_ Git - rust-lightning/blob - lightning/src/routing/scoring.rs

   1 // This file is Copyright its original authors, visible in version control
   2 // history.
   3 //
   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
   8 // licenses.
   9
  10 //! Utilities for scoring payment channels.
  11 //!
  12 //! [`Scorer`] may be given to [`find_route`] to score payment channels during path finding when a
  13 //! custom [`Score`] implementation is not needed.
  14 //!
  15 //! # Example
  16 //!
  17 //! ```
  18 //! # extern crate secp256k1;
  19 //! #
  20 //! # use lightning::routing::network_graph::NetworkGraph;
  21 //! # use lightning::routing::router::{RouteParameters, find_route};
  22 //! # use lightning::routing::scoring::{Scorer, ScoringParameters};
  23 //! # use lightning::util::logger::{Logger, Record};
  24 //! # use secp256k1::key::PublicKey;
  25 //! #
  26 //! # struct FakeLogger {};
  27 //! # impl Logger for FakeLogger {
  28 //! #     fn log(&self, record: &Record) { unimplemented!() }
  29 //! # }
  30 //! # fn find_scored_route(payer: PublicKey, params: RouteParameters, network_graph: NetworkGraph) {
  31 //! # let logger = FakeLogger {};
  32 //! #
  33 //! // Use the default channel penalties.
  34 //! let scorer = Scorer::default();
  35 //!
  36 //! // Or use custom channel penalties.
  37 //! let scorer = Scorer::new(ScoringParameters {
  38 //!     base_penalty_msat: 1000,
  39 //!     failure_penalty_msat: 2 * 1024 * 1000,
  40 //!     ..ScoringParameters::default()
  41 //! });
  42 //!
  43 //! let route = find_route(&payer, &params, &network_graph, None, &logger, &scorer);
  44 //! # }
  45 //! ```
  46 //!
  47 //! # Note
  48 //!
  49 //! Persisting when built with feature `no-std` and restoring without it, or vice versa, uses
  50 //! different types and thus is undefined.
  51 //!
  52 //! [`find_route`]: crate::routing::router::find_route
  53
  54 use ln::msgs::DecodeError;
  55 use routing::network_graph::NodeId;
  56 use routing::router::RouteHop;
  57 use util::ser::{Readable, Writeable, Writer};
  58
  59 use prelude::*;
  60 use core::cell::{RefCell, RefMut};
  61 use core::ops::DerefMut;
  62 use core::time::Duration;
  63 use io::{self, Read};
  64 use sync::{Mutex, MutexGuard};
  65
  66 /// We define Score ever-so-slightly differently based on whether we are being built for C bindings
  67 /// or not. For users, `LockableScore` must somehow be writeable to disk. For Rust users, this is
  68 /// no problem - you move a `Score` that implements `Writeable` into a `Mutex`, lock it, and now
  69 /// you have the original, concrete, `Score` type, which presumably implements `Writeable`.
  70 ///
  71 /// For C users, once you've moved the `Score` into a `LockableScore` all you have after locking it
  72 /// is an opaque trait object with an opaque pointer with no type info. Users could take the unsafe
  73 /// approach of blindly casting that opaque pointer to a concrete type and calling `Writeable` from
  74 /// there, but other languages downstream of the C bindings (e.g. Java) can't even do that.
  75 /// Instead, we really want `Score` and `LockableScore` to implement `Writeable` directly, which we
  76 /// do here by defining `Score` differently for `cfg(c_bindings)`.
  77 macro_rules! define_score { ($($supertrait: path)*) => {
  78 /// An interface used to score payment channels for path finding.
  79 ///
  80 ///     Scoring is in terms of fees willing to be paid in order to avoid routing through a channel.
  81 pub trait Score $(: $supertrait)* {
  82         /// Returns the fee in msats willing to be paid to avoid routing `send_amt_msat` through the
  83         /// given channel in the direction from `source` to `target`.
  84         ///
  85         /// The channel's capacity (less any other MPP parts which are also being considered for use in
  86         /// the same payment) is given by `channel_capacity_msat`. It may be guessed from various
  87         /// sources or assumed from no data at all.
  88         ///
  89         /// For hints provided in the invoice, we assume the channel has sufficient capacity to accept
  90         /// the invoice's full amount, and provide a `channel_capacity_msat` of `None`. In all other
  91         /// cases it is set to `Some`, even if we're guessing at the channel value.
  92         ///
  93         /// Your code should be overflow-safe through a `channel_capacity_msat` of 21 million BTC.
  94         fn channel_penalty_msat(&self, short_channel_id: u64, send_amt_msat: u64, channel_capacity_msat: Option<u64>, source: &NodeId, target: &NodeId) -> u64;
  95
  96         /// Handles updating channel penalties after failing to route through a channel.
  97         fn payment_path_failed(&mut self, path: &[&RouteHop], short_channel_id: u64);
  98
  99         /// Handles updating channel penalties after successfully routing along a path.
 100         fn payment_path_successful(&mut self, path: &[&RouteHop]);
 101 }
 102
 103 impl<S: Score, T: DerefMut<Target=S> $(+ $supertrait)*> Score for T {
 104         fn channel_penalty_msat(&self, short_channel_id: u64, send_amt_msat: u64, channel_capacity_msat: Option<u64>, source: &NodeId, target: &NodeId) -> u64 {
 105                 self.deref().channel_penalty_msat(short_channel_id, send_amt_msat, channel_capacity_msat, source, target)
 106         }
 107
 108         fn payment_path_failed(&mut self, path: &[&RouteHop], short_channel_id: u64) {
 109                 self.deref_mut().payment_path_failed(path, short_channel_id)
 110         }
 111
 112         fn payment_path_successful(&mut self, path: &[&RouteHop]) {
 113                 self.deref_mut().payment_path_successful(path)
 114         }
 115 }
 116 } }
 117
 118 #[cfg(c_bindings)]
 119 define_score!(Writeable);
 120 #[cfg(not(c_bindings))]
 121 define_score!();
 122
 123 /// A scorer that is accessed under a lock.
 124 ///
 125 /// Needed so that calls to [`Score::channel_penalty_msat`] in [`find_route`] can be made while
 126 /// having shared ownership of a scorer but without requiring internal locking in [`Score`]
 127 /// implementations. Internal locking would be detrimental to route finding performance and could
 128 /// result in [`Score::channel_penalty_msat`] returning a different value for the same channel.
 129 ///
 130 /// [`find_route`]: crate::routing::router::find_route
 131 pub trait LockableScore<'a> {
 132         /// The locked [`Score`] type.
 133         type Locked: 'a + Score;
 134
 135         /// Returns the locked scorer.
 136         fn lock(&'a self) -> Self::Locked;
 137 }
 138
 139 /// (C-not exported)
 140 impl<'a, T: 'a + Score> LockableScore<'a> for Mutex<T> {
 141         type Locked = MutexGuard<'a, T>;
 142
 143         fn lock(&'a self) -> MutexGuard<'a, T> {
 144                 Mutex::lock(self).unwrap()
 145         }
 146 }
 147
 148 impl<'a, T: 'a + Score> LockableScore<'a> for RefCell<T> {
 149         type Locked = RefMut<'a, T>;
 150
 151         fn lock(&'a self) -> RefMut<'a, T> {
 152                 self.borrow_mut()
 153         }
 154 }
 155
 156 #[cfg(c_bindings)]
 157 /// A concrete implementation of [`LockableScore`] which supports multi-threading.
 158 pub struct MultiThreadedLockableScore<S: Score> {
 159         score: Mutex<S>,
 160 }
 161 #[cfg(c_bindings)]
 162 /// (C-not exported)
 163 impl<'a, T: Score + 'a> LockableScore<'a> for MultiThreadedLockableScore<T> {
 164         type Locked = MutexGuard<'a, T>;
 165
 166         fn lock(&'a self) -> MutexGuard<'a, T> {
 167                 Mutex::lock(&self.score).unwrap()
 168         }
 169 }
 170
 171 #[cfg(c_bindings)]
 172 /// (C-not exported)
 173 impl<'a, T: Writeable> Writeable for RefMut<'a, T> {
 174         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 175                 T::write(&**self, writer)
 176         }
 177 }
 178
 179 #[cfg(c_bindings)]
 180 /// (C-not exported)
 181 impl<'a, S: Writeable> Writeable for MutexGuard<'a, S> {
 182         fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 183                 S::write(&**self, writer)
 184         }
 185 }
 186
 187 /// [`Score`] implementation that provides reasonable default behavior.
 188 ///
 189 /// Used to apply a fixed penalty to each channel, thus avoiding long paths when shorter paths with
 190 /// slightly higher fees are available. Will further penalize channels that fail to relay payments.
 191 ///
 192 /// See [module-level documentation] for usage.
 193 ///
 194 /// [module-level documentation]: crate::routing::scoring
 195 #[cfg(not(feature = "no-std"))]
 196 pub type Scorer = ScorerUsingTime::<std::time::Instant>;
 197 /// [`Score`] implementation that provides reasonable default behavior.
 198 ///
 199 /// Used to apply a fixed penalty to each channel, thus avoiding long paths when shorter paths with
 200 /// slightly higher fees are available. Will further penalize channels that fail to relay payments.
 201 ///
 202 /// See [module-level documentation] for usage.
 203 ///
 204 /// [module-level documentation]: crate::routing::scoring
 205 #[cfg(feature = "no-std")]
 206 pub type Scorer = ScorerUsingTime::<time::Eternity>;
 207
 208 // Note that ideally we'd hide ScorerUsingTime from public view by sealing it as well, but rustdoc
 209 // doesn't handle this well - instead exposing a `Scorer` which has no trait implementation(s) or
 210 // methods at all.
 211
 212 /// [`Score`] implementation.
 213 ///
 214 /// See [`Scorer`] for details.
 215 ///
 216 /// # Note
 217 ///
 218 /// Mixing the `no-std` feature between serialization and deserialization results in undefined
 219 /// behavior.
 220 ///
 221 /// (C-not exported) generally all users should use the [`Scorer`] type alias.
 222 pub struct ScorerUsingTime<T: Time> {
 223         params: ScoringParameters,
 224         // TODO: Remove entries of closed channels.
 225         channel_failures: HashMap<u64, ChannelFailure<T>>,
 226 }
 227
 228 /// Parameters for configuring [`Scorer`].
 229 pub struct ScoringParameters {
 230         /// A fixed penalty in msats to apply to each channel.
 231         ///
 232         /// Default value: 500 msat
 233         pub base_penalty_msat: u64,
 234
 235         /// A penalty in msats to apply to a channel upon failing to relay a payment.
 236         ///
 237         /// This accumulates for each failure but may be reduced over time based on
 238         /// [`failure_penalty_half_life`].
 239         ///
 240         /// Default value: 1,024,000 msat
 241         ///
 242         /// [`failure_penalty_half_life`]: Self::failure_penalty_half_life
 243         pub failure_penalty_msat: u64,
 244
 245         /// When the amount being sent over a channel is this many 1024ths of the total channel
 246         /// capacity, we begin applying [`overuse_penalty_msat_per_1024th`].
 247         ///
 248         /// Default value: 128 1024ths (i.e. begin penalizing when an HTLC uses 1/8th of a channel)
 249         ///
 250         /// [`overuse_penalty_msat_per_1024th`]: Self::overuse_penalty_msat_per_1024th
 251         pub overuse_penalty_start_1024th: u16,
 252
 253         /// A penalty applied, per whole 1024ths of the channel capacity which the amount being sent
 254         /// over the channel exceeds [`overuse_penalty_start_1024th`] by.
 255         ///
 256         /// Default value: 20 msat (i.e. 2560 msat penalty to use 1/4th of a channel, 7680 msat penalty
 257         ///                to use half a channel, and 12,560 msat penalty to use 3/4ths of a channel)
 258         ///
 259         /// [`overuse_penalty_start_1024th`]: Self::overuse_penalty_start_1024th
 260         pub overuse_penalty_msat_per_1024th: u64,
 261
 262         /// The time required to elapse before any accumulated [`failure_penalty_msat`] penalties are
 263         /// cut in half.
 264         ///
 265         /// # Note
 266         ///
 267         /// When built with the `no-std` feature, time will never elapse. Therefore, this penalty will
 268         /// never decay.
 269         ///
 270         /// [`failure_penalty_msat`]: Self::failure_penalty_msat
 271         pub failure_penalty_half_life: Duration,
 272 }
 273
 274 impl_writeable_tlv_based!(ScoringParameters, {
 275         (0, base_penalty_msat, required),
 276         (1, overuse_penalty_start_1024th, (default_value, 128)),
 277         (2, failure_penalty_msat, required),
 278         (3, overuse_penalty_msat_per_1024th, (default_value, 20)),
 279         (4, failure_penalty_half_life, required),
 280 });
 281
 282 /// Accounting for penalties against a channel for failing to relay any payments.
 283 ///
 284 /// Penalties decay over time, though accumulate as more failures occur.
 285 struct ChannelFailure<T: Time> {
 286         /// Accumulated penalty in msats for the channel as of `last_failed`.
 287         undecayed_penalty_msat: u64,
 288
 289         /// Last time the channel failed. Used to decay `undecayed_penalty_msat`.
 290         last_failed: T,
 291 }
 292
 293 impl<T: Time> ScorerUsingTime<T> {
 294         /// Creates a new scorer using the given scoring parameters.
 295         pub fn new(params: ScoringParameters) -> Self {
 296                 Self {
 297                         params,
 298                         channel_failures: HashMap::new(),
 299                 }
 300         }
 301
 302         /// Creates a new scorer using `penalty_msat` as a fixed channel penalty.
 303         #[cfg(any(test, feature = "fuzztarget", feature = "_test_utils"))]
 304         pub fn with_fixed_penalty(penalty_msat: u64) -> Self {
 305                 Self::new(ScoringParameters {
 306                         base_penalty_msat: penalty_msat,
 307                         failure_penalty_msat: 0,
 308                         failure_penalty_half_life: Duration::from_secs(0),
 309                         overuse_penalty_start_1024th: 1024,
 310                         overuse_penalty_msat_per_1024th: 0,
 311                 })
 312         }
 313 }
 314
 315 impl<T: Time> ChannelFailure<T> {
 316         fn new(failure_penalty_msat: u64) -> Self {
 317                 Self {
 318                         undecayed_penalty_msat: failure_penalty_msat,
 319                         last_failed: T::now(),
 320                 }
 321         }
 322
 323         fn add_penalty(&mut self, failure_penalty_msat: u64, half_life: Duration) {
 324                 self.undecayed_penalty_msat = self.decayed_penalty_msat(half_life) + failure_penalty_msat;
 325                 self.last_failed = T::now();
 326         }
 327
 328         fn decayed_penalty_msat(&self, half_life: Duration) -> u64 {
 329                 let decays = self.last_failed.elapsed().as_secs().checked_div(half_life.as_secs());
 330                 match decays {
 331                         Some(decays) => self.undecayed_penalty_msat >> decays,
 332                         None => 0,
 333                 }
 334         }
 335 }
 336
 337 impl<T: Time> Default for ScorerUsingTime<T> {
 338         fn default() -> Self {
 339                 Self::new(ScoringParameters::default())
 340         }
 341 }
 342
 343 impl Default for ScoringParameters {
 344         fn default() -> Self {
 345                 Self {
 346                         base_penalty_msat: 500,
 347                         failure_penalty_msat: 1024 * 1000,
 348                         failure_penalty_half_life: Duration::from_secs(3600),
 349                         overuse_penalty_start_1024th: 1024 / 8,
 350                         overuse_penalty_msat_per_1024th: 20,
 351                 }
 352         }
 353 }
 354
 355 impl<T: Time> Score for ScorerUsingTime<T> {
 356         fn channel_penalty_msat(
 357                 &self, short_channel_id: u64, send_amt_msat: u64, chan_capacity_opt: Option<u64>, _source: &NodeId, _target: &NodeId
 358         ) -> u64 {
 359                 let failure_penalty_msat = self.channel_failures
 360                         .get(&short_channel_id)
 361                         .map_or(0, |value| value.decayed_penalty_msat(self.params.failure_penalty_half_life));
 362
 363                 let mut penalty_msat = self.params.base_penalty_msat + failure_penalty_msat;
 364
 365                 if let Some(chan_capacity_msat) = chan_capacity_opt {
 366                         let send_1024ths = send_amt_msat.checked_mul(1024).unwrap_or(u64::max_value()) / chan_capacity_msat;
 367
 368                         if send_1024ths > self.params.overuse_penalty_start_1024th as u64 {
 369                                 penalty_msat = penalty_msat.checked_add(
 370                                                 (send_1024ths - self.params.overuse_penalty_start_1024th as u64)
 371                                                 .checked_mul(self.params.overuse_penalty_msat_per_1024th).unwrap_or(u64::max_value()))
 372                                         .unwrap_or(u64::max_value());
 373                         }
 374                 }
 375
 376                 penalty_msat
 377         }
 378
 379         fn payment_path_failed(&mut self, _path: &[&RouteHop], short_channel_id: u64) {
 380                 let failure_penalty_msat = self.params.failure_penalty_msat;
 381                 let half_life = self.params.failure_penalty_half_life;
 382                 self.channel_failures
 383                         .entry(short_channel_id)
 384                         .and_modify(|failure| failure.add_penalty(failure_penalty_msat, half_life))
 385                         .or_insert_with(|| ChannelFailure::new(failure_penalty_msat));
 386         }
 387
 388         fn payment_path_successful(&mut self, _path: &[&RouteHop]) {}
 389 }
 390
 391 impl<T: Time> Writeable for ScorerUsingTime<T> {
 392         #[inline]
 393         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
 394                 self.params.write(w)?;
 395                 self.channel_failures.write(w)?;
 396                 write_tlv_fields!(w, {});
 397                 Ok(())
 398         }
 399 }
 400
 401 impl<T: Time> Readable for ScorerUsingTime<T> {
 402         #[inline]
 403         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
 404                 let res = Ok(Self {
 405                         params: Readable::read(r)?,
 406                         channel_failures: Readable::read(r)?,
 407                 });
 408                 read_tlv_fields!(r, {});
 409                 res
 410         }
 411 }
 412
 413 impl<T: Time> Writeable for ChannelFailure<T> {
 414         #[inline]
 415         fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
 416                 let duration_since_epoch = T::duration_since_epoch() - self.last_failed.elapsed();
 417                 write_tlv_fields!(w, {
 418                         (0, self.undecayed_penalty_msat, required),
 419                         (2, duration_since_epoch, required),
 420                 });
 421                 Ok(())
 422         }
 423 }
 424
 425 impl<T: Time> Readable for ChannelFailure<T> {
 426         #[inline]
 427         fn read<R: Read>(r: &mut R) -> Result<Self, DecodeError> {
 428                 let mut undecayed_penalty_msat = 0;
 429                 let mut duration_since_epoch = Duration::from_secs(0);
 430                 read_tlv_fields!(r, {
 431                         (0, undecayed_penalty_msat, required),
 432                         (2, duration_since_epoch, required),
 433                 });
 434                 Ok(Self {
 435                         undecayed_penalty_msat,
 436                         last_failed: T::now() - (T::duration_since_epoch() - duration_since_epoch),
 437                 })
 438         }
 439 }
 440
 441 pub(crate) mod time {
 442         use core::ops::Sub;
 443         use core::time::Duration;
 444         /// A measurement of time.
 445         pub trait Time: Sub<Duration, Output = Self> where Self: Sized {
 446                 /// Returns an instance corresponding to the current moment.
 447                 fn now() -> Self;
 448
 449                 /// Returns the amount of time elapsed since `self` was created.
 450                 fn elapsed(&self) -> Duration;
 451
 452                 /// Returns the amount of time passed since the beginning of [`Time`].
 453                 ///
 454                 /// Used during (de-)serialization.
 455                 fn duration_since_epoch() -> Duration;
 456         }
 457
 458         /// A state in which time has no meaning.
 459         #[derive(Debug, PartialEq, Eq)]
 460         pub struct Eternity;
 461
 462         #[cfg(not(feature = "no-std"))]
 463         impl Time for std::time::Instant {
 464                 fn now() -> Self {
 465                         std::time::Instant::now()
 466                 }
 467
 468                 fn duration_since_epoch() -> Duration {
 469                         use std::time::SystemTime;
 470                         SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap()
 471                 }
 472
 473                 fn elapsed(&self) -> Duration {
 474                         std::time::Instant::elapsed(self)
 475                 }
 476         }
 477
 478         impl Time for Eternity {
 479                 fn now() -> Self {
 480                         Self
 481                 }
 482
 483                 fn duration_since_epoch() -> Duration {
 484                         Duration::from_secs(0)
 485                 }
 486
 487                 fn elapsed(&self) -> Duration {
 488                         Duration::from_secs(0)
 489                 }
 490         }
 491
 492         impl Sub<Duration> for Eternity {
 493                 type Output = Self;
 494
 495                 fn sub(self, _other: Duration) -> Self {
 496                         self
 497                 }
 498         }
 499 }
 500
 501 pub(crate) use self::time::Time;
 502
 503 #[cfg(test)]
 504 mod tests {
 505         use super::{ScoringParameters, ScorerUsingTime, Time};
 506         use super::time::Eternity;
 507
 508         use routing::scoring::Score;
 509         use routing::network_graph::NodeId;
 510         use util::ser::{Readable, Writeable};
 511
 512         use bitcoin::secp256k1::PublicKey;
 513         use core::cell::Cell;
 514         use core::ops::Sub;
 515         use core::time::Duration;
 516         use io;
 517
 518         /// Time that can be advanced manually in tests.
 519         #[derive(Debug, PartialEq, Eq)]
 520         struct SinceEpoch(Duration);
 521
 522         impl SinceEpoch {
 523                 thread_local! {
 524                         static ELAPSED: Cell<Duration> = core::cell::Cell::new(Duration::from_secs(0));
 525                 }
 526
 527                 fn advance(duration: Duration) {
 528                         Self::ELAPSED.with(|elapsed| elapsed.set(elapsed.get() + duration))
 529                 }
 530         }
 531
 532         impl Time for SinceEpoch {
 533                 fn now() -> Self {
 534                         Self(Self::duration_since_epoch())
 535                 }
 536
 537                 fn duration_since_epoch() -> Duration {
 538                         Self::ELAPSED.with(|elapsed| elapsed.get())
 539                 }
 540
 541                 fn elapsed(&self) -> Duration {
 542                         Self::duration_since_epoch() - self.0
 543                 }
 544         }
 545
 546         impl Sub<Duration> for SinceEpoch {
 547                 type Output = Self;
 548
 549                 fn sub(self, other: Duration) -> Self {
 550                         Self(self.0 - other)
 551                 }
 552         }
 553
 554         #[test]
 555         fn time_passes_when_advanced() {
 556                 let now = SinceEpoch::now();
 557                 assert_eq!(now.elapsed(), Duration::from_secs(0));
 558
 559                 SinceEpoch::advance(Duration::from_secs(1));
 560                 SinceEpoch::advance(Duration::from_secs(1));
 561
 562                 let elapsed = now.elapsed();
 563                 let later = SinceEpoch::now();
 564
 565                 assert_eq!(elapsed, Duration::from_secs(2));
 566                 assert_eq!(later - elapsed, now);
 567         }
 568
 569         #[test]
 570         fn time_never_passes_in_an_eternity() {
 571                 let now = Eternity::now();
 572                 let elapsed = now.elapsed();
 573                 let later = Eternity::now();
 574
 575                 assert_eq!(now.elapsed(), Duration::from_secs(0));
 576                 assert_eq!(later - elapsed, now);
 577         }
 578
 579         /// A scorer for testing with time that can be manually advanced.
 580         type Scorer = ScorerUsingTime::<SinceEpoch>;
 581
 582         fn source_node_id() -> NodeId {
 583                 NodeId::from_pubkey(&PublicKey::from_slice(&hex::decode("02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619").unwrap()[..]).unwrap())
 584         }
 585
 586         fn target_node_id() -> NodeId {
 587                 NodeId::from_pubkey(&PublicKey::from_slice(&hex::decode("0324653eac434488002cc06bbfb7f10fe18991e35f9fe4302dbea6d2353dc0ab1c").unwrap()[..]).unwrap())
 588         }
 589
 590         #[test]
 591         fn penalizes_without_channel_failures() {
 592                 let scorer = Scorer::new(ScoringParameters {
 593                         base_penalty_msat: 1_000,
 594                         failure_penalty_msat: 512,
 595                         failure_penalty_half_life: Duration::from_secs(1),
 596                         overuse_penalty_start_1024th: 1024,
 597                         overuse_penalty_msat_per_1024th: 0,
 598                 });
 599                 let source = source_node_id();
 600                 let target = target_node_id();
 601                 assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_000);
 602
 603                 SinceEpoch::advance(Duration::from_secs(1));
 604                 assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_000);
 605         }
 606
 607         #[test]
 608         fn accumulates_channel_failure_penalties() {
 609                 let mut scorer = Scorer::new(ScoringParameters {
 610                         base_penalty_msat: 1_000,
 611                         failure_penalty_msat: 64,
 612                         failure_penalty_half_life: Duration::from_secs(10),
 613                         overuse_penalty_start_1024th: 1024,
 614                         overuse_penalty_msat_per_1024th: 0,
 615                 });
 616                 let source = source_node_id();
 617                 let target = target_node_id();
 618                 assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_000);
 619
 620                 scorer.payment_path_failed(&[], 42);
 621                 assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_064);
 622
 623                 scorer.payment_path_failed(&[], 42);
 624                 assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_128);
 625
 626                 scorer.payment_path_failed(&[], 42);
 627                 assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_192);
 628         }
 629
 630         #[test]
 631         fn decays_channel_failure_penalties_over_time() {
 632                 let mut scorer = Scorer::new(ScoringParameters {
 633                         base_penalty_msat: 1_000,
 634                         failure_penalty_msat: 512,
 635                         failure_penalty_half_life: Duration::from_secs(10),
 636                         overuse_penalty_start_1024th: 1024,
 637                         overuse_penalty_msat_per_1024th: 0,
 638                 });
 639                 let source = source_node_id();
 640                 let target = target_node_id();
 641                 assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_000);
 642
 643                 scorer.payment_path_failed(&[], 42);
 644                 assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_512);
 645
 646                 SinceEpoch::advance(Duration::from_secs(9));
 647                 assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_512);
 648
 649                 SinceEpoch::advance(Duration::from_secs(1));
 650                 assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_256);
 651
 652                 SinceEpoch::advance(Duration::from_secs(10 * 8));
 653                 assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_001);
 654
 655                 SinceEpoch::advance(Duration::from_secs(10));
 656                 assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_000);
 657
 658                 SinceEpoch::advance(Duration::from_secs(10));
 659                 assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_000);
 660         }
 661
 662         #[test]
 663         fn accumulates_channel_failure_penalties_after_decay() {
 664                 let mut scorer = Scorer::new(ScoringParameters {
 665                         base_penalty_msat: 1_000,
 666                         failure_penalty_msat: 512,
 667                         failure_penalty_half_life: Duration::from_secs(10),
 668                         overuse_penalty_start_1024th: 1024,
 669                         overuse_penalty_msat_per_1024th: 0,
 670                 });
 671                 let source = source_node_id();
 672                 let target = target_node_id();
 673                 assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_000);
 674
 675                 scorer.payment_path_failed(&[], 42);
 676                 assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_512);
 677
 678                 SinceEpoch::advance(Duration::from_secs(10));
 679                 assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_256);
 680
 681                 scorer.payment_path_failed(&[], 42);
 682                 assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_768);
 683
 684                 SinceEpoch::advance(Duration::from_secs(10));
 685                 assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_384);
 686         }
 687
 688         #[test]
 689         fn restores_persisted_channel_failure_penalties() {
 690                 let mut scorer = Scorer::new(ScoringParameters {
 691                         base_penalty_msat: 1_000,
 692                         failure_penalty_msat: 512,
 693                         failure_penalty_half_life: Duration::from_secs(10),
 694                         overuse_penalty_start_1024th: 1024,
 695                         overuse_penalty_msat_per_1024th: 0,
 696                 });
 697                 let source = source_node_id();
 698                 let target = target_node_id();
 699
 700                 scorer.payment_path_failed(&[], 42);
 701                 assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_512);
 702
 703                 SinceEpoch::advance(Duration::from_secs(10));
 704                 assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_256);
 705
 706                 scorer.payment_path_failed(&[], 43);
 707                 assert_eq!(scorer.channel_penalty_msat(43, 1, Some(1), &source, &target), 1_512);
 708
 709                 let mut serialized_scorer = Vec::new();
 710                 scorer.write(&mut serialized_scorer).unwrap();
 711
 712                 let deserialized_scorer = <Scorer>::read(&mut io::Cursor::new(&serialized_scorer)).unwrap();
 713                 assert_eq!(deserialized_scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_256);
 714                 assert_eq!(deserialized_scorer.channel_penalty_msat(43, 1, Some(1), &source, &target), 1_512);
 715         }
 716
 717         #[test]
 718         fn decays_persisted_channel_failure_penalties() {
 719                 let mut scorer = Scorer::new(ScoringParameters {
 720                         base_penalty_msat: 1_000,
 721                         failure_penalty_msat: 512,
 722                         failure_penalty_half_life: Duration::from_secs(10),
 723                         overuse_penalty_start_1024th: 1024,
 724                         overuse_penalty_msat_per_1024th: 0,
 725                 });
 726                 let source = source_node_id();
 727                 let target = target_node_id();
 728
 729                 scorer.payment_path_failed(&[], 42);
 730                 assert_eq!(scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_512);
 731
 732                 let mut serialized_scorer = Vec::new();
 733                 scorer.write(&mut serialized_scorer).unwrap();
 734
 735                 SinceEpoch::advance(Duration::from_secs(10));
 736
 737                 let deserialized_scorer = <Scorer>::read(&mut io::Cursor::new(&serialized_scorer)).unwrap();
 738                 assert_eq!(deserialized_scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_256);
 739
 740                 SinceEpoch::advance(Duration::from_secs(10));
 741                 assert_eq!(deserialized_scorer.channel_penalty_msat(42, 1, Some(1), &source, &target), 1_128);
 742         }
 743
 744         #[test]
 745         fn charges_per_1024th_penalty() {
 746                 let scorer = Scorer::new(ScoringParameters {
 747                         base_penalty_msat: 0,
 748                         failure_penalty_msat: 0,
 749                         failure_penalty_half_life: Duration::from_secs(0),
 750                         overuse_penalty_start_1024th: 256,
 751                         overuse_penalty_msat_per_1024th: 100,
 752                 });
 753                 let source = source_node_id();
 754                 let target = target_node_id();
 755
 756                 assert_eq!(scorer.channel_penalty_msat(42, 1_000, None, &source, &target), 0);
 757                 assert_eq!(scorer.channel_penalty_msat(42, 1_000, Some(1_024_000), &source, &target), 0);
 758                 assert_eq!(scorer.channel_penalty_msat(42, 256_999, Some(1_024_000), &source, &target), 0);
 759                 assert_eq!(scorer.channel_penalty_msat(42, 257_000, Some(1_024_000), &source, &target), 100);
 760                 assert_eq!(scorer.channel_penalty_msat(42, 258_000, Some(1_024_000), &source, &target), 200);
 761                 assert_eq!(scorer.channel_penalty_msat(42, 512_000, Some(1_024_000), &source, &target), 256 * 100);
 762         }
 763 }