git.bitcoin.ninja Git - rust-lightning/blob - lightning-invoice/src/payment.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 //! A module for paying Lightning invoices.
  11 //!
  12 //! Defines an [`InvoicePayer`] utility for paying invoices, parameterized by [`Payer`] and
  13 //! [`Router`] traits. Implementations of [`Payer`] provide the payer's node id, channels, and means
  14 //! to send a payment over a [`Route`]. Implementations of [`Router`] find a [`Route`] between payer
  15 //! and payee using information provided by the payer and from the payee's [`Invoice`].
  16 //!
  17 //! [`InvoicePayer`] is capable of retrying failed payments. It accomplishes this by implementing
  18 //! [`EventHandler`] which decorates a user-provided handler. It will intercept any
  19 //! [`Event::PaymentPathFailed`] events and retry the failed paths for a fixed number of total
  20 //! attempts or until retry is no longer possible. In such a situation, [`InvoicePayer`] will pass
  21 //! along the events to the user-provided handler.
  22 //!
  23 //! # Example
  24 //!
  25 //! ```
  26 //! # extern crate lightning;
  27 //! # extern crate lightning_invoice;
  28 //! # extern crate secp256k1;
  29 //! #
  30 //! # use lightning::ln::{PaymentHash, PaymentSecret};
  31 //! # use lightning::ln::channelmanager::{ChannelDetails, PaymentId, PaymentSendFailure};
  32 //! # use lightning::ln::msgs::LightningError;
  33 //! # use lightning::routing;
  34 //! # use lightning::routing::network_graph::NodeId;
  35 //! # use lightning::routing::router::{Route, RouteHop, RouteParameters};
  36 //! # use lightning::util::events::{Event, EventHandler, EventsProvider};
  37 //! # use lightning::util::logger::{Logger, Record};
  38 //! # use lightning_invoice::Invoice;
  39 //! # use lightning_invoice::payment::{InvoicePayer, Payer, RetryAttempts, Router};
  40 //! # use secp256k1::key::PublicKey;
  41 //! # use std::cell::RefCell;
  42 //! # use std::ops::Deref;
  43 //! #
  44 //! # struct FakeEventProvider {}
  45 //! # impl EventsProvider for FakeEventProvider {
  46 //! #     fn process_pending_events<H: Deref>(&self, handler: H) where H::Target: EventHandler {}
  47 //! # }
  48 //! #
  49 //! # struct FakePayer {}
  50 //! # impl Payer for FakePayer {
  51 //! #     fn node_id(&self) -> PublicKey { unimplemented!() }
  52 //! #     fn first_hops(&self) -> Vec<ChannelDetails> { unimplemented!() }
  53 //! #     fn send_payment(
  54 //! #         &self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>
  55 //! #     ) -> Result<PaymentId, PaymentSendFailure> { unimplemented!() }
  56 //! #     fn retry_payment(
  57 //! #         &self, route: &Route, payment_id: PaymentId
  58 //! #     ) -> Result<(), PaymentSendFailure> { unimplemented!() }
  59 //! # }
  60 //! #
  61 //! # struct FakeRouter {};
  62 //! # impl<S: routing::Score> Router<S> for FakeRouter {
  63 //! #     fn find_route(
  64 //! #         &self, payer: &PublicKey, params: &RouteParameters,
  65 //! #         first_hops: Option<&[&ChannelDetails]>, scorer: &S
  66 //! #     ) -> Result<Route, LightningError> { unimplemented!() }
  67 //! # }
  68 //! #
  69 //! # struct FakeScorer {};
  70 //! # impl routing::Score for FakeScorer {
  71 //! #     fn channel_penalty_msat(
  72 //! #         &self, _short_channel_id: u64, _source: &NodeId, _target: &NodeId
  73 //! #     ) -> u64 { 0 }
  74 //! #     fn payment_path_failed(&mut self, _path: &Vec<RouteHop>, _short_channel_id: u64) {}
  75 //! # }
  76 //! #
  77 //! # struct FakeLogger {};
  78 //! # impl Logger for FakeLogger {
  79 //! #     fn log(&self, record: &Record) { unimplemented!() }
  80 //! # }
  81 //! #
  82 //! # fn main() {
  83 //! let event_handler = |event: &Event| {
  84 //!     match event {
  85 //!         Event::PaymentPathFailed { .. } => println!("payment failed after retries"),
  86 //!         Event::PaymentSent { .. } => println!("payment successful"),
  87 //!         _ => {},
  88 //!     }
  89 //! };
  90 //! # let payer = FakePayer {};
  91 //! # let router = FakeRouter {};
  92 //! # let scorer = RefCell::new(FakeScorer {});
  93 //! # let logger = FakeLogger {};
  94 //! let invoice_payer = InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
  95 //!
  96 //! let invoice = "...";
  97 //! let invoice = invoice.parse::<Invoice>().unwrap();
  98 //! invoice_payer.pay_invoice(&invoice).unwrap();
  99 //!
 100 //! # let event_provider = FakeEventProvider {};
 101 //! loop {
 102 //!     event_provider.process_pending_events(&invoice_payer);
 103 //! }
 104 //! # }
 105 //! ```
 106 //!
 107 //! # Note
 108 //!
 109 //! The [`Route`] is computed before each payment attempt. Any updates affecting path finding such
 110 //! as updates to the network graph or changes to channel scores should be applied prior to
 111 //! retries, typically by way of composing [`EventHandler`]s accordingly.
 112
 113 use crate::Invoice;
 114
 115 use bitcoin_hashes::Hash;
 116
 117 use lightning::ln::{PaymentHash, PaymentSecret};
 118 use lightning::ln::channelmanager::{ChannelDetails, PaymentId, PaymentSendFailure};
 119 use lightning::ln::msgs::LightningError;
 120 use lightning::routing;
 121 use lightning::routing::{LockableScore, Score};
 122 use lightning::routing::router::{Payee, Route, RouteParameters};
 123 use lightning::util::events::{Event, EventHandler};
 124 use lightning::util::logger::Logger;
 125
 126 use secp256k1::key::PublicKey;
 127
 128 use std::collections::hash_map::{self, HashMap};
 129 use std::ops::Deref;
 130 use std::sync::Mutex;
 131 use std::time::{Duration, SystemTime};
 132
 133 /// A utility for paying [`Invoice]`s.
 134 pub struct InvoicePayer<P: Deref, R, S: Deref, L: Deref, E>
 135 where
 136         P::Target: Payer,
 137         R: for <'a> Router<<<S as Deref>::Target as routing::LockableScore<'a>>::Locked>,
 138         S::Target: for <'a> routing::LockableScore<'a>,
 139         L::Target: Logger,
 140         E: EventHandler,
 141 {
 142         payer: P,
 143         router: R,
 144         scorer: S,
 145         logger: L,
 146         event_handler: E,
 147         payment_cache: Mutex<HashMap<PaymentHash, usize>>,
 148         retry_attempts: RetryAttempts,
 149 }
 150
 151 /// A trait defining behavior of an [`Invoice`] payer.
 152 pub trait Payer {
 153         /// Returns the payer's node id.
 154         fn node_id(&self) -> PublicKey;
 155
 156         /// Returns the payer's channels.
 157         fn first_hops(&self) -> Vec<ChannelDetails>;
 158
 159         /// Sends a payment over the Lightning Network using the given [`Route`].
 160         fn send_payment(
 161                 &self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>
 162         ) -> Result<PaymentId, PaymentSendFailure>;
 163
 164         /// Retries a failed payment path for the [`PaymentId`] using the given [`Route`].
 165         fn retry_payment(&self, route: &Route, payment_id: PaymentId) -> Result<(), PaymentSendFailure>;
 166 }
 167
 168 /// A trait defining behavior for routing an [`Invoice`] payment.
 169 pub trait Router<S: routing::Score> {
 170         /// Finds a [`Route`] between `payer` and `payee` for a payment with the given values.
 171         fn find_route(
 172                 &self, payer: &PublicKey, params: &RouteParameters, first_hops: Option<&[&ChannelDetails]>,
 173                 scorer: &S
 174         ) -> Result<Route, LightningError>;
 175 }
 176
 177 /// Number of attempts to retry payment path failures for an [`Invoice`].
 178 ///
 179 /// Note that this is the number of *path* failures, not full payment retries. For multi-path
 180 /// payments, if this is less than the total number of paths, we will never even retry all of the
 181 /// payment's paths.
 182 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
 183 pub struct RetryAttempts(pub usize);
 184
 185 /// An error that may occur when making a payment.
 186 #[derive(Clone, Debug)]
 187 pub enum PaymentError {
 188         /// An error resulting from the provided [`Invoice`] or payment hash.
 189         Invoice(&'static str),
 190         /// An error occurring when finding a route.
 191         Routing(LightningError),
 192         /// An error occurring when sending a payment.
 193         Sending(PaymentSendFailure),
 194 }
 195
 196 impl<P: Deref, R, S: Deref, L: Deref, E> InvoicePayer<P, R, S, L, E>
 197 where
 198         P::Target: Payer,
 199         R: for <'a> Router<<<S as Deref>::Target as routing::LockableScore<'a>>::Locked>,
 200         S::Target: for <'a> routing::LockableScore<'a>,
 201         L::Target: Logger,
 202         E: EventHandler,
 203 {
 204         /// Creates an invoice payer that retries failed payment paths.
 205         ///
 206         /// Will forward any [`Event::PaymentPathFailed`] events to the decorated `event_handler` once
 207         /// `retry_attempts` has been exceeded for a given [`Invoice`].
 208         pub fn new(
 209                 payer: P, router: R, scorer: S, logger: L, event_handler: E, retry_attempts: RetryAttempts
 210         ) -> Self {
 211                 Self {
 212                         payer,
 213                         router,
 214                         scorer,
 215                         logger,
 216                         event_handler,
 217                         payment_cache: Mutex::new(HashMap::new()),
 218                         retry_attempts,
 219                 }
 220         }
 221
 222         /// Pays the given [`Invoice`], caching it for later use in case a retry is needed.
 223         ///
 224         /// You should ensure that the `invoice.payment_hash()` is unique and the same payment_hash has
 225         /// never been paid before. Because [`InvoicePayer`] is stateless no effort is made to do so
 226         /// for you.
 227         pub fn pay_invoice(&self, invoice: &Invoice) -> Result<PaymentId, PaymentError> {
 228                 if invoice.amount_milli_satoshis().is_none() {
 229                         Err(PaymentError::Invoice("amount missing"))
 230                 } else {
 231                         self.pay_invoice_internal(invoice, None, 0)
 232                 }
 233         }
 234
 235         /// Pays the given zero-value [`Invoice`] using the given amount, caching it for later use in
 236         /// case a retry is needed.
 237         ///
 238         /// You should ensure that the `invoice.payment_hash()` is unique and the same payment_hash has
 239         /// never been paid before. Because [`InvoicePayer`] is stateless no effort is made to do so
 240         /// for you.
 241         pub fn pay_zero_value_invoice(
 242                 &self, invoice: &Invoice, amount_msats: u64
 243         ) -> Result<PaymentId, PaymentError> {
 244                 if invoice.amount_milli_satoshis().is_some() {
 245                         Err(PaymentError::Invoice("amount unexpected"))
 246                 } else {
 247                         self.pay_invoice_internal(invoice, Some(amount_msats), 0)
 248                 }
 249         }
 250
 251         fn pay_invoice_internal(
 252                 &self, invoice: &Invoice, amount_msats: Option<u64>, retry_count: usize
 253         ) -> Result<PaymentId, PaymentError> {
 254                 debug_assert!(invoice.amount_milli_satoshis().is_some() ^ amount_msats.is_some());
 255                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 256                 let retry_data_payment_id = loop {
 257                         let mut payment_cache = self.payment_cache.lock().unwrap();
 258                         match payment_cache.entry(payment_hash) {
 259                                 hash_map::Entry::Vacant(entry) => {
 260                                         let payer = self.payer.node_id();
 261                                         let mut payee = Payee::new(invoice.recover_payee_pub_key())
 262                                                 .with_expiry_time(expiry_time_from_unix_epoch(&invoice).as_secs())
 263                                                 .with_route_hints(invoice.route_hints());
 264                                         if let Some(features) = invoice.features() {
 265                                                 payee = payee.with_features(features.clone());
 266                                         }
 267                                         let params = RouteParameters {
 268                                                 payee,
 269                                                 final_value_msat: invoice.amount_milli_satoshis().or(amount_msats).unwrap(),
 270                                                 final_cltv_expiry_delta: invoice.min_final_cltv_expiry() as u32,
 271                                         };
 272                                         let first_hops = self.payer.first_hops();
 273                                         let route = self.router.find_route(
 274                                                 &payer,
 275                                                 &params,
 276                                                 Some(&first_hops.iter().collect::<Vec<_>>()),
 277                                                 &self.scorer.lock(),
 278                                         ).map_err(|e| PaymentError::Routing(e))?;
 279
 280                                         let payment_secret = Some(invoice.payment_secret().clone());
 281                                         let payment_id = match self.payer.send_payment(&route, payment_hash, &payment_secret) {
 282                                                 Ok(payment_id) => payment_id,
 283                                                 Err(PaymentSendFailure::ParameterError(e)) =>
 284                                                         return Err(PaymentError::Sending(PaymentSendFailure::ParameterError(e))),
 285                                                 Err(PaymentSendFailure::PathParameterError(e)) =>
 286                                                         return Err(PaymentError::Sending(PaymentSendFailure::PathParameterError(e))),
 287                                                 Err(PaymentSendFailure::AllFailedRetrySafe(e)) => {
 288                                                         if retry_count >= self.retry_attempts.0 {
 289                                                                 return Err(PaymentError::Sending(PaymentSendFailure::AllFailedRetrySafe(e)))
 290                                                         }
 291                                                         break None;
 292                                                 },
 293                                                 Err(PaymentSendFailure::PartialFailure { results: _, failed_paths_retry, payment_id }) => {
 294                                                         if let Some(retry_data) = failed_paths_retry {
 295                                                                 entry.insert(retry_count);
 296                                                                 break Some((retry_data, payment_id));
 297                                                         } else {
 298                                                                 // This may happen if we send a payment and some paths fail, but
 299                                                                 // only due to a temporary monitor failure or the like, implying
 300                                                                 // they're really in-flight, but we haven't sent the initial
 301                                                                 // HTLC-Add messages yet.
 302                                                                 payment_id
 303                                                         }
 304                                                 },
 305                                         };
 306                                         entry.insert(retry_count);
 307                                         return Ok(payment_id);
 308                                 },
 309                                 hash_map::Entry::Occupied(_) => return Err(PaymentError::Invoice("payment pending")),
 310                         }
 311                 };
 312                 if let Some((retry_data, payment_id)) = retry_data_payment_id {
 313                         // Some paths were sent, even if we failed to send the full MPP value our recipient may
 314                         // misbehave and claim the funds, at which point we have to consider the payment sent,
 315                         // so return `Ok()` here, ignoring any retry errors.
 316                         let _ = self.retry_payment(payment_id, payment_hash, &retry_data);
 317                         Ok(payment_id)
 318                 } else {
 319                         self.pay_invoice_internal(invoice, amount_msats, retry_count + 1)
 320                 }
 321         }
 322
 323         fn retry_payment(&self, payment_id: PaymentId, payment_hash: PaymentHash, params: &RouteParameters)
 324         -> Result<(), ()> {
 325                 let route;
 326                 {
 327                         let mut payment_cache = self.payment_cache.lock().unwrap();
 328                         let entry = loop {
 329                                 let entry = payment_cache.entry(payment_hash);
 330                                 match entry {
 331                                         hash_map::Entry::Occupied(_) => break entry,
 332                                         hash_map::Entry::Vacant(entry) => entry.insert(0),
 333                                 };
 334                         };
 335                         if let hash_map::Entry::Occupied(mut entry) = entry {
 336                                 let max_payment_attempts = self.retry_attempts.0 + 1;
 337                                 let attempts = entry.get_mut();
 338                                 *attempts += 1;
 339
 340                                 if *attempts >= max_payment_attempts {
 341                                         log_trace!(self.logger, "Payment {} exceeded maximum attempts; not retrying (attempts: {})", log_bytes!(payment_hash.0), attempts);
 342                                         return Err(());
 343                                 } else if has_expired(params) {
 344                                         log_trace!(self.logger, "Invoice expired for payment {}; not retrying (attempts: {})", log_bytes!(payment_hash.0), attempts);
 345                                         return Err(());
 346                                 }
 347
 348                                 let payer = self.payer.node_id();
 349                                 let first_hops = self.payer.first_hops();
 350                                 route = self.router.find_route(&payer, &params, Some(&first_hops.iter().collect::<Vec<_>>()), &self.scorer.lock());
 351                                 if route.is_err() {
 352                                         log_trace!(self.logger, "Failed to find a route for payment {}; not retrying (attempts: {})", log_bytes!(payment_hash.0), attempts);
 353                                         return Err(());
 354                                 }
 355                         } else {
 356                                 unreachable!();
 357                         }
 358                 }
 359
 360                 let retry_res = self.payer.retry_payment(&route.unwrap(), payment_id);
 361                 match retry_res {
 362                         Ok(()) => Ok(()),
 363                         Err(PaymentSendFailure::ParameterError(_)) |
 364                         Err(PaymentSendFailure::PathParameterError(_)) => {
 365                                 log_trace!(self.logger, "Failed to retry for payment {} due to bogus route/payment data, not retrying.", log_bytes!(payment_hash.0));
 366                                 return Err(());
 367                         },
 368                         Err(PaymentSendFailure::AllFailedRetrySafe(_)) => {
 369                                 self.retry_payment(payment_id, payment_hash, params)
 370                         },
 371                         Err(PaymentSendFailure::PartialFailure { results: _, failed_paths_retry, .. }) => {
 372                                 if let Some(retry) = failed_paths_retry {
 373                                         self.retry_payment(payment_id, payment_hash, &retry)
 374                                 } else {
 375                                         Ok(())
 376                                 }
 377                         },
 378                 }
 379         }
 380
 381         /// Removes the payment cached by the given payment hash.
 382         ///
 383         /// Should be called once a payment has failed or succeeded if not using [`InvoicePayer`] as an
 384         /// [`EventHandler`]. Otherwise, calling this method is unnecessary.
 385         pub fn remove_cached_payment(&self, payment_hash: &PaymentHash) {
 386                 self.payment_cache.lock().unwrap().remove(payment_hash);
 387         }
 388 }
 389
 390 fn expiry_time_from_unix_epoch(invoice: &Invoice) -> Duration {
 391         invoice.timestamp().duration_since(SystemTime::UNIX_EPOCH).unwrap() + invoice.expiry_time()
 392 }
 393
 394 fn has_expired(params: &RouteParameters) -> bool {
 395         if let Some(expiry_time) = params.payee.expiry_time {
 396                 Invoice::is_expired_from_epoch(&SystemTime::UNIX_EPOCH, Duration::from_secs(expiry_time))
 397         } else { false }
 398 }
 399
 400 impl<P: Deref, R, S: Deref, L: Deref, E> EventHandler for InvoicePayer<P, R, S, L, E>
 401 where
 402         P::Target: Payer,
 403         R: for <'a> Router<<<S as Deref>::Target as routing::LockableScore<'a>>::Locked>,
 404         S::Target: for <'a> routing::LockableScore<'a>,
 405         L::Target: Logger,
 406         E: EventHandler,
 407 {
 408         fn handle_event(&self, event: &Event) {
 409                 match event {
 410                         Event::PaymentPathFailed {
 411                                 all_paths_failed, payment_id, payment_hash, rejected_by_dest, path, short_channel_id, retry, ..
 412                         } => {
 413                                 if let Some(short_channel_id) = short_channel_id {
 414                                         self.scorer.lock().payment_path_failed(path, *short_channel_id);
 415                                 }
 416
 417                                 if *rejected_by_dest {
 418                                         log_trace!(self.logger, "Payment {} rejected by destination; not retrying", log_bytes!(payment_hash.0));
 419                                 } else if payment_id.is_none() {
 420                                         log_trace!(self.logger, "Payment {} has no id; not retrying", log_bytes!(payment_hash.0));
 421                                 } else if let Some(params) = retry {
 422                                         if self.retry_payment(payment_id.unwrap(), *payment_hash, params).is_ok() {
 423                                                 // We retried at least somewhat, don't provide the PaymentPathFailed event to the user.
 424                                                 return;
 425                                         }
 426                                 } else {
 427                                         log_trace!(self.logger, "Payment {} missing retry params; not retrying", log_bytes!(payment_hash.0));
 428                                 }
 429                                 if *all_paths_failed { self.payment_cache.lock().unwrap().remove(payment_hash); }
 430                         },
 431                         Event::PaymentSent { payment_hash, .. } => {
 432                                 let mut payment_cache = self.payment_cache.lock().unwrap();
 433                                 let attempts = payment_cache
 434                                         .remove(payment_hash)
 435                                         .map_or(1, |attempts| attempts + 1);
 436                                 log_trace!(self.logger, "Payment {} succeeded (attempts: {})", log_bytes!(payment_hash.0), attempts);
 437                         },
 438                         _ => {},
 439                 }
 440
 441                 // Delegate to the decorated event handler unless the payment is retried.
 442                 self.event_handler.handle_event(event)
 443         }
 444 }
 445
 446 #[cfg(test)]
 447 mod tests {
 448         use super::*;
 449         use crate::{DEFAULT_EXPIRY_TIME, InvoiceBuilder, Currency};
 450         use bitcoin_hashes::sha256::Hash as Sha256;
 451         use lightning::ln::PaymentPreimage;
 452         use lightning::ln::features::{ChannelFeatures, NodeFeatures};
 453         use lightning::ln::msgs::{ErrorAction, LightningError};
 454         use lightning::routing::network_graph::NodeId;
 455         use lightning::routing::router::{Payee, Route, RouteHop};
 456         use lightning::util::test_utils::TestLogger;
 457         use lightning::util::errors::APIError;
 458         use lightning::util::events::Event;
 459         use secp256k1::{SecretKey, PublicKey, Secp256k1};
 460         use std::cell::RefCell;
 461         use std::time::{SystemTime, Duration};
 462
 463         fn invoice(payment_preimage: PaymentPreimage) -> Invoice {
 464                 let payment_hash = Sha256::hash(&payment_preimage.0);
 465                 let private_key = SecretKey::from_slice(&[42; 32]).unwrap();
 466                 InvoiceBuilder::new(Currency::Bitcoin)
 467                         .description("test".into())
 468                         .payment_hash(payment_hash)
 469                         .payment_secret(PaymentSecret([0; 32]))
 470                         .current_timestamp()
 471                         .min_final_cltv_expiry(144)
 472                         .amount_milli_satoshis(128)
 473                         .build_signed(|hash| {
 474                                 Secp256k1::new().sign_recoverable(hash, &private_key)
 475                         })
 476                         .unwrap()
 477         }
 478
 479         fn zero_value_invoice(payment_preimage: PaymentPreimage) -> Invoice {
 480                 let payment_hash = Sha256::hash(&payment_preimage.0);
 481                 let private_key = SecretKey::from_slice(&[42; 32]).unwrap();
 482                 InvoiceBuilder::new(Currency::Bitcoin)
 483                         .description("test".into())
 484                         .payment_hash(payment_hash)
 485                         .payment_secret(PaymentSecret([0; 32]))
 486                         .current_timestamp()
 487                         .min_final_cltv_expiry(144)
 488                         .build_signed(|hash| {
 489                                 Secp256k1::new().sign_recoverable(hash, &private_key)
 490                         })
 491                         .unwrap()
 492         }
 493
 494         fn expired_invoice(payment_preimage: PaymentPreimage) -> Invoice {
 495                 let payment_hash = Sha256::hash(&payment_preimage.0);
 496                 let private_key = SecretKey::from_slice(&[42; 32]).unwrap();
 497                 let timestamp = SystemTime::now()
 498                         .checked_sub(Duration::from_secs(DEFAULT_EXPIRY_TIME * 2))
 499                         .unwrap();
 500                 InvoiceBuilder::new(Currency::Bitcoin)
 501                         .description("test".into())
 502                         .payment_hash(payment_hash)
 503                         .payment_secret(PaymentSecret([0; 32]))
 504                         .timestamp(timestamp)
 505                         .min_final_cltv_expiry(144)
 506                         .amount_milli_satoshis(128)
 507                         .build_signed(|hash| {
 508                                 Secp256k1::new().sign_recoverable(hash, &private_key)
 509                         })
 510                         .unwrap()
 511         }
 512
 513         #[test]
 514         fn pays_invoice_on_first_attempt() {
 515                 let event_handled = core::cell::RefCell::new(false);
 516                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 517
 518                 let payment_preimage = PaymentPreimage([1; 32]);
 519                 let invoice = invoice(payment_preimage);
 520                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 521
 522                 let payer = TestPayer::new();
 523                 let router = TestRouter {};
 524                 let scorer = RefCell::new(TestScorer::new());
 525                 let logger = TestLogger::new();
 526                 let invoice_payer =
 527                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(0));
 528
 529                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 530                 assert_eq!(*payer.attempts.borrow(), 1);
 531
 532                 invoice_payer.handle_event(&Event::PaymentSent {
 533                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
 534                 });
 535                 assert_eq!(*event_handled.borrow(), true);
 536                 assert_eq!(*payer.attempts.borrow(), 1);
 537         }
 538
 539         #[test]
 540         fn pays_invoice_on_retry() {
 541                 let event_handled = core::cell::RefCell::new(false);
 542                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 543
 544                 let payment_preimage = PaymentPreimage([1; 32]);
 545                 let invoice = invoice(payment_preimage);
 546                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 547                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 548
 549                 let payer = TestPayer::new()
 550                         .expect_value_msat(final_value_msat)
 551                         .expect_value_msat(final_value_msat / 2);
 552                 let router = TestRouter {};
 553                 let scorer = RefCell::new(TestScorer::new());
 554                 let logger = TestLogger::new();
 555                 let invoice_payer =
 556                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 557
 558                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 559                 assert_eq!(*payer.attempts.borrow(), 1);
 560
 561                 let event = Event::PaymentPathFailed {
 562                         payment_id,
 563                         payment_hash,
 564                         network_update: None,
 565                         rejected_by_dest: false,
 566                         all_paths_failed: false,
 567                         path: TestRouter::path_for_value(final_value_msat),
 568                         short_channel_id: None,
 569                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 570                 };
 571                 invoice_payer.handle_event(&event);
 572                 assert_eq!(*event_handled.borrow(), false);
 573                 assert_eq!(*payer.attempts.borrow(), 2);
 574
 575                 invoice_payer.handle_event(&Event::PaymentSent {
 576                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
 577                 });
 578                 assert_eq!(*event_handled.borrow(), true);
 579                 assert_eq!(*payer.attempts.borrow(), 2);
 580         }
 581
 582         #[test]
 583         fn retries_payment_path_for_unknown_payment() {
 584                 let event_handled = core::cell::RefCell::new(false);
 585                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 586
 587                 let payment_preimage = PaymentPreimage([1; 32]);
 588                 let invoice = invoice(payment_preimage);
 589                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 590                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 591
 592                 let payer = TestPayer::new();
 593                 let router = TestRouter {};
 594                 let scorer = RefCell::new(TestScorer::new());
 595                 let logger = TestLogger::new();
 596                 let invoice_payer =
 597                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 598
 599                 let payment_id = Some(PaymentId([1; 32]));
 600                 let event = Event::PaymentPathFailed {
 601                         payment_id,
 602                         payment_hash,
 603                         network_update: None,
 604                         rejected_by_dest: false,
 605                         all_paths_failed: false,
 606                         path: TestRouter::path_for_value(final_value_msat),
 607                         short_channel_id: None,
 608                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 609                 };
 610                 invoice_payer.handle_event(&event);
 611                 assert_eq!(*event_handled.borrow(), false);
 612                 assert_eq!(*payer.attempts.borrow(), 1);
 613
 614                 invoice_payer.handle_event(&event);
 615                 assert_eq!(*event_handled.borrow(), false);
 616                 assert_eq!(*payer.attempts.borrow(), 2);
 617
 618                 invoice_payer.handle_event(&Event::PaymentSent {
 619                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
 620                 });
 621                 assert_eq!(*event_handled.borrow(), true);
 622                 assert_eq!(*payer.attempts.borrow(), 2);
 623         }
 624
 625         #[test]
 626         fn fails_paying_invoice_after_max_retries() {
 627                 let event_handled = core::cell::RefCell::new(false);
 628                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 629
 630                 let payment_preimage = PaymentPreimage([1; 32]);
 631                 let invoice = invoice(payment_preimage);
 632                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 633
 634                 let payer = TestPayer::new()
 635                         .expect_value_msat(final_value_msat)
 636                         .expect_value_msat(final_value_msat / 2)
 637                         .expect_value_msat(final_value_msat / 2);
 638                 let router = TestRouter {};
 639                 let scorer = RefCell::new(TestScorer::new());
 640                 let logger = TestLogger::new();
 641                 let invoice_payer =
 642                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 643
 644                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 645                 assert_eq!(*payer.attempts.borrow(), 1);
 646
 647                 let event = Event::PaymentPathFailed {
 648                         payment_id,
 649                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 650                         network_update: None,
 651                         rejected_by_dest: false,
 652                         all_paths_failed: true,
 653                         path: TestRouter::path_for_value(final_value_msat),
 654                         short_channel_id: None,
 655                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 656                 };
 657                 invoice_payer.handle_event(&event);
 658                 assert_eq!(*event_handled.borrow(), false);
 659                 assert_eq!(*payer.attempts.borrow(), 2);
 660
 661                 let event = Event::PaymentPathFailed {
 662                         payment_id,
 663                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 664                         network_update: None,
 665                         rejected_by_dest: false,
 666                         all_paths_failed: false,
 667                         path: TestRouter::path_for_value(final_value_msat / 2),
 668                         short_channel_id: None,
 669                         retry: Some(RouteParameters {
 670                                 final_value_msat: final_value_msat / 2, ..TestRouter::retry_for_invoice(&invoice)
 671                         }),
 672                 };
 673                 invoice_payer.handle_event(&event);
 674                 assert_eq!(*event_handled.borrow(), false);
 675                 assert_eq!(*payer.attempts.borrow(), 3);
 676
 677                 invoice_payer.handle_event(&event);
 678                 assert_eq!(*event_handled.borrow(), true);
 679                 assert_eq!(*payer.attempts.borrow(), 3);
 680         }
 681
 682         #[test]
 683         fn fails_paying_invoice_with_missing_retry_params() {
 684                 let event_handled = core::cell::RefCell::new(false);
 685                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 686
 687                 let payer = TestPayer::new();
 688                 let router = TestRouter {};
 689                 let scorer = RefCell::new(TestScorer::new());
 690                 let logger = TestLogger::new();
 691                 let invoice_payer =
 692                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 693
 694                 let payment_preimage = PaymentPreimage([1; 32]);
 695                 let invoice = invoice(payment_preimage);
 696                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 697                 assert_eq!(*payer.attempts.borrow(), 1);
 698
 699                 let event = Event::PaymentPathFailed {
 700                         payment_id,
 701                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 702                         network_update: None,
 703                         rejected_by_dest: false,
 704                         all_paths_failed: false,
 705                         path: vec![],
 706                         short_channel_id: None,
 707                         retry: None,
 708                 };
 709                 invoice_payer.handle_event(&event);
 710                 assert_eq!(*event_handled.borrow(), true);
 711                 assert_eq!(*payer.attempts.borrow(), 1);
 712         }
 713
 714         #[test]
 715         fn fails_paying_invoice_after_expiration() {
 716                 let event_handled = core::cell::RefCell::new(false);
 717                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 718
 719                 let payer = TestPayer::new();
 720                 let router = TestRouter {};
 721                 let scorer = RefCell::new(TestScorer::new());
 722                 let logger = TestLogger::new();
 723                 let invoice_payer =
 724                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 725
 726                 let payment_preimage = PaymentPreimage([1; 32]);
 727                 let invoice = expired_invoice(payment_preimage);
 728                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 729                 assert_eq!(*payer.attempts.borrow(), 1);
 730
 731                 let event = Event::PaymentPathFailed {
 732                         payment_id,
 733                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 734                         network_update: None,
 735                         rejected_by_dest: false,
 736                         all_paths_failed: false,
 737                         path: vec![],
 738                         short_channel_id: None,
 739                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 740                 };
 741                 invoice_payer.handle_event(&event);
 742                 assert_eq!(*event_handled.borrow(), true);
 743                 assert_eq!(*payer.attempts.borrow(), 1);
 744         }
 745
 746         #[test]
 747         fn fails_paying_invoice_after_retry_error() {
 748                 let event_handled = core::cell::RefCell::new(false);
 749                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 750
 751                 let payment_preimage = PaymentPreimage([1; 32]);
 752                 let invoice = invoice(payment_preimage);
 753                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 754
 755                 let payer = TestPayer::new()
 756                         .fails_on_attempt(2)
 757                         .expect_value_msat(final_value_msat);
 758                 let router = TestRouter {};
 759                 let scorer = RefCell::new(TestScorer::new());
 760                 let logger = TestLogger::new();
 761                 let invoice_payer =
 762                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 763
 764                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 765                 assert_eq!(*payer.attempts.borrow(), 1);
 766
 767                 let event = Event::PaymentPathFailed {
 768                         payment_id,
 769                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 770                         network_update: None,
 771                         rejected_by_dest: false,
 772                         all_paths_failed: false,
 773                         path: TestRouter::path_for_value(final_value_msat / 2),
 774                         short_channel_id: None,
 775                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 776                 };
 777                 invoice_payer.handle_event(&event);
 778                 assert_eq!(*event_handled.borrow(), true);
 779                 assert_eq!(*payer.attempts.borrow(), 2);
 780         }
 781
 782         #[test]
 783         fn fails_paying_invoice_after_rejected_by_payee() {
 784                 let event_handled = core::cell::RefCell::new(false);
 785                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 786
 787                 let payer = TestPayer::new();
 788                 let router = TestRouter {};
 789                 let scorer = RefCell::new(TestScorer::new());
 790                 let logger = TestLogger::new();
 791                 let invoice_payer =
 792                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 793
 794                 let payment_preimage = PaymentPreimage([1; 32]);
 795                 let invoice = invoice(payment_preimage);
 796                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 797                 assert_eq!(*payer.attempts.borrow(), 1);
 798
 799                 let event = Event::PaymentPathFailed {
 800                         payment_id,
 801                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 802                         network_update: None,
 803                         rejected_by_dest: true,
 804                         all_paths_failed: false,
 805                         path: vec![],
 806                         short_channel_id: None,
 807                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 808                 };
 809                 invoice_payer.handle_event(&event);
 810                 assert_eq!(*event_handled.borrow(), true);
 811                 assert_eq!(*payer.attempts.borrow(), 1);
 812         }
 813
 814         #[test]
 815         fn fails_repaying_invoice_with_pending_payment() {
 816                 let event_handled = core::cell::RefCell::new(false);
 817                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 818
 819                 let payer = TestPayer::new();
 820                 let router = TestRouter {};
 821                 let scorer = RefCell::new(TestScorer::new());
 822                 let logger = TestLogger::new();
 823                 let invoice_payer =
 824                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(0));
 825
 826                 let payment_preimage = PaymentPreimage([1; 32]);
 827                 let invoice = invoice(payment_preimage);
 828                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 829
 830                 // Cannot repay an invoice pending payment.
 831                 match invoice_payer.pay_invoice(&invoice) {
 832                         Err(PaymentError::Invoice("payment pending")) => {},
 833                         Err(_) => panic!("unexpected error"),
 834                         Ok(_) => panic!("expected invoice error"),
 835                 }
 836
 837                 // Can repay an invoice once cleared from cache.
 838                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 839                 invoice_payer.remove_cached_payment(&payment_hash);
 840                 assert!(invoice_payer.pay_invoice(&invoice).is_ok());
 841
 842                 // Cannot retry paying an invoice if cleared from cache.
 843                 invoice_payer.remove_cached_payment(&payment_hash);
 844                 let event = Event::PaymentPathFailed {
 845                         payment_id,
 846                         payment_hash,
 847                         network_update: None,
 848                         rejected_by_dest: false,
 849                         all_paths_failed: false,
 850                         path: vec![],
 851                         short_channel_id: None,
 852                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 853                 };
 854                 invoice_payer.handle_event(&event);
 855                 assert_eq!(*event_handled.borrow(), true);
 856         }
 857
 858         #[test]
 859         fn fails_paying_invoice_with_routing_errors() {
 860                 let payer = TestPayer::new();
 861                 let router = FailingRouter {};
 862                 let scorer = RefCell::new(TestScorer::new());
 863                 let logger = TestLogger::new();
 864                 let invoice_payer =
 865                         InvoicePayer::new(&payer, router, &scorer, &logger, |_: &_| {}, RetryAttempts(0));
 866
 867                 let payment_preimage = PaymentPreimage([1; 32]);
 868                 let invoice = invoice(payment_preimage);
 869                 match invoice_payer.pay_invoice(&invoice) {
 870                         Err(PaymentError::Routing(_)) => {},
 871                         Err(_) => panic!("unexpected error"),
 872                         Ok(_) => panic!("expected routing error"),
 873                 }
 874         }
 875
 876         #[test]
 877         fn fails_paying_invoice_with_sending_errors() {
 878                 let payer = TestPayer::new().fails_on_attempt(1);
 879                 let router = TestRouter {};
 880                 let scorer = RefCell::new(TestScorer::new());
 881                 let logger = TestLogger::new();
 882                 let invoice_payer =
 883                         InvoicePayer::new(&payer, router, &scorer, &logger, |_: &_| {}, RetryAttempts(0));
 884
 885                 let payment_preimage = PaymentPreimage([1; 32]);
 886                 let invoice = invoice(payment_preimage);
 887                 match invoice_payer.pay_invoice(&invoice) {
 888                         Err(PaymentError::Sending(_)) => {},
 889                         Err(_) => panic!("unexpected error"),
 890                         Ok(_) => panic!("expected sending error"),
 891                 }
 892         }
 893
 894         #[test]
 895         fn pays_zero_value_invoice_using_amount() {
 896                 let event_handled = core::cell::RefCell::new(false);
 897                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 898
 899                 let payment_preimage = PaymentPreimage([1; 32]);
 900                 let invoice = zero_value_invoice(payment_preimage);
 901                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 902                 let final_value_msat = 100;
 903
 904                 let payer = TestPayer::new().expect_value_msat(final_value_msat);
 905                 let router = TestRouter {};
 906                 let scorer = RefCell::new(TestScorer::new());
 907                 let logger = TestLogger::new();
 908                 let invoice_payer =
 909                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(0));
 910
 911                 let payment_id =
 912                         Some(invoice_payer.pay_zero_value_invoice(&invoice, final_value_msat).unwrap());
 913                 assert_eq!(*payer.attempts.borrow(), 1);
 914
 915                 invoice_payer.handle_event(&Event::PaymentSent {
 916                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
 917                 });
 918                 assert_eq!(*event_handled.borrow(), true);
 919                 assert_eq!(*payer.attempts.borrow(), 1);
 920         }
 921
 922         #[test]
 923         fn fails_paying_zero_value_invoice_with_amount() {
 924                 let event_handled = core::cell::RefCell::new(false);
 925                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 926
 927                 let payer = TestPayer::new();
 928                 let router = TestRouter {};
 929                 let scorer = RefCell::new(TestScorer::new());
 930                 let logger = TestLogger::new();
 931                 let invoice_payer =
 932                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(0));
 933
 934                 let payment_preimage = PaymentPreimage([1; 32]);
 935                 let invoice = invoice(payment_preimage);
 936
 937                 // Cannot repay an invoice pending payment.
 938                 match invoice_payer.pay_zero_value_invoice(&invoice, 100) {
 939                         Err(PaymentError::Invoice("amount unexpected")) => {},
 940                         Err(_) => panic!("unexpected error"),
 941                         Ok(_) => panic!("expected invoice error"),
 942                 }
 943         }
 944
 945         #[test]
 946         fn scores_failed_channel() {
 947                 let event_handled = core::cell::RefCell::new(false);
 948                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 949
 950                 let payment_preimage = PaymentPreimage([1; 32]);
 951                 let invoice = invoice(payment_preimage);
 952                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 953                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 954                 let path = TestRouter::path_for_value(final_value_msat);
 955                 let short_channel_id = Some(path[0].short_channel_id);
 956
 957                 // Expect that scorer is given short_channel_id upon handling the event.
 958                 let payer = TestPayer::new();
 959                 let router = TestRouter {};
 960                 let scorer = RefCell::new(TestScorer::new().expect_channel_failure(short_channel_id.unwrap()));
 961                 let logger = TestLogger::new();
 962                 let invoice_payer =
 963                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 964
 965                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 966                 let event = Event::PaymentPathFailed {
 967                         payment_id,
 968                         payment_hash,
 969                         network_update: None,
 970                         rejected_by_dest: false,
 971                         all_paths_failed: false,
 972                         path,
 973                         short_channel_id,
 974                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 975                 };
 976                 invoice_payer.handle_event(&event);
 977         }
 978
 979         struct TestRouter;
 980
 981         impl TestRouter {
 982                 fn route_for_value(final_value_msat: u64) -> Route {
 983                         Route {
 984                                 paths: vec![
 985                                         vec![RouteHop {
 986                                                 pubkey: PublicKey::from_slice(&hex::decode("02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619").unwrap()[..]).unwrap(),
 987                                                 channel_features: ChannelFeatures::empty(),
 988                                                 node_features: NodeFeatures::empty(),
 989                                                 short_channel_id: 0, fee_msat: final_value_msat / 2, cltv_expiry_delta: 144
 990                                         }],
 991                                         vec![RouteHop {
 992                                                 pubkey: PublicKey::from_slice(&hex::decode("0324653eac434488002cc06bbfb7f10fe18991e35f9fe4302dbea6d2353dc0ab1c").unwrap()[..]).unwrap(),
 993                                                 channel_features: ChannelFeatures::empty(),
 994                                                 node_features: NodeFeatures::empty(),
 995                                                 short_channel_id: 1, fee_msat: final_value_msat / 2, cltv_expiry_delta: 144
 996                                         }],
 997                                 ],
 998                                 payee: None,
 999                         }
1000                 }
1001
1002                 fn path_for_value(final_value_msat: u64) -> Vec<RouteHop> {
1003                         TestRouter::route_for_value(final_value_msat).paths[0].clone()
1004                 }
1005
1006                 fn retry_for_invoice(invoice: &Invoice) -> RouteParameters {
1007                         let mut payee = Payee::new(invoice.recover_payee_pub_key())
1008                                 .with_expiry_time(expiry_time_from_unix_epoch(invoice).as_secs())
1009                                 .with_route_hints(invoice.route_hints());
1010                         if let Some(features) = invoice.features() {
1011                                 payee = payee.with_features(features.clone());
1012                         }
1013                         let final_value_msat = invoice.amount_milli_satoshis().unwrap() / 2;
1014                         RouteParameters {
1015                                 payee,
1016                                 final_value_msat,
1017                                 final_cltv_expiry_delta: invoice.min_final_cltv_expiry() as u32,
1018                         }
1019                 }
1020         }
1021
1022         impl<S: routing::Score> Router<S> for TestRouter {
1023                 fn find_route(
1024                         &self,
1025                         _payer: &PublicKey,
1026                         params: &RouteParameters,
1027                         _first_hops: Option<&[&ChannelDetails]>,
1028                         _scorer: &S,
1029                 ) -> Result<Route, LightningError> {
1030                         Ok(Route {
1031                                 payee: Some(params.payee.clone()), ..Self::route_for_value(params.final_value_msat)
1032                         })
1033                 }
1034         }
1035
1036         struct FailingRouter;
1037
1038         impl<S: routing::Score> Router<S> for FailingRouter {
1039                 fn find_route(
1040                         &self,
1041                         _payer: &PublicKey,
1042                         _params: &RouteParameters,
1043                         _first_hops: Option<&[&ChannelDetails]>,
1044                         _scorer: &S,
1045                 ) -> Result<Route, LightningError> {
1046                         Err(LightningError { err: String::new(), action: ErrorAction::IgnoreError })
1047                 }
1048         }
1049
1050         struct TestScorer {
1051                 expectations: std::collections::VecDeque<u64>,
1052         }
1053
1054         impl TestScorer {
1055                 fn new() -> Self {
1056                         Self {
1057                                 expectations: std::collections::VecDeque::new(),
1058                         }
1059                 }
1060
1061                 fn expect_channel_failure(mut self, short_channel_id: u64) -> Self {
1062                         self.expectations.push_back(short_channel_id);
1063                         self
1064                 }
1065         }
1066
1067         impl routing::Score for TestScorer {
1068                 fn channel_penalty_msat(
1069                         &self, _short_channel_id: u64, _source: &NodeId, _target: &NodeId
1070                 ) -> u64 { 0 }
1071
1072                 fn payment_path_failed(&mut self, _path: &Vec<RouteHop>, short_channel_id: u64) {
1073                         if let Some(expected_short_channel_id) = self.expectations.pop_front() {
1074                                 assert_eq!(short_channel_id, expected_short_channel_id);
1075                         }
1076                 }
1077         }
1078
1079         impl Drop for TestScorer {
1080                 fn drop(&mut self) {
1081                         if std::thread::panicking() {
1082                                 return;
1083                         }
1084
1085                         if !self.expectations.is_empty() {
1086                                 panic!("Unsatisfied channel failure expectations: {:?}", self.expectations);
1087                         }
1088                 }
1089         }
1090
1091         struct TestPayer {
1092                 expectations: core::cell::RefCell<std::collections::VecDeque<u64>>,
1093                 attempts: core::cell::RefCell<usize>,
1094                 failing_on_attempt: Option<usize>,
1095         }
1096
1097         impl TestPayer {
1098                 fn new() -> Self {
1099                         Self {
1100                                 expectations: core::cell::RefCell::new(std::collections::VecDeque::new()),
1101                                 attempts: core::cell::RefCell::new(0),
1102                                 failing_on_attempt: None,
1103                         }
1104                 }
1105
1106                 fn expect_value_msat(self, value_msat: u64) -> Self {
1107                         self.expectations.borrow_mut().push_back(value_msat);
1108                         self
1109                 }
1110
1111                 fn fails_on_attempt(self, attempt: usize) -> Self {
1112                         Self {
1113                                 expectations: core::cell::RefCell::new(self.expectations.borrow().clone()),
1114                                 attempts: core::cell::RefCell::new(0),
1115                                 failing_on_attempt: Some(attempt),
1116                         }
1117                 }
1118
1119                 fn check_attempts(&self) -> bool {
1120                         let mut attempts = self.attempts.borrow_mut();
1121                         *attempts += 1;
1122                         match self.failing_on_attempt {
1123                                 None => true,
1124                                 Some(attempt) if attempt != *attempts => true,
1125                                 Some(_) => false,
1126                         }
1127                 }
1128
1129                 fn check_value_msats(&self, route: &Route) {
1130                         let expected_value_msats = self.expectations.borrow_mut().pop_front();
1131                         if let Some(expected_value_msats) = expected_value_msats {
1132                                 let actual_value_msats = route.get_total_amount();
1133                                 assert_eq!(actual_value_msats, expected_value_msats);
1134                         }
1135                 }
1136         }
1137
1138         impl Drop for TestPayer {
1139                 fn drop(&mut self) {
1140                         if std::thread::panicking() {
1141                                 return;
1142                         }
1143
1144                         if !self.expectations.borrow().is_empty() {
1145                                 panic!("Unsatisfied payment expectations: {:?}", self.expectations.borrow());
1146                         }
1147                 }
1148         }
1149
1150         impl Payer for TestPayer {
1151                 fn node_id(&self) -> PublicKey {
1152                         let secp_ctx = Secp256k1::new();
1153                         PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap())
1154                 }
1155
1156                 fn first_hops(&self) -> Vec<ChannelDetails> {
1157                         Vec::new()
1158                 }
1159
1160                 fn send_payment(
1161                         &self,
1162                         route: &Route,
1163                         _payment_hash: PaymentHash,
1164                         _payment_secret: &Option<PaymentSecret>
1165                 ) -> Result<PaymentId, PaymentSendFailure> {
1166                         if self.check_attempts() {
1167                                 self.check_value_msats(route);
1168                                 Ok(PaymentId([1; 32]))
1169                         } else {
1170                                 Err(PaymentSendFailure::ParameterError(APIError::MonitorUpdateFailed))
1171                         }
1172                 }
1173
1174                 fn retry_payment(
1175                         &self, route: &Route, _payment_id: PaymentId
1176                 ) -> Result<(), PaymentSendFailure> {
1177                         if self.check_attempts() {
1178                                 self.check_value_msats(route);
1179                                 Ok(())
1180                         } else {
1181                                 Err(PaymentSendFailure::ParameterError(APIError::MonitorUpdateFailed))
1182                         }
1183                 }
1184         }
1185 }