Store Payee information in HTLCSource::OutboundRoute.

This stores and tracks HTLC payee information with HTLCSource info,
allowing us to provide it back to the user if the HTLC fails and
ensuring persistence by keeping it with the HTLC itself as it
passes between Channel and ChannelMonitor.

Author: TheBlueMatt

lightning/src/ln/channel.rs

@@ -5768,6 +5768,7 @@ mod tests {
 				first_hop_htlc_msat: 548,
 				payment_id: PaymentId([42; 32]),
 				payment_secret: None,
+				payee: None,
 			}
 		});
 

lightning/src/ln/channelmanager.rs

@@ -45,7 +45,7 @@ use chain::transaction::{OutPoint, TransactionData};
 use ln::{PaymentHash, PaymentPreimage, PaymentSecret};
 use ln::channel::{Channel, ChannelError, ChannelUpdateStatus, UpdateFulfillCommitFetch};
 use ln::features::{InitFeatures, NodeFeatures};
-use routing::router::{Route, RouteHop};
+use routing::router::{Payee, PaymentPathRetry, Route, RouteHop};
 use ln::msgs;
 use ln::msgs::NetAddress;
 use ln::onion_utils;
@@ -201,6 +201,7 @@ pub(crate) enum HTLCSource {
 		first_hop_htlc_msat: u64,
 		payment_id: PaymentId,
 		payment_secret: Option<PaymentSecret>,
+		payee: Option<Payee>,
 	},
 }
 #[allow(clippy::derive_hash_xor_eq)] // Our Hash is faithful to the data, we just don't have SecretKey::hash
@@ -211,13 +212,14 @@ impl core::hash::Hash for HTLCSource {
 				0u8.hash(hasher);
 				prev_hop_data.hash(hasher);
 			},
-			HTLCSource::OutboundRoute { path, session_priv, payment_id, payment_secret, first_hop_htlc_msat } => {
+			HTLCSource::OutboundRoute { path, session_priv, payment_id, payment_secret, first_hop_htlc_msat, payee } => {
 				1u8.hash(hasher);
 				path.hash(hasher);
 				session_priv[..].hash(hasher);
 				payment_id.hash(hasher);
 				payment_secret.hash(hasher);
 				first_hop_htlc_msat.hash(hasher);
+				payee.hash(hasher);
 			},
 		}
 	}
@@ -231,6 +233,7 @@ impl HTLCSource {
 			first_hop_htlc_msat: 0,
 			payment_id: PaymentId([2; 32]),
 			payment_secret: None,
+			payee: None,
 		}
 	}
 }
@@ -2021,7 +2024,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 	}
 
 	// Only public for testing, this should otherwise never be called direcly
-	pub(crate) fn send_payment_along_path(&self, path: &Vec<RouteHop>, payment_hash: &PaymentHash, payment_secret: &Option<PaymentSecret>, total_value: u64, cur_height: u32, payment_id: PaymentId, keysend_preimage: &Option<PaymentPreimage>) -> Result<(), APIError> {
+	pub(crate) fn send_payment_along_path(&self, path: &Vec<RouteHop>, payee: &Option<Payee>, payment_hash: &PaymentHash, payment_secret: &Option<PaymentSecret>, total_value: u64, cur_height: u32, payment_id: PaymentId, keysend_preimage: &Option<PaymentPreimage>) -> Result<(), APIError> {
 		log_trace!(self.logger, "Attempting to send payment for path with next hop {}", path.first().unwrap().short_channel_id);
 		let prng_seed = self.keys_manager.get_secure_random_bytes();
 		let session_priv_bytes = self.keys_manager.get_secure_random_bytes();
@@ -2071,6 +2074,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 							first_hop_htlc_msat: htlc_msat,
 							payment_id,
 							payment_secret: payment_secret.clone(),
+							payee: payee.clone(),
 						}, onion_packet, &self.logger),
 					channel_state, chan);
 
@@ -2209,7 +2213,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 		let cur_height = self.best_block.read().unwrap().height() + 1;
 		let mut results = Vec::new();
 		for path in route.paths.iter() {
-			results.push(self.send_payment_along_path(&path, &payment_hash, payment_secret, total_value, cur_height, payment_id, &keysend_preimage));
+			results.push(self.send_payment_along_path(&path, &route.payee, &payment_hash, payment_secret, total_value, cur_height, payment_id, &keysend_preimage));
 		}
 		let mut has_ok = false;
 		let mut has_err = false;
@@ -3098,14 +3102,22 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 					self.fail_htlc_backwards_internal(channel_state,
 						htlc_src, &payment_hash, HTLCFailReason::Reason { failure_code, data: onion_failure_data});
 				},
-				HTLCSource::OutboundRoute { session_priv, payment_id, path, .. } => {
+				HTLCSource::OutboundRoute { session_priv, payment_id, path, payee, .. } => {
 					let mut session_priv_bytes = [0; 32];
 					session_priv_bytes.copy_from_slice(&session_priv[..]);
 					let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 					if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(payment_id) {
-						if payment.get_mut().remove(&session_priv_bytes, Some(path.last().unwrap().fee_msat)) &&
+						let path_last_hop = path.last().expect("Outbound payments must have had a valid path");
+						if payment.get_mut().remove(&session_priv_bytes, Some(path_last_hop.fee_msat)) &&
 							!payment.get().is_fulfilled()
 						{
+							let retry = if let Some(payee_data) = payee {
+								Some(PaymentPathRetry {
+									payee: payee_data,
+									final_value_msat: path_last_hop.fee_msat,
+									final_cltv_expiry_delta: path_last_hop.cltv_expiry_delta,
+								})
+							} else { None };
 							self.pending_events.lock().unwrap().push(
 								events::Event::PaymentPathFailed {
 									payment_hash,
@@ -3114,7 +3126,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 									all_paths_failed: payment.get().remaining_parts() == 0,
 									path: path.clone(),
 									short_channel_id: None,
-									retry: None,
+									retry,
 									#[cfg(test)]
 									error_code: None,
 									#[cfg(test)]
@@ -3146,13 +3158,14 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 		// from block_connected which may run during initialization prior to the chain_monitor
 		// being fully configured. See the docs for `ChannelManagerReadArgs` for more.
 		match source {
-			HTLCSource::OutboundRoute { ref path, session_priv, payment_id, .. } => {
+			HTLCSource::OutboundRoute { ref path, session_priv, payment_id, ref payee, .. } => {
 				let mut session_priv_bytes = [0; 32];
 				session_priv_bytes.copy_from_slice(&session_priv[..]);
 				let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 				let mut all_paths_failed = false;
+				let path_last_hop = path.last().expect("Outbound payments must have had a valid path");
 				if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(payment_id) {
-					if !payment.get_mut().remove(&session_priv_bytes, Some(path.last().unwrap().fee_msat)) {
+					if !payment.get_mut().remove(&session_priv_bytes, Some(path_last_hop.fee_msat)) {
 						log_trace!(self.logger, "Received duplicative fail for HTLC with payment_hash {}", log_bytes!(payment_hash.0));
 						return;
 					}
@@ -3167,8 +3180,15 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 					log_trace!(self.logger, "Received duplicative fail for HTLC with payment_hash {}", log_bytes!(payment_hash.0));
 					return;
 				}
-				log_trace!(self.logger, "Failing outbound payment HTLC with payment_hash {}", log_bytes!(payment_hash.0));
 				mem::drop(channel_state_lock);
+				let retry = if let Some(payee_data) = payee {
+					Some(PaymentPathRetry {
+						payee: payee_data.clone(),
+						final_value_msat: path_last_hop.fee_msat,
+						final_cltv_expiry_delta: path_last_hop.cltv_expiry_delta,
+					})
+				} else { None };
+				log_trace!(self.logger, "Failing outbound payment HTLC with payment_hash {}", log_bytes!(payment_hash.0));
 				match &onion_error {
 					&HTLCFailReason::LightningError { ref err } => {
 #[cfg(test)]
@@ -3186,7 +3206,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 								all_paths_failed,
 								path: path.clone(),
 								short_channel_id,
-								retry: None,
+								retry,
 #[cfg(test)]
 								error_code: onion_error_code,
 #[cfg(test)]
@@ -3215,7 +3235,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 								all_paths_failed,
 								path: path.clone(),
 								short_channel_id: Some(path.first().unwrap().short_channel_id),
-								retry: None,
+								retry,
 #[cfg(test)]
 								error_code: Some(*failure_code),
 #[cfg(test)]
@@ -5378,12 +5398,14 @@ impl Readable for HTLCSource {
 				let mut path = Some(Vec::new());
 				let mut payment_id = None;
 				let mut payment_secret = None;
+				let mut payee = None;
 				read_tlv_fields!(reader, {
 					(0, session_priv, required),
 					(1, payment_id, option),
 					(2, first_hop_htlc_msat, required),
 					(3, payment_secret, option),
 					(4, path, vec_type),
+					(5, payee, option),
 				});
 				if payment_id.is_none() {
 					// For backwards compat, if there was no payment_id written, use the session_priv bytes
@@ -5396,6 +5418,7 @@ impl Readable for HTLCSource {
 					path: path.unwrap(),
 					payment_id: payment_id.unwrap(),
 					payment_secret,
+					payee,
 				})
 			}
 			1 => Ok(HTLCSource::PreviousHopData(Readable::read(reader)?)),
@@ -5407,7 +5430,7 @@ impl Readable for HTLCSource {
 impl Writeable for HTLCSource {
 	fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::io::Error> {
 		match self {
-			HTLCSource::OutboundRoute { ref session_priv, ref first_hop_htlc_msat, ref path, payment_id, payment_secret } => {
+			HTLCSource::OutboundRoute { ref session_priv, ref first_hop_htlc_msat, ref path, payment_id, payment_secret, payee } => {
 				0u8.write(writer)?;
 				let payment_id_opt = Some(payment_id);
 				write_tlv_fields!(writer, {
@@ -5416,6 +5439,7 @@ impl Writeable for HTLCSource {
 					(2, first_hop_htlc_msat, required),
 					(3, payment_secret, option),
 					(4, path, vec_type),
+					(5, payee, option),
 				 });
 			}
 			HTLCSource::PreviousHopData(ref field) => {
@@ -6160,7 +6184,7 @@ mod tests {
 		// Use the utility function send_payment_along_path to send the payment with MPP data which
 		// indicates there are more HTLCs coming.
 		let cur_height = CHAN_CONFIRM_DEPTH + 1; // route_payment calls send_payment, which adds 1 to the current height. So we do the same here to match.
-		nodes[0].node.send_payment_along_path(&route.paths[0], &our_payment_hash, &Some(payment_secret), 200_000, cur_height, payment_id, &None).unwrap();
+		nodes[0].node.send_payment_along_path(&route.paths[0], &route.payee, &our_payment_hash, &Some(payment_secret), 200_000, cur_height, payment_id, &None).unwrap();
 		check_added_monitors!(nodes[0], 1);
 		let mut events = nodes[0].node.get_and_clear_pending_msg_events();
 		assert_eq!(events.len(), 1);
@@ -6190,7 +6214,7 @@ mod tests {
 		expect_payment_failed!(nodes[0], our_payment_hash, true);
 
 		// Send the second half of the original MPP payment.
-		nodes[0].node.send_payment_along_path(&route.paths[0], &our_payment_hash, &Some(payment_secret), 200_000, cur_height, payment_id, &None).unwrap();
+		nodes[0].node.send_payment_along_path(&route.paths[0], &route.payee, &our_payment_hash, &Some(payment_secret), 200_000, cur_height, payment_id, &None).unwrap();
 		check_added_monitors!(nodes[0], 1);
 		let mut events = nodes[0].node.get_and_clear_pending_msg_events();
 		assert_eq!(events.len(), 1);

lightning/src/ln/functional_test_utils.rs

@@ -1114,9 +1114,12 @@ macro_rules! expect_payment_failed_with_update {
 		let events = $node.node.get_and_clear_pending_events();
 		assert_eq!(events.len(), 1);
 		match events[0] {
-			Event::PaymentPathFailed { ref payment_hash, rejected_by_dest, ref network_update, ref error_code, ref error_data, .. } => {
+			Event::PaymentPathFailed { ref payment_hash, rejected_by_dest, ref network_update, ref error_code, ref error_data, ref path, ref retry, .. } => {
 				assert_eq!(*payment_hash, $expected_payment_hash, "unexpected payment_hash");
 				assert_eq!(rejected_by_dest, $rejected_by_dest, "unexpected rejected_by_dest value");
+				assert!(retry.is_some(), "expected retry.is_some()");
+				assert_eq!(retry.as_ref().unwrap().final_value_msat, path.last().unwrap().fee_msat, "Retry amount should match last hop in path");
+				assert_eq!(retry.as_ref().unwrap().payee.pubkey, path.last().unwrap().pubkey, "Retry payee node_id should match last hop in path");
 				assert!(error_code.is_some(), "expected error_code.is_some() = true");
 				assert!(error_data.is_some(), "expected error_data.is_some() = true");
 				match network_update {
@@ -1143,9 +1146,12 @@ macro_rules! expect_payment_failed {
 		let events = $node.node.get_and_clear_pending_events();
 		assert_eq!(events.len(), 1);
 		match events[0] {
-			Event::PaymentPathFailed { ref payment_hash, rejected_by_dest, network_update: _, ref error_code, ref error_data, .. } => {
+			Event::PaymentPathFailed { ref payment_hash, rejected_by_dest, network_update: _, ref error_code, ref error_data, ref path, ref retry, .. } => {
 				assert_eq!(*payment_hash, $expected_payment_hash, "unexpected payment_hash");
 				assert_eq!(rejected_by_dest, $rejected_by_dest, "unexpected rejected_by_dest value");
+				assert!(retry.is_some(), "expected retry.is_some()");
+				assert_eq!(retry.as_ref().unwrap().final_value_msat, path.last().unwrap().fee_msat, "Retry amount should match last hop in path");
+				assert_eq!(retry.as_ref().unwrap().payee.pubkey, path.last().unwrap().pubkey, "Retry payee node_id should match last hop in path");
 				assert!(error_code.is_some(), "expected error_code.is_some() = true");
 				assert!(error_data.is_some(), "expected error_data.is_some() = true");
 				$(

lightning/src/ln/functional_tests.rs

@@ -3912,7 +3912,7 @@ fn do_test_htlc_timeout(send_partial_mpp: bool) {
 		// indicates there are more HTLCs coming.
 		let cur_height = CHAN_CONFIRM_DEPTH + 1; // route_payment calls send_payment, which adds 1 to the current height. So we do the same here to match.
 		let payment_id = PaymentId([42; 32]);
-		nodes[0].node.send_payment_along_path(&route.paths[0], &our_payment_hash, &Some(payment_secret), 200000, cur_height, payment_id, &None).unwrap();
+		nodes[0].node.send_payment_along_path(&route.paths[0], &route.payee, &our_payment_hash, &Some(payment_secret), 200000, cur_height, payment_id, &None).unwrap();
 		check_added_monitors!(nodes[0], 1);
 		let mut events = nodes[0].node.get_and_clear_pending_msg_events();
 		assert_eq!(events.len(), 1);