Support including invreqs when building onion payloads

Add a new invoice request parameter to onion_utils::build_onion_payloads.
As of this commit it will always be passed in as None, to be updated in future
commits.

Per <lightning/bolts#1149>, when paying a static
invoice we need to include our original invoice request in the HTLC onion since
the recipient wouldn't have received it previously.

Author: valentinewallace

lightning/src/ln/blinded_payment_tests.rs

@@ -318,7 +318,7 @@ fn do_forward_checks_failure(check: ForwardCheckFail, intro_fails: bool) {
 					let onion_keys = onion_utils::construct_onion_keys(&Secp256k1::new(), &route.paths[0], &session_priv).unwrap();
 					let cur_height = nodes[0].best_block_info().1;
 					let (mut onion_payloads, ..) = onion_utils::build_onion_payloads(
-						&route.paths[0], amt_msat, &recipient_onion_fields, cur_height, &None).unwrap();
+						&route.paths[0], amt_msat, &recipient_onion_fields, cur_height, &None, None).unwrap();
 					// Remove the receive payload so the blinded forward payload is encoded as a final payload
 					// (i.e. next_hop_hmac == [0; 32])
 					onion_payloads.pop();
@@ -897,7 +897,7 @@ fn do_multi_hop_receiver_fail(check: ReceiveCheckFail) {
 			let cur_height = nodes[0].best_block_info().1;
 			let recipient_onion_fields = RecipientOnionFields::spontaneous_empty();
 			let (mut onion_payloads, ..) = onion_utils::build_onion_payloads(
-				&route.paths[0], amt_msat, &recipient_onion_fields, cur_height, &None).unwrap();
+				&route.paths[0], amt_msat, &recipient_onion_fields, cur_height, &None, None).unwrap();
 
 			let update_add = &mut payment_event_1_2.msgs[0];
 			onion_payloads.last_mut().map(|p| {

lightning/src/ln/functional_tests.rs

@@ -1438,7 +1438,7 @@ fn test_fee_spike_violation_fails_htlc() {
 	let onion_keys = onion_utils::construct_onion_keys(&secp_ctx, &route.paths[0], &session_priv).unwrap();
 	let recipient_onion_fields = RecipientOnionFields::secret_only(payment_secret);
 	let (onion_payloads, htlc_msat, htlc_cltv) = onion_utils::build_onion_payloads(&route.paths[0],
-		3460001, &recipient_onion_fields, cur_height, &None).unwrap();
+		3460001, &recipient_onion_fields, cur_height, &None, None).unwrap();
 	let onion_packet = onion_utils::construct_onion_packet(onion_payloads, onion_keys, [0; 32], &payment_hash).unwrap();
 	let msg = msgs::UpdateAddHTLC {
 		channel_id: chan.2,
@@ -1637,7 +1637,7 @@ fn test_chan_reserve_violation_inbound_htlc_outbound_channel() {
 	let onion_keys = onion_utils::construct_onion_keys(&secp_ctx, &route.paths[0], &session_priv).unwrap();
 	let recipient_onion_fields = RecipientOnionFields::secret_only(payment_secret);
 	let (onion_payloads, htlc_msat, htlc_cltv) = onion_utils::build_onion_payloads(&route.paths[0],
-		700_000, &recipient_onion_fields, cur_height, &None).unwrap();
+		700_000, &recipient_onion_fields, cur_height, &None, None).unwrap();
 	let onion_packet = onion_utils::construct_onion_packet(onion_payloads, onion_keys, [0; 32], &payment_hash).unwrap();
 	let msg = msgs::UpdateAddHTLC {
 		channel_id: chan.2,
@@ -1817,7 +1817,7 @@ fn test_chan_reserve_violation_inbound_htlc_inbound_chan() {
 	let onion_keys = onion_utils::construct_onion_keys(&secp_ctx, &route_2.paths[0], &session_priv).unwrap();
 	let recipient_onion_fields = RecipientOnionFields::spontaneous_empty();
 	let (onion_payloads, htlc_msat, htlc_cltv) = onion_utils::build_onion_payloads(
-		&route_2.paths[0], recv_value_2, &recipient_onion_fields, cur_height, &None).unwrap();
+		&route_2.paths[0], recv_value_2, &recipient_onion_fields, cur_height, &None, None).unwrap();
 	let onion_packet = onion_utils::construct_onion_packet(onion_payloads, onion_keys, [0; 32], &our_payment_hash_1).unwrap();
 	let msg = msgs::UpdateAddHTLC {
 		channel_id: chan.2,
@@ -3556,7 +3556,7 @@ fn fail_backward_pending_htlc_upon_channel_failure() {
 		let current_height = nodes[1].node.best_block.read().unwrap().height + 1;
 		let recipient_onion_fields = RecipientOnionFields::secret_only(payment_secret);
 		let (onion_payloads, _amount_msat, cltv_expiry) = onion_utils::build_onion_payloads(
-			&route.paths[0], 50_000, &recipient_onion_fields, current_height, &None).unwrap();
+			&route.paths[0], 50_000, &recipient_onion_fields, current_height, &None, None).unwrap();
 		let onion_keys = onion_utils::construct_onion_keys(&secp_ctx, &route.paths[0], &session_priv).unwrap();
 		let onion_routing_packet = onion_utils::construct_onion_packet(onion_payloads, onion_keys, [0; 32], &payment_hash).unwrap();
 
@@ -6548,7 +6548,7 @@ fn test_update_add_htlc_bolt2_receiver_check_max_htlc_limit() {
 	let onion_keys = onion_utils::construct_onion_keys(&Secp256k1::signing_only(), &route.paths[0], &session_priv).unwrap();
 	let recipient_onion_fields = RecipientOnionFields::secret_only(our_payment_secret);
 	let (onion_payloads, _htlc_msat, htlc_cltv) = onion_utils::build_onion_payloads(
-		&route.paths[0], send_amt, &recipient_onion_fields, cur_height, &None).unwrap();
+		&route.paths[0], send_amt, &recipient_onion_fields, cur_height, &None, None).unwrap();
 	let onion_packet = onion_utils::construct_onion_packet(onion_payloads, onion_keys, [0; 32], &our_payment_hash).unwrap();
 
 	let mut msg = msgs::UpdateAddHTLC {
@@ -8291,7 +8291,7 @@ fn test_onion_value_mpp_set_calculation() {
 			let mut onion_keys = onion_utils::construct_onion_keys(&Secp256k1::new(), &route.paths[0], &session_priv).unwrap();
 			let recipient_onion_fields = RecipientOnionFields::secret_only(our_payment_secret);
 			let (mut onion_payloads, _, _) = onion_utils::build_onion_payloads(&route.paths[0], 100_000,
-				&recipient_onion_fields, height + 1, &None).unwrap();
+				&recipient_onion_fields, height + 1, &None, None).unwrap();
 			// Edit amt_to_forward to simulate the sender having set
 			// the final amount and the routing node taking less fee
 			if let msgs::OutboundOnionPayload::Receive {

lightning/src/ln/max_payment_path_len_tests.rs

@@ -276,7 +276,7 @@ fn blinded_path_with_custom_tlv() {
 	let reserved_packet_bytes_without_custom_tlv: usize = onion_utils::build_onion_payloads(
 		&route.paths[0], MIN_FINAL_VALUE_ESTIMATE_WITH_OVERPAY,
 		&RecipientOnionFields::spontaneous_empty(),
-		nodes[0].best_block_info().1 + DEFAULT_MAX_TOTAL_CLTV_EXPIRY_DELTA, &None
+		nodes[0].best_block_info().1 + DEFAULT_MAX_TOTAL_CLTV_EXPIRY_DELTA, &None, None
 	)
 		.unwrap()
 		.0

lightning/src/ln/onion_payment.rs

@@ -541,7 +541,7 @@ mod tests {
 		let path = Path { hops, blinded_tail: None, };
 		let onion_keys = super::onion_utils::construct_onion_keys(&secp_ctx, &path, &session_priv).unwrap();
 		let (onion_payloads, ..) = super::onion_utils::build_onion_payloads(
-			&path, total_amt_msat, &recipient_onion, cur_height + 1, &Some(keysend_preimage)
+			&path, total_amt_msat, &recipient_onion, cur_height + 1, &Some(keysend_preimage), None
 		).unwrap();
 
 		assert!(super::onion_utils::construct_onion_packet(

lightning/src/ln/onion_route_tests.rs

@@ -356,7 +356,7 @@ fn test_onion_failure() {
 		let onion_keys = onion_utils::construct_onion_keys(&Secp256k1::new(), &route.paths[0], &session_priv).unwrap();
 		let recipient_onion_fields = RecipientOnionFields::spontaneous_empty();
 		let (mut onion_payloads, _htlc_msat, _htlc_cltv) = onion_utils::build_onion_payloads(
-			&route.paths[0], 40000, &recipient_onion_fields, cur_height, &None).unwrap();
+			&route.paths[0], 40000, &recipient_onion_fields, cur_height, &None, None).unwrap();
 		let mut new_payloads = Vec::new();
 		for payload in onion_payloads.drain(..) {
 			new_payloads.push(BogusOnionHopData::new(payload));
@@ -375,7 +375,7 @@ fn test_onion_failure() {
 		let onion_keys = onion_utils::construct_onion_keys(&Secp256k1::new(), &route.paths[0], &session_priv).unwrap();
 		let recipient_onion_fields = RecipientOnionFields::spontaneous_empty();
 		let (mut onion_payloads, _htlc_msat, _htlc_cltv) = onion_utils::build_onion_payloads(
-			&route.paths[0], 40000, &recipient_onion_fields, cur_height, &None).unwrap();
+			&route.paths[0], 40000, &recipient_onion_fields, cur_height, &None, None).unwrap();
 		let mut new_payloads = Vec::new();
 		for payload in onion_payloads.drain(..) {
 			new_payloads.push(BogusOnionHopData::new(payload));
@@ -627,7 +627,7 @@ fn test_onion_failure() {
 		let onion_keys = onion_utils::construct_onion_keys(&Secp256k1::new(), &route.paths[0], &session_priv).unwrap();
 		let recipient_onion_fields = RecipientOnionFields::spontaneous_empty();
 		let (onion_payloads, _, htlc_cltv) = onion_utils::build_onion_payloads(
-			&route.paths[0], 40000, &recipient_onion_fields, height, &None).unwrap();
+			&route.paths[0], 40000, &recipient_onion_fields, height, &None, None).unwrap();
 		let onion_packet = onion_utils::construct_onion_packet(onion_payloads, onion_keys, [0; 32], &payment_hash).unwrap();
 		msg.cltv_expiry = htlc_cltv;
 		msg.onion_routing_packet = onion_packet;
@@ -964,7 +964,7 @@ fn test_always_create_tlv_format_onion_payloads() {
 	let cur_height = nodes[0].best_block_info().1 + 1;
 	let recipient_onion_fields = RecipientOnionFields::spontaneous_empty();
 	let (onion_payloads, _htlc_msat, _htlc_cltv) = onion_utils::build_onion_payloads(
-		&route.paths[0], 40000, &recipient_onion_fields, cur_height, &None).unwrap();
+		&route.paths[0], 40000, &recipient_onion_fields, cur_height, &None, None).unwrap();
 
 	match onion_payloads[0] {
 		msgs::OutboundOnionPayload::Forward {..} => {},
@@ -1221,7 +1221,7 @@ fn test_phantom_invalid_onion_payload() {
 					let recipient_onion_fields = RecipientOnionFields::secret_only(payment_secret);
 					let (mut onion_payloads, _, _) = onion_utils::build_onion_payloads(
 						&route.paths[0], msgs::MAX_VALUE_MSAT + 1,
-						&recipient_onion_fields, height + 1, &None).unwrap();
+						&recipient_onion_fields, height + 1, &None, None).unwrap();
 					// We only want to construct the onion packet for the last hop, not the entire route, so
 					// remove the first hop's payload and its keys.
 					onion_keys.remove(0);

lightning/src/ln/onion_utils.rs

@@ -13,6 +13,7 @@ use crate::crypto::streams::ChaChaReader;
 use crate::ln::channel::TOTAL_BITCOIN_SUPPLY_SATOSHIS;
 use crate::ln::channelmanager::{HTLCSource, RecipientOnionFields};
 use crate::ln::msgs;
+use crate::offers::invoice_request::InvoiceRequest;
 use crate::routing::gossip::NetworkUpdate;
 use crate::routing::router::{Path, RouteHop, RouteParameters};
 use crate::sign::NodeSigner;
@@ -179,6 +180,7 @@ pub(super) fn construct_onion_keys<T: secp256k1::Signing>(
 pub(super) fn build_onion_payloads<'a>(
 	path: &'a Path, total_msat: u64, recipient_onion: &'a RecipientOnionFields,
 	starting_htlc_offset: u32, keysend_preimage: &Option<PaymentPreimage>,
+	invoice_request: Option<&'a InvoiceRequest>,
 ) -> Result<(Vec<msgs::OutboundOnionPayload<'a>>, u64, u32), APIError> {
 	let mut res: Vec<msgs::OutboundOnionPayload> = Vec::with_capacity(
 		path.hops.len() + path.blinded_tail.as_ref().map_or(0, |t| t.hops.len()),
@@ -197,6 +199,7 @@ pub(super) fn build_onion_payloads<'a>(
 		recipient_onion,
 		starting_htlc_offset,
 		keysend_preimage,
+		invoice_request,
 		|action, payload| match action {
 			PayloadCallbackAction::PushBack => res.push(payload),
 			PayloadCallbackAction::PushFront => res.insert(0, payload),
@@ -218,7 +221,8 @@ enum PayloadCallbackAction {
 fn build_onion_payloads_callback<'a, H, B, F>(
 	hops: H, mut blinded_tail: Option<BlindedTailHopIter<'a, B>>, total_msat: u64,
 	recipient_onion: &'a RecipientOnionFields, starting_htlc_offset: u32,
-	keysend_preimage: &Option<PaymentPreimage>, mut callback: F,
+	keysend_preimage: &Option<PaymentPreimage>, invoice_request: Option<&'a InvoiceRequest>,
+	mut callback: F,
 ) -> Result<(u64, u32), APIError>
 where
 	H: DoubleEndedIterator<Item = &'a RouteHop>,
@@ -262,7 +266,7 @@ where
 								encrypted_tlvs: &blinded_hop.encrypted_payload,
 								intro_node_blinding_point: blinding_point.take(),
 								keysend_preimage: *keysend_preimage,
-								invoice_request: None,
+								invoice_request,
 								custom_tlvs: &recipient_onion.custom_tlvs,
 							},
 						);
@@ -363,6 +367,7 @@ pub(crate) fn set_max_path_length(
 		&recipient_onion,
 		best_block_height,
 		&keysend_preimage,
+		None,
 		|_, payload| {
 			num_reserved_bytes = num_reserved_bytes
 				.saturating_add(payload.serialized_length())
@@ -1169,6 +1174,7 @@ pub fn create_payment_onion<T: secp256k1::Signing>(
 		recipient_onion,
 		cur_block_height,
 		keysend_preimage,
+		None,
 	)?;
 	let onion_packet = construct_onion_packet(onion_payloads, onion_keys, prng_seed, payment_hash)
 		.map_err(|_| APIError::InvalidRoute {