_ 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: &[&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                 if invoice.is_expired() {
 257                         log_trace!(self.logger, "Invoice expired prior to first send for payment {}", log_bytes!(payment_hash.0));
 258                         return Err(PaymentError::Invoice("Invoice expired prior to send"));
 259                 }
 260                 let retry_data_payment_id = loop {
 261                         let mut payment_cache = self.payment_cache.lock().unwrap();
 262                         match payment_cache.entry(payment_hash) {
 263                                 hash_map::Entry::Vacant(entry) => {
 264                                         let payer = self.payer.node_id();
 265                                         let mut payee = Payee::from_node_id(invoice.recover_payee_pub_key())
 266                                                 .with_expiry_time(expiry_time_from_unix_epoch(&invoice).as_secs())
 267                                                 .with_route_hints(invoice.route_hints());
 268                                         if let Some(features) = invoice.features() {
 269                                                 payee = payee.with_features(features.clone());
 270                                         }
 271                                         let params = RouteParameters {
 272                                                 payee,
 273                                                 final_value_msat: invoice.amount_milli_satoshis().or(amount_msats).unwrap(),
 274                                                 final_cltv_expiry_delta: invoice.min_final_cltv_expiry() as u32,
 275                                         };
 276                                         let first_hops = self.payer.first_hops();
 277                                         let route = self.router.find_route(
 278                                                 &payer,
 279                                                 &params,
 280                                                 Some(&first_hops.iter().collect::<Vec<_>>()),
 281                                                 &self.scorer.lock(),
 282                                         ).map_err(|e| PaymentError::Routing(e))?;
 283
 284                                         let payment_secret = Some(invoice.payment_secret().clone());
 285                                         let payment_id = match self.payer.send_payment(&route, payment_hash, &payment_secret) {
 286                                                 Ok(payment_id) => payment_id,
 287                                                 Err(PaymentSendFailure::ParameterError(e)) =>
 288                                                         return Err(PaymentError::Sending(PaymentSendFailure::ParameterError(e))),
 289                                                 Err(PaymentSendFailure::PathParameterError(e)) =>
 290                                                         return Err(PaymentError::Sending(PaymentSendFailure::PathParameterError(e))),
 291                                                 Err(PaymentSendFailure::AllFailedRetrySafe(e)) => {
 292                                                         if retry_count >= self.retry_attempts.0 {
 293                                                                 return Err(PaymentError::Sending(PaymentSendFailure::AllFailedRetrySafe(e)))
 294                                                         }
 295                                                         break None;
 296                                                 },
 297                                                 Err(PaymentSendFailure::PartialFailure { results: _, failed_paths_retry, payment_id }) => {
 298                                                         if let Some(retry_data) = failed_paths_retry {
 299                                                                 entry.insert(retry_count);
 300                                                                 break Some((retry_data, payment_id));
 301                                                         } else {
 302                                                                 // This may happen if we send a payment and some paths fail, but
 303                                                                 // only due to a temporary monitor failure or the like, implying
 304                                                                 // they're really in-flight, but we haven't sent the initial
 305                                                                 // HTLC-Add messages yet.
 306                                                                 payment_id
 307                                                         }
 308                                                 },
 309                                         };
 310                                         entry.insert(retry_count);
 311                                         return Ok(payment_id);
 312                                 },
 313                                 hash_map::Entry::Occupied(_) => return Err(PaymentError::Invoice("payment pending")),
 314                         }
 315                 };
 316                 if let Some((retry_data, payment_id)) = retry_data_payment_id {
 317                         // Some paths were sent, even if we failed to send the full MPP value our recipient may
 318                         // misbehave and claim the funds, at which point we have to consider the payment sent,
 319                         // so return `Ok()` here, ignoring any retry errors.
 320                         let _ = self.retry_payment(payment_id, payment_hash, &retry_data);
 321                         Ok(payment_id)
 322                 } else {
 323                         self.pay_invoice_internal(invoice, amount_msats, retry_count + 1)
 324                 }
 325         }
 326
 327         fn retry_payment(&self, payment_id: PaymentId, payment_hash: PaymentHash, params: &RouteParameters)
 328         -> Result<(), ()> {
 329                 let route;
 330                 {
 331                         let mut payment_cache = self.payment_cache.lock().unwrap();
 332                         let entry = loop {
 333                                 let entry = payment_cache.entry(payment_hash);
 334                                 match entry {
 335                                         hash_map::Entry::Occupied(_) => break entry,
 336                                         hash_map::Entry::Vacant(entry) => entry.insert(0),
 337                                 };
 338                         };
 339                         if let hash_map::Entry::Occupied(mut entry) = entry {
 340                                 let max_payment_attempts = self.retry_attempts.0 + 1;
 341                                 let attempts = entry.get_mut();
 342                                 *attempts += 1;
 343
 344                                 if *attempts >= max_payment_attempts {
 345                                         log_trace!(self.logger, "Payment {} exceeded maximum attempts; not retrying (attempts: {})", log_bytes!(payment_hash.0), attempts);
 346                                         return Err(());
 347                                 } else if has_expired(params) {
 348                                         log_trace!(self.logger, "Invoice expired for payment {}; not retrying (attempts: {})", log_bytes!(payment_hash.0), attempts);
 349                                         return Err(());
 350                                 }
 351
 352                                 let payer = self.payer.node_id();
 353                                 let first_hops = self.payer.first_hops();
 354                                 route = self.router.find_route(&payer, &params, Some(&first_hops.iter().collect::<Vec<_>>()), &self.scorer.lock());
 355                                 if route.is_err() {
 356                                         log_trace!(self.logger, "Failed to find a route for payment {}; not retrying (attempts: {})", log_bytes!(payment_hash.0), attempts);
 357                                         return Err(());
 358                                 }
 359                         } else {
 360                                 unreachable!();
 361                         }
 362                 }
 363
 364                 let retry_res = self.payer.retry_payment(&route.unwrap(), payment_id);
 365                 match retry_res {
 366                         Ok(()) => Ok(()),
 367                         Err(PaymentSendFailure::ParameterError(_)) |
 368                         Err(PaymentSendFailure::PathParameterError(_)) => {
 369                                 log_trace!(self.logger, "Failed to retry for payment {} due to bogus route/payment data, not retrying.", log_bytes!(payment_hash.0));
 370                                 return Err(());
 371                         },
 372                         Err(PaymentSendFailure::AllFailedRetrySafe(_)) => {
 373                                 self.retry_payment(payment_id, payment_hash, params)
 374                         },
 375                         Err(PaymentSendFailure::PartialFailure { results: _, failed_paths_retry, .. }) => {
 376                                 if let Some(retry) = failed_paths_retry {
 377                                         self.retry_payment(payment_id, payment_hash, &retry)
 378                                 } else {
 379                                         Ok(())
 380                                 }
 381                         },
 382                 }
 383         }
 384
 385         /// Removes the payment cached by the given payment hash.
 386         ///
 387         /// Should be called once a payment has failed or succeeded if not using [`InvoicePayer`] as an
 388         /// [`EventHandler`]. Otherwise, calling this method is unnecessary.
 389         pub fn remove_cached_payment(&self, payment_hash: &PaymentHash) {
 390                 self.payment_cache.lock().unwrap().remove(payment_hash);
 391         }
 392 }
 393
 394 fn expiry_time_from_unix_epoch(invoice: &Invoice) -> Duration {
 395         invoice.timestamp().duration_since(SystemTime::UNIX_EPOCH).unwrap() + invoice.expiry_time()
 396 }
 397
 398 fn has_expired(params: &RouteParameters) -> bool {
 399         if let Some(expiry_time) = params.payee.expiry_time {
 400                 Invoice::is_expired_from_epoch(&SystemTime::UNIX_EPOCH, Duration::from_secs(expiry_time))
 401         } else { false }
 402 }
 403
 404 impl<P: Deref, R, S: Deref, L: Deref, E> EventHandler for InvoicePayer<P, R, S, L, E>
 405 where
 406         P::Target: Payer,
 407         R: for <'a> Router<<<S as Deref>::Target as routing::LockableScore<'a>>::Locked>,
 408         S::Target: for <'a> routing::LockableScore<'a>,
 409         L::Target: Logger,
 410         E: EventHandler,
 411 {
 412         fn handle_event(&self, event: &Event) {
 413                 match event {
 414                         Event::PaymentPathFailed {
 415                                 all_paths_failed, payment_id, payment_hash, rejected_by_dest, path, short_channel_id, retry, ..
 416                         } => {
 417                                 if let Some(short_channel_id) = short_channel_id {
 418                                         let t = path.iter().collect::<Vec<_>>();
 419                                         self.scorer.lock().payment_path_failed(&t, *short_channel_id);
 420                                 }
 421
 422                                 if *rejected_by_dest {
 423                                         log_trace!(self.logger, "Payment {} rejected by destination; not retrying", log_bytes!(payment_hash.0));
 424                                 } else if payment_id.is_none() {
 425                                         log_trace!(self.logger, "Payment {} has no id; not retrying", log_bytes!(payment_hash.0));
 426                                 } else if let Some(params) = retry {
 427                                         if self.retry_payment(payment_id.unwrap(), *payment_hash, params).is_ok() {
 428                                                 // We retried at least somewhat, don't provide the PaymentPathFailed event to the user.
 429                                                 return;
 430                                         }
 431                                 } else {
 432                                         log_trace!(self.logger, "Payment {} missing retry params; not retrying", log_bytes!(payment_hash.0));
 433                                 }
 434                                 if *all_paths_failed { self.payment_cache.lock().unwrap().remove(payment_hash); }
 435                         },
 436                         Event::PaymentSent { payment_hash, .. } => {
 437                                 let mut payment_cache = self.payment_cache.lock().unwrap();
 438                                 let attempts = payment_cache
 439                                         .remove(payment_hash)
 440                                         .map_or(1, |attempts| attempts + 1);
 441                                 log_trace!(self.logger, "Payment {} succeeded (attempts: {})", log_bytes!(payment_hash.0), attempts);
 442                         },
 443                         _ => {},
 444                 }
 445
 446                 // Delegate to the decorated event handler unless the payment is retried.
 447                 self.event_handler.handle_event(event)
 448         }
 449 }
 450
 451 #[cfg(test)]
 452 mod tests {
 453         use super::*;
 454         use crate::{DEFAULT_EXPIRY_TIME, InvoiceBuilder, Currency};
 455         use utils::create_invoice_from_channelmanager;
 456         use bitcoin_hashes::sha256::Hash as Sha256;
 457         use lightning::ln::PaymentPreimage;
 458         use lightning::ln::features::{ChannelFeatures, NodeFeatures, InitFeatures};
 459         use lightning::ln::functional_test_utils::*;
 460         use lightning::ln::msgs::{ErrorAction, LightningError};
 461         use lightning::routing::network_graph::NodeId;
 462         use lightning::routing::router::{Payee, Route, RouteHop};
 463         use lightning::util::test_utils::TestLogger;
 464         use lightning::util::errors::APIError;
 465         use lightning::util::events::{Event, MessageSendEventsProvider};
 466         use secp256k1::{SecretKey, PublicKey, Secp256k1};
 467         use std::cell::RefCell;
 468         use std::collections::VecDeque;
 469         use std::time::{SystemTime, Duration};
 470
 471         fn invoice(payment_preimage: PaymentPreimage) -> Invoice {
 472                 let payment_hash = Sha256::hash(&payment_preimage.0);
 473                 let private_key = SecretKey::from_slice(&[42; 32]).unwrap();
 474                 InvoiceBuilder::new(Currency::Bitcoin)
 475                         .description("test".into())
 476                         .payment_hash(payment_hash)
 477                         .payment_secret(PaymentSecret([0; 32]))
 478                         .current_timestamp()
 479                         .min_final_cltv_expiry(144)
 480                         .amount_milli_satoshis(128)
 481                         .build_signed(|hash| {
 482                                 Secp256k1::new().sign_recoverable(hash, &private_key)
 483                         })
 484                         .unwrap()
 485         }
 486
 487         fn zero_value_invoice(payment_preimage: PaymentPreimage) -> Invoice {
 488                 let payment_hash = Sha256::hash(&payment_preimage.0);
 489                 let private_key = SecretKey::from_slice(&[42; 32]).unwrap();
 490                 InvoiceBuilder::new(Currency::Bitcoin)
 491                         .description("test".into())
 492                         .payment_hash(payment_hash)
 493                         .payment_secret(PaymentSecret([0; 32]))
 494                         .current_timestamp()
 495                         .min_final_cltv_expiry(144)
 496                         .build_signed(|hash| {
 497                                 Secp256k1::new().sign_recoverable(hash, &private_key)
 498                         })
 499                         .unwrap()
 500         }
 501
 502         fn expired_invoice(payment_preimage: PaymentPreimage) -> Invoice {
 503                 let payment_hash = Sha256::hash(&payment_preimage.0);
 504                 let private_key = SecretKey::from_slice(&[42; 32]).unwrap();
 505                 let timestamp = SystemTime::now()
 506                         .checked_sub(Duration::from_secs(DEFAULT_EXPIRY_TIME * 2))
 507                         .unwrap();
 508                 InvoiceBuilder::new(Currency::Bitcoin)
 509                         .description("test".into())
 510                         .payment_hash(payment_hash)
 511                         .payment_secret(PaymentSecret([0; 32]))
 512                         .timestamp(timestamp)
 513                         .min_final_cltv_expiry(144)
 514                         .amount_milli_satoshis(128)
 515                         .build_signed(|hash| {
 516                                 Secp256k1::new().sign_recoverable(hash, &private_key)
 517                         })
 518                         .unwrap()
 519         }
 520
 521         #[test]
 522         fn pays_invoice_on_first_attempt() {
 523                 let event_handled = core::cell::RefCell::new(false);
 524                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 525
 526                 let payment_preimage = PaymentPreimage([1; 32]);
 527                 let invoice = invoice(payment_preimage);
 528                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 529
 530                 let payer = TestPayer::new();
 531                 let router = TestRouter {};
 532                 let scorer = RefCell::new(TestScorer::new());
 533                 let logger = TestLogger::new();
 534                 let invoice_payer =
 535                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(0));
 536
 537                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 538                 assert_eq!(*payer.attempts.borrow(), 1);
 539
 540                 invoice_payer.handle_event(&Event::PaymentSent {
 541                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
 542                 });
 543                 assert_eq!(*event_handled.borrow(), true);
 544                 assert_eq!(*payer.attempts.borrow(), 1);
 545         }
 546
 547         #[test]
 548         fn pays_invoice_on_retry() {
 549                 let event_handled = core::cell::RefCell::new(false);
 550                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 551
 552                 let payment_preimage = PaymentPreimage([1; 32]);
 553                 let invoice = invoice(payment_preimage);
 554                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 555                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 556
 557                 let payer = TestPayer::new()
 558                         .expect_value_msat(final_value_msat)
 559                         .expect_value_msat(final_value_msat / 2);
 560                 let router = TestRouter {};
 561                 let scorer = RefCell::new(TestScorer::new());
 562                 let logger = TestLogger::new();
 563                 let invoice_payer =
 564                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 565
 566                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 567                 assert_eq!(*payer.attempts.borrow(), 1);
 568
 569                 let event = Event::PaymentPathFailed {
 570                         payment_id,
 571                         payment_hash,
 572                         network_update: None,
 573                         rejected_by_dest: false,
 574                         all_paths_failed: false,
 575                         path: TestRouter::path_for_value(final_value_msat),
 576                         short_channel_id: None,
 577                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 578                 };
 579                 invoice_payer.handle_event(&event);
 580                 assert_eq!(*event_handled.borrow(), false);
 581                 assert_eq!(*payer.attempts.borrow(), 2);
 582
 583                 invoice_payer.handle_event(&Event::PaymentSent {
 584                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
 585                 });
 586                 assert_eq!(*event_handled.borrow(), true);
 587                 assert_eq!(*payer.attempts.borrow(), 2);
 588         }
 589
 590         #[test]
 591         fn retries_payment_path_for_unknown_payment() {
 592                 let event_handled = core::cell::RefCell::new(false);
 593                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 594
 595                 let payment_preimage = PaymentPreimage([1; 32]);
 596                 let invoice = invoice(payment_preimage);
 597                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 598                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 599
 600                 let payer = TestPayer::new();
 601                 let router = TestRouter {};
 602                 let scorer = RefCell::new(TestScorer::new());
 603                 let logger = TestLogger::new();
 604                 let invoice_payer =
 605                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 606
 607                 let payment_id = Some(PaymentId([1; 32]));
 608                 let event = Event::PaymentPathFailed {
 609                         payment_id,
 610                         payment_hash,
 611                         network_update: None,
 612                         rejected_by_dest: false,
 613                         all_paths_failed: false,
 614                         path: TestRouter::path_for_value(final_value_msat),
 615                         short_channel_id: None,
 616                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 617                 };
 618                 invoice_payer.handle_event(&event);
 619                 assert_eq!(*event_handled.borrow(), false);
 620                 assert_eq!(*payer.attempts.borrow(), 1);
 621
 622                 invoice_payer.handle_event(&event);
 623                 assert_eq!(*event_handled.borrow(), false);
 624                 assert_eq!(*payer.attempts.borrow(), 2);
 625
 626                 invoice_payer.handle_event(&Event::PaymentSent {
 627                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
 628                 });
 629                 assert_eq!(*event_handled.borrow(), true);
 630                 assert_eq!(*payer.attempts.borrow(), 2);
 631         }
 632
 633         #[test]
 634         fn fails_paying_invoice_after_max_retries() {
 635                 let event_handled = core::cell::RefCell::new(false);
 636                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 637
 638                 let payment_preimage = PaymentPreimage([1; 32]);
 639                 let invoice = invoice(payment_preimage);
 640                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 641
 642                 let payer = TestPayer::new()
 643                         .expect_value_msat(final_value_msat)
 644                         .expect_value_msat(final_value_msat / 2)
 645                         .expect_value_msat(final_value_msat / 2);
 646                 let router = TestRouter {};
 647                 let scorer = RefCell::new(TestScorer::new());
 648                 let logger = TestLogger::new();
 649                 let invoice_payer =
 650                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 651
 652                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 653                 assert_eq!(*payer.attempts.borrow(), 1);
 654
 655                 let event = Event::PaymentPathFailed {
 656                         payment_id,
 657                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 658                         network_update: None,
 659                         rejected_by_dest: false,
 660                         all_paths_failed: true,
 661                         path: TestRouter::path_for_value(final_value_msat),
 662                         short_channel_id: None,
 663                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 664                 };
 665                 invoice_payer.handle_event(&event);
 666                 assert_eq!(*event_handled.borrow(), false);
 667                 assert_eq!(*payer.attempts.borrow(), 2);
 668
 669                 let event = Event::PaymentPathFailed {
 670                         payment_id,
 671                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 672                         network_update: None,
 673                         rejected_by_dest: false,
 674                         all_paths_failed: false,
 675                         path: TestRouter::path_for_value(final_value_msat / 2),
 676                         short_channel_id: None,
 677                         retry: Some(RouteParameters {
 678                                 final_value_msat: final_value_msat / 2, ..TestRouter::retry_for_invoice(&invoice)
 679                         }),
 680                 };
 681                 invoice_payer.handle_event(&event);
 682                 assert_eq!(*event_handled.borrow(), false);
 683                 assert_eq!(*payer.attempts.borrow(), 3);
 684
 685                 invoice_payer.handle_event(&event);
 686                 assert_eq!(*event_handled.borrow(), true);
 687                 assert_eq!(*payer.attempts.borrow(), 3);
 688         }
 689
 690         #[test]
 691         fn fails_paying_invoice_with_missing_retry_params() {
 692                 let event_handled = core::cell::RefCell::new(false);
 693                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 694
 695                 let payer = TestPayer::new();
 696                 let router = TestRouter {};
 697                 let scorer = RefCell::new(TestScorer::new());
 698                 let logger = TestLogger::new();
 699                 let invoice_payer =
 700                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 701
 702                 let payment_preimage = PaymentPreimage([1; 32]);
 703                 let invoice = invoice(payment_preimage);
 704                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 705                 assert_eq!(*payer.attempts.borrow(), 1);
 706
 707                 let event = Event::PaymentPathFailed {
 708                         payment_id,
 709                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 710                         network_update: None,
 711                         rejected_by_dest: false,
 712                         all_paths_failed: false,
 713                         path: vec![],
 714                         short_channel_id: None,
 715                         retry: None,
 716                 };
 717                 invoice_payer.handle_event(&event);
 718                 assert_eq!(*event_handled.borrow(), true);
 719                 assert_eq!(*payer.attempts.borrow(), 1);
 720         }
 721
 722         #[test]
 723         fn fails_paying_invoice_after_expiration() {
 724                 let event_handled = core::cell::RefCell::new(false);
 725                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 726
 727                 let payer = TestPayer::new();
 728                 let router = TestRouter {};
 729                 let scorer = RefCell::new(TestScorer::new());
 730                 let logger = TestLogger::new();
 731                 let invoice_payer =
 732                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 733
 734                 let payment_preimage = PaymentPreimage([1; 32]);
 735                 let invoice = expired_invoice(payment_preimage);
 736                 if let PaymentError::Invoice(msg) = invoice_payer.pay_invoice(&invoice).unwrap_err() {
 737                         assert_eq!(msg, "Invoice expired prior to send");
 738                 } else { panic!("Expected Invoice Error"); }
 739         }
 740
 741         #[test]
 742         fn fails_retrying_invoice_after_expiration() {
 743                 let event_handled = core::cell::RefCell::new(false);
 744                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 745
 746                 let payer = TestPayer::new();
 747                 let router = TestRouter {};
 748                 let scorer = RefCell::new(TestScorer::new());
 749                 let logger = TestLogger::new();
 750                 let invoice_payer =
 751                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 752
 753                 let payment_preimage = PaymentPreimage([1; 32]);
 754                 let invoice = invoice(payment_preimage);
 755                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 756                 assert_eq!(*payer.attempts.borrow(), 1);
 757
 758                 let mut retry_data = TestRouter::retry_for_invoice(&invoice);
 759                 retry_data.payee.expiry_time = Some(SystemTime::now()
 760                         .checked_sub(Duration::from_secs(2)).unwrap()
 761                         .duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs());
 762                 let event = Event::PaymentPathFailed {
 763                         payment_id,
 764                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 765                         network_update: None,
 766                         rejected_by_dest: false,
 767                         all_paths_failed: false,
 768                         path: vec![],
 769                         short_channel_id: None,
 770                         retry: Some(retry_data),
 771                 };
 772                 invoice_payer.handle_event(&event);
 773                 assert_eq!(*event_handled.borrow(), true);
 774                 assert_eq!(*payer.attempts.borrow(), 1);
 775         }
 776
 777         #[test]
 778         fn fails_paying_invoice_after_retry_error() {
 779                 let event_handled = core::cell::RefCell::new(false);
 780                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 781
 782                 let payment_preimage = PaymentPreimage([1; 32]);
 783                 let invoice = invoice(payment_preimage);
 784                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 785
 786                 let payer = TestPayer::new()
 787                         .fails_on_attempt(2)
 788                         .expect_value_msat(final_value_msat);
 789                 let router = TestRouter {};
 790                 let scorer = RefCell::new(TestScorer::new());
 791                 let logger = TestLogger::new();
 792                 let invoice_payer =
 793                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 794
 795                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 796                 assert_eq!(*payer.attempts.borrow(), 1);
 797
 798                 let event = Event::PaymentPathFailed {
 799                         payment_id,
 800                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 801                         network_update: None,
 802                         rejected_by_dest: false,
 803                         all_paths_failed: false,
 804                         path: TestRouter::path_for_value(final_value_msat / 2),
 805                         short_channel_id: None,
 806                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 807                 };
 808                 invoice_payer.handle_event(&event);
 809                 assert_eq!(*event_handled.borrow(), true);
 810                 assert_eq!(*payer.attempts.borrow(), 2);
 811         }
 812
 813         #[test]
 814         fn fails_paying_invoice_after_rejected_by_payee() {
 815                 let event_handled = core::cell::RefCell::new(false);
 816                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 817
 818                 let payer = TestPayer::new();
 819                 let router = TestRouter {};
 820                 let scorer = RefCell::new(TestScorer::new());
 821                 let logger = TestLogger::new();
 822                 let invoice_payer =
 823                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 824
 825                 let payment_preimage = PaymentPreimage([1; 32]);
 826                 let invoice = invoice(payment_preimage);
 827                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 828                 assert_eq!(*payer.attempts.borrow(), 1);
 829
 830                 let event = Event::PaymentPathFailed {
 831                         payment_id,
 832                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 833                         network_update: None,
 834                         rejected_by_dest: true,
 835                         all_paths_failed: false,
 836                         path: vec![],
 837                         short_channel_id: None,
 838                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 839                 };
 840                 invoice_payer.handle_event(&event);
 841                 assert_eq!(*event_handled.borrow(), true);
 842                 assert_eq!(*payer.attempts.borrow(), 1);
 843         }
 844
 845         #[test]
 846         fn fails_repaying_invoice_with_pending_payment() {
 847                 let event_handled = core::cell::RefCell::new(false);
 848                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 849
 850                 let payer = TestPayer::new();
 851                 let router = TestRouter {};
 852                 let scorer = RefCell::new(TestScorer::new());
 853                 let logger = TestLogger::new();
 854                 let invoice_payer =
 855                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(0));
 856
 857                 let payment_preimage = PaymentPreimage([1; 32]);
 858                 let invoice = invoice(payment_preimage);
 859                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 860
 861                 // Cannot repay an invoice pending payment.
 862                 match invoice_payer.pay_invoice(&invoice) {
 863                         Err(PaymentError::Invoice("payment pending")) => {},
 864                         Err(_) => panic!("unexpected error"),
 865                         Ok(_) => panic!("expected invoice error"),
 866                 }
 867
 868                 // Can repay an invoice once cleared from cache.
 869                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 870                 invoice_payer.remove_cached_payment(&payment_hash);
 871                 assert!(invoice_payer.pay_invoice(&invoice).is_ok());
 872
 873                 // Cannot retry paying an invoice if cleared from cache.
 874                 invoice_payer.remove_cached_payment(&payment_hash);
 875                 let event = Event::PaymentPathFailed {
 876                         payment_id,
 877                         payment_hash,
 878                         network_update: None,
 879                         rejected_by_dest: false,
 880                         all_paths_failed: false,
 881                         path: vec![],
 882                         short_channel_id: None,
 883                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 884                 };
 885                 invoice_payer.handle_event(&event);
 886                 assert_eq!(*event_handled.borrow(), true);
 887         }
 888
 889         #[test]
 890         fn fails_paying_invoice_with_routing_errors() {
 891                 let payer = TestPayer::new();
 892                 let router = FailingRouter {};
 893                 let scorer = RefCell::new(TestScorer::new());
 894                 let logger = TestLogger::new();
 895                 let invoice_payer =
 896                         InvoicePayer::new(&payer, router, &scorer, &logger, |_: &_| {}, RetryAttempts(0));
 897
 898                 let payment_preimage = PaymentPreimage([1; 32]);
 899                 let invoice = invoice(payment_preimage);
 900                 match invoice_payer.pay_invoice(&invoice) {
 901                         Err(PaymentError::Routing(_)) => {},
 902                         Err(_) => panic!("unexpected error"),
 903                         Ok(_) => panic!("expected routing error"),
 904                 }
 905         }
 906
 907         #[test]
 908         fn fails_paying_invoice_with_sending_errors() {
 909                 let payer = TestPayer::new().fails_on_attempt(1);
 910                 let router = TestRouter {};
 911                 let scorer = RefCell::new(TestScorer::new());
 912                 let logger = TestLogger::new();
 913                 let invoice_payer =
 914                         InvoicePayer::new(&payer, router, &scorer, &logger, |_: &_| {}, RetryAttempts(0));
 915
 916                 let payment_preimage = PaymentPreimage([1; 32]);
 917                 let invoice = invoice(payment_preimage);
 918                 match invoice_payer.pay_invoice(&invoice) {
 919                         Err(PaymentError::Sending(_)) => {},
 920                         Err(_) => panic!("unexpected error"),
 921                         Ok(_) => panic!("expected sending error"),
 922                 }
 923         }
 924
 925         #[test]
 926         fn pays_zero_value_invoice_using_amount() {
 927                 let event_handled = core::cell::RefCell::new(false);
 928                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 929
 930                 let payment_preimage = PaymentPreimage([1; 32]);
 931                 let invoice = zero_value_invoice(payment_preimage);
 932                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 933                 let final_value_msat = 100;
 934
 935                 let payer = TestPayer::new().expect_value_msat(final_value_msat);
 936                 let router = TestRouter {};
 937                 let scorer = RefCell::new(TestScorer::new());
 938                 let logger = TestLogger::new();
 939                 let invoice_payer =
 940                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(0));
 941
 942                 let payment_id =
 943                         Some(invoice_payer.pay_zero_value_invoice(&invoice, final_value_msat).unwrap());
 944                 assert_eq!(*payer.attempts.borrow(), 1);
 945
 946                 invoice_payer.handle_event(&Event::PaymentSent {
 947                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
 948                 });
 949                 assert_eq!(*event_handled.borrow(), true);
 950                 assert_eq!(*payer.attempts.borrow(), 1);
 951         }
 952
 953         #[test]
 954         fn fails_paying_zero_value_invoice_with_amount() {
 955                 let event_handled = core::cell::RefCell::new(false);
 956                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 957
 958                 let payer = TestPayer::new();
 959                 let router = TestRouter {};
 960                 let scorer = RefCell::new(TestScorer::new());
 961                 let logger = TestLogger::new();
 962                 let invoice_payer =
 963                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(0));
 964
 965                 let payment_preimage = PaymentPreimage([1; 32]);
 966                 let invoice = invoice(payment_preimage);
 967
 968                 // Cannot repay an invoice pending payment.
 969                 match invoice_payer.pay_zero_value_invoice(&invoice, 100) {
 970                         Err(PaymentError::Invoice("amount unexpected")) => {},
 971                         Err(_) => panic!("unexpected error"),
 972                         Ok(_) => panic!("expected invoice error"),
 973                 }
 974         }
 975
 976         #[test]
 977         fn scores_failed_channel() {
 978                 let event_handled = core::cell::RefCell::new(false);
 979                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 980
 981                 let payment_preimage = PaymentPreimage([1; 32]);
 982                 let invoice = invoice(payment_preimage);
 983                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 984                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 985                 let path = TestRouter::path_for_value(final_value_msat);
 986                 let short_channel_id = Some(path[0].short_channel_id);
 987
 988                 // Expect that scorer is given short_channel_id upon handling the event.
 989                 let payer = TestPayer::new();
 990                 let router = TestRouter {};
 991                 let scorer = RefCell::new(TestScorer::new().expect_channel_failure(short_channel_id.unwrap()));
 992                 let logger = TestLogger::new();
 993                 let invoice_payer =
 994                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 995
 996                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 997                 let event = Event::PaymentPathFailed {
 998                         payment_id,
 999                         payment_hash,
1000                         network_update: None,
1001                         rejected_by_dest: false,
1002                         all_paths_failed: false,
1003                         path,
1004                         short_channel_id,
1005                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
1006                 };
1007                 invoice_payer.handle_event(&event);
1008         }
1009
1010         struct TestRouter;
1011
1012         impl TestRouter {
1013                 fn route_for_value(final_value_msat: u64) -> Route {
1014                         Route {
1015                                 paths: vec![
1016                                         vec![RouteHop {
1017                                                 pubkey: PublicKey::from_slice(&hex::decode("02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619").unwrap()[..]).unwrap(),
1018                                                 channel_features: ChannelFeatures::empty(),
1019                                                 node_features: NodeFeatures::empty(),
1020                                                 short_channel_id: 0, fee_msat: final_value_msat / 2, cltv_expiry_delta: 144
1021                                         }],
1022                                         vec![RouteHop {
1023                                                 pubkey: PublicKey::from_slice(&hex::decode("0324653eac434488002cc06bbfb7f10fe18991e35f9fe4302dbea6d2353dc0ab1c").unwrap()[..]).unwrap(),
1024                                                 channel_features: ChannelFeatures::empty(),
1025                                                 node_features: NodeFeatures::empty(),
1026                                                 short_channel_id: 1, fee_msat: final_value_msat / 2, cltv_expiry_delta: 144
1027                                         }],
1028                                 ],
1029                                 payee: None,
1030                         }
1031                 }
1032
1033                 fn path_for_value(final_value_msat: u64) -> Vec<RouteHop> {
1034                         TestRouter::route_for_value(final_value_msat).paths[0].clone()
1035                 }
1036
1037                 fn retry_for_invoice(invoice: &Invoice) -> RouteParameters {
1038                         let mut payee = Payee::from_node_id(invoice.recover_payee_pub_key())
1039                                 .with_expiry_time(expiry_time_from_unix_epoch(invoice).as_secs())
1040                                 .with_route_hints(invoice.route_hints());
1041                         if let Some(features) = invoice.features() {
1042                                 payee = payee.with_features(features.clone());
1043                         }
1044                         let final_value_msat = invoice.amount_milli_satoshis().unwrap() / 2;
1045                         RouteParameters {
1046                                 payee,
1047                                 final_value_msat,
1048                                 final_cltv_expiry_delta: invoice.min_final_cltv_expiry() as u32,
1049                         }
1050                 }
1051         }
1052
1053         impl<S: routing::Score> Router<S> for TestRouter {
1054                 fn find_route(
1055                         &self,
1056                         _payer: &PublicKey,
1057                         params: &RouteParameters,
1058                         _first_hops: Option<&[&ChannelDetails]>,
1059                         _scorer: &S,
1060                 ) -> Result<Route, LightningError> {
1061                         Ok(Route {
1062                                 payee: Some(params.payee.clone()), ..Self::route_for_value(params.final_value_msat)
1063                         })
1064                 }
1065         }
1066
1067         struct FailingRouter;
1068
1069         impl<S: routing::Score> Router<S> for FailingRouter {
1070                 fn find_route(
1071                         &self,
1072                         _payer: &PublicKey,
1073                         _params: &RouteParameters,
1074                         _first_hops: Option<&[&ChannelDetails]>,
1075                         _scorer: &S,
1076                 ) -> Result<Route, LightningError> {
1077                         Err(LightningError { err: String::new(), action: ErrorAction::IgnoreError })
1078                 }
1079         }
1080
1081         struct TestScorer {
1082                 expectations: VecDeque<u64>,
1083         }
1084
1085         impl TestScorer {
1086                 fn new() -> Self {
1087                         Self {
1088                                 expectations: VecDeque::new(),
1089                         }
1090                 }
1091
1092                 fn expect_channel_failure(mut self, short_channel_id: u64) -> Self {
1093                         self.expectations.push_back(short_channel_id);
1094                         self
1095                 }
1096         }
1097
1098         impl routing::Score for TestScorer {
1099                 fn channel_penalty_msat(
1100                         &self, _short_channel_id: u64, _source: &NodeId, _target: &NodeId
1101                 ) -> u64 { 0 }
1102
1103                 fn payment_path_failed(&mut self, _path: &[&RouteHop], short_channel_id: u64) {
1104                         if let Some(expected_short_channel_id) = self.expectations.pop_front() {
1105                                 assert_eq!(short_channel_id, expected_short_channel_id);
1106                         }
1107                 }
1108         }
1109
1110         impl Drop for TestScorer {
1111                 fn drop(&mut self) {
1112                         if std::thread::panicking() {
1113                                 return;
1114                         }
1115
1116                         if !self.expectations.is_empty() {
1117                                 panic!("Unsatisfied channel failure expectations: {:?}", self.expectations);
1118                         }
1119                 }
1120         }
1121
1122         struct TestPayer {
1123                 expectations: core::cell::RefCell<VecDeque<u64>>,
1124                 attempts: core::cell::RefCell<usize>,
1125                 failing_on_attempt: Option<usize>,
1126         }
1127
1128         impl TestPayer {
1129                 fn new() -> Self {
1130                         Self {
1131                                 expectations: core::cell::RefCell::new(VecDeque::new()),
1132                                 attempts: core::cell::RefCell::new(0),
1133                                 failing_on_attempt: None,
1134                         }
1135                 }
1136
1137                 fn expect_value_msat(self, value_msat: u64) -> Self {
1138                         self.expectations.borrow_mut().push_back(value_msat);
1139                         self
1140                 }
1141
1142                 fn fails_on_attempt(self, attempt: usize) -> Self {
1143                         Self {
1144                                 expectations: core::cell::RefCell::new(self.expectations.borrow().clone()),
1145                                 attempts: core::cell::RefCell::new(0),
1146                                 failing_on_attempt: Some(attempt),
1147                         }
1148                 }
1149
1150                 fn check_attempts(&self) -> bool {
1151                         let mut attempts = self.attempts.borrow_mut();
1152                         *attempts += 1;
1153                         match self.failing_on_attempt {
1154                                 None => true,
1155                                 Some(attempt) if attempt != *attempts => true,
1156                                 Some(_) => false,
1157                         }
1158                 }
1159
1160                 fn check_value_msats(&self, route: &Route) {
1161                         let expected_value_msats = self.expectations.borrow_mut().pop_front();
1162                         if let Some(expected_value_msats) = expected_value_msats {
1163                                 let actual_value_msats = route.get_total_amount();
1164                                 assert_eq!(actual_value_msats, expected_value_msats);
1165                         }
1166                 }
1167         }
1168
1169         impl Drop for TestPayer {
1170                 fn drop(&mut self) {
1171                         if std::thread::panicking() {
1172                                 return;
1173                         }
1174
1175                         if !self.expectations.borrow().is_empty() {
1176                                 panic!("Unsatisfied payment expectations: {:?}", self.expectations.borrow());
1177                         }
1178                 }
1179         }
1180
1181         impl Payer for TestPayer {
1182                 fn node_id(&self) -> PublicKey {
1183                         let secp_ctx = Secp256k1::new();
1184                         PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap())
1185                 }
1186
1187                 fn first_hops(&self) -> Vec<ChannelDetails> {
1188                         Vec::new()
1189                 }
1190
1191                 fn send_payment(
1192                         &self,
1193                         route: &Route,
1194                         _payment_hash: PaymentHash,
1195                         _payment_secret: &Option<PaymentSecret>
1196                 ) -> Result<PaymentId, PaymentSendFailure> {
1197                         if self.check_attempts() {
1198                                 self.check_value_msats(route);
1199                                 Ok(PaymentId([1; 32]))
1200                         } else {
1201                                 Err(PaymentSendFailure::ParameterError(APIError::MonitorUpdateFailed))
1202                         }
1203                 }
1204
1205                 fn retry_payment(
1206                         &self, route: &Route, _payment_id: PaymentId
1207                 ) -> Result<(), PaymentSendFailure> {
1208                         if self.check_attempts() {
1209                                 self.check_value_msats(route);
1210                                 Ok(())
1211                         } else {
1212                                 Err(PaymentSendFailure::ParameterError(APIError::MonitorUpdateFailed))
1213                         }
1214                 }
1215         }
1216
1217         // *** Full Featured Functional Tests with a Real ChannelManager ***
1218         struct ManualRouter(RefCell<VecDeque<Result<Route, LightningError>>>);
1219
1220         impl<S: routing::Score> Router<S> for ManualRouter {
1221                 fn find_route(&self, _payer: &PublicKey, _params: &RouteParameters, _first_hops: Option<&[&ChannelDetails]>, _scorer: &S)
1222                 -> Result<Route, LightningError> {
1223                         self.0.borrow_mut().pop_front().unwrap()
1224                 }
1225         }
1226         impl ManualRouter {
1227                 fn expect_find_route(&self, result: Result<Route, LightningError>) {
1228                         self.0.borrow_mut().push_back(result);
1229                 }
1230         }
1231         impl Drop for ManualRouter {
1232                 fn drop(&mut self) {
1233                         if std::thread::panicking() {
1234                                 return;
1235                         }
1236                         assert!(self.0.borrow_mut().is_empty());
1237                 }
1238         }
1239
1240         #[test]
1241         fn retry_multi_path_single_failed_payment() {
1242                 // Tests that we can/will retry after a single path of an MPP payment failed immediately
1243                 let chanmon_cfgs = create_chanmon_cfgs(2);
1244                 let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
1245                 let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None, None]);
1246                 let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
1247
1248                 create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0, InitFeatures::known(), InitFeatures::known());
1249                 create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0, InitFeatures::known(), InitFeatures::known());
1250                 let chans = nodes[0].node.list_usable_channels();
1251                 let mut route = Route {
1252                         paths: vec![
1253                                 vec![RouteHop {
1254                                         pubkey: nodes[1].node.get_our_node_id(),
1255                                         node_features: NodeFeatures::known(),
1256                                         short_channel_id: chans[0].short_channel_id.unwrap(),
1257                                         channel_features: ChannelFeatures::known(),
1258                                         fee_msat: 10_000,
1259                                         cltv_expiry_delta: 100,
1260                                 }],
1261                                 vec![RouteHop {
1262                                         pubkey: nodes[1].node.get_our_node_id(),
1263                                         node_features: NodeFeatures::known(),
1264                                         short_channel_id: chans[1].short_channel_id.unwrap(),
1265                                         channel_features: ChannelFeatures::known(),
1266                                         fee_msat: 100_000_001, // Our default max-HTLC-value is 10% of the channel value, which this is one more than
1267                                         cltv_expiry_delta: 100,
1268                                 }],
1269                         ],
1270                         payee: Some(Payee::from_node_id(nodes[1].node.get_our_node_id())),
1271                 };
1272                 let router = ManualRouter(RefCell::new(VecDeque::new()));
1273                 router.expect_find_route(Ok(route.clone()));
1274                 // On retry, split the payment across both channels.
1275                 route.paths[0][0].fee_msat = 50_000_001;
1276                 route.paths[1][0].fee_msat = 50_000_000;
1277                 router.expect_find_route(Ok(route.clone()));
1278
1279                 let event_handler = |_: &_| { panic!(); };
1280                 let scorer = RefCell::new(TestScorer::new());
1281                 let invoice_payer = InvoicePayer::new(nodes[0].node, router, &scorer, nodes[0].logger, event_handler, RetryAttempts(1));
1282
1283                 assert!(invoice_payer.pay_invoice(&create_invoice_from_channelmanager(
1284                         &nodes[1].node, nodes[1].keys_manager, Currency::Bitcoin, Some(100_010_000), "Invoice".to_string()).unwrap())
1285                         .is_ok());
1286                 let htlc_msgs = nodes[0].node.get_and_clear_pending_msg_events();
1287                 assert_eq!(htlc_msgs.len(), 2);
1288                 check_added_monitors!(nodes[0], 2);
1289         }
1290
1291         #[test]
1292         fn immediate_retry_on_failure() {
1293                 // Tests that we can/will retry immediately after a failure
1294                 let chanmon_cfgs = create_chanmon_cfgs(2);
1295                 let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
1296                 let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None, None]);
1297                 let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
1298
1299                 create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0, InitFeatures::known(), InitFeatures::known());
1300                 create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0, InitFeatures::known(), InitFeatures::known());
1301                 let chans = nodes[0].node.list_usable_channels();
1302                 let mut route = Route {
1303                         paths: vec![
1304                                 vec![RouteHop {
1305                                         pubkey: nodes[1].node.get_our_node_id(),
1306                                         node_features: NodeFeatures::known(),
1307                                         short_channel_id: chans[0].short_channel_id.unwrap(),
1308                                         channel_features: ChannelFeatures::known(),
1309                                         fee_msat: 100_000_001, // Our default max-HTLC-value is 10% of the channel value, which this is one more than
1310                                         cltv_expiry_delta: 100,
1311                                 }],
1312                         ],
1313                         payee: Some(Payee::from_node_id(nodes[1].node.get_our_node_id())),
1314                 };
1315                 let router = ManualRouter(RefCell::new(VecDeque::new()));
1316                 router.expect_find_route(Ok(route.clone()));
1317                 // On retry, split the payment across both channels.
1318                 route.paths.push(route.paths[0].clone());
1319                 route.paths[0][0].short_channel_id = chans[1].short_channel_id.unwrap();
1320                 route.paths[0][0].fee_msat = 50_000_000;
1321                 route.paths[1][0].fee_msat = 50_000_001;
1322                 router.expect_find_route(Ok(route.clone()));
1323
1324                 let event_handler = |_: &_| { panic!(); };
1325                 let scorer = RefCell::new(TestScorer::new());
1326                 let invoice_payer = InvoicePayer::new(nodes[0].node, router, &scorer, nodes[0].logger, event_handler, RetryAttempts(1));
1327
1328                 assert!(invoice_payer.pay_invoice(&create_invoice_from_channelmanager(
1329                         &nodes[1].node, nodes[1].keys_manager, Currency::Bitcoin, Some(100_010_000), "Invoice".to_string()).unwrap())
1330                         .is_ok());
1331                 let htlc_msgs = nodes[0].node.get_and_clear_pending_msg_events();
1332                 assert_eq!(htlc_msgs.len(), 2);
1333                 check_added_monitors!(nodes[0], 2);
1334         }
1335 }