X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Frouting%2Frouter.rs;h=a97e1b6ffa45db704b89505cfce7d6c58cc1f16b;hb=f75b6cb9a8de91594fec9e37f0b2a4bae36b246a;hp=ed424a2acbec2f713154b03f6ccb0a261e418b3f;hpb=bd6b710328ec6d116d43162ac6922e5b007e3e3c;p=rust-lightning diff --git a/lightning/src/routing/router.rs b/lightning/src/routing/router.rs index ed424a2a..a97e1b6f 100644 --- a/lightning/src/routing/router.rs +++ b/lightning/src/routing/router.rs @@ -231,11 +231,20 @@ pub struct PaymentParameters { /// a lower value prefers to send larger MPP parts, potentially saturating channels and /// increasing failure probability for those paths. /// + /// Note that this restriction will be relaxed during pathfinding after paths which meet this + /// restriction have been found. While paths which meet this criteria will be searched for, it + /// is ultimately up to the scorer to select them over other paths. + /// /// 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 pub max_channel_saturation_power_of_half: u8, + + /// A list of SCIDs which this payment was previously attempted over and which caused the + /// payment to fail. Future attempts for the same payment shouldn't be relayed through any of + /// these SCIDs. + pub previously_failed_channels: Vec, } impl_writeable_tlv_based!(PaymentParameters, { @@ -246,6 +255,7 @@ impl_writeable_tlv_based!(PaymentParameters, { (4, route_hints, vec_type), (5, max_channel_saturation_power_of_half, (default_value, 1)), (6, expiry_time, option), + (7, previously_failed_channels, vec_type), }); impl PaymentParameters { @@ -258,11 +268,8 @@ impl PaymentParameters { expiry_time: None, max_total_cltv_expiry_delta: DEFAULT_MAX_TOTAL_CLTV_EXPIRY_DELTA, max_path_count: DEFAULT_MAX_PATH_COUNT, - #[cfg(test)] // Many tests were written prior to the introduction of this parameter, so - // we leave it as 0 by default in tests, and change it for a few. - max_channel_saturation_power_of_half: 0, - #[cfg(not(test))] max_channel_saturation_power_of_half: 1, + previously_failed_channels: Vec::new(), } } @@ -305,6 +312,13 @@ impl PaymentParameters { pub fn with_max_path_count(self, max_path_count: u8) -> Self { Self { max_path_count, ..self } } + + /// Includes a limit for the maximum number of payment paths that may be used. + /// + /// (C-not exported) since bindings don't support move semantics + pub fn with_max_channel_saturation_power_of_half(self, max_channel_saturation_power_of_half: u8) -> Self { + Self { max_channel_saturation_power_of_half, ..self } + } } /// A list of hops along a payment path terminating with a channel to the recipient. @@ -487,6 +501,17 @@ fn max_htlc_from_capacity(capacity: EffectiveCapacity, max_channel_saturation_po } } +fn iter_equal(mut iter_a: I1, mut iter_b: I2) +-> bool where I1::Item: PartialEq { + loop { + let a = iter_a.next(); + let b = iter_b.next(); + if a.is_none() && b.is_none() { return true; } + if a.is_none() || b.is_none() { return false; } + if a.unwrap().ne(&b.unwrap()) { return false; } + } +} + /// It's useful to keep track of the hops associated with the fees required to use them, /// so that we can choose cheaper paths (as per Dijkstra's algorithm). /// Fee values should be updated only in the context of the whole path, see update_value_and_recompute_fees. @@ -594,10 +619,9 @@ impl<'a> PaymentPath<'a> { // to the fees being paid not lining up with the actual limits. // // Note that this function is not aware of the available_liquidity limit, and thus does not - // support increasing the value being transferred. + // support increasing the value being transferred beyond what was selected during the initial + // routing passes. fn update_value_and_recompute_fees(&mut self, value_msat: u64) { - assert!(value_msat <= self.hops.last().unwrap().0.fee_msat); - let mut total_fee_paid_msat = 0 as u64; for i in (0..self.hops.len()).rev() { let last_hop = i == self.hops.len() - 1; @@ -905,6 +929,11 @@ where L::Target: Logger { final_value_msat }; + // When we start collecting routes we enforce the max_channel_saturation_power_of_half + // requirement strictly. After we've collected enough (or if we fail to find new routes) we + // drop the requirement by setting this to 0. + let mut channel_saturation_pow_half = payment_params.max_channel_saturation_power_of_half; + // Keep track of how much liquidity has been used in selected channels. Used to determine // if the channel can be used by additional MPP paths or to inform path finding decisions. It is // aware of direction *only* to ensure that the correct htlc_maximum_msat value is used. Hence, @@ -958,7 +987,7 @@ where L::Target: Logger { if $src_node_id != $dest_node_id { let short_channel_id = $candidate.short_channel_id(); let effective_capacity = $candidate.effective_capacity(); - let htlc_maximum_msat = max_htlc_from_capacity(effective_capacity, payment_params.max_channel_saturation_power_of_half); + let htlc_maximum_msat = max_htlc_from_capacity(effective_capacity, channel_saturation_pow_half); // It is tricky to subtract $next_hops_fee_msat from available liquidity here. // It may be misleading because we might later choose to reduce the value transferred @@ -980,7 +1009,7 @@ where L::Target: Logger { let contributes_sufficient_value = available_value_contribution_msat >= minimal_value_contribution_msat; // Do not consider candidate hops that would exceed the maximum path length. let path_length_to_node = $next_hops_path_length + 1; - let doesnt_exceed_max_path_length = path_length_to_node <= MAX_PATH_LENGTH_ESTIMATE; + let exceeds_max_path_length = path_length_to_node > MAX_PATH_LENGTH_ESTIMATE; // Do not consider candidates that exceed the maximum total cltv expiry limit. // In order to already account for some of the privacy enhancing random CLTV @@ -991,7 +1020,7 @@ where L::Target: Logger { .unwrap_or(payment_params.max_total_cltv_expiry_delta - final_cltv_expiry_delta); let hop_total_cltv_delta = ($next_hops_cltv_delta as u32) .saturating_add($candidate.cltv_expiry_delta()); - let doesnt_exceed_cltv_delta_limit = hop_total_cltv_delta <= max_total_cltv_expiry_delta; + let exceeds_cltv_delta_limit = hop_total_cltv_delta > max_total_cltv_expiry_delta; let value_contribution_msat = cmp::min(available_value_contribution_msat, $next_hops_value_contribution); // Includes paying fees for the use of the following channels. @@ -1011,15 +1040,19 @@ where L::Target: Logger { (amount_to_transfer_over_msat < $next_hops_path_htlc_minimum_msat && recommended_value_msat > $next_hops_path_htlc_minimum_msat)); + let payment_failed_on_this_channel = + payment_params.previously_failed_channels.contains(&short_channel_id); + // If HTLC minimum is larger than the amount we're going to transfer, we shouldn't // bother considering this channel. If retrying with recommended_value_msat may // allow us to hit the HTLC minimum limit, set htlc_minimum_limit so that we go // around again with a higher amount. - if contributes_sufficient_value && doesnt_exceed_max_path_length && - doesnt_exceed_cltv_delta_limit && may_overpay_to_meet_path_minimum_msat { + if !contributes_sufficient_value || exceeds_max_path_length || + exceeds_cltv_delta_limit || payment_failed_on_this_channel { + // Path isn't useful, ignore it and move on. + } else if may_overpay_to_meet_path_minimum_msat { hit_minimum_limit = true; - } else if contributes_sufficient_value && doesnt_exceed_max_path_length && - doesnt_exceed_cltv_delta_limit && over_path_minimum_msat { + } else if over_path_minimum_msat { // Note that low contribution here (limited by available_liquidity_msat) // might violate htlc_minimum_msat on the hops which are next along the // payment path (upstream to the payee). To avoid that, we recompute @@ -1530,8 +1563,7 @@ where L::Target: Logger { .and_modify(|used_liquidity_msat| *used_liquidity_msat += spent_on_hop_msat) .or_insert(spent_on_hop_msat); let hop_capacity = hop.candidate.effective_capacity(); - let hop_max_msat = max_htlc_from_capacity(hop_capacity, - payment_params.max_channel_saturation_power_of_half); + let hop_max_msat = max_htlc_from_capacity(hop_capacity, channel_saturation_pow_half); if *used_liquidity_msat == hop_max_msat { // If this path used all of this channel's available liquidity, we know // this path will not be selected again in the next loop iteration. @@ -1578,6 +1610,10 @@ where L::Target: Logger { } if !allow_mpp { + if !found_new_path && channel_saturation_pow_half != 0 { + channel_saturation_pow_half = 0; + continue 'paths_collection; + } // If we don't support MPP, no use trying to gather more value ever. break 'paths_collection; } @@ -1587,7 +1623,9 @@ where L::Target: Logger { // iteration. // In the latter case, making another path finding attempt won't help, // because we deterministically terminated the search due to low liquidity. - if already_collected_value_msat >= recommended_value_msat || !found_new_path { + if !found_new_path && channel_saturation_pow_half != 0 { + channel_saturation_pow_half = 0; + } else if already_collected_value_msat >= recommended_value_msat || !found_new_path { log_trace!(logger, "Have now collected {} msat (seeking {} msat) in paths. Last path loop {} a new path.", already_collected_value_msat, recommended_value_msat, if found_new_path { "found" } else { "did not find" }); break 'paths_collection; @@ -1703,8 +1741,32 @@ where L::Target: Logger { // Step (9). // Select the best route by lowest total cost. drawn_routes.sort_unstable_by_key(|paths| paths.iter().map(|path| path.get_cost_msat()).sum::()); + let selected_route = drawn_routes.first_mut().unwrap(); + + // Sort by the path itself and combine redundant paths. + // Note that we sort by SCIDs alone as its simpler but when combining we have to ensure we + // compare both SCIDs and NodeIds as individual nodes may use random aliases causing collisions + // across nodes. + selected_route.sort_unstable_by_key(|path| { + let mut key = [0u64; MAX_PATH_LENGTH_ESTIMATE as usize]; + debug_assert!(path.hops.len() <= key.len()); + for (scid, key) in path.hops.iter().map(|h| h.0.candidate.short_channel_id()).zip(key.iter_mut()) { + *key = scid; + } + key + }); + for idx in 0..(selected_route.len() - 1) { + if idx + 1 >= selected_route.len() { break; } + if iter_equal(selected_route[idx ].hops.iter().map(|h| (h.0.candidate.short_channel_id(), h.0.node_id)), + selected_route[idx + 1].hops.iter().map(|h| (h.0.candidate.short_channel_id(), h.0.node_id))) { + let new_value = selected_route[idx].get_value_msat() + selected_route[idx + 1].get_value_msat(); + selected_route[idx].update_value_and_recompute_fees(new_value); + selected_route.remove(idx + 1); + } + } + let mut selected_paths = Vec::>>::new(); - for payment_path in drawn_routes.first().unwrap() { + for payment_path in selected_route { let mut path = payment_path.hops.iter().map(|(payment_hop, node_features)| { Ok(RouteHop { pubkey: PublicKey::from_slice(payment_hop.node_id.as_slice()).map_err(|_| LightningError{err: format!("Public key {:?} is invalid", &payment_hop.node_id), action: ErrorAction::IgnoreAndLog(Level::Trace)})?, @@ -1909,7 +1971,7 @@ fn build_route_from_hops_internal( #[cfg(test)] mod tests { - use routing::gossip::{NetworkGraph, P2PGossipSync, NodeId}; + use routing::gossip::{NetworkGraph, P2PGossipSync, NodeId, EffectiveCapacity}; use routing::router::{get_route, build_route_from_hops_internal, add_random_cltv_offset, default_node_features, PaymentParameters, Route, RouteHint, RouteHintHop, RouteHop, RoutingFees, DEFAULT_MAX_TOTAL_CLTV_EXPIRY_DELTA, MAX_PATH_LENGTH_ESTIMATE}; @@ -1942,6 +2004,8 @@ mod tests { use prelude::*; use sync::{self, Arc}; + use core::convert::TryInto; + fn get_channel_details(short_channel_id: Option, node_id: PublicKey, features: InitFeatures, outbound_capacity_msat: u64) -> channelmanager::ChannelDetails { channelmanager::ChannelDetails { @@ -4790,17 +4854,18 @@ mod tests { // Get a route for 100 sats and check that we found the MPP route no problem and didn't // overpay at all. - let route = get_route(&our_id, &payment_params, &network_graph.read_only(), None, 100_000, 42, Arc::clone(&logger), &scorer, &random_seed_bytes).unwrap(); + let mut route = get_route(&our_id, &payment_params, &network_graph.read_only(), None, 100_000, 42, Arc::clone(&logger), &scorer, &random_seed_bytes).unwrap(); assert_eq!(route.paths.len(), 2); - // Paths are somewhat randomly ordered, but: - // * the first is channel 2 (1 msat fee) -> channel 4 -> channel 42 - // * the second is channel 1 (0 fee, but 99 sat maximum) -> channel 3 -> channel 42 - assert_eq!(route.paths[0][0].short_channel_id, 2); - assert_eq!(route.paths[0][0].fee_msat, 1); - assert_eq!(route.paths[0][2].fee_msat, 1_000); - assert_eq!(route.paths[1][0].short_channel_id, 1); - assert_eq!(route.paths[1][0].fee_msat, 0); - assert_eq!(route.paths[1][2].fee_msat, 99_000); + route.paths.sort_by_key(|path| path[0].short_channel_id); + // Paths are manually ordered ordered by SCID, so: + // * the first is channel 1 (0 fee, but 99 sat maximum) -> channel 3 -> channel 42 + // * the second is channel 2 (1 msat fee) -> channel 4 -> channel 42 + assert_eq!(route.paths[0][0].short_channel_id, 1); + assert_eq!(route.paths[0][0].fee_msat, 0); + assert_eq!(route.paths[0][2].fee_msat, 99_000); + assert_eq!(route.paths[1][0].short_channel_id, 2); + assert_eq!(route.paths[1][0].fee_msat, 1); + assert_eq!(route.paths[1][2].fee_msat, 1_000); assert_eq!(route.get_total_fees(), 1); assert_eq!(route.get_total_amount(), 100_000); } @@ -4814,7 +4879,8 @@ mod tests { let scorer = test_utils::TestScorer::with_penalty(0); let keys_manager = test_utils::TestKeysInterface::new(&[0u8; 32], Network::Testnet); let random_seed_bytes = keys_manager.get_secure_random_bytes(); - let payment_params = PaymentParameters::from_node_id(nodes[2]).with_features(InvoiceFeatures::known()); + let payment_params = PaymentParameters::from_node_id(nodes[2]).with_features(InvoiceFeatures::known()) + .with_max_channel_saturation_power_of_half(0); // We need a route consisting of 3 paths: // From our node to node2 via node0, node7, node1 (three paths one hop each). @@ -5262,12 +5328,13 @@ mod tests { assert_eq!(route.paths[0].len(), 1); assert_eq!(route.paths[1].len(), 1); + assert!((route.paths[0][0].short_channel_id == 3 && route.paths[1][0].short_channel_id == 2) || + (route.paths[0][0].short_channel_id == 2 && route.paths[1][0].short_channel_id == 3)); + assert_eq!(route.paths[0][0].pubkey, nodes[0]); - assert_eq!(route.paths[0][0].short_channel_id, 3); assert_eq!(route.paths[0][0].fee_msat, 50_000); assert_eq!(route.paths[1][0].pubkey, nodes[0]); - assert_eq!(route.paths[1][0].short_channel_id, 2); assert_eq!(route.paths[1][0].fee_msat, 50_000); } @@ -5519,6 +5586,35 @@ mod tests { } } + #[test] + fn avoids_recently_failed_paths() { + // Ensure that the router always avoids all of the `previously_failed_channels` channels by + // randomly inserting channels into it until we can't find a route anymore. + let (secp_ctx, network, _, _, logger) = build_graph(); + let (_, our_id, _, nodes) = get_nodes(&secp_ctx); + let network_graph = network.read_only(); + + let scorer = test_utils::TestScorer::with_penalty(0); + let mut payment_params = PaymentParameters::from_node_id(nodes[6]).with_route_hints(last_hops(&nodes)) + .with_max_path_count(1); + let keys_manager = test_utils::TestKeysInterface::new(&[0u8; 32], Network::Testnet); + let random_seed_bytes = keys_manager.get_secure_random_bytes(); + + // We should be able to find a route initially, and then after we fail a few random + // channels eventually we won't be able to any longer. + assert!(get_route(&our_id, &payment_params, &network_graph, None, 100, 0, Arc::clone(&logger), &scorer, &random_seed_bytes).is_ok()); + loop { + if let Ok(route) = get_route(&our_id, &payment_params, &network_graph, None, 100, 0, Arc::clone(&logger), &scorer, &random_seed_bytes) { + for chan in route.paths[0].iter() { + assert!(!payment_params.previously_failed_channels.contains(&chan.short_channel_id)); + } + let victim = (u64::from_ne_bytes(random_seed_bytes[0..8].try_into().unwrap()) as usize) + % route.paths[0].len(); + payment_params.previously_failed_channels.push(route.paths[0][victim].short_channel_id); + } else { break; } + } + } + #[test] fn limits_path_length() { let (secp_ctx, network, _, _, logger) = build_line_graph(); @@ -5668,6 +5764,50 @@ mod tests { } } + #[test] + fn avoids_saturating_channels() { + let (secp_ctx, network_graph, gossip_sync, _, logger) = build_graph(); + let (_, our_id, privkeys, nodes) = get_nodes(&secp_ctx); + + let scorer = ProbabilisticScorer::new(Default::default(), &*network_graph, Arc::clone(&logger)); + + // Set the fee on channel 13 to 100% to match channel 4 giving us two equivalent paths (us + // -> node 7 -> node2 and us -> node 1 -> node 2) which we should balance over. + update_channel(&gossip_sync, &secp_ctx, &privkeys[1], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 4, + timestamp: 2, + flags: 0, + cltv_expiry_delta: (4 << 4) | 1, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(200_000_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + update_channel(&gossip_sync, &secp_ctx, &privkeys[7], UnsignedChannelUpdate { + chain_hash: genesis_block(Network::Testnet).header.block_hash(), + short_channel_id: 13, + timestamp: 2, + flags: 0, + cltv_expiry_delta: (13 << 4) | 1, + htlc_minimum_msat: 0, + htlc_maximum_msat: OptionalField::Present(200_000_000), + fee_base_msat: 0, + fee_proportional_millionths: 0, + excess_data: Vec::new() + }); + + 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(); + 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)); + } + #[cfg(not(feature = "no-std"))] pub(super) fn random_init_seed() -> u64 { // Because the default HashMap in std pulls OS randomness, we can use it as a (bad) RNG. @@ -5754,7 +5894,7 @@ mod tests { } #[test] - fn avoids_banned_nodes() { + fn honors_manual_penalties() { let (secp_ctx, network_graph, _, _, logger) = build_line_graph(); let (_, our_id, _, nodes) = get_nodes(&secp_ctx); @@ -5764,7 +5904,17 @@ mod tests { let scorer_params = ProbabilisticScoringParameters::default(); let mut scorer = ProbabilisticScorer::new(scorer_params, Arc::clone(&network_graph), Arc::clone(&logger)); - // First check we can get a route. + // First check set manual penalties are returned by the scorer. + let usage = ChannelUsage { + amount_msat: 0, + inflight_htlc_msat: 0, + effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024_000, htlc_maximum_msat: Some(1_000) }, + }; + scorer.set_manual_penalty(&NodeId::from_pubkey(&nodes[3]), 123); + scorer.set_manual_penalty(&NodeId::from_pubkey(&nodes[4]), 456); + assert_eq!(scorer.channel_penalty_msat(42, &NodeId::from_pubkey(&nodes[3]), &NodeId::from_pubkey(&nodes[4]), usage), 456); + + // Then check we can get a normal route let payment_params = PaymentParameters::from_node_id(nodes[10]); let route = get_route(&our_id, &payment_params, &network_graph.read_only(), None, 100, 42, Arc::clone(&logger), &scorer, &random_seed_bytes); assert!(route.is_ok());