len <= BIG_PACKET_HOP_DATA_LEN {
1367 BIG_PACKET_HOP_DATA_LEN
1368 } else { return Err(()) };
1370 onion_utils::construct_onion_message_packet::<_, _>(
1371 payloads, onion_keys, prng_seed, hop_data_len)