_ 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 utils::create_invoice_from_channelmanager;
 451         use bitcoin_hashes::sha256::Hash as Sha256;
 452         use lightning::ln::PaymentPreimage;
 453         use lightning::ln::features::{ChannelFeatures, NodeFeatures, InitFeatures};
 454         use lightning::ln::functional_test_utils::*;
 455         use lightning::ln::msgs::{ErrorAction, LightningError};
 456         use lightning::routing::network_graph::NodeId;
 457         use lightning::routing::router::{Payee, Route, RouteHop};
 458         use lightning::util::test_utils::TestLogger;
 459         use lightning::util::errors::APIError;
 460         use lightning::util::events::{Event, MessageSendEventsProvider};
 461         use secp256k1::{SecretKey, PublicKey, Secp256k1};
 462         use std::cell::RefCell;
 463         use std::collections::VecDeque;
 464         use std::time::{SystemTime, Duration};
 465
 466         fn invoice(payment_preimage: PaymentPreimage) -> Invoice {
 467                 let payment_hash = Sha256::hash(&payment_preimage.0);
 468                 let private_key = SecretKey::from_slice(&[42; 32]).unwrap();
 469                 InvoiceBuilder::new(Currency::Bitcoin)
 470                         .description("test".into())
 471                         .payment_hash(payment_hash)
 472                         .payment_secret(PaymentSecret([0; 32]))
 473                         .current_timestamp()
 474                         .min_final_cltv_expiry(144)
 475                         .amount_milli_satoshis(128)
 476                         .build_signed(|hash| {
 477                                 Secp256k1::new().sign_recoverable(hash, &private_key)
 478                         })
 479                         .unwrap()
 480         }
 481
 482         fn zero_value_invoice(payment_preimage: PaymentPreimage) -> Invoice {
 483                 let payment_hash = Sha256::hash(&payment_preimage.0);
 484                 let private_key = SecretKey::from_slice(&[42; 32]).unwrap();
 485                 InvoiceBuilder::new(Currency::Bitcoin)
 486                         .description("test".into())
 487                         .payment_hash(payment_hash)
 488                         .payment_secret(PaymentSecret([0; 32]))
 489                         .current_timestamp()
 490                         .min_final_cltv_expiry(144)
 491                         .build_signed(|hash| {
 492                                 Secp256k1::new().sign_recoverable(hash, &private_key)
 493                         })
 494                         .unwrap()
 495         }
 496
 497         fn expired_invoice(payment_preimage: PaymentPreimage) -> Invoice {
 498                 let payment_hash = Sha256::hash(&payment_preimage.0);
 499                 let private_key = SecretKey::from_slice(&[42; 32]).unwrap();
 500                 let timestamp = SystemTime::now()
 501                         .checked_sub(Duration::from_secs(DEFAULT_EXPIRY_TIME * 2))
 502                         .unwrap();
 503                 InvoiceBuilder::new(Currency::Bitcoin)
 504                         .description("test".into())
 505                         .payment_hash(payment_hash)
 506                         .payment_secret(PaymentSecret([0; 32]))
 507                         .timestamp(timestamp)
 508                         .min_final_cltv_expiry(144)
 509                         .amount_milli_satoshis(128)
 510                         .build_signed(|hash| {
 511                                 Secp256k1::new().sign_recoverable(hash, &private_key)
 512                         })
 513                         .unwrap()
 514         }
 515
 516         #[test]
 517         fn pays_invoice_on_first_attempt() {
 518                 let event_handled = core::cell::RefCell::new(false);
 519                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 520
 521                 let payment_preimage = PaymentPreimage([1; 32]);
 522                 let invoice = invoice(payment_preimage);
 523                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 524
 525                 let payer = TestPayer::new();
 526                 let router = TestRouter {};
 527                 let scorer = RefCell::new(TestScorer::new());
 528                 let logger = TestLogger::new();
 529                 let invoice_payer =
 530                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(0));
 531
 532                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 533                 assert_eq!(*payer.attempts.borrow(), 1);
 534
 535                 invoice_payer.handle_event(&Event::PaymentSent {
 536                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
 537                 });
 538                 assert_eq!(*event_handled.borrow(), true);
 539                 assert_eq!(*payer.attempts.borrow(), 1);
 540         }
 541
 542         #[test]
 543         fn pays_invoice_on_retry() {
 544                 let event_handled = core::cell::RefCell::new(false);
 545                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 546
 547                 let payment_preimage = PaymentPreimage([1; 32]);
 548                 let invoice = invoice(payment_preimage);
 549                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 550                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 551
 552                 let payer = TestPayer::new()
 553                         .expect_value_msat(final_value_msat)
 554                         .expect_value_msat(final_value_msat / 2);
 555                 let router = TestRouter {};
 556                 let scorer = RefCell::new(TestScorer::new());
 557                 let logger = TestLogger::new();
 558                 let invoice_payer =
 559                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 560
 561                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 562                 assert_eq!(*payer.attempts.borrow(), 1);
 563
 564                 let event = Event::PaymentPathFailed {
 565                         payment_id,
 566                         payment_hash,
 567                         network_update: None,
 568                         rejected_by_dest: false,
 569                         all_paths_failed: false,
 570                         path: TestRouter::path_for_value(final_value_msat),
 571                         short_channel_id: None,
 572                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 573                 };
 574                 invoice_payer.handle_event(&event);
 575                 assert_eq!(*event_handled.borrow(), false);
 576                 assert_eq!(*payer.attempts.borrow(), 2);
 577
 578                 invoice_payer.handle_event(&Event::PaymentSent {
 579                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
 580                 });
 581                 assert_eq!(*event_handled.borrow(), true);
 582                 assert_eq!(*payer.attempts.borrow(), 2);
 583         }
 584
 585         #[test]
 586         fn retries_payment_path_for_unknown_payment() {
 587                 let event_handled = core::cell::RefCell::new(false);
 588                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 589
 590                 let payment_preimage = PaymentPreimage([1; 32]);
 591                 let invoice = invoice(payment_preimage);
 592                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 593                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 594
 595                 let payer = TestPayer::new();
 596                 let router = TestRouter {};
 597                 let scorer = RefCell::new(TestScorer::new());
 598                 let logger = TestLogger::new();
 599                 let invoice_payer =
 600                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 601
 602                 let payment_id = Some(PaymentId([1; 32]));
 603                 let event = Event::PaymentPathFailed {
 604                         payment_id,
 605                         payment_hash,
 606                         network_update: None,
 607                         rejected_by_dest: false,
 608                         all_paths_failed: false,
 609                         path: TestRouter::path_for_value(final_value_msat),
 610                         short_channel_id: None,
 611                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 612                 };
 613                 invoice_payer.handle_event(&event);
 614                 assert_eq!(*event_handled.borrow(), false);
 615                 assert_eq!(*payer.attempts.borrow(), 1);
 616
 617                 invoice_payer.handle_event(&event);
 618                 assert_eq!(*event_handled.borrow(), false);
 619                 assert_eq!(*payer.attempts.borrow(), 2);
 620
 621                 invoice_payer.handle_event(&Event::PaymentSent {
 622                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
 623                 });
 624                 assert_eq!(*event_handled.borrow(), true);
 625                 assert_eq!(*payer.attempts.borrow(), 2);
 626         }
 627
 628         #[test]
 629         fn fails_paying_invoice_after_max_retries() {
 630                 let event_handled = core::cell::RefCell::new(false);
 631                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 632
 633                 let payment_preimage = PaymentPreimage([1; 32]);
 634                 let invoice = invoice(payment_preimage);
 635                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 636
 637                 let payer = TestPayer::new()
 638                         .expect_value_msat(final_value_msat)
 639                         .expect_value_msat(final_value_msat / 2)
 640                         .expect_value_msat(final_value_msat / 2);
 641                 let router = TestRouter {};
 642                 let scorer = RefCell::new(TestScorer::new());
 643                 let logger = TestLogger::new();
 644                 let invoice_payer =
 645                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 646
 647                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 648                 assert_eq!(*payer.attempts.borrow(), 1);
 649
 650                 let event = Event::PaymentPathFailed {
 651                         payment_id,
 652                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 653                         network_update: None,
 654                         rejected_by_dest: false,
 655                         all_paths_failed: true,
 656                         path: TestRouter::path_for_value(final_value_msat),
 657                         short_channel_id: None,
 658                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 659                 };
 660                 invoice_payer.handle_event(&event);
 661                 assert_eq!(*event_handled.borrow(), false);
 662                 assert_eq!(*payer.attempts.borrow(), 2);
 663
 664                 let event = Event::PaymentPathFailed {
 665                         payment_id,
 666                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 667                         network_update: None,
 668                         rejected_by_dest: false,
 669                         all_paths_failed: false,
 670                         path: TestRouter::path_for_value(final_value_msat / 2),
 671                         short_channel_id: None,
 672                         retry: Some(RouteParameters {
 673                                 final_value_msat: final_value_msat / 2, ..TestRouter::retry_for_invoice(&invoice)
 674                         }),
 675                 };
 676                 invoice_payer.handle_event(&event);
 677                 assert_eq!(*event_handled.borrow(), false);
 678                 assert_eq!(*payer.attempts.borrow(), 3);
 679
 680                 invoice_payer.handle_event(&event);
 681                 assert_eq!(*event_handled.borrow(), true);
 682                 assert_eq!(*payer.attempts.borrow(), 3);
 683         }
 684
 685         #[test]
 686         fn fails_paying_invoice_with_missing_retry_params() {
 687                 let event_handled = core::cell::RefCell::new(false);
 688                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 689
 690                 let payer = TestPayer::new();
 691                 let router = TestRouter {};
 692                 let scorer = RefCell::new(TestScorer::new());
 693                 let logger = TestLogger::new();
 694                 let invoice_payer =
 695                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 696
 697                 let payment_preimage = PaymentPreimage([1; 32]);
 698                 let invoice = invoice(payment_preimage);
 699                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 700                 assert_eq!(*payer.attempts.borrow(), 1);
 701
 702                 let event = Event::PaymentPathFailed {
 703                         payment_id,
 704                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 705                         network_update: None,
 706                         rejected_by_dest: false,
 707                         all_paths_failed: false,
 708                         path: vec![],
 709                         short_channel_id: None,
 710                         retry: None,
 711                 };
 712                 invoice_payer.handle_event(&event);
 713                 assert_eq!(*event_handled.borrow(), true);
 714                 assert_eq!(*payer.attempts.borrow(), 1);
 715         }
 716
 717         #[test]
 718         fn fails_paying_invoice_after_expiration() {
 719                 let event_handled = core::cell::RefCell::new(false);
 720                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 721
 722                 let payer = TestPayer::new();
 723                 let router = TestRouter {};
 724                 let scorer = RefCell::new(TestScorer::new());
 725                 let logger = TestLogger::new();
 726                 let invoice_payer =
 727                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 728
 729                 let payment_preimage = PaymentPreimage([1; 32]);
 730                 let invoice = expired_invoice(payment_preimage);
 731                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 732                 assert_eq!(*payer.attempts.borrow(), 1);
 733
 734                 let event = Event::PaymentPathFailed {
 735                         payment_id,
 736                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 737                         network_update: None,
 738                         rejected_by_dest: false,
 739                         all_paths_failed: false,
 740                         path: vec![],
 741                         short_channel_id: None,
 742                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 743                 };
 744                 invoice_payer.handle_event(&event);
 745                 assert_eq!(*event_handled.borrow(), true);
 746                 assert_eq!(*payer.attempts.borrow(), 1);
 747         }
 748
 749         #[test]
 750         fn fails_paying_invoice_after_retry_error() {
 751                 let event_handled = core::cell::RefCell::new(false);
 752                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 753
 754                 let payment_preimage = PaymentPreimage([1; 32]);
 755                 let invoice = invoice(payment_preimage);
 756                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 757
 758                 let payer = TestPayer::new()
 759                         .fails_on_attempt(2)
 760                         .expect_value_msat(final_value_msat);
 761                 let router = TestRouter {};
 762                 let scorer = RefCell::new(TestScorer::new());
 763                 let logger = TestLogger::new();
 764                 let invoice_payer =
 765                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 766
 767                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 768                 assert_eq!(*payer.attempts.borrow(), 1);
 769
 770                 let event = Event::PaymentPathFailed {
 771                         payment_id,
 772                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 773                         network_update: None,
 774                         rejected_by_dest: false,
 775                         all_paths_failed: false,
 776                         path: TestRouter::path_for_value(final_value_msat / 2),
 777                         short_channel_id: None,
 778                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 779                 };
 780                 invoice_payer.handle_event(&event);
 781                 assert_eq!(*event_handled.borrow(), true);
 782                 assert_eq!(*payer.attempts.borrow(), 2);
 783         }
 784
 785         #[test]
 786         fn fails_paying_invoice_after_rejected_by_payee() {
 787                 let event_handled = core::cell::RefCell::new(false);
 788                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 789
 790                 let payer = TestPayer::new();
 791                 let router = TestRouter {};
 792                 let scorer = RefCell::new(TestScorer::new());
 793                 let logger = TestLogger::new();
 794                 let invoice_payer =
 795                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 796
 797                 let payment_preimage = PaymentPreimage([1; 32]);
 798                 let invoice = invoice(payment_preimage);
 799                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 800                 assert_eq!(*payer.attempts.borrow(), 1);
 801
 802                 let event = Event::PaymentPathFailed {
 803                         payment_id,
 804                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 805                         network_update: None,
 806                         rejected_by_dest: true,
 807                         all_paths_failed: false,
 808                         path: vec![],
 809                         short_channel_id: None,
 810                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 811                 };
 812                 invoice_payer.handle_event(&event);
 813                 assert_eq!(*event_handled.borrow(), true);
 814                 assert_eq!(*payer.attempts.borrow(), 1);
 815         }
 816
 817         #[test]
 818         fn fails_repaying_invoice_with_pending_payment() {
 819                 let event_handled = core::cell::RefCell::new(false);
 820                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 821
 822                 let payer = TestPayer::new();
 823                 let router = TestRouter {};
 824                 let scorer = RefCell::new(TestScorer::new());
 825                 let logger = TestLogger::new();
 826                 let invoice_payer =
 827                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(0));
 828
 829                 let payment_preimage = PaymentPreimage([1; 32]);
 830                 let invoice = invoice(payment_preimage);
 831                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 832
 833                 // Cannot repay an invoice pending payment.
 834                 match invoice_payer.pay_invoice(&invoice) {
 835                         Err(PaymentError::Invoice("payment pending")) => {},
 836                         Err(_) => panic!("unexpected error"),
 837                         Ok(_) => panic!("expected invoice error"),
 838                 }
 839
 840                 // Can repay an invoice once cleared from cache.
 841                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 842                 invoice_payer.remove_cached_payment(&payment_hash);
 843                 assert!(invoice_payer.pay_invoice(&invoice).is_ok());
 844
 845                 // Cannot retry paying an invoice if cleared from cache.
 846                 invoice_payer.remove_cached_payment(&payment_hash);
 847                 let event = Event::PaymentPathFailed {
 848                         payment_id,
 849                         payment_hash,
 850                         network_update: None,
 851                         rejected_by_dest: false,
 852                         all_paths_failed: false,
 853                         path: vec![],
 854                         short_channel_id: None,
 855                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 856                 };
 857                 invoice_payer.handle_event(&event);
 858                 assert_eq!(*event_handled.borrow(), true);
 859         }
 860
 861         #[test]
 862         fn fails_paying_invoice_with_routing_errors() {
 863                 let payer = TestPayer::new();
 864                 let router = FailingRouter {};
 865                 let scorer = RefCell::new(TestScorer::new());
 866                 let logger = TestLogger::new();
 867                 let invoice_payer =
 868                         InvoicePayer::new(&payer, router, &scorer, &logger, |_: &_| {}, RetryAttempts(0));
 869
 870                 let payment_preimage = PaymentPreimage([1; 32]);
 871                 let invoice = invoice(payment_preimage);
 872                 match invoice_payer.pay_invoice(&invoice) {
 873                         Err(PaymentError::Routing(_)) => {},
 874                         Err(_) => panic!("unexpected error"),
 875                         Ok(_) => panic!("expected routing error"),
 876                 }
 877         }
 878
 879         #[test]
 880         fn fails_paying_invoice_with_sending_errors() {
 881                 let payer = TestPayer::new().fails_on_attempt(1);
 882                 let router = TestRouter {};
 883                 let scorer = RefCell::new(TestScorer::new());
 884                 let logger = TestLogger::new();
 885                 let invoice_payer =
 886                         InvoicePayer::new(&payer, router, &scorer, &logger, |_: &_| {}, RetryAttempts(0));
 887
 888                 let payment_preimage = PaymentPreimage([1; 32]);
 889                 let invoice = invoice(payment_preimage);
 890                 match invoice_payer.pay_invoice(&invoice) {
 891                         Err(PaymentError::Sending(_)) => {},
 892                         Err(_) => panic!("unexpected error"),
 893                         Ok(_) => panic!("expected sending error"),
 894                 }
 895         }
 896
 897         #[test]
 898         fn pays_zero_value_invoice_using_amount() {
 899                 let event_handled = core::cell::RefCell::new(false);
 900                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 901
 902                 let payment_preimage = PaymentPreimage([1; 32]);
 903                 let invoice = zero_value_invoice(payment_preimage);
 904                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 905                 let final_value_msat = 100;
 906
 907                 let payer = TestPayer::new().expect_value_msat(final_value_msat);
 908                 let router = TestRouter {};
 909                 let scorer = RefCell::new(TestScorer::new());
 910                 let logger = TestLogger::new();
 911                 let invoice_payer =
 912                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(0));
 913
 914                 let payment_id =
 915                         Some(invoice_payer.pay_zero_value_invoice(&invoice, final_value_msat).unwrap());
 916                 assert_eq!(*payer.attempts.borrow(), 1);
 917
 918                 invoice_payer.handle_event(&Event::PaymentSent {
 919                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
 920                 });
 921                 assert_eq!(*event_handled.borrow(), true);
 922                 assert_eq!(*payer.attempts.borrow(), 1);
 923         }
 924
 925         #[test]
 926         fn fails_paying_zero_value_invoice_with_amount() {
 927                 let event_handled = core::cell::RefCell::new(false);
 928                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 929
 930                 let payer = TestPayer::new();
 931                 let router = TestRouter {};
 932                 let scorer = RefCell::new(TestScorer::new());
 933                 let logger = TestLogger::new();
 934                 let invoice_payer =
 935                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(0));
 936
 937                 let payment_preimage = PaymentPreimage([1; 32]);
 938                 let invoice = invoice(payment_preimage);
 939
 940                 // Cannot repay an invoice pending payment.
 941                 match invoice_payer.pay_zero_value_invoice(&invoice, 100) {
 942                         Err(PaymentError::Invoice("amount unexpected")) => {},
 943                         Err(_) => panic!("unexpected error"),
 944                         Ok(_) => panic!("expected invoice error"),
 945                 }
 946         }
 947
 948         #[test]
 949         fn scores_failed_channel() {
 950                 let event_handled = core::cell::RefCell::new(false);
 951                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 952
 953                 let payment_preimage = PaymentPreimage([1; 32]);
 954                 let invoice = invoice(payment_preimage);
 955                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 956                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 957                 let path = TestRouter::path_for_value(final_value_msat);
 958                 let short_channel_id = Some(path[0].short_channel_id);
 959
 960                 // Expect that scorer is given short_channel_id upon handling the event.
 961                 let payer = TestPayer::new();
 962                 let router = TestRouter {};
 963                 let scorer = RefCell::new(TestScorer::new().expect_channel_failure(short_channel_id.unwrap()));
 964                 let logger = TestLogger::new();
 965                 let invoice_payer =
 966                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 967
 968                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 969                 let event = Event::PaymentPathFailed {
 970                         payment_id,
 971                         payment_hash,
 972                         network_update: None,
 973                         rejected_by_dest: false,
 974                         all_paths_failed: false,
 975                         path,
 976                         short_channel_id,
 977                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 978                 };
 979                 invoice_payer.handle_event(&event);
 980         }
 981
 982         struct TestRouter;
 983
 984         impl TestRouter {
 985                 fn route_for_value(final_value_msat: u64) -> Route {
 986                         Route {
 987                                 paths: vec![
 988                                         vec![RouteHop {
 989                                                 pubkey: PublicKey::from_slice(&hex::decode("02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619").unwrap()[..]).unwrap(),
 990                                                 channel_features: ChannelFeatures::empty(),
 991                                                 node_features: NodeFeatures::empty(),
 992                                                 short_channel_id: 0, fee_msat: final_value_msat / 2, cltv_expiry_delta: 144
 993                                         }],
 994                                         vec![RouteHop {
 995                                                 pubkey: PublicKey::from_slice(&hex::decode("0324653eac434488002cc06bbfb7f10fe18991e35f9fe4302dbea6d2353dc0ab1c").unwrap()[..]).unwrap(),
 996                                                 channel_features: ChannelFeatures::empty(),
 997                                                 node_features: NodeFeatures::empty(),
 998                                                 short_channel_id: 1, fee_msat: final_value_msat / 2, cltv_expiry_delta: 144
 999                                         }],
1000                                 ],
1001                                 payee: None,
1002                         }
1003                 }
1004
1005                 fn path_for_value(final_value_msat: u64) -> Vec<RouteHop> {
1006                         TestRouter::route_for_value(final_value_msat).paths[0].clone()
1007                 }
1008
1009                 fn retry_for_invoice(invoice: &Invoice) -> RouteParameters {
1010                         let mut payee = Payee::new(invoice.recover_payee_pub_key())
1011                                 .with_expiry_time(expiry_time_from_unix_epoch(invoice).as_secs())
1012                                 .with_route_hints(invoice.route_hints());
1013                         if let Some(features) = invoice.features() {
1014                                 payee = payee.with_features(features.clone());
1015                         }
1016                         let final_value_msat = invoice.amount_milli_satoshis().unwrap() / 2;
1017                         RouteParameters {
1018                                 payee,
1019                                 final_value_msat,
1020                                 final_cltv_expiry_delta: invoice.min_final_cltv_expiry() as u32,
1021                         }
1022                 }
1023         }
1024
1025         impl<S: routing::Score> Router<S> for TestRouter {
1026                 fn find_route(
1027                         &self,
1028                         _payer: &PublicKey,
1029                         params: &RouteParameters,
1030                         _first_hops: Option<&[&ChannelDetails]>,
1031                         _scorer: &S,
1032                 ) -> Result<Route, LightningError> {
1033                         Ok(Route {
1034                                 payee: Some(params.payee.clone()), ..Self::route_for_value(params.final_value_msat)
1035                         })
1036                 }
1037         }
1038
1039         struct FailingRouter;
1040
1041         impl<S: routing::Score> Router<S> for FailingRouter {
1042                 fn find_route(
1043                         &self,
1044                         _payer: &PublicKey,
1045                         _params: &RouteParameters,
1046                         _first_hops: Option<&[&ChannelDetails]>,
1047                         _scorer: &S,
1048                 ) -> Result<Route, LightningError> {
1049                         Err(LightningError { err: String::new(), action: ErrorAction::IgnoreError })
1050                 }
1051         }
1052
1053         struct TestScorer {
1054                 expectations: VecDeque<u64>,
1055         }
1056
1057         impl TestScorer {
1058                 fn new() -> Self {
1059                         Self {
1060                                 expectations: VecDeque::new(),
1061                         }
1062                 }
1063
1064                 fn expect_channel_failure(mut self, short_channel_id: u64) -> Self {
1065                         self.expectations.push_back(short_channel_id);
1066                         self
1067                 }
1068         }
1069
1070         impl routing::Score for TestScorer {
1071                 fn channel_penalty_msat(
1072                         &self, _short_channel_id: u64, _source: &NodeId, _target: &NodeId
1073                 ) -> u64 { 0 }
1074
1075                 fn payment_path_failed(&mut self, _path: &Vec<RouteHop>, short_channel_id: u64) {
1076                         if let Some(expected_short_channel_id) = self.expectations.pop_front() {
1077                                 assert_eq!(short_channel_id, expected_short_channel_id);
1078                         }
1079                 }
1080         }
1081
1082         impl Drop for TestScorer {
1083                 fn drop(&mut self) {
1084                         if std::thread::panicking() {
1085                                 return;
1086                         }
1087
1088                         if !self.expectations.is_empty() {
1089                                 panic!("Unsatisfied channel failure expectations: {:?}", self.expectations);
1090                         }
1091                 }
1092         }
1093
1094         struct TestPayer {
1095                 expectations: core::cell::RefCell<VecDeque<u64>>,
1096                 attempts: core::cell::RefCell<usize>,
1097                 failing_on_attempt: Option<usize>,
1098         }
1099
1100         impl TestPayer {
1101                 fn new() -> Self {
1102                         Self {
1103                                 expectations: core::cell::RefCell::new(VecDeque::new()),
1104                                 attempts: core::cell::RefCell::new(0),
1105                                 failing_on_attempt: None,
1106                         }
1107                 }
1108
1109                 fn expect_value_msat(self, value_msat: u64) -> Self {
1110                         self.expectations.borrow_mut().push_back(value_msat);
1111                         self
1112                 }
1113
1114                 fn fails_on_attempt(self, attempt: usize) -> Self {
1115                         Self {
1116                                 expectations: core::cell::RefCell::new(self.expectations.borrow().clone()),
1117                                 attempts: core::cell::RefCell::new(0),
1118                                 failing_on_attempt: Some(attempt),
1119                         }
1120                 }
1121
1122                 fn check_attempts(&self) -> bool {
1123                         let mut attempts = self.attempts.borrow_mut();
1124                         *attempts += 1;
1125                         match self.failing_on_attempt {
1126                                 None => true,
1127                                 Some(attempt) if attempt != *attempts => true,
1128                                 Some(_) => false,
1129                         }
1130                 }
1131
1132                 fn check_value_msats(&self, route: &Route) {
1133                         let expected_value_msats = self.expectations.borrow_mut().pop_front();
1134                         if let Some(expected_value_msats) = expected_value_msats {
1135                                 let actual_value_msats = route.get_total_amount();
1136                                 assert_eq!(actual_value_msats, expected_value_msats);
1137                         }
1138                 }
1139         }
1140
1141         impl Drop for TestPayer {
1142                 fn drop(&mut self) {
1143                         if std::thread::panicking() {
1144                                 return;
1145                         }
1146
1147                         if !self.expectations.borrow().is_empty() {
1148                                 panic!("Unsatisfied payment expectations: {:?}", self.expectations.borrow());
1149                         }
1150                 }
1151         }
1152
1153         impl Payer for TestPayer {
1154                 fn node_id(&self) -> PublicKey {
1155                         let secp_ctx = Secp256k1::new();
1156                         PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap())
1157                 }
1158
1159                 fn first_hops(&self) -> Vec<ChannelDetails> {
1160                         Vec::new()
1161                 }
1162
1163                 fn send_payment(
1164                         &self,
1165                         route: &Route,
1166                         _payment_hash: PaymentHash,
1167                         _payment_secret: &Option<PaymentSecret>
1168                 ) -> Result<PaymentId, PaymentSendFailure> {
1169                         if self.check_attempts() {
1170                                 self.check_value_msats(route);
1171                                 Ok(PaymentId([1; 32]))
1172                         } else {
1173                                 Err(PaymentSendFailure::ParameterError(APIError::MonitorUpdateFailed))
1174                         }
1175                 }
1176
1177                 fn retry_payment(
1178                         &self, route: &Route, _payment_id: PaymentId
1179                 ) -> Result<(), PaymentSendFailure> {
1180                         if self.check_attempts() {
1181                                 self.check_value_msats(route);
1182                                 Ok(())
1183                         } else {
1184                                 Err(PaymentSendFailure::ParameterError(APIError::MonitorUpdateFailed))
1185                         }
1186                 }
1187         }
1188
1189         // *** Full Featured Functional Tests with a Real ChannelManager ***
1190         struct ManualRouter(RefCell<VecDeque<Result<Route, LightningError>>>);
1191
1192         impl<S: routing::Score> Router<S> for ManualRouter {
1193                 fn find_route(&self, _payer: &PublicKey, _params: &RouteParameters, _first_hops: Option<&[&ChannelDetails]>, _scorer: &S)
1194                 -> Result<Route, LightningError> {
1195                         self.0.borrow_mut().pop_front().unwrap()
1196                 }
1197         }
1198         impl ManualRouter {
1199                 fn expect_find_route(&self, result: Result<Route, LightningError>) {
1200                         self.0.borrow_mut().push_back(result);
1201                 }
1202         }
1203         impl Drop for ManualRouter {
1204                 fn drop(&mut self) {
1205                         if std::thread::panicking() {
1206                                 return;
1207                         }
1208                         assert!(self.0.borrow_mut().is_empty());
1209                 }
1210         }
1211
1212         #[test]
1213         fn retry_multi_path_single_failed_payment() {
1214                 // Tests that we can/will retry after a single path of an MPP payment failed immediately
1215                 let chanmon_cfgs = create_chanmon_cfgs(2);
1216                 let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
1217                 let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None, None]);
1218                 let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
1219
1220                 create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0, InitFeatures::known(), InitFeatures::known());
1221                 create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0, InitFeatures::known(), InitFeatures::known());
1222                 let chans = nodes[0].node.list_usable_channels();
1223                 let mut route = Route {
1224                         paths: vec![
1225                                 vec![RouteHop {
1226                                         pubkey: nodes[1].node.get_our_node_id(),
1227                                         node_features: NodeFeatures::known(),
1228                                         short_channel_id: chans[0].short_channel_id.unwrap(),
1229                                         channel_features: ChannelFeatures::known(),
1230                                         fee_msat: 10_000,
1231                                         cltv_expiry_delta: 100,
1232                                 }],
1233                                 vec![RouteHop {
1234                                         pubkey: nodes[1].node.get_our_node_id(),
1235                                         node_features: NodeFeatures::known(),
1236                                         short_channel_id: chans[1].short_channel_id.unwrap(),
1237                                         channel_features: ChannelFeatures::known(),
1238                                         fee_msat: 100_000_001, // Our default max-HTLC-value is 10% of the channel value, which this is one more than
1239                                         cltv_expiry_delta: 100,
1240                                 }],
1241                         ],
1242                         payee: Some(Payee::new(nodes[1].node.get_our_node_id())),
1243                 };
1244                 let router = ManualRouter(RefCell::new(VecDeque::new()));
1245                 router.expect_find_route(Ok(route.clone()));
1246                 // On retry, split the payment across both channels.
1247                 route.paths[0][0].fee_msat = 50_000_001;
1248                 route.paths[1][0].fee_msat = 50_000_000;
1249                 router.expect_find_route(Ok(route.clone()));
1250
1251                 let event_handler = |_: &_| { panic!(); };
1252                 let scorer = RefCell::new(TestScorer::new());
1253                 let invoice_payer = InvoicePayer::new(nodes[0].node, router, &scorer, nodes[0].logger, event_handler, RetryAttempts(1));
1254
1255                 assert!(invoice_payer.pay_invoice(&create_invoice_from_channelmanager(
1256                         &nodes[1].node, nodes[1].keys_manager, Currency::Bitcoin, Some(100_010_000), "Invoice".to_string()).unwrap())
1257                         .is_ok());
1258                 let htlc_msgs = nodes[0].node.get_and_clear_pending_msg_events();
1259                 assert_eq!(htlc_msgs.len(), 2);
1260                 check_added_monitors!(nodes[0], 2);
1261         }
1262
1263         #[test]
1264         fn immediate_retry_on_failure() {
1265                 // Tests that we can/will retry immediately after a failure
1266                 let chanmon_cfgs = create_chanmon_cfgs(2);
1267                 let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
1268                 let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None, None]);
1269                 let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
1270
1271                 create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0, InitFeatures::known(), InitFeatures::known());
1272                 create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0, InitFeatures::known(), InitFeatures::known());
1273                 let chans = nodes[0].node.list_usable_channels();
1274                 let mut route = Route {
1275                         paths: vec![
1276                                 vec![RouteHop {
1277                                         pubkey: nodes[1].node.get_our_node_id(),
1278                                         node_features: NodeFeatures::known(),
1279                                         short_channel_id: chans[0].short_channel_id.unwrap(),
1280                                         channel_features: ChannelFeatures::known(),
1281                                         fee_msat: 100_000_001, // Our default max-HTLC-value is 10% of the channel value, which this is one more than
1282                                         cltv_expiry_delta: 100,
1283                                 }],
1284                         ],
1285                         payee: Some(Payee::new(nodes[1].node.get_our_node_id())),
1286                 };
1287                 let router = ManualRouter(RefCell::new(VecDeque::new()));
1288                 router.expect_find_route(Ok(route.clone()));
1289                 // On retry, split the payment across both channels.
1290                 route.paths.push(route.paths[0].clone());
1291                 route.paths[0][0].short_channel_id = chans[1].short_channel_id.unwrap();
1292                 route.paths[0][0].fee_msat = 50_000_000;
1293                 route.paths[1][0].fee_msat = 50_000_001;
1294                 router.expect_find_route(Ok(route.clone()));
1295
1296                 let event_handler = |_: &_| { panic!(); };
1297                 let scorer = RefCell::new(TestScorer::new());
1298                 let invoice_payer = InvoicePayer::new(nodes[0].node, router, &scorer, nodes[0].logger, event_handler, RetryAttempts(1));
1299
1300                 assert!(invoice_payer.pay_invoice(&create_invoice_from_channelmanager(
1301                         &nodes[1].node, nodes[1].keys_manager, Currency::Bitcoin, Some(100_010_000), "Invoice".to_string()).unwrap())
1302                         .is_ok());
1303                 let htlc_msgs = nodes[0].node.get_and_clear_pending_msg_events();
1304                 assert_eq!(htlc_msgs.len(), 2);
1305                 check_added_monitors!(nodes[0], 2);
1306         }
1307 }