Merge pull request #2818 from valentinewallace/2024-01-blinded-path-retries

Avoid retrying over previously failed blinded paths

Author: TheBlueMatt

lightning/src/ln/blinded_payment_tests.rs

@@ -10,7 +10,7 @@
 use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey};
 use crate::blinded_path::BlindedPath;
 use crate::blinded_path::payment::{ForwardNode, ForwardTlvs, PaymentConstraints, PaymentRelay, ReceiveTlvs};
-use crate::events::{HTLCDestination, MessageSendEvent, MessageSendEventsProvider};
+use crate::events::{Event, HTLCDestination, MessageSendEvent, MessageSendEventsProvider, PaymentFailureReason};
 use crate::ln::PaymentSecret;
 use crate::ln::channelmanager;
 use crate::ln::channelmanager::{PaymentId, RecipientOnionFields};
@@ -21,15 +21,16 @@ use crate::ln::msgs::ChannelMessageHandler;
 use crate::ln::onion_utils;
 use crate::ln::onion_utils::INVALID_ONION_BLINDING;
 use crate::ln::outbound_payment::Retry;
+use crate::offers::invoice::BlindedPayInfo;
 use crate::prelude::*;
 use crate::routing::router::{Payee, PaymentParameters, RouteParameters};
 use crate::util::config::UserConfig;
 use crate::util::test_utils;
 
-pub fn get_blinded_route_parameters(
-	amt_msat: u64, payment_secret: PaymentSecret, node_ids: Vec<PublicKey>,
+fn blinded_payment_path(
+	payment_secret: PaymentSecret, node_ids: Vec<PublicKey>,
 	channel_upds: &[&msgs::UnsignedChannelUpdate], keys_manager: &test_utils::TestKeysInterface
-) -> RouteParameters {
+) -> (BlindedPayInfo, BlindedPath) {
 	let mut intermediate_nodes = Vec::new();
 	for (node_id, chan_upd) in node_ids.iter().zip(channel_upds) {
 		intermediate_nodes.push(ForwardNode {
@@ -58,13 +59,20 @@ pub fn get_blinded_route_parameters(
 		},
 	};
 	let mut secp_ctx = Secp256k1::new();
-	let blinded_path = BlindedPath::new_for_payment(
+	BlindedPath::new_for_payment(
 		&intermediate_nodes[..], *node_ids.last().unwrap(), payee_tlvs,
 		channel_upds.last().unwrap().htlc_maximum_msat, keys_manager, &secp_ctx
-	).unwrap();
+	).unwrap()
+}
 
+pub fn get_blinded_route_parameters(
+	amt_msat: u64, payment_secret: PaymentSecret, node_ids: Vec<PublicKey>,
+	channel_upds: &[&msgs::UnsignedChannelUpdate], keys_manager: &test_utils::TestKeysInterface
+) -> RouteParameters {
 	RouteParameters::from_payment_params_and_value(
-		PaymentParameters::blinded(vec![blinded_path]), amt_msat
+		PaymentParameters::blinded(vec![
+			blinded_payment_path(payment_secret, node_ids, channel_upds, keys_manager)
+		]), amt_msat
 	)
 }
 
@@ -725,3 +733,108 @@ fn do_multi_hop_receiver_fail(check: ReceiveCheckFail) {
 	expect_payment_failed_conditions(&nodes[0], payment_hash, false,
 		PaymentFailedConditions::new().expected_htlc_error_data(INVALID_ONION_BLINDING, &[0; 32]));
 }
+
+#[test]
+fn blinded_path_retries() {
+	let chanmon_cfgs = create_chanmon_cfgs(4);
+	// Make one blinded path's fees slightly higher so they are tried in a deterministic order.
+	let mut higher_fee_chan_cfg = test_default_channel_config();
+	higher_fee_chan_cfg.channel_config.forwarding_fee_base_msat += 1;
+	let node_cfgs = create_node_cfgs(4, &chanmon_cfgs);
+	let node_chanmgrs = create_node_chanmgrs(4, &node_cfgs, &[None, None, Some(higher_fee_chan_cfg), None]);
+	let mut nodes = create_network(4, &node_cfgs, &node_chanmgrs);
+
+	// Create this network topology so nodes[0] has a blinded route hint to retry over.
+	//      n1
+	//    /    \
+	// n0       n3
+	//    \    /
+	//      n2
+	create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0);
+	create_announced_chan_between_nodes_with_value(&nodes, 0, 2, 1_000_000, 0);
+	let chan_1_3 = create_announced_chan_between_nodes_with_value(&nodes, 1, 3, 1_000_000, 0);
+	let chan_2_3 = create_announced_chan_between_nodes_with_value(&nodes, 2, 3, 1_000_000, 0);
+
+	let amt_msat = 5000;
+	let (_, payment_hash, payment_secret) = get_payment_preimage_hash(&nodes[3], Some(amt_msat), None);
+	let route_params = {
+		let pay_params = PaymentParameters::blinded(
+			vec![
+				blinded_payment_path(payment_secret,
+					vec![nodes[1].node.get_our_node_id(), nodes[3].node.get_our_node_id()], &[&chan_1_3.0.contents],
+					&chanmon_cfgs[3].keys_manager
+				),
+				blinded_payment_path(payment_secret,
+					vec![nodes[2].node.get_our_node_id(), nodes[3].node.get_our_node_id()], &[&chan_2_3.0.contents],
+					&chanmon_cfgs[3].keys_manager
+				),
+			]
+		)
+			.with_bolt12_features(channelmanager::provided_bolt12_invoice_features(&UserConfig::default()))
+			.unwrap();
+		RouteParameters::from_payment_params_and_value(pay_params, amt_msat)
+	};
+
+	nodes[0].node.send_payment(payment_hash, RecipientOnionFields::spontaneous_empty(), PaymentId(payment_hash.0), route_params.clone(), Retry::Attempts(2)).unwrap();
+	check_added_monitors(&nodes[0], 1);
+	pass_along_route(&nodes[0], &[&[&nodes[1], &nodes[3]]], amt_msat, payment_hash, payment_secret);
+
+	macro_rules! fail_payment_back {
+		($intro_node: expr) => {
+			nodes[3].node.fail_htlc_backwards(&payment_hash);
+			expect_pending_htlcs_forwardable_conditions(
+				nodes[3].node.get_and_clear_pending_events(), &[HTLCDestination::FailedPayment { payment_hash }]
+			);
+			nodes[3].node.process_pending_htlc_forwards();
+			check_added_monitors!(nodes[3], 1);
+
+			let updates = get_htlc_update_msgs!(nodes[3], $intro_node.node.get_our_node_id());
+			assert_eq!(updates.update_fail_malformed_htlcs.len(), 1);
+			let update_malformed = &updates.update_fail_malformed_htlcs[0];
+			assert_eq!(update_malformed.sha256_of_onion, [0; 32]);
+			assert_eq!(update_malformed.failure_code, INVALID_ONION_BLINDING);
+			$intro_node.node.handle_update_fail_malformed_htlc(&nodes[3].node.get_our_node_id(), update_malformed);
+			do_commitment_signed_dance(&$intro_node, &nodes[3], &updates.commitment_signed, true, false);
+
+			let updates =  get_htlc_update_msgs!($intro_node, nodes[0].node.get_our_node_id());
+			assert_eq!(updates.update_fail_htlcs.len(), 1);
+			nodes[0].node.handle_update_fail_htlc(&$intro_node.node.get_our_node_id(), &updates.update_fail_htlcs[0]);
+			do_commitment_signed_dance(&nodes[0], &$intro_node, &updates.commitment_signed, false, false);
+
+			let mut events = nodes[0].node.get_and_clear_pending_events();
+			assert_eq!(events.len(), 2);
+			match events[0] {
+				Event::PaymentPathFailed { payment_hash: ev_payment_hash, payment_failed_permanently, ..  } => {
+					assert_eq!(payment_hash, ev_payment_hash);
+					assert_eq!(payment_failed_permanently, false);
+				},
+				_ => panic!("Unexpected event"),
+			}
+			match events[1] {
+				Event::PendingHTLCsForwardable { .. } => {},
+				_ => panic!("Unexpected event"),
+			}
+			nodes[0].node.process_pending_htlc_forwards();
+		}
+	}
+
+	fail_payment_back!(nodes[1]);
+
+	// Pass the retry along.
+	check_added_monitors!(nodes[0], 1);
+	let mut msg_events = nodes[0].node.get_and_clear_pending_msg_events();
+	assert_eq!(msg_events.len(), 1);
+	pass_along_path(&nodes[0], &[&nodes[2], &nodes[3]], amt_msat, payment_hash, Some(payment_secret), msg_events.pop().unwrap(), true, None);
+
+	fail_payment_back!(nodes[2]);
+	let evs = nodes[0].node.get_and_clear_pending_events();
+	assert_eq!(evs.len(), 1);
+	match evs[0] {
+		Event::PaymentFailed { payment_hash: ev_payment_hash, reason, .. } => {
+			assert_eq!(ev_payment_hash, payment_hash);
+			// We have 1 retry attempt remaining, but we're out of blinded paths to try.
+			assert_eq!(reason, Some(PaymentFailureReason::RouteNotFound));
+		},
+		_ => panic!()
+	}
+}

lightning/src/ln/onion_utils.rs

@@ -429,6 +429,7 @@ pub(crate) struct DecodedOnionFailure {
 	pub(crate) network_update: Option<NetworkUpdate>,
 	pub(crate) short_channel_id: Option<u64>,
 	pub(crate) payment_failed_permanently: bool,
+	pub(crate) failed_within_blinded_path: bool,
 	#[cfg(test)]
 	pub(crate) onion_error_code: Option<u16>,
 	#[cfg(test)]
@@ -463,6 +464,7 @@ pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
 		network_update: Option<NetworkUpdate>,
 		short_channel_id: Option<u64>,
 		payment_failed_permanently: bool,
+		failed_within_blinded_path: bool,
 	}
 	let mut res: Option<FailureLearnings> = None;
 	let mut htlc_msat = *first_hop_htlc_msat;
@@ -488,7 +490,8 @@ pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
 				error_code_ret = Some(BADONION | PERM | 24); // invalid_onion_blinding
 				error_packet_ret = Some(vec![0; 32]);
 				res = Some(FailureLearnings {
-					network_update: None, short_channel_id: None, payment_failed_permanently: false
+					network_update: None, short_channel_id: None, payment_failed_permanently: false,
+					failed_within_blinded_path: true,
 				});
 				return
 			},
@@ -520,7 +523,8 @@ pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
 					}
 
 					res = Some(FailureLearnings {
-						network_update: None, short_channel_id: None, payment_failed_permanently: false
+						network_update: None, short_channel_id: None, payment_failed_permanently: false,
+						failed_within_blinded_path: true,
 					});
 					return
 				}
@@ -550,7 +554,8 @@ pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
 				});
 				let short_channel_id = Some(route_hop.short_channel_id);
 				res = Some(FailureLearnings {
-					network_update, short_channel_id, payment_failed_permanently: is_from_final_node
+					network_update, short_channel_id, payment_failed_permanently: is_from_final_node,
+					failed_within_blinded_path: false
 				});
 				return
 			}
@@ -706,7 +711,8 @@ pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
 
 		res = Some(FailureLearnings {
 			network_update, short_channel_id,
-			payment_failed_permanently: error_code & PERM == PERM && is_from_final_node
+			payment_failed_permanently: error_code & PERM == PERM && is_from_final_node,
+			failed_within_blinded_path: false
 		});
 
 		let (description, title) = errors::get_onion_error_description(error_code);
@@ -717,10 +723,10 @@ pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
 		}
 	}).expect("Route that we sent via spontaneously grew invalid keys in the middle of it?");
 	if let Some(FailureLearnings {
-		network_update, short_channel_id, payment_failed_permanently
+		network_update, short_channel_id, payment_failed_permanently, failed_within_blinded_path
 	}) = res {
 		DecodedOnionFailure {
-			network_update, short_channel_id, payment_failed_permanently,
+			network_update, short_channel_id, payment_failed_permanently, failed_within_blinded_path,
 			#[cfg(test)]
 			onion_error_code: error_code_ret,
 			#[cfg(test)]
@@ -731,6 +737,7 @@ pub(super) fn process_onion_failure<T: secp256k1::Signing, L: Deref>(
 		// payment not retryable only when garbage is from the final node
 		DecodedOnionFailure {
 			network_update: None, short_channel_id: None, payment_failed_permanently: is_from_final_node,
+			failed_within_blinded_path: false,
 			#[cfg(test)]
 			onion_error_code: None,
 			#[cfg(test)]
@@ -878,6 +885,7 @@ impl HTLCFailReason {
 						network_update: None,
 						payment_failed_permanently: false,
 						short_channel_id: Some(path.hops[0].short_channel_id),
+						failed_within_blinded_path: false,
 						#[cfg(test)]
 						onion_error_code: Some(*failure_code),
 						#[cfg(test)]

lightning/src/ln/outbound_payment.rs

@@ -19,7 +19,7 @@ use crate::ln::{PaymentHash, PaymentPreimage, PaymentSecret};
 use crate::ln::channelmanager::{ChannelDetails, EventCompletionAction, HTLCSource, PaymentId};
 use crate::ln::onion_utils::{DecodedOnionFailure, HTLCFailReason};
 use crate::offers::invoice::Bolt12Invoice;
-use crate::routing::router::{InFlightHtlcs, Path, PaymentParameters, Route, RouteParameters, Router};
+use crate::routing::router::{BlindedTail, InFlightHtlcs, Path, PaymentParameters, Route, RouteParameters, Router};
 use crate::util::errors::APIError;
 use crate::util::logger::Logger;
 use crate::util::time::Time;
@@ -129,6 +129,11 @@ impl PendingOutboundPayment {
 			params.previously_failed_channels.push(scid);
 		}
 	}
+	pub fn insert_previously_failed_blinded_path(&mut self, blinded_tail: &BlindedTail) {
+		if let PendingOutboundPayment::Retryable { payment_params: Some(params), .. } = self {
+			params.insert_previously_failed_blinded_path(blinded_tail);
+		}
+	}
 	fn is_awaiting_invoice(&self) -> bool {
 		match self {
 			PendingOutboundPayment::AwaitingInvoice { .. } => true,
@@ -1604,11 +1609,12 @@ impl OutboundPayments {
 		#[cfg(test)]
 		let DecodedOnionFailure {
 			network_update, short_channel_id, payment_failed_permanently, onion_error_code,
-			onion_error_data
+			onion_error_data, failed_within_blinded_path
 		} = onion_error.decode_onion_failure(secp_ctx, logger, &source);
 		#[cfg(not(test))]
-		let DecodedOnionFailure { network_update, short_channel_id, payment_failed_permanently } =
-			onion_error.decode_onion_failure(secp_ctx, logger, &source);
+		let DecodedOnionFailure {
+			network_update, short_channel_id, payment_failed_permanently, failed_within_blinded_path
+		} = onion_error.decode_onion_failure(secp_ctx, logger, &source);
 
 		let payment_is_probe = payment_is_probe(payment_hash, &payment_id, probing_cookie_secret);
 		let mut session_priv_bytes = [0; 32];
@@ -1647,6 +1653,12 @@ impl OutboundPayments {
 				// next-hop is needlessly blaming us!
 				payment.get_mut().insert_previously_failed_scid(scid);
 			}
+			if failed_within_blinded_path {
+				debug_assert!(short_channel_id.is_none());
+				if let Some(bt) = &path.blinded_tail {
+					payment.get_mut().insert_previously_failed_blinded_path(&bt);
+				} else { debug_assert!(false); }
+			}
 
 			if payment_is_probe || !is_retryable_now || payment_failed_permanently {
 				let reason = if payment_failed_permanently {