_ 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 and sending spontaneous payments.
  11 //!
  12 //! Defines an [`InvoicePayer`] utility for sending payments, 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`], when
  16 //! applicable.
  17 //!
  18 //! [`InvoicePayer`] is parameterized by a [`LockableScore`], which it uses for scoring failed and
  19 //! successful payment paths upon receiving [`Event::PaymentPathFailed`] and
  20 //! [`Event::PaymentPathSuccessful`] events, respectively.
  21 //!
  22 //! [`InvoicePayer`] is capable of retrying failed payments. It accomplishes this by implementing
  23 //! [`EventHandler`] which decorates a user-provided handler. It will intercept any
  24 //! [`Event::PaymentPathFailed`] events and retry the failed paths for a fixed number of total
  25 //! attempts or until retry is no longer possible. In such a situation, [`InvoicePayer`] will pass
  26 //! along the events to the user-provided handler.
  27 //!
  28 //! # Example
  29 //!
  30 //! ```
  31 //! # extern crate lightning;
  32 //! # extern crate lightning_invoice;
  33 //! # extern crate secp256k1;
  34 //! #
  35 //! # use lightning::ln::{PaymentHash, PaymentPreimage, PaymentSecret};
  36 //! # use lightning::ln::channelmanager::{ChannelDetails, PaymentId, PaymentSendFailure};
  37 //! # use lightning::ln::msgs::LightningError;
  38 //! # use lightning::routing::scoring::Score;
  39 //! # use lightning::routing::network_graph::NodeId;
  40 //! # use lightning::routing::router::{Route, RouteHop, RouteParameters};
  41 //! # use lightning::util::events::{Event, EventHandler, EventsProvider};
  42 //! # use lightning::util::logger::{Logger, Record};
  43 //! # use lightning::util::ser::{Writeable, Writer};
  44 //! # use lightning_invoice::Invoice;
  45 //! # use lightning_invoice::payment::{InvoicePayer, Payer, RetryAttempts, Router};
  46 //! # use secp256k1::key::PublicKey;
  47 //! # use std::cell::RefCell;
  48 //! # use std::ops::Deref;
  49 //! #
  50 //! # struct FakeEventProvider {}
  51 //! # impl EventsProvider for FakeEventProvider {
  52 //! #     fn process_pending_events<H: Deref>(&self, handler: H) where H::Target: EventHandler {}
  53 //! # }
  54 //! #
  55 //! # struct FakePayer {}
  56 //! # impl Payer for FakePayer {
  57 //! #     fn node_id(&self) -> PublicKey { unimplemented!() }
  58 //! #     fn first_hops(&self) -> Vec<ChannelDetails> { unimplemented!() }
  59 //! #     fn send_payment(
  60 //! #         &self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>
  61 //! #     ) -> Result<PaymentId, PaymentSendFailure> { unimplemented!() }
  62 //! #     fn send_spontaneous_payment(
  63 //! #         &self, route: &Route, payment_preimage: PaymentPreimage
  64 //! #     ) -> Result<PaymentId, PaymentSendFailure> { unimplemented!() }
  65 //! #     fn retry_payment(
  66 //! #         &self, route: &Route, payment_id: PaymentId
  67 //! #     ) -> Result<(), PaymentSendFailure> { unimplemented!() }
  68 //! #     fn abandon_payment(&self, payment_id: PaymentId) { unimplemented!() }
  69 //! # }
  70 //! #
  71 //! # struct FakeRouter {}
  72 //! # impl<S: Score> Router<S> for FakeRouter {
  73 //! #     fn find_route(
  74 //! #         &self, payer: &PublicKey, params: &RouteParameters, payment_hash: &PaymentHash,
  75 //! #         first_hops: Option<&[&ChannelDetails]>, scorer: &S
  76 //! #     ) -> Result<Route, LightningError> { unimplemented!() }
  77 //! # }
  78 //! #
  79 //! # struct FakeScorer {}
  80 //! # impl Writeable for FakeScorer {
  81 //! #     fn write<W: Writer>(&self, w: &mut W) -> Result<(), std::io::Error> { unimplemented!(); }
  82 //! # }
  83 //! # impl Score for FakeScorer {
  84 //! #     fn channel_penalty_msat(
  85 //! #         &self, _short_channel_id: u64, _send_amt: u64, _chan_amt: Option<u64>, _source: &NodeId, _target: &NodeId
  86 //! #     ) -> u64 { 0 }
  87 //! #     fn payment_path_failed(&mut self, _path: &[&RouteHop], _short_channel_id: u64) {}
  88 //! #     fn payment_path_successful(&mut self, _path: &[&RouteHop]) {}
  89 //! # }
  90 //! #
  91 //! # struct FakeLogger {}
  92 //! # impl Logger for FakeLogger {
  93 //! #     fn log(&self, record: &Record) { unimplemented!() }
  94 //! # }
  95 //! #
  96 //! # fn main() {
  97 //! let event_handler = |event: &Event| {
  98 //!     match event {
  99 //!         Event::PaymentPathFailed { .. } => println!("payment failed after retries"),
 100 //!         Event::PaymentSent { .. } => println!("payment successful"),
 101 //!         _ => {},
 102 //!     }
 103 //! };
 104 //! # let payer = FakePayer {};
 105 //! # let router = FakeRouter {};
 106 //! # let scorer = RefCell::new(FakeScorer {});
 107 //! # let logger = FakeLogger {};
 108 //! let invoice_payer = InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 109 //!
 110 //! let invoice = "...";
 111 //! if let Ok(invoice) = invoice.parse::<Invoice>() {
 112 //!     invoice_payer.pay_invoice(&invoice).unwrap();
 113 //!
 114 //! # let event_provider = FakeEventProvider {};
 115 //!     loop {
 116 //!         event_provider.process_pending_events(&invoice_payer);
 117 //!     }
 118 //! }
 119 //! # }
 120 //! ```
 121 //!
 122 //! # Note
 123 //!
 124 //! The [`Route`] is computed before each payment attempt. Any updates affecting path finding such
 125 //! as updates to the network graph or changes to channel scores should be applied prior to
 126 //! retries, typically by way of composing [`EventHandler`]s accordingly.
 127
 128 use crate::Invoice;
 129
 130 use bitcoin_hashes::Hash;
 131 use bitcoin_hashes::sha256::Hash as Sha256;
 132
 133 use lightning::ln::{PaymentHash, PaymentPreimage, PaymentSecret};
 134 use lightning::ln::channelmanager::{ChannelDetails, PaymentId, PaymentSendFailure};
 135 use lightning::ln::msgs::LightningError;
 136 use lightning::routing::scoring::{LockableScore, Score};
 137 use lightning::routing::router::{Payee, Route, RouteParameters};
 138 use lightning::util::events::{Event, EventHandler};
 139 use lightning::util::logger::Logger;
 140
 141 use secp256k1::key::PublicKey;
 142
 143 use std::collections::hash_map::{self, HashMap};
 144 use std::ops::Deref;
 145 use std::sync::Mutex;
 146 use std::time::{Duration, SystemTime};
 147
 148 /// A utility for paying [`Invoice`]s and sending spontaneous payments.
 149 ///
 150 /// See [module-level documentation] for details.
 151 ///
 152 /// [module-level documentation]: crate::payment
 153 pub struct InvoicePayer<P: Deref, R, S: Deref, L: Deref, E>
 154 where
 155         P::Target: Payer,
 156         R: for <'a> Router<<<S as Deref>::Target as LockableScore<'a>>::Locked>,
 157         S::Target: for <'a> LockableScore<'a>,
 158         L::Target: Logger,
 159         E: EventHandler,
 160 {
 161         payer: P,
 162         router: R,
 163         scorer: S,
 164         logger: L,
 165         event_handler: E,
 166         /// Caches the overall attempts at making a payment, which is updated prior to retrying.
 167         payment_cache: Mutex<HashMap<PaymentHash, usize>>,
 168         retry_attempts: RetryAttempts,
 169 }
 170
 171 /// A trait defining behavior of an [`Invoice`] payer.
 172 pub trait Payer {
 173         /// Returns the payer's node id.
 174         fn node_id(&self) -> PublicKey;
 175
 176         /// Returns the payer's channels.
 177         fn first_hops(&self) -> Vec<ChannelDetails>;
 178
 179         /// Sends a payment over the Lightning Network using the given [`Route`].
 180         fn send_payment(
 181                 &self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>
 182         ) -> Result<PaymentId, PaymentSendFailure>;
 183
 184         /// Sends a spontaneous payment over the Lightning Network using the given [`Route`].
 185         fn send_spontaneous_payment(
 186                 &self, route: &Route, payment_preimage: PaymentPreimage
 187         ) -> Result<PaymentId, PaymentSendFailure>;
 188
 189         /// Retries a failed payment path for the [`PaymentId`] using the given [`Route`].
 190         fn retry_payment(&self, route: &Route, payment_id: PaymentId) -> Result<(), PaymentSendFailure>;
 191
 192         /// Signals that no further retries for the given payment will occur.
 193         fn abandon_payment(&self, payment_id: PaymentId);
 194 }
 195
 196 /// A trait defining behavior for routing an [`Invoice`] payment.
 197 pub trait Router<S: Score> {
 198         /// Finds a [`Route`] between `payer` and `payee` for a payment with the given values.
 199         fn find_route(
 200                 &self, payer: &PublicKey, params: &RouteParameters, payment_hash: &PaymentHash,
 201                 first_hops: Option<&[&ChannelDetails]>, scorer: &S
 202         ) -> Result<Route, LightningError>;
 203 }
 204
 205 /// Number of attempts to retry payment path failures for an [`Invoice`].
 206 ///
 207 /// Note that this is the number of *path* failures, not full payment retries. For multi-path
 208 /// payments, if this is less than the total number of paths, we will never even retry all of the
 209 /// payment's paths.
 210 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
 211 pub struct RetryAttempts(pub usize);
 212
 213 /// An error that may occur when making a payment.
 214 #[derive(Clone, Debug)]
 215 pub enum PaymentError {
 216         /// An error resulting from the provided [`Invoice`] or payment hash.
 217         Invoice(&'static str),
 218         /// An error occurring when finding a route.
 219         Routing(LightningError),
 220         /// An error occurring when sending a payment.
 221         Sending(PaymentSendFailure),
 222 }
 223
 224 impl<P: Deref, R, S: Deref, L: Deref, E> InvoicePayer<P, R, S, L, E>
 225 where
 226         P::Target: Payer,
 227         R: for <'a> Router<<<S as Deref>::Target as LockableScore<'a>>::Locked>,
 228         S::Target: for <'a> LockableScore<'a>,
 229         L::Target: Logger,
 230         E: EventHandler,
 231 {
 232         /// Creates an invoice payer that retries failed payment paths.
 233         ///
 234         /// Will forward any [`Event::PaymentPathFailed`] events to the decorated `event_handler` once
 235         /// `retry_attempts` has been exceeded for a given [`Invoice`].
 236         pub fn new(
 237                 payer: P, router: R, scorer: S, logger: L, event_handler: E, retry_attempts: RetryAttempts
 238         ) -> Self {
 239                 Self {
 240                         payer,
 241                         router,
 242                         scorer,
 243                         logger,
 244                         event_handler,
 245                         payment_cache: Mutex::new(HashMap::new()),
 246                         retry_attempts,
 247                 }
 248         }
 249
 250         /// Pays the given [`Invoice`], caching it for later use in case a retry is needed.
 251         ///
 252         /// You should ensure that the `invoice.payment_hash()` is unique and the same payment_hash has
 253         /// never been paid before. Because [`InvoicePayer`] is stateless no effort is made to do so
 254         /// for you.
 255         pub fn pay_invoice(&self, invoice: &Invoice) -> Result<PaymentId, PaymentError> {
 256                 if invoice.amount_milli_satoshis().is_none() {
 257                         Err(PaymentError::Invoice("amount missing"))
 258                 } else {
 259                         self.pay_invoice_using_amount(invoice, None)
 260                 }
 261         }
 262
 263         /// Pays the given zero-value [`Invoice`] using the given amount, caching it for later use in
 264         /// case a retry is needed.
 265         ///
 266         /// You should ensure that the `invoice.payment_hash()` is unique and the same payment_hash has
 267         /// never been paid before. Because [`InvoicePayer`] is stateless no effort is made to do so
 268         /// for you.
 269         pub fn pay_zero_value_invoice(
 270                 &self, invoice: &Invoice, amount_msats: u64
 271         ) -> Result<PaymentId, PaymentError> {
 272                 if invoice.amount_milli_satoshis().is_some() {
 273                         Err(PaymentError::Invoice("amount unexpected"))
 274                 } else {
 275                         self.pay_invoice_using_amount(invoice, Some(amount_msats))
 276                 }
 277         }
 278
 279         fn pay_invoice_using_amount(
 280                 &self, invoice: &Invoice, amount_msats: Option<u64>
 281         ) -> Result<PaymentId, PaymentError> {
 282                 debug_assert!(invoice.amount_milli_satoshis().is_some() ^ amount_msats.is_some());
 283
 284                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 285                 match self.payment_cache.lock().unwrap().entry(payment_hash) {
 286                         hash_map::Entry::Occupied(_) => return Err(PaymentError::Invoice("payment pending")),
 287                         hash_map::Entry::Vacant(entry) => entry.insert(0),
 288                 };
 289
 290                 let payment_secret = Some(invoice.payment_secret().clone());
 291                 let mut payee = Payee::from_node_id(invoice.recover_payee_pub_key())
 292                         .with_expiry_time(expiry_time_from_unix_epoch(&invoice).as_secs())
 293                         .with_route_hints(invoice.route_hints());
 294                 if let Some(features) = invoice.features() {
 295                         payee = payee.with_features(features.clone());
 296                 }
 297                 let params = RouteParameters {
 298                         payee,
 299                         final_value_msat: invoice.amount_milli_satoshis().or(amount_msats).unwrap(),
 300                         final_cltv_expiry_delta: invoice.min_final_cltv_expiry() as u32,
 301                 };
 302
 303                 let send_payment = |route: &Route| {
 304                         self.payer.send_payment(route, payment_hash, &payment_secret)
 305                 };
 306                 self.pay_internal(&params, payment_hash, send_payment)
 307                         .map_err(|e| { self.payment_cache.lock().unwrap().remove(&payment_hash); e })
 308         }
 309
 310         /// Pays `pubkey` an amount using the hash of the given preimage, caching it for later use in
 311         /// case a retry is needed.
 312         ///
 313         /// You should ensure that `payment_preimage` is unique and that its `payment_hash` has never
 314         /// been paid before. Because [`InvoicePayer`] is stateless no effort is made to do so for you.
 315         pub fn pay_pubkey(
 316                 &self, pubkey: PublicKey, payment_preimage: PaymentPreimage, amount_msats: u64,
 317                 final_cltv_expiry_delta: u32
 318         ) -> Result<PaymentId, PaymentError> {
 319                 let payment_hash = PaymentHash(Sha256::hash(&payment_preimage.0).into_inner());
 320                 match self.payment_cache.lock().unwrap().entry(payment_hash) {
 321                         hash_map::Entry::Occupied(_) => return Err(PaymentError::Invoice("payment pending")),
 322                         hash_map::Entry::Vacant(entry) => entry.insert(0),
 323                 };
 324
 325                 let params = RouteParameters {
 326                         payee: Payee::for_keysend(pubkey),
 327                         final_value_msat: amount_msats,
 328                         final_cltv_expiry_delta,
 329                 };
 330
 331                 let send_payment = |route: &Route| {
 332                         self.payer.send_spontaneous_payment(route, payment_preimage)
 333                 };
 334                 self.pay_internal(&params, payment_hash, send_payment)
 335                         .map_err(|e| { self.payment_cache.lock().unwrap().remove(&payment_hash); e })
 336         }
 337
 338         fn pay_internal<F: FnOnce(&Route) -> Result<PaymentId, PaymentSendFailure> + Copy>(
 339                 &self, params: &RouteParameters, payment_hash: PaymentHash, send_payment: F,
 340         ) -> Result<PaymentId, PaymentError> {
 341                 if has_expired(params) {
 342                         log_trace!(self.logger, "Invoice expired prior to send for payment {}", log_bytes!(payment_hash.0));
 343                         return Err(PaymentError::Invoice("Invoice expired prior to send"));
 344                 }
 345
 346                 let payer = self.payer.node_id();
 347                 let first_hops = self.payer.first_hops();
 348                 let route = self.router.find_route(
 349                         &payer, params, &payment_hash, Some(&first_hops.iter().collect::<Vec<_>>()),
 350                         &self.scorer.lock()
 351                 ).map_err(|e| PaymentError::Routing(e))?;
 352
 353                 match send_payment(&route) {
 354                         Ok(payment_id) => Ok(payment_id),
 355                         Err(e) => match e {
 356                                 PaymentSendFailure::ParameterError(_) => Err(e),
 357                                 PaymentSendFailure::PathParameterError(_) => Err(e),
 358                                 PaymentSendFailure::AllFailedRetrySafe(_) => {
 359                                         let mut payment_cache = self.payment_cache.lock().unwrap();
 360                                         let retry_count = payment_cache.get_mut(&payment_hash).unwrap();
 361                                         if *retry_count >= self.retry_attempts.0 {
 362                                                 Err(e)
 363                                         } else {
 364                                                 *retry_count += 1;
 365                                                 std::mem::drop(payment_cache);
 366                                                 Ok(self.pay_internal(params, payment_hash, send_payment)?)
 367                                         }
 368                                 },
 369                                 PaymentSendFailure::PartialFailure { failed_paths_retry, payment_id, .. } => {
 370                                         if let Some(retry_data) = failed_paths_retry {
 371                                                 // Some paths were sent, even if we failed to send the full MPP value our
 372                                                 // recipient may misbehave and claim the funds, at which point we have to
 373                                                 // consider the payment sent, so return `Ok()` here, ignoring any retry
 374                                                 // errors.
 375                                                 let _ = self.retry_payment(payment_id, payment_hash, &retry_data);
 376                                                 Ok(payment_id)
 377                                         } else {
 378                                                 // This may happen if we send a payment and some paths fail, but
 379                                                 // only due to a temporary monitor failure or the like, implying
 380                                                 // they're really in-flight, but we haven't sent the initial
 381                                                 // HTLC-Add messages yet.
 382                                                 Ok(payment_id)
 383                                         }
 384                                 },
 385                         },
 386                 }.map_err(|e| PaymentError::Sending(e))
 387         }
 388
 389         fn retry_payment(
 390                 &self, payment_id: PaymentId, payment_hash: PaymentHash, params: &RouteParameters
 391         ) -> Result<(), ()> {
 392                 let max_payment_attempts = self.retry_attempts.0 + 1;
 393                 let attempts = *self.payment_cache.lock().unwrap()
 394                         .entry(payment_hash)
 395                         .and_modify(|attempts| *attempts += 1)
 396                         .or_insert(1);
 397
 398                 if attempts >= max_payment_attempts {
 399                         log_trace!(self.logger, "Payment {} exceeded maximum attempts; not retrying (attempts: {})", log_bytes!(payment_hash.0), attempts);
 400                         return Err(());
 401                 }
 402
 403                 if has_expired(params) {
 404                         log_trace!(self.logger, "Invoice expired for payment {}; not retrying (attempts: {})", log_bytes!(payment_hash.0), attempts);
 405                         return Err(());
 406                 }
 407
 408                 let payer = self.payer.node_id();
 409                 let first_hops = self.payer.first_hops();
 410                 let route = self.router.find_route(
 411                         &payer, &params, &payment_hash, Some(&first_hops.iter().collect::<Vec<_>>()),
 412                         &self.scorer.lock()
 413                 );
 414                 if route.is_err() {
 415                         log_trace!(self.logger, "Failed to find a route for payment {}; not retrying (attempts: {})", log_bytes!(payment_hash.0), attempts);
 416                         return Err(());
 417                 }
 418
 419                 match self.payer.retry_payment(&route.unwrap(), payment_id) {
 420                         Ok(()) => Ok(()),
 421                         Err(PaymentSendFailure::ParameterError(_)) |
 422                         Err(PaymentSendFailure::PathParameterError(_)) => {
 423                                 log_trace!(self.logger, "Failed to retry for payment {} due to bogus route/payment data, not retrying.", log_bytes!(payment_hash.0));
 424                                 Err(())
 425                         },
 426                         Err(PaymentSendFailure::AllFailedRetrySafe(_)) => {
 427                                 self.retry_payment(payment_id, payment_hash, params)
 428                         },
 429                         Err(PaymentSendFailure::PartialFailure { failed_paths_retry, .. }) => {
 430                                 if let Some(retry) = failed_paths_retry {
 431                                         // Always return Ok for the same reason as noted in pay_internal.
 432                                         let _ = self.retry_payment(payment_id, payment_hash, &retry);
 433                                 }
 434                                 Ok(())
 435                         },
 436                 }
 437         }
 438
 439         /// Removes the payment cached by the given payment hash.
 440         ///
 441         /// Should be called once a payment has failed or succeeded if not using [`InvoicePayer`] as an
 442         /// [`EventHandler`]. Otherwise, calling this method is unnecessary.
 443         pub fn remove_cached_payment(&self, payment_hash: &PaymentHash) {
 444                 self.payment_cache.lock().unwrap().remove(payment_hash);
 445         }
 446 }
 447
 448 fn expiry_time_from_unix_epoch(invoice: &Invoice) -> Duration {
 449         invoice.timestamp().duration_since(SystemTime::UNIX_EPOCH).unwrap() + invoice.expiry_time()
 450 }
 451
 452 fn has_expired(params: &RouteParameters) -> bool {
 453         if let Some(expiry_time) = params.payee.expiry_time {
 454                 Invoice::is_expired_from_epoch(&SystemTime::UNIX_EPOCH, Duration::from_secs(expiry_time))
 455         } else { false }
 456 }
 457
 458 impl<P: Deref, R, S: Deref, L: Deref, E> EventHandler for InvoicePayer<P, R, S, L, E>
 459 where
 460         P::Target: Payer,
 461         R: for <'a> Router<<<S as Deref>::Target as LockableScore<'a>>::Locked>,
 462         S::Target: for <'a> LockableScore<'a>,
 463         L::Target: Logger,
 464         E: EventHandler,
 465 {
 466         fn handle_event(&self, event: &Event) {
 467                 match event {
 468                         Event::PaymentPathFailed {
 469                                 payment_id, payment_hash, rejected_by_dest, path, short_channel_id, retry, ..
 470                         } => {
 471                                 if let Some(short_channel_id) = short_channel_id {
 472                                         let path = path.iter().collect::<Vec<_>>();
 473                                         self.scorer.lock().payment_path_failed(&path, *short_channel_id);
 474                                 }
 475
 476                                 if payment_id.is_none() {
 477                                         log_trace!(self.logger, "Payment {} has no id; not retrying", log_bytes!(payment_hash.0));
 478                                 } else if *rejected_by_dest {
 479                                         log_trace!(self.logger, "Payment {} rejected by destination; not retrying", log_bytes!(payment_hash.0));
 480                                         self.payer.abandon_payment(payment_id.unwrap());
 481                                 } else if retry.is_none() {
 482                                         log_trace!(self.logger, "Payment {} missing retry params; not retrying", log_bytes!(payment_hash.0));
 483                                         self.payer.abandon_payment(payment_id.unwrap());
 484                                 } else if self.retry_payment(payment_id.unwrap(), *payment_hash, retry.as_ref().unwrap()).is_ok() {
 485                                         // We retried at least somewhat, don't provide the PaymentPathFailed event to the user.
 486                                         return;
 487                                 } else {
 488                                         self.payer.abandon_payment(payment_id.unwrap());
 489                                 }
 490                         },
 491                         Event::PaymentFailed { payment_hash, .. } => {
 492                                 self.remove_cached_payment(&payment_hash);
 493                         },
 494                         Event::PaymentPathSuccessful { path, .. } => {
 495                                 let path = path.iter().collect::<Vec<_>>();
 496                                 self.scorer.lock().payment_path_successful(&path);
 497                         },
 498                         Event::PaymentSent { payment_hash, .. } => {
 499                                 let mut payment_cache = self.payment_cache.lock().unwrap();
 500                                 let attempts = payment_cache
 501                                         .remove(payment_hash)
 502                                         .map_or(1, |attempts| attempts + 1);
 503                                 log_trace!(self.logger, "Payment {} succeeded (attempts: {})", log_bytes!(payment_hash.0), attempts);
 504                         },
 505                         _ => {},
 506                 }
 507
 508                 // Delegate to the decorated event handler unless the payment is retried.
 509                 self.event_handler.handle_event(event)
 510         }
 511 }
 512
 513 #[cfg(test)]
 514 mod tests {
 515         use super::*;
 516         use crate::{DEFAULT_EXPIRY_TIME, InvoiceBuilder, Currency};
 517         use utils::create_invoice_from_channelmanager;
 518         use bitcoin_hashes::sha256::Hash as Sha256;
 519         use lightning::ln::PaymentPreimage;
 520         use lightning::ln::features::{ChannelFeatures, NodeFeatures, InitFeatures};
 521         use lightning::ln::functional_test_utils::*;
 522         use lightning::ln::msgs::{ChannelMessageHandler, ErrorAction, LightningError};
 523         use lightning::routing::network_graph::NodeId;
 524         use lightning::routing::router::{Payee, Route, RouteHop};
 525         use lightning::util::test_utils::TestLogger;
 526         use lightning::util::errors::APIError;
 527         use lightning::util::events::{Event, EventsProvider, MessageSendEvent, MessageSendEventsProvider};
 528         use secp256k1::{SecretKey, PublicKey, Secp256k1};
 529         use std::cell::RefCell;
 530         use std::collections::VecDeque;
 531         use std::time::{SystemTime, Duration};
 532
 533         fn invoice(payment_preimage: PaymentPreimage) -> Invoice {
 534                 let payment_hash = Sha256::hash(&payment_preimage.0);
 535                 let private_key = SecretKey::from_slice(&[42; 32]).unwrap();
 536                 InvoiceBuilder::new(Currency::Bitcoin)
 537                         .description("test".into())
 538                         .payment_hash(payment_hash)
 539                         .payment_secret(PaymentSecret([0; 32]))
 540                         .current_timestamp()
 541                         .min_final_cltv_expiry(144)
 542                         .amount_milli_satoshis(128)
 543                         .build_signed(|hash| {
 544                                 Secp256k1::new().sign_recoverable(hash, &private_key)
 545                         })
 546                         .unwrap()
 547         }
 548
 549         fn zero_value_invoice(payment_preimage: PaymentPreimage) -> Invoice {
 550                 let payment_hash = Sha256::hash(&payment_preimage.0);
 551                 let private_key = SecretKey::from_slice(&[42; 32]).unwrap();
 552                 InvoiceBuilder::new(Currency::Bitcoin)
 553                         .description("test".into())
 554                         .payment_hash(payment_hash)
 555                         .payment_secret(PaymentSecret([0; 32]))
 556                         .current_timestamp()
 557                         .min_final_cltv_expiry(144)
 558                         .build_signed(|hash| {
 559                                 Secp256k1::new().sign_recoverable(hash, &private_key)
 560                         })
 561                         .unwrap()
 562         }
 563
 564         fn expired_invoice(payment_preimage: PaymentPreimage) -> Invoice {
 565                 let payment_hash = Sha256::hash(&payment_preimage.0);
 566                 let private_key = SecretKey::from_slice(&[42; 32]).unwrap();
 567                 let timestamp = SystemTime::now()
 568                         .checked_sub(Duration::from_secs(DEFAULT_EXPIRY_TIME * 2))
 569                         .unwrap();
 570                 InvoiceBuilder::new(Currency::Bitcoin)
 571                         .description("test".into())
 572                         .payment_hash(payment_hash)
 573                         .payment_secret(PaymentSecret([0; 32]))
 574                         .timestamp(timestamp)
 575                         .min_final_cltv_expiry(144)
 576                         .amount_milli_satoshis(128)
 577                         .build_signed(|hash| {
 578                                 Secp256k1::new().sign_recoverable(hash, &private_key)
 579                         })
 580                         .unwrap()
 581         }
 582
 583         fn pubkey() -> PublicKey {
 584                 PublicKey::from_slice(&hex::decode("02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619").unwrap()[..]).unwrap()
 585         }
 586
 587         #[test]
 588         fn pays_invoice_on_first_attempt() {
 589                 let event_handled = core::cell::RefCell::new(false);
 590                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 591
 592                 let payment_preimage = PaymentPreimage([1; 32]);
 593                 let invoice = invoice(payment_preimage);
 594                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 595                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 596
 597                 let payer = TestPayer::new().expect_send(Amount::ForInvoice(final_value_msat));
 598                 let router = TestRouter {};
 599                 let scorer = RefCell::new(TestScorer::new());
 600                 let logger = TestLogger::new();
 601                 let invoice_payer =
 602                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(0));
 603
 604                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 605                 assert_eq!(*payer.attempts.borrow(), 1);
 606
 607                 invoice_payer.handle_event(&Event::PaymentSent {
 608                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
 609                 });
 610                 assert_eq!(*event_handled.borrow(), true);
 611                 assert_eq!(*payer.attempts.borrow(), 1);
 612         }
 613
 614         #[test]
 615         fn pays_invoice_on_retry() {
 616                 let event_handled = core::cell::RefCell::new(false);
 617                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 618
 619                 let payment_preimage = PaymentPreimage([1; 32]);
 620                 let invoice = invoice(payment_preimage);
 621                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 622                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 623
 624                 let payer = TestPayer::new()
 625                         .expect_send(Amount::ForInvoice(final_value_msat))
 626                         .expect_send(Amount::OnRetry(final_value_msat / 2));
 627                 let router = TestRouter {};
 628                 let scorer = RefCell::new(TestScorer::new());
 629                 let logger = TestLogger::new();
 630                 let invoice_payer =
 631                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 632
 633                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 634                 assert_eq!(*payer.attempts.borrow(), 1);
 635
 636                 let event = Event::PaymentPathFailed {
 637                         payment_id,
 638                         payment_hash,
 639                         network_update: None,
 640                         rejected_by_dest: false,
 641                         all_paths_failed: false,
 642                         path: TestRouter::path_for_value(final_value_msat),
 643                         short_channel_id: None,
 644                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 645                 };
 646                 invoice_payer.handle_event(&event);
 647                 assert_eq!(*event_handled.borrow(), false);
 648                 assert_eq!(*payer.attempts.borrow(), 2);
 649
 650                 invoice_payer.handle_event(&Event::PaymentSent {
 651                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
 652                 });
 653                 assert_eq!(*event_handled.borrow(), true);
 654                 assert_eq!(*payer.attempts.borrow(), 2);
 655         }
 656
 657         #[test]
 658         fn pays_invoice_on_partial_failure() {
 659                 let event_handler = |_: &_| { panic!() };
 660
 661                 let payment_preimage = PaymentPreimage([1; 32]);
 662                 let invoice = invoice(payment_preimage);
 663                 let retry = TestRouter::retry_for_invoice(&invoice);
 664                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 665
 666                 let payer = TestPayer::new()
 667                         .fails_with_partial_failure(retry.clone(), OnAttempt(1))
 668                         .fails_with_partial_failure(retry, OnAttempt(2))
 669                         .expect_send(Amount::ForInvoice(final_value_msat))
 670                         .expect_send(Amount::OnRetry(final_value_msat / 2))
 671                         .expect_send(Amount::OnRetry(final_value_msat / 2));
 672                 let router = TestRouter {};
 673                 let scorer = RefCell::new(TestScorer::new());
 674                 let logger = TestLogger::new();
 675                 let invoice_payer =
 676                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 677
 678                 assert!(invoice_payer.pay_invoice(&invoice).is_ok());
 679         }
 680
 681         #[test]
 682         fn retries_payment_path_for_unknown_payment() {
 683                 let event_handled = core::cell::RefCell::new(false);
 684                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 685
 686                 let payment_preimage = PaymentPreimage([1; 32]);
 687                 let invoice = invoice(payment_preimage);
 688                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 689                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 690
 691                 let payer = TestPayer::new()
 692                         .expect_send(Amount::OnRetry(final_value_msat / 2))
 693                         .expect_send(Amount::OnRetry(final_value_msat / 2));
 694                 let router = TestRouter {};
 695                 let scorer = RefCell::new(TestScorer::new());
 696                 let logger = TestLogger::new();
 697                 let invoice_payer =
 698                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 699
 700                 let payment_id = Some(PaymentId([1; 32]));
 701                 let event = Event::PaymentPathFailed {
 702                         payment_id,
 703                         payment_hash,
 704                         network_update: None,
 705                         rejected_by_dest: false,
 706                         all_paths_failed: false,
 707                         path: TestRouter::path_for_value(final_value_msat),
 708                         short_channel_id: None,
 709                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 710                 };
 711                 invoice_payer.handle_event(&event);
 712                 assert_eq!(*event_handled.borrow(), false);
 713                 assert_eq!(*payer.attempts.borrow(), 1);
 714
 715                 invoice_payer.handle_event(&event);
 716                 assert_eq!(*event_handled.borrow(), false);
 717                 assert_eq!(*payer.attempts.borrow(), 2);
 718
 719                 invoice_payer.handle_event(&Event::PaymentSent {
 720                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
 721                 });
 722                 assert_eq!(*event_handled.borrow(), true);
 723                 assert_eq!(*payer.attempts.borrow(), 2);
 724         }
 725
 726         #[test]
 727         fn fails_paying_invoice_after_max_retries() {
 728                 let event_handled = core::cell::RefCell::new(false);
 729                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 730
 731                 let payment_preimage = PaymentPreimage([1; 32]);
 732                 let invoice = invoice(payment_preimage);
 733                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 734
 735                 let payer = TestPayer::new()
 736                         .expect_send(Amount::ForInvoice(final_value_msat))
 737                         .expect_send(Amount::OnRetry(final_value_msat / 2))
 738                         .expect_send(Amount::OnRetry(final_value_msat / 2));
 739                 let router = TestRouter {};
 740                 let scorer = RefCell::new(TestScorer::new());
 741                 let logger = TestLogger::new();
 742                 let invoice_payer =
 743                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 744
 745                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 746                 assert_eq!(*payer.attempts.borrow(), 1);
 747
 748                 let event = Event::PaymentPathFailed {
 749                         payment_id,
 750                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 751                         network_update: None,
 752                         rejected_by_dest: false,
 753                         all_paths_failed: true,
 754                         path: TestRouter::path_for_value(final_value_msat),
 755                         short_channel_id: None,
 756                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 757                 };
 758                 invoice_payer.handle_event(&event);
 759                 assert_eq!(*event_handled.borrow(), false);
 760                 assert_eq!(*payer.attempts.borrow(), 2);
 761
 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: TestRouter::path_for_value(final_value_msat / 2),
 769                         short_channel_id: None,
 770                         retry: Some(RouteParameters {
 771                                 final_value_msat: final_value_msat / 2, ..TestRouter::retry_for_invoice(&invoice)
 772                         }),
 773                 };
 774                 invoice_payer.handle_event(&event);
 775                 assert_eq!(*event_handled.borrow(), false);
 776                 assert_eq!(*payer.attempts.borrow(), 3);
 777
 778                 invoice_payer.handle_event(&event);
 779                 assert_eq!(*event_handled.borrow(), true);
 780                 assert_eq!(*payer.attempts.borrow(), 3);
 781         }
 782
 783         #[test]
 784         fn fails_paying_invoice_with_missing_retry_params() {
 785                 let event_handled = core::cell::RefCell::new(false);
 786                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 787
 788                 let payment_preimage = PaymentPreimage([1; 32]);
 789                 let invoice = invoice(payment_preimage);
 790                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 791
 792                 let payer = TestPayer::new().expect_send(Amount::ForInvoice(final_value_msat));
 793                 let router = TestRouter {};
 794                 let scorer = RefCell::new(TestScorer::new());
 795                 let logger = TestLogger::new();
 796                 let invoice_payer =
 797                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 798
 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: false,
 807                         all_paths_failed: false,
 808                         path: vec![],
 809                         short_channel_id: None,
 810                         retry: None,
 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_paying_invoice_after_expiration() {
 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(2));
 828
 829                 let payment_preimage = PaymentPreimage([1; 32]);
 830                 let invoice = expired_invoice(payment_preimage);
 831                 if let PaymentError::Invoice(msg) = invoice_payer.pay_invoice(&invoice).unwrap_err() {
 832                         assert_eq!(msg, "Invoice expired prior to send");
 833                 } else { panic!("Expected Invoice Error"); }
 834         }
 835
 836         #[test]
 837         fn fails_retrying_invoice_after_expiration() {
 838                 let event_handled = core::cell::RefCell::new(false);
 839                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 840
 841                 let payment_preimage = PaymentPreimage([1; 32]);
 842                 let invoice = invoice(payment_preimage);
 843                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 844
 845                 let payer = TestPayer::new().expect_send(Amount::ForInvoice(final_value_msat));
 846                 let router = TestRouter {};
 847                 let scorer = RefCell::new(TestScorer::new());
 848                 let logger = TestLogger::new();
 849                 let invoice_payer =
 850                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 851
 852                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 853                 assert_eq!(*payer.attempts.borrow(), 1);
 854
 855                 let mut retry_data = TestRouter::retry_for_invoice(&invoice);
 856                 retry_data.payee.expiry_time = Some(SystemTime::now()
 857                         .checked_sub(Duration::from_secs(2)).unwrap()
 858                         .duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs());
 859                 let event = Event::PaymentPathFailed {
 860                         payment_id,
 861                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 862                         network_update: None,
 863                         rejected_by_dest: false,
 864                         all_paths_failed: false,
 865                         path: vec![],
 866                         short_channel_id: None,
 867                         retry: Some(retry_data),
 868                 };
 869                 invoice_payer.handle_event(&event);
 870                 assert_eq!(*event_handled.borrow(), true);
 871                 assert_eq!(*payer.attempts.borrow(), 1);
 872         }
 873
 874         #[test]
 875         fn fails_paying_invoice_after_retry_error() {
 876                 let event_handled = core::cell::RefCell::new(false);
 877                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 878
 879                 let payment_preimage = PaymentPreimage([1; 32]);
 880                 let invoice = invoice(payment_preimage);
 881                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 882
 883                 let payer = TestPayer::new()
 884                         .fails_on_attempt(2)
 885                         .expect_send(Amount::ForInvoice(final_value_msat))
 886                         .expect_send(Amount::OnRetry(final_value_msat / 2));
 887                 let router = TestRouter {};
 888                 let scorer = RefCell::new(TestScorer::new());
 889                 let logger = TestLogger::new();
 890                 let invoice_payer =
 891                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 892
 893                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 894                 assert_eq!(*payer.attempts.borrow(), 1);
 895
 896                 let event = Event::PaymentPathFailed {
 897                         payment_id,
 898                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 899                         network_update: None,
 900                         rejected_by_dest: false,
 901                         all_paths_failed: false,
 902                         path: TestRouter::path_for_value(final_value_msat / 2),
 903                         short_channel_id: None,
 904                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 905                 };
 906                 invoice_payer.handle_event(&event);
 907                 assert_eq!(*event_handled.borrow(), true);
 908                 assert_eq!(*payer.attempts.borrow(), 2);
 909         }
 910
 911         #[test]
 912         fn fails_paying_invoice_after_rejected_by_payee() {
 913                 let event_handled = core::cell::RefCell::new(false);
 914                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 915
 916                 let payment_preimage = PaymentPreimage([1; 32]);
 917                 let invoice = invoice(payment_preimage);
 918                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 919
 920                 let payer = TestPayer::new().expect_send(Amount::ForInvoice(final_value_msat));
 921                 let router = TestRouter {};
 922                 let scorer = RefCell::new(TestScorer::new());
 923                 let logger = TestLogger::new();
 924                 let invoice_payer =
 925                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 926
 927                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 928                 assert_eq!(*payer.attempts.borrow(), 1);
 929
 930                 let event = Event::PaymentPathFailed {
 931                         payment_id,
 932                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 933                         network_update: None,
 934                         rejected_by_dest: true,
 935                         all_paths_failed: false,
 936                         path: vec![],
 937                         short_channel_id: None,
 938                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 939                 };
 940                 invoice_payer.handle_event(&event);
 941                 assert_eq!(*event_handled.borrow(), true);
 942                 assert_eq!(*payer.attempts.borrow(), 1);
 943         }
 944
 945         #[test]
 946         fn fails_repaying_invoice_with_pending_payment() {
 947                 let event_handled = core::cell::RefCell::new(false);
 948                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 949
 950                 let payment_preimage = PaymentPreimage([1; 32]);
 951                 let invoice = invoice(payment_preimage);
 952                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 953
 954                 let payer = TestPayer::new()
 955                         .expect_send(Amount::ForInvoice(final_value_msat))
 956                         .expect_send(Amount::ForInvoice(final_value_msat));
 957                 let router = TestRouter {};
 958                 let scorer = RefCell::new(TestScorer::new());
 959                 let logger = TestLogger::new();
 960                 let invoice_payer =
 961                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(0));
 962
 963                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 964
 965                 // Cannot repay an invoice pending payment.
 966                 match invoice_payer.pay_invoice(&invoice) {
 967                         Err(PaymentError::Invoice("payment pending")) => {},
 968                         Err(_) => panic!("unexpected error"),
 969                         Ok(_) => panic!("expected invoice error"),
 970                 }
 971
 972                 // Can repay an invoice once cleared from cache.
 973                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 974                 invoice_payer.remove_cached_payment(&payment_hash);
 975                 assert!(invoice_payer.pay_invoice(&invoice).is_ok());
 976
 977                 // Cannot retry paying an invoice if cleared from cache.
 978                 invoice_payer.remove_cached_payment(&payment_hash);
 979                 let event = Event::PaymentPathFailed {
 980                         payment_id,
 981                         payment_hash,
 982                         network_update: None,
 983                         rejected_by_dest: false,
 984                         all_paths_failed: false,
 985                         path: vec![],
 986                         short_channel_id: None,
 987                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 988                 };
 989                 invoice_payer.handle_event(&event);
 990                 assert_eq!(*event_handled.borrow(), true);
 991         }
 992
 993         #[test]
 994         fn fails_paying_invoice_with_routing_errors() {
 995                 let payer = TestPayer::new();
 996                 let router = FailingRouter {};
 997                 let scorer = RefCell::new(TestScorer::new());
 998                 let logger = TestLogger::new();
 999                 let invoice_payer =
1000                         InvoicePayer::new(&payer, router, &scorer, &logger, |_: &_| {}, RetryAttempts(0));
1001
1002                 let payment_preimage = PaymentPreimage([1; 32]);
1003                 let invoice = invoice(payment_preimage);
1004                 match invoice_payer.pay_invoice(&invoice) {
1005                         Err(PaymentError::Routing(_)) => {},
1006                         Err(_) => panic!("unexpected error"),
1007                         Ok(_) => panic!("expected routing error"),
1008                 }
1009         }
1010
1011         #[test]
1012         fn fails_paying_invoice_with_sending_errors() {
1013                 let payment_preimage = PaymentPreimage([1; 32]);
1014                 let invoice = invoice(payment_preimage);
1015                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
1016
1017                 let payer = TestPayer::new()
1018                         .fails_on_attempt(1)
1019                         .expect_send(Amount::ForInvoice(final_value_msat));
1020                 let router = TestRouter {};
1021                 let scorer = RefCell::new(TestScorer::new());
1022                 let logger = TestLogger::new();
1023                 let invoice_payer =
1024                         InvoicePayer::new(&payer, router, &scorer, &logger, |_: &_| {}, RetryAttempts(0));
1025
1026                 match invoice_payer.pay_invoice(&invoice) {
1027                         Err(PaymentError::Sending(_)) => {},
1028                         Err(_) => panic!("unexpected error"),
1029                         Ok(_) => panic!("expected sending error"),
1030                 }
1031         }
1032
1033         #[test]
1034         fn pays_zero_value_invoice_using_amount() {
1035                 let event_handled = core::cell::RefCell::new(false);
1036                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1037
1038                 let payment_preimage = PaymentPreimage([1; 32]);
1039                 let invoice = zero_value_invoice(payment_preimage);
1040                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
1041                 let final_value_msat = 100;
1042
1043                 let payer = TestPayer::new().expect_send(Amount::ForInvoice(final_value_msat));
1044                 let router = TestRouter {};
1045                 let scorer = RefCell::new(TestScorer::new());
1046                 let logger = TestLogger::new();
1047                 let invoice_payer =
1048                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(0));
1049
1050                 let payment_id =
1051                         Some(invoice_payer.pay_zero_value_invoice(&invoice, final_value_msat).unwrap());
1052                 assert_eq!(*payer.attempts.borrow(), 1);
1053
1054                 invoice_payer.handle_event(&Event::PaymentSent {
1055                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
1056                 });
1057                 assert_eq!(*event_handled.borrow(), true);
1058                 assert_eq!(*payer.attempts.borrow(), 1);
1059         }
1060
1061         #[test]
1062         fn fails_paying_zero_value_invoice_with_amount() {
1063                 let event_handled = core::cell::RefCell::new(false);
1064                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1065
1066                 let payer = TestPayer::new();
1067                 let router = TestRouter {};
1068                 let scorer = RefCell::new(TestScorer::new());
1069                 let logger = TestLogger::new();
1070                 let invoice_payer =
1071                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(0));
1072
1073                 let payment_preimage = PaymentPreimage([1; 32]);
1074                 let invoice = invoice(payment_preimage);
1075
1076                 // Cannot repay an invoice pending payment.
1077                 match invoice_payer.pay_zero_value_invoice(&invoice, 100) {
1078                         Err(PaymentError::Invoice("amount unexpected")) => {},
1079                         Err(_) => panic!("unexpected error"),
1080                         Ok(_) => panic!("expected invoice error"),
1081                 }
1082         }
1083
1084         #[test]
1085         fn pays_pubkey_with_amount() {
1086                 let event_handled = core::cell::RefCell::new(false);
1087                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1088
1089                 let pubkey = pubkey();
1090                 let payment_preimage = PaymentPreimage([1; 32]);
1091                 let payment_hash = PaymentHash(Sha256::hash(&payment_preimage.0).into_inner());
1092                 let final_value_msat = 100;
1093                 let final_cltv_expiry_delta = 42;
1094
1095                 let payer = TestPayer::new()
1096                         .expect_send(Amount::Spontaneous(final_value_msat))
1097                         .expect_send(Amount::OnRetry(final_value_msat));
1098                 let router = TestRouter {};
1099                 let scorer = RefCell::new(TestScorer::new());
1100                 let logger = TestLogger::new();
1101                 let invoice_payer =
1102                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
1103
1104                 let payment_id = Some(invoice_payer.pay_pubkey(
1105                                 pubkey, payment_preimage, final_value_msat, final_cltv_expiry_delta
1106                         ).unwrap());
1107                 assert_eq!(*payer.attempts.borrow(), 1);
1108
1109                 let retry = RouteParameters {
1110                         payee: Payee::for_keysend(pubkey),
1111                         final_value_msat,
1112                         final_cltv_expiry_delta,
1113                 };
1114                 let event = Event::PaymentPathFailed {
1115                         payment_id,
1116                         payment_hash,
1117                         network_update: None,
1118                         rejected_by_dest: false,
1119                         all_paths_failed: false,
1120                         path: vec![],
1121                         short_channel_id: None,
1122                         retry: Some(retry),
1123                 };
1124                 invoice_payer.handle_event(&event);
1125                 assert_eq!(*event_handled.borrow(), false);
1126                 assert_eq!(*payer.attempts.borrow(), 2);
1127
1128                 invoice_payer.handle_event(&Event::PaymentSent {
1129                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
1130                 });
1131                 assert_eq!(*event_handled.borrow(), true);
1132                 assert_eq!(*payer.attempts.borrow(), 2);
1133         }
1134
1135         #[test]
1136         fn scores_failed_channel() {
1137                 let event_handled = core::cell::RefCell::new(false);
1138                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1139
1140                 let payment_preimage = PaymentPreimage([1; 32]);
1141                 let invoice = invoice(payment_preimage);
1142                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
1143                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
1144                 let path = TestRouter::path_for_value(final_value_msat);
1145                 let short_channel_id = Some(path[0].short_channel_id);
1146
1147                 // Expect that scorer is given short_channel_id upon handling the event.
1148                 let payer = TestPayer::new()
1149                         .expect_send(Amount::ForInvoice(final_value_msat))
1150                         .expect_send(Amount::OnRetry(final_value_msat / 2));
1151                 let router = TestRouter {};
1152                 let scorer = RefCell::new(TestScorer::new().expect(PaymentPath::Failure {
1153                         path: path.clone(), short_channel_id: path[0].short_channel_id,
1154                 }));
1155                 let logger = TestLogger::new();
1156                 let invoice_payer =
1157                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
1158
1159                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
1160                 let event = Event::PaymentPathFailed {
1161                         payment_id,
1162                         payment_hash,
1163                         network_update: None,
1164                         rejected_by_dest: false,
1165                         all_paths_failed: false,
1166                         path,
1167                         short_channel_id,
1168                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
1169                 };
1170                 invoice_payer.handle_event(&event);
1171         }
1172
1173         #[test]
1174         fn scores_successful_channels() {
1175                 let event_handled = core::cell::RefCell::new(false);
1176                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1177
1178                 let payment_preimage = PaymentPreimage([1; 32]);
1179                 let invoice = invoice(payment_preimage);
1180                 let payment_hash = Some(PaymentHash(invoice.payment_hash().clone().into_inner()));
1181                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
1182                 let route = TestRouter::route_for_value(final_value_msat);
1183
1184                 // Expect that scorer is given short_channel_id upon handling the event.
1185                 let payer = TestPayer::new().expect_send(Amount::ForInvoice(final_value_msat));
1186                 let router = TestRouter {};
1187                 let scorer = RefCell::new(TestScorer::new()
1188                         .expect(PaymentPath::Success { path: route.paths[0].clone() })
1189                         .expect(PaymentPath::Success { path: route.paths[1].clone() })
1190                 );
1191                 let logger = TestLogger::new();
1192                 let invoice_payer =
1193                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
1194
1195                 let payment_id = invoice_payer.pay_invoice(&invoice).unwrap();
1196                 let event = Event::PaymentPathSuccessful {
1197                         payment_id, payment_hash, path: route.paths[0].clone()
1198                 };
1199                 invoice_payer.handle_event(&event);
1200                 let event = Event::PaymentPathSuccessful {
1201                         payment_id, payment_hash, path: route.paths[1].clone()
1202                 };
1203                 invoice_payer.handle_event(&event);
1204         }
1205
1206         struct TestRouter;
1207
1208         impl TestRouter {
1209                 fn route_for_value(final_value_msat: u64) -> Route {
1210                         Route {
1211                                 paths: vec![
1212                                         vec![RouteHop {
1213                                                 pubkey: PublicKey::from_slice(&hex::decode("02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619").unwrap()[..]).unwrap(),
1214                                                 channel_features: ChannelFeatures::empty(),
1215                                                 node_features: NodeFeatures::empty(),
1216                                                 short_channel_id: 0, fee_msat: final_value_msat / 2, cltv_expiry_delta: 144
1217                                         }],
1218                                         vec![RouteHop {
1219                                                 pubkey: PublicKey::from_slice(&hex::decode("0324653eac434488002cc06bbfb7f10fe18991e35f9fe4302dbea6d2353dc0ab1c").unwrap()[..]).unwrap(),
1220                                                 channel_features: ChannelFeatures::empty(),
1221                                                 node_features: NodeFeatures::empty(),
1222                                                 short_channel_id: 1, fee_msat: final_value_msat / 2, cltv_expiry_delta: 144
1223                                         }],
1224                                 ],
1225                                 payee: None,
1226                         }
1227                 }
1228
1229                 fn path_for_value(final_value_msat: u64) -> Vec<RouteHop> {
1230                         TestRouter::route_for_value(final_value_msat).paths[0].clone()
1231                 }
1232
1233                 fn retry_for_invoice(invoice: &Invoice) -> RouteParameters {
1234                         let mut payee = Payee::from_node_id(invoice.recover_payee_pub_key())
1235                                 .with_expiry_time(expiry_time_from_unix_epoch(invoice).as_secs())
1236                                 .with_route_hints(invoice.route_hints());
1237                         if let Some(features) = invoice.features() {
1238                                 payee = payee.with_features(features.clone());
1239                         }
1240                         let final_value_msat = invoice.amount_milli_satoshis().unwrap() / 2;
1241                         RouteParameters {
1242                                 payee,
1243                                 final_value_msat,
1244                                 final_cltv_expiry_delta: invoice.min_final_cltv_expiry() as u32,
1245                         }
1246                 }
1247         }
1248
1249         impl<S: Score> Router<S> for TestRouter {
1250                 fn find_route(
1251                         &self, _payer: &PublicKey, params: &RouteParameters, _payment_hash: &PaymentHash,
1252                         _first_hops: Option<&[&ChannelDetails]>, _scorer: &S
1253                 ) -> Result<Route, LightningError> {
1254                         Ok(Route {
1255                                 payee: Some(params.payee.clone()), ..Self::route_for_value(params.final_value_msat)
1256                         })
1257                 }
1258         }
1259
1260         struct FailingRouter;
1261
1262         impl<S: Score> Router<S> for FailingRouter {
1263                 fn find_route(
1264                         &self, _payer: &PublicKey, _params: &RouteParameters, _payment_hash: &PaymentHash,
1265                         _first_hops: Option<&[&ChannelDetails]>, _scorer: &S
1266                 ) -> Result<Route, LightningError> {
1267                         Err(LightningError { err: String::new(), action: ErrorAction::IgnoreError })
1268                 }
1269         }
1270
1271         struct TestScorer {
1272                 expectations: Option<VecDeque<PaymentPath>>,
1273         }
1274
1275         #[derive(Debug)]
1276         enum PaymentPath {
1277                 Failure { path: Vec<RouteHop>, short_channel_id: u64 },
1278                 Success { path: Vec<RouteHop> },
1279         }
1280
1281         impl TestScorer {
1282                 fn new() -> Self {
1283                         Self {
1284                                 expectations: None,
1285                         }
1286                 }
1287
1288                 fn expect(mut self, expectation: PaymentPath) -> Self {
1289                         self.expectations.get_or_insert_with(|| VecDeque::new()).push_back(expectation);
1290                         self
1291                 }
1292         }
1293
1294         #[cfg(c_bindings)]
1295         impl lightning::util::ser::Writeable for TestScorer {
1296                 fn write<W: lightning::util::ser::Writer>(&self, _: &mut W) -> Result<(), std::io::Error> { unreachable!(); }
1297         }
1298
1299         impl Score for TestScorer {
1300                 fn channel_penalty_msat(
1301                         &self, _short_channel_id: u64, _send_amt: u64, _chan_amt: Option<u64>, _source: &NodeId, _target: &NodeId
1302                 ) -> u64 { 0 }
1303
1304                 fn payment_path_failed(&mut self, actual_path: &[&RouteHop], actual_short_channel_id: u64) {
1305                         if let Some(expectations) = &mut self.expectations {
1306                                 match expectations.pop_front() {
1307                                         Some(PaymentPath::Failure { path, short_channel_id }) => {
1308                                                 assert_eq!(actual_path, &path.iter().collect::<Vec<_>>()[..]);
1309                                                 assert_eq!(actual_short_channel_id, short_channel_id);
1310                                         },
1311                                         Some(PaymentPath::Success { path }) => {
1312                                                 panic!("Unexpected successful payment path: {:?}", path)
1313                                         },
1314                                         None => panic!("Unexpected payment_path_failed call: {:?}", actual_path),
1315                                 }
1316                         }
1317                 }
1318
1319                 fn payment_path_successful(&mut self, actual_path: &[&RouteHop]) {
1320                         if let Some(expectations) = &mut self.expectations {
1321                                 match expectations.pop_front() {
1322                                         Some(PaymentPath::Failure { path, .. }) => {
1323                                                 panic!("Unexpected payment path failure: {:?}", path)
1324                                         },
1325                                         Some(PaymentPath::Success { path }) => {
1326                                                 assert_eq!(actual_path, &path.iter().collect::<Vec<_>>()[..]);
1327                                         },
1328                                         None => panic!("Unexpected payment_path_successful call: {:?}", actual_path),
1329                                 }
1330                         }
1331                 }
1332         }
1333
1334         impl Drop for TestScorer {
1335                 fn drop(&mut self) {
1336                         if std::thread::panicking() {
1337                                 return;
1338                         }
1339
1340                         if let Some(expectations) = &self.expectations {
1341                                 if !expectations.is_empty() {
1342                                         panic!("Unsatisfied scorer expectations: {:?}", expectations);
1343                                 }
1344                         }
1345                 }
1346         }
1347
1348         struct TestPayer {
1349                 expectations: core::cell::RefCell<VecDeque<Amount>>,
1350                 attempts: core::cell::RefCell<usize>,
1351                 failing_on_attempt: core::cell::RefCell<HashMap<usize, PaymentSendFailure>>,
1352         }
1353
1354         #[derive(Clone, Debug, PartialEq, Eq)]
1355         enum Amount {
1356                 ForInvoice(u64),
1357                 Spontaneous(u64),
1358                 OnRetry(u64),
1359         }
1360
1361         struct OnAttempt(usize);
1362
1363         impl TestPayer {
1364                 fn new() -> Self {
1365                         Self {
1366                                 expectations: core::cell::RefCell::new(VecDeque::new()),
1367                                 attempts: core::cell::RefCell::new(0),
1368                                 failing_on_attempt: core::cell::RefCell::new(HashMap::new()),
1369                         }
1370                 }
1371
1372                 fn expect_send(self, value_msat: Amount) -> Self {
1373                         self.expectations.borrow_mut().push_back(value_msat);
1374                         self
1375                 }
1376
1377                 fn fails_on_attempt(self, attempt: usize) -> Self {
1378                         let failure = PaymentSendFailure::ParameterError(APIError::MonitorUpdateFailed);
1379                         self.fails_with(failure, OnAttempt(attempt))
1380                 }
1381
1382                 fn fails_with_partial_failure(self, retry: RouteParameters, attempt: OnAttempt) -> Self {
1383                         self.fails_with(PaymentSendFailure::PartialFailure {
1384                                 results: vec![],
1385                                 failed_paths_retry: Some(retry),
1386                                 payment_id: PaymentId([1; 32]),
1387                         }, attempt)
1388                 }
1389
1390                 fn fails_with(self, failure: PaymentSendFailure, attempt: OnAttempt) -> Self {
1391                         self.failing_on_attempt.borrow_mut().insert(attempt.0, failure);
1392                         self
1393                 }
1394
1395                 fn check_attempts(&self) -> Result<PaymentId, PaymentSendFailure> {
1396                         let mut attempts = self.attempts.borrow_mut();
1397                         *attempts += 1;
1398
1399                         match self.failing_on_attempt.borrow_mut().remove(&*attempts) {
1400                                 Some(failure) => Err(failure),
1401                                 None => Ok(PaymentId([1; 32])),
1402                         }
1403                 }
1404
1405                 fn check_value_msats(&self, actual_value_msats: Amount) {
1406                         let expected_value_msats = self.expectations.borrow_mut().pop_front();
1407                         if let Some(expected_value_msats) = expected_value_msats {
1408                                 assert_eq!(actual_value_msats, expected_value_msats);
1409                         } else {
1410                                 panic!("Unexpected amount: {:?}", actual_value_msats);
1411                         }
1412                 }
1413         }
1414
1415         impl Drop for TestPayer {
1416                 fn drop(&mut self) {
1417                         if std::thread::panicking() {
1418                                 return;
1419                         }
1420
1421                         if !self.expectations.borrow().is_empty() {
1422                                 panic!("Unsatisfied payment expectations: {:?}", self.expectations.borrow());
1423                         }
1424                 }
1425         }
1426
1427         impl Payer for TestPayer {
1428                 fn node_id(&self) -> PublicKey {
1429                         let secp_ctx = Secp256k1::new();
1430                         PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap())
1431                 }
1432
1433                 fn first_hops(&self) -> Vec<ChannelDetails> {
1434                         Vec::new()
1435                 }
1436
1437                 fn send_payment(
1438                         &self, route: &Route, _payment_hash: PaymentHash,
1439                         _payment_secret: &Option<PaymentSecret>
1440                 ) -> Result<PaymentId, PaymentSendFailure> {
1441                         self.check_value_msats(Amount::ForInvoice(route.get_total_amount()));
1442                         self.check_attempts()
1443                 }
1444
1445                 fn send_spontaneous_payment(
1446                         &self, route: &Route, _payment_preimage: PaymentPreimage,
1447                 ) -> Result<PaymentId, PaymentSendFailure> {
1448                         self.check_value_msats(Amount::Spontaneous(route.get_total_amount()));
1449                         self.check_attempts()
1450                 }
1451
1452                 fn retry_payment(
1453                         &self, route: &Route, _payment_id: PaymentId
1454                 ) -> Result<(), PaymentSendFailure> {
1455                         self.check_value_msats(Amount::OnRetry(route.get_total_amount()));
1456                         self.check_attempts().map(|_| ())
1457                 }
1458
1459                 fn abandon_payment(&self, _payment_id: PaymentId) { }
1460         }
1461
1462         // *** Full Featured Functional Tests with a Real ChannelManager ***
1463         struct ManualRouter(RefCell<VecDeque<Result<Route, LightningError>>>);
1464
1465         impl<S: Score> Router<S> for ManualRouter {
1466                 fn find_route(
1467                         &self, _payer: &PublicKey, _params: &RouteParameters, _payment_hash: &PaymentHash,
1468                         _first_hops: Option<&[&ChannelDetails]>, _scorer: &S
1469                 ) -> Result<Route, LightningError> {
1470                         self.0.borrow_mut().pop_front().unwrap()
1471                 }
1472         }
1473         impl ManualRouter {
1474                 fn expect_find_route(&self, result: Result<Route, LightningError>) {
1475                         self.0.borrow_mut().push_back(result);
1476                 }
1477         }
1478         impl Drop for ManualRouter {
1479                 fn drop(&mut self) {
1480                         if std::thread::panicking() {
1481                                 return;
1482                         }
1483                         assert!(self.0.borrow_mut().is_empty());
1484                 }
1485         }
1486
1487         #[test]
1488         fn retry_multi_path_single_failed_payment() {
1489                 // Tests that we can/will retry after a single path of an MPP payment failed immediately
1490                 let chanmon_cfgs = create_chanmon_cfgs(2);
1491                 let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
1492                 let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None, None]);
1493                 let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
1494
1495                 create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0, InitFeatures::known(), InitFeatures::known());
1496                 create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0, InitFeatures::known(), InitFeatures::known());
1497                 let chans = nodes[0].node.list_usable_channels();
1498                 let mut route = Route {
1499                         paths: vec![
1500                                 vec![RouteHop {
1501                                         pubkey: nodes[1].node.get_our_node_id(),
1502                                         node_features: NodeFeatures::known(),
1503                                         short_channel_id: chans[0].short_channel_id.unwrap(),
1504                                         channel_features: ChannelFeatures::known(),
1505                                         fee_msat: 10_000,
1506                                         cltv_expiry_delta: 100,
1507                                 }],
1508                                 vec![RouteHop {
1509                                         pubkey: nodes[1].node.get_our_node_id(),
1510                                         node_features: NodeFeatures::known(),
1511                                         short_channel_id: chans[1].short_channel_id.unwrap(),
1512                                         channel_features: ChannelFeatures::known(),
1513                                         fee_msat: 100_000_001, // Our default max-HTLC-value is 10% of the channel value, which this is one more than
1514                                         cltv_expiry_delta: 100,
1515                                 }],
1516                         ],
1517                         payee: Some(Payee::from_node_id(nodes[1].node.get_our_node_id())),
1518                 };
1519                 let router = ManualRouter(RefCell::new(VecDeque::new()));
1520                 router.expect_find_route(Ok(route.clone()));
1521                 // On retry, split the payment across both channels.
1522                 route.paths[0][0].fee_msat = 50_000_001;
1523                 route.paths[1][0].fee_msat = 50_000_000;
1524                 router.expect_find_route(Ok(route.clone()));
1525
1526                 let event_handler = |_: &_| { panic!(); };
1527                 let scorer = RefCell::new(TestScorer::new());
1528                 let invoice_payer = InvoicePayer::new(nodes[0].node, router, &scorer, nodes[0].logger, event_handler, RetryAttempts(1));
1529
1530                 assert!(invoice_payer.pay_invoice(&create_invoice_from_channelmanager(
1531                         &nodes[1].node, nodes[1].keys_manager, Currency::Bitcoin, Some(100_010_000), "Invoice".to_string()).unwrap())
1532                         .is_ok());
1533                 let htlc_msgs = nodes[0].node.get_and_clear_pending_msg_events();
1534                 assert_eq!(htlc_msgs.len(), 2);
1535                 check_added_monitors!(nodes[0], 2);
1536         }
1537
1538         #[test]
1539         fn immediate_retry_on_failure() {
1540                 // Tests that we can/will retry immediately after a failure
1541                 let chanmon_cfgs = create_chanmon_cfgs(2);
1542                 let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
1543                 let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None, None]);
1544                 let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
1545
1546                 create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0, InitFeatures::known(), InitFeatures::known());
1547                 create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0, InitFeatures::known(), InitFeatures::known());
1548                 let chans = nodes[0].node.list_usable_channels();
1549                 let mut route = Route {
1550                         paths: vec![
1551                                 vec![RouteHop {
1552                                         pubkey: nodes[1].node.get_our_node_id(),
1553                                         node_features: NodeFeatures::known(),
1554                                         short_channel_id: chans[0].short_channel_id.unwrap(),
1555                                         channel_features: ChannelFeatures::known(),
1556                                         fee_msat: 100_000_001, // Our default max-HTLC-value is 10% of the channel value, which this is one more than
1557                                         cltv_expiry_delta: 100,
1558                                 }],
1559                         ],
1560                         payee: Some(Payee::from_node_id(nodes[1].node.get_our_node_id())),
1561                 };
1562                 let router = ManualRouter(RefCell::new(VecDeque::new()));
1563                 router.expect_find_route(Ok(route.clone()));
1564                 // On retry, split the payment across both channels.
1565                 route.paths.push(route.paths[0].clone());
1566                 route.paths[0][0].short_channel_id = chans[1].short_channel_id.unwrap();
1567                 route.paths[0][0].fee_msat = 50_000_000;
1568                 route.paths[1][0].fee_msat = 50_000_001;
1569                 router.expect_find_route(Ok(route.clone()));
1570
1571                 let event_handler = |_: &_| { panic!(); };
1572                 let scorer = RefCell::new(TestScorer::new());
1573                 let invoice_payer = InvoicePayer::new(nodes[0].node, router, &scorer, nodes[0].logger, event_handler, RetryAttempts(1));
1574
1575                 assert!(invoice_payer.pay_invoice(&create_invoice_from_channelmanager(
1576                         &nodes[1].node, nodes[1].keys_manager, Currency::Bitcoin, Some(100_010_000), "Invoice".to_string()).unwrap())
1577                         .is_ok());
1578                 let htlc_msgs = nodes[0].node.get_and_clear_pending_msg_events();
1579                 assert_eq!(htlc_msgs.len(), 2);
1580                 check_added_monitors!(nodes[0], 2);
1581         }
1582
1583         #[test]
1584         fn no_extra_retries_on_back_to_back_fail() {
1585                 // In a previous release, we had a race where we may exceed the payment retry count if we
1586                 // get two failures in a row with the second having `all_paths_failed` set.
1587                 // Generally, when we give up trying to retry a payment, we don't know for sure what the
1588                 // current state of the ChannelManager event queue is. Specifically, we cannot be sure that
1589                 // there are not multiple additional `PaymentPathFailed` or even `PaymentSent` events
1590                 // pending which we will see later. Thus, when we previously removed the retry tracking map
1591                 // entry after a `all_paths_failed` `PaymentPathFailed` event, we may have dropped the
1592                 // retry entry even though more events for the same payment were still pending. This led to
1593                 // us retrying a payment again even though we'd already given up on it.
1594                 //
1595                 // We now have a separate event - `PaymentFailed` which indicates no HTLCs remain and which
1596                 // is used to remove the payment retry counter entries instead. This tests for the specific
1597                 // excess-retry case while also testing `PaymentFailed` generation.
1598
1599                 let chanmon_cfgs = create_chanmon_cfgs(3);
1600                 let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
1601                 let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]);
1602                 let nodes = create_network(3, &node_cfgs, &node_chanmgrs);
1603
1604                 let chan_1_scid = create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000_000, 0, InitFeatures::known(), InitFeatures::known()).0.contents.short_channel_id;
1605                 let chan_2_scid = create_announced_chan_between_nodes_with_value(&nodes, 1, 2, 10_000_000, 0, InitFeatures::known(), InitFeatures::known()).0.contents.short_channel_id;
1606
1607                 let mut route = Route {
1608                         paths: vec![
1609                                 vec![RouteHop {
1610                                         pubkey: nodes[1].node.get_our_node_id(),
1611                                         node_features: NodeFeatures::known(),
1612                                         short_channel_id: chan_1_scid,
1613                                         channel_features: ChannelFeatures::known(),
1614                                         fee_msat: 0,
1615                                         cltv_expiry_delta: 100,
1616                                 }, RouteHop {
1617                                         pubkey: nodes[2].node.get_our_node_id(),
1618                                         node_features: NodeFeatures::known(),
1619                                         short_channel_id: chan_2_scid,
1620                                         channel_features: ChannelFeatures::known(),
1621                                         fee_msat: 100_000_000,
1622                                         cltv_expiry_delta: 100,
1623                                 }],
1624                                 vec![RouteHop {
1625                                         pubkey: nodes[1].node.get_our_node_id(),
1626                                         node_features: NodeFeatures::known(),
1627                                         short_channel_id: chan_1_scid,
1628                                         channel_features: ChannelFeatures::known(),
1629                                         fee_msat: 0,
1630                                         cltv_expiry_delta: 100,
1631                                 }, RouteHop {
1632                                         pubkey: nodes[2].node.get_our_node_id(),
1633                                         node_features: NodeFeatures::known(),
1634                                         short_channel_id: chan_2_scid,
1635                                         channel_features: ChannelFeatures::known(),
1636                                         fee_msat: 100_000_000,
1637                                         cltv_expiry_delta: 100,
1638                                 }]
1639                         ],
1640                         payee: Some(Payee::from_node_id(nodes[2].node.get_our_node_id())),
1641                 };
1642                 let router = ManualRouter(RefCell::new(VecDeque::new()));
1643                 router.expect_find_route(Ok(route.clone()));
1644                 // On retry, we'll only be asked for one path
1645                 route.paths.remove(1);
1646                 router.expect_find_route(Ok(route.clone()));
1647
1648                 let expected_events: RefCell<VecDeque<&dyn Fn(&Event)>> = RefCell::new(VecDeque::new());
1649                 let event_handler = |event: &Event| {
1650                         let event_checker = expected_events.borrow_mut().pop_front().unwrap();
1651                         event_checker(event);
1652                 };
1653                 let scorer = RefCell::new(TestScorer::new());
1654                 let invoice_payer = InvoicePayer::new(nodes[0].node, router, &scorer, nodes[0].logger, event_handler, RetryAttempts(1));
1655
1656                 assert!(invoice_payer.pay_invoice(&create_invoice_from_channelmanager(
1657                         &nodes[1].node, nodes[1].keys_manager, Currency::Bitcoin, Some(100_010_000), "Invoice".to_string()).unwrap())
1658                         .is_ok());
1659                 let htlc_updates = SendEvent::from_node(&nodes[0]);
1660                 check_added_monitors!(nodes[0], 1);
1661                 assert_eq!(htlc_updates.msgs.len(), 1);
1662
1663                 nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &htlc_updates.msgs[0]);
1664                 nodes[1].node.handle_commitment_signed(&nodes[0].node.get_our_node_id(), &htlc_updates.commitment_msg);
1665                 check_added_monitors!(nodes[1], 1);
1666                 let (bs_first_raa, bs_first_cs) = get_revoke_commit_msgs!(nodes[1], nodes[0].node.get_our_node_id());
1667
1668                 nodes[0].node.handle_revoke_and_ack(&nodes[1].node.get_our_node_id(), &bs_first_raa);
1669                 check_added_monitors!(nodes[0], 1);
1670                 let second_htlc_updates = SendEvent::from_node(&nodes[0]);
1671
1672                 nodes[0].node.handle_commitment_signed(&nodes[1].node.get_our_node_id(), &bs_first_cs);
1673                 check_added_monitors!(nodes[0], 1);
1674                 let as_first_raa = get_event_msg!(nodes[0], MessageSendEvent::SendRevokeAndACK, nodes[1].node.get_our_node_id());
1675
1676                 nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &second_htlc_updates.msgs[0]);
1677                 nodes[1].node.handle_commitment_signed(&nodes[0].node.get_our_node_id(), &second_htlc_updates.commitment_msg);
1678                 check_added_monitors!(nodes[1], 1);
1679                 let bs_second_raa = get_event_msg!(nodes[1], MessageSendEvent::SendRevokeAndACK, nodes[0].node.get_our_node_id());
1680
1681                 nodes[1].node.handle_revoke_and_ack(&nodes[0].node.get_our_node_id(), &as_first_raa);
1682                 check_added_monitors!(nodes[1], 1);
1683                 let bs_fail_update = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
1684
1685                 nodes[0].node.handle_revoke_and_ack(&nodes[1].node.get_our_node_id(), &bs_second_raa);
1686                 check_added_monitors!(nodes[0], 1);
1687
1688                 nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &bs_fail_update.update_fail_htlcs[0]);
1689                 nodes[0].node.handle_commitment_signed(&nodes[1].node.get_our_node_id(), &bs_fail_update.commitment_signed);
1690                 check_added_monitors!(nodes[0], 1);
1691                 let (as_second_raa, as_third_cs) = get_revoke_commit_msgs!(nodes[0], nodes[1].node.get_our_node_id());
1692
1693                 nodes[1].node.handle_revoke_and_ack(&nodes[0].node.get_our_node_id(), &as_second_raa);
1694                 check_added_monitors!(nodes[1], 1);
1695                 let bs_second_fail_update = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
1696
1697                 nodes[1].node.handle_commitment_signed(&nodes[0].node.get_our_node_id(), &as_third_cs);
1698                 check_added_monitors!(nodes[1], 1);
1699                 let bs_third_raa = get_event_msg!(nodes[1], MessageSendEvent::SendRevokeAndACK, nodes[0].node.get_our_node_id());
1700
1701                 nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &bs_second_fail_update.update_fail_htlcs[0]);
1702                 nodes[0].node.handle_commitment_signed(&nodes[1].node.get_our_node_id(), &bs_second_fail_update.commitment_signed);
1703                 check_added_monitors!(nodes[0], 1);
1704
1705                 nodes[0].node.handle_revoke_and_ack(&nodes[1].node.get_our_node_id(), &bs_third_raa);
1706                 check_added_monitors!(nodes[0], 1);
1707                 let (as_third_raa, as_fourth_cs) = get_revoke_commit_msgs!(nodes[0], nodes[1].node.get_our_node_id());
1708
1709                 nodes[1].node.handle_revoke_and_ack(&nodes[0].node.get_our_node_id(), &as_third_raa);
1710                 check_added_monitors!(nodes[1], 1);
1711                 nodes[1].node.handle_commitment_signed(&nodes[0].node.get_our_node_id(), &as_fourth_cs);
1712                 check_added_monitors!(nodes[1], 1);
1713                 let bs_fourth_raa = get_event_msg!(nodes[1], MessageSendEvent::SendRevokeAndACK, nodes[0].node.get_our_node_id());
1714
1715                 nodes[0].node.handle_revoke_and_ack(&nodes[1].node.get_our_node_id(), &bs_fourth_raa);
1716                 check_added_monitors!(nodes[0], 1);
1717
1718                 // At this point A has sent two HTLCs which both failed due to lack of fee. It now has two
1719                 // pending `PaymentPathFailed` events, one with `all_paths_failed` unset, and the second
1720                 // with it set. The first event will use up the only retry we are allowed, with the second
1721                 // `PaymentPathFailed` being passed up to the user (us, in this case). Previously, we'd
1722                 // treated this as "HTLC complete" and dropped the retry counter, causing us to retry again
1723                 // if the final HTLC failed.
1724                 expected_events.borrow_mut().push_back(&|ev: &Event| {
1725                         if let Event::PaymentPathFailed { rejected_by_dest, all_paths_failed, .. } = ev {
1726                                 assert!(!rejected_by_dest);
1727                                 assert!(all_paths_failed);
1728                         } else { panic!("Unexpected event"); }
1729                 });
1730                 nodes[0].node.process_pending_events(&invoice_payer);
1731                 assert!(expected_events.borrow().is_empty());
1732
1733                 let retry_htlc_updates = SendEvent::from_node(&nodes[0]);
1734                 check_added_monitors!(nodes[0], 1);
1735
1736                 nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &retry_htlc_updates.msgs[0]);
1737                 commitment_signed_dance!(nodes[1], nodes[0], &retry_htlc_updates.commitment_msg, false, true);
1738                 let bs_fail_update = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
1739                 nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &bs_fail_update.update_fail_htlcs[0]);
1740                 commitment_signed_dance!(nodes[0], nodes[1], &bs_fail_update.commitment_signed, false, true);
1741
1742                 expected_events.borrow_mut().push_back(&|ev: &Event| {
1743                         if let Event::PaymentPathFailed { rejected_by_dest, all_paths_failed, .. } = ev {
1744                                 assert!(!rejected_by_dest);
1745                                 assert!(all_paths_failed);
1746                         } else { panic!("Unexpected event"); }
1747                 });
1748                 expected_events.borrow_mut().push_back(&|ev: &Event| {
1749                         if let Event::PaymentFailed { .. } = ev {
1750                         } else { panic!("Unexpected event"); }
1751                 });
1752                 nodes[0].node.process_pending_events(&invoice_payer);
1753                 assert!(expected_events.borrow().is_empty());
1754         }
1755 }