1 // This file is Copyright its original authors, visible in version control
4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
7 // You may not use this file except in accordance with one or both of these
10 //! Utilities for scoring payment channels.
12 //! [`ProbabilisticScorer`] may be given to [`find_route`] to score payment channels during path
13 //! finding when a custom [`Score`] implementation is not needed.
18 //! # extern crate bitcoin;
20 //! # use lightning::routing::gossip::NetworkGraph;
21 //! # use lightning::routing::router::{RouteParameters, find_route};
22 //! # use lightning::routing::scoring::{ProbabilisticScorer, ProbabilisticScoringFeeParameters, ProbabilisticScoringDecayParameters};
23 //! # use lightning::sign::KeysManager;
24 //! # use lightning::util::logger::{Logger, Record};
25 //! # use bitcoin::secp256k1::PublicKey;
27 //! # struct FakeLogger {};
28 //! # impl Logger for FakeLogger {
29 //! # fn log(&self, record: &Record) { unimplemented!() }
31 //! # fn find_scored_route(payer: PublicKey, route_params: RouteParameters, network_graph: NetworkGraph<&FakeLogger>) {
32 //! # let logger = FakeLogger {};
34 //! // Use the default channel penalties.
35 //! let params = ProbabilisticScoringFeeParameters::default();
36 //! let decay_params = ProbabilisticScoringDecayParameters::default();
37 //! let scorer = ProbabilisticScorer::new(decay_params, &network_graph, &logger);
39 //! // Or use custom channel penalties.
40 //! let params = ProbabilisticScoringFeeParameters {
41 //! liquidity_penalty_multiplier_msat: 2 * 1000,
42 //! ..ProbabilisticScoringFeeParameters::default()
44 //! let decay_params = ProbabilisticScoringDecayParameters::default();
45 //! let scorer = ProbabilisticScorer::new(decay_params, &network_graph, &logger);
46 //! # let random_seed_bytes = [42u8; 32];
48 //! let route = find_route(&payer, &route_params, &network_graph, None, &logger, &scorer, ¶ms, &random_seed_bytes);
54 //! Persisting when built with feature `no-std` and restoring without it, or vice versa, uses
55 //! different types and thus is undefined.
57 //! [`find_route`]: crate::routing::router::find_route
59 use crate::ln::msgs::DecodeError;
60 use crate::routing::gossip::{EffectiveCapacity, NetworkGraph, NodeId};
61 use crate::routing::router::Path;
62 use crate::util::ser::{Readable, ReadableArgs, Writeable, Writer};
63 use crate::util::logger::Logger;
64 use crate::util::time::Time;
66 use crate::prelude::*;
68 use core::cell::{RefCell, RefMut};
69 use core::convert::TryInto;
70 use core::ops::{Deref, DerefMut};
71 use core::time::Duration;
72 use crate::io::{self, Read};
73 use crate::sync::{Mutex, MutexGuard};
75 /// We define Score ever-so-slightly differently based on whether we are being built for C bindings
76 /// or not. For users, `LockableScore` must somehow be writeable to disk. For Rust users, this is
77 /// no problem - you move a `Score` that implements `Writeable` into a `Mutex`, lock it, and now
78 /// you have the original, concrete, `Score` type, which presumably implements `Writeable`.
80 /// For C users, once you've moved the `Score` into a `LockableScore` all you have after locking it
81 /// is an opaque trait object with an opaque pointer with no type info. Users could take the unsafe
82 /// approach of blindly casting that opaque pointer to a concrete type and calling `Writeable` from
83 /// there, but other languages downstream of the C bindings (e.g. Java) can't even do that.
84 /// Instead, we really want `Score` and `LockableScore` to implement `Writeable` directly, which we
85 /// do here by defining `Score` differently for `cfg(c_bindings)`.
86 macro_rules! define_score { ($($supertrait: path)*) => {
87 /// An interface used to score payment channels for path finding.
89 /// Scoring is in terms of fees willing to be paid in order to avoid routing through a channel.
90 pub trait Score $(: $supertrait)* {
91 /// A configurable type which should contain various passed-in parameters for configuring the scorer,
92 /// on a per-routefinding-call basis through to the scorer methods,
93 /// which are used to determine the parameters for the suitability of channels for use.
95 /// Returns the fee in msats willing to be paid to avoid routing `send_amt_msat` through the
96 /// given channel in the direction from `source` to `target`.
98 /// The channel's capacity (less any other MPP parts that are also being considered for use in
99 /// the same payment) is given by `capacity_msat`. It may be determined from various sources
100 /// such as a chain data, network gossip, or invoice hints. For invoice hints, a capacity near
101 /// [`u64::max_value`] is given to indicate sufficient capacity for the invoice's full amount.
102 /// Thus, implementations should be overflow-safe.
103 fn channel_penalty_msat(
104 &self, short_channel_id: u64, source: &NodeId, target: &NodeId, usage: ChannelUsage, score_params: &Self::ScoreParams
107 /// Handles updating channel penalties after failing to route through a channel.
108 fn payment_path_failed(&mut self, path: &Path, short_channel_id: u64);
110 /// Handles updating channel penalties after successfully routing along a path.
111 fn payment_path_successful(&mut self, path: &Path);
113 /// Handles updating channel penalties after a probe over the given path failed.
114 fn probe_failed(&mut self, path: &Path, short_channel_id: u64);
116 /// Handles updating channel penalties after a probe over the given path succeeded.
117 fn probe_successful(&mut self, path: &Path);
120 impl<S: Score, T: DerefMut<Target=S> $(+ $supertrait)*> Score for T {
121 type ScoreParams = S::ScoreParams;
122 fn channel_penalty_msat(
123 &self, short_channel_id: u64, source: &NodeId, target: &NodeId, usage: ChannelUsage, score_params: &Self::ScoreParams
125 self.deref().channel_penalty_msat(short_channel_id, source, target, usage, score_params)
128 fn payment_path_failed(&mut self, path: &Path, short_channel_id: u64) {
129 self.deref_mut().payment_path_failed(path, short_channel_id)
132 fn payment_path_successful(&mut self, path: &Path) {
133 self.deref_mut().payment_path_successful(path)
136 fn probe_failed(&mut self, path: &Path, short_channel_id: u64) {
137 self.deref_mut().probe_failed(path, short_channel_id)
140 fn probe_successful(&mut self, path: &Path) {
141 self.deref_mut().probe_successful(path)
147 define_score!(Writeable);
148 #[cfg(not(c_bindings))]
151 /// A scorer that is accessed under a lock.
153 /// Needed so that calls to [`Score::channel_penalty_msat`] in [`find_route`] can be made while
154 /// having shared ownership of a scorer but without requiring internal locking in [`Score`]
155 /// implementations. Internal locking would be detrimental to route finding performance and could
156 /// result in [`Score::channel_penalty_msat`] returning a different value for the same channel.
158 /// [`find_route`]: crate::routing::router::find_route
159 pub trait LockableScore<'a> {
160 /// The locked [`Score`] type.
161 type Locked: 'a + Score;
163 /// Returns the locked scorer.
164 fn lock(&'a self) -> Self::Locked;
167 /// Refers to a scorer that is accessible under lock and also writeable to disk
169 /// We need this trait to be able to pass in a scorer to `lightning-background-processor` that will enable us to
170 /// use the Persister to persist it.
171 pub trait WriteableScore<'a>: LockableScore<'a> + Writeable {}
173 #[cfg(not(c_bindings))]
174 impl<'a, T> WriteableScore<'a> for T where T: LockableScore<'a> + Writeable {}
175 /// This is not exported to bindings users
176 impl<'a, T: 'a + Score> LockableScore<'a> for Mutex<T> {
177 type Locked = MutexGuard<'a, T>;
179 fn lock(&'a self) -> MutexGuard<'a, T> {
180 Mutex::lock(self).unwrap()
184 impl<'a, T: 'a + Score> LockableScore<'a> for RefCell<T> {
185 type Locked = RefMut<'a, T>;
187 fn lock(&'a self) -> RefMut<'a, T> {
193 /// A concrete implementation of [`LockableScore`] which supports multi-threading.
194 pub struct MultiThreadedLockableScore<S: Score> {
198 /// A locked `MultiThreadedLockableScore`.
199 pub struct MultiThreadedScoreLock<'a, S: Score>(MutexGuard<'a, S>);
201 impl<'a, T: Score + 'a> Score for MultiThreadedScoreLock<'a, T> {
202 type ScoreParams = <T as Score>::ScoreParams;
203 fn channel_penalty_msat(&self, scid: u64, source: &NodeId, target: &NodeId, usage: ChannelUsage, score_params: &Self::ScoreParams) -> u64 {
204 self.0.channel_penalty_msat(scid, source, target, usage, score_params)
206 fn payment_path_failed(&mut self, path: &Path, short_channel_id: u64) {
207 self.0.payment_path_failed(path, short_channel_id)
209 fn payment_path_successful(&mut self, path: &Path) {
210 self.0.payment_path_successful(path)
212 fn probe_failed(&mut self, path: &Path, short_channel_id: u64) {
213 self.0.probe_failed(path, short_channel_id)
215 fn probe_successful(&mut self, path: &Path) {
216 self.0.probe_successful(path)
220 impl<'a, T: Score + 'a> Writeable for MultiThreadedScoreLock<'a, T> {
221 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
227 impl<'a, T: Score + 'a> LockableScore<'a> for MultiThreadedLockableScore<T> {
228 type Locked = MultiThreadedScoreLock<'a, T>;
230 fn lock(&'a self) -> MultiThreadedScoreLock<'a, T> {
231 MultiThreadedScoreLock(Mutex::lock(&self.score).unwrap())
236 impl<T: Score> Writeable for MultiThreadedLockableScore<T> {
237 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
238 self.lock().write(writer)
243 impl<'a, T: Score + 'a> WriteableScore<'a> for MultiThreadedLockableScore<T> {}
246 impl<T: Score> MultiThreadedLockableScore<T> {
247 /// Creates a new [`MultiThreadedLockableScore`] given an underlying [`Score`].
248 pub fn new(score: T) -> Self {
249 MultiThreadedLockableScore { score: Mutex::new(score) }
254 /// This is not exported to bindings users
255 impl<'a, T: Writeable> Writeable for RefMut<'a, T> {
256 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
257 T::write(&**self, writer)
262 /// This is not exported to bindings users
263 impl<'a, S: Writeable> Writeable for MutexGuard<'a, S> {
264 fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
265 S::write(&**self, writer)
269 /// Proposed use of a channel passed as a parameter to [`Score::channel_penalty_msat`].
270 #[derive(Clone, Copy, Debug, PartialEq)]
271 pub struct ChannelUsage {
272 /// The amount to send through the channel, denominated in millisatoshis.
273 pub amount_msat: u64,
275 /// Total amount, denominated in millisatoshis, already allocated to send through the channel
276 /// as part of a multi-path payment.
277 pub inflight_htlc_msat: u64,
279 /// The effective capacity of the channel.
280 pub effective_capacity: EffectiveCapacity,
284 /// [`Score`] implementation that uses a fixed penalty.
285 pub struct FixedPenaltyScorer {
289 impl FixedPenaltyScorer {
290 /// Creates a new scorer using `penalty_msat`.
291 pub fn with_penalty(penalty_msat: u64) -> Self {
292 Self { penalty_msat }
296 impl Score for FixedPenaltyScorer {
297 type ScoreParams = ();
298 fn channel_penalty_msat(&self, _: u64, _: &NodeId, _: &NodeId, _: ChannelUsage, _score_params: &Self::ScoreParams) -> u64 {
302 fn payment_path_failed(&mut self, _path: &Path, _short_channel_id: u64) {}
304 fn payment_path_successful(&mut self, _path: &Path) {}
306 fn probe_failed(&mut self, _path: &Path, _short_channel_id: u64) {}
308 fn probe_successful(&mut self, _path: &Path) {}
311 impl Writeable for FixedPenaltyScorer {
313 fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
314 write_tlv_fields!(w, {});
319 impl ReadableArgs<u64> for FixedPenaltyScorer {
321 fn read<R: Read>(r: &mut R, penalty_msat: u64) -> Result<Self, DecodeError> {
322 read_tlv_fields!(r, {});
323 Ok(Self { penalty_msat })
327 #[cfg(not(feature = "no-std"))]
328 type ConfiguredTime = std::time::Instant;
329 #[cfg(feature = "no-std")]
330 use crate::util::time::Eternity;
331 #[cfg(feature = "no-std")]
332 type ConfiguredTime = Eternity;
334 /// [`Score`] implementation using channel success probability distributions.
336 /// Channels are tracked with upper and lower liquidity bounds - when an HTLC fails at a channel,
337 /// we learn that the upper-bound on the available liquidity is lower than the amount of the HTLC.
338 /// When a payment is forwarded through a channel (but fails later in the route), we learn the
339 /// lower-bound on the channel's available liquidity must be at least the value of the HTLC.
341 /// These bounds are then used to determine a success probability using the formula from
342 /// *Optimally Reliable & Cheap Payment Flows on the Lightning Network* by Rene Pickhardt
343 /// and Stefan Richter [[1]] (i.e. `(upper_bound - payment_amount) / (upper_bound - lower_bound)`).
345 /// This probability is combined with the [`liquidity_penalty_multiplier_msat`] and
346 /// [`liquidity_penalty_amount_multiplier_msat`] parameters to calculate a concrete penalty in
347 /// milli-satoshis. The penalties, when added across all hops, have the property of being linear in
348 /// terms of the entire path's success probability. This allows the router to directly compare
349 /// penalties for different paths. See the documentation of those parameters for the exact formulas.
351 /// The liquidity bounds are decayed by halving them every [`liquidity_offset_half_life`].
353 /// Further, we track the history of our upper and lower liquidity bounds for each channel,
354 /// allowing us to assign a second penalty (using [`historical_liquidity_penalty_multiplier_msat`]
355 /// and [`historical_liquidity_penalty_amount_multiplier_msat`]) based on the same probability
356 /// formula, but using the history of a channel rather than our latest estimates for the liquidity
361 /// Mixing the `no-std` feature between serialization and deserialization results in undefined
364 /// [1]: https://arxiv.org/abs/2107.05322
365 /// [`liquidity_penalty_multiplier_msat`]: ProbabilisticScoringFeeParameters::liquidity_penalty_multiplier_msat
366 /// [`liquidity_penalty_amount_multiplier_msat`]: ProbabilisticScoringFeeParameters::liquidity_penalty_amount_multiplier_msat
367 /// [`liquidity_offset_half_life`]: ProbabilisticScoringDecayParameters::liquidity_offset_half_life
368 /// [`historical_liquidity_penalty_multiplier_msat`]: ProbabilisticScoringFeeParameters::historical_liquidity_penalty_multiplier_msat
369 /// [`historical_liquidity_penalty_amount_multiplier_msat`]: ProbabilisticScoringFeeParameters::historical_liquidity_penalty_amount_multiplier_msat
370 pub type ProbabilisticScorer<G, L> = ProbabilisticScorerUsingTime::<G, L, ConfiguredTime>;
372 /// Probabilistic [`Score`] implementation.
374 /// This is not exported to bindings users generally all users should use the [`ProbabilisticScorer`] type alias.
375 pub struct ProbabilisticScorerUsingTime<G: Deref<Target = NetworkGraph<L>>, L: Deref, T: Time>
376 where L::Target: Logger {
377 decay_params: ProbabilisticScoringDecayParameters,
380 // TODO: Remove entries of closed channels.
381 channel_liquidities: HashMap<u64, ChannelLiquidity<T>>,
384 /// Parameters for configuring [`ProbabilisticScorer`].
386 /// Used to configure base, liquidity, and amount penalties, the sum of which comprises the channel
387 /// penalty (i.e., the amount in msats willing to be paid to avoid routing through the channel).
389 /// The penalty applied to any channel by the [`ProbabilisticScorer`] is the sum of each of the
392 pub struct ProbabilisticScoringFeeParameters {
393 /// A fixed penalty in msats to apply to each channel.
395 /// Default value: 500 msat
396 pub base_penalty_msat: u64,
398 /// A multiplier used with the payment amount to calculate a fixed penalty applied to each
399 /// channel, in excess of the [`base_penalty_msat`].
401 /// The purpose of the amount penalty is to avoid having fees dominate the channel cost (i.e.,
402 /// fees plus penalty) for large payments. The penalty is computed as the product of this
403 /// multiplier and `2^30`ths of the payment amount.
405 /// ie `base_penalty_amount_multiplier_msat * amount_msat / 2^30`
407 /// Default value: 8,192 msat
409 /// [`base_penalty_msat`]: Self::base_penalty_msat
410 pub base_penalty_amount_multiplier_msat: u64,
412 /// A multiplier used in conjunction with the negative `log10` of the channel's success
413 /// probability for a payment, as determined by our latest estimates of the channel's
414 /// liquidity, to determine the liquidity penalty.
416 /// The penalty is based in part on the knowledge learned from prior successful and unsuccessful
417 /// payments. This knowledge is decayed over time based on [`liquidity_offset_half_life`]. The
418 /// penalty is effectively limited to `2 * liquidity_penalty_multiplier_msat` (corresponding to
419 /// lower bounding the success probability to `0.01`) when the amount falls within the
420 /// uncertainty bounds of the channel liquidity balance. Amounts above the upper bound will
421 /// result in a `u64::max_value` penalty, however.
423 /// `-log10(success_probability) * liquidity_penalty_multiplier_msat`
425 /// Default value: 30,000 msat
427 /// [`liquidity_offset_half_life`]: ProbabilisticScoringDecayParameters::liquidity_offset_half_life
428 pub liquidity_penalty_multiplier_msat: u64,
430 /// A multiplier used in conjunction with a payment amount and the negative `log10` of the
431 /// channel's success probability for the payment, as determined by our latest estimates of the
432 /// channel's liquidity, to determine the amount penalty.
434 /// The purpose of the amount penalty is to avoid having fees dominate the channel cost (i.e.,
435 /// fees plus penalty) for large payments. The penalty is computed as the product of this
436 /// multiplier and `2^20`ths of the payment amount, weighted by the negative `log10` of the
437 /// success probability.
439 /// `-log10(success_probability) * liquidity_penalty_amount_multiplier_msat * amount_msat / 2^20`
441 /// In practice, this means for 0.1 success probability (`-log10(0.1) == 1`) each `2^20`th of
442 /// the amount will result in a penalty of the multiplier. And, as the success probability
443 /// decreases, the negative `log10` weighting will increase dramatically. For higher success
444 /// probabilities, the multiplier will have a decreasing effect as the negative `log10` will
447 /// Default value: 192 msat
448 pub liquidity_penalty_amount_multiplier_msat: u64,
450 /// A multiplier used in conjunction with the negative `log10` of the channel's success
451 /// probability for the payment, as determined based on the history of our estimates of the
452 /// channel's available liquidity, to determine a penalty.
454 /// This penalty is similar to [`liquidity_penalty_multiplier_msat`], however, instead of using
455 /// only our latest estimate for the current liquidity available in the channel, it estimates
456 /// success probability based on the estimated liquidity available in the channel through
457 /// history. Specifically, every time we update our liquidity bounds on a given channel, we
458 /// track which of several buckets those bounds fall into, exponentially decaying the
459 /// probability of each bucket as new samples are added.
461 /// Default value: 10,000 msat
463 /// [`liquidity_penalty_multiplier_msat`]: Self::liquidity_penalty_multiplier_msat
464 pub historical_liquidity_penalty_multiplier_msat: u64,
466 /// A multiplier used in conjunction with the payment amount and the negative `log10` of the
467 /// channel's success probability for the payment, as determined based on the history of our
468 /// estimates of the channel's available liquidity, to determine a penalty.
470 /// The purpose of the amount penalty is to avoid having fees dominate the channel cost for
471 /// large payments. The penalty is computed as the product of this multiplier and the `2^20`ths
472 /// of the payment amount, weighted by the negative `log10` of the success probability.
474 /// This penalty is similar to [`liquidity_penalty_amount_multiplier_msat`], however, instead
475 /// of using only our latest estimate for the current liquidity available in the channel, it
476 /// estimates success probability based on the estimated liquidity available in the channel
477 /// through history. Specifically, every time we update our liquidity bounds on a given
478 /// channel, we track which of several buckets those bounds fall into, exponentially decaying
479 /// the probability of each bucket as new samples are added.
481 /// Default value: 64 msat
483 /// [`liquidity_penalty_amount_multiplier_msat`]: Self::liquidity_penalty_amount_multiplier_msat
484 pub historical_liquidity_penalty_amount_multiplier_msat: u64,
486 /// Manual penalties used for the given nodes. Allows to set a particular penalty for a given
487 /// node. Note that a manual penalty of `u64::max_value()` means the node would not ever be
488 /// considered during path finding.
490 /// This is not exported to bindings users
491 pub manual_node_penalties: HashMap<NodeId, u64>,
493 /// This penalty is applied when `htlc_maximum_msat` is equal to or larger than half of the
494 /// channel's capacity, (ie. htlc_maximum_msat ≥ 0.5 * channel_capacity) which makes us
495 /// prefer nodes with a smaller `htlc_maximum_msat`. We treat such nodes preferentially
496 /// as this makes balance discovery attacks harder to execute, thereby creating an incentive
497 /// to restrict `htlc_maximum_msat` and improve privacy.
499 /// Default value: 250 msat
500 pub anti_probing_penalty_msat: u64,
502 /// This penalty is applied when the amount we're attempting to send over a channel exceeds our
503 /// current estimate of the channel's available liquidity.
505 /// Note that in this case all other penalties, including the
506 /// [`liquidity_penalty_multiplier_msat`] and [`liquidity_penalty_amount_multiplier_msat`]-based
507 /// penalties, as well as the [`base_penalty_msat`] and the [`anti_probing_penalty_msat`], if
508 /// applicable, are still included in the overall penalty.
510 /// If you wish to avoid creating paths with such channels entirely, setting this to a value of
511 /// `u64::max_value()` will guarantee that.
513 /// Default value: 1_0000_0000_000 msat (1 Bitcoin)
515 /// [`liquidity_penalty_multiplier_msat`]: Self::liquidity_penalty_multiplier_msat
516 /// [`liquidity_penalty_amount_multiplier_msat`]: Self::liquidity_penalty_amount_multiplier_msat
517 /// [`base_penalty_msat`]: Self::base_penalty_msat
518 /// [`anti_probing_penalty_msat`]: Self::anti_probing_penalty_msat
519 pub considered_impossible_penalty_msat: u64,
522 /// Parameters for configuring [`ProbabilisticScorer`].
524 /// Used to configure decay parameters that are static throughout the lifetime of the scorer.
525 /// these decay parameters affect the score of the channel penalty and are not changed on a
526 /// per-route penalty cost call.
527 #[derive(Copy, Clone)]
528 pub struct ProbabilisticScoringDecayParameters {
529 /// If we aren't learning any new datapoints for a channel, the historical liquidity bounds
530 /// tracking can simply live on with increasingly stale data. Instead, when a channel has not
531 /// seen a liquidity estimate update for this amount of time, the historical datapoints are
533 /// For an example of historical_no_updates_half_life being used see [`historical_estimated_channel_liquidity_probabilities`]
535 /// Note that after 16 or more half lives all historical data will be completely gone.
537 /// Default value: 14 days
539 /// [`historical_estimated_channel_liquidity_probabilities`]: ProbabilisticScorerUsingTime::historical_estimated_channel_liquidity_probabilities
540 pub historical_no_updates_half_life: Duration,
542 /// Whenever this amount of time elapses since the last update to a channel's liquidity bounds,
543 /// the distance from the bounds to "zero" is cut in half. In other words, the lower-bound on
544 /// the available liquidity is halved and the upper-bound moves half-way to the channel's total
547 /// Because halving the liquidity bounds grows the uncertainty on the channel's liquidity,
548 /// the penalty for an amount within the new bounds may change. See the [`ProbabilisticScorer`]
549 /// struct documentation for more info on the way the liquidity bounds are used.
551 /// For example, if the channel's capacity is 1 million sats, and the current upper and lower
552 /// liquidity bounds are 200,000 sats and 600,000 sats, after this amount of time the upper
553 /// and lower liquidity bounds will be decayed to 100,000 and 800,000 sats.
555 /// Default value: 6 hours
559 /// When built with the `no-std` feature, time will never elapse. Therefore, the channel
560 /// liquidity knowledge will never decay except when the bounds cross.
561 pub liquidity_offset_half_life: Duration,
565 impl ProbabilisticScoringDecayParameters {
566 fn zero_penalty() -> Self {
568 liquidity_offset_half_life: Duration::from_secs(6 * 60 * 60),
569 historical_no_updates_half_life: Duration::from_secs(60 * 60 * 24 * 14),
574 impl Default for ProbabilisticScoringDecayParameters {
575 fn default() -> Self {
577 liquidity_offset_half_life: Duration::from_secs(6 * 60 * 60),
578 historical_no_updates_half_life: Duration::from_secs(60 * 60 * 24 * 14),
582 /// Tracks the historical state of a distribution as a weighted average of how much time was spent
583 /// in each of 8 buckets.
584 #[derive(Clone, Copy)]
585 struct HistoricalBucketRangeTracker {
589 impl HistoricalBucketRangeTracker {
590 fn new() -> Self { Self { buckets: [0; 8] } }
591 fn track_datapoint(&mut self, liquidity_offset_msat: u64, capacity_msat: u64) {
592 // We have 8 leaky buckets for min and max liquidity. Each bucket tracks the amount of time
593 // we spend in each bucket as a 16-bit fixed-point number with a 5 bit fractional part.
595 // Each time we update our liquidity estimate, we add 32 (1.0 in our fixed-point system) to
596 // the buckets for the current min and max liquidity offset positions.
598 // We then decay each bucket by multiplying by 2047/2048 (avoiding dividing by a
599 // non-power-of-two). This ensures we can't actually overflow the u16 - when we get to
600 // 63,457 adding 32 and decaying by 2047/2048 leaves us back at 63,457.
602 // In total, this allows us to track data for the last 8,000 or so payments across a given
605 // These constants are a balance - we try to fit in 2 bytes per bucket to reduce overhead,
606 // and need to balance having more bits in the decimal part (to ensure decay isn't too
607 // non-linear) with having too few bits in the mantissa, causing us to not store very many
610 // The constants were picked experimentally, selecting a decay amount that restricts us
611 // from overflowing buckets without having to cap them manually.
613 // Ensure the bucket index is in the range [0, 7], even if the liquidity offset is zero or
614 // the channel's capacity, though the second should generally never happen.
615 debug_assert!(liquidity_offset_msat <= capacity_msat);
616 let bucket_idx: u8 = (liquidity_offset_msat * 8 / capacity_msat.saturating_add(1))
617 .try_into().unwrap_or(32); // 32 is bogus for 8 buckets, and will be ignored
618 debug_assert!(bucket_idx < 8);
620 for e in self.buckets.iter_mut() {
621 *e = ((*e as u32) * 2047 / 2048) as u16;
623 self.buckets[bucket_idx as usize] = self.buckets[bucket_idx as usize].saturating_add(32);
626 /// Decay all buckets by the given number of half-lives. Used to more aggressively remove old
627 /// datapoints as we receive newer information.
628 fn time_decay_data(&mut self, half_lives: u32) {
629 for e in self.buckets.iter_mut() {
630 *e = e.checked_shr(half_lives).unwrap_or(0);
635 impl_writeable_tlv_based!(HistoricalBucketRangeTracker, { (0, buckets, required) });
637 struct HistoricalMinMaxBuckets<'a> {
638 min_liquidity_offset_history: &'a HistoricalBucketRangeTracker,
639 max_liquidity_offset_history: &'a HistoricalBucketRangeTracker,
642 impl HistoricalMinMaxBuckets<'_> {
644 fn get_decayed_buckets<T: Time>(&self, now: T, last_updated: T, half_life: Duration)
645 -> ([u16; 8], [u16; 8], u32) {
646 let required_decays = now.duration_since(last_updated).as_secs()
647 .checked_div(half_life.as_secs())
648 .map_or(u32::max_value(), |decays| cmp::min(decays, u32::max_value() as u64) as u32);
649 let mut min_buckets = *self.min_liquidity_offset_history;
650 min_buckets.time_decay_data(required_decays);
651 let mut max_buckets = *self.max_liquidity_offset_history;
652 max_buckets.time_decay_data(required_decays);
653 (min_buckets.buckets, max_buckets.buckets, required_decays)
657 fn calculate_success_probability_times_billion<T: Time>(
658 &self, now: T, last_updated: T, half_life: Duration, payment_amt_64th_bucket: u8)
660 // If historical penalties are enabled, calculate the penalty by walking the set of
661 // historical liquidity bucket (min, max) combinations (where min_idx < max_idx) and, for
662 // each, calculate the probability of success given our payment amount, then total the
663 // weighted average probability of success.
665 // We use a sliding scale to decide which point within a given bucket will be compared to
666 // the amount being sent - for lower-bounds, the amount being sent is compared to the lower
667 // edge of the first bucket (i.e. zero), but compared to the upper 7/8ths of the last
668 // bucket (i.e. 9 times the index, or 63), with each bucket in between increasing the
669 // comparison point by 1/64th. For upper-bounds, the same applies, however with an offset
670 // of 1/64th (i.e. starting at one and ending at 64). This avoids failing to assign
671 // penalties to channels at the edges.
673 // If we used the bottom edge of buckets, we'd end up never assigning any penalty at all to
674 // such a channel when sending less than ~0.19% of the channel's capacity (e.g. ~200k sats
675 // for a 1 BTC channel!).
677 // If we used the middle of each bucket we'd never assign any penalty at all when sending
678 // less than 1/16th of a channel's capacity, or 1/8th if we used the top of the bucket.
679 let mut total_valid_points_tracked = 0;
681 // Check if all our buckets are zero, once decayed and treat it as if we had no data. We
682 // don't actually use the decayed buckets, though, as that would lose precision.
683 let (decayed_min_buckets, decayed_max_buckets, required_decays) =
684 self.get_decayed_buckets(now, last_updated, half_life);
685 if decayed_min_buckets.iter().all(|v| *v == 0) || decayed_max_buckets.iter().all(|v| *v == 0) {
689 for (min_idx, min_bucket) in self.min_liquidity_offset_history.buckets.iter().enumerate() {
690 for max_bucket in self.max_liquidity_offset_history.buckets.iter().take(8 - min_idx) {
691 total_valid_points_tracked += (*min_bucket as u64) * (*max_bucket as u64);
694 // If the total valid points is smaller than 1.0 (i.e. 32 in our fixed-point scheme), treat
695 // it as if we were fully decayed.
696 if total_valid_points_tracked.checked_shr(required_decays).unwrap_or(0) < 32*32 {
700 let mut cumulative_success_prob_times_billion = 0;
701 for (min_idx, min_bucket) in self.min_liquidity_offset_history.buckets.iter().enumerate() {
702 for (max_idx, max_bucket) in self.max_liquidity_offset_history.buckets.iter().enumerate().take(8 - min_idx) {
703 let bucket_prob_times_million = (*min_bucket as u64) * (*max_bucket as u64)
704 * 1024 * 1024 / total_valid_points_tracked;
705 let min_64th_bucket = min_idx as u8 * 9;
706 let max_64th_bucket = (7 - max_idx as u8) * 9 + 1;
707 if payment_amt_64th_bucket > max_64th_bucket {
708 // Success probability 0, the payment amount is above the max liquidity
709 } else if payment_amt_64th_bucket <= min_64th_bucket {
710 cumulative_success_prob_times_billion += bucket_prob_times_million * 1024;
712 cumulative_success_prob_times_billion += bucket_prob_times_million *
713 ((max_64th_bucket - payment_amt_64th_bucket) as u64) * 1024 /
714 ((max_64th_bucket - min_64th_bucket) as u64);
719 Some(cumulative_success_prob_times_billion)
723 /// Accounting for channel liquidity balance uncertainty.
725 /// Direction is defined in terms of [`NodeId`] partial ordering, where the source node is the
726 /// first node in the ordering of the channel's counterparties. Thus, swapping the two liquidity
727 /// offset fields gives the opposite direction.
728 struct ChannelLiquidity<T: Time> {
729 /// Lower channel liquidity bound in terms of an offset from zero.
730 min_liquidity_offset_msat: u64,
732 /// Upper channel liquidity bound in terms of an offset from the effective capacity.
733 max_liquidity_offset_msat: u64,
735 /// Time when the liquidity bounds were last modified.
738 min_liquidity_offset_history: HistoricalBucketRangeTracker,
739 max_liquidity_offset_history: HistoricalBucketRangeTracker,
742 /// A snapshot of [`ChannelLiquidity`] in one direction assuming a certain channel capacity and
743 /// decayed with a given half life.
744 struct DirectedChannelLiquidity<L: Deref<Target = u64>, BRT: Deref<Target = HistoricalBucketRangeTracker>, T: Time, U: Deref<Target = T>> {
745 min_liquidity_offset_msat: L,
746 max_liquidity_offset_msat: L,
747 min_liquidity_offset_history: BRT,
748 max_liquidity_offset_history: BRT,
749 inflight_htlc_msat: u64,
753 decay_params: ProbabilisticScoringDecayParameters,
756 impl<G: Deref<Target = NetworkGraph<L>>, L: Deref, T: Time> ProbabilisticScorerUsingTime<G, L, T> where L::Target: Logger {
757 /// Creates a new scorer using the given scoring parameters for sending payments from a node
758 /// through a network graph.
759 pub fn new(decay_params: ProbabilisticScoringDecayParameters, network_graph: G, logger: L) -> Self {
764 channel_liquidities: HashMap::new(),
769 fn with_channel(mut self, short_channel_id: u64, liquidity: ChannelLiquidity<T>) -> Self {
770 assert!(self.channel_liquidities.insert(short_channel_id, liquidity).is_none());
774 /// Dump the contents of this scorer into the configured logger.
776 /// Note that this writes roughly one line per channel for which we have a liquidity estimate,
777 /// which may be a substantial amount of log output.
778 pub fn debug_log_liquidity_stats(&self) {
781 let graph = self.network_graph.read_only();
782 for (scid, liq) in self.channel_liquidities.iter() {
783 if let Some(chan_debug) = graph.channels().get(scid) {
784 let log_direction = |source, target| {
785 if let Some((directed_info, _)) = chan_debug.as_directed_to(target) {
786 let amt = directed_info.effective_capacity().as_msat();
787 let dir_liq = liq.as_directed(source, target, 0, amt, self.decay_params);
789 let buckets = HistoricalMinMaxBuckets {
790 min_liquidity_offset_history: &dir_liq.min_liquidity_offset_history,
791 max_liquidity_offset_history: &dir_liq.max_liquidity_offset_history,
793 let (min_buckets, max_buckets, _) = buckets.get_decayed_buckets(now,
794 *dir_liq.last_updated, self.decay_params.historical_no_updates_half_life);
796 log_debug!(self.logger, core::concat!(
797 "Liquidity from {} to {} via {} is in the range ({}, {}).\n",
798 "\tHistorical min liquidity octile relative probabilities: {} {} {} {} {} {} {} {}\n",
799 "\tHistorical max liquidity octile relative probabilities: {} {} {} {} {} {} {} {}"),
800 source, target, scid, dir_liq.min_liquidity_msat(), dir_liq.max_liquidity_msat(),
801 min_buckets[0], min_buckets[1], min_buckets[2], min_buckets[3],
802 min_buckets[4], min_buckets[5], min_buckets[6], min_buckets[7],
803 // Note that the liquidity buckets are an offset from the edge, so we
804 // inverse the max order to get the probabilities from zero.
805 max_buckets[7], max_buckets[6], max_buckets[5], max_buckets[4],
806 max_buckets[3], max_buckets[2], max_buckets[1], max_buckets[0]);
808 log_debug!(self.logger, "No amount known for SCID {} from {:?} to {:?}", scid, source, target);
812 log_direction(&chan_debug.node_one, &chan_debug.node_two);
813 log_direction(&chan_debug.node_two, &chan_debug.node_one);
815 log_debug!(self.logger, "No network graph entry for SCID {}", scid);
820 /// Query the estimated minimum and maximum liquidity available for sending a payment over the
821 /// channel with `scid` towards the given `target` node.
822 pub fn estimated_channel_liquidity_range(&self, scid: u64, target: &NodeId) -> Option<(u64, u64)> {
823 let graph = self.network_graph.read_only();
825 if let Some(chan) = graph.channels().get(&scid) {
826 if let Some(liq) = self.channel_liquidities.get(&scid) {
827 if let Some((directed_info, source)) = chan.as_directed_to(target) {
828 let amt = directed_info.effective_capacity().as_msat();
829 let dir_liq = liq.as_directed(source, target, 0, amt, self.decay_params);
830 return Some((dir_liq.min_liquidity_msat(), dir_liq.max_liquidity_msat()));
837 /// Query the historical estimated minimum and maximum liquidity available for sending a
838 /// payment over the channel with `scid` towards the given `target` node.
840 /// Returns two sets of 8 buckets. The first set describes the octiles for lower-bound
841 /// liquidity estimates, the second set describes the octiles for upper-bound liquidity
842 /// estimates. Each bucket describes the relative frequency at which we've seen a liquidity
843 /// bound in the octile relative to the channel's total capacity, on an arbitrary scale.
844 /// Because the values are slowly decayed, more recent data points are weighted more heavily
845 /// than older datapoints.
847 /// When scoring, the estimated probability that an upper-/lower-bound lies in a given octile
848 /// relative to the channel's total capacity is calculated by dividing that bucket's value with
849 /// the total of all buckets for the given bound.
851 /// For example, a value of `[0, 0, 0, 0, 0, 0, 32]` indicates that we believe the probability
852 /// of a bound being in the top octile to be 100%, and have never (recently) seen it in any
853 /// other octiles. A value of `[31, 0, 0, 0, 0, 0, 0, 32]` indicates we've seen the bound being
854 /// both in the top and bottom octile, and roughly with similar (recent) frequency.
856 /// Because the datapoints are decayed slowly over time, values will eventually return to
857 /// `Some(([0; 8], [0; 8]))`.
858 pub fn historical_estimated_channel_liquidity_probabilities(&self, scid: u64, target: &NodeId)
859 -> Option<([u16; 8], [u16; 8])> {
860 let graph = self.network_graph.read_only();
862 if let Some(chan) = graph.channels().get(&scid) {
863 if let Some(liq) = self.channel_liquidities.get(&scid) {
864 if let Some((directed_info, source)) = chan.as_directed_to(target) {
865 let amt = directed_info.effective_capacity().as_msat();
866 let dir_liq = liq.as_directed(source, target, 0, amt, self.decay_params);
868 let buckets = HistoricalMinMaxBuckets {
869 min_liquidity_offset_history: &dir_liq.min_liquidity_offset_history,
870 max_liquidity_offset_history: &dir_liq.max_liquidity_offset_history,
872 let (min_buckets, mut max_buckets, _) = buckets.get_decayed_buckets(T::now(),
873 *dir_liq.last_updated, self.decay_params.historical_no_updates_half_life);
874 // Note that the liquidity buckets are an offset from the edge, so we inverse
875 // the max order to get the probabilities from zero.
876 max_buckets.reverse();
877 return Some((min_buckets, max_buckets));
885 impl ProbabilisticScoringFeeParameters {
887 fn zero_penalty() -> Self {
889 base_penalty_msat: 0,
890 base_penalty_amount_multiplier_msat: 0,
891 liquidity_penalty_multiplier_msat: 0,
892 liquidity_penalty_amount_multiplier_msat: 0,
893 historical_liquidity_penalty_multiplier_msat: 0,
894 historical_liquidity_penalty_amount_multiplier_msat: 0,
895 manual_node_penalties: HashMap::new(),
896 anti_probing_penalty_msat: 0,
897 considered_impossible_penalty_msat: 0,
901 /// Marks the node with the given `node_id` as banned, i.e.,
902 /// it will be avoided during path finding.
903 pub fn add_banned(&mut self, node_id: &NodeId) {
904 self.manual_node_penalties.insert(*node_id, u64::max_value());
907 /// Marks all nodes in the given list as banned, i.e.,
908 /// they will be avoided during path finding.
909 pub fn add_banned_from_list(&mut self, node_ids: Vec<NodeId>) {
911 self.manual_node_penalties.insert(id, u64::max_value());
915 /// Removes the node with the given `node_id` from the list of nodes to avoid.
916 pub fn remove_banned(&mut self, node_id: &NodeId) {
917 self.manual_node_penalties.remove(node_id);
920 /// Sets a manual penalty for the given node.
921 pub fn set_manual_penalty(&mut self, node_id: &NodeId, penalty: u64) {
922 self.manual_node_penalties.insert(*node_id, penalty);
925 /// Removes the node with the given `node_id` from the list of manual penalties.
926 pub fn remove_manual_penalty(&mut self, node_id: &NodeId) {
927 self.manual_node_penalties.remove(node_id);
930 /// Clears the list of manual penalties that are applied during path finding.
931 pub fn clear_manual_penalties(&mut self) {
932 self.manual_node_penalties = HashMap::new();
936 impl Default for ProbabilisticScoringFeeParameters {
937 fn default() -> Self {
939 base_penalty_msat: 500,
940 base_penalty_amount_multiplier_msat: 8192,
941 liquidity_penalty_multiplier_msat: 30_000,
942 liquidity_penalty_amount_multiplier_msat: 192,
943 manual_node_penalties: HashMap::new(),
944 anti_probing_penalty_msat: 250,
945 considered_impossible_penalty_msat: 1_0000_0000_000,
946 historical_liquidity_penalty_multiplier_msat: 10_000,
947 historical_liquidity_penalty_amount_multiplier_msat: 64,
952 impl<T: Time> ChannelLiquidity<T> {
956 min_liquidity_offset_msat: 0,
957 max_liquidity_offset_msat: 0,
958 min_liquidity_offset_history: HistoricalBucketRangeTracker::new(),
959 max_liquidity_offset_history: HistoricalBucketRangeTracker::new(),
960 last_updated: T::now(),
964 /// Returns a view of the channel liquidity directed from `source` to `target` assuming
967 &self, source: &NodeId, target: &NodeId, inflight_htlc_msat: u64, capacity_msat: u64, decay_params: ProbabilisticScoringDecayParameters
968 ) -> DirectedChannelLiquidity<&u64, &HistoricalBucketRangeTracker, T, &T> {
969 let (min_liquidity_offset_msat, max_liquidity_offset_msat, min_liquidity_offset_history, max_liquidity_offset_history) =
971 (&self.min_liquidity_offset_msat, &self.max_liquidity_offset_msat,
972 &self.min_liquidity_offset_history, &self.max_liquidity_offset_history)
974 (&self.max_liquidity_offset_msat, &self.min_liquidity_offset_msat,
975 &self.max_liquidity_offset_history, &self.min_liquidity_offset_history)
978 DirectedChannelLiquidity {
979 min_liquidity_offset_msat,
980 max_liquidity_offset_msat,
981 min_liquidity_offset_history,
982 max_liquidity_offset_history,
985 last_updated: &self.last_updated,
987 decay_params: decay_params,
991 /// Returns a mutable view of the channel liquidity directed from `source` to `target` assuming
994 &mut self, source: &NodeId, target: &NodeId, inflight_htlc_msat: u64, capacity_msat: u64, decay_params: ProbabilisticScoringDecayParameters
995 ) -> DirectedChannelLiquidity<&mut u64, &mut HistoricalBucketRangeTracker, T, &mut T> {
996 let (min_liquidity_offset_msat, max_liquidity_offset_msat, min_liquidity_offset_history, max_liquidity_offset_history) =
998 (&mut self.min_liquidity_offset_msat, &mut self.max_liquidity_offset_msat,
999 &mut self.min_liquidity_offset_history, &mut self.max_liquidity_offset_history)
1001 (&mut self.max_liquidity_offset_msat, &mut self.min_liquidity_offset_msat,
1002 &mut self.max_liquidity_offset_history, &mut self.min_liquidity_offset_history)
1005 DirectedChannelLiquidity {
1006 min_liquidity_offset_msat,
1007 max_liquidity_offset_msat,
1008 min_liquidity_offset_history,
1009 max_liquidity_offset_history,
1012 last_updated: &mut self.last_updated,
1014 decay_params: decay_params,
1019 /// Bounds `-log10` to avoid excessive liquidity penalties for payments with low success
1021 const NEGATIVE_LOG10_UPPER_BOUND: u64 = 2;
1023 /// The rough cutoff at which our precision falls off and we should stop bothering to try to log a
1024 /// ratio, as X in 1/X.
1025 const PRECISION_LOWER_BOUND_DENOMINATOR: u64 = approx::LOWER_BITS_BOUND;
1027 /// The divisor used when computing the amount penalty.
1028 const AMOUNT_PENALTY_DIVISOR: u64 = 1 << 20;
1029 const BASE_AMOUNT_PENALTY_DIVISOR: u64 = 1 << 30;
1031 impl<L: Deref<Target = u64>, BRT: Deref<Target = HistoricalBucketRangeTracker>, T: Time, U: Deref<Target = T>> DirectedChannelLiquidity< L, BRT, T, U> {
1032 /// Returns a liquidity penalty for routing the given HTLC `amount_msat` through the channel in
1034 fn penalty_msat(&self, amount_msat: u64, score_params: &ProbabilisticScoringFeeParameters) -> u64 {
1035 let max_liquidity_msat = self.max_liquidity_msat();
1036 let min_liquidity_msat = core::cmp::min(self.min_liquidity_msat(), max_liquidity_msat);
1038 let mut res = if amount_msat <= min_liquidity_msat {
1040 } else if amount_msat >= max_liquidity_msat {
1041 // Equivalent to hitting the else clause below with the amount equal to the effective
1042 // capacity and without any certainty on the liquidity upper bound, plus the
1043 // impossibility penalty.
1044 let negative_log10_times_2048 = NEGATIVE_LOG10_UPPER_BOUND * 2048;
1045 Self::combined_penalty_msat(amount_msat, negative_log10_times_2048,
1046 score_params.liquidity_penalty_multiplier_msat,
1047 score_params.liquidity_penalty_amount_multiplier_msat)
1048 .saturating_add(score_params.considered_impossible_penalty_msat)
1050 let numerator = (max_liquidity_msat - amount_msat).saturating_add(1);
1051 let denominator = (max_liquidity_msat - min_liquidity_msat).saturating_add(1);
1052 if amount_msat - min_liquidity_msat < denominator / PRECISION_LOWER_BOUND_DENOMINATOR {
1053 // If the failure probability is < 1.5625% (as 1 - numerator/denominator < 1/64),
1054 // don't bother trying to use the log approximation as it gets too noisy to be
1055 // particularly helpful, instead just round down to 0.
1058 let negative_log10_times_2048 =
1059 approx::negative_log10_times_2048(numerator, denominator);
1060 Self::combined_penalty_msat(amount_msat, negative_log10_times_2048,
1061 score_params.liquidity_penalty_multiplier_msat,
1062 score_params.liquidity_penalty_amount_multiplier_msat)
1066 if score_params.historical_liquidity_penalty_multiplier_msat != 0 ||
1067 score_params.historical_liquidity_penalty_amount_multiplier_msat != 0 {
1068 let payment_amt_64th_bucket = if amount_msat < u64::max_value() / 64 {
1069 amount_msat * 64 / self.capacity_msat.saturating_add(1)
1071 // Only use 128-bit arithmetic when multiplication will overflow to avoid 128-bit
1072 // division. This branch should only be hit in fuzz testing since the amount would
1073 // need to be over 2.88 million BTC in practice.
1074 ((amount_msat as u128) * 64 / (self.capacity_msat as u128).saturating_add(1))
1075 .try_into().unwrap_or(65)
1077 #[cfg(not(fuzzing))]
1078 debug_assert!(payment_amt_64th_bucket <= 64);
1079 if payment_amt_64th_bucket > 64 { return res; }
1081 let buckets = HistoricalMinMaxBuckets {
1082 min_liquidity_offset_history: &self.min_liquidity_offset_history,
1083 max_liquidity_offset_history: &self.max_liquidity_offset_history,
1085 if let Some(cumulative_success_prob_times_billion) = buckets
1086 .calculate_success_probability_times_billion(self.now, *self.last_updated,
1087 self.decay_params.historical_no_updates_half_life, payment_amt_64th_bucket as u8)
1089 let historical_negative_log10_times_2048 = approx::negative_log10_times_2048(cumulative_success_prob_times_billion + 1, 1024 * 1024 * 1024);
1090 res = res.saturating_add(Self::combined_penalty_msat(amount_msat,
1091 historical_negative_log10_times_2048, score_params.historical_liquidity_penalty_multiplier_msat,
1092 score_params.historical_liquidity_penalty_amount_multiplier_msat));
1094 // If we don't have any valid points (or, once decayed, we have less than a full
1095 // point), redo the non-historical calculation with no liquidity bounds tracked and
1096 // the historical penalty multipliers.
1097 let available_capacity = self.available_capacity();
1098 let numerator = available_capacity.saturating_sub(amount_msat).saturating_add(1);
1099 let denominator = available_capacity.saturating_add(1);
1100 let negative_log10_times_2048 =
1101 approx::negative_log10_times_2048(numerator, denominator);
1102 res = res.saturating_add(Self::combined_penalty_msat(amount_msat, negative_log10_times_2048,
1103 score_params.historical_liquidity_penalty_multiplier_msat,
1104 score_params.historical_liquidity_penalty_amount_multiplier_msat));
1111 /// Computes the liquidity penalty from the penalty multipliers.
1113 fn combined_penalty_msat(amount_msat: u64, negative_log10_times_2048: u64,
1114 liquidity_penalty_multiplier_msat: u64, liquidity_penalty_amount_multiplier_msat: u64,
1116 let liquidity_penalty_msat = {
1117 // Upper bound the liquidity penalty to ensure some channel is selected.
1118 let multiplier_msat = liquidity_penalty_multiplier_msat;
1119 let max_penalty_msat = multiplier_msat.saturating_mul(NEGATIVE_LOG10_UPPER_BOUND);
1120 (negative_log10_times_2048.saturating_mul(multiplier_msat) / 2048).min(max_penalty_msat)
1122 let amount_penalty_msat = negative_log10_times_2048
1123 .saturating_mul(liquidity_penalty_amount_multiplier_msat)
1124 .saturating_mul(amount_msat) / 2048 / AMOUNT_PENALTY_DIVISOR;
1126 liquidity_penalty_msat.saturating_add(amount_penalty_msat)
1129 /// Returns the lower bound of the channel liquidity balance in this direction.
1130 fn min_liquidity_msat(&self) -> u64 {
1131 self.decayed_offset_msat(*self.min_liquidity_offset_msat)
1134 /// Returns the upper bound of the channel liquidity balance in this direction.
1135 fn max_liquidity_msat(&self) -> u64 {
1136 self.available_capacity()
1137 .saturating_sub(self.decayed_offset_msat(*self.max_liquidity_offset_msat))
1140 /// Returns the capacity minus the in-flight HTLCs in this direction.
1141 fn available_capacity(&self) -> u64 {
1142 self.capacity_msat.saturating_sub(self.inflight_htlc_msat)
1145 fn decayed_offset_msat(&self, offset_msat: u64) -> u64 {
1146 self.now.duration_since(*self.last_updated).as_secs()
1147 .checked_div(self.decay_params.liquidity_offset_half_life.as_secs())
1148 .and_then(|decays| offset_msat.checked_shr(decays as u32))
1153 impl<L: DerefMut<Target = u64>, BRT: DerefMut<Target = HistoricalBucketRangeTracker>, T: Time, U: DerefMut<Target = T>> DirectedChannelLiquidity<L, BRT, T, U> {
1154 /// Adjusts the channel liquidity balance bounds when failing to route `amount_msat`.
1155 fn failed_at_channel<Log: Deref>(&mut self, amount_msat: u64, chan_descr: fmt::Arguments, logger: &Log) where Log::Target: Logger {
1156 let existing_max_msat = self.max_liquidity_msat();
1157 if amount_msat < existing_max_msat {
1158 log_debug!(logger, "Setting max liquidity of {} from {} to {}", chan_descr, existing_max_msat, amount_msat);
1159 self.set_max_liquidity_msat(amount_msat);
1161 log_trace!(logger, "Max liquidity of {} is {} (already less than or equal to {})",
1162 chan_descr, existing_max_msat, amount_msat);
1164 self.update_history_buckets();
1167 /// Adjusts the channel liquidity balance bounds when failing to route `amount_msat` downstream.
1168 fn failed_downstream<Log: Deref>(&mut self, amount_msat: u64, chan_descr: fmt::Arguments, logger: &Log) where Log::Target: Logger {
1169 let existing_min_msat = self.min_liquidity_msat();
1170 if amount_msat > existing_min_msat {
1171 log_debug!(logger, "Setting min liquidity of {} from {} to {}", existing_min_msat, chan_descr, amount_msat);
1172 self.set_min_liquidity_msat(amount_msat);
1174 log_trace!(logger, "Min liquidity of {} is {} (already greater than or equal to {})",
1175 chan_descr, existing_min_msat, amount_msat);
1177 self.update_history_buckets();
1180 /// Adjusts the channel liquidity balance bounds when successfully routing `amount_msat`.
1181 fn successful<Log: Deref>(&mut self, amount_msat: u64, chan_descr: fmt::Arguments, logger: &Log) where Log::Target: Logger {
1182 let max_liquidity_msat = self.max_liquidity_msat().checked_sub(amount_msat).unwrap_or(0);
1183 log_debug!(logger, "Subtracting {} from max liquidity of {} (setting it to {})", amount_msat, chan_descr, max_liquidity_msat);
1184 self.set_max_liquidity_msat(max_liquidity_msat);
1185 self.update_history_buckets();
1188 fn update_history_buckets(&mut self) {
1189 let half_lives = self.now.duration_since(*self.last_updated).as_secs()
1190 .checked_div(self.decay_params.historical_no_updates_half_life.as_secs())
1191 .map(|v| v.try_into().unwrap_or(u32::max_value())).unwrap_or(u32::max_value());
1192 self.min_liquidity_offset_history.time_decay_data(half_lives);
1193 self.max_liquidity_offset_history.time_decay_data(half_lives);
1195 let min_liquidity_offset_msat = self.decayed_offset_msat(*self.min_liquidity_offset_msat);
1196 self.min_liquidity_offset_history.track_datapoint(
1197 min_liquidity_offset_msat, self.capacity_msat
1199 let max_liquidity_offset_msat = self.decayed_offset_msat(*self.max_liquidity_offset_msat);
1200 self.max_liquidity_offset_history.track_datapoint(
1201 max_liquidity_offset_msat, self.capacity_msat
1205 /// Adjusts the lower bound of the channel liquidity balance in this direction.
1206 fn set_min_liquidity_msat(&mut self, amount_msat: u64) {
1207 *self.min_liquidity_offset_msat = amount_msat;
1208 *self.max_liquidity_offset_msat = if amount_msat > self.max_liquidity_msat() {
1211 self.decayed_offset_msat(*self.max_liquidity_offset_msat)
1213 *self.last_updated = self.now;
1216 /// Adjusts the upper bound of the channel liquidity balance in this direction.
1217 fn set_max_liquidity_msat(&mut self, amount_msat: u64) {
1218 *self.max_liquidity_offset_msat = self.capacity_msat.checked_sub(amount_msat).unwrap_or(0);
1219 *self.min_liquidity_offset_msat = if amount_msat < self.min_liquidity_msat() {
1222 self.decayed_offset_msat(*self.min_liquidity_offset_msat)
1224 *self.last_updated = self.now;
1228 impl<G: Deref<Target = NetworkGraph<L>>, L: Deref, T: Time> Score for ProbabilisticScorerUsingTime<G, L, T> where L::Target: Logger {
1229 type ScoreParams = ProbabilisticScoringFeeParameters;
1230 fn channel_penalty_msat(
1231 &self, short_channel_id: u64, source: &NodeId, target: &NodeId, usage: ChannelUsage, score_params: &ProbabilisticScoringFeeParameters
1233 if let Some(penalty) = score_params.manual_node_penalties.get(target) {
1237 let base_penalty_msat = score_params.base_penalty_msat.saturating_add(
1238 score_params.base_penalty_amount_multiplier_msat
1239 .saturating_mul(usage.amount_msat) / BASE_AMOUNT_PENALTY_DIVISOR);
1241 let mut anti_probing_penalty_msat = 0;
1242 match usage.effective_capacity {
1243 EffectiveCapacity::ExactLiquidity { liquidity_msat } => {
1244 if usage.amount_msat > liquidity_msat {
1245 return u64::max_value();
1247 return base_penalty_msat;
1250 EffectiveCapacity::Total { capacity_msat, htlc_maximum_msat } => {
1251 if htlc_maximum_msat >= capacity_msat/2 {
1252 anti_probing_penalty_msat = score_params.anti_probing_penalty_msat;
1258 let amount_msat = usage.amount_msat;
1259 let capacity_msat = usage.effective_capacity.as_msat();
1260 let inflight_htlc_msat = usage.inflight_htlc_msat;
1261 self.channel_liquidities
1262 .get(&short_channel_id)
1263 .unwrap_or(&ChannelLiquidity::new())
1264 .as_directed(source, target, inflight_htlc_msat, capacity_msat, self.decay_params)
1265 .penalty_msat(amount_msat, score_params)
1266 .saturating_add(anti_probing_penalty_msat)
1267 .saturating_add(base_penalty_msat)
1270 fn payment_path_failed(&mut self, path: &Path, short_channel_id: u64) {
1271 let amount_msat = path.final_value_msat();
1272 log_trace!(self.logger, "Scoring path through to SCID {} as having failed at {} msat", short_channel_id, amount_msat);
1273 let network_graph = self.network_graph.read_only();
1274 for (hop_idx, hop) in path.hops.iter().enumerate() {
1275 let target = NodeId::from_pubkey(&hop.pubkey);
1276 let channel_directed_from_source = network_graph.channels()
1277 .get(&hop.short_channel_id)
1278 .and_then(|channel| channel.as_directed_to(&target));
1280 let at_failed_channel = hop.short_channel_id == short_channel_id;
1281 if at_failed_channel && hop_idx == 0 {
1282 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);
1285 // Only score announced channels.
1286 if let Some((channel, source)) = channel_directed_from_source {
1287 let capacity_msat = channel.effective_capacity().as_msat();
1288 if at_failed_channel {
1289 self.channel_liquidities
1290 .entry(hop.short_channel_id)
1291 .or_insert_with(ChannelLiquidity::new)
1292 .as_directed_mut(source, &target, 0, capacity_msat, self.decay_params)
1293 .failed_at_channel(amount_msat, format_args!("SCID {}, towards {:?}", hop.short_channel_id, target), &self.logger);
1295 self.channel_liquidities
1296 .entry(hop.short_channel_id)
1297 .or_insert_with(ChannelLiquidity::new)
1298 .as_directed_mut(source, &target, 0, capacity_msat, self.decay_params)
1299 .failed_downstream(amount_msat, format_args!("SCID {}, towards {:?}", hop.short_channel_id, target), &self.logger);
1302 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).",
1303 hop.short_channel_id);
1305 if at_failed_channel { break; }
1309 fn payment_path_successful(&mut self, path: &Path) {
1310 let amount_msat = path.final_value_msat();
1311 log_trace!(self.logger, "Scoring path through SCID {} as having succeeded at {} msat.",
1312 path.hops.split_last().map(|(hop, _)| hop.short_channel_id).unwrap_or(0), amount_msat);
1313 let network_graph = self.network_graph.read_only();
1314 for hop in &path.hops {
1315 let target = NodeId::from_pubkey(&hop.pubkey);
1316 let channel_directed_from_source = network_graph.channels()
1317 .get(&hop.short_channel_id)
1318 .and_then(|channel| channel.as_directed_to(&target));
1320 // Only score announced channels.
1321 if let Some((channel, source)) = channel_directed_from_source {
1322 let capacity_msat = channel.effective_capacity().as_msat();
1323 self.channel_liquidities
1324 .entry(hop.short_channel_id)
1325 .or_insert_with(ChannelLiquidity::new)
1326 .as_directed_mut(source, &target, 0, capacity_msat, self.decay_params)
1327 .successful(amount_msat, format_args!("SCID {}, towards {:?}", hop.short_channel_id, target), &self.logger);
1329 log_debug!(self.logger, "Not able to learn for channel with SCID {} as we do not have graph info for it (likely a route-hint last-hop).",
1330 hop.short_channel_id);
1335 fn probe_failed(&mut self, path: &Path, short_channel_id: u64) {
1336 self.payment_path_failed(path, short_channel_id)
1339 fn probe_successful(&mut self, path: &Path) {
1340 self.payment_path_failed(path, u64::max_value())
1345 const BITS: u32 = 64;
1346 const HIGHEST_BIT: u32 = BITS - 1;
1347 const LOWER_BITS: u32 = 6;
1348 pub(super) const LOWER_BITS_BOUND: u64 = 1 << LOWER_BITS;
1349 const LOWER_BITMASK: u64 = (1 << LOWER_BITS) - 1;
1351 /// Look-up table for `log10(x) * 2048` where row `i` is used for each `x` having `i` as the
1352 /// most significant bit. The next 4 bits of `x`, if applicable, are used for the second index.
1353 const LOG10_TIMES_2048: [[u16; (LOWER_BITS_BOUND) as usize]; BITS as usize] = [
1354 [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
1355 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
1356 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
1357 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
1358 [617, 617, 617, 617, 617, 617, 617, 617, 617, 617, 617, 617, 617, 617, 617, 617,
1359 617, 617, 617, 617, 617, 617, 617, 617, 617, 617, 617, 617, 617, 617, 617, 617,
1360 977, 977, 977, 977, 977, 977, 977, 977, 977, 977, 977, 977, 977, 977, 977, 977,
1361 977, 977, 977, 977, 977, 977, 977, 977, 977, 977, 977, 977, 977, 977, 977, 977],
1362 [1233, 1233, 1233, 1233, 1233, 1233, 1233, 1233, 1233, 1233, 1233, 1233, 1233, 1233, 1233, 1233,
1363 1431, 1431, 1431, 1431, 1431, 1431, 1431, 1431, 1431, 1431, 1431, 1431, 1431, 1431, 1431, 1431,
1364 1594, 1594, 1594, 1594, 1594, 1594, 1594, 1594, 1594, 1594, 1594, 1594, 1594, 1594, 1594, 1594,
1365 1731, 1731, 1731, 1731, 1731, 1731, 1731, 1731, 1731, 1731, 1731, 1731, 1731, 1731, 1731, 1731],
1366 [1850, 1850, 1850, 1850, 1850, 1850, 1850, 1850, 1954, 1954, 1954, 1954, 1954, 1954, 1954, 1954,
1367 2048, 2048, 2048, 2048, 2048, 2048, 2048, 2048, 2133, 2133, 2133, 2133, 2133, 2133, 2133, 2133,
1368 2210, 2210, 2210, 2210, 2210, 2210, 2210, 2210, 2281, 2281, 2281, 2281, 2281, 2281, 2281, 2281,
1369 2347, 2347, 2347, 2347, 2347, 2347, 2347, 2347, 2409, 2409, 2409, 2409, 2409, 2409, 2409, 2409],
1370 [2466, 2466, 2466, 2466, 2520, 2520, 2520, 2520, 2571, 2571, 2571, 2571, 2619, 2619, 2619, 2619,
1371 2665, 2665, 2665, 2665, 2708, 2708, 2708, 2708, 2749, 2749, 2749, 2749, 2789, 2789, 2789, 2789,
1372 2827, 2827, 2827, 2827, 2863, 2863, 2863, 2863, 2898, 2898, 2898, 2898, 2931, 2931, 2931, 2931,
1373 2964, 2964, 2964, 2964, 2995, 2995, 2995, 2995, 3025, 3025, 3025, 3025, 3054, 3054, 3054, 3054],
1374 [3083, 3083, 3110, 3110, 3136, 3136, 3162, 3162, 3187, 3187, 3212, 3212, 3235, 3235, 3259, 3259,
1375 3281, 3281, 3303, 3303, 3324, 3324, 3345, 3345, 3366, 3366, 3386, 3386, 3405, 3405, 3424, 3424,
1376 3443, 3443, 3462, 3462, 3479, 3479, 3497, 3497, 3514, 3514, 3531, 3531, 3548, 3548, 3564, 3564,
1377 3580, 3580, 3596, 3596, 3612, 3612, 3627, 3627, 3642, 3642, 3656, 3656, 3671, 3671, 3685, 3685],
1378 [3699, 3713, 3726, 3740, 3753, 3766, 3779, 3791, 3804, 3816, 3828, 3840, 3852, 3864, 3875, 3886,
1379 3898, 3909, 3919, 3930, 3941, 3951, 3962, 3972, 3982, 3992, 4002, 4012, 4022, 4031, 4041, 4050,
1380 4060, 4069, 4078, 4087, 4096, 4105, 4114, 4122, 4131, 4139, 4148, 4156, 4164, 4173, 4181, 4189,
1381 4197, 4205, 4213, 4220, 4228, 4236, 4243, 4251, 4258, 4266, 4273, 4280, 4287, 4294, 4302, 4309],
1382 [4316, 4329, 4343, 4356, 4369, 4382, 4395, 4408, 4420, 4433, 4445, 4457, 4468, 4480, 4492, 4503,
1383 4514, 4525, 4536, 4547, 4557, 4568, 4578, 4589, 4599, 4609, 4619, 4629, 4638, 4648, 4657, 4667,
1384 4676, 4685, 4695, 4704, 4713, 4721, 4730, 4739, 4747, 4756, 4764, 4773, 4781, 4789, 4797, 4805,
1385 4813, 4821, 4829, 4837, 4845, 4852, 4860, 4867, 4875, 4882, 4889, 4897, 4904, 4911, 4918, 4925],
1386 [4932, 4946, 4959, 4973, 4986, 4999, 5012, 5024, 5037, 5049, 5061, 5073, 5085, 5097, 5108, 5119,
1387 5131, 5142, 5153, 5163, 5174, 5184, 5195, 5205, 5215, 5225, 5235, 5245, 5255, 5264, 5274, 5283,
1388 5293, 5302, 5311, 5320, 5329, 5338, 5347, 5355, 5364, 5372, 5381, 5389, 5397, 5406, 5414, 5422,
1389 5430, 5438, 5446, 5453, 5461, 5469, 5476, 5484, 5491, 5499, 5506, 5513, 5520, 5527, 5535, 5542],
1390 [5549, 5562, 5576, 5589, 5603, 5615, 5628, 5641, 5653, 5666, 5678, 5690, 5701, 5713, 5725, 5736,
1391 5747, 5758, 5769, 5780, 5790, 5801, 5811, 5822, 5832, 5842, 5852, 5862, 5871, 5881, 5890, 5900,
1392 5909, 5918, 5928, 5937, 5946, 5954, 5963, 5972, 5980, 5989, 5997, 6006, 6014, 6022, 6030, 6038,
1393 6046, 6054, 6062, 6070, 6078, 6085, 6093, 6100, 6108, 6115, 6122, 6130, 6137, 6144, 6151, 6158],
1394 [6165, 6179, 6192, 6206, 6219, 6232, 6245, 6257, 6270, 6282, 6294, 6306, 6318, 6330, 6341, 6352,
1395 6364, 6375, 6386, 6396, 6407, 6417, 6428, 6438, 6448, 6458, 6468, 6478, 6488, 6497, 6507, 6516,
1396 6526, 6535, 6544, 6553, 6562, 6571, 6580, 6588, 6597, 6605, 6614, 6622, 6630, 6639, 6647, 6655,
1397 6663, 6671, 6679, 6686, 6694, 6702, 6709, 6717, 6724, 6732, 6739, 6746, 6753, 6761, 6768, 6775],
1398 [6782, 6795, 6809, 6822, 6836, 6849, 6861, 6874, 6886, 6899, 6911, 6923, 6934, 6946, 6958, 6969,
1399 6980, 6991, 7002, 7013, 7023, 7034, 7044, 7055, 7065, 7075, 7085, 7095, 7104, 7114, 7124, 7133,
1400 7142, 7151, 7161, 7170, 7179, 7187, 7196, 7205, 7213, 7222, 7230, 7239, 7247, 7255, 7263, 7271,
1401 7279, 7287, 7295, 7303, 7311, 7318, 7326, 7333, 7341, 7348, 7355, 7363, 7370, 7377, 7384, 7391],
1402 [7398, 7412, 7425, 7439, 7452, 7465, 7478, 7490, 7503, 7515, 7527, 7539, 7551, 7563, 7574, 7585,
1403 7597, 7608, 7619, 7629, 7640, 7651, 7661, 7671, 7681, 7691, 7701, 7711, 7721, 7731, 7740, 7749,
1404 7759, 7768, 7777, 7786, 7795, 7804, 7813, 7821, 7830, 7838, 7847, 7855, 7864, 7872, 7880, 7888,
1405 7896, 7904, 7912, 7919, 7927, 7935, 7942, 7950, 7957, 7965, 7972, 7979, 7986, 7994, 8001, 8008],
1406 [8015, 8028, 8042, 8055, 8069, 8082, 8094, 8107, 8119, 8132, 8144, 8156, 8167, 8179, 8191, 8202,
1407 8213, 8224, 8235, 8246, 8256, 8267, 8277, 8288, 8298, 8308, 8318, 8328, 8337, 8347, 8357, 8366,
1408 8375, 8384, 8394, 8403, 8412, 8420, 8429, 8438, 8446, 8455, 8463, 8472, 8480, 8488, 8496, 8504,
1409 8512, 8520, 8528, 8536, 8544, 8551, 8559, 8566, 8574, 8581, 8588, 8596, 8603, 8610, 8617, 8624],
1410 [8631, 8645, 8659, 8672, 8685, 8698, 8711, 8723, 8736, 8748, 8760, 8772, 8784, 8796, 8807, 8818,
1411 8830, 8841, 8852, 8862, 8873, 8884, 8894, 8904, 8914, 8924, 8934, 8944, 8954, 8964, 8973, 8982,
1412 8992, 9001, 9010, 9019, 9028, 9037, 9046, 9054, 9063, 9071, 9080, 9088, 9097, 9105, 9113, 9121,
1413 9129, 9137, 9145, 9152, 9160, 9168, 9175, 9183, 9190, 9198, 9205, 9212, 9219, 9227, 9234, 9241],
1414 [9248, 9261, 9275, 9288, 9302, 9315, 9327, 9340, 9352, 9365, 9377, 9389, 9400, 9412, 9424, 9435,
1415 9446, 9457, 9468, 9479, 9490, 9500, 9510, 9521, 9531, 9541, 9551, 9561, 9570, 9580, 9590, 9599,
1416 9608, 9617, 9627, 9636, 9645, 9653, 9662, 9671, 9679, 9688, 9696, 9705, 9713, 9721, 9729, 9737,
1417 9745, 9753, 9761, 9769, 9777, 9784, 9792, 9799, 9807, 9814, 9821, 9829, 9836, 9843, 9850, 9857],
1418 [9864, 9878, 9892, 9905, 9918, 9931, 9944, 9956, 9969, 9981, 9993, 10005, 10017, 10029, 10040, 10051,
1419 10063, 10074, 10085, 10095, 10106, 10117, 10127, 10137, 10147, 10157, 10167, 10177, 10187, 10197, 10206, 10215,
1420 10225, 10234, 10243, 10252, 10261, 10270, 10279, 10287, 10296, 10304, 10313, 10321, 10330, 10338, 10346, 10354,
1421 10362, 10370, 10378, 10385, 10393, 10401, 10408, 10416, 10423, 10431, 10438, 10445, 10452, 10460, 10467, 10474],
1422 [10481, 10494, 10508, 10521, 10535, 10548, 10560, 10573, 10585, 10598, 10610, 10622, 10634, 10645, 10657, 10668,
1423 10679, 10690, 10701, 10712, 10723, 10733, 10743, 10754, 10764, 10774, 10784, 10794, 10803, 10813, 10823, 10832,
1424 10841, 10851, 10860, 10869, 10878, 10886, 10895, 10904, 10912, 10921, 10929, 10938, 10946, 10954, 10962, 10970,
1425 10978, 10986, 10994, 11002, 11010, 11017, 11025, 11032, 11040, 11047, 11054, 11062, 11069, 11076, 11083, 11090],
1426 [11097, 11111, 11125, 11138, 11151, 11164, 11177, 11189, 11202, 11214, 11226, 11238, 11250, 11262, 11273, 11284,
1427 11296, 11307, 11318, 11328, 11339, 11350, 11360, 11370, 11380, 11390, 11400, 11410, 11420, 11430, 11439, 11448,
1428 11458, 11467, 11476, 11485, 11494, 11503, 11512, 11520, 11529, 11538, 11546, 11554, 11563, 11571, 11579, 11587,
1429 11595, 11603, 11611, 11618, 11626, 11634, 11641, 11649, 11656, 11664, 11671, 11678, 11685, 11693, 11700, 11707],
1430 [11714, 11727, 11741, 11754, 11768, 11781, 11793, 11806, 11818, 11831, 11843, 11855, 11867, 11878, 11890, 11901,
1431 11912, 11923, 11934, 11945, 11956, 11966, 11976, 11987, 11997, 12007, 12017, 12027, 12036, 12046, 12056, 12065,
1432 12074, 12084, 12093, 12102, 12111, 12119, 12128, 12137, 12146, 12154, 12162, 12171, 12179, 12187, 12195, 12203,
1433 12211, 12219, 12227, 12235, 12243, 12250, 12258, 12265, 12273, 12280, 12287, 12295, 12302, 12309, 12316, 12323],
1434 [12330, 12344, 12358, 12371, 12384, 12397, 12410, 12423, 12435, 12447, 12459, 12471, 12483, 12495, 12506, 12517,
1435 12529, 12540, 12551, 12561, 12572, 12583, 12593, 12603, 12613, 12623, 12633, 12643, 12653, 12663, 12672, 12682,
1436 12691, 12700, 12709, 12718, 12727, 12736, 12745, 12753, 12762, 12771, 12779, 12787, 12796, 12804, 12812, 12820,
1437 12828, 12836, 12844, 12851, 12859, 12867, 12874, 12882, 12889, 12897, 12904, 12911, 12918, 12926, 12933, 12940],
1438 [12947, 12960, 12974, 12987, 13001, 13014, 13026, 13039, 13051, 13064, 13076, 13088, 13100, 13111, 13123, 13134,
1439 13145, 13156, 13167, 13178, 13189, 13199, 13209, 13220, 13230, 13240, 13250, 13260, 13269, 13279, 13289, 13298,
1440 13307, 13317, 13326, 13335, 13344, 13352, 13361, 13370, 13379, 13387, 13395, 13404, 13412, 13420, 13428, 13436,
1441 13444, 13452, 13460, 13468, 13476, 13483, 13491, 13498, 13506, 13513, 13521, 13528, 13535, 13542, 13549, 13556],
1442 [13563, 13577, 13591, 13604, 13617, 13630, 13643, 13656, 13668, 13680, 13692, 13704, 13716, 13728, 13739, 13750,
1443 13762, 13773, 13784, 13794, 13805, 13816, 13826, 13836, 13846, 13857, 13866, 13876, 13886, 13896, 13905, 13915,
1444 13924, 13933, 13942, 13951, 13960, 13969, 13978, 13986, 13995, 14004, 14012, 14020, 14029, 14037, 14045, 14053,
1445 14061, 14069, 14077, 14084, 14092, 14100, 14107, 14115, 14122, 14130, 14137, 14144, 14151, 14159, 14166, 14173],
1446 [14180, 14194, 14207, 14220, 14234, 14247, 14259, 14272, 14284, 14297, 14309, 14321, 14333, 14344, 14356, 14367,
1447 14378, 14389, 14400, 14411, 14422, 14432, 14443, 14453, 14463, 14473, 14483, 14493, 14502, 14512, 14522, 14531,
1448 14540, 14550, 14559, 14568, 14577, 14586, 14594, 14603, 14612, 14620, 14628, 14637, 14645, 14653, 14661, 14669,
1449 14677, 14685, 14693, 14701, 14709, 14716, 14724, 14731, 14739, 14746, 14754, 14761, 14768, 14775, 14782, 14789],
1450 [14796, 14810, 14824, 14837, 14850, 14863, 14876, 14889, 14901, 14913, 14925, 14937, 14949, 14961, 14972, 14984,
1451 14995, 15006, 15017, 15027, 15038, 15049, 15059, 15069, 15079, 15090, 15099, 15109, 15119, 15129, 15138, 15148,
1452 15157, 15166, 15175, 15184, 15193, 15202, 15211, 15219, 15228, 15237, 15245, 15253, 15262, 15270, 15278, 15286,
1453 15294, 15302, 15310, 15317, 15325, 15333, 15340, 15348, 15355, 15363, 15370, 15377, 15384, 15392, 15399, 15406],
1454 [15413, 15427, 15440, 15453, 15467, 15480, 15492, 15505, 15517, 15530, 15542, 15554, 15566, 15577, 15589, 15600,
1455 15611, 15622, 15633, 15644, 15655, 15665, 15676, 15686, 15696, 15706, 15716, 15726, 15736, 15745, 15755, 15764,
1456 15773, 15783, 15792, 15801, 15810, 15819, 15827, 15836, 15845, 15853, 15862, 15870, 15878, 15886, 15894, 15903,
1457 15910, 15918, 15926, 15934, 15942, 15949, 15957, 15964, 15972, 15979, 15987, 15994, 16001, 16008, 16015, 16022],
1458 [16029, 16043, 16057, 16070, 16083, 16096, 16109, 16122, 16134, 16146, 16158, 16170, 16182, 16194, 16205, 16217,
1459 16228, 16239, 16250, 16260, 16271, 16282, 16292, 16302, 16312, 16323, 16332, 16342, 16352, 16362, 16371, 16381,
1460 16390, 16399, 16408, 16417, 16426, 16435, 16444, 16452, 16461, 16470, 16478, 16486, 16495, 16503, 16511, 16519,
1461 16527, 16535, 16543, 16550, 16558, 16566, 16573, 16581, 16588, 16596, 16603, 16610, 16618, 16625, 16632, 16639],
1462 [16646, 16660, 16673, 16686, 16700, 16713, 16725, 16738, 16751, 16763, 16775, 16787, 16799, 16810, 16822, 16833,
1463 16844, 16855, 16866, 16877, 16888, 16898, 16909, 16919, 16929, 16939, 16949, 16959, 16969, 16978, 16988, 16997,
1464 17006, 17016, 17025, 17034, 17043, 17052, 17060, 17069, 17078, 17086, 17095, 17103, 17111, 17119, 17127, 17136,
1465 17143, 17151, 17159, 17167, 17175, 17182, 17190, 17197, 17205, 17212, 17220, 17227, 17234, 17241, 17248, 17255],
1466 [17262, 17276, 17290, 17303, 17316, 17329, 17342, 17355, 17367, 17379, 17391, 17403, 17415, 17427, 17438, 17450,
1467 17461, 17472, 17483, 17493, 17504, 17515, 17525, 17535, 17546, 17556, 17565, 17575, 17585, 17595, 17604, 17614,
1468 17623, 17632, 17641, 17650, 17659, 17668, 17677, 17685, 17694, 17703, 17711, 17719, 17728, 17736, 17744, 17752,
1469 17760, 17768, 17776, 17784, 17791, 17799, 17806, 17814, 17821, 17829, 17836, 17843, 17851, 17858, 17865, 17872],
1470 [17879, 17893, 17906, 17920, 17933, 17946, 17958, 17971, 17984, 17996, 18008, 18020, 18032, 18043, 18055, 18066,
1471 18077, 18088, 18099, 18110, 18121, 18131, 18142, 18152, 18162, 18172, 18182, 18192, 18202, 18211, 18221, 18230,
1472 18239, 18249, 18258, 18267, 18276, 18285, 18293, 18302, 18311, 18319, 18328, 18336, 18344, 18352, 18360, 18369,
1473 18377, 18384, 18392, 18400, 18408, 18415, 18423, 18430, 18438, 18445, 18453, 18460, 18467, 18474, 18481, 18488],
1474 [18495, 18509, 18523, 18536, 18549, 18562, 18575, 18588, 18600, 18612, 18624, 18636, 18648, 18660, 18671, 18683,
1475 18694, 18705, 18716, 18726, 18737, 18748, 18758, 18768, 18779, 18789, 18799, 18808, 18818, 18828, 18837, 18847,
1476 18856, 18865, 18874, 18883, 18892, 18901, 18910, 18919, 18927, 18936, 18944, 18952, 18961, 18969, 18977, 18985,
1477 18993, 19001, 19009, 19017, 19024, 19032, 19039, 19047, 19054, 19062, 19069, 19076, 19084, 19091, 19098, 19105],
1478 [19112, 19126, 19139, 19153, 19166, 19179, 19191, 19204, 19217, 19229, 19241, 19253, 19265, 19276, 19288, 19299,
1479 19310, 19321, 19332, 19343, 19354, 19364, 19375, 19385, 19395, 19405, 19415, 19425, 19435, 19444, 19454, 19463,
1480 19472, 19482, 19491, 19500, 19509, 19518, 19526, 19535, 19544, 19552, 19561, 19569, 19577, 19585, 19594, 19602,
1481 19610, 19617, 19625, 19633, 19641, 19648, 19656, 19663, 19671, 19678, 19686, 19693, 19700, 19707, 19714, 19721],
1482 [19728, 19742, 19756, 19769, 19782, 19795, 19808, 19821, 19833, 19845, 19857, 19869, 19881, 19893, 19904, 19916,
1483 19927, 19938, 19949, 19960, 19970, 19981, 19991, 20001, 20012, 20022, 20032, 20041, 20051, 20061, 20070, 20080,
1484 20089, 20098, 20107, 20116, 20125, 20134, 20143, 20152, 20160, 20169, 20177, 20185, 20194, 20202, 20210, 20218,
1485 20226, 20234, 20242, 20250, 20257, 20265, 20272, 20280, 20287, 20295, 20302, 20309, 20317, 20324, 20331, 20338],
1486 [20345, 20359, 20372, 20386, 20399, 20412, 20425, 20437, 20450, 20462, 20474, 20486, 20498, 20509, 20521, 20532,
1487 20543, 20554, 20565, 20576, 20587, 20597, 20608, 20618, 20628, 20638, 20648, 20658, 20668, 20677, 20687, 20696,
1488 20705, 20715, 20724, 20733, 20742, 20751, 20759, 20768, 20777, 20785, 20794, 20802, 20810, 20818, 20827, 20835,
1489 20843, 20850, 20858, 20866, 20874, 20881, 20889, 20896, 20904, 20911, 20919, 20926, 20933, 20940, 20947, 20954],
1490 [20961, 20975, 20989, 21002, 21015, 21028, 21041, 21054, 21066, 21078, 21090, 21102, 21114, 21126, 21137, 21149,
1491 21160, 21171, 21182, 21193, 21203, 21214, 21224, 21234, 21245, 21255, 21265, 21274, 21284, 21294, 21303, 21313,
1492 21322, 21331, 21340, 21349, 21358, 21367, 21376, 21385, 21393, 21402, 21410, 21418, 21427, 21435, 21443, 21451,
1493 21459, 21467, 21475, 21483, 21490, 21498, 21505, 21513, 21520, 21528, 21535, 21542, 21550, 21557, 21564, 21571],
1494 [21578, 21592, 21605, 21619, 21632, 21645, 21658, 21670, 21683, 21695, 21707, 21719, 21731, 21742, 21754, 21765,
1495 21776, 21787, 21798, 21809, 21820, 21830, 21841, 21851, 21861, 21871, 21881, 21891, 21901, 21910, 21920, 21929,
1496 21938, 21948, 21957, 21966, 21975, 21984, 21992, 22001, 22010, 22018, 22027, 22035, 22043, 22051, 22060, 22068,
1497 22076, 22083, 22091, 22099, 22107, 22114, 22122, 22129, 22137, 22144, 22152, 22159, 22166, 22173, 22180, 22187],
1498 [22194, 22208, 22222, 22235, 22248, 22261, 22274, 22287, 22299, 22311, 22323, 22335, 22347, 22359, 22370, 22382,
1499 22393, 22404, 22415, 22426, 22436, 22447, 22457, 22467, 22478, 22488, 22498, 22507, 22517, 22527, 22536, 22546,
1500 22555, 22564, 22573, 22582, 22591, 22600, 22609, 22618, 22626, 22635, 22643, 22651, 22660, 22668, 22676, 22684,
1501 22692, 22700, 22708, 22716, 22723, 22731, 22738, 22746, 22753, 22761, 22768, 22775, 22783, 22790, 22797, 22804],
1502 [22811, 22825, 22838, 22852, 22865, 22878, 22891, 22903, 22916, 22928, 22940, 22952, 22964, 22975, 22987, 22998,
1503 23009, 23020, 23031, 23042, 23053, 23063, 23074, 23084, 23094, 23104, 23114, 23124, 23134, 23143, 23153, 23162,
1504 23171, 23181, 23190, 23199, 23208, 23217, 23225, 23234, 23243, 23251, 23260, 23268, 23276, 23284, 23293, 23301,
1505 23309, 23316, 23324, 23332, 23340, 23347, 23355, 23363, 23370, 23377, 23385, 23392, 23399, 23406, 23413, 23420],
1506 [23427, 23441, 23455, 23468, 23481, 23494, 23507, 23520, 23532, 23544, 23556, 23568, 23580, 23592, 23603, 23615,
1507 23626, 23637, 23648, 23659, 23669, 23680, 23690, 23700, 23711, 23721, 23731, 23740, 23750, 23760, 23769, 23779,
1508 23788, 23797, 23806, 23815, 23824, 23833, 23842, 23851, 23859, 23868, 23876, 23884, 23893, 23901, 23909, 23917,
1509 23925, 23933, 23941, 23949, 23956, 23964, 23972, 23979, 23986, 23994, 24001, 24008, 24016, 24023, 24030, 24037],
1510 [24044, 24058, 24071, 24085, 24098, 24111, 24124, 24136, 24149, 24161, 24173, 24185, 24197, 24208, 24220, 24231,
1511 24242, 24253, 24264, 24275, 24286, 24296, 24307, 24317, 24327, 24337, 24347, 24357, 24367, 24376, 24386, 24395,
1512 24405, 24414, 24423, 24432, 24441, 24450, 24458, 24467, 24476, 24484, 24493, 24501, 24509, 24517, 24526, 24534,
1513 24542, 24550, 24557, 24565, 24573, 24580, 24588, 24596, 24603, 24610, 24618, 24625, 24632, 24639, 24646, 24653],
1514 [24660, 24674, 24688, 24701, 24714, 24727, 24740, 24753, 24765, 24777, 24790, 24801, 24813, 24825, 24836, 24848,
1515 24859, 24870, 24881, 24892, 24902, 24913, 24923, 24933, 24944, 24954, 24964, 24973, 24983, 24993, 25002, 25012,
1516 25021, 25030, 25039, 25048, 25057, 25066, 25075, 25084, 25092, 25101, 25109, 25117, 25126, 25134, 25142, 25150,
1517 25158, 25166, 25174, 25182, 25189, 25197, 25205, 25212, 25219, 25227, 25234, 25241, 25249, 25256, 25263, 25270],
1518 [25277, 25291, 25304, 25318, 25331, 25344, 25357, 25369, 25382, 25394, 25406, 25418, 25430, 25441, 25453, 25464,
1519 25475, 25486, 25497, 25508, 25519, 25529, 25540, 25550, 25560, 25570, 25580, 25590, 25600, 25609, 25619, 25628,
1520 25638, 25647, 25656, 25665, 25674, 25683, 25691, 25700, 25709, 25717, 25726, 25734, 25742, 25750, 25759, 25767,
1521 25775, 25783, 25790, 25798, 25806, 25813, 25821, 25829, 25836, 25843, 25851, 25858, 25865, 25872, 25879, 25886],
1522 [25893, 25907, 25921, 25934, 25947, 25960, 25973, 25986, 25998, 26010, 26023, 26034, 26046, 26058, 26069, 26081,
1523 26092, 26103, 26114, 26125, 26135, 26146, 26156, 26166, 26177, 26187, 26197, 26206, 26216, 26226, 26235, 26245,
1524 26254, 26263, 26272, 26281, 26290, 26299, 26308, 26317, 26325, 26334, 26342, 26351, 26359, 26367, 26375, 26383,
1525 26391, 26399, 26407, 26415, 26422, 26430, 26438, 26445, 26453, 26460, 26467, 26474, 26482, 26489, 26496, 26503],
1526 [26510, 26524, 26537, 26551, 26564, 26577, 26590, 26602, 26615, 26627, 26639, 26651, 26663, 26674, 26686, 26697,
1527 26708, 26719, 26730, 26741, 26752, 26762, 26773, 26783, 26793, 26803, 26813, 26823, 26833, 26842, 26852, 26861,
1528 26871, 26880, 26889, 26898, 26907, 26916, 26924, 26933, 26942, 26950, 26959, 26967, 26975, 26983, 26992, 27000,
1529 27008, 27016, 27023, 27031, 27039, 27046, 27054, 27062, 27069, 27076, 27084, 27091, 27098, 27105, 27112, 27119],
1530 [27126, 27140, 27154, 27167, 27180, 27193, 27206, 27219, 27231, 27243, 27256, 27267, 27279, 27291, 27302, 27314,
1531 27325, 27336, 27347, 27358, 27368, 27379, 27389, 27399, 27410, 27420, 27430, 27439, 27449, 27459, 27468, 27478,
1532 27487, 27496, 27505, 27514, 27523, 27532, 27541, 27550, 27558, 27567, 27575, 27584, 27592, 27600, 27608, 27616,
1533 27624, 27632, 27640, 27648, 27655, 27663, 27671, 27678, 27686, 27693, 27700, 27707, 27715, 27722, 27729, 27736],
1534 [27743, 27757, 27770, 27784, 27797, 27810, 27823, 27835, 27848, 27860, 27872, 27884, 27896, 27907, 27919, 27930,
1535 27941, 27952, 27963, 27974, 27985, 27995, 28006, 28016, 28026, 28036, 28046, 28056, 28066, 28075, 28085, 28094,
1536 28104, 28113, 28122, 28131, 28140, 28149, 28157, 28166, 28175, 28183, 28192, 28200, 28208, 28217, 28225, 28233,
1537 28241, 28249, 28256, 28264, 28272, 28280, 28287, 28295, 28302, 28309, 28317, 28324, 28331, 28338, 28345, 28352],
1538 [28359, 28373, 28387, 28400, 28413, 28426, 28439, 28452, 28464, 28476, 28489, 28501, 28512, 28524, 28535, 28547,
1539 28558, 28569, 28580, 28591, 28601, 28612, 28622, 28633, 28643, 28653, 28663, 28672, 28682, 28692, 28701, 28711,
1540 28720, 28729, 28738, 28747, 28756, 28765, 28774, 28783, 28791, 28800, 28808, 28817, 28825, 28833, 28841, 28849,
1541 28857, 28865, 28873, 28881, 28888, 28896, 28904, 28911, 28919, 28926, 28933, 28941, 28948, 28955, 28962, 28969],
1542 [28976, 28990, 29003, 29017, 29030, 29043, 29056, 29068, 29081, 29093, 29105, 29117, 29129, 29140, 29152, 29163,
1543 29174, 29185, 29196, 29207, 29218, 29228, 29239, 29249, 29259, 29269, 29279, 29289, 29299, 29308, 29318, 29327,
1544 29337, 29346, 29355, 29364, 29373, 29382, 29390, 29399, 29408, 29416, 29425, 29433, 29441, 29450, 29458, 29466,
1545 29474, 29482, 29489, 29497, 29505, 29513, 29520, 29528, 29535, 29542, 29550, 29557, 29564, 29571, 29578, 29585],
1546 [29592, 29606, 29620, 29633, 29646, 29659, 29672, 29685, 29697, 29709, 29722, 29734, 29745, 29757, 29768, 29780,
1547 29791, 29802, 29813, 29824, 29834, 29845, 29855, 29866, 29876, 29886, 29896, 29906, 29915, 29925, 29934, 29944,
1548 29953, 29962, 29971, 29980, 29989, 29998, 30007, 30016, 30024, 30033, 30041, 30050, 30058, 30066, 30074, 30082,
1549 30090, 30098, 30106, 30114, 30121, 30129, 30137, 30144, 30152, 30159, 30166, 30174, 30181, 30188, 30195, 30202],
1550 [30209, 30223, 30236, 30250, 30263, 30276, 30289, 30301, 30314, 30326, 30338, 30350, 30362, 30373, 30385, 30396,
1551 30407, 30418, 30429, 30440, 30451, 30461, 30472, 30482, 30492, 30502, 30512, 30522, 30532, 30541, 30551, 30560,
1552 30570, 30579, 30588, 30597, 30606, 30615, 30624, 30632, 30641, 30649, 30658, 30666, 30674, 30683, 30691, 30699,
1553 30707, 30715, 30722, 30730, 30738, 30746, 30753, 30761, 30768, 30775, 30783, 30790, 30797, 30804, 30811, 30818],
1554 [30825, 30839, 30853, 30866, 30879, 30892, 30905, 30918, 30930, 30943, 30955, 30967, 30978, 30990, 31001, 31013,
1555 31024, 31035, 31046, 31057, 31067, 31078, 31088, 31099, 31109, 31119, 31129, 31139, 31148, 31158, 31167, 31177,
1556 31186, 31195, 31204, 31213, 31222, 31231, 31240, 31249, 31257, 31266, 31274, 31283, 31291, 31299, 31307, 31315,
1557 31323, 31331, 31339, 31347, 31354, 31362, 31370, 31377, 31385, 31392, 31399, 31407, 31414, 31421, 31428, 31435],
1558 [31442, 31456, 31469, 31483, 31496, 31509, 31522, 31534, 31547, 31559, 31571, 31583, 31595, 31606, 31618, 31629,
1559 31640, 31652, 31662, 31673, 31684, 31694, 31705, 31715, 31725, 31735, 31745, 31755, 31765, 31774, 31784, 31793,
1560 31803, 31812, 31821, 31830, 31839, 31848, 31857, 31865, 31874, 31882, 31891, 31899, 31907, 31916, 31924, 31932,
1561 31940, 31948, 31955, 31963, 31971, 31979, 31986, 31994, 32001, 32008, 32016, 32023, 32030, 32037, 32044, 32052],
1562 [32058, 32072, 32086, 32099, 32112, 32125, 32138, 32151, 32163, 32176, 32188, 32200, 32211, 32223, 32234, 32246,
1563 32257, 32268, 32279, 32290, 32300, 32311, 32321, 32332, 32342, 32352, 32362, 32372, 32381, 32391, 32400, 32410,
1564 32419, 32428, 32437, 32446, 32455, 32464, 32473, 32482, 32490, 32499, 32507, 32516, 32524, 32532, 32540, 32548,
1565 32556, 32564, 32572, 32580, 32587, 32595, 32603, 32610, 32618, 32625, 32632, 32640, 32647, 32654, 32661, 32668],
1566 [32675, 32689, 32702, 32716, 32729, 32742, 32755, 32767, 32780, 32792, 32804, 32816, 32828, 32839, 32851, 32862,
1567 32873, 32885, 32895, 32906, 32917, 32927, 32938, 32948, 32958, 32968, 32978, 32988, 32998, 33007, 33017, 33026,
1568 33036, 33045, 33054, 33063, 33072, 33081, 33090, 33098, 33107, 33115, 33124, 33132, 33140, 33149, 33157, 33165,
1569 33173, 33181, 33188, 33196, 33204, 33212, 33219, 33227, 33234, 33241, 33249, 33256, 33263, 33270, 33278, 33285],
1570 [33292, 33305, 33319, 33332, 33345, 33358, 33371, 33384, 33396, 33409, 33421, 33433, 33444, 33456, 33467, 33479,
1571 33490, 33501, 33512, 33523, 33533, 33544, 33554, 33565, 33575, 33585, 33595, 33605, 33614, 33624, 33633, 33643,
1572 33652, 33661, 33670, 33680, 33688, 33697, 33706, 33715, 33723, 33732, 33740, 33749, 33757, 33765, 33773, 33781,
1573 33789, 33797, 33805, 33813, 33820, 33828, 33836, 33843, 33851, 33858, 33865, 33873, 33880, 33887, 33894, 33901],
1574 [33908, 33922, 33935, 33949, 33962, 33975, 33988, 34000, 34013, 34025, 34037, 34049, 34061, 34072, 34084, 34095,
1575 34106, 34118, 34128, 34139, 34150, 34160, 34171, 34181, 34191, 34201, 34211, 34221, 34231, 34240, 34250, 34259,
1576 34269, 34278, 34287, 34296, 34305, 34314, 34323, 34331, 34340, 34348, 34357, 34365, 34373, 34382, 34390, 34398,
1577 34406, 34414, 34422, 34429, 34437, 34445, 34452, 34460, 34467, 34475, 34482, 34489, 34496, 34503, 34511, 34518],
1578 [34525, 34538, 34552, 34565, 34578, 34591, 34604, 34617, 34629, 34642, 34654, 34666, 34677, 34689, 34700, 34712,
1579 34723, 34734, 34745, 34756, 34766, 34777, 34787, 34798, 34808, 34818, 34828, 34838, 34847, 34857, 34866, 34876,
1580 34885, 34894, 34904, 34913, 34921, 34930, 34939, 34948, 34956, 34965, 34973, 34982, 34990, 34998, 35006, 35014,
1581 35022, 35030, 35038, 35046, 35053, 35061, 35069, 35076, 35084, 35091, 35098, 35106, 35113, 35120, 35127, 35134],
1582 [35141, 35155, 35168, 35182, 35195, 35208, 35221, 35233, 35246, 35258, 35270, 35282, 35294, 35306, 35317, 35328,
1583 35340, 35351, 35361, 35372, 35383, 35393, 35404, 35414, 35424, 35434, 35444, 35454, 35464, 35473, 35483, 35492,
1584 35502, 35511, 35520, 35529, 35538, 35547, 35556, 35564, 35573, 35581, 35590, 35598, 35606, 35615, 35623, 35631,
1585 35639, 35647, 35655, 35662, 35670, 35678, 35685, 35693, 35700, 35708, 35715, 35722, 35729, 35736, 35744, 35751],
1586 [35758, 35771, 35785, 35798, 35811, 35824, 35837, 35850, 35862, 35875, 35887, 35899, 35910, 35922, 35934, 35945,
1587 35956, 35967, 35978, 35989, 35999, 36010, 36020, 36031, 36041, 36051, 36061, 36071, 36080, 36090, 36099, 36109,
1588 36118, 36127, 36137, 36146, 36154, 36163, 36172, 36181, 36189, 36198, 36206, 36215, 36223, 36231, 36239, 36247,
1589 36255, 36263, 36271, 36279, 36287, 36294, 36302, 36309, 36317, 36324, 36331, 36339, 36346, 36353, 36360, 36367],
1590 [36374, 36388, 36401, 36415, 36428, 36441, 36454, 36466, 36479, 36491, 36503, 36515, 36527, 36539, 36550, 36561,
1591 36573, 36584, 36594, 36605, 36616, 36626, 36637, 36647, 36657, 36667, 36677, 36687, 36697, 36706, 36716, 36725,
1592 36735, 36744, 36753, 36762, 36771, 36780, 36789, 36797, 36806, 36814, 36823, 36831, 36839, 36848, 36856, 36864,
1593 36872, 36880, 36888, 36895, 36903, 36911, 36918, 36926, 36933, 36941, 36948, 36955, 36962, 36969, 36977, 36984],
1594 [36991, 37004, 37018, 37031, 37044, 37057, 37070, 37083, 37095, 37108, 37120, 37132, 37143, 37155, 37167, 37178,
1595 37189, 37200, 37211, 37222, 37232, 37243, 37253, 37264, 37274, 37284, 37294, 37304, 37313, 37323, 37332, 37342,
1596 37351, 37360, 37370, 37379, 37388, 37396, 37405, 37414, 37422, 37431, 37439, 37448, 37456, 37464, 37472, 37480,
1597 37488, 37496, 37504, 37512, 37520, 37527, 37535, 37542, 37550, 37557, 37564, 37572, 37579, 37586, 37593, 37600],
1598 [37607, 37621, 37634, 37648, 37661, 37674, 37687, 37699, 37712, 37724, 37736, 37748, 37760, 37772, 37783, 37794,
1599 37806, 37817, 37828, 37838, 37849, 37859, 37870, 37880, 37890, 37900, 37910, 37920, 37930, 37939, 37949, 37958,
1600 37968, 37977, 37986, 37995, 38004, 38013, 38022, 38030, 38039, 38047, 38056, 38064, 38072, 38081, 38089, 38097,
1601 38105, 38113, 38121, 38128, 38136, 38144, 38151, 38159, 38166, 38174, 38181, 38188, 38195, 38202, 38210, 38217],
1602 [38224, 38237, 38251, 38264, 38278, 38290, 38303, 38316, 38328, 38341, 38353, 38365, 38376, 38388, 38400, 38411,
1603 38422, 38433, 38444, 38455, 38465, 38476, 38486, 38497, 38507, 38517, 38527, 38537, 38546, 38556, 38565, 38575,
1604 38584, 38593, 38603, 38612, 38621, 38629, 38638, 38647, 38655, 38664, 38672, 38681, 38689, 38697, 38705, 38713,
1605 38721, 38729, 38737, 38745, 38753, 38760, 38768, 38775, 38783, 38790, 38797, 38805, 38812, 38819, 38826, 38833],
1606 [38840, 38854, 38867, 38881, 38894, 38907, 38920, 38932, 38945, 38957, 38969, 38981, 38993, 39005, 39016, 39027,
1607 39039, 39050, 39061, 39071, 39082, 39092, 39103, 39113, 39123, 39133, 39143, 39153, 39163, 39172, 39182, 39191,
1608 39201, 39210, 39219, 39228, 39237, 39246, 39255, 39263, 39272, 39280, 39289, 39297, 39305, 39314, 39322, 39330,
1609 39338, 39346, 39354, 39361, 39369, 39377, 39384, 39392, 39399, 39407, 39414, 39421, 39428, 39436, 39443, 39450],
1612 /// Approximate `log10(numerator / denominator) * 2048` using a look-up table.
1614 pub fn negative_log10_times_2048(numerator: u64, denominator: u64) -> u64 {
1615 // Multiply the -1 through to avoid needing to use signed numbers.
1616 (log10_times_2048(denominator) - log10_times_2048(numerator)) as u64
1620 fn log10_times_2048(x: u64) -> u16 {
1621 debug_assert_ne!(x, 0);
1622 let most_significant_bit = HIGHEST_BIT - x.leading_zeros();
1623 let lower_bits = (x >> most_significant_bit.saturating_sub(LOWER_BITS)) & LOWER_BITMASK;
1624 LOG10_TIMES_2048[most_significant_bit as usize][lower_bits as usize]
1632 fn prints_negative_log10_times_2048_lookup_table() {
1633 for msb in 0..BITS {
1634 for i in 0..LOWER_BITS_BOUND {
1635 let x = ((LOWER_BITS_BOUND + i) << (HIGHEST_BIT - LOWER_BITS)) >> (HIGHEST_BIT - msb);
1636 let log10_times_2048 = ((x as f64).log10() * 2048.0).round() as u16;
1637 assert_eq!(log10_times_2048, LOG10_TIMES_2048[msb as usize][i as usize]);
1639 if i % LOWER_BITS_BOUND == 0 {
1640 print!("\t\t[{}, ", log10_times_2048);
1641 } else if i % LOWER_BITS_BOUND == LOWER_BITS_BOUND - 1 {
1642 println!("{}],", log10_times_2048);
1643 } else if i % (LOWER_BITS_BOUND/4) == LOWER_BITS_BOUND/4 - 1 {
1644 print!("{},\n\t\t\t", log10_times_2048);
1646 print!("{}, ", log10_times_2048);
1654 impl<G: Deref<Target = NetworkGraph<L>>, L: Deref, T: Time> Writeable for ProbabilisticScorerUsingTime<G, L, T> where L::Target: Logger {
1656 fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1657 write_tlv_fields!(w, {
1658 (0, self.channel_liquidities, required),
1664 impl<G: Deref<Target = NetworkGraph<L>>, L: Deref, T: Time>
1665 ReadableArgs<(ProbabilisticScoringDecayParameters, G, L)> for ProbabilisticScorerUsingTime<G, L, T> where L::Target: Logger {
1668 r: &mut R, args: (ProbabilisticScoringDecayParameters, G, L)
1669 ) -> Result<Self, DecodeError> {
1670 let (decay_params, network_graph, logger) = args;
1671 let mut channel_liquidities = HashMap::new();
1672 read_tlv_fields!(r, {
1673 (0, channel_liquidities, required),
1679 channel_liquidities,
1684 impl<T: Time> Writeable for ChannelLiquidity<T> {
1686 fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
1687 let duration_since_epoch = T::duration_since_epoch() - self.last_updated.elapsed();
1688 write_tlv_fields!(w, {
1689 (0, self.min_liquidity_offset_msat, required),
1690 (1, Some(self.min_liquidity_offset_history), option),
1691 (2, self.max_liquidity_offset_msat, required),
1692 (3, Some(self.max_liquidity_offset_history), option),
1693 (4, duration_since_epoch, required),
1699 impl<T: Time> Readable for ChannelLiquidity<T> {
1701 fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
1702 let mut min_liquidity_offset_msat = 0;
1703 let mut max_liquidity_offset_msat = 0;
1704 let mut min_liquidity_offset_history = Some(HistoricalBucketRangeTracker::new());
1705 let mut max_liquidity_offset_history = Some(HistoricalBucketRangeTracker::new());
1706 let mut duration_since_epoch = Duration::from_secs(0);
1707 read_tlv_fields!(r, {
1708 (0, min_liquidity_offset_msat, required),
1709 (1, min_liquidity_offset_history, option),
1710 (2, max_liquidity_offset_msat, required),
1711 (3, max_liquidity_offset_history, option),
1712 (4, duration_since_epoch, required),
1714 // On rust prior to 1.60 `Instant::duration_since` will panic if time goes backwards.
1715 // We write `last_updated` as wallclock time even though its ultimately an `Instant` (which
1716 // is a time from a monotonic clock usually represented as an offset against boot time).
1717 // Thus, we have to construct an `Instant` by subtracting the difference in wallclock time
1718 // from the one that was written. However, because `Instant` can panic if we construct one
1719 // in the future, we must handle wallclock time jumping backwards, which we do by simply
1720 // using `Instant::now()` in that case.
1721 let wall_clock_now = T::duration_since_epoch();
1723 let last_updated = if wall_clock_now > duration_since_epoch {
1724 now - (wall_clock_now - duration_since_epoch)
1727 min_liquidity_offset_msat,
1728 max_liquidity_offset_msat,
1729 min_liquidity_offset_history: min_liquidity_offset_history.unwrap(),
1730 max_liquidity_offset_history: max_liquidity_offset_history.unwrap(),
1738 use super::{ChannelLiquidity, HistoricalBucketRangeTracker, ProbabilisticScoringFeeParameters, ProbabilisticScoringDecayParameters, ProbabilisticScorerUsingTime};
1739 use crate::blinded_path::{BlindedHop, BlindedPath};
1740 use crate::util::config::UserConfig;
1741 use crate::util::time::Time;
1742 use crate::util::time::tests::SinceEpoch;
1744 use crate::ln::channelmanager;
1745 use crate::ln::msgs::{ChannelAnnouncement, ChannelUpdate, UnsignedChannelAnnouncement, UnsignedChannelUpdate};
1746 use crate::routing::gossip::{EffectiveCapacity, NetworkGraph, NodeId};
1747 use crate::routing::router::{BlindedTail, Path, RouteHop};
1748 use crate::routing::scoring::{ChannelUsage, Score};
1749 use crate::util::ser::{ReadableArgs, Writeable};
1750 use crate::util::test_utils::{self, TestLogger};
1752 use bitcoin::blockdata::constants::genesis_block;
1753 use bitcoin::hashes::Hash;
1754 use bitcoin::hashes::sha256d::Hash as Sha256dHash;
1755 use bitcoin::network::constants::Network;
1756 use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey};
1757 use core::time::Duration;
1760 fn source_privkey() -> SecretKey {
1761 SecretKey::from_slice(&[42; 32]).unwrap()
1764 fn target_privkey() -> SecretKey {
1765 SecretKey::from_slice(&[43; 32]).unwrap()
1768 fn source_pubkey() -> PublicKey {
1769 let secp_ctx = Secp256k1::new();
1770 PublicKey::from_secret_key(&secp_ctx, &source_privkey())
1773 fn target_pubkey() -> PublicKey {
1774 let secp_ctx = Secp256k1::new();
1775 PublicKey::from_secret_key(&secp_ctx, &target_privkey())
1778 fn source_node_id() -> NodeId {
1779 NodeId::from_pubkey(&source_pubkey())
1782 fn target_node_id() -> NodeId {
1783 NodeId::from_pubkey(&target_pubkey())
1786 // `ProbabilisticScorer` tests
1788 /// A probabilistic scorer for testing with time that can be manually advanced.
1789 type ProbabilisticScorer<'a> = ProbabilisticScorerUsingTime::<&'a NetworkGraph<&'a TestLogger>, &'a TestLogger, SinceEpoch>;
1791 fn sender_privkey() -> SecretKey {
1792 SecretKey::from_slice(&[41; 32]).unwrap()
1795 fn recipient_privkey() -> SecretKey {
1796 SecretKey::from_slice(&[45; 32]).unwrap()
1799 fn sender_pubkey() -> PublicKey {
1800 let secp_ctx = Secp256k1::new();
1801 PublicKey::from_secret_key(&secp_ctx, &sender_privkey())
1804 fn recipient_pubkey() -> PublicKey {
1805 let secp_ctx = Secp256k1::new();
1806 PublicKey::from_secret_key(&secp_ctx, &recipient_privkey())
1809 fn sender_node_id() -> NodeId {
1810 NodeId::from_pubkey(&sender_pubkey())
1813 fn recipient_node_id() -> NodeId {
1814 NodeId::from_pubkey(&recipient_pubkey())
1817 fn network_graph(logger: &TestLogger) -> NetworkGraph<&TestLogger> {
1818 let mut network_graph = NetworkGraph::new(Network::Testnet, logger);
1819 add_channel(&mut network_graph, 42, source_privkey(), target_privkey());
1820 add_channel(&mut network_graph, 43, target_privkey(), recipient_privkey());
1826 network_graph: &mut NetworkGraph<&TestLogger>, short_channel_id: u64, node_1_key: SecretKey,
1827 node_2_key: SecretKey
1829 let genesis_hash = genesis_block(Network::Testnet).header.block_hash();
1830 let node_1_secret = &SecretKey::from_slice(&[39; 32]).unwrap();
1831 let node_2_secret = &SecretKey::from_slice(&[40; 32]).unwrap();
1832 let secp_ctx = Secp256k1::new();
1833 let unsigned_announcement = UnsignedChannelAnnouncement {
1834 features: channelmanager::provided_channel_features(&UserConfig::default()),
1835 chain_hash: genesis_hash,
1837 node_id_1: NodeId::from_pubkey(&PublicKey::from_secret_key(&secp_ctx, &node_1_key)),
1838 node_id_2: NodeId::from_pubkey(&PublicKey::from_secret_key(&secp_ctx, &node_2_key)),
1839 bitcoin_key_1: NodeId::from_pubkey(&PublicKey::from_secret_key(&secp_ctx, &node_1_secret)),
1840 bitcoin_key_2: NodeId::from_pubkey(&PublicKey::from_secret_key(&secp_ctx, &node_2_secret)),
1841 excess_data: Vec::new(),
1843 let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
1844 let signed_announcement = ChannelAnnouncement {
1845 node_signature_1: secp_ctx.sign_ecdsa(&msghash, &node_1_key),
1846 node_signature_2: secp_ctx.sign_ecdsa(&msghash, &node_2_key),
1847 bitcoin_signature_1: secp_ctx.sign_ecdsa(&msghash, &node_1_secret),
1848 bitcoin_signature_2: secp_ctx.sign_ecdsa(&msghash, &node_2_secret),
1849 contents: unsigned_announcement,
1851 let chain_source: Option<&crate::util::test_utils::TestChainSource> = None;
1852 network_graph.update_channel_from_announcement(
1853 &signed_announcement, &chain_source).unwrap();
1854 update_channel(network_graph, short_channel_id, node_1_key, 0, 1_000);
1855 update_channel(network_graph, short_channel_id, node_2_key, 1, 0);
1859 network_graph: &mut NetworkGraph<&TestLogger>, short_channel_id: u64, node_key: SecretKey,
1860 flags: u8, htlc_maximum_msat: u64
1862 let genesis_hash = genesis_block(Network::Testnet).header.block_hash();
1863 let secp_ctx = Secp256k1::new();
1864 let unsigned_update = UnsignedChannelUpdate {
1865 chain_hash: genesis_hash,
1869 cltv_expiry_delta: 18,
1870 htlc_minimum_msat: 0,
1873 fee_proportional_millionths: 0,
1874 excess_data: Vec::new(),
1876 let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_update.encode()[..])[..]);
1877 let signed_update = ChannelUpdate {
1878 signature: secp_ctx.sign_ecdsa(&msghash, &node_key),
1879 contents: unsigned_update,
1881 network_graph.update_channel(&signed_update).unwrap();
1884 fn path_hop(pubkey: PublicKey, short_channel_id: u64, fee_msat: u64) -> RouteHop {
1885 let config = UserConfig::default();
1888 node_features: channelmanager::provided_node_features(&config),
1890 channel_features: channelmanager::provided_channel_features(&config),
1892 cltv_expiry_delta: 18,
1896 fn payment_path_for_amount(amount_msat: u64) -> Path {
1899 path_hop(source_pubkey(), 41, 1),
1900 path_hop(target_pubkey(), 42, 2),
1901 path_hop(recipient_pubkey(), 43, amount_msat),
1902 ], blinded_tail: None,
1907 fn liquidity_bounds_directed_from_lowest_node_id() {
1908 let logger = TestLogger::new();
1909 let last_updated = SinceEpoch::now();
1910 let network_graph = network_graph(&logger);
1911 let decay_params = ProbabilisticScoringDecayParameters::default();
1912 let mut scorer = ProbabilisticScorer::new(decay_params, &network_graph, &logger)
1915 min_liquidity_offset_msat: 700, max_liquidity_offset_msat: 100, last_updated,
1916 min_liquidity_offset_history: HistoricalBucketRangeTracker::new(),
1917 max_liquidity_offset_history: HistoricalBucketRangeTracker::new(),
1921 min_liquidity_offset_msat: 700, max_liquidity_offset_msat: 100, last_updated,
1922 min_liquidity_offset_history: HistoricalBucketRangeTracker::new(),
1923 max_liquidity_offset_history: HistoricalBucketRangeTracker::new(),
1925 let source = source_node_id();
1926 let target = target_node_id();
1927 let recipient = recipient_node_id();
1928 assert!(source > target);
1929 assert!(target < recipient);
1931 // Update minimum liquidity.
1933 let liquidity = scorer.channel_liquidities.get(&42).unwrap()
1934 .as_directed(&source, &target, 0, 1_000, decay_params);
1935 assert_eq!(liquidity.min_liquidity_msat(), 100);
1936 assert_eq!(liquidity.max_liquidity_msat(), 300);
1938 let liquidity = scorer.channel_liquidities.get(&42).unwrap()
1939 .as_directed(&target, &source, 0, 1_000, decay_params);
1940 assert_eq!(liquidity.min_liquidity_msat(), 700);
1941 assert_eq!(liquidity.max_liquidity_msat(), 900);
1943 scorer.channel_liquidities.get_mut(&42).unwrap()
1944 .as_directed_mut(&source, &target, 0, 1_000, decay_params)
1945 .set_min_liquidity_msat(200);
1947 let liquidity = scorer.channel_liquidities.get(&42).unwrap()
1948 .as_directed(&source, &target, 0, 1_000, decay_params);
1949 assert_eq!(liquidity.min_liquidity_msat(), 200);
1950 assert_eq!(liquidity.max_liquidity_msat(), 300);
1952 let liquidity = scorer.channel_liquidities.get(&42).unwrap()
1953 .as_directed(&target, &source, 0, 1_000, decay_params);
1954 assert_eq!(liquidity.min_liquidity_msat(), 700);
1955 assert_eq!(liquidity.max_liquidity_msat(), 800);
1957 // Update maximum liquidity.
1959 let liquidity = scorer.channel_liquidities.get(&43).unwrap()
1960 .as_directed(&target, &recipient, 0, 1_000, decay_params);
1961 assert_eq!(liquidity.min_liquidity_msat(), 700);
1962 assert_eq!(liquidity.max_liquidity_msat(), 900);
1964 let liquidity = scorer.channel_liquidities.get(&43).unwrap()
1965 .as_directed(&recipient, &target, 0, 1_000, decay_params);
1966 assert_eq!(liquidity.min_liquidity_msat(), 100);
1967 assert_eq!(liquidity.max_liquidity_msat(), 300);
1969 scorer.channel_liquidities.get_mut(&43).unwrap()
1970 .as_directed_mut(&target, &recipient, 0, 1_000, decay_params)
1971 .set_max_liquidity_msat(200);
1973 let liquidity = scorer.channel_liquidities.get(&43).unwrap()
1974 .as_directed(&target, &recipient, 0, 1_000, decay_params);
1975 assert_eq!(liquidity.min_liquidity_msat(), 0);
1976 assert_eq!(liquidity.max_liquidity_msat(), 200);
1978 let liquidity = scorer.channel_liquidities.get(&43).unwrap()
1979 .as_directed(&recipient, &target, 0, 1_000, decay_params);
1980 assert_eq!(liquidity.min_liquidity_msat(), 800);
1981 assert_eq!(liquidity.max_liquidity_msat(), 1000);
1985 fn resets_liquidity_upper_bound_when_crossed_by_lower_bound() {
1986 let logger = TestLogger::new();
1987 let last_updated = SinceEpoch::now();
1988 let network_graph = network_graph(&logger);
1989 let decay_params = ProbabilisticScoringDecayParameters::default();
1990 let mut scorer = ProbabilisticScorer::new(decay_params, &network_graph, &logger)
1993 min_liquidity_offset_msat: 200, max_liquidity_offset_msat: 400, last_updated,
1994 min_liquidity_offset_history: HistoricalBucketRangeTracker::new(),
1995 max_liquidity_offset_history: HistoricalBucketRangeTracker::new(),
1997 let source = source_node_id();
1998 let target = target_node_id();
1999 assert!(source > target);
2001 // Check initial bounds.
2002 let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2003 .as_directed(&source, &target, 0, 1_000, decay_params);
2004 assert_eq!(liquidity.min_liquidity_msat(), 400);
2005 assert_eq!(liquidity.max_liquidity_msat(), 800);
2007 let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2008 .as_directed(&target, &source, 0, 1_000, decay_params);
2009 assert_eq!(liquidity.min_liquidity_msat(), 200);
2010 assert_eq!(liquidity.max_liquidity_msat(), 600);
2012 // Reset from source to target.
2013 scorer.channel_liquidities.get_mut(&42).unwrap()
2014 .as_directed_mut(&source, &target, 0, 1_000, decay_params)
2015 .set_min_liquidity_msat(900);
2017 let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2018 .as_directed(&source, &target, 0, 1_000, decay_params);
2019 assert_eq!(liquidity.min_liquidity_msat(), 900);
2020 assert_eq!(liquidity.max_liquidity_msat(), 1_000);
2022 let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2023 .as_directed(&target, &source, 0, 1_000, decay_params);
2024 assert_eq!(liquidity.min_liquidity_msat(), 0);
2025 assert_eq!(liquidity.max_liquidity_msat(), 100);
2027 // Reset from target to source.
2028 scorer.channel_liquidities.get_mut(&42).unwrap()
2029 .as_directed_mut(&target, &source, 0, 1_000, decay_params)
2030 .set_min_liquidity_msat(400);
2032 let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2033 .as_directed(&source, &target, 0, 1_000, decay_params);
2034 assert_eq!(liquidity.min_liquidity_msat(), 0);
2035 assert_eq!(liquidity.max_liquidity_msat(), 600);
2037 let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2038 .as_directed(&target, &source, 0, 1_000, decay_params);
2039 assert_eq!(liquidity.min_liquidity_msat(), 400);
2040 assert_eq!(liquidity.max_liquidity_msat(), 1_000);
2044 fn resets_liquidity_lower_bound_when_crossed_by_upper_bound() {
2045 let logger = TestLogger::new();
2046 let last_updated = SinceEpoch::now();
2047 let network_graph = network_graph(&logger);
2048 let decay_params = ProbabilisticScoringDecayParameters::default();
2049 let mut scorer = ProbabilisticScorer::new(decay_params, &network_graph, &logger)
2052 min_liquidity_offset_msat: 200, max_liquidity_offset_msat: 400, last_updated,
2053 min_liquidity_offset_history: HistoricalBucketRangeTracker::new(),
2054 max_liquidity_offset_history: HistoricalBucketRangeTracker::new(),
2056 let source = source_node_id();
2057 let target = target_node_id();
2058 assert!(source > target);
2060 // Check initial bounds.
2061 let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2062 .as_directed(&source, &target, 0, 1_000, decay_params);
2063 assert_eq!(liquidity.min_liquidity_msat(), 400);
2064 assert_eq!(liquidity.max_liquidity_msat(), 800);
2066 let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2067 .as_directed(&target, &source, 0, 1_000, decay_params);
2068 assert_eq!(liquidity.min_liquidity_msat(), 200);
2069 assert_eq!(liquidity.max_liquidity_msat(), 600);
2071 // Reset from source to target.
2072 scorer.channel_liquidities.get_mut(&42).unwrap()
2073 .as_directed_mut(&source, &target, 0, 1_000, decay_params)
2074 .set_max_liquidity_msat(300);
2076 let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2077 .as_directed(&source, &target, 0, 1_000, decay_params);
2078 assert_eq!(liquidity.min_liquidity_msat(), 0);
2079 assert_eq!(liquidity.max_liquidity_msat(), 300);
2081 let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2082 .as_directed(&target, &source, 0, 1_000, decay_params);
2083 assert_eq!(liquidity.min_liquidity_msat(), 700);
2084 assert_eq!(liquidity.max_liquidity_msat(), 1_000);
2086 // Reset from target to source.
2087 scorer.channel_liquidities.get_mut(&42).unwrap()
2088 .as_directed_mut(&target, &source, 0, 1_000, decay_params)
2089 .set_max_liquidity_msat(600);
2091 let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2092 .as_directed(&source, &target, 0, 1_000, decay_params);
2093 assert_eq!(liquidity.min_liquidity_msat(), 400);
2094 assert_eq!(liquidity.max_liquidity_msat(), 1_000);
2096 let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2097 .as_directed(&target, &source, 0, 1_000, decay_params);
2098 assert_eq!(liquidity.min_liquidity_msat(), 0);
2099 assert_eq!(liquidity.max_liquidity_msat(), 600);
2103 fn increased_penalty_nearing_liquidity_upper_bound() {
2104 let logger = TestLogger::new();
2105 let network_graph = network_graph(&logger);
2106 let params = ProbabilisticScoringFeeParameters {
2107 liquidity_penalty_multiplier_msat: 1_000,
2108 ..ProbabilisticScoringFeeParameters::zero_penalty()
2110 let decay_params = ProbabilisticScoringDecayParameters::default();
2111 let scorer = ProbabilisticScorer::new(decay_params, &network_graph, &logger);
2112 let source = source_node_id();
2113 let target = target_node_id();
2115 let usage = ChannelUsage {
2117 inflight_htlc_msat: 0,
2118 effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024_000, htlc_maximum_msat: 1_000 },
2120 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 0);
2121 let usage = ChannelUsage { amount_msat: 10_240, ..usage };
2122 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 0);
2123 let usage = ChannelUsage { amount_msat: 102_400, ..usage };
2124 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 47);
2125 let usage = ChannelUsage { amount_msat: 1_023_999, ..usage };
2126 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 2_000);
2128 let usage = ChannelUsage {
2130 inflight_htlc_msat: 0,
2131 effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024, htlc_maximum_msat: 1_000 },
2133 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 58);
2134 let usage = ChannelUsage { amount_msat: 256, ..usage };
2135 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 125);
2136 let usage = ChannelUsage { amount_msat: 374, ..usage };
2137 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 198);
2138 let usage = ChannelUsage { amount_msat: 512, ..usage };
2139 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 300);
2140 let usage = ChannelUsage { amount_msat: 640, ..usage };
2141 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 425);
2142 let usage = ChannelUsage { amount_msat: 768, ..usage };
2143 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 602);
2144 let usage = ChannelUsage { amount_msat: 896, ..usage };
2145 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 902);
2149 fn constant_penalty_outside_liquidity_bounds() {
2150 let logger = TestLogger::new();
2151 let last_updated = SinceEpoch::now();
2152 let network_graph = network_graph(&logger);
2153 let params = ProbabilisticScoringFeeParameters {
2154 liquidity_penalty_multiplier_msat: 1_000,
2155 considered_impossible_penalty_msat: u64::max_value(),
2156 ..ProbabilisticScoringFeeParameters::zero_penalty()
2158 let decay_params = ProbabilisticScoringDecayParameters {
2159 ..ProbabilisticScoringDecayParameters::zero_penalty()
2161 let scorer = ProbabilisticScorer::new(decay_params, &network_graph, &logger)
2164 min_liquidity_offset_msat: 40, max_liquidity_offset_msat: 40, last_updated,
2165 min_liquidity_offset_history: HistoricalBucketRangeTracker::new(),
2166 max_liquidity_offset_history: HistoricalBucketRangeTracker::new(),
2168 let source = source_node_id();
2169 let target = target_node_id();
2171 let usage = ChannelUsage {
2173 inflight_htlc_msat: 0,
2174 effective_capacity: EffectiveCapacity::Total { capacity_msat: 100, htlc_maximum_msat: 1_000 },
2176 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 0);
2177 let usage = ChannelUsage { amount_msat: 50, ..usage };
2178 assert_ne!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 0);
2179 assert_ne!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), u64::max_value());
2180 let usage = ChannelUsage { amount_msat: 61, ..usage };
2181 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), u64::max_value());
2185 fn does_not_further_penalize_own_channel() {
2186 let logger = TestLogger::new();
2187 let network_graph = network_graph(&logger);
2188 let params = ProbabilisticScoringFeeParameters {
2189 liquidity_penalty_multiplier_msat: 1_000,
2190 ..ProbabilisticScoringFeeParameters::zero_penalty()
2192 let mut scorer = ProbabilisticScorer::new(ProbabilisticScoringDecayParameters::default(), &network_graph, &logger);
2193 let sender = sender_node_id();
2194 let source = source_node_id();
2195 let usage = ChannelUsage {
2197 inflight_htlc_msat: 0,
2198 effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_000, htlc_maximum_msat: 1_000 },
2200 let failed_path = payment_path_for_amount(500);
2201 let successful_path = payment_path_for_amount(200);
2203 assert_eq!(scorer.channel_penalty_msat(41, &sender, &source, usage, ¶ms), 301);
2205 scorer.payment_path_failed(&failed_path, 41);
2206 assert_eq!(scorer.channel_penalty_msat(41, &sender, &source, usage, ¶ms), 301);
2208 scorer.payment_path_successful(&successful_path);
2209 assert_eq!(scorer.channel_penalty_msat(41, &sender, &source, usage, ¶ms), 301);
2213 fn sets_liquidity_lower_bound_on_downstream_failure() {
2214 let logger = TestLogger::new();
2215 let network_graph = network_graph(&logger);
2216 let params = ProbabilisticScoringFeeParameters {
2217 liquidity_penalty_multiplier_msat: 1_000,
2218 ..ProbabilisticScoringFeeParameters::zero_penalty()
2220 let mut scorer = ProbabilisticScorer::new(ProbabilisticScoringDecayParameters::default(), &network_graph, &logger);
2221 let source = source_node_id();
2222 let target = target_node_id();
2223 let path = payment_path_for_amount(500);
2225 let usage = ChannelUsage {
2227 inflight_htlc_msat: 0,
2228 effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_000, htlc_maximum_msat: 1_000 },
2230 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 128);
2231 let usage = ChannelUsage { amount_msat: 500, ..usage };
2232 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 301);
2233 let usage = ChannelUsage { amount_msat: 750, ..usage };
2234 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 602);
2236 scorer.payment_path_failed(&path, 43);
2238 let usage = ChannelUsage { amount_msat: 250, ..usage };
2239 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 0);
2240 let usage = ChannelUsage { amount_msat: 500, ..usage };
2241 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 0);
2242 let usage = ChannelUsage { amount_msat: 750, ..usage };
2243 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 300);
2247 fn sets_liquidity_upper_bound_on_failure() {
2248 let logger = TestLogger::new();
2249 let network_graph = network_graph(&logger);
2250 let params = ProbabilisticScoringFeeParameters {
2251 liquidity_penalty_multiplier_msat: 1_000,
2252 considered_impossible_penalty_msat: u64::max_value(),
2253 ..ProbabilisticScoringFeeParameters::zero_penalty()
2255 let mut scorer = ProbabilisticScorer::new(ProbabilisticScoringDecayParameters::default(), &network_graph, &logger);
2256 let source = source_node_id();
2257 let target = target_node_id();
2258 let path = payment_path_for_amount(500);
2260 let usage = ChannelUsage {
2262 inflight_htlc_msat: 0,
2263 effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_000, htlc_maximum_msat: 1_000 },
2265 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 128);
2266 let usage = ChannelUsage { amount_msat: 500, ..usage };
2267 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 301);
2268 let usage = ChannelUsage { amount_msat: 750, ..usage };
2269 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 602);
2271 scorer.payment_path_failed(&path, 42);
2273 let usage = ChannelUsage { amount_msat: 250, ..usage };
2274 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 300);
2275 let usage = ChannelUsage { amount_msat: 500, ..usage };
2276 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), u64::max_value());
2277 let usage = ChannelUsage { amount_msat: 750, ..usage };
2278 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), u64::max_value());
2282 fn ignores_channels_after_removed_failed_channel() {
2283 // Previously, if we'd tried to send over a channel which was removed from the network
2284 // graph before we call `payment_path_failed` (which is the default if the we get a "no
2285 // such channel" error in the `InvoicePayer`), we would call `failed_downstream` on all
2286 // channels in the route, even ones which they payment never reached. This tests to ensure
2287 // we do not score such channels.
2288 let secp_ctx = Secp256k1::new();
2289 let logger = TestLogger::new();
2290 let mut network_graph = NetworkGraph::new(Network::Testnet, &logger);
2291 let secret_a = SecretKey::from_slice(&[42; 32]).unwrap();
2292 let secret_b = SecretKey::from_slice(&[43; 32]).unwrap();
2293 let secret_c = SecretKey::from_slice(&[44; 32]).unwrap();
2294 let secret_d = SecretKey::from_slice(&[45; 32]).unwrap();
2295 add_channel(&mut network_graph, 42, secret_a, secret_b);
2296 // Don't add the channel from B -> C.
2297 add_channel(&mut network_graph, 44, secret_c, secret_d);
2299 let pub_a = PublicKey::from_secret_key(&secp_ctx, &secret_a);
2300 let pub_b = PublicKey::from_secret_key(&secp_ctx, &secret_b);
2301 let pub_c = PublicKey::from_secret_key(&secp_ctx, &secret_c);
2302 let pub_d = PublicKey::from_secret_key(&secp_ctx, &secret_d);
2305 path_hop(pub_b, 42, 1),
2306 path_hop(pub_c, 43, 2),
2307 path_hop(pub_d, 44, 100),
2310 let node_a = NodeId::from_pubkey(&pub_a);
2311 let node_b = NodeId::from_pubkey(&pub_b);
2312 let node_c = NodeId::from_pubkey(&pub_c);
2313 let node_d = NodeId::from_pubkey(&pub_d);
2315 let params = ProbabilisticScoringFeeParameters {
2316 liquidity_penalty_multiplier_msat: 1_000,
2317 ..ProbabilisticScoringFeeParameters::zero_penalty()
2319 let mut scorer = ProbabilisticScorer::new(ProbabilisticScoringDecayParameters::default(), &network_graph, &logger);
2321 let usage = ChannelUsage {
2323 inflight_htlc_msat: 0,
2324 effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_000, htlc_maximum_msat: 1_000 },
2326 assert_eq!(scorer.channel_penalty_msat(42, &node_a, &node_b, usage, ¶ms), 128);
2327 // Note that a default liquidity bound is used for B -> C as no channel exists
2328 assert_eq!(scorer.channel_penalty_msat(43, &node_b, &node_c, usage, ¶ms), 128);
2329 assert_eq!(scorer.channel_penalty_msat(44, &node_c, &node_d, usage, ¶ms), 128);
2331 scorer.payment_path_failed(&Path { hops: path, blinded_tail: None }, 43);
2333 assert_eq!(scorer.channel_penalty_msat(42, &node_a, &node_b, usage, ¶ms), 80);
2334 // Note that a default liquidity bound is used for B -> C as no channel exists
2335 assert_eq!(scorer.channel_penalty_msat(43, &node_b, &node_c, usage, ¶ms), 128);
2336 assert_eq!(scorer.channel_penalty_msat(44, &node_c, &node_d, usage, ¶ms), 128);
2340 fn reduces_liquidity_upper_bound_along_path_on_success() {
2341 let logger = TestLogger::new();
2342 let network_graph = network_graph(&logger);
2343 let params = ProbabilisticScoringFeeParameters {
2344 liquidity_penalty_multiplier_msat: 1_000,
2345 ..ProbabilisticScoringFeeParameters::zero_penalty()
2347 let mut scorer = ProbabilisticScorer::new(ProbabilisticScoringDecayParameters::default(), &network_graph, &logger);
2348 let sender = sender_node_id();
2349 let source = source_node_id();
2350 let target = target_node_id();
2351 let recipient = recipient_node_id();
2352 let usage = ChannelUsage {
2354 inflight_htlc_msat: 0,
2355 effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_000, htlc_maximum_msat: 1_000 },
2358 assert_eq!(scorer.channel_penalty_msat(41, &sender, &source, usage, ¶ms), 128);
2359 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 128);
2360 assert_eq!(scorer.channel_penalty_msat(43, &target, &recipient, usage, ¶ms), 128);
2362 scorer.payment_path_successful(&payment_path_for_amount(500));
2364 assert_eq!(scorer.channel_penalty_msat(41, &sender, &source, usage, ¶ms), 128);
2365 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 300);
2366 assert_eq!(scorer.channel_penalty_msat(43, &target, &recipient, usage, ¶ms), 300);
2370 fn decays_liquidity_bounds_over_time() {
2371 let logger = TestLogger::new();
2372 let network_graph = network_graph(&logger);
2373 let params = ProbabilisticScoringFeeParameters {
2374 liquidity_penalty_multiplier_msat: 1_000,
2375 considered_impossible_penalty_msat: u64::max_value(),
2376 ..ProbabilisticScoringFeeParameters::zero_penalty()
2378 let decay_params = ProbabilisticScoringDecayParameters {
2379 liquidity_offset_half_life: Duration::from_secs(10),
2380 ..ProbabilisticScoringDecayParameters::zero_penalty()
2382 let mut scorer = ProbabilisticScorer::new(decay_params, &network_graph, &logger);
2383 let source = source_node_id();
2384 let target = target_node_id();
2386 let usage = ChannelUsage {
2388 inflight_htlc_msat: 0,
2389 effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024, htlc_maximum_msat: 1_024 },
2391 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 0);
2392 let usage = ChannelUsage { amount_msat: 1_023, ..usage };
2393 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 2_000);
2395 scorer.payment_path_failed(&payment_path_for_amount(768), 42);
2396 scorer.payment_path_failed(&payment_path_for_amount(128), 43);
2398 let usage = ChannelUsage { amount_msat: 128, ..usage };
2399 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 0);
2400 let usage = ChannelUsage { amount_msat: 256, ..usage };
2401 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 93);
2402 let usage = ChannelUsage { amount_msat: 768, ..usage };
2403 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 1_479);
2404 let usage = ChannelUsage { amount_msat: 896, ..usage };
2405 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), u64::max_value());
2407 SinceEpoch::advance(Duration::from_secs(9));
2408 let usage = ChannelUsage { amount_msat: 128, ..usage };
2409 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 0);
2410 let usage = ChannelUsage { amount_msat: 256, ..usage };
2411 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 93);
2412 let usage = ChannelUsage { amount_msat: 768, ..usage };
2413 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 1_479);
2414 let usage = ChannelUsage { amount_msat: 896, ..usage };
2415 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), u64::max_value());
2417 SinceEpoch::advance(Duration::from_secs(1));
2418 let usage = ChannelUsage { amount_msat: 64, ..usage };
2419 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 0);
2420 let usage = ChannelUsage { amount_msat: 128, ..usage };
2421 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 34);
2422 let usage = ChannelUsage { amount_msat: 896, ..usage };
2423 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 1_970);
2424 let usage = ChannelUsage { amount_msat: 960, ..usage };
2425 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), u64::max_value());
2427 // Fully decay liquidity lower bound.
2428 SinceEpoch::advance(Duration::from_secs(10 * 7));
2429 let usage = ChannelUsage { amount_msat: 0, ..usage };
2430 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 0);
2431 let usage = ChannelUsage { amount_msat: 1, ..usage };
2432 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 0);
2433 let usage = ChannelUsage { amount_msat: 1_023, ..usage };
2434 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 2_000);
2435 let usage = ChannelUsage { amount_msat: 1_024, ..usage };
2436 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), u64::max_value());
2438 // Fully decay liquidity upper bound.
2439 SinceEpoch::advance(Duration::from_secs(10));
2440 let usage = ChannelUsage { amount_msat: 0, ..usage };
2441 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 0);
2442 let usage = ChannelUsage { amount_msat: 1_024, ..usage };
2443 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), u64::max_value());
2445 SinceEpoch::advance(Duration::from_secs(10));
2446 let usage = ChannelUsage { amount_msat: 0, ..usage };
2447 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 0);
2448 let usage = ChannelUsage { amount_msat: 1_024, ..usage };
2449 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), u64::max_value());
2453 fn decays_liquidity_bounds_without_shift_overflow() {
2454 let logger = TestLogger::new();
2455 let network_graph = network_graph(&logger);
2456 let params = ProbabilisticScoringFeeParameters {
2457 liquidity_penalty_multiplier_msat: 1_000,
2458 ..ProbabilisticScoringFeeParameters::zero_penalty()
2460 let decay_params = ProbabilisticScoringDecayParameters {
2461 liquidity_offset_half_life: Duration::from_secs(10),
2462 ..ProbabilisticScoringDecayParameters::default()
2464 let mut scorer = ProbabilisticScorer::new(decay_params, &network_graph, &logger);
2465 let source = source_node_id();
2466 let target = target_node_id();
2467 let usage = ChannelUsage {
2469 inflight_htlc_msat: 0,
2470 effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024, htlc_maximum_msat: 1_000 },
2472 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 125);
2474 scorer.payment_path_failed(&payment_path_for_amount(512), 42);
2475 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 281);
2477 // An unchecked right shift 64 bits or more in DirectedChannelLiquidity::decayed_offset_msat
2478 // would cause an overflow.
2479 SinceEpoch::advance(Duration::from_secs(10 * 64));
2480 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 125);
2482 SinceEpoch::advance(Duration::from_secs(10));
2483 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 125);
2487 fn restricts_liquidity_bounds_after_decay() {
2488 let logger = TestLogger::new();
2489 let network_graph = network_graph(&logger);
2490 let params = ProbabilisticScoringFeeParameters {
2491 liquidity_penalty_multiplier_msat: 1_000,
2492 ..ProbabilisticScoringFeeParameters::zero_penalty()
2494 let decay_params = ProbabilisticScoringDecayParameters {
2495 liquidity_offset_half_life: Duration::from_secs(10),
2496 ..ProbabilisticScoringDecayParameters::default()
2498 let mut scorer = ProbabilisticScorer::new(decay_params, &network_graph, &logger);
2499 let source = source_node_id();
2500 let target = target_node_id();
2501 let usage = ChannelUsage {
2503 inflight_htlc_msat: 0,
2504 effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024, htlc_maximum_msat: 1_000 },
2507 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 300);
2509 // More knowledge gives higher confidence (256, 768), meaning a lower penalty.
2510 scorer.payment_path_failed(&payment_path_for_amount(768), 42);
2511 scorer.payment_path_failed(&payment_path_for_amount(256), 43);
2512 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 281);
2514 // Decaying knowledge gives less confidence (128, 896), meaning a higher penalty.
2515 SinceEpoch::advance(Duration::from_secs(10));
2516 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 291);
2518 // Reducing the upper bound gives more confidence (128, 832) that the payment amount (512)
2519 // is closer to the upper bound, meaning a higher penalty.
2520 scorer.payment_path_successful(&payment_path_for_amount(64));
2521 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 331);
2523 // Increasing the lower bound gives more confidence (256, 832) that the payment amount (512)
2524 // is closer to the lower bound, meaning a lower penalty.
2525 scorer.payment_path_failed(&payment_path_for_amount(256), 43);
2526 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 245);
2528 // Further decaying affects the lower bound more than the upper bound (128, 928).
2529 SinceEpoch::advance(Duration::from_secs(10));
2530 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 280);
2534 fn restores_persisted_liquidity_bounds() {
2535 let logger = TestLogger::new();
2536 let network_graph = network_graph(&logger);
2537 let params = ProbabilisticScoringFeeParameters {
2538 liquidity_penalty_multiplier_msat: 1_000,
2539 considered_impossible_penalty_msat: u64::max_value(),
2540 ..ProbabilisticScoringFeeParameters::zero_penalty()
2542 let decay_params = ProbabilisticScoringDecayParameters {
2543 liquidity_offset_half_life: Duration::from_secs(10),
2544 ..ProbabilisticScoringDecayParameters::default()
2546 let mut scorer = ProbabilisticScorer::new(decay_params, &network_graph, &logger);
2547 let source = source_node_id();
2548 let target = target_node_id();
2549 let usage = ChannelUsage {
2551 inflight_htlc_msat: 0,
2552 effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_000, htlc_maximum_msat: 1_000 },
2555 scorer.payment_path_failed(&payment_path_for_amount(500), 42);
2556 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), u64::max_value());
2558 SinceEpoch::advance(Duration::from_secs(10));
2559 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 473);
2561 scorer.payment_path_failed(&payment_path_for_amount(250), 43);
2562 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 300);
2564 let mut serialized_scorer = Vec::new();
2565 scorer.write(&mut serialized_scorer).unwrap();
2567 let mut serialized_scorer = io::Cursor::new(&serialized_scorer);
2568 let deserialized_scorer =
2569 <ProbabilisticScorer>::read(&mut serialized_scorer, (decay_params, &network_graph, &logger)).unwrap();
2570 assert_eq!(deserialized_scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 300);
2574 fn decays_persisted_liquidity_bounds() {
2575 let logger = TestLogger::new();
2576 let network_graph = network_graph(&logger);
2577 let params = ProbabilisticScoringFeeParameters {
2578 liquidity_penalty_multiplier_msat: 1_000,
2579 considered_impossible_penalty_msat: u64::max_value(),
2580 ..ProbabilisticScoringFeeParameters::zero_penalty()
2582 let decay_params = ProbabilisticScoringDecayParameters {
2583 liquidity_offset_half_life: Duration::from_secs(10),
2584 ..ProbabilisticScoringDecayParameters::zero_penalty()
2586 let mut scorer = ProbabilisticScorer::new(decay_params, &network_graph, &logger);
2587 let source = source_node_id();
2588 let target = target_node_id();
2589 let usage = ChannelUsage {
2591 inflight_htlc_msat: 0,
2592 effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_000, htlc_maximum_msat: 1_000 },
2595 scorer.payment_path_failed(&payment_path_for_amount(500), 42);
2596 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), u64::max_value());
2598 let mut serialized_scorer = Vec::new();
2599 scorer.write(&mut serialized_scorer).unwrap();
2601 SinceEpoch::advance(Duration::from_secs(10));
2603 let mut serialized_scorer = io::Cursor::new(&serialized_scorer);
2604 let deserialized_scorer =
2605 <ProbabilisticScorer>::read(&mut serialized_scorer, (decay_params, &network_graph, &logger)).unwrap();
2606 assert_eq!(deserialized_scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 473);
2608 scorer.payment_path_failed(&payment_path_for_amount(250), 43);
2609 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 300);
2611 SinceEpoch::advance(Duration::from_secs(10));
2612 assert_eq!(deserialized_scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 365);
2616 fn scores_realistic_payments() {
2617 // Shows the scores of "realistic" sends of 100k sats over channels of 1-10m sats (with a
2618 // 50k sat reserve).
2619 let logger = TestLogger::new();
2620 let network_graph = network_graph(&logger);
2621 let params = ProbabilisticScoringFeeParameters::default();
2622 let scorer = ProbabilisticScorer::new(ProbabilisticScoringDecayParameters::default(), &network_graph, &logger);
2623 let source = source_node_id();
2624 let target = target_node_id();
2626 let usage = ChannelUsage {
2627 amount_msat: 100_000_000,
2628 inflight_htlc_msat: 0,
2629 effective_capacity: EffectiveCapacity::Total { capacity_msat: 950_000_000, htlc_maximum_msat: 1_000 },
2631 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 4375);
2632 let usage = ChannelUsage {
2633 effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_950_000_000, htlc_maximum_msat: 1_000 }, ..usage
2635 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 2739);
2636 let usage = ChannelUsage {
2637 effective_capacity: EffectiveCapacity::Total { capacity_msat: 2_950_000_000, htlc_maximum_msat: 1_000 }, ..usage
2639 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 2236);
2640 let usage = ChannelUsage {
2641 effective_capacity: EffectiveCapacity::Total { capacity_msat: 3_950_000_000, htlc_maximum_msat: 1_000 }, ..usage
2643 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 1983);
2644 let usage = ChannelUsage {
2645 effective_capacity: EffectiveCapacity::Total { capacity_msat: 4_950_000_000, htlc_maximum_msat: 1_000 }, ..usage
2647 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 1637);
2648 let usage = ChannelUsage {
2649 effective_capacity: EffectiveCapacity::Total { capacity_msat: 5_950_000_000, htlc_maximum_msat: 1_000 }, ..usage
2651 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 1606);
2652 let usage = ChannelUsage {
2653 effective_capacity: EffectiveCapacity::Total { capacity_msat: 6_950_000_000, htlc_maximum_msat: 1_000 }, ..usage
2655 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 1331);
2656 let usage = ChannelUsage {
2657 effective_capacity: EffectiveCapacity::Total { capacity_msat: 7_450_000_000, htlc_maximum_msat: 1_000 }, ..usage
2659 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 1387);
2660 let usage = ChannelUsage {
2661 effective_capacity: EffectiveCapacity::Total { capacity_msat: 7_950_000_000, htlc_maximum_msat: 1_000 }, ..usage
2663 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 1379);
2664 let usage = ChannelUsage {
2665 effective_capacity: EffectiveCapacity::Total { capacity_msat: 8_950_000_000, htlc_maximum_msat: 1_000 }, ..usage
2667 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 1363);
2668 let usage = ChannelUsage {
2669 effective_capacity: EffectiveCapacity::Total { capacity_msat: 9_950_000_000, htlc_maximum_msat: 1_000 }, ..usage
2671 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 1355);
2675 fn adds_base_penalty_to_liquidity_penalty() {
2676 let logger = TestLogger::new();
2677 let network_graph = network_graph(&logger);
2678 let source = source_node_id();
2679 let target = target_node_id();
2680 let usage = ChannelUsage {
2682 inflight_htlc_msat: 0,
2683 effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024, htlc_maximum_msat: 1_000 },
2686 let params = ProbabilisticScoringFeeParameters {
2687 liquidity_penalty_multiplier_msat: 1_000,
2688 ..ProbabilisticScoringFeeParameters::zero_penalty()
2690 let scorer = ProbabilisticScorer::new(ProbabilisticScoringDecayParameters::default(), &network_graph, &logger);
2691 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 58);
2693 let params = ProbabilisticScoringFeeParameters {
2694 base_penalty_msat: 500, liquidity_penalty_multiplier_msat: 1_000,
2695 anti_probing_penalty_msat: 0, ..ProbabilisticScoringFeeParameters::zero_penalty()
2697 let scorer = ProbabilisticScorer::new(ProbabilisticScoringDecayParameters::default(), &network_graph, &logger);
2698 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 558);
2700 let params = ProbabilisticScoringFeeParameters {
2701 base_penalty_msat: 500, liquidity_penalty_multiplier_msat: 1_000,
2702 base_penalty_amount_multiplier_msat: (1 << 30),
2703 anti_probing_penalty_msat: 0, ..ProbabilisticScoringFeeParameters::zero_penalty()
2706 let scorer = ProbabilisticScorer::new(ProbabilisticScoringDecayParameters::default(), &network_graph, &logger);
2707 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 558 + 128);
2711 fn adds_amount_penalty_to_liquidity_penalty() {
2712 let logger = TestLogger::new();
2713 let network_graph = network_graph(&logger);
2714 let source = source_node_id();
2715 let target = target_node_id();
2716 let usage = ChannelUsage {
2717 amount_msat: 512_000,
2718 inflight_htlc_msat: 0,
2719 effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024_000, htlc_maximum_msat: 1_000 },
2722 let params = ProbabilisticScoringFeeParameters {
2723 liquidity_penalty_multiplier_msat: 1_000,
2724 liquidity_penalty_amount_multiplier_msat: 0,
2725 ..ProbabilisticScoringFeeParameters::zero_penalty()
2727 let scorer = ProbabilisticScorer::new(ProbabilisticScoringDecayParameters::default(), &network_graph, &logger);
2728 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 300);
2730 let params = ProbabilisticScoringFeeParameters {
2731 liquidity_penalty_multiplier_msat: 1_000,
2732 liquidity_penalty_amount_multiplier_msat: 256,
2733 ..ProbabilisticScoringFeeParameters::zero_penalty()
2735 let scorer = ProbabilisticScorer::new(ProbabilisticScoringDecayParameters::default(), &network_graph, &logger);
2736 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 337);
2740 fn calculates_log10_without_overflowing_u64_max_value() {
2741 let logger = TestLogger::new();
2742 let network_graph = network_graph(&logger);
2743 let source = source_node_id();
2744 let target = target_node_id();
2745 let usage = ChannelUsage {
2746 amount_msat: u64::max_value(),
2747 inflight_htlc_msat: 0,
2748 effective_capacity: EffectiveCapacity::Infinite,
2751 let params = ProbabilisticScoringFeeParameters {
2752 liquidity_penalty_multiplier_msat: 40_000,
2753 ..ProbabilisticScoringFeeParameters::zero_penalty()
2755 let decay_params = ProbabilisticScoringDecayParameters::zero_penalty();
2756 let scorer = ProbabilisticScorer::new(decay_params, &network_graph, &logger);
2757 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 80_000);
2761 fn accounts_for_inflight_htlc_usage() {
2762 let logger = TestLogger::new();
2763 let network_graph = network_graph(&logger);
2764 let params = ProbabilisticScoringFeeParameters {
2765 considered_impossible_penalty_msat: u64::max_value(),
2766 ..ProbabilisticScoringFeeParameters::zero_penalty()
2768 let scorer = ProbabilisticScorer::new(ProbabilisticScoringDecayParameters::default(), &network_graph, &logger);
2769 let source = source_node_id();
2770 let target = target_node_id();
2772 let usage = ChannelUsage {
2774 inflight_htlc_msat: 0,
2775 effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_000, htlc_maximum_msat: 1_000 },
2777 assert_ne!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), u64::max_value());
2779 let usage = ChannelUsage { inflight_htlc_msat: 251, ..usage };
2780 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), u64::max_value());
2784 fn removes_uncertainity_when_exact_liquidity_known() {
2785 let logger = TestLogger::new();
2786 let network_graph = network_graph(&logger);
2787 let params = ProbabilisticScoringFeeParameters::default();
2788 let scorer = ProbabilisticScorer::new(ProbabilisticScoringDecayParameters::default(), &network_graph, &logger);
2789 let source = source_node_id();
2790 let target = target_node_id();
2792 let base_penalty_msat = params.base_penalty_msat;
2793 let usage = ChannelUsage {
2795 inflight_htlc_msat: 0,
2796 effective_capacity: EffectiveCapacity::ExactLiquidity { liquidity_msat: 1_000 },
2798 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), base_penalty_msat);
2800 let usage = ChannelUsage { amount_msat: 1_000, ..usage };
2801 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), base_penalty_msat);
2803 let usage = ChannelUsage { amount_msat: 1_001, ..usage };
2804 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), u64::max_value());
2808 fn remembers_historical_failures() {
2809 let logger = TestLogger::new();
2810 let network_graph = network_graph(&logger);
2811 let params = ProbabilisticScoringFeeParameters {
2812 historical_liquidity_penalty_multiplier_msat: 1024,
2813 historical_liquidity_penalty_amount_multiplier_msat: 1024,
2814 ..ProbabilisticScoringFeeParameters::zero_penalty()
2816 let decay_params = ProbabilisticScoringDecayParameters {
2817 liquidity_offset_half_life: Duration::from_secs(60 * 60),
2818 historical_no_updates_half_life: Duration::from_secs(10),
2820 let mut scorer = ProbabilisticScorer::new(decay_params, &network_graph, &logger);
2821 let source = source_node_id();
2822 let target = target_node_id();
2824 let usage = ChannelUsage {
2826 inflight_htlc_msat: 0,
2827 effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024, htlc_maximum_msat: 1_024 },
2829 // With no historical data the normal liquidity penalty calculation is used.
2830 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 47);
2831 assert_eq!(scorer.historical_estimated_channel_liquidity_probabilities(42, &target),
2834 scorer.payment_path_failed(&payment_path_for_amount(1), 42);
2835 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 2048);
2836 // The "it failed" increment is 32, where the probability should lie fully in the first
2838 assert_eq!(scorer.historical_estimated_channel_liquidity_probabilities(42, &target),
2839 Some(([32, 0, 0, 0, 0, 0, 0, 0], [32, 0, 0, 0, 0, 0, 0, 0])));
2841 // Even after we tell the scorer we definitely have enough available liquidity, it will
2842 // still remember that there was some failure in the past, and assign a non-0 penalty.
2843 scorer.payment_path_failed(&payment_path_for_amount(1000), 43);
2844 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 198);
2845 // The first octile should be decayed just slightly and the last octile has a new point.
2846 assert_eq!(scorer.historical_estimated_channel_liquidity_probabilities(42, &target),
2847 Some(([31, 0, 0, 0, 0, 0, 0, 32], [31, 0, 0, 0, 0, 0, 0, 32])));
2849 // Advance the time forward 16 half-lives (which the docs claim will ensure all data is
2850 // gone), and check that we're back to where we started.
2851 SinceEpoch::advance(Duration::from_secs(10 * 16));
2852 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 47);
2853 // Once fully decayed we still have data, but its all-0s. In the future we may remove the
2854 // data entirely instead.
2855 assert_eq!(scorer.historical_estimated_channel_liquidity_probabilities(42, &target),
2856 Some(([0; 8], [0; 8])));
2858 let usage = ChannelUsage {
2860 inflight_htlc_msat: 1024,
2861 effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024, htlc_maximum_msat: 1_024 },
2863 scorer.payment_path_failed(&payment_path_for_amount(1), 42);
2864 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 409);
2866 let usage = ChannelUsage {
2868 inflight_htlc_msat: 0,
2869 effective_capacity: EffectiveCapacity::MaximumHTLC { amount_msat: 0 },
2871 assert_eq!(scorer.channel_penalty_msat(42, &target, &source, usage, ¶ms), 2048);
2873 // Advance to decay all liquidity offsets to zero.
2874 SinceEpoch::advance(Duration::from_secs(60 * 60 * 10));
2876 // Use a path in the opposite direction, which have zero for htlc_maximum_msat. This will
2877 // ensure that the effective capacity is zero to test division-by-zero edge cases.
2879 path_hop(target_pubkey(), 43, 2),
2880 path_hop(source_pubkey(), 42, 1),
2881 path_hop(sender_pubkey(), 41, 0),
2883 scorer.payment_path_failed(&Path { hops: path, blinded_tail: None }, 42);
2887 fn adds_anti_probing_penalty() {
2888 let logger = TestLogger::new();
2889 let network_graph = network_graph(&logger);
2890 let source = source_node_id();
2891 let target = target_node_id();
2892 let params = ProbabilisticScoringFeeParameters {
2893 anti_probing_penalty_msat: 500,
2894 ..ProbabilisticScoringFeeParameters::zero_penalty()
2896 let scorer = ProbabilisticScorer::new(ProbabilisticScoringDecayParameters::default(), &network_graph, &logger);
2898 // Check we receive no penalty for a low htlc_maximum_msat.
2899 let usage = ChannelUsage {
2900 amount_msat: 512_000,
2901 inflight_htlc_msat: 0,
2902 effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024_000, htlc_maximum_msat: 1_000 },
2904 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 0);
2906 // Check we receive anti-probing penalty for htlc_maximum_msat == channel_capacity.
2907 let usage = ChannelUsage {
2908 amount_msat: 512_000,
2909 inflight_htlc_msat: 0,
2910 effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024_000, htlc_maximum_msat: 1_024_000 },
2912 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 500);
2914 // Check we receive anti-probing penalty for htlc_maximum_msat == channel_capacity/2.
2915 let usage = ChannelUsage {
2916 amount_msat: 512_000,
2917 inflight_htlc_msat: 0,
2918 effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024_000, htlc_maximum_msat: 512_000 },
2920 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 500);
2922 // Check we receive no anti-probing penalty for htlc_maximum_msat == channel_capacity/2 - 1.
2923 let usage = ChannelUsage {
2924 amount_msat: 512_000,
2925 inflight_htlc_msat: 0,
2926 effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024_000, htlc_maximum_msat: 511_999 },
2928 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 0);
2932 fn scores_with_blinded_path() {
2933 // Make sure we'll account for a blinded path's final_value_msat in scoring
2934 let logger = TestLogger::new();
2935 let network_graph = network_graph(&logger);
2936 let params = ProbabilisticScoringFeeParameters {
2937 liquidity_penalty_multiplier_msat: 1_000,
2938 ..ProbabilisticScoringFeeParameters::zero_penalty()
2940 let decay_params = ProbabilisticScoringDecayParameters::default();
2941 let mut scorer = ProbabilisticScorer::new(decay_params, &network_graph, &logger);
2942 let source = source_node_id();
2943 let target = target_node_id();
2944 let usage = ChannelUsage {
2946 inflight_htlc_msat: 0,
2947 effective_capacity: EffectiveCapacity::Total { capacity_msat: 1_024, htlc_maximum_msat: 1_000 },
2949 assert_eq!(scorer.channel_penalty_msat(42, &source, &target, usage, ¶ms), 300);
2951 let mut path = payment_path_for_amount(768);
2952 let recipient_hop = path.hops.pop().unwrap();
2953 let blinded_path = BlindedPath {
2954 introduction_node_id: path.hops.last().as_ref().unwrap().pubkey,
2955 blinding_point: test_utils::pubkey(42),
2957 BlindedHop { blinded_node_id: test_utils::pubkey(44), encrypted_payload: Vec::new() }
2960 path.blinded_tail = Some(BlindedTail {
2961 hops: blinded_path.blinded_hops,
2962 blinding_point: blinded_path.blinding_point,
2963 excess_final_cltv_expiry_delta: recipient_hop.cltv_expiry_delta,
2964 final_value_msat: recipient_hop.fee_msat,
2967 // Check the liquidity before and after scoring payment failures to ensure the blinded path's
2968 // final value is taken into account.
2969 assert!(scorer.channel_liquidities.get(&42).is_none());
2971 scorer.payment_path_failed(&path, 42);
2972 path.blinded_tail.as_mut().unwrap().final_value_msat = 256;
2973 scorer.payment_path_failed(&path, 43);
2975 let liquidity = scorer.channel_liquidities.get(&42).unwrap()
2976 .as_directed(&source, &target, 0, 1_000, decay_params);
2977 assert_eq!(liquidity.min_liquidity_msat(), 256);
2978 assert_eq!(liquidity.max_liquidity_msat(), 768);