+#[test]
+fn test_onion_value_mpp_set_calculation() {
+ // Test that we use the onion value `amt_to_forward` when
+ // calculating whether we've reached the `total_msat` of an MPP
+ // by having a routing node forward more than `amt_to_forward`
+ // and checking that the receiving node doesn't generate
+ // a PaymentClaimable event too early
+ let node_count = 4;
+ let chanmon_cfgs = create_chanmon_cfgs(node_count);
+ let node_cfgs = create_node_cfgs(node_count, &chanmon_cfgs);
+ let node_chanmgrs = create_node_chanmgrs(node_count, &node_cfgs, &vec![None; node_count]);
+ let mut nodes = create_network(node_count, &node_cfgs, &node_chanmgrs);
+
+ let chan_1_id = create_announced_chan_between_nodes(&nodes, 0, 1).0.contents.short_channel_id;
+ let chan_2_id = create_announced_chan_between_nodes(&nodes, 0, 2).0.contents.short_channel_id;
+ let chan_3_id = create_announced_chan_between_nodes(&nodes, 1, 3).0.contents.short_channel_id;
+ let chan_4_id = create_announced_chan_between_nodes(&nodes, 2, 3).0.contents.short_channel_id;
+
+ let total_msat = 100_000;
+ let expected_paths: &[&[&Node]] = &[&[&nodes[1], &nodes[3]], &[&nodes[2], &nodes[3]]];
+ let (mut route, our_payment_hash, our_payment_preimage, our_payment_secret) = get_route_and_payment_hash!(&nodes[0], nodes[3], total_msat);
+ let sample_path = route.paths.pop().unwrap();
+
+ let mut path_1 = sample_path.clone();
+ path_1.hops[0].pubkey = nodes[1].node.get_our_node_id();
+ path_1.hops[0].short_channel_id = chan_1_id;
+ path_1.hops[1].pubkey = nodes[3].node.get_our_node_id();
+ path_1.hops[1].short_channel_id = chan_3_id;
+ path_1.hops[1].fee_msat = 100_000;
+ route.paths.push(path_1);
+
+ let mut path_2 = sample_path.clone();
+ path_2.hops[0].pubkey = nodes[2].node.get_our_node_id();
+ path_2.hops[0].short_channel_id = chan_2_id;
+ path_2.hops[1].pubkey = nodes[3].node.get_our_node_id();
+ path_2.hops[1].short_channel_id = chan_4_id;
+ path_2.hops[1].fee_msat = 1_000;
+ route.paths.push(path_2);
+
+ // Send payment
+ let payment_id = PaymentId(nodes[0].keys_manager.backing.get_secure_random_bytes());
+ let onion_session_privs = nodes[0].node.test_add_new_pending_payment(our_payment_hash,
+ RecipientOnionFields::secret_only(our_payment_secret), payment_id, &route).unwrap();
+ nodes[0].node.test_send_payment_internal(&route, our_payment_hash,
+ RecipientOnionFields::secret_only(our_payment_secret), None, payment_id, Some(total_msat), onion_session_privs).unwrap();
+ check_added_monitors!(nodes[0], expected_paths.len());
+
+ let mut events = nodes[0].node.get_and_clear_pending_msg_events();
+ assert_eq!(events.len(), expected_paths.len());
+
+ // First path
+ let ev = remove_first_msg_event_to_node(&expected_paths[0][0].node.get_our_node_id(), &mut events);
+ let mut payment_event = SendEvent::from_event(ev);
+ let mut prev_node = &nodes[0];
+
+ for (idx, &node) in expected_paths[0].iter().enumerate() {
+ assert_eq!(node.node.get_our_node_id(), payment_event.node_id);
+
+ if idx == 0 { // routing node
+ let session_priv = [3; 32];
+ let height = nodes[0].best_block_info().1;
+ let session_priv = SecretKey::from_slice(&session_priv).unwrap();
+ let mut onion_keys = onion_utils::construct_onion_keys(&Secp256k1::new(), &route.paths[0], &session_priv).unwrap();
+ let (mut onion_payloads, _, _) = onion_utils::build_onion_payloads(&route.paths[0], 100_000,
+ 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;
+ let new_onion_packet = onion_utils::construct_onion_packet(onion_payloads, onion_keys, [0; 32], &our_payment_hash);
+ payment_event.msgs[0].onion_routing_packet = new_onion_packet;
+ }
+
+ node.node.handle_update_add_htlc(&prev_node.node.get_our_node_id(), &payment_event.msgs[0]);
+ check_added_monitors!(node, 0);
+ commitment_signed_dance!(node, prev_node, payment_event.commitment_msg, false);
+ expect_pending_htlcs_forwardable!(node);
+
+ if idx == 0 {
+ let mut events_2 = node.node.get_and_clear_pending_msg_events();
+ assert_eq!(events_2.len(), 1);
+ check_added_monitors!(node, 1);
+ payment_event = SendEvent::from_event(events_2.remove(0));
+ assert_eq!(payment_event.msgs.len(), 1);
+ } else {
+ let events_2 = node.node.get_and_clear_pending_events();
+ assert!(events_2.is_empty());
+ }
+
+ prev_node = node;
+ }
+
+ // Second path
+ let ev = remove_first_msg_event_to_node(&expected_paths[1][0].node.get_our_node_id(), &mut events);
+ pass_along_path(&nodes[0], expected_paths[1], 101_000, our_payment_hash.clone(), Some(our_payment_secret), ev, true, None);
+
+ claim_payment_along_route(&nodes[0], expected_paths, false, our_payment_preimage);
+}
+
+fn do_test_overshoot_mpp(msat_amounts: &[u64], total_msat: u64) {
+
+ let routing_node_count = msat_amounts.len();
+ let node_count = routing_node_count + 2;
+
+ let chanmon_cfgs = create_chanmon_cfgs(node_count);
+ let node_cfgs = create_node_cfgs(node_count, &chanmon_cfgs);
+ let node_chanmgrs = create_node_chanmgrs(node_count, &node_cfgs, &vec![None; node_count]);
+ let nodes = create_network(node_count, &node_cfgs, &node_chanmgrs);
+
+ let src_idx = 0;
+ let dst_idx = 1;
+
+ // Create channels for each amount
+ let mut expected_paths = Vec::with_capacity(routing_node_count);
+ let mut src_chan_ids = Vec::with_capacity(routing_node_count);
+ let mut dst_chan_ids = Vec::with_capacity(routing_node_count);
+ for i in 0..routing_node_count {
+ let routing_node = 2 + i;
+ let src_chan_id = create_announced_chan_between_nodes(&nodes, src_idx, routing_node).0.contents.short_channel_id;
+ src_chan_ids.push(src_chan_id);
+ let dst_chan_id = create_announced_chan_between_nodes(&nodes, routing_node, dst_idx).0.contents.short_channel_id;
+ dst_chan_ids.push(dst_chan_id);
+ let path = vec![&nodes[routing_node], &nodes[dst_idx]];
+ expected_paths.push(path);
+ }
+ let expected_paths: Vec<&[&Node]> = expected_paths.iter().map(|route| route.as_slice()).collect();
+
+ // Create a route for each amount
+ let example_amount = 100000;
+ let (mut route, our_payment_hash, our_payment_preimage, our_payment_secret) = get_route_and_payment_hash!(&nodes[src_idx], nodes[dst_idx], example_amount);
+ let sample_path = route.paths.pop().unwrap();
+ for i in 0..routing_node_count {
+ let routing_node = 2 + i;
+ let mut path = sample_path.clone();
+ path.hops[0].pubkey = nodes[routing_node].node.get_our_node_id();
+ path.hops[0].short_channel_id = src_chan_ids[i];
+ path.hops[1].pubkey = nodes[dst_idx].node.get_our_node_id();
+ path.hops[1].short_channel_id = dst_chan_ids[i];
+ path.hops[1].fee_msat = msat_amounts[i];
+ route.paths.push(path);
+ }
+
+ // Send payment with manually set total_msat
+ let payment_id = PaymentId(nodes[src_idx].keys_manager.backing.get_secure_random_bytes());
+ let onion_session_privs = nodes[src_idx].node.test_add_new_pending_payment(our_payment_hash,
+ RecipientOnionFields::secret_only(our_payment_secret), payment_id, &route).unwrap();
+ nodes[src_idx].node.test_send_payment_internal(&route, our_payment_hash,
+ RecipientOnionFields::secret_only(our_payment_secret), None, payment_id, Some(total_msat), onion_session_privs).unwrap();
+ check_added_monitors!(nodes[src_idx], expected_paths.len());
+
+ let mut events = nodes[src_idx].node.get_and_clear_pending_msg_events();
+ assert_eq!(events.len(), expected_paths.len());
+ let mut amount_received = 0;
+ for (path_idx, expected_path) in expected_paths.iter().enumerate() {
+ let ev = remove_first_msg_event_to_node(&expected_path[0].node.get_our_node_id(), &mut events);
+
+ let current_path_amount = msat_amounts[path_idx];
+ amount_received += current_path_amount;
+ let became_claimable_now = amount_received >= total_msat && amount_received - current_path_amount < total_msat;
+ pass_along_path(&nodes[src_idx], expected_path, amount_received, our_payment_hash.clone(), Some(our_payment_secret), ev, became_claimable_now, None);
+ }
+
+ claim_payment_along_route(&nodes[src_idx], &expected_paths, false, our_payment_preimage);
+}
+
+#[test]
+fn test_overshoot_mpp() {
+ do_test_overshoot_mpp(&[100_000, 101_000], 200_000);
+ do_test_overshoot_mpp(&[100_000, 10_000, 100_000], 200_000);
+}
+