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

   1 //! Utilities for channelmanager.rs
   2 //!
   3 //! Includes a public [`peel_payment_onion`] function for use by external projects or libraries.
   4
   5 use bitcoin::hashes::Hash;
   6 use bitcoin::hashes::sha256::Hash as Sha256;
   7 use bitcoin::secp256k1::{self, Secp256k1, PublicKey};
   8
   9 use crate::blinded_path;
  10 use crate::blinded_path::payment::{PaymentConstraints, PaymentRelay};
  11 use crate::chain::channelmonitor::{HTLC_FAIL_BACK_BUFFER, LATENCY_GRACE_PERIOD_BLOCKS};
  12 use crate::ln::PaymentHash;
  13 use crate::ln::channelmanager::{BlindedForward, CLTV_FAR_FAR_AWAY, HTLCFailureMsg, MIN_CLTV_EXPIRY_DELTA, PendingHTLCInfo, PendingHTLCRouting};
  14 use crate::ln::features::BlindedHopFeatures;
  15 use crate::ln::msgs;
  16 use crate::ln::onion_utils;
  17 use crate::ln::onion_utils::{HTLCFailReason, INVALID_ONION_BLINDING};
  18 use crate::sign::{NodeSigner, Recipient};
  19 use crate::util::logger::Logger;
  20
  21 use crate::prelude::*;
  22 use core::ops::Deref;
  23
  24 /// Invalid inbound onion payment.
  25 pub struct InboundOnionErr {
  26         /// BOLT 4 error code.
  27         pub err_code: u16,
  28         /// Data attached to this error.
  29         pub err_data: Vec<u8>,
  30         /// Error message text.
  31         pub msg: &'static str,
  32 }
  33
  34 fn check_blinded_forward(
  35         inbound_amt_msat: u64, inbound_cltv_expiry: u32, payment_relay: &PaymentRelay,
  36         payment_constraints: &PaymentConstraints, features: &BlindedHopFeatures
  37 ) -> Result<(u64, u32), ()> {
  38         let amt_to_forward = blinded_path::payment::amt_to_forward_msat(
  39                 inbound_amt_msat, payment_relay
  40         ).ok_or(())?;
  41         let outgoing_cltv_value = inbound_cltv_expiry.checked_sub(
  42                 payment_relay.cltv_expiry_delta as u32
  43         ).ok_or(())?;
  44         if inbound_amt_msat < payment_constraints.htlc_minimum_msat ||
  45                 outgoing_cltv_value > payment_constraints.max_cltv_expiry
  46                 { return Err(()) }
  47         if features.requires_unknown_bits_from(&BlindedHopFeatures::empty()) { return Err(()) }
  48         Ok((amt_to_forward, outgoing_cltv_value))
  49 }
  50
  51 pub(super) fn create_fwd_pending_htlc_info(
  52         msg: &msgs::UpdateAddHTLC, hop_data: msgs::InboundOnionPayload, hop_hmac: [u8; 32],
  53         new_packet_bytes: [u8; onion_utils::ONION_DATA_LEN], shared_secret: [u8; 32],
  54         next_packet_pubkey_opt: Option<Result<PublicKey, secp256k1::Error>>
  55 ) -> Result<PendingHTLCInfo, InboundOnionErr> {
  56         debug_assert!(next_packet_pubkey_opt.is_some());
  57         let outgoing_packet = msgs::OnionPacket {
  58                 version: 0,
  59                 public_key: next_packet_pubkey_opt.unwrap_or(Err(secp256k1::Error::InvalidPublicKey)),
  60                 hop_data: new_packet_bytes,
  61                 hmac: hop_hmac,
  62         };
  63
  64         let (
  65                 short_channel_id, amt_to_forward, outgoing_cltv_value, inbound_blinding_point
  66         ) = match hop_data {
  67                 msgs::InboundOnionPayload::Forward { short_channel_id, amt_to_forward, outgoing_cltv_value } =>
  68                         (short_channel_id, amt_to_forward, outgoing_cltv_value, None),
  69                 msgs::InboundOnionPayload::BlindedForward {
  70                         short_channel_id, payment_relay, payment_constraints, intro_node_blinding_point, features,
  71                 } => {
  72                         let (amt_to_forward, outgoing_cltv_value) = check_blinded_forward(
  73                                 msg.amount_msat, msg.cltv_expiry, &payment_relay, &payment_constraints, &features
  74                         ).map_err(|()| {
  75                                 // We should be returning malformed here if `msg.blinding_point` is set, but this is
  76                                 // unreachable right now since we checked it in `decode_update_add_htlc_onion`.
  77                                 InboundOnionErr {
  78                                         msg: "Underflow calculating outbound amount or cltv value for blinded forward",
  79                                         err_code: INVALID_ONION_BLINDING,
  80                                         err_data: vec![0; 32],
  81                                 }
  82                         })?;
  83                         (short_channel_id, amt_to_forward, outgoing_cltv_value, Some(intro_node_blinding_point))
  84                 },
  85                 msgs::InboundOnionPayload::Receive { .. } | msgs::InboundOnionPayload::BlindedReceive { .. } =>
  86                         return Err(InboundOnionErr {
  87                                 msg: "Final Node OnionHopData provided for us as an intermediary node",
  88                                 err_code: 0x4000 | 22,
  89                                 err_data: Vec::new(),
  90                         }),
  91         };
  92
  93         Ok(PendingHTLCInfo {
  94                 routing: PendingHTLCRouting::Forward {
  95                         onion_packet: outgoing_packet,
  96                         short_channel_id,
  97                         blinded: inbound_blinding_point.map(|bp| BlindedForward { inbound_blinding_point: bp }),
  98                 },
  99                 payment_hash: msg.payment_hash,
 100                 incoming_shared_secret: shared_secret,
 101                 incoming_amt_msat: Some(msg.amount_msat),
 102                 outgoing_amt_msat: amt_to_forward,
 103                 outgoing_cltv_value,
 104                 skimmed_fee_msat: None,
 105         })
 106 }
 107
 108 pub(super) fn create_recv_pending_htlc_info(
 109         hop_data: msgs::InboundOnionPayload, shared_secret: [u8; 32], payment_hash: PaymentHash,
 110         amt_msat: u64, cltv_expiry: u32, phantom_shared_secret: Option<[u8; 32]>, allow_underpay: bool,
 111         counterparty_skimmed_fee_msat: Option<u64>, current_height: u32, accept_mpp_keysend: bool,
 112 ) -> Result<PendingHTLCInfo, InboundOnionErr> {
 113         let (payment_data, keysend_preimage, custom_tlvs, onion_amt_msat, outgoing_cltv_value, payment_metadata) = match hop_data {
 114                 msgs::InboundOnionPayload::Receive {
 115                         payment_data, keysend_preimage, custom_tlvs, amt_msat, outgoing_cltv_value, payment_metadata, ..
 116                 } =>
 117                         (payment_data, keysend_preimage, custom_tlvs, amt_msat, outgoing_cltv_value, payment_metadata),
 118                 msgs::InboundOnionPayload::BlindedReceive {
 119                         amt_msat, total_msat, outgoing_cltv_value, payment_secret, ..
 120                 } => {
 121                         let payment_data = msgs::FinalOnionHopData { payment_secret, total_msat };
 122                         (Some(payment_data), None, Vec::new(), amt_msat, outgoing_cltv_value, None)
 123                 }
 124                 msgs::InboundOnionPayload::Forward { .. } => {
 125                         return Err(InboundOnionErr {
 126                                 err_code: 0x4000|22,
 127                                 err_data: Vec::new(),
 128                                 msg: "Got non final data with an HMAC of 0",
 129                         })
 130                 },
 131                 msgs::InboundOnionPayload::BlindedForward { .. } => {
 132                         return Err(InboundOnionErr {
 133                                 err_code: INVALID_ONION_BLINDING,
 134                                 err_data: vec![0; 32],
 135                                 msg: "Got blinded non final data with an HMAC of 0",
 136                         })
 137                 }
 138         };
 139         // final_incorrect_cltv_expiry
 140         if outgoing_cltv_value > cltv_expiry {
 141                 return Err(InboundOnionErr {
 142                         msg: "Upstream node set CLTV to less than the CLTV set by the sender",
 143                         err_code: 18,
 144                         err_data: cltv_expiry.to_be_bytes().to_vec()
 145                 })
 146         }
 147         // final_expiry_too_soon
 148         // We have to have some headroom to broadcast on chain if we have the preimage, so make sure
 149         // we have at least HTLC_FAIL_BACK_BUFFER blocks to go.
 150         //
 151         // Also, ensure that, in the case of an unknown preimage for the received payment hash, our
 152         // payment logic has enough time to fail the HTLC backward before our onchain logic triggers a
 153         // channel closure (see HTLC_FAIL_BACK_BUFFER rationale).
 154         if cltv_expiry <= current_height + HTLC_FAIL_BACK_BUFFER + 1 {
 155                 let mut err_data = Vec::with_capacity(12);
 156                 err_data.extend_from_slice(&amt_msat.to_be_bytes());
 157                 err_data.extend_from_slice(&current_height.to_be_bytes());
 158                 return Err(InboundOnionErr {
 159                         err_code: 0x4000 | 15, err_data,
 160                         msg: "The final CLTV expiry is too soon to handle",
 161                 });
 162         }
 163         if (!allow_underpay && onion_amt_msat > amt_msat) ||
 164                 (allow_underpay && onion_amt_msat >
 165                  amt_msat.saturating_add(counterparty_skimmed_fee_msat.unwrap_or(0)))
 166         {
 167                 return Err(InboundOnionErr {
 168                         err_code: 19,
 169                         err_data: amt_msat.to_be_bytes().to_vec(),
 170                         msg: "Upstream node sent less than we were supposed to receive in payment",
 171                 });
 172         }
 173
 174         let routing = if let Some(payment_preimage) = keysend_preimage {
 175                 // We need to check that the sender knows the keysend preimage before processing this
 176                 // payment further. Otherwise, an intermediary routing hop forwarding non-keysend-HTLC X
 177                 // could discover the final destination of X, by probing the adjacent nodes on the route
 178                 // with a keysend payment of identical payment hash to X and observing the processing
 179                 // time discrepancies due to a hash collision with X.
 180                 let hashed_preimage = PaymentHash(Sha256::hash(&payment_preimage.0).to_byte_array());
 181                 if hashed_preimage != payment_hash {
 182                         return Err(InboundOnionErr {
 183                                 err_code: 0x4000|22,
 184                                 err_data: Vec::new(),
 185                                 msg: "Payment preimage didn't match payment hash",
 186                         });
 187                 }
 188                 if !accept_mpp_keysend && payment_data.is_some() {
 189                         return Err(InboundOnionErr {
 190                                 err_code: 0x4000|22,
 191                                 err_data: Vec::new(),
 192                                 msg: "We don't support MPP keysend payments",
 193                         });
 194                 }
 195                 PendingHTLCRouting::ReceiveKeysend {
 196                         payment_data,
 197                         payment_preimage,
 198                         payment_metadata,
 199                         incoming_cltv_expiry: outgoing_cltv_value,
 200                         custom_tlvs,
 201                 }
 202         } else if let Some(data) = payment_data {
 203                 PendingHTLCRouting::Receive {
 204                         payment_data: data,
 205                         payment_metadata,
 206                         incoming_cltv_expiry: outgoing_cltv_value,
 207                         phantom_shared_secret,
 208                         custom_tlvs,
 209                 }
 210         } else {
 211                 return Err(InboundOnionErr {
 212                         err_code: 0x4000|0x2000|3,
 213                         err_data: Vec::new(),
 214                         msg: "We require payment_secrets",
 215                 });
 216         };
 217         Ok(PendingHTLCInfo {
 218                 routing,
 219                 payment_hash,
 220                 incoming_shared_secret: shared_secret,
 221                 incoming_amt_msat: Some(amt_msat),
 222                 outgoing_amt_msat: onion_amt_msat,
 223                 outgoing_cltv_value,
 224                 skimmed_fee_msat: counterparty_skimmed_fee_msat,
 225         })
 226 }
 227
 228 /// Peel one layer off an incoming onion, returning [`PendingHTLCInfo`] (either Forward or Receive).
 229 /// This does all the relevant context-free checks that LDK requires for payment relay or
 230 /// acceptance. If the payment is to be received, and the amount matches the expected amount for
 231 /// a given invoice, this indicates the [`msgs::UpdateAddHTLC`], once fully committed in the
 232 /// channel, will generate an [`Event::PaymentClaimable`].
 233 ///
 234 /// [`Event::PaymentClaimable`]: crate::events::Event::PaymentClaimable
 235 pub fn peel_payment_onion<NS: Deref, L: Deref, T: secp256k1::Verification>(
 236         msg: &msgs::UpdateAddHTLC, node_signer: &NS, logger: &L, secp_ctx: &Secp256k1<T>,
 237         cur_height: u32, accept_mpp_keysend: bool,
 238 ) -> Result<PendingHTLCInfo, InboundOnionErr>
 239 where
 240         NS::Target: NodeSigner,
 241         L::Target: Logger,
 242 {
 243         let (hop, shared_secret, next_packet_details_opt) =
 244                 decode_incoming_update_add_htlc_onion(msg, node_signer, logger, secp_ctx
 245         ).map_err(|e| {
 246                 let (err_code, err_data) = match e {
 247                         HTLCFailureMsg::Malformed(m) => (m.failure_code, Vec::new()),
 248                         HTLCFailureMsg::Relay(r) => (0x4000 | 22, r.reason.data),
 249                 };
 250                 let msg = "Failed to decode update add htlc onion";
 251                 InboundOnionErr { msg, err_code, err_data }
 252         })?;
 253         Ok(match hop {
 254                 onion_utils::Hop::Forward { next_hop_data, next_hop_hmac, new_packet_bytes } => {
 255                         let NextPacketDetails {
 256                                 next_packet_pubkey, outgoing_amt_msat: _, outgoing_scid: _, outgoing_cltv_value
 257                         } = match next_packet_details_opt {
 258                                 Some(next_packet_details) => next_packet_details,
 259                                 // Forward should always include the next hop details
 260                                 None => return Err(InboundOnionErr {
 261                                         msg: "Failed to decode update add htlc onion",
 262                                         err_code: 0x4000 | 22,
 263                                         err_data: Vec::new(),
 264                                 }),
 265                         };
 266
 267                         if let Err((err_msg, code)) = check_incoming_htlc_cltv(
 268                                 cur_height, outgoing_cltv_value, msg.cltv_expiry
 269                         ) {
 270                                 return Err(InboundOnionErr {
 271                                         msg: err_msg,
 272                                         err_code: code,
 273                                         err_data: Vec::new(),
 274                                 });
 275                         }
 276                         create_fwd_pending_htlc_info(
 277                                 msg, next_hop_data, next_hop_hmac, new_packet_bytes, shared_secret,
 278                                 Some(next_packet_pubkey)
 279                         )?
 280                 },
 281                 onion_utils::Hop::Receive(received_data) => {
 282                         create_recv_pending_htlc_info(
 283                                 received_data, shared_secret, msg.payment_hash, msg.amount_msat, msg.cltv_expiry,
 284                                 None, false, msg.skimmed_fee_msat, cur_height, accept_mpp_keysend,
 285                         )?
 286                 }
 287         })
 288 }
 289
 290 pub(super) struct NextPacketDetails {
 291         pub(super) next_packet_pubkey: Result<PublicKey, secp256k1::Error>,
 292         pub(super) outgoing_scid: u64,
 293         pub(super) outgoing_amt_msat: u64,
 294         pub(super) outgoing_cltv_value: u32,
 295 }
 296
 297 pub(super) fn decode_incoming_update_add_htlc_onion<NS: Deref, L: Deref, T: secp256k1::Verification>(
 298         msg: &msgs::UpdateAddHTLC, node_signer: &NS, logger: &L, secp_ctx: &Secp256k1<T>,
 299 ) -> Result<(onion_utils::Hop, [u8; 32], Option<NextPacketDetails>), HTLCFailureMsg>
 300 where
 301         NS::Target: NodeSigner,
 302         L::Target: Logger,
 303 {
 304         macro_rules! return_malformed_err {
 305                 ($msg: expr, $err_code: expr) => {
 306                         {
 307                                 log_info!(logger, "Failed to accept/forward incoming HTLC: {}", $msg);
 308                                 return Err(HTLCFailureMsg::Malformed(msgs::UpdateFailMalformedHTLC {
 309                                         channel_id: msg.channel_id,
 310                                         htlc_id: msg.htlc_id,
 311                                         sha256_of_onion: Sha256::hash(&msg.onion_routing_packet.hop_data).to_byte_array(),
 312                                         failure_code: $err_code,
 313                                 }));
 314                         }
 315                 }
 316         }
 317
 318         if let Err(_) = msg.onion_routing_packet.public_key {
 319                 return_malformed_err!("invalid ephemeral pubkey", 0x8000 | 0x4000 | 6);
 320         }
 321
 322         let shared_secret = node_signer.ecdh(
 323                 Recipient::Node, &msg.onion_routing_packet.public_key.unwrap(), None
 324         ).unwrap().secret_bytes();
 325
 326         if msg.onion_routing_packet.version != 0 {
 327                 //TODO: Spec doesn't indicate if we should only hash hop_data here (and in other
 328                 //sha256_of_onion error data packets), or the entire onion_routing_packet. Either way,
 329                 //the hash doesn't really serve any purpose - in the case of hashing all data, the
 330                 //receiving node would have to brute force to figure out which version was put in the
 331                 //packet by the node that send us the message, in the case of hashing the hop_data, the
 332                 //node knows the HMAC matched, so they already know what is there...
 333                 return_malformed_err!("Unknown onion packet version", 0x8000 | 0x4000 | 4);
 334         }
 335         macro_rules! return_err {
 336                 ($msg: expr, $err_code: expr, $data: expr) => {
 337                         {
 338                                 log_info!(logger, "Failed to accept/forward incoming HTLC: {}", $msg);
 339                                 return Err(HTLCFailureMsg::Relay(msgs::UpdateFailHTLC {
 340                                         channel_id: msg.channel_id,
 341                                         htlc_id: msg.htlc_id,
 342                                         reason: HTLCFailReason::reason($err_code, $data.to_vec())
 343                                                 .get_encrypted_failure_packet(&shared_secret, &None),
 344                                 }));
 345                         }
 346                 }
 347         }
 348
 349         let next_hop = match onion_utils::decode_next_payment_hop(
 350                 shared_secret, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
 351                 msg.payment_hash, node_signer
 352         ) {
 353                 Ok(res) => res,
 354                 Err(onion_utils::OnionDecodeErr::Malformed { err_msg, err_code }) => {
 355                         return_malformed_err!(err_msg, err_code);
 356                 },
 357                 Err(onion_utils::OnionDecodeErr::Relay { err_msg, err_code }) => {
 358                         return_err!(err_msg, err_code, &[0; 0]);
 359                 },
 360         };
 361
 362         let next_packet_details = match next_hop {
 363                 onion_utils::Hop::Forward {
 364                         next_hop_data: msgs::InboundOnionPayload::Forward {
 365                                 short_channel_id, amt_to_forward, outgoing_cltv_value
 366                         }, ..
 367                 } => {
 368                         let next_packet_pubkey = onion_utils::next_hop_pubkey(secp_ctx,
 369                                 msg.onion_routing_packet.public_key.unwrap(), &shared_secret);
 370                         NextPacketDetails {
 371                                 next_packet_pubkey, outgoing_scid: short_channel_id,
 372                                 outgoing_amt_msat: amt_to_forward, outgoing_cltv_value
 373                         }
 374                 },
 375                 onion_utils::Hop::Forward {
 376                         next_hop_data: msgs::InboundOnionPayload::BlindedForward {
 377                                 short_channel_id, ref payment_relay, ref payment_constraints, ref features, ..
 378                         }, ..
 379                 } => {
 380                         let (amt_to_forward, outgoing_cltv_value) = match check_blinded_forward(
 381                                 msg.amount_msat, msg.cltv_expiry, &payment_relay, &payment_constraints, &features
 382                         ) {
 383                                 Ok((amt, cltv)) => (amt, cltv),
 384                                 Err(()) => {
 385                                         return_err!("Underflow calculating outbound amount or cltv value for blinded forward",
 386                                                 INVALID_ONION_BLINDING, &[0; 32]);
 387                                 }
 388                         };
 389                         let next_packet_pubkey = onion_utils::next_hop_pubkey(&secp_ctx,
 390                                 msg.onion_routing_packet.public_key.unwrap(), &shared_secret);
 391                         NextPacketDetails {
 392                                 next_packet_pubkey, outgoing_scid: short_channel_id, outgoing_amt_msat: amt_to_forward,
 393                                 outgoing_cltv_value
 394                         }
 395                 },
 396                 onion_utils::Hop::Receive { .. } => return Ok((next_hop, shared_secret, None)),
 397                 onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::Receive { .. }, .. } |
 398                         onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::BlindedReceive { .. }, .. } =>
 399                 {
 400                         return_err!("Final Node OnionHopData provided for us as an intermediary node", 0x4000 | 22, &[0; 0]);
 401                 }
 402         };
 403
 404         Ok((next_hop, shared_secret, Some(next_packet_details)))
 405 }
 406
 407 pub(super) fn check_incoming_htlc_cltv(
 408         cur_height: u32, outgoing_cltv_value: u32, cltv_expiry: u32
 409 ) -> Result<(), (&'static str, u16)> {
 410         if (cltv_expiry as u64) < (outgoing_cltv_value) as u64 + MIN_CLTV_EXPIRY_DELTA as u64 {
 411                 return Err((
 412                         "Forwarding node has tampered with the intended HTLC values or origin node has an obsolete cltv_expiry_delta",
 413                         0x1000 | 13, // incorrect_cltv_expiry
 414                 ));
 415         }
 416         // Theoretically, channel counterparty shouldn't send us a HTLC expiring now,
 417         // but we want to be robust wrt to counterparty packet sanitization (see
 418         // HTLC_FAIL_BACK_BUFFER rationale).
 419         if cltv_expiry <= cur_height + HTLC_FAIL_BACK_BUFFER as u32 { // expiry_too_soon
 420                 return Err(("CLTV expiry is too close", 0x1000 | 14));
 421         }
 422         if cltv_expiry > cur_height + CLTV_FAR_FAR_AWAY as u32 { // expiry_too_far
 423                 return Err(("CLTV expiry is too far in the future", 21));
 424         }
 425         // If the HTLC expires ~now, don't bother trying to forward it to our
 426         // counterparty. They should fail it anyway, but we don't want to bother with
 427         // the round-trips or risk them deciding they definitely want the HTLC and
 428         // force-closing to ensure they get it if we're offline.
 429         // We previously had a much more aggressive check here which tried to ensure
 430         // our counterparty receives an HTLC which has *our* risk threshold met on it,
 431         // but there is no need to do that, and since we're a bit conservative with our
 432         // risk threshold it just results in failing to forward payments.
 433         if (outgoing_cltv_value) as u64 <= (cur_height + LATENCY_GRACE_PERIOD_BLOCKS) as u64 {
 434                 return Err(("Outgoing CLTV value is too soon", 0x1000 | 14));
 435         }
 436
 437         Ok(())
 438 }
 439
 440 #[cfg(test)]
 441 mod tests {
 442         use bitcoin::hashes::Hash;
 443         use bitcoin::hashes::sha256::Hash as Sha256;
 444         use bitcoin::secp256k1::{PublicKey, SecretKey};
 445         use crate::ln::{PaymentPreimage, PaymentHash, PaymentSecret};
 446         use crate::ln::ChannelId;
 447         use crate::ln::channelmanager::RecipientOnionFields;
 448         use crate::ln::features::{ChannelFeatures, NodeFeatures};
 449         use crate::ln::msgs;
 450         use crate::ln::onion_utils::create_payment_onion;
 451         use crate::routing::router::{Path, RouteHop};
 452         use crate::util::test_utils;
 453
 454         #[test]
 455         fn test_peel_payment_onion() {
 456                 use super::*;
 457                 let secp_ctx = Secp256k1::new();
 458
 459                 let bob = crate::sign::KeysManager::new(&[2; 32], 42, 42);
 460                 let bob_pk = PublicKey::from_secret_key(&secp_ctx, &bob.get_node_secret_key());
 461                 let charlie = crate::sign::KeysManager::new(&[3; 32], 42, 42);
 462                 let charlie_pk = PublicKey::from_secret_key(&secp_ctx, &charlie.get_node_secret_key());
 463
 464                 let (session_priv, total_amt_msat, cur_height, recipient_onion, preimage, payment_hash,
 465                         prng_seed, hops, recipient_amount, pay_secret) = payment_onion_args(bob_pk, charlie_pk);
 466
 467                 let path = Path {
 468                         hops: hops,
 469                         blinded_tail: None,
 470                 };
 471
 472                 let (onion, amount_msat, cltv_expiry) = create_payment_onion(
 473                         &secp_ctx, &path, &session_priv, total_amt_msat, recipient_onion, cur_height,
 474                         &payment_hash, &Some(preimage), prng_seed
 475                 ).unwrap();
 476
 477                 let msg = make_update_add_msg(amount_msat, cltv_expiry, payment_hash, onion);
 478                 let logger = test_utils::TestLogger::with_id("bob".to_string());
 479
 480                 let peeled = peel_payment_onion(&msg, &&bob, &&logger, &secp_ctx, cur_height, true)
 481                         .map_err(|e| e.msg).unwrap();
 482
 483                 let next_onion = match peeled.routing {
 484                         PendingHTLCRouting::Forward { onion_packet, .. } => {
 485                                 onion_packet
 486                         },
 487                         _ => panic!("expected a forwarded onion"),
 488                 };
 489
 490                 let msg2 = make_update_add_msg(amount_msat, cltv_expiry, payment_hash, next_onion);
 491                 let peeled2 = peel_payment_onion(&msg2, &&charlie, &&logger, &secp_ctx, cur_height, true)
 492                         .map_err(|e| e.msg).unwrap();
 493
 494                 match peeled2.routing {
 495                         PendingHTLCRouting::ReceiveKeysend { payment_preimage, payment_data, incoming_cltv_expiry, .. } => {
 496                                 assert_eq!(payment_preimage, preimage);
 497                                 assert_eq!(peeled2.outgoing_amt_msat, recipient_amount);
 498                                 assert_eq!(incoming_cltv_expiry, peeled2.outgoing_cltv_value);
 499                                 let msgs::FinalOnionHopData{total_msat, payment_secret} = payment_data.unwrap();
 500                                 assert_eq!(total_msat, total_amt_msat);
 501                                 assert_eq!(payment_secret, pay_secret);
 502                         },
 503                         _ => panic!("expected a received keysend"),
 504                 };
 505         }
 506
 507         fn make_update_add_msg(
 508                 amount_msat: u64, cltv_expiry: u32, payment_hash: PaymentHash,
 509                 onion_routing_packet: msgs::OnionPacket
 510         ) -> msgs::UpdateAddHTLC {
 511                 msgs::UpdateAddHTLC {
 512                         channel_id: ChannelId::from_bytes([0; 32]),
 513                         htlc_id: 0,
 514                         amount_msat,
 515                         cltv_expiry,
 516                         payment_hash,
 517                         onion_routing_packet,
 518                         skimmed_fee_msat: None,
 519                         blinding_point: None,
 520                 }
 521         }
 522
 523         fn payment_onion_args(hop_pk: PublicKey, recipient_pk: PublicKey) -> (
 524                 SecretKey, u64, u32, RecipientOnionFields, PaymentPreimage, PaymentHash, [u8; 32],
 525                 Vec<RouteHop>, u64, PaymentSecret,
 526         ) {
 527                 let session_priv_bytes = [42; 32];
 528                 let session_priv = SecretKey::from_slice(&session_priv_bytes).unwrap();
 529                 let total_amt_msat = 1000;
 530                 let cur_height = 1000;
 531                 let pay_secret = PaymentSecret([99; 32]);
 532                 let recipient_onion = RecipientOnionFields::secret_only(pay_secret);
 533                 let preimage_bytes = [43; 32];
 534                 let preimage = PaymentPreimage(preimage_bytes);
 535                 let rhash_bytes = Sha256::hash(&preimage_bytes).to_byte_array();
 536                 let payment_hash = PaymentHash(rhash_bytes);
 537                 let prng_seed = [44; 32];
 538
 539                 // make a route alice -> bob -> charlie
 540                 let hop_fee = 1;
 541                 let recipient_amount = total_amt_msat - hop_fee;
 542                 let hops = vec![
 543                         RouteHop {
 544                                 pubkey: hop_pk,
 545                                 fee_msat: hop_fee,
 546                                 cltv_expiry_delta: 42,
 547                                 short_channel_id: 1,
 548                                 node_features: NodeFeatures::empty(),
 549                                 channel_features: ChannelFeatures::empty(),
 550                                 maybe_announced_channel: false,
 551                         },
 552                         RouteHop {
 553                                 pubkey: recipient_pk,
 554                                 fee_msat: recipient_amount,
 555                                 cltv_expiry_delta: 42,
 556                                 short_channel_id: 2,
 557                                 node_features: NodeFeatures::empty(),
 558                                 channel_features: ChannelFeatures::empty(),
 559                                 maybe_announced_channel: false,
 560                         }
 561                 ];
 562
 563                 (session_priv, total_amt_msat, cur_height, recipient_onion, preimage, payment_hash,
 564                         prng_seed, hops, recipient_amount, pay_secret)
 565         }
 566
 567 }