X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning-invoice%2Fsrc%2Futils.rs;h=38f3a597871a8327e9dd33c0c912f5c70688d843;hb=5b8af341e84bac7d7eb2344b12d4c43918922804;hp=06f11a91e240ae33207c9b4aa4e39ccac4183c41;hpb=14ee173593e6ee5501e10767ffa6ce1533a9bb2e;p=rust-lightning diff --git a/lightning-invoice/src/utils.rs b/lightning-invoice/src/utils.rs index 06f11a91..38f3a597 100644 --- a/lightning-invoice/src/utils.rs +++ b/lightning-invoice/src/utils.rs @@ -509,7 +509,11 @@ fn _create_invoice_from_channelmanager_and_duration_since_epoch_with_payment_has /// /// The filtering is based on the following criteria: /// * Only one channel per counterparty node -/// * Always select the channel with the highest inbound capacity per counterparty node +/// * If the counterparty has a channel that is above the `min_inbound_capacity_msat` + 10% scaling +/// factor (to allow some margin for change in inbound), select the channel with the lowest +/// inbound capacity that is above this threshold. +/// * If no `min_inbound_capacity_msat` is specified, or the counterparty has no channels above the +/// minimum + 10% scaling factor, select the channel with the highest inbound capacity per counterparty. /// * Prefer channels with capacity at least `min_inbound_capacity_msat` and where the channel /// `is_usable` (i.e. the peer is connected). /// * If any public channel exists, only public [`RouteHint`]s will be returned. @@ -570,12 +574,16 @@ fn filter_channels( // If this channel is public and the previous channel is not, ensure we replace the // previous channel to avoid announcing non-public channels. let new_now_public = channel.is_public && !entry.get().is_public; + // Decide whether we prefer the currently selected channel with the node to the new one, + // based on their inbound capacity. + let prefer_current = prefer_current_channel(min_inbound_capacity_msat, current_max_capacity, + channel.inbound_capacity_msat); // If the public-ness of the channel has not changed (in which case simply defer to - // `new_now_public), and this channel has a greater capacity, prefer to announce - // this channel. - let new_higher_capacity = channel.is_public == entry.get().is_public && - channel.inbound_capacity_msat > current_max_capacity; - if new_now_public || new_higher_capacity { + // `new_now_public), and this channel has more desirable inbound than the incumbent, + // prefer to include this channel. + let new_channel_preferable = channel.is_public == entry.get().is_public && !prefer_current; + + if new_now_public || new_channel_preferable { log_trace!(logger, "Preferring counterparty {} channel {} (SCID {:?}, {} msats) over {} (SCID {:?}, {} msats) for invoice route hints", log_pubkey!(channel.counterparty.node_id), @@ -658,6 +666,41 @@ fn filter_channels( .collect::>() } +/// prefer_current_channel chooses a channel to use for route hints between a currently selected and candidate +/// channel based on the inbound capacity of each channel and the minimum inbound capacity requested for the hints, +/// returning true if the current channel should be preferred over the candidate channel. +/// * If no minimum amount is requested, the channel with the most inbound is chosen to maximize the chances that a +/// payment of any size will succeed. +/// * If we have channels with inbound above our minimum requested inbound (plus a 10% scaling factor, expressed as a +/// percentage) then we choose the lowest inbound channel with above this amount. If we have sufficient inbound +/// channels, we don't want to deplete our larger channels with small payments (the off-chain version of "grinding +/// our change"). +/// * If no channel above our minimum amount exists, then we just prefer the channel with the most inbound to give +/// payments the best chance of succeeding in multiple parts. +fn prefer_current_channel(min_inbound_capacity_msat: Option, current_channel: u64, + candidate_channel: u64) -> bool { + + // If no min amount is given for the hints, err of the side of caution and choose the largest channel inbound to + // maximize chances of any payment succeeding. + if min_inbound_capacity_msat.is_none() { + return current_channel > candidate_channel + } + + let scaled_min_inbound = min_inbound_capacity_msat.unwrap() * 110; + let current_sufficient = current_channel * 100 >= scaled_min_inbound; + let candidate_sufficient = candidate_channel * 100 >= scaled_min_inbound; + + if current_sufficient && candidate_sufficient { + return current_channel < candidate_channel + } else if current_sufficient { + return true + } else if candidate_sufficient { + return false + } + + current_channel > candidate_channel +} + #[cfg(test)] mod test { use core::time::Duration; @@ -665,17 +708,45 @@ mod test { use bitcoin_hashes::{Hash, sha256}; use bitcoin_hashes::sha256::Hash as Sha256; use lightning::chain::keysinterface::{EntropySource, PhantomKeysManager}; + use lightning::events::{MessageSendEvent, MessageSendEventsProvider, Event}; use lightning::ln::{PaymentPreimage, PaymentHash}; use lightning::ln::channelmanager::{PhantomRouteHints, MIN_FINAL_CLTV_EXPIRY_DELTA, PaymentId}; use lightning::ln::functional_test_utils::*; use lightning::ln::msgs::ChannelMessageHandler; use lightning::routing::router::{PaymentParameters, RouteParameters, find_route}; - use lightning::util::events::{MessageSendEvent, MessageSendEventsProvider, Event}; use lightning::util::test_utils; use lightning::util::config::UserConfig; use crate::utils::create_invoice_from_channelmanager_and_duration_since_epoch; use std::collections::HashSet; + #[test] + fn test_prefer_current_channel() { + // No minimum, prefer larger candidate channel. + assert_eq!(crate::utils::prefer_current_channel(None, 100, 200), false); + + // No minimum, prefer larger current channel. + assert_eq!(crate::utils::prefer_current_channel(None, 200, 100), true); + + // Minimum set, prefer current channel over minimum + buffer. + assert_eq!(crate::utils::prefer_current_channel(Some(100), 115, 100), true); + + // Minimum set, prefer candidate channel over minimum + buffer. + assert_eq!(crate::utils::prefer_current_channel(Some(100), 105, 125), false); + + // Minimum set, both channels sufficient, prefer smaller current channel. + assert_eq!(crate::utils::prefer_current_channel(Some(100), 115, 125), true); + + // Minimum set, both channels sufficient, prefer smaller candidate channel. + assert_eq!(crate::utils::prefer_current_channel(Some(100), 200, 160), false); + + // Minimum set, neither sufficient, prefer larger current channel. + assert_eq!(crate::utils::prefer_current_channel(Some(200), 100, 50), true); + + // Minimum set, neither sufficient, prefer larger candidate channel. + assert_eq!(crate::utils::prefer_current_channel(Some(200), 100, 150), false); + } + + #[test] fn test_from_channelmanager() { let chanmon_cfgs = create_chanmon_cfgs(2); @@ -891,17 +962,19 @@ mod test { } #[test] - fn test_hints_has_only_highest_inbound_capacity_channel() { + fn test_hints_has_only_lowest_inbound_capacity_channel_above_minimum() { 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); - let _chan_1_0_low_inbound_capacity = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 0, 100_000, 0); - let chan_1_0_high_inbound_capacity = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 0, 10_000_000, 0); - let _chan_1_0_medium_inbound_capacity = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 0, 1_000_000, 0); + + let _chan_1_0_inbound_below_amt = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 0, 10_000, 0); + let _chan_1_0_large_inbound_above_amt = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 0, 500_000, 0); + let chan_1_0_low_inbound_above_amt = create_unannounced_chan_between_nodes_with_value(&nodes, 1, 0, 200_000, 0); + let mut scid_aliases = HashSet::new(); - scid_aliases.insert(chan_1_0_high_inbound_capacity.0.short_channel_id_alias.unwrap()); - match_invoice_routes(Some(5000), &nodes[0], scid_aliases); + scid_aliases.insert(chan_1_0_low_inbound_above_amt.0.short_channel_id_alias.unwrap()); + match_invoice_routes(Some(100_000_000), &nodes[0], scid_aliases); } #[test] @@ -1474,7 +1547,7 @@ mod test { #[test] #[cfg(feature = "std")] - fn test_multi_node_hints_has_only_highest_inbound_capacity_channel() { + fn test_multi_node_hints_has_only_lowest_inbound_channel_above_minimum() { let mut chanmon_cfgs = create_chanmon_cfgs(3); let seed_1 = [42u8; 32]; let seed_2 = [43u8; 32]; @@ -1485,17 +1558,17 @@ mod test { let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]); let nodes = create_network(3, &node_cfgs, &node_chanmgrs); - let _chan_0_1_low_inbound_capacity = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 100_000, 0); - let chan_0_1_high_inbound_capacity = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000_000, 0); - let _chan_0_1_medium_inbound_capacity = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0); + let _chan_0_1_below_amt = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 100_000, 0); + let _chan_0_1_above_amt_high_inbound = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 500_000, 0); + let chan_0_1_above_amt_low_inbound = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 180_000, 0); let chan_0_2 = create_unannounced_chan_between_nodes_with_value(&nodes, 0, 2, 100000, 10001); let mut scid_aliases = HashSet::new(); - scid_aliases.insert(chan_0_1_high_inbound_capacity.0.short_channel_id_alias.unwrap()); + scid_aliases.insert(chan_0_1_above_amt_low_inbound.0.short_channel_id_alias.unwrap()); scid_aliases.insert(chan_0_2.0.short_channel_id_alias.unwrap()); match_multi_node_invoice_routes( - Some(10_000), + Some(100_000_000), &nodes[1], vec![&nodes[1], &nodes[2],], scid_aliases,