Expire outbound payments after 3 blocks if no parts are pending

Author: valentinewallace

lightning/src/ln/channelmanager.rs

@@ -413,6 +413,8 @@ enum PendingOutboundPayment {
 		pending_amt_msat: u64,
 		/// The total payment amount across all paths, used to verify that a retry is not overpaying.
 		total_msat: u64,
+		/// Our best known block height at the time this payment was initiated.
+		starting_block_height: u32,
 	},
 }
 
@@ -1955,6 +1957,7 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 			pending_amt_msat: 0,
 			payment_hash: *payment_hash,
 			payment_secret: *payment_secret,
+			starting_block_height: self.best_block.read().unwrap().height(),
 			total_msat: total_value,
 		});
 		assert!(payment.insert(session_priv_bytes, path.last().unwrap().fee_msat));
@@ -4546,6 +4549,16 @@ where
 		payment_secrets.retain(|_, inbound_payment| {
 			inbound_payment.expiry_time > header.time as u64
 		});
+
+		let mut outbounds = self.pending_outbound_payments.lock().unwrap();
+		outbounds.retain(|_, payment| {
+			const PAYMENT_EXPIRY_BLOCKS: u32 = 3;
+			if payment.remaining_parts() != 0 { return true }
+			if let PendingOutboundPayment::Retryable { starting_block_height, .. } = payment {
+				return *starting_block_height + PAYMENT_EXPIRY_BLOCKS > height
+			}
+			true
+		});
 	}
 
 	fn get_relevant_txids(&self) -> Vec<Txid> {
@@ -5277,6 +5290,7 @@ impl_writeable_tlv_based_enum!(PendingOutboundPayment,
 		(4, payment_secret, option),
 		(6, total_msat, required),
 		(8, pending_amt_msat, required),
+		(10, starting_block_height, required),
 	},
 ;);
 

lightning/src/ln/functional_tests.rs

@@ -4317,6 +4317,9 @@ fn retry_single_path_payment() {
 	// Rebalance the channel so the retry succeeds.
 	send_payment(&nodes[2], &vec!(&nodes[1])[..], 3_000_000);
 
+	// Mine two blocks (we expire retries after 3, so this will check that we don't expire early)
+	connect_blocks(&nodes[0], 2);
+
 	// Retry the payment and make sure it succeeds.
 	nodes[0].node.retry_payment(&route, payment_id).unwrap();
 	check_added_monitors!(nodes[0], 1);
@@ -4326,6 +4329,58 @@ fn retry_single_path_payment() {
 	claim_payment_along_route(&nodes[0], &[&[&nodes[1], &nodes[2]]], false, payment_preimage);
 }
 
+#[test]
+fn retry_expired_payment() {
+	let chanmon_cfgs = create_chanmon_cfgs(3);
+	let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
+	let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]);
+	let mut nodes = create_network(3, &node_cfgs, &node_chanmgrs);
+
+	let _chan_0 = create_announced_chan_between_nodes(&nodes, 0, 1, InitFeatures::known(), InitFeatures::known());
+	let _chan_1 = create_announced_chan_between_nodes(&nodes, 2, 1, InitFeatures::known(), InitFeatures::known());
+	// Rebalance to find a route
+	send_payment(&nodes[2], &vec!(&nodes[1])[..], 3_000_000);
+
+	let logger = test_utils::TestLogger::new();
+	let (_payment_preimage, payment_hash, payment_secret) = get_payment_preimage_hash!(nodes[2]);
+	let net_graph_msg_handler = &nodes[0].net_graph_msg_handler;
+	let route = get_route(&nodes[0].node.get_our_node_id(), &net_graph_msg_handler.network_graph, &nodes[2].node.get_our_node_id(), Some(InvoiceFeatures::known()), None, &Vec::new(), 100_000, TEST_FINAL_CLTV, &logger).unwrap();
+
+	// Rebalance so that the first hop fails.
+	send_payment(&nodes[1], &vec!(&nodes[2])[..], 2_000_000);
+
+	// Make sure the payment fails on the first hop.
+	let payment_id = nodes[0].node.send_payment(&route, payment_hash, &Some(payment_secret)).unwrap();
+	check_added_monitors!(nodes[0], 1);
+	let mut events = nodes[0].node.get_and_clear_pending_msg_events();
+	assert_eq!(events.len(), 1);
+	let mut payment_event = SendEvent::from_event(events.pop().unwrap());
+	nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &payment_event.msgs[0]);
+	check_added_monitors!(nodes[1], 0);
+	commitment_signed_dance!(nodes[1], nodes[0], payment_event.commitment_msg, false);
+	expect_pending_htlcs_forwardable!(nodes[1]);
+	expect_pending_htlcs_forwardable!(&nodes[1]);
+	let htlc_updates = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
+	assert!(htlc_updates.update_add_htlcs.is_empty());
+	assert_eq!(htlc_updates.update_fail_htlcs.len(), 1);
+	assert!(htlc_updates.update_fulfill_htlcs.is_empty());
+	assert!(htlc_updates.update_fail_malformed_htlcs.is_empty());
+	check_added_monitors!(nodes[1], 1);
+	nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &htlc_updates.update_fail_htlcs[0]);
+	commitment_signed_dance!(nodes[0], nodes[1], htlc_updates.commitment_signed, false);
+	expect_payment_failed!(nodes[0], payment_hash, false);
+
+	// Mine blocks so the payment will have expired.
+	connect_blocks(&nodes[0], 3);
+
+	// Retry the payment and make sure it errors as expected.
+	if let Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError { err })) = nodes[0].node.retry_payment(&route, payment_id) {
+		assert!(err.contains("not found"));
+	} else {
+		panic!("Unexpected error");
+	}
+}
+
 #[test]
 fn test_dup_htlc_onchain_fails_on_reload() {
 	// When a Channel is closed, any outbound HTLCs which were relayed through it are simply