git.bitcoin.ninja 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::types::{PaymentHash, PaymentPreimage};
  15 use crate::ln::wire::Encode;
  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 core::ops::Deref;
  34
  35 #[allow(unused_imports)]
  36 use crate::prelude::*;
  37
  38 pub(crate) struct OnionKeys {
  39         #[cfg(test)]
  40         pub(crate) shared_secret: SharedSecret,
  41         #[cfg(test)]
  42         pub(crate) blinding_factor: [u8; 32],
  43         pub(crate) ephemeral_pubkey: PublicKey,
  44         pub(crate) rho: [u8; 32],
  45         pub(crate) mu: [u8; 32],
  46 }
  47
  48 #[inline]
  49 pub(crate) fn gen_rho_from_shared_secret(shared_secret: &[u8]) -> [u8; 32] {
  50         assert_eq!(shared_secret.len(), 32);
  51         let mut hmac = HmacEngine::<Sha256>::new(&[0x72, 0x68, 0x6f]); // rho
  52         hmac.input(&shared_secret);
  53         Hmac::from_engine(hmac).to_byte_array()
  54 }
  55
  56 #[inline]
  57 pub(crate) fn gen_rho_mu_from_shared_secret(shared_secret: &[u8]) -> ([u8; 32], [u8; 32]) {
  58         assert_eq!(shared_secret.len(), 32);
  59         let mut engine_rho = HmacEngine::<Sha256>::new(b"rho");
  60         engine_rho.input(&shared_secret);
  61         let hmac_rho = Hmac::from_engine(engine_rho).to_byte_array();
  62
  63         let mut engine_mu = HmacEngine::<Sha256>::new(b"mu");
  64         engine_mu.input(&shared_secret);
  65         let hmac_mu = Hmac::from_engine(engine_mu).to_byte_array();
  66
  67         (hmac_rho, hmac_mu)
  68 }
  69
  70 #[inline]
  71 pub(super) fn gen_um_from_shared_secret(shared_secret: &[u8]) -> [u8; 32] {
  72         assert_eq!(shared_secret.len(), 32);
  73         let mut hmac = HmacEngine::<Sha256>::new(&[0x75, 0x6d]); // um
  74         hmac.input(&shared_secret);
  75         Hmac::from_engine(hmac).to_byte_array()
  76 }
  77
  78 #[inline]
  79 pub(super) fn gen_ammag_from_shared_secret(shared_secret: &[u8]) -> [u8; 32] {
  80         assert_eq!(shared_secret.len(), 32);
  81         let mut hmac = HmacEngine::<Sha256>::new(&[0x61, 0x6d, 0x6d, 0x61, 0x67]); // ammag
  82         hmac.input(&shared_secret);
  83         Hmac::from_engine(hmac).to_byte_array()
  84 }
  85
  86 #[cfg(test)]
  87 #[inline]
  88 pub(super) fn gen_pad_from_shared_secret(shared_secret: &[u8]) -> [u8; 32] {
  89         assert_eq!(shared_secret.len(), 32);
  90         let mut hmac = HmacEngine::<Sha256>::new(&[0x70, 0x61, 0x64]); // pad
  91         hmac.input(&shared_secret);
  92         Hmac::from_engine(hmac).to_byte_array()
  93 }
  94
  95 /// Calculates a pubkey for the next hop, such as the next hop's packet pubkey or blinding point.
  96 pub(crate) fn next_hop_pubkey<T: secp256k1::Verification>(
  97         secp_ctx: &Secp256k1<T>, curr_pubkey: PublicKey, shared_secret: &[u8],
  98 ) -> Result<PublicKey, secp256k1::Error> {
  99         let blinding_factor = {
 100                 let mut sha = Sha256::engine();
 101                 sha.input(&curr_pubkey.serialize()[..]);
 102                 sha.input(shared_secret);
 103                 Sha256::from_engine(sha).to_byte_array()
 104         };
 105
 106         curr_pubkey.mul_tweak(secp_ctx, &Scalar::from_be_bytes(blinding_factor).unwrap())
 107 }
 108
 109 // can only fail if an intermediary hop has an invalid public key or session_priv is invalid
 110 #[inline]
 111 pub(super) fn construct_onion_keys_callback<T, FType>(
 112         secp_ctx: &Secp256k1<T>, path: &Path, session_priv: &SecretKey, mut callback: FType,
 113 ) -> Result<(), secp256k1::Error>
 114 where
 115         T: secp256k1::Signing,
 116         FType: FnMut(SharedSecret, [u8; 32], PublicKey, Option<&RouteHop>, usize),
 117 {
 118         let mut blinded_priv = session_priv.clone();
 119         let mut blinded_pub = PublicKey::from_secret_key(secp_ctx, &blinded_priv);
 120
 121         let unblinded_hops_iter = path.hops.iter().map(|h| (&h.pubkey, Some(h)));
 122         let blinded_pks_iter = path
 123                 .blinded_tail
 124                 .as_ref()
 125                 .map(|t| t.hops.iter())
 126                 .unwrap_or([].iter())
 127                 .skip(1) // Skip the intro node because it's included in the unblinded hops
 128                 .map(|h| (&h.blinded_node_id, None));
 129         for (idx, (pubkey, route_hop_opt)) in unblinded_hops_iter.chain(blinded_pks_iter).enumerate() {
 130                 let shared_secret = SharedSecret::new(pubkey, &blinded_priv);
 131
 132                 let mut sha = Sha256::engine();
 133                 sha.input(&blinded_pub.serialize()[..]);
 134                 sha.input(shared_secret.as_ref());
 135                 let blinding_factor = Sha256::from_engine(sha).to_byte_array();
 136
 137                 let ephemeral_pubkey = blinded_pub;
 138
 139                 blinded_priv = blinded_priv.mul_tweak(&Scalar::from_be_bytes(blinding_factor).unwrap())?;
 140                 blinded_pub = PublicKey::from_secret_key(secp_ctx, &blinded_priv);
 141
 142                 callback(shared_secret, blinding_factor, ephemeral_pubkey, route_hop_opt, idx);
 143         }
 144
 145         Ok(())
 146 }
 147
 148 // can only fail if an intermediary hop has an invalid public key or session_priv is invalid
 149 pub(super) fn construct_onion_keys<T: secp256k1::Signing>(
 150         secp_ctx: &Secp256k1<T>, path: &Path, session_priv: &SecretKey,
 151 ) -> Result<Vec<OnionKeys>, secp256k1::Error> {
 152         let mut res = Vec::with_capacity(path.hops.len());
 153
 154         construct_onion_keys_callback(
 155                 secp_ctx,
 156                 &path,
 157                 session_priv,
 158                 |shared_secret, _blinding_factor, ephemeral_pubkey, _, _| {
 159                         let (rho, mu) = gen_rho_mu_from_shared_secret(shared_secret.as_ref());
 160
 161                         res.push(OnionKeys {
 162                                 #[cfg(test)]
 163                                 shared_secret,
 164                                 #[cfg(test)]
 165                                 blinding_factor: _blinding_factor,
 166                                 ephemeral_pubkey,
 167                                 rho,
 168                                 mu,
 169                         });
 170                 },
 171         )?;
 172
 173         Ok(res)
 174 }
 175
 176 /// returns the hop data, as well as the first-hop value_msat and CLTV value we should send.
 177 pub(super) fn build_onion_payloads(
 178         path: &Path, total_msat: u64, mut recipient_onion: RecipientOnionFields,
 179         starting_htlc_offset: u32, keysend_preimage: &Option<PaymentPreimage>,
 180 ) -> Result<(Vec<msgs::OutboundOnionPayload>, u64, u32), APIError> {
 181         let mut cur_value_msat = 0u64;
 182         let mut cur_cltv = starting_htlc_offset;
 183         let mut last_short_channel_id = 0;
 184         let mut res: Vec<msgs::OutboundOnionPayload> = Vec::with_capacity(
 185                 path.hops.len() + path.blinded_tail.as_ref().map_or(0, |t| t.hops.len()),
 186         );
 187
 188         for (idx, hop) in path.hops.iter().rev().enumerate() {
 189                 // First hop gets special values so that it can check, on receipt, that everything is
 190                 // exactly as it should be (and the next hop isn't trying to probe to find out if we're
 191                 // the intended recipient).
 192                 let value_msat = if cur_value_msat == 0 { hop.fee_msat } else { cur_value_msat };
 193                 let cltv = if cur_cltv == starting_htlc_offset {
 194                         hop.cltv_expiry_delta + starting_htlc_offset
 195                 } else {
 196                         cur_cltv
 197                 };
 198                 if idx == 0 {
 199                         if let Some(BlindedTail {
 200                                 blinding_point,
 201                                 hops,
 202                                 final_value_msat,
 203                                 excess_final_cltv_expiry_delta,
 204                                 ..
 205                         }) = &path.blinded_tail
 206                         {
 207                                 let mut blinding_point = Some(*blinding_point);
 208                                 for (i, blinded_hop) in hops.iter().enumerate() {
 209                                         if i == hops.len() - 1 {
 210                                                 cur_value_msat += final_value_msat;
 211                                                 res.push(msgs::OutboundOnionPayload::BlindedReceive {
 212                                                         sender_intended_htlc_amt_msat: *final_value_msat,
 213                                                         total_msat,
 214                                                         cltv_expiry_height: cur_cltv + excess_final_cltv_expiry_delta,
 215                                                         encrypted_tlvs: blinded_hop.encrypted_payload.clone(),
 216                                                         intro_node_blinding_point: blinding_point.take(),
 217                                                         keysend_preimage: *keysend_preimage,
 218                                                         custom_tlvs: recipient_onion.custom_tlvs.clone(),
 219                                                 });
 220                                         } else {
 221                                                 res.push(msgs::OutboundOnionPayload::BlindedForward {
 222                                                         encrypted_tlvs: blinded_hop.encrypted_payload.clone(),
 223                                                         intro_node_blinding_point: blinding_point.take(),
 224                                                 });
 225                                         }
 226                                 }
 227                         } else {
 228                                 res.push(msgs::OutboundOnionPayload::Receive {
 229                                         payment_data: if let Some(secret) = recipient_onion.payment_secret.take() {
 230                                                 Some(msgs::FinalOnionHopData { payment_secret: secret, total_msat })
 231                                         } else {
 232                                                 None
 233                                         },
 234                                         payment_metadata: recipient_onion.payment_metadata.take(),
 235                                         keysend_preimage: *keysend_preimage,
 236                                         custom_tlvs: recipient_onion.custom_tlvs.clone(),
 237                                         sender_intended_htlc_amt_msat: value_msat,
 238                                         cltv_expiry_height: cltv,
 239                                 });
 240                         }
 241                 } else {
 242                         let payload = msgs::OutboundOnionPayload::Forward {
 243                                 short_channel_id: last_short_channel_id,
 244                                 amt_to_forward: value_msat,
 245                                 outgoing_cltv_value: cltv,
 246                         };
 247                         res.insert(0, payload);
 248                 }
 249                 cur_value_msat += hop.fee_msat;
 250                 if cur_value_msat >= 21000000 * 100000000 * 1000 {
 251                         return Err(APIError::InvalidRoute { err: "Channel fees overflowed?".to_owned() });
 252                 }
 253                 cur_cltv += hop.cltv_expiry_delta as u32;
 254                 if cur_cltv >= 500000000 {
 255                         return Err(APIError::InvalidRoute { err: "Channel CLTV overflowed?".to_owned() });
 256                 }
 257                 last_short_channel_id = hop.short_channel_id;
 258         }
 259         Ok((res, cur_value_msat, cur_cltv))
 260 }
 261
 262 /// Length of the onion data packet. Before TLV-based onions this was 20 65-byte hops, though now
 263 /// the hops can be of variable length.
 264 pub(crate) const ONION_DATA_LEN: usize = 20 * 65;
 265
 266 pub(super) const INVALID_ONION_BLINDING: u16 = 0x8000 | 0x4000 | 24;
 267
 268 #[inline]
 269 fn shift_slice_right(arr: &mut [u8], amt: usize) {
 270         for i in (amt..arr.len()).rev() {
 271                 arr[i] = arr[i - amt];
 272         }
 273         for i in 0..amt {
 274                 arr[i] = 0;
 275         }
 276 }
 277
 278 pub(super) fn construct_onion_packet(
 279         payloads: Vec<msgs::OutboundOnionPayload>, onion_keys: Vec<OnionKeys>, prng_seed: [u8; 32],
 280         associated_data: &PaymentHash,
 281 ) -> Result<msgs::OnionPacket, ()> {
 282         let mut packet_data = [0; ONION_DATA_LEN];
 283
 284         let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
 285         chacha.process(&[0; ONION_DATA_LEN], &mut packet_data);
 286
 287         let packet = FixedSizeOnionPacket(packet_data);
 288         construct_onion_packet_with_init_noise::<_, _>(
 289                 payloads,
 290                 onion_keys,
 291                 packet,
 292                 Some(associated_data),
 293         )
 294 }
 295
 296 #[allow(unused)]
 297 pub(super) fn construct_trampoline_onion_packet(
 298         payloads: Vec<msgs::OutboundTrampolinePayload>, onion_keys: Vec<OnionKeys>,
 299         prng_seed: [u8; 32], associated_data: &PaymentHash, length: u16,
 300 ) -> Result<msgs::TrampolineOnionPacket, ()> {
 301         let mut packet_data = vec![0u8; length as usize];
 302
 303         let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
 304         chacha.process(&vec![0u8; length as usize], &mut packet_data);
 305
 306         construct_onion_packet_with_init_noise::<_, _>(
 307                 payloads,
 308                 onion_keys,
 309                 packet_data,
 310                 Some(associated_data),
 311         )
 312 }
 313
 314 #[cfg(test)]
 315 /// Used in testing to write bogus `BogusOnionHopData` as well as `RawOnionHopData`, which is
 316 /// otherwise not representable in `msgs::OnionHopData`.
 317 pub(super) fn construct_onion_packet_with_writable_hopdata<HD: Writeable>(
 318         payloads: Vec<HD>, onion_keys: Vec<OnionKeys>, prng_seed: [u8; 32],
 319         associated_data: &PaymentHash,
 320 ) -> Result<msgs::OnionPacket, ()> {
 321         let mut packet_data = [0; ONION_DATA_LEN];
 322
 323         let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
 324         chacha.process(&[0; ONION_DATA_LEN], &mut packet_data);
 325
 326         let packet = FixedSizeOnionPacket(packet_data);
 327         construct_onion_packet_with_init_noise::<_, _>(
 328                 payloads,
 329                 onion_keys,
 330                 packet,
 331                 Some(associated_data),
 332         )
 333 }
 334
 335 /// Since onion message packets and onion payment packets have different lengths but are otherwise
 336 /// identical, we use this trait to allow `construct_onion_packet_with_init_noise` to return either
 337 /// type.
 338 pub(crate) trait Packet {
 339         type Data: AsMut<[u8]>;
 340         fn new(pubkey: PublicKey, hop_data: Self::Data, hmac: [u8; 32]) -> Self;
 341 }
 342
 343 // Needed for rustc versions older than 1.47 to avoid E0277: "arrays only have std trait
 344 // implementations for lengths 0..=32".
 345 pub(crate) struct FixedSizeOnionPacket(pub(crate) [u8; ONION_DATA_LEN]);
 346
 347 impl AsMut<[u8]> for FixedSizeOnionPacket {
 348         fn as_mut(&mut self) -> &mut [u8] {
 349                 &mut self.0
 350         }
 351 }
 352
 353 pub(crate) fn payloads_serialized_length<HD: Writeable>(payloads: &Vec<HD>) -> usize {
 354         payloads.iter().map(|p| p.serialized_length() + 32 /* HMAC */).sum()
 355 }
 356
 357 pub(crate) fn construct_onion_message_packet<HD: Writeable, P: Packet<Data = Vec<u8>>>(
 358         payloads: Vec<HD>, onion_keys: Vec<OnionKeys>, prng_seed: [u8; 32], packet_data_len: usize,
 359 ) -> Result<P, ()> {
 360         let mut packet_data = vec![0; packet_data_len];
 361
 362         let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
 363         chacha.process_in_place(&mut packet_data);
 364
 365         construct_onion_packet_with_init_noise::<_, _>(payloads, onion_keys, packet_data, None)
 366 }
 367
 368 fn construct_onion_packet_with_init_noise<HD: Writeable, P: Packet>(
 369         mut payloads: Vec<HD>, onion_keys: Vec<OnionKeys>, mut packet_data: P::Data,
 370         associated_data: Option<&PaymentHash>,
 371 ) -> Result<P, ()> {
 372         let filler = {
 373                 let packet_data = packet_data.as_mut();
 374                 const ONION_HOP_DATA_LEN: usize = 65; // We may decrease this eventually after TLV is common
 375                 let mut res = Vec::with_capacity(ONION_HOP_DATA_LEN * (payloads.len() - 1));
 376
 377                 let mut pos = 0;
 378                 for (i, (payload, keys)) in payloads.iter().zip(onion_keys.iter()).enumerate() {
 379                         let mut chacha = ChaCha20::new(&keys.rho, &[0u8; 8]);
 380                         // TODO: Batch this.
 381                         for _ in 0..(packet_data.len() - pos) {
 382                                 let mut dummy = [0; 1];
 383                                 chacha.process_in_place(&mut dummy); // We don't have a seek function :(
 384                         }
 385
 386                         let mut payload_len = LengthCalculatingWriter(0);
 387                         payload.write(&mut payload_len).expect("Failed to calculate length");
 388                         pos += payload_len.0 + 32;
 389                         if pos > packet_data.len() {
 390                                 return Err(());
 391                         }
 392
 393                         if i == payloads.len() - 1 {
 394                                 break;
 395                         }
 396
 397                         res.resize(pos, 0u8);
 398                         chacha.process_in_place(&mut res);
 399                 }
 400                 res
 401         };
 402
 403         let mut hmac_res = [0; 32];
 404         for (i, (payload, keys)) in payloads.iter_mut().zip(onion_keys.iter()).rev().enumerate() {
 405                 let mut payload_len = LengthCalculatingWriter(0);
 406                 payload.write(&mut payload_len).expect("Failed to calculate length");
 407
 408                 let packet_data = packet_data.as_mut();
 409                 shift_slice_right(packet_data, payload_len.0 + 32);
 410                 packet_data[0..payload_len.0].copy_from_slice(&payload.encode()[..]);
 411                 packet_data[payload_len.0..(payload_len.0 + 32)].copy_from_slice(&hmac_res);
 412
 413                 let mut chacha = ChaCha20::new(&keys.rho, &[0u8; 8]);
 414                 chacha.process_in_place(packet_data);
 415
 416                 if i == 0 {
 417                         let stop_index = packet_data.len();
 418                         let start_index = stop_index.checked_sub(filler.len()).ok_or(())?;
 419                         packet_data[start_index..stop_index].copy_from_slice(&filler[..]);
 420                 }
 421
 422                 let mut hmac = HmacEngine::<Sha256>::new(&keys.mu);
 423                 hmac.input(packet_data);
 424                 if let Some(associated_data) = associated_data {
 425                         hmac.input(&associated_data.0[..]);
 426                 }
 427                 hmac_res = Hmac::from_engine(hmac).to_byte_array();
 428         }
 429
 430         Ok(P::new(onion_keys.first().unwrap().ephemeral_pubkey, packet_data, hmac_res))
 431 }
 432
 433 /// Encrypts a failure packet. raw_packet can either be a
 434 /// msgs::DecodedOnionErrorPacket.encode() result or a msgs::OnionErrorPacket.data element.
 435 pub(super) fn encrypt_failure_packet(
 436         shared_secret: &[u8], raw_packet: &[u8],
 437 ) -> msgs::OnionErrorPacket {
 438         let ammag = gen_ammag_from_shared_secret(&shared_secret);
 439
 440         let mut packet_crypted = Vec::with_capacity(raw_packet.len());
 441         packet_crypted.resize(raw_packet.len(), 0);
 442         let mut chacha = ChaCha20::new(&ammag, &[0u8; 8]);
 443         chacha.process(&raw_packet, &mut packet_crypted[..]);
 444         msgs::OnionErrorPacket { data: packet_crypted }
 445 }
 446
 447 pub(super) fn build_failure_packet(
 448         shared_secret: &[u8], failure_type: u16, failure_data: &[u8],
 449 ) -> msgs::DecodedOnionErrorPacket {
 450         assert_eq!(shared_secret.len(), 32);
 451         assert!(failure_data.len() <= 256 - 2);
 452
 453         let um = gen_um_from_shared_secret(&shared_secret);
 454
 455         let failuremsg = {
 456                 let mut res = Vec::with_capacity(2 + failure_data.len());
 457                 res.push(((failure_type >> 8) & 0xff) as u8);
 458                 res.push(((failure_type >> 0) & 0xff) as u8);
 459                 res.extend_from_slice(&failure_data[..]);
 460                 res
 461         };
 462         let pad = {
 463                 let mut res = Vec::with_capacity(256 - 2 - failure_data.len());
 464                 res.resize(256 - 2 - failure_data.len(), 0);
 465                 res
 466         };
 467         let mut packet = msgs::DecodedOnionErrorPacket { hmac: [0; 32], failuremsg, pad };
 468
 469         let mut hmac = HmacEngine::<Sha256>::new(&um);
 470         hmac.input(&packet.encode()[32..]);
 471         packet.hmac = Hmac::from_engine(hmac).to_byte_array();
 472
 473         packet
 474 }
 475
 476 #[cfg(test)]
 477 pub(super) fn build_first_hop_failure_packet(
 478         shared_secret: &[u8], failure_type: u16, failure_data: &[u8],
 479 ) -> msgs::OnionErrorPacket {
 480         let failure_packet = build_failure_packet(shared_secret, failure_type, failure_data);
 481         encrypt_failure_packet(shared_secret, &failure_packet.encode()[..])
 482 }
 483
 484 pub(crate) struct DecodedOnionFailure {
 485         pub(crate) network_update: Option<NetworkUpdate>,
 486         pub(crate) short_channel_id: Option<u64>,
 487         pub(crate) payment_failed_permanently: bool,
 488         pub(crate) failed_within_blinded_path: bool,
 489         #[cfg(test)]
 490         pub(crate) onion_error_code: Option<u16>,
 491         #[cfg(test)]
 492         pub(crate) onion_error_data: Option<Vec<u8>>,
 493 }
 494
 495 /// Note that we always decrypt `packet` in-place here even if the deserialization into
 496 /// [`msgs::DecodedOnionErrorPacket`] ultimately fails.
 497 fn decrypt_onion_error_packet(
 498         packet: &mut Vec<u8>, shared_secret: SharedSecret,
 499 ) -> Result<msgs::DecodedOnionErrorPacket, msgs::DecodeError> {
 500         let ammag = gen_ammag_from_shared_secret(shared_secret.as_ref());
 501         let mut chacha = ChaCha20::new(&ammag, &[0u8; 8]);
 502         chacha.process_in_place(packet);
 503         msgs::DecodedOnionErrorPacket::read(&mut Cursor::new(packet))
 504 }
 505
 506 /// Process failure we got back from upstream on a payment we sent (implying htlc_source is an
 507 /// OutboundRoute).
 508 #[inline]
 509 pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
 510         secp_ctx: &Secp256k1<T>, logger: &L, htlc_source: &HTLCSource, mut encrypted_packet: Vec<u8>,
 511 ) -> DecodedOnionFailure
 512 where
 513         L::Target: Logger,
 514 {
 515         let (path, session_priv, first_hop_htlc_msat) = match htlc_source {
 516                 HTLCSource::OutboundRoute {
 517                         ref path, ref session_priv, ref first_hop_htlc_msat, ..
 518                 } => (path, session_priv, first_hop_htlc_msat),
 519                 _ => {
 520                         unreachable!()
 521                 },
 522         };
 523
 524         // Learnings from the HTLC failure to inform future payment retries and scoring.
 525         struct FailureLearnings {
 526                 network_update: Option<NetworkUpdate>,
 527                 short_channel_id: Option<u64>,
 528                 payment_failed_permanently: bool,
 529                 failed_within_blinded_path: bool,
 530         }
 531         let mut res: Option<FailureLearnings> = None;
 532         let mut htlc_msat = *first_hop_htlc_msat;
 533         let mut error_code_ret = None;
 534         let mut error_packet_ret = None;
 535         let mut is_from_final_node = false;
 536
 537         const BADONION: u16 = 0x8000;
 538         const PERM: u16 = 0x4000;
 539         const NODE: u16 = 0x2000;
 540         const UPDATE: u16 = 0x1000;
 541
 542         // Handle packed channel/node updates for passing back for the route handler
 543         let callback = |shared_secret, _, _, route_hop_opt: Option<&RouteHop>, route_hop_idx| {
 544                 if res.is_some() {
 545                         return;
 546                 }
 547
 548                 let route_hop = match route_hop_opt {
 549                         Some(hop) => hop,
 550                         None => {
 551                                 // Got an error from within a blinded route.
 552                                 error_code_ret = Some(BADONION | PERM | 24); // invalid_onion_blinding
 553                                 error_packet_ret = Some(vec![0; 32]);
 554                                 res = Some(FailureLearnings {
 555                                         network_update: None,
 556                                         short_channel_id: None,
 557                                         payment_failed_permanently: false,
 558                                         failed_within_blinded_path: true,
 559                                 });
 560                                 return;
 561                         },
 562                 };
 563
 564                 // The failing hop includes either the inbound channel to the recipient or the outbound channel
 565                 // from the current hop (i.e., the next hop's inbound channel).
 566                 let num_blinded_hops = path.blinded_tail.as_ref().map_or(0, |bt| bt.hops.len());
 567                 // For 1-hop blinded paths, the final `path.hops` entry is the recipient.
 568                 is_from_final_node = route_hop_idx + 1 == path.hops.len() && num_blinded_hops <= 1;
 569                 let failing_route_hop = if is_from_final_node {
 570                         route_hop
 571                 } else {
 572                         match path.hops.get(route_hop_idx + 1) {
 573                                 Some(hop) => hop,
 574                                 None => {
 575                                         // The failing hop is within a multi-hop blinded path.
 576                                         #[cfg(not(test))]
 577                                         {
 578                                                 error_code_ret = Some(BADONION | PERM | 24); // invalid_onion_blinding
 579                                                 error_packet_ret = Some(vec![0; 32]);
 580                                         }
 581                                         #[cfg(test)]
 582                                         {
 583                                                 // Actually parse the onion error data in tests so we can check that blinded hops fail
 584                                                 // back correctly.
 585                                                 let err_packet =
 586                                                         decrypt_onion_error_packet(&mut encrypted_packet, shared_secret)
 587                                                                 .unwrap();
 588                                                 error_code_ret = Some(u16::from_be_bytes(
 589                                                         err_packet.failuremsg.get(0..2).unwrap().try_into().unwrap(),
 590                                                 ));
 591                                                 error_packet_ret = Some(err_packet.failuremsg[2..].to_vec());
 592                                         }
 593
 594                                         res = Some(FailureLearnings {
 595                                                 network_update: None,
 596                                                 short_channel_id: None,
 597                                                 payment_failed_permanently: false,
 598                                                 failed_within_blinded_path: true,
 599                                         });
 600                                         return;
 601                                 },
 602                         }
 603                 };
 604
 605                 let amt_to_forward = htlc_msat - route_hop.fee_msat;
 606                 htlc_msat = amt_to_forward;
 607
 608                 let err_packet = match decrypt_onion_error_packet(&mut encrypted_packet, shared_secret) {
 609                         Ok(p) => p,
 610                         Err(_) => return,
 611                 };
 612                 let um = gen_um_from_shared_secret(shared_secret.as_ref());
 613                 let mut hmac = HmacEngine::<Sha256>::new(&um);
 614                 hmac.input(&err_packet.encode()[32..]);
 615
 616                 if !fixed_time_eq(&Hmac::from_engine(hmac).to_byte_array(), &err_packet.hmac) {
 617                         return;
 618                 }
 619                 let error_code_slice = match err_packet.failuremsg.get(0..2) {
 620                         Some(s) => s,
 621                         None => {
 622                                 // Useless packet that we can't use but it passed HMAC, so it definitely came from the peer
 623                                 // in question
 624                                 let network_update = Some(NetworkUpdate::NodeFailure {
 625                                         node_id: route_hop.pubkey,
 626                                         is_permanent: true,
 627                                 });
 628                                 let short_channel_id = Some(route_hop.short_channel_id);
 629                                 res = Some(FailureLearnings {
 630                                         network_update,
 631                                         short_channel_id,
 632                                         payment_failed_permanently: is_from_final_node,
 633                                         failed_within_blinded_path: false,
 634                                 });
 635                                 return;
 636                         },
 637                 };
 638
 639                 let error_code = u16::from_be_bytes(error_code_slice.try_into().expect("len is 2"));
 640                 error_code_ret = Some(error_code);
 641                 error_packet_ret = Some(err_packet.failuremsg[2..].to_vec());
 642
 643                 let (debug_field, debug_field_size) = errors::get_onion_debug_field(error_code);
 644
 645                 // indicate that payment parameter has failed and no need to update Route object
 646                 let payment_failed = match error_code & 0xff {
 647                         15 | 16 | 17 | 18 | 19 | 23 => true,
 648                         _ => false,
 649                 } && is_from_final_node; // PERM bit observed below even if this error is from the intermediate nodes
 650
 651                 let mut network_update = None;
 652                 let mut short_channel_id = None;
 653
 654                 if error_code & BADONION == BADONION {
 655                         // If the error code has the BADONION bit set, always blame the channel from the node
 656                         // "originating" the error to its next hop. The "originator" is ultimately actually claiming
 657                         // that its counterparty is the one who is failing the HTLC.
 658                         // If the "originator" here isn't lying we should really mark the next-hop node as failed
 659                         // entirely, but we can't be confident in that, as it would allow any node to get us to
 660                         // completely ban one of its counterparties. Instead, we simply remove the channel in
 661                         // question.
 662                         network_update = Some(NetworkUpdate::ChannelFailure {
 663                                 short_channel_id: failing_route_hop.short_channel_id,
 664                                 is_permanent: true,
 665                         });
 666                 } else if error_code & NODE == NODE {
 667                         let is_permanent = error_code & PERM == PERM;
 668                         network_update =
 669                                 Some(NetworkUpdate::NodeFailure { node_id: route_hop.pubkey, is_permanent });
 670                         short_channel_id = Some(route_hop.short_channel_id);
 671                 } else if error_code & PERM == PERM {
 672                         if !payment_failed {
 673                                 network_update = Some(NetworkUpdate::ChannelFailure {
 674                                         short_channel_id: failing_route_hop.short_channel_id,
 675                                         is_permanent: true,
 676                                 });
 677                                 short_channel_id = Some(failing_route_hop.short_channel_id);
 678                         }
 679                 } else if error_code & UPDATE == UPDATE {
 680                         if let Some(update_len_slice) =
 681                                 err_packet.failuremsg.get(debug_field_size + 2..debug_field_size + 4)
 682                         {
 683                                 let update_len =
 684                                         u16::from_be_bytes(update_len_slice.try_into().expect("len is 2")) as usize;
 685                                 if let Some(mut update_slice) = err_packet
 686                                         .failuremsg
 687                                         .get(debug_field_size + 4..debug_field_size + 4 + update_len)
 688                                 {
 689                                         // Historically, the BOLTs were unclear if the message type
 690                                         // bytes should be included here or not. The BOLTs have now
 691                                         // been updated to indicate that they *are* included, but many
 692                                         // nodes still send messages without the type bytes, so we
 693                                         // support both here.
 694                                         // TODO: Switch to hard require the type prefix, as the current
 695                                         // permissiveness introduces the (although small) possibility
 696                                         // that we fail to decode legitimate channel updates that
 697                                         // happen to start with ChannelUpdate::TYPE, i.e., [0x01, 0x02].
 698                                         if update_slice.len() > 2
 699                                                 && update_slice[0..2] == msgs::ChannelUpdate::TYPE.to_be_bytes()
 700                                         {
 701                                                 update_slice = &update_slice[2..];
 702                                         } else {
 703                                                 log_trace!(logger, "Failure provided features a channel update without type prefix. Deprecated, but allowing for now.");
 704                                         }
 705                                         let update_opt = msgs::ChannelUpdate::read(&mut Cursor::new(&update_slice));
 706                                         if update_opt.is_ok() || update_slice.is_empty() {
 707                                                 // if channel_update should NOT have caused the failure:
 708                                                 // MAY treat the channel_update as invalid.
 709                                                 let is_chan_update_invalid = match error_code & 0xff {
 710                                                         7 => false,
 711                                                         11 => {
 712                                                                 update_opt.is_ok()
 713                                                                         && amt_to_forward
 714                                                                                 > update_opt.as_ref().unwrap().contents.htlc_minimum_msat
 715                                                         },
 716                                                         12 => {
 717                                                                 update_opt.is_ok()
 718                                                                         && amt_to_forward
 719                                                                                 .checked_mul(
 720                                                                                         update_opt
 721                                                                                                 .as_ref()
 722                                                                                                 .unwrap()
 723                                                                                                 .contents
 724                                                                                                 .fee_proportional_millionths as u64,
 725                                                                                 )
 726                                                                                 .map(|prop_fee| prop_fee / 1_000_000)
 727                                                                                 .and_then(|prop_fee| {
 728                                                                                         prop_fee.checked_add(
 729                                                                                                 update_opt.as_ref().unwrap().contents.fee_base_msat
 730                                                                                                         as u64,
 731                                                                                         )
 732                                                                                 })
 733                                                                                 .map(|fee_msats| route_hop.fee_msat >= fee_msats)
 734                                                                                 .unwrap_or(false)
 735                                                         },
 736                                                         13 => {
 737                                                                 update_opt.is_ok()
 738                                                                         && route_hop.cltv_expiry_delta as u16
 739                                                                                 >= update_opt.as_ref().unwrap().contents.cltv_expiry_delta
 740                                                         },
 741                                                         14 => false, // expiry_too_soon; always valid?
 742                                                         20 => update_opt.as_ref().unwrap().contents.flags & 2 == 0,
 743                                                         _ => false, // unknown error code; take channel_update as valid
 744                                                 };
 745                                                 if is_chan_update_invalid {
 746                                                         // This probably indicates the node which forwarded
 747                                                         // to the node in question corrupted something.
 748                                                         network_update = Some(NetworkUpdate::ChannelFailure {
 749                                                                 short_channel_id: route_hop.short_channel_id,
 750                                                                 is_permanent: true,
 751                                                         });
 752                                                 } else {
 753                                                         if let Ok(chan_update) = update_opt {
 754                                                                 // Make sure the ChannelUpdate contains the expected
 755                                                                 // short channel id.
 756                                                                 if failing_route_hop.short_channel_id
 757                                                                         == chan_update.contents.short_channel_id
 758                                                                 {
 759                                                                         short_channel_id = Some(failing_route_hop.short_channel_id);
 760                                                                 } else {
 761                                                                         log_info!(logger, "Node provided a channel_update for which it was not authoritative, ignoring.");
 762                                                                 }
 763                                                                 network_update =
 764                                                                         Some(NetworkUpdate::ChannelUpdateMessage { msg: chan_update })
 765                                                         } else {
 766                                                                 // The node in question intentionally encoded a 0-length channel update. This is
 767                                                                 // likely due to https://github.com/ElementsProject/lightning/issues/6200.
 768                                                                 short_channel_id = Some(failing_route_hop.short_channel_id);
 769                                                                 network_update = Some(NetworkUpdate::ChannelFailure {
 770                                                                         short_channel_id: failing_route_hop.short_channel_id,
 771                                                                         is_permanent: false,
 772                                                                 });
 773                                                         }
 774                                                 };
 775                                         } else {
 776                                                 // If the channel_update had a non-zero length (i.e. was
 777                                                 // present) but we couldn't read it, treat it as a total
 778                                                 // node failure.
 779                                                 log_info!(
 780                                                         logger,
 781                                                         "Failed to read a channel_update of len {} in an onion",
 782                                                         update_slice.len()
 783                                                 );
 784                                         }
 785                                 }
 786                         }
 787                         if network_update.is_none() {
 788                                 // They provided an UPDATE which was obviously bogus, not worth
 789                                 // trying to relay through them anymore.
 790                                 network_update = Some(NetworkUpdate::NodeFailure {
 791                                         node_id: route_hop.pubkey,
 792                                         is_permanent: true,
 793                                 });
 794                         }
 795                         if short_channel_id.is_none() {
 796                                 short_channel_id = Some(route_hop.short_channel_id);
 797                         }
 798                 } else if payment_failed {
 799                         // Only blame the hop when a value in the HTLC doesn't match the corresponding value in the
 800                         // onion.
 801                         short_channel_id = match error_code & 0xff {
 802                                 18 | 19 => Some(route_hop.short_channel_id),
 803                                 _ => None,
 804                         };
 805                 } else {
 806                         // We can't understand their error messages and they failed to forward...they probably can't
 807                         // understand our forwards so it's really not worth trying any further.
 808                         network_update =
 809                                 Some(NetworkUpdate::NodeFailure { node_id: route_hop.pubkey, is_permanent: true });
 810                         short_channel_id = Some(route_hop.short_channel_id);
 811                 }
 812
 813                 res = Some(FailureLearnings {
 814                         network_update,
 815                         short_channel_id,
 816                         payment_failed_permanently: error_code & PERM == PERM && is_from_final_node,
 817                         failed_within_blinded_path: false,
 818                 });
 819
 820                 let (description, title) = errors::get_onion_error_description(error_code);
 821                 if debug_field_size > 0 && err_packet.failuremsg.len() >= 4 + debug_field_size {
 822                         log_info!(
 823                                 logger,
 824                                 "Onion Error[from {}: {}({:#x}) {}({})] {}",
 825                                 route_hop.pubkey,
 826                                 title,
 827                                 error_code,
 828                                 debug_field,
 829                                 log_bytes!(&err_packet.failuremsg[4..4 + debug_field_size]),
 830                                 description
 831                         );
 832                 } else {
 833                         log_info!(
 834                                 logger,
 835                                 "Onion Error[from {}: {}({:#x})] {}",
 836                                 route_hop.pubkey,
 837                                 title,
 838                                 error_code,
 839                                 description
 840                         );
 841                 }
 842         };
 843
 844         construct_onion_keys_callback(secp_ctx, &path, session_priv, callback)
 845                 .expect("Route that we sent via spontaneously grew invalid keys in the middle of it?");
 846
 847         if let Some(FailureLearnings {
 848                 network_update,
 849                 short_channel_id,
 850                 payment_failed_permanently,
 851                 failed_within_blinded_path,
 852         }) = res
 853         {
 854                 DecodedOnionFailure {
 855                         network_update,
 856                         short_channel_id,
 857                         payment_failed_permanently,
 858                         failed_within_blinded_path,
 859                         #[cfg(test)]
 860                         onion_error_code: error_code_ret,
 861                         #[cfg(test)]
 862                         onion_error_data: error_packet_ret,
 863                 }
 864         } else {
 865                 // only not set either packet unparseable or hmac does not match with any
 866                 // payment not retryable only when garbage is from the final node
 867                 DecodedOnionFailure {
 868                         network_update: None,
 869                         short_channel_id: None,
 870                         payment_failed_permanently: is_from_final_node,
 871                         failed_within_blinded_path: false,
 872                         #[cfg(test)]
 873                         onion_error_code: None,
 874                         #[cfg(test)]
 875                         onion_error_data: None,
 876                 }
 877         }
 878 }
 879
 880 #[derive(Clone)] // See Channel::revoke_and_ack for why, tl;dr: Rust bug
 881 #[cfg_attr(test, derive(PartialEq))]
 882 pub(super) struct HTLCFailReason(HTLCFailReasonRepr);
 883
 884 #[derive(Clone)] // See Channel::revoke_and_ack for why, tl;dr: Rust bug
 885 #[cfg_attr(test, derive(PartialEq))]
 886 enum HTLCFailReasonRepr {
 887         LightningError { err: msgs::OnionErrorPacket },
 888         Reason { failure_code: u16, data: Vec<u8> },
 889 }
 890
 891 impl core::fmt::Debug for HTLCFailReason {
 892         fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
 893                 match self.0 {
 894                         HTLCFailReasonRepr::Reason { ref failure_code, .. } => {
 895                                 write!(f, "HTLC error code {}", failure_code)
 896                         },
 897                         HTLCFailReasonRepr::LightningError { .. } => {
 898                                 write!(f, "pre-built LightningError")
 899                         },
 900                 }
 901         }
 902 }
 903
 904 impl Writeable for HTLCFailReason {
 905         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), crate::io::Error> {
 906                 self.0.write(writer)
 907         }
 908 }
 909 impl Readable for HTLCFailReason {
 910         fn read<R: Read>(reader: &mut R) -> Result<Self, msgs::DecodeError> {
 911                 Ok(Self(Readable::read(reader)?))
 912         }
 913 }
 914
 915 impl_writeable_tlv_based_enum!(HTLCFailReasonRepr,
 916         (0, LightningError) => {
 917                 (0, err, required),
 918         },
 919         (1, Reason) => {
 920                 (0, failure_code, required),
 921                 (2, data, required_vec),
 922         },
 923 ;);
 924
 925 impl HTLCFailReason {
 926         #[rustfmt::skip]
 927         pub(super) fn reason(failure_code: u16, data: Vec<u8>) -> Self {
 928                 const BADONION: u16 = 0x8000;
 929                 const PERM: u16 = 0x4000;
 930                 const NODE: u16 = 0x2000;
 931                 const UPDATE: u16 = 0x1000;
 932
 933                      if failure_code == 1  | PERM { debug_assert!(data.is_empty()) }
 934                 else if failure_code == 2  | NODE { debug_assert!(data.is_empty()) }
 935                 else if failure_code == 2  | PERM | NODE { debug_assert!(data.is_empty()) }
 936                 else if failure_code == 3  | PERM | NODE { debug_assert!(data.is_empty()) }
 937                 else if failure_code == 4  | BADONION | PERM { debug_assert_eq!(data.len(), 32) }
 938                 else if failure_code == 5  | BADONION | PERM { debug_assert_eq!(data.len(), 32) }
 939                 else if failure_code == 6  | BADONION | PERM { debug_assert_eq!(data.len(), 32) }
 940                 else if failure_code == 7  | UPDATE {
 941                         debug_assert_eq!(data.len() - 2, u16::from_be_bytes(data[0..2].try_into().unwrap()) as usize) }
 942                 else if failure_code == 8  | PERM { debug_assert!(data.is_empty()) }
 943                 else if failure_code == 9  | PERM { debug_assert!(data.is_empty()) }
 944                 else if failure_code == 10 | PERM { debug_assert!(data.is_empty()) }
 945                 else if failure_code == 11 | UPDATE {
 946                         debug_assert_eq!(data.len() - 2 - 8, u16::from_be_bytes(data[8..10].try_into().unwrap()) as usize) }
 947                 else if failure_code == 12 | UPDATE {
 948                         debug_assert_eq!(data.len() - 2 - 8, u16::from_be_bytes(data[8..10].try_into().unwrap()) as usize) }
 949                 else if failure_code == 13 | UPDATE {
 950                         debug_assert_eq!(data.len() - 2 - 4, u16::from_be_bytes(data[4..6].try_into().unwrap()) as usize) }
 951                 else if failure_code == 14 | UPDATE {
 952                         debug_assert_eq!(data.len() - 2, u16::from_be_bytes(data[0..2].try_into().unwrap()) as usize) }
 953                 else if failure_code == 15 | PERM { debug_assert_eq!(data.len(), 12) }
 954                 else if failure_code == 18 { debug_assert_eq!(data.len(), 4) }
 955                 else if failure_code == 19 { debug_assert_eq!(data.len(), 8) }
 956                 else if failure_code == 20 | UPDATE {
 957                         debug_assert_eq!(data.len() - 2 - 2, u16::from_be_bytes(data[2..4].try_into().unwrap()) as usize) }
 958                 else if failure_code == 21 { debug_assert!(data.is_empty()) }
 959                 else if failure_code == 22 | PERM { debug_assert!(data.len() <= 11) }
 960                 else if failure_code == 23 { debug_assert!(data.is_empty()) }
 961                 else if failure_code & BADONION != 0 {
 962                         // We set some bogus BADONION failure codes in test, so ignore unknown ones.
 963                 }
 964                 else { debug_assert!(false, "Unknown failure code: {}", failure_code) }
 965
 966                 Self(HTLCFailReasonRepr::Reason { failure_code, data })
 967         }
 968
 969         pub(super) fn from_failure_code(failure_code: u16) -> Self {
 970                 Self::reason(failure_code, Vec::new())
 971         }
 972
 973         pub(super) fn from_msg(msg: &msgs::UpdateFailHTLC) -> Self {
 974                 Self(HTLCFailReasonRepr::LightningError { err: msg.reason.clone() })
 975         }
 976
 977         pub(super) fn get_encrypted_failure_packet(
 978                 &self, incoming_packet_shared_secret: &[u8; 32], phantom_shared_secret: &Option<[u8; 32]>,
 979         ) -> msgs::OnionErrorPacket {
 980                 match self.0 {
 981                         HTLCFailReasonRepr::Reason { ref failure_code, ref data } => {
 982                                 if let Some(phantom_ss) = phantom_shared_secret {
 983                                         let phantom_packet =
 984                                                 build_failure_packet(phantom_ss, *failure_code, &data[..]).encode();
 985                                         let encrypted_phantom_packet =
 986                                                 encrypt_failure_packet(phantom_ss, &phantom_packet);
 987                                         encrypt_failure_packet(
 988                                                 incoming_packet_shared_secret,
 989                                                 &encrypted_phantom_packet.data[..],
 990                                         )
 991                                 } else {
 992                                         let packet = build_failure_packet(
 993                                                 incoming_packet_shared_secret,
 994                                                 *failure_code,
 995                                                 &data[..],
 996                                         )
 997                                         .encode();
 998                                         encrypt_failure_packet(incoming_packet_shared_secret, &packet)
 999                                 }
1000                         },
1001                         HTLCFailReasonRepr::LightningError { ref err } => {
1002                                 encrypt_failure_packet(incoming_packet_shared_secret, &err.data)
1003                         },
1004                 }
1005         }
1006
1007         pub(super) fn decode_onion_failure<T: secp256k1::Signing, L: Deref>(
1008                 &self, secp_ctx: &Secp256k1<T>, logger: &L, htlc_source: &HTLCSource,
1009         ) -> DecodedOnionFailure
1010         where
1011                 L::Target: Logger,
1012         {
1013                 match self.0 {
1014                         HTLCFailReasonRepr::LightningError { ref err } => {
1015                                 process_onion_failure(secp_ctx, logger, &htlc_source, err.data.clone())
1016                         },
1017                         #[allow(unused)]
1018                         HTLCFailReasonRepr::Reason { ref failure_code, ref data, .. } => {
1019                                 // we get a fail_malformed_htlc from the first hop
1020                                 // TODO: We'd like to generate a NetworkUpdate for temporary
1021                                 // failures here, but that would be insufficient as find_route
1022                                 // generally ignores its view of our own channels as we provide them via
1023                                 // ChannelDetails.
1024                                 if let &HTLCSource::OutboundRoute { ref path, .. } = htlc_source {
1025                                         DecodedOnionFailure {
1026                                                 network_update: None,
1027                                                 payment_failed_permanently: false,
1028                                                 short_channel_id: Some(path.hops[0].short_channel_id),
1029                                                 failed_within_blinded_path: false,
1030                                                 #[cfg(test)]
1031                                                 onion_error_code: Some(*failure_code),
1032                                                 #[cfg(test)]
1033                                                 onion_error_data: Some(data.clone()),
1034                                         }
1035                                 } else {
1036                                         unreachable!();
1037                                 }
1038                         },
1039                 }
1040         }
1041 }
1042
1043 /// Allows `decode_next_hop` to return the next hop packet bytes for either payments or onion
1044 /// message forwards.
1045 pub(crate) trait NextPacketBytes: AsMut<[u8]> {
1046         fn new(len: usize) -> Self;
1047 }
1048
1049 impl NextPacketBytes for FixedSizeOnionPacket {
1050         fn new(_len: usize) -> Self {
1051                 Self([0 as u8; ONION_DATA_LEN])
1052         }
1053 }
1054
1055 impl NextPacketBytes for Vec<u8> {
1056         fn new(len: usize) -> Self {
1057                 vec![0 as u8; len]
1058         }
1059 }
1060
1061 /// Data decrypted from a payment's onion payload.
1062 pub(crate) enum Hop {
1063         /// This onion payload was for us, not for forwarding to a next-hop. Contains information for
1064         /// verifying the incoming payment.
1065         Receive(msgs::InboundOnionPayload),
1066         /// This onion payload needs to be forwarded to a next-hop.
1067         Forward {
1068                 /// Onion payload data used in forwarding the payment.
1069                 next_hop_data: msgs::InboundOnionPayload,
1070                 /// HMAC of the next hop's onion packet.
1071                 next_hop_hmac: [u8; 32],
1072                 /// Bytes of the onion packet we're forwarding.
1073                 new_packet_bytes: [u8; ONION_DATA_LEN],
1074         },
1075 }
1076
1077 impl Hop {
1078         pub(crate) fn is_intro_node_blinded_forward(&self) -> bool {
1079                 match self {
1080                         Self::Forward {
1081                                 next_hop_data:
1082                                         msgs::InboundOnionPayload::BlindedForward {
1083                                                 intro_node_blinding_point: Some(_), ..
1084                                         },
1085                                 ..
1086                         } => true,
1087                         _ => false,
1088                 }
1089         }
1090 }
1091
1092 /// Error returned when we fail to decode the onion packet.
1093 #[derive(Debug)]
1094 pub(crate) enum OnionDecodeErr {
1095         /// The HMAC of the onion packet did not match the hop data.
1096         Malformed { err_msg: &'static str, err_code: u16 },
1097         /// We failed to decode the onion payload.
1098         Relay { err_msg: &'static str, err_code: u16 },
1099 }
1100
1101 pub(crate) fn decode_next_payment_hop<NS: Deref>(
1102         shared_secret: [u8; 32], hop_data: &[u8], hmac_bytes: [u8; 32], payment_hash: PaymentHash,
1103         blinding_point: Option<PublicKey>, node_signer: &NS,
1104 ) -> Result<Hop, OnionDecodeErr>
1105 where
1106         NS::Target: NodeSigner,
1107 {
1108         match decode_next_hop(
1109                 shared_secret,
1110                 hop_data,
1111                 hmac_bytes,
1112                 Some(payment_hash),
1113                 (blinding_point, node_signer),
1114         ) {
1115                 Ok((next_hop_data, None)) => Ok(Hop::Receive(next_hop_data)),
1116                 Ok((next_hop_data, Some((next_hop_hmac, FixedSizeOnionPacket(new_packet_bytes))))) => {
1117                         Ok(Hop::Forward { next_hop_data, next_hop_hmac, new_packet_bytes })
1118                 },
1119                 Err(e) => Err(e),
1120         }
1121 }
1122
1123 /// Build a payment onion, returning the first hop msat and cltv values as well.
1124 /// `cur_block_height` should be set to the best known block height + 1.
1125 pub fn create_payment_onion<T: secp256k1::Signing>(
1126         secp_ctx: &Secp256k1<T>, path: &Path, session_priv: &SecretKey, total_msat: u64,
1127         recipient_onion: RecipientOnionFields, cur_block_height: u32, payment_hash: &PaymentHash,
1128         keysend_preimage: &Option<PaymentPreimage>, prng_seed: [u8; 32],
1129 ) -> Result<(msgs::OnionPacket, u64, u32), APIError> {
1130         let onion_keys = construct_onion_keys(&secp_ctx, &path, &session_priv).map_err(|_| {
1131                 APIError::InvalidRoute { err: "Pubkey along hop was maliciously selected".to_owned() }
1132         })?;
1133         let (onion_payloads, htlc_msat, htlc_cltv) = build_onion_payloads(
1134                 &path,
1135                 total_msat,
1136                 recipient_onion,
1137                 cur_block_height,
1138                 keysend_preimage,
1139         )?;
1140         let onion_packet = construct_onion_packet(onion_payloads, onion_keys, prng_seed, payment_hash)
1141                 .map_err(|_| APIError::InvalidRoute {
1142                         err: "Route size too large considering onion data".to_owned(),
1143                 })?;
1144         Ok((onion_packet, htlc_msat, htlc_cltv))
1145 }
1146
1147 pub(crate) fn decode_next_untagged_hop<T, R: ReadableArgs<T>, N: NextPacketBytes>(
1148         shared_secret: [u8; 32], hop_data: &[u8], hmac_bytes: [u8; 32], read_args: T,
1149 ) -> Result<(R, Option<([u8; 32], N)>), OnionDecodeErr> {
1150         decode_next_hop(shared_secret, hop_data, hmac_bytes, None, read_args)
1151 }
1152
1153 fn decode_next_hop<T, R: ReadableArgs<T>, N: NextPacketBytes>(
1154         shared_secret: [u8; 32], hop_data: &[u8], hmac_bytes: [u8; 32],
1155         payment_hash: Option<PaymentHash>, read_args: T,
1156 ) -> Result<(R, Option<([u8; 32], N)>), OnionDecodeErr> {
1157         let (rho, mu) = gen_rho_mu_from_shared_secret(&shared_secret);
1158         let mut hmac = HmacEngine::<Sha256>::new(&mu);
1159         hmac.input(hop_data);
1160         if let Some(tag) = payment_hash {
1161                 hmac.input(&tag.0[..]);
1162         }
1163         if !fixed_time_eq(&Hmac::from_engine(hmac).to_byte_array(), &hmac_bytes) {
1164                 return Err(OnionDecodeErr::Malformed {
1165                         err_msg: "HMAC Check failed",
1166                         err_code: 0x8000 | 0x4000 | 5,
1167                 });
1168         }
1169
1170         let mut chacha = ChaCha20::new(&rho, &[0u8; 8]);
1171         let mut chacha_stream = ChaChaReader { chacha: &mut chacha, read: Cursor::new(&hop_data[..]) };
1172         match R::read(&mut chacha_stream, read_args) {
1173                 Err(err) => {
1174                         let error_code = match err {
1175                                 // Unknown realm byte
1176                                 msgs::DecodeError::UnknownVersion => 0x4000 | 1,
1177                                 // invalid_onion_payload
1178                                 msgs::DecodeError::UnknownRequiredFeature
1179                                 | msgs::DecodeError::InvalidValue
1180                                 | msgs::DecodeError::ShortRead => 0x4000 | 22,
1181                                 // Should never happen
1182                                 _ => 0x2000 | 2,
1183                         };
1184                         return Err(OnionDecodeErr::Relay {
1185                                 err_msg: "Unable to decode our hop data",
1186                                 err_code: error_code,
1187                         });
1188                 },
1189                 Ok(msg) => {
1190                         let mut hmac = [0; 32];
1191                         if let Err(_) = chacha_stream.read_exact(&mut hmac[..]) {
1192                                 return Err(OnionDecodeErr::Relay {
1193                                         err_msg: "Unable to decode our hop data",
1194                                         err_code: 0x4000 | 22,
1195                                 });
1196                         }
1197                         if hmac == [0; 32] {
1198                                 #[cfg(test)]
1199                                 {
1200                                         if chacha_stream.read.position() < hop_data.len() as u64 - 64 {
1201                                                 // In tests, make sure that the initial onion packet data is, at least, non-0.
1202                                                 // We could do some fancy randomness test here, but, ehh, whatever.
1203                                                 // This checks for the issue where you can calculate the path length given the
1204                                                 // onion data as all the path entries that the originator sent will be here
1205                                                 // as-is (and were originally 0s).
1206                                                 // Of course reverse path calculation is still pretty easy given naive routing
1207                                                 // algorithms, but this fixes the most-obvious case.
1208                                                 let mut next_bytes = [0; 32];
1209                                                 chacha_stream.read_exact(&mut next_bytes).unwrap();
1210                                                 assert_ne!(next_bytes[..], [0; 32][..]);
1211                                                 chacha_stream.read_exact(&mut next_bytes).unwrap();
1212                                                 assert_ne!(next_bytes[..], [0; 32][..]);
1213                                         }
1214                                 }
1215                                 return Ok((msg, None)); // We are the final destination for this packet
1216                         } else {
1217                                 let mut new_packet_bytes = N::new(hop_data.len());
1218                                 let read_pos = hop_data.len() - chacha_stream.read.position() as usize;
1219                                 chacha_stream.read_exact(&mut new_packet_bytes.as_mut()[..read_pos]).unwrap();
1220                                 #[cfg(debug_assertions)]
1221                                 {
1222                                         // Check two things:
1223                                         // a) that the behavior of our stream here will return Ok(0) even if the TLV
1224                                         //    read above emptied out our buffer and the unwrap() wont needlessly panic
1225                                         // b) that we didn't somehow magically end up with extra data.
1226                                         let mut t = [0; 1];
1227                                         debug_assert!(chacha_stream.read(&mut t).unwrap() == 0);
1228                                 }
1229                                 // Once we've emptied the set of bytes our peer gave us, encrypt 0 bytes until we
1230                                 // fill the onion hop data we'll forward to our next-hop peer.
1231                                 chacha_stream.chacha.process_in_place(&mut new_packet_bytes.as_mut()[read_pos..]);
1232                                 return Ok((msg, Some((hmac, new_packet_bytes)))); // This packet needs forwarding
1233                         }
1234                 },
1235         }
1236 }
1237
1238 #[cfg(test)]
1239 mod tests {
1240         use crate::io;
1241         use crate::ln::features::{ChannelFeatures, NodeFeatures};
1242         use crate::ln::msgs;
1243         use crate::ln::types::PaymentHash;
1244         use crate::routing::router::{Path, Route, RouteHop};
1245         use crate::util::ser::{VecWriter, Writeable, Writer};
1246
1247         #[allow(unused_imports)]
1248         use crate::prelude::*;
1249
1250         use bitcoin::hashes::hex::FromHex;
1251         use bitcoin::secp256k1::Secp256k1;
1252         use bitcoin::secp256k1::{PublicKey, SecretKey};
1253
1254         use super::OnionKeys;
1255
1256         fn get_test_session_key() -> SecretKey {
1257                 let hex = "4141414141414141414141414141414141414141414141414141414141414141";
1258                 SecretKey::from_slice(&<Vec<u8>>::from_hex(hex).unwrap()[..]).unwrap()
1259         }
1260
1261         fn build_test_onion_keys() -> Vec<OnionKeys> {
1262                 // Keys from BOLT 4, used in both test vector tests
1263                 let secp_ctx = Secp256k1::new();
1264
1265                 let route = Route {
1266                         paths: vec![Path { hops: vec![
1267                                         RouteHop {
1268                                                 pubkey: PublicKey::from_slice(&<Vec<u8>>::from_hex("02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619").unwrap()[..]).unwrap(),
1269                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
1270                                                 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.
1271                                         },
1272                                         RouteHop {
1273                                                 pubkey: PublicKey::from_slice(&<Vec<u8>>::from_hex("0324653eac434488002cc06bbfb7f10fe18991e35f9fe4302dbea6d2353dc0ab1c").unwrap()[..]).unwrap(),
1274                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
1275                                                 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.
1276                                         },
1277                                         RouteHop {
1278                                                 pubkey: PublicKey::from_slice(&<Vec<u8>>::from_hex("027f31ebc5462c1fdce1b737ecff52d37d75dea43ce11c74d25aa297165faa2007").unwrap()[..]).unwrap(),
1279                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
1280                                                 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.
1281                                         },
1282                                         RouteHop {
1283                                                 pubkey: PublicKey::from_slice(&<Vec<u8>>::from_hex("032c0b7cf95324a07d05398b240174dc0c2be444d96b159aa6c7f7b1e668680991").unwrap()[..]).unwrap(),
1284                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
1285                                                 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.
1286                                         },
1287                                         RouteHop {
1288                                                 pubkey: PublicKey::from_slice(&<Vec<u8>>::from_hex("02edabbd16b41c8371b92ef2f04c1185b4f03b6dcd52ba9b78d9d7c89c8f221145").unwrap()[..]).unwrap(),
1289                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
1290                                                 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.
1291                                         },
1292                         ], blinded_tail: None }],
1293                         route_params: None,
1294                 };
1295
1296                 let onion_keys =
1297                         super::construct_onion_keys(&secp_ctx, &route.paths[0], &get_test_session_key())
1298                                 .unwrap();
1299                 assert_eq!(onion_keys.len(), route.paths[0].hops.len());
1300                 onion_keys
1301         }
1302
1303         #[test]
1304         fn onion_vectors() {
1305                 let onion_keys = build_test_onion_keys();
1306
1307                 // Test generation of ephemeral keys and secrets. These values used to be part of the BOLT4
1308                 // test vectors, but have since been removed. We keep them as they provide test coverage.
1309                 let hex = "53eb63ea8a3fec3b3cd433b85cd62a4b145e1dda09391b348c4e1cd36a03ea66";
1310                 assert_eq!(
1311                         onion_keys[0].shared_secret.secret_bytes(),
1312                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1313                 );
1314
1315                 let hex = "2ec2e5da605776054187180343287683aa6a51b4b1c04d6dd49c45d8cffb3c36";
1316                 assert_eq!(onion_keys[0].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
1317
1318                 let hex = "02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619";
1319                 assert_eq!(
1320                         onion_keys[0].ephemeral_pubkey.serialize()[..],
1321                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1322                 );
1323
1324                 let hex = "ce496ec94def95aadd4bec15cdb41a740c9f2b62347c4917325fcc6fb0453986";
1325                 assert_eq!(onion_keys[0].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1326
1327                 let hex = "b57061dc6d0a2b9f261ac410c8b26d64ac5506cbba30267a649c28c179400eba";
1328                 assert_eq!(onion_keys[0].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1329
1330                 let hex = "a6519e98832a0b179f62123b3567c106db99ee37bef036e783263602f3488fae";
1331                 assert_eq!(
1332                         onion_keys[1].shared_secret.secret_bytes(),
1333                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1334                 );
1335
1336                 let hex = "bf66c28bc22e598cfd574a1931a2bafbca09163df2261e6d0056b2610dab938f";
1337                 assert_eq!(onion_keys[1].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
1338
1339                 let hex = "028f9438bfbf7feac2e108d677e3a82da596be706cc1cf342b75c7b7e22bf4e6e2";
1340                 assert_eq!(
1341                         onion_keys[1].ephemeral_pubkey.serialize()[..],
1342                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1343                 );
1344
1345                 let hex = "450ffcabc6449094918ebe13d4f03e433d20a3d28a768203337bc40b6e4b2c59";
1346                 assert_eq!(onion_keys[1].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1347
1348                 let hex = "05ed2b4a3fb023c2ff5dd6ed4b9b6ea7383f5cfe9d59c11d121ec2c81ca2eea9";
1349                 assert_eq!(onion_keys[1].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1350
1351                 let hex = "3a6b412548762f0dbccce5c7ae7bb8147d1caf9b5471c34120b30bc9c04891cc";
1352                 assert_eq!(
1353                         onion_keys[2].shared_secret.secret_bytes(),
1354                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1355                 );
1356
1357                 let hex = "a1f2dadd184eb1627049673f18c6325814384facdee5bfd935d9cb031a1698a5";
1358                 assert_eq!(onion_keys[2].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
1359
1360                 let hex = "03bfd8225241ea71cd0843db7709f4c222f62ff2d4516fd38b39914ab6b83e0da0";
1361                 assert_eq!(
1362                         onion_keys[2].ephemeral_pubkey.serialize()[..],
1363                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1364                 );
1365
1366                 let hex = "11bf5c4f960239cb37833936aa3d02cea82c0f39fd35f566109c41f9eac8deea";
1367                 assert_eq!(onion_keys[2].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1368
1369                 let hex = "caafe2820fa00eb2eeb78695ae452eba38f5a53ed6d53518c5c6edf76f3f5b78";
1370                 assert_eq!(onion_keys[2].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1371
1372                 let hex = "21e13c2d7cfe7e18836df50872466117a295783ab8aab0e7ecc8c725503ad02d";
1373                 assert_eq!(
1374                         onion_keys[3].shared_secret.secret_bytes(),
1375                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1376                 );
1377
1378                 let hex = "7cfe0b699f35525029ae0fa437c69d0f20f7ed4e3916133f9cacbb13c82ff262";
1379                 assert_eq!(onion_keys[3].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
1380
1381                 let hex = "031dde6926381289671300239ea8e57ffaf9bebd05b9a5b95beaf07af05cd43595";
1382                 assert_eq!(
1383                         onion_keys[3].ephemeral_pubkey.serialize()[..],
1384                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1385                 );
1386
1387                 let hex = "cbe784ab745c13ff5cffc2fbe3e84424aa0fd669b8ead4ee562901a4a4e89e9e";
1388                 assert_eq!(onion_keys[3].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1389
1390                 let hex = "5052aa1b3d9f0655a0932e50d42f0c9ba0705142c25d225515c45f47c0036ee9";
1391                 assert_eq!(onion_keys[3].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1392
1393                 let hex = "b5756b9b542727dbafc6765a49488b023a725d631af688fc031217e90770c328";
1394                 assert_eq!(
1395                         onion_keys[4].shared_secret.secret_bytes(),
1396                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1397                 );
1398
1399                 let hex = "c96e00dddaf57e7edcd4fb5954be5b65b09f17cb6d20651b4e90315be5779205";
1400                 assert_eq!(onion_keys[4].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
1401
1402                 let hex = "03a214ebd875aab6ddfd77f22c5e7311d7f77f17a169e599f157bbcdae8bf071f4";
1403                 assert_eq!(
1404                         onion_keys[4].ephemeral_pubkey.serialize()[..],
1405                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1406                 );
1407
1408                 let hex = "034e18b8cc718e8af6339106e706c52d8df89e2b1f7e9142d996acf88df8799b";
1409                 assert_eq!(onion_keys[4].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1410
1411                 let hex = "8e45e5c61c2b24cb6382444db6698727afb063adecd72aada233d4bf273d975a";
1412                 assert_eq!(onion_keys[4].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1413
1414                 // Packet creation test vectors from BOLT 4 (see
1415                 // https://github.com/lightning/bolts/blob/16973e2b857e853308cafd59e42fa830d75b1642/bolt04/onion-test.json).
1416                 // Note that we represent the test vector payloads 2 and 5 through RawOnionHopData::data
1417                 // with raw hex instead of our in-memory enums, as the payloads contains custom types, and
1418                 // we have no way of representing that with our enums.
1419                 let payloads = vec!(
1420                         RawOnionHopData::new(msgs::OutboundOnionPayload::Forward {
1421                                 short_channel_id: 1,
1422                                 amt_to_forward: 15000,
1423                                 outgoing_cltv_value: 1500,
1424                         }),
1425                         /*
1426                         The second payload is represented by raw hex as it contains custom type data. Content:
1427                         1. length "52" (payload_length 82).
1428
1429                         The first part of the payload has the `NonFinalNode` format, with content as follows:
1430                         2. amt_to_forward "020236b0"
1431                            02 (type amt_to_forward) 02 (length 2) 36b0 (value 14000)
1432                         3. outgoing_cltv_value "04020578"
1433                            04 (type outgoing_cltv_value) 02 (length 2) 0578 (value 1400)
1434                         4. short_channel_id "06080000000000000002"
1435                            06 (type short_channel_id) 08 (length 8) 0000000000000002 (value 2)
1436
1437                         The rest of the payload is custom type data:
1438                         5. custom_record "fd02013c0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f"
1439                         */
1440                         RawOnionHopData {
1441                                 data: <Vec<u8>>::from_hex("52020236b00402057806080000000000000002fd02013c0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f").unwrap(),
1442                         },
1443                         RawOnionHopData::new(msgs::OutboundOnionPayload::Forward {
1444                                 short_channel_id: 3,
1445                                 amt_to_forward: 12500,
1446                                 outgoing_cltv_value: 1250,
1447                         }),
1448                         RawOnionHopData::new(msgs::OutboundOnionPayload::Forward {
1449                                 short_channel_id: 4,
1450                                 amt_to_forward: 10000,
1451                                 outgoing_cltv_value: 1000,
1452                         }),
1453                         /*
1454                         The fifth payload is represented by raw hex as it contains custom type data. Content:
1455                         1. length "fd0110" (payload_length 272).
1456
1457                         The first part of the payload has the `FinalNode` format, with content as follows:
1458                         1. amt_to_forward "02022710"
1459                            02 (type amt_to_forward) 02 (length 2) 2710 (value 10000)
1460                         2. outgoing_cltv_value "040203e8"
1461                            04 (type outgoing_cltv_value) 02 (length 2) 03e8 (value 1000)
1462                         3. payment_data "082224a33562c54507a9334e79f0dc4f17d407e6d7c61f0e2f3d0d38599502f617042710"
1463                            08 (type short_channel_id) 22 (length 34) 24a33562c54507a9334e79f0dc4f17d407e6d7c61f0e2f3d0d38599502f61704 (payment_secret) 2710 (total_msat value 10000)
1464
1465                         The rest of the payload is custom type data:
1466                         4. custom_record "fd012de02a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a"
1467                         */
1468                         RawOnionHopData {
1469                                 data: <Vec<u8>>::from_hex("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").unwrap(),
1470                         },
1471                 );
1472
1473                 // Verify that the serialized OnionHopDataFormat::NonFinalNode tlv payloads matches the test vectors
1474                 let mut w = VecWriter(Vec::new());
1475                 payloads[0].write(&mut w).unwrap();
1476                 let hop_1_serialized_payload = w.0;
1477                 let hex = "1202023a98040205dc06080000000000000001";
1478                 let expected_serialized_hop_1_payload = &<Vec<u8>>::from_hex(hex).unwrap()[..];
1479                 assert_eq!(hop_1_serialized_payload, expected_serialized_hop_1_payload);
1480
1481                 w = VecWriter(Vec::new());
1482                 payloads[2].write(&mut w).unwrap();
1483                 let hop_3_serialized_payload = w.0;
1484                 let hex = "12020230d4040204e206080000000000000003";
1485                 let expected_serialized_hop_3_payload = &<Vec<u8>>::from_hex(hex).unwrap()[..];
1486                 assert_eq!(hop_3_serialized_payload, expected_serialized_hop_3_payload);
1487
1488                 w = VecWriter(Vec::new());
1489                 payloads[3].write(&mut w).unwrap();
1490                 let hop_4_serialized_payload = w.0;
1491                 let hex = "1202022710040203e806080000000000000004";
1492                 let expected_serialized_hop_4_payload = &<Vec<u8>>::from_hex(hex).unwrap()[..];
1493                 assert_eq!(hop_4_serialized_payload, expected_serialized_hop_4_payload);
1494
1495                 let pad_keytype_seed =
1496                         super::gen_pad_from_shared_secret(&get_test_session_key().secret_bytes());
1497
1498                 let packet: msgs::OnionPacket = super::construct_onion_packet_with_writable_hopdata::<_>(
1499                         payloads,
1500                         onion_keys,
1501                         pad_keytype_seed,
1502                         &PaymentHash([0x42; 32]),
1503                 )
1504                 .unwrap();
1505
1506                 let hex = 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
1507                 assert_eq!(packet.encode(), <Vec<u8>>::from_hex(hex).unwrap());
1508         }
1509
1510         #[test]
1511         fn test_failure_packet_onion() {
1512                 // Returning Errors test vectors from BOLT 4
1513
1514                 let onion_keys = build_test_onion_keys();
1515                 let onion_error =
1516                         super::build_failure_packet(onion_keys[4].shared_secret.as_ref(), 0x2002, &[0; 0]);
1517                 let hex = "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";
1518                 assert_eq!(onion_error.encode(), <Vec<u8>>::from_hex(hex).unwrap());
1519
1520                 let onion_packet_1 = super::encrypt_failure_packet(
1521                         onion_keys[4].shared_secret.as_ref(),
1522                         &onion_error.encode()[..],
1523                 );
1524                 let hex = "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";
1525                 assert_eq!(onion_packet_1.data, <Vec<u8>>::from_hex(hex).unwrap());
1526
1527                 let onion_packet_2 = super::encrypt_failure_packet(
1528                         onion_keys[3].shared_secret.as_ref(),
1529                         &onion_packet_1.data[..],
1530                 );
1531                 let hex = "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";
1532                 assert_eq!(onion_packet_2.data, <Vec<u8>>::from_hex(hex).unwrap());
1533
1534                 let onion_packet_3 = super::encrypt_failure_packet(
1535                         onion_keys[2].shared_secret.as_ref(),
1536                         &onion_packet_2.data[..],
1537                 );
1538                 let hex = "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";
1539                 assert_eq!(onion_packet_3.data, <Vec<u8>>::from_hex(hex).unwrap());
1540
1541                 let onion_packet_4 = super::encrypt_failure_packet(
1542                         onion_keys[1].shared_secret.as_ref(),
1543                         &onion_packet_3.data[..],
1544                 );
1545                 let hex = "aac3200c4968f56b21f53e5e374e3a2383ad2b1b6501bbcc45abc31e59b26881b7dfadbb56ec8dae8857add94e6702fb4c3a4de22e2e669e1ed926b04447fc73034bb730f4932acd62727b75348a648a1128744657ca6a4e713b9b646c3ca66cac02cdab44dd3439890ef3aaf61708714f7375349b8da541b2548d452d84de7084bb95b3ac2345201d624d31f4d52078aa0fa05a88b4e20202bd2b86ac5b52919ea305a8949de95e935eed0319cf3cf19ebea61d76ba92532497fcdc9411d06bcd4275094d0a4a3c5d3a945e43305a5a9256e333e1f64dbca5fcd4e03a39b9012d197506e06f29339dfee3331995b21615337ae060233d39befea925cc262873e0530408e6990f1cbd233a150ef7b004ff6166c70c68d9f8c853c1abca640b8660db2921";
1546                 assert_eq!(onion_packet_4.data, <Vec<u8>>::from_hex(hex).unwrap());
1547
1548                 let onion_packet_5 = super::encrypt_failure_packet(
1549                         onion_keys[0].shared_secret.as_ref(),
1550                         &onion_packet_4.data[..],
1551                 );
1552                 let hex = "9c5add3963fc7f6ed7f148623c84134b5647e1306419dbe2174e523fa9e2fbed3a06a19f899145610741c83ad40b7712aefaddec8c6baf7325d92ea4ca4d1df8bce517f7e54554608bf2bd8071a4f52a7a2f7ffbb1413edad81eeea5785aa9d990f2865dc23b4bc3c301a94eec4eabebca66be5cf638f693ec256aec514620cc28ee4a94bd9565bc4d4962b9d3641d4278fb319ed2b84de5b665f307a2db0f7fbb757366067d88c50f7e829138fde4f78d39b5b5802f1b92a8a820865af5cc79f9f30bc3f461c66af95d13e5e1f0381c184572a91dee1c849048a647a1158cf884064deddbf1b0b88dfe2f791428d0ba0f6fb2f04e14081f69165ae66d9297c118f0907705c9c4954a199bae0bb96fad763d690e7daa6cfda59ba7f2c8d11448b604d12d";
1553                 assert_eq!(onion_packet_5.data, <Vec<u8>>::from_hex(hex).unwrap());
1554         }
1555
1556         struct RawOnionHopData {
1557                 data: Vec<u8>,
1558         }
1559         impl RawOnionHopData {
1560                 fn new(orig: msgs::OutboundOnionPayload) -> Self {
1561                         Self { data: orig.encode() }
1562                 }
1563         }
1564         impl Writeable for RawOnionHopData {
1565                 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
1566                         writer.write_all(&self.data[..])
1567                 }
1568         }
1569 }