_ 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::crypto::chacha20::ChaCha20;
  11 use crate::crypto::streams::ChaChaReader;
  12 use crate::ln::channelmanager::{HTLCSource, RecipientOnionFields};
  13 use crate::ln::msgs;
  14 use crate::ln::wire::Encode;
  15 use crate::ln::{PaymentHash, PaymentPreimage};
  16 use crate::routing::gossip::NetworkUpdate;
  17 use crate::routing::router::{BlindedTail, Path, RouteHop};
  18 use crate::sign::NodeSigner;
  19 use crate::util::errors::{self, APIError};
  20 use crate::util::logger::Logger;
  21 use crate::util::ser::{LengthCalculatingWriter, Readable, ReadableArgs, Writeable, Writer};
  22
  23 use bitcoin::hashes::cmp::fixed_time_eq;
  24 use bitcoin::hashes::hmac::{Hmac, HmacEngine};
  25 use bitcoin::hashes::sha256::Hash as Sha256;
  26 use bitcoin::hashes::{Hash, HashEngine};
  27
  28 use bitcoin::secp256k1;
  29 use bitcoin::secp256k1::ecdh::SharedSecret;
  30 use bitcoin::secp256k1::{PublicKey, Scalar, Secp256k1, SecretKey};
  31
  32 use crate::io::{Cursor, Read};
  33 use crate::prelude::*;
  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
 122                 .blinded_tail
 123                 .as_ref()
 124                 .map(|t| t.hops.iter())
 125                 .unwrap_or([].iter())
 126                 .skip(1) // Skip the intro node because it's included in the unblinded hops
 127                 .map(|h| (&h.blinded_node_id, None));
 128         for (idx, (pubkey, route_hop_opt)) in unblinded_hops_iter.chain(blinded_pks_iter).enumerate() {
 129                 let shared_secret = SharedSecret::new(pubkey, &blinded_priv);
 130
 131                 let mut sha = Sha256::engine();
 132                 sha.input(&blinded_pub.serialize()[..]);
 133                 sha.input(shared_secret.as_ref());
 134                 let blinding_factor = Sha256::from_engine(sha).to_byte_array();
 135
 136                 let ephemeral_pubkey = blinded_pub;
 137
 138                 blinded_priv = blinded_priv.mul_tweak(&Scalar::from_be_bytes(blinding_factor).unwrap())?;
 139                 blinded_pub = PublicKey::from_secret_key(secp_ctx, &blinded_priv);
 140
 141                 callback(shared_secret, blinding_factor, ephemeral_pubkey, route_hop_opt, idx);
 142         }
 143
 144         Ok(())
 145 }
 146
 147 // can only fail if an intermediary hop has an invalid public key or session_priv is invalid
 148 pub(super) fn construct_onion_keys<T: secp256k1::Signing>(
 149         secp_ctx: &Secp256k1<T>, path: &Path, session_priv: &SecretKey,
 150 ) -> Result<Vec<OnionKeys>, secp256k1::Error> {
 151         let mut res = Vec::with_capacity(path.hops.len());
 152
 153         construct_onion_keys_callback(
 154                 secp_ctx,
 155                 &path,
 156                 session_priv,
 157                 |shared_secret, _blinding_factor, ephemeral_pubkey, _, _| {
 158                         let (rho, mu) = gen_rho_mu_from_shared_secret(shared_secret.as_ref());
 159
 160                         res.push(OnionKeys {
 161                                 #[cfg(test)]
 162                                 shared_secret,
 163                                 #[cfg(test)]
 164                                 blinding_factor: _blinding_factor,
 165                                 ephemeral_pubkey,
 166                                 rho,
 167                                 mu,
 168                         });
 169                 },
 170         )?;
 171
 172         Ok(res)
 173 }
 174
 175 /// returns the hop data, as well as the first-hop value_msat and CLTV value we should send.
 176 pub(super) fn build_onion_payloads(
 177         path: &Path, total_msat: u64, mut recipient_onion: RecipientOnionFields,
 178         starting_htlc_offset: u32, keysend_preimage: &Option<PaymentPreimage>,
 179 ) -> Result<(Vec<msgs::OutboundOnionPayload>, u64, u32), APIError> {
 180         let mut cur_value_msat = 0u64;
 181         let mut cur_cltv = starting_htlc_offset;
 182         let mut last_short_channel_id = 0;
 183         let mut res: Vec<msgs::OutboundOnionPayload> = Vec::with_capacity(
 184                 path.hops.len() + path.blinded_tail.as_ref().map_or(0, |t| t.hops.len()),
 185         );
 186
 187         for (idx, hop) in path.hops.iter().rev().enumerate() {
 188                 // First hop gets special values so that it can check, on receipt, that everything is
 189                 // exactly as it should be (and the next hop isn't trying to probe to find out if we're
 190                 // the intended recipient).
 191                 let value_msat = if cur_value_msat == 0 { hop.fee_msat } else { cur_value_msat };
 192                 let cltv = if cur_cltv == starting_htlc_offset {
 193                         hop.cltv_expiry_delta + starting_htlc_offset
 194                 } else {
 195                         cur_cltv
 196                 };
 197                 if idx == 0 {
 198                         if let Some(BlindedTail {
 199                                 blinding_point,
 200                                 hops,
 201                                 final_value_msat,
 202                                 excess_final_cltv_expiry_delta,
 203                                 ..
 204                         }) = &path.blinded_tail
 205                         {
 206                                 let mut blinding_point = Some(*blinding_point);
 207                                 for (i, blinded_hop) in hops.iter().enumerate() {
 208                                         if i == hops.len() - 1 {
 209                                                 cur_value_msat += final_value_msat;
 210                                                 res.push(msgs::OutboundOnionPayload::BlindedReceive {
 211                                                         sender_intended_htlc_amt_msat: *final_value_msat,
 212                                                         total_msat,
 213                                                         cltv_expiry_height: cur_cltv + excess_final_cltv_expiry_delta,
 214                                                         encrypted_tlvs: blinded_hop.encrypted_payload.clone(),
 215                                                         intro_node_blinding_point: blinding_point.take(),
 216                                                         keysend_preimage: *keysend_preimage,
 217                                                 });
 218                                         } else {
 219                                                 res.push(msgs::OutboundOnionPayload::BlindedForward {
 220                                                         encrypted_tlvs: blinded_hop.encrypted_payload.clone(),
 221                                                         intro_node_blinding_point: blinding_point.take(),
 222                                                 });
 223                                         }
 224                                 }
 225                         } else {
 226                                 res.push(msgs::OutboundOnionPayload::Receive {
 227                                         payment_data: if let Some(secret) = recipient_onion.payment_secret.take() {
 228                                                 Some(msgs::FinalOnionHopData { payment_secret: secret, total_msat })
 229                                         } else {
 230                                                 None
 231                                         },
 232                                         payment_metadata: recipient_onion.payment_metadata.take(),
 233                                         keysend_preimage: *keysend_preimage,
 234                                         custom_tlvs: recipient_onion.custom_tlvs.clone(),
 235                                         sender_intended_htlc_amt_msat: value_msat,
 236                                         cltv_expiry_height: cltv,
 237                                 });
 238                         }
 239                 } else {
 240                         let payload = msgs::OutboundOnionPayload::Forward {
 241                                 short_channel_id: last_short_channel_id,
 242                                 amt_to_forward: value_msat,
 243                                 outgoing_cltv_value: cltv,
 244                         };
 245                         res.insert(0, payload);
 246                 }
 247                 cur_value_msat += hop.fee_msat;
 248                 if cur_value_msat >= 21000000 * 100000000 * 1000 {
 249                         return Err(APIError::InvalidRoute { err: "Channel fees overflowed?".to_owned() });
 250                 }
 251                 cur_cltv += hop.cltv_expiry_delta as u32;
 252                 if cur_cltv >= 500000000 {
 253                         return Err(APIError::InvalidRoute { err: "Channel CLTV overflowed?".to_owned() });
 254                 }
 255                 last_short_channel_id = hop.short_channel_id;
 256         }
 257         Ok((res, cur_value_msat, cur_cltv))
 258 }
 259
 260 /// Length of the onion data packet. Before TLV-based onions this was 20 65-byte hops, though now
 261 /// the hops can be of variable length.
 262 pub(crate) const ONION_DATA_LEN: usize = 20 * 65;
 263
 264 pub(super) const INVALID_ONION_BLINDING: u16 = 0x8000 | 0x4000 | 24;
 265
 266 #[inline]
 267 fn shift_slice_right(arr: &mut [u8], amt: usize) {
 268         for i in (amt..arr.len()).rev() {
 269                 arr[i] = arr[i - amt];
 270         }
 271         for i in 0..amt {
 272                 arr[i] = 0;
 273         }
 274 }
 275
 276 pub(super) fn construct_onion_packet(
 277         payloads: Vec<msgs::OutboundOnionPayload>, onion_keys: Vec<OnionKeys>, prng_seed: [u8; 32],
 278         associated_data: &PaymentHash,
 279 ) -> Result<msgs::OnionPacket, ()> {
 280         let mut packet_data = [0; ONION_DATA_LEN];
 281
 282         let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
 283         chacha.process(&[0; ONION_DATA_LEN], &mut packet_data);
 284
 285         let packet = FixedSizeOnionPacket(packet_data);
 286         construct_onion_packet_with_init_noise::<_, _>(
 287                 payloads,
 288                 onion_keys,
 289                 packet,
 290                 Some(associated_data),
 291         )
 292 }
 293
 294 #[cfg(test)]
 295 /// Used in testing to write bogus `BogusOnionHopData` as well as `RawOnionHopData`, which is
 296 /// otherwise not representable in `msgs::OnionHopData`.
 297 pub(super) fn construct_onion_packet_with_writable_hopdata<HD: Writeable>(
 298         payloads: Vec<HD>, onion_keys: Vec<OnionKeys>, prng_seed: [u8; 32],
 299         associated_data: &PaymentHash,
 300 ) -> Result<msgs::OnionPacket, ()> {
 301         let mut packet_data = [0; ONION_DATA_LEN];
 302
 303         let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
 304         chacha.process(&[0; ONION_DATA_LEN], &mut packet_data);
 305
 306         let packet = FixedSizeOnionPacket(packet_data);
 307         construct_onion_packet_with_init_noise::<_, _>(
 308                 payloads,
 309                 onion_keys,
 310                 packet,
 311                 Some(associated_data),
 312         )
 313 }
 314
 315 /// Since onion message packets and onion payment packets have different lengths but are otherwise
 316 /// identical, we use this trait to allow `construct_onion_packet_with_init_noise` to return either
 317 /// type.
 318 pub(crate) trait Packet {
 319         type Data: AsMut<[u8]>;
 320         fn new(pubkey: PublicKey, hop_data: Self::Data, hmac: [u8; 32]) -> Self;
 321 }
 322
 323 // Needed for rustc versions older than 1.47 to avoid E0277: "arrays only have std trait
 324 // implementations for lengths 0..=32".
 325 pub(crate) struct FixedSizeOnionPacket(pub(crate) [u8; ONION_DATA_LEN]);
 326
 327 impl AsMut<[u8]> for FixedSizeOnionPacket {
 328         fn as_mut(&mut self) -> &mut [u8] {
 329                 &mut self.0
 330         }
 331 }
 332
 333 pub(crate) fn payloads_serialized_length<HD: Writeable>(payloads: &Vec<HD>) -> usize {
 334         payloads.iter().map(|p| p.serialized_length() + 32 /* HMAC */).sum()
 335 }
 336
 337 pub(crate) fn construct_onion_message_packet<HD: Writeable, P: Packet<Data = Vec<u8>>>(
 338         payloads: Vec<HD>, onion_keys: Vec<OnionKeys>, prng_seed: [u8; 32], packet_data_len: usize,
 339 ) -> Result<P, ()> {
 340         let mut packet_data = vec![0; packet_data_len];
 341
 342         let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
 343         chacha.process_in_place(&mut packet_data);
 344
 345         construct_onion_packet_with_init_noise::<_, _>(payloads, onion_keys, packet_data, None)
 346 }
 347
 348 fn construct_onion_packet_with_init_noise<HD: Writeable, P: Packet>(
 349         mut payloads: Vec<HD>, onion_keys: Vec<OnionKeys>, mut packet_data: P::Data,
 350         associated_data: Option<&PaymentHash>,
 351 ) -> Result<P, ()> {
 352         let filler = {
 353                 let packet_data = packet_data.as_mut();
 354                 const ONION_HOP_DATA_LEN: usize = 65; // We may decrease this eventually after TLV is common
 355                 let mut res = Vec::with_capacity(ONION_HOP_DATA_LEN * (payloads.len() - 1));
 356
 357                 let mut pos = 0;
 358                 for (i, (payload, keys)) in payloads.iter().zip(onion_keys.iter()).enumerate() {
 359                         let mut chacha = ChaCha20::new(&keys.rho, &[0u8; 8]);
 360                         // TODO: Batch this.
 361                         for _ in 0..(packet_data.len() - pos) {
 362                                 let mut dummy = [0; 1];
 363                                 chacha.process_in_place(&mut dummy); // We don't have a seek function :(
 364                         }
 365
 366                         let mut payload_len = LengthCalculatingWriter(0);
 367                         payload.write(&mut payload_len).expect("Failed to calculate length");
 368                         pos += payload_len.0 + 32;
 369                         if pos > packet_data.len() {
 370                                 return Err(());
 371                         }
 372
 373                         if i == payloads.len() - 1 {
 374                                 break;
 375                         }
 376
 377                         res.resize(pos, 0u8);
 378                         chacha.process_in_place(&mut res);
 379                 }
 380                 res
 381         };
 382
 383         let mut hmac_res = [0; 32];
 384         for (i, (payload, keys)) in payloads.iter_mut().zip(onion_keys.iter()).rev().enumerate() {
 385                 let mut payload_len = LengthCalculatingWriter(0);
 386                 payload.write(&mut payload_len).expect("Failed to calculate length");
 387
 388                 let packet_data = packet_data.as_mut();
 389                 shift_slice_right(packet_data, payload_len.0 + 32);
 390                 packet_data[0..payload_len.0].copy_from_slice(&payload.encode()[..]);
 391                 packet_data[payload_len.0..(payload_len.0 + 32)].copy_from_slice(&hmac_res);
 392
 393                 let mut chacha = ChaCha20::new(&keys.rho, &[0u8; 8]);
 394                 chacha.process_in_place(packet_data);
 395
 396                 if i == 0 {
 397                         let stop_index = packet_data.len();
 398                         let start_index = stop_index.checked_sub(filler.len()).ok_or(())?;
 399                         packet_data[start_index..stop_index].copy_from_slice(&filler[..]);
 400                 }
 401
 402                 let mut hmac = HmacEngine::<Sha256>::new(&keys.mu);
 403                 hmac.input(packet_data);
 404                 if let Some(associated_data) = associated_data {
 405                         hmac.input(&associated_data.0[..]);
 406                 }
 407                 hmac_res = Hmac::from_engine(hmac).to_byte_array();
 408         }
 409
 410         Ok(P::new(onion_keys.first().unwrap().ephemeral_pubkey, packet_data, hmac_res))
 411 }
 412
 413 /// Encrypts a failure packet. raw_packet can either be a
 414 /// msgs::DecodedOnionErrorPacket.encode() result or a msgs::OnionErrorPacket.data element.
 415 pub(super) fn encrypt_failure_packet(
 416         shared_secret: &[u8], raw_packet: &[u8],
 417 ) -> msgs::OnionErrorPacket {
 418         let ammag = gen_ammag_from_shared_secret(&shared_secret);
 419
 420         let mut packet_crypted = Vec::with_capacity(raw_packet.len());
 421         packet_crypted.resize(raw_packet.len(), 0);
 422         let mut chacha = ChaCha20::new(&ammag, &[0u8; 8]);
 423         chacha.process(&raw_packet, &mut packet_crypted[..]);
 424         msgs::OnionErrorPacket { data: packet_crypted }
 425 }
 426
 427 pub(super) fn build_failure_packet(
 428         shared_secret: &[u8], failure_type: u16, failure_data: &[u8],
 429 ) -> msgs::DecodedOnionErrorPacket {
 430         assert_eq!(shared_secret.len(), 32);
 431         assert!(failure_data.len() <= 256 - 2);
 432
 433         let um = gen_um_from_shared_secret(&shared_secret);
 434
 435         let failuremsg = {
 436                 let mut res = Vec::with_capacity(2 + failure_data.len());
 437                 res.push(((failure_type >> 8) & 0xff) as u8);
 438                 res.push(((failure_type >> 0) & 0xff) as u8);
 439                 res.extend_from_slice(&failure_data[..]);
 440                 res
 441         };
 442         let pad = {
 443                 let mut res = Vec::with_capacity(256 - 2 - failure_data.len());
 444                 res.resize(256 - 2 - failure_data.len(), 0);
 445                 res
 446         };
 447         let mut packet = msgs::DecodedOnionErrorPacket { hmac: [0; 32], failuremsg, pad };
 448
 449         let mut hmac = HmacEngine::<Sha256>::new(&um);
 450         hmac.input(&packet.encode()[32..]);
 451         packet.hmac = Hmac::from_engine(hmac).to_byte_array();
 452
 453         packet
 454 }
 455
 456 #[cfg(test)]
 457 pub(super) fn build_first_hop_failure_packet(
 458         shared_secret: &[u8], failure_type: u16, failure_data: &[u8],
 459 ) -> msgs::OnionErrorPacket {
 460         let failure_packet = build_failure_packet(shared_secret, failure_type, failure_data);
 461         encrypt_failure_packet(shared_secret, &failure_packet.encode()[..])
 462 }
 463
 464 pub(crate) struct DecodedOnionFailure {
 465         pub(crate) network_update: Option<NetworkUpdate>,
 466         pub(crate) short_channel_id: Option<u64>,
 467         pub(crate) payment_failed_permanently: bool,
 468         pub(crate) failed_within_blinded_path: bool,
 469         #[cfg(test)]
 470         pub(crate) onion_error_code: Option<u16>,
 471         #[cfg(test)]
 472         pub(crate) onion_error_data: Option<Vec<u8>>,
 473 }
 474
 475 /// Note that we always decrypt `packet` in-place here even if the deserialization into
 476 /// [`msgs::DecodedOnionErrorPacket`] ultimately fails.
 477 fn decrypt_onion_error_packet(
 478         packet: &mut Vec<u8>, shared_secret: SharedSecret,
 479 ) -> Result<msgs::DecodedOnionErrorPacket, msgs::DecodeError> {
 480         let ammag = gen_ammag_from_shared_secret(shared_secret.as_ref());
 481         let mut chacha = ChaCha20::new(&ammag, &[0u8; 8]);
 482         chacha.process_in_place(packet);
 483         msgs::DecodedOnionErrorPacket::read(&mut Cursor::new(packet))
 484 }
 485
 486 /// Process failure we got back from upstream on a payment we sent (implying htlc_source is an
 487 /// OutboundRoute).
 488 #[inline]
 489 pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
 490         secp_ctx: &Secp256k1<T>, logger: &L, htlc_source: &HTLCSource, mut encrypted_packet: Vec<u8>,
 491 ) -> DecodedOnionFailure
 492 where
 493         L::Target: Logger,
 494 {
 495         let (path, session_priv, first_hop_htlc_msat) = match htlc_source {
 496                 HTLCSource::OutboundRoute {
 497                         ref path, ref session_priv, ref first_hop_htlc_msat, ..
 498                 } => (path, session_priv, first_hop_htlc_msat),
 499                 _ => {
 500                         unreachable!()
 501                 },
 502         };
 503
 504         // Learnings from the HTLC failure to inform future payment retries and scoring.
 505         struct FailureLearnings {
 506                 network_update: Option<NetworkUpdate>,
 507                 short_channel_id: Option<u64>,
 508                 payment_failed_permanently: bool,
 509                 failed_within_blinded_path: bool,
 510         }
 511         let mut res: Option<FailureLearnings> = None;
 512         let mut htlc_msat = *first_hop_htlc_msat;
 513         let mut error_code_ret = None;
 514         let mut error_packet_ret = None;
 515         let mut is_from_final_node = false;
 516
 517         const BADONION: u16 = 0x8000;
 518         const PERM: u16 = 0x4000;
 519         const NODE: u16 = 0x2000;
 520         const UPDATE: u16 = 0x1000;
 521
 522         // Handle packed channel/node updates for passing back for the route handler
 523         let callback = |shared_secret, _, _, route_hop_opt: Option<&RouteHop>, route_hop_idx| {
 524                 if res.is_some() {
 525                         return;
 526                 }
 527
 528                 let route_hop = match route_hop_opt {
 529                         Some(hop) => hop,
 530                         None => {
 531                                 // Got an error from within a blinded route.
 532                                 error_code_ret = Some(BADONION | PERM | 24); // invalid_onion_blinding
 533                                 error_packet_ret = Some(vec![0; 32]);
 534                                 res = Some(FailureLearnings {
 535                                         network_update: None,
 536                                         short_channel_id: None,
 537                                         payment_failed_permanently: false,
 538                                         failed_within_blinded_path: true,
 539                                 });
 540                                 return;
 541                         },
 542                 };
 543
 544                 // The failing hop includes either the inbound channel to the recipient or the outbound channel
 545                 // from the current hop (i.e., the next hop's inbound channel).
 546                 let num_blinded_hops = path.blinded_tail.as_ref().map_or(0, |bt| bt.hops.len());
 547                 // For 1-hop blinded paths, the final `path.hops` entry is the recipient.
 548                 is_from_final_node = route_hop_idx + 1 == path.hops.len() && num_blinded_hops <= 1;
 549                 let failing_route_hop = if is_from_final_node {
 550                         route_hop
 551                 } else {
 552                         match path.hops.get(route_hop_idx + 1) {
 553                                 Some(hop) => hop,
 554                                 None => {
 555                                         // The failing hop is within a multi-hop blinded path.
 556                                         #[cfg(not(test))]
 557                                         {
 558                                                 error_code_ret = Some(BADONION | PERM | 24); // invalid_onion_blinding
 559                                                 error_packet_ret = Some(vec![0; 32]);
 560                                         }
 561                                         #[cfg(test)]
 562                                         {
 563                                                 // Actually parse the onion error data in tests so we can check that blinded hops fail
 564                                                 // back correctly.
 565                                                 let err_packet =
 566                                                         decrypt_onion_error_packet(&mut encrypted_packet, shared_secret)
 567                                                                 .unwrap();
 568                                                 error_code_ret = Some(u16::from_be_bytes(
 569                                                         err_packet.failuremsg.get(0..2).unwrap().try_into().unwrap(),
 570                                                 ));
 571                                                 error_packet_ret = Some(err_packet.failuremsg[2..].to_vec());
 572                                         }
 573
 574                                         res = Some(FailureLearnings {
 575                                                 network_update: None,
 576                                                 short_channel_id: None,
 577                                                 payment_failed_permanently: false,
 578                                                 failed_within_blinded_path: true,
 579                                         });
 580                                         return;
 581                                 },
 582                         }
 583                 };
 584
 585                 let amt_to_forward = htlc_msat - route_hop.fee_msat;
 586                 htlc_msat = amt_to_forward;
 587
 588                 let err_packet = match decrypt_onion_error_packet(&mut encrypted_packet, shared_secret) {
 589                         Ok(p) => p,
 590                         Err(_) => return,
 591                 };
 592                 let um = gen_um_from_shared_secret(shared_secret.as_ref());
 593                 let mut hmac = HmacEngine::<Sha256>::new(&um);
 594                 hmac.input(&err_packet.encode()[32..]);
 595
 596                 if !fixed_time_eq(&Hmac::from_engine(hmac).to_byte_array(), &err_packet.hmac) {
 597                         return;
 598                 }
 599                 let error_code_slice = match err_packet.failuremsg.get(0..2) {
 600                         Some(s) => s,
 601                         None => {
 602                                 // Useless packet that we can't use but it passed HMAC, so it definitely came from the peer
 603                                 // in question
 604                                 let network_update = Some(NetworkUpdate::NodeFailure {
 605                                         node_id: route_hop.pubkey,
 606                                         is_permanent: true,
 607                                 });
 608                                 let short_channel_id = Some(route_hop.short_channel_id);
 609                                 res = Some(FailureLearnings {
 610                                         network_update,
 611                                         short_channel_id,
 612                                         payment_failed_permanently: is_from_final_node,
 613                                         failed_within_blinded_path: false,
 614                                 });
 615                                 return;
 616                         },
 617                 };
 618
 619                 let error_code = u16::from_be_bytes(error_code_slice.try_into().expect("len is 2"));
 620                 error_code_ret = Some(error_code);
 621                 error_packet_ret = Some(err_packet.failuremsg[2..].to_vec());
 622
 623                 let (debug_field, debug_field_size) = errors::get_onion_debug_field(error_code);
 624
 625                 // indicate that payment parameter has failed and no need to update Route object
 626                 let payment_failed = match error_code & 0xff {
 627                         15 | 16 | 17 | 18 | 19 | 23 => true,
 628                         _ => false,
 629                 } && is_from_final_node; // PERM bit observed below even if this error is from the intermediate nodes
 630
 631                 let mut network_update = None;
 632                 let mut short_channel_id = None;
 633
 634                 if error_code & BADONION == BADONION {
 635                         // If the error code has the BADONION bit set, always blame the channel from the node
 636                         // "originating" the error to its next hop. The "originator" is ultimately actually claiming
 637                         // that its counterparty is the one who is failing the HTLC.
 638                         // If the "originator" here isn't lying we should really mark the next-hop node as failed
 639                         // entirely, but we can't be confident in that, as it would allow any node to get us to
 640                         // completely ban one of its counterparties. Instead, we simply remove the channel in
 641                         // question.
 642                         network_update = Some(NetworkUpdate::ChannelFailure {
 643                                 short_channel_id: failing_route_hop.short_channel_id,
 644                                 is_permanent: true,
 645                         });
 646                 } else if error_code & NODE == NODE {
 647                         let is_permanent = error_code & PERM == PERM;
 648                         network_update =
 649                                 Some(NetworkUpdate::NodeFailure { node_id: route_hop.pubkey, is_permanent });
 650                         short_channel_id = Some(route_hop.short_channel_id);
 651                 } else if error_code & PERM == PERM {
 652                         if !payment_failed {
 653                                 network_update = Some(NetworkUpdate::ChannelFailure {
 654                                         short_channel_id: failing_route_hop.short_channel_id,
 655                                         is_permanent: true,
 656                                 });
 657                                 short_channel_id = Some(failing_route_hop.short_channel_id);
 658                         }
 659                 } else if error_code & UPDATE == UPDATE {
 660                         if let Some(update_len_slice) =
 661                                 err_packet.failuremsg.get(debug_field_size + 2..debug_field_size + 4)
 662                         {
 663                                 let update_len =
 664                                         u16::from_be_bytes(update_len_slice.try_into().expect("len is 2")) as usize;
 665                                 if let Some(mut update_slice) = err_packet
 666                                         .failuremsg
 667                                         .get(debug_field_size + 4..debug_field_size + 4 + update_len)
 668                                 {
 669                                         // Historically, the BOLTs were unclear if the message type
 670                                         // bytes should be included here or not. The BOLTs have now
 671                                         // been updated to indicate that they *are* included, but many
 672                                         // nodes still send messages without the type bytes, so we
 673                                         // support both here.
 674                                         // TODO: Switch to hard require the type prefix, as the current
 675                                         // permissiveness introduces the (although small) possibility
 676                                         // that we fail to decode legitimate channel updates that
 677                                         // happen to start with ChannelUpdate::TYPE, i.e., [0x01, 0x02].
 678                                         if update_slice.len() > 2
 679                                                 && update_slice[0..2] == msgs::ChannelUpdate::TYPE.to_be_bytes()
 680                                         {
 681                                                 update_slice = &update_slice[2..];
 682                                         } else {
 683                                                 log_trace!(logger, "Failure provided features a channel update without type prefix. Deprecated, but allowing for now.");
 684                                         }
 685                                         let update_opt = msgs::ChannelUpdate::read(&mut Cursor::new(&update_slice));
 686                                         if update_opt.is_ok() || update_slice.is_empty() {
 687                                                 // if channel_update should NOT have caused the failure:
 688                                                 // MAY treat the channel_update as invalid.
 689                                                 let is_chan_update_invalid = match error_code & 0xff {
 690                                                         7 => false,
 691                                                         11 => {
 692                                                                 update_opt.is_ok()
 693                                                                         && amt_to_forward
 694                                                                                 > update_opt.as_ref().unwrap().contents.htlc_minimum_msat
 695                                                         },
 696                                                         12 => {
 697                                                                 update_opt.is_ok()
 698                                                                         && amt_to_forward
 699                                                                                 .checked_mul(
 700                                                                                         update_opt
 701                                                                                                 .as_ref()
 702                                                                                                 .unwrap()
 703                                                                                                 .contents
 704                                                                                                 .fee_proportional_millionths as u64,
 705                                                                                 )
 706                                                                                 .map(|prop_fee| prop_fee / 1_000_000)
 707                                                                                 .and_then(|prop_fee| {
 708                                                                                         prop_fee.checked_add(
 709                                                                                                 update_opt.as_ref().unwrap().contents.fee_base_msat
 710                                                                                                         as u64,
 711                                                                                         )
 712                                                                                 })
 713                                                                                 .map(|fee_msats| route_hop.fee_msat >= fee_msats)
 714                                                                                 .unwrap_or(false)
 715                                                         },
 716                                                         13 => {
 717                                                                 update_opt.is_ok()
 718                                                                         && route_hop.cltv_expiry_delta as u16
 719                                                                                 >= update_opt.as_ref().unwrap().contents.cltv_expiry_delta
 720                                                         },
 721                                                         14 => false, // expiry_too_soon; always valid?
 722                                                         20 => update_opt.as_ref().unwrap().contents.flags & 2 == 0,
 723                                                         _ => false, // unknown error code; take channel_update as valid
 724                                                 };
 725                                                 if is_chan_update_invalid {
 726                                                         // This probably indicates the node which forwarded
 727                                                         // to the node in question corrupted something.
 728                                                         network_update = Some(NetworkUpdate::ChannelFailure {
 729                                                                 short_channel_id: route_hop.short_channel_id,
 730                                                                 is_permanent: true,
 731                                                         });
 732                                                 } else {
 733                                                         if let Ok(chan_update) = update_opt {
 734                                                                 // Make sure the ChannelUpdate contains the expected
 735                                                                 // short channel id.
 736                                                                 if failing_route_hop.short_channel_id
 737                                                                         == chan_update.contents.short_channel_id
 738                                                                 {
 739                                                                         short_channel_id = Some(failing_route_hop.short_channel_id);
 740                                                                 } else {
 741                                                                         log_info!(logger, "Node provided a channel_update for which it was not authoritative, ignoring.");
 742                                                                 }
 743                                                                 network_update =
 744                                                                         Some(NetworkUpdate::ChannelUpdateMessage { msg: chan_update })
 745                                                         } else {
 746                                                                 // The node in question intentionally encoded a 0-length channel update. This is
 747                                                                 // likely due to https://github.com/ElementsProject/lightning/issues/6200.
 748                                                                 short_channel_id = Some(failing_route_hop.short_channel_id);
 749                                                                 network_update = Some(NetworkUpdate::ChannelFailure {
 750                                                                         short_channel_id: failing_route_hop.short_channel_id,
 751                                                                         is_permanent: false,
 752                                                                 });
 753                                                         }
 754                                                 };
 755                                         } else {
 756                                                 // If the channel_update had a non-zero length (i.e. was
 757                                                 // present) but we couldn't read it, treat it as a total
 758                                                 // node failure.
 759                                                 log_info!(
 760                                                         logger,
 761                                                         "Failed to read a channel_update of len {} in an onion",
 762                                                         update_slice.len()
 763                                                 );
 764                                         }
 765                                 }
 766                         }
 767                         if network_update.is_none() {
 768                                 // They provided an UPDATE which was obviously bogus, not worth
 769                                 // trying to relay through them anymore.
 770                                 network_update = Some(NetworkUpdate::NodeFailure {
 771                                         node_id: route_hop.pubkey,
 772                                         is_permanent: true,
 773                                 });
 774                         }
 775                         if short_channel_id.is_none() {
 776                                 short_channel_id = Some(route_hop.short_channel_id);
 777                         }
 778                 } else if payment_failed {
 779                         // Only blame the hop when a value in the HTLC doesn't match the corresponding value in the
 780                         // onion.
 781                         short_channel_id = match error_code & 0xff {
 782                                 18 | 19 => Some(route_hop.short_channel_id),
 783                                 _ => None,
 784                         };
 785                 } else {
 786                         // We can't understand their error messages and they failed to forward...they probably can't
 787                         // understand our forwards so it's really not worth trying any further.
 788                         network_update =
 789                                 Some(NetworkUpdate::NodeFailure { node_id: route_hop.pubkey, is_permanent: true });
 790                         short_channel_id = Some(route_hop.short_channel_id);
 791                 }
 792
 793                 res = Some(FailureLearnings {
 794                         network_update,
 795                         short_channel_id,
 796                         payment_failed_permanently: error_code & PERM == PERM && is_from_final_node,
 797                         failed_within_blinded_path: false,
 798                 });
 799
 800                 let (description, title) = errors::get_onion_error_description(error_code);
 801                 if debug_field_size > 0 && err_packet.failuremsg.len() >= 4 + debug_field_size {
 802                         log_info!(
 803                                 logger,
 804                                 "Onion Error[from {}: {}({:#x}) {}({})] {}",
 805                                 route_hop.pubkey,
 806                                 title,
 807                                 error_code,
 808                                 debug_field,
 809                                 log_bytes!(&err_packet.failuremsg[4..4 + debug_field_size]),
 810                                 description
 811                         );
 812                 } else {
 813                         log_info!(
 814                                 logger,
 815                                 "Onion Error[from {}: {}({:#x})] {}",
 816                                 route_hop.pubkey,
 817                                 title,
 818                                 error_code,
 819                                 description
 820                         );
 821                 }
 822         };
 823
 824         construct_onion_keys_callback(secp_ctx, &path, session_priv, callback)
 825                 .expect("Route that we sent via spontaneously grew invalid keys in the middle of it?");
 826
 827         if let Some(FailureLearnings {
 828                 network_update,
 829                 short_channel_id,
 830                 payment_failed_permanently,
 831                 failed_within_blinded_path,
 832         }) = res
 833         {
 834                 DecodedOnionFailure {
 835                         network_update,
 836                         short_channel_id,
 837                         payment_failed_permanently,
 838                         failed_within_blinded_path,
 839                         #[cfg(test)]
 840                         onion_error_code: error_code_ret,
 841                         #[cfg(test)]
 842                         onion_error_data: error_packet_ret,
 843                 }
 844         } else {
 845                 // only not set either packet unparseable or hmac does not match with any
 846                 // payment not retryable only when garbage is from the final node
 847                 DecodedOnionFailure {
 848                         network_update: None,
 849                         short_channel_id: None,
 850                         payment_failed_permanently: is_from_final_node,
 851                         failed_within_blinded_path: false,
 852                         #[cfg(test)]
 853                         onion_error_code: None,
 854                         #[cfg(test)]
 855                         onion_error_data: None,
 856                 }
 857         }
 858 }
 859
 860 #[derive(Clone)] // See Channel::revoke_and_ack for why, tl;dr: Rust bug
 861 #[cfg_attr(test, derive(PartialEq))]
 862 pub(super) struct HTLCFailReason(HTLCFailReasonRepr);
 863
 864 #[derive(Clone)] // See Channel::revoke_and_ack for why, tl;dr: Rust bug
 865 #[cfg_attr(test, derive(PartialEq))]
 866 enum HTLCFailReasonRepr {
 867         LightningError { err: msgs::OnionErrorPacket },
 868         Reason { failure_code: u16, data: Vec<u8> },
 869 }
 870
 871 impl core::fmt::Debug for HTLCFailReason {
 872         fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
 873                 match self.0 {
 874                         HTLCFailReasonRepr::Reason { ref failure_code, .. } => {
 875                                 write!(f, "HTLC error code {}", failure_code)
 876                         },
 877                         HTLCFailReasonRepr::LightningError { .. } => {
 878                                 write!(f, "pre-built LightningError")
 879                         },
 880                 }
 881         }
 882 }
 883
 884 impl Writeable for HTLCFailReason {
 885         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), crate::io::Error> {
 886                 self.0.write(writer)
 887         }
 888 }
 889 impl Readable for HTLCFailReason {
 890         fn read<R: Read>(reader: &mut R) -> Result<Self, msgs::DecodeError> {
 891                 Ok(Self(Readable::read(reader)?))
 892         }
 893 }
 894
 895 impl_writeable_tlv_based_enum!(HTLCFailReasonRepr,
 896         (0, LightningError) => {
 897                 (0, err, required),
 898         },
 899         (1, Reason) => {
 900                 (0, failure_code, required),
 901                 (2, data, required_vec),
 902         },
 903 ;);
 904
 905 impl HTLCFailReason {
 906         #[rustfmt::skip]
 907         pub(super) fn reason(failure_code: u16, data: Vec<u8>) -> Self {
 908                 const BADONION: u16 = 0x8000;
 909                 const PERM: u16 = 0x4000;
 910                 const NODE: u16 = 0x2000;
 911                 const UPDATE: u16 = 0x1000;
 912
 913                      if failure_code == 1  | PERM { debug_assert!(data.is_empty()) }
 914                 else if failure_code == 2  | NODE { debug_assert!(data.is_empty()) }
 915                 else if failure_code == 2  | PERM | NODE { debug_assert!(data.is_empty()) }
 916                 else if failure_code == 3  | PERM | NODE { debug_assert!(data.is_empty()) }
 917                 else if failure_code == 4  | BADONION | PERM { debug_assert_eq!(data.len(), 32) }
 918                 else if failure_code == 5  | BADONION | PERM { debug_assert_eq!(data.len(), 32) }
 919                 else if failure_code == 6  | BADONION | PERM { debug_assert_eq!(data.len(), 32) }
 920                 else if failure_code == 7  | UPDATE {
 921                         debug_assert_eq!(data.len() - 2, u16::from_be_bytes(data[0..2].try_into().unwrap()) as usize) }
 922                 else if failure_code == 8  | PERM { debug_assert!(data.is_empty()) }
 923                 else if failure_code == 9  | PERM { debug_assert!(data.is_empty()) }
 924                 else if failure_code == 10 | PERM { debug_assert!(data.is_empty()) }
 925                 else if failure_code == 11 | UPDATE {
 926                         debug_assert_eq!(data.len() - 2 - 8, u16::from_be_bytes(data[8..10].try_into().unwrap()) as usize) }
 927                 else if failure_code == 12 | UPDATE {
 928                         debug_assert_eq!(data.len() - 2 - 8, u16::from_be_bytes(data[8..10].try_into().unwrap()) as usize) }
 929                 else if failure_code == 13 | UPDATE {
 930                         debug_assert_eq!(data.len() - 2 - 4, u16::from_be_bytes(data[4..6].try_into().unwrap()) as usize) }
 931                 else if failure_code == 14 | UPDATE {
 932                         debug_assert_eq!(data.len() - 2, u16::from_be_bytes(data[0..2].try_into().unwrap()) as usize) }
 933                 else if failure_code == 15 | PERM { debug_assert_eq!(data.len(), 12) }
 934                 else if failure_code == 18 { debug_assert_eq!(data.len(), 4) }
 935                 else if failure_code == 19 { debug_assert_eq!(data.len(), 8) }
 936                 else if failure_code == 20 | UPDATE {
 937                         debug_assert_eq!(data.len() - 2 - 2, u16::from_be_bytes(data[2..4].try_into().unwrap()) as usize) }
 938                 else if failure_code == 21 { debug_assert!(data.is_empty()) }
 939                 else if failure_code == 22 | PERM { debug_assert!(data.len() <= 11) }
 940                 else if failure_code == 23 { debug_assert!(data.is_empty()) }
 941                 else if failure_code & BADONION != 0 {
 942                         // We set some bogus BADONION failure codes in test, so ignore unknown ones.
 943                 }
 944                 else { debug_assert!(false, "Unknown failure code: {}", failure_code) }
 945
 946                 Self(HTLCFailReasonRepr::Reason { failure_code, data })
 947         }
 948
 949         pub(super) fn from_failure_code(failure_code: u16) -> Self {
 950                 Self::reason(failure_code, Vec::new())
 951         }
 952
 953         pub(super) fn from_msg(msg: &msgs::UpdateFailHTLC) -> Self {
 954                 Self(HTLCFailReasonRepr::LightningError { err: msg.reason.clone() })
 955         }
 956
 957         pub(super) fn get_encrypted_failure_packet(
 958                 &self, incoming_packet_shared_secret: &[u8; 32], phantom_shared_secret: &Option<[u8; 32]>,
 959         ) -> msgs::OnionErrorPacket {
 960                 match self.0 {
 961                         HTLCFailReasonRepr::Reason { ref failure_code, ref data } => {
 962                                 if let Some(phantom_ss) = phantom_shared_secret {
 963                                         let phantom_packet =
 964                                                 build_failure_packet(phantom_ss, *failure_code, &data[..]).encode();
 965                                         let encrypted_phantom_packet =
 966                                                 encrypt_failure_packet(phantom_ss, &phantom_packet);
 967                                         encrypt_failure_packet(
 968                                                 incoming_packet_shared_secret,
 969                                                 &encrypted_phantom_packet.data[..],
 970                                         )
 971                                 } else {
 972                                         let packet = build_failure_packet(
 973                                                 incoming_packet_shared_secret,
 974                                                 *failure_code,
 975                                                 &data[..],
 976                                         )
 977                                         .encode();
 978                                         encrypt_failure_packet(incoming_packet_shared_secret, &packet)
 979                                 }
 980                         },
 981                         HTLCFailReasonRepr::LightningError { ref err } => {
 982                                 encrypt_failure_packet(incoming_packet_shared_secret, &err.data)
 983                         },
 984                 }
 985         }
 986
 987         pub(super) fn decode_onion_failure<T: secp256k1::Signing, L: Deref>(
 988                 &self, secp_ctx: &Secp256k1<T>, logger: &L, htlc_source: &HTLCSource,
 989         ) -> DecodedOnionFailure
 990         where
 991                 L::Target: Logger,
 992         {
 993                 match self.0 {
 994                         HTLCFailReasonRepr::LightningError { ref err } => {
 995                                 process_onion_failure(secp_ctx, logger, &htlc_source, err.data.clone())
 996                         },
 997                         #[allow(unused)]
 998                         HTLCFailReasonRepr::Reason { ref failure_code, ref data, .. } => {
 999                                 // we get a fail_malformed_htlc from the first hop
1000                                 // TODO: We'd like to generate a NetworkUpdate for temporary
1001                                 // failures here, but that would be insufficient as find_route
1002                                 // generally ignores its view of our own channels as we provide them via
1003                                 // ChannelDetails.
1004                                 if let &HTLCSource::OutboundRoute { ref path, .. } = htlc_source {
1005                                         DecodedOnionFailure {
1006                                                 network_update: None,
1007                                                 payment_failed_permanently: false,
1008                                                 short_channel_id: Some(path.hops[0].short_channel_id),
1009                                                 failed_within_blinded_path: false,
1010                                                 #[cfg(test)]
1011                                                 onion_error_code: Some(*failure_code),
1012                                                 #[cfg(test)]
1013                                                 onion_error_data: Some(data.clone()),
1014                                         }
1015                                 } else {
1016                                         unreachable!();
1017                                 }
1018                         },
1019                 }
1020         }
1021 }
1022
1023 /// Allows `decode_next_hop` to return the next hop packet bytes for either payments or onion
1024 /// message forwards.
1025 pub(crate) trait NextPacketBytes: AsMut<[u8]> {
1026         fn new(len: usize) -> Self;
1027 }
1028
1029 impl NextPacketBytes for FixedSizeOnionPacket {
1030         fn new(_len: usize) -> Self {
1031                 Self([0 as u8; ONION_DATA_LEN])
1032         }
1033 }
1034
1035 impl NextPacketBytes for Vec<u8> {
1036         fn new(len: usize) -> Self {
1037                 vec![0 as u8; len]
1038         }
1039 }
1040
1041 /// Data decrypted from a payment's onion payload.
1042 pub(crate) enum Hop {
1043         /// This onion payload was for us, not for forwarding to a next-hop. Contains information for
1044         /// verifying the incoming payment.
1045         Receive(msgs::InboundOnionPayload),
1046         /// This onion payload needs to be forwarded to a next-hop.
1047         Forward {
1048                 /// Onion payload data used in forwarding the payment.
1049                 next_hop_data: msgs::InboundOnionPayload,
1050                 /// HMAC of the next hop's onion packet.
1051                 next_hop_hmac: [u8; 32],
1052                 /// Bytes of the onion packet we're forwarding.
1053                 new_packet_bytes: [u8; ONION_DATA_LEN],
1054         },
1055 }
1056
1057 /// Error returned when we fail to decode the onion packet.
1058 #[derive(Debug)]
1059 pub(crate) enum OnionDecodeErr {
1060         /// The HMAC of the onion packet did not match the hop data.
1061         Malformed { err_msg: &'static str, err_code: u16 },
1062         /// We failed to decode the onion payload.
1063         Relay { err_msg: &'static str, err_code: u16 },
1064 }
1065
1066 pub(crate) fn decode_next_payment_hop<NS: Deref>(
1067         shared_secret: [u8; 32], hop_data: &[u8], hmac_bytes: [u8; 32], payment_hash: PaymentHash,
1068         blinding_point: Option<PublicKey>, node_signer: &NS,
1069 ) -> Result<Hop, OnionDecodeErr>
1070 where
1071         NS::Target: NodeSigner,
1072 {
1073         match decode_next_hop(
1074                 shared_secret,
1075                 hop_data,
1076                 hmac_bytes,
1077                 Some(payment_hash),
1078                 (blinding_point, node_signer),
1079         ) {
1080                 Ok((next_hop_data, None)) => Ok(Hop::Receive(next_hop_data)),
1081                 Ok((next_hop_data, Some((next_hop_hmac, FixedSizeOnionPacket(new_packet_bytes))))) => {
1082                         Ok(Hop::Forward { next_hop_data, next_hop_hmac, new_packet_bytes })
1083                 },
1084                 Err(e) => Err(e),
1085         }
1086 }
1087
1088 /// Build a payment onion, returning the first hop msat and cltv values as well.
1089 /// `cur_block_height` should be set to the best known block height + 1.
1090 pub fn create_payment_onion<T: secp256k1::Signing>(
1091         secp_ctx: &Secp256k1<T>, path: &Path, session_priv: &SecretKey, total_msat: u64,
1092         recipient_onion: RecipientOnionFields, cur_block_height: u32, payment_hash: &PaymentHash,
1093         keysend_preimage: &Option<PaymentPreimage>, prng_seed: [u8; 32],
1094 ) -> Result<(msgs::OnionPacket, u64, u32), APIError> {
1095         let onion_keys = construct_onion_keys(&secp_ctx, &path, &session_priv).map_err(|_| {
1096                 APIError::InvalidRoute { err: "Pubkey along hop was maliciously selected".to_owned() }
1097         })?;
1098         let (onion_payloads, htlc_msat, htlc_cltv) = build_onion_payloads(
1099                 &path,
1100                 total_msat,
1101                 recipient_onion,
1102                 cur_block_height,
1103                 keysend_preimage,
1104         )?;
1105         let onion_packet = construct_onion_packet(onion_payloads, onion_keys, prng_seed, payment_hash)
1106                 .map_err(|_| APIError::InvalidRoute {
1107                         err: "Route size too large considering onion data".to_owned(),
1108                 })?;
1109         Ok((onion_packet, htlc_msat, htlc_cltv))
1110 }
1111
1112 pub(crate) fn decode_next_untagged_hop<T, R: ReadableArgs<T>, N: NextPacketBytes>(
1113         shared_secret: [u8; 32], hop_data: &[u8], hmac_bytes: [u8; 32], read_args: T,
1114 ) -> Result<(R, Option<([u8; 32], N)>), OnionDecodeErr> {
1115         decode_next_hop(shared_secret, hop_data, hmac_bytes, None, read_args)
1116 }
1117
1118 fn decode_next_hop<T, R: ReadableArgs<T>, N: NextPacketBytes>(
1119         shared_secret: [u8; 32], hop_data: &[u8], hmac_bytes: [u8; 32],
1120         payment_hash: Option<PaymentHash>, read_args: T,
1121 ) -> Result<(R, Option<([u8; 32], N)>), OnionDecodeErr> {
1122         let (rho, mu) = gen_rho_mu_from_shared_secret(&shared_secret);
1123         let mut hmac = HmacEngine::<Sha256>::new(&mu);
1124         hmac.input(hop_data);
1125         if let Some(tag) = payment_hash {
1126                 hmac.input(&tag.0[..]);
1127         }
1128         if !fixed_time_eq(&Hmac::from_engine(hmac).to_byte_array(), &hmac_bytes) {
1129                 return Err(OnionDecodeErr::Malformed {
1130                         err_msg: "HMAC Check failed",
1131                         err_code: 0x8000 | 0x4000 | 5,
1132                 });
1133         }
1134
1135         let mut chacha = ChaCha20::new(&rho, &[0u8; 8]);
1136         let mut chacha_stream = ChaChaReader { chacha: &mut chacha, read: Cursor::new(&hop_data[..]) };
1137         match R::read(&mut chacha_stream, read_args) {
1138                 Err(err) => {
1139                         let error_code = match err {
1140                                 // Unknown realm byte
1141                                 msgs::DecodeError::UnknownVersion => 0x4000 | 1,
1142                                 // invalid_onion_payload
1143                                 msgs::DecodeError::UnknownRequiredFeature
1144                                 | msgs::DecodeError::InvalidValue
1145                                 | msgs::DecodeError::ShortRead => 0x4000 | 22,
1146                                 // Should never happen
1147                                 _ => 0x2000 | 2,
1148                         };
1149                         return Err(OnionDecodeErr::Relay {
1150                                 err_msg: "Unable to decode our hop data",
1151                                 err_code: error_code,
1152                         });
1153                 },
1154                 Ok(msg) => {
1155                         let mut hmac = [0; 32];
1156                         if let Err(_) = chacha_stream.read_exact(&mut hmac[..]) {
1157                                 return Err(OnionDecodeErr::Relay {
1158                                         err_msg: "Unable to decode our hop data",
1159                                         err_code: 0x4000 | 22,
1160                                 });
1161                         }
1162                         if hmac == [0; 32] {
1163                                 #[cfg(test)]
1164                                 {
1165                                         if chacha_stream.read.position() < hop_data.len() as u64 - 64 {
1166                                                 // In tests, make sure that the initial onion packet data is, at least, non-0.
1167                                                 // We could do some fancy randomness test here, but, ehh, whatever.
1168                                                 // This checks for the issue where you can calculate the path length given the
1169                                                 // onion data as all the path entries that the originator sent will be here
1170                                                 // as-is (and were originally 0s).
1171                                                 // Of course reverse path calculation is still pretty easy given naive routing
1172                                                 // algorithms, but this fixes the most-obvious case.
1173                                                 let mut next_bytes = [0; 32];
1174                                                 chacha_stream.read_exact(&mut next_bytes).unwrap();
1175                                                 assert_ne!(next_bytes[..], [0; 32][..]);
1176                                                 chacha_stream.read_exact(&mut next_bytes).unwrap();
1177                                                 assert_ne!(next_bytes[..], [0; 32][..]);
1178                                         }
1179                                 }
1180                                 return Ok((msg, None)); // We are the final destination for this packet
1181                         } else {
1182                                 let mut new_packet_bytes = N::new(hop_data.len());
1183                                 let read_pos = hop_data.len() - chacha_stream.read.position() as usize;
1184                                 chacha_stream.read_exact(&mut new_packet_bytes.as_mut()[..read_pos]).unwrap();
1185                                 #[cfg(debug_assertions)]
1186                                 {
1187                                         // Check two things:
1188                                         // a) that the behavior of our stream here will return Ok(0) even if the TLV
1189                                         //    read above emptied out our buffer and the unwrap() wont needlessly panic
1190                                         // b) that we didn't somehow magically end up with extra data.
1191                                         let mut t = [0; 1];
1192                                         debug_assert!(chacha_stream.read(&mut t).unwrap() == 0);
1193                                 }
1194                                 // Once we've emptied the set of bytes our peer gave us, encrypt 0 bytes until we
1195                                 // fill the onion hop data we'll forward to our next-hop peer.
1196                                 chacha_stream.chacha.process_in_place(&mut new_packet_bytes.as_mut()[read_pos..]);
1197                                 return Ok((msg, Some((hmac, new_packet_bytes)))); // This packet needs forwarding
1198                         }
1199                 },
1200         }
1201 }
1202
1203 #[cfg(test)]
1204 mod tests {
1205         use crate::io;
1206         use crate::ln::features::{ChannelFeatures, NodeFeatures};
1207         use crate::ln::msgs;
1208         use crate::ln::PaymentHash;
1209         use crate::prelude::*;
1210         use crate::routing::router::{Path, Route, RouteHop};
1211         use crate::util::ser::{VecWriter, Writeable, Writer};
1212
1213         use bitcoin::hashes::hex::FromHex;
1214         use bitcoin::secp256k1::Secp256k1;
1215         use bitcoin::secp256k1::{PublicKey, SecretKey};
1216
1217         use super::OnionKeys;
1218
1219         fn get_test_session_key() -> SecretKey {
1220                 let hex = "4141414141414141414141414141414141414141414141414141414141414141";
1221                 SecretKey::from_slice(&<Vec<u8>>::from_hex(hex).unwrap()[..]).unwrap()
1222         }
1223
1224         fn build_test_onion_keys() -> Vec<OnionKeys> {
1225                 // Keys from BOLT 4, used in both test vector tests
1226                 let secp_ctx = Secp256k1::new();
1227
1228                 let route = Route {
1229                         paths: vec![Path { hops: vec![
1230                                         RouteHop {
1231                                                 pubkey: PublicKey::from_slice(&<Vec<u8>>::from_hex("02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619").unwrap()[..]).unwrap(),
1232                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
1233                                                 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.
1234                                         },
1235                                         RouteHop {
1236                                                 pubkey: PublicKey::from_slice(&<Vec<u8>>::from_hex("0324653eac434488002cc06bbfb7f10fe18991e35f9fe4302dbea6d2353dc0ab1c").unwrap()[..]).unwrap(),
1237                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
1238                                                 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.
1239                                         },
1240                                         RouteHop {
1241                                                 pubkey: PublicKey::from_slice(&<Vec<u8>>::from_hex("027f31ebc5462c1fdce1b737ecff52d37d75dea43ce11c74d25aa297165faa2007").unwrap()[..]).unwrap(),
1242                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
1243                                                 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.
1244                                         },
1245                                         RouteHop {
1246                                                 pubkey: PublicKey::from_slice(&<Vec<u8>>::from_hex("032c0b7cf95324a07d05398b240174dc0c2be444d96b159aa6c7f7b1e668680991").unwrap()[..]).unwrap(),
1247                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
1248                                                 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.
1249                                         },
1250                                         RouteHop {
1251                                                 pubkey: PublicKey::from_slice(&<Vec<u8>>::from_hex("02edabbd16b41c8371b92ef2f04c1185b4f03b6dcd52ba9b78d9d7c89c8f221145").unwrap()[..]).unwrap(),
1252                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
1253                                                 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.
1254                                         },
1255                         ], blinded_tail: None }],
1256                         route_params: None,
1257                 };
1258
1259                 let onion_keys =
1260                         super::construct_onion_keys(&secp_ctx, &route.paths[0], &get_test_session_key())
1261                                 .unwrap();
1262                 assert_eq!(onion_keys.len(), route.paths[0].hops.len());
1263                 onion_keys
1264         }
1265
1266         #[test]
1267         fn onion_vectors() {
1268                 let onion_keys = build_test_onion_keys();
1269
1270                 // Test generation of ephemeral keys and secrets. These values used to be part of the BOLT4
1271                 // test vectors, but have since been removed. We keep them as they provide test coverage.
1272                 let hex = "53eb63ea8a3fec3b3cd433b85cd62a4b145e1dda09391b348c4e1cd36a03ea66";
1273                 assert_eq!(
1274                         onion_keys[0].shared_secret.secret_bytes(),
1275                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1276                 );
1277
1278                 let hex = "2ec2e5da605776054187180343287683aa6a51b4b1c04d6dd49c45d8cffb3c36";
1279                 assert_eq!(onion_keys[0].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
1280
1281                 let hex = "02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619";
1282                 assert_eq!(
1283                         onion_keys[0].ephemeral_pubkey.serialize()[..],
1284                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1285                 );
1286
1287                 let hex = "ce496ec94def95aadd4bec15cdb41a740c9f2b62347c4917325fcc6fb0453986";
1288                 assert_eq!(onion_keys[0].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1289
1290                 let hex = "b57061dc6d0a2b9f261ac410c8b26d64ac5506cbba30267a649c28c179400eba";
1291                 assert_eq!(onion_keys[0].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1292
1293                 let hex = "a6519e98832a0b179f62123b3567c106db99ee37bef036e783263602f3488fae";
1294                 assert_eq!(
1295                         onion_keys[1].shared_secret.secret_bytes(),
1296                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1297                 );
1298
1299                 let hex = "bf66c28bc22e598cfd574a1931a2bafbca09163df2261e6d0056b2610dab938f";
1300                 assert_eq!(onion_keys[1].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
1301
1302                 let hex = "028f9438bfbf7feac2e108d677e3a82da596be706cc1cf342b75c7b7e22bf4e6e2";
1303                 assert_eq!(
1304                         onion_keys[1].ephemeral_pubkey.serialize()[..],
1305                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1306                 );
1307
1308                 let hex = "450ffcabc6449094918ebe13d4f03e433d20a3d28a768203337bc40b6e4b2c59";
1309                 assert_eq!(onion_keys[1].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1310
1311                 let hex = "05ed2b4a3fb023c2ff5dd6ed4b9b6ea7383f5cfe9d59c11d121ec2c81ca2eea9";
1312                 assert_eq!(onion_keys[1].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1313
1314                 let hex = "3a6b412548762f0dbccce5c7ae7bb8147d1caf9b5471c34120b30bc9c04891cc";
1315                 assert_eq!(
1316                         onion_keys[2].shared_secret.secret_bytes(),
1317                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1318                 );
1319
1320                 let hex = "a1f2dadd184eb1627049673f18c6325814384facdee5bfd935d9cb031a1698a5";
1321                 assert_eq!(onion_keys[2].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
1322
1323                 let hex = "03bfd8225241ea71cd0843db7709f4c222f62ff2d4516fd38b39914ab6b83e0da0";
1324                 assert_eq!(
1325                         onion_keys[2].ephemeral_pubkey.serialize()[..],
1326                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1327                 );
1328
1329                 let hex = "11bf5c4f960239cb37833936aa3d02cea82c0f39fd35f566109c41f9eac8deea";
1330                 assert_eq!(onion_keys[2].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1331
1332                 let hex = "caafe2820fa00eb2eeb78695ae452eba38f5a53ed6d53518c5c6edf76f3f5b78";
1333                 assert_eq!(onion_keys[2].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1334
1335                 let hex = "21e13c2d7cfe7e18836df50872466117a295783ab8aab0e7ecc8c725503ad02d";
1336                 assert_eq!(
1337                         onion_keys[3].shared_secret.secret_bytes(),
1338                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1339                 );
1340
1341                 let hex = "7cfe0b699f35525029ae0fa437c69d0f20f7ed4e3916133f9cacbb13c82ff262";
1342                 assert_eq!(onion_keys[3].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
1343
1344                 let hex = "031dde6926381289671300239ea8e57ffaf9bebd05b9a5b95beaf07af05cd43595";
1345                 assert_eq!(
1346                         onion_keys[3].ephemeral_pubkey.serialize()[..],
1347                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1348                 );
1349
1350                 let hex = "cbe784ab745c13ff5cffc2fbe3e84424aa0fd669b8ead4ee562901a4a4e89e9e";
1351                 assert_eq!(onion_keys[3].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1352
1353                 let hex = "5052aa1b3d9f0655a0932e50d42f0c9ba0705142c25d225515c45f47c0036ee9";
1354                 assert_eq!(onion_keys[3].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1355
1356                 let hex = "b5756b9b542727dbafc6765a49488b023a725d631af688fc031217e90770c328";
1357                 assert_eq!(
1358                         onion_keys[4].shared_secret.secret_bytes(),
1359                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1360                 );
1361
1362                 let hex = "c96e00dddaf57e7edcd4fb5954be5b65b09f17cb6d20651b4e90315be5779205";
1363                 assert_eq!(onion_keys[4].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
1364
1365                 let hex = "03a214ebd875aab6ddfd77f22c5e7311d7f77f17a169e599f157bbcdae8bf071f4";
1366                 assert_eq!(
1367                         onion_keys[4].ephemeral_pubkey.serialize()[..],
1368                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1369                 );
1370
1371                 let hex = "034e18b8cc718e8af6339106e706c52d8df89e2b1f7e9142d996acf88df8799b";
1372                 assert_eq!(onion_keys[4].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1373
1374                 let hex = "8e45e5c61c2b24cb6382444db6698727afb063adecd72aada233d4bf273d975a";
1375                 assert_eq!(onion_keys[4].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1376
1377                 // Packet creation test vectors from BOLT 4 (see
1378                 // https://github.com/lightning/bolts/blob/16973e2b857e853308cafd59e42fa830d75b1642/bolt04/onion-test.json).
1379                 // Note that we represent the test vector payloads 2 and 5 through RawOnionHopData::data
1380                 // with raw hex instead of our in-memory enums, as the payloads contains custom types, and
1381                 // we have no way of representing that with our enums.
1382                 let payloads = vec!(
1383                         RawOnionHopData::new(msgs::OutboundOnionPayload::Forward {
1384                                 short_channel_id: 1,
1385                                 amt_to_forward: 15000,
1386                                 outgoing_cltv_value: 1500,
1387                         }),
1388                         /*
1389                         The second payload is represented by raw hex as it contains custom type data. Content:
1390                         1. length "52" (payload_length 82).
1391
1392                         The first part of the payload has the `NonFinalNode` format, with content as follows:
1393                         2. amt_to_forward "020236b0"
1394                            02 (type amt_to_forward) 02 (length 2) 36b0 (value 14000)
1395                         3. outgoing_cltv_value "04020578"
1396                            04 (type outgoing_cltv_value) 02 (length 2) 0578 (value 1400)
1397                         4. short_channel_id "06080000000000000002"
1398                            06 (type short_channel_id) 08 (length 8) 0000000000000002 (value 2)
1399
1400                         The rest of the payload is custom type data:
1401                         5. custom_record "fd02013c0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f"
1402                         */
1403                         RawOnionHopData {
1404                                 data: <Vec<u8>>::from_hex("52020236b00402057806080000000000000002fd02013c0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f").unwrap(),
1405                         },
1406                         RawOnionHopData::new(msgs::OutboundOnionPayload::Forward {
1407                                 short_channel_id: 3,
1408                                 amt_to_forward: 12500,
1409                                 outgoing_cltv_value: 1250,
1410                         }),
1411                         RawOnionHopData::new(msgs::OutboundOnionPayload::Forward {
1412                                 short_channel_id: 4,
1413                                 amt_to_forward: 10000,
1414                                 outgoing_cltv_value: 1000,
1415                         }),
1416                         /*
1417                         The fifth payload is represented by raw hex as it contains custom type data. Content:
1418                         1. length "fd0110" (payload_length 272).
1419
1420                         The first part of the payload has the `FinalNode` format, with content as follows:
1421                         1. amt_to_forward "02022710"
1422                            02 (type amt_to_forward) 02 (length 2) 2710 (value 10000)
1423                         2. outgoing_cltv_value "040203e8"
1424                            04 (type outgoing_cltv_value) 02 (length 2) 03e8 (value 1000)
1425                         3. payment_data "082224a33562c54507a9334e79f0dc4f17d407e6d7c61f0e2f3d0d38599502f617042710"
1426                            08 (type short_channel_id) 22 (length 34) 24a33562c54507a9334e79f0dc4f17d407e6d7c61f0e2f3d0d38599502f61704 (payment_secret) 2710 (total_msat value 10000)
1427
1428                         The rest of the payload is custom type data:
1429                         4. custom_record "fd012de02a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a"
1430                         */
1431                         RawOnionHopData {
1432                                 data: <Vec<u8>>::from_hex("fd011002022710040203e8082224a33562c54507a9334e79f0dc4f17d407e6d7c61f0e2f3d0d38599502f617042710fd012de02a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a").unwrap(),
1433                         },
1434                 );
1435
1436                 // Verify that the serialized OnionHopDataFormat::NonFinalNode tlv payloads matches the test vectors
1437                 let mut w = VecWriter(Vec::new());
1438                 payloads[0].write(&mut w).unwrap();
1439                 let hop_1_serialized_payload = w.0;
1440                 let hex = "1202023a98040205dc06080000000000000001";
1441                 let expected_serialized_hop_1_payload = &<Vec<u8>>::from_hex(hex).unwrap()[..];
1442                 assert_eq!(hop_1_serialized_payload, expected_serialized_hop_1_payload);
1443
1444                 w = VecWriter(Vec::new());
1445                 payloads[2].write(&mut w).unwrap();
1446                 let hop_3_serialized_payload = w.0;
1447                 let hex = "12020230d4040204e206080000000000000003";
1448                 let expected_serialized_hop_3_payload = &<Vec<u8>>::from_hex(hex).unwrap()[..];
1449                 assert_eq!(hop_3_serialized_payload, expected_serialized_hop_3_payload);
1450
1451                 w = VecWriter(Vec::new());
1452                 payloads[3].write(&mut w).unwrap();
1453                 let hop_4_serialized_payload = w.0;
1454                 let hex = "1202022710040203e806080000000000000004";
1455                 let expected_serialized_hop_4_payload = &<Vec<u8>>::from_hex(hex).unwrap()[..];
1456                 assert_eq!(hop_4_serialized_payload, expected_serialized_hop_4_payload);
1457
1458                 let pad_keytype_seed =
1459                         super::gen_pad_from_shared_secret(&get_test_session_key().secret_bytes());
1460
1461                 let packet: msgs::OnionPacket = super::construct_onion_packet_with_writable_hopdata::<_>(
1462                         payloads,
1463                         onion_keys,
1464                         pad_keytype_seed,
1465                         &PaymentHash([0x42; 32]),
1466                 )
1467                 .unwrap();
1468
1469                 let hex = 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
1470                 assert_eq!(packet.encode(), <Vec<u8>>::from_hex(hex).unwrap());
1471         }
1472
1473         #[test]
1474         fn test_failure_packet_onion() {
1475                 // Returning Errors test vectors from BOLT 4
1476
1477                 let onion_keys = build_test_onion_keys();
1478                 let onion_error =
1479                         super::build_failure_packet(onion_keys[4].shared_secret.as_ref(), 0x2002, &[0; 0]);
1480                 let hex = "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";
1481                 assert_eq!(onion_error.encode(), <Vec<u8>>::from_hex(hex).unwrap());
1482
1483                 let onion_packet_1 = super::encrypt_failure_packet(
1484                         onion_keys[4].shared_secret.as_ref(),
1485                         &onion_error.encode()[..],
1486                 );
1487                 let hex = "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";
1488                 assert_eq!(onion_packet_1.data, <Vec<u8>>::from_hex(hex).unwrap());
1489
1490                 let onion_packet_2 = super::encrypt_failure_packet(
1491                         onion_keys[3].shared_secret.as_ref(),
1492                         &onion_packet_1.data[..],
1493                 );
1494                 let hex = "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";
1495                 assert_eq!(onion_packet_2.data, <Vec<u8>>::from_hex(hex).unwrap());
1496
1497                 let onion_packet_3 = super::encrypt_failure_packet(
1498                         onion_keys[2].shared_secret.as_ref(),
1499                         &onion_packet_2.data[..],
1500                 );
1501                 let hex = "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";
1502                 assert_eq!(onion_packet_3.data, <Vec<u8>>::from_hex(hex).unwrap());
1503
1504                 let onion_packet_4 = super::encrypt_failure_packet(
1505                         onion_keys[1].shared_secret.as_ref(),
1506                         &onion_packet_3.data[..],
1507                 );
1508                 let hex = "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";
1509                 assert_eq!(onion_packet_4.data, <Vec<u8>>::from_hex(hex).unwrap());
1510
1511                 let onion_packet_5 = super::encrypt_failure_packet(
1512                         onion_keys[0].shared_secret.as_ref(),
1513                         &onion_packet_4.data[..],
1514                 );
1515                 let hex = "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";
1516                 assert_eq!(onion_packet_5.data, <Vec<u8>>::from_hex(hex).unwrap());
1517         }
1518
1519         struct RawOnionHopData {
1520                 data: Vec<u8>,
1521         }
1522         impl RawOnionHopData {
1523                 fn new(orig: msgs::OutboundOnionPayload) -> Self {
1524                         Self { data: orig.encode() }
1525                 }
1526         }
1527         impl Writeable for RawOnionHopData {
1528                 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
1529                         writer.write_all(&self.data[..])
1530                 }
1531         }
1532 }