Reduce default max_channel_saturation_power_of_half to 2 (max 1/4)

Saturating a channel beyond 1/4 of its capacity seems like a more
reasonable threshold for avoiding a path than 1/2, especially given
we should still be willing to send a payment with a lower
saturation limit if it comes to that.

This requires an (obvious) change to some router tests, but also
requires a change to the `fake_network_test`, opting to simply
remove some over-limit test code there - `fake_network_test` was
our first ever functional test, and while it worked great to ensure
LDK worked at all on day one, we now have a rather large breadth
of functional tests, and a broad "does it work at all" test is no
longer all that useful.

diff --git a/lightning/src/ln/functional_tests.rs b/lightning/src/ln/functional_tests.rs
index 4894ed02b3bb5412bb6da0eaf0b01dbfc5af2352..1da45bf2c9916c2455e80f6f2b818c51580468d0 100644 (file)
--- a/lightning/src/ln/functional_tests.rs
+++ b/lightning/src/ln/functional_tests.rs
@@ -1059,26 +1059,6 @@ fn fake_network_test() {
        fail_payment(&nodes[1], &vec!(&nodes[3], &nodes[2], &nodes[1])[..], payment_hash_2);
        claim_payment(&nodes[1], &vec!(&nodes[2], &nodes[3], &nodes[1])[..], payment_preimage_1);
 
-       // Add a duplicate new channel from 2 to 4
-       let chan_5 = create_announced_chan_between_nodes(&nodes, 1, 3, InitFeatures::known(), InitFeatures::known());
-
-       // Send some payments across both channels
-       let payment_preimage_3 = route_payment(&nodes[0], &vec!(&nodes[1], &nodes[3])[..], 3000000).0;
-       let payment_preimage_4 = route_payment(&nodes[0], &vec!(&nodes[1], &nodes[3])[..], 3000000).0;
-       let payment_preimage_5 = route_payment(&nodes[0], &vec!(&nodes[1], &nodes[3])[..], 3000000).0;
-
-
-       route_over_limit(&nodes[0], &vec!(&nodes[1], &nodes[3])[..], 3000000);
-       let events = nodes[0].node.get_and_clear_pending_msg_events();
-       assert_eq!(events.len(), 0);
-       nodes[0].logger.assert_log_regex("lightning::ln::channelmanager".to_string(), regex::Regex::new(r"Cannot send value that would put us over the max HTLC value in flight our peer will accept \(\d+\)").unwrap(), 1);
-
-       //TODO: Test that routes work again here as we've been notified that the channel is full
-
-       claim_payment(&nodes[0], &vec!(&nodes[1], &nodes[3])[..], payment_preimage_3);
-       claim_payment(&nodes[0], &vec!(&nodes[1], &nodes[3])[..], payment_preimage_4);
-       claim_payment(&nodes[0], &vec!(&nodes[1], &nodes[3])[..], payment_preimage_5);
-
        // Close down the channels...
        close_channel(&nodes[0], &nodes[1], &chan_1.2, chan_1.3, true);
        check_closed_event!(nodes[0], 1, ClosureReason::CooperativeClosure);
@@ -1092,9 +1072,6 @@ fn fake_network_test() {
        close_channel(&nodes[1], &nodes[3], &chan_4.2, chan_4.3, false);
        check_closed_event!(nodes[1], 1, ClosureReason::CooperativeClosure);
        check_closed_event!(nodes[3], 1, ClosureReason::CooperativeClosure);
-       close_channel(&nodes[1], &nodes[3], &chan_5.2, chan_5.3, false);
-       check_closed_event!(nodes[1], 1, ClosureReason::CooperativeClosure);
-       check_closed_event!(nodes[3], 1, ClosureReason::CooperativeClosure);
 }
 
 #[test]

diff --git a/lightning/src/routing/router.rs b/lightning/src/routing/router.rs
index 1114f9901837f15d2b4b8d603e95b86190a0ec80..1b14e9c735f145138ed2ad536f6fbf9e8674a9c0 100644 (file)
--- a/lightning/src/routing/router.rs
+++ b/lightning/src/routing/router.rs
@@ -238,7 +238,7 @@ pub struct PaymentParameters {
        /// A value of 0 will allow payments up to and including a channel's total announced usable
        /// capacity, a value of one will only use up to half its capacity, two 1/4, etc.
        ///
-       /// Default value: 1
+       /// Default value: 2
        pub max_channel_saturation_power_of_half: u8,
 
        /// A list of SCIDs which this payment was previously attempted over and which caused the
@@ -253,7 +253,7 @@ impl_writeable_tlv_based!(PaymentParameters, {
        (2, features, option),
        (3, max_path_count, (default_value, DEFAULT_MAX_PATH_COUNT)),
        (4, route_hints, vec_type),
-       (5, max_channel_saturation_power_of_half, (default_value, 1)),
+       (5, max_channel_saturation_power_of_half, (default_value, 2)),
        (6, expiry_time, option),
        (7, previously_failed_channels, vec_type),
 });
@@ -268,7 +268,7 @@ impl PaymentParameters {
                        expiry_time: None,
                        max_total_cltv_expiry_delta: DEFAULT_MAX_TOTAL_CLTV_EXPIRY_DELTA,
                        max_path_count: DEFAULT_MAX_PATH_COUNT,
-                       max_channel_saturation_power_of_half: 1,
+                       max_channel_saturation_power_of_half: 2,
                        previously_failed_channels: Vec::new(),
                }
        }
@@ -4757,7 +4757,7 @@ mod tests {
                                cltv_expiry_delta: 42,
                                htlc_minimum_msat: None,
                                htlc_maximum_msat: None,
-                       }])]);
+                       }])]).with_max_channel_saturation_power_of_half(0);
 
                // Keep only two paths from us to nodes[2], both with a 99sat HTLC maximum, with one with
                // no fee and one with a 1msat fee. Previously, trying to route 100 sats to nodes[2] here
@@ -5741,7 +5741,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: (4 << 4) | 1,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(200_000_000),
+                       htlc_maximum_msat: OptionalField::Present(250_000_000),
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -5753,7 +5753,7 @@ mod tests {
                        flags: 0,
                        cltv_expiry_delta: (13 << 4) | 1,
                        htlc_minimum_msat: 0,
-                       htlc_maximum_msat: OptionalField::Present(200_000_000),
+                       htlc_maximum_msat: OptionalField::Present(250_000_000),
                        fee_base_msat: 0,
                        fee_proportional_millionths: 0,
                        excess_data: Vec::new()
@@ -5762,8 +5762,8 @@ mod tests {
                let payment_params = PaymentParameters::from_node_id(nodes[2]).with_features(InvoiceFeatures::known());
                let keys_manager = test_utils::TestKeysInterface::new(&[0u8; 32], Network::Testnet);
                let random_seed_bytes = keys_manager.get_secure_random_bytes();
-               // 150,000 sat is less than the available liquidity on each channel, set above.
-               let route = get_route(&our_id, &payment_params, &network_graph.read_only(), None, 150_000_000, 42, Arc::clone(&logger), &scorer, &random_seed_bytes).unwrap();
+               // 100,000 sats is less than the available liquidity on each channel, set above.
+               let route = get_route(&our_id, &payment_params, &network_graph.read_only(), None, 100_000_000, 42, Arc::clone(&logger), &scorer, &random_seed_bytes).unwrap();
                assert_eq!(route.paths.len(), 2);
                assert!((route.paths[0][1].short_channel_id == 4 && route.paths[1][1].short_channel_id == 13) ||
                        (route.paths[1][1].short_channel_id == 4 && route.paths[0][1].short_channel_id == 13));