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