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

   1 // This file is Copyright its original authors, visible in version control
   2 // history.
   3 //
   4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
   5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
   7 // You may not use this file except in accordance with one or both of these
   8 // licenses.
   9
  10 use crate::crypto::chacha20::ChaCha20;
  11 use crate::crypto::streams::ChaChaReader;
  12 use crate::ln::channelmanager::{HTLCSource, RecipientOnionFields};
  13 use crate::ln::msgs;
  14 use crate::ln::wire::Encode;
  15 use crate::ln::{PaymentHash, PaymentPreimage};
  16 use crate::routing::gossip::NetworkUpdate;
  17 use crate::routing::router::{BlindedTail, Path, RouteHop};
  18 use crate::sign::NodeSigner;
  19 use crate::util::errors::{self, APIError};
  20 use crate::util::logger::Logger;
  21 use crate::util::ser::{LengthCalculatingWriter, Readable, ReadableArgs, Writeable, Writer};
  22
  23 use bitcoin::hashes::cmp::fixed_time_eq;
  24 use bitcoin::hashes::hmac::{Hmac, HmacEngine};
  25 use bitcoin::hashes::sha256::Hash as Sha256;
  26 use bitcoin::hashes::{Hash, HashEngine};
  27
  28 use bitcoin::secp256k1;
  29 use bitcoin::secp256k1::ecdh::SharedSecret;
  30 use bitcoin::secp256k1::{PublicKey, Scalar, Secp256k1, SecretKey};
  31
  32 use crate::io::{Cursor, Read};
  33 use crate::prelude::*;
  34 use core::convert::{AsMut, TryInto};
  35 use core::ops::Deref;
  36
  37 pub(crate) struct OnionKeys {
  38         #[cfg(test)]
  39         pub(crate) shared_secret: SharedSecret,
  40         #[cfg(test)]
  41         pub(crate) blinding_factor: [u8; 32],
  42         pub(crate) ephemeral_pubkey: PublicKey,
  43         pub(crate) rho: [u8; 32],
  44         pub(crate) mu: [u8; 32],
  45 }
  46
  47 #[inline]
  48 pub(crate) fn gen_rho_from_shared_secret(shared_secret: &[u8]) -> [u8; 32] {
  49         assert_eq!(shared_secret.len(), 32);
  50         let mut hmac = HmacEngine::<Sha256>::new(&[0x72, 0x68, 0x6f]); // rho
  51         hmac.input(&shared_secret);
  52         Hmac::from_engine(hmac).to_byte_array()
  53 }
  54
  55 #[inline]
  56 pub(crate) fn gen_rho_mu_from_shared_secret(shared_secret: &[u8]) -> ([u8; 32], [u8; 32]) {
  57         assert_eq!(shared_secret.len(), 32);
  58         let mut engine_rho = HmacEngine::<Sha256>::new(b"rho");
  59         engine_rho.input(&shared_secret);
  60         let hmac_rho = Hmac::from_engine(engine_rho).to_byte_array();
  61
  62         let mut engine_mu = HmacEngine::<Sha256>::new(b"mu");
  63         engine_mu.input(&shared_secret);
  64         let hmac_mu = Hmac::from_engine(engine_mu).to_byte_array();
  65
  66         (hmac_rho, hmac_mu)
  67 }
  68
  69 #[inline]
  70 pub(super) fn gen_um_from_shared_secret(shared_secret: &[u8]) -> [u8; 32] {
  71         assert_eq!(shared_secret.len(), 32);
  72         let mut hmac = HmacEngine::<Sha256>::new(&[0x75, 0x6d]); // um
  73         hmac.input(&shared_secret);
  74         Hmac::from_engine(hmac).to_byte_array()
  75 }
  76
  77 #[inline]
  78 pub(super) fn gen_ammag_from_shared_secret(shared_secret: &[u8]) -> [u8; 32] {
  79         assert_eq!(shared_secret.len(), 32);
  80         let mut hmac = HmacEngine::<Sha256>::new(&[0x61, 0x6d, 0x6d, 0x61, 0x67]); // ammag
  81         hmac.input(&shared_secret);
  82         Hmac::from_engine(hmac).to_byte_array()
  83 }
  84
  85 #[cfg(test)]
  86 #[inline]
  87 pub(super) fn gen_pad_from_shared_secret(shared_secret: &[u8]) -> [u8; 32] {
  88         assert_eq!(shared_secret.len(), 32);
  89         let mut hmac = HmacEngine::<Sha256>::new(&[0x70, 0x61, 0x64]); // pad
  90         hmac.input(&shared_secret);
  91         Hmac::from_engine(hmac).to_byte_array()
  92 }
  93
  94 /// Calculates a pubkey for the next hop, such as the next hop's packet pubkey or blinding point.
  95 pub(crate) fn next_hop_pubkey<T: secp256k1::Verification>(
  96         secp_ctx: &Secp256k1<T>, curr_pubkey: PublicKey, shared_secret: &[u8],
  97 ) -> Result<PublicKey, secp256k1::Error> {
  98         let blinding_factor = {
  99                 let mut sha = Sha256::engine();
 100                 sha.input(&curr_pubkey.serialize()[..]);
 101                 sha.input(shared_secret);
 102                 Sha256::from_engine(sha).to_byte_array()
 103         };
 104
 105         curr_pubkey.mul_tweak(secp_ctx, &Scalar::from_be_bytes(blinding_factor).unwrap())
 106 }
 107
 108 // can only fail if an intermediary hop has an invalid public key or session_priv is invalid
 109 #[inline]
 110 pub(super) fn construct_onion_keys_callback<T, FType>(
 111         secp_ctx: &Secp256k1<T>, path: &Path, session_priv: &SecretKey, mut callback: FType,
 112 ) -> Result<(), secp256k1::Error>
 113 where
 114         T: secp256k1::Signing,
 115         FType: FnMut(SharedSecret, [u8; 32], PublicKey, Option<&RouteHop>, usize),
 116 {
 117         let mut blinded_priv = session_priv.clone();
 118         let mut blinded_pub = PublicKey::from_secret_key(secp_ctx, &blinded_priv);
 119
 120         let unblinded_hops_iter = path.hops.iter().map(|h| (&h.pubkey, Some(h)));
 121         let blinded_pks_iter = path
 122                 .blinded_tail
 123                 .as_ref()
 124                 .map(|t| t.hops.iter())
 125                 .unwrap_or([].iter())
 126                 .skip(1) // Skip the intro node because it's included in the unblinded hops
 127                 .map(|h| (&h.blinded_node_id, None));
 128         for (idx, (pubkey, route_hop_opt)) in unblinded_hops_iter.chain(blinded_pks_iter).enumerate() {
 129                 let shared_secret = SharedSecret::new(pubkey, &blinded_priv);
 130
 131                 let mut sha = Sha256::engine();
 132                 sha.input(&blinded_pub.serialize()[..]);
 133                 sha.input(shared_secret.as_ref());
 134                 let blinding_factor = Sha256::from_engine(sha).to_byte_array();
 135
 136                 let ephemeral_pubkey = blinded_pub;
 137
 138                 blinded_priv = blinded_priv.mul_tweak(&Scalar::from_be_bytes(blinding_factor).unwrap())?;
 139                 blinded_pub = PublicKey::from_secret_key(secp_ctx, &blinded_priv);
 140
 141                 callback(shared_secret, blinding_factor, ephemeral_pubkey, route_hop_opt, idx);
 142         }
 143
 144         Ok(())
 145 }
 146
 147 // can only fail if an intermediary hop has an invalid public key or session_priv is invalid
 148 pub(super) fn construct_onion_keys<T: secp256k1::Signing>(
 149         secp_ctx: &Secp256k1<T>, path: &Path, session_priv: &SecretKey,
 150 ) -> Result<Vec<OnionKeys>, secp256k1::Error> {
 151         let mut res = Vec::with_capacity(path.hops.len());
 152
 153         construct_onion_keys_callback(
 154                 secp_ctx,
 155                 &path,
 156                 session_priv,
 157                 |shared_secret, _blinding_factor, ephemeral_pubkey, _, _| {
 158                         let (rho, mu) = gen_rho_mu_from_shared_secret(shared_secret.as_ref());
 159
 160                         res.push(OnionKeys {
 161                                 #[cfg(test)]
 162                                 shared_secret,
 163                                 #[cfg(test)]
 164                                 blinding_factor: _blinding_factor,
 165                                 ephemeral_pubkey,
 166                                 rho,
 167                                 mu,
 168                         });
 169                 },
 170         )?;
 171
 172         Ok(res)
 173 }
 174
 175 /// returns the hop data, as well as the first-hop value_msat and CLTV value we should send.
 176 pub(super) fn build_onion_payloads(
 177         path: &Path, total_msat: u64, mut recipient_onion: RecipientOnionFields,
 178         starting_htlc_offset: u32, keysend_preimage: &Option<PaymentPreimage>,
 179 ) -> Result<(Vec<msgs::OutboundOnionPayload>, u64, u32), APIError> {
 180         let mut cur_value_msat = 0u64;
 181         let mut cur_cltv = starting_htlc_offset;
 182         let mut last_short_channel_id = 0;
 183         let mut res: Vec<msgs::OutboundOnionPayload> = Vec::with_capacity(
 184                 path.hops.len() + path.blinded_tail.as_ref().map_or(0, |t| t.hops.len()),
 185         );
 186
 187         for (idx, hop) in path.hops.iter().rev().enumerate() {
 188                 // First hop gets special values so that it can check, on receipt, that everything is
 189                 // exactly as it should be (and the next hop isn't trying to probe to find out if we're
 190                 // the intended recipient).
 191                 let value_msat = if cur_value_msat == 0 { hop.fee_msat } else { cur_value_msat };
 192                 let cltv = if cur_cltv == starting_htlc_offset {
 193                         hop.cltv_expiry_delta + starting_htlc_offset
 194                 } else {
 195                         cur_cltv
 196                 };
 197                 if idx == 0 {
 198                         if let Some(BlindedTail {
 199                                 blinding_point,
 200                                 hops,
 201                                 final_value_msat,
 202                                 excess_final_cltv_expiry_delta,
 203                                 ..
 204                         }) = &path.blinded_tail
 205                         {
 206                                 let mut blinding_point = Some(*blinding_point);
 207                                 for (i, blinded_hop) in hops.iter().enumerate() {
 208                                         if i == hops.len() - 1 {
 209                                                 cur_value_msat += final_value_msat;
 210                                                 res.push(msgs::OutboundOnionPayload::BlindedReceive {
 211                                                         sender_intended_htlc_amt_msat: *final_value_msat,
 212                                                         total_msat,
 213                                                         cltv_expiry_height: cur_cltv + excess_final_cltv_expiry_delta,
 214                                                         encrypted_tlvs: blinded_hop.encrypted_payload.clone(),
 215                                                         intro_node_blinding_point: blinding_point.take(),
 216                                                         keysend_preimage: *keysend_preimage,
 217                                                 });
 218                                         } else {
 219                                                 res.push(msgs::OutboundOnionPayload::BlindedForward {
 220                                                         encrypted_tlvs: blinded_hop.encrypted_payload.clone(),
 221                                                         intro_node_blinding_point: blinding_point.take(),
 222                                                 });
 223                                         }
 224                                 }
 225                         } else {
 226                                 res.push(msgs::OutboundOnionPayload::Receive {
 227                                         payment_data: if let Some(secret) = recipient_onion.payment_secret.take() {
 228                                                 Some(msgs::FinalOnionHopData { payment_secret: secret, total_msat })
 229                                         } else {
 230                                                 None
 231                                         },
 232                                         payment_metadata: recipient_onion.payment_metadata.take(),
 233                                         keysend_preimage: *keysend_preimage,
 234                                         custom_tlvs: recipient_onion.custom_tlvs.clone(),
 235                                         sender_intended_htlc_amt_msat: value_msat,
 236                                         cltv_expiry_height: cltv,
 237                                 });
 238                         }
 239                 } else {
 240                         let payload = msgs::OutboundOnionPayload::Forward {
 241                                 short_channel_id: last_short_channel_id,
 242                                 amt_to_forward: value_msat,
 243                                 outgoing_cltv_value: cltv,
 244                         };
 245                         res.insert(0, payload);
 246                 }
 247                 cur_value_msat += hop.fee_msat;
 248                 if cur_value_msat >= 21000000 * 100000000 * 1000 {
 249                         return Err(APIError::InvalidRoute { err: "Channel fees overflowed?".to_owned() });
 250                 }
 251                 cur_cltv += hop.cltv_expiry_delta as u32;
 252                 if cur_cltv >= 500000000 {
 253                         return Err(APIError::InvalidRoute { err: "Channel CLTV overflowed?".to_owned() });
 254                 }
 255                 last_short_channel_id = hop.short_channel_id;
 256         }
 257         Ok((res, cur_value_msat, cur_cltv))
 258 }
 259
 260 /// Length of the onion data packet. Before TLV-based onions this was 20 65-byte hops, though now
 261 /// the hops can be of variable length.
 262 pub(crate) const ONION_DATA_LEN: usize = 20 * 65;
 263
 264 pub(super) const INVALID_ONION_BLINDING: u16 = 0x8000 | 0x4000 | 24;
 265
 266 #[inline]
 267 fn shift_slice_right(arr: &mut [u8], amt: usize) {
 268         for i in (amt..arr.len()).rev() {
 269                 arr[i] = arr[i - amt];
 270         }
 271         for i in 0..amt {
 272                 arr[i] = 0;
 273         }
 274 }
 275
 276 pub(super) fn construct_onion_packet(
 277         payloads: Vec<msgs::OutboundOnionPayload>, onion_keys: Vec<OnionKeys>, prng_seed: [u8; 32],
 278         associated_data: &PaymentHash,
 279 ) -> Result<msgs::OnionPacket, ()> {
 280         let mut packet_data = [0; ONION_DATA_LEN];
 281
 282         let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
 283         chacha.process(&[0; ONION_DATA_LEN], &mut packet_data);
 284
 285         let packet = FixedSizeOnionPacket(packet_data);
 286         construct_onion_packet_with_init_noise::<_, _>(
 287                 payloads,
 288                 onion_keys,
 289                 packet,
 290                 Some(associated_data),
 291         )
 292 }
 293
 294 #[allow(unused)]
 295 pub(super) fn construct_trampoline_onion_packet(
 296         payloads: Vec<msgs::OutboundTrampolinePayload>, onion_keys: Vec<OnionKeys>,
 297         prng_seed: [u8; 32], associated_data: &PaymentHash, length: u16,
 298 ) -> Result<msgs::TrampolineOnionPacket, ()> {
 299         let mut packet_data = vec![0u8; length as usize];
 300
 301         let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
 302         chacha.process(&vec![0u8; length as usize], &mut packet_data);
 303
 304         construct_onion_packet_with_init_noise::<_, _>(
 305                 payloads,
 306                 onion_keys,
 307                 packet_data,
 308                 Some(associated_data),
 309         )
 310 }
 311
 312 #[cfg(test)]
 313 /// Used in testing to write bogus `BogusOnionHopData` as well as `RawOnionHopData`, which is
 314 /// otherwise not representable in `msgs::OnionHopData`.
 315 pub(super) fn construct_onion_packet_with_writable_hopdata<HD: Writeable>(
 316         payloads: Vec<HD>, onion_keys: Vec<OnionKeys>, prng_seed: [u8; 32],
 317         associated_data: &PaymentHash,
 318 ) -> Result<msgs::OnionPacket, ()> {
 319         let mut packet_data = [0; ONION_DATA_LEN];
 320
 321         let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
 322         chacha.process(&[0; ONION_DATA_LEN], &mut packet_data);
 323
 324         let packet = FixedSizeOnionPacket(packet_data);
 325         construct_onion_packet_with_init_noise::<_, _>(
 326                 payloads,
 327                 onion_keys,
 328                 packet,
 329                 Some(associated_data),
 330         )
 331 }
 332
 333 /// Since onion message packets and onion payment packets have different lengths but are otherwise
 334 /// identical, we use this trait to allow `construct_onion_packet_with_init_noise` to return either
 335 /// type.
 336 pub(crate) trait Packet {
 337         type Data: AsMut<[u8]>;
 338         fn new(pubkey: PublicKey, hop_data: Self::Data, hmac: [u8; 32]) -> Self;
 339 }
 340
 341 // Needed for rustc versions older than 1.47 to avoid E0277: "arrays only have std trait
 342 // implementations for lengths 0..=32".
 343 pub(crate) struct FixedSizeOnionPacket(pub(crate) [u8; ONION_DATA_LEN]);
 344
 345 impl AsMut<[u8]> for FixedSizeOnionPacket {
 346         fn as_mut(&mut self) -> &mut [u8] {
 347                 &mut self.0
 348         }
 349 }
 350
 351 pub(crate) fn payloads_serialized_length<HD: Writeable>(payloads: &Vec<HD>) -> usize {
 352         payloads.iter().map(|p| p.serialized_length() + 32 /* HMAC */).sum()
 353 }
 354
 355 pub(crate) fn construct_onion_message_packet<HD: Writeable, P: Packet<Data = Vec<u8>>>(
 356         payloads: Vec<HD>, onion_keys: Vec<OnionKeys>, prng_seed: [u8; 32], packet_data_len: usize,
 357 ) -> Result<P, ()> {
 358         let mut packet_data = vec![0; packet_data_len];
 359
 360         let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
 361         chacha.process_in_place(&mut packet_data);
 362
 363         construct_onion_packet_with_init_noise::<_, _>(payloads, onion_keys, packet_data, None)
 364 }
 365
 366 fn construct_onion_packet_with_init_noise<HD: Writeable, P: Packet>(
 367         mut payloads: Vec<HD>, onion_keys: Vec<OnionKeys>, mut packet_data: P::Data,
 368         associated_data: Option<&PaymentHash>,
 369 ) -> Result<P, ()> {
 370         let filler = {
 371                 let packet_data = packet_data.as_mut();
 372                 const ONION_HOP_DATA_LEN: usize = 65; // We may decrease this eventually after TLV is common
 373                 let mut res = Vec::with_capacity(ONION_HOP_DATA_LEN * (payloads.len() - 1));
 374
 375                 let mut pos = 0;
 376                 for (i, (payload, keys)) in payloads.iter().zip(onion_keys.iter()).enumerate() {
 377                         let mut chacha = ChaCha20::new(&keys.rho, &[0u8; 8]);
 378                         // TODO: Batch this.
 379                         for _ in 0..(packet_data.len() - pos) {
 380                                 let mut dummy = [0; 1];
 381                                 chacha.process_in_place(&mut dummy); // We don't have a seek function :(
 382                         }
 383
 384                         let mut payload_len = LengthCalculatingWriter(0);
 385                         payload.write(&mut payload_len).expect("Failed to calculate length");
 386                         pos += payload_len.0 + 32;
 387                         if pos > packet_data.len() {
 388                                 return Err(());
 389                         }
 390
 391                         if i == payloads.len() - 1 {
 392                                 break;
 393                         }
 394
 395                         res.resize(pos, 0u8);
 396                         chacha.process_in_place(&mut res);
 397                 }
 398                 res
 399         };
 400
 401         let mut hmac_res = [0; 32];
 402         for (i, (payload, keys)) in payloads.iter_mut().zip(onion_keys.iter()).rev().enumerate() {
 403                 let mut payload_len = LengthCalculatingWriter(0);
 404                 payload.write(&mut payload_len).expect("Failed to calculate length");
 405
 406                 let packet_data = packet_data.as_mut();
 407                 shift_slice_right(packet_data, payload_len.0 + 32);
 408                 packet_data[0..payload_len.0].copy_from_slice(&payload.encode()[..]);
 409                 packet_data[payload_len.0..(payload_len.0 + 32)].copy_from_slice(&hmac_res);
 410
 411                 let mut chacha = ChaCha20::new(&keys.rho, &[0u8; 8]);
 412                 chacha.process_in_place(packet_data);
 413
 414                 if i == 0 {
 415                         let stop_index = packet_data.len();
 416                         let start_index = stop_index.checked_sub(filler.len()).ok_or(())?;
 417                         packet_data[start_index..stop_index].copy_from_slice(&filler[..]);
 418                 }
 419
 420                 let mut hmac = HmacEngine::<Sha256>::new(&keys.mu);
 421                 hmac.input(packet_data);
 422                 if let Some(associated_data) = associated_data {
 423                         hmac.input(&associated_data.0[..]);
 424                 }
 425                 hmac_res = Hmac::from_engine(hmac).to_byte_array();
 426         }
 427
 428         Ok(P::new(onion_keys.first().unwrap().ephemeral_pubkey, packet_data, hmac_res))
 429 }
 430
 431 /// Encrypts a failure packet. raw_packet can either be a
 432 /// msgs::DecodedOnionErrorPacket.encode() result or a msgs::OnionErrorPacket.data element.
 433 pub(super) fn encrypt_failure_packet(
 434         shared_secret: &[u8], raw_packet: &[u8],
 435 ) -> msgs::OnionErrorPacket {
 436         let ammag = gen_ammag_from_shared_secret(&shared_secret);
 437
 438         let mut packet_crypted = Vec::with_capacity(raw_packet.len());
 439         packet_crypted.resize(raw_packet.len(), 0);
 440         let mut chacha = ChaCha20::new(&ammag, &[0u8; 8]);
 441         chacha.process(&raw_packet, &mut packet_crypted[..]);
 442         msgs::OnionErrorPacket { data: packet_crypted }
 443 }
 444
 445 pub(super) fn build_failure_packet(
 446         shared_secret: &[u8], failure_type: u16, failure_data: &[u8],
 447 ) -> msgs::DecodedOnionErrorPacket {
 448         assert_eq!(shared_secret.len(), 32);
 449         assert!(failure_data.len() <= 256 - 2);
 450
 451         let um = gen_um_from_shared_secret(&shared_secret);
 452
 453         let failuremsg = {
 454                 let mut res = Vec::with_capacity(2 + failure_data.len());
 455                 res.push(((failure_type >> 8) & 0xff) as u8);
 456                 res.push(((failure_type >> 0) & 0xff) as u8);
 457                 res.extend_from_slice(&failure_data[..]);
 458                 res
 459         };
 460         let pad = {
 461                 let mut res = Vec::with_capacity(256 - 2 - failure_data.len());
 462                 res.resize(256 - 2 - failure_data.len(), 0);
 463                 res
 464         };
 465         let mut packet = msgs::DecodedOnionErrorPacket { hmac: [0; 32], failuremsg, pad };
 466
 467         let mut hmac = HmacEngine::<Sha256>::new(&um);
 468         hmac.input(&packet.encode()[32..]);
 469         packet.hmac = Hmac::from_engine(hmac).to_byte_array();
 470
 471         packet
 472 }
 473
 474 #[cfg(test)]
 475 pub(super) fn build_first_hop_failure_packet(
 476         shared_secret: &[u8], failure_type: u16, failure_data: &[u8],
 477 ) -> msgs::OnionErrorPacket {
 478         let failure_packet = build_failure_packet(shared_secret, failure_type, failure_data);
 479         encrypt_failure_packet(shared_secret, &failure_packet.encode()[..])
 480 }
 481
 482 pub(crate) struct DecodedOnionFailure {
 483         pub(crate) network_update: Option<NetworkUpdate>,
 484         pub(crate) short_channel_id: Option<u64>,
 485         pub(crate) payment_failed_permanently: bool,
 486         pub(crate) failed_within_blinded_path: bool,
 487         #[cfg(test)]
 488         pub(crate) onion_error_code: Option<u16>,
 489         #[cfg(test)]
 490         pub(crate) onion_error_data: Option<Vec<u8>>,
 491 }
 492
 493 /// Note that we always decrypt `packet` in-place here even if the deserialization into
 494 /// [`msgs::DecodedOnionErrorPacket`] ultimately fails.
 495 fn decrypt_onion_error_packet(
 496         packet: &mut Vec<u8>, shared_secret: SharedSecret,
 497 ) -> Result<msgs::DecodedOnionErrorPacket, msgs::DecodeError> {
 498         let ammag = gen_ammag_from_shared_secret(shared_secret.as_ref());
 499         let mut chacha = ChaCha20::new(&ammag, &[0u8; 8]);
 500         chacha.process_in_place(packet);
 501         msgs::DecodedOnionErrorPacket::read(&mut Cursor::new(packet))
 502 }
 503
 504 /// Process failure we got back from upstream on a payment we sent (implying htlc_source is an
 505 /// OutboundRoute).
 506 #[inline]
 507 pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
 508         secp_ctx: &Secp256k1<T>, logger: &L, htlc_source: &HTLCSource, mut encrypted_packet: Vec<u8>,
 509 ) -> DecodedOnionFailure
 510 where
 511         L::Target: Logger,
 512 {
 513         let (path, session_priv, first_hop_htlc_msat) = match htlc_source {
 514                 HTLCSource::OutboundRoute {
 515                         ref path, ref session_priv, ref first_hop_htlc_msat, ..
 516                 } => (path, session_priv, first_hop_htlc_msat),
 517                 _ => {
 518                         unreachable!()
 519                 },
 520         };
 521
 522         // Learnings from the HTLC failure to inform future payment retries and scoring.
 523         struct FailureLearnings {
 524                 network_update: Option<NetworkUpdate>,
 525                 short_channel_id: Option<u64>,
 526                 payment_failed_permanently: bool,
 527                 failed_within_blinded_path: bool,
 528         }
 529         let mut res: Option<FailureLearnings> = None;
 530         let mut htlc_msat = *first_hop_htlc_msat;
 531         let mut error_code_ret = None;
 532         let mut error_packet_ret = None;
 533         let mut is_from_final_node = false;
 534
 535         const BADONION: u16 = 0x8000;
 536         const PERM: u16 = 0x4000;
 537         const NODE: u16 = 0x2000;
 538         const UPDATE: u16 = 0x1000;
 539
 540         // Handle packed channel/node updates for passing back for the route handler
 541         let callback = |shared_secret, _, _, route_hop_opt: Option<&RouteHop>, route_hop_idx| {
 542                 if res.is_some() {
 543                         return;
 544                 }
 545
 546                 let route_hop = match route_hop_opt {
 547                         Some(hop) => hop,
 548                         None => {
 549                                 // Got an error from within a blinded route.
 550                                 error_code_ret = Some(BADONION | PERM | 24); // invalid_onion_blinding
 551                                 error_packet_ret = Some(vec![0; 32]);
 552                                 res = Some(FailureLearnings {
 553                                         network_update: None,
 554                                         short_channel_id: None,
 555                                         payment_failed_permanently: false,
 556                                         failed_within_blinded_path: true,
 557                                 });
 558                                 return;
 559                         },
 560                 };
 561
 562                 // The failing hop includes either the inbound channel to the recipient or the outbound channel
 563                 // from the current hop (i.e., the next hop's inbound channel).
 564                 let num_blinded_hops = path.blinded_tail.as_ref().map_or(0, |bt| bt.hops.len());
 565                 // For 1-hop blinded paths, the final `path.hops` entry is the recipient.
 566                 is_from_final_node = route_hop_idx + 1 == path.hops.len() && num_blinded_hops <= 1;
 567                 let failing_route_hop = if is_from_final_node {
 568                         route_hop
 569                 } else {
 570                         match path.hops.get(route_hop_idx + 1) {
 571                                 Some(hop) => hop,
 572                                 None => {
 573                                         // The failing hop is within a multi-hop blinded path.
 574                                         #[cfg(not(test))]
 575                                         {
 576                                                 error_code_ret = Some(BADONION | PERM | 24); // invalid_onion_blinding
 577                                                 error_packet_ret = Some(vec![0; 32]);
 578                                         }
 579                                         #[cfg(test)]
 580                                         {
 581                                                 // Actually parse the onion error data in tests so we can check that blinded hops fail
 582                                                 // back correctly.
 583                                                 let err_packet =
 584                                                         decrypt_onion_error_packet(&mut encrypted_packet, shared_secret)
 585                                                                 .unwrap();
 586                                                 error_code_ret = Some(u16::from_be_bytes(
 587                                                         err_packet.failuremsg.get(0..2).unwrap().try_into().unwrap(),
 588                                                 ));
 589                                                 error_packet_ret = Some(err_packet.failuremsg[2..].to_vec());
 590                                         }
 591
 592                                         res = Some(FailureLearnings {
 593                                                 network_update: None,
 594                                                 short_channel_id: None,
 595                                                 payment_failed_permanently: false,
 596                                                 failed_within_blinded_path: true,
 597                                         });
 598                                         return;
 599                                 },
 600                         }
 601                 };
 602
 603                 let amt_to_forward = htlc_msat - route_hop.fee_msat;
 604                 htlc_msat = amt_to_forward;
 605
 606                 let err_packet = match decrypt_onion_error_packet(&mut encrypted_packet, shared_secret) {
 607                         Ok(p) => p,
 608                         Err(_) => return,
 609                 };
 610                 let um = gen_um_from_shared_secret(shared_secret.as_ref());
 611                 let mut hmac = HmacEngine::<Sha256>::new(&um);
 612                 hmac.input(&err_packet.encode()[32..]);
 613
 614                 if !fixed_time_eq(&Hmac::from_engine(hmac).to_byte_array(), &err_packet.hmac) {
 615                         return;
 616                 }
 617                 let error_code_slice = match err_packet.failuremsg.get(0..2) {
 618                         Some(s) => s,
 619                         None => {
 620                                 // Useless packet that we can't use but it passed HMAC, so it definitely came from the peer
 621                                 // in question
 622                                 let network_update = Some(NetworkUpdate::NodeFailure {
 623                                         node_id: route_hop.pubkey,
 624                                         is_permanent: true,
 625                                 });
 626                                 let short_channel_id = Some(route_hop.short_channel_id);
 627                                 res = Some(FailureLearnings {
 628                                         network_update,
 629                                         short_channel_id,
 630                                         payment_failed_permanently: is_from_final_node,
 631                                         failed_within_blinded_path: false,
 632                                 });
 633                                 return;
 634                         },
 635                 };
 636
 637                 let error_code = u16::from_be_bytes(error_code_slice.try_into().expect("len is 2"));
 638                 error_code_ret = Some(error_code);
 639                 error_packet_ret = Some(err_packet.failuremsg[2..].to_vec());
 640
 641                 let (debug_field, debug_field_size) = errors::get_onion_debug_field(error_code);
 642
 643                 // indicate that payment parameter has failed and no need to update Route object
 644                 let payment_failed = match error_code & 0xff {
 645                         15 | 16 | 17 | 18 | 19 | 23 => true,
 646                         _ => false,
 647                 } && is_from_final_node; // PERM bit observed below even if this error is from the intermediate nodes
 648
 649                 let mut network_update = None;
 650                 let mut short_channel_id = None;
 651
 652                 if error_code & BADONION == BADONION {
 653                         // If the error code has the BADONION bit set, always blame the channel from the node
 654                         // "originating" the error to its next hop. The "originator" is ultimately actually claiming
 655                         // that its counterparty is the one who is failing the HTLC.
 656                         // If the "originator" here isn't lying we should really mark the next-hop node as failed
 657                         // entirely, but we can't be confident in that, as it would allow any node to get us to
 658                         // completely ban one of its counterparties. Instead, we simply remove the channel in
 659                         // question.
 660                         network_update = Some(NetworkUpdate::ChannelFailure {
 661                                 short_channel_id: failing_route_hop.short_channel_id,
 662                                 is_permanent: true,
 663                         });
 664                 } else if error_code & NODE == NODE {
 665                         let is_permanent = error_code & PERM == PERM;
 666                         network_update =
 667                                 Some(NetworkUpdate::NodeFailure { node_id: route_hop.pubkey, is_permanent });
 668                         short_channel_id = Some(route_hop.short_channel_id);
 669                 } else if error_code & PERM == PERM {
 670                         if !payment_failed {
 671                                 network_update = Some(NetworkUpdate::ChannelFailure {
 672                                         short_channel_id: failing_route_hop.short_channel_id,
 673                                         is_permanent: true,
 674                                 });
 675                                 short_channel_id = Some(failing_route_hop.short_channel_id);
 676                         }
 677                 } else if error_code & UPDATE == UPDATE {
 678                         if let Some(update_len_slice) =
 679                                 err_packet.failuremsg.get(debug_field_size + 2..debug_field_size + 4)
 680                         {
 681                                 let update_len =
 682                                         u16::from_be_bytes(update_len_slice.try_into().expect("len is 2")) as usize;
 683                                 if let Some(mut update_slice) = err_packet
 684                                         .failuremsg
 685                                         .get(debug_field_size + 4..debug_field_size + 4 + update_len)
 686                                 {
 687                                         // Historically, the BOLTs were unclear if the message type
 688                                         // bytes should be included here or not. The BOLTs have now
 689                                         // been updated to indicate that they *are* included, but many
 690                                         // nodes still send messages without the type bytes, so we
 691                                         // support both here.
 692                                         // TODO: Switch to hard require the type prefix, as the current
 693                                         // permissiveness introduces the (although small) possibility
 694                                         // that we fail to decode legitimate channel updates that
 695                                         // happen to start with ChannelUpdate::TYPE, i.e., [0x01, 0x02].
 696                                         if update_slice.len() > 2
 697                                                 && update_slice[0..2] == msgs::ChannelUpdate::TYPE.to_be_bytes()
 698                                         {
 699                                                 update_slice = &update_slice[2..];
 700                                         } else {
 701                                                 log_trace!(logger, "Failure provided features a channel update without type prefix. Deprecated, but allowing for now.");
 702                                         }
 703                                         let update_opt = msgs::ChannelUpdate::read(&mut Cursor::new(&update_slice));
 704                                         if update_opt.is_ok() || update_slice.is_empty() {
 705                                                 // if channel_update should NOT have caused the failure:
 706                                                 // MAY treat the channel_update as invalid.
 707                                                 let is_chan_update_invalid = match error_code & 0xff {
 708                                                         7 => false,
 709                                                         11 => {
 710                                                                 update_opt.is_ok()
 711                                                                         && amt_to_forward
 712                                                                                 > update_opt.as_ref().unwrap().contents.htlc_minimum_msat
 713                                                         },
 714                                                         12 => {
 715                                                                 update_opt.is_ok()
 716                                                                         && amt_to_forward
 717                                                                                 .checked_mul(
 718                                                                                         update_opt
 719                                                                                                 .as_ref()
 720                                                                                                 .unwrap()
 721                                                                                                 .contents
 722                                                                                                 .fee_proportional_millionths as u64,
 723                                                                                 )
 724                                                                                 .map(|prop_fee| prop_fee / 1_000_000)
 725                                                                                 .and_then(|prop_fee| {
 726                                                                                         prop_fee.checked_add(
 727                                                                                                 update_opt.as_ref().unwrap().contents.fee_base_msat
 728                                                                                                         as u64,
 729                                                                                         )
 730                                                                                 })
 731                                                                                 .map(|fee_msats| route_hop.fee_msat >= fee_msats)
 732                                                                                 .unwrap_or(false)
 733                                                         },
 734                                                         13 => {
 735                                                                 update_opt.is_ok()
 736                                                                         && route_hop.cltv_expiry_delta as u16
 737                                                                                 >= update_opt.as_ref().unwrap().contents.cltv_expiry_delta
 738                                                         },
 739                                                         14 => false, // expiry_too_soon; always valid?
 740                                                         20 => update_opt.as_ref().unwrap().contents.flags & 2 == 0,
 741                                                         _ => false, // unknown error code; take channel_update as valid
 742                                                 };
 743                                                 if is_chan_update_invalid {
 744                                                         // This probably indicates the node which forwarded
 745                                                         // to the node in question corrupted something.
 746                                                         network_update = Some(NetworkUpdate::ChannelFailure {
 747                                                                 short_channel_id: route_hop.short_channel_id,
 748                                                                 is_permanent: true,
 749                                                         });
 750                                                 } else {
 751                                                         if let Ok(chan_update) = update_opt {
 752                                                                 // Make sure the ChannelUpdate contains the expected
 753                                                                 // short channel id.
 754                                                                 if failing_route_hop.short_channel_id
 755                                                                         == chan_update.contents.short_channel_id
 756                                                                 {
 757                                                                         short_channel_id = Some(failing_route_hop.short_channel_id);
 758                                                                 } else {
 759                                                                         log_info!(logger, "Node provided a channel_update for which it was not authoritative, ignoring.");
 760                                                                 }
 761                                                                 network_update =
 762                                                                         Some(NetworkUpdate::ChannelUpdateMessage { msg: chan_update })
 763                                                         } else {
 764                                                                 // The node in question intentionally encoded a 0-length channel update. This is
 765                                                                 // likely due to https://github.com/ElementsProject/lightning/issues/6200.
 766                                                                 short_channel_id = Some(failing_route_hop.short_channel_id);
 767                                                                 network_update = Some(NetworkUpdate::ChannelFailure {
 768                                                                         short_channel_id: failing_route_hop.short_channel_id,
 769                                                                         is_permanent: false,
 770                                                                 });
 771                                                         }
 772                                                 };
 773                                         } else {
 774                                                 // If the channel_update had a non-zero length (i.e. was
 775                                                 // present) but we couldn't read it, treat it as a total
 776                                                 // node failure.
 777                                                 log_info!(
 778                                                         logger,
 779                                                         "Failed to read a channel_update of len {} in an onion",
 780                                                         update_slice.len()
 781                                                 );
 782                                         }
 783                                 }
 784                         }
 785                         if network_update.is_none() {
 786                                 // They provided an UPDATE which was obviously bogus, not worth
 787                                 // trying to relay through them anymore.
 788                                 network_update = Some(NetworkUpdate::NodeFailure {
 789                                         node_id: route_hop.pubkey,
 790                                         is_permanent: true,
 791                                 });
 792                         }
 793                         if short_channel_id.is_none() {
 794                                 short_channel_id = Some(route_hop.short_channel_id);
 795                         }
 796                 } else if payment_failed {
 797                         // Only blame the hop when a value in the HTLC doesn't match the corresponding value in the
 798                         // onion.
 799                         short_channel_id = match error_code & 0xff {
 800                                 18 | 19 => Some(route_hop.short_channel_id),
 801                                 _ => None,
 802                         };
 803                 } else {
 804                         // We can't understand their error messages and they failed to forward...they probably can't
 805                         // understand our forwards so it's really not worth trying any further.
 806                         network_update =
 807                                 Some(NetworkUpdate::NodeFailure { node_id: route_hop.pubkey, is_permanent: true });
 808                         short_channel_id = Some(route_hop.short_channel_id);
 809                 }
 810
 811                 res = Some(FailureLearnings {
 812                         network_update,
 813                         short_channel_id,
 814                         payment_failed_permanently: error_code & PERM == PERM && is_from_final_node,
 815                         failed_within_blinded_path: false,
 816                 });
 817
 818                 let (description, title) = errors::get_onion_error_description(error_code);
 819                 if debug_field_size > 0 && err_packet.failuremsg.len() >= 4 + debug_field_size {
 820                         log_info!(
 821                                 logger,
 822                                 "Onion Error[from {}: {}({:#x}) {}({})] {}",
 823                                 route_hop.pubkey,
 824                                 title,
 825                                 error_code,
 826                                 debug_field,
 827                                 log_bytes!(&err_packet.failuremsg[4..4 + debug_field_size]),
 828                                 description
 829                         );
 830                 } else {
 831                         log_info!(
 832                                 logger,
 833                                 "Onion Error[from {}: {}({:#x})] {}",
 834                                 route_hop.pubkey,
 835                                 title,
 836                                 error_code,
 837                                 description
 838                         );
 839                 }
 840         };
 841
 842         construct_onion_keys_callback(secp_ctx, &path, session_priv, callback)
 843                 .expect("Route that we sent via spontaneously grew invalid keys in the middle of it?");
 844
 845         if let Some(FailureLearnings {
 846                 network_update,
 847                 short_channel_id,
 848                 payment_failed_permanently,
 849                 failed_within_blinded_path,
 850         }) = res
 851         {
 852                 DecodedOnionFailure {
 853                         network_update,
 854                         short_channel_id,
 855                         payment_failed_permanently,
 856                         failed_within_blinded_path,
 857                         #[cfg(test)]
 858                         onion_error_code: error_code_ret,
 859                         #[cfg(test)]
 860                         onion_error_data: error_packet_ret,
 861                 }
 862         } else {
 863                 // only not set either packet unparseable or hmac does not match with any
 864                 // payment not retryable only when garbage is from the final node
 865                 DecodedOnionFailure {
 866                         network_update: None,
 867                         short_channel_id: None,
 868                         payment_failed_permanently: is_from_final_node,
 869                         failed_within_blinded_path: false,
 870                         #[cfg(test)]
 871                         onion_error_code: None,
 872                         #[cfg(test)]
 873                         onion_error_data: None,
 874                 }
 875         }
 876 }
 877
 878 #[derive(Clone)] // See Channel::revoke_and_ack for why, tl;dr: Rust bug
 879 #[cfg_attr(test, derive(PartialEq))]
 880 pub(super) struct HTLCFailReason(HTLCFailReasonRepr);
 881
 882 #[derive(Clone)] // See Channel::revoke_and_ack for why, tl;dr: Rust bug
 883 #[cfg_attr(test, derive(PartialEq))]
 884 enum HTLCFailReasonRepr {
 885         LightningError { err: msgs::OnionErrorPacket },
 886         Reason { failure_code: u16, data: Vec<u8> },
 887 }
 888
 889 impl core::fmt::Debug for HTLCFailReason {
 890         fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
 891                 match self.0 {
 892                         HTLCFailReasonRepr::Reason { ref failure_code, .. } => {
 893                                 write!(f, "HTLC error code {}", failure_code)
 894                         },
 895                         HTLCFailReasonRepr::LightningError { .. } => {
 896                                 write!(f, "pre-built LightningError")
 897                         },
 898                 }
 899         }
 900 }
 901
 902 impl Writeable for HTLCFailReason {
 903         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), crate::io::Error> {
 904                 self.0.write(writer)
 905         }
 906 }
 907 impl Readable for HTLCFailReason {
 908         fn read<R: Read>(reader: &mut R) -> Result<Self, msgs::DecodeError> {
 909                 Ok(Self(Readable::read(reader)?))
 910         }
 911 }
 912
 913 impl_writeable_tlv_based_enum!(HTLCFailReasonRepr,
 914         (0, LightningError) => {
 915                 (0, err, required),
 916         },
 917         (1, Reason) => {
 918                 (0, failure_code, required),
 919                 (2, data, required_vec),
 920         },
 921 ;);
 922
 923 impl HTLCFailReason {
 924         #[rustfmt::skip]
 925         pub(super) fn reason(failure_code: u16, data: Vec<u8>) -> Self {
 926                 const BADONION: u16 = 0x8000;
 927                 const PERM: u16 = 0x4000;
 928                 const NODE: u16 = 0x2000;
 929                 const UPDATE: u16 = 0x1000;
 930
 931                      if failure_code == 1  | PERM { debug_assert!(data.is_empty()) }
 932                 else if failure_code == 2  | NODE { debug_assert!(data.is_empty()) }
 933                 else if failure_code == 2  | PERM | NODE { debug_assert!(data.is_empty()) }
 934                 else if failure_code == 3  | PERM | NODE { debug_assert!(data.is_empty()) }
 935                 else if failure_code == 4  | BADONION | PERM { debug_assert_eq!(data.len(), 32) }
 936                 else if failure_code == 5  | BADONION | PERM { debug_assert_eq!(data.len(), 32) }
 937                 else if failure_code == 6  | BADONION | PERM { debug_assert_eq!(data.len(), 32) }
 938                 else if failure_code == 7  | UPDATE {
 939                         debug_assert_eq!(data.len() - 2, u16::from_be_bytes(data[0..2].try_into().unwrap()) as usize) }
 940                 else if failure_code == 8  | PERM { debug_assert!(data.is_empty()) }
 941                 else if failure_code == 9  | PERM { debug_assert!(data.is_empty()) }
 942                 else if failure_code == 10 | PERM { debug_assert!(data.is_empty()) }
 943                 else if failure_code == 11 | UPDATE {
 944                         debug_assert_eq!(data.len() - 2 - 8, u16::from_be_bytes(data[8..10].try_into().unwrap()) as usize) }
 945                 else if failure_code == 12 | 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 == 13 | UPDATE {
 948                         debug_assert_eq!(data.len() - 2 - 4, u16::from_be_bytes(data[4..6].try_into().unwrap()) as usize) }
 949                 else if failure_code == 14 | UPDATE {
 950                         debug_assert_eq!(data.len() - 2, u16::from_be_bytes(data[0..2].try_into().unwrap()) as usize) }
 951                 else if failure_code == 15 | PERM { debug_assert_eq!(data.len(), 12) }
 952                 else if failure_code == 18 { debug_assert_eq!(data.len(), 4) }
 953                 else if failure_code == 19 { debug_assert_eq!(data.len(), 8) }
 954                 else if failure_code == 20 | UPDATE {
 955                         debug_assert_eq!(data.len() - 2 - 2, u16::from_be_bytes(data[2..4].try_into().unwrap()) as usize) }
 956                 else if failure_code == 21 { debug_assert!(data.is_empty()) }
 957                 else if failure_code == 22 | PERM { debug_assert!(data.len() <= 11) }
 958                 else if failure_code == 23 { debug_assert!(data.is_empty()) }
 959                 else if failure_code & BADONION != 0 {
 960                         // We set some bogus BADONION failure codes in test, so ignore unknown ones.
 961                 }
 962                 else { debug_assert!(false, "Unknown failure code: {}", failure_code) }
 963
 964                 Self(HTLCFailReasonRepr::Reason { failure_code, data })
 965         }
 966
 967         pub(super) fn from_failure_code(failure_code: u16) -> Self {
 968                 Self::reason(failure_code, Vec::new())
 969         }
 970
 971         pub(super) fn from_msg(msg: &msgs::UpdateFailHTLC) -> Self {
 972                 Self(HTLCFailReasonRepr::LightningError { err: msg.reason.clone() })
 973         }
 974
 975         pub(super) fn get_encrypted_failure_packet(
 976                 &self, incoming_packet_shared_secret: &[u8; 32], phantom_shared_secret: &Option<[u8; 32]>,
 977         ) -> msgs::OnionErrorPacket {
 978                 match self.0 {
 979                         HTLCFailReasonRepr::Reason { ref failure_code, ref data } => {
 980                                 if let Some(phantom_ss) = phantom_shared_secret {
 981                                         let phantom_packet =
 982                                                 build_failure_packet(phantom_ss, *failure_code, &data[..]).encode();
 983                                         let encrypted_phantom_packet =
 984                                                 encrypt_failure_packet(phantom_ss, &phantom_packet);
 985                                         encrypt_failure_packet(
 986                                                 incoming_packet_shared_secret,
 987                                                 &encrypted_phantom_packet.data[..],
 988                                         )
 989                                 } else {
 990                                         let packet = build_failure_packet(
 991                                                 incoming_packet_shared_secret,
 992                                                 *failure_code,
 993                                                 &data[..],
 994                                         )
 995                                         .encode();
 996                                         encrypt_failure_packet(incoming_packet_shared_secret, &packet)
 997                                 }
 998                         },
 999                         HTLCFailReasonRepr::LightningError { ref err } => {
1000                                 encrypt_failure_packet(incoming_packet_shared_secret, &err.data)
1001                         },
1002                 }
1003         }
1004
1005         pub(super) fn decode_onion_failure<T: secp256k1::Signing, L: Deref>(
1006                 &self, secp_ctx: &Secp256k1<T>, logger: &L, htlc_source: &HTLCSource,
1007         ) -> DecodedOnionFailure
1008         where
1009                 L::Target: Logger,
1010         {
1011                 match self.0 {
1012                         HTLCFailReasonRepr::LightningError { ref err } => {
1013                                 process_onion_failure(secp_ctx, logger, &htlc_source, err.data.clone())
1014                         },
1015                         #[allow(unused)]
1016                         HTLCFailReasonRepr::Reason { ref failure_code, ref data, .. } => {
1017                                 // we get a fail_malformed_htlc from the first hop
1018                                 // TODO: We'd like to generate a NetworkUpdate for temporary
1019                                 // failures here, but that would be insufficient as find_route
1020                                 // generally ignores its view of our own channels as we provide them via
1021                                 // ChannelDetails.
1022                                 if let &HTLCSource::OutboundRoute { ref path, .. } = htlc_source {
1023                                         DecodedOnionFailure {
1024                                                 network_update: None,
1025                                                 payment_failed_permanently: false,
1026                                                 short_channel_id: Some(path.hops[0].short_channel_id),
1027                                                 failed_within_blinded_path: false,
1028                                                 #[cfg(test)]
1029                                                 onion_error_code: Some(*failure_code),
1030                                                 #[cfg(test)]
1031                                                 onion_error_data: Some(data.clone()),
1032                                         }
1033                                 } else {
1034                                         unreachable!();
1035                                 }
1036                         },
1037                 }
1038         }
1039 }
1040
1041 /// Allows `decode_next_hop` to return the next hop packet bytes for either payments or onion
1042 /// message forwards.
1043 pub(crate) trait NextPacketBytes: AsMut<[u8]> {
1044         fn new(len: usize) -> Self;
1045 }
1046
1047 impl NextPacketBytes for FixedSizeOnionPacket {
1048         fn new(_len: usize) -> Self {
1049                 Self([0 as u8; ONION_DATA_LEN])
1050         }
1051 }
1052
1053 impl NextPacketBytes for Vec<u8> {
1054         fn new(len: usize) -> Self {
1055                 vec![0 as u8; len]
1056         }
1057 }
1058
1059 /// Data decrypted from a payment's onion payload.
1060 pub(crate) enum Hop {
1061         /// This onion payload was for us, not for forwarding to a next-hop. Contains information for
1062         /// verifying the incoming payment.
1063         Receive(msgs::InboundOnionPayload),
1064         /// This onion payload needs to be forwarded to a next-hop.
1065         Forward {
1066                 /// Onion payload data used in forwarding the payment.
1067                 next_hop_data: msgs::InboundOnionPayload,
1068                 /// HMAC of the next hop's onion packet.
1069                 next_hop_hmac: [u8; 32],
1070                 /// Bytes of the onion packet we're forwarding.
1071                 new_packet_bytes: [u8; ONION_DATA_LEN],
1072         },
1073 }
1074
1075 /// Error returned when we fail to decode the onion packet.
1076 #[derive(Debug)]
1077 pub(crate) enum OnionDecodeErr {
1078         /// The HMAC of the onion packet did not match the hop data.
1079         Malformed { err_msg: &'static str, err_code: u16 },
1080         /// We failed to decode the onion payload.
1081         Relay { err_msg: &'static str, err_code: u16 },
1082 }
1083
1084 pub(crate) fn decode_next_payment_hop<NS: Deref>(
1085         shared_secret: [u8; 32], hop_data: &[u8], hmac_bytes: [u8; 32], payment_hash: PaymentHash,
1086         blinding_point: Option<PublicKey>, node_signer: &NS,
1087 ) -> Result<Hop, OnionDecodeErr>
1088 where
1089         NS::Target: NodeSigner,
1090 {
1091         match decode_next_hop(
1092                 shared_secret,
1093                 hop_data,
1094                 hmac_bytes,
1095                 Some(payment_hash),
1096                 (blinding_point, node_signer),
1097         ) {
1098                 Ok((next_hop_data, None)) => Ok(Hop::Receive(next_hop_data)),
1099                 Ok((next_hop_data, Some((next_hop_hmac, FixedSizeOnionPacket(new_packet_bytes))))) => {
1100                         Ok(Hop::Forward { next_hop_data, next_hop_hmac, new_packet_bytes })
1101                 },
1102                 Err(e) => Err(e),
1103         }
1104 }
1105
1106 /// Build a payment onion, returning the first hop msat and cltv values as well.
1107 /// `cur_block_height` should be set to the best known block height + 1.
1108 pub fn create_payment_onion<T: secp256k1::Signing>(
1109         secp_ctx: &Secp256k1<T>, path: &Path, session_priv: &SecretKey, total_msat: u64,
1110         recipient_onion: RecipientOnionFields, cur_block_height: u32, payment_hash: &PaymentHash,
1111         keysend_preimage: &Option<PaymentPreimage>, prng_seed: [u8; 32],
1112 ) -> Result<(msgs::OnionPacket, u64, u32), APIError> {
1113         let onion_keys = construct_onion_keys(&secp_ctx, &path, &session_priv).map_err(|_| {
1114                 APIError::InvalidRoute { err: "Pubkey along hop was maliciously selected".to_owned() }
1115         })?;
1116         let (onion_payloads, htlc_msat, htlc_cltv) = build_onion_payloads(
1117                 &path,
1118                 total_msat,
1119                 recipient_onion,
1120                 cur_block_height,
1121                 keysend_preimage,
1122         )?;
1123         let onion_packet = construct_onion_packet(onion_payloads, onion_keys, prng_seed, payment_hash)
1124                 .map_err(|_| APIError::InvalidRoute {
1125                         err: "Route size too large considering onion data".to_owned(),
1126                 })?;
1127         Ok((onion_packet, htlc_msat, htlc_cltv))
1128 }
1129
1130 pub(crate) fn decode_next_untagged_hop<T, R: ReadableArgs<T>, N: NextPacketBytes>(
1131         shared_secret: [u8; 32], hop_data: &[u8], hmac_bytes: [u8; 32], read_args: T,
1132 ) -> Result<(R, Option<([u8; 32], N)>), OnionDecodeErr> {
1133         decode_next_hop(shared_secret, hop_data, hmac_bytes, None, read_args)
1134 }
1135
1136 fn decode_next_hop<T, R: ReadableArgs<T>, N: NextPacketBytes>(
1137         shared_secret: [u8; 32], hop_data: &[u8], hmac_bytes: [u8; 32],
1138         payment_hash: Option<PaymentHash>, read_args: T,
1139 ) -> Result<(R, Option<([u8; 32], N)>), OnionDecodeErr> {
1140         let (rho, mu) = gen_rho_mu_from_shared_secret(&shared_secret);
1141         let mut hmac = HmacEngine::<Sha256>::new(&mu);
1142         hmac.input(hop_data);
1143         if let Some(tag) = payment_hash {
1144                 hmac.input(&tag.0[..]);
1145         }
1146         if !fixed_time_eq(&Hmac::from_engine(hmac).to_byte_array(), &hmac_bytes) {
1147                 return Err(OnionDecodeErr::Malformed {
1148                         err_msg: "HMAC Check failed",
1149                         err_code: 0x8000 | 0x4000 | 5,
1150                 });
1151         }
1152
1153         let mut chacha = ChaCha20::new(&rho, &[0u8; 8]);
1154         let mut chacha_stream = ChaChaReader { chacha: &mut chacha, read: Cursor::new(&hop_data[..]) };
1155         match R::read(&mut chacha_stream, read_args) {
1156                 Err(err) => {
1157                         let error_code = match err {
1158                                 // Unknown realm byte
1159                                 msgs::DecodeError::UnknownVersion => 0x4000 | 1,
1160                                 // invalid_onion_payload
1161                                 msgs::DecodeError::UnknownRequiredFeature
1162                                 | msgs::DecodeError::InvalidValue
1163                                 | msgs::DecodeError::ShortRead => 0x4000 | 22,
1164                                 // Should never happen
1165                                 _ => 0x2000 | 2,
1166                         };
1167                         return Err(OnionDecodeErr::Relay {
1168                                 err_msg: "Unable to decode our hop data",
1169                                 err_code: error_code,
1170                         });
1171                 },
1172                 Ok(msg) => {
1173                         let mut hmac = [0; 32];
1174                         if let Err(_) = chacha_stream.read_exact(&mut hmac[..]) {
1175                                 return Err(OnionDecodeErr::Relay {
1176                                         err_msg: "Unable to decode our hop data",
1177                                         err_code: 0x4000 | 22,
1178                                 });
1179                         }
1180                         if hmac == [0; 32] {
1181                                 #[cfg(test)]
1182                                 {
1183                                         if chacha_stream.read.position() < hop_data.len() as u64 - 64 {
1184                                                 // In tests, make sure that the initial onion packet data is, at least, non-0.
1185                                                 // We could do some fancy randomness test here, but, ehh, whatever.
1186                                                 // This checks for the issue where you can calculate the path length given the
1187                                                 // onion data as all the path entries that the originator sent will be here
1188                                                 // as-is (and were originally 0s).
1189                                                 // Of course reverse path calculation is still pretty easy given naive routing
1190                                                 // algorithms, but this fixes the most-obvious case.
1191                                                 let mut next_bytes = [0; 32];
1192                                                 chacha_stream.read_exact(&mut next_bytes).unwrap();
1193                                                 assert_ne!(next_bytes[..], [0; 32][..]);
1194                                                 chacha_stream.read_exact(&mut next_bytes).unwrap();
1195                                                 assert_ne!(next_bytes[..], [0; 32][..]);
1196                                         }
1197                                 }
1198                                 return Ok((msg, None)); // We are the final destination for this packet
1199                         } else {
1200                                 let mut new_packet_bytes = N::new(hop_data.len());
1201                                 let read_pos = hop_data.len() - chacha_stream.read.position() as usize;
1202                                 chacha_stream.read_exact(&mut new_packet_bytes.as_mut()[..read_pos]).unwrap();
1203                                 #[cfg(debug_assertions)]
1204                                 {
1205                                         // Check two things:
1206                                         // a) that the behavior of our stream here will return Ok(0) even if the TLV
1207                                         //    read above emptied out our buffer and the unwrap() wont needlessly panic
1208                                         // b) that we didn't somehow magically end up with extra data.
1209                                         let mut t = [0; 1];
1210                                         debug_assert!(chacha_stream.read(&mut t).unwrap() == 0);
1211                                 }
1212                                 // Once we've emptied the set of bytes our peer gave us, encrypt 0 bytes until we
1213                                 // fill the onion hop data we'll forward to our next-hop peer.
1214                                 chacha_stream.chacha.process_in_place(&mut new_packet_bytes.as_mut()[read_pos..]);
1215                                 return Ok((msg, Some((hmac, new_packet_bytes)))); // This packet needs forwarding
1216                         }
1217                 },
1218         }
1219 }
1220
1221 #[cfg(test)]
1222 mod tests {
1223         use crate::io;
1224         use crate::ln::features::{ChannelFeatures, NodeFeatures};
1225         use crate::ln::msgs;
1226         use crate::ln::PaymentHash;
1227         use crate::prelude::*;
1228         use crate::routing::router::{Path, Route, RouteHop};
1229         use crate::util::ser::{VecWriter, Writeable, Writer};
1230
1231         use bitcoin::hashes::hex::FromHex;
1232         use bitcoin::secp256k1::Secp256k1;
1233         use bitcoin::secp256k1::{PublicKey, SecretKey};
1234
1235         use super::OnionKeys;
1236
1237         fn get_test_session_key() -> SecretKey {
1238                 let hex = "4141414141414141414141414141414141414141414141414141414141414141";
1239                 SecretKey::from_slice(&<Vec<u8>>::from_hex(hex).unwrap()[..]).unwrap()
1240         }
1241
1242         fn build_test_onion_keys() -> Vec<OnionKeys> {
1243                 // Keys from BOLT 4, used in both test vector tests
1244                 let secp_ctx = Secp256k1::new();
1245
1246                 let route = Route {
1247                         paths: vec![Path { hops: vec![
1248                                         RouteHop {
1249                                                 pubkey: PublicKey::from_slice(&<Vec<u8>>::from_hex("02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619").unwrap()[..]).unwrap(),
1250                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
1251                                                 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.
1252                                         },
1253                                         RouteHop {
1254                                                 pubkey: PublicKey::from_slice(&<Vec<u8>>::from_hex("0324653eac434488002cc06bbfb7f10fe18991e35f9fe4302dbea6d2353dc0ab1c").unwrap()[..]).unwrap(),
1255                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
1256                                                 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.
1257                                         },
1258                                         RouteHop {
1259                                                 pubkey: PublicKey::from_slice(&<Vec<u8>>::from_hex("027f31ebc5462c1fdce1b737ecff52d37d75dea43ce11c74d25aa297165faa2007").unwrap()[..]).unwrap(),
1260                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
1261                                                 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.
1262                                         },
1263                                         RouteHop {
1264                                                 pubkey: PublicKey::from_slice(&<Vec<u8>>::from_hex("032c0b7cf95324a07d05398b240174dc0c2be444d96b159aa6c7f7b1e668680991").unwrap()[..]).unwrap(),
1265                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
1266                                                 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.
1267                                         },
1268                                         RouteHop {
1269                                                 pubkey: PublicKey::from_slice(&<Vec<u8>>::from_hex("02edabbd16b41c8371b92ef2f04c1185b4f03b6dcd52ba9b78d9d7c89c8f221145").unwrap()[..]).unwrap(),
1270                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
1271                                                 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.
1272                                         },
1273                         ], blinded_tail: None }],
1274                         route_params: None,
1275                 };
1276
1277                 let onion_keys =
1278                         super::construct_onion_keys(&secp_ctx, &route.paths[0], &get_test_session_key())
1279                                 .unwrap();
1280                 assert_eq!(onion_keys.len(), route.paths[0].hops.len());
1281                 onion_keys
1282         }
1283
1284         #[test]
1285         fn onion_vectors() {
1286                 let onion_keys = build_test_onion_keys();
1287
1288                 // Test generation of ephemeral keys and secrets. These values used to be part of the BOLT4
1289                 // test vectors, but have since been removed. We keep them as they provide test coverage.
1290                 let hex = "53eb63ea8a3fec3b3cd433b85cd62a4b145e1dda09391b348c4e1cd36a03ea66";
1291                 assert_eq!(
1292                         onion_keys[0].shared_secret.secret_bytes(),
1293                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1294                 );
1295
1296                 let hex = "2ec2e5da605776054187180343287683aa6a51b4b1c04d6dd49c45d8cffb3c36";
1297                 assert_eq!(onion_keys[0].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
1298
1299                 let hex = "02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619";
1300                 assert_eq!(
1301                         onion_keys[0].ephemeral_pubkey.serialize()[..],
1302                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1303                 );
1304
1305                 let hex = "ce496ec94def95aadd4bec15cdb41a740c9f2b62347c4917325fcc6fb0453986";
1306                 assert_eq!(onion_keys[0].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1307
1308                 let hex = "b57061dc6d0a2b9f261ac410c8b26d64ac5506cbba30267a649c28c179400eba";
1309                 assert_eq!(onion_keys[0].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1310
1311                 let hex = "a6519e98832a0b179f62123b3567c106db99ee37bef036e783263602f3488fae";
1312                 assert_eq!(
1313                         onion_keys[1].shared_secret.secret_bytes(),
1314                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1315                 );
1316
1317                 let hex = "bf66c28bc22e598cfd574a1931a2bafbca09163df2261e6d0056b2610dab938f";
1318                 assert_eq!(onion_keys[1].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
1319
1320                 let hex = "028f9438bfbf7feac2e108d677e3a82da596be706cc1cf342b75c7b7e22bf4e6e2";
1321                 assert_eq!(
1322                         onion_keys[1].ephemeral_pubkey.serialize()[..],
1323                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1324                 );
1325
1326                 let hex = "450ffcabc6449094918ebe13d4f03e433d20a3d28a768203337bc40b6e4b2c59";
1327                 assert_eq!(onion_keys[1].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1328
1329                 let hex = "05ed2b4a3fb023c2ff5dd6ed4b9b6ea7383f5cfe9d59c11d121ec2c81ca2eea9";
1330                 assert_eq!(onion_keys[1].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1331
1332                 let hex = "3a6b412548762f0dbccce5c7ae7bb8147d1caf9b5471c34120b30bc9c04891cc";
1333                 assert_eq!(
1334                         onion_keys[2].shared_secret.secret_bytes(),
1335                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1336                 );
1337
1338                 let hex = "a1f2dadd184eb1627049673f18c6325814384facdee5bfd935d9cb031a1698a5";
1339                 assert_eq!(onion_keys[2].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
1340
1341                 let hex = "03bfd8225241ea71cd0843db7709f4c222f62ff2d4516fd38b39914ab6b83e0da0";
1342                 assert_eq!(
1343                         onion_keys[2].ephemeral_pubkey.serialize()[..],
1344                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1345                 );
1346
1347                 let hex = "11bf5c4f960239cb37833936aa3d02cea82c0f39fd35f566109c41f9eac8deea";
1348                 assert_eq!(onion_keys[2].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1349
1350                 let hex = "caafe2820fa00eb2eeb78695ae452eba38f5a53ed6d53518c5c6edf76f3f5b78";
1351                 assert_eq!(onion_keys[2].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1352
1353                 let hex = "21e13c2d7cfe7e18836df50872466117a295783ab8aab0e7ecc8c725503ad02d";
1354                 assert_eq!(
1355                         onion_keys[3].shared_secret.secret_bytes(),
1356                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1357                 );
1358
1359                 let hex = "7cfe0b699f35525029ae0fa437c69d0f20f7ed4e3916133f9cacbb13c82ff262";
1360                 assert_eq!(onion_keys[3].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
1361
1362                 let hex = "031dde6926381289671300239ea8e57ffaf9bebd05b9a5b95beaf07af05cd43595";
1363                 assert_eq!(
1364                         onion_keys[3].ephemeral_pubkey.serialize()[..],
1365                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1366                 );
1367
1368                 let hex = "cbe784ab745c13ff5cffc2fbe3e84424aa0fd669b8ead4ee562901a4a4e89e9e";
1369                 assert_eq!(onion_keys[3].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1370
1371                 let hex = "5052aa1b3d9f0655a0932e50d42f0c9ba0705142c25d225515c45f47c0036ee9";
1372                 assert_eq!(onion_keys[3].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1373
1374                 let hex = "b5756b9b542727dbafc6765a49488b023a725d631af688fc031217e90770c328";
1375                 assert_eq!(
1376                         onion_keys[4].shared_secret.secret_bytes(),
1377                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1378                 );
1379
1380                 let hex = "c96e00dddaf57e7edcd4fb5954be5b65b09f17cb6d20651b4e90315be5779205";
1381                 assert_eq!(onion_keys[4].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
1382
1383                 let hex = "03a214ebd875aab6ddfd77f22c5e7311d7f77f17a169e599f157bbcdae8bf071f4";
1384                 assert_eq!(
1385                         onion_keys[4].ephemeral_pubkey.serialize()[..],
1386                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1387                 );
1388
1389                 let hex = "034e18b8cc718e8af6339106e706c52d8df89e2b1f7e9142d996acf88df8799b";
1390                 assert_eq!(onion_keys[4].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1391
1392                 let hex = "8e45e5c61c2b24cb6382444db6698727afb063adecd72aada233d4bf273d975a";
1393                 assert_eq!(onion_keys[4].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1394
1395                 // Packet creation test vectors from BOLT 4 (see
1396                 // https://github.com/lightning/bolts/blob/16973e2b857e853308cafd59e42fa830d75b1642/bolt04/onion-test.json).
1397                 // Note that we represent the test vector payloads 2 and 5 through RawOnionHopData::data
1398                 // with raw hex instead of our in-memory enums, as the payloads contains custom types, and
1399                 // we have no way of representing that with our enums.
1400                 let payloads = vec!(
1401                         RawOnionHopData::new(msgs::OutboundOnionPayload::Forward {
1402                                 short_channel_id: 1,
1403                                 amt_to_forward: 15000,
1404                                 outgoing_cltv_value: 1500,
1405                         }),
1406                         /*
1407                         The second payload is represented by raw hex as it contains custom type data. Content:
1408                         1. length "52" (payload_length 82).
1409
1410                         The first part of the payload has the `NonFinalNode` format, with content as follows:
1411                         2. amt_to_forward "020236b0"
1412                            02 (type amt_to_forward) 02 (length 2) 36b0 (value 14000)
1413                         3. outgoing_cltv_value "04020578"
1414                            04 (type outgoing_cltv_value) 02 (length 2) 0578 (value 1400)
1415                         4. short_channel_id "06080000000000000002"
1416                            06 (type short_channel_id) 08 (length 8) 0000000000000002 (value 2)
1417
1418                         The rest of the payload is custom type data:
1419                         5. custom_record "fd02013c0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f"
1420                         */
1421                         RawOnionHopData {
1422                                 data: <Vec<u8>>::from_hex("52020236b00402057806080000000000000002fd02013c0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f").unwrap(),
1423                         },
1424                         RawOnionHopData::new(msgs::OutboundOnionPayload::Forward {
1425                                 short_channel_id: 3,
1426                                 amt_to_forward: 12500,
1427                                 outgoing_cltv_value: 1250,
1428                         }),
1429                         RawOnionHopData::new(msgs::OutboundOnionPayload::Forward {
1430                                 short_channel_id: 4,
1431                                 amt_to_forward: 10000,
1432                                 outgoing_cltv_value: 1000,
1433                         }),
1434                         /*
1435                         The fifth payload is represented by raw hex as it contains custom type data. Content:
1436                         1. length "fd0110" (payload_length 272).
1437
1438                         The first part of the payload has the `FinalNode` format, with content as follows:
1439                         1. amt_to_forward "02022710"
1440                            02 (type amt_to_forward) 02 (length 2) 2710 (value 10000)
1441                         2. outgoing_cltv_value "040203e8"
1442                            04 (type outgoing_cltv_value) 02 (length 2) 03e8 (value 1000)
1443                         3. payment_data "082224a33562c54507a9334e79f0dc4f17d407e6d7c61f0e2f3d0d38599502f617042710"
1444                            08 (type short_channel_id) 22 (length 34) 24a33562c54507a9334e79f0dc4f17d407e6d7c61f0e2f3d0d38599502f61704 (payment_secret) 2710 (total_msat value 10000)
1445
1446                         The rest of the payload is custom type data:
1447                         4. custom_record "fd012de02a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a"
1448                         */
1449                         RawOnionHopData {
1450                                 data: <Vec<u8>>::from_hex("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").unwrap(),
1451                         },
1452                 );
1453
1454                 // Verify that the serialized OnionHopDataFormat::NonFinalNode tlv payloads matches the test vectors
1455                 let mut w = VecWriter(Vec::new());
1456                 payloads[0].write(&mut w).unwrap();
1457                 let hop_1_serialized_payload = w.0;
1458                 let hex = "1202023a98040205dc06080000000000000001";
1459                 let expected_serialized_hop_1_payload = &<Vec<u8>>::from_hex(hex).unwrap()[..];
1460                 assert_eq!(hop_1_serialized_payload, expected_serialized_hop_1_payload);
1461
1462                 w = VecWriter(Vec::new());
1463                 payloads[2].write(&mut w).unwrap();
1464                 let hop_3_serialized_payload = w.0;
1465                 let hex = "12020230d4040204e206080000000000000003";
1466                 let expected_serialized_hop_3_payload = &<Vec<u8>>::from_hex(hex).unwrap()[..];
1467                 assert_eq!(hop_3_serialized_payload, expected_serialized_hop_3_payload);
1468
1469                 w = VecWriter(Vec::new());
1470                 payloads[3].write(&mut w).unwrap();
1471                 let hop_4_serialized_payload = w.0;
1472                 let hex = "1202022710040203e806080000000000000004";
1473                 let expected_serialized_hop_4_payload = &<Vec<u8>>::from_hex(hex).unwrap()[..];
1474                 assert_eq!(hop_4_serialized_payload, expected_serialized_hop_4_payload);
1475
1476                 let pad_keytype_seed =
1477                         super::gen_pad_from_shared_secret(&get_test_session_key().secret_bytes());
1478
1479                 let packet: msgs::OnionPacket = super::construct_onion_packet_with_writable_hopdata::<_>(
1480                         payloads,
1481                         onion_keys,
1482                         pad_keytype_seed,
1483                         &PaymentHash([0x42; 32]),
1484                 )
1485                 .unwrap();
1486
1487                 let hex = 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
1488                 assert_eq!(packet.encode(), <Vec<u8>>::from_hex(hex).unwrap());
1489         }
1490
1491         #[test]
1492         fn test_failure_packet_onion() {
1493                 // Returning Errors test vectors from BOLT 4
1494
1495                 let onion_keys = build_test_onion_keys();
1496                 let onion_error =
1497                         super::build_failure_packet(onion_keys[4].shared_secret.as_ref(), 0x2002, &[0; 0]);
1498                 let hex = "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";
1499                 assert_eq!(onion_error.encode(), <Vec<u8>>::from_hex(hex).unwrap());
1500
1501                 let onion_packet_1 = super::encrypt_failure_packet(
1502                         onion_keys[4].shared_secret.as_ref(),
1503                         &onion_error.encode()[..],
1504                 );
1505                 let hex = "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";
1506                 assert_eq!(onion_packet_1.data, <Vec<u8>>::from_hex(hex).unwrap());
1507
1508                 let onion_packet_2 = super::encrypt_failure_packet(
1509                         onion_keys[3].shared_secret.as_ref(),
1510                         &onion_packet_1.data[..],
1511                 );
1512                 let hex = "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";
1513                 assert_eq!(onion_packet_2.data, <Vec<u8>>::from_hex(hex).unwrap());
1514
1515                 let onion_packet_3 = super::encrypt_failure_packet(
1516                         onion_keys[2].shared_secret.as_ref(),
1517                         &onion_packet_2.data[..],
1518                 );
1519                 let hex = "a5d3e8634cfe78b2307d87c6d90be6fe7855b4f2cc9b1dfb19e92e4b79103f61ff9ac25f412ddfb7466e74f81b3e545563cdd8f5524dae873de61d7bdfccd496af2584930d2b566b4f8d3881f8c043df92224f38cf094cfc09d92655989531524593ec6d6caec1863bdfaa79229b5020acc034cd6deeea1021c50586947b9b8e6faa83b81fbfa6133c0af5d6b07c017f7158fa94f0d206baf12dda6b68f785b773b360fd0497e16cc402d779c8d48d0fa6315536ef0660f3f4e1865f5b38ea49c7da4fd959de4e83ff3ab686f059a45c65ba2af4a6a79166aa0f496bf04d06987b6d2ea205bdb0d347718b9aeff5b61dfff344993a275b79717cd815b6ad4c0beb568c4ac9c36ff1c315ec1119a1993c4b61e6eaa0375e0aaf738ac691abd3263bf937e3";
1520                 assert_eq!(onion_packet_3.data, <Vec<u8>>::from_hex(hex).unwrap());
1521
1522                 let onion_packet_4 = super::encrypt_failure_packet(
1523                         onion_keys[1].shared_secret.as_ref(),
1524                         &onion_packet_3.data[..],
1525                 );
1526                 let hex = "aac3200c4968f56b21f53e5e374e3a2383ad2b1b6501bbcc45abc31e59b26881b7dfadbb56ec8dae8857add94e6702fb4c3a4de22e2e669e1ed926b04447fc73034bb730f4932acd62727b75348a648a1128744657ca6a4e713b9b646c3ca66cac02cdab44dd3439890ef3aaf61708714f7375349b8da541b2548d452d84de7084bb95b3ac2345201d624d31f4d52078aa0fa05a88b4e20202bd2b86ac5b52919ea305a8949de95e935eed0319cf3cf19ebea61d76ba92532497fcdc9411d06bcd4275094d0a4a3c5d3a945e43305a5a9256e333e1f64dbca5fcd4e03a39b9012d197506e06f29339dfee3331995b21615337ae060233d39befea925cc262873e0530408e6990f1cbd233a150ef7b004ff6166c70c68d9f8c853c1abca640b8660db2921";
1527                 assert_eq!(onion_packet_4.data, <Vec<u8>>::from_hex(hex).unwrap());
1528
1529                 let onion_packet_5 = super::encrypt_failure_packet(
1530                         onion_keys[0].shared_secret.as_ref(),
1531                         &onion_packet_4.data[..],
1532                 );
1533                 let hex = "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";
1534                 assert_eq!(onion_packet_5.data, <Vec<u8>>::from_hex(hex).unwrap());
1535         }
1536
1537         struct RawOnionHopData {
1538                 data: Vec<u8>,
1539         }
1540         impl RawOnionHopData {
1541                 fn new(orig: msgs::OutboundOnionPayload) -> Self {
1542                         Self { data: orig.encode() }
1543                 }
1544         }
1545         impl Writeable for RawOnionHopData {
1546                 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
1547                         writer.write_all(&self.data[..])
1548                 }
1549         }
1550 }