_ 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 capable of retrying failed payments. It accomplishes this by implementing
  19 //! [`EventHandler`] which decorates a user-provided handler. It will intercept any
  20 //! [`Event::PaymentPathFailed`] events and retry the failed paths for a fixed number of total
  21 //! attempts or until retry is no longer possible. In such a situation, [`InvoicePayer`] will pass
  22 //! along the events to the user-provided handler.
  23 //!
  24 //! # Example
  25 //!
  26 //! ```
  27 //! # extern crate lightning;
  28 //! # extern crate lightning_invoice;
  29 //! # extern crate secp256k1;
  30 //! #
  31 //! # use lightning::ln::{PaymentHash, PaymentPreimage, PaymentSecret};
  32 //! # use lightning::ln::channelmanager::{ChannelDetails, PaymentId, PaymentSendFailure};
  33 //! # use lightning::ln::msgs::LightningError;
  34 //! # use lightning::routing::scoring::Score;
  35 //! # use lightning::routing::network_graph::NodeId;
  36 //! # use lightning::routing::router::{Route, RouteHop, RouteParameters};
  37 //! # use lightning::util::events::{Event, EventHandler, EventsProvider};
  38 //! # use lightning::util::logger::{Logger, Record};
  39 //! # use lightning::util::ser::{Writeable, Writer};
  40 //! # use lightning_invoice::Invoice;
  41 //! # use lightning_invoice::payment::{InvoicePayer, Payer, RetryAttempts, Router};
  42 //! # use secp256k1::key::PublicKey;
  43 //! # use std::cell::RefCell;
  44 //! # use std::ops::Deref;
  45 //! #
  46 //! # struct FakeEventProvider {}
  47 //! # impl EventsProvider for FakeEventProvider {
  48 //! #     fn process_pending_events<H: Deref>(&self, handler: H) where H::Target: EventHandler {}
  49 //! # }
  50 //! #
  51 //! # struct FakePayer {}
  52 //! # impl Payer for FakePayer {
  53 //! #     fn node_id(&self) -> PublicKey { unimplemented!() }
  54 //! #     fn first_hops(&self) -> Vec<ChannelDetails> { unimplemented!() }
  55 //! #     fn send_payment(
  56 //! #         &self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>
  57 //! #     ) -> Result<PaymentId, PaymentSendFailure> { unimplemented!() }
  58 //! #     fn send_spontaneous_payment(
  59 //! #         &self, route: &Route, payment_preimage: PaymentPreimage
  60 //! #     ) -> Result<PaymentId, PaymentSendFailure> { unimplemented!() }
  61 //! #     fn retry_payment(
  62 //! #         &self, route: &Route, payment_id: PaymentId
  63 //! #     ) -> Result<(), PaymentSendFailure> { unimplemented!() }
  64 //! # }
  65 //! #
  66 //! # struct FakeRouter {};
  67 //! # impl<S: Score> Router<S> for FakeRouter {
  68 //! #     fn find_route(
  69 //! #         &self, payer: &PublicKey, params: &RouteParameters, payment_hash: &PaymentHash,
  70 //! #         first_hops: Option<&[&ChannelDetails]>, scorer: &S
  71 //! #     ) -> Result<Route, LightningError> { unimplemented!() }
  72 //! # }
  73 //! #
  74 //! # struct FakeScorer {};
  75 //! # impl Writeable for FakeScorer {
  76 //! #     fn write<W: Writer>(&self, w: &mut W) -> Result<(), std::io::Error> { unimplemented!(); }
  77 //! # }
  78 //! # impl Score for FakeScorer {
  79 //! #     fn channel_penalty_msat(
  80 //! #         &self, _short_channel_id: u64, _send_amt: u64, _chan_amt: Option<u64>, _source: &NodeId, _target: &NodeId
  81 //! #     ) -> u64 { 0 }
  82 //! #     fn payment_path_failed(&mut self, _path: &[&RouteHop], _short_channel_id: u64) {}
  83 //! # }
  84 //! #
  85 //! # struct FakeLogger {};
  86 //! # impl Logger for FakeLogger {
  87 //! #     fn log(&self, record: &Record) { unimplemented!() }
  88 //! # }
  89 //! #
  90 //! # fn main() {
  91 //! let event_handler = |event: &Event| {
  92 //!     match event {
  93 //!         Event::PaymentPathFailed { .. } => println!("payment failed after retries"),
  94 //!         Event::PaymentSent { .. } => println!("payment successful"),
  95 //!         _ => {},
  96 //!     }
  97 //! };
  98 //! # let payer = FakePayer {};
  99 //! # let router = FakeRouter {};
 100 //! # let scorer = RefCell::new(FakeScorer {});
 101 //! # let logger = FakeLogger {};
 102 //! let invoice_payer = InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 103 //!
 104 //! let invoice = "...";
 105 //! let invoice = invoice.parse::<Invoice>().unwrap();
 106 //! invoice_payer.pay_invoice(&invoice).unwrap();
 107 //!
 108 //! # let event_provider = FakeEventProvider {};
 109 //! loop {
 110 //!     event_provider.process_pending_events(&invoice_payer);
 111 //! }
 112 //! # }
 113 //! ```
 114 //!
 115 //! # Note
 116 //!
 117 //! The [`Route`] is computed before each payment attempt. Any updates affecting path finding such
 118 //! as updates to the network graph or changes to channel scores should be applied prior to
 119 //! retries, typically by way of composing [`EventHandler`]s accordingly.
 120
 121 use crate::Invoice;
 122
 123 use bitcoin_hashes::Hash;
 124 use bitcoin_hashes::sha256::Hash as Sha256;
 125
 126 use lightning::ln::{PaymentHash, PaymentPreimage, PaymentSecret};
 127 use lightning::ln::channelmanager::{ChannelDetails, PaymentId, PaymentSendFailure};
 128 use lightning::ln::msgs::LightningError;
 129 use lightning::routing::scoring::{LockableScore, Score};
 130 use lightning::routing::router::{Payee, Route, RouteParameters};
 131 use lightning::util::events::{Event, EventHandler};
 132 use lightning::util::logger::Logger;
 133
 134 use secp256k1::key::PublicKey;
 135
 136 use std::collections::hash_map::{self, HashMap};
 137 use std::ops::Deref;
 138 use std::sync::Mutex;
 139 use std::time::{Duration, SystemTime};
 140
 141 /// A utility for paying [`Invoice`]s and sending spontaneous payments.
 142 pub struct InvoicePayer<P: Deref, R, S: Deref, L: Deref, E>
 143 where
 144         P::Target: Payer,
 145         R: for <'a> Router<<<S as Deref>::Target as LockableScore<'a>>::Locked>,
 146         S::Target: for <'a> LockableScore<'a>,
 147         L::Target: Logger,
 148         E: EventHandler,
 149 {
 150         payer: P,
 151         router: R,
 152         scorer: S,
 153         logger: L,
 154         event_handler: E,
 155         /// Caches the overall attempts at making a payment, which is updated prior to retrying.
 156         payment_cache: Mutex<HashMap<PaymentHash, usize>>,
 157         retry_attempts: RetryAttempts,
 158 }
 159
 160 /// A trait defining behavior of an [`Invoice`] payer.
 161 pub trait Payer {
 162         /// Returns the payer's node id.
 163         fn node_id(&self) -> PublicKey;
 164
 165         /// Returns the payer's channels.
 166         fn first_hops(&self) -> Vec<ChannelDetails>;
 167
 168         /// Sends a payment over the Lightning Network using the given [`Route`].
 169         fn send_payment(
 170                 &self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>
 171         ) -> Result<PaymentId, PaymentSendFailure>;
 172
 173         /// Sends a spontaneous payment over the Lightning Network using the given [`Route`].
 174         fn send_spontaneous_payment(
 175                 &self, route: &Route, payment_preimage: PaymentPreimage
 176         ) -> Result<PaymentId, PaymentSendFailure>;
 177
 178         /// Retries a failed payment path for the [`PaymentId`] using the given [`Route`].
 179         fn retry_payment(&self, route: &Route, payment_id: PaymentId) -> Result<(), PaymentSendFailure>;
 180 }
 181
 182 /// A trait defining behavior for routing an [`Invoice`] payment.
 183 pub trait Router<S: Score> {
 184         /// Finds a [`Route`] between `payer` and `payee` for a payment with the given values.
 185         fn find_route(
 186                 &self, payer: &PublicKey, params: &RouteParameters, payment_hash: &PaymentHash,
 187                 first_hops: Option<&[&ChannelDetails]>, scorer: &S
 188         ) -> Result<Route, LightningError>;
 189 }
 190
 191 /// Number of attempts to retry payment path failures for an [`Invoice`].
 192 ///
 193 /// Note that this is the number of *path* failures, not full payment retries. For multi-path
 194 /// payments, if this is less than the total number of paths, we will never even retry all of the
 195 /// payment's paths.
 196 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
 197 pub struct RetryAttempts(pub usize);
 198
 199 /// An error that may occur when making a payment.
 200 #[derive(Clone, Debug)]
 201 pub enum PaymentError {
 202         /// An error resulting from the provided [`Invoice`] or payment hash.
 203         Invoice(&'static str),
 204         /// An error occurring when finding a route.
 205         Routing(LightningError),
 206         /// An error occurring when sending a payment.
 207         Sending(PaymentSendFailure),
 208 }
 209
 210 impl<P: Deref, R, S: Deref, L: Deref, E> InvoicePayer<P, R, S, L, E>
 211 where
 212         P::Target: Payer,
 213         R: for <'a> Router<<<S as Deref>::Target as LockableScore<'a>>::Locked>,
 214         S::Target: for <'a> LockableScore<'a>,
 215         L::Target: Logger,
 216         E: EventHandler,
 217 {
 218         /// Creates an invoice payer that retries failed payment paths.
 219         ///
 220         /// Will forward any [`Event::PaymentPathFailed`] events to the decorated `event_handler` once
 221         /// `retry_attempts` has been exceeded for a given [`Invoice`].
 222         pub fn new(
 223                 payer: P, router: R, scorer: S, logger: L, event_handler: E, retry_attempts: RetryAttempts
 224         ) -> Self {
 225                 Self {
 226                         payer,
 227                         router,
 228                         scorer,
 229                         logger,
 230                         event_handler,
 231                         payment_cache: Mutex::new(HashMap::new()),
 232                         retry_attempts,
 233                 }
 234         }
 235
 236         /// Pays the given [`Invoice`], caching it for later use in case a retry is needed.
 237         ///
 238         /// You should ensure that the `invoice.payment_hash()` is unique and the same payment_hash has
 239         /// never been paid before. Because [`InvoicePayer`] is stateless no effort is made to do so
 240         /// for you.
 241         pub fn pay_invoice(&self, invoice: &Invoice) -> Result<PaymentId, PaymentError> {
 242                 if invoice.amount_milli_satoshis().is_none() {
 243                         Err(PaymentError::Invoice("amount missing"))
 244                 } else {
 245                         self.pay_invoice_using_amount(invoice, None)
 246                 }
 247         }
 248
 249         /// Pays the given zero-value [`Invoice`] using the given amount, caching it for later use in
 250         /// case a retry is needed.
 251         ///
 252         /// You should ensure that the `invoice.payment_hash()` is unique and the same payment_hash has
 253         /// never been paid before. Because [`InvoicePayer`] is stateless no effort is made to do so
 254         /// for you.
 255         pub fn pay_zero_value_invoice(
 256                 &self, invoice: &Invoice, amount_msats: u64
 257         ) -> Result<PaymentId, PaymentError> {
 258                 if invoice.amount_milli_satoshis().is_some() {
 259                         Err(PaymentError::Invoice("amount unexpected"))
 260                 } else {
 261                         self.pay_invoice_using_amount(invoice, Some(amount_msats))
 262                 }
 263         }
 264
 265         fn pay_invoice_using_amount(
 266                 &self, invoice: &Invoice, amount_msats: Option<u64>
 267         ) -> Result<PaymentId, PaymentError> {
 268                 debug_assert!(invoice.amount_milli_satoshis().is_some() ^ amount_msats.is_some());
 269
 270                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 271                 match self.payment_cache.lock().unwrap().entry(payment_hash) {
 272                         hash_map::Entry::Occupied(_) => return Err(PaymentError::Invoice("payment pending")),
 273                         hash_map::Entry::Vacant(entry) => entry.insert(0),
 274                 };
 275
 276                 let payment_secret = Some(invoice.payment_secret().clone());
 277                 let mut payee = Payee::from_node_id(invoice.recover_payee_pub_key())
 278                         .with_expiry_time(expiry_time_from_unix_epoch(&invoice).as_secs())
 279                         .with_route_hints(invoice.route_hints());
 280                 if let Some(features) = invoice.features() {
 281                         payee = payee.with_features(features.clone());
 282                 }
 283                 let params = RouteParameters {
 284                         payee,
 285                         final_value_msat: invoice.amount_milli_satoshis().or(amount_msats).unwrap(),
 286                         final_cltv_expiry_delta: invoice.min_final_cltv_expiry() as u32,
 287                 };
 288
 289                 let send_payment = |route: &Route| {
 290                         self.payer.send_payment(route, payment_hash, &payment_secret)
 291                 };
 292                 self.pay_internal(&params, payment_hash, send_payment)
 293                         .map_err(|e| { self.payment_cache.lock().unwrap().remove(&payment_hash); e })
 294         }
 295
 296         /// Pays `pubkey` an amount using the hash of the given preimage, caching it for later use in
 297         /// case a retry is needed.
 298         ///
 299         /// You should ensure that `payment_preimage` is unique and that its `payment_hash` has never
 300         /// been paid before. Because [`InvoicePayer`] is stateless no effort is made to do so for you.
 301         pub fn pay_pubkey(
 302                 &self, pubkey: PublicKey, payment_preimage: PaymentPreimage, amount_msats: u64,
 303                 final_cltv_expiry_delta: u32
 304         ) -> Result<PaymentId, PaymentError> {
 305                 let payment_hash = PaymentHash(Sha256::hash(&payment_preimage.0).into_inner());
 306                 match self.payment_cache.lock().unwrap().entry(payment_hash) {
 307                         hash_map::Entry::Occupied(_) => return Err(PaymentError::Invoice("payment pending")),
 308                         hash_map::Entry::Vacant(entry) => entry.insert(0),
 309                 };
 310
 311                 let params = RouteParameters {
 312                         payee: Payee::for_keysend(pubkey),
 313                         final_value_msat: amount_msats,
 314                         final_cltv_expiry_delta,
 315                 };
 316
 317                 let send_payment = |route: &Route| {
 318                         self.payer.send_spontaneous_payment(route, payment_preimage)
 319                 };
 320                 self.pay_internal(&params, payment_hash, send_payment)
 321                         .map_err(|e| { self.payment_cache.lock().unwrap().remove(&payment_hash); e })
 322         }
 323
 324         fn pay_internal<F: FnOnce(&Route) -> Result<PaymentId, PaymentSendFailure> + Copy>(
 325                 &self, params: &RouteParameters, payment_hash: PaymentHash, send_payment: F,
 326         ) -> Result<PaymentId, PaymentError> {
 327                 if has_expired(params) {
 328                         log_trace!(self.logger, "Invoice expired prior to send for payment {}", log_bytes!(payment_hash.0));
 329                         return Err(PaymentError::Invoice("Invoice expired prior to send"));
 330                 }
 331
 332                 let payer = self.payer.node_id();
 333                 let first_hops = self.payer.first_hops();
 334                 let route = self.router.find_route(
 335                         &payer, params, &payment_hash, Some(&first_hops.iter().collect::<Vec<_>>()),
 336                         &self.scorer.lock()
 337                 ).map_err(|e| PaymentError::Routing(e))?;
 338
 339                 match send_payment(&route) {
 340                         Ok(payment_id) => Ok(payment_id),
 341                         Err(e) => match e {
 342                                 PaymentSendFailure::ParameterError(_) => Err(e),
 343                                 PaymentSendFailure::PathParameterError(_) => Err(e),
 344                                 PaymentSendFailure::AllFailedRetrySafe(_) => {
 345                                         let mut payment_cache = self.payment_cache.lock().unwrap();
 346                                         let retry_count = payment_cache.get_mut(&payment_hash).unwrap();
 347                                         if *retry_count >= self.retry_attempts.0 {
 348                                                 Err(e)
 349                                         } else {
 350                                                 *retry_count += 1;
 351                                                 std::mem::drop(payment_cache);
 352                                                 Ok(self.pay_internal(params, payment_hash, send_payment)?)
 353                                         }
 354                                 },
 355                                 PaymentSendFailure::PartialFailure { failed_paths_retry, payment_id, .. } => {
 356                                         if let Some(retry_data) = failed_paths_retry {
 357                                                 // Some paths were sent, even if we failed to send the full MPP value our
 358                                                 // recipient may misbehave and claim the funds, at which point we have to
 359                                                 // consider the payment sent, so return `Ok()` here, ignoring any retry
 360                                                 // errors.
 361                                                 let _ = self.retry_payment(payment_id, payment_hash, &retry_data);
 362                                                 Ok(payment_id)
 363                                         } else {
 364                                                 // This may happen if we send a payment and some paths fail, but
 365                                                 // only due to a temporary monitor failure or the like, implying
 366                                                 // they're really in-flight, but we haven't sent the initial
 367                                                 // HTLC-Add messages yet.
 368                                                 Ok(payment_id)
 369                                         }
 370                                 },
 371                         },
 372                 }.map_err(|e| PaymentError::Sending(e))
 373         }
 374
 375         fn retry_payment(
 376                 &self, payment_id: PaymentId, payment_hash: PaymentHash, params: &RouteParameters
 377         ) -> Result<(), ()> {
 378                 let max_payment_attempts = self.retry_attempts.0 + 1;
 379                 let attempts = *self.payment_cache.lock().unwrap()
 380                         .entry(payment_hash)
 381                         .and_modify(|attempts| *attempts += 1)
 382                         .or_insert(1);
 383
 384                 if attempts >= max_payment_attempts {
 385                         log_trace!(self.logger, "Payment {} exceeded maximum attempts; not retrying (attempts: {})", log_bytes!(payment_hash.0), attempts);
 386                         return Err(());
 387                 }
 388
 389                 if has_expired(params) {
 390                         log_trace!(self.logger, "Invoice expired for payment {}; not retrying (attempts: {})", log_bytes!(payment_hash.0), attempts);
 391                         return Err(());
 392                 }
 393
 394                 let payer = self.payer.node_id();
 395                 let first_hops = self.payer.first_hops();
 396                 let route = self.router.find_route(
 397                         &payer, &params, &payment_hash, Some(&first_hops.iter().collect::<Vec<_>>()),
 398                         &self.scorer.lock()
 399                 );
 400                 if route.is_err() {
 401                         log_trace!(self.logger, "Failed to find a route for payment {}; not retrying (attempts: {})", log_bytes!(payment_hash.0), attempts);
 402                         return Err(());
 403                 }
 404
 405                 match self.payer.retry_payment(&route.unwrap(), payment_id) {
 406                         Ok(()) => Ok(()),
 407                         Err(PaymentSendFailure::ParameterError(_)) |
 408                         Err(PaymentSendFailure::PathParameterError(_)) => {
 409                                 log_trace!(self.logger, "Failed to retry for payment {} due to bogus route/payment data, not retrying.", log_bytes!(payment_hash.0));
 410                                 Err(())
 411                         },
 412                         Err(PaymentSendFailure::AllFailedRetrySafe(_)) => {
 413                                 self.retry_payment(payment_id, payment_hash, params)
 414                         },
 415                         Err(PaymentSendFailure::PartialFailure { failed_paths_retry, .. }) => {
 416                                 if let Some(retry) = failed_paths_retry {
 417                                         // Always return Ok for the same reason as noted in pay_internal.
 418                                         let _ = self.retry_payment(payment_id, payment_hash, &retry);
 419                                 }
 420                                 Ok(())
 421                         },
 422                 }
 423         }
 424
 425         /// Removes the payment cached by the given payment hash.
 426         ///
 427         /// Should be called once a payment has failed or succeeded if not using [`InvoicePayer`] as an
 428         /// [`EventHandler`]. Otherwise, calling this method is unnecessary.
 429         pub fn remove_cached_payment(&self, payment_hash: &PaymentHash) {
 430                 self.payment_cache.lock().unwrap().remove(payment_hash);
 431         }
 432 }
 433
 434 fn expiry_time_from_unix_epoch(invoice: &Invoice) -> Duration {
 435         invoice.timestamp().duration_since(SystemTime::UNIX_EPOCH).unwrap() + invoice.expiry_time()
 436 }
 437
 438 fn has_expired(params: &RouteParameters) -> bool {
 439         if let Some(expiry_time) = params.payee.expiry_time {
 440                 Invoice::is_expired_from_epoch(&SystemTime::UNIX_EPOCH, Duration::from_secs(expiry_time))
 441         } else { false }
 442 }
 443
 444 impl<P: Deref, R, S: Deref, L: Deref, E> EventHandler for InvoicePayer<P, R, S, L, E>
 445 where
 446         P::Target: Payer,
 447         R: for <'a> Router<<<S as Deref>::Target as LockableScore<'a>>::Locked>,
 448         S::Target: for <'a> LockableScore<'a>,
 449         L::Target: Logger,
 450         E: EventHandler,
 451 {
 452         fn handle_event(&self, event: &Event) {
 453                 match event {
 454                         Event::PaymentPathFailed {
 455                                 all_paths_failed, payment_id, payment_hash, rejected_by_dest, path,
 456                                 short_channel_id, retry, ..
 457                         } => {
 458                                 if let Some(short_channel_id) = short_channel_id {
 459                                         let path = path.iter().collect::<Vec<_>>();
 460                                         self.scorer.lock().payment_path_failed(&path, *short_channel_id);
 461                                 }
 462
 463                                 if *rejected_by_dest {
 464                                         log_trace!(self.logger, "Payment {} rejected by destination; not retrying", log_bytes!(payment_hash.0));
 465                                 } else if payment_id.is_none() {
 466                                         log_trace!(self.logger, "Payment {} has no id; not retrying", log_bytes!(payment_hash.0));
 467                                 } else if retry.is_none() {
 468                                         log_trace!(self.logger, "Payment {} missing retry params; not retrying", log_bytes!(payment_hash.0));
 469                                 } else if self.retry_payment(payment_id.unwrap(), *payment_hash, retry.as_ref().unwrap()).is_ok() {
 470                                         // We retried at least somewhat, don't provide the PaymentPathFailed event to the user.
 471                                         return;
 472                                 }
 473
 474                                 if *all_paths_failed { self.payment_cache.lock().unwrap().remove(payment_hash); }
 475                         },
 476                         Event::PaymentSent { payment_hash, .. } => {
 477                                 let mut payment_cache = self.payment_cache.lock().unwrap();
 478                                 let attempts = payment_cache
 479                                         .remove(payment_hash)
 480                                         .map_or(1, |attempts| attempts + 1);
 481                                 log_trace!(self.logger, "Payment {} succeeded (attempts: {})", log_bytes!(payment_hash.0), attempts);
 482                         },
 483                         _ => {},
 484                 }
 485
 486                 // Delegate to the decorated event handler unless the payment is retried.
 487                 self.event_handler.handle_event(event)
 488         }
 489 }
 490
 491 #[cfg(test)]
 492 mod tests {
 493         use super::*;
 494         use crate::{DEFAULT_EXPIRY_TIME, InvoiceBuilder, Currency};
 495         use utils::create_invoice_from_channelmanager;
 496         use bitcoin_hashes::sha256::Hash as Sha256;
 497         use lightning::ln::PaymentPreimage;
 498         use lightning::ln::features::{ChannelFeatures, NodeFeatures, InitFeatures};
 499         use lightning::ln::functional_test_utils::*;
 500         use lightning::ln::msgs::{ErrorAction, LightningError};
 501         use lightning::routing::network_graph::NodeId;
 502         use lightning::routing::router::{Payee, Route, RouteHop};
 503         use lightning::util::test_utils::TestLogger;
 504         use lightning::util::errors::APIError;
 505         use lightning::util::events::{Event, MessageSendEventsProvider};
 506         use secp256k1::{SecretKey, PublicKey, Secp256k1};
 507         use std::cell::RefCell;
 508         use std::collections::VecDeque;
 509         use std::time::{SystemTime, Duration};
 510
 511         fn invoice(payment_preimage: PaymentPreimage) -> Invoice {
 512                 let payment_hash = Sha256::hash(&payment_preimage.0);
 513                 let private_key = SecretKey::from_slice(&[42; 32]).unwrap();
 514                 InvoiceBuilder::new(Currency::Bitcoin)
 515                         .description("test".into())
 516                         .payment_hash(payment_hash)
 517                         .payment_secret(PaymentSecret([0; 32]))
 518                         .current_timestamp()
 519                         .min_final_cltv_expiry(144)
 520                         .amount_milli_satoshis(128)
 521                         .build_signed(|hash| {
 522                                 Secp256k1::new().sign_recoverable(hash, &private_key)
 523                         })
 524                         .unwrap()
 525         }
 526
 527         fn zero_value_invoice(payment_preimage: PaymentPreimage) -> Invoice {
 528                 let payment_hash = Sha256::hash(&payment_preimage.0);
 529                 let private_key = SecretKey::from_slice(&[42; 32]).unwrap();
 530                 InvoiceBuilder::new(Currency::Bitcoin)
 531                         .description("test".into())
 532                         .payment_hash(payment_hash)
 533                         .payment_secret(PaymentSecret([0; 32]))
 534                         .current_timestamp()
 535                         .min_final_cltv_expiry(144)
 536                         .build_signed(|hash| {
 537                                 Secp256k1::new().sign_recoverable(hash, &private_key)
 538                         })
 539                         .unwrap()
 540         }
 541
 542         fn expired_invoice(payment_preimage: PaymentPreimage) -> Invoice {
 543                 let payment_hash = Sha256::hash(&payment_preimage.0);
 544                 let private_key = SecretKey::from_slice(&[42; 32]).unwrap();
 545                 let timestamp = SystemTime::now()
 546                         .checked_sub(Duration::from_secs(DEFAULT_EXPIRY_TIME * 2))
 547                         .unwrap();
 548                 InvoiceBuilder::new(Currency::Bitcoin)
 549                         .description("test".into())
 550                         .payment_hash(payment_hash)
 551                         .payment_secret(PaymentSecret([0; 32]))
 552                         .timestamp(timestamp)
 553                         .min_final_cltv_expiry(144)
 554                         .amount_milli_satoshis(128)
 555                         .build_signed(|hash| {
 556                                 Secp256k1::new().sign_recoverable(hash, &private_key)
 557                         })
 558                         .unwrap()
 559         }
 560
 561         fn pubkey() -> PublicKey {
 562                 PublicKey::from_slice(&hex::decode("02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619").unwrap()[..]).unwrap()
 563         }
 564
 565         #[test]
 566         fn pays_invoice_on_first_attempt() {
 567                 let event_handled = core::cell::RefCell::new(false);
 568                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 569
 570                 let payment_preimage = PaymentPreimage([1; 32]);
 571                 let invoice = invoice(payment_preimage);
 572                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 573                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 574
 575                 let payer = TestPayer::new().expect_send(Amount::ForInvoice(final_value_msat));
 576                 let router = TestRouter {};
 577                 let scorer = RefCell::new(TestScorer::new());
 578                 let logger = TestLogger::new();
 579                 let invoice_payer =
 580                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(0));
 581
 582                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 583                 assert_eq!(*payer.attempts.borrow(), 1);
 584
 585                 invoice_payer.handle_event(&Event::PaymentSent {
 586                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
 587                 });
 588                 assert_eq!(*event_handled.borrow(), true);
 589                 assert_eq!(*payer.attempts.borrow(), 1);
 590         }
 591
 592         #[test]
 593         fn pays_invoice_on_retry() {
 594                 let event_handled = core::cell::RefCell::new(false);
 595                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 596
 597                 let payment_preimage = PaymentPreimage([1; 32]);
 598                 let invoice = invoice(payment_preimage);
 599                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 600                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 601
 602                 let payer = TestPayer::new()
 603                         .expect_send(Amount::ForInvoice(final_value_msat))
 604                         .expect_send(Amount::OnRetry(final_value_msat / 2));
 605                 let router = TestRouter {};
 606                 let scorer = RefCell::new(TestScorer::new());
 607                 let logger = TestLogger::new();
 608                 let invoice_payer =
 609                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 610
 611                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 612                 assert_eq!(*payer.attempts.borrow(), 1);
 613
 614                 let event = Event::PaymentPathFailed {
 615                         payment_id,
 616                         payment_hash,
 617                         network_update: None,
 618                         rejected_by_dest: false,
 619                         all_paths_failed: false,
 620                         path: TestRouter::path_for_value(final_value_msat),
 621                         short_channel_id: None,
 622                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 623                 };
 624                 invoice_payer.handle_event(&event);
 625                 assert_eq!(*event_handled.borrow(), false);
 626                 assert_eq!(*payer.attempts.borrow(), 2);
 627
 628                 invoice_payer.handle_event(&Event::PaymentSent {
 629                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
 630                 });
 631                 assert_eq!(*event_handled.borrow(), true);
 632                 assert_eq!(*payer.attempts.borrow(), 2);
 633         }
 634
 635         #[test]
 636         fn pays_invoice_on_partial_failure() {
 637                 let event_handler = |_: &_| { panic!() };
 638
 639                 let payment_preimage = PaymentPreimage([1; 32]);
 640                 let invoice = invoice(payment_preimage);
 641                 let retry = TestRouter::retry_for_invoice(&invoice);
 642                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 643
 644                 let payer = TestPayer::new()
 645                         .fails_with_partial_failure(retry.clone(), OnAttempt(1))
 646                         .fails_with_partial_failure(retry, OnAttempt(2))
 647                         .expect_send(Amount::ForInvoice(final_value_msat))
 648                         .expect_send(Amount::OnRetry(final_value_msat / 2))
 649                         .expect_send(Amount::OnRetry(final_value_msat / 2));
 650                 let router = TestRouter {};
 651                 let scorer = RefCell::new(TestScorer::new());
 652                 let logger = TestLogger::new();
 653                 let invoice_payer =
 654                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 655
 656                 assert!(invoice_payer.pay_invoice(&invoice).is_ok());
 657         }
 658
 659         #[test]
 660         fn retries_payment_path_for_unknown_payment() {
 661                 let event_handled = core::cell::RefCell::new(false);
 662                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 663
 664                 let payment_preimage = PaymentPreimage([1; 32]);
 665                 let invoice = invoice(payment_preimage);
 666                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 667                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 668
 669                 let payer = TestPayer::new()
 670                         .expect_send(Amount::OnRetry(final_value_msat / 2))
 671                         .expect_send(Amount::OnRetry(final_value_msat / 2));
 672                 let router = TestRouter {};
 673                 let scorer = RefCell::new(TestScorer::new());
 674                 let logger = TestLogger::new();
 675                 let invoice_payer =
 676                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 677
 678                 let payment_id = Some(PaymentId([1; 32]));
 679                 let event = Event::PaymentPathFailed {
 680                         payment_id,
 681                         payment_hash,
 682                         network_update: None,
 683                         rejected_by_dest: false,
 684                         all_paths_failed: false,
 685                         path: TestRouter::path_for_value(final_value_msat),
 686                         short_channel_id: None,
 687                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 688                 };
 689                 invoice_payer.handle_event(&event);
 690                 assert_eq!(*event_handled.borrow(), false);
 691                 assert_eq!(*payer.attempts.borrow(), 1);
 692
 693                 invoice_payer.handle_event(&event);
 694                 assert_eq!(*event_handled.borrow(), false);
 695                 assert_eq!(*payer.attempts.borrow(), 2);
 696
 697                 invoice_payer.handle_event(&Event::PaymentSent {
 698                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
 699                 });
 700                 assert_eq!(*event_handled.borrow(), true);
 701                 assert_eq!(*payer.attempts.borrow(), 2);
 702         }
 703
 704         #[test]
 705         fn fails_paying_invoice_after_max_retries() {
 706                 let event_handled = core::cell::RefCell::new(false);
 707                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 708
 709                 let payment_preimage = PaymentPreimage([1; 32]);
 710                 let invoice = invoice(payment_preimage);
 711                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 712
 713                 let payer = TestPayer::new()
 714                         .expect_send(Amount::ForInvoice(final_value_msat))
 715                         .expect_send(Amount::OnRetry(final_value_msat / 2))
 716                         .expect_send(Amount::OnRetry(final_value_msat / 2));
 717                 let router = TestRouter {};
 718                 let scorer = RefCell::new(TestScorer::new());
 719                 let logger = TestLogger::new();
 720                 let invoice_payer =
 721                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 722
 723                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 724                 assert_eq!(*payer.attempts.borrow(), 1);
 725
 726                 let event = Event::PaymentPathFailed {
 727                         payment_id,
 728                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 729                         network_update: None,
 730                         rejected_by_dest: false,
 731                         all_paths_failed: true,
 732                         path: TestRouter::path_for_value(final_value_msat),
 733                         short_channel_id: None,
 734                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 735                 };
 736                 invoice_payer.handle_event(&event);
 737                 assert_eq!(*event_handled.borrow(), false);
 738                 assert_eq!(*payer.attempts.borrow(), 2);
 739
 740                 let event = Event::PaymentPathFailed {
 741                         payment_id,
 742                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 743                         network_update: None,
 744                         rejected_by_dest: false,
 745                         all_paths_failed: false,
 746                         path: TestRouter::path_for_value(final_value_msat / 2),
 747                         short_channel_id: None,
 748                         retry: Some(RouteParameters {
 749                                 final_value_msat: final_value_msat / 2, ..TestRouter::retry_for_invoice(&invoice)
 750                         }),
 751                 };
 752                 invoice_payer.handle_event(&event);
 753                 assert_eq!(*event_handled.borrow(), false);
 754                 assert_eq!(*payer.attempts.borrow(), 3);
 755
 756                 invoice_payer.handle_event(&event);
 757                 assert_eq!(*event_handled.borrow(), true);
 758                 assert_eq!(*payer.attempts.borrow(), 3);
 759         }
 760
 761         #[test]
 762         fn fails_paying_invoice_with_missing_retry_params() {
 763                 let event_handled = core::cell::RefCell::new(false);
 764                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 765
 766                 let payment_preimage = PaymentPreimage([1; 32]);
 767                 let invoice = invoice(payment_preimage);
 768                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 769
 770                 let payer = TestPayer::new().expect_send(Amount::ForInvoice(final_value_msat));
 771                 let router = TestRouter {};
 772                 let scorer = RefCell::new(TestScorer::new());
 773                 let logger = TestLogger::new();
 774                 let invoice_payer =
 775                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 776
 777                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 778                 assert_eq!(*payer.attempts.borrow(), 1);
 779
 780                 let event = Event::PaymentPathFailed {
 781                         payment_id,
 782                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 783                         network_update: None,
 784                         rejected_by_dest: false,
 785                         all_paths_failed: false,
 786                         path: vec![],
 787                         short_channel_id: None,
 788                         retry: None,
 789                 };
 790                 invoice_payer.handle_event(&event);
 791                 assert_eq!(*event_handled.borrow(), true);
 792                 assert_eq!(*payer.attempts.borrow(), 1);
 793         }
 794
 795         #[test]
 796         fn fails_paying_invoice_after_expiration() {
 797                 let event_handled = core::cell::RefCell::new(false);
 798                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 799
 800                 let payer = TestPayer::new();
 801                 let router = TestRouter {};
 802                 let scorer = RefCell::new(TestScorer::new());
 803                 let logger = TestLogger::new();
 804                 let invoice_payer =
 805                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 806
 807                 let payment_preimage = PaymentPreimage([1; 32]);
 808                 let invoice = expired_invoice(payment_preimage);
 809                 if let PaymentError::Invoice(msg) = invoice_payer.pay_invoice(&invoice).unwrap_err() {
 810                         assert_eq!(msg, "Invoice expired prior to send");
 811                 } else { panic!("Expected Invoice Error"); }
 812         }
 813
 814         #[test]
 815         fn fails_retrying_invoice_after_expiration() {
 816                 let event_handled = core::cell::RefCell::new(false);
 817                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 818
 819                 let payment_preimage = PaymentPreimage([1; 32]);
 820                 let invoice = invoice(payment_preimage);
 821                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 822
 823                 let payer = TestPayer::new().expect_send(Amount::ForInvoice(final_value_msat));
 824                 let router = TestRouter {};
 825                 let scorer = RefCell::new(TestScorer::new());
 826                 let logger = TestLogger::new();
 827                 let invoice_payer =
 828                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 829
 830                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 831                 assert_eq!(*payer.attempts.borrow(), 1);
 832
 833                 let mut retry_data = TestRouter::retry_for_invoice(&invoice);
 834                 retry_data.payee.expiry_time = Some(SystemTime::now()
 835                         .checked_sub(Duration::from_secs(2)).unwrap()
 836                         .duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs());
 837                 let event = Event::PaymentPathFailed {
 838                         payment_id,
 839                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 840                         network_update: None,
 841                         rejected_by_dest: false,
 842                         all_paths_failed: false,
 843                         path: vec![],
 844                         short_channel_id: None,
 845                         retry: Some(retry_data),
 846                 };
 847                 invoice_payer.handle_event(&event);
 848                 assert_eq!(*event_handled.borrow(), true);
 849                 assert_eq!(*payer.attempts.borrow(), 1);
 850         }
 851
 852         #[test]
 853         fn fails_paying_invoice_after_retry_error() {
 854                 let event_handled = core::cell::RefCell::new(false);
 855                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 856
 857                 let payment_preimage = PaymentPreimage([1; 32]);
 858                 let invoice = invoice(payment_preimage);
 859                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 860
 861                 let payer = TestPayer::new()
 862                         .fails_on_attempt(2)
 863                         .expect_send(Amount::ForInvoice(final_value_msat))
 864                         .expect_send(Amount::OnRetry(final_value_msat / 2));
 865                 let router = TestRouter {};
 866                 let scorer = RefCell::new(TestScorer::new());
 867                 let logger = TestLogger::new();
 868                 let invoice_payer =
 869                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 870
 871                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 872                 assert_eq!(*payer.attempts.borrow(), 1);
 873
 874                 let event = Event::PaymentPathFailed {
 875                         payment_id,
 876                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 877                         network_update: None,
 878                         rejected_by_dest: false,
 879                         all_paths_failed: false,
 880                         path: TestRouter::path_for_value(final_value_msat / 2),
 881                         short_channel_id: None,
 882                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 883                 };
 884                 invoice_payer.handle_event(&event);
 885                 assert_eq!(*event_handled.borrow(), true);
 886                 assert_eq!(*payer.attempts.borrow(), 2);
 887         }
 888
 889         #[test]
 890         fn fails_paying_invoice_after_rejected_by_payee() {
 891                 let event_handled = core::cell::RefCell::new(false);
 892                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 893
 894                 let payment_preimage = PaymentPreimage([1; 32]);
 895                 let invoice = invoice(payment_preimage);
 896                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 897
 898                 let payer = TestPayer::new().expect_send(Amount::ForInvoice(final_value_msat));
 899                 let router = TestRouter {};
 900                 let scorer = RefCell::new(TestScorer::new());
 901                 let logger = TestLogger::new();
 902                 let invoice_payer =
 903                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 904
 905                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 906                 assert_eq!(*payer.attempts.borrow(), 1);
 907
 908                 let event = Event::PaymentPathFailed {
 909                         payment_id,
 910                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 911                         network_update: None,
 912                         rejected_by_dest: true,
 913                         all_paths_failed: false,
 914                         path: vec![],
 915                         short_channel_id: None,
 916                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 917                 };
 918                 invoice_payer.handle_event(&event);
 919                 assert_eq!(*event_handled.borrow(), true);
 920                 assert_eq!(*payer.attempts.borrow(), 1);
 921         }
 922
 923         #[test]
 924         fn fails_repaying_invoice_with_pending_payment() {
 925                 let event_handled = core::cell::RefCell::new(false);
 926                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 927
 928                 let payment_preimage = PaymentPreimage([1; 32]);
 929                 let invoice = invoice(payment_preimage);
 930                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 931
 932                 let payer = TestPayer::new()
 933                         .expect_send(Amount::ForInvoice(final_value_msat))
 934                         .expect_send(Amount::ForInvoice(final_value_msat));
 935                 let router = TestRouter {};
 936                 let scorer = RefCell::new(TestScorer::new());
 937                 let logger = TestLogger::new();
 938                 let invoice_payer =
 939                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(0));
 940
 941                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 942
 943                 // Cannot repay an invoice pending payment.
 944                 match invoice_payer.pay_invoice(&invoice) {
 945                         Err(PaymentError::Invoice("payment pending")) => {},
 946                         Err(_) => panic!("unexpected error"),
 947                         Ok(_) => panic!("expected invoice error"),
 948                 }
 949
 950                 // Can repay an invoice once cleared from cache.
 951                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 952                 invoice_payer.remove_cached_payment(&payment_hash);
 953                 assert!(invoice_payer.pay_invoice(&invoice).is_ok());
 954
 955                 // Cannot retry paying an invoice if cleared from cache.
 956                 invoice_payer.remove_cached_payment(&payment_hash);
 957                 let event = Event::PaymentPathFailed {
 958                         payment_id,
 959                         payment_hash,
 960                         network_update: None,
 961                         rejected_by_dest: false,
 962                         all_paths_failed: false,
 963                         path: vec![],
 964                         short_channel_id: None,
 965                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 966                 };
 967                 invoice_payer.handle_event(&event);
 968                 assert_eq!(*event_handled.borrow(), true);
 969         }
 970
 971         #[test]
 972         fn fails_paying_invoice_with_routing_errors() {
 973                 let payer = TestPayer::new();
 974                 let router = FailingRouter {};
 975                 let scorer = RefCell::new(TestScorer::new());
 976                 let logger = TestLogger::new();
 977                 let invoice_payer =
 978                         InvoicePayer::new(&payer, router, &scorer, &logger, |_: &_| {}, RetryAttempts(0));
 979
 980                 let payment_preimage = PaymentPreimage([1; 32]);
 981                 let invoice = invoice(payment_preimage);
 982                 match invoice_payer.pay_invoice(&invoice) {
 983                         Err(PaymentError::Routing(_)) => {},
 984                         Err(_) => panic!("unexpected error"),
 985                         Ok(_) => panic!("expected routing error"),
 986                 }
 987         }
 988
 989         #[test]
 990         fn fails_paying_invoice_with_sending_errors() {
 991                 let payment_preimage = PaymentPreimage([1; 32]);
 992                 let invoice = invoice(payment_preimage);
 993                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 994
 995                 let payer = TestPayer::new()
 996                         .fails_on_attempt(1)
 997                         .expect_send(Amount::ForInvoice(final_value_msat));
 998                 let router = TestRouter {};
 999                 let scorer = RefCell::new(TestScorer::new());
1000                 let logger = TestLogger::new();
1001                 let invoice_payer =
1002                         InvoicePayer::new(&payer, router, &scorer, &logger, |_: &_| {}, RetryAttempts(0));
1003
1004                 match invoice_payer.pay_invoice(&invoice) {
1005                         Err(PaymentError::Sending(_)) => {},
1006                         Err(_) => panic!("unexpected error"),
1007                         Ok(_) => panic!("expected sending error"),
1008                 }
1009         }
1010
1011         #[test]
1012         fn pays_zero_value_invoice_using_amount() {
1013                 let event_handled = core::cell::RefCell::new(false);
1014                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1015
1016                 let payment_preimage = PaymentPreimage([1; 32]);
1017                 let invoice = zero_value_invoice(payment_preimage);
1018                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
1019                 let final_value_msat = 100;
1020
1021                 let payer = TestPayer::new().expect_send(Amount::ForInvoice(final_value_msat));
1022                 let router = TestRouter {};
1023                 let scorer = RefCell::new(TestScorer::new());
1024                 let logger = TestLogger::new();
1025                 let invoice_payer =
1026                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(0));
1027
1028                 let payment_id =
1029                         Some(invoice_payer.pay_zero_value_invoice(&invoice, final_value_msat).unwrap());
1030                 assert_eq!(*payer.attempts.borrow(), 1);
1031
1032                 invoice_payer.handle_event(&Event::PaymentSent {
1033                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
1034                 });
1035                 assert_eq!(*event_handled.borrow(), true);
1036                 assert_eq!(*payer.attempts.borrow(), 1);
1037         }
1038
1039         #[test]
1040         fn fails_paying_zero_value_invoice_with_amount() {
1041                 let event_handled = core::cell::RefCell::new(false);
1042                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1043
1044                 let payer = TestPayer::new();
1045                 let router = TestRouter {};
1046                 let scorer = RefCell::new(TestScorer::new());
1047                 let logger = TestLogger::new();
1048                 let invoice_payer =
1049                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(0));
1050
1051                 let payment_preimage = PaymentPreimage([1; 32]);
1052                 let invoice = invoice(payment_preimage);
1053
1054                 // Cannot repay an invoice pending payment.
1055                 match invoice_payer.pay_zero_value_invoice(&invoice, 100) {
1056                         Err(PaymentError::Invoice("amount unexpected")) => {},
1057                         Err(_) => panic!("unexpected error"),
1058                         Ok(_) => panic!("expected invoice error"),
1059                 }
1060         }
1061
1062         #[test]
1063         fn pays_pubkey_with_amount() {
1064                 let event_handled = core::cell::RefCell::new(false);
1065                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1066
1067                 let pubkey = pubkey();
1068                 let payment_preimage = PaymentPreimage([1; 32]);
1069                 let payment_hash = PaymentHash(Sha256::hash(&payment_preimage.0).into_inner());
1070                 let final_value_msat = 100;
1071                 let final_cltv_expiry_delta = 42;
1072
1073                 let payer = TestPayer::new()
1074                         .expect_send(Amount::Spontaneous(final_value_msat))
1075                         .expect_send(Amount::OnRetry(final_value_msat));
1076                 let router = TestRouter {};
1077                 let scorer = RefCell::new(TestScorer::new());
1078                 let logger = TestLogger::new();
1079                 let invoice_payer =
1080                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
1081
1082                 let payment_id = Some(invoice_payer.pay_pubkey(
1083                                 pubkey, payment_preimage, final_value_msat, final_cltv_expiry_delta
1084                         ).unwrap());
1085                 assert_eq!(*payer.attempts.borrow(), 1);
1086
1087                 let retry = RouteParameters {
1088                         payee: Payee::for_keysend(pubkey),
1089                         final_value_msat,
1090                         final_cltv_expiry_delta,
1091                 };
1092                 let event = Event::PaymentPathFailed {
1093                         payment_id,
1094                         payment_hash,
1095                         network_update: None,
1096                         rejected_by_dest: false,
1097                         all_paths_failed: false,
1098                         path: vec![],
1099                         short_channel_id: None,
1100                         retry: Some(retry),
1101                 };
1102                 invoice_payer.handle_event(&event);
1103                 assert_eq!(*event_handled.borrow(), false);
1104                 assert_eq!(*payer.attempts.borrow(), 2);
1105
1106                 invoice_payer.handle_event(&Event::PaymentSent {
1107                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
1108                 });
1109                 assert_eq!(*event_handled.borrow(), true);
1110                 assert_eq!(*payer.attempts.borrow(), 2);
1111         }
1112
1113         #[test]
1114         fn scores_failed_channel() {
1115                 let event_handled = core::cell::RefCell::new(false);
1116                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1117
1118                 let payment_preimage = PaymentPreimage([1; 32]);
1119                 let invoice = invoice(payment_preimage);
1120                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
1121                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
1122                 let path = TestRouter::path_for_value(final_value_msat);
1123                 let short_channel_id = Some(path[0].short_channel_id);
1124
1125                 // Expect that scorer is given short_channel_id upon handling the event.
1126                 let payer = TestPayer::new()
1127                         .expect_send(Amount::ForInvoice(final_value_msat))
1128                         .expect_send(Amount::OnRetry(final_value_msat / 2));
1129                 let router = TestRouter {};
1130                 let scorer = RefCell::new(TestScorer::new().expect_channel_failure(short_channel_id.unwrap()));
1131                 let logger = TestLogger::new();
1132                 let invoice_payer =
1133                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
1134
1135                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
1136                 let event = Event::PaymentPathFailed {
1137                         payment_id,
1138                         payment_hash,
1139                         network_update: None,
1140                         rejected_by_dest: false,
1141                         all_paths_failed: false,
1142                         path,
1143                         short_channel_id,
1144                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
1145                 };
1146                 invoice_payer.handle_event(&event);
1147         }
1148
1149         struct TestRouter;
1150
1151         impl TestRouter {
1152                 fn route_for_value(final_value_msat: u64) -> Route {
1153                         Route {
1154                                 paths: vec![
1155                                         vec![RouteHop {
1156                                                 pubkey: PublicKey::from_slice(&hex::decode("02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619").unwrap()[..]).unwrap(),
1157                                                 channel_features: ChannelFeatures::empty(),
1158                                                 node_features: NodeFeatures::empty(),
1159                                                 short_channel_id: 0, fee_msat: final_value_msat / 2, cltv_expiry_delta: 144
1160                                         }],
1161                                         vec![RouteHop {
1162                                                 pubkey: PublicKey::from_slice(&hex::decode("0324653eac434488002cc06bbfb7f10fe18991e35f9fe4302dbea6d2353dc0ab1c").unwrap()[..]).unwrap(),
1163                                                 channel_features: ChannelFeatures::empty(),
1164                                                 node_features: NodeFeatures::empty(),
1165                                                 short_channel_id: 1, fee_msat: final_value_msat / 2, cltv_expiry_delta: 144
1166                                         }],
1167                                 ],
1168                                 payee: None,
1169                         }
1170                 }
1171
1172                 fn path_for_value(final_value_msat: u64) -> Vec<RouteHop> {
1173                         TestRouter::route_for_value(final_value_msat).paths[0].clone()
1174                 }
1175
1176                 fn retry_for_invoice(invoice: &Invoice) -> RouteParameters {
1177                         let mut payee = Payee::from_node_id(invoice.recover_payee_pub_key())
1178                                 .with_expiry_time(expiry_time_from_unix_epoch(invoice).as_secs())
1179                                 .with_route_hints(invoice.route_hints());
1180                         if let Some(features) = invoice.features() {
1181                                 payee = payee.with_features(features.clone());
1182                         }
1183                         let final_value_msat = invoice.amount_milli_satoshis().unwrap() / 2;
1184                         RouteParameters {
1185                                 payee,
1186                                 final_value_msat,
1187                                 final_cltv_expiry_delta: invoice.min_final_cltv_expiry() as u32,
1188                         }
1189                 }
1190         }
1191
1192         impl<S: Score> Router<S> for TestRouter {
1193                 fn find_route(
1194                         &self, _payer: &PublicKey, params: &RouteParameters, _payment_hash: &PaymentHash,
1195                         _first_hops: Option<&[&ChannelDetails]>, _scorer: &S
1196                 ) -> Result<Route, LightningError> {
1197                         Ok(Route {
1198                                 payee: Some(params.payee.clone()), ..Self::route_for_value(params.final_value_msat)
1199                         })
1200                 }
1201         }
1202
1203         struct FailingRouter;
1204
1205         impl<S: Score> Router<S> for FailingRouter {
1206                 fn find_route(
1207                         &self, _payer: &PublicKey, _params: &RouteParameters, _payment_hash: &PaymentHash,
1208                         _first_hops: Option<&[&ChannelDetails]>, _scorer: &S
1209                 ) -> Result<Route, LightningError> {
1210                         Err(LightningError { err: String::new(), action: ErrorAction::IgnoreError })
1211                 }
1212         }
1213
1214         struct TestScorer {
1215                 expectations: VecDeque<u64>,
1216         }
1217
1218         impl TestScorer {
1219                 fn new() -> Self {
1220                         Self {
1221                                 expectations: VecDeque::new(),
1222                         }
1223                 }
1224
1225                 fn expect_channel_failure(mut self, short_channel_id: u64) -> Self {
1226                         self.expectations.push_back(short_channel_id);
1227                         self
1228                 }
1229         }
1230
1231         #[cfg(c_bindings)]
1232         impl lightning::util::ser::Writeable for TestScorer {
1233                 fn write<W: lightning::util::ser::Writer>(&self, _: &mut W) -> Result<(), std::io::Error> { unreachable!(); }
1234         }
1235         impl Score for TestScorer {
1236                 fn channel_penalty_msat(
1237                         &self, _short_channel_id: u64, _send_amt: u64, _chan_amt: Option<u64>, _source: &NodeId, _target: &NodeId
1238                 ) -> u64 { 0 }
1239
1240                 fn payment_path_failed(&mut self, _path: &[&RouteHop], short_channel_id: u64) {
1241                         if let Some(expected_short_channel_id) = self.expectations.pop_front() {
1242                                 assert_eq!(short_channel_id, expected_short_channel_id);
1243                         }
1244                 }
1245         }
1246
1247         impl Drop for TestScorer {
1248                 fn drop(&mut self) {
1249                         if std::thread::panicking() {
1250                                 return;
1251                         }
1252
1253                         if !self.expectations.is_empty() {
1254                                 panic!("Unsatisfied channel failure expectations: {:?}", self.expectations);
1255                         }
1256                 }
1257         }
1258
1259         struct TestPayer {
1260                 expectations: core::cell::RefCell<VecDeque<Amount>>,
1261                 attempts: core::cell::RefCell<usize>,
1262                 failing_on_attempt: core::cell::RefCell<HashMap<usize, PaymentSendFailure>>,
1263         }
1264
1265         #[derive(Clone, Debug, PartialEq, Eq)]
1266         enum Amount {
1267                 ForInvoice(u64),
1268                 Spontaneous(u64),
1269                 OnRetry(u64),
1270         }
1271
1272         struct OnAttempt(usize);
1273
1274         impl TestPayer {
1275                 fn new() -> Self {
1276                         Self {
1277                                 expectations: core::cell::RefCell::new(VecDeque::new()),
1278                                 attempts: core::cell::RefCell::new(0),
1279                                 failing_on_attempt: core::cell::RefCell::new(HashMap::new()),
1280                         }
1281                 }
1282
1283                 fn expect_send(self, value_msat: Amount) -> Self {
1284                         self.expectations.borrow_mut().push_back(value_msat);
1285                         self
1286                 }
1287
1288                 fn fails_on_attempt(self, attempt: usize) -> Self {
1289                         let failure = PaymentSendFailure::ParameterError(APIError::MonitorUpdateFailed);
1290                         self.fails_with(failure, OnAttempt(attempt))
1291                 }
1292
1293                 fn fails_with_partial_failure(self, retry: RouteParameters, attempt: OnAttempt) -> Self {
1294                         self.fails_with(PaymentSendFailure::PartialFailure {
1295                                 results: vec![],
1296                                 failed_paths_retry: Some(retry),
1297                                 payment_id: PaymentId([1; 32]),
1298                         }, attempt)
1299                 }
1300
1301                 fn fails_with(self, failure: PaymentSendFailure, attempt: OnAttempt) -> Self {
1302                         self.failing_on_attempt.borrow_mut().insert(attempt.0, failure);
1303                         self
1304                 }
1305
1306                 fn check_attempts(&self) -> Result<PaymentId, PaymentSendFailure> {
1307                         let mut attempts = self.attempts.borrow_mut();
1308                         *attempts += 1;
1309
1310                         match self.failing_on_attempt.borrow_mut().remove(&*attempts) {
1311                                 Some(failure) => Err(failure),
1312                                 None => Ok(PaymentId([1; 32])),
1313                         }
1314                 }
1315
1316                 fn check_value_msats(&self, actual_value_msats: Amount) {
1317                         let expected_value_msats = self.expectations.borrow_mut().pop_front();
1318                         if let Some(expected_value_msats) = expected_value_msats {
1319                                 assert_eq!(actual_value_msats, expected_value_msats);
1320                         } else {
1321                                 panic!("Unexpected amount: {:?}", actual_value_msats);
1322                         }
1323                 }
1324         }
1325
1326         impl Drop for TestPayer {
1327                 fn drop(&mut self) {
1328                         if std::thread::panicking() {
1329                                 return;
1330                         }
1331
1332                         if !self.expectations.borrow().is_empty() {
1333                                 panic!("Unsatisfied payment expectations: {:?}", self.expectations.borrow());
1334                         }
1335                 }
1336         }
1337
1338         impl Payer for TestPayer {
1339                 fn node_id(&self) -> PublicKey {
1340                         let secp_ctx = Secp256k1::new();
1341                         PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap())
1342                 }
1343
1344                 fn first_hops(&self) -> Vec<ChannelDetails> {
1345                         Vec::new()
1346                 }
1347
1348                 fn send_payment(
1349                         &self, route: &Route, _payment_hash: PaymentHash,
1350                         _payment_secret: &Option<PaymentSecret>
1351                 ) -> Result<PaymentId, PaymentSendFailure> {
1352                         self.check_value_msats(Amount::ForInvoice(route.get_total_amount()));
1353                         self.check_attempts()
1354                 }
1355
1356                 fn send_spontaneous_payment(
1357                         &self, route: &Route, _payment_preimage: PaymentPreimage,
1358                 ) -> Result<PaymentId, PaymentSendFailure> {
1359                         self.check_value_msats(Amount::Spontaneous(route.get_total_amount()));
1360                         self.check_attempts()
1361                 }
1362
1363                 fn retry_payment(
1364                         &self, route: &Route, _payment_id: PaymentId
1365                 ) -> Result<(), PaymentSendFailure> {
1366                         self.check_value_msats(Amount::OnRetry(route.get_total_amount()));
1367                         self.check_attempts().map(|_| ())
1368                 }
1369         }
1370
1371         // *** Full Featured Functional Tests with a Real ChannelManager ***
1372         struct ManualRouter(RefCell<VecDeque<Result<Route, LightningError>>>);
1373
1374         impl<S: Score> Router<S> for ManualRouter {
1375                 fn find_route(
1376                         &self, _payer: &PublicKey, _params: &RouteParameters, _payment_hash: &PaymentHash,
1377                         _first_hops: Option<&[&ChannelDetails]>, _scorer: &S
1378                 ) -> Result<Route, LightningError> {
1379                         self.0.borrow_mut().pop_front().unwrap()
1380                 }
1381         }
1382         impl ManualRouter {
1383                 fn expect_find_route(&self, result: Result<Route, LightningError>) {
1384                         self.0.borrow_mut().push_back(result);
1385                 }
1386         }
1387         impl Drop for ManualRouter {
1388                 fn drop(&mut self) {
1389                         if std::thread::panicking() {
1390                                 return;
1391                         }
1392                         assert!(self.0.borrow_mut().is_empty());
1393                 }
1394         }
1395
1396         #[test]
1397         fn retry_multi_path_single_failed_payment() {
1398                 // Tests that we can/will retry after a single path of an MPP payment failed immediately
1399                 let chanmon_cfgs = create_chanmon_cfgs(2);
1400                 let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
1401                 let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None, None]);
1402                 let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
1403
1404                 create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0, InitFeatures::known(), InitFeatures::known());
1405                 create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0, InitFeatures::known(), InitFeatures::known());
1406                 let chans = nodes[0].node.list_usable_channels();
1407                 let mut route = Route {
1408                         paths: vec![
1409                                 vec![RouteHop {
1410                                         pubkey: nodes[1].node.get_our_node_id(),
1411                                         node_features: NodeFeatures::known(),
1412                                         short_channel_id: chans[0].short_channel_id.unwrap(),
1413                                         channel_features: ChannelFeatures::known(),
1414                                         fee_msat: 10_000,
1415                                         cltv_expiry_delta: 100,
1416                                 }],
1417                                 vec![RouteHop {
1418                                         pubkey: nodes[1].node.get_our_node_id(),
1419                                         node_features: NodeFeatures::known(),
1420                                         short_channel_id: chans[1].short_channel_id.unwrap(),
1421                                         channel_features: ChannelFeatures::known(),
1422                                         fee_msat: 100_000_001, // Our default max-HTLC-value is 10% of the channel value, which this is one more than
1423                                         cltv_expiry_delta: 100,
1424                                 }],
1425                         ],
1426                         payee: Some(Payee::from_node_id(nodes[1].node.get_our_node_id())),
1427                 };
1428                 let router = ManualRouter(RefCell::new(VecDeque::new()));
1429                 router.expect_find_route(Ok(route.clone()));
1430                 // On retry, split the payment across both channels.
1431                 route.paths[0][0].fee_msat = 50_000_001;
1432                 route.paths[1][0].fee_msat = 50_000_000;
1433                 router.expect_find_route(Ok(route.clone()));
1434
1435                 let event_handler = |_: &_| { panic!(); };
1436                 let scorer = RefCell::new(TestScorer::new());
1437                 let invoice_payer = InvoicePayer::new(nodes[0].node, router, &scorer, nodes[0].logger, event_handler, RetryAttempts(1));
1438
1439                 assert!(invoice_payer.pay_invoice(&create_invoice_from_channelmanager(
1440                         &nodes[1].node, nodes[1].keys_manager, Currency::Bitcoin, Some(100_010_000), "Invoice".to_string()).unwrap())
1441                         .is_ok());
1442                 let htlc_msgs = nodes[0].node.get_and_clear_pending_msg_events();
1443                 assert_eq!(htlc_msgs.len(), 2);
1444                 check_added_monitors!(nodes[0], 2);
1445         }
1446
1447         #[test]
1448         fn immediate_retry_on_failure() {
1449                 // Tests that we can/will retry immediately after a failure
1450                 let chanmon_cfgs = create_chanmon_cfgs(2);
1451                 let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
1452                 let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None, None]);
1453                 let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
1454
1455                 create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0, InitFeatures::known(), InitFeatures::known());
1456                 create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0, InitFeatures::known(), InitFeatures::known());
1457                 let chans = nodes[0].node.list_usable_channels();
1458                 let mut route = Route {
1459                         paths: vec![
1460                                 vec![RouteHop {
1461                                         pubkey: nodes[1].node.get_our_node_id(),
1462                                         node_features: NodeFeatures::known(),
1463                                         short_channel_id: chans[0].short_channel_id.unwrap(),
1464                                         channel_features: ChannelFeatures::known(),
1465                                         fee_msat: 100_000_001, // Our default max-HTLC-value is 10% of the channel value, which this is one more than
1466                                         cltv_expiry_delta: 100,
1467                                 }],
1468                         ],
1469                         payee: Some(Payee::from_node_id(nodes[1].node.get_our_node_id())),
1470                 };
1471                 let router = ManualRouter(RefCell::new(VecDeque::new()));
1472                 router.expect_find_route(Ok(route.clone()));
1473                 // On retry, split the payment across both channels.
1474                 route.paths.push(route.paths[0].clone());
1475                 route.paths[0][0].short_channel_id = chans[1].short_channel_id.unwrap();
1476                 route.paths[0][0].fee_msat = 50_000_000;
1477                 route.paths[1][0].fee_msat = 50_000_001;
1478                 router.expect_find_route(Ok(route.clone()));
1479
1480                 let event_handler = |_: &_| { panic!(); };
1481                 let scorer = RefCell::new(TestScorer::new());
1482                 let invoice_payer = InvoicePayer::new(nodes[0].node, router, &scorer, nodes[0].logger, event_handler, RetryAttempts(1));
1483
1484                 assert!(invoice_payer.pay_invoice(&create_invoice_from_channelmanager(
1485                         &nodes[1].node, nodes[1].keys_manager, Currency::Bitcoin, Some(100_010_000), "Invoice".to_string()).unwrap())
1486                         .is_ok());
1487                 let htlc_msgs = nodes[0].node.get_and_clear_pending_msg_events();
1488                 assert_eq!(htlc_msgs.len(), 2);
1489                 check_added_monitors!(nodes[0], 2);
1490         }
1491 }