+
+#[test]
+fn test_htlc_forward_considers_anchor_outputs_value() {
+ // Tests that:
+ //
+ // 1) Forwarding nodes don't forward HTLCs that would cause their balance to dip below the
+ // reserve when considering the value of anchor outputs.
+ //
+ // 2) Recipients of `update_add_htlc` properly reject HTLCs that would cause the initiator's
+ // balance to dip below the reserve when considering the value of anchor outputs.
+ let mut config = test_default_channel_config();
+ config.channel_handshake_config.negotiate_anchors_zero_fee_htlc_tx = true;
+ config.manually_accept_inbound_channels = true;
+ config.channel_config.forwarding_fee_base_msat = 0;
+ config.channel_config.forwarding_fee_proportional_millionths = 0;
+
+ // Set up a test network of three nodes that replicates a production failure leading to the
+ // discovery of this bug.
+ 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, &[Some(config), Some(config), Some(config)]);
+ let nodes = create_network(3, &node_cfgs, &node_chanmgrs);
+
+ const CHAN_AMT: u64 = 1_000_000;
+ const PUSH_MSAT: u64 = 900_000_000;
+ create_announced_chan_between_nodes_with_value(&nodes, 0, 1, CHAN_AMT, 500_000_000);
+ let (_, _, chan_id_2, _) = create_announced_chan_between_nodes_with_value(&nodes, 1, 2, CHAN_AMT, PUSH_MSAT);
+
+ let channel_reserve_msat = get_holder_selected_channel_reserve_satoshis(CHAN_AMT, &config) * 1000;
+ let commitment_fee_msat = commit_tx_fee_msat(
+ *nodes[1].fee_estimator.sat_per_kw.lock().unwrap(), 2, &ChannelTypeFeatures::anchors_zero_htlc_fee_and_dependencies()
+ );
+ let anchor_outpus_value_msat = ANCHOR_OUTPUT_VALUE_SATOSHI * 2 * 1000;
+ let sendable_balance_msat = CHAN_AMT * 1000 - PUSH_MSAT - channel_reserve_msat - commitment_fee_msat - anchor_outpus_value_msat;
+ let channel_details = nodes[1].node.list_channels().into_iter().find(|channel| channel.channel_id == chan_id_2).unwrap();
+ assert!(sendable_balance_msat >= channel_details.next_outbound_htlc_minimum_msat);
+ assert!(sendable_balance_msat <= channel_details.next_outbound_htlc_limit_msat);
+
+ send_payment(&nodes[0], &[&nodes[1], &nodes[2]], sendable_balance_msat);
+ send_payment(&nodes[2], &[&nodes[1], &nodes[0]], sendable_balance_msat);
+
+ // Send out an HTLC that would cause the forwarding node to dip below its reserve when
+ // considering the value of anchor outputs.
+ let (route, payment_hash, _, payment_secret) = get_route_and_payment_hash!(
+ nodes[0], nodes[2], sendable_balance_msat + anchor_outpus_value_msat
+ );
+ nodes[0].node.send_payment_with_route(
+ &route, payment_hash, RecipientOnionFields::secret_only(payment_secret), PaymentId(payment_hash.0)
+ ).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 update_add_htlc = if let MessageSendEvent::UpdateHTLCs { updates, .. } = events.pop().unwrap() {
+ nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &updates.update_add_htlcs[0]);
+ check_added_monitors(&nodes[1], 0);
+ commitment_signed_dance!(nodes[1], nodes[0], &updates.commitment_signed, false);
+ updates.update_add_htlcs[0].clone()
+ } else {
+ panic!("Unexpected event");
+ };
+
+ // The forwarding node should reject forwarding it as expected.
+ expect_pending_htlcs_forwardable!(nodes[1]);
+ expect_pending_htlcs_forwardable_and_htlc_handling_failed!(&nodes[1], vec![HTLCDestination::NextHopChannel {
+ node_id: Some(nodes[2].node.get_our_node_id()),
+ channel_id: chan_id_2
+ }]);
+ check_added_monitors(&nodes[1], 1);
+
+ let mut events = nodes[1].node.get_and_clear_pending_msg_events();
+ assert_eq!(events.len(), 1);
+ if let MessageSendEvent::UpdateHTLCs { updates, .. } = events.pop().unwrap() {
+ nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &updates.update_fail_htlcs[0]);
+ check_added_monitors(&nodes[0], 0);
+ commitment_signed_dance!(nodes[0], nodes[1], &updates.commitment_signed, false);
+ } else {
+ panic!("Unexpected event");
+ }
+
+ expect_payment_failed!(nodes[0], payment_hash, false);
+
+ // Assume that the forwarding node did forward it, and make sure the recipient rejects it as an
+ // invalid update and closes the channel.
+ update_add_htlc.channel_id = chan_id_2;
+ nodes[2].node.handle_update_add_htlc(&nodes[1].node.get_our_node_id(), &update_add_htlc);
+ check_closed_event(&nodes[2], 1, ClosureReason::ProcessingError {
+ err: "Remote HTLC add would put them under remote reserve value".to_owned()
+ }, false, &[nodes[1].node.get_our_node_id()], 1_000_000);
+ check_closed_broadcast(&nodes[2], 1, true);
+ check_added_monitors(&nodes[2], 1);
+}
+
+#[test]
+fn peel_payment_onion_custom_tlvs() {
+ let chanmon_cfgs = create_chanmon_cfgs(2);
+ let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
+ let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
+ let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
+ create_announced_chan_between_nodes(&nodes, 0, 1);
+ let secp_ctx = Secp256k1::new();
+
+ let amt_msat = 1000;
+ let payment_params = PaymentParameters::for_keysend(nodes[1].node.get_our_node_id(),
+ TEST_FINAL_CLTV, false);
+ let route_params = RouteParameters::from_payment_params_and_value(payment_params, amt_msat);
+ let route = functional_test_utils::get_route(&nodes[0], &route_params).unwrap();
+ let mut recipient_onion = RecipientOnionFields::spontaneous_empty()
+ .with_custom_tlvs(vec![(414141, vec![42; 1200])]).unwrap();
+ let prng_seed = chanmon_cfgs[0].keys_manager.get_secure_random_bytes();
+ let session_priv = SecretKey::from_slice(&prng_seed[..]).expect("RNG is busted");
+ let keysend_preimage = PaymentPreimage([42; 32]);
+ let payment_hash = PaymentHash(Sha256::hash(&keysend_preimage.0).to_byte_array());
+
+ let (onion_routing_packet, first_hop_msat, cltv_expiry) = onion_utils::create_payment_onion(
+ &secp_ctx, &route.paths[0], &session_priv, amt_msat, recipient_onion.clone(),
+ nodes[0].best_block_info().1, &payment_hash, &Some(keysend_preimage), prng_seed
+ ).unwrap();
+
+ let update_add = msgs::UpdateAddHTLC {
+ channel_id: ChannelId([0; 32]),
+ htlc_id: 42,
+ amount_msat: first_hop_msat,
+ payment_hash,
+ cltv_expiry,
+ skimmed_fee_msat: None,
+ onion_routing_packet,
+ blinding_point: None,
+ };
+ let peeled_onion = crate::ln::onion_payment::peel_payment_onion(
+ &update_add, &&chanmon_cfgs[1].keys_manager, &&chanmon_cfgs[1].logger, &secp_ctx,
+ nodes[1].best_block_info().1, true, false
+ ).unwrap();
+ assert_eq!(peeled_onion.incoming_amt_msat, Some(amt_msat));
+ match peeled_onion.routing {
+ PendingHTLCRouting::ReceiveKeysend {
+ payment_data, payment_metadata, custom_tlvs, ..
+ } => {
+ #[cfg(not(c_bindings))]
+ assert_eq!(&custom_tlvs, recipient_onion.custom_tlvs());
+ #[cfg(c_bindings)]
+ assert_eq!(custom_tlvs, recipient_onion.custom_tlvs());
+ assert!(payment_metadata.is_none());
+ assert!(payment_data.is_none());
+ },
+ _ => panic!()
+ }
+}