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,
249 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
251 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
252 /// enqueued for sending.
253 #[cfg(not(c_bindings))]
254 pub struct PendingOnionMessage<T: OnionMessageContents> {
255 /// The message contents to send in an [`OnionMessage`].
258 /// The destination of the message.
259 pub destination: Destination,
261 /// A reply path to include in the [`OnionMessage`] for a response.
262 pub reply_path: Option<BlindedPath>,
266 /// An [`OnionMessage`] for [`OnionMessenger`] to send.
268 /// These are obtained when released from [`OnionMessenger`]'s handlers after which they are
269 /// enqueued for sending.
270 pub type PendingOnionMessage<T> = (T, Destination, Option<BlindedPath>);
272 pub(crate) fn new_pending_onion_message<T: OnionMessageContents>(
273 contents: T, destination: Destination, reply_path: Option<BlindedPath>
274 ) -> PendingOnionMessage<T> {
275 #[cfg(not(c_bindings))]
276 return PendingOnionMessage { contents, destination, reply_path };
278 return (contents, destination, reply_path);
281 /// A trait defining behavior for routing an [`OnionMessage`].
282 pub trait MessageRouter {
283 /// Returns a route for sending an [`OnionMessage`] to the given [`Destination`].
285 &self, sender: PublicKey, peers: Vec<PublicKey>, destination: Destination
286 ) -> Result<OnionMessagePath, ()>;
288 /// Creates [`BlindedPath`]s to the `recipient` node. The nodes in `peers` are assumed to be
289 /// direct peers with the `recipient`.
290 fn create_blinded_paths<
291 T: secp256k1::Signing + secp256k1::Verification
293 &self, recipient: PublicKey, peers: Vec<PublicKey>, secp_ctx: &Secp256k1<T>,
294 ) -> Result<Vec<BlindedPath>, ()>;
297 /// A [`MessageRouter`] that can only route to a directly connected [`Destination`].
298 pub struct DefaultMessageRouter<G: Deref<Target=NetworkGraph<L>>, L: Deref, ES: Deref>
301 ES::Target: EntropySource,
307 impl<G: Deref<Target=NetworkGraph<L>>, L: Deref, ES: Deref> DefaultMessageRouter<G, L, ES>
310 ES::Target: EntropySource,
312 /// Creates a [`DefaultMessageRouter`] using the given [`NetworkGraph`].
313 pub fn new(network_graph: G, entropy_source: ES) -> Self {
314 Self { network_graph, entropy_source }
318 impl<G: Deref<Target=NetworkGraph<L>>, L: Deref, ES: Deref> MessageRouter for DefaultMessageRouter<G, L, ES>
321 ES::Target: EntropySource,
324 &self, sender: PublicKey, peers: Vec<PublicKey>, mut destination: Destination
325 ) -> Result<OnionMessagePath, ()> {
326 let network_graph = self.network_graph.deref().read_only();
327 destination.resolve(&network_graph);
329 let first_node = match destination.first_node() {
330 Some(first_node) => first_node,
331 None => return Err(()),
334 if peers.contains(&first_node) || sender == first_node {
335 Ok(OnionMessagePath {
336 intermediate_nodes: vec![], destination, first_node_addresses: None
339 let node_announcement = network_graph
340 .node(&NodeId::from_pubkey(&first_node))
341 .and_then(|node_info| node_info.announcement_info.as_ref())
342 .and_then(|announcement_info| announcement_info.announcement_message.as_ref())
343 .map(|node_announcement| &node_announcement.contents);
345 match node_announcement {
346 Some(node_announcement) if node_announcement.features.supports_onion_messages() => {
347 let first_node_addresses = Some(node_announcement.addresses.clone());
348 Ok(OnionMessagePath {
349 intermediate_nodes: vec![], destination, first_node_addresses
357 fn create_blinded_paths<
358 T: secp256k1::Signing + secp256k1::Verification
360 &self, recipient: PublicKey, peers: Vec<PublicKey>, secp_ctx: &Secp256k1<T>,
361 ) -> Result<Vec<BlindedPath>, ()> {
362 // Limit the number of blinded paths that are computed.
363 const MAX_PATHS: usize = 3;
365 // Ensure peers have at least three channels so that it is more difficult to infer the
366 // recipient's node_id.
367 const MIN_PEER_CHANNELS: usize = 3;
369 let network_graph = self.network_graph.deref().read_only();
370 let is_recipient_announced =
371 network_graph.nodes().contains_key(&NodeId::from_pubkey(&recipient));
373 let mut peer_info = peers.iter()
374 // Limit to peers with announced channels
377 .node(&NodeId::from_pubkey(pubkey))
378 .filter(|info| info.channels.len() >= MIN_PEER_CHANNELS)
379 .map(|info| (*pubkey, info.is_tor_only(), info.channels.len()))
381 // Exclude Tor-only nodes when the recipient is announced.
382 .filter(|(_, is_tor_only, _)| !(*is_tor_only && is_recipient_announced))
383 .collect::<Vec<_>>();
385 // Prefer using non-Tor nodes with the most channels as the introduction node.
386 peer_info.sort_unstable_by(|(_, a_tor_only, a_channels), (_, b_tor_only, b_channels)| {
387 a_tor_only.cmp(b_tor_only).then(a_channels.cmp(b_channels).reverse())
390 let paths = peer_info.into_iter()
391 .map(|(pubkey, _, _)| vec![pubkey, recipient])
392 .map(|node_pks| BlindedPath::new_for_message(&node_pks, &*self.entropy_source, secp_ctx))
394 .collect::<Result<Vec<_>, _>>();
397 Ok(paths) if !paths.is_empty() => Ok(paths),
399 if is_recipient_announced {
400 BlindedPath::one_hop_for_message(recipient, &*self.entropy_source, secp_ctx)
401 .map(|path| vec![path])
410 /// A path for sending an [`OnionMessage`].
412 pub struct OnionMessagePath {
413 /// Nodes on the path between the sender and the destination.
414 pub intermediate_nodes: Vec<PublicKey>,
416 /// The recipient of the message.
417 pub destination: Destination,
419 /// Addresses that may be used to connect to [`OnionMessagePath::first_node`].
421 /// Only needs to be set if a connection to the node is required. [`OnionMessenger`] may use
422 /// this to initiate such a connection.
423 pub first_node_addresses: Option<Vec<SocketAddress>>,
426 impl OnionMessagePath {
427 /// Returns the first node in the path.
428 pub fn first_node(&self) -> Option<PublicKey> {
429 self.intermediate_nodes
432 .or_else(|| self.destination.first_node())
436 /// The destination of an onion message.
437 #[derive(Clone, Hash, Debug, PartialEq, Eq)]
438 pub enum Destination {
439 /// We're sending this onion message to a node.
441 /// We're sending this onion message to a blinded path.
442 BlindedPath(BlindedPath),
446 /// Attempts to resolve the [`IntroductionNode::DirectedShortChannelId`] of a
447 /// [`Destination::BlindedPath`] to a [`IntroductionNode::NodeId`], if applicable, using the
448 /// provided [`ReadOnlyNetworkGraph`].
449 pub fn resolve(&mut self, network_graph: &ReadOnlyNetworkGraph) {
450 if let Destination::BlindedPath(path) = self {
451 if let IntroductionNode::DirectedShortChannelId(..) = path.introduction_node {
452 if let Some(pubkey) = path
453 .public_introduction_node_id(network_graph)
454 .and_then(|node_id| node_id.as_pubkey().ok())
456 path.introduction_node = IntroductionNode::NodeId(pubkey);
462 pub(super) fn num_hops(&self) -> usize {
464 Destination::Node(_) => 1,
465 Destination::BlindedPath(BlindedPath { blinded_hops, .. }) => blinded_hops.len(),
469 fn first_node(&self) -> Option<PublicKey> {
471 Destination::Node(node_id) => Some(*node_id),
472 Destination::BlindedPath(BlindedPath { introduction_node, .. }) => {
473 match introduction_node {
474 IntroductionNode::NodeId(pubkey) => Some(*pubkey),
475 IntroductionNode::DirectedShortChannelId(..) => None,
482 /// Result of successfully [sending an onion message].
484 /// [sending an onion message]: OnionMessenger::send_onion_message
485 #[derive(Clone, Hash, Debug, PartialEq, Eq)]
486 pub enum SendSuccess {
487 /// The message was buffered and will be sent once it is processed by
488 /// [`OnionMessageHandler::next_onion_message_for_peer`].
490 /// The message was buffered and will be sent once the node is connected as a peer and it is
491 /// processed by [`OnionMessageHandler::next_onion_message_for_peer`].
492 BufferedAwaitingConnection(PublicKey),
495 /// Errors that may occur when [sending an onion message].
497 /// [sending an onion message]: OnionMessenger::send_onion_message
498 #[derive(Clone, Hash, Debug, PartialEq, Eq)]
500 /// Errored computing onion message packet keys.
501 Secp256k1(secp256k1::Error),
502 /// Because implementations such as Eclair will drop onion messages where the message packet
503 /// exceeds 32834 bytes, we refuse to send messages where the packet exceeds this size.
505 /// The provided [`Destination`] was an invalid [`BlindedPath`] due to not having any blinded
508 /// The first hop is not a peer and doesn't have a known [`SocketAddress`].
509 InvalidFirstHop(PublicKey),
510 /// A path from the sender to the destination could not be found by the [`MessageRouter`].
512 /// Onion message contents must have a TLV type >= 64.
514 /// Our next-hop peer's buffer was full or our total outbound buffer was full.
516 /// Failed to retrieve our node id from the provided [`NodeSigner`].
518 /// [`NodeSigner`]: crate::sign::NodeSigner
520 /// The provided [`Destination`] has a blinded path with an unresolved introduction node. An
521 /// attempt to resolve it in the [`MessageRouter`] when finding an [`OnionMessagePath`] likely
523 UnresolvedIntroductionNode,
524 /// We attempted to send to a blinded path where we are the introduction node, and failed to
525 /// advance the blinded path to make the second hop the new introduction node. Either
526 /// [`NodeSigner::ecdh`] failed, we failed to tweak the current blinding point to get the
527 /// new blinding point, or we were attempting to send to ourselves.
528 BlindedPathAdvanceFailed,
531 /// Handler for custom onion messages. If you are using [`SimpleArcOnionMessenger`],
532 /// [`SimpleRefOnionMessenger`], or prefer to ignore inbound custom onion messages,
533 /// [`IgnoringMessageHandler`] must be provided to [`OnionMessenger::new`]. Otherwise, a custom
534 /// implementation of this trait must be provided, with [`CustomMessage`] specifying the supported
537 /// See [`OnionMessenger`] for example usage.
539 /// [`IgnoringMessageHandler`]: crate::ln::peer_handler::IgnoringMessageHandler
540 /// [`CustomMessage`]: Self::CustomMessage
541 pub trait CustomOnionMessageHandler {
542 /// The message known to the handler. To support multiple message types, you may want to make this
543 /// an enum with a variant for each supported message.
544 type CustomMessage: OnionMessageContents;
546 /// Called with the custom message that was received, returning a response to send, if any.
548 /// The returned [`Self::CustomMessage`], if any, is enqueued to be sent by [`OnionMessenger`].
549 fn handle_custom_message(&self, msg: Self::CustomMessage) -> Option<Self::CustomMessage>;
551 /// Read a custom message of type `message_type` from `buffer`, returning `Ok(None)` if the
552 /// message type is unknown.
553 fn read_custom_message<R: io::Read>(&self, message_type: u64, buffer: &mut R) -> Result<Option<Self::CustomMessage>, msgs::DecodeError>;
555 /// Releases any [`Self::CustomMessage`]s that need to be sent.
557 /// Typically, this is used for messages initiating a message flow rather than in response to
558 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
559 #[cfg(not(c_bindings))]
560 fn release_pending_custom_messages(&self) -> Vec<PendingOnionMessage<Self::CustomMessage>>;
562 /// Releases any [`Self::CustomMessage`]s that need to be sent.
564 /// Typically, this is used for messages initiating a message flow rather than in response to
565 /// another message. The latter should use the return value of [`Self::handle_custom_message`].
567 fn release_pending_custom_messages(&self) -> Vec<(Self::CustomMessage, Destination, Option<BlindedPath>)>;
570 /// A processed incoming onion message, containing either a Forward (another onion message)
571 /// or a Receive payload with decrypted contents.
573 pub enum PeeledOnion<T: OnionMessageContents> {
574 /// Forwarded onion, with the next node id and a new onion
575 Forward(NextHop, OnionMessage),
576 /// Received onion message, with decrypted contents, path_id, and reply path
577 Receive(ParsedOnionMessageContents<T>, Option<[u8; 32]>, Option<BlindedPath>)
581 /// Creates an [`OnionMessage`] with the given `contents` for sending to the destination of
582 /// `path`, first calling [`Destination::resolve`] on `path.destination` with the given
583 /// [`ReadOnlyNetworkGraph`].
585 /// Returns the node id of the peer to send the message to, the message itself, and any addresses
586 /// needed to connect to the first node.
587 pub fn create_onion_message_resolving_destination<
588 ES: Deref, NS: Deref, NL: Deref, T: OnionMessageContents
590 entropy_source: &ES, node_signer: &NS, node_id_lookup: &NL,
591 network_graph: &ReadOnlyNetworkGraph, secp_ctx: &Secp256k1<secp256k1::All>,
592 mut path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
593 ) -> Result<(PublicKey, OnionMessage, Option<Vec<SocketAddress>>), SendError>
595 ES::Target: EntropySource,
596 NS::Target: NodeSigner,
597 NL::Target: NodeIdLookUp,
599 path.destination.resolve(network_graph);
600 create_onion_message(
601 entropy_source, node_signer, node_id_lookup, secp_ctx, path, contents, reply_path,
605 /// Creates an [`OnionMessage`] with the given `contents` for sending to the destination of
608 /// Returns the node id of the peer to send the message to, the message itself, and any addresses
609 /// needed to connect to the first node.
611 /// Returns [`SendError::UnresolvedIntroductionNode`] if:
612 /// - `destination` contains a blinded path with an [`IntroductionNode::DirectedShortChannelId`],
613 /// - unless it can be resolved by [`NodeIdLookUp::next_node_id`].
614 /// Use [`create_onion_message_resolving_destination`] instead to resolve the introduction node
615 /// first with a [`ReadOnlyNetworkGraph`].
616 pub fn create_onion_message<ES: Deref, NS: Deref, NL: Deref, T: OnionMessageContents>(
617 entropy_source: &ES, node_signer: &NS, node_id_lookup: &NL,
618 secp_ctx: &Secp256k1<secp256k1::All>, path: OnionMessagePath, contents: T,
619 reply_path: Option<BlindedPath>,
620 ) -> Result<(PublicKey, OnionMessage, Option<Vec<SocketAddress>>), SendError>
622 ES::Target: EntropySource,
623 NS::Target: NodeSigner,
624 NL::Target: NodeIdLookUp,
626 let OnionMessagePath { intermediate_nodes, mut destination, first_node_addresses } = path;
627 if let Destination::BlindedPath(BlindedPath { ref blinded_hops, .. }) = destination {
628 if blinded_hops.is_empty() {
629 return Err(SendError::TooFewBlindedHops);
633 if contents.tlv_type() < 64 { return Err(SendError::InvalidMessage) }
635 // If we are sending straight to a blinded path and we are the introduction node, we need to
636 // advance the blinded path by 1 hop so the second hop is the new introduction node.
637 if intermediate_nodes.len() == 0 {
638 if let Destination::BlindedPath(ref mut blinded_path) = destination {
639 let our_node_id = node_signer.get_node_id(Recipient::Node)
640 .map_err(|()| SendError::GetNodeIdFailed)?;
641 let introduction_node_id = match blinded_path.introduction_node {
642 IntroductionNode::NodeId(pubkey) => pubkey,
643 IntroductionNode::DirectedShortChannelId(direction, scid) => {
644 match node_id_lookup.next_node_id(scid) {
645 Some(next_node_id) => *direction.select_pubkey(&our_node_id, &next_node_id),
646 None => return Err(SendError::UnresolvedIntroductionNode),
650 if introduction_node_id == our_node_id {
651 advance_path_by_one(blinded_path, node_signer, node_id_lookup, &secp_ctx)
652 .map_err(|()| SendError::BlindedPathAdvanceFailed)?;
657 let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
658 let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
659 let (first_node_id, blinding_point) = if let Some(first_node_id) = intermediate_nodes.first() {
660 (*first_node_id, PublicKey::from_secret_key(&secp_ctx, &blinding_secret))
663 Destination::Node(pk) => (*pk, PublicKey::from_secret_key(&secp_ctx, &blinding_secret)),
664 Destination::BlindedPath(BlindedPath { introduction_node, blinding_point, .. }) => {
665 match introduction_node {
666 IntroductionNode::NodeId(pubkey) => (*pubkey, *blinding_point),
667 IntroductionNode::DirectedShortChannelId(..) => {
668 return Err(SendError::UnresolvedIntroductionNode);
674 let (packet_payloads, packet_keys) = packet_payloads_and_keys(
675 &secp_ctx, &intermediate_nodes, destination, contents, reply_path, &blinding_secret
678 let prng_seed = entropy_source.get_secure_random_bytes();
679 let onion_routing_packet = construct_onion_message_packet(
680 packet_payloads, packet_keys, prng_seed).map_err(|()| SendError::TooBigPacket)?;
682 let message = OnionMessage { blinding_point, onion_routing_packet };
683 Ok((first_node_id, message, first_node_addresses))
686 /// Decode one layer of an incoming [`OnionMessage`].
688 /// Returns either the next layer of the onion for forwarding or the decrypted content for the
690 pub fn peel_onion_message<NS: Deref, L: Deref, CMH: Deref>(
691 msg: &OnionMessage, secp_ctx: &Secp256k1<secp256k1::All>, node_signer: NS, logger: L,
693 ) -> Result<PeeledOnion<<<CMH>::Target as CustomOnionMessageHandler>::CustomMessage>, ()>
695 NS::Target: NodeSigner,
697 CMH::Target: CustomOnionMessageHandler,
699 let control_tlvs_ss = match node_signer.ecdh(Recipient::Node, &msg.blinding_point, None) {
702 log_error!(logger, "Failed to retrieve node secret: {:?}", e);
706 let onion_decode_ss = {
707 let blinding_factor = {
708 let mut hmac = HmacEngine::<Sha256>::new(b"blinded_node_id");
709 hmac.input(control_tlvs_ss.as_ref());
710 Hmac::from_engine(hmac).to_byte_array()
712 match node_signer.ecdh(Recipient::Node, &msg.onion_routing_packet.public_key,
713 Some(&Scalar::from_be_bytes(blinding_factor).unwrap()))
715 Ok(ss) => ss.secret_bytes(),
717 log_trace!(logger, "Failed to compute onion packet shared secret");
722 match onion_utils::decode_next_untagged_hop(
723 onion_decode_ss, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
724 (control_tlvs_ss, custom_handler.deref(), logger.deref())
726 Ok((Payload::Receive::<ParsedOnionMessageContents<<<CMH as Deref>::Target as CustomOnionMessageHandler>::CustomMessage>> {
727 message, control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id }), reply_path,
729 Ok(PeeledOnion::Receive(message, path_id, reply_path))
731 Ok((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
732 next_hop, next_blinding_override
733 })), Some((next_hop_hmac, new_packet_bytes)))) => {
734 // TODO: we need to check whether `next_hop` is our node, in which case this is a dummy
735 // blinded hop and this onion message is destined for us. In this situation, we should keep
736 // unwrapping the onion layers to get to the final payload. Since we don't have the option
737 // of creating blinded paths with dummy hops currently, we should be ok to not handle this
739 let new_pubkey = match onion_utils::next_hop_pubkey(&secp_ctx, msg.onion_routing_packet.public_key, &onion_decode_ss) {
742 log_trace!(logger, "Failed to compute next hop packet pubkey: {}", e);
746 let outgoing_packet = Packet {
748 public_key: new_pubkey,
749 hop_data: new_packet_bytes,
752 let onion_message = OnionMessage {
753 blinding_point: match next_blinding_override {
754 Some(blinding_point) => blinding_point,
756 match onion_utils::next_hop_pubkey(
757 &secp_ctx, msg.blinding_point, control_tlvs_ss.as_ref()
761 log_trace!(logger, "Failed to compute next blinding point: {}", e);
767 onion_routing_packet: outgoing_packet,
770 Ok(PeeledOnion::Forward(next_hop, onion_message))
773 log_trace!(logger, "Errored decoding onion message packet: {:?}", e);
777 log_trace!(logger, "Received bogus onion message packet, either the sender encoded a final hop as a forwarding hop or vice versa");
783 impl<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, CMH: Deref>
784 OnionMessenger<ES, NS, L, NL, MR, OMH, CMH>
786 ES::Target: EntropySource,
787 NS::Target: NodeSigner,
789 NL::Target: NodeIdLookUp,
790 MR::Target: MessageRouter,
791 OMH::Target: OffersMessageHandler,
792 CMH::Target: CustomOnionMessageHandler,
794 /// Constructs a new `OnionMessenger` to send, forward, and delegate received onion messages to
795 /// their respective handlers.
797 entropy_source: ES, node_signer: NS, logger: L, node_id_lookup: NL, message_router: MR,
798 offers_handler: OMH, custom_handler: CMH
800 let mut secp_ctx = Secp256k1::new();
801 secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
805 message_recipients: Mutex::new(new_hash_map()),
816 pub(crate) fn set_offers_handler(&mut self, offers_handler: OMH) {
817 self.offers_handler = offers_handler;
820 /// Sends an [`OnionMessage`] with the given `contents` to `destination`.
822 /// See [`OnionMessenger`] for example usage.
823 pub fn send_onion_message<T: OnionMessageContents>(
824 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>
825 ) -> Result<SendSuccess, SendError> {
826 self.find_path_and_enqueue_onion_message(
827 contents, destination, reply_path, format_args!("")
831 fn find_path_and_enqueue_onion_message<T: OnionMessageContents>(
832 &self, contents: T, destination: Destination, reply_path: Option<BlindedPath>,
833 log_suffix: fmt::Arguments
834 ) -> Result<SendSuccess, SendError> {
835 let mut logger = WithContext::from(&self.logger, None, None);
836 let result = self.find_path(destination)
838 let first_hop = path.intermediate_nodes.get(0).map(|p| *p);
839 logger = WithContext::from(&self.logger, first_hop, None);
840 self.enqueue_onion_message(path, contents, reply_path, log_suffix)
843 match result.as_ref() {
844 Err(SendError::GetNodeIdFailed) => {
845 log_warn!(logger, "Unable to retrieve node id {}", log_suffix);
847 Err(SendError::PathNotFound) => {
848 log_trace!(logger, "Failed to find path {}", log_suffix);
851 log_trace!(logger, "Failed sending onion message {}: {:?}", log_suffix, e);
853 Ok(SendSuccess::Buffered) => {
854 log_trace!(logger, "Buffered onion message {}", log_suffix);
856 Ok(SendSuccess::BufferedAwaitingConnection(node_id)) => {
859 "Buffered onion message waiting on peer connection {}: {}",
868 fn find_path(&self, destination: Destination) -> Result<OnionMessagePath, SendError> {
869 let sender = self.node_signer
870 .get_node_id(Recipient::Node)
871 .map_err(|_| SendError::GetNodeIdFailed)?;
873 let peers = self.message_recipients.lock().unwrap()
875 .filter(|(_, recipient)| matches!(recipient, OnionMessageRecipient::ConnectedPeer(_)))
876 .map(|(node_id, _)| *node_id)
880 .find_path(sender, peers, destination)
881 .map_err(|_| SendError::PathNotFound)
884 fn enqueue_onion_message<T: OnionMessageContents>(
885 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>,
886 log_suffix: fmt::Arguments
887 ) -> Result<SendSuccess, SendError> {
888 log_trace!(self.logger, "Constructing onion message {}: {:?}", log_suffix, contents);
890 let (first_node_id, onion_message, addresses) = create_onion_message(
891 &self.entropy_source, &self.node_signer, &self.node_id_lookup, &self.secp_ctx, path,
892 contents, reply_path,
895 let mut message_recipients = self.message_recipients.lock().unwrap();
896 if outbound_buffer_full(&first_node_id, &message_recipients) {
897 return Err(SendError::BufferFull);
900 match message_recipients.entry(first_node_id) {
901 hash_map::Entry::Vacant(e) => match addresses {
902 None => Err(SendError::InvalidFirstHop(first_node_id)),
904 e.insert(OnionMessageRecipient::pending_connection(addresses))
905 .enqueue_message(onion_message);
906 Ok(SendSuccess::BufferedAwaitingConnection(first_node_id))
909 hash_map::Entry::Occupied(mut e) => {
910 e.get_mut().enqueue_message(onion_message);
911 if e.get().is_connected() {
912 Ok(SendSuccess::Buffered)
914 Ok(SendSuccess::BufferedAwaitingConnection(first_node_id))
920 #[cfg(any(test, feature = "_test_utils"))]
921 pub fn send_onion_message_using_path<T: OnionMessageContents>(
922 &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>
923 ) -> Result<SendSuccess, SendError> {
924 self.enqueue_onion_message(path, contents, reply_path, format_args!(""))
927 pub(crate) fn peel_onion_message(
928 &self, msg: &OnionMessage
929 ) -> Result<PeeledOnion<<<CMH>::Target as CustomOnionMessageHandler>::CustomMessage>, ()> {
931 msg, &self.secp_ctx, &*self.node_signer, &*self.logger, &*self.custom_handler
935 fn handle_onion_message_response<T: OnionMessageContents>(
936 &self, response: Option<T>, reply_path: Option<BlindedPath>, log_suffix: fmt::Arguments
938 if let Some(response) = response {
940 Some(reply_path) => {
941 let _ = self.find_path_and_enqueue_onion_message(
942 response, Destination::BlindedPath(reply_path), None, log_suffix
946 log_trace!(self.logger, "Missing reply path {}", log_suffix);
953 pub(super) fn release_pending_msgs(&self) -> HashMap<PublicKey, VecDeque<OnionMessage>> {
954 let mut message_recipients = self.message_recipients.lock().unwrap();
955 let mut msgs = new_hash_map();
956 // We don't want to disconnect the peers by removing them entirely from the original map, so we
957 // release the pending message buffers individually.
958 for (node_id, recipient) in &mut *message_recipients {
959 msgs.insert(*node_id, recipient.release_pending_messages());
965 fn outbound_buffer_full(peer_node_id: &PublicKey, buffer: &HashMap<PublicKey, OnionMessageRecipient>) -> bool {
966 const MAX_TOTAL_BUFFER_SIZE: usize = (1 << 20) * 128;
967 const MAX_PER_PEER_BUFFER_SIZE: usize = (1 << 10) * 256;
968 let mut total_buffered_bytes = 0;
969 let mut peer_buffered_bytes = 0;
970 for (pk, peer_buf) in buffer {
971 for om in peer_buf.pending_messages() {
972 let om_len = om.serialized_length();
973 if pk == peer_node_id {
974 peer_buffered_bytes += om_len;
976 total_buffered_bytes += om_len;
978 if total_buffered_bytes >= MAX_TOTAL_BUFFER_SIZE ||
979 peer_buffered_bytes >= MAX_PER_PEER_BUFFER_SIZE
988 impl<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, CMH: Deref> EventsProvider
989 for OnionMessenger<ES, NS, L, NL, MR, OMH, CMH>
991 ES::Target: EntropySource,
992 NS::Target: NodeSigner,
994 NL::Target: NodeIdLookUp,
995 MR::Target: MessageRouter,
996 OMH::Target: OffersMessageHandler,
997 CMH::Target: CustomOnionMessageHandler,
999 fn process_pending_events<H: Deref>(&self, handler: H) where H::Target: EventHandler {
1000 for (node_id, recipient) in self.message_recipients.lock().unwrap().iter_mut() {
1001 if let OnionMessageRecipient::PendingConnection(_, addresses, _) = recipient {
1002 if let Some(addresses) = addresses.take() {
1003 handler.handle_event(Event::ConnectionNeeded { node_id: *node_id, addresses });
1010 impl<ES: Deref, NS: Deref, L: Deref, NL: Deref, MR: Deref, OMH: Deref, CMH: Deref> OnionMessageHandler
1011 for OnionMessenger<ES, NS, L, NL, MR, OMH, CMH>
1013 ES::Target: EntropySource,
1014 NS::Target: NodeSigner,
1016 NL::Target: NodeIdLookUp,
1017 MR::Target: MessageRouter,
1018 OMH::Target: OffersMessageHandler,
1019 CMH::Target: CustomOnionMessageHandler,
1021 fn handle_onion_message(&self, peer_node_id: &PublicKey, msg: &OnionMessage) {
1022 let logger = WithContext::from(&self.logger, Some(*peer_node_id), None);
1023 match self.peel_onion_message(msg) {
1024 Ok(PeeledOnion::Receive(message, path_id, reply_path)) => {
1027 "Received an onion message with path_id {:02x?} and {} reply_path: {:?}",
1028 path_id, if reply_path.is_some() { "a" } else { "no" }, message);
1031 ParsedOnionMessageContents::Offers(msg) => {
1032 let response = self.offers_handler.handle_message(msg);
1033 self.handle_onion_message_response(
1034 response, reply_path, format_args!(
1035 "when responding to Offers onion message with path_id {:02x?}",
1040 ParsedOnionMessageContents::Custom(msg) => {
1041 let response = self.custom_handler.handle_custom_message(msg);
1042 self.handle_onion_message_response(
1043 response, reply_path, format_args!(
1044 "when responding to Custom onion message with path_id {:02x?}",
1051 Ok(PeeledOnion::Forward(next_hop, onion_message)) => {
1052 let next_node_id = match next_hop {
1053 NextHop::NodeId(pubkey) => pubkey,
1054 NextHop::ShortChannelId(scid) => match self.node_id_lookup.next_node_id(scid) {
1055 Some(pubkey) => pubkey,
1057 log_trace!(self.logger, "Dropping forwarded onion messager: unable to resolve next hop using SCID {}", scid);
1063 let mut message_recipients = self.message_recipients.lock().unwrap();
1064 if outbound_buffer_full(&next_node_id, &message_recipients) {
1067 "Dropping forwarded onion message to peer {}: outbound buffer full",
1074 .entry(next_node_id)
1075 .or_insert_with(|| OnionMessageRecipient::ConnectedPeer(VecDeque::new()));
1077 match message_recipients.entry(next_node_id) {
1078 hash_map::Entry::Occupied(mut e) if matches!(
1079 e.get(), OnionMessageRecipient::ConnectedPeer(..)
1081 e.get_mut().enqueue_message(onion_message);
1082 log_trace!(logger, "Forwarding an onion message to peer {}", next_node_id);
1087 "Dropping forwarded onion message to disconnected peer {}",
1094 log_error!(logger, "Failed to process onion message {:?}", e);
1099 fn peer_connected(&self, their_node_id: &PublicKey, init: &msgs::Init, _inbound: bool) -> Result<(), ()> {
1100 if init.features.supports_onion_messages() {
1101 self.message_recipients.lock().unwrap()
1102 .entry(*their_node_id)
1103 .or_insert_with(|| OnionMessageRecipient::ConnectedPeer(VecDeque::new()))
1106 self.message_recipients.lock().unwrap().remove(their_node_id);
1112 fn peer_disconnected(&self, their_node_id: &PublicKey) {
1113 match self.message_recipients.lock().unwrap().remove(their_node_id) {
1114 Some(OnionMessageRecipient::ConnectedPeer(..)) => {},
1115 Some(_) => debug_assert!(false),
1120 fn timer_tick_occurred(&self) {
1121 let mut message_recipients = self.message_recipients.lock().unwrap();
1123 // Drop any pending recipients since the last call to avoid retaining buffered messages for
1125 message_recipients.retain(|_, recipient| match recipient {
1126 OnionMessageRecipient::PendingConnection(_, None, ticks) => *ticks < MAX_TIMER_TICKS,
1127 OnionMessageRecipient::PendingConnection(_, Some(_), _) => true,
1131 // Increment a timer tick for pending recipients so that their buffered messages are dropped
1132 // at MAX_TIMER_TICKS.
1133 for recipient in message_recipients.values_mut() {
1134 if let OnionMessageRecipient::PendingConnection(_, None, ticks) = recipient {
1140 fn provided_node_features(&self) -> NodeFeatures {
1141 let mut features = NodeFeatures::empty();
1142 features.set_onion_messages_optional();
1146 fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
1147 let mut features = InitFeatures::empty();
1148 features.set_onion_messages_optional();
1152 // Before returning any messages to send for the peer, this method will see if any messages were
1153 // enqueued in the handler by users, find a path to the corresponding blinded path's introduction
1154 // node, and then enqueue the message for sending to the first peer in the full path.
1155 fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<OnionMessage> {
1156 // Enqueue any initiating `OffersMessage`s to send.
1157 for message in self.offers_handler.release_pending_messages() {
1158 #[cfg(not(c_bindings))]
1159 let PendingOnionMessage { contents, destination, reply_path } = message;
1161 let (contents, destination, reply_path) = message;
1162 let _ = self.find_path_and_enqueue_onion_message(
1163 contents, destination, reply_path, format_args!("when sending OffersMessage")
1167 // Enqueue any initiating `CustomMessage`s to send.
1168 for message in self.custom_handler.release_pending_custom_messages() {
1169 #[cfg(not(c_bindings))]
1170 let PendingOnionMessage { contents, destination, reply_path } = message;
1172 let (contents, destination, reply_path) = message;
1173 let _ = self.find_path_and_enqueue_onion_message(
1174 contents, destination, reply_path, format_args!("when sending CustomMessage")
1178 self.message_recipients.lock().unwrap()
1179 .get_mut(&peer_node_id)
1180 .and_then(|buffer| buffer.dequeue_message())
1184 // TODO: parameterize the below Simple* types with OnionMessenger and handle the messages it
1186 /// Useful for simplifying the parameters of [`SimpleArcChannelManager`] and
1187 /// [`SimpleArcPeerManager`]. See their docs for more details.
1189 /// This is not exported to bindings users as type aliases aren't supported in most languages.
1191 /// [`SimpleArcChannelManager`]: crate::ln::channelmanager::SimpleArcChannelManager
1192 /// [`SimpleArcPeerManager`]: crate::ln::peer_handler::SimpleArcPeerManager
1193 #[cfg(not(c_bindings))]
1194 pub type SimpleArcOnionMessenger<M, T, F, L> = OnionMessenger<
1198 Arc<SimpleArcChannelManager<M, T, F, L>>,
1199 Arc<DefaultMessageRouter<Arc<NetworkGraph<Arc<L>>>, Arc<L>, Arc<KeysManager>>>,
1200 Arc<SimpleArcChannelManager<M, T, F, L>>,
1201 IgnoringMessageHandler
1204 /// Useful for simplifying the parameters of [`SimpleRefChannelManager`] and
1205 /// [`SimpleRefPeerManager`]. See their docs for more details.
1207 /// This is not exported to bindings users as type aliases aren't supported in most languages.
1209 /// [`SimpleRefChannelManager`]: crate::ln::channelmanager::SimpleRefChannelManager
1210 /// [`SimpleRefPeerManager`]: crate::ln::peer_handler::SimpleRefPeerManager
1211 #[cfg(not(c_bindings))]
1212 pub type SimpleRefOnionMessenger<
1213 'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, 'i, 'j, M, T, F, L
1218 &'i SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, M, T, F, L>,
1219 &'j DefaultMessageRouter<&'g NetworkGraph<&'b L>, &'b L, &'a KeysManager>,
1220 &'i SimpleRefChannelManager<'a, 'b, 'c, 'd, 'e, 'f, 'g, 'h, M, T, F, L>,
1221 IgnoringMessageHandler
1224 /// Construct onion packet payloads and keys for sending an onion message along the given
1225 /// `unblinded_path` to the given `destination`.
1226 fn packet_payloads_and_keys<T: OnionMessageContents, S: secp256k1::Signing + secp256k1::Verification>(
1227 secp_ctx: &Secp256k1<S>, unblinded_path: &[PublicKey], destination: Destination, message: T,
1228 mut reply_path: Option<BlindedPath>, session_priv: &SecretKey
1229 ) -> Result<(Vec<(Payload<T>, [u8; 32])>, Vec<onion_utils::OnionKeys>), SendError> {
1230 let num_hops = unblinded_path.len() + destination.num_hops();
1231 let mut payloads = Vec::with_capacity(num_hops);
1232 let mut onion_packet_keys = Vec::with_capacity(num_hops);
1234 let (mut intro_node_id_blinding_pt, num_blinded_hops) = match &destination {
1235 Destination::Node(_) => (None, 0),
1236 Destination::BlindedPath(BlindedPath { introduction_node, blinding_point, blinded_hops }) => {
1237 let introduction_node_id = match introduction_node {
1238 IntroductionNode::NodeId(pubkey) => pubkey,
1239 IntroductionNode::DirectedShortChannelId(..) => {
1240 return Err(SendError::UnresolvedIntroductionNode);
1243 (Some((*introduction_node_id, *blinding_point)), blinded_hops.len())
1246 let num_unblinded_hops = num_hops - num_blinded_hops;
1248 let mut unblinded_path_idx = 0;
1249 let mut blinded_path_idx = 0;
1250 let mut prev_control_tlvs_ss = None;
1251 let mut final_control_tlvs = None;
1252 utils::construct_keys_callback(secp_ctx, unblinded_path.iter(), Some(destination), session_priv,
1253 |_, onion_packet_ss, ephemeral_pubkey, control_tlvs_ss, unblinded_pk_opt, enc_payload_opt| {
1254 if num_unblinded_hops != 0 && unblinded_path_idx < num_unblinded_hops {
1255 if let Some(ss) = prev_control_tlvs_ss.take() {
1256 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(
1258 next_hop: NextHop::NodeId(unblinded_pk_opt.unwrap()),
1259 next_blinding_override: None,
1263 prev_control_tlvs_ss = Some(control_tlvs_ss);
1264 unblinded_path_idx += 1;
1265 } else if let Some((intro_node_id, blinding_pt)) = intro_node_id_blinding_pt.take() {
1266 if let Some(control_tlvs_ss) = prev_control_tlvs_ss.take() {
1267 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
1268 next_hop: NextHop::NodeId(intro_node_id),
1269 next_blinding_override: Some(blinding_pt),
1270 })), control_tlvs_ss));
1273 if blinded_path_idx < num_blinded_hops.saturating_sub(1) && enc_payload_opt.is_some() {
1274 payloads.push((Payload::Forward(ForwardControlTlvs::Blinded(enc_payload_opt.unwrap())),
1276 blinded_path_idx += 1;
1277 } else if let Some(encrypted_payload) = enc_payload_opt {
1278 final_control_tlvs = Some(ReceiveControlTlvs::Blinded(encrypted_payload));
1279 prev_control_tlvs_ss = Some(control_tlvs_ss);
1282 let (rho, mu) = onion_utils::gen_rho_mu_from_shared_secret(onion_packet_ss.as_ref());
1283 onion_packet_keys.push(onion_utils::OnionKeys {
1285 shared_secret: onion_packet_ss,
1287 blinding_factor: [0; 32],
1293 ).map_err(|e| SendError::Secp256k1(e))?;
1295 if let Some(control_tlvs) = final_control_tlvs {
1296 payloads.push((Payload::Receive {
1298 reply_path: reply_path.take(),
1300 }, prev_control_tlvs_ss.unwrap()));
1302 payloads.push((Payload::Receive {
1303 control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id: None, }),
1304 reply_path: reply_path.take(),
1306 }, prev_control_tlvs_ss.unwrap()));
1309 Ok((payloads, onion_packet_keys))
1312 /// Errors if the serialized payload size exceeds onion_message::BIG_PACKET_HOP_DATA_LEN
1313 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, ()> {
1315 // "`len` allows larger messages to be sent than the standard 1300 bytes allowed for an HTLC
1316 // onion, but this should be used sparingly as it is reduces anonymity set, hence the
1317 // recommendation that it either look like an HTLC onion, or if larger, be a fixed size."
1318 let payloads_ser_len = onion_utils::payloads_serialized_length(&payloads);
1319 let hop_data_len = if payloads_ser_len <= SMALL_PACKET_HOP_DATA_LEN {
1320 SMALL_PACKET_HOP_DATA_LEN
1321 } else if payloads_ser_len <= BIG_PACKET_HOP_DATA_LEN {
1322 BIG_PACKET_HOP_DATA_LEN
1323 } else { return Err(()) };
1325 onion_utils::construct_onion_message_packet::<_, _>(
1326 payloads, onion_keys, prng_seed, hop_data_len)