git.bitcoin.ninja Git - rust-lightning/blob - lightning/src/ln/onion_payment.rs

   1 //! Utilities to decode payment onions and do contextless validation of incoming payments.
   2 //!
   3 //! Primarily features [`peel_payment_onion`], which allows the decoding of an onion statelessly
   4 //! and can be used to predict whether we'd accept a payment.
   5
   6 use bitcoin::hashes::{Hash, HashEngine};
   7 use bitcoin::hashes::hmac::{Hmac, HmacEngine};
   8 use bitcoin::hashes::sha256::Hash as Sha256;
   9 use bitcoin::secp256k1::{self, PublicKey, Scalar, Secp256k1};
  10
  11 use crate::blinded_path;
  12 use crate::blinded_path::payment::{PaymentConstraints, PaymentRelay};
  13 use crate::chain::channelmonitor::{HTLC_FAIL_BACK_BUFFER, LATENCY_GRACE_PERIOD_BLOCKS};
  14 use crate::ln::PaymentHash;
  15 use crate::ln::channelmanager::{BlindedForward, CLTV_FAR_FAR_AWAY, HTLCFailureMsg, MIN_CLTV_EXPIRY_DELTA, PendingHTLCInfo, PendingHTLCRouting};
  16 use crate::ln::features::BlindedHopFeatures;
  17 use crate::ln::msgs;
  18 use crate::ln::onion_utils;
  19 use crate::ln::onion_utils::{HTLCFailReason, INVALID_ONION_BLINDING};
  20 use crate::sign::{NodeSigner, Recipient};
  21 use crate::util::logger::Logger;
  22
  23 use crate::prelude::*;
  24 use core::ops::Deref;
  25
  26 /// Invalid inbound onion payment.
  27 pub struct InboundOnionErr {
  28         /// BOLT 4 error code.
  29         pub err_code: u16,
  30         /// Data attached to this error.
  31         pub err_data: Vec<u8>,
  32         /// Error message text.
  33         pub msg: &'static str,
  34 }
  35
  36 fn check_blinded_forward(
  37         inbound_amt_msat: u64, inbound_cltv_expiry: u32, payment_relay: &PaymentRelay,
  38         payment_constraints: &PaymentConstraints, features: &BlindedHopFeatures
  39 ) -> Result<(u64, u32), ()> {
  40         let amt_to_forward = blinded_path::payment::amt_to_forward_msat(
  41                 inbound_amt_msat, payment_relay
  42         ).ok_or(())?;
  43         let outgoing_cltv_value = inbound_cltv_expiry.checked_sub(
  44                 payment_relay.cltv_expiry_delta as u32
  45         ).ok_or(())?;
  46         if inbound_amt_msat < payment_constraints.htlc_minimum_msat ||
  47                 outgoing_cltv_value > payment_constraints.max_cltv_expiry
  48                 { return Err(()) }
  49         if features.requires_unknown_bits_from(&BlindedHopFeatures::empty()) { return Err(()) }
  50         Ok((amt_to_forward, outgoing_cltv_value))
  51 }
  52
  53 pub(super) fn create_fwd_pending_htlc_info(
  54         msg: &msgs::UpdateAddHTLC, hop_data: msgs::InboundOnionPayload, hop_hmac: [u8; 32],
  55         new_packet_bytes: [u8; onion_utils::ONION_DATA_LEN], shared_secret: [u8; 32],
  56         next_packet_pubkey_opt: Option<Result<PublicKey, secp256k1::Error>>
  57 ) -> Result<PendingHTLCInfo, InboundOnionErr> {
  58         debug_assert!(next_packet_pubkey_opt.is_some());
  59         let outgoing_packet = msgs::OnionPacket {
  60                 version: 0,
  61                 public_key: next_packet_pubkey_opt.unwrap_or(Err(secp256k1::Error::InvalidPublicKey)),
  62                 hop_data: new_packet_bytes,
  63                 hmac: hop_hmac,
  64         };
  65
  66         let (
  67                 short_channel_id, amt_to_forward, outgoing_cltv_value, inbound_blinding_point
  68         ) = match hop_data {
  69                 msgs::InboundOnionPayload::Forward { short_channel_id, amt_to_forward, outgoing_cltv_value } =>
  70                         (short_channel_id, amt_to_forward, outgoing_cltv_value, None),
  71                 msgs::InboundOnionPayload::BlindedForward {
  72                         short_channel_id, payment_relay, payment_constraints, intro_node_blinding_point, features,
  73                 } => {
  74                         let (amt_to_forward, outgoing_cltv_value) = check_blinded_forward(
  75                                 msg.amount_msat, msg.cltv_expiry, &payment_relay, &payment_constraints, &features
  76                         ).map_err(|()| {
  77                                 // We should be returning malformed here if `msg.blinding_point` is set, but this is
  78                                 // unreachable right now since we checked it in `decode_update_add_htlc_onion`.
  79                                 InboundOnionErr {
  80                                         msg: "Underflow calculating outbound amount or cltv value for blinded forward",
  81                                         err_code: INVALID_ONION_BLINDING,
  82                                         err_data: vec![0; 32],
  83                                 }
  84                         })?;
  85                         (short_channel_id, amt_to_forward, outgoing_cltv_value, Some(intro_node_blinding_point))
  86                 },
  87                 msgs::InboundOnionPayload::Receive { .. } | msgs::InboundOnionPayload::BlindedReceive { .. } =>
  88                         return Err(InboundOnionErr {
  89                                 msg: "Final Node OnionHopData provided for us as an intermediary node",
  90                                 err_code: 0x4000 | 22,
  91                                 err_data: Vec::new(),
  92                         }),
  93         };
  94
  95         Ok(PendingHTLCInfo {
  96                 routing: PendingHTLCRouting::Forward {
  97                         onion_packet: outgoing_packet,
  98                         short_channel_id,
  99                         blinded: inbound_blinding_point.map(|bp| BlindedForward { inbound_blinding_point: bp }),
 100                 },
 101                 payment_hash: msg.payment_hash,
 102                 incoming_shared_secret: shared_secret,
 103                 incoming_amt_msat: Some(msg.amount_msat),
 104                 outgoing_amt_msat: amt_to_forward,
 105                 outgoing_cltv_value,
 106                 skimmed_fee_msat: None,
 107         })
 108 }
 109
 110 pub(super) fn create_recv_pending_htlc_info(
 111         hop_data: msgs::InboundOnionPayload, shared_secret: [u8; 32], payment_hash: PaymentHash,
 112         amt_msat: u64, cltv_expiry: u32, phantom_shared_secret: Option<[u8; 32]>, allow_underpay: bool,
 113         counterparty_skimmed_fee_msat: Option<u64>, current_height: u32, accept_mpp_keysend: bool,
 114 ) -> Result<PendingHTLCInfo, InboundOnionErr> {
 115         let (
 116                 payment_data, keysend_preimage, custom_tlvs, onion_amt_msat, outgoing_cltv_value,
 117                 payment_metadata, requires_blinded_error
 118         ) = match hop_data {
 119                 msgs::InboundOnionPayload::Receive {
 120                         payment_data, keysend_preimage, custom_tlvs, amt_msat, outgoing_cltv_value, payment_metadata, ..
 121                 } =>
 122                         (payment_data, keysend_preimage, custom_tlvs, amt_msat, outgoing_cltv_value, payment_metadata,
 123                          false),
 124                 msgs::InboundOnionPayload::BlindedReceive {
 125                         amt_msat, total_msat, outgoing_cltv_value, payment_secret, intro_node_blinding_point, ..
 126                 } => {
 127                         let payment_data = msgs::FinalOnionHopData { payment_secret, total_msat };
 128                         (Some(payment_data), None, Vec::new(), amt_msat, outgoing_cltv_value, None,
 129                          intro_node_blinding_point.is_none())
 130                 }
 131                 msgs::InboundOnionPayload::Forward { .. } => {
 132                         return Err(InboundOnionErr {
 133                                 err_code: 0x4000|22,
 134                                 err_data: Vec::new(),
 135                                 msg: "Got non final data with an HMAC of 0",
 136                         })
 137                 },
 138                 msgs::InboundOnionPayload::BlindedForward { .. } => {
 139                         return Err(InboundOnionErr {
 140                                 err_code: INVALID_ONION_BLINDING,
 141                                 err_data: vec![0; 32],
 142                                 msg: "Got blinded non final data with an HMAC of 0",
 143                         })
 144                 }
 145         };
 146         // final_incorrect_cltv_expiry
 147         if outgoing_cltv_value > cltv_expiry {
 148                 return Err(InboundOnionErr {
 149                         msg: "Upstream node set CLTV to less than the CLTV set by the sender",
 150                         err_code: 18,
 151                         err_data: cltv_expiry.to_be_bytes().to_vec()
 152                 })
 153         }
 154         // final_expiry_too_soon
 155         // We have to have some headroom to broadcast on chain if we have the preimage, so make sure
 156         // we have at least HTLC_FAIL_BACK_BUFFER blocks to go.
 157         //
 158         // Also, ensure that, in the case of an unknown preimage for the received payment hash, our
 159         // payment logic has enough time to fail the HTLC backward before our onchain logic triggers a
 160         // channel closure (see HTLC_FAIL_BACK_BUFFER rationale).
 161         if cltv_expiry <= current_height + HTLC_FAIL_BACK_BUFFER + 1 {
 162                 let mut err_data = Vec::with_capacity(12);
 163                 err_data.extend_from_slice(&amt_msat.to_be_bytes());
 164                 err_data.extend_from_slice(&current_height.to_be_bytes());
 165                 return Err(InboundOnionErr {
 166                         err_code: 0x4000 | 15, err_data,
 167                         msg: "The final CLTV expiry is too soon to handle",
 168                 });
 169         }
 170         if (!allow_underpay && onion_amt_msat > amt_msat) ||
 171                 (allow_underpay && onion_amt_msat >
 172                  amt_msat.saturating_add(counterparty_skimmed_fee_msat.unwrap_or(0)))
 173         {
 174                 return Err(InboundOnionErr {
 175                         err_code: 19,
 176                         err_data: amt_msat.to_be_bytes().to_vec(),
 177                         msg: "Upstream node sent less than we were supposed to receive in payment",
 178                 });
 179         }
 180
 181         let routing = if let Some(payment_preimage) = keysend_preimage {
 182                 // We need to check that the sender knows the keysend preimage before processing this
 183                 // payment further. Otherwise, an intermediary routing hop forwarding non-keysend-HTLC X
 184                 // could discover the final destination of X, by probing the adjacent nodes on the route
 185                 // with a keysend payment of identical payment hash to X and observing the processing
 186                 // time discrepancies due to a hash collision with X.
 187                 let hashed_preimage = PaymentHash(Sha256::hash(&payment_preimage.0).to_byte_array());
 188                 if hashed_preimage != payment_hash {
 189                         return Err(InboundOnionErr {
 190                                 err_code: 0x4000|22,
 191                                 err_data: Vec::new(),
 192                                 msg: "Payment preimage didn't match payment hash",
 193                         });
 194                 }
 195                 if !accept_mpp_keysend && payment_data.is_some() {
 196                         return Err(InboundOnionErr {
 197                                 err_code: 0x4000|22,
 198                                 err_data: Vec::new(),
 199                                 msg: "We don't support MPP keysend payments",
 200                         });
 201                 }
 202                 PendingHTLCRouting::ReceiveKeysend {
 203                         payment_data,
 204                         payment_preimage,
 205                         payment_metadata,
 206                         incoming_cltv_expiry: outgoing_cltv_value,
 207                         custom_tlvs,
 208                 }
 209         } else if let Some(data) = payment_data {
 210                 PendingHTLCRouting::Receive {
 211                         payment_data: data,
 212                         payment_metadata,
 213                         incoming_cltv_expiry: outgoing_cltv_value,
 214                         phantom_shared_secret,
 215                         custom_tlvs,
 216                         requires_blinded_error,
 217                 }
 218         } else {
 219                 return Err(InboundOnionErr {
 220                         err_code: 0x4000|0x2000|3,
 221                         err_data: Vec::new(),
 222                         msg: "We require payment_secrets",
 223                 });
 224         };
 225         Ok(PendingHTLCInfo {
 226                 routing,
 227                 payment_hash,
 228                 incoming_shared_secret: shared_secret,
 229                 incoming_amt_msat: Some(amt_msat),
 230                 outgoing_amt_msat: onion_amt_msat,
 231                 outgoing_cltv_value,
 232                 skimmed_fee_msat: counterparty_skimmed_fee_msat,
 233         })
 234 }
 235
 236 /// Peel one layer off an incoming onion, returning a [`PendingHTLCInfo`] that contains information
 237 /// about the intended next-hop for the HTLC.
 238 ///
 239 /// This does all the relevant context-free checks that LDK requires for payment relay or
 240 /// acceptance. If the payment is to be received, and the amount matches the expected amount for
 241 /// a given invoice, this indicates the [`msgs::UpdateAddHTLC`], once fully committed in the
 242 /// channel, will generate an [`Event::PaymentClaimable`].
 243 ///
 244 /// [`Event::PaymentClaimable`]: crate::events::Event::PaymentClaimable
 245 pub fn peel_payment_onion<NS: Deref, L: Deref, T: secp256k1::Verification>(
 246         msg: &msgs::UpdateAddHTLC, node_signer: &NS, logger: &L, secp_ctx: &Secp256k1<T>,
 247         cur_height: u32, accept_mpp_keysend: bool, allow_skimmed_fees: bool,
 248 ) -> Result<PendingHTLCInfo, InboundOnionErr>
 249 where
 250         NS::Target: NodeSigner,
 251         L::Target: Logger,
 252 {
 253         let (hop, shared_secret, next_packet_details_opt) =
 254                 decode_incoming_update_add_htlc_onion(msg, node_signer, logger, secp_ctx
 255         ).map_err(|e| {
 256                 let (err_code, err_data) = match e {
 257                         HTLCFailureMsg::Malformed(m) => (m.failure_code, Vec::new()),
 258                         HTLCFailureMsg::Relay(r) => (0x4000 | 22, r.reason.data),
 259                 };
 260                 let msg = "Failed to decode update add htlc onion";
 261                 InboundOnionErr { msg, err_code, err_data }
 262         })?;
 263         Ok(match hop {
 264                 onion_utils::Hop::Forward { next_hop_data, next_hop_hmac, new_packet_bytes } => {
 265                         let NextPacketDetails {
 266                                 next_packet_pubkey, outgoing_amt_msat: _, outgoing_scid: _, outgoing_cltv_value
 267                         } = match next_packet_details_opt {
 268                                 Some(next_packet_details) => next_packet_details,
 269                                 // Forward should always include the next hop details
 270                                 None => return Err(InboundOnionErr {
 271                                         msg: "Failed to decode update add htlc onion",
 272                                         err_code: 0x4000 | 22,
 273                                         err_data: Vec::new(),
 274                                 }),
 275                         };
 276
 277                         if let Err((err_msg, code)) = check_incoming_htlc_cltv(
 278                                 cur_height, outgoing_cltv_value, msg.cltv_expiry
 279                         ) {
 280                                 return Err(InboundOnionErr {
 281                                         msg: err_msg,
 282                                         err_code: code,
 283                                         err_data: Vec::new(),
 284                                 });
 285                         }
 286
 287                         // TODO: If this is potentially a phantom payment we should decode the phantom payment
 288                         // onion here and check it.
 289
 290                         create_fwd_pending_htlc_info(
 291                                 msg, next_hop_data, next_hop_hmac, new_packet_bytes, shared_secret,
 292                                 Some(next_packet_pubkey)
 293                         )?
 294                 },
 295                 onion_utils::Hop::Receive(received_data) => {
 296                         create_recv_pending_htlc_info(
 297                                 received_data, shared_secret, msg.payment_hash, msg.amount_msat, msg.cltv_expiry,
 298                                 None, allow_skimmed_fees, msg.skimmed_fee_msat, cur_height, accept_mpp_keysend,
 299                         )?
 300                 }
 301         })
 302 }
 303
 304 pub(super) struct NextPacketDetails {
 305         pub(super) next_packet_pubkey: Result<PublicKey, secp256k1::Error>,
 306         pub(super) outgoing_scid: u64,
 307         pub(super) outgoing_amt_msat: u64,
 308         pub(super) outgoing_cltv_value: u32,
 309 }
 310
 311 pub(super) fn decode_incoming_update_add_htlc_onion<NS: Deref, L: Deref, T: secp256k1::Verification>(
 312         msg: &msgs::UpdateAddHTLC, node_signer: &NS, logger: &L, secp_ctx: &Secp256k1<T>,
 313 ) -> Result<(onion_utils::Hop, [u8; 32], Option<NextPacketDetails>), HTLCFailureMsg>
 314 where
 315         NS::Target: NodeSigner,
 316         L::Target: Logger,
 317 {
 318         macro_rules! return_malformed_err {
 319                 ($msg: expr, $err_code: expr) => {
 320                         {
 321                                 log_info!(logger, "Failed to accept/forward incoming HTLC: {}", $msg);
 322                                 let (sha256_of_onion, failure_code) = if msg.blinding_point.is_some() {
 323                                         ([0; 32], INVALID_ONION_BLINDING)
 324                                 } else {
 325                                         (Sha256::hash(&msg.onion_routing_packet.hop_data).to_byte_array(), $err_code)
 326                                 };
 327                                 return Err(HTLCFailureMsg::Malformed(msgs::UpdateFailMalformedHTLC {
 328                                         channel_id: msg.channel_id,
 329                                         htlc_id: msg.htlc_id,
 330                                         sha256_of_onion,
 331                                         failure_code,
 332                                 }));
 333                         }
 334                 }
 335         }
 336
 337         if let Err(_) = msg.onion_routing_packet.public_key {
 338                 return_malformed_err!("invalid ephemeral pubkey", 0x8000 | 0x4000 | 6);
 339         }
 340
 341         let blinded_node_id_tweak = msg.blinding_point.map(|bp| {
 342                 let blinded_tlvs_ss = node_signer.ecdh(Recipient::Node, &bp, None).unwrap().secret_bytes();
 343                 let mut hmac = HmacEngine::<Sha256>::new(b"blinded_node_id");
 344                 hmac.input(blinded_tlvs_ss.as_ref());
 345                 Scalar::from_be_bytes(Hmac::from_engine(hmac).to_byte_array()).unwrap()
 346         });
 347         let shared_secret = node_signer.ecdh(
 348                 Recipient::Node, &msg.onion_routing_packet.public_key.unwrap(), blinded_node_id_tweak.as_ref()
 349         ).unwrap().secret_bytes();
 350
 351         if msg.onion_routing_packet.version != 0 {
 352                 //TODO: Spec doesn't indicate if we should only hash hop_data here (and in other
 353                 //sha256_of_onion error data packets), or the entire onion_routing_packet. Either way,
 354                 //the hash doesn't really serve any purpose - in the case of hashing all data, the
 355                 //receiving node would have to brute force to figure out which version was put in the
 356                 //packet by the node that send us the message, in the case of hashing the hop_data, the
 357                 //node knows the HMAC matched, so they already know what is there...
 358                 return_malformed_err!("Unknown onion packet version", 0x8000 | 0x4000 | 4);
 359         }
 360         macro_rules! return_err {
 361                 ($msg: expr, $err_code: expr, $data: expr) => {
 362                         {
 363                                 if msg.blinding_point.is_some() {
 364                                         return_malformed_err!($msg, INVALID_ONION_BLINDING)
 365                                 }
 366
 367                                 log_info!(logger, "Failed to accept/forward incoming HTLC: {}", $msg);
 368                                 return Err(HTLCFailureMsg::Relay(msgs::UpdateFailHTLC {
 369                                         channel_id: msg.channel_id,
 370                                         htlc_id: msg.htlc_id,
 371                                         reason: HTLCFailReason::reason($err_code, $data.to_vec())
 372                                                 .get_encrypted_failure_packet(&shared_secret, &None),
 373                                 }));
 374                         }
 375                 }
 376         }
 377
 378         let next_hop = match onion_utils::decode_next_payment_hop(
 379                 shared_secret, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
 380                 msg.payment_hash, msg.blinding_point, node_signer
 381         ) {
 382                 Ok(res) => res,
 383                 Err(onion_utils::OnionDecodeErr::Malformed { err_msg, err_code }) => {
 384                         return_malformed_err!(err_msg, err_code);
 385                 },
 386                 Err(onion_utils::OnionDecodeErr::Relay { err_msg, err_code }) => {
 387                         return_err!(err_msg, err_code, &[0; 0]);
 388                 },
 389         };
 390
 391         let next_packet_details = match next_hop {
 392                 onion_utils::Hop::Forward {
 393                         next_hop_data: msgs::InboundOnionPayload::Forward {
 394                                 short_channel_id, amt_to_forward, outgoing_cltv_value
 395                         }, ..
 396                 } => {
 397                         let next_packet_pubkey = onion_utils::next_hop_pubkey(secp_ctx,
 398                                 msg.onion_routing_packet.public_key.unwrap(), &shared_secret);
 399                         NextPacketDetails {
 400                                 next_packet_pubkey, outgoing_scid: short_channel_id,
 401                                 outgoing_amt_msat: amt_to_forward, outgoing_cltv_value
 402                         }
 403                 },
 404                 onion_utils::Hop::Forward {
 405                         next_hop_data: msgs::InboundOnionPayload::BlindedForward {
 406                                 short_channel_id, ref payment_relay, ref payment_constraints, ref features, ..
 407                         }, ..
 408                 } => {
 409                         let (amt_to_forward, outgoing_cltv_value) = match check_blinded_forward(
 410                                 msg.amount_msat, msg.cltv_expiry, &payment_relay, &payment_constraints, &features
 411                         ) {
 412                                 Ok((amt, cltv)) => (amt, cltv),
 413                                 Err(()) => {
 414                                         return_err!("Underflow calculating outbound amount or cltv value for blinded forward",
 415                                                 INVALID_ONION_BLINDING, &[0; 32]);
 416                                 }
 417                         };
 418                         let next_packet_pubkey = onion_utils::next_hop_pubkey(&secp_ctx,
 419                                 msg.onion_routing_packet.public_key.unwrap(), &shared_secret);
 420                         NextPacketDetails {
 421                                 next_packet_pubkey, outgoing_scid: short_channel_id, outgoing_amt_msat: amt_to_forward,
 422                                 outgoing_cltv_value
 423                         }
 424                 },
 425                 onion_utils::Hop::Receive { .. } => return Ok((next_hop, shared_secret, None)),
 426                 onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::Receive { .. }, .. } |
 427                         onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::BlindedReceive { .. }, .. } =>
 428                 {
 429                         return_err!("Final Node OnionHopData provided for us as an intermediary node", 0x4000 | 22, &[0; 0]);
 430                 }
 431         };
 432
 433         Ok((next_hop, shared_secret, Some(next_packet_details)))
 434 }
 435
 436 pub(super) fn check_incoming_htlc_cltv(
 437         cur_height: u32, outgoing_cltv_value: u32, cltv_expiry: u32
 438 ) -> Result<(), (&'static str, u16)> {
 439         if (cltv_expiry as u64) < (outgoing_cltv_value) as u64 + MIN_CLTV_EXPIRY_DELTA as u64 {
 440                 return Err((
 441                         "Forwarding node has tampered with the intended HTLC values or origin node has an obsolete cltv_expiry_delta",
 442                         0x1000 | 13, // incorrect_cltv_expiry
 443                 ));
 444         }
 445         // Theoretically, channel counterparty shouldn't send us a HTLC expiring now,
 446         // but we want to be robust wrt to counterparty packet sanitization (see
 447         // HTLC_FAIL_BACK_BUFFER rationale).
 448         if cltv_expiry <= cur_height + HTLC_FAIL_BACK_BUFFER as u32 { // expiry_too_soon
 449                 return Err(("CLTV expiry is too close", 0x1000 | 14));
 450         }
 451         if cltv_expiry > cur_height + CLTV_FAR_FAR_AWAY as u32 { // expiry_too_far
 452                 return Err(("CLTV expiry is too far in the future", 21));
 453         }
 454         // If the HTLC expires ~now, don't bother trying to forward it to our
 455         // counterparty. They should fail it anyway, but we don't want to bother with
 456         // the round-trips or risk them deciding they definitely want the HTLC and
 457         // force-closing to ensure they get it if we're offline.
 458         // We previously had a much more aggressive check here which tried to ensure
 459         // our counterparty receives an HTLC which has *our* risk threshold met on it,
 460         // but there is no need to do that, and since we're a bit conservative with our
 461         // risk threshold it just results in failing to forward payments.
 462         if (outgoing_cltv_value) as u64 <= (cur_height + LATENCY_GRACE_PERIOD_BLOCKS) as u64 {
 463                 return Err(("Outgoing CLTV value is too soon", 0x1000 | 14));
 464         }
 465
 466         Ok(())
 467 }
 468
 469 #[cfg(test)]
 470 mod tests {
 471         use bitcoin::hashes::Hash;
 472         use bitcoin::hashes::sha256::Hash as Sha256;
 473         use bitcoin::secp256k1::{PublicKey, SecretKey};
 474         use crate::ln::{PaymentPreimage, PaymentHash, PaymentSecret};
 475         use crate::ln::ChannelId;
 476         use crate::ln::channelmanager::RecipientOnionFields;
 477         use crate::ln::features::{ChannelFeatures, NodeFeatures};
 478         use crate::ln::msgs;
 479         use crate::ln::onion_utils::create_payment_onion;
 480         use crate::routing::router::{Path, RouteHop};
 481         use crate::util::test_utils;
 482
 483         #[test]
 484         fn test_peel_payment_onion() {
 485                 use super::*;
 486                 let secp_ctx = Secp256k1::new();
 487
 488                 let bob = crate::sign::KeysManager::new(&[2; 32], 42, 42);
 489                 let bob_pk = PublicKey::from_secret_key(&secp_ctx, &bob.get_node_secret_key());
 490                 let charlie = crate::sign::KeysManager::new(&[3; 32], 42, 42);
 491                 let charlie_pk = PublicKey::from_secret_key(&secp_ctx, &charlie.get_node_secret_key());
 492
 493                 let (session_priv, total_amt_msat, cur_height, recipient_onion, preimage, payment_hash,
 494                         prng_seed, hops, recipient_amount, pay_secret) = payment_onion_args(bob_pk, charlie_pk);
 495
 496                 let path = Path {
 497                         hops: hops,
 498                         blinded_tail: None,
 499                 };
 500
 501                 let (onion, amount_msat, cltv_expiry) = create_payment_onion(
 502                         &secp_ctx, &path, &session_priv, total_amt_msat, recipient_onion, cur_height,
 503                         &payment_hash, &Some(preimage), prng_seed
 504                 ).unwrap();
 505
 506                 let msg = make_update_add_msg(amount_msat, cltv_expiry, payment_hash, onion);
 507                 let logger = test_utils::TestLogger::with_id("bob".to_string());
 508
 509                 let peeled = peel_payment_onion(&msg, &&bob, &&logger, &secp_ctx, cur_height, true, false)
 510                         .map_err(|e| e.msg).unwrap();
 511
 512                 let next_onion = match peeled.routing {
 513                         PendingHTLCRouting::Forward { onion_packet, .. } => {
 514                                 onion_packet
 515                         },
 516                         _ => panic!("expected a forwarded onion"),
 517                 };
 518
 519                 let msg2 = make_update_add_msg(amount_msat, cltv_expiry, payment_hash, next_onion);
 520                 let peeled2 = peel_payment_onion(&msg2, &&charlie, &&logger, &secp_ctx, cur_height, true, false)
 521                         .map_err(|e| e.msg).unwrap();
 522
 523                 match peeled2.routing {
 524                         PendingHTLCRouting::ReceiveKeysend { payment_preimage, payment_data, incoming_cltv_expiry, .. } => {
 525                                 assert_eq!(payment_preimage, preimage);
 526                                 assert_eq!(peeled2.outgoing_amt_msat, recipient_amount);
 527                                 assert_eq!(incoming_cltv_expiry, peeled2.outgoing_cltv_value);
 528                                 let msgs::FinalOnionHopData{total_msat, payment_secret} = payment_data.unwrap();
 529                                 assert_eq!(total_msat, total_amt_msat);
 530                                 assert_eq!(payment_secret, pay_secret);
 531                         },
 532                         _ => panic!("expected a received keysend"),
 533                 };
 534         }
 535
 536         fn make_update_add_msg(
 537                 amount_msat: u64, cltv_expiry: u32, payment_hash: PaymentHash,
 538                 onion_routing_packet: msgs::OnionPacket
 539         ) -> msgs::UpdateAddHTLC {
 540                 msgs::UpdateAddHTLC {
 541                         channel_id: ChannelId::from_bytes([0; 32]),
 542                         htlc_id: 0,
 543                         amount_msat,
 544                         cltv_expiry,
 545                         payment_hash,
 546                         onion_routing_packet,
 547                         skimmed_fee_msat: None,
 548                         blinding_point: None,
 549                 }
 550         }
 551
 552         fn payment_onion_args(hop_pk: PublicKey, recipient_pk: PublicKey) -> (
 553                 SecretKey, u64, u32, RecipientOnionFields, PaymentPreimage, PaymentHash, [u8; 32],
 554                 Vec<RouteHop>, u64, PaymentSecret,
 555         ) {
 556                 let session_priv_bytes = [42; 32];
 557                 let session_priv = SecretKey::from_slice(&session_priv_bytes).unwrap();
 558                 let total_amt_msat = 1000;
 559                 let cur_height = 1000;
 560                 let pay_secret = PaymentSecret([99; 32]);
 561                 let recipient_onion = RecipientOnionFields::secret_only(pay_secret);
 562                 let preimage_bytes = [43; 32];
 563                 let preimage = PaymentPreimage(preimage_bytes);
 564                 let rhash_bytes = Sha256::hash(&preimage_bytes).to_byte_array();
 565                 let payment_hash = PaymentHash(rhash_bytes);
 566                 let prng_seed = [44; 32];
 567
 568                 // make a route alice -> bob -> charlie
 569                 let hop_fee = 1;
 570                 let recipient_amount = total_amt_msat - hop_fee;
 571                 let hops = vec![
 572                         RouteHop {
 573                                 pubkey: hop_pk,
 574                                 fee_msat: hop_fee,
 575                                 cltv_expiry_delta: 42,
 576                                 short_channel_id: 1,
 577                                 node_features: NodeFeatures::empty(),
 578                                 channel_features: ChannelFeatures::empty(),
 579                                 maybe_announced_channel: false,
 580                         },
 581                         RouteHop {
 582                                 pubkey: recipient_pk,
 583                                 fee_msat: recipient_amount,
 584                                 cltv_expiry_delta: 42,
 585                                 short_channel_id: 2,
 586                                 node_features: NodeFeatures::empty(),
 587                                 channel_features: ChannelFeatures::empty(),
 588                                 maybe_announced_channel: false,
 589                         }
 590                 ];
 591
 592                 (session_priv, total_amt_msat, cur_height, recipient_onion, preimage, payment_hash,
 593                         prng_seed, hops, recipient_amount, pay_secret)
 594         }
 595
 596 }