1 //! Utilities to decode payment onions and do contextless validation of incoming payments.
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.
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};
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;
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;
23 use crate::prelude::*;
26 /// Invalid inbound onion payment.
27 pub struct InboundOnionErr {
28 /// BOLT 4 error code.
30 /// Data attached to this error.
31 pub err_data: Vec<u8>,
32 /// Error message text.
33 pub msg: &'static str,
36 fn check_blinded_payment_constraints(
37 amt_msat: u64, cltv_expiry: u32, constraints: &PaymentConstraints
39 if amt_msat < constraints.htlc_minimum_msat ||
40 cltv_expiry > constraints.max_cltv_expiry
45 fn check_blinded_forward(
46 inbound_amt_msat: u64, inbound_cltv_expiry: u32, payment_relay: &PaymentRelay,
47 payment_constraints: &PaymentConstraints, features: &BlindedHopFeatures
48 ) -> Result<(u64, u32), ()> {
49 let amt_to_forward = blinded_path::payment::amt_to_forward_msat(
50 inbound_amt_msat, payment_relay
52 let outgoing_cltv_value = inbound_cltv_expiry.checked_sub(
53 payment_relay.cltv_expiry_delta as u32
55 check_blinded_payment_constraints(inbound_amt_msat, outgoing_cltv_value, payment_constraints)?;
57 if features.requires_unknown_bits_from(&BlindedHopFeatures::empty()) { return Err(()) }
58 Ok((amt_to_forward, outgoing_cltv_value))
61 pub(super) fn create_fwd_pending_htlc_info(
62 msg: &msgs::UpdateAddHTLC, hop_data: msgs::InboundOnionPayload, hop_hmac: [u8; 32],
63 new_packet_bytes: [u8; onion_utils::ONION_DATA_LEN], shared_secret: [u8; 32],
64 next_packet_pubkey_opt: Option<Result<PublicKey, secp256k1::Error>>
65 ) -> Result<PendingHTLCInfo, InboundOnionErr> {
66 debug_assert!(next_packet_pubkey_opt.is_some());
67 let outgoing_packet = msgs::OnionPacket {
69 public_key: next_packet_pubkey_opt.unwrap_or(Err(secp256k1::Error::InvalidPublicKey)),
70 hop_data: new_packet_bytes,
75 short_channel_id, amt_to_forward, outgoing_cltv_value, inbound_blinding_point
77 msgs::InboundOnionPayload::Forward { short_channel_id, amt_to_forward, outgoing_cltv_value } =>
78 (short_channel_id, amt_to_forward, outgoing_cltv_value, None),
79 msgs::InboundOnionPayload::BlindedForward {
80 short_channel_id, payment_relay, payment_constraints, intro_node_blinding_point, features,
82 let (amt_to_forward, outgoing_cltv_value) = check_blinded_forward(
83 msg.amount_msat, msg.cltv_expiry, &payment_relay, &payment_constraints, &features
85 // We should be returning malformed here if `msg.blinding_point` is set, but this is
86 // unreachable right now since we checked it in `decode_update_add_htlc_onion`.
88 msg: "Underflow calculating outbound amount or cltv value for blinded forward",
89 err_code: INVALID_ONION_BLINDING,
90 err_data: vec![0; 32],
93 (short_channel_id, amt_to_forward, outgoing_cltv_value, Some(intro_node_blinding_point))
95 msgs::InboundOnionPayload::Receive { .. } | msgs::InboundOnionPayload::BlindedReceive { .. } =>
96 return Err(InboundOnionErr {
97 msg: "Final Node OnionHopData provided for us as an intermediary node",
98 err_code: 0x4000 | 22,
104 routing: PendingHTLCRouting::Forward {
105 onion_packet: outgoing_packet,
107 blinded: inbound_blinding_point.map(|bp| BlindedForward { inbound_blinding_point: bp }),
109 payment_hash: msg.payment_hash,
110 incoming_shared_secret: shared_secret,
111 incoming_amt_msat: Some(msg.amount_msat),
112 outgoing_amt_msat: amt_to_forward,
114 skimmed_fee_msat: None,
118 pub(super) fn create_recv_pending_htlc_info(
119 hop_data: msgs::InboundOnionPayload, shared_secret: [u8; 32], payment_hash: PaymentHash,
120 amt_msat: u64, cltv_expiry: u32, phantom_shared_secret: Option<[u8; 32]>, allow_underpay: bool,
121 counterparty_skimmed_fee_msat: Option<u64>, current_height: u32, accept_mpp_keysend: bool,
122 ) -> Result<PendingHTLCInfo, InboundOnionErr> {
124 payment_data, keysend_preimage, custom_tlvs, onion_amt_msat, outgoing_cltv_value,
125 payment_metadata, requires_blinded_error
127 msgs::InboundOnionPayload::Receive {
128 payment_data, keysend_preimage, custom_tlvs, amt_msat, outgoing_cltv_value, payment_metadata, ..
130 (payment_data, keysend_preimage, custom_tlvs, amt_msat, outgoing_cltv_value, payment_metadata,
132 msgs::InboundOnionPayload::BlindedReceive {
133 amt_msat, total_msat, outgoing_cltv_value, payment_secret, intro_node_blinding_point,
134 payment_constraints, ..
136 check_blinded_payment_constraints(amt_msat, cltv_expiry, &payment_constraints)
139 err_code: INVALID_ONION_BLINDING,
140 err_data: vec![0; 32],
141 msg: "Amount or cltv_expiry violated blinded payment constraints",
144 let payment_data = msgs::FinalOnionHopData { payment_secret, total_msat };
145 (Some(payment_data), None, Vec::new(), amt_msat, outgoing_cltv_value, None,
146 intro_node_blinding_point.is_none())
148 msgs::InboundOnionPayload::Forward { .. } => {
149 return Err(InboundOnionErr {
151 err_data: Vec::new(),
152 msg: "Got non final data with an HMAC of 0",
155 msgs::InboundOnionPayload::BlindedForward { .. } => {
156 return Err(InboundOnionErr {
157 err_code: INVALID_ONION_BLINDING,
158 err_data: vec![0; 32],
159 msg: "Got blinded non final data with an HMAC of 0",
163 // final_incorrect_cltv_expiry
164 if outgoing_cltv_value > cltv_expiry {
165 return Err(InboundOnionErr {
166 msg: "Upstream node set CLTV to less than the CLTV set by the sender",
168 err_data: cltv_expiry.to_be_bytes().to_vec()
171 // final_expiry_too_soon
172 // We have to have some headroom to broadcast on chain if we have the preimage, so make sure
173 // we have at least HTLC_FAIL_BACK_BUFFER blocks to go.
175 // Also, ensure that, in the case of an unknown preimage for the received payment hash, our
176 // payment logic has enough time to fail the HTLC backward before our onchain logic triggers a
177 // channel closure (see HTLC_FAIL_BACK_BUFFER rationale).
178 if cltv_expiry <= current_height + HTLC_FAIL_BACK_BUFFER + 1 {
179 let mut err_data = Vec::with_capacity(12);
180 err_data.extend_from_slice(&amt_msat.to_be_bytes());
181 err_data.extend_from_slice(¤t_height.to_be_bytes());
182 return Err(InboundOnionErr {
183 err_code: 0x4000 | 15, err_data,
184 msg: "The final CLTV expiry is too soon to handle",
187 if (!allow_underpay && onion_amt_msat > amt_msat) ||
188 (allow_underpay && onion_amt_msat >
189 amt_msat.saturating_add(counterparty_skimmed_fee_msat.unwrap_or(0)))
191 return Err(InboundOnionErr {
193 err_data: amt_msat.to_be_bytes().to_vec(),
194 msg: "Upstream node sent less than we were supposed to receive in payment",
198 let routing = if let Some(payment_preimage) = keysend_preimage {
199 // We need to check that the sender knows the keysend preimage before processing this
200 // payment further. Otherwise, an intermediary routing hop forwarding non-keysend-HTLC X
201 // could discover the final destination of X, by probing the adjacent nodes on the route
202 // with a keysend payment of identical payment hash to X and observing the processing
203 // time discrepancies due to a hash collision with X.
204 let hashed_preimage = PaymentHash(Sha256::hash(&payment_preimage.0).to_byte_array());
205 if hashed_preimage != payment_hash {
206 return Err(InboundOnionErr {
208 err_data: Vec::new(),
209 msg: "Payment preimage didn't match payment hash",
212 if !accept_mpp_keysend && payment_data.is_some() {
213 return Err(InboundOnionErr {
215 err_data: Vec::new(),
216 msg: "We don't support MPP keysend payments",
219 PendingHTLCRouting::ReceiveKeysend {
223 incoming_cltv_expiry: outgoing_cltv_value,
226 } else if let Some(data) = payment_data {
227 PendingHTLCRouting::Receive {
230 incoming_cltv_expiry: outgoing_cltv_value,
231 phantom_shared_secret,
233 requires_blinded_error,
236 return Err(InboundOnionErr {
237 err_code: 0x4000|0x2000|3,
238 err_data: Vec::new(),
239 msg: "We require payment_secrets",
245 incoming_shared_secret: shared_secret,
246 incoming_amt_msat: Some(amt_msat),
247 outgoing_amt_msat: onion_amt_msat,
249 skimmed_fee_msat: counterparty_skimmed_fee_msat,
253 /// Peel one layer off an incoming onion, returning a [`PendingHTLCInfo`] that contains information
254 /// about the intended next-hop for the HTLC.
256 /// This does all the relevant context-free checks that LDK requires for payment relay or
257 /// acceptance. If the payment is to be received, and the amount matches the expected amount for
258 /// a given invoice, this indicates the [`msgs::UpdateAddHTLC`], once fully committed in the
259 /// channel, will generate an [`Event::PaymentClaimable`].
261 /// [`Event::PaymentClaimable`]: crate::events::Event::PaymentClaimable
262 pub fn peel_payment_onion<NS: Deref, L: Deref, T: secp256k1::Verification>(
263 msg: &msgs::UpdateAddHTLC, node_signer: &NS, logger: &L, secp_ctx: &Secp256k1<T>,
264 cur_height: u32, accept_mpp_keysend: bool, allow_skimmed_fees: bool,
265 ) -> Result<PendingHTLCInfo, InboundOnionErr>
267 NS::Target: NodeSigner,
270 let (hop, shared_secret, next_packet_details_opt) =
271 decode_incoming_update_add_htlc_onion(msg, node_signer, logger, secp_ctx
273 let (err_code, err_data) = match e {
274 HTLCFailureMsg::Malformed(m) => (m.failure_code, Vec::new()),
275 HTLCFailureMsg::Relay(r) => (0x4000 | 22, r.reason.data),
277 let msg = "Failed to decode update add htlc onion";
278 InboundOnionErr { msg, err_code, err_data }
281 onion_utils::Hop::Forward { next_hop_data, next_hop_hmac, new_packet_bytes } => {
282 let NextPacketDetails {
283 next_packet_pubkey, outgoing_amt_msat: _, outgoing_scid: _, outgoing_cltv_value
284 } = match next_packet_details_opt {
285 Some(next_packet_details) => next_packet_details,
286 // Forward should always include the next hop details
287 None => return Err(InboundOnionErr {
288 msg: "Failed to decode update add htlc onion",
289 err_code: 0x4000 | 22,
290 err_data: Vec::new(),
294 if let Err((err_msg, code)) = check_incoming_htlc_cltv(
295 cur_height, outgoing_cltv_value, msg.cltv_expiry
297 return Err(InboundOnionErr {
300 err_data: Vec::new(),
304 // TODO: If this is potentially a phantom payment we should decode the phantom payment
305 // onion here and check it.
307 create_fwd_pending_htlc_info(
308 msg, next_hop_data, next_hop_hmac, new_packet_bytes, shared_secret,
309 Some(next_packet_pubkey)
312 onion_utils::Hop::Receive(received_data) => {
313 create_recv_pending_htlc_info(
314 received_data, shared_secret, msg.payment_hash, msg.amount_msat, msg.cltv_expiry,
315 None, allow_skimmed_fees, msg.skimmed_fee_msat, cur_height, accept_mpp_keysend,
321 pub(super) struct NextPacketDetails {
322 pub(super) next_packet_pubkey: Result<PublicKey, secp256k1::Error>,
323 pub(super) outgoing_scid: u64,
324 pub(super) outgoing_amt_msat: u64,
325 pub(super) outgoing_cltv_value: u32,
328 pub(super) fn decode_incoming_update_add_htlc_onion<NS: Deref, L: Deref, T: secp256k1::Verification>(
329 msg: &msgs::UpdateAddHTLC, node_signer: &NS, logger: &L, secp_ctx: &Secp256k1<T>,
330 ) -> Result<(onion_utils::Hop, [u8; 32], Option<NextPacketDetails>), HTLCFailureMsg>
332 NS::Target: NodeSigner,
335 macro_rules! return_malformed_err {
336 ($msg: expr, $err_code: expr) => {
338 log_info!(logger, "Failed to accept/forward incoming HTLC: {}", $msg);
339 let (sha256_of_onion, failure_code) = if msg.blinding_point.is_some() {
340 ([0; 32], INVALID_ONION_BLINDING)
342 (Sha256::hash(&msg.onion_routing_packet.hop_data).to_byte_array(), $err_code)
344 return Err(HTLCFailureMsg::Malformed(msgs::UpdateFailMalformedHTLC {
345 channel_id: msg.channel_id,
346 htlc_id: msg.htlc_id,
354 if let Err(_) = msg.onion_routing_packet.public_key {
355 return_malformed_err!("invalid ephemeral pubkey", 0x8000 | 0x4000 | 6);
358 let blinded_node_id_tweak = msg.blinding_point.map(|bp| {
359 let blinded_tlvs_ss = node_signer.ecdh(Recipient::Node, &bp, None).unwrap().secret_bytes();
360 let mut hmac = HmacEngine::<Sha256>::new(b"blinded_node_id");
361 hmac.input(blinded_tlvs_ss.as_ref());
362 Scalar::from_be_bytes(Hmac::from_engine(hmac).to_byte_array()).unwrap()
364 let shared_secret = node_signer.ecdh(
365 Recipient::Node, &msg.onion_routing_packet.public_key.unwrap(), blinded_node_id_tweak.as_ref()
366 ).unwrap().secret_bytes();
368 if msg.onion_routing_packet.version != 0 {
369 //TODO: Spec doesn't indicate if we should only hash hop_data here (and in other
370 //sha256_of_onion error data packets), or the entire onion_routing_packet. Either way,
371 //the hash doesn't really serve any purpose - in the case of hashing all data, the
372 //receiving node would have to brute force to figure out which version was put in the
373 //packet by the node that send us the message, in the case of hashing the hop_data, the
374 //node knows the HMAC matched, so they already know what is there...
375 return_malformed_err!("Unknown onion packet version", 0x8000 | 0x4000 | 4);
377 macro_rules! return_err {
378 ($msg: expr, $err_code: expr, $data: expr) => {
380 if msg.blinding_point.is_some() {
381 return_malformed_err!($msg, INVALID_ONION_BLINDING)
384 log_info!(logger, "Failed to accept/forward incoming HTLC: {}", $msg);
385 return Err(HTLCFailureMsg::Relay(msgs::UpdateFailHTLC {
386 channel_id: msg.channel_id,
387 htlc_id: msg.htlc_id,
388 reason: HTLCFailReason::reason($err_code, $data.to_vec())
389 .get_encrypted_failure_packet(&shared_secret, &None),
395 let next_hop = match onion_utils::decode_next_payment_hop(
396 shared_secret, &msg.onion_routing_packet.hop_data[..], msg.onion_routing_packet.hmac,
397 msg.payment_hash, msg.blinding_point, node_signer
400 Err(onion_utils::OnionDecodeErr::Malformed { err_msg, err_code }) => {
401 return_malformed_err!(err_msg, err_code);
403 Err(onion_utils::OnionDecodeErr::Relay { err_msg, err_code }) => {
404 return_err!(err_msg, err_code, &[0; 0]);
408 let next_packet_details = match next_hop {
409 onion_utils::Hop::Forward {
410 next_hop_data: msgs::InboundOnionPayload::Forward {
411 short_channel_id, amt_to_forward, outgoing_cltv_value
414 let next_packet_pubkey = onion_utils::next_hop_pubkey(secp_ctx,
415 msg.onion_routing_packet.public_key.unwrap(), &shared_secret);
417 next_packet_pubkey, outgoing_scid: short_channel_id,
418 outgoing_amt_msat: amt_to_forward, outgoing_cltv_value
421 onion_utils::Hop::Forward {
422 next_hop_data: msgs::InboundOnionPayload::BlindedForward {
423 short_channel_id, ref payment_relay, ref payment_constraints, ref features, ..
426 let (amt_to_forward, outgoing_cltv_value) = match check_blinded_forward(
427 msg.amount_msat, msg.cltv_expiry, &payment_relay, &payment_constraints, &features
429 Ok((amt, cltv)) => (amt, cltv),
431 return_err!("Underflow calculating outbound amount or cltv value for blinded forward",
432 INVALID_ONION_BLINDING, &[0; 32]);
435 let next_packet_pubkey = onion_utils::next_hop_pubkey(&secp_ctx,
436 msg.onion_routing_packet.public_key.unwrap(), &shared_secret);
438 next_packet_pubkey, outgoing_scid: short_channel_id, outgoing_amt_msat: amt_to_forward,
442 onion_utils::Hop::Receive { .. } => return Ok((next_hop, shared_secret, None)),
443 onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::Receive { .. }, .. } |
444 onion_utils::Hop::Forward { next_hop_data: msgs::InboundOnionPayload::BlindedReceive { .. }, .. } =>
446 return_err!("Final Node OnionHopData provided for us as an intermediary node", 0x4000 | 22, &[0; 0]);
450 Ok((next_hop, shared_secret, Some(next_packet_details)))
453 pub(super) fn check_incoming_htlc_cltv(
454 cur_height: u32, outgoing_cltv_value: u32, cltv_expiry: u32
455 ) -> Result<(), (&'static str, u16)> {
456 if (cltv_expiry as u64) < (outgoing_cltv_value) as u64 + MIN_CLTV_EXPIRY_DELTA as u64 {
458 "Forwarding node has tampered with the intended HTLC values or origin node has an obsolete cltv_expiry_delta",
459 0x1000 | 13, // incorrect_cltv_expiry
462 // Theoretically, channel counterparty shouldn't send us a HTLC expiring now,
463 // but we want to be robust wrt to counterparty packet sanitization (see
464 // HTLC_FAIL_BACK_BUFFER rationale).
465 if cltv_expiry <= cur_height + HTLC_FAIL_BACK_BUFFER as u32 { // expiry_too_soon
466 return Err(("CLTV expiry is too close", 0x1000 | 14));
468 if cltv_expiry > cur_height + CLTV_FAR_FAR_AWAY as u32 { // expiry_too_far
469 return Err(("CLTV expiry is too far in the future", 21));
471 // If the HTLC expires ~now, don't bother trying to forward it to our
472 // counterparty. They should fail it anyway, but we don't want to bother with
473 // the round-trips or risk them deciding they definitely want the HTLC and
474 // force-closing to ensure they get it if we're offline.
475 // We previously had a much more aggressive check here which tried to ensure
476 // our counterparty receives an HTLC which has *our* risk threshold met on it,
477 // but there is no need to do that, and since we're a bit conservative with our
478 // risk threshold it just results in failing to forward payments.
479 if (outgoing_cltv_value) as u64 <= (cur_height + LATENCY_GRACE_PERIOD_BLOCKS) as u64 {
480 return Err(("Outgoing CLTV value is too soon", 0x1000 | 14));
488 use bitcoin::hashes::Hash;
489 use bitcoin::hashes::sha256::Hash as Sha256;
490 use bitcoin::secp256k1::{PublicKey, SecretKey};
491 use crate::ln::{PaymentPreimage, PaymentHash, PaymentSecret};
492 use crate::ln::ChannelId;
493 use crate::ln::channelmanager::RecipientOnionFields;
494 use crate::ln::features::{ChannelFeatures, NodeFeatures};
496 use crate::ln::onion_utils::create_payment_onion;
497 use crate::routing::router::{Path, RouteHop};
498 use crate::util::test_utils;
501 fn test_peel_payment_onion() {
503 let secp_ctx = Secp256k1::new();
505 let bob = crate::sign::KeysManager::new(&[2; 32], 42, 42);
506 let bob_pk = PublicKey::from_secret_key(&secp_ctx, &bob.get_node_secret_key());
507 let charlie = crate::sign::KeysManager::new(&[3; 32], 42, 42);
508 let charlie_pk = PublicKey::from_secret_key(&secp_ctx, &charlie.get_node_secret_key());
510 let (session_priv, total_amt_msat, cur_height, recipient_onion, preimage, payment_hash,
511 prng_seed, hops, recipient_amount, pay_secret) = payment_onion_args(bob_pk, charlie_pk);
518 let (onion, amount_msat, cltv_expiry) = create_payment_onion(
519 &secp_ctx, &path, &session_priv, total_amt_msat, recipient_onion, cur_height,
520 &payment_hash, &Some(preimage), prng_seed
523 let msg = make_update_add_msg(amount_msat, cltv_expiry, payment_hash, onion);
524 let logger = test_utils::TestLogger::with_id("bob".to_string());
526 let peeled = peel_payment_onion(&msg, &&bob, &&logger, &secp_ctx, cur_height, true, false)
527 .map_err(|e| e.msg).unwrap();
529 let next_onion = match peeled.routing {
530 PendingHTLCRouting::Forward { onion_packet, .. } => {
533 _ => panic!("expected a forwarded onion"),
536 let msg2 = make_update_add_msg(amount_msat, cltv_expiry, payment_hash, next_onion);
537 let peeled2 = peel_payment_onion(&msg2, &&charlie, &&logger, &secp_ctx, cur_height, true, false)
538 .map_err(|e| e.msg).unwrap();
540 match peeled2.routing {
541 PendingHTLCRouting::ReceiveKeysend { payment_preimage, payment_data, incoming_cltv_expiry, .. } => {
542 assert_eq!(payment_preimage, preimage);
543 assert_eq!(peeled2.outgoing_amt_msat, recipient_amount);
544 assert_eq!(incoming_cltv_expiry, peeled2.outgoing_cltv_value);
545 let msgs::FinalOnionHopData{total_msat, payment_secret} = payment_data.unwrap();
546 assert_eq!(total_msat, total_amt_msat);
547 assert_eq!(payment_secret, pay_secret);
549 _ => panic!("expected a received keysend"),
553 fn make_update_add_msg(
554 amount_msat: u64, cltv_expiry: u32, payment_hash: PaymentHash,
555 onion_routing_packet: msgs::OnionPacket
556 ) -> msgs::UpdateAddHTLC {
557 msgs::UpdateAddHTLC {
558 channel_id: ChannelId::from_bytes([0; 32]),
563 onion_routing_packet,
564 skimmed_fee_msat: None,
565 blinding_point: None,
569 fn payment_onion_args(hop_pk: PublicKey, recipient_pk: PublicKey) -> (
570 SecretKey, u64, u32, RecipientOnionFields, PaymentPreimage, PaymentHash, [u8; 32],
571 Vec<RouteHop>, u64, PaymentSecret,
573 let session_priv_bytes = [42; 32];
574 let session_priv = SecretKey::from_slice(&session_priv_bytes).unwrap();
575 let total_amt_msat = 1000;
576 let cur_height = 1000;
577 let pay_secret = PaymentSecret([99; 32]);
578 let recipient_onion = RecipientOnionFields::secret_only(pay_secret);
579 let preimage_bytes = [43; 32];
580 let preimage = PaymentPreimage(preimage_bytes);
581 let rhash_bytes = Sha256::hash(&preimage_bytes).to_byte_array();
582 let payment_hash = PaymentHash(rhash_bytes);
583 let prng_seed = [44; 32];
585 // make a route alice -> bob -> charlie
587 let recipient_amount = total_amt_msat - hop_fee;
592 cltv_expiry_delta: 42,
594 node_features: NodeFeatures::empty(),
595 channel_features: ChannelFeatures::empty(),
596 maybe_announced_channel: false,
599 pubkey: recipient_pk,
600 fee_msat: recipient_amount,
601 cltv_expiry_delta: 42,
603 node_features: NodeFeatures::empty(),
604 channel_features: ChannelFeatures::empty(),
605 maybe_announced_channel: false,
609 (session_priv, total_amt_msat, cur_height, recipient_onion, preimage, payment_hash,
610 prng_seed, hops, recipient_amount, pay_secret)