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