1 // This file is Copyright its original authors, visible in version control
4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
7 // You may not use this file except in accordance with one or both of these
10 //! LDK sends, receives, and forwards onion messages via the [`OnionMessenger`]. See its docs for
13 use bitcoin::hashes::{Hash, HashEngine};
14 use bitcoin::hashes::hmac::{Hmac, HmacEngine};
15 use bitcoin::hashes::sha256::Hash as Sha256;
16 use bitcoin::secp256k1::{self, PublicKey, Scalar, Secp256k1, SecretKey};
18 use crate::chain::keysinterface::{EntropySource, KeysManager, NodeSigner, Recipient};
19 use crate::ln::features::{InitFeatures, NodeFeatures};
20 use crate::ln::msgs::{self, OnionMessageHandler};
21 use crate::ln::onion_utils;
22 use crate::ln::peer_handler::IgnoringMessageHandler;
23 use super::blinded_path::{BlindedPath, ForwardTlvs, ReceiveTlvs};
24 use super::packet::{CustomOnionMessageContents, OnionMessageContents};
25 use super::packet::{BIG_PACKET_HOP_DATA_LEN, ForwardControlTlvs, Packet, Payload, ReceiveControlTlvs, SMALL_PACKET_HOP_DATA_LEN};
27 use crate::util::events::OnionMessageProvider;
28 use crate::util::logger::Logger;
29 use crate::util::ser::Writeable;
33 use crate::sync::{Arc, Mutex};
34 use crate::prelude::*;
36 /// A sender, receiver and forwarder of onion messages. In upcoming releases, this object will be
37 /// used to retrieve invoices and fulfill invoice requests from [offers]. Currently, only sending
38 /// and receiving custom onion messages is supported.
43 /// # extern crate bitcoin;
44 /// # use bitcoin::hashes::_export::_core::time::Duration;
45 /// # use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey};
46 /// # use lightning::chain::keysinterface::KeysManager;
47 /// # use lightning::ln::peer_handler::IgnoringMessageHandler;
48 /// # use lightning::onion_message::blinded_path::BlindedPath;
49 /// # use lightning::onion_message::messenger::{Destination, OnionMessenger};
50 /// # use lightning::onion_message::packet::{CustomOnionMessageContents, OnionMessageContents};
51 /// # use lightning::util::logger::{Logger, Record};
52 /// # use lightning::util::ser::{Writeable, Writer};
53 /// # use lightning::io;
54 /// # use std::sync::Arc;
55 /// # struct FakeLogger;
56 /// # impl Logger for FakeLogger {
57 /// # fn log(&self, record: &Record) { unimplemented!() }
59 /// # let seed = [42u8; 32];
60 /// # let time = Duration::from_secs(123456);
61 /// # let keys_manager = KeysManager::new(&seed, time.as_secs(), time.subsec_nanos());
62 /// # let logger = Arc::new(FakeLogger {});
63 /// # let node_secret = SecretKey::from_slice(&hex::decode("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap();
64 /// # let secp_ctx = Secp256k1::new();
65 /// # let hop_node_id1 = PublicKey::from_secret_key(&secp_ctx, &node_secret);
66 /// # let (hop_node_id2, hop_node_id3, hop_node_id4) = (hop_node_id1, hop_node_id1, hop_node_id1);
67 /// # let destination_node_id = hop_node_id1;
68 /// # let your_custom_message_handler = IgnoringMessageHandler {};
69 /// // Create the onion messenger. This must use the same `keys_manager` as is passed to your
70 /// // ChannelManager.
71 /// let onion_messenger = OnionMessenger::new(&keys_manager, &keys_manager, logger, &your_custom_message_handler);
73 /// # #[derive(Clone)]
74 /// # struct YourCustomMessage {}
75 /// impl Writeable for YourCustomMessage {
76 /// fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
78 /// // Write your custom onion message to `w`
81 /// impl CustomOnionMessageContents for YourCustomMessage {
82 /// fn tlv_type(&self) -> u64 {
83 /// # let your_custom_message_type = 42;
84 /// your_custom_message_type
87 /// // Send a custom onion message to a node id.
88 /// let intermediate_hops = [hop_node_id1, hop_node_id2];
89 /// let reply_path = None;
90 /// # let your_custom_message = YourCustomMessage {};
91 /// let message = OnionMessageContents::Custom(your_custom_message);
92 /// onion_messenger.send_onion_message(&intermediate_hops, Destination::Node(destination_node_id), message, reply_path);
94 /// // Create a blinded path to yourself, for someone to send an onion message to.
95 /// # let your_node_id = hop_node_id1;
96 /// let hops = [hop_node_id3, hop_node_id4, your_node_id];
97 /// let blinded_path = BlindedPath::new(&hops, &keys_manager, &secp_ctx).unwrap();
99 /// // Send a custom onion message to a blinded path.
100 /// # let intermediate_hops = [hop_node_id1, hop_node_id2];
101 /// let reply_path = None;
102 /// # let your_custom_message = YourCustomMessage {};
103 /// let message = OnionMessageContents::Custom(your_custom_message);
104 /// onion_messenger.send_onion_message(&intermediate_hops, Destination::BlindedPath(blinded_path), message, reply_path);
107 /// [offers]: <https://github.com/lightning/bolts/pull/798>
108 /// [`OnionMessenger`]: crate::onion_message::OnionMessenger
109 pub struct OnionMessenger<ES: Deref, NS: Deref, L: Deref, CMH: Deref>
110 where ES::Target: EntropySource,
111 NS::Target: NodeSigner,
113 CMH:: Target: CustomOnionMessageHandler,
118 pending_messages: Mutex<HashMap<PublicKey, VecDeque<msgs::OnionMessage>>>,
119 secp_ctx: Secp256k1<secp256k1::All>,
122 // invoice_handler: InvoiceHandler,
125 /// The destination of an onion message.
126 pub enum Destination {
127 /// We're sending this onion message to a node.
129 /// We're sending this onion message to a blinded path.
130 BlindedPath(BlindedPath),
134 pub(super) fn num_hops(&self) -> usize {
136 Destination::Node(_) => 1,
137 Destination::BlindedPath(BlindedPath { blinded_hops, .. }) => blinded_hops.len(),
142 /// Errors that may occur when [sending an onion message].
144 /// [sending an onion message]: OnionMessenger::send_onion_message
145 #[derive(Debug, PartialEq, Eq)]
147 /// Errored computing onion message packet keys.
148 Secp256k1(secp256k1::Error),
149 /// Because implementations such as Eclair will drop onion messages where the message packet
150 /// exceeds 32834 bytes, we refuse to send messages where the packet exceeds this size.
152 /// The provided [`Destination`] was an invalid [`BlindedPath`], due to having fewer than two
155 /// Our next-hop peer was offline or does not support onion message forwarding.
157 /// Onion message contents must have a TLV type >= 64.
159 /// Our next-hop peer's buffer was full or our total outbound buffer was full.
161 /// Failed to retrieve our node id from the provided [`NodeSigner`].
163 /// [`NodeSigner`]: crate::chain::keysinterface::NodeSigner
165 /// We attempted to send to a blinded path where we are the introduction node, and failed to
166 /// advance the blinded path to make the second hop the new introduction node. Either
167 /// [`NodeSigner::ecdh`] failed, we failed to tweak the current blinding point to get the
168 /// new blinding point, or we were attempting to send to ourselves.
169 BlindedPathAdvanceFailed,
172 /// Handler for custom onion messages. If you are using [`SimpleArcOnionMessenger`],
173 /// [`SimpleRefOnionMessenger`], or prefer to ignore inbound custom onion messages,
174 /// [`IgnoringMessageHandler`] must be provided to [`OnionMessenger::new`]. Otherwise, a custom
175 /// implementation of this trait must be provided, with [`CustomMessage`] specifying the supported
178 /// See [`OnionMessenger`] for example usage.
180 /// [`IgnoringMessageHandler`]: crate::ln::peer_handler::IgnoringMessageHandler
181 /// [`CustomMessage`]: Self::CustomMessage
182 pub trait CustomOnionMessageHandler {
183 /// The message known to the handler. To support multiple message types, you may want to make this
184 /// an enum with a variant for each supported message.
185 type CustomMessage: CustomOnionMessageContents;
186 /// Called with the custom message that was received.
187 fn handle_custom_message(&self, msg: Self::CustomMessage);
188 /// Read a custom message of type `message_type` from `buffer`, returning `Ok(None)` if the
189 /// message type is unknown.
190 fn read_custom_message<R: io::Read>(&self, message_type: u64, buffer: &mut R) -> Result<Option<Self::CustomMessage>, msgs::DecodeError>;
193 impl<ES: Deref, NS: Deref, L: Deref, CMH: Deref> OnionMessenger<ES, NS, L, CMH>
194 where ES::Target: EntropySource,
195 NS::Target: NodeSigner,
197 CMH::Target: CustomOnionMessageHandler,
199 /// Constructs a new `OnionMessenger` to send, forward, and delegate received onion messages to
200 /// their respective handlers.
201 pub fn new(entropy_source: ES, node_signer: NS, logger: L, custom_handler: CMH) -> Self {
202 let mut secp_ctx = Secp256k1::new();
203 secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
207 pending_messages: Mutex::new(HashMap::new()),
214 /// Send an onion message with contents `message` to `destination`, routing it through `intermediate_nodes`.
215 /// See [`OnionMessenger`] for example usage.
216 pub fn send_onion_message<T: CustomOnionMessageContents>(&self, intermediate_nodes: &[PublicKey], mut destination: Destination, message: OnionMessageContents<T>, reply_path: Option<BlindedPath>) -> Result<(), SendError> {
217 if let Destination::BlindedPath(BlindedPath { ref blinded_hops, .. }) = destination {
218 if blinded_hops.len() < 2 {
219 return Err(SendError::TooFewBlindedHops);
222 let OnionMessageContents::Custom(ref msg) = message;
223 if msg.tlv_type() < 64 { return Err(SendError::InvalidMessage) }
225 // If we are sending straight to a blinded path and we are the introduction node, we need to
226 // advance the blinded path by 1 hop so the second hop is the new introduction node.
227 if intermediate_nodes.len() == 0 {
228 if let Destination::BlindedPath(ref mut blinded_path) = destination {
229 let our_node_id = self.node_signer.get_node_id(Recipient::Node)
230 .map_err(|()| SendError::GetNodeIdFailed)?;
231 if blinded_path.introduction_node_id == our_node_id {
232 blinded_path.advance_by_one(&self.node_signer, &self.secp_ctx)
233 .map_err(|()| SendError::BlindedPathAdvanceFailed)?;
238 let blinding_secret_bytes = self.entropy_source.get_secure_random_bytes();
239 let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
240 let (introduction_node_id, blinding_point) = if intermediate_nodes.len() != 0 {
241 (intermediate_nodes[0], PublicKey::from_secret_key(&self.secp_ctx, &blinding_secret))
244 Destination::Node(pk) => (pk, PublicKey::from_secret_key(&self.secp_ctx, &blinding_secret)),
245 Destination::BlindedPath(BlindedPath { introduction_node_id, blinding_point, .. }) =>
246 (introduction_node_id, blinding_point),
249 let (packet_payloads, packet_keys) = packet_payloads_and_keys(
250 &self.secp_ctx, intermediate_nodes, destination, message, reply_path, &blinding_secret)
251 .map_err(|e| SendError::Secp256k1(e))?;
253 let prng_seed = self.entropy_source.get_secure_random_bytes();
254 let onion_routing_packet = construct_onion_message_packet(
255 packet_payloads, packet_keys, prng_seed).map_err(|()| SendError::TooBigPacket)?;
257 let mut pending_per_peer_msgs = self.pending_messages.lock().unwrap();
258 if outbound_buffer_full(&introduction_node_id, &pending_per_peer_msgs) { return Err(SendError::BufferFull) }
259 match pending_per_peer_msgs.entry(introduction_node_id) {
260 hash_map::Entry::Vacant(_) => Err(SendError::InvalidFirstHop),
261 hash_map::Entry::Occupied(mut e) => {
262 e.get_mut().push_back(msgs::OnionMessage { blinding_point, onion_routing_packet });
269 pub(super) fn release_pending_msgs(&self) -> HashMap<PublicKey, VecDeque<msgs::OnionMessage>> {
270 let mut pending_msgs = self.pending_messages.lock().unwrap();
271 let mut msgs = HashMap::new();
272 // We don't want to disconnect the peers by removing them entirely from the original map, so we
273 // swap the pending message buffers individually.
274 for (peer_node_id, pending_messages) in &mut *pending_msgs {
275 msgs.insert(*peer_node_id, core::mem::take(pending_messages));
281 fn outbound_buffer_full(peer_node_id: &PublicKey, buffer: &HashMap<PublicKey, VecDeque<msgs::OnionMessage>>) -> bool {
282 const MAX_TOTAL_BUFFER_SIZE: usize = (1 << 20) * 128;
283 const MAX_PER_PEER_BUFFER_SIZE: usize = (1 << 10) * 256;
284 let mut total_buffered_bytes = 0;
285 let mut peer_buffered_bytes = 0;
286 for (pk, peer_buf) in buffer {
288 let om_len = om.serialized_length();
289 if pk == peer_node_id {
290 peer_buffered_bytes += om_len;
292 total_buffered_bytes += om_len;
294 if total_buffered_bytes >= MAX_TOTAL_BUFFER_SIZE ||
295 peer_buffered_bytes >= MAX_PER_PEER_BUFFER_SIZE
304 impl<ES: Deref, NS: Deref, L: Deref, CMH: Deref> OnionMessageHandler for OnionMessenger<ES, NS, L, CMH>
305 where ES::Target: EntropySource,
306 NS::Target: NodeSigner,
308 CMH::Target: CustomOnionMessageHandler + Sized,
310 /// Handle an incoming onion message. Currently, if a message was destined for us we will log, but
311 /// soon we'll delegate the onion message to a handler that can generate invoices or send
313 fn handle_onion_message(&self, _peer_node_id: &PublicKey, msg: &msgs::OnionMessage) {
314 let control_tlvs_ss = match self.node_signer.ecdh(Recipient::Node, &msg.blinding_point, None) {
317 log_error!(self.logger, "Failed to retrieve node secret: {:?}", e);
321 let onion_decode_ss = {
322 let blinding_factor = {
323 let mut hmac = HmacEngine::<Sha256>::new(b"blinded_node_id");
324 hmac.input(control_tlvs_ss.as_ref());
325 Hmac::from_engine(hmac).into_inner()
327 match self.node_signer.ecdh(Recipient::Node, &msg.onion_routing_packet.public_key,
328 Some(&Scalar::from_be_bytes(blinding_factor).unwrap()))
330 Ok(ss) => ss.secret_bytes(),
332 log_trace!(self.logger, "Failed to compute onion packet shared secret");
337 match onion_utils::decode_next_untagged_hop(onion_decode_ss, &msg.onion_routing_packet.hop_data[..],
338 msg.onion_routing_packet.hmac, (control_tlvs_ss, &*self.custom_handler))
340 Ok((Payload::Receive::<<<CMH as Deref>::Target as CustomOnionMessageHandler>::CustomMessage> {
341 message, control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id }), reply_path,
343 log_info!(self.logger,
344 "Received an onion message with path_id {:02x?} and {} reply_path",
345 path_id, if reply_path.is_some() { "a" } else { "no" });
347 OnionMessageContents::Custom(msg) => self.custom_handler.handle_custom_message(msg),
350 Ok((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
351 next_node_id, next_blinding_override
352 })), Some((next_hop_hmac, new_packet_bytes)))) => {
353 // TODO: we need to check whether `next_node_id` is our node, in which case this is a dummy
354 // blinded hop and this onion message is destined for us. In this situation, we should keep
355 // unwrapping the onion layers to get to the final payload. Since we don't have the option
356 // of creating blinded paths with dummy hops currently, we should be ok to not handle this
358 let new_pubkey = match onion_utils::next_hop_packet_pubkey(&self.secp_ctx, msg.onion_routing_packet.public_key, &onion_decode_ss) {
361 log_trace!(self.logger, "Failed to compute next hop packet pubkey: {}", e);
365 let outgoing_packet = Packet {
367 public_key: new_pubkey,
368 hop_data: new_packet_bytes,
371 let onion_message = msgs::OnionMessage {
372 blinding_point: match next_blinding_override {
373 Some(blinding_point) => blinding_point,
375 let blinding_factor = {
376 let mut sha = Sha256::engine();
377 sha.input(&msg.blinding_point.serialize()[..]);
378 sha.input(control_tlvs_ss.as_ref());
379 Sha256::from_engine(sha).into_inner()
381 let next_blinding_point = msg.blinding_point;
382 match next_blinding_point.mul_tweak(&self.secp_ctx, &Scalar::from_be_bytes(blinding_factor).unwrap()) {
385 log_trace!(self.logger, "Failed to compute next blinding point: {}", e);
391 onion_routing_packet: outgoing_packet,
394 let mut pending_per_peer_msgs = self.pending_messages.lock().unwrap();
395 if outbound_buffer_full(&next_node_id, &pending_per_peer_msgs) {
396 log_trace!(self.logger, "Dropping forwarded onion message to peer {:?}: outbound buffer full", next_node_id);
401 pending_per_peer_msgs.entry(next_node_id).or_insert_with(VecDeque::new);
403 match pending_per_peer_msgs.entry(next_node_id) {
404 hash_map::Entry::Vacant(_) => {
405 log_trace!(self.logger, "Dropping forwarded onion message to disconnected peer {:?}", next_node_id);
408 hash_map::Entry::Occupied(mut e) => {
409 e.get_mut().push_back(onion_message);
410 log_trace!(self.logger, "Forwarding an onion message to peer {}", next_node_id);
415 log_trace!(self.logger, "Errored decoding onion message packet: {:?}", e);
418 log_trace!(self.logger, "Received bogus onion message packet, either the sender encoded a final hop as a forwarding hop or vice versa");
423 fn peer_connected(&self, their_node_id: &PublicKey, init: &msgs::Init, _inbound: bool) -> Result<(), ()> {
424 if init.features.supports_onion_messages() {
425 let mut peers = self.pending_messages.lock().unwrap();
426 peers.insert(their_node_id.clone(), VecDeque::new());
431 fn peer_disconnected(&self, their_node_id: &PublicKey) {
432 let mut pending_msgs = self.pending_messages.lock().unwrap();
433 pending_msgs.remove(their_node_id);
436 fn provided_node_features(&self) -> NodeFeatures {
437 let mut features = NodeFeatures::empty();
438 features.set_onion_messages_optional();
442 fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
443 let mut features = InitFeatures::empty();
444 features.set_onion_messages_optional();
449 impl<ES: Deref, NS: Deref, L: Deref, CMH: Deref> OnionMessageProvider for OnionMessenger<ES, NS, L, CMH>
450 where ES::Target: EntropySource,
451 NS::Target: NodeSigner,
453 CMH::Target: CustomOnionMessageHandler,
455 fn next_onion_message_for_peer(&self, peer_node_id: PublicKey) -> Option<msgs::OnionMessage> {
456 let mut pending_msgs = self.pending_messages.lock().unwrap();
457 if let Some(msgs) = pending_msgs.get_mut(&peer_node_id) {
458 return msgs.pop_front()
464 // TODO: parameterize the below Simple* types with OnionMessenger and handle the messages it
466 /// Useful for simplifying the parameters of [`SimpleArcChannelManager`] and
467 /// [`SimpleArcPeerManager`]. See their docs for more details.
469 /// (C-not exported) as `Arc`s don't make sense in bindings.
471 /// [`SimpleArcChannelManager`]: crate::ln::channelmanager::SimpleArcChannelManager
472 /// [`SimpleArcPeerManager`]: crate::ln::peer_handler::SimpleArcPeerManager
473 pub type SimpleArcOnionMessenger<L> = OnionMessenger<Arc<KeysManager>, Arc<KeysManager>, Arc<L>, IgnoringMessageHandler>;
474 /// Useful for simplifying the parameters of [`SimpleRefChannelManager`] and
475 /// [`SimpleRefPeerManager`]. See their docs for more details.
477 /// (C-not exported) as general type aliases don't make sense in bindings.
479 /// [`SimpleRefChannelManager`]: crate::ln::channelmanager::SimpleRefChannelManager
480 /// [`SimpleRefPeerManager`]: crate::ln::peer_handler::SimpleRefPeerManager
481 pub type SimpleRefOnionMessenger<'a, 'b, L> = OnionMessenger<&'a KeysManager, &'a KeysManager, &'b L, IgnoringMessageHandler>;
483 /// Construct onion packet payloads and keys for sending an onion message along the given
484 /// `unblinded_path` to the given `destination`.
485 fn packet_payloads_and_keys<T: CustomOnionMessageContents, S: secp256k1::Signing + secp256k1::Verification>(
486 secp_ctx: &Secp256k1<S>, unblinded_path: &[PublicKey], destination: Destination,
487 message: OnionMessageContents<T>, mut reply_path: Option<BlindedPath>, session_priv: &SecretKey
488 ) -> Result<(Vec<(Payload<T>, [u8; 32])>, Vec<onion_utils::OnionKeys>), secp256k1::Error> {
489 let num_hops = unblinded_path.len() + destination.num_hops();
490 let mut payloads = Vec::with_capacity(num_hops);
491 let mut onion_packet_keys = Vec::with_capacity(num_hops);
493 let (mut intro_node_id_blinding_pt, num_blinded_hops) = if let Destination::BlindedPath(BlindedPath {
494 introduction_node_id, blinding_point, blinded_hops }) = &destination {
495 (Some((*introduction_node_id, *blinding_point)), blinded_hops.len()) } else { (None, 0) };
496 let num_unblinded_hops = num_hops - num_blinded_hops;
498 let mut unblinded_path_idx = 0;
499 let mut blinded_path_idx = 0;
500 let mut prev_control_tlvs_ss = None;
501 let mut final_control_tlvs = None;
502 utils::construct_keys_callback(secp_ctx, unblinded_path, Some(destination), session_priv, |_, onion_packet_ss, ephemeral_pubkey, control_tlvs_ss, unblinded_pk_opt, enc_payload_opt| {
503 if num_unblinded_hops != 0 && unblinded_path_idx < num_unblinded_hops {
504 if let Some(ss) = prev_control_tlvs_ss.take() {
505 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(
507 next_node_id: unblinded_pk_opt.unwrap(),
508 next_blinding_override: None,
512 prev_control_tlvs_ss = Some(control_tlvs_ss);
513 unblinded_path_idx += 1;
514 } else if let Some((intro_node_id, blinding_pt)) = intro_node_id_blinding_pt.take() {
515 if let Some(control_tlvs_ss) = prev_control_tlvs_ss.take() {
516 payloads.push((Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
517 next_node_id: intro_node_id,
518 next_blinding_override: Some(blinding_pt),
519 })), control_tlvs_ss));
522 if blinded_path_idx < num_blinded_hops.saturating_sub(1) && enc_payload_opt.is_some() {
523 payloads.push((Payload::Forward(ForwardControlTlvs::Blinded(enc_payload_opt.unwrap())),
525 blinded_path_idx += 1;
526 } else if let Some(encrypted_payload) = enc_payload_opt {
527 final_control_tlvs = Some(ReceiveControlTlvs::Blinded(encrypted_payload));
528 prev_control_tlvs_ss = Some(control_tlvs_ss);
531 let (rho, mu) = onion_utils::gen_rho_mu_from_shared_secret(onion_packet_ss.as_ref());
532 onion_packet_keys.push(onion_utils::OnionKeys {
534 shared_secret: onion_packet_ss,
536 blinding_factor: [0; 32],
543 if let Some(control_tlvs) = final_control_tlvs {
544 payloads.push((Payload::Receive {
546 reply_path: reply_path.take(),
548 }, prev_control_tlvs_ss.unwrap()));
550 payloads.push((Payload::Receive {
551 control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { path_id: None, }),
552 reply_path: reply_path.take(),
554 }, prev_control_tlvs_ss.unwrap()));
557 Ok((payloads, onion_packet_keys))
560 /// Errors if the serialized payload size exceeds onion_message::BIG_PACKET_HOP_DATA_LEN
561 fn construct_onion_message_packet<T: CustomOnionMessageContents>(payloads: Vec<(Payload<T>, [u8; 32])>, onion_keys: Vec<onion_utils::OnionKeys>, prng_seed: [u8; 32]) -> Result<Packet, ()> {
563 // "`len` allows larger messages to be sent than the standard 1300 bytes allowed for an HTLC
564 // onion, but this should be used sparingly as it is reduces anonymity set, hence the
565 // recommendation that it either look like an HTLC onion, or if larger, be a fixed size."
566 let payloads_ser_len = onion_utils::payloads_serialized_length(&payloads);
567 let hop_data_len = if payloads_ser_len <= SMALL_PACKET_HOP_DATA_LEN {
568 SMALL_PACKET_HOP_DATA_LEN
569 } else if payloads_ser_len <= BIG_PACKET_HOP_DATA_LEN {
570 BIG_PACKET_HOP_DATA_LEN
571 } else { return Err(()) };
573 Ok(onion_utils::construct_onion_message_packet::<_, _>(
574 payloads, onion_keys, prng_seed, hop_data_len))