2c20fb17734b74a3394ca724ad732a8ec5f3525b
[rust-lightning] / lightning / src / ln / onion_utils.rs
1 // This file is Copyright its original authors, visible in version control
2 // history.
3 //
4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
7 // You may not use this file except in accordance with one or both of these
8 // licenses.
9
10 use crate::ln::{PaymentHash, PaymentPreimage};
11 use crate::ln::channelmanager::{HTLCSource, RecipientOnionFields};
12 use crate::ln::msgs;
13 use crate::ln::wire::Encode;
14 use crate::routing::gossip::NetworkUpdate;
15 use crate::routing::router::RouteHop;
16 use crate::util::chacha20::{ChaCha20, ChaChaReader};
17 use crate::util::errors::{self, APIError};
18 use crate::util::ser::{Readable, ReadableArgs, Writeable, Writer, LengthCalculatingWriter};
19 use crate::util::logger::Logger;
20
21 use bitcoin::hashes::{Hash, HashEngine};
22 use bitcoin::hashes::cmp::fixed_time_eq;
23 use bitcoin::hashes::hmac::{Hmac, HmacEngine};
24 use bitcoin::hashes::sha256::Hash as Sha256;
25
26 use bitcoin::secp256k1::{SecretKey, PublicKey, Scalar};
27 use bitcoin::secp256k1::Secp256k1;
28 use bitcoin::secp256k1::ecdh::SharedSecret;
29 use bitcoin::secp256k1;
30
31 use crate::prelude::*;
32 use crate::io::{Cursor, Read};
33 use core::convert::{AsMut, TryInto};
34 use core::ops::Deref;
35
36 pub(crate) struct OnionKeys {
37         #[cfg(test)]
38         pub(crate) shared_secret: SharedSecret,
39         #[cfg(test)]
40         pub(crate) blinding_factor: [u8; 32],
41         pub(crate) ephemeral_pubkey: PublicKey,
42         pub(crate) rho: [u8; 32],
43         pub(crate) mu: [u8; 32],
44 }
45
46 #[inline]
47 pub(crate) fn gen_rho_from_shared_secret(shared_secret: &[u8]) -> [u8; 32] {
48         assert_eq!(shared_secret.len(), 32);
49         let mut hmac = HmacEngine::<Sha256>::new(&[0x72, 0x68, 0x6f]); // rho
50         hmac.input(&shared_secret);
51         Hmac::from_engine(hmac).into_inner()
52 }
53
54 #[inline]
55 pub(crate) fn gen_rho_mu_from_shared_secret(shared_secret: &[u8]) -> ([u8; 32], [u8; 32]) {
56         assert_eq!(shared_secret.len(), 32);
57         ({
58                 let mut hmac = HmacEngine::<Sha256>::new(&[0x72, 0x68, 0x6f]); // rho
59                 hmac.input(&shared_secret);
60                 Hmac::from_engine(hmac).into_inner()
61         },
62         {
63                 let mut hmac = HmacEngine::<Sha256>::new(&[0x6d, 0x75]); // mu
64                 hmac.input(&shared_secret);
65                 Hmac::from_engine(hmac).into_inner()
66         })
67 }
68
69 #[inline]
70 pub(super) fn gen_um_from_shared_secret(shared_secret: &[u8]) -> [u8; 32] {
71         assert_eq!(shared_secret.len(), 32);
72         let mut hmac = HmacEngine::<Sha256>::new(&[0x75, 0x6d]); // um
73         hmac.input(&shared_secret);
74         Hmac::from_engine(hmac).into_inner()
75 }
76
77 #[inline]
78 pub(super) fn gen_ammag_from_shared_secret(shared_secret: &[u8]) -> [u8; 32] {
79         assert_eq!(shared_secret.len(), 32);
80         let mut hmac = HmacEngine::<Sha256>::new(&[0x61, 0x6d, 0x6d, 0x61, 0x67]); // ammag
81         hmac.input(&shared_secret);
82         Hmac::from_engine(hmac).into_inner()
83 }
84
85 #[cfg(test)]
86 #[inline]
87 pub(super) fn gen_pad_from_shared_secret(shared_secret: &[u8]) -> [u8; 32] {
88         assert_eq!(shared_secret.len(), 32);
89         let mut hmac = HmacEngine::<Sha256>::new(&[0x70, 0x61, 0x64]); // pad
90         hmac.input(&shared_secret);
91         Hmac::from_engine(hmac).into_inner()
92 }
93
94 pub(crate) fn next_hop_packet_pubkey<T: secp256k1::Signing + secp256k1::Verification>(secp_ctx: &Secp256k1<T>, packet_pubkey: PublicKey, packet_shared_secret: &[u8; 32]) -> Result<PublicKey, secp256k1::Error> {
95         let blinding_factor = {
96                 let mut sha = Sha256::engine();
97                 sha.input(&packet_pubkey.serialize()[..]);
98                 sha.input(packet_shared_secret);
99                 Sha256::from_engine(sha).into_inner()
100         };
101
102         packet_pubkey.mul_tweak(secp_ctx, &Scalar::from_be_bytes(blinding_factor).unwrap())
103 }
104
105 // can only fail if an intermediary hop has an invalid public key or session_priv is invalid
106 #[inline]
107 pub(super) fn construct_onion_keys_callback<T: secp256k1::Signing, FType: FnMut(SharedSecret, [u8; 32], PublicKey, &RouteHop, usize)> (secp_ctx: &Secp256k1<T>, path: &Vec<RouteHop>, session_priv: &SecretKey, mut callback: FType) -> Result<(), secp256k1::Error> {
108         let mut blinded_priv = session_priv.clone();
109         let mut blinded_pub = PublicKey::from_secret_key(secp_ctx, &blinded_priv);
110
111         for (idx, hop) in path.iter().enumerate() {
112                 let shared_secret = SharedSecret::new(&hop.pubkey, &blinded_priv);
113
114                 let mut sha = Sha256::engine();
115                 sha.input(&blinded_pub.serialize()[..]);
116                 sha.input(shared_secret.as_ref());
117                 let blinding_factor = Sha256::from_engine(sha).into_inner();
118
119                 let ephemeral_pubkey = blinded_pub;
120
121                 blinded_priv = blinded_priv.mul_tweak(&Scalar::from_be_bytes(blinding_factor).unwrap())?;
122                 blinded_pub = PublicKey::from_secret_key(secp_ctx, &blinded_priv);
123
124                 callback(shared_secret, blinding_factor, ephemeral_pubkey, hop, idx);
125         }
126
127         Ok(())
128 }
129
130 // can only fail if an intermediary hop has an invalid public key or session_priv is invalid
131 pub(super) fn construct_onion_keys<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, path: &Vec<RouteHop>, session_priv: &SecretKey) -> Result<Vec<OnionKeys>, secp256k1::Error> {
132         let mut res = Vec::with_capacity(path.len());
133
134         construct_onion_keys_callback(secp_ctx, path, session_priv, |shared_secret, _blinding_factor, ephemeral_pubkey, _, _| {
135                 let (rho, mu) = gen_rho_mu_from_shared_secret(shared_secret.as_ref());
136
137                 res.push(OnionKeys {
138                         #[cfg(test)]
139                         shared_secret,
140                         #[cfg(test)]
141                         blinding_factor: _blinding_factor,
142                         ephemeral_pubkey,
143                         rho,
144                         mu,
145                 });
146         })?;
147
148         Ok(res)
149 }
150
151 /// returns the hop data, as well as the first-hop value_msat and CLTV value we should send.
152 pub(super) fn build_onion_payloads(path: &Vec<RouteHop>, total_msat: u64, mut recipient_onion: RecipientOnionFields, starting_htlc_offset: u32, keysend_preimage: &Option<PaymentPreimage>) -> Result<(Vec<msgs::OnionHopData>, u64, u32), APIError> {
153         let mut cur_value_msat = 0u64;
154         let mut cur_cltv = starting_htlc_offset;
155         let mut last_short_channel_id = 0;
156         let mut res: Vec<msgs::OnionHopData> = Vec::with_capacity(path.len());
157
158         for (idx, hop) in path.iter().rev().enumerate() {
159                 // First hop gets special values so that it can check, on receipt, that everything is
160                 // exactly as it should be (and the next hop isn't trying to probe to find out if we're
161                 // the intended recipient).
162                 let value_msat = if cur_value_msat == 0 { hop.fee_msat } else { cur_value_msat };
163                 let cltv = if cur_cltv == starting_htlc_offset { hop.cltv_expiry_delta + starting_htlc_offset } else { cur_cltv };
164                 res.insert(0, msgs::OnionHopData {
165                         format: if idx == 0 {
166                                 msgs::OnionHopDataFormat::FinalNode {
167                                         payment_data: if let Some(secret) = recipient_onion.payment_secret.take() {
168                                                 Some(msgs::FinalOnionHopData {
169                                                         payment_secret: secret,
170                                                         total_msat,
171                                                 })
172                                         } else { None },
173                                         keysend_preimage: *keysend_preimage,
174                                 }
175                         } else {
176                                 msgs::OnionHopDataFormat::NonFinalNode {
177                                         short_channel_id: last_short_channel_id,
178                                 }
179                         },
180                         amt_to_forward: value_msat,
181                         outgoing_cltv_value: cltv,
182                 });
183                 cur_value_msat += hop.fee_msat;
184                 if cur_value_msat >= 21000000 * 100000000 * 1000 {
185                         return Err(APIError::InvalidRoute{err: "Channel fees overflowed?".to_owned()});
186                 }
187                 cur_cltv += hop.cltv_expiry_delta as u32;
188                 if cur_cltv >= 500000000 {
189                         return Err(APIError::InvalidRoute{err: "Channel CLTV overflowed?".to_owned()});
190                 }
191                 last_short_channel_id = hop.short_channel_id;
192         }
193         Ok((res, cur_value_msat, cur_cltv))
194 }
195
196 /// Length of the onion data packet. Before TLV-based onions this was 20 65-byte hops, though now
197 /// the hops can be of variable length.
198 pub(crate) const ONION_DATA_LEN: usize = 20*65;
199
200 #[inline]
201 fn shift_slice_right(arr: &mut [u8], amt: usize) {
202         for i in (amt..arr.len()).rev() {
203                 arr[i] = arr[i-amt];
204         }
205         for i in 0..amt {
206                 arr[i] = 0;
207         }
208 }
209
210 pub(super) fn route_size_insane(payloads: &Vec<msgs::OnionHopData>) -> bool {
211         let mut len = 0;
212         for payload in payloads.iter() {
213                 let mut payload_len = LengthCalculatingWriter(0);
214                 payload.write(&mut payload_len).expect("Failed to calculate length");
215                 assert!(payload_len.0 + 32 < ONION_DATA_LEN);
216                 len += payload_len.0 + 32;
217                 if len > ONION_DATA_LEN {
218                         return true;
219                 }
220         }
221         false
222 }
223
224 /// panics if route_size_insane(payloads)
225 pub(super) fn construct_onion_packet(payloads: Vec<msgs::OnionHopData>, onion_keys: Vec<OnionKeys>, prng_seed: [u8; 32], associated_data: &PaymentHash) -> msgs::OnionPacket {
226         let mut packet_data = [0; ONION_DATA_LEN];
227
228         let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
229         chacha.process(&[0; ONION_DATA_LEN], &mut packet_data);
230
231         construct_onion_packet_with_init_noise::<_, _>(
232                 payloads, onion_keys, FixedSizeOnionPacket(packet_data), Some(associated_data))
233 }
234
235 #[cfg(test)]
236 /// Used in testing to write bogus `BogusOnionHopData` as well as `RawOnionHopData`, which is
237 /// otherwise not representable in `msgs::OnionHopData`.
238 pub(super) fn construct_onion_packet_with_writable_hopdata<HD: Writeable>(payloads: Vec<HD>, onion_keys: Vec<OnionKeys>, prng_seed: [u8; 32], associated_data: &PaymentHash) -> msgs::OnionPacket {
239         let mut packet_data = [0; ONION_DATA_LEN];
240
241         let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
242         chacha.process(&[0; ONION_DATA_LEN], &mut packet_data);
243
244         construct_onion_packet_with_init_noise::<_, _>(
245                 payloads, onion_keys, FixedSizeOnionPacket(packet_data), Some(associated_data))
246 }
247
248 /// Since onion message packets and onion payment packets have different lengths but are otherwise
249 /// identical, we use this trait to allow `construct_onion_packet_with_init_noise` to return either
250 /// type.
251 pub(crate) trait Packet {
252         type Data: AsMut<[u8]>;
253         fn new(pubkey: PublicKey, hop_data: Self::Data, hmac: [u8; 32]) -> Self;
254 }
255
256 // Needed for rustc versions older than 1.47 to avoid E0277: "arrays only have std trait
257 // implementations for lengths 0..=32".
258 pub(crate) struct FixedSizeOnionPacket(pub(crate) [u8; ONION_DATA_LEN]);
259
260 impl AsMut<[u8]> for FixedSizeOnionPacket {
261         fn as_mut(&mut self) -> &mut [u8] {
262                 &mut self.0
263         }
264 }
265
266 pub(crate) fn payloads_serialized_length<HD: Writeable>(payloads: &Vec<HD>) -> usize {
267         payloads.iter().map(|p| p.serialized_length() + 32 /* HMAC */).sum()
268 }
269
270 /// panics if payloads_serialized_length(payloads) > packet_data_len
271 pub(crate) fn construct_onion_message_packet<HD: Writeable, P: Packet<Data = Vec<u8>>>(
272         payloads: Vec<HD>, onion_keys: Vec<OnionKeys>, prng_seed: [u8; 32], packet_data_len: usize) -> P
273 {
274         let mut packet_data = vec![0; packet_data_len];
275
276         let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
277         chacha.process_in_place(&mut packet_data);
278
279         construct_onion_packet_with_init_noise::<_, _>(payloads, onion_keys, packet_data, None)
280 }
281
282 /// panics if payloads_serialized_length(payloads) > packet_data.len()
283 fn construct_onion_packet_with_init_noise<HD: Writeable, P: Packet>(
284         mut payloads: Vec<HD>, onion_keys: Vec<OnionKeys>, mut packet_data: P::Data, associated_data: Option<&PaymentHash>) -> P
285 {
286         let filler = {
287                 let packet_data = packet_data.as_mut();
288                 const ONION_HOP_DATA_LEN: usize = 65; // We may decrease this eventually after TLV is common
289                 let mut res = Vec::with_capacity(ONION_HOP_DATA_LEN * (payloads.len() - 1));
290
291                 let mut pos = 0;
292                 for (i, (payload, keys)) in payloads.iter().zip(onion_keys.iter()).enumerate() {
293                         if i == payloads.len() - 1 { break; }
294
295                         let mut chacha = ChaCha20::new(&keys.rho, &[0u8; 8]);
296                         for _ in 0..(packet_data.len() - pos) { // TODO: Batch this.
297                                 let mut dummy = [0; 1];
298                                 chacha.process_in_place(&mut dummy); // We don't have a seek function :(
299                         }
300
301                         let mut payload_len = LengthCalculatingWriter(0);
302                         payload.write(&mut payload_len).expect("Failed to calculate length");
303                         pos += payload_len.0 + 32;
304                         assert!(pos <= packet_data.len());
305
306                         res.resize(pos, 0u8);
307                         chacha.process_in_place(&mut res);
308                 }
309                 res
310         };
311
312         let mut hmac_res = [0; 32];
313         for (i, (payload, keys)) in payloads.iter_mut().zip(onion_keys.iter()).rev().enumerate() {
314                 let mut payload_len = LengthCalculatingWriter(0);
315                 payload.write(&mut payload_len).expect("Failed to calculate length");
316
317                 let packet_data = packet_data.as_mut();
318                 shift_slice_right(packet_data, payload_len.0 + 32);
319                 packet_data[0..payload_len.0].copy_from_slice(&payload.encode()[..]);
320                 packet_data[payload_len.0..(payload_len.0 + 32)].copy_from_slice(&hmac_res);
321
322                 let mut chacha = ChaCha20::new(&keys.rho, &[0u8; 8]);
323                 chacha.process_in_place(packet_data);
324
325                 if i == 0 {
326                         packet_data[ONION_DATA_LEN - filler.len()..ONION_DATA_LEN].copy_from_slice(&filler[..]);
327                 }
328
329                 let mut hmac = HmacEngine::<Sha256>::new(&keys.mu);
330                 hmac.input(packet_data);
331                 if let Some(associated_data) = associated_data {
332                         hmac.input(&associated_data.0[..]);
333                 }
334                 hmac_res = Hmac::from_engine(hmac).into_inner();
335         }
336
337         P::new(onion_keys.first().unwrap().ephemeral_pubkey, packet_data, hmac_res)
338 }
339
340 /// Encrypts a failure packet. raw_packet can either be a
341 /// msgs::DecodedOnionErrorPacket.encode() result or a msgs::OnionErrorPacket.data element.
342 pub(super) fn encrypt_failure_packet(shared_secret: &[u8], raw_packet: &[u8]) -> msgs::OnionErrorPacket {
343         let ammag = gen_ammag_from_shared_secret(&shared_secret);
344
345         let mut packet_crypted = Vec::with_capacity(raw_packet.len());
346         packet_crypted.resize(raw_packet.len(), 0);
347         let mut chacha = ChaCha20::new(&ammag, &[0u8; 8]);
348         chacha.process(&raw_packet, &mut packet_crypted[..]);
349         msgs::OnionErrorPacket {
350                 data: packet_crypted,
351         }
352 }
353
354 pub(super) fn build_failure_packet(shared_secret: &[u8], failure_type: u16, failure_data: &[u8]) -> msgs::DecodedOnionErrorPacket {
355         assert_eq!(shared_secret.len(), 32);
356         assert!(failure_data.len() <= 256 - 2);
357
358         let um = gen_um_from_shared_secret(&shared_secret);
359
360         let failuremsg = {
361                 let mut res = Vec::with_capacity(2 + failure_data.len());
362                 res.push(((failure_type >> 8) & 0xff) as u8);
363                 res.push(((failure_type >> 0) & 0xff) as u8);
364                 res.extend_from_slice(&failure_data[..]);
365                 res
366         };
367         let pad = {
368                 let mut res = Vec::with_capacity(256 - 2 - failure_data.len());
369                 res.resize(256 - 2 - failure_data.len(), 0);
370                 res
371         };
372         let mut packet = msgs::DecodedOnionErrorPacket {
373                 hmac: [0; 32],
374                 failuremsg,
375                 pad,
376         };
377
378         let mut hmac = HmacEngine::<Sha256>::new(&um);
379         hmac.input(&packet.encode()[32..]);
380         packet.hmac = Hmac::from_engine(hmac).into_inner();
381
382         packet
383 }
384
385 #[cfg(test)]
386 pub(super) fn build_first_hop_failure_packet(shared_secret: &[u8], failure_type: u16, failure_data: &[u8]) -> msgs::OnionErrorPacket {
387         let failure_packet = build_failure_packet(shared_secret, failure_type, failure_data);
388         encrypt_failure_packet(shared_secret, &failure_packet.encode()[..])
389 }
390
391 /// Process failure we got back from upstream on a payment we sent (implying htlc_source is an
392 /// OutboundRoute).
393 /// Returns update, a boolean indicating that the payment itself failed, the short channel id of
394 /// the responsible channel, and the error code.
395 #[inline]
396 pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(secp_ctx: &Secp256k1<T>, logger: &L, htlc_source: &HTLCSource, mut packet_decrypted: Vec<u8>) -> (Option<NetworkUpdate>, Option<u64>, bool, Option<u16>, Option<Vec<u8>>) where L::Target: Logger {
397         if let &HTLCSource::OutboundRoute { ref path, ref session_priv, ref first_hop_htlc_msat, .. } = htlc_source {
398                 let mut res = None;
399                 let mut htlc_msat = *first_hop_htlc_msat;
400                 let mut error_code_ret = None;
401                 let mut error_packet_ret = None;
402                 let mut is_from_final_node = false;
403
404                 // Handle packed channel/node updates for passing back for the route handler
405                 construct_onion_keys_callback(secp_ctx, path, session_priv, |shared_secret, _, _, route_hop, route_hop_idx| {
406                         if res.is_some() { return; }
407
408                         let amt_to_forward = htlc_msat - route_hop.fee_msat;
409                         htlc_msat = amt_to_forward;
410
411                         let ammag = gen_ammag_from_shared_secret(shared_secret.as_ref());
412
413                         let mut decryption_tmp = Vec::with_capacity(packet_decrypted.len());
414                         decryption_tmp.resize(packet_decrypted.len(), 0);
415                         let mut chacha = ChaCha20::new(&ammag, &[0u8; 8]);
416                         chacha.process(&packet_decrypted, &mut decryption_tmp[..]);
417                         packet_decrypted = decryption_tmp;
418
419                         // The failing hop includes either the inbound channel to the recipient or the outbound
420                         // channel from the current hop (i.e., the next hop's inbound channel).
421                         is_from_final_node = route_hop_idx + 1 == path.len();
422                         let failing_route_hop = if is_from_final_node { route_hop } else { &path[route_hop_idx + 1] };
423
424                         if let Ok(err_packet) = msgs::DecodedOnionErrorPacket::read(&mut Cursor::new(&packet_decrypted)) {
425                                 let um = gen_um_from_shared_secret(shared_secret.as_ref());
426                                 let mut hmac = HmacEngine::<Sha256>::new(&um);
427                                 hmac.input(&err_packet.encode()[32..]);
428
429                                 if fixed_time_eq(&Hmac::from_engine(hmac).into_inner(), &err_packet.hmac) {
430                                         if let Some(error_code_slice) = err_packet.failuremsg.get(0..2) {
431                                                 const BADONION: u16 = 0x8000;
432                                                 const PERM: u16 = 0x4000;
433                                                 const NODE: u16 = 0x2000;
434                                                 const UPDATE: u16 = 0x1000;
435
436                                                 let error_code = u16::from_be_bytes(error_code_slice.try_into().expect("len is 2"));
437                                                 error_code_ret = Some(error_code);
438                                                 error_packet_ret = Some(err_packet.failuremsg[2..].to_vec());
439
440                                                 let (debug_field, debug_field_size) = errors::get_onion_debug_field(error_code);
441
442                                                 // indicate that payment parameter has failed and no need to
443                                                 // update Route object
444                                                 let payment_failed = match error_code & 0xff {
445                                                         15|16|17|18|19|23 => true,
446                                                         _ => false,
447                                                 } && is_from_final_node; // PERM bit observed below even if this error is from the intermediate nodes
448
449                                                 let mut network_update = None;
450                                                 let mut short_channel_id = None;
451
452                                                 if error_code & BADONION == BADONION {
453                                                         // If the error code has the BADONION bit set, always blame the channel
454                                                         // from the node "originating" the error to its next hop. The
455                                                         // "originator" is ultimately actually claiming that its counterparty
456                                                         // is the one who is failing the HTLC.
457                                                         // If the "originator" here isn't lying we should really mark the
458                                                         // next-hop node as failed entirely, but we can't be confident in that,
459                                                         // as it would allow any node to get us to completely ban one of its
460                                                         // counterparties. Instead, we simply remove the channel in question.
461                                                         network_update = Some(NetworkUpdate::ChannelFailure {
462                                                                 short_channel_id: failing_route_hop.short_channel_id,
463                                                                 is_permanent: true,
464                                                         });
465                                                 } else if error_code & NODE == NODE {
466                                                         let is_permanent = error_code & PERM == PERM;
467                                                         network_update = Some(NetworkUpdate::NodeFailure { node_id: route_hop.pubkey, is_permanent });
468                                                         short_channel_id = Some(route_hop.short_channel_id);
469                                                 } else if error_code & PERM == PERM {
470                                                         if !payment_failed {
471                                                                 network_update = Some(NetworkUpdate::ChannelFailure {
472                                                                         short_channel_id: failing_route_hop.short_channel_id,
473                                                                         is_permanent: true,
474                                                                 });
475                                                                 short_channel_id = Some(failing_route_hop.short_channel_id);
476                                                         }
477                                                 } else if error_code & UPDATE == UPDATE {
478                                                         if let Some(update_len_slice) = err_packet.failuremsg.get(debug_field_size+2..debug_field_size+4) {
479                                                                 let update_len = u16::from_be_bytes(update_len_slice.try_into().expect("len is 2")) as usize;
480                                                                 if let Some(mut update_slice) = err_packet.failuremsg.get(debug_field_size + 4..debug_field_size + 4 + update_len) {
481                                                                         // Historically, the BOLTs were unclear if the message type
482                                                                         // bytes should be included here or not. The BOLTs have now
483                                                                         // been updated to indicate that they *are* included, but many
484                                                                         // nodes still send messages without the type bytes, so we
485                                                                         // support both here.
486                                                                         // TODO: Switch to hard require the type prefix, as the current
487                                                                         // permissiveness introduces the (although small) possibility
488                                                                         // that we fail to decode legitimate channel updates that
489                                                                         // happen to start with ChannelUpdate::TYPE, i.e., [0x01, 0x02].
490                                                                         if update_slice.len() > 2 && update_slice[0..2] == msgs::ChannelUpdate::TYPE.to_be_bytes() {
491                                                                                 update_slice = &update_slice[2..];
492                                                                         } else {
493                                                                                 log_trace!(logger, "Failure provided features a channel update without type prefix. Deprecated, but allowing for now.");
494                                                                         }
495                                                                         if let Ok(chan_update) = msgs::ChannelUpdate::read(&mut Cursor::new(&update_slice)) {
496                                                                                 // if channel_update should NOT have caused the failure:
497                                                                                 // MAY treat the channel_update as invalid.
498                                                                                 let is_chan_update_invalid = match error_code & 0xff {
499                                                                                         7 => false,
500                                                                                         11 => amt_to_forward > chan_update.contents.htlc_minimum_msat,
501                                                                                         12 => amt_to_forward
502                                                                                                 .checked_mul(chan_update.contents.fee_proportional_millionths as u64)
503                                                                                                 .map(|prop_fee| prop_fee / 1_000_000)
504                                                                                                 .and_then(|prop_fee| prop_fee.checked_add(chan_update.contents.fee_base_msat as u64))
505                                                                                                 .map(|fee_msats| route_hop.fee_msat >= fee_msats)
506                                                                                                 .unwrap_or(false),
507                                                                                         13 => route_hop.cltv_expiry_delta as u16 >= chan_update.contents.cltv_expiry_delta,
508                                                                                         14 => false, // expiry_too_soon; always valid?
509                                                                                         20 => chan_update.contents.flags & 2 == 0,
510                                                                                         _ => false, // unknown error code; take channel_update as valid
511                                                                                 };
512                                                                                 if is_chan_update_invalid {
513                                                                                         // This probably indicates the node which forwarded
514                                                                                         // to the node in question corrupted something.
515                                                                                         network_update = Some(NetworkUpdate::ChannelFailure {
516                                                                                                 short_channel_id: route_hop.short_channel_id,
517                                                                                                 is_permanent: true,
518                                                                                         });
519                                                                                 } else {
520                                                                                         // Make sure the ChannelUpdate contains the expected
521                                                                                         // short channel id.
522                                                                                         if failing_route_hop.short_channel_id == chan_update.contents.short_channel_id {
523                                                                                                 short_channel_id = Some(failing_route_hop.short_channel_id);
524                                                                                         } else {
525                                                                                                 log_info!(logger, "Node provided a channel_update for which it was not authoritative, ignoring.");
526                                                                                         }
527                                                                                         network_update = Some(NetworkUpdate::ChannelUpdateMessage {
528                                                                                                 msg: chan_update,
529                                                                                         })
530                                                                                 };
531                                                                         }
532                                                                 }
533                                                         }
534                                                         if network_update.is_none() {
535                                                                 // They provided an UPDATE which was obviously bogus, not worth
536                                                                 // trying to relay through them anymore.
537                                                                 network_update = Some(NetworkUpdate::NodeFailure {
538                                                                         node_id: route_hop.pubkey,
539                                                                         is_permanent: true,
540                                                                 });
541                                                         }
542                                                         if short_channel_id.is_none() {
543                                                                 short_channel_id = Some(route_hop.short_channel_id);
544                                                         }
545                                                 } else if payment_failed {
546                                                         // Only blame the hop when a value in the HTLC doesn't match the
547                                                         // corresponding value in the onion.
548                                                         short_channel_id = match error_code & 0xff {
549                                                                 18|19 => Some(route_hop.short_channel_id),
550                                                                 _ => None,
551                                                         };
552                                                 } else {
553                                                         // We can't understand their error messages and they failed to
554                                                         // forward...they probably can't understand our forwards so its
555                                                         // really not worth trying any further.
556                                                         network_update = Some(NetworkUpdate::NodeFailure {
557                                                                 node_id: route_hop.pubkey,
558                                                                 is_permanent: true,
559                                                         });
560                                                         short_channel_id = Some(route_hop.short_channel_id);
561                                                 }
562
563                                                 res = Some((network_update, short_channel_id, !(error_code & PERM == PERM && is_from_final_node)));
564
565                                                 let (description, title) = errors::get_onion_error_description(error_code);
566                                                 if debug_field_size > 0 && err_packet.failuremsg.len() >= 4 + debug_field_size {
567                                                         log_info!(logger, "Onion Error[from {}: {}({:#x}) {}({})] {}", route_hop.pubkey, title, error_code, debug_field, log_bytes!(&err_packet.failuremsg[4..4+debug_field_size]), description);
568                                                 }
569                                                 else {
570                                                         log_info!(logger, "Onion Error[from {}: {}({:#x})] {}", route_hop.pubkey, title, error_code, description);
571                                                 }
572                                         } else {
573                                                 // Useless packet that we can't use but it passed HMAC, so it
574                                                 // definitely came from the peer in question
575                                                 let network_update = Some(NetworkUpdate::NodeFailure {
576                                                         node_id: route_hop.pubkey,
577                                                         is_permanent: true,
578                                                 });
579                                                 let short_channel_id = Some(route_hop.short_channel_id);
580                                                 res = Some((network_update, short_channel_id, !is_from_final_node));
581                                         }
582                                 }
583                         }
584                 }).expect("Route that we sent via spontaneously grew invalid keys in the middle of it?");
585                 if let Some((channel_update, short_channel_id, payment_retryable)) = res {
586                         (channel_update, short_channel_id, payment_retryable, error_code_ret, error_packet_ret)
587                 } else {
588                         // only not set either packet unparseable or hmac does not match with any
589                         // payment not retryable only when garbage is from the final node
590                         (None, None, !is_from_final_node, None, None)
591                 }
592         } else { unreachable!(); }
593 }
594
595 #[derive(Clone)] // See Channel::revoke_and_ack for why, tl;dr: Rust bug
596 pub(super) struct HTLCFailReason(HTLCFailReasonRepr);
597
598 #[derive(Clone)] // See Channel::revoke_and_ack for why, tl;dr: Rust bug
599 enum HTLCFailReasonRepr {
600         LightningError {
601                 err: msgs::OnionErrorPacket,
602         },
603         Reason {
604                 failure_code: u16,
605                 data: Vec<u8>,
606         }
607 }
608
609 impl core::fmt::Debug for HTLCFailReason {
610         fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
611                 match self.0 {
612                         HTLCFailReasonRepr::Reason { ref failure_code, .. } => {
613                                 write!(f, "HTLC error code {}", failure_code)
614                         },
615                         HTLCFailReasonRepr::LightningError { .. } => {
616                                 write!(f, "pre-built LightningError")
617                         }
618                 }
619         }
620 }
621
622 impl Writeable for HTLCFailReason {
623         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), crate::io::Error> {
624                 self.0.write(writer)
625         }
626 }
627 impl Readable for HTLCFailReason {
628         fn read<R: Read>(reader: &mut R) -> Result<Self, msgs::DecodeError> {
629                 Ok(Self(Readable::read(reader)?))
630         }
631 }
632
633 impl_writeable_tlv_based_enum!(HTLCFailReasonRepr,
634         (0, LightningError) => {
635                 (0, err, required),
636         },
637         (1, Reason) => {
638                 (0, failure_code, required),
639                 (2, data, vec_type),
640         },
641 ;);
642
643 impl HTLCFailReason {
644         pub(super) fn reason(failure_code: u16, data: Vec<u8>) -> Self {
645                 const BADONION: u16 = 0x8000;
646                 const PERM: u16 = 0x4000;
647                 const NODE: u16 = 0x2000;
648                 const UPDATE: u16 = 0x1000;
649
650                      if failure_code == 1  | PERM { debug_assert!(data.is_empty()) }
651                 else if failure_code == 2  | NODE { debug_assert!(data.is_empty()) }
652                 else if failure_code == 2  | PERM | NODE { debug_assert!(data.is_empty()) }
653                 else if failure_code == 3  | PERM | NODE { debug_assert!(data.is_empty()) }
654                 else if failure_code == 4  | BADONION | PERM { debug_assert_eq!(data.len(), 32) }
655                 else if failure_code == 5  | BADONION | PERM { debug_assert_eq!(data.len(), 32) }
656                 else if failure_code == 6  | BADONION | PERM { debug_assert_eq!(data.len(), 32) }
657                 else if failure_code == 7  | UPDATE {
658                         debug_assert_eq!(data.len() - 2, u16::from_be_bytes(data[0..2].try_into().unwrap()) as usize) }
659                 else if failure_code == 8  | PERM { debug_assert!(data.is_empty()) }
660                 else if failure_code == 9  | PERM { debug_assert!(data.is_empty()) }
661                 else if failure_code == 10 | PERM { debug_assert!(data.is_empty()) }
662                 else if failure_code == 11 | UPDATE {
663                         debug_assert_eq!(data.len() - 2 - 8, u16::from_be_bytes(data[8..10].try_into().unwrap()) as usize) }
664                 else if failure_code == 12 | UPDATE {
665                         debug_assert_eq!(data.len() - 2 - 8, u16::from_be_bytes(data[8..10].try_into().unwrap()) as usize) }
666                 else if failure_code == 13 | UPDATE {
667                         debug_assert_eq!(data.len() - 2 - 4, u16::from_be_bytes(data[4..6].try_into().unwrap()) as usize) }
668                 else if failure_code == 14 | UPDATE {
669                         debug_assert_eq!(data.len() - 2, u16::from_be_bytes(data[0..2].try_into().unwrap()) as usize) }
670                 else if failure_code == 15 | PERM { debug_assert_eq!(data.len(), 12) }
671                 else if failure_code == 18 { debug_assert_eq!(data.len(), 4) }
672                 else if failure_code == 19 { debug_assert_eq!(data.len(), 8) }
673                 else if failure_code == 20 | UPDATE {
674                         debug_assert_eq!(data.len() - 2 - 2, u16::from_be_bytes(data[2..4].try_into().unwrap()) as usize) }
675                 else if failure_code == 21 { debug_assert!(data.is_empty()) }
676                 else if failure_code == 22 | PERM { debug_assert!(data.len() <= 11) }
677                 else if failure_code == 23 { debug_assert!(data.is_empty()) }
678                 else if failure_code & BADONION != 0 {
679                         // We set some bogus BADONION failure codes in test, so ignore unknown ones.
680                 }
681                 else { debug_assert!(false, "Unknown failure code: {}", failure_code) }
682
683                 Self(HTLCFailReasonRepr::Reason { failure_code, data })
684         }
685
686         pub(super) fn from_failure_code(failure_code: u16) -> Self {
687                 Self::reason(failure_code, Vec::new())
688         }
689
690         pub(super) fn from_msg(msg: &msgs::UpdateFailHTLC) -> Self {
691                 Self(HTLCFailReasonRepr::LightningError { err: msg.reason.clone() })
692         }
693
694         pub(super) fn get_encrypted_failure_packet(&self, incoming_packet_shared_secret: &[u8; 32], phantom_shared_secret: &Option<[u8; 32]>)
695         -> msgs::OnionErrorPacket {
696                 match self.0 {
697                         HTLCFailReasonRepr::Reason { ref failure_code, ref data } => {
698                                 if let Some(phantom_ss) = phantom_shared_secret {
699                                         let phantom_packet = build_failure_packet(phantom_ss, *failure_code, &data[..]).encode();
700                                         let encrypted_phantom_packet = encrypt_failure_packet(phantom_ss, &phantom_packet);
701                                         encrypt_failure_packet(incoming_packet_shared_secret, &encrypted_phantom_packet.data[..])
702                                 } else {
703                                         let packet = build_failure_packet(incoming_packet_shared_secret, *failure_code, &data[..]).encode();
704                                         encrypt_failure_packet(incoming_packet_shared_secret, &packet)
705                                 }
706                         },
707                         HTLCFailReasonRepr::LightningError { ref err } => {
708                                 encrypt_failure_packet(incoming_packet_shared_secret, &err.data)
709                         }
710                 }
711         }
712
713         pub(super) fn decode_onion_failure<T: secp256k1::Signing, L: Deref>(
714                 &self, secp_ctx: &Secp256k1<T>, logger: &L, htlc_source: &HTLCSource
715         ) -> (Option<NetworkUpdate>, Option<u64>, bool, Option<u16>, Option<Vec<u8>>)
716         where L::Target: Logger {
717                 match self.0 {
718                         HTLCFailReasonRepr::LightningError { ref err } => {
719                                 process_onion_failure(secp_ctx, logger, &htlc_source, err.data.clone())
720                         },
721                         HTLCFailReasonRepr::Reason { ref failure_code, ref data, .. } => {
722                                 // we get a fail_malformed_htlc from the first hop
723                                 // TODO: We'd like to generate a NetworkUpdate for temporary
724                                 // failures here, but that would be insufficient as find_route
725                                 // generally ignores its view of our own channels as we provide them via
726                                 // ChannelDetails.
727                                 if let &HTLCSource::OutboundRoute { ref path, .. } = htlc_source {
728                                         (None, Some(path.first().unwrap().short_channel_id), true, Some(*failure_code), Some(data.clone()))
729                                 } else { unreachable!(); }
730                         }
731                 }
732         }
733 }
734
735 /// Allows `decode_next_hop` to return the next hop packet bytes for either payments or onion
736 /// message forwards.
737 pub(crate) trait NextPacketBytes: AsMut<[u8]> {
738         fn new(len: usize) -> Self;
739 }
740
741 impl NextPacketBytes for FixedSizeOnionPacket {
742         fn new(_len: usize) -> Self  {
743                 Self([0 as u8; ONION_DATA_LEN])
744         }
745 }
746
747 impl NextPacketBytes for Vec<u8> {
748         fn new(len: usize) -> Self {
749                 vec![0 as u8; len]
750         }
751 }
752
753 /// Data decrypted from a payment's onion payload.
754 pub(crate) enum Hop {
755         /// This onion payload was for us, not for forwarding to a next-hop. Contains information for
756         /// verifying the incoming payment.
757         Receive(msgs::OnionHopData),
758         /// This onion payload needs to be forwarded to a next-hop.
759         Forward {
760                 /// Onion payload data used in forwarding the payment.
761                 next_hop_data: msgs::OnionHopData,
762                 /// HMAC of the next hop's onion packet.
763                 next_hop_hmac: [u8; 32],
764                 /// Bytes of the onion packet we're forwarding.
765                 new_packet_bytes: [u8; ONION_DATA_LEN],
766         },
767 }
768
769 /// Error returned when we fail to decode the onion packet.
770 #[derive(Debug)]
771 pub(crate) enum OnionDecodeErr {
772         /// The HMAC of the onion packet did not match the hop data.
773         Malformed {
774                 err_msg: &'static str,
775                 err_code: u16,
776         },
777         /// We failed to decode the onion payload.
778         Relay {
779                 err_msg: &'static str,
780                 err_code: u16,
781         },
782 }
783
784 pub(crate) fn decode_next_payment_hop(shared_secret: [u8; 32], hop_data: &[u8], hmac_bytes: [u8; 32], payment_hash: PaymentHash) -> Result<Hop, OnionDecodeErr> {
785         match decode_next_hop(shared_secret, hop_data, hmac_bytes, Some(payment_hash), ()) {
786                 Ok((next_hop_data, None)) => Ok(Hop::Receive(next_hop_data)),
787                 Ok((next_hop_data, Some((next_hop_hmac, FixedSizeOnionPacket(new_packet_bytes))))) => {
788                         Ok(Hop::Forward {
789                                 next_hop_data,
790                                 next_hop_hmac,
791                                 new_packet_bytes
792                         })
793                 },
794                 Err(e) => Err(e),
795         }
796 }
797
798 pub(crate) fn decode_next_untagged_hop<T, R: ReadableArgs<T>, N: NextPacketBytes>(shared_secret: [u8; 32], hop_data: &[u8], hmac_bytes: [u8; 32], read_args: T) -> Result<(R, Option<([u8; 32], N)>), OnionDecodeErr> {
799         decode_next_hop(shared_secret, hop_data, hmac_bytes, None, read_args)
800 }
801
802 fn decode_next_hop<T, R: ReadableArgs<T>, N: NextPacketBytes>(shared_secret: [u8; 32], hop_data: &[u8], hmac_bytes: [u8; 32], payment_hash: Option<PaymentHash>, read_args: T) -> Result<(R, Option<([u8; 32], N)>), OnionDecodeErr> {
803         let (rho, mu) = gen_rho_mu_from_shared_secret(&shared_secret);
804         let mut hmac = HmacEngine::<Sha256>::new(&mu);
805         hmac.input(hop_data);
806         if let Some(tag) = payment_hash {
807                 hmac.input(&tag.0[..]);
808         }
809         if !fixed_time_eq(&Hmac::from_engine(hmac).into_inner(), &hmac_bytes) {
810                 return Err(OnionDecodeErr::Malformed {
811                         err_msg: "HMAC Check failed",
812                         err_code: 0x8000 | 0x4000 | 5,
813                 });
814         }
815
816         let mut chacha = ChaCha20::new(&rho, &[0u8; 8]);
817         let mut chacha_stream = ChaChaReader { chacha: &mut chacha, read: Cursor::new(&hop_data[..]) };
818         match R::read(&mut chacha_stream, read_args) {
819                 Err(err) => {
820                         let error_code = match err {
821                                 msgs::DecodeError::UnknownVersion => 0x4000 | 1, // unknown realm byte
822                                 msgs::DecodeError::UnknownRequiredFeature|
823                                 msgs::DecodeError::InvalidValue|
824                                 msgs::DecodeError::ShortRead => 0x4000 | 22, // invalid_onion_payload
825                                 _ => 0x2000 | 2, // Should never happen
826                         };
827                         return Err(OnionDecodeErr::Relay {
828                                 err_msg: "Unable to decode our hop data",
829                                 err_code: error_code,
830                         });
831                 },
832                 Ok(msg) => {
833                         let mut hmac = [0; 32];
834                         if let Err(_) = chacha_stream.read_exact(&mut hmac[..]) {
835                                 return Err(OnionDecodeErr::Relay {
836                                         err_msg: "Unable to decode our hop data",
837                                         err_code: 0x4000 | 22,
838                                 });
839                         }
840                         if hmac == [0; 32] {
841                                 #[cfg(test)]
842                                 {
843                                         // In tests, make sure that the initial onion packet data is, at least, non-0.
844                                         // We could do some fancy randomness test here, but, ehh, whatever.
845                                         // This checks for the issue where you can calculate the path length given the
846                                         // onion data as all the path entries that the originator sent will be here
847                                         // as-is (and were originally 0s).
848                                         // Of course reverse path calculation is still pretty easy given naive routing
849                                         // algorithms, but this fixes the most-obvious case.
850                                         let mut next_bytes = [0; 32];
851                                         chacha_stream.read_exact(&mut next_bytes).unwrap();
852                                         assert_ne!(next_bytes[..], [0; 32][..]);
853                                         chacha_stream.read_exact(&mut next_bytes).unwrap();
854                                         assert_ne!(next_bytes[..], [0; 32][..]);
855                                 }
856                                 return Ok((msg, None)); // We are the final destination for this packet
857                         } else {
858                                 let mut new_packet_bytes = N::new(hop_data.len());
859                                 let read_pos = hop_data.len() - chacha_stream.read.position() as usize;
860                                 chacha_stream.read_exact(&mut new_packet_bytes.as_mut()[..read_pos]).unwrap();
861                                 #[cfg(debug_assertions)]
862                                 {
863                                         // Check two things:
864                                         // a) that the behavior of our stream here will return Ok(0) even if the TLV
865                                         //    read above emptied out our buffer and the unwrap() wont needlessly panic
866                                         // b) that we didn't somehow magically end up with extra data.
867                                         let mut t = [0; 1];
868                                         debug_assert!(chacha_stream.read(&mut t).unwrap() == 0);
869                                 }
870                                 // Once we've emptied the set of bytes our peer gave us, encrypt 0 bytes until we
871                                 // fill the onion hop data we'll forward to our next-hop peer.
872                                 chacha_stream.chacha.process_in_place(&mut new_packet_bytes.as_mut()[read_pos..]);
873                                 return Ok((msg, Some((hmac, new_packet_bytes)))) // This packet needs forwarding
874                         }
875                 },
876         }
877 }
878
879 #[cfg(test)]
880 mod tests {
881         use crate::io;
882         use crate::prelude::*;
883         use crate::ln::PaymentHash;
884         use crate::ln::features::{ChannelFeatures, NodeFeatures};
885         use crate::routing::router::{Route, RouteHop};
886         use crate::ln::msgs;
887         use crate::util::ser::{Writeable, Writer, VecWriter};
888
889         use hex;
890
891         use bitcoin::secp256k1::Secp256k1;
892         use bitcoin::secp256k1::{PublicKey,SecretKey};
893
894         use super::OnionKeys;
895
896         fn get_test_session_key() -> SecretKey {
897                 SecretKey::from_slice(&hex::decode("4141414141414141414141414141414141414141414141414141414141414141").unwrap()[..]).unwrap()
898         }
899
900         fn build_test_onion_keys() -> Vec<OnionKeys> {
901                 // Keys from BOLT 4, used in both test vector tests
902                 let secp_ctx = Secp256k1::new();
903
904                 let route = Route {
905                         paths: vec![vec![
906                                         RouteHop {
907                                                 pubkey: PublicKey::from_slice(&hex::decode("02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619").unwrap()[..]).unwrap(),
908                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
909                                                 short_channel_id: 0, fee_msat: 0, cltv_expiry_delta: 0 // We fill in the payloads manually instead of generating them from RouteHops.
910                                         },
911                                         RouteHop {
912                                                 pubkey: PublicKey::from_slice(&hex::decode("0324653eac434488002cc06bbfb7f10fe18991e35f9fe4302dbea6d2353dc0ab1c").unwrap()[..]).unwrap(),
913                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
914                                                 short_channel_id: 0, fee_msat: 0, cltv_expiry_delta: 0 // We fill in the payloads manually instead of generating them from RouteHops.
915                                         },
916                                         RouteHop {
917                                                 pubkey: PublicKey::from_slice(&hex::decode("027f31ebc5462c1fdce1b737ecff52d37d75dea43ce11c74d25aa297165faa2007").unwrap()[..]).unwrap(),
918                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
919                                                 short_channel_id: 0, fee_msat: 0, cltv_expiry_delta: 0 // We fill in the payloads manually instead of generating them from RouteHops.
920                                         },
921                                         RouteHop {
922                                                 pubkey: PublicKey::from_slice(&hex::decode("032c0b7cf95324a07d05398b240174dc0c2be444d96b159aa6c7f7b1e668680991").unwrap()[..]).unwrap(),
923                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
924                                                 short_channel_id: 0, fee_msat: 0, cltv_expiry_delta: 0 // We fill in the payloads manually instead of generating them from RouteHops.
925                                         },
926                                         RouteHop {
927                                                 pubkey: PublicKey::from_slice(&hex::decode("02edabbd16b41c8371b92ef2f04c1185b4f03b6dcd52ba9b78d9d7c89c8f221145").unwrap()[..]).unwrap(),
928                                                 channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
929                                                 short_channel_id: 0, fee_msat: 0, cltv_expiry_delta: 0 // We fill in the payloads manually instead of generating them from RouteHops.
930                                         },
931                         ]],
932                         payment_params: None,
933                 };
934
935                 let onion_keys = super::construct_onion_keys(&secp_ctx, &route.paths[0], &get_test_session_key()).unwrap();
936                 assert_eq!(onion_keys.len(), route.paths[0].len());
937                 onion_keys
938         }
939
940         #[test]
941         fn onion_vectors() {
942                 let onion_keys = build_test_onion_keys();
943
944                 // Test generation of ephemeral keys and secrets. These values used to be part of the BOLT4
945                 // test vectors, but have since been removed. We keep them as they provide test coverage.
946                 assert_eq!(onion_keys[0].shared_secret.secret_bytes(), hex::decode("53eb63ea8a3fec3b3cd433b85cd62a4b145e1dda09391b348c4e1cd36a03ea66").unwrap()[..]);
947                 assert_eq!(onion_keys[0].blinding_factor[..], hex::decode("2ec2e5da605776054187180343287683aa6a51b4b1c04d6dd49c45d8cffb3c36").unwrap()[..]);
948                 assert_eq!(onion_keys[0].ephemeral_pubkey.serialize()[..], hex::decode("02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619").unwrap()[..]);
949                 assert_eq!(onion_keys[0].rho, hex::decode("ce496ec94def95aadd4bec15cdb41a740c9f2b62347c4917325fcc6fb0453986").unwrap()[..]);
950                 assert_eq!(onion_keys[0].mu, hex::decode("b57061dc6d0a2b9f261ac410c8b26d64ac5506cbba30267a649c28c179400eba").unwrap()[..]);
951
952                 assert_eq!(onion_keys[1].shared_secret.secret_bytes(), hex::decode("a6519e98832a0b179f62123b3567c106db99ee37bef036e783263602f3488fae").unwrap()[..]);
953                 assert_eq!(onion_keys[1].blinding_factor[..], hex::decode("bf66c28bc22e598cfd574a1931a2bafbca09163df2261e6d0056b2610dab938f").unwrap()[..]);
954                 assert_eq!(onion_keys[1].ephemeral_pubkey.serialize()[..], hex::decode("028f9438bfbf7feac2e108d677e3a82da596be706cc1cf342b75c7b7e22bf4e6e2").unwrap()[..]);
955                 assert_eq!(onion_keys[1].rho, hex::decode("450ffcabc6449094918ebe13d4f03e433d20a3d28a768203337bc40b6e4b2c59").unwrap()[..]);
956                 assert_eq!(onion_keys[1].mu, hex::decode("05ed2b4a3fb023c2ff5dd6ed4b9b6ea7383f5cfe9d59c11d121ec2c81ca2eea9").unwrap()[..]);
957
958                 assert_eq!(onion_keys[2].shared_secret.secret_bytes(), hex::decode("3a6b412548762f0dbccce5c7ae7bb8147d1caf9b5471c34120b30bc9c04891cc").unwrap()[..]);
959                 assert_eq!(onion_keys[2].blinding_factor[..], hex::decode("a1f2dadd184eb1627049673f18c6325814384facdee5bfd935d9cb031a1698a5").unwrap()[..]);
960                 assert_eq!(onion_keys[2].ephemeral_pubkey.serialize()[..], hex::decode("03bfd8225241ea71cd0843db7709f4c222f62ff2d4516fd38b39914ab6b83e0da0").unwrap()[..]);
961                 assert_eq!(onion_keys[2].rho, hex::decode("11bf5c4f960239cb37833936aa3d02cea82c0f39fd35f566109c41f9eac8deea").unwrap()[..]);
962                 assert_eq!(onion_keys[2].mu, hex::decode("caafe2820fa00eb2eeb78695ae452eba38f5a53ed6d53518c5c6edf76f3f5b78").unwrap()[..]);
963
964                 assert_eq!(onion_keys[3].shared_secret.secret_bytes(), hex::decode("21e13c2d7cfe7e18836df50872466117a295783ab8aab0e7ecc8c725503ad02d").unwrap()[..]);
965                 assert_eq!(onion_keys[3].blinding_factor[..], hex::decode("7cfe0b699f35525029ae0fa437c69d0f20f7ed4e3916133f9cacbb13c82ff262").unwrap()[..]);
966                 assert_eq!(onion_keys[3].ephemeral_pubkey.serialize()[..], hex::decode("031dde6926381289671300239ea8e57ffaf9bebd05b9a5b95beaf07af05cd43595").unwrap()[..]);
967                 assert_eq!(onion_keys[3].rho, hex::decode("cbe784ab745c13ff5cffc2fbe3e84424aa0fd669b8ead4ee562901a4a4e89e9e").unwrap()[..]);
968                 assert_eq!(onion_keys[3].mu, hex::decode("5052aa1b3d9f0655a0932e50d42f0c9ba0705142c25d225515c45f47c0036ee9").unwrap()[..]);
969
970                 assert_eq!(onion_keys[4].shared_secret.secret_bytes(), hex::decode("b5756b9b542727dbafc6765a49488b023a725d631af688fc031217e90770c328").unwrap()[..]);
971                 assert_eq!(onion_keys[4].blinding_factor[..], hex::decode("c96e00dddaf57e7edcd4fb5954be5b65b09f17cb6d20651b4e90315be5779205").unwrap()[..]);
972                 assert_eq!(onion_keys[4].ephemeral_pubkey.serialize()[..], hex::decode("03a214ebd875aab6ddfd77f22c5e7311d7f77f17a169e599f157bbcdae8bf071f4").unwrap()[..]);
973                 assert_eq!(onion_keys[4].rho, hex::decode("034e18b8cc718e8af6339106e706c52d8df89e2b1f7e9142d996acf88df8799b").unwrap()[..]);
974                 assert_eq!(onion_keys[4].mu, hex::decode("8e45e5c61c2b24cb6382444db6698727afb063adecd72aada233d4bf273d975a").unwrap()[..]);
975
976                 // Packet creation test vectors from BOLT 4 (see
977                 // https://github.com/lightning/bolts/blob/16973e2b857e853308cafd59e42fa830d75b1642/bolt04/onion-test.json).
978                 // Note that we represent the test vector payloads 2 and 5 through RawOnionHopData::data
979                 // with raw hex instead of our in-memory enums, as the payloads contains custom types, and
980                 // we have no way of representing that with our enums.
981                 let payloads = vec!(
982                         RawOnionHopData::new(msgs::OnionHopData {
983                                 format: msgs::OnionHopDataFormat::NonFinalNode {
984                                         short_channel_id: 1,
985                                 },
986                                 amt_to_forward: 15000,
987                                 outgoing_cltv_value: 1500,
988                         }),
989                         /*
990                         The second payload is represented by raw hex as it contains custom type data. Content:
991                         1. length "52" (payload_length 82).
992
993                         The first part of the payload has the `NonFinalNode` format, with content as follows:
994                         2. amt_to_forward "020236b0"
995                            02 (type amt_to_forward) 02 (length 2) 36b0 (value 14000)
996                         3. outgoing_cltv_value "04020578"
997                            04 (type outgoing_cltv_value) 02 (length 2) 0578 (value 1400)
998                         4. short_channel_id "06080000000000000002"
999                            06 (type short_channel_id) 08 (length 8) 0000000000000002 (value 2)
1000
1001                         The rest of the payload is custom type data:
1002                         5. custom_record "fd02013c0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f"
1003                         */
1004                         RawOnionHopData {
1005                                 data: hex::decode("52020236b00402057806080000000000000002fd02013c0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f").unwrap(),
1006                         },
1007                         RawOnionHopData::new(msgs::OnionHopData {
1008                                 format: msgs::OnionHopDataFormat::NonFinalNode {
1009                                         short_channel_id: 3,
1010                                 },
1011                                 amt_to_forward: 12500,
1012                                 outgoing_cltv_value: 1250,
1013                         }),
1014                         RawOnionHopData::new(msgs::OnionHopData {
1015                                 format: msgs::OnionHopDataFormat::NonFinalNode {
1016                                         short_channel_id: 4,
1017                                 },
1018                                 amt_to_forward: 10000,
1019                                 outgoing_cltv_value: 1000,
1020                         }),
1021                         /*
1022                         The fifth payload is represented by raw hex as it contains custom type data. Content:
1023                         1. length "fd0110" (payload_length 272).
1024
1025                         The first part of the payload has the `FinalNode` format, with content as follows:
1026                         1. amt_to_forward "02022710"
1027                            02 (type amt_to_forward) 02 (length 2) 2710 (value 10000)
1028                         2. outgoing_cltv_value "040203e8"
1029                            04 (type outgoing_cltv_value) 02 (length 2) 03e8 (value 1000)
1030                         3. payment_data "082224a33562c54507a9334e79f0dc4f17d407e6d7c61f0e2f3d0d38599502f617042710"
1031                            08 (type short_channel_id) 22 (length 34) 24a33562c54507a9334e79f0dc4f17d407e6d7c61f0e2f3d0d38599502f61704 (payment_secret) 2710 (total_msat value 10000)
1032
1033                         The rest of the payload is custom type data:
1034                         4. custom_record "fd012de02a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a"
1035                         */
1036                         RawOnionHopData {
1037                                 data: hex::decode("fd011002022710040203e8082224a33562c54507a9334e79f0dc4f17d407e6d7c61f0e2f3d0d38599502f617042710fd012de02a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a2a").unwrap(),
1038                         },
1039                 );
1040
1041                 // Verify that the serialized OnionHopDataFormat::NonFinalNode tlv payloads matches the test vectors
1042                 let mut w = VecWriter(Vec::new());
1043                 payloads[0].write(&mut w).unwrap();
1044                 let hop_1_serialized_payload = w.0;
1045                 let expected_serialized_hop_1_payload = &hex::decode("1202023a98040205dc06080000000000000001").unwrap()[..];
1046                 assert_eq!(hop_1_serialized_payload, expected_serialized_hop_1_payload);
1047
1048                 w = VecWriter(Vec::new());
1049                 payloads[2].write(&mut w).unwrap();
1050                 let hop_3_serialized_payload = w.0;
1051                 let expected_serialized_hop_3_payload = &hex::decode("12020230d4040204e206080000000000000003").unwrap()[..];
1052                 assert_eq!(hop_3_serialized_payload, expected_serialized_hop_3_payload);
1053
1054                 w = VecWriter(Vec::new());
1055                 payloads[3].write(&mut w).unwrap();
1056                 let hop_4_serialized_payload = w.0;
1057                 let expected_serialized_hop_4_payload = &hex::decode("1202022710040203e806080000000000000004").unwrap()[..];
1058                 assert_eq!(hop_4_serialized_payload, expected_serialized_hop_4_payload);
1059
1060                 let pad_keytype_seed = super::gen_pad_from_shared_secret(&get_test_session_key().secret_bytes());
1061
1062                 let packet: msgs::OnionPacket = super::construct_onion_packet_with_writable_hopdata::<_>(payloads, onion_keys, pad_keytype_seed, &PaymentHash([0x42; 32]));
1063
1064                 assert_eq!(packet.encode(), hex::decode("0002EEC7245D6B7D2CCB30380BFBE2A3648CD7A942653F5AA340EDCEA1F283686619F7F3416A5AA36DC7EEB3EC6D421E9615471AB870A33AC07FA5D5A51DF0A8823AABE3FEA3F90D387529D4F72837F9E687230371CCD8D263072206DBED0234F6505E21E282ABD8C0E4F5B9FF8042800BBAB065036EADD0149B37F27DDE664725A49866E052E809D2B0198AB9610FAA656BBF4EC516763A59F8F42C171B179166BA38958D4F51B39B3E98706E2D14A2DAFD6A5DF808093ABFCA5AEAACA16EDED5DB7D21FB0294DD1A163EDF0FB445D5C8D7D688D6DD9C541762BF5A5123BF9939D957FE648416E88F1B0928BFA034982B22548E1A4D922690EECF546275AFB233ACF4323974680779F1A964CFE687456035CC0FBA8A5428430B390F0057B6D1FE9A8875BFA89693EEB838CE59F09D207A503EE6F6299C92D6361BC335FCBF9B5CD44747AADCE2CE6069CFDC3D671DAEF9F8AE590CF93D957C9E873E9A1BC62D9640DC8FC39C14902D49A1C80239B6C5B7FD91D05878CBF5FFC7DB2569F47C43D6C0D27C438ABFF276E87364DEB8858A37E5A62C446AF95D8B786EAF0B5FCF78D98B41496794F8DCAAC4EEF34B2ACFB94C7E8C32A9E9866A8FA0B6F2A06F00A1CCDE569F97EEC05C803BA7500ACC96691D8898D73D8E6A47B8F43C3D5DE74458D20EDA61474C426359677001FBD75A74D7D5DB6CB4FEB83122F133206203E4E2D293F838BF8C8B3A29ACB321315100B87E80E0EDB272EE80FDA944E3FB6084ED4D7F7C7D21C69D9DA43D31A90B70693F9B0CC3EAC74C11AB8FF655905688916CFA4EF0BD04135F2E50B7C689A21D04E8E981E74C6058188B9B1F9DFC3EEC6838E9FFBCF22CE738D8A177C19318DFFEF090CEE67E12DE1A3E2A39F61247547BA5257489CBC11D7D91ED34617FCC42F7A9DA2E3CF31A94A210A1018143173913C38F60E62B24BF0D7518F38B5BAB3E6A1F8AEB35E31D6442C8ABB5178EFC892D2E787D79C6AD9E2FC271792983FA9955AC4D1D84A36C024071BC6E431B625519D556AF38185601F70E29035EA6A09C8B676C9D88CF7E05E0F17098B584C4168735940263F940033A220F40BE4C85344128B14BEB9E75696DB37014107801A59B13E89CD9D2258C169D523BE6D31552C44C82FF4BB18EC9F099F3BF0E5B1BB2BA9A87D7E26F98D294927B600B5529C47E04D98956677CBCEE8FA2B60F49776D8B8C367465B7C626DA53700684FB6C918EAD0EAB8360E4F60EDD25B4F43816A75ECF70F909301825B512469F8389D79402311D8AECB7B3EF8599E79485A4388D87744D899F7C47EE644361E17040A7958C8911BE6F463AB6A9B2AFACD688EC55EF517B38F1339EFC54487232798BB25522FF4572FF68567FE830F92F7B8113EFCE3E98C3FFFBAEDCE4FD8B50E41DA97C0C08E423A72689CC68E68F752A5E3A9003E64E35C957CA2E1C48BB6F64B05F56B70B575AD2F278D57850A7AD568C24A4D32A3D74B29F03DC125488BC7C637DA582357F40B0A52D16B3B40BB2C2315D03360BC24209E20972C200566BCF3BBE5C5B0AEDD83132A8A4D5B4242BA370B6D67D9B67EB01052D132C7866B9CB502E44796D9D356E4E3CB47CC527322CD24976FE7C9257A2864151A38E568EF7A79F10D6EF27CC04CE382347A2488B1F404FDBF407FE1CA1C9D0D5649E34800E25E18951C98CAE9F43555EEF65FEE1EA8F15828807366C3B612CD5753BF9FB8FCED08855F742CDDD6F765F74254F03186683D646E6F09AC2805586C7CF11998357CAFC5DF3F285329366F475130C928B2DCEBA4AA383758E7A9D20705C4BB9DB619E2992F608A1BA65DB254BB389468741D0502E2588AEB54390AC600C19AF5C8E61383FC1BEBE0029E4474051E4EF908828DB9CCA13277EF65DB3FD47CCC2179126AAEFB627719F421E20").unwrap());
1065         }
1066
1067         #[test]
1068         fn test_failure_packet_onion() {
1069                 // Returning Errors test vectors from BOLT 4
1070
1071                 let onion_keys = build_test_onion_keys();
1072                 let onion_error = super::build_failure_packet(onion_keys[4].shared_secret.as_ref(), 0x2002, &[0; 0]);
1073                 assert_eq!(onion_error.encode(), hex::decode("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").unwrap());
1074
1075                 let onion_packet_1 = super::encrypt_failure_packet(onion_keys[4].shared_secret.as_ref(), &onion_error.encode()[..]);
1076                 assert_eq!(onion_packet_1.data, hex::decode("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").unwrap());
1077
1078                 let onion_packet_2 = super::encrypt_failure_packet(onion_keys[3].shared_secret.as_ref(), &onion_packet_1.data[..]);
1079                 assert_eq!(onion_packet_2.data, hex::decode("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").unwrap());
1080
1081                 let onion_packet_3 = super::encrypt_failure_packet(onion_keys[2].shared_secret.as_ref(), &onion_packet_2.data[..]);
1082                 assert_eq!(onion_packet_3.data, hex::decode("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").unwrap());
1083
1084                 let onion_packet_4 = super::encrypt_failure_packet(onion_keys[1].shared_secret.as_ref(), &onion_packet_3.data[..]);
1085                 assert_eq!(onion_packet_4.data, hex::decode("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").unwrap());
1086
1087                 let onion_packet_5 = super::encrypt_failure_packet(onion_keys[0].shared_secret.as_ref(), &onion_packet_4.data[..]);
1088                 assert_eq!(onion_packet_5.data, hex::decode("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").unwrap());
1089         }
1090
1091         struct RawOnionHopData {
1092                 data: Vec<u8>
1093         }
1094         impl RawOnionHopData {
1095                 fn new(orig: msgs::OnionHopData) -> Self {
1096                         Self { data: orig.encode() }
1097                 }
1098         }
1099         impl Writeable for RawOnionHopData {
1100                 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
1101                         writer.write_all(&self.data[..])
1102                 }
1103         }
1104 }