X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Frouting%2Fscoring.rs;h=7504e0840d2683125cf75144fd445b070c6f08da;hb=10e06331f3f392a5dd38f20601f728a072870d69;hp=5b829f61eb7536fc72f6adb350bd1ecaaba48646;hpb=ad7ff0b23d49cb654935ecdfa8a23097107bcabd;p=rust-lightning diff --git a/lightning/src/routing/scoring.rs b/lightning/src/routing/scoring.rs index 5b829f61..7504e084 100644 --- a/lightning/src/routing/scoring.rs +++ b/lightning/src/routing/scoring.rs @@ -20,7 +20,7 @@ //! # use lightning::routing::gossip::NetworkGraph; //! # use lightning::routing::router::{RouteParameters, find_route}; //! # use lightning::routing::scoring::{ProbabilisticScorer, ProbabilisticScoringParameters}; -//! # use lightning::chain::keysinterface::{KeysManager, KeysInterface}; +//! # use lightning::chain::keysinterface::KeysManager; //! # use lightning::util::logger::{Logger, Record}; //! # use bitcoin::secp256k1::PublicKey; //! # @@ -260,7 +260,7 @@ impl<'a, S: Writeable> Writeable for MutexGuard<'a, S> { } /// Proposed use of a channel passed as a parameter to [`Score::channel_penalty_msat`]. -#[derive(Clone, Copy, Debug)] +#[derive(Clone, Copy, Debug, PartialEq)] pub struct ChannelUsage { /// The amount to send through the channel, denominated in millisatoshis. pub amount_msat: u64, @@ -597,7 +597,22 @@ struct HistoricalMinMaxBuckets<'a> { impl HistoricalMinMaxBuckets<'_> { #[inline] - fn calculate_success_probability_times_billion(&self, required_decays: u32, payment_amt_64th_bucket: u8) -> Option { + fn get_decayed_buckets(&self, now: T, last_updated: T, half_life: Duration) + -> ([u16; 8], [u16; 8], u32) { + let required_decays = now.duration_since(last_updated).as_secs() + .checked_div(half_life.as_secs()) + .map_or(u32::max_value(), |decays| cmp::min(decays, u32::max_value() as u64) as u32); + let mut min_buckets = *self.min_liquidity_offset_history; + min_buckets.time_decay_data(required_decays); + let mut max_buckets = *self.max_liquidity_offset_history; + max_buckets.time_decay_data(required_decays); + (min_buckets.buckets, max_buckets.buckets, required_decays) + } + + #[inline] + fn calculate_success_probability_times_billion( + &self, now: T, last_updated: T, half_life: Duration, payment_amt_64th_bucket: u8) + -> Option { // If historical penalties are enabled, calculate the penalty by walking the set of // historical liquidity bucket (min, max) combinations (where min_idx < max_idx) and, for // each, calculate the probability of success given our payment amount, then total the @@ -619,23 +634,22 @@ impl HistoricalMinMaxBuckets<'_> { // less than 1/16th of a channel's capacity, or 1/8th if we used the top of the bucket. let mut total_valid_points_tracked = 0; - // Rather than actually decaying the individual buckets, which would lose precision, we - // simply track whether all buckets would be decayed to zero, in which case we treat it as - // if we had no data. - let mut is_fully_decayed = true; - let mut check_track_bucket_contains_undecayed_points = - |bucket_val: u16| if bucket_val.checked_shr(required_decays).unwrap_or(0) > 0 { is_fully_decayed = false; }; + // Check if all our buckets are zero, once decayed and treat it as if we had no data. We + // don't actually use the decayed buckets, though, as that would lose precision. + let (decayed_min_buckets, decayed_max_buckets, required_decays) = + self.get_decayed_buckets(now, last_updated, half_life); + if decayed_min_buckets.iter().all(|v| *v == 0) || decayed_max_buckets.iter().all(|v| *v == 0) { + return None; + } for (min_idx, min_bucket) in self.min_liquidity_offset_history.buckets.iter().enumerate() { - check_track_bucket_contains_undecayed_points(*min_bucket); for max_bucket in self.max_liquidity_offset_history.buckets.iter().take(8 - min_idx) { total_valid_points_tracked += (*min_bucket as u64) * (*max_bucket as u64); - check_track_bucket_contains_undecayed_points(*max_bucket); } } // If the total valid points is smaller than 1.0 (i.e. 32 in our fixed-point scheme), treat // it as if we were fully decayed. - if total_valid_points_tracked.checked_shr(required_decays).unwrap_or(0) < 32*32 || is_fully_decayed { + if total_valid_points_tracked.checked_shr(required_decays).unwrap_or(0) < 32*32 { return None; } @@ -717,6 +731,8 @@ impl>, L: Deref, T: Time> ProbabilisticScorerU /// Note that this writes roughly one line per channel for which we have a liquidity estimate, /// which may be a substantial amount of log output. pub fn debug_log_liquidity_stats(&self) { + let now = T::now(); + let graph = self.network_graph.read_only(); for (scid, liq) in self.channel_liquidities.iter() { if let Some(chan_debug) = graph.channels().get(scid) { @@ -724,8 +740,25 @@ impl>, L: Deref, T: Time> ProbabilisticScorerU if let Some((directed_info, _)) = chan_debug.as_directed_to(target) { let amt = directed_info.effective_capacity().as_msat(); let dir_liq = liq.as_directed(source, target, amt, &self.params); - log_debug!(self.logger, "Liquidity from {:?} to {:?} via {} is in the range ({}, {})", - source, target, scid, dir_liq.min_liquidity_msat(), dir_liq.max_liquidity_msat()); + + let buckets = HistoricalMinMaxBuckets { + min_liquidity_offset_history: &dir_liq.min_liquidity_offset_history, + max_liquidity_offset_history: &dir_liq.max_liquidity_offset_history, + }; + let (min_buckets, max_buckets, _) = buckets.get_decayed_buckets(now, + *dir_liq.last_updated, self.params.historical_no_updates_half_life); + + log_debug!(self.logger, core::concat!( + "Liquidity from {} to {} via {} is in the range ({}, {}).\n", + "\tHistorical min liquidity octile relative probabilities: {} {} {} {} {} {} {} {}\n", + "\tHistorical max liquidity octile relative probabilities: {} {} {} {} {} {} {} {}"), + source, target, scid, dir_liq.min_liquidity_msat(), dir_liq.max_liquidity_msat(), + min_buckets[0], min_buckets[1], min_buckets[2], min_buckets[3], + min_buckets[4], min_buckets[5], min_buckets[6], min_buckets[7], + // Note that the liquidity buckets are an offset from the edge, so we + // inverse the max order to get the probabilities from zero. + max_buckets[7], max_buckets[6], max_buckets[5], max_buckets[4], + max_buckets[3], max_buckets[2], max_buckets[1], max_buckets[0]); } else { log_debug!(self.logger, "No amount known for SCID {} from {:?} to {:?}", scid, source, target); } @@ -756,6 +789,53 @@ impl>, L: Deref, T: Time> ProbabilisticScorerU None } + /// Query the historical estimated minimum and maximum liquidity available for sending a + /// payment over the channel with `scid` towards the given `target` node. + /// + /// Returns two sets of 8 buckets. The first set describes the octiles for lower-bound + /// liquidity estimates, the second set describes the octiles for upper-bound liquidity + /// estimates. Each bucket describes the relative frequency at which we've seen a liquidity + /// bound in the octile relative to the channel's total capacity, on an arbitrary scale. + /// Because the values are slowly decayed, more recent data points are weighted more heavily + /// than older datapoints. + /// + /// When scoring, the estimated probability that an upper-/lower-bound lies in a given octile + /// relative to the channel's total capacity is calculated by dividing that bucket's value with + /// the total of all buckets for the given bound. + /// + /// For example, a value of `[0, 0, 0, 0, 0, 0, 32]` indicates that we believe the probability + /// of a bound being in the top octile to be 100%, and have never (recently) seen it in any + /// other octiles. A value of `[31, 0, 0, 0, 0, 0, 0, 32]` indicates we've seen the bound being + /// both in the top and bottom octile, and roughly with similar (recent) frequency. + /// + /// Because the datapoints are decayed slowly over time, values will eventually return to + /// `Some(([0; 8], [0; 8]))`. + pub fn historical_estimated_channel_liquidity_probabilities(&self, scid: u64, target: &NodeId) + -> Option<([u16; 8], [u16; 8])> { + let graph = self.network_graph.read_only(); + + if let Some(chan) = graph.channels().get(&scid) { + if let Some(liq) = self.channel_liquidities.get(&scid) { + if let Some((directed_info, source)) = chan.as_directed_to(target) { + let amt = directed_info.effective_capacity().as_msat(); + let dir_liq = liq.as_directed(source, target, amt, &self.params); + + let buckets = HistoricalMinMaxBuckets { + min_liquidity_offset_history: &dir_liq.min_liquidity_offset_history, + max_liquidity_offset_history: &dir_liq.max_liquidity_offset_history, + }; + let (min_buckets, mut max_buckets, _) = buckets.get_decayed_buckets(T::now(), + *dir_liq.last_updated, self.params.historical_no_updates_half_life); + // Note that the liquidity buckets are an offset from the edge, so we inverse + // the max order to get the probabilities from zero. + max_buckets.reverse(); + return Some((min_buckets, max_buckets)); + } + } + } + None + } + /// Marks the node with the given `node_id` as banned, i.e., /// it will be avoided during path finding. pub fn add_banned(&mut self, node_id: &NodeId) { @@ -942,9 +1022,6 @@ impl, BRT: Deref, if params.historical_liquidity_penalty_multiplier_msat != 0 || params.historical_liquidity_penalty_amount_multiplier_msat != 0 { - let required_decays = self.now.duration_since(*self.last_updated).as_secs() - .checked_div(params.historical_no_updates_half_life.as_secs()) - .map_or(u32::max_value(), |decays| cmp::min(decays, u32::max_value() as u64) as u32); let payment_amt_64th_bucket = amount_msat * 64 / self.capacity_msat; debug_assert!(payment_amt_64th_bucket <= 64); if payment_amt_64th_bucket > 64 { return res; } @@ -954,7 +1031,9 @@ impl, BRT: Deref, max_liquidity_offset_history: &self.max_liquidity_offset_history, }; if let Some(cumulative_success_prob_times_billion) = buckets - .calculate_success_probability_times_billion(required_decays, payment_amt_64th_bucket as u8) { + .calculate_success_probability_times_billion(self.now, *self.last_updated, + params.historical_no_updates_half_life, payment_amt_64th_bucket as u8) + { let historical_negative_log10_times_2048 = approx::negative_log10_times_2048(cumulative_success_prob_times_billion + 1, 1024 * 1024 * 1024); res = res.saturating_add(Self::combined_penalty_msat(amount_msat, historical_negative_log10_times_2048, params.historical_liquidity_penalty_multiplier_msat, @@ -1143,31 +1222,32 @@ impl>, L: Deref, T: Time> Score for Probabilis .get(&hop.short_channel_id) .and_then(|channel| channel.as_directed_to(&target)); - if hop.short_channel_id == short_channel_id && hop_idx == 0 { + let at_failed_channel = hop.short_channel_id == short_channel_id; + if at_failed_channel && hop_idx == 0 { log_warn!(self.logger, "Payment failed at the first hop - we do not attempt to learn channel info in such cases as we can directly observe local state.\n\tBecause we know the local state, we should generally not see failures here - this may be an indication that your channel peer on channel {} is broken and you may wish to close the channel.", hop.short_channel_id); } // Only score announced channels. if let Some((channel, source)) = channel_directed_from_source { let capacity_msat = channel.effective_capacity().as_msat(); - if hop.short_channel_id == short_channel_id { + if at_failed_channel { self.channel_liquidities .entry(hop.short_channel_id) .or_insert_with(ChannelLiquidity::new) .as_directed_mut(source, &target, capacity_msat, &self.params) .failed_at_channel(amount_msat, format_args!("SCID {}, towards {:?}", hop.short_channel_id, target), &self.logger); - break; + } else { + self.channel_liquidities + .entry(hop.short_channel_id) + .or_insert_with(ChannelLiquidity::new) + .as_directed_mut(source, &target, capacity_msat, &self.params) + .failed_downstream(amount_msat, format_args!("SCID {}, towards {:?}", hop.short_channel_id, target), &self.logger); } - - self.channel_liquidities - .entry(hop.short_channel_id) - .or_insert_with(ChannelLiquidity::new) - .as_directed_mut(source, &target, capacity_msat, &self.params) - .failed_downstream(amount_msat, format_args!("SCID {}, towards {:?}", hop.short_channel_id, target), &self.logger); } else { log_debug!(self.logger, "Not able to penalize channel with SCID {} as we do not have graph info for it (likely a route-hint last-hop).", hop.short_channel_id); } + if at_failed_channel { break; } } } @@ -1601,6 +1681,7 @@ impl Readable for ChannelLiquidity { #[cfg(test)] mod tests { use super::{ChannelLiquidity, HistoricalBucketRangeTracker, ProbabilisticScoringParameters, ProbabilisticScorerUsingTime}; + use crate::util::config::UserConfig; use crate::util::time::Time; use crate::util::time::tests::SinceEpoch; @@ -1695,13 +1776,13 @@ mod tests { let node_2_secret = &SecretKey::from_slice(&[40; 32]).unwrap(); let secp_ctx = Secp256k1::new(); let unsigned_announcement = UnsignedChannelAnnouncement { - features: channelmanager::provided_channel_features(), + features: channelmanager::provided_channel_features(&UserConfig::default()), chain_hash: genesis_hash, short_channel_id, - node_id_1: PublicKey::from_secret_key(&secp_ctx, &node_1_key), - node_id_2: PublicKey::from_secret_key(&secp_ctx, &node_2_key), - bitcoin_key_1: PublicKey::from_secret_key(&secp_ctx, &node_1_secret), - bitcoin_key_2: PublicKey::from_secret_key(&secp_ctx, &node_2_secret), + node_id_1: NodeId::from_pubkey(&PublicKey::from_secret_key(&secp_ctx, &node_1_key)), + node_id_2: NodeId::from_pubkey(&PublicKey::from_secret_key(&secp_ctx, &node_2_key)), + bitcoin_key_1: NodeId::from_pubkey(&PublicKey::from_secret_key(&secp_ctx, &node_1_secret)), + bitcoin_key_2: NodeId::from_pubkey(&PublicKey::from_secret_key(&secp_ctx, &node_2_secret)), excess_data: Vec::new(), }; let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]); @@ -1745,32 +1826,23 @@ mod tests { network_graph.update_channel(&signed_update).unwrap(); } + fn path_hop(pubkey: PublicKey, short_channel_id: u64, fee_msat: u64) -> RouteHop { + let config = UserConfig::default(); + RouteHop { + pubkey, + node_features: channelmanager::provided_node_features(&config), + short_channel_id, + channel_features: channelmanager::provided_channel_features(&config), + fee_msat, + cltv_expiry_delta: 18, + } + } + fn payment_path_for_amount(amount_msat: u64) -> Vec { vec![ - RouteHop { - pubkey: source_pubkey(), - node_features: channelmanager::provided_node_features(), - short_channel_id: 41, - channel_features: channelmanager::provided_channel_features(), - fee_msat: 1, - cltv_expiry_delta: 18, - }, - RouteHop { - pubkey: target_pubkey(), - node_features: channelmanager::provided_node_features(), - short_channel_id: 42, - channel_features: channelmanager::provided_channel_features(), - fee_msat: 2, - cltv_expiry_delta: 18, - }, - RouteHop { - pubkey: recipient_pubkey(), - node_features: channelmanager::provided_node_features(), - short_channel_id: 43, - channel_features: channelmanager::provided_channel_features(), - fee_msat: amount_msat, - cltv_expiry_delta: 18, - }, + path_hop(source_pubkey(), 41, 1), + path_hop(target_pubkey(), 42, 2), + path_hop(recipient_pubkey(), 43, amount_msat), ] } @@ -2145,6 +2217,65 @@ mod tests { assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), u64::max_value()); } + #[test] + fn ignores_channels_after_removed_failed_channel() { + // Previously, if we'd tried to send over a channel which was removed from the network + // graph before we call `payment_path_failed` (which is the default if the we get a "no + // such channel" error in the `InvoicePayer`), we would call `failed_downstream` on all + // channels in the route, even ones which they payment never reached. This tests to ensure + // we do not score such channels. + let secp_ctx = Secp256k1::new(); + let logger = TestLogger::new(); + let genesis_hash = genesis_block(Network::Testnet).header.block_hash(); + let mut network_graph = NetworkGraph::new(genesis_hash, &logger); + let secret_a = SecretKey::from_slice(&[42; 32]).unwrap(); + let secret_b = SecretKey::from_slice(&[43; 32]).unwrap(); + let secret_c = SecretKey::from_slice(&[44; 32]).unwrap(); + let secret_d = SecretKey::from_slice(&[45; 32]).unwrap(); + add_channel(&mut network_graph, 42, secret_a, secret_b); + // Don't add the channel from B -> C. + add_channel(&mut network_graph, 44, secret_c, secret_d); + + let pub_a = PublicKey::from_secret_key(&secp_ctx, &secret_a); + let pub_b = PublicKey::from_secret_key(&secp_ctx, &secret_b); + let pub_c = PublicKey::from_secret_key(&secp_ctx, &secret_c); + let pub_d = PublicKey::from_secret_key(&secp_ctx, &secret_d); + + let path = vec![ + path_hop(pub_b, 42, 1), + path_hop(pub_c, 43, 2), + path_hop(pub_d, 44, 100), + ]; + + let node_a = NodeId::from_pubkey(&pub_a); + let node_b = NodeId::from_pubkey(&pub_b); + let node_c = NodeId::from_pubkey(&pub_c); + let node_d = NodeId::from_pubkey(&pub_d); + + let params = ProbabilisticScoringParameters { + liquidity_penalty_multiplier_msat: 1_000, + ..ProbabilisticScoringParameters::zero_penalty() + }; + let mut scorer = ProbabilisticScorer::new(params, &network_graph, &logger); + + let usage = ChannelUsage { + amount_msat: 250, + inflight_htlc_msat: 0, + effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_000, htlc_maximum_msat: 1_000 }, + }; + assert_eq!(scorer.channel_penalty_msat(42, &node_a, &node_b, usage), 128); + // Note that a default liquidity bound is used for B -> C as no channel exists + assert_eq!(scorer.channel_penalty_msat(43, &node_b, &node_c, usage), 128); + assert_eq!(scorer.channel_penalty_msat(44, &node_c, &node_d, usage), 128); + + scorer.payment_path_failed(&path.iter().collect::>(), 43); + + assert_eq!(scorer.channel_penalty_msat(42, &node_a, &node_b, usage), 80); + // Note that a default liquidity bound is used for B -> C as no channel exists + assert_eq!(scorer.channel_penalty_msat(43, &node_b, &node_c, usage), 128); + assert_eq!(scorer.channel_penalty_msat(44, &node_c, &node_d, usage), 128); + } + #[test] fn reduces_liquidity_upper_bound_along_path_on_success() { let logger = TestLogger::new(); @@ -2619,19 +2750,32 @@ mod tests { }; // With no historical data the normal liquidity penalty calculation is used. assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 47); + assert_eq!(scorer.historical_estimated_channel_liquidity_probabilities(42, &target), + None); scorer.payment_path_failed(&payment_path_for_amount(1).iter().collect::>(), 42); assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 2048); + // The "it failed" increment is 32, where the probability should lie fully in the first + // octile. + assert_eq!(scorer.historical_estimated_channel_liquidity_probabilities(42, &target), + Some(([32, 0, 0, 0, 0, 0, 0, 0], [32, 0, 0, 0, 0, 0, 0, 0]))); // Even after we tell the scorer we definitely have enough available liquidity, it will // still remember that there was some failure in the past, and assign a non-0 penalty. scorer.payment_path_failed(&payment_path_for_amount(1000).iter().collect::>(), 43); assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 198); + // The first octile should be decayed just slightly and the last octile has a new point. + assert_eq!(scorer.historical_estimated_channel_liquidity_probabilities(42, &target), + Some(([31, 0, 0, 0, 0, 0, 0, 32], [31, 0, 0, 0, 0, 0, 0, 32]))); // Advance the time forward 16 half-lives (which the docs claim will ensure all data is // gone), and check that we're back to where we started. SinceEpoch::advance(Duration::from_secs(10 * 16)); assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage), 47); + // Once fully decayed we still have data, but its all-0s. In the future we may remove the + // data entirely instead. + assert_eq!(scorer.historical_estimated_channel_liquidity_probabilities(42, &target), + Some(([0; 8], [0; 8]))); } #[test]