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

   1 // This file is Copyright its original authors, visible in version control
   2 // history.
   3 //
   4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
   5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
   7 // You may not use this file except in accordance with one or both of these
   8 // licenses.
   9
  10 use crate::blinded_path::BlindedHop;
  11 use crate::crypto::chacha20::ChaCha20;
  12 use crate::crypto::streams::ChaChaReader;
  13 use crate::ln::channel::TOTAL_BITCOIN_SUPPLY_SATOSHIS;
  14 use crate::ln::channelmanager::{HTLCSource, RecipientOnionFields};
  15 use crate::ln::features::{ChannelFeatures, NodeFeatures};
  16 use crate::ln::msgs;
  17 use crate::ln::types::{PaymentHash, PaymentPreimage};
  18 use crate::ln::wire::Encode;
  19 use crate::routing::gossip::NetworkUpdate;
  20 use crate::routing::router::{Path, RouteHop, RouteParameters};
  21 use crate::sign::NodeSigner;
  22 use crate::util::errors::{self, APIError};
  23 use crate::util::logger::Logger;
  24 use crate::util::ser::{LengthCalculatingWriter, Readable, ReadableArgs, Writeable, Writer};
  25
  26 use bitcoin::hashes::cmp::fixed_time_eq;
  27 use bitcoin::hashes::hmac::{Hmac, HmacEngine};
  28 use bitcoin::hashes::sha256::Hash as Sha256;
  29 use bitcoin::hashes::{Hash, HashEngine};
  30
  31 use bitcoin::secp256k1;
  32 use bitcoin::secp256k1::ecdh::SharedSecret;
  33 use bitcoin::secp256k1::{PublicKey, Scalar, Secp256k1, SecretKey};
  34
  35 use crate::io::{Cursor, Read};
  36 use core::ops::Deref;
  37
  38 #[allow(unused_imports)]
  39 use crate::prelude::*;
  40
  41 pub(crate) struct OnionKeys {
  42         #[cfg(test)]
  43         pub(crate) shared_secret: SharedSecret,
  44         #[cfg(test)]
  45         pub(crate) blinding_factor: [u8; 32],
  46         pub(crate) ephemeral_pubkey: PublicKey,
  47         pub(crate) rho: [u8; 32],
  48         pub(crate) mu: [u8; 32],
  49 }
  50
  51 #[inline]
  52 pub(crate) fn gen_rho_from_shared_secret(shared_secret: &[u8]) -> [u8; 32] {
  53         assert_eq!(shared_secret.len(), 32);
  54         let mut hmac = HmacEngine::<Sha256>::new(&[0x72, 0x68, 0x6f]); // rho
  55         hmac.input(&shared_secret);
  56         Hmac::from_engine(hmac).to_byte_array()
  57 }
  58
  59 #[inline]
  60 pub(crate) fn gen_rho_mu_from_shared_secret(shared_secret: &[u8]) -> ([u8; 32], [u8; 32]) {
  61         assert_eq!(shared_secret.len(), 32);
  62         let mut engine_rho = HmacEngine::<Sha256>::new(b"rho");
  63         engine_rho.input(&shared_secret);
  64         let hmac_rho = Hmac::from_engine(engine_rho).to_byte_array();
  65
  66         let mut engine_mu = HmacEngine::<Sha256>::new(b"mu");
  67         engine_mu.input(&shared_secret);
  68         let hmac_mu = Hmac::from_engine(engine_mu).to_byte_array();
  69
  70         (hmac_rho, hmac_mu)
  71 }
  72
  73 #[inline]
  74 pub(super) fn gen_um_from_shared_secret(shared_secret: &[u8]) -> [u8; 32] {
  75         assert_eq!(shared_secret.len(), 32);
  76         let mut hmac = HmacEngine::<Sha256>::new(&[0x75, 0x6d]); // um
  77         hmac.input(&shared_secret);
  78         Hmac::from_engine(hmac).to_byte_array()
  79 }
  80
  81 #[inline]
  82 pub(super) fn gen_ammag_from_shared_secret(shared_secret: &[u8]) -> [u8; 32] {
  83         assert_eq!(shared_secret.len(), 32);
  84         let mut hmac = HmacEngine::<Sha256>::new(&[0x61, 0x6d, 0x6d, 0x61, 0x67]); // ammag
  85         hmac.input(&shared_secret);
  86         Hmac::from_engine(hmac).to_byte_array()
  87 }
  88
  89 #[cfg(test)]
  90 #[inline]
  91 pub(super) fn gen_pad_from_shared_secret(shared_secret: &[u8]) -> [u8; 32] {
  92         assert_eq!(shared_secret.len(), 32);
  93         let mut hmac = HmacEngine::<Sha256>::new(&[0x70, 0x61, 0x64]); // pad
  94         hmac.input(&shared_secret);
  95         Hmac::from_engine(hmac).to_byte_array()
  96 }
  97
  98 /// Calculates a pubkey for the next hop, such as the next hop's packet pubkey or blinding point.
  99 pub(crate) fn next_hop_pubkey<T: secp256k1::Verification>(
 100         secp_ctx: &Secp256k1<T>, curr_pubkey: PublicKey, shared_secret: &[u8],
 101 ) -> Result<PublicKey, secp256k1::Error> {
 102         let blinding_factor = {
 103                 let mut sha = Sha256::engine();
 104                 sha.input(&curr_pubkey.serialize()[..]);
 105                 sha.input(shared_secret);
 106                 Sha256::from_engine(sha).to_byte_array()
 107         };
 108
 109         curr_pubkey.mul_tweak(secp_ctx, &Scalar::from_be_bytes(blinding_factor).unwrap())
 110 }
 111
 112 // can only fail if an intermediary hop has an invalid public key or session_priv is invalid
 113 #[inline]
 114 pub(super) fn construct_onion_keys_callback<T, FType>(
 115         secp_ctx: &Secp256k1<T>, path: &Path, session_priv: &SecretKey, mut callback: FType,
 116 ) -> Result<(), secp256k1::Error>
 117 where
 118         T: secp256k1::Signing,
 119         FType: FnMut(SharedSecret, [u8; 32], PublicKey, Option<&RouteHop>, usize),
 120 {
 121         let mut blinded_priv = session_priv.clone();
 122         let mut blinded_pub = PublicKey::from_secret_key(secp_ctx, &blinded_priv);
 123
 124         let unblinded_hops_iter = path.hops.iter().map(|h| (&h.pubkey, Some(h)));
 125         let blinded_pks_iter = path
 126                 .blinded_tail
 127                 .as_ref()
 128                 .map(|t| t.hops.iter())
 129                 .unwrap_or([].iter())
 130                 .skip(1) // Skip the intro node because it's included in the unblinded hops
 131                 .map(|h| (&h.blinded_node_id, None));
 132         for (idx, (pubkey, route_hop_opt)) in unblinded_hops_iter.chain(blinded_pks_iter).enumerate() {
 133                 let shared_secret = SharedSecret::new(pubkey, &blinded_priv);
 134
 135                 let mut sha = Sha256::engine();
 136                 sha.input(&blinded_pub.serialize()[..]);
 137                 sha.input(shared_secret.as_ref());
 138                 let blinding_factor = Sha256::from_engine(sha).to_byte_array();
 139
 140                 let ephemeral_pubkey = blinded_pub;
 141
 142                 blinded_priv = blinded_priv.mul_tweak(&Scalar::from_be_bytes(blinding_factor).unwrap())?;
 143                 blinded_pub = PublicKey::from_secret_key(secp_ctx, &blinded_priv);
 144
 145                 callback(shared_secret, blinding_factor, ephemeral_pubkey, route_hop_opt, idx);
 146         }
 147
 148         Ok(())
 149 }
 150
 151 // can only fail if an intermediary hop has an invalid public key or session_priv is invalid
 152 pub(super) fn construct_onion_keys<T: secp256k1::Signing>(
 153         secp_ctx: &Secp256k1<T>, path: &Path, session_priv: &SecretKey,
 154 ) -> Result<Vec<OnionKeys>, secp256k1::Error> {
 155         let mut res = Vec::with_capacity(path.hops.len());
 156
 157         construct_onion_keys_callback(
 158                 secp_ctx,
 159                 &path,
 160                 session_priv,
 161                 |shared_secret, _blinding_factor, ephemeral_pubkey, _, _| {
 162                         let (rho, mu) = gen_rho_mu_from_shared_secret(shared_secret.as_ref());
 163
 164                         res.push(OnionKeys {
 165                                 #[cfg(test)]
 166                                 shared_secret,
 167                                 #[cfg(test)]
 168                                 blinding_factor: _blinding_factor,
 169                                 ephemeral_pubkey,
 170                                 rho,
 171                                 mu,
 172                         });
 173                 },
 174         )?;
 175
 176         Ok(res)
 177 }
 178
 179 /// returns the hop data, as well as the first-hop value_msat and CLTV value we should send.
 180 pub(super) fn build_onion_payloads<'a>(
 181         path: &'a Path, total_msat: u64, recipient_onion: &'a RecipientOnionFields,
 182         starting_htlc_offset: u32, keysend_preimage: &Option<PaymentPreimage>,
 183 ) -> Result<(Vec<msgs::OutboundOnionPayload<'a>>, u64, u32), APIError> {
 184         let mut res: Vec<msgs::OutboundOnionPayload> = Vec::with_capacity(
 185                 path.hops.len() + path.blinded_tail.as_ref().map_or(0, |t| t.hops.len()),
 186         );
 187         let blinded_tail_with_hop_iter = path.blinded_tail.as_ref().map(|bt| BlindedTailHopIter {
 188                 hops: bt.hops.iter(),
 189                 blinding_point: bt.blinding_point,
 190                 final_value_msat: bt.final_value_msat,
 191                 excess_final_cltv_expiry_delta: bt.excess_final_cltv_expiry_delta,
 192         });
 193
 194         let (value_msat, cltv) = build_onion_payloads_callback(
 195                 path.hops.iter(),
 196                 blinded_tail_with_hop_iter,
 197                 total_msat,
 198                 recipient_onion,
 199                 starting_htlc_offset,
 200                 keysend_preimage,
 201                 |action, payload| match action {
 202                         PayloadCallbackAction::PushBack => res.push(payload),
 203                         PayloadCallbackAction::PushFront => res.insert(0, payload),
 204                 },
 205         )?;
 206         Ok((res, value_msat, cltv))
 207 }
 208
 209 struct BlindedTailHopIter<'a, I: Iterator<Item = &'a BlindedHop>> {
 210         hops: I,
 211         blinding_point: PublicKey,
 212         final_value_msat: u64,
 213         excess_final_cltv_expiry_delta: u32,
 214 }
 215 enum PayloadCallbackAction {
 216         PushBack,
 217         PushFront,
 218 }
 219 fn build_onion_payloads_callback<'a, H, B, F>(
 220         hops: H, mut blinded_tail: Option<BlindedTailHopIter<'a, B>>, total_msat: u64,
 221         recipient_onion: &'a RecipientOnionFields, starting_htlc_offset: u32,
 222         keysend_preimage: &Option<PaymentPreimage>, mut callback: F,
 223 ) -> Result<(u64, u32), APIError>
 224 where
 225         H: DoubleEndedIterator<Item = &'a RouteHop>,
 226         B: ExactSizeIterator<Item = &'a BlindedHop>,
 227         F: FnMut(PayloadCallbackAction, msgs::OutboundOnionPayload<'a>),
 228 {
 229         let mut cur_value_msat = 0u64;
 230         let mut cur_cltv = starting_htlc_offset;
 231         let mut last_short_channel_id = 0;
 232
 233         for (idx, hop) in hops.rev().enumerate() {
 234                 // First hop gets special values so that it can check, on receipt, that everything is
 235                 // exactly as it should be (and the next hop isn't trying to probe to find out if we're
 236                 // the intended recipient).
 237                 let value_msat = if cur_value_msat == 0 { hop.fee_msat } else { cur_value_msat };
 238                 let cltv = if cur_cltv == starting_htlc_offset {
 239                         hop.cltv_expiry_delta + starting_htlc_offset
 240                 } else {
 241                         cur_cltv
 242                 };
 243                 if idx == 0 {
 244                         if let Some(BlindedTailHopIter {
 245                                 blinding_point,
 246                                 hops,
 247                                 final_value_msat,
 248                                 excess_final_cltv_expiry_delta,
 249                                 ..
 250                         }) = blinded_tail.take()
 251                         {
 252                                 let mut blinding_point = Some(blinding_point);
 253                                 let hops_len = hops.len();
 254                                 for (i, blinded_hop) in hops.enumerate() {
 255                                         if i == hops_len - 1 {
 256                                                 cur_value_msat += final_value_msat;
 257                                                 callback(
 258                                                         PayloadCallbackAction::PushBack,
 259                                                         msgs::OutboundOnionPayload::BlindedReceive {
 260                                                                 sender_intended_htlc_amt_msat: final_value_msat,
 261                                                                 total_msat,
 262                                                                 cltv_expiry_height: cur_cltv + excess_final_cltv_expiry_delta,
 263                                                                 encrypted_tlvs: &blinded_hop.encrypted_payload,
 264                                                                 intro_node_blinding_point: blinding_point.take(),
 265                                                                 keysend_preimage: *keysend_preimage,
 266                                                                 custom_tlvs: &recipient_onion.custom_tlvs,
 267                                                         },
 268                                                 );
 269                                         } else {
 270                                                 callback(
 271                                                         PayloadCallbackAction::PushBack,
 272                                                         msgs::OutboundOnionPayload::BlindedForward {
 273                                                                 encrypted_tlvs: &blinded_hop.encrypted_payload,
 274                                                                 intro_node_blinding_point: blinding_point.take(),
 275                                                         },
 276                                                 );
 277                                         }
 278                                 }
 279                         } else {
 280                                 callback(
 281                                         PayloadCallbackAction::PushBack,
 282                                         msgs::OutboundOnionPayload::Receive {
 283                                                 payment_data: recipient_onion.payment_secret.map(|payment_secret| {
 284                                                         msgs::FinalOnionHopData { payment_secret, total_msat }
 285                                                 }),
 286                                                 payment_metadata: recipient_onion.payment_metadata.as_ref(),
 287                                                 keysend_preimage: *keysend_preimage,
 288                                                 custom_tlvs: &recipient_onion.custom_tlvs,
 289                                                 sender_intended_htlc_amt_msat: value_msat,
 290                                                 cltv_expiry_height: cltv,
 291                                         },
 292                                 );
 293                         }
 294                 } else {
 295                         let payload = msgs::OutboundOnionPayload::Forward {
 296                                 short_channel_id: last_short_channel_id,
 297                                 amt_to_forward: value_msat,
 298                                 outgoing_cltv_value: cltv,
 299                         };
 300                         callback(PayloadCallbackAction::PushFront, payload);
 301                 }
 302                 cur_value_msat += hop.fee_msat;
 303                 if cur_value_msat >= 21000000 * 100000000 * 1000 {
 304                         return Err(APIError::InvalidRoute { err: "Channel fees overflowed?".to_owned() });
 305                 }
 306                 cur_cltv += hop.cltv_expiry_delta as u32;
 307                 if cur_cltv >= 500000000 {
 308                         return Err(APIError::InvalidRoute { err: "Channel CLTV overflowed?".to_owned() });
 309                 }
 310                 last_short_channel_id = hop.short_channel_id;
 311         }
 312         Ok((cur_value_msat, cur_cltv))
 313 }
 314
 315 pub(crate) const MIN_FINAL_VALUE_ESTIMATE_WITH_OVERPAY: u64 = 100_000_000;
 316
 317 pub(crate) fn set_max_path_length(
 318         route_params: &mut RouteParameters, recipient_onion: &RecipientOnionFields,
 319         keysend_preimage: Option<PaymentPreimage>, best_block_height: u32,
 320 ) -> Result<(), ()> {
 321         const PAYLOAD_HMAC_LEN: usize = 32;
 322         let unblinded_intermed_payload_len = msgs::OutboundOnionPayload::Forward {
 323                 short_channel_id: 42,
 324                 amt_to_forward: TOTAL_BITCOIN_SUPPLY_SATOSHIS,
 325                 outgoing_cltv_value: route_params.payment_params.max_total_cltv_expiry_delta,
 326         }
 327         .serialized_length()
 328         .saturating_add(PAYLOAD_HMAC_LEN);
 329
 330         const OVERPAY_ESTIMATE_MULTIPLER: u64 = 3;
 331         let final_value_msat_with_overpay_buffer = core::cmp::max(
 332                 route_params.final_value_msat.saturating_mul(OVERPAY_ESTIMATE_MULTIPLER),
 333                 MIN_FINAL_VALUE_ESTIMATE_WITH_OVERPAY,
 334         );
 335
 336         let blinded_tail_opt = route_params
 337                 .payment_params
 338                 .payee
 339                 .blinded_route_hints()
 340                 .iter()
 341                 .map(|(_, path)| path)
 342                 .max_by_key(|path| path.serialized_length())
 343                 .map(|largest_path| BlindedTailHopIter {
 344                         hops: largest_path.blinded_hops.iter(),
 345                         blinding_point: largest_path.blinding_point,
 346                         final_value_msat: final_value_msat_with_overpay_buffer,
 347                         excess_final_cltv_expiry_delta: 0,
 348                 });
 349
 350         let unblinded_route_hop = RouteHop {
 351                 pubkey: PublicKey::from_slice(&[2; 33]).unwrap(),
 352                 node_features: NodeFeatures::empty(),
 353                 short_channel_id: 42,
 354                 channel_features: ChannelFeatures::empty(),
 355                 fee_msat: final_value_msat_with_overpay_buffer,
 356                 cltv_expiry_delta: route_params.payment_params.max_total_cltv_expiry_delta,
 357                 maybe_announced_channel: false,
 358         };
 359         let mut num_reserved_bytes: usize = 0;
 360         let build_payloads_res = build_onion_payloads_callback(
 361                 core::iter::once(&unblinded_route_hop),
 362                 blinded_tail_opt,
 363                 final_value_msat_with_overpay_buffer,
 364                 &recipient_onion,
 365                 best_block_height,
 366                 &keysend_preimage,
 367                 |_, payload| {
 368                         num_reserved_bytes = num_reserved_bytes
 369                                 .saturating_add(payload.serialized_length())
 370                                 .saturating_add(PAYLOAD_HMAC_LEN);
 371                 },
 372         );
 373         debug_assert!(build_payloads_res.is_ok());
 374
 375         let max_path_length = 1300usize
 376                 .checked_sub(num_reserved_bytes)
 377                 .map(|p| p / unblinded_intermed_payload_len)
 378                 .and_then(|l| u8::try_from(l.saturating_add(1)).ok())
 379                 .ok_or(())?;
 380
 381         route_params.payment_params.max_path_length =
 382                 core::cmp::min(max_path_length, route_params.payment_params.max_path_length);
 383         Ok(())
 384 }
 385
 386 /// Length of the onion data packet. Before TLV-based onions this was 20 65-byte hops, though now
 387 /// the hops can be of variable length.
 388 pub(crate) const ONION_DATA_LEN: usize = 20 * 65;
 389
 390 pub(super) const INVALID_ONION_BLINDING: u16 = 0x8000 | 0x4000 | 24;
 391
 392 #[inline]
 393 fn shift_slice_right(arr: &mut [u8], amt: usize) {
 394         for i in (amt..arr.len()).rev() {
 395                 arr[i] = arr[i - amt];
 396         }
 397         for i in 0..amt {
 398                 arr[i] = 0;
 399         }
 400 }
 401
 402 pub(super) fn construct_onion_packet(
 403         payloads: Vec<msgs::OutboundOnionPayload>, onion_keys: Vec<OnionKeys>, prng_seed: [u8; 32],
 404         associated_data: &PaymentHash,
 405 ) -> Result<msgs::OnionPacket, ()> {
 406         let mut packet_data = [0; ONION_DATA_LEN];
 407
 408         let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
 409         chacha.process(&[0; ONION_DATA_LEN], &mut packet_data);
 410
 411         let packet = FixedSizeOnionPacket(packet_data);
 412         construct_onion_packet_with_init_noise::<_, _>(
 413                 payloads,
 414                 onion_keys,
 415                 packet,
 416                 Some(associated_data),
 417         )
 418 }
 419
 420 #[allow(unused)]
 421 pub(super) fn construct_trampoline_onion_packet(
 422         payloads: Vec<msgs::OutboundTrampolinePayload>, onion_keys: Vec<OnionKeys>,
 423         prng_seed: [u8; 32], associated_data: &PaymentHash, length: u16,
 424 ) -> Result<msgs::TrampolineOnionPacket, ()> {
 425         let mut packet_data = vec![0u8; length as usize];
 426
 427         let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
 428         chacha.process(&vec![0u8; length as usize], &mut packet_data);
 429
 430         construct_onion_packet_with_init_noise::<_, _>(
 431                 payloads,
 432                 onion_keys,
 433                 packet_data,
 434                 Some(associated_data),
 435         )
 436 }
 437
 438 #[cfg(test)]
 439 /// Used in testing to write bogus `BogusOnionHopData` as well as `RawOnionHopData`, which is
 440 /// otherwise not representable in `msgs::OnionHopData`.
 441 pub(super) fn construct_onion_packet_with_writable_hopdata<HD: Writeable>(
 442         payloads: Vec<HD>, onion_keys: Vec<OnionKeys>, prng_seed: [u8; 32],
 443         associated_data: &PaymentHash,
 444 ) -> Result<msgs::OnionPacket, ()> {
 445         let mut packet_data = [0; ONION_DATA_LEN];
 446
 447         let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
 448         chacha.process(&[0; ONION_DATA_LEN], &mut packet_data);
 449
 450         let packet = FixedSizeOnionPacket(packet_data);
 451         construct_onion_packet_with_init_noise::<_, _>(
 452                 payloads,
 453                 onion_keys,
 454                 packet,
 455                 Some(associated_data),
 456         )
 457 }
 458
 459 /// Since onion message packets and onion payment packets have different lengths but are otherwise
 460 /// identical, we use this trait to allow `construct_onion_packet_with_init_noise` to return either
 461 /// type.
 462 pub(crate) trait Packet {
 463         type Data: AsMut<[u8]>;
 464         fn new(pubkey: PublicKey, hop_data: Self::Data, hmac: [u8; 32]) -> Self;
 465 }
 466
 467 // Needed for rustc versions older than 1.47 to avoid E0277: "arrays only have std trait
 468 // implementations for lengths 0..=32".
 469 pub(crate) struct FixedSizeOnionPacket(pub(crate) [u8; ONION_DATA_LEN]);
 470
 471 impl AsMut<[u8]> for FixedSizeOnionPacket {
 472         fn as_mut(&mut self) -> &mut [u8] {
 473                 &mut self.0
 474         }
 475 }
 476
 477 pub(crate) fn payloads_serialized_length<HD: Writeable>(payloads: &Vec<HD>) -> usize {
 478         payloads.iter().map(|p| p.serialized_length() + 32 /* HMAC */).sum()
 479 }
 480
 481 pub(crate) fn construct_onion_message_packet<HD: Writeable, P: Packet<Data = Vec<u8>>>(
 482         payloads: Vec<HD>, onion_keys: Vec<OnionKeys>, prng_seed: [u8; 32], packet_data_len: usize,
 483 ) -> Result<P, ()> {
 484         let mut packet_data = vec![0; packet_data_len];
 485
 486         let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
 487         chacha.process_in_place(&mut packet_data);
 488
 489         construct_onion_packet_with_init_noise::<_, _>(payloads, onion_keys, packet_data, None)
 490 }
 491
 492 fn construct_onion_packet_with_init_noise<HD: Writeable, P: Packet>(
 493         mut payloads: Vec<HD>, onion_keys: Vec<OnionKeys>, mut packet_data: P::Data,
 494         associated_data: Option<&PaymentHash>,
 495 ) -> Result<P, ()> {
 496         let filler = {
 497                 let packet_data = packet_data.as_mut();
 498                 const ONION_HOP_DATA_LEN: usize = 65; // We may decrease this eventually after TLV is common
 499                 let mut res = Vec::with_capacity(ONION_HOP_DATA_LEN * (payloads.len() - 1));
 500
 501                 let mut pos = 0;
 502                 for (i, (payload, keys)) in payloads.iter().zip(onion_keys.iter()).enumerate() {
 503                         let mut chacha = ChaCha20::new(&keys.rho, &[0u8; 8]);
 504                         // TODO: Batch this.
 505                         for _ in 0..(packet_data.len() - pos) {
 506                                 let mut dummy = [0; 1];
 507                                 chacha.process_in_place(&mut dummy); // We don't have a seek function :(
 508                         }
 509
 510                         let mut payload_len = LengthCalculatingWriter(0);
 511                         payload.write(&mut payload_len).expect("Failed to calculate length");
 512                         pos += payload_len.0 + 32;
 513                         if pos > packet_data.len() {
 514                                 return Err(());
 515                         }
 516
 517                         if i == payloads.len() - 1 {
 518                                 break;
 519                         }
 520
 521                         res.resize(pos, 0u8);
 522                         chacha.process_in_place(&mut res);
 523                 }
 524                 res
 525         };
 526
 527         let mut hmac_res = [0; 32];
 528         for (i, (payload, keys)) in payloads.iter_mut().zip(onion_keys.iter()).rev().enumerate() {
 529                 let mut payload_len = LengthCalculatingWriter(0);
 530                 payload.write(&mut payload_len).expect("Failed to calculate length");
 531
 532                 let packet_data = packet_data.as_mut();
 533                 shift_slice_right(packet_data, payload_len.0 + 32);
 534                 packet_data[0..payload_len.0].copy_from_slice(&payload.encode()[..]);
 535                 packet_data[payload_len.0..(payload_len.0 + 32)].copy_from_slice(&hmac_res);
 536
 537                 let mut chacha = ChaCha20::new(&keys.rho, &[0u8; 8]);
 538                 chacha.process_in_place(packet_data);
 539
 540                 if i == 0 {
 541                         let stop_index = packet_data.len();
 542                         let start_index = stop_index.checked_sub(filler.len()).ok_or(())?;
 543                         packet_data[start_index..stop_index].copy_from_slice(&filler[..]);
 544                 }
 545
 546                 let mut hmac = HmacEngine::<Sha256>::new(&keys.mu);
 547                 hmac.input(packet_data);
 548                 if let Some(associated_data) = associated_data {
 549                         hmac.input(&associated_data.0[..]);
 550                 }
 551                 hmac_res = Hmac::from_engine(hmac).to_byte_array();
 552         }
 553
 554         Ok(P::new(onion_keys.first().unwrap().ephemeral_pubkey, packet_data, hmac_res))
 555 }
 556
 557 /// Encrypts a failure packet. raw_packet can either be a
 558 /// msgs::DecodedOnionErrorPacket.encode() result or a msgs::OnionErrorPacket.data element.
 559 pub(super) fn encrypt_failure_packet(
 560         shared_secret: &[u8], raw_packet: &[u8],
 561 ) -> msgs::OnionErrorPacket {
 562         let ammag = gen_ammag_from_shared_secret(&shared_secret);
 563
 564         let mut packet_crypted = Vec::with_capacity(raw_packet.len());
 565         packet_crypted.resize(raw_packet.len(), 0);
 566         let mut chacha = ChaCha20::new(&ammag, &[0u8; 8]);
 567         chacha.process(&raw_packet, &mut packet_crypted[..]);
 568         msgs::OnionErrorPacket { data: packet_crypted }
 569 }
 570
 571 pub(super) fn build_failure_packet(
 572         shared_secret: &[u8], failure_type: u16, failure_data: &[u8],
 573 ) -> msgs::DecodedOnionErrorPacket {
 574         assert_eq!(shared_secret.len(), 32);
 575         assert!(failure_data.len() <= 256 - 2);
 576
 577         let um = gen_um_from_shared_secret(&shared_secret);
 578
 579         let failuremsg = {
 580                 let mut res = Vec::with_capacity(2 + failure_data.len());
 581                 res.push(((failure_type >> 8) & 0xff) as u8);
 582                 res.push(((failure_type >> 0) & 0xff) as u8);
 583                 res.extend_from_slice(&failure_data[..]);
 584                 res
 585         };
 586         let pad = {
 587                 let mut res = Vec::with_capacity(256 - 2 - failure_data.len());
 588                 res.resize(256 - 2 - failure_data.len(), 0);
 589                 res
 590         };
 591         let mut packet = msgs::DecodedOnionErrorPacket { hmac: [0; 32], failuremsg, pad };
 592
 593         let mut hmac = HmacEngine::<Sha256>::new(&um);
 594         hmac.input(&packet.encode()[32..]);
 595         packet.hmac = Hmac::from_engine(hmac).to_byte_array();
 596
 597         packet
 598 }
 599
 600 #[cfg(test)]
 601 pub(super) fn build_first_hop_failure_packet(
 602         shared_secret: &[u8], failure_type: u16, failure_data: &[u8],
 603 ) -> msgs::OnionErrorPacket {
 604         let failure_packet = build_failure_packet(shared_secret, failure_type, failure_data);
 605         encrypt_failure_packet(shared_secret, &failure_packet.encode()[..])
 606 }
 607
 608 pub(crate) struct DecodedOnionFailure {
 609         pub(crate) network_update: Option<NetworkUpdate>,
 610         pub(crate) short_channel_id: Option<u64>,
 611         pub(crate) payment_failed_permanently: bool,
 612         pub(crate) failed_within_blinded_path: bool,
 613         #[cfg(test)]
 614         pub(crate) onion_error_code: Option<u16>,
 615         #[cfg(test)]
 616         pub(crate) onion_error_data: Option<Vec<u8>>,
 617 }
 618
 619 /// Note that we always decrypt `packet` in-place here even if the deserialization into
 620 /// [`msgs::DecodedOnionErrorPacket`] ultimately fails.
 621 fn decrypt_onion_error_packet(
 622         packet: &mut Vec<u8>, shared_secret: SharedSecret,
 623 ) -> Result<msgs::DecodedOnionErrorPacket, msgs::DecodeError> {
 624         let ammag = gen_ammag_from_shared_secret(shared_secret.as_ref());
 625         let mut chacha = ChaCha20::new(&ammag, &[0u8; 8]);
 626         chacha.process_in_place(packet);
 627         msgs::DecodedOnionErrorPacket::read(&mut Cursor::new(packet))
 628 }
 629
 630 /// Process failure we got back from upstream on a payment we sent (implying htlc_source is an
 631 /// OutboundRoute).
 632 #[inline]
 633 pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
 634         secp_ctx: &Secp256k1<T>, logger: &L, htlc_source: &HTLCSource, mut encrypted_packet: Vec<u8>,
 635 ) -> DecodedOnionFailure
 636 where
 637         L::Target: Logger,
 638 {
 639         let (path, session_priv, first_hop_htlc_msat) = match htlc_source {
 640                 HTLCSource::OutboundRoute {
 641                         ref path, ref session_priv, ref first_hop_htlc_msat, ..
 642                 } => (path, session_priv, first_hop_htlc_msat),
 643                 _ => {
 644                         unreachable!()
 645                 },
 646         };
 647
 648         // Learnings from the HTLC failure to inform future payment retries and scoring.
 649         struct FailureLearnings {
 650                 network_update: Option<NetworkUpdate>,
 651                 short_channel_id: Option<u64>,
 652                 payment_failed_permanently: bool,
 653                 failed_within_blinded_path: bool,
 654         }
 655         let mut res: Option<FailureLearnings> = None;
 656         let mut htlc_msat = *first_hop_htlc_msat;
 657         let mut error_code_ret = None;
 658         let mut error_packet_ret = None;
 659         let mut is_from_final_node = false;
 660
 661         const BADONION: u16 = 0x8000;
 662         const PERM: u16 = 0x4000;
 663         const NODE: u16 = 0x2000;
 664         const UPDATE: u16 = 0x1000;
 665
 666         // Handle packed channel/node updates for passing back for the route handler
 667         let callback = |shared_secret, _, _, route_hop_opt: Option<&RouteHop>, route_hop_idx| {
 668                 if res.is_some() {
 669                         return;
 670                 }
 671
 672                 let route_hop = match route_hop_opt {
 673                         Some(hop) => hop,
 674                         None => {
 675                                 // Got an error from within a blinded route.
 676                                 error_code_ret = Some(BADONION | PERM | 24); // invalid_onion_blinding
 677                                 error_packet_ret = Some(vec![0; 32]);
 678                                 res = Some(FailureLearnings {
 679                                         network_update: None,
 680                                         short_channel_id: None,
 681                                         payment_failed_permanently: false,
 682                                         failed_within_blinded_path: true,
 683                                 });
 684                                 return;
 685                         },
 686                 };
 687
 688                 // The failing hop includes either the inbound channel to the recipient or the outbound channel
 689                 // from the current hop (i.e., the next hop's inbound channel).
 690                 let num_blinded_hops = path.blinded_tail.as_ref().map_or(0, |bt| bt.hops.len());
 691                 // For 1-hop blinded paths, the final `path.hops` entry is the recipient.
 692                 is_from_final_node = route_hop_idx + 1 == path.hops.len() && num_blinded_hops <= 1;
 693                 let failing_route_hop = if is_from_final_node {
 694                         route_hop
 695                 } else {
 696                         match path.hops.get(route_hop_idx + 1) {
 697                                 Some(hop) => hop,
 698                                 None => {
 699                                         // The failing hop is within a multi-hop blinded path.
 700                                         #[cfg(not(test))]
 701                                         {
 702                                                 error_code_ret = Some(BADONION | PERM | 24); // invalid_onion_blinding
 703                                                 error_packet_ret = Some(vec![0; 32]);
 704                                         }
 705                                         #[cfg(test)]
 706                                         {
 707                                                 // Actually parse the onion error data in tests so we can check that blinded hops fail
 708                                                 // back correctly.
 709                                                 let err_packet =
 710                                                         decrypt_onion_error_packet(&mut encrypted_packet, shared_secret)
 711                                                                 .unwrap();
 712                                                 error_code_ret = Some(u16::from_be_bytes(
 713                                                         err_packet.failuremsg.get(0..2).unwrap().try_into().unwrap(),
 714                                                 ));
 715                                                 error_packet_ret = Some(err_packet.failuremsg[2..].to_vec());
 716                                         }
 717
 718                                         res = Some(FailureLearnings {
 719                                                 network_update: None,
 720                                                 short_channel_id: None,
 721                                                 payment_failed_permanently: false,
 722                                                 failed_within_blinded_path: true,
 723                                         });
 724                                         return;
 725                                 },
 726                         }
 727                 };
 728
 729                 let amt_to_forward = htlc_msat - route_hop.fee_msat;
 730                 htlc_msat = amt_to_forward;
 731
 732                 let err_packet = match decrypt_onion_error_packet(&mut encrypted_packet, shared_secret) {
 733                         Ok(p) => p,
 734                         Err(_) => return,
 735                 };
 736                 let um = gen_um_from_shared_secret(shared_secret.as_ref());
 737                 let mut hmac = HmacEngine::<Sha256>::new(&um);
 738                 hmac.input(&err_packet.encode()[32..]);
 739
 740                 if !fixed_time_eq(&Hmac::from_engine(hmac).to_byte_array(), &err_packet.hmac) {
 741                         return;
 742                 }
 743                 let error_code_slice = match err_packet.failuremsg.get(0..2) {
 744                         Some(s) => s,
 745                         None => {
 746                                 // Useless packet that we can't use but it passed HMAC, so it definitely came from the peer
 747                                 // in question
 748                                 let network_update = Some(NetworkUpdate::NodeFailure {
 749                                         node_id: route_hop.pubkey,
 750                                         is_permanent: true,
 751                                 });
 752                                 let short_channel_id = Some(route_hop.short_channel_id);
 753                                 res = Some(FailureLearnings {
 754                                         network_update,
 755                                         short_channel_id,
 756                                         payment_failed_permanently: is_from_final_node,
 757                                         failed_within_blinded_path: false,
 758                                 });
 759                                 return;
 760                         },
 761                 };
 762
 763                 let error_code = u16::from_be_bytes(error_code_slice.try_into().expect("len is 2"));
 764                 error_code_ret = Some(error_code);
 765                 error_packet_ret = Some(err_packet.failuremsg[2..].to_vec());
 766
 767                 let (debug_field, debug_field_size) = errors::get_onion_debug_field(error_code);
 768
 769                 // indicate that payment parameter has failed and no need to update Route object
 770                 let payment_failed = match error_code & 0xff {
 771                         15 | 16 | 17 | 18 | 19 | 23 => true,
 772                         _ => false,
 773                 } && is_from_final_node; // PERM bit observed below even if this error is from the intermediate nodes
 774
 775                 let mut network_update = None;
 776                 let mut short_channel_id = None;
 777
 778                 if error_code & BADONION == BADONION {
 779                         // If the error code has the BADONION bit set, always blame the channel from the node
 780                         // "originating" the error to its next hop. The "originator" is ultimately actually claiming
 781                         // that its counterparty is the one who is failing the HTLC.
 782                         // If the "originator" here isn't lying we should really mark the next-hop node as failed
 783                         // entirely, but we can't be confident in that, as it would allow any node to get us to
 784                         // completely ban one of its counterparties. Instead, we simply remove the channel in
 785                         // question.
 786                         network_update = Some(NetworkUpdate::ChannelFailure {
 787                                 short_channel_id: failing_route_hop.short_channel_id,
 788                                 is_permanent: true,
 789                         });
 790                 } else if error_code & NODE == NODE {
 791                         let is_permanent = error_code & PERM == PERM;
 792                         network_update =
 793                                 Some(NetworkUpdate::NodeFailure { node_id: route_hop.pubkey, is_permanent });
 794                         short_channel_id = Some(route_hop.short_channel_id);
 795                 } else if error_code & PERM == PERM {
 796                         if !payment_failed {
 797                                 network_update = Some(NetworkUpdate::ChannelFailure {
 798                                         short_channel_id: failing_route_hop.short_channel_id,
 799                                         is_permanent: true,
 800                                 });
 801                                 short_channel_id = Some(failing_route_hop.short_channel_id);
 802                         }
 803                 } else if error_code & UPDATE == UPDATE {
 804                         if let Some(update_len_slice) =
 805                                 err_packet.failuremsg.get(debug_field_size + 2..debug_field_size + 4)
 806                         {
 807                                 let update_len =
 808                                         u16::from_be_bytes(update_len_slice.try_into().expect("len is 2")) as usize;
 809                                 if let Some(mut update_slice) = err_packet
 810                                         .failuremsg
 811                                         .get(debug_field_size + 4..debug_field_size + 4 + update_len)
 812                                 {
 813                                         // Historically, the BOLTs were unclear if the message type
 814                                         // bytes should be included here or not. The BOLTs have now
 815                                         // been updated to indicate that they *are* included, but many
 816                                         // nodes still send messages without the type bytes, so we
 817                                         // support both here.
 818                                         // TODO: Switch to hard require the type prefix, as the current
 819                                         // permissiveness introduces the (although small) possibility
 820                                         // that we fail to decode legitimate channel updates that
 821                                         // happen to start with ChannelUpdate::TYPE, i.e., [0x01, 0x02].
 822                                         if update_slice.len() > 2
 823                                                 && update_slice[0..2] == msgs::ChannelUpdate::TYPE.to_be_bytes()
 824                                         {
 825                                                 update_slice = &update_slice[2..];
 826                                         } else {
 827                                                 log_trace!(logger, "Failure provided features a channel update without type prefix. Deprecated, but allowing for now.");
 828                                         }
 829                                         let update_opt = msgs::ChannelUpdate::read(&mut Cursor::new(&update_slice));
 830                                         if update_opt.is_ok() || update_slice.is_empty() {
 831                                                 // if channel_update should NOT have caused the failure:
 832                                                 // MAY treat the channel_update as invalid.
 833                                                 let is_chan_update_invalid = match error_code & 0xff {
 834                                                         7 => false,
 835                                                         11 => {
 836                                                                 update_opt.is_ok()
 837                                                                         && amt_to_forward
 838                                                                                 > update_opt.as_ref().unwrap().contents.htlc_minimum_msat
 839                                                         },
 840                                                         12 => {
 841                                                                 update_opt.is_ok()
 842                                                                         && amt_to_forward
 843                                                                                 .checked_mul(
 844                                                                                         update_opt
 845                                                                                                 .as_ref()
 846                                                                                                 .unwrap()
 847                                                                                                 .contents
 848                                                                                                 .fee_proportional_millionths as u64,
 849                                                                                 )
 850                                                                                 .map(|prop_fee| prop_fee / 1_000_000)
 851                                                                                 .and_then(|prop_fee| {
 852                                                                                         prop_fee.checked_add(
 853                                                                                                 update_opt.as_ref().unwrap().contents.fee_base_msat
 854                                                                                                         as u64,
 855                                                                                         )
 856                                                                                 })
 857                                                                                 .map(|fee_msats| route_hop.fee_msat >= fee_msats)
 858                                                                                 .unwrap_or(false)
 859                                                         },
 860                                                         13 => {
 861                                                                 update_opt.is_ok()
 862                                                                         && route_hop.cltv_expiry_delta as u16
 863                                                                                 >= update_opt.as_ref().unwrap().contents.cltv_expiry_delta
 864                                                         },
 865                                                         14 => false, // expiry_too_soon; always valid?
 866                                                         20 => update_opt.as_ref().unwrap().contents.flags & 2 == 0,
 867                                                         _ => false, // unknown error code; take channel_update as valid
 868                                                 };
 869                                                 if is_chan_update_invalid {
 870                                                         // This probably indicates the node which forwarded
 871                                                         // to the node in question corrupted something.
 872                                                         network_update = Some(NetworkUpdate::ChannelFailure {
 873                                                                 short_channel_id: route_hop.short_channel_id,
 874                                                                 is_permanent: true,
 875                                                         });
 876                                                 } else {
 877                                                         if let Ok(chan_update) = update_opt {
 878                                                                 // Make sure the ChannelUpdate contains the expected
 879                                                                 // short channel id.
 880                                                                 if failing_route_hop.short_channel_id
 881                                                                         == chan_update.contents.short_channel_id
 882                                                                 {
 883                                                                         short_channel_id = Some(failing_route_hop.short_channel_id);
 884                                                                 } else {
 885                                                                         log_info!(logger, "Node provided a channel_update for which it was not authoritative, ignoring.");
 886                                                                 }
 887                                                                 network_update =
 888                                                                         Some(NetworkUpdate::ChannelUpdateMessage { msg: chan_update })
 889                                                         } else {
 890                                                                 // The node in question intentionally encoded a 0-length channel update. This is
 891                                                                 // likely due to https://github.com/ElementsProject/lightning/issues/6200.
 892                                                                 short_channel_id = Some(failing_route_hop.short_channel_id);
 893                                                                 network_update = Some(NetworkUpdate::ChannelFailure {
 894                                                                         short_channel_id: failing_route_hop.short_channel_id,
 895                                                                         is_permanent: false,
 896                                                                 });
 897                                                         }
 898                                                 };
 899                                         } else {
 900                                                 // If the channel_update had a non-zero length (i.e. was
 901                                                 // present) but we couldn't read it, treat it as a total
 902                                                 // node failure.
 903                                                 log_info!(
 904                                                         logger,
 905                                                         "Failed to read a channel_update of len {} in an onion",
 906                                                         update_slice.len()
 907                                                 );
 908                                         }
 909                                 }
 910                         }
 911                         if network_update.is_none() {
 912                                 // They provided an UPDATE which was obviously bogus, not worth
 913                                 // trying to relay through them anymore.
 914                                 network_update = Some(NetworkUpdate::NodeFailure {
 915                                         node_id: route_hop.pubkey,
 916                                         is_permanent: true,
 917                                 });
 918                         }
 919                         if short_channel_id.is_none() {
 920                                 short_channel_id = Some(route_hop.short_channel_id);
 921                         }
 922                 } else if payment_failed {
 923                         // Only blame the hop when a value in the HTLC doesn't match the corresponding value in the
 924                         // onion.
 925                         short_channel_id = match error_code & 0xff {
 926                                 18 | 19 => Some(route_hop.short_channel_id),
 927                                 _ => None,
 928                         };
 929                 } else {
 930                         // We can't understand their error messages and they failed to forward...they probably can't
 931                         // understand our forwards so it's really not worth trying any further.
 932                         network_update =
 933                                 Some(NetworkUpdate::NodeFailure { node_id: route_hop.pubkey, is_permanent: true });
 934                         short_channel_id = Some(route_hop.short_channel_id);
 935                 }
 936
 937                 res = Some(FailureLearnings {
 938                         network_update,
 939                         short_channel_id,
 940                         payment_failed_permanently: error_code & PERM == PERM && is_from_final_node,
 941                         failed_within_blinded_path: false,
 942                 });
 943
 944                 let (description, title) = errors::get_onion_error_description(error_code);
 945                 if debug_field_size > 0 && err_packet.failuremsg.len() >= 4 + debug_field_size {
 946                         log_info!(
 947                                 logger,
 948                                 "Onion Error[from {}: {}({:#x}) {}({})] {}",
 949                                 route_hop.pubkey,
 950                                 title,
 951                                 error_code,
 952                                 debug_field,
 953                                 log_bytes!(&err_packet.failuremsg[4..4 + debug_field_size]),
 954                                 description
 955                         );
 956                 } else {
 957                         log_info!(
 958                                 logger,
 959                                 "Onion Error[from {}: {}({:#x})] {}",
 960                                 route_hop.pubkey,
 961                                 title,
 962                                 error_code,
 963                                 description
 964                         );
 965                 }
 966         };
 967
 968         construct_onion_keys_callback(secp_ctx, &path, session_priv, callback)
 969                 .expect("Route that we sent via spontaneously grew invalid keys in the middle of it?");
 970
 971         if let Some(FailureLearnings {
 972                 network_update,
 973                 short_channel_id,
 974                 payment_failed_permanently,
 975                 failed_within_blinded_path,
 976         }) = res
 977         {
 978                 DecodedOnionFailure {
 979                         network_update,
 980                         short_channel_id,
 981                         payment_failed_permanently,
 982                         failed_within_blinded_path,
 983                         #[cfg(test)]
 984                         onion_error_code: error_code_ret,
 985                         #[cfg(test)]
 986                         onion_error_data: error_packet_ret,
 987                 }
 988         } else {
 989                 // only not set either packet unparseable or hmac does not match with any
 990                 // payment not retryable only when garbage is from the final node
 991                 DecodedOnionFailure {
 992                         network_update: None,
 993                         short_channel_id: None,
 994                         payment_failed_permanently: is_from_final_node,
 995                         failed_within_blinded_path: false,
 996                         #[cfg(test)]
 997                         onion_error_code: None,
 998                         #[cfg(test)]
 999                         onion_error_data: None,
1000                 }
1001         }
1002 }
1003
1004 #[derive(Clone)] // See Channel::revoke_and_ack for why, tl;dr: Rust bug
1005 #[cfg_attr(test, derive(PartialEq))]
1006 pub(super) struct HTLCFailReason(HTLCFailReasonRepr);
1007
1008 #[derive(Clone)] // See Channel::revoke_and_ack for why, tl;dr: Rust bug
1009 #[cfg_attr(test, derive(PartialEq))]
1010 enum HTLCFailReasonRepr {
1011         LightningError { err: msgs::OnionErrorPacket },
1012         Reason { failure_code: u16, data: Vec<u8> },
1013 }
1014
1015 impl core::fmt::Debug for HTLCFailReason {
1016         fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
1017                 match self.0 {
1018                         HTLCFailReasonRepr::Reason { ref failure_code, .. } => {
1019                                 write!(f, "HTLC error code {}", failure_code)
1020                         },
1021                         HTLCFailReasonRepr::LightningError { .. } => {
1022                                 write!(f, "pre-built LightningError")
1023                         },
1024                 }
1025         }
1026 }
1027
1028 impl Writeable for HTLCFailReason {
1029         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), crate::io::Error> {
1030                 self.0.write(writer)
1031         }
1032 }
1033 impl Readable for HTLCFailReason {
1034         fn read<R: Read>(reader: &mut R) -> Result<Self, msgs::DecodeError> {
1035                 Ok(Self(Readable::read(reader)?))
1036         }
1037 }
1038
1039 impl_writeable_tlv_based_enum!(HTLCFailReasonRepr,
1040         (0, LightningError) => {
1041                 (0, err, required),
1042         },
1043         (1, Reason) => {
1044                 (0, failure_code, required),
1045                 (2, data, required_vec),
1046         },
1047 ;);
1048
1049 impl HTLCFailReason {
1050         #[rustfmt::skip]
1051         pub(super) fn reason(failure_code: u16, data: Vec<u8>) -> Self {
1052                 const BADONION: u16 = 0x8000;
1053                 const PERM: u16 = 0x4000;
1054                 const NODE: u16 = 0x2000;
1055                 const UPDATE: u16 = 0x1000;
1056
1057                      if failure_code == 1  | PERM { debug_assert!(data.is_empty()) }
1058                 else if failure_code == 2  | NODE { debug_assert!(data.is_empty()) }
1059                 else if failure_code == 2  | PERM | NODE { debug_assert!(data.is_empty()) }
1060                 else if failure_code == 3  | PERM | NODE { debug_assert!(data.is_empty()) }
1061                 else if failure_code == 4  | BADONION | PERM { debug_assert_eq!(data.len(), 32) }
1062                 else if failure_code == 5  | BADONION | PERM { debug_assert_eq!(data.len(), 32) }
1063                 else if failure_code == 6  | BADONION | PERM { debug_assert_eq!(data.len(), 32) }
1064                 else if failure_code == 7  | UPDATE {
1065                         debug_assert_eq!(data.len() - 2, u16::from_be_bytes(data[0..2].try_into().unwrap()) as usize) }
1066                 else if failure_code == 8  | PERM { debug_assert!(data.is_empty()) }
1067                 else if failure_code == 9  | PERM { debug_assert!(data.is_empty()) }
1068                 else if failure_code == 10 | PERM { debug_assert!(data.is_empty()) }
1069                 else if failure_code == 11 | UPDATE {
1070                         debug_assert_eq!(data.len() - 2 - 8, u16::from_be_bytes(data[8..10].try_into().unwrap()) as usize) }
1071                 else if failure_code == 12 | UPDATE {
1072                         debug_assert_eq!(data.len() - 2 - 8, u16::from_be_bytes(data[8..10].try_into().unwrap()) as usize) }
1073                 else if failure_code == 13 | UPDATE {
1074                         debug_assert_eq!(data.len() - 2 - 4, u16::from_be_bytes(data[4..6].try_into().unwrap()) as usize) }
1075                 else if failure_code == 14 | UPDATE {
1076                         debug_assert_eq!(data.len() - 2, u16::from_be_bytes(data[0..2].try_into().unwrap()) as usize) }
1077                 else if failure_code == 15 | PERM { debug_assert_eq!(data.len(), 12) }
1078                 else if failure_code == 18 { debug_assert_eq!(data.len(), 4) }
1079                 else if failure_code == 19 { debug_assert_eq!(data.len(), 8) }
1080                 else if failure_code == 20 | UPDATE {
1081                         debug_assert_eq!(data.len() - 2 - 2, u16::from_be_bytes(data[2..4].try_into().unwrap()) as usize) }
1082                 else if failure_code == 21 { debug_assert!(data.is_empty()) }
1083                 else if failure_code == 22 | PERM { debug_assert!(data.len() <= 11) }
1084                 else if failure_code == 23 { debug_assert!(data.is_empty()) }
1085                 else if failure_code & BADONION != 0 {
1086                         // We set some bogus BADONION failure codes in test, so ignore unknown ones.
1087                 }
1088                 else { debug_assert!(false, "Unknown failure code: {}", failure_code) }
1089
1090                 Self(HTLCFailReasonRepr::Reason { failure_code, data })
1091         }
1092
1093         pub(super) fn from_failure_code(failure_code: u16) -> Self {
1094                 Self::reason(failure_code, Vec::new())
1095         }
1096
1097         pub(super) fn from_msg(msg: &msgs::UpdateFailHTLC) -> Self {
1098                 Self(HTLCFailReasonRepr::LightningError { err: msg.reason.clone() })
1099         }
1100
1101         pub(super) fn get_encrypted_failure_packet(
1102                 &self, incoming_packet_shared_secret: &[u8; 32], phantom_shared_secret: &Option<[u8; 32]>,
1103         ) -> msgs::OnionErrorPacket {
1104                 match self.0 {
1105                         HTLCFailReasonRepr::Reason { ref failure_code, ref data } => {
1106                                 if let Some(phantom_ss) = phantom_shared_secret {
1107                                         let phantom_packet =
1108                                                 build_failure_packet(phantom_ss, *failure_code, &data[..]).encode();
1109                                         let encrypted_phantom_packet =
1110                                                 encrypt_failure_packet(phantom_ss, &phantom_packet);
1111                                         encrypt_failure_packet(
1112                                                 incoming_packet_shared_secret,
1113                                                 &encrypted_phantom_packet.data[..],
1114                                         )
1115                                 } else {
1116                                         let packet = build_failure_packet(
1117                                                 incoming_packet_shared_secret,
1118                                                 *failure_code,
1119                                                 &data[..],
1120                                         )
1121                                         .encode();
1122                                         encrypt_failure_packet(incoming_packet_shared_secret, &packet)
1123                                 }
1124                         },
1125                         HTLCFailReasonRepr::LightningError { ref err } => {
1126                                 encrypt_failure_packet(incoming_packet_shared_secret, &err.data)
1127                         },
1128                 }
1129         }
1130
1131         pub(super) fn decode_onion_failure<T: secp256k1::Signing, L: Deref>(
1132                 &self, secp_ctx: &Secp256k1<T>, logger: &L, htlc_source: &HTLCSource,
1133         ) -> DecodedOnionFailure
1134         where
1135                 L::Target: Logger,
1136         {
1137                 match self.0 {
1138                         HTLCFailReasonRepr::LightningError { ref err } => {
1139                                 process_onion_failure(secp_ctx, logger, &htlc_source, err.data.clone())
1140                         },
1141                         #[allow(unused)]
1142                         HTLCFailReasonRepr::Reason { ref failure_code, ref data, .. } => {
1143                                 // we get a fail_malformed_htlc from the first hop
1144                                 // TODO: We'd like to generate a NetworkUpdate for temporary
1145                                 // failures here, but that would be insufficient as find_route
1146                                 // generally ignores its view of our own channels as we provide them via
1147                                 // ChannelDetails.
1148                                 if let &HTLCSource::OutboundRoute { ref path, .. } = htlc_source {
1149                                         DecodedOnionFailure {
1150                                                 network_update: None,
1151                                                 payment_failed_permanently: false,
1152                                                 short_channel_id: Some(path.hops[0].short_channel_id),
1153                                                 failed_within_blinded_path: false,
1154                                                 #[cfg(test)]
1155                                                 onion_error_code: Some(*failure_code),
1156                                                 #[cfg(test)]
1157                                                 onion_error_data: Some(data.clone()),
1158                                         }
1159                                 } else {
1160                                         unreachable!();
1161                                 }
1162                         },
1163                 }
1164         }
1165 }
1166
1167 /// Allows `decode_next_hop` to return the next hop packet bytes for either payments or onion
1168 /// message forwards.
1169 pub(crate) trait NextPacketBytes: AsMut<[u8]> {
1170         fn new(len: usize) -> Self;
1171 }
1172
1173 impl NextPacketBytes for FixedSizeOnionPacket {
1174         fn new(_len: usize) -> Self {
1175                 Self([0 as u8; ONION_DATA_LEN])
1176         }
1177 }
1178
1179 impl NextPacketBytes for Vec<u8> {
1180         fn new(len: usize) -> Self {
1181                 vec![0 as u8; len]
1182         }
1183 }
1184
1185 /// Data decrypted from a payment's onion payload.
1186 pub(crate) enum Hop {
1187         /// This onion payload was for us, not for forwarding to a next-hop. Contains information for
1188         /// verifying the incoming payment.
1189         Receive(msgs::InboundOnionPayload),
1190         /// This onion payload needs to be forwarded to a next-hop.
1191         Forward {
1192                 /// Onion payload data used in forwarding the payment.
1193                 next_hop_data: msgs::InboundOnionPayload,
1194                 /// HMAC of the next hop's onion packet.
1195                 next_hop_hmac: [u8; 32],
1196                 /// Bytes of the onion packet we're forwarding.
1197                 new_packet_bytes: [u8; ONION_DATA_LEN],
1198         },
1199 }
1200
1201 impl Hop {
1202         pub(crate) fn is_intro_node_blinded_forward(&self) -> bool {
1203                 match self {
1204                         Self::Forward {
1205                                 next_hop_data:
1206                                         msgs::InboundOnionPayload::BlindedForward {
1207                                                 intro_node_blinding_point: Some(_), ..
1208                                         },
1209                                 ..
1210                         } => true,
1211                         _ => false,
1212                 }
1213         }
1214 }
1215
1216 /// Error returned when we fail to decode the onion packet.
1217 #[derive(Debug)]
1218 pub(crate) enum OnionDecodeErr {
1219         /// The HMAC of the onion packet did not match the hop data.
1220         Malformed { err_msg: &'static str, err_code: u16 },
1221         /// We failed to decode the onion payload.
1222         Relay { err_msg: &'static str, err_code: u16 },
1223 }
1224
1225 pub(crate) fn decode_next_payment_hop<NS: Deref>(
1226         shared_secret: [u8; 32], hop_data: &[u8], hmac_bytes: [u8; 32], payment_hash: PaymentHash,
1227         blinding_point: Option<PublicKey>, node_signer: &NS,
1228 ) -> Result<Hop, OnionDecodeErr>
1229 where
1230         NS::Target: NodeSigner,
1231 {
1232         match decode_next_hop(
1233                 shared_secret,
1234                 hop_data,
1235                 hmac_bytes,
1236                 Some(payment_hash),
1237                 (blinding_point, node_signer),
1238         ) {
1239                 Ok((next_hop_data, None)) => Ok(Hop::Receive(next_hop_data)),
1240                 Ok((next_hop_data, Some((next_hop_hmac, FixedSizeOnionPacket(new_packet_bytes))))) => {
1241                         Ok(Hop::Forward { next_hop_data, next_hop_hmac, new_packet_bytes })
1242                 },
1243                 Err(e) => Err(e),
1244         }
1245 }
1246
1247 /// Build a payment onion, returning the first hop msat and cltv values as well.
1248 /// `cur_block_height` should be set to the best known block height + 1.
1249 pub fn create_payment_onion<T: secp256k1::Signing>(
1250         secp_ctx: &Secp256k1<T>, path: &Path, session_priv: &SecretKey, total_msat: u64,
1251         recipient_onion: &RecipientOnionFields, cur_block_height: u32, payment_hash: &PaymentHash,
1252         keysend_preimage: &Option<PaymentPreimage>, prng_seed: [u8; 32],
1253 ) -> Result<(msgs::OnionPacket, u64, u32), APIError> {
1254         let onion_keys = construct_onion_keys(&secp_ctx, &path, &session_priv).map_err(|_| {
1255                 APIError::InvalidRoute { err: "Pubkey along hop was maliciously selected".to_owned() }
1256         })?;
1257         let (onion_payloads, htlc_msat, htlc_cltv) = build_onion_payloads(
1258                 &path,
1259                 total_msat,
1260                 recipient_onion,
1261                 cur_block_height,
1262                 keysend_preimage,
1263         )?;
1264         let onion_packet = construct_onion_packet(onion_payloads, onion_keys, prng_seed, payment_hash)
1265                 .map_err(|_| APIError::InvalidRoute {
1266                         err: "Route size too large considering onion data".to_owned(),
1267                 })?;
1268         Ok((onion_packet, htlc_msat, htlc_cltv))
1269 }
1270
1271 pub(crate) fn decode_next_untagged_hop<T, R: ReadableArgs<T>, N: NextPacketBytes>(
1272         shared_secret: [u8; 32], hop_data: &[u8], hmac_bytes: [u8; 32], read_args: T,
1273 ) -> Result<(R, Option<([u8; 32], N)>), OnionDecodeErr> {
1274         decode_next_hop(shared_secret, hop_data, hmac_bytes, None, read_args)
1275 }
1276
1277 fn decode_next_hop<T, R: ReadableArgs<T>, N: NextPacketBytes>(
1278         shared_secret: [u8; 32], hop_data: &[u8], hmac_bytes: [u8; 32],
1279         payment_hash: Option<PaymentHash>, read_args: T,
1280 ) -> Result<(R, Option<([u8; 32], N)>), OnionDecodeErr> {
1281         let (rho, mu) = gen_rho_mu_from_shared_secret(&shared_secret);
1282         let mut hmac = HmacEngine::<Sha256>::new(&mu);
1283         hmac.input(hop_data);
1284         if let Some(tag) = payment_hash {
1285                 hmac.input(&tag.0[..]);
1286         }
1287         if !fixed_time_eq(&Hmac::from_engine(hmac).to_byte_array(), &hmac_bytes) {
1288                 return Err(OnionDecodeErr::Malformed {
1289                         err_msg: "HMAC Check failed",
1290                         err_code: 0x8000 | 0x4000 | 5,
1291                 });
1292         }
1293
1294         let mut chacha = ChaCha20::new(&rho, &[0u8; 8]);
1295         let mut chacha_stream = ChaChaReader { chacha: &mut chacha, read: Cursor::new(&hop_data[..]) };
1296         match R::read(&mut chacha_stream, read_args) {
1297                 Err(err) => {
1298                         let error_code = match err {
1299                                 // Unknown realm byte
1300                                 msgs::DecodeError::UnknownVersion => 0x4000 | 1,
1301                                 // invalid_onion_payload
1302                                 msgs::DecodeError::UnknownRequiredFeature
1303                                 | msgs::DecodeError::InvalidValue
1304                                 | msgs::DecodeError::ShortRead => 0x4000 | 22,
1305                                 // Should never happen
1306                                 _ => 0x2000 | 2,
1307                         };
1308                         return Err(OnionDecodeErr::Relay {
1309                                 err_msg: "Unable to decode our hop data",
1310                                 err_code: error_code,
1311                         });
1312                 },
1313                 Ok(msg) => {
1314                         let mut hmac = [0; 32];
1315                         if let Err(_) = chacha_stream.read_exact(&mut hmac[..]) {
1316                                 return Err(OnionDecodeErr::Relay {
1317                                         err_msg: "Unable to decode our hop data",
1318                                         err_code: 0x4000 | 22,
1319                                 });
1320                         }
1321                         if hmac == [0; 32] {
1322                                 #[cfg(test)]
1323                                 {
1324                                         if chacha_stream.read.position() < hop_data.len() as u64 - 64 {
1325                                                 // In tests, make sure that the initial onion packet data is, at least, non-0.
1326                                                 // We could do some fancy randomness test here, but, ehh, whatever.
1327                                                 // This checks for the issue where you can calculate the path length given the
1328                                                 // onion data as all the path entries that the originator sent will be here
1329                                                 // as-is (and were originally 0s).
1330                                                 // Of course reverse path calculation is still pretty easy given naive routing
1331                                                 // algorithms, but this fixes the most-obvious case.
1332                                                 let mut next_bytes = [0; 32];
1333                                                 chacha_stream.read_exact(&mut next_bytes).unwrap();
1334                                                 assert_ne!(next_bytes[..], [0; 32][..]);
1335                                                 chacha_stream.read_exact(&mut next_bytes).unwrap();
1336                                                 assert_ne!(next_bytes[..], [0; 32][..]);
1337                                         }
1338                                 }
1339                                 return Ok((msg, None)); // We are the final destination for this packet
1340                         } else {
1341                                 let mut new_packet_bytes = N::new(hop_data.len());
1342                                 let read_pos = hop_data.len() - chacha_stream.read.position() as usize;
1343                                 chacha_stream.read_exact(&mut new_packet_bytes.as_mut()[..read_pos]).unwrap();
1344                                 #[cfg(debug_assertions)]
1345                                 {
1346                                         // Check two things:
1347                                         // a) that the behavior of our stream here will return Ok(0) even if the TLV
1348                                         //    read above emptied out our buffer and the unwrap() wont needlessly panic
1349                                         // b) that we didn't somehow magically end up with extra data.
1350                                         let mut t = [0; 1];
1351                                         debug_assert!(chacha_stream.read(&mut t).unwrap() == 0);
1352                                 }
1353                                 // Once we've emptied the set of bytes our peer gave us, encrypt 0 bytes until we
1354                                 // fill the onion hop data we'll forward to our next-hop peer.
1355                                 chacha_stream.chacha.process_in_place(&mut new_packet_bytes.as_mut()[read_pos..]);
1356                                 return Ok((msg, Some((hmac, new_packet_bytes)))); // This packet needs forwarding
1357                         }
1358                 },
1359         }
1360 }
1361
1362 #[cfg(test)]
1363 mod tests {
1364         use crate::io;
1365         use crate::ln::features::{ChannelFeatures, NodeFeatures};
1366         use crate::ln::msgs;
1367         use crate::ln::types::PaymentHash;
1368         use crate::routing::router::{Path, Route, RouteHop};
1369         use crate::util::ser::{VecWriter, Writeable, Writer};
1370
1371         #[allow(unused_imports)]
1372         use crate::prelude::*;
1373
1374         use bitcoin::hashes::hex::FromHex;
1375         use bitcoin::secp256k1::Secp256k1;
1376         use bitcoin::secp256k1::{PublicKey, SecretKey};
1377
1378         use super::OnionKeys;
1379
1380         fn get_test_session_key() -> SecretKey {
1381                 let hex = "4141414141414141414141414141414141414141414141414141414141414141";
1382                 SecretKey::from_slice(&<Vec<u8>>::from_hex(hex).unwrap()[..]).unwrap()
1383         }
1384
1385         fn build_test_onion_keys() -> Vec<OnionKeys> {
1386                 // Keys from BOLT 4, used in both test vector tests
1387                 let secp_ctx = Secp256k1::new();
1388
1389                 let route = Route {
1390                         paths: vec![Path { hops: vec![
1391                                         RouteHop {
1392                                                 pubkey: PublicKey::from_slice(&<Vec<u8>>::from_hex("02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619").unwrap()[..]).unwrap(),
1393                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
1394                                                 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.
1395                                         },
1396                                         RouteHop {
1397                                                 pubkey: PublicKey::from_slice(&<Vec<u8>>::from_hex("0324653eac434488002cc06bbfb7f10fe18991e35f9fe4302dbea6d2353dc0ab1c").unwrap()[..]).unwrap(),
1398                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
1399                                                 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.
1400                                         },
1401                                         RouteHop {
1402                                                 pubkey: PublicKey::from_slice(&<Vec<u8>>::from_hex("027f31ebc5462c1fdce1b737ecff52d37d75dea43ce11c74d25aa297165faa2007").unwrap()[..]).unwrap(),
1403                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
1404                                                 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.
1405                                         },
1406                                         RouteHop {
1407                                                 pubkey: PublicKey::from_slice(&<Vec<u8>>::from_hex("032c0b7cf95324a07d05398b240174dc0c2be444d96b159aa6c7f7b1e668680991").unwrap()[..]).unwrap(),
1408                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
1409                                                 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.
1410                                         },
1411                                         RouteHop {
1412                                                 pubkey: PublicKey::from_slice(&<Vec<u8>>::from_hex("02edabbd16b41c8371b92ef2f04c1185b4f03b6dcd52ba9b78d9d7c89c8f221145").unwrap()[..]).unwrap(),
1413                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
1414                                                 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.
1415                                         },
1416                         ], blinded_tail: None }],
1417                         route_params: None,
1418                 };
1419
1420                 let onion_keys =
1421                         super::construct_onion_keys(&secp_ctx, &route.paths[0], &get_test_session_key())
1422                                 .unwrap();
1423                 assert_eq!(onion_keys.len(), route.paths[0].hops.len());
1424                 onion_keys
1425         }
1426
1427         #[test]
1428         fn onion_vectors() {
1429                 let onion_keys = build_test_onion_keys();
1430
1431                 // Test generation of ephemeral keys and secrets. These values used to be part of the BOLT4
1432                 // test vectors, but have since been removed. We keep them as they provide test coverage.
1433                 let hex = "53eb63ea8a3fec3b3cd433b85cd62a4b145e1dda09391b348c4e1cd36a03ea66";
1434                 assert_eq!(
1435                         onion_keys[0].shared_secret.secret_bytes(),
1436                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1437                 );
1438
1439                 let hex = "2ec2e5da605776054187180343287683aa6a51b4b1c04d6dd49c45d8cffb3c36";
1440                 assert_eq!(onion_keys[0].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
1441
1442                 let hex = "02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619";
1443                 assert_eq!(
1444                         onion_keys[0].ephemeral_pubkey.serialize()[..],
1445                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1446                 );
1447
1448                 let hex = "ce496ec94def95aadd4bec15cdb41a740c9f2b62347c4917325fcc6fb0453986";
1449                 assert_eq!(onion_keys[0].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1450
1451                 let hex = "b57061dc6d0a2b9f261ac410c8b26d64ac5506cbba30267a649c28c179400eba";
1452                 assert_eq!(onion_keys[0].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1453
1454                 let hex = "a6519e98832a0b179f62123b3567c106db99ee37bef036e783263602f3488fae";
1455                 assert_eq!(
1456                         onion_keys[1].shared_secret.secret_bytes(),
1457                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1458                 );
1459
1460                 let hex = "bf66c28bc22e598cfd574a1931a2bafbca09163df2261e6d0056b2610dab938f";
1461                 assert_eq!(onion_keys[1].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
1462
1463                 let hex = "028f9438bfbf7feac2e108d677e3a82da596be706cc1cf342b75c7b7e22bf4e6e2";
1464                 assert_eq!(
1465                         onion_keys[1].ephemeral_pubkey.serialize()[..],
1466                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1467                 );
1468
1469                 let hex = "450ffcabc6449094918ebe13d4f03e433d20a3d28a768203337bc40b6e4b2c59";
1470                 assert_eq!(onion_keys[1].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1471
1472                 let hex = "05ed2b4a3fb023c2ff5dd6ed4b9b6ea7383f5cfe9d59c11d121ec2c81ca2eea9";
1473                 assert_eq!(onion_keys[1].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1474
1475                 let hex = "3a6b412548762f0dbccce5c7ae7bb8147d1caf9b5471c34120b30bc9c04891cc";
1476                 assert_eq!(
1477                         onion_keys[2].shared_secret.secret_bytes(),
1478                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1479                 );
1480
1481                 let hex = "a1f2dadd184eb1627049673f18c6325814384facdee5bfd935d9cb031a1698a5";
1482                 assert_eq!(onion_keys[2].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
1483
1484                 let hex = "03bfd8225241ea71cd0843db7709f4c222f62ff2d4516fd38b39914ab6b83e0da0";
1485                 assert_eq!(
1486                         onion_keys[2].ephemeral_pubkey.serialize()[..],
1487                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1488                 );
1489
1490                 let hex = "11bf5c4f960239cb37833936aa3d02cea82c0f39fd35f566109c41f9eac8deea";
1491                 assert_eq!(onion_keys[2].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1492
1493                 let hex = "caafe2820fa00eb2eeb78695ae452eba38f5a53ed6d53518c5c6edf76f3f5b78";
1494                 assert_eq!(onion_keys[2].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1495
1496                 let hex = "21e13c2d7cfe7e18836df50872466117a295783ab8aab0e7ecc8c725503ad02d";
1497                 assert_eq!(
1498                         onion_keys[3].shared_secret.secret_bytes(),
1499                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1500                 );
1501
1502                 let hex = "7cfe0b699f35525029ae0fa437c69d0f20f7ed4e3916133f9cacbb13c82ff262";
1503                 assert_eq!(onion_keys[3].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
1504
1505                 let hex = "031dde6926381289671300239ea8e57ffaf9bebd05b9a5b95beaf07af05cd43595";
1506                 assert_eq!(
1507                         onion_keys[3].ephemeral_pubkey.serialize()[..],
1508                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1509                 );
1510
1511                 let hex = "cbe784ab745c13ff5cffc2fbe3e84424aa0fd669b8ead4ee562901a4a4e89e9e";
1512                 assert_eq!(onion_keys[3].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1513
1514                 let hex = "5052aa1b3d9f0655a0932e50d42f0c9ba0705142c25d225515c45f47c0036ee9";
1515                 assert_eq!(onion_keys[3].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1516
1517                 let hex = "b5756b9b542727dbafc6765a49488b023a725d631af688fc031217e90770c328";
1518                 assert_eq!(
1519                         onion_keys[4].shared_secret.secret_bytes(),
1520                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1521                 );
1522
1523                 let hex = "c96e00dddaf57e7edcd4fb5954be5b65b09f17cb6d20651b4e90315be5779205";
1524                 assert_eq!(onion_keys[4].blinding_factor[..], <Vec<u8>>::from_hex(hex).unwrap()[..]);
1525
1526                 let hex = "03a214ebd875aab6ddfd77f22c5e7311d7f77f17a169e599f157bbcdae8bf071f4";
1527                 assert_eq!(
1528                         onion_keys[4].ephemeral_pubkey.serialize()[..],
1529                         <Vec<u8>>::from_hex(hex).unwrap()[..]
1530                 );
1531
1532                 let hex = "034e18b8cc718e8af6339106e706c52d8df89e2b1f7e9142d996acf88df8799b";
1533                 assert_eq!(onion_keys[4].rho, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1534
1535                 let hex = "8e45e5c61c2b24cb6382444db6698727afb063adecd72aada233d4bf273d975a";
1536                 assert_eq!(onion_keys[4].mu, <Vec<u8>>::from_hex(hex).unwrap()[..]);
1537
1538                 // Packet creation test vectors from BOLT 4 (see
1539                 // https://github.com/lightning/bolts/blob/16973e2b857e853308cafd59e42fa830d75b1642/bolt04/onion-test.json).
1540                 // Note that we represent the test vector payloads 2 and 5 through RawOnionHopData::data
1541                 // with raw hex instead of our in-memory enums, as the payloads contains custom types, and
1542                 // we have no way of representing that with our enums.
1543                 let payloads = vec!(
1544                         RawOnionHopData::new(msgs::OutboundOnionPayload::Forward {
1545                                 short_channel_id: 1,
1546                                 amt_to_forward: 15000,
1547                                 outgoing_cltv_value: 1500,
1548                         }),
1549                         /*
1550                         The second payload is represented by raw hex as it contains custom type data. Content:
1551                         1. length "52" (payload_length 82).
1552
1553                         The first part of the payload has the `NonFinalNode` format, with content as follows:
1554                         2. amt_to_forward "020236b0"
1555                            02 (type amt_to_forward) 02 (length 2) 36b0 (value 14000)
1556                         3. outgoing_cltv_value "04020578"
1557                            04 (type outgoing_cltv_value) 02 (length 2) 0578 (value 1400)
1558                         4. short_channel_id "06080000000000000002"
1559                            06 (type short_channel_id) 08 (length 8) 0000000000000002 (value 2)
1560
1561                         The rest of the payload is custom type data:
1562                         5. custom_record "fd02013c0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f"
1563                         */
1564                         RawOnionHopData {
1565                                 data: <Vec<u8>>::from_hex("52020236b00402057806080000000000000002fd02013c0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f").unwrap(),
1566                         },
1567                         RawOnionHopData::new(msgs::OutboundOnionPayload::Forward {
1568                                 short_channel_id: 3,
1569                                 amt_to_forward: 12500,
1570                                 outgoing_cltv_value: 1250,
1571                         }),
1572                         RawOnionHopData::new(msgs::OutboundOnionPayload::Forward {
1573                                 short_channel_id: 4,
1574                                 amt_to_forward: 10000,
1575                                 outgoing_cltv_value: 1000,
1576                         }),
1577                         /*
1578                         The fifth payload is represented by raw hex as it contains custom type data. Content:
1579                         1. length "fd0110" (payload_length 272).
1580
1581                         The first part of the payload has the `FinalNode` format, with content as follows:
1582                         1. amt_to_forward "02022710"
1583                            02 (type amt_to_forward) 02 (length 2) 2710 (value 10000)
1584                         2. outgoing_cltv_value "040203e8"
1585                            04 (type outgoing_cltv_value) 02 (length 2) 03e8 (value 1000)
1586                         3. payment_data "082224a33562c54507a9334e79f0dc4f17d407e6d7c61f0e2f3d0d38599502f617042710"
1587                            08 (type short_channel_id) 22 (length 34) 24a33562c54507a9334e79f0dc4f17d407e6d7c61f0e2f3d0d38599502f61704 (payment_secret) 2710 (total_msat value 10000)
1588
1589                         The rest of the payload is custom type data:
1590                         4. custom_record "fd012de02a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a"
1591                         */
1592                         RawOnionHopData {
1593                                 data: <Vec<u8>>::from_hex("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").unwrap(),
1594                         },
1595                 );
1596
1597                 // Verify that the serialized OnionHopDataFormat::NonFinalNode tlv payloads matches the test vectors
1598                 let mut w = VecWriter(Vec::new());
1599                 payloads[0].write(&mut w).unwrap();
1600                 let hop_1_serialized_payload = w.0;
1601                 let hex = "1202023a98040205dc06080000000000000001";
1602                 let expected_serialized_hop_1_payload = &<Vec<u8>>::from_hex(hex).unwrap()[..];
1603                 assert_eq!(hop_1_serialized_payload, expected_serialized_hop_1_payload);
1604
1605                 w = VecWriter(Vec::new());
1606                 payloads[2].write(&mut w).unwrap();
1607                 let hop_3_serialized_payload = w.0;
1608                 let hex = "12020230d4040204e206080000000000000003";
1609                 let expected_serialized_hop_3_payload = &<Vec<u8>>::from_hex(hex).unwrap()[..];
1610                 assert_eq!(hop_3_serialized_payload, expected_serialized_hop_3_payload);
1611
1612                 w = VecWriter(Vec::new());
1613                 payloads[3].write(&mut w).unwrap();
1614                 let hop_4_serialized_payload = w.0;
1615                 let hex = "1202022710040203e806080000000000000004";
1616                 let expected_serialized_hop_4_payload = &<Vec<u8>>::from_hex(hex).unwrap()[..];
1617                 assert_eq!(hop_4_serialized_payload, expected_serialized_hop_4_payload);
1618
1619                 let pad_keytype_seed =
1620                         super::gen_pad_from_shared_secret(&get_test_session_key().secret_bytes());
1621
1622                 let packet: msgs::OnionPacket = super::construct_onion_packet_with_writable_hopdata::<_>(
1623                         payloads,
1624                         onion_keys,
1625                         pad_keytype_seed,
1626                         &PaymentHash([0x42; 32]),
1627                 )
1628                 .unwrap();
1629
1630                 let hex = 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
1631                 assert_eq!(packet.encode(), <Vec<u8>>::from_hex(hex).unwrap());
1632         }
1633
1634         #[test]
1635         fn test_failure_packet_onion() {
1636                 // Returning Errors test vectors from BOLT 4
1637
1638                 let onion_keys = build_test_onion_keys();
1639                 let onion_error =
1640                         super::build_failure_packet(onion_keys[4].shared_secret.as_ref(), 0x2002, &[0; 0]);
1641                 let hex = "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";
1642                 assert_eq!(onion_error.encode(), <Vec<u8>>::from_hex(hex).unwrap());
1643
1644                 let onion_packet_1 = super::encrypt_failure_packet(
1645                         onion_keys[4].shared_secret.as_ref(),
1646                         &onion_error.encode()[..],
1647                 );
1648                 let hex = "a5e6bd0c74cb347f10cce367f949098f2457d14c046fd8a22cb96efb30b0fdcda8cb9168b50f2fd45edd73c1b0c8b33002df376801ff58aaa94000bf8a86f92620f343baef38a580102395ae3abf9128d1047a0736ff9b83d456740ebbb4aeb3aa9737f18fb4afb4aa074fb26c4d702f42968888550a3bded8c05247e045b866baef0499f079fdaeef6538f31d44deafffdfd3afa2fb4ca9082b8f1c465371a9894dd8c243fb4847e004f5256b3e90e2edde4c9fb3082ddfe4d1e734cacd96ef0706bf63c9984e22dc98851bcccd1c3494351feb458c9c6af41c0044bea3c47552b1d992ae542b17a2d0bba1a096c78d169034ecb55b6e3a7263c26017f033031228833c1daefc0dedb8cf7c3e37c9c37ebfe42f3225c326e8bcfd338804c145b16e34e4";
1649                 assert_eq!(onion_packet_1.data, <Vec<u8>>::from_hex(hex).unwrap());
1650
1651                 let onion_packet_2 = super::encrypt_failure_packet(
1652                         onion_keys[3].shared_secret.as_ref(),
1653                         &onion_packet_1.data[..],
1654                 );
1655                 let hex = "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";
1656                 assert_eq!(onion_packet_2.data, <Vec<u8>>::from_hex(hex).unwrap());
1657
1658                 let onion_packet_3 = super::encrypt_failure_packet(
1659                         onion_keys[2].shared_secret.as_ref(),
1660                         &onion_packet_2.data[..],
1661                 );
1662                 let hex = "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";
1663                 assert_eq!(onion_packet_3.data, <Vec<u8>>::from_hex(hex).unwrap());
1664
1665                 let onion_packet_4 = super::encrypt_failure_packet(
1666                         onion_keys[1].shared_secret.as_ref(),
1667                         &onion_packet_3.data[..],
1668                 );
1669                 let hex = "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";
1670                 assert_eq!(onion_packet_4.data, <Vec<u8>>::from_hex(hex).unwrap());
1671
1672                 let onion_packet_5 = super::encrypt_failure_packet(
1673                         onion_keys[0].shared_secret.as_ref(),
1674                         &onion_packet_4.data[..],
1675                 );
1676                 let hex = "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";
1677                 assert_eq!(onion_packet_5.data, <Vec<u8>>::from_hex(hex).unwrap());
1678         }
1679
1680         struct RawOnionHopData {
1681                 data: Vec<u8>,
1682         }
1683         impl RawOnionHopData {
1684                 fn new(orig: msgs::OutboundOnionPayload) -> Self {
1685                         Self { data: orig.encode() }
1686                 }
1687         }
1688         impl Writeable for RawOnionHopData {
1689                 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
1690                         writer.write_all(&self.data[..])
1691                 }
1692         }
1693 }