_ Git - rust-lightning/blob - lightning/src/ln/onion_utils.rs

   1 // This file is Copyright its original authors, visible in version control
   2 // history.
   3 //
   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
   8 // licenses.
   9
  10 use crate::blinded_path::BlindedHop;
  11 use crate::crypto::chacha20::ChaCha20;
  12 use crate::crypto::streams::ChaChaReader;
  13 use crate::ln::channelmanager::{HTLCSource, RecipientOnionFields};
  14 use crate::ln::msgs;
  15 use crate::ln::types::{PaymentHash, PaymentPreimage};
  16 use crate::ln::wire::Encode;
  17 use crate::routing::gossip::NetworkUpdate;
  18 use crate::routing::router::{Path, RouteHop};
  19 use crate::sign::NodeSigner;
  20 use crate::util::errors::{self, APIError};
  21 use crate::util::logger::Logger;
  22 use crate::util::ser::{LengthCalculatingWriter, Readable, ReadableArgs, Writeable, Writer};
  23
  24 use bitcoin::hashes::cmp::fixed_time_eq;
  25 use bitcoin::hashes::hmac::{Hmac, HmacEngine};
  26 use bitcoin::hashes::sha256::Hash as Sha256;
  27 use bitcoin::hashes::{Hash, HashEngine};
  28
  29 use bitcoin::secp256k1;
  30 use bitcoin::secp256k1::ecdh::SharedSecret;
  31 use bitcoin::secp256k1::{PublicKey, Scalar, Secp256k1, SecretKey};
  32
  33 use crate::io::{Cursor, Read};
  34 use core::ops::Deref;
  35
  36 #[allow(unused_imports)]
  37 use crate::prelude::*;
  38
  39 pub(crate) struct OnionKeys {
  40         #[cfg(test)]
  41         pub(crate) shared_secret: SharedSecret,
  42         #[cfg(test)]
  43         pub(crate) blinding_factor: [u8; 32],
  44         pub(crate) ephemeral_pubkey: PublicKey,
  45         pub(crate) rho: [u8; 32],
  46         pub(crate) mu: [u8; 32],
  47 }
  48
  49 #[inline]
  50 pub(crate) fn gen_rho_from_shared_secret(shared_secret: &[u8]) -> [u8; 32] {
  51         assert_eq!(shared_secret.len(), 32);
  52         let mut hmac = HmacEngine::<Sha256>::new(&[0x72, 0x68, 0x6f]); // rho
  53         hmac.input(&shared_secret);
  54         Hmac::from_engine(hmac).to_byte_array()
  55 }
  56
  57 #[inline]
  58 pub(crate) fn gen_rho_mu_from_shared_secret(shared_secret: &[u8]) -> ([u8; 32], [u8; 32]) {
  59         assert_eq!(shared_secret.len(), 32);
  60         let mut engine_rho = HmacEngine::<Sha256>::new(b"rho");
  61         engine_rho.input(&shared_secret);
  62         let hmac_rho = Hmac::from_engine(engine_rho).to_byte_array();
  63
  64         let mut engine_mu = HmacEngine::<Sha256>::new(b"mu");
  65         engine_mu.input(&shared_secret);
  66         let hmac_mu = Hmac::from_engine(engine_mu).to_byte_array();
  67
  68         (hmac_rho, hmac_mu)
  69 }
  70
  71 #[inline]
  72 pub(super) fn gen_um_from_shared_secret(shared_secret: &[u8]) -> [u8; 32] {
  73         assert_eq!(shared_secret.len(), 32);
  74         let mut hmac = HmacEngine::<Sha256>::new(&[0x75, 0x6d]); // um
  75         hmac.input(&shared_secret);
  76         Hmac::from_engine(hmac).to_byte_array()
  77 }
  78
  79 #[inline]
  80 pub(super) fn gen_ammag_from_shared_secret(shared_secret: &[u8]) -> [u8; 32] {
  81         assert_eq!(shared_secret.len(), 32);
  82         let mut hmac = HmacEngine::<Sha256>::new(&[0x61, 0x6d, 0x6d, 0x61, 0x67]); // ammag
  83         hmac.input(&shared_secret);
  84         Hmac::from_engine(hmac).to_byte_array()
  85 }
  86
  87 #[cfg(test)]
  88 #[inline]
  89 pub(super) fn gen_pad_from_shared_secret(shared_secret: &[u8]) -> [u8; 32] {
  90         assert_eq!(shared_secret.len(), 32);
  91         let mut hmac = HmacEngine::<Sha256>::new(&[0x70, 0x61, 0x64]); // pad
  92         hmac.input(&shared_secret);
  93         Hmac::from_engine(hmac).to_byte_array()
  94 }
  95
  96 /// Calculates a pubkey for the next hop, such as the next hop's packet pubkey or blinding point.
  97 pub(crate) fn next_hop_pubkey<T: secp256k1::Verification>(
  98         secp_ctx: &Secp256k1<T>, curr_pubkey: PublicKey, shared_secret: &[u8],
  99 ) -> Result<PublicKey, secp256k1::Error> {
 100         let blinding_factor = {
 101                 let mut sha = Sha256::engine();
 102                 sha.input(&curr_pubkey.serialize()[..]);
 103                 sha.input(shared_secret);
 104                 Sha256::from_engine(sha).to_byte_array()
 105         };
 106
 107         curr_pubkey.mul_tweak(secp_ctx, &Scalar::from_be_bytes(blinding_factor).unwrap())
 108 }
 109
 110 // can only fail if an intermediary hop has an invalid public key or session_priv is invalid
 111 #[inline]
 112 pub(super) fn construct_onion_keys_callback<T, FType>(
 113         secp_ctx: &Secp256k1<T>, path: &Path, session_priv: &SecretKey, mut callback: FType,
 114 ) -> Result<(), secp256k1::Error>
 115 where
 116         T: secp256k1::Signing,
 117         FType: FnMut(SharedSecret, [u8; 32], PublicKey, Option<&RouteHop>, usize),
 118 {
 119         let mut blinded_priv = session_priv.clone();
 120         let mut blinded_pub = PublicKey::from_secret_key(secp_ctx, &blinded_priv);
 121
 122         let unblinded_hops_iter = path.hops.iter().map(|h| (&h.pubkey, Some(h)));
 123         let blinded_pks_iter = path
 124                 .blinded_tail
 125                 .as_ref()
 126                 .map(|t| t.hops.iter())
 127                 .unwrap_or([].iter())
 128                 .skip(1) // Skip the intro node because it's included in the unblinded hops
 129                 .map(|h| (&h.blinded_node_id, None));
 130         for (idx, (pubkey, route_hop_opt)) in unblinded_hops_iter.chain(blinded_pks_iter).enumerate() {
 131                 let shared_secret = SharedSecret::new(pubkey, &blinded_priv);
 132
 133                 let mut sha = Sha256::engine();
 134                 sha.input(&blinded_pub.serialize()[..]);
 135                 sha.input(shared_secret.as_ref());
 136                 let blinding_factor = Sha256::from_engine(sha).to_byte_array();
 137
 138                 let ephemeral_pubkey = blinded_pub;
 139
 140                 blinded_priv = blinded_priv.mul_tweak(&Scalar::from_be_bytes(blinding_factor).unwrap())?;
 141                 blinded_pub = PublicKey::from_secret_key(secp_ctx, &blinded_priv);
 142
 143                 callback(shared_secret, blinding_factor, ephemeral_pubkey, route_hop_opt, idx);
 144         }
 145
 146         Ok(())
 147 }
 148
 149 // can only fail if an intermediary hop has an invalid public key or session_priv is invalid
 150 pub(super) fn construct_onion_keys<T: secp256k1::Signing>(
 151         secp_ctx: &Secp256k1<T>, path: &Path, session_priv: &SecretKey,
 152 ) -> Result<Vec<OnionKeys>, secp256k1::Error> {
 153         let mut res = Vec::with_capacity(path.hops.len());
 154
 155         construct_onion_keys_callback(
 156                 secp_ctx,
 157                 &path,
 158                 session_priv,
 159                 |shared_secret, _blinding_factor, ephemeral_pubkey, _, _| {
 160                         let (rho, mu) = gen_rho_mu_from_shared_secret(shared_secret.as_ref());
 161
 162                         res.push(OnionKeys {
 163                                 #[cfg(test)]
 164                                 shared_secret,
 165                                 #[cfg(test)]
 166                                 blinding_factor: _blinding_factor,
 167                                 ephemeral_pubkey,
 168                                 rho,
 169                                 mu,
 170                         });
 171                 },
 172         )?;
 173
 174         Ok(res)
 175 }
 176
 177 /// returns the hop data, as well as the first-hop value_msat and CLTV value we should send.
 178 pub(super) fn build_onion_payloads<'a>(
 179         path: &'a Path, total_msat: u64, recipient_onion: &'a RecipientOnionFields,
 180         starting_htlc_offset: u32, keysend_preimage: &Option<PaymentPreimage>,
 181 ) -> Result<(Vec<msgs::OutboundOnionPayload<'a>>, u64, u32), APIError> {
 182         let mut res: Vec<msgs::OutboundOnionPayload> = Vec::with_capacity(
 183                 path.hops.len() + path.blinded_tail.as_ref().map_or(0, |t| t.hops.len()),
 184         );
 185         let blinded_tail_with_hop_iter = path.blinded_tail.as_ref().map(|bt| BlindedTailHopIter {
 186                 hops: bt.hops.iter(),
 187                 blinding_point: bt.blinding_point,
 188                 final_value_msat: bt.final_value_msat,
 189                 excess_final_cltv_expiry_delta: bt.excess_final_cltv_expiry_delta,
 190         });
 191
 192         let (value_msat, cltv) = build_onion_payloads_callback(
 193                 path.hops.iter(),
 194                 blinded_tail_with_hop_iter,
 195                 total_msat,
 196                 recipient_onion,
 197                 starting_htlc_offset,
 198                 keysend_preimage,
 199                 |action, payload| match action {
 200                         PayloadCallbackAction::PushBack => res.push(payload),
 201                         PayloadCallbackAction::PushFront => res.insert(0, payload),
 202                 },
 203         )?;
 204         Ok((res, value_msat, cltv))
 205 }
 206
 207 struct BlindedTailHopIter<'a, I: Iterator<Item = &'a BlindedHop>> {
 208         hops: I,
 209         blinding_point: PublicKey,
 210         final_value_msat: u64,
 211         excess_final_cltv_expiry_delta: u32,
 212 }
 213 enum PayloadCallbackAction {
 214         PushBack,
 215         PushFront,
 216 }
 217 fn build_onion_payloads_callback<'a, H, B, F>(
 218         hops: H, mut blinded_tail: Option<BlindedTailHopIter<'a, B>>, total_msat: u64,
 219         recipient_onion: &'a RecipientOnionFields, starting_htlc_offset: u32,
 220         keysend_preimage: &Option<PaymentPreimage>, mut callback: F,
 221 ) -> Result<(u64, u32), APIError>
 222 where
 223         H: DoubleEndedIterator<Item = &'a RouteHop>,
 224         B: ExactSizeIterator<Item = &'a BlindedHop>,
 225         F: FnMut(PayloadCallbackAction, msgs::OutboundOnionPayload<'a>),
 226 {
 227         let mut cur_value_msat = 0u64;
 228         let mut cur_cltv = starting_htlc_offset;
 229         let mut last_short_channel_id = 0;
 230
 231         for (idx, hop) in hops.rev().enumerate() {
 232                 // First hop gets special values so that it can check, on receipt, that everything is
 233                 // exactly as it should be (and the next hop isn't trying to probe to find out if we're
 234                 // the intended recipient).
 235                 let value_msat = if cur_value_msat == 0 { hop.fee_msat } else { cur_value_msat };
 236                 let cltv = if cur_cltv == starting_htlc_offset {
 237                         hop.cltv_expiry_delta + starting_htlc_offset
 238                 } else {
 239                         cur_cltv
 240                 };
 241                 if idx == 0 {
 242                         if let Some(BlindedTailHopIter {
 243                                 blinding_point,
 244                                 hops,
 245                                 final_value_msat,
 246                                 excess_final_cltv_expiry_delta,
 247                                 ..
 248                         }) = blinded_tail.take()
 249                         {
 250                                 let mut blinding_point = Some(blinding_point);
 251                                 let hops_len = hops.len();
 252                                 for (i, blinded_hop) in hops.enumerate() {
 253                                         if i == hops_len - 1 {
 254                                                 cur_value_msat += final_value_msat;
 255                                                 callback(
 256                                                         PayloadCallbackAction::PushBack,
 257                                                         msgs::OutboundOnionPayload::BlindedReceive {
 258                                                                 sender_intended_htlc_amt_msat: final_value_msat,
 259                                                                 total_msat,
 260                                                                 cltv_expiry_height: cur_cltv + excess_final_cltv_expiry_delta,
 261                                                                 encrypted_tlvs: &blinded_hop.encrypted_payload,
 262                                                                 intro_node_blinding_point: blinding_point.take(),
 263                                                                 keysend_preimage: *keysend_preimage,
 264                                                                 custom_tlvs: &recipient_onion.custom_tlvs,
 265                                                         },
 266                                                 );
 267                                         } else {
 268                                                 callback(
 269                                                         PayloadCallbackAction::PushBack,
 270                                                         msgs::OutboundOnionPayload::BlindedForward {
 271                                                                 encrypted_tlvs: &blinded_hop.encrypted_payload,
 272                                                                 intro_node_blinding_point: blinding_point.take(),
 273                                                         },
 274                                                 );
 275                                         }
 276                                 }
 277                         } else {
 278                                 callback(
 279                                         PayloadCallbackAction::PushBack,
 280                                         msgs::OutboundOnionPayload::Receive {
 281                                                 payment_data: recipient_onion.payment_secret.map(|payment_secret| {
 282                                                         msgs::FinalOnionHopData { payment_secret, total_msat }
 283                                                 }),
 284                                                 payment_metadata: recipient_onion.payment_metadata.as_ref(),
 285                                                 keysend_preimage: *keysend_preimage,
 286                                                 custom_tlvs: &recipient_onion.custom_tlvs,
 287                                                 sender_intended_htlc_amt_msat: value_msat,
 288                                                 cltv_expiry_height: cltv,
 289                                         },
 290                                 );
 291                         }
 292                 } else {
 293                         let payload = msgs::OutboundOnionPayload::Forward {
 294                                 short_channel_id: last_short_channel_id,
 295                                 amt_to_forward: value_msat,
 296                                 outgoing_cltv_value: cltv,
 297                         };
 298                         callback(PayloadCallbackAction::PushFront, payload);
 299                 }
 300                 cur_value_msat += hop.fee_msat;
 301                 if cur_value_msat >= 21000000 * 100000000 * 1000 {
 302                         return Err(APIError::InvalidRoute { err: "Channel fees overflowed?".to_owned() });
 303                 }
 304                 cur_cltv += hop.cltv_expiry_delta as u32;
 305                 if cur_cltv >= 500000000 {
 306                         return Err(APIError::InvalidRoute { err: "Channel CLTV overflowed?".to_owned() });
 307                 }
 308                 last_short_channel_id = hop.short_channel_id;
 309         }
 310         Ok((cur_value_msat, cur_cltv))
 311 }
 312
 313 /// Length of the onion data packet. Before TLV-based onions this was 20 65-byte hops, though now
 314 /// the hops can be of variable length.
 315 pub(crate) const ONION_DATA_LEN: usize = 20 * 65;
 316
 317 pub(super) const INVALID_ONION_BLINDING: u16 = 0x8000 | 0x4000 | 24;
 318
 319 #[inline]
 320 fn shift_slice_right(arr: &mut [u8], amt: usize) {
 321         for i in (amt..arr.len()).rev() {
 322                 arr[i] = arr[i - amt];
 323         }
 324         for i in 0..amt {
 325                 arr[i] = 0;
 326         }
 327 }
 328
 329 pub(super) fn construct_onion_packet(
 330         payloads: Vec<msgs::OutboundOnionPayload>, onion_keys: Vec<OnionKeys>, prng_seed: [u8; 32],
 331         associated_data: &PaymentHash,
 332 ) -> Result<msgs::OnionPacket, ()> {
 333         let mut packet_data = [0; ONION_DATA_LEN];
 334
 335         let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
 336         chacha.process(&[0; ONION_DATA_LEN], &mut packet_data);
 337
 338         let packet = FixedSizeOnionPacket(packet_data);
 339         construct_onion_packet_with_init_noise::<_, _>(
 340                 payloads,
 341                 onion_keys,
 342                 packet,
 343                 Some(associated_data),
 344         )
 345 }
 346
 347 #[allow(unused)]
 348 pub(super) fn construct_trampoline_onion_packet(
 349         payloads: Vec<msgs::OutboundTrampolinePayload>, onion_keys: Vec<OnionKeys>,
 350         prng_seed: [u8; 32], associated_data: &PaymentHash, length: u16,
 351 ) -> Result<msgs::TrampolineOnionPacket, ()> {
 352         let mut packet_data = vec![0u8; length as usize];
 353
 354         let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
 355         chacha.process(&vec![0u8; length as usize], &mut packet_data);
 356
 357         construct_onion_packet_with_init_noise::<_, _>(
 358                 payloads,
 359                 onion_keys,
 360                 packet_data,
 361                 Some(associated_data),
 362         )
 363 }
 364
 365 #[cfg(test)]
 366 /// Used in testing to write bogus `BogusOnionHopData` as well as `RawOnionHopData`, which is
 367 /// otherwise not representable in `msgs::OnionHopData`.
 368 pub(super) fn construct_onion_packet_with_writable_hopdata<HD: Writeable>(
 369         payloads: Vec<HD>, onion_keys: Vec<OnionKeys>, prng_seed: [u8; 32],
 370         associated_data: &PaymentHash,
 371 ) -> Result<msgs::OnionPacket, ()> {
 372         let mut packet_data = [0; ONION_DATA_LEN];
 373
 374         let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
 375         chacha.process(&[0; ONION_DATA_LEN], &mut packet_data);
 376
 377         let packet = FixedSizeOnionPacket(packet_data);
 378         construct_onion_packet_with_init_noise::<_, _>(
 379                 payloads,
 380                 onion_keys,
 381                 packet,
 382                 Some(associated_data),
 383         )
 384 }
 385
 386 /// Since onion message packets and onion payment packets have different lengths but are otherwise
 387 /// identical, we use this trait to allow `construct_onion_packet_with_init_noise` to return either
 388 /// type.
 389 pub(crate) trait Packet {
 390         type Data: AsMut<[u8]>;
 391         fn new(pubkey: PublicKey, hop_data: Self::Data, hmac: [u8; 32]) -> Self;
 392 }
 393
 394 // Needed for rustc versions older than 1.47 to avoid E0277: "arrays only have std trait
 395 // implementations for lengths 0..=32".
 396 pub(crate) struct FixedSizeOnionPacket(pub(crate) [u8; ONION_DATA_LEN]);
 397
 398 impl AsMut<[u8]> for FixedSizeOnionPacket {
 399         fn as_mut(&mut self) -> &mut [u8] {
 400                 &mut self.0
 401         }
 402 }
 403
 404 pub(crate) fn payloads_serialized_length<HD: Writeable>(payloads: &Vec<HD>) -> usize {
 405         payloads.iter().map(|p| p.serialized_length() + 32 /* HMAC */).sum()
 406 }
 407
 408 pub(crate) fn construct_onion_message_packet<HD: Writeable, P: Packet<Data = Vec<u8>>>(
 409         payloads: Vec<HD>, onion_keys: Vec<OnionKeys>, prng_seed: [u8; 32], packet_data_len: usize,
 410 ) -> Result<P, ()> {
 411         let mut packet_data = vec![0; packet_data_len];
 412
 413         let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
 414         chacha.process_in_place(&mut packet_data);
 415
 416         construct_onion_packet_with_init_noise::<_, _>(payloads, onion_keys, packet_data, None)
 417 }
 418
 419 fn construct_onion_packet_with_init_noise<HD: Writeable, P: Packet>(
 420         mut payloads: Vec<HD>, onion_keys: Vec<OnionKeys>, mut packet_data: P::Data,
 421         associated_data: Option<&PaymentHash>,
 422 ) -> Result<P, ()> {
 423         let filler = {
 424                 let packet_data = packet_data.as_mut();
 425                 const ONION_HOP_DATA_LEN: usize = 65; // We may decrease this eventually after TLV is common
 426                 let mut res = Vec::with_capacity(ONION_HOP_DATA_LEN * (payloads.len() - 1));
 427
 428                 let mut pos = 0;
 429                 for (i, (payload, keys)) in payloads.iter().zip(onion_keys.iter()).enumerate() {
 430                         let mut chacha = ChaCha20::new(&keys.rho, &[0u8; 8]);
 431                         // TODO: Batch this.
 432                         for _ in 0..(packet_data.len() - pos) {
 433                                 let mut dummy = [0; 1];
 434                                 chacha.process_in_place(&mut dummy); // We don't have a seek function :(
 435                         }
 436
 437                         let mut payload_len = LengthCalculatingWriter(0);
 438                         payload.write(&mut payload_len).expect("Failed to calculate length");
 439                         pos += payload_len.0 + 32;
 440                         if pos > packet_data.len() {
 441                                 return Err(());
 442                         }
 443
 444                         if i == payloads.len() - 1 {
 445                                 break;
 446                         }
 447
 448                         res.resize(pos, 0u8);
 449                         chacha.process_in_place(&mut res);
 450                 }
 451                 res
 452         };
 453
 454         let mut hmac_res = [0; 32];
 455         for (i, (payload, keys)) in payloads.iter_mut().zip(onion_keys.iter()).rev().enumerate() {
 456                 let mut payload_len = LengthCalculatingWriter(0);
 457                 payload.write(&mut payload_len).expect("Failed to calculate length");
 458
 459                 let packet_data = packet_data.as_mut();
 460                 shift_slice_right(packet_data, payload_len.0 + 32);
 461                 packet_data[0..payload_len.0].copy_from_slice(&payload.encode()[..]);
 462                 packet_data[payload_len.0..(payload_len.0 + 32)].copy_from_slice(&hmac_res);
 463
 464                 let mut chacha = ChaCha20::new(&keys.rho, &[0u8; 8]);
 465                 chacha.process_in_place(packet_data);
 466
 467                 if i == 0 {
 468                         let stop_index = packet_data.len();
 469                         let start_index = stop_index.checked_sub(filler.len()).ok_or(())?;
 470                         packet_data[start_index..stop_index].copy_from_slice(&filler[..]);
 471                 }
 472
 473                 let mut hmac = HmacEngine::<Sha256>::new(&keys.mu);
 474                 hmac.input(packet_data);
 475                 if let Some(associated_data) = associated_data {
 476                         hmac.input(&associated_data.0[..]);
 477                 }
 478                 hmac_res = Hmac::from_engine(hmac).to_byte_array();
 479         }
 480
 481         Ok(P::new(onion_keys.first().unwrap().ephemeral_pubkey, packet_data, hmac_res))
 482 }
 483
 484 /// Encrypts a failure packet. raw_packet can either be a
 485 /// msgs::DecodedOnionErrorPacket.encode() result or a msgs::OnionErrorPacket.data element.
 486 pub(super) fn encrypt_failure_packet(
 487         shared_secret: &[u8], raw_packet: &[u8],
 488 ) -> msgs::OnionErrorPacket {
 489         let ammag = gen_ammag_from_shared_secret(&shared_secret);
 490
 491         let mut packet_crypted = Vec::with_capacity(raw_packet.len());
 492         packet_crypted.resize(raw_packet.len(), 0);
 493         let mut chacha = ChaCha20::new(&ammag, &[0u8; 8]);
 494         chacha.process(&raw_packet, &mut packet_crypted[..]);
 495         msgs::OnionErrorPacket { data: packet_crypted }
 496 }
 497
 498 pub(super) fn build_failure_packet(
 499         shared_secret: &[u8], failure_type: u16, failure_data: &[u8],
 500 ) -> msgs::DecodedOnionErrorPacket {
 501         assert_eq!(shared_secret.len(), 32);
 502         assert!(failure_data.len() <= 256 - 2);
 503
 504         let um = gen_um_from_shared_secret(&shared_secret);
 505
 506         let failuremsg = {
 507                 let mut res = Vec::with_capacity(2 + failure_data.len());
 508                 res.push(((failure_type >> 8) & 0xff) as u8);
 509                 res.push(((failure_type >> 0) & 0xff) as u8);
 510                 res.extend_from_slice(&failure_data[..]);
 511                 res
 512         };
 513         let pad = {
 514                 let mut res = Vec::with_capacity(256 - 2 - failure_data.len());
 515                 res.resize(256 - 2 - failure_data.len(), 0);
 516                 res
 517         };
 518         let mut packet = msgs::DecodedOnionErrorPacket { hmac: [0; 32], failuremsg, pad };
 519
 520         let mut hmac = HmacEngine::<Sha256>::new(&um);
 521         hmac.input(&packet.encode()[32..]);
 522         packet.hmac = Hmac::from_engine(hmac).to_byte_array();
 523
 524         packet
 525 }
 526
 527 #[cfg(test)]
 528 pub(super) fn build_first_hop_failure_packet(
 529         shared_secret: &[u8], failure_type: u16, failure_data: &[u8],
 530 ) -> msgs::OnionErrorPacket {
 531         let failure_packet = build_failure_packet(shared_secret, failure_type, failure_data);
 532         encrypt_failure_packet(shared_secret, &failure_packet.encode()[..])
 533 }
 534
 535 pub(crate) struct DecodedOnionFailure {
 536         pub(crate) network_update: Option<NetworkUpdate>,
 537         pub(crate) short_channel_id: Option<u64>,
 538         pub(crate) payment_failed_permanently: bool,
 539         pub(crate) failed_within_blinded_path: bool,
 540         #[cfg(test)]
 541         pub(crate) onion_error_code: Option<u16>,
 542         #[cfg(test)]
 543         pub(crate) onion_error_data: Option<Vec<u8>>,
 544 }
 545
 546 /// Note that we always decrypt `packet` in-place here even if the deserialization into
 547 /// [`msgs::DecodedOnionErrorPacket`] ultimately fails.
 548 fn decrypt_onion_error_packet(
 549         packet: &mut Vec<u8>, shared_secret: SharedSecret,
 550 ) -> Result<msgs::DecodedOnionErrorPacket, msgs::DecodeError> {
 551         let ammag = gen_ammag_from_shared_secret(shared_secret.as_ref());
 552         let mut chacha = ChaCha20::new(&ammag, &[0u8; 8]);
 553         chacha.process_in_place(packet);
 554         msgs::DecodedOnionErrorPacket::read(&mut Cursor::new(packet))
 555 }
 556
 557 /// Process failure we got back from upstream on a payment we sent (implying htlc_source is an
 558 /// OutboundRoute).
 559 #[inline]
 560 pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
 561         secp_ctx: &Secp256k1<T>, logger: &L, htlc_source: &HTLCSource, mut encrypted_packet: Vec<u8>,
 562 ) -> DecodedOnionFailure
 563 where
 564         L::Target: Logger,
 565 {
 566         let (path, session_priv, first_hop_htlc_msat) = match htlc_source {
 567                 HTLCSource::OutboundRoute {
 568                         ref path, ref session_priv, ref first_hop_htlc_msat, ..
 569                 } => (path, session_priv, first_hop_htlc_msat),
 570                 _ => {
 571                         unreachable!()
 572                 },
 573         };
 574
 575         // Learnings from the HTLC failure to inform future payment retries and scoring.
 576         struct FailureLearnings {
 577                 network_update: Option<NetworkUpdate>,
 578                 short_channel_id: Option<u64>,
 579                 payment_failed_permanently: bool,
 580                 failed_within_blinded_path: bool,
 581         }
 582         let mut res: Option<FailureLearnings> = None;
 583         let mut htlc_msat = *first_hop_htlc_msat;
 584         let mut error_code_ret = None;
 585         let mut error_packet_ret = None;
 586         let mut is_from_final_node = false;
 587
 588         const BADONION: u16 = 0x8000;
 589         const PERM: u16 = 0x4000;
 590         const NODE: u16 = 0x2000;
 591         const UPDATE: u16 = 0x1000;
 592
 593         // Handle packed channel/node updates for passing back for the route handler
 594         let callback = |shared_secret, _, _, route_hop_opt: Option<&RouteHop>, route_hop_idx| {
 595                 if res.is_some() {
 596                         return;
 597                 }
 598
 599                 let route_hop = match route_hop_opt {
 600                         Some(hop) => hop,
 601                         None => {
 602                                 // Got an error from within a blinded route.
 603                                 error_code_ret = Some(BADONION | PERM | 24); // invalid_onion_blinding
 604                                 error_packet_ret = Some(vec![0; 32]);
 605                                 res = Some(FailureLearnings {
 606                                         network_update: None,
 607                                         short_channel_id: None,
 608                                         payment_failed_permanently: false,
 609                                         failed_within_blinded_path: true,
 610                                 });
 611                                 return;
 612                         },
 613                 };
 614
 615                 // The failing hop includes either the inbound channel to the recipient or the outbound channel
 616                 // from the current hop (i.e., the next hop's inbound channel).
 617                 let num_blinded_hops = path.blinded_tail.as_ref().map_or(0, |bt| bt.hops.len());
 618                 // For 1-hop blinded paths, the final `path.hops` entry is the recipient.
 619                 is_from_final_node = route_hop_idx + 1 == path.hops.len() && num_blinded_hops <= 1;
 620                 let failing_route_hop = if is_from_final_node {
 621                         route_hop
 622                 } else {
 623                         match path.hops.get(route_hop_idx + 1) {
 624                                 Some(hop) => hop,
 625                                 None => {
 626                                         // The failing hop is within a multi-hop blinded path.
 627                                         #[cfg(not(test))]
 628                                         {
 629                                                 error_code_ret = Some(BADONION | PERM | 24); // invalid_onion_blinding
 630                                                 error_packet_ret = Some(vec![0; 32]);
 631                                         }
 632                                         #[cfg(test)]
 633                                         {
 634                                                 // Actually parse the onion error data in tests so we can check that blinded hops fail
 635                                                 // back correctly.
 636                                                 let err_packet =
 637                                                         decrypt_onion_error_packet(&mut encrypted_packet, shared_secret)
 638                                                                 .unwrap();
 639                                                 error_code_ret = Some(u16::from_be_bytes(
 640                                                         err_packet.failuremsg.get(0..2).unwrap().try_into().unwrap(),
 641                                                 ));
 642                                                 error_packet_ret = Some(err_packet.failuremsg[2..].to_vec());
 643                                         }
 644
 645                                         res = Some(FailureLearnings {
 646                                                 network_update: None,
 647                                                 short_channel_id: None,
 648                                                 payment_failed_permanently: false,
 649                                                 failed_within_blinded_path: true,
 650                                         });
 651                                         return;
 652                                 },
 653                         }
 654                 };
 655
 656                 let amt_to_forward = htlc_msat - route_hop.fee_msat;
 657                 htlc_msat = amt_to_forward;
 658
 659                 let err_packet = match decrypt_onion_error_packet(&mut encrypted_packet, shared_secret) {
 660                         Ok(p) => p,
 661                         Err(_) => return,
 662                 };
 663                 let um = gen_um_from_shared_secret(shared_secret.as_ref());
 664                 let mut hmac = HmacEngine::<Sha256>::new(&um);
 665                 hmac.input(&err_packet.encode()[32..]);
 666
 667                 if !fixed_time_eq(&Hmac::from_engine(hmac).to_byte_array(), &err_packet.hmac) {
 668                         return;
 669                 }
 670                 let error_code_slice = match err_packet.failuremsg.get(0..2) {
 671                         Some(s) => s,
 672                         None => {
 673                                 // Useless packet that we can't use but it passed HMAC, so it definitely came from the peer
 674                                 // in question
 675                                 let network_update = Some(NetworkUpdate::NodeFailure {
 676                                         node_id: route_hop.pubkey,
 677                                         is_permanent: true,
 678                                 });
 679                                 let short_channel_id = Some(route_hop.short_channel_id);
 680                                 res = Some(FailureLearnings {
 681                                         network_update,
 682                                         short_channel_id,
 683                                         payment_failed_permanently: is_from_final_node,
 684                                         failed_within_blinded_path: false,
 685                                 });
 686                                 return;
 687                         },
 688                 };
 689
 690                 let error_code = u16::from_be_bytes(error_code_slice.try_into().expect("len is 2"));
 691                 error_code_ret = Some(error_code);
 692                 error_packet_ret = Some(err_packet.failuremsg[2..].to_vec());
 693
 694                 let (debug_field, debug_field_size) = errors::get_onion_debug_field(error_code);
 695
 696                 // indicate that payment parameter has failed and no need to update Route object
 697                 let payment_failed = match error_code & 0xff {
 698                         15 | 16 | 17 | 18 | 19 | 23 => true,
 699                         _ => false,
 700                 } && is_from_final_node; // PERM bit observed below even if this error is from the intermediate nodes
 701
 702                 let mut network_update = None;
 703                 let mut short_channel_id = None;
 704
 705                 if error_code & BADONION == BADONION {
 706                         // If the error code has the BADONION bit set, always blame the channel from the node
 707                         // "originating" the error to its next hop. The "originator" is ultimately actually claiming
 708                         // that its counterparty is the one who is failing the HTLC.
 709                         // If the "originator" here isn't lying we should really mark the next-hop node as failed
 710                         // entirely, but we can't be confident in that, as it would allow any node to get us to
 711                         // completely ban one of its counterparties. Instead, we simply remove the channel in
 712                         // question.
 713                         network_update = Some(NetworkUpdate::ChannelFailure {
 714                                 short_channel_id: failing_route_hop.short_channel_id,
 715                                 is_permanent: true,
 716                         });
 717                 } else if error_code & NODE == NODE {
 718                         let is_permanent = error_code & PERM == PERM;
 719                         network_update =
 720                                 Some(NetworkUpdate::NodeFailure { node_id: route_hop.pubkey, is_permanent });
 721                         short_channel_id = Some(route_hop.short_channel_id);
 722                 } else if error_code & PERM == PERM {
 723                         if !payment_failed {
 724                                 network_update = Some(NetworkUpdate::ChannelFailure {
 725                                         short_channel_id: failing_route_hop.short_channel_id,
 726                                         is_permanent: true,
 727                                 });
 728                                 short_channel_id = Some(failing_route_hop.short_channel_id);
 729                         }
 730                 } else if error_code & UPDATE == UPDATE {
 731                         if let Some(update_len_slice) =
 732                                 err_packet.failuremsg.get(debug_field_size + 2..debug_field_size + 4)
 733                         {
 734                                 let update_len =
 735                                         u16::from_be_bytes(update_len_slice.try_into().expect("len is 2")) as usize;
 736                                 if let Some(mut update_slice) = err_packet
 737                                         .failuremsg
 738                                         .get(debug_field_size + 4..debug_field_size + 4 + update_len)
 739                                 {
 740                                         // Historically, the BOLTs were unclear if the message type
 741                                         // bytes should be included here or not. The BOLTs have now
 742                                         // been updated to indicate that they *are* included, but many
 743                                         // nodes still send messages without the type bytes, so we
 744                                         // support both here.
 745                                         // TODO: Switch to hard require the type prefix, as the current
 746                                         // permissiveness introduces the (although small) possibility
 747                                         // that we fail to decode legitimate channel updates that
 748                                         // happen to start with ChannelUpdate::TYPE, i.e., [0x01, 0x02].
 749                                         if update_slice.len() > 2
 750                                                 && update_slice[0..2] == msgs::ChannelUpdate::TYPE.to_be_bytes()
 751                                         {
 752                                                 update_slice = &update_slice[2..];
 753                                         } else {
 754                                                 log_trace!(logger, "Failure provided features a channel update without type prefix. Deprecated, but allowing for now.");
 755                                         }
 756                                         let update_opt = msgs::ChannelUpdate::read(&mut Cursor::new(&update_slice));
 757                                         if update_opt.is_ok() || update_slice.is_empty() {
 758                                                 // if channel_update should NOT have caused the failure:
 759                                                 // MAY treat the channel_update as invalid.
 760                                                 let is_chan_update_invalid = match error_code & 0xff {
 761                                                         7 => false,
 762                                                         11 => {
 763                                                                 update_opt.is_ok()
 764                                                                         && amt_to_forward
 765                                                                                 > update_opt.as_ref().unwrap().contents.htlc_minimum_msat
 766                                                         },
 767                                                         12 => {
 768                                                                 update_opt.is_ok()
 769                                                                         && amt_to_forward
 770                                                                                 .checked_mul(
 771                                                                                         update_opt
 772                                                                                                 .as_ref()
 773                                                                                                 .unwrap()
 774                                                                                                 .contents
 775                                                                                                 .fee_proportional_millionths as u64,
 776                                                                                 )
 777                                                                                 .map(|prop_fee| prop_fee / 1_000_000)
 778                                                                                 .and_then(|prop_fee| {
 779                                                                                         prop_fee.checked_add(
 780                                                                                                 update_opt.as_ref().unwrap().contents.fee_base_msat
 781                                                                                                         as u64,
 782                                                                                         )
 783                                                                                 })
 784                                                                                 .map(|fee_msats| route_hop.fee_msat >= fee_msats)
 785                                                                                 .unwrap_or(false)
 786                                                         },
 787                                                         13 => {
 788                                                                 update_opt.is_ok()
 789                                                                         && route_hop.cltv_expiry_delta as u16
 790                                                                                 >= update_opt.as_ref().unwrap().contents.cltv_expiry_delta
 791                                                         },
 792                                                         14 => false, // expiry_too_soon; always valid?
 793                                                         20 => update_opt.as_ref().unwrap().contents.flags & 2 == 0,
 794                                                         _ => false, // unknown error code; take channel_update as valid
 795                                                 };
 796                                                 if is_chan_update_invalid {
 797                                                         // This probably indicates the node which forwarded
 798                                                         // to the node in question corrupted something.
 799                                                         network_update = Some(NetworkUpdate::ChannelFailure {
 800                                                                 short_channel_id: route_hop.short_channel_id,
 801                                                                 is_permanent: true,
 802                                                         });
 803                                                 } else {
 804                                                         if let Ok(chan_update) = update_opt {
 805                                                                 // Make sure the ChannelUpdate contains the expected
 806                                                                 // short channel id.
 807                                                                 if failing_route_hop.short_channel_id
 808                                                                         == chan_update.contents.short_channel_id
 809                                                                 {
 810                                                                         short_channel_id = Some(failing_route_hop.short_channel_id);
 811                                                                 } else {
 812                                                                         log_info!(logger, "Node provided a channel_update for which it was not authoritative, ignoring.");
 813                                                                 }
 814                                                                 network_update =
 815                                                                         Some(NetworkUpdate::ChannelUpdateMessage { msg: chan_update })
 816                                                         } else {
 817                                                                 // The node in question intentionally encoded a 0-length channel update. This is
 818                                                                 // likely due to https://github.com/ElementsProject/lightning/issues/6200.
 819                                                                 short_channel_id = Some(failing_route_hop.short_channel_id);
 820                                                                 network_update = Some(NetworkUpdate::ChannelFailure {
 821                                                                         short_channel_id: failing_route_hop.short_channel_id,
 822                                                                         is_permanent: false,
 823                                                                 });
 824                                                         }
 825                                                 };
 826                                         } else {
 827                                                 // If the channel_update had a non-zero length (i.e. was
 828                                                 // present) but we couldn't read it, treat it as a total
 829                                                 // node failure.
 830                                                 log_info!(
 831                                                         logger,
 832                                                         "Failed to read a channel_update of len {} in an onion",
 833                                                         update_slice.len()
 834                                                 );
 835                                         }
 836                                 }
 837                         }
 838                         if network_update.is_none() {
 839                                 // They provided an UPDATE which was obviously bogus, not worth
 840                                 // trying to relay through them anymore.
 841                                 network_update = Some(NetworkUpdate::NodeFailure {
 842                                         node_id: route_hop.pubkey,
 843                                         is_permanent: true,
 844                                 });
 845                         }
 846                         if short_channel_id.is_none() {
 847                                 short_channel_id = Some(route_hop.short_channel_id);
 848                         }
 849                 } else if payment_failed {
 850                         // Only blame the hop when a value in the HTLC doesn't match the corresponding value in the
 851                         // onion.
 852                         short_channel_id = match error_code & 0xff {
 853                                 18 | 19 => Some(route_hop.short_channel_id),
 854                                 _ => None,
 855                         };
 856                 } else {
 857                         // We can't understand their error messages and they failed to forward...they probably can't
 858                         // understand our forwards so it's really not worth trying any further.
 859                         network_update =
 860                                 Some(NetworkUpdate::NodeFailure { node_id: route_hop.pubkey, is_permanent: true });
 861                         short_channel_id = Some(route_hop.short_channel_id);
 862                 }
 863
 864                 res = Some(FailureLearnings {
 865                         network_update,
 866                         short_channel_id,
 867                         payment_failed_permanently: error_code & PERM == PERM && is_from_final_node,
 868                         failed_within_blinded_path: false,
 869                 });
 870
 871                 let (description, title) = errors::get_onion_error_description(error_code);
 872                 if debug_field_size > 0 && err_packet.failuremsg.len() >= 4 + debug_field_size {
 873                         log_info!(
 874                                 logger,
 875                                 "Onion Error[from {}: {}({:#x}) {}({})] {}",
 876                                 route_hop.pubkey,
 877                                 title,
 878                                 error_code,
 879                                 debug_field,
 880                                 log_bytes!(&err_packet.failuremsg[4..4 + debug_field_size]),
 881                                 description
 882                         );
 883                 } else {
 884                         log_info!(
 885                                 logger,
 886                                 "Onion Error[from {}: {}({:#x})] {}",
 887                                 route_hop.pubkey,
 888                                 title,
 889                                 error_code,
 890                                 description
 891                         );
 892                 }
 893         };
 894
 895         construct_onion_keys_callback(secp_ctx, &path, session_priv, callback)
 896                 .expect("Route that we sent via spontaneously grew invalid keys in the middle of it?");
 897
 898         if let Some(FailureLearnings {
 899                 network_update,
 900                 short_channel_id,
 901                 payment_failed_permanently,
 902                 failed_within_blinded_path,
 903         }) = res
 904         {
 905                 DecodedOnionFailure {
 906                         network_update,
 907                         short_channel_id,
 908                         payment_failed_permanently,
 909                         failed_within_blinded_path,
 910                         #[cfg(test)]
 911                         onion_error_code: error_code_ret,
 912                         #[cfg(test)]
 913                         onion_error_data: error_packet_ret,
 914                 }
 915         } else {
 916                 // only not set either packet unparseable or hmac does not match with any
 917                 // payment not retryable only when garbage is from the final node
 918                 DecodedOnionFailure {
 919                         network_update: None,
 920                         short_channel_id: None,
 921                         payment_failed_permanently: is_from_final_node,
 922                         failed_within_blinded_path: false,
 923                         #[cfg(test)]
 924                         onion_error_code: None,
 925                         #[cfg(test)]
 926                         onion_error_data: None,
 927                 }
 928         }
 929 }
 930
 931 #[derive(Clone)] // See Channel::revoke_and_ack for why, tl;dr: Rust bug
 932 #[cfg_attr(test, derive(PartialEq))]
 933 pub(super) struct HTLCFailReason(HTLCFailReasonRepr);
 934
 935 #[derive(Clone)] // See Channel::revoke_and_ack for why, tl;dr: Rust bug
 936 #[cfg_attr(test, derive(PartialEq))]
 937 enum HTLCFailReasonRepr {
 938         LightningError { err: msgs::OnionErrorPacket },
 939         Reason { failure_code: u16, data: Vec<u8> },
 940 }
 941
 942 impl core::fmt::Debug for HTLCFailReason {
 943         fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
 944                 match self.0 {
 945                         HTLCFailReasonRepr::Reason { ref failure_code, .. } => {
 946                                 write!(f, "HTLC error code {}", failure_code)
 947                         },
 948                         HTLCFailReasonRepr::LightningError { .. } => {
 949                                 write!(f, "pre-built LightningError")
 950                         },
 951                 }
 952         }
 953 }
 954
 955 impl Writeable for HTLCFailReason {
 956         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), crate::io::Error> {
 957                 self.0.write(writer)
 958         }
 959 }
 960 impl Readable for HTLCFailReason {
 961         fn read<R: Read>(reader: &mut R) -> Result<Self, msgs::DecodeError> {
 962                 Ok(Self(Readable::read(reader)?))
 963         }
 964 }
 965
 966 impl_writeable_tlv_based_enum!(HTLCFailReasonRepr,
 967         (0, LightningError) => {
 968                 (0, err, required),
 969         },
 970         (1, Reason) => {
 971                 (0, failure_code, required),
 972                 (2, data, required_vec),
 973         },
 974 ;);
 975
 976 impl HTLCFailReason {
 977         #[rustfmt::skip]
 978         pub(super) fn reason(failure_code: u16, data: Vec<u8>) -> Self {
 979                 const BADONION: u16 = 0x8000;
 980                 const PERM: u16 = 0x4000;
 981                 const NODE: u16 = 0x2000;
 982                 const UPDATE: u16 = 0x1000;
 983
 984                      if failure_code == 1  | PERM { debug_assert!(data.is_empty()) }
 985                 else if failure_code == 2  | NODE { debug_assert!(data.is_empty()) }
 986                 else if failure_code == 2  | PERM | NODE { debug_assert!(data.is_empty()) }
 987                 else if failure_code == 3  | PERM | NODE { debug_assert!(data.is_empty()) }
 988                 else if failure_code == 4  | BADONION | PERM { debug_assert_eq!(data.len(), 32) }
 989                 else if failure_code == 5  | BADONION | PERM { debug_assert_eq!(data.len(), 32) }
 990                 else if failure_code == 6  | BADONION | PERM { debug_assert_eq!(data.len(), 32) }
 991                 else if failure_code == 7  | UPDATE {
 992                         debug_assert_eq!(data.len() - 2, u16::from_be_bytes(data[0..2].try_into().unwrap()) as usize) }
 993                 else if failure_code == 8  | PERM { debug_assert!(data.is_empty()) }
 994                 else if failure_code == 9  | PERM { debug_assert!(data.is_empty()) }
 995                 else if failure_code == 10 | PERM { debug_assert!(data.is_empty()) }
 996                 else if failure_code == 11 | UPDATE {
 997                         debug_assert_eq!(data.len() - 2 - 8, u16::from_be_bytes(data[8..10].try_into().unwrap()) as usize) }
 998                 else if failure_code == 12 | UPDATE {
 999                         debug_assert_eq!(data.len() - 2 - 8, u16::from_be_bytes(data[8..10].try_into().unwrap()) as usize) }
1000                 else if failure_code == 13 | UPDATE {
1001                         debug_assert_eq!(data.len() - 2 - 4, u16::from_be_bytes(data[4..6].try_into().unwrap()) as usize) }
1002                 else if failure_code == 14 | UPDATE {
1003                         debug_assert_eq!(data.len() - 2, u16::from_be_bytes(data[0..2].try_into().unwrap()) as usize) }
1004                 else if failure_code == 15 | PERM { debug_assert_eq!(data.len(), 12) }
1005                 else if failure_code == 18 { debug_assert_eq!(data.len(), 4) }
1006                 else if failure_code == 19 { debug_assert_eq!(data.len(), 8) }
1007                 else if failure_code == 20 | UPDATE {
1008                         debug_assert_eq!(data.len() - 2 - 2, u16::from_be_bytes(data[2..4].try_into().unwrap()) as usize) }
1009                 else if failure_code == 21 { debug_assert!(data.is_empty()) }
1010                 else if failure_code == 22 | PERM { debug_assert!(data.len() <= 11) }
1011                 else if failure_code == 23 { debug_assert!(data.is_empty()) }
1012                 else if failure_code & BADONION != 0 {
1013                         // We set some bogus BADONION failure codes in test, so ignore unknown ones.
1014                 }
1015                 else { debug_assert!(false, "Unknown failure code: {}", failure_code) }
1016
1017                 Self(HTLCFailReasonRepr::Reason { failure_code, data })
1018         }
1019
1020         pub(super) fn from_failure_code(failure_code: u16) -> Self {
1021                 Self::reason(failure_code, Vec::new())
1022         }
1023
1024         pub(super) fn from_msg(msg: &msgs::UpdateFailHTLC) -> Self {
1025                 Self(HTLCFailReasonRepr::LightningError { err: msg.reason.clone() })
1026         }
1027
1028         pub(super) fn get_encrypted_failure_packet(
1029                 &self, incoming_packet_shared_secret: &[u8; 32], phantom_shared_secret: &Option<[u8; 32]>,
1030         ) -> msgs::OnionErrorPacket {
1031                 match self.0 {
1032                         HTLCFailReasonRepr::Reason { ref failure_code, ref data } => {
1033                                 if let Some(phantom_ss) = phantom_shared_secret {
1034                                         let phantom_packet =
1035                                                 build_failure_packet(phantom_ss, *failure_code, &data[..]).encode();
1036                                         let encrypted_phantom_packet =
1037                                                 encrypt_failure_packet(phantom_ss, &phantom_packet);
1038                                         encrypt_failure_packet(
1039                                                 incoming_packet_shared_secret,
1040                                                 &encrypted_phantom_packet.data[..],
1041                                         )
1042                                 } else {
1043                                         let packet = build_failure_packet(
1044                                                 incoming_packet_shared_secret,
1045                                                 *failure_code,
1046                                                 &data[..],
1047                                         )
1048                                         .encode();
1049                                         encrypt_failure_packet(incoming_packet_shared_secret, &packet)
1050                                 }
1051                         },
1052                         HTLCFailReasonRepr::LightningError { ref err } => {
1053                                 encrypt_failure_packet(incoming_packet_shared_secret, &err.data)
1054                         },
1055                 }
1056         }
1057
1058         pub(super) fn decode_onion_failure<T: secp256k1::Signing, L: Deref>(
1059                 &self, secp_ctx: &Secp256k1<T>, logger: &L, htlc_source: &HTLCSource,
1060         ) -> DecodedOnionFailure
1061         where
1062                 L::Target: Logger,
1063         {
1064                 match self.0 {
1065                         HTLCFailReasonRepr::LightningError { ref err } => {
1066                                 process_onion_failure(secp_ctx, logger, &htlc_source, err.data.clone())
1067                         },
1068                         #[allow(unused)]
1069                         HTLCFailReasonRepr::Reason { ref failure_code, ref data, .. } => {
1070                                 // we get a fail_malformed_htlc from the first hop
1071                                 // TODO: We'd like to generate a NetworkUpdate for temporary
1072                                 // failures here, but that would be insufficient as find_route
1073                                 // generally ignores its view of our own channels as we provide them via
1074                                 // ChannelDetails.
1075                                 if let &HTLCSource::OutboundRoute { ref path, .. } = htlc_source {
1076                                         DecodedOnionFailure {
1077                                                 network_update: None,
1078                                                 payment_failed_permanently: false,
1079                                                 short_channel_id: Some(path.hops[0].short_channel_id),
1080                                                 failed_within_blinded_path: false,
1081                                                 #[cfg(test)]
1082                                                 onion_error_code: Some(*failure_code),
1083                                                 #[cfg(test)]
1084                                                 onion_error_data: Some(data.clone()),
1085                                         }
1086                                 } else {
1087                                         unreachable!();
1088                                 }
1089                         },
1090                 }
1091         }
1092 }
1093
1094 /// Allows `decode_next_hop` to return the next hop packet bytes for either payments or onion
1095 /// message forwards.
1096 pub(crate) trait NextPacketBytes: AsMut<[u8]> {
1097         fn new(len: usize) -> Self;
1098 }
1099
1100 impl NextPacketBytes for FixedSizeOnionPacket {
1101         fn new(_len: usize) -> Self {
1102                 Self([0 as u8; ONION_DATA_LEN])
1103         }
1104 }
1105
1106 impl NextPacketBytes for Vec<u8> {
1107         fn new(len: usize) -> Self {
1108                 vec![0 as u8; len]
1109         }
1110 }
1111
1112 /// Data decrypted from a payment's onion payload.
1113 pub(crate) enum Hop {
1114         /// This onion payload was for us, not for forwarding to a next-hop. Contains information for
1115         /// verifying the incoming payment.
1116         Receive(msgs::InboundOnionPayload),
1117         /// This onion payload needs to be forwarded to a next-hop.
1118         Forward {
1119                 /// Onion payload data used in forwarding the payment.
1120                 next_hop_data: msgs::InboundOnionPayload,
1121                 /// HMAC of the next hop's onion packet.
1122                 next_hop_hmac: [u8; 32],
1123                 /// Bytes of the onion packet we're forwarding.
1124                 new_packet_bytes: [u8; ONION_DATA_LEN],
1125         },
1126 }
1127
1128 impl Hop {
1129         pub(crate) fn is_intro_node_blinded_forward(&self) -> bool {
1130                 match self {
1131                         Self::Forward {
1132                                 next_hop_data:
1133                                         msgs::InboundOnionPayload::BlindedForward {
1134                                                 intro_node_blinding_point: Some(_), ..
1135                                         },
1136                                 ..
1137                         } => true,
1138                         _ => false,
1139                 }
1140         }
1141 }
1142
1143 /// Error returned when we fail to decode the onion packet.
1144 #[derive(Debug)]
1145 pub(crate) enum OnionDecodeErr {
1146         /// The HMAC of the onion packet did not match the hop data.
1147         Malformed { err_msg: &'static str, err_code: u16 },
1148         /// We failed to decode the onion payload.
1149         Relay { err_msg: &'static str, err_code: u16 },
1150 }
1151
1152 pub(crate) fn decode_next_payment_hop<NS: Deref>(
1153         shared_secret: [u8; 32], hop_data: &[u8], hmac_bytes: [u8; 32], payment_hash: PaymentHash,
1154         blinding_point: Option<PublicKey>, node_signer: &NS,
1155 ) -> Result<Hop, OnionDecodeErr>
1156 where
1157         NS::Target: NodeSigner,
1158 {
1159         match decode_next_hop(
1160                 shared_secret,
1161                 hop_data,
1162                 hmac_bytes,
1163                 Some(payment_hash),
1164                 (blinding_point, node_signer),
1165         ) {
1166                 Ok((next_hop_data, None)) => Ok(Hop::Receive(next_hop_data)),
1167                 Ok((next_hop_data, Some((next_hop_hmac, FixedSizeOnionPacket(new_packet_bytes))))) => {
1168                         Ok(Hop::Forward { next_hop_data, next_hop_hmac, new_packet_bytes })
1169                 },
1170                 Err(e) => Err(e),
1171         }
1172 }
1173
1174 /// Build a payment onion, returning the first hop msat and cltv values as well.
1175 /// `cur_block_height` should be set to the best known block height + 1.
1176 pub fn create_payment_onion<T: secp256k1::Signing>(
1177         secp_ctx: &Secp256k1<T>, path: &Path, session_priv: &SecretKey, total_msat: u64,
1178         recipient_onion: &RecipientOnionFields, cur_block_height: u32, payment_hash: &PaymentHash,
1179         keysend_preimage: &Option<PaymentPreimage>, prng_seed: [u8; 32],
1180 ) -> Result<(msgs::OnionPacket, u64, u32), APIError> {
1181         let onion_keys = construct_onion_keys(&secp_ctx, &path, &session_priv).map_err(|_| {
1182                 APIError::InvalidRoute { err: "Pubkey along hop was maliciously selected".to_owned() }
1183         })?;
1184         let (onion_payloads, htlc_msat, htlc_cltv) = build_onion_payloads(
1185                 &path,
1186                 total_msat,
1187                 recipient_onion,
1188                 cur_block_height,
1189                 keysend_preimage,
1190         )?;
1191         let onion_packet = construct_onion_packet(onion_payloads, onion_keys, prng_seed, payment_hash)
1192                 .map_err(|_| APIError::InvalidRoute {
1193                         err: "Route size too large considering onion data".to_owned(),
1194                 })?;
1195         Ok((onion_packet, htlc_msat, htlc_cltv))
1196 }
1197
1198 pub(crate) fn decode_next_untagged_hop<T, R: ReadableArgs<T>, N: NextPacketBytes>(
1199         shared_secret: [u8; 32], hop_data: &[u8], hmac_bytes: [u8; 32], read_args: T,
1200 ) -> Result<(R, Option<([u8; 32], N)>), OnionDecodeErr> {
1201         decode_next_hop(shared_secret, hop_data, hmac_bytes, None, read_args)
1202 }
1203
1204 fn decode_next_hop<T, R: ReadableArgs<T>, N: NextPacketBytes>(
1205         shared_secret: [u8; 32], hop_data: &[u8], hmac_bytes: [u8; 32],
1206         payment_hash: Option<PaymentHash>, read_args: T,
1207 ) -> Result<(R, Option<([u8; 32], N)>), OnionDecodeErr> {
1208         let (rho, mu) = gen_rho_mu_from_shared_secret(&shared_secret);
1209         let mut hmac = HmacEngine::<Sha256>::new(&mu);
1210         hmac.input(hop_data);
1211         if let Some(tag) = payment_hash {
1212                 hmac.input(&tag.0[..]);
1213         }
1214         if !fixed_time_eq(&Hmac::from_engine(hmac).to_byte_array(), &hmac_bytes) {
1215                 return Err(OnionDecodeErr::Malformed {
1216                         err_msg: "HMAC Check failed",
1217                         err_code: 0x8000 | 0x4000 | 5,
1218                 });
1219         }
1220
1221         let mut chacha = ChaCha20::new(&rho, &[0u8; 8]);
1222         let mut chacha_stream = ChaChaReader { chacha: &mut chacha, read: Cursor::new(&hop_data[..]) };
1223         match R::read(&mut chacha_stream, read_args) {
1224                 Err(err) => {
1225                         let error_code = match err {
1226                                 // Unknown realm byte
1227                                 msgs::DecodeError::UnknownVersion => 0x4000 | 1,
1228                                 // invalid_onion_payload
1229                                 msgs::DecodeError::UnknownRequiredFeature
1230                                 | msgs::DecodeError::InvalidValue
1231                                 | msgs::DecodeError::ShortRead => 0x4000 | 22,
1232                                 // Should never happen
1233                                 _ => 0x2000 | 2,
1234                         };
1235                         return Err(OnionDecodeErr::Relay {
1236                                 err_msg: "Unable to decode our hop data",
1237                                 err_code: error_code,
1238                         });
1239                 },
1240                 Ok(msg) => {
1241                         let mut hmac = [0; 32];
1242                         if let Err(_) = chacha_stream.read_exact(&mut hmac[..]) {
1243                                 return Err(OnionDecodeErr::Relay {
1244                                         err_msg: "Unable to decode our hop data",
1245                                         err_code: 0x4000 | 22,
1246                                 });
1247                         }
1248                         if hmac == [0; 32] {
1249                                 #[cfg(test)]
1250                                 {
1251                                         if chacha_stream.read.position() < hop_data.len() as u64 - 64 {
1252                                                 // In tests, make sure that the initial onion packet data is, at least, non-0.
1253                                                 // We could do some fancy randomness test here, but, ehh, whatever.
1254                                                 // This checks for the issue where you can calculate the path length given the
1255                                                 // onion data as all the path entries that the originator sent will be here
1256                                                 // as-is (and were originally 0s).
1257                                                 // Of course reverse path calculation is still pretty easy given naive routing
1258                                                 // algorithms, but this fixes the most-obvious case.
1259                                                 let mut next_bytes = [0; 32];
1260                                                 chacha_stream.read_exact(&mut next_bytes).unwrap();
1261                                                 assert_ne!(next_bytes[..], [0; 32][..]);
1262                                                 chacha_stream.read_exact(&mut next_bytes).unwrap();
1263                                                 assert_ne!(next_bytes[..], [0; 32][..]);
1264                                         }
1265                                 }
1266                                 return Ok((msg, None)); // We are the final destination for this packet
1267                         } else {
1268                                 let mut new_packet_bytes = N::new(hop_data.len());
1269                                 let read_pos = hop_data.len() - chacha_stream.read.position() as usize;
1270                                 chacha_stream.read_exact(&mut new_packet_bytes.as_mut()[..read_pos]).unwrap();
1271                                 #[cfg(debug_assertions)]
1272                                 {
1273                                         // Check two things:
1274                                         // a) that the behavior of our stream here will return Ok(0) even if the TLV
1275                                         //    read above emptied out our buffer and the unwrap() wont needlessly panic
1276                                         // b) that we didn't somehow magically end up with extra data.
1277                                         let mut t = [0; 1];
1278                                         debug_assert!(chacha_stream.read(&mut t).unwrap() == 0);
1279                                 }
1280                                 // Once we've emptied the set of bytes our peer gave us, encrypt 0 bytes until we
1281                                 // fill the onion hop data we'll forward to our next-hop peer.
1282                                 chacha_stream.chacha.process_in_place(&mut new_packet_bytes.as_mut()[read_pos..]);
1283                                 return Ok((msg, Some((hmac, new_packet_bytes)))); // This packet needs forwarding
1284                         }
1285                 },
1286         }
1287 }
1288
1289 #[cfg(test)]
1290 mod tests {
1291         use crate::io;
1292         use crate::ln::features::{ChannelFeatures, NodeFeatures};
1293         use crate::ln::msgs;
1294         use crate::ln::types::PaymentHash;
1295         use crate::routing::router::{Path, Route, RouteHop};
1296         use crate::util::ser::{VecWriter, Writeable, Writer};
1297
1298         #[allow(unused_imports)]
1299         use crate::prelude::*;
1300
1301         use bitcoin::hashes::hex::FromHex;
1302         use bitcoin::secp256k1::Secp256k1;
1303         use bitcoin::secp256k1::{PublicKey, SecretKey};
1304
1305         use super::OnionKeys;
1306
1307         fn get_test_session_key() -> SecretKey {
1308                 let hex = "4141414141414141414141414141414141414141414141414141414141414141";
1309                 SecretKey::from_slice(&<Vec<u8>>::from_hex(hex).unwrap()[..]).unwrap()
1310         }
1311
1312         fn build_test_onion_keys() -> Vec<OnionKeys> {
1313                 // Keys from BOLT 4, used in both test vector tests
1314                 let secp_ctx = Secp256k1::new();
1315
1316                 let route = Route {
1317                         paths: vec![Path { hops: vec![
1318                                         RouteHop {
1319                                                 pubkey: PublicKey::from_slice(&<Vec<u8>>::from_hex("02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619").unwrap()[..]).unwrap(),
1320                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
1321                                                 short_channel_id: 0, fee_msat: 0, cltv_expiry_delta: 0, maybe_announced_channel: true, // We fill in the payloads manually instead of generating them from RouteHops.
1322                                         },
1323                                         RouteHop {
1324                                                 pubkey: PublicKey::from_slice(&<Vec<u8>>::from_hex("0324653eac434488002cc06bbfb7f10fe18991e35f9fe4302dbea6d2353dc0ab1c").unwrap()[..]).unwrap(),
1325                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
1326                                                 short_channel_id: 0, fee_msat: 0, cltv_expiry_delta: 0, maybe_announced_channel: true, // We fill in the payloads manually instead of generating them from RouteHops.
1327                                         },
1328                                         RouteHop {
1329                                                 pubkey: PublicKey::from_slice(&<Vec<u8>>::from_hex("027f31ebc5462c1fdce1b737ecff52d37d75dea43ce11c74d25aa297165faa2007").unwrap()[..]).unwrap(),
1330                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
1331                                                 short_channel_id: 0, fee_msat: 0, cltv_expiry_delta: 0, maybe_announced_channel: true, // We fill in the payloads manually instead of generating them from RouteHops.
1332                                         },
1333                                         RouteHop {
1334                                                 pubkey: PublicKey::from_slice(&<Vec<u8>>::from_hex("032c0b7cf95324a07d05398b240174dc0c2be444d96b159aa6c7f7b1e668680991").unwrap()[..]).unwrap(),
1335                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
1336                                                 short_channel_id: 0, fee_msat: 0, cltv_expiry_delta: 0, maybe_announced_channel: true, // We fill in the payloads manually instead of generating them from RouteHops.
1337                                         },
1338                                         RouteHop {
1339                                                 pubkey: PublicKey::from_slice(&<Vec<u8>>::from_hex("02edabbd16b41c8371b92ef2f04c1185b4f03b6dcd52ba9b78d9d7c89c8f221145").unwrap()[..]).unwrap(),
1340                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
1341                                                 short_channel_id: 0, fee_msat: 0, cltv_expiry_delta: 0, maybe_announced_channel: true, // We fill in the payloads manually instead of generating them from RouteHops.
1342                                         },
1343                         ], blinded_tail: None }],
1344                         route_params: None,
1345                 };
1346
1347                 let onion_keys =
1348                         super::construct_onion_keys(&secp_ctx, &route.paths[0], &get_test_session_key())
1349                                 .unwrap();
1350                 assert_eq!(onion_keys.len(), route.paths[0].hops.len());
1351                 onion_keys
1352         }
1353
1354         #[test]
1355         fn onion_vectors() {
1356                 let onion_keys = build_test_onion_keys();
1357
1358                 // Test generation of ephemeral keys and secrets. These values used to be part of the BOLT4
1359                 // test vectors, but have since been removed. We keep them as they provide test coverage.
1360                 let hex = "53eb63ea8a3fec3b3cd433b85cd62a4b145e1dda09391b348c4e1cd36a03ea66";
1361                 assert_eq!(
1362                         onion_keys[0].shared_secret.secret_bytes(),
1363                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1364                 );
1365
1366                 let hex = "2ec2e5da605776054187180343287683aa6a51b4b1c04d6dd49c45d8cffb3c36";
1367                 assert_eq!(onion_keys[0].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
1368
1369                 let hex = "02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619";
1370                 assert_eq!(
1371                         onion_keys[0].ephemeral_pubkey.serialize()[..],
1372                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1373                 );
1374
1375                 let hex = "ce496ec94def95aadd4bec15cdb41a740c9f2b62347c4917325fcc6fb0453986";
1376                 assert_eq!(onion_keys[0].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1377
1378                 let hex = "b57061dc6d0a2b9f261ac410c8b26d64ac5506cbba30267a649c28c179400eba";
1379                 assert_eq!(onion_keys[0].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1380
1381                 let hex = "a6519e98832a0b179f62123b3567c106db99ee37bef036e783263602f3488fae";
1382                 assert_eq!(
1383                         onion_keys[1].shared_secret.secret_bytes(),
1384                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1385                 );
1386
1387                 let hex = "bf66c28bc22e598cfd574a1931a2bafbca09163df2261e6d0056b2610dab938f";
1388                 assert_eq!(onion_keys[1].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
1389
1390                 let hex = "028f9438bfbf7feac2e108d677e3a82da596be706cc1cf342b75c7b7e22bf4e6e2";
1391                 assert_eq!(
1392                         onion_keys[1].ephemeral_pubkey.serialize()[..],
1393                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1394                 );
1395
1396                 let hex = "450ffcabc6449094918ebe13d4f03e433d20a3d28a768203337bc40b6e4b2c59";
1397                 assert_eq!(onion_keys[1].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1398
1399                 let hex = "05ed2b4a3fb023c2ff5dd6ed4b9b6ea7383f5cfe9d59c11d121ec2c81ca2eea9";
1400                 assert_eq!(onion_keys[1].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1401
1402                 let hex = "3a6b412548762f0dbccce5c7ae7bb8147d1caf9b5471c34120b30bc9c04891cc";
1403                 assert_eq!(
1404                         onion_keys[2].shared_secret.secret_bytes(),
1405                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1406                 );
1407
1408                 let hex = "a1f2dadd184eb1627049673f18c6325814384facdee5bfd935d9cb031a1698a5";
1409                 assert_eq!(onion_keys[2].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
1410
1411                 let hex = "03bfd8225241ea71cd0843db7709f4c222f62ff2d4516fd38b39914ab6b83e0da0";
1412                 assert_eq!(
1413                         onion_keys[2].ephemeral_pubkey.serialize()[..],
1414                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1415                 );
1416
1417                 let hex = "11bf5c4f960239cb37833936aa3d02cea82c0f39fd35f566109c41f9eac8deea";
1418                 assert_eq!(onion_keys[2].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1419
1420                 let hex = "caafe2820fa00eb2eeb78695ae452eba38f5a53ed6d53518c5c6edf76f3f5b78";
1421                 assert_eq!(onion_keys[2].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1422
1423                 let hex = "21e13c2d7cfe7e18836df50872466117a295783ab8aab0e7ecc8c725503ad02d";
1424                 assert_eq!(
1425                         onion_keys[3].shared_secret.secret_bytes(),
1426                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1427                 );
1428
1429                 let hex = "7cfe0b699f35525029ae0fa437c69d0f20f7ed4e3916133f9cacbb13c82ff262";
1430                 assert_eq!(onion_keys[3].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
1431
1432                 let hex = "031dde6926381289671300239ea8e57ffaf9bebd05b9a5b95beaf07af05cd43595";
1433                 assert_eq!(
1434                         onion_keys[3].ephemeral_pubkey.serialize()[..],
1435                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1436                 );
1437
1438                 let hex = "cbe784ab745c13ff5cffc2fbe3e84424aa0fd669b8ead4ee562901a4a4e89e9e";
1439                 assert_eq!(onion_keys[3].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1440
1441                 let hex = "5052aa1b3d9f0655a0932e50d42f0c9ba0705142c25d225515c45f47c0036ee9";
1442                 assert_eq!(onion_keys[3].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1443
1444                 let hex = "b5756b9b542727dbafc6765a49488b023a725d631af688fc031217e90770c328";
1445                 assert_eq!(
1446                         onion_keys[4].shared_secret.secret_bytes(),
1447                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1448                 );
1449
1450                 let hex = "c96e00dddaf57e7edcd4fb5954be5b65b09f17cb6d20651b4e90315be5779205";
1451                 assert_eq!(onion_keys[4].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
1452
1453                 let hex = "03a214ebd875aab6ddfd77f22c5e7311d7f77f17a169e599f157bbcdae8bf071f4";
1454                 assert_eq!(
1455                         onion_keys[4].ephemeral_pubkey.serialize()[..],
1456                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1457                 );
1458
1459                 let hex = "034e18b8cc718e8af6339106e706c52d8df89e2b1f7e9142d996acf88df8799b";
1460                 assert_eq!(onion_keys[4].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1461
1462                 let hex = "8e45e5c61c2b24cb6382444db6698727afb063adecd72aada233d4bf273d975a";
1463                 assert_eq!(onion_keys[4].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1464
1465                 // Packet creation test vectors from BOLT 4 (see
1466                 // https://github.com/lightning/bolts/blob/16973e2b857e853308cafd59e42fa830d75b1642/bolt04/onion-test.json).
1467                 // Note that we represent the test vector payloads 2 and 5 through RawOnionHopData::data
1468                 // with raw hex instead of our in-memory enums, as the payloads contains custom types, and
1469                 // we have no way of representing that with our enums.
1470                 let payloads = vec!(
1471                         RawOnionHopData::new(msgs::OutboundOnionPayload::Forward {
1472                                 short_channel_id: 1,
1473                                 amt_to_forward: 15000,
1474                                 outgoing_cltv_value: 1500,
1475                         }),
1476                         /*
1477                         The second payload is represented by raw hex as it contains custom type data. Content:
1478                         1. length "52" (payload_length 82).
1479
1480                         The first part of the payload has the `NonFinalNode` format, with content as follows:
1481                         2. amt_to_forward "020236b0"
1482                            02 (type amt_to_forward) 02 (length 2) 36b0 (value 14000)
1483                         3. outgoing_cltv_value "04020578"
1484                            04 (type outgoing_cltv_value) 02 (length 2) 0578 (value 1400)
1485                         4. short_channel_id "06080000000000000002"
1486                            06 (type short_channel_id) 08 (length 8) 0000000000000002 (value 2)
1487
1488                         The rest of the payload is custom type data:
1489                         5. custom_record "fd02013c0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f"
1490                         */
1491                         RawOnionHopData {
1492                                 data: <Vec<u8>>::from_hex("52020236b00402057806080000000000000002fd02013c0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f").unwrap(),
1493                         },
1494                         RawOnionHopData::new(msgs::OutboundOnionPayload::Forward {
1495                                 short_channel_id: 3,
1496                                 amt_to_forward: 12500,
1497                                 outgoing_cltv_value: 1250,
1498                         }),
1499                         RawOnionHopData::new(msgs::OutboundOnionPayload::Forward {
1500                                 short_channel_id: 4,
1501                                 amt_to_forward: 10000,
1502                                 outgoing_cltv_value: 1000,
1503                         }),
1504                         /*
1505                         The fifth payload is represented by raw hex as it contains custom type data. Content:
1506                         1. length "fd0110" (payload_length 272).
1507
1508                         The first part of the payload has the `FinalNode` format, with content as follows:
1509                         1. amt_to_forward "02022710"
1510                            02 (type amt_to_forward) 02 (length 2) 2710 (value 10000)
1511                         2. outgoing_cltv_value "040203e8"
1512                            04 (type outgoing_cltv_value) 02 (length 2) 03e8 (value 1000)
1513                         3. payment_data "082224a33562c54507a9334e79f0dc4f17d407e6d7c61f0e2f3d0d38599502f617042710"
1514                            08 (type short_channel_id) 22 (length 34) 24a33562c54507a9334e79f0dc4f17d407e6d7c61f0e2f3d0d38599502f61704 (payment_secret) 2710 (total_msat value 10000)
1515
1516                         The rest of the payload is custom type data:
1517                         4. custom_record "fd012de02a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a"
1518                         */
1519                         RawOnionHopData {
1520                                 data: <Vec<u8>>::from_hex("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").unwrap(),
1521                         },
1522                 );
1523
1524                 // Verify that the serialized OnionHopDataFormat::NonFinalNode tlv payloads matches the test vectors
1525                 let mut w = VecWriter(Vec::new());
1526                 payloads[0].write(&mut w).unwrap();
1527                 let hop_1_serialized_payload = w.0;
1528                 let hex = "1202023a98040205dc06080000000000000001";
1529                 let expected_serialized_hop_1_payload = &<Vec<u8>>::from_hex(hex).unwrap()[..];
1530                 assert_eq!(hop_1_serialized_payload, expected_serialized_hop_1_payload);
1531
1532                 w = VecWriter(Vec::new());
1533                 payloads[2].write(&mut w).unwrap();
1534                 let hop_3_serialized_payload = w.0;
1535                 let hex = "12020230d4040204e206080000000000000003";
1536                 let expected_serialized_hop_3_payload = &<Vec<u8>>::from_hex(hex).unwrap()[..];
1537                 assert_eq!(hop_3_serialized_payload, expected_serialized_hop_3_payload);
1538
1539                 w = VecWriter(Vec::new());
1540                 payloads[3].write(&mut w).unwrap();
1541                 let hop_4_serialized_payload = w.0;
1542                 let hex = "1202022710040203e806080000000000000004";
1543                 let expected_serialized_hop_4_payload = &<Vec<u8>>::from_hex(hex).unwrap()[..];
1544                 assert_eq!(hop_4_serialized_payload, expected_serialized_hop_4_payload);
1545
1546                 let pad_keytype_seed =
1547                         super::gen_pad_from_shared_secret(&get_test_session_key().secret_bytes());
1548
1549                 let packet: msgs::OnionPacket = super::construct_onion_packet_with_writable_hopdata::<_>(
1550                         payloads,
1551                         onion_keys,
1552                         pad_keytype_seed,
1553                         &PaymentHash([0x42; 32]),
1554                 )
1555                 .unwrap();
1556
1557                 let hex = 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
1558                 assert_eq!(packet.encode(), <Vec<u8>>::from_hex(hex).unwrap());
1559         }
1560
1561         #[test]
1562         fn test_failure_packet_onion() {
1563                 // Returning Errors test vectors from BOLT 4
1564
1565                 let onion_keys = build_test_onion_keys();
1566                 let onion_error =
1567                         super::build_failure_packet(onion_keys[4].shared_secret.as_ref(), 0x2002, &[0; 0]);
1568                 let hex = "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";
1569                 assert_eq!(onion_error.encode(), <Vec<u8>>::from_hex(hex).unwrap());
1570
1571                 let onion_packet_1 = super::encrypt_failure_packet(
1572                         onion_keys[4].shared_secret.as_ref(),
1573                         &onion_error.encode()[..],
1574                 );
1575                 let hex = "a5e6bd0c74cb347f10cce367f949098f2457d14c046fd8a22cb96efb30b0fdcda8cb9168b50f2fd45edd73c1b0c8b33002df376801ff58aaa94000bf8a86f92620f343baef38a580102395ae3abf9128d1047a0736ff9b83d456740ebbb4aeb3aa9737f18fb4afb4aa074fb26c4d702f42968888550a3bded8c05247e045b866baef0499f079fdaeef6538f31d44deafffdfd3afa2fb4ca9082b8f1c465371a9894dd8c243fb4847e004f5256b3e90e2edde4c9fb3082ddfe4d1e734cacd96ef0706bf63c9984e22dc98851bcccd1c3494351feb458c9c6af41c0044bea3c47552b1d992ae542b17a2d0bba1a096c78d169034ecb55b6e3a7263c26017f033031228833c1daefc0dedb8cf7c3e37c9c37ebfe42f3225c326e8bcfd338804c145b16e34e4";
1576                 assert_eq!(onion_packet_1.data, <Vec<u8>>::from_hex(hex).unwrap());
1577
1578                 let onion_packet_2 = super::encrypt_failure_packet(
1579                         onion_keys[3].shared_secret.as_ref(),
1580                         &onion_packet_1.data[..],
1581                 );
1582                 let hex = "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";
1583                 assert_eq!(onion_packet_2.data, <Vec<u8>>::from_hex(hex).unwrap());
1584
1585                 let onion_packet_3 = super::encrypt_failure_packet(
1586                         onion_keys[2].shared_secret.as_ref(),
1587                         &onion_packet_2.data[..],
1588                 );
1589                 let hex = "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";
1590                 assert_eq!(onion_packet_3.data, <Vec<u8>>::from_hex(hex).unwrap());
1591
1592                 let onion_packet_4 = super::encrypt_failure_packet(
1593                         onion_keys[1].shared_secret.as_ref(),
1594                         &onion_packet_3.data[..],
1595                 );
1596                 let hex = "aac3200c4968f56b21f53e5e374e3a2383ad2b1b6501bbcc45abc31e59b26881b7dfadbb56ec8dae8857add94e6702fb4c3a4de22e2e669e1ed926b04447fc73034bb730f4932acd62727b75348a648a1128744657ca6a4e713b9b646c3ca66cac02cdab44dd3439890ef3aaf61708714f7375349b8da541b2548d452d84de7084bb95b3ac2345201d624d31f4d52078aa0fa05a88b4e20202bd2b86ac5b52919ea305a8949de95e935eed0319cf3cf19ebea61d76ba92532497fcdc9411d06bcd4275094d0a4a3c5d3a945e43305a5a9256e333e1f64dbca5fcd4e03a39b9012d197506e06f29339dfee3331995b21615337ae060233d39befea925cc262873e0530408e6990f1cbd233a150ef7b004ff6166c70c68d9f8c853c1abca640b8660db2921";
1597                 assert_eq!(onion_packet_4.data, <Vec<u8>>::from_hex(hex).unwrap());
1598
1599                 let onion_packet_5 = super::encrypt_failure_packet(
1600                         onion_keys[0].shared_secret.as_ref(),
1601                         &onion_packet_4.data[..],
1602                 );
1603                 let hex = "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";
1604                 assert_eq!(onion_packet_5.data, <Vec<u8>>::from_hex(hex).unwrap());
1605         }
1606
1607         struct RawOnionHopData {
1608                 data: Vec<u8>,
1609         }
1610         impl RawOnionHopData {
1611                 fn new(orig: msgs::OutboundOnionPayload) -> Self {
1612                         Self { data: orig.encode() }
1613                 }
1614         }
1615         impl Writeable for RawOnionHopData {
1616                 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
1617                         writer.write_all(&self.data[..])
1618                 }
1619         }
1620 }