Replace OnionHopData with OutboundPayload for outbound onions

Follows on from the previous commit, see its message

Author: valentinewallace

lightning/src/ln/functional_tests.rs

@@ -8039,7 +8039,9 @@ fn test_onion_value_mpp_set_calculation() {
 				RecipientOnionFields::secret_only(our_payment_secret), height + 1, &None).unwrap();
 			// Edit amt_to_forward to simulate the sender having set
 			// the final amount and the routing node taking less fee
-			onion_payloads[1].amt_to_forward = 99_000;
+			if let msgs::OutboundPayload::Receive { ref mut amt_msat, .. } = onion_payloads[1] {
+				*amt_msat = 99_000;
+			} else { panic!() }
 			let new_onion_packet = onion_utils::construct_onion_packet(onion_payloads, onion_keys, [0; 32], &our_payment_hash).unwrap();
 			payment_event.msgs[0].onion_routing_packet = new_onion_packet;
 		}

lightning/src/ln/msgs.rs

@@ -1441,25 +1441,21 @@ mod fuzzy_internal_msgs {
 		},
 	}
 
-	pub(crate) enum OnionHopDataFormat {
-		NonFinalNode {
+	pub(crate) enum OutboundPayload {
+		Forward {
 			short_channel_id: u64,
+			amt_to_forward: u64,
+			outgoing_cltv_value: u32,
 		},
-		FinalNode {
+		Receive {
 			payment_data: Option<FinalOnionHopData>,
 			payment_metadata: Option<Vec<u8>>,
 			keysend_preimage: Option<PaymentPreimage>,
+			amt_msat: u64,
+			outgoing_cltv_value: u32,
 		},
 	}
 
-	pub struct OnionHopData {
-		pub(crate) format: OnionHopDataFormat,
-		/// The value, in msat, of the payment after this hop's fee is deducted.
-		/// Message serialization may panic if this value is more than 21 million Bitcoin.
-		pub(crate) amt_to_forward: u64,
-		pub(crate) outgoing_cltv_value: u32,
-	}
-
 	pub struct DecodedOnionErrorPacket {
 		pub(crate) hmac: [u8; 32],
 		pub(crate) failuremsg: Vec<u8>,
@@ -1966,20 +1962,22 @@ impl Readable for FinalOnionHopData {
 	}
 }
 
-impl Writeable for OnionHopData {
+impl Writeable for OutboundPayload {
 	fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
-		match self.format {
-			OnionHopDataFormat::NonFinalNode { short_channel_id } => {
+		match self {
+			Self::Forward { short_channel_id, amt_to_forward, outgoing_cltv_value } => {
 				_encode_varint_length_prefixed_tlv!(w, {
-					(2, HighZeroBytesDroppedBigSize(self.amt_to_forward), required),
-					(4, HighZeroBytesDroppedBigSize(self.outgoing_cltv_value), required),
+					(2, HighZeroBytesDroppedBigSize(*amt_to_forward), required),
+					(4, HighZeroBytesDroppedBigSize(*outgoing_cltv_value), required),
 					(6, short_channel_id, required)
 				});
 			},
-			OnionHopDataFormat::FinalNode { ref payment_data, ref payment_metadata, ref keysend_preimage } => {
+			Self::Receive {
+				ref payment_data, ref payment_metadata, ref keysend_preimage, amt_msat, outgoing_cltv_value
+			} => {
 				_encode_varint_length_prefixed_tlv!(w, {
-					(2, HighZeroBytesDroppedBigSize(self.amt_to_forward), required),
-					(4, HighZeroBytesDroppedBigSize(self.outgoing_cltv_value), required),
+					(2, HighZeroBytesDroppedBigSize(*amt_msat), required),
+					(4, HighZeroBytesDroppedBigSize(*outgoing_cltv_value), required),
 					(8, payment_data, option),
 					(16, payment_metadata.as_ref().map(|m| WithoutLength(m)), option),
 					(5482373484, keysend_preimage, option)
@@ -2454,7 +2452,7 @@ mod tests {
 	use hex;
 	use crate::ln::{PaymentPreimage, PaymentHash, PaymentSecret};
 	use crate::ln::features::{ChannelFeatures, ChannelTypeFeatures, InitFeatures, NodeFeatures};
-	use crate::ln::msgs::{self, FinalOnionHopData, OnionErrorPacket, OnionHopDataFormat};
+	use crate::ln::msgs::{self, FinalOnionHopData, OnionErrorPacket};
 	use crate::routing::gossip::{NodeAlias, NodeId};
 	use crate::util::ser::{Writeable, Readable, Hostname, TransactionU16LenLimited};
 
@@ -3537,14 +3535,12 @@ mod tests {
 
 	#[test]
 	fn encoding_nonfinal_onion_hop_data() {
-		let msg = msgs::OnionHopData {
-			format: OnionHopDataFormat::NonFinalNode {
-				short_channel_id: 0xdeadbeef1bad1dea,
-			},
+		let outbound_msg = msgs::OutboundPayload::Forward {
+			short_channel_id: 0xdeadbeef1bad1dea,
 			amt_to_forward: 0x0badf00d01020304,
 			outgoing_cltv_value: 0xffffffff,
 		};
-		let encoded_value = msg.encode();
+		let encoded_value = outbound_msg.encode();
 		let target_value = hex::decode("1a02080badf00d010203040404ffffffff0608deadbeef1bad1dea").unwrap();
 		assert_eq!(encoded_value, target_value);
 
@@ -3558,16 +3554,14 @@ mod tests {
 
 	#[test]
 	fn encoding_final_onion_hop_data() {
-		let msg = msgs::OnionHopData {
-			format: OnionHopDataFormat::FinalNode {
-				payment_data: None,
-				payment_metadata: None,
-				keysend_preimage: None,
-			},
-			amt_to_forward: 0x0badf00d01020304,
+		let outbound_msg = msgs::OutboundPayload::Receive {
+			payment_data: None,
+			payment_metadata: None,
+			keysend_preimage: None,
+			amt_msat: 0x0badf00d01020304,
 			outgoing_cltv_value: 0xffffffff,
 		};
-		let encoded_value = msg.encode();
+		let encoded_value = outbound_msg.encode();
 		let target_value = hex::decode("1002080badf00d010203040404ffffffff").unwrap();
 		assert_eq!(encoded_value, target_value);
 
@@ -3581,19 +3575,17 @@ mod tests {
 	#[test]
 	fn encoding_final_onion_hop_data_with_secret() {
 		let expected_payment_secret = PaymentSecret([0x42u8; 32]);
-		let msg = msgs::OnionHopData {
-			format: OnionHopDataFormat::FinalNode {
-				payment_data: Some(FinalOnionHopData {
-					payment_secret: expected_payment_secret,
-					total_msat: 0x1badca1f
-				}),
-				payment_metadata: None,
-				keysend_preimage: None,
-			},
-			amt_to_forward: 0x0badf00d01020304,
+		let outbound_msg = msgs::OutboundPayload::Receive {
+			payment_data: Some(FinalOnionHopData {
+				payment_secret: expected_payment_secret,
+				total_msat: 0x1badca1f
+			}),
+			payment_metadata: None,
+			keysend_preimage: None,
+			amt_msat: 0x0badf00d01020304,
 			outgoing_cltv_value: 0xffffffff,
 		};
-		let encoded_value = msg.encode();
+		let encoded_value = outbound_msg.encode();
 		let target_value = hex::decode("3602080badf00d010203040404ffffffff082442424242424242424242424242424242424242424242424242424242424242421badca1f").unwrap();
 		assert_eq!(encoded_value, target_value);
 
@@ -3765,20 +3757,18 @@ mod tests {
 	// see above test, needs to be a separate method for use of the serialization macros.
 	fn encode_big_payload() -> Result<Vec<u8>, io::Error> {
 		use crate::util::ser::HighZeroBytesDroppedBigSize;
-		let payload = msgs::OnionHopData {
-			format: OnionHopDataFormat::NonFinalNode {
-				short_channel_id: 0xdeadbeef1bad1dea,
-			},
+		let payload = msgs::OutboundPayload::Forward {
+			short_channel_id: 0xdeadbeef1bad1dea,
 			amt_to_forward: 1000,
 			outgoing_cltv_value: 0xffffffff,
 		};
 		let mut encoded_payload = Vec::new();
 		let test_bytes = vec![42u8; 1000];
-		if let OnionHopDataFormat::NonFinalNode { short_channel_id } = payload.format {
+		if let msgs::OutboundPayload::Forward { short_channel_id, amt_to_forward, outgoing_cltv_value } = payload {
 			_encode_varint_length_prefixed_tlv!(&mut encoded_payload, {
 				(1, test_bytes, required_vec),
-				(2, HighZeroBytesDroppedBigSize(payload.amt_to_forward), required),
-				(4, HighZeroBytesDroppedBigSize(payload.outgoing_cltv_value), required),
+				(2, HighZeroBytesDroppedBigSize(amt_to_forward), required),
+				(4, HighZeroBytesDroppedBigSize(outgoing_cltv_value), required),
 				(6, short_channel_id, required)
 			});
 		}

lightning/src/ln/onion_route_tests.rs

@@ -252,7 +252,7 @@ struct BogusOnionHopData {
 	data: Vec<u8>
 }
 impl BogusOnionHopData {
-	fn new(orig: msgs::OnionHopData) -> Self {
+	fn new(orig: msgs::OutboundPayload) -> Self {
 		Self { data: orig.encode() }
 	}
 }
@@ -875,15 +875,15 @@ fn test_always_create_tlv_format_onion_payloads() {
 	let (onion_payloads, _htlc_msat, _htlc_cltv) = onion_utils::build_onion_payloads(
 		&route.paths[0], 40000, RecipientOnionFields::spontaneous_empty(), cur_height, &None).unwrap();
 
-	match onion_payloads[0].format {
-		msgs::OnionHopDataFormat::NonFinalNode {..} => {},
+	match onion_payloads[0] {
+		msgs::OutboundPayload::Forward {..} => {},
 		_ => { panic!(
 			"Should have generated a `msgs::OnionHopDataFormat::NonFinalNode` payload for `hops[0]`,
 			despite that the features signals no support for variable length onions"
 		)}
 	}
-	match onion_payloads[1].format {
-		msgs::OnionHopDataFormat::FinalNode {..} => {},
+	match onion_payloads[1] {
+		msgs::OutboundPayload::Receive {..} => {},
 		_ => {panic!(
 			"Should have generated a `msgs::OnionHopDataFormat::FinalNode` payload for `hops[1]`,
 			despite that the features signals no support for variable length onions"

lightning/src/ln/onion_utils.rs

@@ -149,37 +149,37 @@ pub(super) fn construct_onion_keys<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T
 }
 
 /// returns the hop data, as well as the first-hop value_msat and CLTV value we should send.
-pub(super) fn build_onion_payloads(path: &Path, total_msat: u64, mut recipient_onion: RecipientOnionFields, starting_htlc_offset: u32, keysend_preimage: &Option<PaymentPreimage>) -> Result<(Vec<msgs::OnionHopData>, u64, u32), APIError> {
+pub(super) fn build_onion_payloads(path: &Path, total_msat: u64, mut recipient_onion: RecipientOnionFields, starting_htlc_offset: u32, keysend_preimage: &Option<PaymentPreimage>) -> Result<(Vec<msgs::OutboundPayload>, u64, u32), APIError> {
 	let mut cur_value_msat = 0u64;
 	let mut cur_cltv = starting_htlc_offset;
 	let mut last_short_channel_id = 0;
-	let mut res: Vec<msgs::OnionHopData> = Vec::with_capacity(path.hops.len());
+	let mut res: Vec<msgs::OutboundPayload> = Vec::with_capacity(path.hops.len());
 
 	for (idx, hop) in path.hops.iter().rev().enumerate() {
 		// First hop gets special values so that it can check, on receipt, that everything is
 		// exactly as it should be (and the next hop isn't trying to probe to find out if we're
 		// the intended recipient).
 		let value_msat = if cur_value_msat == 0 { hop.fee_msat } else { cur_value_msat };
 		let cltv = if cur_cltv == starting_htlc_offset { hop.cltv_expiry_delta + starting_htlc_offset } else { cur_cltv };
-		res.insert(0, msgs::OnionHopData {
-			format: if idx == 0 {
-				msgs::OnionHopDataFormat::FinalNode {
-					payment_data: if let Some(secret) = recipient_onion.payment_secret.take() {
-						Some(msgs::FinalOnionHopData {
-							payment_secret: secret,
-							total_msat,
-						})
-					} else { None },
-					payment_metadata: recipient_onion.payment_metadata.take(),
-					keysend_preimage: *keysend_preimage,
-				}
-			} else {
-				msgs::OnionHopDataFormat::NonFinalNode {
-					short_channel_id: last_short_channel_id,
-				}
-			},
-			amt_to_forward: value_msat,
-			outgoing_cltv_value: cltv,
+		res.insert(0, if idx == 0 {
+			msgs::OutboundPayload::Receive {
+				payment_data: if let Some(secret) = recipient_onion.payment_secret.take() {
+					Some(msgs::FinalOnionHopData {
+						payment_secret: secret,
+						total_msat,
+					})
+				} else { None },
+				payment_metadata: recipient_onion.payment_metadata.take(),
+				keysend_preimage: *keysend_preimage,
+				amt_msat: value_msat,
+				outgoing_cltv_value: cltv,
+			}
+		} else {
+			msgs::OutboundPayload::Forward {
+				short_channel_id: last_short_channel_id,
+				amt_to_forward: value_msat,
+				outgoing_cltv_value: cltv,
+			}
 		});
 		cur_value_msat += hop.fee_msat;
 		if cur_value_msat >= 21000000 * 100000000 * 1000 {
@@ -208,7 +208,10 @@ fn shift_slice_right(arr: &mut [u8], amt: usize) {
 	}
 }
 
-pub(super) fn construct_onion_packet(payloads: Vec<msgs::OnionHopData>, onion_keys: Vec<OnionKeys>, prng_seed: [u8; 32], associated_data: &PaymentHash) -> Result<msgs::OnionPacket, ()> {
+pub(super) fn construct_onion_packet(
+	payloads: Vec<msgs::OutboundPayload>, onion_keys: Vec<OnionKeys>, prng_seed: [u8; 32],
+	associated_data: &PaymentHash
+) -> Result<msgs::OnionPacket, ()> {
 	let mut packet_data = [0; ONION_DATA_LEN];
 
 	let mut chacha = ChaCha20::new(&prng_seed, &[0; 8]);
@@ -988,10 +991,8 @@ mod tests {
 		// with raw hex instead of our in-memory enums, as the payloads contains custom types, and
 		// we have no way of representing that with our enums.
 		let payloads = vec!(
-			RawOnionHopData::new(msgs::OnionHopData {
-				format: msgs::OnionHopDataFormat::NonFinalNode {
-					short_channel_id: 1,
-				},
+			RawOnionHopData::new(msgs::OutboundPayload::Forward {
+				short_channel_id: 1,
 				amt_to_forward: 15000,
 				outgoing_cltv_value: 1500,
 			}),
@@ -1013,17 +1014,13 @@ mod tests {
 			RawOnionHopData {
 				data: hex::decode("52020236b00402057806080000000000000002fd02013c0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f0102030405060708090a0b0c0d0e0f").unwrap(),
 			},
-			RawOnionHopData::new(msgs::OnionHopData {
-				format: msgs::OnionHopDataFormat::NonFinalNode {
-					short_channel_id: 3,
-				},
+			RawOnionHopData::new(msgs::OutboundPayload::Forward {
+				short_channel_id: 3,
 				amt_to_forward: 12500,
 				outgoing_cltv_value: 1250,
 			}),
-			RawOnionHopData::new(msgs::OnionHopData {
-				format: msgs::OnionHopDataFormat::NonFinalNode {
-					short_channel_id: 4,
-				},
+			RawOnionHopData::new(msgs::OutboundPayload::Forward {
+				short_channel_id: 4,
 				amt_to_forward: 10000,
 				outgoing_cltv_value: 1000,
 			}),
@@ -1101,7 +1098,7 @@ mod tests {
 		data: Vec<u8>
 	}
 	impl RawOnionHopData {
-		fn new(orig: msgs::OnionHopData) -> Self {
+		fn new(orig: msgs::OutboundPayload) -> Self {
 			Self { data: orig.encode() }
 		}
 	}