Return Trampoline payloads in build_onion_payloads

Author: arik-so

lightning/src/ln/functional_tests.rs

@@ -1437,7 +1437,7 @@ 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],
+	let (onion_payloads, _, htlc_msat, htlc_cltv) = onion_utils::build_onion_payloads(&route.paths[0],
 		3460001, &recipient_onion_fields, cur_height, &None).unwrap();
 	let onion_packet = onion_utils::construct_onion_packet(onion_payloads, onion_keys, [0; 32], &payment_hash).unwrap();
 	let msg = msgs::UpdateAddHTLC {
@@ -1636,7 +1636,7 @@ fn test_chan_reserve_violation_inbound_htlc_outbound_channel() {
 	let cur_height = nodes[1].node.best_block.read().unwrap().height + 1;
 	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],
+	let (onion_payloads, _, htlc_msat, htlc_cltv) = onion_utils::build_onion_payloads(&route.paths[0],
 		700_000, &recipient_onion_fields, cur_height, &None).unwrap();
 	let onion_packet = onion_utils::construct_onion_packet(onion_payloads, onion_keys, [0; 32], &payment_hash).unwrap();
 	let msg = msgs::UpdateAddHTLC {
@@ -1816,7 +1816,7 @@ fn test_chan_reserve_violation_inbound_htlc_inbound_chan() {
 	let cur_height = nodes[0].node.best_block.read().unwrap().height + 1;
 	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(
+	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();
 	let onion_packet = onion_utils::construct_onion_packet(onion_payloads, onion_keys, [0; 32], &our_payment_hash_1).unwrap();
 	let msg = msgs::UpdateAddHTLC {
@@ -3555,7 +3555,7 @@ fn fail_backward_pending_htlc_upon_channel_failure() {
 		let session_priv = SecretKey::from_slice(&[42; 32]).unwrap();
 		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(
+		let (onion_payloads, __trampoline_payloads, amount_msat, cltv_expiry) = onion_utils::build_onion_payloads(
 			&route.paths[0], 50_000, &recipient_onion_fields, current_height, &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();
@@ -6547,7 +6547,7 @@ fn test_update_add_htlc_bolt2_receiver_check_max_htlc_limit() {
 	let cur_height = nodes[0].node.best_block.read().unwrap().height + 1;
 	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(
+	let (onion_payloads, _trampoline_payloads, _htlc_msat, htlc_cltv) = onion_utils::build_onion_payloads(
 		&route.paths[0], send_amt, &recipient_onion_fields, cur_height, &None).unwrap();
 	let onion_packet = onion_utils::construct_onion_packet(onion_payloads, onion_keys, [0; 32], &our_payment_hash).unwrap();
 
@@ -8290,7 +8290,7 @@ fn test_onion_value_mpp_set_calculation() {
 			let session_priv = SecretKey::from_slice(&session_priv).unwrap();
 			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,
+			let (mut onion_payloads, _, _, _) = onion_utils::build_onion_payloads(&route.paths[0], 100_000,
 				&recipient_onion_fields, height + 1, &None).unwrap();
 			// Edit amt_to_forward to simulate the sender having set
 			// the final amount and the routing node taking less fee

lightning/src/ln/onion_route_tests.rs

@@ -355,7 +355,7 @@ fn test_onion_failure() {
 		let cur_height = nodes[0].best_block_info().1 + 1;
 		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(
+		let (mut onion_payloads, _trampoline_payloads, _htlc_msat, _htlc_cltv) = onion_utils::build_onion_payloads(
 			&route.paths[0], 40000, &recipient_onion_fields, cur_height, &None).unwrap();
 		let mut new_payloads = Vec::new();
 		for payload in onion_payloads.drain(..) {
@@ -374,7 +374,7 @@ fn test_onion_failure() {
 		let cur_height = nodes[0].best_block_info().1 + 1;
 		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(
+		let (mut onion_payloads, _trampoline_payloads, _htlc_msat, _htlc_cltv) = onion_utils::build_onion_payloads(
 			&route.paths[0], 40000, &recipient_onion_fields, cur_height, &None).unwrap();
 		let mut new_payloads = Vec::new();
 		for payload in onion_payloads.drain(..) {
@@ -626,7 +626,7 @@ fn test_onion_failure() {
 		route.paths[0].hops[1].cltv_expiry_delta += CLTV_FAR_FAR_AWAY + route.paths[0].hops[0].cltv_expiry_delta + 1;
 		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(
+		let (onion_payloads, _, _, htlc_cltv) = onion_utils::build_onion_payloads(
 			&route.paths[0], 40000, &recipient_onion_fields, height, &None).unwrap();
 		let onion_packet = onion_utils::construct_onion_packet(onion_payloads, onion_keys, [0; 32], &payment_hash).unwrap();
 		msg.cltv_expiry = htlc_cltv;
@@ -963,7 +963,7 @@ 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(
+	let (onion_payloads, _trampoline_payloads, _htlc_msat, _htlc_cltv) = onion_utils::build_onion_payloads(
 		&route.paths[0], 40000, &recipient_onion_fields, cur_height, &None).unwrap();
 
 	match onion_payloads[0] {
@@ -1219,7 +1219,7 @@ fn test_phantom_invalid_onion_payload() {
 					let session_priv = SecretKey::from_slice(&session_priv).unwrap();
 					let mut onion_keys = onion_utils::construct_onion_keys(&Secp256k1::new(), &route.paths[0], &session_priv).unwrap();
 					let recipient_onion_fields = RecipientOnionFields::secret_only(payment_secret);
-					let (mut onion_payloads, _, _) = onion_utils::build_onion_payloads(
+					let (mut onion_payloads, _, _, _) = onion_utils::build_onion_payloads(
 						&route.paths[0], msgs::MAX_VALUE_MSAT + 1,
 						&recipient_onion_fields, height + 1, &None).unwrap();
 					// We only want to construct the onion packet for the last hop, not the entire route, so

lightning/src/ln/onion_utils.rs

@@ -15,7 +15,7 @@ use crate::ln::channelmanager::{HTLCSource, RecipientOnionFields};
 use crate::ln::msgs;
 use crate::routing::gossip::NetworkUpdate;
 use crate::routing::router::{Path, RouteHop, RouteParameters, TrampolineHop};
-use crate::sign::NodeSigner;
+use crate::sign::{EntropySource, NodeSigner};
 use crate::types::features::{ChannelFeatures, NodeFeatures};
 use crate::types::payment::{PaymentHash, PaymentPreimage};
 use crate::util::errors::{self, APIError};
@@ -33,7 +33,7 @@ use bitcoin::secp256k1::{PublicKey, Scalar, Secp256k1, SecretKey};
 
 use crate::io::{Cursor, Read};
 use core::ops::Deref;
-
+use crate::blinded_path::payment::BlindedPaymentPath;
 #[allow(unused_imports)]
 use crate::prelude::*;
 
@@ -185,6 +185,13 @@ fn build_trampoline_onion_payloads<'a>(
 	let blinded_tail = path.blinded_tail.as_ref().ok_or(APIError::InvalidRoute {
 		err: "Routes using Trampoline must terminate blindly.".to_string(),
 	})?;
+
+	if !blinded_tail.final_hop_supports_trampoline {
+		// if the final hop does not support Trampoline, we need to generate blinded tails
+		// here instead
+		debug_assert!(false);
+	}
+
 	let blinded_tail_with_hop_iter = BlindedTailHopIter {
 		hops: blinded_tail.hops.iter(),
 		blinding_point: blinded_tail.blinding_point,
@@ -295,30 +302,42 @@ where
 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>,
-) -> Result<(Vec<msgs::OutboundOnionPayload<'a>>, u64, u32), APIError> {
+) -> Result<(Vec<msgs::OutboundOnionPayload<'a>>, Vec<msgs::OutboundTrampolinePayload<'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()),
 	);
-	let blinded_tail_with_hop_iter = path.blinded_tail.as_ref().map(|bt| BlindedTailHopIter {
-		hops: bt.hops.iter(),
-		blinding_point: bt.blinding_point,
-		final_value_msat: bt.final_value_msat,
-		excess_final_cltv_expiry_delta: bt.excess_final_cltv_expiry_delta,
-	});
+
+	let mut non_trampoline_total_msat = total_msat;
+	let mut non_trampoline_starting_htlc_offset = starting_htlc_offset;
+
+	let (blinded_tail_with_hop_iter, trampoline_payloads) = if path.trampoline_hops.len() > 0 {
+		let trampoline_payload_details = build_trampoline_onion_payloads(path, total_msat, recipient_onion, starting_htlc_offset, keysend_preimage)?;
+		non_trampoline_total_msat = trampoline_payload_details.1;
+		non_trampoline_starting_htlc_offset = trampoline_payload_details.2;
+		(None, trampoline_payload_details.0)
+	} else {
+		let blinded_tail_with_hop_iter = path.blinded_tail.as_ref().map(|bt| BlindedTailHopIter {
+			hops: bt.hops.iter(),
+			blinding_point: bt.blinding_point,
+			final_value_msat: bt.final_value_msat,
+			excess_final_cltv_expiry_delta: bt.excess_final_cltv_expiry_delta,
+		});
+		(blinded_tail_with_hop_iter, vec![])
+	};
 
 	let (value_msat, cltv) = build_onion_payloads_callback(
 		path.hops.iter(),
 		blinded_tail_with_hop_iter,
-		total_msat,
+		non_trampoline_total_msat,
 		recipient_onion,
-		starting_htlc_offset,
+		non_trampoline_starting_htlc_offset,
 		keysend_preimage,
 		|action, payload| match action {
 			PayloadCallbackAction::PushBack => res.push(payload),
 			PayloadCallbackAction::PushFront => res.insert(0, payload),
 		},
 	)?;
-	Ok((res, value_msat, cltv))
+	Ok((res, trampoline_payloads, value_msat, cltv))
 }
 
 struct BlindedTailHopIter<'a, I: Iterator<Item = &'a BlindedHop>> {
@@ -1278,7 +1297,7 @@ pub fn create_payment_onion<T: secp256k1::Signing>(
 	let onion_keys = construct_onion_keys(&secp_ctx, &path, &session_priv).map_err(|_| {
 		APIError::InvalidRoute { err: "Pubkey along hop was maliciously selected".to_owned() }
 	})?;
-	let (onion_payloads, htlc_msat, htlc_cltv) = build_onion_payloads(
+	let (onion_payloads, _, htlc_msat, htlc_cltv) = build_onion_payloads(
 		&path,
 		total_msat,
 		recipient_onion,