git.bitcoin.ninja Git - rust-lightning/blob - lightning-invoice/src/payment.rs

   1 // This file is Copyright its original authors, visible in version control
   2 // history.
   3 //
   4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
   5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
   7 // You may not use this file except in accordance with one or both of these
   8 // licenses.
   9
  10 //! A module for paying Lightning invoices 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: EventHandler>
 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 {
 160         payer: P,
 161         router: R,
 162         scorer: S,
 163         logger: L,
 164         event_handler: E,
 165         /// Caches the overall attempts at making a payment, which is updated prior to retrying.
 166         payment_cache: Mutex<HashMap<PaymentHash, usize>>,
 167         retry_attempts: RetryAttempts,
 168 }
 169
 170 /// A trait defining behavior of an [`Invoice`] payer.
 171 pub trait Payer {
 172         /// Returns the payer's node id.
 173         fn node_id(&self) -> PublicKey;
 174
 175         /// Returns the payer's channels.
 176         fn first_hops(&self) -> Vec<ChannelDetails>;
 177
 178         /// Sends a payment over the Lightning Network using the given [`Route`].
 179         fn send_payment(
 180                 &self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>
 181         ) -> Result<PaymentId, PaymentSendFailure>;
 182
 183         /// Sends a spontaneous payment over the Lightning Network using the given [`Route`].
 184         fn send_spontaneous_payment(
 185                 &self, route: &Route, payment_preimage: PaymentPreimage
 186         ) -> Result<PaymentId, PaymentSendFailure>;
 187
 188         /// Retries a failed payment path for the [`PaymentId`] using the given [`Route`].
 189         fn retry_payment(&self, route: &Route, payment_id: PaymentId) -> Result<(), PaymentSendFailure>;
 190
 191         /// Signals that no further retries for the given payment will occur.
 192         fn abandon_payment(&self, payment_id: PaymentId);
 193 }
 194
 195 /// A trait defining behavior for routing an [`Invoice`] payment.
 196 pub trait Router<S: Score> {
 197         /// Finds a [`Route`] between `payer` and `payee` for a payment with the given values.
 198         fn find_route(
 199                 &self, payer: &PublicKey, params: &RouteParameters, payment_hash: &PaymentHash,
 200                 first_hops: Option<&[&ChannelDetails]>, scorer: &S
 201         ) -> Result<Route, LightningError>;
 202 }
 203
 204 /// Number of attempts to retry payment path failures for an [`Invoice`].
 205 ///
 206 /// Note that this is the number of *path* failures, not full payment retries. For multi-path
 207 /// payments, if this is less than the total number of paths, we will never even retry all of the
 208 /// payment's paths.
 209 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
 210 pub struct RetryAttempts(pub usize);
 211
 212 /// An error that may occur when making a payment.
 213 #[derive(Clone, Debug)]
 214 pub enum PaymentError {
 215         /// An error resulting from the provided [`Invoice`] or payment hash.
 216         Invoice(&'static str),
 217         /// An error occurring when finding a route.
 218         Routing(LightningError),
 219         /// An error occurring when sending a payment.
 220         Sending(PaymentSendFailure),
 221 }
 222
 223 impl<P: Deref, R, S: Deref, L: Deref, E: EventHandler> InvoicePayer<P, R, S, L, E>
 224 where
 225         P::Target: Payer,
 226         R: for <'a> Router<<<S as Deref>::Target as LockableScore<'a>>::Locked>,
 227         S::Target: for <'a> LockableScore<'a>,
 228         L::Target: Logger,
 229 {
 230         /// Creates an invoice payer that retries failed payment paths.
 231         ///
 232         /// Will forward any [`Event::PaymentPathFailed`] events to the decorated `event_handler` once
 233         /// `retry_attempts` has been exceeded for a given [`Invoice`].
 234         pub fn new(
 235                 payer: P, router: R, scorer: S, logger: L, event_handler: E, retry_attempts: RetryAttempts
 236         ) -> Self {
 237                 Self {
 238                         payer,
 239                         router,
 240                         scorer,
 241                         logger,
 242                         event_handler,
 243                         payment_cache: Mutex::new(HashMap::new()),
 244                         retry_attempts,
 245                 }
 246         }
 247
 248         /// Pays the given [`Invoice`], caching it for later use in case a retry is needed.
 249         ///
 250         /// You should ensure that the `invoice.payment_hash()` is unique and the same payment_hash has
 251         /// never been paid before. Because [`InvoicePayer`] is stateless no effort is made to do so
 252         /// for you.
 253         pub fn pay_invoice(&self, invoice: &Invoice) -> Result<PaymentId, PaymentError> {
 254                 if invoice.amount_milli_satoshis().is_none() {
 255                         Err(PaymentError::Invoice("amount missing"))
 256                 } else {
 257                         self.pay_invoice_using_amount(invoice, None)
 258                 }
 259         }
 260
 261         /// Pays the given zero-value [`Invoice`] using the given amount, caching it for later use in
 262         /// case a retry is needed.
 263         ///
 264         /// You should ensure that the `invoice.payment_hash()` is unique and the same payment_hash has
 265         /// never been paid before. Because [`InvoicePayer`] is stateless no effort is made to do so
 266         /// for you.
 267         pub fn pay_zero_value_invoice(
 268                 &self, invoice: &Invoice, amount_msats: u64
 269         ) -> Result<PaymentId, PaymentError> {
 270                 if invoice.amount_milli_satoshis().is_some() {
 271                         Err(PaymentError::Invoice("amount unexpected"))
 272                 } else {
 273                         self.pay_invoice_using_amount(invoice, Some(amount_msats))
 274                 }
 275         }
 276
 277         fn pay_invoice_using_amount(
 278                 &self, invoice: &Invoice, amount_msats: Option<u64>
 279         ) -> Result<PaymentId, PaymentError> {
 280                 debug_assert!(invoice.amount_milli_satoshis().is_some() ^ amount_msats.is_some());
 281
 282                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 283                 match self.payment_cache.lock().unwrap().entry(payment_hash) {
 284                         hash_map::Entry::Occupied(_) => return Err(PaymentError::Invoice("payment pending")),
 285                         hash_map::Entry::Vacant(entry) => entry.insert(0),
 286                 };
 287
 288                 let payment_secret = Some(invoice.payment_secret().clone());
 289                 let mut payee = Payee::from_node_id(invoice.recover_payee_pub_key())
 290                         .with_expiry_time(expiry_time_from_unix_epoch(&invoice).as_secs())
 291                         .with_route_hints(invoice.route_hints());
 292                 if let Some(features) = invoice.features() {
 293                         payee = payee.with_features(features.clone());
 294                 }
 295                 let params = RouteParameters {
 296                         payee,
 297                         final_value_msat: invoice.amount_milli_satoshis().or(amount_msats).unwrap(),
 298                         final_cltv_expiry_delta: invoice.min_final_cltv_expiry() as u32,
 299                 };
 300
 301                 let send_payment = |route: &Route| {
 302                         self.payer.send_payment(route, payment_hash, &payment_secret)
 303                 };
 304                 self.pay_internal(&params, payment_hash, send_payment)
 305                         .map_err(|e| { self.payment_cache.lock().unwrap().remove(&payment_hash); e })
 306         }
 307
 308         /// Pays `pubkey` an amount using the hash of the given preimage, caching it for later use in
 309         /// case a retry is needed.
 310         ///
 311         /// You should ensure that `payment_preimage` is unique and that its `payment_hash` has never
 312         /// been paid before. Because [`InvoicePayer`] is stateless no effort is made to do so for you.
 313         pub fn pay_pubkey(
 314                 &self, pubkey: PublicKey, payment_preimage: PaymentPreimage, amount_msats: u64,
 315                 final_cltv_expiry_delta: u32
 316         ) -> Result<PaymentId, PaymentError> {
 317                 let payment_hash = PaymentHash(Sha256::hash(&payment_preimage.0).into_inner());
 318                 match self.payment_cache.lock().unwrap().entry(payment_hash) {
 319                         hash_map::Entry::Occupied(_) => return Err(PaymentError::Invoice("payment pending")),
 320                         hash_map::Entry::Vacant(entry) => entry.insert(0),
 321                 };
 322
 323                 let params = RouteParameters {
 324                         payee: Payee::for_keysend(pubkey),
 325                         final_value_msat: amount_msats,
 326                         final_cltv_expiry_delta,
 327                 };
 328
 329                 let send_payment = |route: &Route| {
 330                         self.payer.send_spontaneous_payment(route, payment_preimage)
 331                 };
 332                 self.pay_internal(&params, payment_hash, send_payment)
 333                         .map_err(|e| { self.payment_cache.lock().unwrap().remove(&payment_hash); e })
 334         }
 335
 336         fn pay_internal<F: FnOnce(&Route) -> Result<PaymentId, PaymentSendFailure> + Copy>(
 337                 &self, params: &RouteParameters, payment_hash: PaymentHash, send_payment: F,
 338         ) -> Result<PaymentId, PaymentError> {
 339                 if has_expired(params) {
 340                         log_trace!(self.logger, "Invoice expired prior to send for payment {}", log_bytes!(payment_hash.0));
 341                         return Err(PaymentError::Invoice("Invoice expired prior to send"));
 342                 }
 343
 344                 let payer = self.payer.node_id();
 345                 let first_hops = self.payer.first_hops();
 346                 let route = self.router.find_route(
 347                         &payer, params, &payment_hash, Some(&first_hops.iter().collect::<Vec<_>>()),
 348                         &self.scorer.lock()
 349                 ).map_err(|e| PaymentError::Routing(e))?;
 350
 351                 match send_payment(&route) {
 352                         Ok(payment_id) => Ok(payment_id),
 353                         Err(e) => match e {
 354                                 PaymentSendFailure::ParameterError(_) => Err(e),
 355                                 PaymentSendFailure::PathParameterError(_) => Err(e),
 356                                 PaymentSendFailure::AllFailedRetrySafe(_) => {
 357                                         let mut payment_cache = self.payment_cache.lock().unwrap();
 358                                         let retry_count = payment_cache.get_mut(&payment_hash).unwrap();
 359                                         if *retry_count >= self.retry_attempts.0 {
 360                                                 Err(e)
 361                                         } else {
 362                                                 *retry_count += 1;
 363                                                 std::mem::drop(payment_cache);
 364                                                 Ok(self.pay_internal(params, payment_hash, send_payment)?)
 365                                         }
 366                                 },
 367                                 PaymentSendFailure::PartialFailure { failed_paths_retry, payment_id, .. } => {
 368                                         if let Some(retry_data) = failed_paths_retry {
 369                                                 // Some paths were sent, even if we failed to send the full MPP value our
 370                                                 // recipient may misbehave and claim the funds, at which point we have to
 371                                                 // consider the payment sent, so return `Ok()` here, ignoring any retry
 372                                                 // errors.
 373                                                 let _ = self.retry_payment(payment_id, payment_hash, &retry_data);
 374                                                 Ok(payment_id)
 375                                         } else {
 376                                                 // This may happen if we send a payment and some paths fail, but
 377                                                 // only due to a temporary monitor failure or the like, implying
 378                                                 // they're really in-flight, but we haven't sent the initial
 379                                                 // HTLC-Add messages yet.
 380                                                 Ok(payment_id)
 381                                         }
 382                                 },
 383                         },
 384                 }.map_err(|e| PaymentError::Sending(e))
 385         }
 386
 387         fn retry_payment(
 388                 &self, payment_id: PaymentId, payment_hash: PaymentHash, params: &RouteParameters
 389         ) -> Result<(), ()> {
 390                 let max_payment_attempts = self.retry_attempts.0 + 1;
 391                 let attempts = *self.payment_cache.lock().unwrap()
 392                         .entry(payment_hash)
 393                         .and_modify(|attempts| *attempts += 1)
 394                         .or_insert(1);
 395
 396                 if attempts >= max_payment_attempts {
 397                         log_trace!(self.logger, "Payment {} exceeded maximum attempts; not retrying (attempts: {})", log_bytes!(payment_hash.0), attempts);
 398                         return Err(());
 399                 }
 400
 401                 if has_expired(params) {
 402                         log_trace!(self.logger, "Invoice expired for payment {}; not retrying (attempts: {})", log_bytes!(payment_hash.0), attempts);
 403                         return Err(());
 404                 }
 405
 406                 let payer = self.payer.node_id();
 407                 let first_hops = self.payer.first_hops();
 408                 let route = self.router.find_route(
 409                         &payer, &params, &payment_hash, Some(&first_hops.iter().collect::<Vec<_>>()),
 410                         &self.scorer.lock()
 411                 );
 412                 if route.is_err() {
 413                         log_trace!(self.logger, "Failed to find a route for payment {}; not retrying (attempts: {})", log_bytes!(payment_hash.0), attempts);
 414                         return Err(());
 415                 }
 416
 417                 match self.payer.retry_payment(&route.unwrap(), payment_id) {
 418                         Ok(()) => Ok(()),
 419                         Err(PaymentSendFailure::ParameterError(_)) |
 420                         Err(PaymentSendFailure::PathParameterError(_)) => {
 421                                 log_trace!(self.logger, "Failed to retry for payment {} due to bogus route/payment data, not retrying.", log_bytes!(payment_hash.0));
 422                                 Err(())
 423                         },
 424                         Err(PaymentSendFailure::AllFailedRetrySafe(_)) => {
 425                                 self.retry_payment(payment_id, payment_hash, params)
 426                         },
 427                         Err(PaymentSendFailure::PartialFailure { failed_paths_retry, .. }) => {
 428                                 if let Some(retry) = failed_paths_retry {
 429                                         // Always return Ok for the same reason as noted in pay_internal.
 430                                         let _ = self.retry_payment(payment_id, payment_hash, &retry);
 431                                 }
 432                                 Ok(())
 433                         },
 434                 }
 435         }
 436
 437         /// Removes the payment cached by the given payment hash.
 438         ///
 439         /// Should be called once a payment has failed or succeeded if not using [`InvoicePayer`] as an
 440         /// [`EventHandler`]. Otherwise, calling this method is unnecessary.
 441         pub fn remove_cached_payment(&self, payment_hash: &PaymentHash) {
 442                 self.payment_cache.lock().unwrap().remove(payment_hash);
 443         }
 444 }
 445
 446 fn expiry_time_from_unix_epoch(invoice: &Invoice) -> Duration {
 447         invoice.timestamp().duration_since(SystemTime::UNIX_EPOCH).unwrap() + invoice.expiry_time()
 448 }
 449
 450 fn has_expired(params: &RouteParameters) -> bool {
 451         if let Some(expiry_time) = params.payee.expiry_time {
 452                 Invoice::is_expired_from_epoch(&SystemTime::UNIX_EPOCH, Duration::from_secs(expiry_time))
 453         } else { false }
 454 }
 455
 456 impl<P: Deref, R, S: Deref, L: Deref, E: EventHandler> EventHandler for InvoicePayer<P, R, S, L, E>
 457 where
 458         P::Target: Payer,
 459         R: for <'a> Router<<<S as Deref>::Target as LockableScore<'a>>::Locked>,
 460         S::Target: for <'a> LockableScore<'a>,
 461         L::Target: Logger,
 462 {
 463         fn handle_event(&self, event: &Event) {
 464                 match event {
 465                         Event::PaymentPathFailed {
 466                                 payment_id, payment_hash, rejected_by_dest, path, short_channel_id, retry, ..
 467                         } => {
 468                                 if let Some(short_channel_id) = short_channel_id {
 469                                         let path = path.iter().collect::<Vec<_>>();
 470                                         self.scorer.lock().payment_path_failed(&path, *short_channel_id);
 471                                 }
 472
 473                                 if payment_id.is_none() {
 474                                         log_trace!(self.logger, "Payment {} has no id; not retrying", log_bytes!(payment_hash.0));
 475                                 } else if *rejected_by_dest {
 476                                         log_trace!(self.logger, "Payment {} rejected by destination; not retrying", log_bytes!(payment_hash.0));
 477                                         self.payer.abandon_payment(payment_id.unwrap());
 478                                 } else if retry.is_none() {
 479                                         log_trace!(self.logger, "Payment {} missing retry params; not retrying", log_bytes!(payment_hash.0));
 480                                         self.payer.abandon_payment(payment_id.unwrap());
 481                                 } else if self.retry_payment(payment_id.unwrap(), *payment_hash, retry.as_ref().unwrap()).is_ok() {
 482                                         // We retried at least somewhat, don't provide the PaymentPathFailed event to the user.
 483                                         return;
 484                                 } else {
 485                                         self.payer.abandon_payment(payment_id.unwrap());
 486                                 }
 487                         },
 488                         Event::PaymentFailed { payment_hash, .. } => {
 489                                 self.remove_cached_payment(&payment_hash);
 490                         },
 491                         Event::PaymentPathSuccessful { path, .. } => {
 492                                 let path = path.iter().collect::<Vec<_>>();
 493                                 self.scorer.lock().payment_path_successful(&path);
 494                         },
 495                         Event::PaymentSent { payment_hash, .. } => {
 496                                 let mut payment_cache = self.payment_cache.lock().unwrap();
 497                                 let attempts = payment_cache
 498                                         .remove(payment_hash)
 499                                         .map_or(1, |attempts| attempts + 1);
 500                                 log_trace!(self.logger, "Payment {} succeeded (attempts: {})", log_bytes!(payment_hash.0), attempts);
 501                         },
 502                         _ => {},
 503                 }
 504
 505                 // Delegate to the decorated event handler unless the payment is retried.
 506                 self.event_handler.handle_event(event)
 507         }
 508 }
 509
 510 #[cfg(test)]
 511 mod tests {
 512         use super::*;
 513         use crate::{DEFAULT_EXPIRY_TIME, InvoiceBuilder, Currency};
 514         use utils::create_invoice_from_channelmanager;
 515         use bitcoin_hashes::sha256::Hash as Sha256;
 516         use lightning::ln::PaymentPreimage;
 517         use lightning::ln::features::{ChannelFeatures, NodeFeatures, InitFeatures};
 518         use lightning::ln::functional_test_utils::*;
 519         use lightning::ln::msgs::{ChannelMessageHandler, ErrorAction, LightningError};
 520         use lightning::routing::network_graph::NodeId;
 521         use lightning::routing::router::{Payee, Route, RouteHop};
 522         use lightning::util::test_utils::TestLogger;
 523         use lightning::util::errors::APIError;
 524         use lightning::util::events::{Event, EventsProvider, MessageSendEvent, MessageSendEventsProvider};
 525         use secp256k1::{SecretKey, PublicKey, Secp256k1};
 526         use std::cell::RefCell;
 527         use std::collections::VecDeque;
 528         use std::time::{SystemTime, Duration};
 529
 530         fn invoice(payment_preimage: PaymentPreimage) -> Invoice {
 531                 let payment_hash = Sha256::hash(&payment_preimage.0);
 532                 let private_key = SecretKey::from_slice(&[42; 32]).unwrap();
 533                 InvoiceBuilder::new(Currency::Bitcoin)
 534                         .description("test".into())
 535                         .payment_hash(payment_hash)
 536                         .payment_secret(PaymentSecret([0; 32]))
 537                         .current_timestamp()
 538                         .min_final_cltv_expiry(144)
 539                         .amount_milli_satoshis(128)
 540                         .build_signed(|hash| {
 541                                 Secp256k1::new().sign_recoverable(hash, &private_key)
 542                         })
 543                         .unwrap()
 544         }
 545
 546         fn zero_value_invoice(payment_preimage: PaymentPreimage) -> Invoice {
 547                 let payment_hash = Sha256::hash(&payment_preimage.0);
 548                 let private_key = SecretKey::from_slice(&[42; 32]).unwrap();
 549                 InvoiceBuilder::new(Currency::Bitcoin)
 550                         .description("test".into())
 551                         .payment_hash(payment_hash)
 552                         .payment_secret(PaymentSecret([0; 32]))
 553                         .current_timestamp()
 554                         .min_final_cltv_expiry(144)
 555                         .build_signed(|hash| {
 556                                 Secp256k1::new().sign_recoverable(hash, &private_key)
 557                         })
 558                         .unwrap()
 559         }
 560
 561         fn expired_invoice(payment_preimage: PaymentPreimage) -> Invoice {
 562                 let payment_hash = Sha256::hash(&payment_preimage.0);
 563                 let private_key = SecretKey::from_slice(&[42; 32]).unwrap();
 564                 let timestamp = SystemTime::now()
 565                         .checked_sub(Duration::from_secs(DEFAULT_EXPIRY_TIME * 2))
 566                         .unwrap();
 567                 InvoiceBuilder::new(Currency::Bitcoin)
 568                         .description("test".into())
 569                         .payment_hash(payment_hash)
 570                         .payment_secret(PaymentSecret([0; 32]))
 571                         .timestamp(timestamp)
 572                         .min_final_cltv_expiry(144)
 573                         .amount_milli_satoshis(128)
 574                         .build_signed(|hash| {
 575                                 Secp256k1::new().sign_recoverable(hash, &private_key)
 576                         })
 577                         .unwrap()
 578         }
 579
 580         fn pubkey() -> PublicKey {
 581                 PublicKey::from_slice(&hex::decode("02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619").unwrap()[..]).unwrap()
 582         }
 583
 584         #[test]
 585         fn pays_invoice_on_first_attempt() {
 586                 let event_handled = core::cell::RefCell::new(false);
 587                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 588
 589                 let payment_preimage = PaymentPreimage([1; 32]);
 590                 let invoice = invoice(payment_preimage);
 591                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 592                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 593
 594                 let payer = TestPayer::new().expect_send(Amount::ForInvoice(final_value_msat));
 595                 let router = TestRouter {};
 596                 let scorer = RefCell::new(TestScorer::new());
 597                 let logger = TestLogger::new();
 598                 let invoice_payer =
 599                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(0));
 600
 601                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 602                 assert_eq!(*payer.attempts.borrow(), 1);
 603
 604                 invoice_payer.handle_event(&Event::PaymentSent {
 605                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
 606                 });
 607                 assert_eq!(*event_handled.borrow(), true);
 608                 assert_eq!(*payer.attempts.borrow(), 1);
 609         }
 610
 611         #[test]
 612         fn pays_invoice_on_retry() {
 613                 let event_handled = core::cell::RefCell::new(false);
 614                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 615
 616                 let payment_preimage = PaymentPreimage([1; 32]);
 617                 let invoice = invoice(payment_preimage);
 618                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 619                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 620
 621                 let payer = TestPayer::new()
 622                         .expect_send(Amount::ForInvoice(final_value_msat))
 623                         .expect_send(Amount::OnRetry(final_value_msat / 2));
 624                 let router = TestRouter {};
 625                 let scorer = RefCell::new(TestScorer::new());
 626                 let logger = TestLogger::new();
 627                 let invoice_payer =
 628                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 629
 630                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 631                 assert_eq!(*payer.attempts.borrow(), 1);
 632
 633                 let event = Event::PaymentPathFailed {
 634                         payment_id,
 635                         payment_hash,
 636                         network_update: None,
 637                         rejected_by_dest: false,
 638                         all_paths_failed: false,
 639                         path: TestRouter::path_for_value(final_value_msat),
 640                         short_channel_id: None,
 641                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 642                 };
 643                 invoice_payer.handle_event(&event);
 644                 assert_eq!(*event_handled.borrow(), false);
 645                 assert_eq!(*payer.attempts.borrow(), 2);
 646
 647                 invoice_payer.handle_event(&Event::PaymentSent {
 648                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
 649                 });
 650                 assert_eq!(*event_handled.borrow(), true);
 651                 assert_eq!(*payer.attempts.borrow(), 2);
 652         }
 653
 654         #[test]
 655         fn pays_invoice_on_partial_failure() {
 656                 let event_handler = |_: &_| { panic!() };
 657
 658                 let payment_preimage = PaymentPreimage([1; 32]);
 659                 let invoice = invoice(payment_preimage);
 660                 let retry = TestRouter::retry_for_invoice(&invoice);
 661                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 662
 663                 let payer = TestPayer::new()
 664                         .fails_with_partial_failure(retry.clone(), OnAttempt(1))
 665                         .fails_with_partial_failure(retry, OnAttempt(2))
 666                         .expect_send(Amount::ForInvoice(final_value_msat))
 667                         .expect_send(Amount::OnRetry(final_value_msat / 2))
 668                         .expect_send(Amount::OnRetry(final_value_msat / 2));
 669                 let router = TestRouter {};
 670                 let scorer = RefCell::new(TestScorer::new());
 671                 let logger = TestLogger::new();
 672                 let invoice_payer =
 673                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 674
 675                 assert!(invoice_payer.pay_invoice(&invoice).is_ok());
 676         }
 677
 678         #[test]
 679         fn retries_payment_path_for_unknown_payment() {
 680                 let event_handled = core::cell::RefCell::new(false);
 681                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 682
 683                 let payment_preimage = PaymentPreimage([1; 32]);
 684                 let invoice = invoice(payment_preimage);
 685                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 686                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 687
 688                 let payer = TestPayer::new()
 689                         .expect_send(Amount::OnRetry(final_value_msat / 2))
 690                         .expect_send(Amount::OnRetry(final_value_msat / 2));
 691                 let router = TestRouter {};
 692                 let scorer = RefCell::new(TestScorer::new());
 693                 let logger = TestLogger::new();
 694                 let invoice_payer =
 695                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 696
 697                 let payment_id = Some(PaymentId([1; 32]));
 698                 let event = Event::PaymentPathFailed {
 699                         payment_id,
 700                         payment_hash,
 701                         network_update: None,
 702                         rejected_by_dest: false,
 703                         all_paths_failed: false,
 704                         path: TestRouter::path_for_value(final_value_msat),
 705                         short_channel_id: None,
 706                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 707                 };
 708                 invoice_payer.handle_event(&event);
 709                 assert_eq!(*event_handled.borrow(), false);
 710                 assert_eq!(*payer.attempts.borrow(), 1);
 711
 712                 invoice_payer.handle_event(&event);
 713                 assert_eq!(*event_handled.borrow(), false);
 714                 assert_eq!(*payer.attempts.borrow(), 2);
 715
 716                 invoice_payer.handle_event(&Event::PaymentSent {
 717                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
 718                 });
 719                 assert_eq!(*event_handled.borrow(), true);
 720                 assert_eq!(*payer.attempts.borrow(), 2);
 721         }
 722
 723         #[test]
 724         fn fails_paying_invoice_after_max_retries() {
 725                 let event_handled = core::cell::RefCell::new(false);
 726                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 727
 728                 let payment_preimage = PaymentPreimage([1; 32]);
 729                 let invoice = invoice(payment_preimage);
 730                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 731
 732                 let payer = TestPayer::new()
 733                         .expect_send(Amount::ForInvoice(final_value_msat))
 734                         .expect_send(Amount::OnRetry(final_value_msat / 2))
 735                         .expect_send(Amount::OnRetry(final_value_msat / 2));
 736                 let router = TestRouter {};
 737                 let scorer = RefCell::new(TestScorer::new());
 738                 let logger = TestLogger::new();
 739                 let invoice_payer =
 740                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 741
 742                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 743                 assert_eq!(*payer.attempts.borrow(), 1);
 744
 745                 let event = Event::PaymentPathFailed {
 746                         payment_id,
 747                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 748                         network_update: None,
 749                         rejected_by_dest: false,
 750                         all_paths_failed: true,
 751                         path: TestRouter::path_for_value(final_value_msat),
 752                         short_channel_id: None,
 753                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 754                 };
 755                 invoice_payer.handle_event(&event);
 756                 assert_eq!(*event_handled.borrow(), false);
 757                 assert_eq!(*payer.attempts.borrow(), 2);
 758
 759                 let event = Event::PaymentPathFailed {
 760                         payment_id,
 761                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 762                         network_update: None,
 763                         rejected_by_dest: false,
 764                         all_paths_failed: false,
 765                         path: TestRouter::path_for_value(final_value_msat / 2),
 766                         short_channel_id: None,
 767                         retry: Some(RouteParameters {
 768                                 final_value_msat: final_value_msat / 2, ..TestRouter::retry_for_invoice(&invoice)
 769                         }),
 770                 };
 771                 invoice_payer.handle_event(&event);
 772                 assert_eq!(*event_handled.borrow(), false);
 773                 assert_eq!(*payer.attempts.borrow(), 3);
 774
 775                 invoice_payer.handle_event(&event);
 776                 assert_eq!(*event_handled.borrow(), true);
 777                 assert_eq!(*payer.attempts.borrow(), 3);
 778         }
 779
 780         #[test]
 781         fn fails_paying_invoice_with_missing_retry_params() {
 782                 let event_handled = core::cell::RefCell::new(false);
 783                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 784
 785                 let payment_preimage = PaymentPreimage([1; 32]);
 786                 let invoice = invoice(payment_preimage);
 787                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 788
 789                 let payer = TestPayer::new().expect_send(Amount::ForInvoice(final_value_msat));
 790                 let router = TestRouter {};
 791                 let scorer = RefCell::new(TestScorer::new());
 792                 let logger = TestLogger::new();
 793                 let invoice_payer =
 794                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 795
 796                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 797                 assert_eq!(*payer.attempts.borrow(), 1);
 798
 799                 let event = Event::PaymentPathFailed {
 800                         payment_id,
 801                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 802                         network_update: None,
 803                         rejected_by_dest: false,
 804                         all_paths_failed: false,
 805                         path: vec![],
 806                         short_channel_id: None,
 807                         retry: None,
 808                 };
 809                 invoice_payer.handle_event(&event);
 810                 assert_eq!(*event_handled.borrow(), true);
 811                 assert_eq!(*payer.attempts.borrow(), 1);
 812         }
 813
 814         #[test]
 815         fn fails_paying_invoice_after_expiration() {
 816                 let event_handled = core::cell::RefCell::new(false);
 817                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 818
 819                 let payer = TestPayer::new();
 820                 let router = TestRouter {};
 821                 let scorer = RefCell::new(TestScorer::new());
 822                 let logger = TestLogger::new();
 823                 let invoice_payer =
 824                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 825
 826                 let payment_preimage = PaymentPreimage([1; 32]);
 827                 let invoice = expired_invoice(payment_preimage);
 828                 if let PaymentError::Invoice(msg) = invoice_payer.pay_invoice(&invoice).unwrap_err() {
 829                         assert_eq!(msg, "Invoice expired prior to send");
 830                 } else { panic!("Expected Invoice Error"); }
 831         }
 832
 833         #[test]
 834         fn fails_retrying_invoice_after_expiration() {
 835                 let event_handled = core::cell::RefCell::new(false);
 836                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 837
 838                 let payment_preimage = PaymentPreimage([1; 32]);
 839                 let invoice = invoice(payment_preimage);
 840                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 841
 842                 let payer = TestPayer::new().expect_send(Amount::ForInvoice(final_value_msat));
 843                 let router = TestRouter {};
 844                 let scorer = RefCell::new(TestScorer::new());
 845                 let logger = TestLogger::new();
 846                 let invoice_payer =
 847                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 848
 849                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 850                 assert_eq!(*payer.attempts.borrow(), 1);
 851
 852                 let mut retry_data = TestRouter::retry_for_invoice(&invoice);
 853                 retry_data.payee.expiry_time = Some(SystemTime::now()
 854                         .checked_sub(Duration::from_secs(2)).unwrap()
 855                         .duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs());
 856                 let event = Event::PaymentPathFailed {
 857                         payment_id,
 858                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 859                         network_update: None,
 860                         rejected_by_dest: false,
 861                         all_paths_failed: false,
 862                         path: vec![],
 863                         short_channel_id: None,
 864                         retry: Some(retry_data),
 865                 };
 866                 invoice_payer.handle_event(&event);
 867                 assert_eq!(*event_handled.borrow(), true);
 868                 assert_eq!(*payer.attempts.borrow(), 1);
 869         }
 870
 871         #[test]
 872         fn fails_paying_invoice_after_retry_error() {
 873                 let event_handled = core::cell::RefCell::new(false);
 874                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 875
 876                 let payment_preimage = PaymentPreimage([1; 32]);
 877                 let invoice = invoice(payment_preimage);
 878                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 879
 880                 let payer = TestPayer::new()
 881                         .fails_on_attempt(2)
 882                         .expect_send(Amount::ForInvoice(final_value_msat))
 883                         .expect_send(Amount::OnRetry(final_value_msat / 2));
 884                 let router = TestRouter {};
 885                 let scorer = RefCell::new(TestScorer::new());
 886                 let logger = TestLogger::new();
 887                 let invoice_payer =
 888                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 889
 890                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 891                 assert_eq!(*payer.attempts.borrow(), 1);
 892
 893                 let event = Event::PaymentPathFailed {
 894                         payment_id,
 895                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 896                         network_update: None,
 897                         rejected_by_dest: false,
 898                         all_paths_failed: false,
 899                         path: TestRouter::path_for_value(final_value_msat / 2),
 900                         short_channel_id: None,
 901                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 902                 };
 903                 invoice_payer.handle_event(&event);
 904                 assert_eq!(*event_handled.borrow(), true);
 905                 assert_eq!(*payer.attempts.borrow(), 2);
 906         }
 907
 908         #[test]
 909         fn fails_paying_invoice_after_rejected_by_payee() {
 910                 let event_handled = core::cell::RefCell::new(false);
 911                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 912
 913                 let payment_preimage = PaymentPreimage([1; 32]);
 914                 let invoice = invoice(payment_preimage);
 915                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 916
 917                 let payer = TestPayer::new().expect_send(Amount::ForInvoice(final_value_msat));
 918                 let router = TestRouter {};
 919                 let scorer = RefCell::new(TestScorer::new());
 920                 let logger = TestLogger::new();
 921                 let invoice_payer =
 922                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 923
 924                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 925                 assert_eq!(*payer.attempts.borrow(), 1);
 926
 927                 let event = Event::PaymentPathFailed {
 928                         payment_id,
 929                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 930                         network_update: None,
 931                         rejected_by_dest: true,
 932                         all_paths_failed: false,
 933                         path: vec![],
 934                         short_channel_id: None,
 935                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 936                 };
 937                 invoice_payer.handle_event(&event);
 938                 assert_eq!(*event_handled.borrow(), true);
 939                 assert_eq!(*payer.attempts.borrow(), 1);
 940         }
 941
 942         #[test]
 943         fn fails_repaying_invoice_with_pending_payment() {
 944                 let event_handled = core::cell::RefCell::new(false);
 945                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 946
 947                 let payment_preimage = PaymentPreimage([1; 32]);
 948                 let invoice = invoice(payment_preimage);
 949                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 950
 951                 let payer = TestPayer::new()
 952                         .expect_send(Amount::ForInvoice(final_value_msat))
 953                         .expect_send(Amount::ForInvoice(final_value_msat));
 954                 let router = TestRouter {};
 955                 let scorer = RefCell::new(TestScorer::new());
 956                 let logger = TestLogger::new();
 957                 let invoice_payer =
 958                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(0));
 959
 960                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 961
 962                 // Cannot repay an invoice pending payment.
 963                 match invoice_payer.pay_invoice(&invoice) {
 964                         Err(PaymentError::Invoice("payment pending")) => {},
 965                         Err(_) => panic!("unexpected error"),
 966                         Ok(_) => panic!("expected invoice error"),
 967                 }
 968
 969                 // Can repay an invoice once cleared from cache.
 970                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 971                 invoice_payer.remove_cached_payment(&payment_hash);
 972                 assert!(invoice_payer.pay_invoice(&invoice).is_ok());
 973
 974                 // Cannot retry paying an invoice if cleared from cache.
 975                 invoice_payer.remove_cached_payment(&payment_hash);
 976                 let event = Event::PaymentPathFailed {
 977                         payment_id,
 978                         payment_hash,
 979                         network_update: None,
 980                         rejected_by_dest: false,
 981                         all_paths_failed: false,
 982                         path: vec![],
 983                         short_channel_id: None,
 984                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 985                 };
 986                 invoice_payer.handle_event(&event);
 987                 assert_eq!(*event_handled.borrow(), true);
 988         }
 989
 990         #[test]
 991         fn fails_paying_invoice_with_routing_errors() {
 992                 let payer = TestPayer::new();
 993                 let router = FailingRouter {};
 994                 let scorer = RefCell::new(TestScorer::new());
 995                 let logger = TestLogger::new();
 996                 let invoice_payer =
 997                         InvoicePayer::new(&payer, router, &scorer, &logger, |_: &_| {}, RetryAttempts(0));
 998
 999                 let payment_preimage = PaymentPreimage([1; 32]);
1000                 let invoice = invoice(payment_preimage);
1001                 match invoice_payer.pay_invoice(&invoice) {
1002                         Err(PaymentError::Routing(_)) => {},
1003                         Err(_) => panic!("unexpected error"),
1004                         Ok(_) => panic!("expected routing error"),
1005                 }
1006         }
1007
1008         #[test]
1009         fn fails_paying_invoice_with_sending_errors() {
1010                 let payment_preimage = PaymentPreimage([1; 32]);
1011                 let invoice = invoice(payment_preimage);
1012                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
1013
1014                 let payer = TestPayer::new()
1015                         .fails_on_attempt(1)
1016                         .expect_send(Amount::ForInvoice(final_value_msat));
1017                 let router = TestRouter {};
1018                 let scorer = RefCell::new(TestScorer::new());
1019                 let logger = TestLogger::new();
1020                 let invoice_payer =
1021                         InvoicePayer::new(&payer, router, &scorer, &logger, |_: &_| {}, RetryAttempts(0));
1022
1023                 match invoice_payer.pay_invoice(&invoice) {
1024                         Err(PaymentError::Sending(_)) => {},
1025                         Err(_) => panic!("unexpected error"),
1026                         Ok(_) => panic!("expected sending error"),
1027                 }
1028         }
1029
1030         #[test]
1031         fn pays_zero_value_invoice_using_amount() {
1032                 let event_handled = core::cell::RefCell::new(false);
1033                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1034
1035                 let payment_preimage = PaymentPreimage([1; 32]);
1036                 let invoice = zero_value_invoice(payment_preimage);
1037                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
1038                 let final_value_msat = 100;
1039
1040                 let payer = TestPayer::new().expect_send(Amount::ForInvoice(final_value_msat));
1041                 let router = TestRouter {};
1042                 let scorer = RefCell::new(TestScorer::new());
1043                 let logger = TestLogger::new();
1044                 let invoice_payer =
1045                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(0));
1046
1047                 let payment_id =
1048                         Some(invoice_payer.pay_zero_value_invoice(&invoice, final_value_msat).unwrap());
1049                 assert_eq!(*payer.attempts.borrow(), 1);
1050
1051                 invoice_payer.handle_event(&Event::PaymentSent {
1052                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
1053                 });
1054                 assert_eq!(*event_handled.borrow(), true);
1055                 assert_eq!(*payer.attempts.borrow(), 1);
1056         }
1057
1058         #[test]
1059         fn fails_paying_zero_value_invoice_with_amount() {
1060                 let event_handled = core::cell::RefCell::new(false);
1061                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1062
1063                 let payer = TestPayer::new();
1064                 let router = TestRouter {};
1065                 let scorer = RefCell::new(TestScorer::new());
1066                 let logger = TestLogger::new();
1067                 let invoice_payer =
1068                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(0));
1069
1070                 let payment_preimage = PaymentPreimage([1; 32]);
1071                 let invoice = invoice(payment_preimage);
1072
1073                 // Cannot repay an invoice pending payment.
1074                 match invoice_payer.pay_zero_value_invoice(&invoice, 100) {
1075                         Err(PaymentError::Invoice("amount unexpected")) => {},
1076                         Err(_) => panic!("unexpected error"),
1077                         Ok(_) => panic!("expected invoice error"),
1078                 }
1079         }
1080
1081         #[test]
1082         fn pays_pubkey_with_amount() {
1083                 let event_handled = core::cell::RefCell::new(false);
1084                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1085
1086                 let pubkey = pubkey();
1087                 let payment_preimage = PaymentPreimage([1; 32]);
1088                 let payment_hash = PaymentHash(Sha256::hash(&payment_preimage.0).into_inner());
1089                 let final_value_msat = 100;
1090                 let final_cltv_expiry_delta = 42;
1091
1092                 let payer = TestPayer::new()
1093                         .expect_send(Amount::Spontaneous(final_value_msat))
1094                         .expect_send(Amount::OnRetry(final_value_msat));
1095                 let router = TestRouter {};
1096                 let scorer = RefCell::new(TestScorer::new());
1097                 let logger = TestLogger::new();
1098                 let invoice_payer =
1099                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
1100
1101                 let payment_id = Some(invoice_payer.pay_pubkey(
1102                                 pubkey, payment_preimage, final_value_msat, final_cltv_expiry_delta
1103                         ).unwrap());
1104                 assert_eq!(*payer.attempts.borrow(), 1);
1105
1106                 let retry = RouteParameters {
1107                         payee: Payee::for_keysend(pubkey),
1108                         final_value_msat,
1109                         final_cltv_expiry_delta,
1110                 };
1111                 let event = Event::PaymentPathFailed {
1112                         payment_id,
1113                         payment_hash,
1114                         network_update: None,
1115                         rejected_by_dest: false,
1116                         all_paths_failed: false,
1117                         path: vec![],
1118                         short_channel_id: None,
1119                         retry: Some(retry),
1120                 };
1121                 invoice_payer.handle_event(&event);
1122                 assert_eq!(*event_handled.borrow(), false);
1123                 assert_eq!(*payer.attempts.borrow(), 2);
1124
1125                 invoice_payer.handle_event(&Event::PaymentSent {
1126                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
1127                 });
1128                 assert_eq!(*event_handled.borrow(), true);
1129                 assert_eq!(*payer.attempts.borrow(), 2);
1130         }
1131
1132         #[test]
1133         fn scores_failed_channel() {
1134                 let event_handled = core::cell::RefCell::new(false);
1135                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1136
1137                 let payment_preimage = PaymentPreimage([1; 32]);
1138                 let invoice = invoice(payment_preimage);
1139                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
1140                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
1141                 let path = TestRouter::path_for_value(final_value_msat);
1142                 let short_channel_id = Some(path[0].short_channel_id);
1143
1144                 // Expect that scorer is given short_channel_id upon handling the event.
1145                 let payer = TestPayer::new()
1146                         .expect_send(Amount::ForInvoice(final_value_msat))
1147                         .expect_send(Amount::OnRetry(final_value_msat / 2));
1148                 let router = TestRouter {};
1149                 let scorer = RefCell::new(TestScorer::new().expect(PaymentPath::Failure {
1150                         path: path.clone(), short_channel_id: path[0].short_channel_id,
1151                 }));
1152                 let logger = TestLogger::new();
1153                 let invoice_payer =
1154                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
1155
1156                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
1157                 let event = Event::PaymentPathFailed {
1158                         payment_id,
1159                         payment_hash,
1160                         network_update: None,
1161                         rejected_by_dest: false,
1162                         all_paths_failed: false,
1163                         path,
1164                         short_channel_id,
1165                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
1166                 };
1167                 invoice_payer.handle_event(&event);
1168         }
1169
1170         #[test]
1171         fn scores_successful_channels() {
1172                 let event_handled = core::cell::RefCell::new(false);
1173                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1174
1175                 let payment_preimage = PaymentPreimage([1; 32]);
1176                 let invoice = invoice(payment_preimage);
1177                 let payment_hash = Some(PaymentHash(invoice.payment_hash().clone().into_inner()));
1178                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
1179                 let route = TestRouter::route_for_value(final_value_msat);
1180
1181                 // Expect that scorer is given short_channel_id upon handling the event.
1182                 let payer = TestPayer::new().expect_send(Amount::ForInvoice(final_value_msat));
1183                 let router = TestRouter {};
1184                 let scorer = RefCell::new(TestScorer::new()
1185                         .expect(PaymentPath::Success { path: route.paths[0].clone() })
1186                         .expect(PaymentPath::Success { path: route.paths[1].clone() })
1187                 );
1188                 let logger = TestLogger::new();
1189                 let invoice_payer =
1190                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
1191
1192                 let payment_id = invoice_payer.pay_invoice(&invoice).unwrap();
1193                 let event = Event::PaymentPathSuccessful {
1194                         payment_id, payment_hash, path: route.paths[0].clone()
1195                 };
1196                 invoice_payer.handle_event(&event);
1197                 let event = Event::PaymentPathSuccessful {
1198                         payment_id, payment_hash, path: route.paths[1].clone()
1199                 };
1200                 invoice_payer.handle_event(&event);
1201         }
1202
1203         struct TestRouter;
1204
1205         impl TestRouter {
1206                 fn route_for_value(final_value_msat: u64) -> Route {
1207                         Route {
1208                                 paths: vec![
1209                                         vec![RouteHop {
1210                                                 pubkey: PublicKey::from_slice(&hex::decode("02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619").unwrap()[..]).unwrap(),
1211                                                 channel_features: ChannelFeatures::empty(),
1212                                                 node_features: NodeFeatures::empty(),
1213                                                 short_channel_id: 0, fee_msat: final_value_msat / 2, cltv_expiry_delta: 144
1214                                         }],
1215                                         vec![RouteHop {
1216                                                 pubkey: PublicKey::from_slice(&hex::decode("0324653eac434488002cc06bbfb7f10fe18991e35f9fe4302dbea6d2353dc0ab1c").unwrap()[..]).unwrap(),
1217                                                 channel_features: ChannelFeatures::empty(),
1218                                                 node_features: NodeFeatures::empty(),
1219                                                 short_channel_id: 1, fee_msat: final_value_msat / 2, cltv_expiry_delta: 144
1220                                         }],
1221                                 ],
1222                                 payee: None,
1223                         }
1224                 }
1225
1226                 fn path_for_value(final_value_msat: u64) -> Vec<RouteHop> {
1227                         TestRouter::route_for_value(final_value_msat).paths[0].clone()
1228                 }
1229
1230                 fn retry_for_invoice(invoice: &Invoice) -> RouteParameters {
1231                         let mut payee = Payee::from_node_id(invoice.recover_payee_pub_key())
1232                                 .with_expiry_time(expiry_time_from_unix_epoch(invoice).as_secs())
1233                                 .with_route_hints(invoice.route_hints());
1234                         if let Some(features) = invoice.features() {
1235                                 payee = payee.with_features(features.clone());
1236                         }
1237                         let final_value_msat = invoice.amount_milli_satoshis().unwrap() / 2;
1238                         RouteParameters {
1239                                 payee,
1240                                 final_value_msat,
1241                                 final_cltv_expiry_delta: invoice.min_final_cltv_expiry() as u32,
1242                         }
1243                 }
1244         }
1245
1246         impl<S: Score> Router<S> for TestRouter {
1247                 fn find_route(
1248                         &self, _payer: &PublicKey, params: &RouteParameters, _payment_hash: &PaymentHash,
1249                         _first_hops: Option<&[&ChannelDetails]>, _scorer: &S
1250                 ) -> Result<Route, LightningError> {
1251                         Ok(Route {
1252                                 payee: Some(params.payee.clone()), ..Self::route_for_value(params.final_value_msat)
1253                         })
1254                 }
1255         }
1256
1257         struct FailingRouter;
1258
1259         impl<S: Score> Router<S> for FailingRouter {
1260                 fn find_route(
1261                         &self, _payer: &PublicKey, _params: &RouteParameters, _payment_hash: &PaymentHash,
1262                         _first_hops: Option<&[&ChannelDetails]>, _scorer: &S
1263                 ) -> Result<Route, LightningError> {
1264                         Err(LightningError { err: String::new(), action: ErrorAction::IgnoreError })
1265                 }
1266         }
1267
1268         struct TestScorer {
1269                 expectations: Option<VecDeque<PaymentPath>>,
1270         }
1271
1272         #[derive(Debug)]
1273         enum PaymentPath {
1274                 Failure { path: Vec<RouteHop>, short_channel_id: u64 },
1275                 Success { path: Vec<RouteHop> },
1276         }
1277
1278         impl TestScorer {
1279                 fn new() -> Self {
1280                         Self {
1281                                 expectations: None,
1282                         }
1283                 }
1284
1285                 fn expect(mut self, expectation: PaymentPath) -> Self {
1286                         self.expectations.get_or_insert_with(|| VecDeque::new()).push_back(expectation);
1287                         self
1288                 }
1289         }
1290
1291         #[cfg(c_bindings)]
1292         impl lightning::util::ser::Writeable for TestScorer {
1293                 fn write<W: lightning::util::ser::Writer>(&self, _: &mut W) -> Result<(), std::io::Error> { unreachable!(); }
1294         }
1295
1296         impl Score for TestScorer {
1297                 fn channel_penalty_msat(
1298                         &self, _short_channel_id: u64, _send_amt: u64, _chan_amt: Option<u64>, _source: &NodeId, _target: &NodeId
1299                 ) -> u64 { 0 }
1300
1301                 fn payment_path_failed(&mut self, actual_path: &[&RouteHop], actual_short_channel_id: u64) {
1302                         if let Some(expectations) = &mut self.expectations {
1303                                 match expectations.pop_front() {
1304                                         Some(PaymentPath::Failure { path, short_channel_id }) => {
1305                                                 assert_eq!(actual_path, &path.iter().collect::<Vec<_>>()[..]);
1306                                                 assert_eq!(actual_short_channel_id, short_channel_id);
1307                                         },
1308                                         Some(PaymentPath::Success { path }) => {
1309                                                 panic!("Unexpected successful payment path: {:?}", path)
1310                                         },
1311                                         None => panic!("Unexpected payment_path_failed call: {:?}", actual_path),
1312                                 }
1313                         }
1314                 }
1315
1316                 fn payment_path_successful(&mut self, actual_path: &[&RouteHop]) {
1317                         if let Some(expectations) = &mut self.expectations {
1318                                 match expectations.pop_front() {
1319                                         Some(PaymentPath::Failure { path, .. }) => {
1320                                                 panic!("Unexpected payment path failure: {:?}", path)
1321                                         },
1322                                         Some(PaymentPath::Success { path }) => {
1323                                                 assert_eq!(actual_path, &path.iter().collect::<Vec<_>>()[..]);
1324                                         },
1325                                         None => panic!("Unexpected payment_path_successful call: {:?}", actual_path),
1326                                 }
1327                         }
1328                 }
1329         }
1330
1331         impl Drop for TestScorer {
1332                 fn drop(&mut self) {
1333                         if std::thread::panicking() {
1334                                 return;
1335                         }
1336
1337                         if let Some(expectations) = &self.expectations {
1338                                 if !expectations.is_empty() {
1339                                         panic!("Unsatisfied scorer expectations: {:?}", expectations);
1340                                 }
1341                         }
1342                 }
1343         }
1344
1345         struct TestPayer {
1346                 expectations: core::cell::RefCell<VecDeque<Amount>>,
1347                 attempts: core::cell::RefCell<usize>,
1348                 failing_on_attempt: core::cell::RefCell<HashMap<usize, PaymentSendFailure>>,
1349         }
1350
1351         #[derive(Clone, Debug, PartialEq, Eq)]
1352         enum Amount {
1353                 ForInvoice(u64),
1354                 Spontaneous(u64),
1355                 OnRetry(u64),
1356         }
1357
1358         struct OnAttempt(usize);
1359
1360         impl TestPayer {
1361                 fn new() -> Self {
1362                         Self {
1363                                 expectations: core::cell::RefCell::new(VecDeque::new()),
1364                                 attempts: core::cell::RefCell::new(0),
1365                                 failing_on_attempt: core::cell::RefCell::new(HashMap::new()),
1366                         }
1367                 }
1368
1369                 fn expect_send(self, value_msat: Amount) -> Self {
1370                         self.expectations.borrow_mut().push_back(value_msat);
1371                         self
1372                 }
1373
1374                 fn fails_on_attempt(self, attempt: usize) -> Self {
1375                         let failure = PaymentSendFailure::ParameterError(APIError::MonitorUpdateFailed);
1376                         self.fails_with(failure, OnAttempt(attempt))
1377                 }
1378
1379                 fn fails_with_partial_failure(self, retry: RouteParameters, attempt: OnAttempt) -> Self {
1380                         self.fails_with(PaymentSendFailure::PartialFailure {
1381                                 results: vec![],
1382                                 failed_paths_retry: Some(retry),
1383                                 payment_id: PaymentId([1; 32]),
1384                         }, attempt)
1385                 }
1386
1387                 fn fails_with(self, failure: PaymentSendFailure, attempt: OnAttempt) -> Self {
1388                         self.failing_on_attempt.borrow_mut().insert(attempt.0, failure);
1389                         self
1390                 }
1391
1392                 fn check_attempts(&self) -> Result<PaymentId, PaymentSendFailure> {
1393                         let mut attempts = self.attempts.borrow_mut();
1394                         *attempts += 1;
1395
1396                         match self.failing_on_attempt.borrow_mut().remove(&*attempts) {
1397                                 Some(failure) => Err(failure),
1398                                 None => Ok(PaymentId([1; 32])),
1399                         }
1400                 }
1401
1402                 fn check_value_msats(&self, actual_value_msats: Amount) {
1403                         let expected_value_msats = self.expectations.borrow_mut().pop_front();
1404                         if let Some(expected_value_msats) = expected_value_msats {
1405                                 assert_eq!(actual_value_msats, expected_value_msats);
1406                         } else {
1407                                 panic!("Unexpected amount: {:?}", actual_value_msats);
1408                         }
1409                 }
1410         }
1411
1412         impl Drop for TestPayer {
1413                 fn drop(&mut self) {
1414                         if std::thread::panicking() {
1415                                 return;
1416                         }
1417
1418                         if !self.expectations.borrow().is_empty() {
1419                                 panic!("Unsatisfied payment expectations: {:?}", self.expectations.borrow());
1420                         }
1421                 }
1422         }
1423
1424         impl Payer for TestPayer {
1425                 fn node_id(&self) -> PublicKey {
1426                         let secp_ctx = Secp256k1::new();
1427                         PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap())
1428                 }
1429
1430                 fn first_hops(&self) -> Vec<ChannelDetails> {
1431                         Vec::new()
1432                 }
1433
1434                 fn send_payment(
1435                         &self, route: &Route, _payment_hash: PaymentHash,
1436                         _payment_secret: &Option<PaymentSecret>
1437                 ) -> Result<PaymentId, PaymentSendFailure> {
1438                         self.check_value_msats(Amount::ForInvoice(route.get_total_amount()));
1439                         self.check_attempts()
1440                 }
1441
1442                 fn send_spontaneous_payment(
1443                         &self, route: &Route, _payment_preimage: PaymentPreimage,
1444                 ) -> Result<PaymentId, PaymentSendFailure> {
1445                         self.check_value_msats(Amount::Spontaneous(route.get_total_amount()));
1446                         self.check_attempts()
1447                 }
1448
1449                 fn retry_payment(
1450                         &self, route: &Route, _payment_id: PaymentId
1451                 ) -> Result<(), PaymentSendFailure> {
1452                         self.check_value_msats(Amount::OnRetry(route.get_total_amount()));
1453                         self.check_attempts().map(|_| ())
1454                 }
1455
1456                 fn abandon_payment(&self, _payment_id: PaymentId) { }
1457         }
1458
1459         // *** Full Featured Functional Tests with a Real ChannelManager ***
1460         struct ManualRouter(RefCell<VecDeque<Result<Route, LightningError>>>);
1461
1462         impl<S: Score> Router<S> for ManualRouter {
1463                 fn find_route(
1464                         &self, _payer: &PublicKey, _params: &RouteParameters, _payment_hash: &PaymentHash,
1465                         _first_hops: Option<&[&ChannelDetails]>, _scorer: &S
1466                 ) -> Result<Route, LightningError> {
1467                         self.0.borrow_mut().pop_front().unwrap()
1468                 }
1469         }
1470         impl ManualRouter {
1471                 fn expect_find_route(&self, result: Result<Route, LightningError>) {
1472                         self.0.borrow_mut().push_back(result);
1473                 }
1474         }
1475         impl Drop for ManualRouter {
1476                 fn drop(&mut self) {
1477                         if std::thread::panicking() {
1478                                 return;
1479                         }
1480                         assert!(self.0.borrow_mut().is_empty());
1481                 }
1482         }
1483
1484         #[test]
1485         fn retry_multi_path_single_failed_payment() {
1486                 // Tests that we can/will retry after a single path of an MPP payment failed immediately
1487                 let chanmon_cfgs = create_chanmon_cfgs(2);
1488                 let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
1489                 let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None, None]);
1490                 let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
1491
1492                 create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0, InitFeatures::known(), InitFeatures::known());
1493                 create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0, InitFeatures::known(), InitFeatures::known());
1494                 let chans = nodes[0].node.list_usable_channels();
1495                 let mut route = Route {
1496                         paths: vec![
1497                                 vec![RouteHop {
1498                                         pubkey: nodes[1].node.get_our_node_id(),
1499                                         node_features: NodeFeatures::known(),
1500                                         short_channel_id: chans[0].short_channel_id.unwrap(),
1501                                         channel_features: ChannelFeatures::known(),
1502                                         fee_msat: 10_000,
1503                                         cltv_expiry_delta: 100,
1504                                 }],
1505                                 vec![RouteHop {
1506                                         pubkey: nodes[1].node.get_our_node_id(),
1507                                         node_features: NodeFeatures::known(),
1508                                         short_channel_id: chans[1].short_channel_id.unwrap(),
1509                                         channel_features: ChannelFeatures::known(),
1510                                         fee_msat: 100_000_001, // Our default max-HTLC-value is 10% of the channel value, which this is one more than
1511                                         cltv_expiry_delta: 100,
1512                                 }],
1513                         ],
1514                         payee: Some(Payee::from_node_id(nodes[1].node.get_our_node_id())),
1515                 };
1516                 let router = ManualRouter(RefCell::new(VecDeque::new()));
1517                 router.expect_find_route(Ok(route.clone()));
1518                 // On retry, split the payment across both channels.
1519                 route.paths[0][0].fee_msat = 50_000_001;
1520                 route.paths[1][0].fee_msat = 50_000_000;
1521                 router.expect_find_route(Ok(route.clone()));
1522
1523                 let event_handler = |_: &_| { panic!(); };
1524                 let scorer = RefCell::new(TestScorer::new());
1525                 let invoice_payer = InvoicePayer::new(nodes[0].node, router, &scorer, nodes[0].logger, event_handler, RetryAttempts(1));
1526
1527                 assert!(invoice_payer.pay_invoice(&create_invoice_from_channelmanager(
1528                         &nodes[1].node, nodes[1].keys_manager, Currency::Bitcoin, Some(100_010_000), "Invoice".to_string()).unwrap())
1529                         .is_ok());
1530                 let htlc_msgs = nodes[0].node.get_and_clear_pending_msg_events();
1531                 assert_eq!(htlc_msgs.len(), 2);
1532                 check_added_monitors!(nodes[0], 2);
1533         }
1534
1535         #[test]
1536         fn immediate_retry_on_failure() {
1537                 // Tests that we can/will retry immediately after a failure
1538                 let chanmon_cfgs = create_chanmon_cfgs(2);
1539                 let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
1540                 let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None, None]);
1541                 let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
1542
1543                 create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0, InitFeatures::known(), InitFeatures::known());
1544                 create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0, InitFeatures::known(), InitFeatures::known());
1545                 let chans = nodes[0].node.list_usable_channels();
1546                 let mut route = Route {
1547                         paths: vec![
1548                                 vec![RouteHop {
1549                                         pubkey: nodes[1].node.get_our_node_id(),
1550                                         node_features: NodeFeatures::known(),
1551                                         short_channel_id: chans[0].short_channel_id.unwrap(),
1552                                         channel_features: ChannelFeatures::known(),
1553                                         fee_msat: 100_000_001, // Our default max-HTLC-value is 10% of the channel value, which this is one more than
1554                                         cltv_expiry_delta: 100,
1555                                 }],
1556                         ],
1557                         payee: Some(Payee::from_node_id(nodes[1].node.get_our_node_id())),
1558                 };
1559                 let router = ManualRouter(RefCell::new(VecDeque::new()));
1560                 router.expect_find_route(Ok(route.clone()));
1561                 // On retry, split the payment across both channels.
1562                 route.paths.push(route.paths[0].clone());
1563                 route.paths[0][0].short_channel_id = chans[1].short_channel_id.unwrap();
1564                 route.paths[0][0].fee_msat = 50_000_000;
1565                 route.paths[1][0].fee_msat = 50_000_001;
1566                 router.expect_find_route(Ok(route.clone()));
1567
1568                 let event_handler = |_: &_| { panic!(); };
1569                 let scorer = RefCell::new(TestScorer::new());
1570                 let invoice_payer = InvoicePayer::new(nodes[0].node, router, &scorer, nodes[0].logger, event_handler, RetryAttempts(1));
1571
1572                 assert!(invoice_payer.pay_invoice(&create_invoice_from_channelmanager(
1573                         &nodes[1].node, nodes[1].keys_manager, Currency::Bitcoin, Some(100_010_000), "Invoice".to_string()).unwrap())
1574                         .is_ok());
1575                 let htlc_msgs = nodes[0].node.get_and_clear_pending_msg_events();
1576                 assert_eq!(htlc_msgs.len(), 2);
1577                 check_added_monitors!(nodes[0], 2);
1578         }
1579
1580         #[test]
1581         fn no_extra_retries_on_back_to_back_fail() {
1582                 // In a previous release, we had a race where we may exceed the payment retry count if we
1583                 // get two failures in a row with the second having `all_paths_failed` set.
1584                 // Generally, when we give up trying to retry a payment, we don't know for sure what the
1585                 // current state of the ChannelManager event queue is. Specifically, we cannot be sure that
1586                 // there are not multiple additional `PaymentPathFailed` or even `PaymentSent` events
1587                 // pending which we will see later. Thus, when we previously removed the retry tracking map
1588                 // entry after a `all_paths_failed` `PaymentPathFailed` event, we may have dropped the
1589                 // retry entry even though more events for the same payment were still pending. This led to
1590                 // us retrying a payment again even though we'd already given up on it.
1591                 //
1592                 // We now have a separate event - `PaymentFailed` which indicates no HTLCs remain and which
1593                 // is used to remove the payment retry counter entries instead. This tests for the specific
1594                 // excess-retry case while also testing `PaymentFailed` generation.
1595
1596                 let chanmon_cfgs = create_chanmon_cfgs(3);
1597                 let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
1598                 let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]);
1599                 let nodes = create_network(3, &node_cfgs, &node_chanmgrs);
1600
1601                 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;
1602                 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;
1603
1604                 let mut route = Route {
1605                         paths: vec![
1606                                 vec![RouteHop {
1607                                         pubkey: nodes[1].node.get_our_node_id(),
1608                                         node_features: NodeFeatures::known(),
1609                                         short_channel_id: chan_1_scid,
1610                                         channel_features: ChannelFeatures::known(),
1611                                         fee_msat: 0,
1612                                         cltv_expiry_delta: 100,
1613                                 }, RouteHop {
1614                                         pubkey: nodes[2].node.get_our_node_id(),
1615                                         node_features: NodeFeatures::known(),
1616                                         short_channel_id: chan_2_scid,
1617                                         channel_features: ChannelFeatures::known(),
1618                                         fee_msat: 100_000_000,
1619                                         cltv_expiry_delta: 100,
1620                                 }],
1621                                 vec![RouteHop {
1622                                         pubkey: nodes[1].node.get_our_node_id(),
1623                                         node_features: NodeFeatures::known(),
1624                                         short_channel_id: chan_1_scid,
1625                                         channel_features: ChannelFeatures::known(),
1626                                         fee_msat: 0,
1627                                         cltv_expiry_delta: 100,
1628                                 }, RouteHop {
1629                                         pubkey: nodes[2].node.get_our_node_id(),
1630                                         node_features: NodeFeatures::known(),
1631                                         short_channel_id: chan_2_scid,
1632                                         channel_features: ChannelFeatures::known(),
1633                                         fee_msat: 100_000_000,
1634                                         cltv_expiry_delta: 100,
1635                                 }]
1636                         ],
1637                         payee: Some(Payee::from_node_id(nodes[2].node.get_our_node_id())),
1638                 };
1639                 let router = ManualRouter(RefCell::new(VecDeque::new()));
1640                 router.expect_find_route(Ok(route.clone()));
1641                 // On retry, we'll only be asked for one path
1642                 route.paths.remove(1);
1643                 router.expect_find_route(Ok(route.clone()));
1644
1645                 let expected_events: RefCell<VecDeque<&dyn Fn(&Event)>> = RefCell::new(VecDeque::new());
1646                 let event_handler = |event: &Event| {
1647                         let event_checker = expected_events.borrow_mut().pop_front().unwrap();
1648                         event_checker(event);
1649                 };
1650                 let scorer = RefCell::new(TestScorer::new());
1651                 let invoice_payer = InvoicePayer::new(nodes[0].node, router, &scorer, nodes[0].logger, event_handler, RetryAttempts(1));
1652
1653                 assert!(invoice_payer.pay_invoice(&create_invoice_from_channelmanager(
1654                         &nodes[1].node, nodes[1].keys_manager, Currency::Bitcoin, Some(100_010_000), "Invoice".to_string()).unwrap())
1655                         .is_ok());
1656                 let htlc_updates = SendEvent::from_node(&nodes[0]);
1657                 check_added_monitors!(nodes[0], 1);
1658                 assert_eq!(htlc_updates.msgs.len(), 1);
1659
1660                 nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &htlc_updates.msgs[0]);
1661                 nodes[1].node.handle_commitment_signed(&nodes[0].node.get_our_node_id(), &htlc_updates.commitment_msg);
1662                 check_added_monitors!(nodes[1], 1);
1663                 let (bs_first_raa, bs_first_cs) = get_revoke_commit_msgs!(nodes[1], nodes[0].node.get_our_node_id());
1664
1665                 nodes[0].node.handle_revoke_and_ack(&nodes[1].node.get_our_node_id(), &bs_first_raa);
1666                 check_added_monitors!(nodes[0], 1);
1667                 let second_htlc_updates = SendEvent::from_node(&nodes[0]);
1668
1669                 nodes[0].node.handle_commitment_signed(&nodes[1].node.get_our_node_id(), &bs_first_cs);
1670                 check_added_monitors!(nodes[0], 1);
1671                 let as_first_raa = get_event_msg!(nodes[0], MessageSendEvent::SendRevokeAndACK, nodes[1].node.get_our_node_id());
1672
1673                 nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &second_htlc_updates.msgs[0]);
1674                 nodes[1].node.handle_commitment_signed(&nodes[0].node.get_our_node_id(), &second_htlc_updates.commitment_msg);
1675                 check_added_monitors!(nodes[1], 1);
1676                 let bs_second_raa = get_event_msg!(nodes[1], MessageSendEvent::SendRevokeAndACK, nodes[0].node.get_our_node_id());
1677
1678                 nodes[1].node.handle_revoke_and_ack(&nodes[0].node.get_our_node_id(), &as_first_raa);
1679                 check_added_monitors!(nodes[1], 1);
1680                 let bs_fail_update = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
1681
1682                 nodes[0].node.handle_revoke_and_ack(&nodes[1].node.get_our_node_id(), &bs_second_raa);
1683                 check_added_monitors!(nodes[0], 1);
1684
1685                 nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &bs_fail_update.update_fail_htlcs[0]);
1686                 nodes[0].node.handle_commitment_signed(&nodes[1].node.get_our_node_id(), &bs_fail_update.commitment_signed);
1687                 check_added_monitors!(nodes[0], 1);
1688                 let (as_second_raa, as_third_cs) = get_revoke_commit_msgs!(nodes[0], nodes[1].node.get_our_node_id());
1689
1690                 nodes[1].node.handle_revoke_and_ack(&nodes[0].node.get_our_node_id(), &as_second_raa);
1691                 check_added_monitors!(nodes[1], 1);
1692                 let bs_second_fail_update = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
1693
1694                 nodes[1].node.handle_commitment_signed(&nodes[0].node.get_our_node_id(), &as_third_cs);
1695                 check_added_monitors!(nodes[1], 1);
1696                 let bs_third_raa = get_event_msg!(nodes[1], MessageSendEvent::SendRevokeAndACK, nodes[0].node.get_our_node_id());
1697
1698                 nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &bs_second_fail_update.update_fail_htlcs[0]);
1699                 nodes[0].node.handle_commitment_signed(&nodes[1].node.get_our_node_id(), &bs_second_fail_update.commitment_signed);
1700                 check_added_monitors!(nodes[0], 1);
1701
1702                 nodes[0].node.handle_revoke_and_ack(&nodes[1].node.get_our_node_id(), &bs_third_raa);
1703                 check_added_monitors!(nodes[0], 1);
1704                 let (as_third_raa, as_fourth_cs) = get_revoke_commit_msgs!(nodes[0], nodes[1].node.get_our_node_id());
1705
1706                 nodes[1].node.handle_revoke_and_ack(&nodes[0].node.get_our_node_id(), &as_third_raa);
1707                 check_added_monitors!(nodes[1], 1);
1708                 nodes[1].node.handle_commitment_signed(&nodes[0].node.get_our_node_id(), &as_fourth_cs);
1709                 check_added_monitors!(nodes[1], 1);
1710                 let bs_fourth_raa = get_event_msg!(nodes[1], MessageSendEvent::SendRevokeAndACK, nodes[0].node.get_our_node_id());
1711
1712                 nodes[0].node.handle_revoke_and_ack(&nodes[1].node.get_our_node_id(), &bs_fourth_raa);
1713                 check_added_monitors!(nodes[0], 1);
1714
1715                 // At this point A has sent two HTLCs which both failed due to lack of fee. It now has two
1716                 // pending `PaymentPathFailed` events, one with `all_paths_failed` unset, and the second
1717                 // with it set. The first event will use up the only retry we are allowed, with the second
1718                 // `PaymentPathFailed` being passed up to the user (us, in this case). Previously, we'd
1719                 // treated this as "HTLC complete" and dropped the retry counter, causing us to retry again
1720                 // if the final HTLC failed.
1721                 expected_events.borrow_mut().push_back(&|ev: &Event| {
1722                         if let Event::PaymentPathFailed { rejected_by_dest, all_paths_failed, .. } = ev {
1723                                 assert!(!rejected_by_dest);
1724                                 assert!(all_paths_failed);
1725                         } else { panic!("Unexpected event"); }
1726                 });
1727                 nodes[0].node.process_pending_events(&invoice_payer);
1728                 assert!(expected_events.borrow().is_empty());
1729
1730                 let retry_htlc_updates = SendEvent::from_node(&nodes[0]);
1731                 check_added_monitors!(nodes[0], 1);
1732
1733                 nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &retry_htlc_updates.msgs[0]);
1734                 commitment_signed_dance!(nodes[1], nodes[0], &retry_htlc_updates.commitment_msg, false, true);
1735                 let bs_fail_update = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
1736                 nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &bs_fail_update.update_fail_htlcs[0]);
1737                 commitment_signed_dance!(nodes[0], nodes[1], &bs_fail_update.commitment_signed, false, true);
1738
1739                 expected_events.borrow_mut().push_back(&|ev: &Event| {
1740                         if let Event::PaymentPathFailed { rejected_by_dest, all_paths_failed, .. } = ev {
1741                                 assert!(!rejected_by_dest);
1742                                 assert!(all_paths_failed);
1743                         } else { panic!("Unexpected event"); }
1744                 });
1745                 expected_events.borrow_mut().push_back(&|ev: &Event| {
1746                         if let Event::PaymentFailed { .. } = ev {
1747                         } else { panic!("Unexpected event"); }
1748                 });
1749                 nodes[0].node.process_pending_events(&invoice_payer);
1750                 assert!(expected_events.borrow().is_empty());
1751         }
1752 }