_ 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`] uses its [`Router`] parameterization for optionally notifying scorers upon
  19 //! receiving the [`Event::PaymentPathFailed`] and [`Event::PaymentPathSuccessful`] events.
  20 //! It also does the same for payment probe failure and success events using [`Event::ProbeFailed`]
  21 //! and [`Event::ProbeSuccessful`].
  22 //!
  23 //! [`InvoicePayer`] is capable of retrying failed payments. It accomplishes this by implementing
  24 //! [`EventHandler`] which decorates a user-provided handler. It will intercept any
  25 //! [`Event::PaymentPathFailed`] events and retry the failed paths for a fixed number of total
  26 //! attempts or until retry is no longer possible. In such a situation, [`InvoicePayer`] will pass
  27 //! along the events to the user-provided handler.
  28 //!
  29 //! # Example
  30 //!
  31 //! ```
  32 //! # extern crate lightning;
  33 //! # extern crate lightning_invoice;
  34 //! # extern crate secp256k1;
  35 //! #
  36 //! # use lightning::io;
  37 //! # use lightning::ln::{PaymentHash, PaymentPreimage, PaymentSecret};
  38 //! # use lightning::ln::channelmanager::{ChannelDetails, PaymentId, PaymentSendFailure};
  39 //! # use lightning::ln::msgs::LightningError;
  40 //! # use lightning::routing::gossip::NodeId;
  41 //! # use lightning::routing::router::{Route, RouteHop, RouteParameters};
  42 //! # use lightning::routing::scoring::{ChannelUsage, Score};
  43 //! # use lightning::util::events::{Event, EventHandler, EventsProvider};
  44 //! # use lightning::util::logger::{Logger, Record};
  45 //! # use lightning::util::ser::{Writeable, Writer};
  46 //! # use lightning_invoice::Invoice;
  47 //! # use lightning_invoice::payment::{InFlightHtlcs, InvoicePayer, Payer, Retry, Router};
  48 //! # use secp256k1::PublicKey;
  49 //! # use std::cell::RefCell;
  50 //! # use std::ops::Deref;
  51 //! #
  52 //! # struct FakeEventProvider {}
  53 //! # impl EventsProvider for FakeEventProvider {
  54 //! #     fn process_pending_events<H: Deref>(&self, handler: H) where H::Target: EventHandler {}
  55 //! # }
  56 //! #
  57 //! # struct FakePayer {}
  58 //! # impl Payer for FakePayer {
  59 //! #     fn node_id(&self) -> PublicKey { unimplemented!() }
  60 //! #     fn first_hops(&self) -> Vec<ChannelDetails> { unimplemented!() }
  61 //! #     fn send_payment(
  62 //! #         &self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>
  63 //! #     ) -> Result<PaymentId, PaymentSendFailure> { unimplemented!() }
  64 //! #     fn send_spontaneous_payment(
  65 //! #         &self, route: &Route, payment_preimage: PaymentPreimage
  66 //! #     ) -> Result<PaymentId, PaymentSendFailure> { unimplemented!() }
  67 //! #     fn retry_payment(
  68 //! #         &self, route: &Route, payment_id: PaymentId
  69 //! #     ) -> Result<(), PaymentSendFailure> { unimplemented!() }
  70 //! #     fn abandon_payment(&self, payment_id: PaymentId) { unimplemented!() }
  71 //! # }
  72 //! #
  73 //! # struct FakeRouter {}
  74 //! # impl Router for FakeRouter {
  75 //! #     fn find_route(
  76 //! #         &self, payer: &PublicKey, params: &RouteParameters, payment_hash: &PaymentHash,
  77 //! #         first_hops: Option<&[&ChannelDetails]>, _inflight_htlcs: InFlightHtlcs
  78 //! #     ) -> Result<Route, LightningError> { unimplemented!() }
  79 //! #
  80 //! #     fn notify_payment_path_failed(&self, path: &[&RouteHop], short_channel_id: u64) {  unimplemented!() }
  81 //! #     fn notify_payment_path_successful(&self, path: &[&RouteHop]) {  unimplemented!() }
  82 //! #     fn notify_payment_probe_successful(&self, path: &[&RouteHop]) {  unimplemented!() }
  83 //! #     fn notify_payment_probe_failed(&self, path: &[&RouteHop], short_channel_id: u64) { unimplemented!() }
  84 //! # }
  85 //! #
  86 //! # struct FakeScorer {}
  87 //! # impl Writeable for FakeScorer {
  88 //! #     fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> { unimplemented!(); }
  89 //! # }
  90 //! # impl Score for FakeScorer {
  91 //! #     fn channel_penalty_msat(
  92 //! #         &self, _short_channel_id: u64, _source: &NodeId, _target: &NodeId, _usage: ChannelUsage
  93 //! #     ) -> u64 { 0 }
  94 //! #     fn payment_path_failed(&mut self, _path: &[&RouteHop], _short_channel_id: u64) {}
  95 //! #     fn payment_path_successful(&mut self, _path: &[&RouteHop]) {}
  96 //! #     fn probe_failed(&mut self, _path: &[&RouteHop], _short_channel_id: u64) {}
  97 //! #     fn probe_successful(&mut self, _path: &[&RouteHop]) {}
  98 //! # }
  99 //! #
 100 //! # struct FakeLogger {}
 101 //! # impl Logger for FakeLogger {
 102 //! #     fn log(&self, record: &Record) { unimplemented!() }
 103 //! # }
 104 //! #
 105 //! # fn main() {
 106 //! let event_handler = |event: &Event| {
 107 //!     match event {
 108 //!         Event::PaymentPathFailed { .. } => println!("payment failed after retries"),
 109 //!         Event::PaymentSent { .. } => println!("payment successful"),
 110 //!         _ => {},
 111 //!     }
 112 //! };
 113 //! # let payer = FakePayer {};
 114 //! # let router = FakeRouter {};
 115 //! # let scorer = RefCell::new(FakeScorer {});
 116 //! # let logger = FakeLogger {};
 117 //! let invoice_payer = InvoicePayer::new(&payer, router, &logger, event_handler, Retry::Attempts(2));
 118 //!
 119 //! let invoice = "...";
 120 //! if let Ok(invoice) = invoice.parse::<Invoice>() {
 121 //!     invoice_payer.pay_invoice(&invoice).unwrap();
 122 //!
 123 //! # let event_provider = FakeEventProvider {};
 124 //!     loop {
 125 //!         event_provider.process_pending_events(&invoice_payer);
 126 //!     }
 127 //! }
 128 //! # }
 129 //! ```
 130 //!
 131 //! # Note
 132 //!
 133 //! The [`Route`] is computed before each payment attempt. Any updates affecting path finding such
 134 //! as updates to the network graph or changes to channel scores should be applied prior to
 135 //! retries, typically by way of composing [`EventHandler`]s accordingly.
 136
 137 use crate::Invoice;
 138
 139 use bitcoin_hashes::Hash;
 140 use bitcoin_hashes::sha256::Hash as Sha256;
 141
 142 use crate::prelude::*;
 143 use lightning::io;
 144 use lightning::ln::{PaymentHash, PaymentPreimage, PaymentSecret};
 145 use lightning::ln::channelmanager::{ChannelDetails, PaymentId, PaymentSendFailure};
 146 use lightning::ln::msgs::LightningError;
 147 use lightning::routing::gossip::NodeId;
 148 use lightning::routing::router::{PaymentParameters, Route, RouteHop, RouteParameters};
 149 use lightning::util::errors::APIError;
 150 use lightning::util::events::{Event, EventHandler};
 151 use lightning::util::logger::Logger;
 152 use lightning::util::ser::Writeable;
 153 use time_utils::Time;
 154 use crate::sync::Mutex;
 155
 156 use secp256k1::PublicKey;
 157
 158 use core::fmt;
 159 use core::fmt::{Debug, Display, Formatter};
 160 use core::ops::Deref;
 161 use core::time::Duration;
 162 #[cfg(feature = "std")]
 163 use std::time::SystemTime;
 164
 165 /// A utility for paying [`Invoice`]s and sending spontaneous payments.
 166 ///
 167 /// See [module-level documentation] for details.
 168 ///
 169 /// [module-level documentation]: crate::payment
 170 pub type InvoicePayer<P, R, L, E> = InvoicePayerUsingTime::<P, R, L, E, ConfiguredTime>;
 171
 172 #[cfg(not(feature = "no-std"))]
 173 type ConfiguredTime = std::time::Instant;
 174 #[cfg(feature = "no-std")]
 175 use time_utils;
 176 #[cfg(feature = "no-std")]
 177 type ConfiguredTime = time_utils::Eternity;
 178
 179 /// (C-not exported) generally all users should use the [`InvoicePayer`] type alias.
 180 pub struct InvoicePayerUsingTime<P: Deref, R: Router, L: Deref, E: EventHandler, T: Time>
 181 where
 182         P::Target: Payer,
 183         L::Target: Logger,
 184 {
 185         payer: P,
 186         router: R,
 187         logger: L,
 188         event_handler: E,
 189         /// Caches the overall attempts at making a payment, which is updated prior to retrying.
 190         payment_cache: Mutex<HashMap<PaymentHash, PaymentInfo<T>>>,
 191         retry: Retry,
 192 }
 193
 194 /// Used by [`InvoicePayerUsingTime::payment_cache`] to track the payments that are either
 195 /// currently being made, or have outstanding paths that need retrying.
 196 struct PaymentInfo<T: Time> {
 197         attempts: PaymentAttempts<T>,
 198         paths: Vec<Vec<RouteHop>>,
 199 }
 200
 201 impl<T: Time> PaymentInfo<T> {
 202         fn new() -> Self {
 203                 PaymentInfo {
 204                         attempts: PaymentAttempts::new(),
 205                         paths: vec![],
 206                 }
 207         }
 208 }
 209
 210 /// Storing minimal payment attempts information required for determining if a outbound payment can
 211 /// be retried.
 212 #[derive(Clone, Copy)]
 213 struct PaymentAttempts<T: Time> {
 214         /// This count will be incremented only after the result of the attempt is known. When it's 0,
 215         /// it means the result of the first attempt is now known yet.
 216         count: usize,
 217         /// This field is only used when retry is [`Retry::Timeout`] which is only build with feature std
 218         first_attempted_at: T
 219 }
 220
 221 impl<T: Time> PaymentAttempts<T> {
 222         fn new() -> Self {
 223                 PaymentAttempts {
 224                         count: 0,
 225                         first_attempted_at: T::now()
 226                 }
 227         }
 228 }
 229
 230 impl<T: Time> Display for PaymentAttempts<T> {
 231         fn fmt(&self, f: &mut Formatter) -> Result<(), fmt::Error> {
 232                 #[cfg(feature = "no-std")]
 233                 return write!( f, "attempts: {}", self.count);
 234                 #[cfg(not(feature = "no-std"))]
 235                 return write!(
 236                         f,
 237                         "attempts: {}, duration: {}s",
 238                         self.count,
 239                         T::now().duration_since(self.first_attempted_at).as_secs()
 240                 );
 241         }
 242 }
 243
 244 /// A trait defining behavior of an [`Invoice`] payer.
 245 pub trait Payer {
 246         /// Returns the payer's node id.
 247         fn node_id(&self) -> PublicKey;
 248
 249         /// Returns the payer's channels.
 250         fn first_hops(&self) -> Vec<ChannelDetails>;
 251
 252         /// Sends a payment over the Lightning Network using the given [`Route`].
 253         fn send_payment(
 254                 &self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>
 255         ) -> Result<PaymentId, PaymentSendFailure>;
 256
 257         /// Sends a spontaneous payment over the Lightning Network using the given [`Route`].
 258         fn send_spontaneous_payment(
 259                 &self, route: &Route, payment_preimage: PaymentPreimage
 260         ) -> Result<PaymentId, PaymentSendFailure>;
 261
 262         /// Retries a failed payment path for the [`PaymentId`] using the given [`Route`].
 263         fn retry_payment(&self, route: &Route, payment_id: PaymentId) -> Result<(), PaymentSendFailure>;
 264
 265         /// Signals that no further retries for the given payment will occur.
 266         fn abandon_payment(&self, payment_id: PaymentId);
 267 }
 268
 269 /// A trait defining behavior for routing an [`Invoice`] payment.
 270 pub trait Router {
 271         /// Finds a [`Route`] between `payer` and `payee` for a payment with the given values.
 272         fn find_route(
 273                 &self, payer: &PublicKey, route_params: &RouteParameters, payment_hash: &PaymentHash,
 274                 first_hops: Option<&[&ChannelDetails]>, inflight_htlcs: InFlightHtlcs
 275         ) -> Result<Route, LightningError>;
 276         /// Lets the router know that payment through a specific path has failed.
 277         fn notify_payment_path_failed(&self, path: &[&RouteHop], short_channel_id: u64);
 278         /// Lets the router know that payment through a specific path was successful.
 279         fn notify_payment_path_successful(&self, path: &[&RouteHop]);
 280         /// Lets the router know that a payment probe was successful.
 281         fn notify_payment_probe_successful(&self, path: &[&RouteHop]);
 282         /// Lets the router know that a payment probe failed.
 283         fn notify_payment_probe_failed(&self, path: &[&RouteHop], short_channel_id: u64);
 284 }
 285
 286 /// Strategies available to retry payment path failures for an [`Invoice`].
 287 ///
 288 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
 289 pub enum Retry {
 290         /// Max number of attempts to retry payment.
 291         ///
 292         /// Note that this is the number of *path* failures, not full payment retries. For multi-path
 293         /// payments, if this is less than the total number of paths, we will never even retry all of the
 294         /// payment's paths.
 295         Attempts(usize),
 296         #[cfg(feature = "std")]
 297         /// Time elapsed before abandoning retries for a payment.
 298         Timeout(Duration),
 299 }
 300
 301 impl Retry {
 302         fn is_retryable_now<T: Time>(&self, attempts: &PaymentAttempts<T>) -> bool {
 303                 match (self, attempts) {
 304                         (Retry::Attempts(max_retry_count), PaymentAttempts { count, .. }) => {
 305                                 max_retry_count >= &count
 306                         },
 307                         #[cfg(feature = "std")]
 308                         (Retry::Timeout(max_duration), PaymentAttempts { first_attempted_at, .. } ) =>
 309                                 *max_duration >= T::now().duration_since(*first_attempted_at),
 310                 }
 311         }
 312 }
 313
 314 /// An error that may occur when making a payment.
 315 #[derive(Clone, Debug)]
 316 pub enum PaymentError {
 317         /// An error resulting from the provided [`Invoice`] or payment hash.
 318         Invoice(&'static str),
 319         /// An error occurring when finding a route.
 320         Routing(LightningError),
 321         /// An error occurring when sending a payment.
 322         Sending(PaymentSendFailure),
 323 }
 324
 325 impl<P: Deref, R: Router, L: Deref, E: EventHandler, T: Time> InvoicePayerUsingTime<P, R, L, E, T>
 326 where
 327         P::Target: Payer,
 328         L::Target: Logger,
 329 {
 330         /// Creates an invoice payer that retries failed payment paths.
 331         ///
 332         /// Will forward any [`Event::PaymentPathFailed`] events to the decorated `event_handler` once
 333         /// `retry` has been exceeded for a given [`Invoice`].
 334         pub fn new(
 335                 payer: P, router: R, logger: L, event_handler: E, retry: Retry
 336         ) -> Self {
 337                 Self {
 338                         payer,
 339                         router,
 340                         logger,
 341                         event_handler,
 342                         payment_cache: Mutex::new(HashMap::new()),
 343                         retry,
 344                 }
 345         }
 346
 347         /// Pays the given [`Invoice`], caching it for later use in case a retry is needed.
 348         ///
 349         /// You should ensure that the `invoice.payment_hash()` is unique and the same payment_hash has
 350         /// never been paid before. Because [`InvoicePayer`] is stateless no effort is made to do so
 351         /// for you.
 352         pub fn pay_invoice(&self, invoice: &Invoice) -> Result<PaymentId, PaymentError> {
 353                 if invoice.amount_milli_satoshis().is_none() {
 354                         Err(PaymentError::Invoice("amount missing"))
 355                 } else {
 356                         self.pay_invoice_using_amount(invoice, None)
 357                 }
 358         }
 359
 360         /// Pays the given zero-value [`Invoice`] using the given amount, caching it for later use in
 361         /// case a retry is needed.
 362         ///
 363         /// You should ensure that the `invoice.payment_hash()` is unique and the same payment_hash has
 364         /// never been paid before. Because [`InvoicePayer`] is stateless no effort is made to do so
 365         /// for you.
 366         pub fn pay_zero_value_invoice(
 367                 &self, invoice: &Invoice, amount_msats: u64
 368         ) -> Result<PaymentId, PaymentError> {
 369                 if invoice.amount_milli_satoshis().is_some() {
 370                         Err(PaymentError::Invoice("amount unexpected"))
 371                 } else {
 372                         self.pay_invoice_using_amount(invoice, Some(amount_msats))
 373                 }
 374         }
 375
 376         fn pay_invoice_using_amount(
 377                 &self, invoice: &Invoice, amount_msats: Option<u64>
 378         ) -> Result<PaymentId, PaymentError> {
 379                 debug_assert!(invoice.amount_milli_satoshis().is_some() ^ amount_msats.is_some());
 380
 381                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 382                 match self.payment_cache.lock().unwrap().entry(payment_hash) {
 383                         hash_map::Entry::Occupied(_) => return Err(PaymentError::Invoice("payment pending")),
 384                         hash_map::Entry::Vacant(entry) => entry.insert(PaymentInfo::new()),
 385                 };
 386
 387                 let payment_secret = Some(invoice.payment_secret().clone());
 388                 let mut payment_params = PaymentParameters::from_node_id(invoice.recover_payee_pub_key())
 389                         .with_expiry_time(expiry_time_from_unix_epoch(&invoice).as_secs())
 390                         .with_route_hints(invoice.route_hints());
 391                 if let Some(features) = invoice.features() {
 392                         payment_params = payment_params.with_features(features.clone());
 393                 }
 394                 let route_params = RouteParameters {
 395                         payment_params,
 396                         final_value_msat: invoice.amount_milli_satoshis().or(amount_msats).unwrap(),
 397                         final_cltv_expiry_delta: invoice.min_final_cltv_expiry() as u32,
 398                 };
 399
 400                 let send_payment = |route: &Route| {
 401                         self.payer.send_payment(route, payment_hash, &payment_secret)
 402                 };
 403
 404                 self.pay_internal(&route_params, payment_hash, send_payment)
 405                         .map_err(|e| { self.payment_cache.lock().unwrap().remove(&payment_hash); e })
 406         }
 407
 408         /// Pays `pubkey` an amount using the hash of the given preimage, caching it for later use in
 409         /// case a retry is needed.
 410         ///
 411         /// You should ensure that `payment_preimage` is unique and that its `payment_hash` has never
 412         /// been paid before. Because [`InvoicePayer`] is stateless no effort is made to do so for you.
 413         pub fn pay_pubkey(
 414                 &self, pubkey: PublicKey, payment_preimage: PaymentPreimage, amount_msats: u64,
 415                 final_cltv_expiry_delta: u32
 416         ) -> Result<PaymentId, PaymentError> {
 417                 let payment_hash = PaymentHash(Sha256::hash(&payment_preimage.0).into_inner());
 418                 match self.payment_cache.lock().unwrap().entry(payment_hash) {
 419                         hash_map::Entry::Occupied(_) => return Err(PaymentError::Invoice("payment pending")),
 420                         hash_map::Entry::Vacant(entry) => entry.insert(PaymentInfo::new()),
 421                 };
 422
 423                 let route_params = RouteParameters {
 424                         payment_params: PaymentParameters::for_keysend(pubkey),
 425                         final_value_msat: amount_msats,
 426                         final_cltv_expiry_delta,
 427                 };
 428
 429                 let send_payment = |route: &Route| {
 430                         self.payer.send_spontaneous_payment(route, payment_preimage)
 431                 };
 432                 self.pay_internal(&route_params, payment_hash, send_payment)
 433                         .map_err(|e| { self.payment_cache.lock().unwrap().remove(&payment_hash); e })
 434         }
 435
 436         fn pay_internal<F: FnOnce(&Route) -> Result<PaymentId, PaymentSendFailure> + Copy>(
 437                 &self, params: &RouteParameters, payment_hash: PaymentHash, send_payment: F,
 438         ) -> Result<PaymentId, PaymentError> {
 439                 #[cfg(feature = "std")] {
 440                         if has_expired(params) {
 441                                 log_trace!(self.logger, "Invoice expired prior to send for payment {}", log_bytes!(payment_hash.0));
 442                                 return Err(PaymentError::Invoice("Invoice expired prior to send"));
 443                         }
 444                 }
 445
 446                 let payer = self.payer.node_id();
 447                 let first_hops = self.payer.first_hops();
 448                 let inflight_htlcs = self.create_inflight_map();
 449                 let route = self.router.find_route(
 450                         &payer, &params, &payment_hash, Some(&first_hops.iter().collect::<Vec<_>>()),
 451                         inflight_htlcs
 452                 ).map_err(|e| PaymentError::Routing(e))?;
 453
 454                 match send_payment(&route) {
 455                         Ok(payment_id) => {
 456                                 for path in route.paths {
 457                                         self.process_path_inflight_htlcs(payment_hash, path);
 458                                 }
 459                                 Ok(payment_id)
 460                         },
 461                         Err(e) => match e {
 462                                 PaymentSendFailure::ParameterError(_) => Err(e),
 463                                 PaymentSendFailure::PathParameterError(_) => Err(e),
 464                                 PaymentSendFailure::AllFailedRetrySafe(_) => {
 465                                         let mut payment_cache = self.payment_cache.lock().unwrap();
 466                                         let payment_info = payment_cache.get_mut(&payment_hash).unwrap();
 467                                         payment_info.attempts.count += 1;
 468                                         if self.retry.is_retryable_now(&payment_info.attempts) {
 469                                                 core::mem::drop(payment_cache);
 470                                                 Ok(self.pay_internal(params, payment_hash, send_payment)?)
 471                                         } else {
 472                                                 Err(e)
 473                                         }
 474                                 },
 475                                 PaymentSendFailure::PartialFailure { failed_paths_retry, payment_id, results } => {
 476                                         // If a `PartialFailure` event returns a result that is an `Ok()`, it means that
 477                                         // part of our payment is retried. When we receive `MonitorUpdateFailed`, it
 478                                         // means that we are still waiting for our channel monitor update to be completed.
 479                                         for (result, path) in results.iter().zip(route.paths.into_iter()) {
 480                                                 match result {
 481                                                         Ok(_) | Err(APIError::MonitorUpdateFailed) => {
 482                                                                 self.process_path_inflight_htlcs(payment_hash, path);
 483                                                         },
 484                                                         _ => {},
 485                                                 }
 486                                         }
 487
 488                                         if let Some(retry_data) = failed_paths_retry {
 489                                                 // Some paths were sent, even if we failed to send the full MPP value our
 490                                                 // recipient may misbehave and claim the funds, at which point we have to
 491                                                 // consider the payment sent, so return `Ok()` here, ignoring any retry
 492                                                 // errors.
 493                                                 let _ = self.retry_payment(payment_id, payment_hash, &retry_data);
 494                                                 Ok(payment_id)
 495                                         } else {
 496                                                 // This may happen if we send a payment and some paths fail, but
 497                                                 // only due to a temporary monitor failure or the like, implying
 498                                                 // they're really in-flight, but we haven't sent the initial
 499                                                 // HTLC-Add messages yet.
 500                                                 Ok(payment_id)
 501                                         }
 502                                 },
 503                         },
 504                 }.map_err(|e| PaymentError::Sending(e))
 505         }
 506
 507         // Takes in a path to have its information stored in `payment_cache`. This is done for paths
 508         // that are pending retry.
 509         fn process_path_inflight_htlcs(&self, payment_hash: PaymentHash, path: Vec<RouteHop>) {
 510                 self.payment_cache.lock().unwrap().entry(payment_hash)
 511                         .or_insert_with(|| PaymentInfo::new())
 512                         .paths.push(path);
 513         }
 514
 515         // Find the path we want to remove in `payment_cache`. If it doesn't exist, do nothing.
 516         fn remove_path_inflight_htlcs(&self, payment_hash: PaymentHash, path: &Vec<RouteHop>) {
 517                 self.payment_cache.lock().unwrap().entry(payment_hash)
 518                         .and_modify(|payment_info| {
 519                                 if let Some(idx) = payment_info.paths.iter().position(|p| p == path) {
 520                                         payment_info.paths.swap_remove(idx);
 521                                 }
 522                         });
 523         }
 524
 525         fn retry_payment(
 526                 &self, payment_id: PaymentId, payment_hash: PaymentHash, params: &RouteParameters
 527         ) -> Result<(), ()> {
 528                 let attempts = self.payment_cache.lock().unwrap().entry(payment_hash)
 529                         .and_modify(|info| info.attempts.count += 1 )
 530                         .or_insert_with(|| PaymentInfo {
 531                                 attempts: PaymentAttempts {
 532                                         count: 1,
 533                                         first_attempted_at: T::now(),
 534                                 },
 535                                 paths: vec![],
 536                         }).attempts;
 537
 538                 if !self.retry.is_retryable_now(&attempts) {
 539                         log_trace!(self.logger, "Payment {} exceeded maximum attempts; not retrying ({})", log_bytes!(payment_hash.0), attempts);
 540                         return Err(());
 541                 }
 542
 543                 #[cfg(feature = "std")] {
 544                         if has_expired(params) {
 545                                 log_trace!(self.logger, "Invoice expired for payment {}; not retrying ({:})", log_bytes!(payment_hash.0), attempts);
 546                                 return Err(());
 547                         }
 548                 }
 549
 550                 let payer = self.payer.node_id();
 551                 let first_hops = self.payer.first_hops();
 552                 let inflight_htlcs = self.create_inflight_map();
 553
 554                 let route = self.router.find_route(
 555                         &payer, &params, &payment_hash, Some(&first_hops.iter().collect::<Vec<_>>()),
 556                         inflight_htlcs
 557                 );
 558
 559                 if route.is_err() {
 560                         log_trace!(self.logger, "Failed to find a route for payment {}; not retrying ({:})", log_bytes!(payment_hash.0), attempts);
 561                         return Err(());
 562                 }
 563
 564                 match self.payer.retry_payment(&route.as_ref().unwrap(), payment_id) {
 565                         Ok(()) => {
 566                                 for path in route.unwrap().paths.into_iter() {
 567                                         self.process_path_inflight_htlcs(payment_hash, path);
 568                                 }
 569                                 Ok(())
 570                         },
 571                         Err(PaymentSendFailure::ParameterError(_)) |
 572                         Err(PaymentSendFailure::PathParameterError(_)) => {
 573                                 log_trace!(self.logger, "Failed to retry for payment {} due to bogus route/payment data, not retrying.", log_bytes!(payment_hash.0));
 574                                 Err(())
 575                         },
 576                         Err(PaymentSendFailure::AllFailedRetrySafe(_)) => {
 577                                 self.retry_payment(payment_id, payment_hash, params)
 578                         },
 579                         Err(PaymentSendFailure::PartialFailure { failed_paths_retry, results, .. }) => {
 580                                 // If a `PartialFailure` error contains a result that is an `Ok()`, it means that
 581                                 // part of our payment is retried. When we receive `MonitorUpdateFailed`, it
 582                                 // means that we are still waiting for our channel monitor update to complete.
 583                                 for (result, path) in results.iter().zip(route.unwrap().paths.into_iter()) {
 584                                         match result {
 585                                                 Ok(_) | Err(APIError::MonitorUpdateFailed) => {
 586                                                         self.process_path_inflight_htlcs(payment_hash, path);
 587                                                 },
 588                                                 _ => {},
 589                                         }
 590                                 }
 591
 592                                 if let Some(retry) = failed_paths_retry {
 593                                         // Always return Ok for the same reason as noted in pay_internal.
 594                                         let _ = self.retry_payment(payment_id, payment_hash, &retry);
 595                                 }
 596                                 Ok(())
 597                         },
 598                 }
 599         }
 600
 601         /// Removes the payment cached by the given payment hash.
 602         ///
 603         /// Should be called once a payment has failed or succeeded if not using [`InvoicePayer`] as an
 604         /// [`EventHandler`]. Otherwise, calling this method is unnecessary.
 605         pub fn remove_cached_payment(&self, payment_hash: &PaymentHash) {
 606                 self.payment_cache.lock().unwrap().remove(payment_hash);
 607         }
 608
 609         /// Given a [`PaymentHash`], this function looks up inflight path attempts in the payment_cache.
 610         /// Then, it uses the path information inside the cache to construct a HashMap mapping a channel's
 611         /// short channel id and direction to the amount being sent through it.
 612         ///
 613         /// This function should be called whenever we need information about currently used up liquidity
 614         /// across payments.
 615         fn create_inflight_map(&self) -> InFlightHtlcs {
 616                 let mut total_inflight_map: HashMap<(u64, bool), u64> = HashMap::new();
 617                 // Make an attempt at finding existing payment information from `payment_cache`. If it
 618                 // does not exist, it probably is a fresh payment and we can just return an empty
 619                 // HashMap.
 620                 for payment_info in self.payment_cache.lock().unwrap().values() {
 621                         for path in &payment_info.paths {
 622                                 if path.is_empty() { break };
 623                                 // total_inflight_map needs to be direction-sensitive when keeping track of the HTLC value
 624                                 // that is held up. However, the `hops` array, which is a path returned by `find_route` in
 625                                 // the router excludes the payer node. In the following lines, the payer's information is
 626                                 // hardcoded with an inflight value of 0 so that we can correctly represent the first hop
 627                                 // in our sliding window of two.
 628                                 let our_node_id: PublicKey = self.payer.node_id();
 629                                 let reversed_hops_with_payer = path.iter().rev().skip(1)
 630                                         .map(|hop| hop.pubkey)
 631                                         .chain(core::iter::once(our_node_id));
 632                                 let mut cumulative_msat = 0;
 633
 634                                 // Taking the reversed vector from above, we zip it with just the reversed hops list to
 635                                 // work "backwards" of the given path, since the last hop's `fee_msat` actually represents
 636                                 // the total amount sent.
 637                                 for (next_hop, prev_hop) in path.iter().rev().zip(reversed_hops_with_payer) {
 638                                         cumulative_msat += next_hop.fee_msat;
 639                                         total_inflight_map
 640                                                 .entry((next_hop.short_channel_id, NodeId::from_pubkey(&prev_hop) < NodeId::from_pubkey(&next_hop.pubkey)))
 641                                                 .and_modify(|used_liquidity_msat| *used_liquidity_msat += cumulative_msat)
 642                                                 .or_insert(cumulative_msat);
 643                                 }
 644                         }
 645                 }
 646
 647                 InFlightHtlcs(total_inflight_map)
 648         }
 649 }
 650
 651 fn expiry_time_from_unix_epoch(invoice: &Invoice) -> Duration {
 652         invoice.signed_invoice.raw_invoice.data.timestamp.0 + invoice.expiry_time()
 653 }
 654
 655 #[cfg(feature = "std")]
 656 fn has_expired(route_params: &RouteParameters) -> bool {
 657         if let Some(expiry_time) = route_params.payment_params.expiry_time {
 658                 Invoice::is_expired_from_epoch(&SystemTime::UNIX_EPOCH, Duration::from_secs(expiry_time))
 659         } else { false }
 660 }
 661
 662 impl<P: Deref, R: Router, L: Deref, E: EventHandler, T: Time> EventHandler for InvoicePayerUsingTime<P, R, L, E, T>
 663 where
 664         P::Target: Payer,
 665         L::Target: Logger,
 666 {
 667         fn handle_event(&self, event: &Event) {
 668                 match event {
 669                         Event::PaymentPathFailed { payment_hash, path, ..  }
 670                         | Event::PaymentPathSuccessful { path, payment_hash: Some(payment_hash), .. }
 671                         | Event::ProbeSuccessful { payment_hash, path, .. }
 672                         | Event::ProbeFailed { payment_hash, path, .. } => {
 673                                 self.remove_path_inflight_htlcs(*payment_hash, path);
 674                         },
 675                         _ => {},
 676                 }
 677
 678                 match event {
 679                         Event::PaymentPathFailed {
 680                                 payment_id, payment_hash, payment_failed_permanently, path, short_channel_id, retry, ..
 681                         } => {
 682                                 if let Some(short_channel_id) = short_channel_id {
 683                                         let path = path.iter().collect::<Vec<_>>();
 684                                         self.router.notify_payment_path_failed(&path, *short_channel_id)
 685                                 }
 686
 687                                 if payment_id.is_none() {
 688                                         log_trace!(self.logger, "Payment {} has no id; not retrying", log_bytes!(payment_hash.0));
 689                                 } else if *payment_failed_permanently {
 690                                         log_trace!(self.logger, "Payment {} rejected by destination; not retrying", log_bytes!(payment_hash.0));
 691                                         self.payer.abandon_payment(payment_id.unwrap());
 692                                 } else if retry.is_none() {
 693                                         log_trace!(self.logger, "Payment {} missing retry params; not retrying", log_bytes!(payment_hash.0));
 694                                         self.payer.abandon_payment(payment_id.unwrap());
 695                                 } else if self.retry_payment(payment_id.unwrap(), *payment_hash, retry.as_ref().unwrap()).is_ok() {
 696                                         // We retried at least somewhat, don't provide the PaymentPathFailed event to the user.
 697                                         return;
 698                                 } else {
 699                                         self.payer.abandon_payment(payment_id.unwrap());
 700                                 }
 701                         },
 702                         Event::PaymentFailed { payment_hash, .. } => {
 703                                 self.remove_cached_payment(&payment_hash);
 704                         },
 705                         Event::PaymentPathSuccessful { path, .. } => {
 706                                 let path = path.iter().collect::<Vec<_>>();
 707                                 self.router.notify_payment_path_successful(&path);
 708                         },
 709                         Event::PaymentSent { payment_hash, .. } => {
 710                                 let mut payment_cache = self.payment_cache.lock().unwrap();
 711                                 let attempts = payment_cache
 712                                         .remove(payment_hash)
 713                                         .map_or(1, |payment_info| payment_info.attempts.count + 1);
 714                                 log_trace!(self.logger, "Payment {} succeeded (attempts: {})", log_bytes!(payment_hash.0), attempts);
 715                         },
 716                         Event::ProbeSuccessful { payment_hash, path, .. } => {
 717                                 log_trace!(self.logger, "Probe payment {} of {}msat was successful", log_bytes!(payment_hash.0), path.last().unwrap().fee_msat);
 718                                 let path = path.iter().collect::<Vec<_>>();
 719                                 self.router.notify_payment_probe_successful(&path);
 720                         },
 721                         Event::ProbeFailed { payment_hash, path, short_channel_id, .. } => {
 722                                 if let Some(short_channel_id) = short_channel_id {
 723                                         log_trace!(self.logger, "Probe payment {} of {}msat failed at channel {}", log_bytes!(payment_hash.0), path.last().unwrap().fee_msat, *short_channel_id);
 724                                         let path = path.iter().collect::<Vec<_>>();
 725                                         self.router.notify_payment_probe_failed(&path, *short_channel_id);
 726                                 }
 727                         },
 728                         _ => {},
 729                 }
 730
 731                 // Delegate to the decorated event handler unless the payment is retried.
 732                 self.event_handler.handle_event(event)
 733         }
 734 }
 735
 736 /// A map with liquidity value (in msat) keyed by a short channel id and the direction the HTLC
 737 /// is traveling in. The direction boolean is determined by checking if the HTLC source's public
 738 /// key is less than its destination. See [`InFlightHtlcs::used_liquidity_msat`] for more
 739 /// details.
 740 pub struct InFlightHtlcs(HashMap<(u64, bool), u64>);
 741
 742 impl InFlightHtlcs {
 743         /// Returns liquidity in msat given the public key of the HTLC source, target, and short channel
 744         /// id.
 745         pub fn used_liquidity_msat(&self, source: &NodeId, target: &NodeId, channel_scid: u64) -> Option<u64> {
 746                 self.0.get(&(channel_scid, source < target)).map(|v| *v)
 747         }
 748 }
 749
 750 impl Writeable for InFlightHtlcs {
 751         fn write<W: lightning::util::ser::Writer>(&self, writer: &mut W) -> Result<(), io::Error> { self.0.write(writer) }
 752 }
 753
 754 impl lightning::util::ser::Readable for InFlightHtlcs {
 755         fn read<R: io::Read>(reader: &mut R) -> Result<Self, lightning::ln::msgs::DecodeError> {
 756                 let infight_map: HashMap<(u64, bool), u64> = lightning::util::ser::Readable::read(reader)?;
 757                 Ok(Self(infight_map))
 758         }
 759 }
 760
 761 #[cfg(test)]
 762 mod tests {
 763         use super::*;
 764         use crate::{InvoiceBuilder, Currency};
 765         use utils::{ScorerAccountingForInFlightHtlcs, create_invoice_from_channelmanager_and_duration_since_epoch};
 766         use bitcoin_hashes::sha256::Hash as Sha256;
 767         use lightning::ln::PaymentPreimage;
 768         use lightning::ln::channelmanager;
 769         use lightning::ln::features::{ChannelFeatures, NodeFeatures};
 770         use lightning::ln::functional_test_utils::*;
 771         use lightning::ln::msgs::{ChannelMessageHandler, ErrorAction, LightningError};
 772         use lightning::routing::gossip::{EffectiveCapacity, NodeId};
 773         use lightning::routing::router::{PaymentParameters, Route, RouteHop};
 774         use lightning::routing::scoring::{ChannelUsage, LockableScore, Score};
 775         use lightning::util::test_utils::TestLogger;
 776         use lightning::util::errors::APIError;
 777         use lightning::util::events::{Event, EventsProvider, MessageSendEvent, MessageSendEventsProvider};
 778         use secp256k1::{SecretKey, PublicKey, Secp256k1};
 779         use std::cell::RefCell;
 780         use std::collections::VecDeque;
 781         use std::ops::DerefMut;
 782         use std::time::{SystemTime, Duration};
 783         use time_utils::tests::SinceEpoch;
 784         use DEFAULT_EXPIRY_TIME;
 785         use lightning::util::errors::APIError::{ChannelUnavailable, MonitorUpdateFailed};
 786
 787         fn invoice(payment_preimage: PaymentPreimage) -> Invoice {
 788                 let payment_hash = Sha256::hash(&payment_preimage.0);
 789                 let private_key = SecretKey::from_slice(&[42; 32]).unwrap();
 790
 791                 InvoiceBuilder::new(Currency::Bitcoin)
 792                         .description("test".into())
 793                         .payment_hash(payment_hash)
 794                         .payment_secret(PaymentSecret([0; 32]))
 795                         .duration_since_epoch(duration_since_epoch())
 796                         .min_final_cltv_expiry(144)
 797                         .amount_milli_satoshis(128)
 798                         .build_signed(|hash| {
 799                                 Secp256k1::new().sign_ecdsa_recoverable(hash, &private_key)
 800                         })
 801                         .unwrap()
 802         }
 803
 804         fn duration_since_epoch() -> Duration {
 805                 #[cfg(feature = "std")]
 806                         let duration_since_epoch =
 807                         SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap();
 808                 #[cfg(not(feature = "std"))]
 809                         let duration_since_epoch = Duration::from_secs(1234567);
 810                 duration_since_epoch
 811         }
 812
 813         fn zero_value_invoice(payment_preimage: PaymentPreimage) -> Invoice {
 814                 let payment_hash = Sha256::hash(&payment_preimage.0);
 815                 let private_key = SecretKey::from_slice(&[42; 32]).unwrap();
 816
 817                 InvoiceBuilder::new(Currency::Bitcoin)
 818                         .description("test".into())
 819                         .payment_hash(payment_hash)
 820                         .payment_secret(PaymentSecret([0; 32]))
 821                         .duration_since_epoch(duration_since_epoch())
 822                         .min_final_cltv_expiry(144)
 823                         .build_signed(|hash| {
 824                                 Secp256k1::new().sign_ecdsa_recoverable(hash, &private_key)
 825                         })
 826                         .unwrap()
 827         }
 828
 829         #[cfg(feature = "std")]
 830         fn expired_invoice(payment_preimage: PaymentPreimage) -> Invoice {
 831                 let payment_hash = Sha256::hash(&payment_preimage.0);
 832                 let private_key = SecretKey::from_slice(&[42; 32]).unwrap();
 833                 let duration = duration_since_epoch()
 834                         .checked_sub(Duration::from_secs(DEFAULT_EXPIRY_TIME * 2))
 835                         .unwrap();
 836                 InvoiceBuilder::new(Currency::Bitcoin)
 837                         .description("test".into())
 838                         .payment_hash(payment_hash)
 839                         .payment_secret(PaymentSecret([0; 32]))
 840                         .duration_since_epoch(duration)
 841                         .min_final_cltv_expiry(144)
 842                         .amount_milli_satoshis(128)
 843                         .build_signed(|hash| {
 844                                 Secp256k1::new().sign_ecdsa_recoverable(hash, &private_key)
 845                         })
 846                         .unwrap()
 847         }
 848
 849         fn pubkey() -> PublicKey {
 850                 PublicKey::from_slice(&hex::decode("02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619").unwrap()[..]).unwrap()
 851         }
 852
 853         #[test]
 854         fn pays_invoice_on_first_attempt() {
 855                 let event_handled = core::cell::RefCell::new(false);
 856                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 857
 858                 let payment_preimage = PaymentPreimage([1; 32]);
 859                 let invoice = invoice(payment_preimage);
 860                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 861                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 862
 863                 let payer = TestPayer::new().expect_send(Amount::ForInvoice(final_value_msat));
 864                 let router = TestRouter::new(TestScorer::new());
 865                 let logger = TestLogger::new();
 866                 let invoice_payer =
 867                         InvoicePayer::new(&payer, router, &logger, event_handler, Retry::Attempts(0));
 868
 869                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 870                 assert_eq!(*payer.attempts.borrow(), 1);
 871
 872                 invoice_payer.handle_event(&Event::PaymentSent {
 873                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
 874                 });
 875                 assert_eq!(*event_handled.borrow(), true);
 876                 assert_eq!(*payer.attempts.borrow(), 1);
 877         }
 878
 879         #[test]
 880         fn pays_invoice_on_retry() {
 881                 let event_handled = core::cell::RefCell::new(false);
 882                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 883
 884                 let payment_preimage = PaymentPreimage([1; 32]);
 885                 let invoice = invoice(payment_preimage);
 886                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 887                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 888
 889                 let payer = TestPayer::new()
 890                         .expect_send(Amount::ForInvoice(final_value_msat))
 891                         .expect_send(Amount::OnRetry(final_value_msat / 2));
 892                 let router = TestRouter::new(TestScorer::new());
 893                 let logger = TestLogger::new();
 894                 let invoice_payer =
 895                         InvoicePayer::new(&payer, router, &logger, event_handler, Retry::Attempts(2));
 896
 897                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 898                 assert_eq!(*payer.attempts.borrow(), 1);
 899
 900                 let event = Event::PaymentPathFailed {
 901                         payment_id,
 902                         payment_hash,
 903                         network_update: None,
 904                         payment_failed_permanently: false,
 905                         all_paths_failed: false,
 906                         path: TestRouter::path_for_value(final_value_msat),
 907                         short_channel_id: None,
 908                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 909                 };
 910                 invoice_payer.handle_event(&event);
 911                 assert_eq!(*event_handled.borrow(), false);
 912                 assert_eq!(*payer.attempts.borrow(), 2);
 913
 914                 invoice_payer.handle_event(&Event::PaymentSent {
 915                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
 916                 });
 917                 assert_eq!(*event_handled.borrow(), true);
 918                 assert_eq!(*payer.attempts.borrow(), 2);
 919         }
 920
 921         #[test]
 922         fn pays_invoice_on_partial_failure() {
 923                 let event_handler = |_: &_| { panic!() };
 924
 925                 let payment_preimage = PaymentPreimage([1; 32]);
 926                 let invoice = invoice(payment_preimage);
 927                 let retry = TestRouter::retry_for_invoice(&invoice);
 928                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 929
 930                 let payer = TestPayer::new()
 931                         .fails_with_partial_failure(retry.clone(), OnAttempt(1), None)
 932                         .fails_with_partial_failure(retry, OnAttempt(2), None)
 933                         .expect_send(Amount::ForInvoice(final_value_msat))
 934                         .expect_send(Amount::OnRetry(final_value_msat / 2))
 935                         .expect_send(Amount::OnRetry(final_value_msat / 2));
 936                 let router = TestRouter::new(TestScorer::new());
 937                 let logger = TestLogger::new();
 938                 let invoice_payer =
 939                         InvoicePayer::new(&payer, router, &logger, event_handler, Retry::Attempts(2));
 940
 941                 assert!(invoice_payer.pay_invoice(&invoice).is_ok());
 942         }
 943
 944         #[test]
 945         fn retries_payment_path_for_unknown_payment() {
 946                 let event_handled = core::cell::RefCell::new(false);
 947                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 948
 949                 let payment_preimage = PaymentPreimage([1; 32]);
 950                 let invoice = invoice(payment_preimage);
 951                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 952                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 953
 954                 let payer = TestPayer::new()
 955                         .expect_send(Amount::OnRetry(final_value_msat / 2))
 956                         .expect_send(Amount::OnRetry(final_value_msat / 2));
 957                 let router = TestRouter::new(TestScorer::new());
 958                 let logger = TestLogger::new();
 959                 let invoice_payer =
 960                         InvoicePayer::new(&payer, router, &logger, event_handler, Retry::Attempts(2));
 961
 962                 let payment_id = Some(PaymentId([1; 32]));
 963                 let event = Event::PaymentPathFailed {
 964                         payment_id,
 965                         payment_hash,
 966                         network_update: None,
 967                         payment_failed_permanently: false,
 968                         all_paths_failed: false,
 969                         path: TestRouter::path_for_value(final_value_msat),
 970                         short_channel_id: None,
 971                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 972                 };
 973                 invoice_payer.handle_event(&event);
 974                 assert_eq!(*event_handled.borrow(), false);
 975                 assert_eq!(*payer.attempts.borrow(), 1);
 976
 977                 invoice_payer.handle_event(&event);
 978                 assert_eq!(*event_handled.borrow(), false);
 979                 assert_eq!(*payer.attempts.borrow(), 2);
 980
 981                 invoice_payer.handle_event(&Event::PaymentSent {
 982                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
 983                 });
 984                 assert_eq!(*event_handled.borrow(), true);
 985                 assert_eq!(*payer.attempts.borrow(), 2);
 986         }
 987
 988         #[test]
 989         fn fails_paying_invoice_after_max_retry_counts() {
 990                 let event_handled = core::cell::RefCell::new(false);
 991                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 992
 993                 let payment_preimage = PaymentPreimage([1; 32]);
 994                 let invoice = invoice(payment_preimage);
 995                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 996
 997                 let payer = TestPayer::new()
 998                         .expect_send(Amount::ForInvoice(final_value_msat))
 999                         .expect_send(Amount::OnRetry(final_value_msat / 2))
1000                         .expect_send(Amount::OnRetry(final_value_msat / 2));
1001                 let router = TestRouter::new(TestScorer::new());
1002                 let logger = TestLogger::new();
1003                 let invoice_payer =
1004                         InvoicePayer::new(&payer, router, &logger, event_handler, Retry::Attempts(2));
1005
1006                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
1007                 assert_eq!(*payer.attempts.borrow(), 1);
1008
1009                 let event = Event::PaymentPathFailed {
1010                         payment_id,
1011                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
1012                         network_update: None,
1013                         payment_failed_permanently: false,
1014                         all_paths_failed: true,
1015                         path: TestRouter::path_for_value(final_value_msat),
1016                         short_channel_id: None,
1017                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
1018                 };
1019                 invoice_payer.handle_event(&event);
1020                 assert_eq!(*event_handled.borrow(), false);
1021                 assert_eq!(*payer.attempts.borrow(), 2);
1022
1023                 let event = Event::PaymentPathFailed {
1024                         payment_id,
1025                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
1026                         network_update: None,
1027                         payment_failed_permanently: false,
1028                         all_paths_failed: false,
1029                         path: TestRouter::path_for_value(final_value_msat / 2),
1030                         short_channel_id: None,
1031                         retry: Some(RouteParameters {
1032                                 final_value_msat: final_value_msat / 2, ..TestRouter::retry_for_invoice(&invoice)
1033                         }),
1034                 };
1035                 invoice_payer.handle_event(&event);
1036                 assert_eq!(*event_handled.borrow(), false);
1037                 assert_eq!(*payer.attempts.borrow(), 3);
1038
1039                 invoice_payer.handle_event(&event);
1040                 assert_eq!(*event_handled.borrow(), true);
1041                 assert_eq!(*payer.attempts.borrow(), 3);
1042         }
1043
1044         #[cfg(feature = "std")]
1045         #[test]
1046         fn fails_paying_invoice_after_max_retry_timeout() {
1047                 let event_handled = core::cell::RefCell::new(false);
1048                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1049
1050                 let payment_preimage = PaymentPreimage([1; 32]);
1051                 let invoice = invoice(payment_preimage);
1052                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
1053
1054                 let payer = TestPayer::new()
1055                         .expect_send(Amount::ForInvoice(final_value_msat))
1056                         .expect_send(Amount::OnRetry(final_value_msat / 2));
1057
1058                 let router = TestRouter::new(TestScorer::new());
1059                 let logger = TestLogger::new();
1060                 type InvoicePayerUsingSinceEpoch <P, R, L, E> = InvoicePayerUsingTime::<P, R, L, E, SinceEpoch>;
1061
1062                 let invoice_payer =
1063                         InvoicePayerUsingSinceEpoch::new(&payer, router, &logger, event_handler, Retry::Timeout(Duration::from_secs(120)));
1064
1065                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
1066                 assert_eq!(*payer.attempts.borrow(), 1);
1067
1068                 let event = Event::PaymentPathFailed {
1069                         payment_id,
1070                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
1071                         network_update: None,
1072                         payment_failed_permanently: false,
1073                         all_paths_failed: true,
1074                         path: TestRouter::path_for_value(final_value_msat),
1075                         short_channel_id: None,
1076                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
1077                 };
1078                 invoice_payer.handle_event(&event);
1079                 assert_eq!(*event_handled.borrow(), false);
1080                 assert_eq!(*payer.attempts.borrow(), 2);
1081
1082                 SinceEpoch::advance(Duration::from_secs(121));
1083
1084                 invoice_payer.handle_event(&event);
1085                 assert_eq!(*event_handled.borrow(), true);
1086                 assert_eq!(*payer.attempts.borrow(), 2);
1087         }
1088
1089         #[test]
1090         fn fails_paying_invoice_with_missing_retry_params() {
1091                 let event_handled = core::cell::RefCell::new(false);
1092                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1093
1094                 let payment_preimage = PaymentPreimage([1; 32]);
1095                 let invoice = invoice(payment_preimage);
1096                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
1097
1098                 let payer = TestPayer::new().expect_send(Amount::ForInvoice(final_value_msat));
1099                 let router = TestRouter::new(TestScorer::new());
1100                 let logger = TestLogger::new();
1101                 let invoice_payer =
1102                         InvoicePayer::new(&payer, router, &logger, event_handler, Retry::Attempts(2));
1103
1104                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
1105                 assert_eq!(*payer.attempts.borrow(), 1);
1106
1107                 let event = Event::PaymentPathFailed {
1108                         payment_id,
1109                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
1110                         network_update: None,
1111                         payment_failed_permanently: false,
1112                         all_paths_failed: false,
1113                         path: vec![],
1114                         short_channel_id: None,
1115                         retry: None,
1116                 };
1117                 invoice_payer.handle_event(&event);
1118                 assert_eq!(*event_handled.borrow(), true);
1119                 assert_eq!(*payer.attempts.borrow(), 1);
1120         }
1121
1122         // Expiration is checked only in an std environment
1123         #[cfg(feature = "std")]
1124         #[test]
1125         fn fails_paying_invoice_after_expiration() {
1126                 let event_handled = core::cell::RefCell::new(false);
1127                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1128
1129                 let payer = TestPayer::new();
1130                 let router = TestRouter::new(TestScorer::new());
1131                 let logger = TestLogger::new();
1132                 let invoice_payer =
1133                         InvoicePayer::new(&payer, router, &logger, event_handler, Retry::Attempts(2));
1134
1135                 let payment_preimage = PaymentPreimage([1; 32]);
1136                 let invoice = expired_invoice(payment_preimage);
1137                 if let PaymentError::Invoice(msg) = invoice_payer.pay_invoice(&invoice).unwrap_err() {
1138                         assert_eq!(msg, "Invoice expired prior to send");
1139                 } else { panic!("Expected Invoice Error"); }
1140         }
1141
1142         // Expiration is checked only in an std environment
1143         #[cfg(feature = "std")]
1144         #[test]
1145         fn fails_retrying_invoice_after_expiration() {
1146                 let event_handled = core::cell::RefCell::new(false);
1147                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1148
1149                 let payment_preimage = PaymentPreimage([1; 32]);
1150                 let invoice = invoice(payment_preimage);
1151                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
1152
1153                 let payer = TestPayer::new().expect_send(Amount::ForInvoice(final_value_msat));
1154                 let router = TestRouter::new(TestScorer::new());
1155                 let logger = TestLogger::new();
1156                 let invoice_payer =
1157                         InvoicePayer::new(&payer, router,  &logger, event_handler, Retry::Attempts(2));
1158
1159                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
1160                 assert_eq!(*payer.attempts.borrow(), 1);
1161
1162                 let mut retry_data = TestRouter::retry_for_invoice(&invoice);
1163                 retry_data.payment_params.expiry_time = Some(SystemTime::now()
1164                         .checked_sub(Duration::from_secs(2)).unwrap()
1165                         .duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs());
1166                 let event = Event::PaymentPathFailed {
1167                         payment_id,
1168                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
1169                         network_update: None,
1170                         payment_failed_permanently: false,
1171                         all_paths_failed: false,
1172                         path: vec![],
1173                         short_channel_id: None,
1174                         retry: Some(retry_data),
1175                 };
1176                 invoice_payer.handle_event(&event);
1177                 assert_eq!(*event_handled.borrow(), true);
1178                 assert_eq!(*payer.attempts.borrow(), 1);
1179         }
1180
1181         #[test]
1182         fn fails_paying_invoice_after_retry_error() {
1183                 let event_handled = core::cell::RefCell::new(false);
1184                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1185
1186                 let payment_preimage = PaymentPreimage([1; 32]);
1187                 let invoice = invoice(payment_preimage);
1188                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
1189
1190                 let payer = TestPayer::new()
1191                         .fails_on_attempt(2)
1192                         .expect_send(Amount::ForInvoice(final_value_msat))
1193                         .expect_send(Amount::OnRetry(final_value_msat / 2));
1194                 let router = TestRouter::new(TestScorer::new());
1195                 let logger = TestLogger::new();
1196                 let invoice_payer =
1197                         InvoicePayer::new(&payer, router, &logger, event_handler, Retry::Attempts(2));
1198
1199                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
1200                 assert_eq!(*payer.attempts.borrow(), 1);
1201
1202                 let event = Event::PaymentPathFailed {
1203                         payment_id,
1204                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
1205                         network_update: None,
1206                         payment_failed_permanently: false,
1207                         all_paths_failed: false,
1208                         path: TestRouter::path_for_value(final_value_msat / 2),
1209                         short_channel_id: None,
1210                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
1211                 };
1212                 invoice_payer.handle_event(&event);
1213                 assert_eq!(*event_handled.borrow(), true);
1214                 assert_eq!(*payer.attempts.borrow(), 2);
1215         }
1216
1217         #[test]
1218         fn fails_paying_invoice_after_rejected_by_payee() {
1219                 let event_handled = core::cell::RefCell::new(false);
1220                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1221
1222                 let payment_preimage = PaymentPreimage([1; 32]);
1223                 let invoice = invoice(payment_preimage);
1224                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
1225
1226                 let payer = TestPayer::new().expect_send(Amount::ForInvoice(final_value_msat));
1227                 let router = TestRouter::new(TestScorer::new());
1228                 let logger = TestLogger::new();
1229                 let invoice_payer =
1230                         InvoicePayer::new(&payer, router, &logger, event_handler, Retry::Attempts(2));
1231
1232                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
1233                 assert_eq!(*payer.attempts.borrow(), 1);
1234
1235                 let event = Event::PaymentPathFailed {
1236                         payment_id,
1237                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
1238                         network_update: None,
1239                         payment_failed_permanently: true,
1240                         all_paths_failed: false,
1241                         path: vec![],
1242                         short_channel_id: None,
1243                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
1244                 };
1245                 invoice_payer.handle_event(&event);
1246                 assert_eq!(*event_handled.borrow(), true);
1247                 assert_eq!(*payer.attempts.borrow(), 1);
1248         }
1249
1250         #[test]
1251         fn fails_repaying_invoice_with_pending_payment() {
1252                 let event_handled = core::cell::RefCell::new(false);
1253                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1254
1255                 let payment_preimage = PaymentPreimage([1; 32]);
1256                 let invoice = invoice(payment_preimage);
1257                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
1258
1259                 let payer = TestPayer::new()
1260                         .expect_send(Amount::ForInvoice(final_value_msat))
1261                         .expect_send(Amount::ForInvoice(final_value_msat));
1262                 let router = TestRouter::new(TestScorer::new());
1263                 let logger = TestLogger::new();
1264                 let invoice_payer =
1265                         InvoicePayer::new(&payer, router, &logger, event_handler, Retry::Attempts(0));
1266
1267                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
1268
1269                 // Cannot repay an invoice pending payment.
1270                 match invoice_payer.pay_invoice(&invoice) {
1271                         Err(PaymentError::Invoice("payment pending")) => {},
1272                         Err(_) => panic!("unexpected error"),
1273                         Ok(_) => panic!("expected invoice error"),
1274                 }
1275
1276                 // Can repay an invoice once cleared from cache.
1277                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
1278                 invoice_payer.remove_cached_payment(&payment_hash);
1279                 assert!(invoice_payer.pay_invoice(&invoice).is_ok());
1280
1281                 // Cannot retry paying an invoice if cleared from cache.
1282                 invoice_payer.remove_cached_payment(&payment_hash);
1283                 let event = Event::PaymentPathFailed {
1284                         payment_id,
1285                         payment_hash,
1286                         network_update: None,
1287                         payment_failed_permanently: false,
1288                         all_paths_failed: false,
1289                         path: vec![],
1290                         short_channel_id: None,
1291                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
1292                 };
1293                 invoice_payer.handle_event(&event);
1294                 assert_eq!(*event_handled.borrow(), true);
1295         }
1296
1297         #[test]
1298         fn fails_paying_invoice_with_routing_errors() {
1299                 let payer = TestPayer::new();
1300                 let router = FailingRouter {};
1301                 let logger = TestLogger::new();
1302                 let invoice_payer =
1303                         InvoicePayer::new(&payer, router, &logger, |_: &_| {}, Retry::Attempts(0));
1304
1305                 let payment_preimage = PaymentPreimage([1; 32]);
1306                 let invoice = invoice(payment_preimage);
1307                 match invoice_payer.pay_invoice(&invoice) {
1308                         Err(PaymentError::Routing(_)) => {},
1309                         Err(_) => panic!("unexpected error"),
1310                         Ok(_) => panic!("expected routing error"),
1311                 }
1312         }
1313
1314         #[test]
1315         fn fails_paying_invoice_with_sending_errors() {
1316                 let payment_preimage = PaymentPreimage([1; 32]);
1317                 let invoice = invoice(payment_preimage);
1318                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
1319
1320                 let payer = TestPayer::new()
1321                         .fails_on_attempt(1)
1322                         .expect_send(Amount::ForInvoice(final_value_msat));
1323                 let router = TestRouter::new(TestScorer::new());
1324                 let logger = TestLogger::new();
1325                 let invoice_payer =
1326                         InvoicePayer::new(&payer, router, &logger, |_: &_| {}, Retry::Attempts(0));
1327
1328                 match invoice_payer.pay_invoice(&invoice) {
1329                         Err(PaymentError::Sending(_)) => {},
1330                         Err(_) => panic!("unexpected error"),
1331                         Ok(_) => panic!("expected sending error"),
1332                 }
1333         }
1334
1335         #[test]
1336         fn pays_zero_value_invoice_using_amount() {
1337                 let event_handled = core::cell::RefCell::new(false);
1338                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1339
1340                 let payment_preimage = PaymentPreimage([1; 32]);
1341                 let invoice = zero_value_invoice(payment_preimage);
1342                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
1343                 let final_value_msat = 100;
1344
1345                 let payer = TestPayer::new().expect_send(Amount::ForInvoice(final_value_msat));
1346                 let router = TestRouter::new(TestScorer::new());
1347                 let logger = TestLogger::new();
1348                 let invoice_payer =
1349                         InvoicePayer::new(&payer, router, &logger, event_handler, Retry::Attempts(0));
1350
1351                 let payment_id =
1352                         Some(invoice_payer.pay_zero_value_invoice(&invoice, final_value_msat).unwrap());
1353                 assert_eq!(*payer.attempts.borrow(), 1);
1354
1355                 invoice_payer.handle_event(&Event::PaymentSent {
1356                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
1357                 });
1358                 assert_eq!(*event_handled.borrow(), true);
1359                 assert_eq!(*payer.attempts.borrow(), 1);
1360         }
1361
1362         #[test]
1363         fn fails_paying_zero_value_invoice_with_amount() {
1364                 let event_handled = core::cell::RefCell::new(false);
1365                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1366
1367                 let payer = TestPayer::new();
1368                 let router = TestRouter::new(TestScorer::new());
1369                 let logger = TestLogger::new();
1370                 let invoice_payer =
1371                         InvoicePayer::new(&payer, router,  &logger, event_handler, Retry::Attempts(0));
1372
1373                 let payment_preimage = PaymentPreimage([1; 32]);
1374                 let invoice = invoice(payment_preimage);
1375
1376                 // Cannot repay an invoice pending payment.
1377                 match invoice_payer.pay_zero_value_invoice(&invoice, 100) {
1378                         Err(PaymentError::Invoice("amount unexpected")) => {},
1379                         Err(_) => panic!("unexpected error"),
1380                         Ok(_) => panic!("expected invoice error"),
1381                 }
1382         }
1383
1384         #[test]
1385         fn pays_pubkey_with_amount() {
1386                 let event_handled = core::cell::RefCell::new(false);
1387                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1388
1389                 let pubkey = pubkey();
1390                 let payment_preimage = PaymentPreimage([1; 32]);
1391                 let payment_hash = PaymentHash(Sha256::hash(&payment_preimage.0).into_inner());
1392                 let final_value_msat = 100;
1393                 let final_cltv_expiry_delta = 42;
1394
1395                 let payer = TestPayer::new()
1396                         .expect_send(Amount::Spontaneous(final_value_msat))
1397                         .expect_send(Amount::OnRetry(final_value_msat));
1398                 let router = TestRouter::new(TestScorer::new());
1399                 let logger = TestLogger::new();
1400                 let invoice_payer =
1401                         InvoicePayer::new(&payer, router, &logger, event_handler, Retry::Attempts(2));
1402
1403                 let payment_id = Some(invoice_payer.pay_pubkey(
1404                                 pubkey, payment_preimage, final_value_msat, final_cltv_expiry_delta
1405                         ).unwrap());
1406                 assert_eq!(*payer.attempts.borrow(), 1);
1407
1408                 let retry = RouteParameters {
1409                         payment_params: PaymentParameters::for_keysend(pubkey),
1410                         final_value_msat,
1411                         final_cltv_expiry_delta,
1412                 };
1413                 let event = Event::PaymentPathFailed {
1414                         payment_id,
1415                         payment_hash,
1416                         network_update: None,
1417                         payment_failed_permanently: false,
1418                         all_paths_failed: false,
1419                         path: vec![],
1420                         short_channel_id: None,
1421                         retry: Some(retry),
1422                 };
1423                 invoice_payer.handle_event(&event);
1424                 assert_eq!(*event_handled.borrow(), false);
1425                 assert_eq!(*payer.attempts.borrow(), 2);
1426
1427                 invoice_payer.handle_event(&Event::PaymentSent {
1428                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
1429                 });
1430                 assert_eq!(*event_handled.borrow(), true);
1431                 assert_eq!(*payer.attempts.borrow(), 2);
1432         }
1433
1434         #[test]
1435         fn scores_failed_channel() {
1436                 let event_handled = core::cell::RefCell::new(false);
1437                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1438
1439                 let payment_preimage = PaymentPreimage([1; 32]);
1440                 let invoice = invoice(payment_preimage);
1441                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
1442                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
1443                 let path = TestRouter::path_for_value(final_value_msat);
1444                 let short_channel_id = Some(path[0].short_channel_id);
1445
1446                 // Expect that scorer is given short_channel_id upon handling the event.
1447                 let payer = TestPayer::new()
1448                         .expect_send(Amount::ForInvoice(final_value_msat))
1449                         .expect_send(Amount::OnRetry(final_value_msat / 2));
1450                 let scorer = TestScorer::new().expect(TestResult::PaymentFailure {
1451                         path: path.clone(), short_channel_id: path[0].short_channel_id,
1452                 });
1453                 let router = TestRouter::new(scorer);
1454                 let logger = TestLogger::new();
1455                 let invoice_payer =
1456                         InvoicePayer::new(&payer, router, &logger, event_handler, Retry::Attempts(2));
1457
1458                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
1459                 let event = Event::PaymentPathFailed {
1460                         payment_id,
1461                         payment_hash,
1462                         network_update: None,
1463                         payment_failed_permanently: false,
1464                         all_paths_failed: false,
1465                         path,
1466                         short_channel_id,
1467                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
1468                 };
1469                 invoice_payer.handle_event(&event);
1470         }
1471
1472         #[test]
1473         fn scores_successful_channels() {
1474                 let event_handled = core::cell::RefCell::new(false);
1475                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1476
1477                 let payment_preimage = PaymentPreimage([1; 32]);
1478                 let invoice = invoice(payment_preimage);
1479                 let payment_hash = Some(PaymentHash(invoice.payment_hash().clone().into_inner()));
1480                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
1481                 let route = TestRouter::route_for_value(final_value_msat);
1482
1483                 // Expect that scorer is given short_channel_id upon handling the event.
1484                 let payer = TestPayer::new().expect_send(Amount::ForInvoice(final_value_msat));
1485                 let scorer = TestScorer::new()
1486                         .expect(TestResult::PaymentSuccess { path: route.paths[0].clone() })
1487                         .expect(TestResult::PaymentSuccess { path: route.paths[1].clone() });
1488                 let router = TestRouter::new(scorer);
1489                 let logger = TestLogger::new();
1490                 let invoice_payer =
1491                         InvoicePayer::new(&payer, router, &logger, event_handler, Retry::Attempts(2));
1492
1493                 let payment_id = invoice_payer.pay_invoice(&invoice).unwrap();
1494                 let event = Event::PaymentPathSuccessful {
1495                         payment_id, payment_hash, path: route.paths[0].clone()
1496                 };
1497                 invoice_payer.handle_event(&event);
1498                 let event = Event::PaymentPathSuccessful {
1499                         payment_id, payment_hash, path: route.paths[1].clone()
1500                 };
1501                 invoice_payer.handle_event(&event);
1502         }
1503
1504         #[test]
1505         fn generates_correct_inflight_map_data() {
1506                 let event_handled = core::cell::RefCell::new(false);
1507                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1508
1509                 let payment_preimage = PaymentPreimage([1; 32]);
1510                 let invoice = invoice(payment_preimage);
1511                 let payment_hash = Some(PaymentHash(invoice.payment_hash().clone().into_inner()));
1512                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
1513
1514                 let payer = TestPayer::new().expect_send(Amount::ForInvoice(final_value_msat));
1515                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
1516                 let route = TestRouter::route_for_value(final_value_msat);
1517                 let router = TestRouter::new(TestScorer::new());
1518                 let logger = TestLogger::new();
1519                 let invoice_payer =
1520                         InvoicePayer::new(&payer, router, &logger, event_handler, Retry::Attempts(0));
1521
1522                 let payment_id = invoice_payer.pay_invoice(&invoice).unwrap();
1523
1524                 let inflight_map = invoice_payer.create_inflight_map();
1525                 // First path check
1526                 assert_eq!(inflight_map.0.get(&(0, false)).unwrap().clone(), 94);
1527                 assert_eq!(inflight_map.0.get(&(1, true)).unwrap().clone(), 84);
1528                 assert_eq!(inflight_map.0.get(&(2, false)).unwrap().clone(), 64);
1529
1530                 // Second path check
1531                 assert_eq!(inflight_map.0.get(&(3, false)).unwrap().clone(), 74);
1532                 assert_eq!(inflight_map.0.get(&(4, false)).unwrap().clone(), 64);
1533
1534                 invoice_payer.handle_event(&Event::PaymentPathSuccessful {
1535                         payment_id, payment_hash, path: route.paths[0].clone()
1536                 });
1537
1538                 let inflight_map = invoice_payer.create_inflight_map();
1539
1540                 assert_eq!(inflight_map.0.get(&(0, false)), None);
1541                 assert_eq!(inflight_map.0.get(&(1, true)), None);
1542                 assert_eq!(inflight_map.0.get(&(2, false)), None);
1543
1544                 // Second path should still be inflight
1545                 assert_eq!(inflight_map.0.get(&(3, false)).unwrap().clone(), 74);
1546                 assert_eq!(inflight_map.0.get(&(4, false)).unwrap().clone(), 64)
1547         }
1548
1549         #[test]
1550         fn considers_inflight_htlcs_between_invoice_payments_when_path_succeeds() {
1551                 // First, let's just send a payment through, but only make sure one of the path completes
1552                 let event_handled = core::cell::RefCell::new(false);
1553                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1554
1555                 let payment_preimage = PaymentPreimage([1; 32]);
1556                 let payment_invoice = invoice(payment_preimage);
1557                 let payment_hash = Some(PaymentHash(payment_invoice.payment_hash().clone().into_inner()));
1558                 let final_value_msat = payment_invoice.amount_milli_satoshis().unwrap();
1559
1560                 let payer = TestPayer::new()
1561                         .expect_send(Amount::ForInvoice(final_value_msat))
1562                         .expect_send(Amount::ForInvoice(final_value_msat));
1563                 let final_value_msat = payment_invoice.amount_milli_satoshis().unwrap();
1564                 let route = TestRouter::route_for_value(final_value_msat);
1565                 let scorer = TestScorer::new()
1566                         // 1st invoice, 1st path
1567                         .expect_usage(ChannelUsage { amount_msat: 64, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown } )
1568                         .expect_usage(ChannelUsage { amount_msat: 84, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown } )
1569                         .expect_usage(ChannelUsage { amount_msat: 94, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown } )
1570                         // 1st invoice, 2nd path
1571                         .expect_usage(ChannelUsage { amount_msat: 64, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown } )
1572                         .expect_usage(ChannelUsage { amount_msat: 74, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown } )
1573                         // 2nd invoice, 1st path
1574                         .expect_usage(ChannelUsage { amount_msat: 64, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown } )
1575                         .expect_usage(ChannelUsage { amount_msat: 84, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown } )
1576                         .expect_usage(ChannelUsage { amount_msat: 94, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown } )
1577                         // 2nd invoice, 2nd path
1578                         .expect_usage(ChannelUsage { amount_msat: 64, inflight_htlc_msat: 64, effective_capacity: EffectiveCapacity::Unknown } )
1579                         .expect_usage(ChannelUsage { amount_msat: 74, inflight_htlc_msat: 74, effective_capacity: EffectiveCapacity::Unknown } );
1580                 let router = TestRouter::new(scorer);
1581                 let logger = TestLogger::new();
1582                 let invoice_payer =
1583                         InvoicePayer::new(&payer, router, &logger, event_handler, Retry::Attempts(0));
1584
1585                 // Succeed 1st path, leave 2nd path inflight
1586                 let payment_id = invoice_payer.pay_invoice(&payment_invoice).unwrap();
1587                 invoice_payer.handle_event(&Event::PaymentPathSuccessful {
1588                         payment_id, payment_hash, path: route.paths[0].clone()
1589                 });
1590
1591                 // Let's pay a second invoice that will be using the same path. This should trigger the
1592                 // assertions that expect the last 4 ChannelUsage values above where TestScorer is initialized.
1593                 // Particularly, the 2nd path of the 1st payment, since it is not yet complete, should still
1594                 // have 64 msats inflight for paths considering the channel with scid of 1.
1595                 let payment_preimage_2 = PaymentPreimage([2; 32]);
1596                 let payment_invoice_2 = invoice(payment_preimage_2);
1597                 invoice_payer.pay_invoice(&payment_invoice_2).unwrap();
1598         }
1599
1600         #[test]
1601         fn considers_inflight_htlcs_between_retries() {
1602                 // First, let's just send a payment through, but only make sure one of the path completes
1603                 let event_handled = core::cell::RefCell::new(false);
1604                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1605
1606                 let payment_preimage = PaymentPreimage([1; 32]);
1607                 let payment_invoice = invoice(payment_preimage);
1608                 let payment_hash = PaymentHash(payment_invoice.payment_hash().clone().into_inner());
1609                 let final_value_msat = payment_invoice.amount_milli_satoshis().unwrap();
1610
1611                 let payer = TestPayer::new()
1612                         .expect_send(Amount::ForInvoice(final_value_msat))
1613                         .expect_send(Amount::OnRetry(final_value_msat / 2))
1614                         .expect_send(Amount::OnRetry(final_value_msat / 4));
1615                 let final_value_msat = payment_invoice.amount_milli_satoshis().unwrap();
1616                 let scorer = TestScorer::new()
1617                         // 1st invoice, 1st path
1618                         .expect_usage(ChannelUsage { amount_msat: 64, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown } )
1619                         .expect_usage(ChannelUsage { amount_msat: 84, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown } )
1620                         .expect_usage(ChannelUsage { amount_msat: 94, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown } )
1621                         // 1st invoice, 2nd path
1622                         .expect_usage(ChannelUsage { amount_msat: 64, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown } )
1623                         .expect_usage(ChannelUsage { amount_msat: 74, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown } )
1624                         // Retry 1, 1st path
1625                         .expect_usage(ChannelUsage { amount_msat: 32, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown } )
1626                         .expect_usage(ChannelUsage { amount_msat: 52, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown } )
1627                         .expect_usage(ChannelUsage { amount_msat: 62, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown } )
1628                         // Retry 1, 2nd path
1629                         .expect_usage(ChannelUsage { amount_msat: 32, inflight_htlc_msat: 64, effective_capacity: EffectiveCapacity::Unknown } )
1630                         .expect_usage(ChannelUsage { amount_msat: 42, inflight_htlc_msat: 64 + 10, effective_capacity: EffectiveCapacity::Unknown } )
1631                         // Retry 2, 1st path
1632                         .expect_usage(ChannelUsage { amount_msat: 16, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown } )
1633                         .expect_usage(ChannelUsage { amount_msat: 36, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown } )
1634                         .expect_usage(ChannelUsage { amount_msat: 46, inflight_htlc_msat: 0, effective_capacity: EffectiveCapacity::Unknown } )
1635                         // Retry 2, 2nd path
1636                         .expect_usage(ChannelUsage { amount_msat: 16, inflight_htlc_msat: 64 + 32, effective_capacity: EffectiveCapacity::Unknown } )
1637                         .expect_usage(ChannelUsage { amount_msat: 26, inflight_htlc_msat: 74 + 32 + 10, effective_capacity: EffectiveCapacity::Unknown } );
1638                 let router = TestRouter::new(scorer);
1639                 let logger = TestLogger::new();
1640                 let invoice_payer =
1641                         InvoicePayer::new(&payer, router, &logger, event_handler, Retry::Attempts(2));
1642
1643                 // Fail 1st path, leave 2nd path inflight
1644                 let payment_id = Some(invoice_payer.pay_invoice(&payment_invoice).unwrap());
1645                 invoice_payer.handle_event(&Event::PaymentPathFailed {
1646                         payment_id,
1647                         payment_hash,
1648                         network_update: None,
1649                         payment_failed_permanently: false,
1650                         all_paths_failed: false,
1651                         path: TestRouter::path_for_value(final_value_msat),
1652                         short_channel_id: None,
1653                         retry: Some(TestRouter::retry_for_invoice(&payment_invoice)),
1654                 });
1655
1656                 // Fails again the 1st path of our retry
1657                 invoice_payer.handle_event(&Event::PaymentPathFailed {
1658                         payment_id,
1659                         payment_hash,
1660                         network_update: None,
1661                         payment_failed_permanently: false,
1662                         all_paths_failed: false,
1663                         path: TestRouter::path_for_value(final_value_msat / 2),
1664                         short_channel_id: None,
1665                         retry: Some(RouteParameters {
1666                                 final_value_msat: final_value_msat / 4,
1667                                 ..TestRouter::retry_for_invoice(&payment_invoice)
1668                         }),
1669                 });
1670         }
1671
1672         #[test]
1673         fn accounts_for_some_inflight_htlcs_sent_during_partial_failure() {
1674                 let event_handled = core::cell::RefCell::new(false);
1675                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1676
1677                 let payment_preimage = PaymentPreimage([1; 32]);
1678                 let invoice_to_pay = invoice(payment_preimage);
1679                 let final_value_msat = invoice_to_pay.amount_milli_satoshis().unwrap();
1680
1681                 let retry = TestRouter::retry_for_invoice(&invoice_to_pay);
1682                 let payer = TestPayer::new()
1683                         .fails_with_partial_failure(
1684                                 retry.clone(), OnAttempt(1),
1685                                 Some(vec![
1686                                         Err(ChannelUnavailable { err: "abc".to_string() }), Err(MonitorUpdateFailed)
1687                                 ]))
1688                         .expect_send(Amount::ForInvoice(final_value_msat));
1689
1690                 let router = TestRouter::new(TestScorer::new());
1691                 let logger = TestLogger::new();
1692                 let invoice_payer =
1693                         InvoicePayer::new(&payer, router, &logger, event_handler, Retry::Attempts(0));
1694
1695                 invoice_payer.pay_invoice(&invoice_to_pay).unwrap();
1696                 let inflight_map = invoice_payer.create_inflight_map();
1697
1698                 // Only the second path, which failed with `MonitorUpdateFailed` should be added to our
1699                 // inflight map because retries are disabled.
1700                 assert_eq!(inflight_map.0.len(), 2);
1701         }
1702
1703         #[test]
1704         fn accounts_for_all_inflight_htlcs_sent_during_partial_failure() {
1705                 let event_handled = core::cell::RefCell::new(false);
1706                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
1707
1708                 let payment_preimage = PaymentPreimage([1; 32]);
1709                 let invoice_to_pay = invoice(payment_preimage);
1710                 let final_value_msat = invoice_to_pay.amount_milli_satoshis().unwrap();
1711
1712                 let retry = TestRouter::retry_for_invoice(&invoice_to_pay);
1713                 let payer = TestPayer::new()
1714                         .fails_with_partial_failure(
1715                                 retry.clone(), OnAttempt(1),
1716                                 Some(vec![
1717                                         Ok(()), Err(MonitorUpdateFailed)
1718                                 ]))
1719                         .expect_send(Amount::ForInvoice(final_value_msat));
1720
1721                 let router = TestRouter::new(TestScorer::new());
1722                 let logger = TestLogger::new();
1723                 let invoice_payer =
1724                         InvoicePayer::new(&payer, router, &logger, event_handler, Retry::Attempts(0));
1725
1726                 invoice_payer.pay_invoice(&invoice_to_pay).unwrap();
1727                 let inflight_map = invoice_payer.create_inflight_map();
1728
1729                 // All paths successful, hence we check of the existence of all 5 hops.
1730                 assert_eq!(inflight_map.0.len(), 5);
1731         }
1732
1733         struct TestRouter {
1734                 scorer: RefCell<TestScorer>,
1735         }
1736
1737         impl TestRouter {
1738                 fn new(scorer: TestScorer) -> Self {
1739                         TestRouter { scorer: RefCell::new(scorer) }
1740                 }
1741
1742                 fn route_for_value(final_value_msat: u64) -> Route {
1743                         Route {
1744                                 paths: vec![
1745                                         vec![
1746                                                 RouteHop {
1747                                                         pubkey: PublicKey::from_slice(&hex::decode("02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619").unwrap()[..]).unwrap(),
1748                                                         channel_features: ChannelFeatures::empty(),
1749                                                         node_features: NodeFeatures::empty(),
1750                                                         short_channel_id: 0,
1751                                                         fee_msat: 10,
1752                                                         cltv_expiry_delta: 0
1753                                                 },
1754                                                 RouteHop {
1755                                                         pubkey: PublicKey::from_slice(&hex::decode("0324653eac434488002cc06bbfb7f10fe18991e35f9fe4302dbea6d2353dc0ab1c").unwrap()[..]).unwrap(),
1756                                                         channel_features: ChannelFeatures::empty(),
1757                                                         node_features: NodeFeatures::empty(),
1758                                                         short_channel_id: 1,
1759                                                         fee_msat: 20,
1760                                                         cltv_expiry_delta: 0
1761                                                 },
1762                                                 RouteHop {
1763                                                         pubkey: PublicKey::from_slice(&hex::decode("027f31ebc5462c1fdce1b737ecff52d37d75dea43ce11c74d25aa297165faa2007").unwrap()[..]).unwrap(),
1764                                                         channel_features: ChannelFeatures::empty(),
1765                                                         node_features: NodeFeatures::empty(),
1766                                                         short_channel_id: 2,
1767                                                         fee_msat: final_value_msat / 2,
1768                                                         cltv_expiry_delta: 0
1769                                                 },
1770                                         ],
1771                                         vec![
1772                                                 RouteHop {
1773                                                         pubkey: PublicKey::from_slice(&hex::decode("029e03a901b85534ff1e92c43c74431f7ce72046060fcf7a95c37e148f78c77255").unwrap()[..]).unwrap(),
1774                                                         channel_features: ChannelFeatures::empty(),
1775                                                         node_features: NodeFeatures::empty(),
1776                                                         short_channel_id: 3,
1777                                                         fee_msat: 10,
1778                                                         cltv_expiry_delta: 144
1779                                                 },
1780                                                 RouteHop {
1781                                                         pubkey: PublicKey::from_slice(&hex::decode("027f31ebc5462c1fdce1b737ecff52d37d75dea43ce11c74d25aa297165faa2007").unwrap()[..]).unwrap(),
1782                                                         channel_features: ChannelFeatures::empty(),
1783                                                         node_features: NodeFeatures::empty(),
1784                                                         short_channel_id: 4,
1785                                                         fee_msat: final_value_msat / 2,
1786                                                         cltv_expiry_delta: 144
1787                                                 }
1788                                         ],
1789                                 ],
1790                                 payment_params: None,
1791                         }
1792                 }
1793
1794                 fn path_for_value(final_value_msat: u64) -> Vec<RouteHop> {
1795                         TestRouter::route_for_value(final_value_msat).paths[0].clone()
1796                 }
1797
1798                 fn retry_for_invoice(invoice: &Invoice) -> RouteParameters {
1799                         let mut payment_params = PaymentParameters::from_node_id(invoice.recover_payee_pub_key())
1800                                 .with_expiry_time(expiry_time_from_unix_epoch(invoice).as_secs())
1801                                 .with_route_hints(invoice.route_hints());
1802                         if let Some(features) = invoice.features() {
1803                                 payment_params = payment_params.with_features(features.clone());
1804                         }
1805                         let final_value_msat = invoice.amount_milli_satoshis().unwrap() / 2;
1806                         RouteParameters {
1807                                 payment_params,
1808                                 final_value_msat,
1809                                 final_cltv_expiry_delta: invoice.min_final_cltv_expiry() as u32,
1810                         }
1811                 }
1812         }
1813
1814         impl Router for TestRouter {
1815                 fn find_route(
1816                         &self, payer: &PublicKey, route_params: &RouteParameters, _payment_hash: &PaymentHash,
1817                         _first_hops: Option<&[&ChannelDetails]>, inflight_htlcs: InFlightHtlcs
1818                 ) -> Result<Route, LightningError> {
1819                         // Simulate calling the Scorer just as you would in find_route
1820                         let route = Self::route_for_value(route_params.final_value_msat);
1821                         let mut locked_scorer = self.scorer.lock();
1822                         let scorer = ScorerAccountingForInFlightHtlcs::new(locked_scorer.deref_mut(), inflight_htlcs);
1823                         for path in route.paths {
1824                                 let mut aggregate_msat = 0u64;
1825                                 for (idx, hop) in path.iter().rev().enumerate() {
1826                                         aggregate_msat += hop.fee_msat;
1827                                         let usage = ChannelUsage {
1828                                                 amount_msat: aggregate_msat,
1829                                                 inflight_htlc_msat: 0,
1830                                                 effective_capacity: EffectiveCapacity::Unknown,
1831                                         };
1832
1833                                         // Since the path is reversed, the last element in our iteration is the first
1834                                         // hop.
1835                                         if idx == path.len() - 1 {
1836                                                 scorer.channel_penalty_msat(hop.short_channel_id, &NodeId::from_pubkey(payer), &NodeId::from_pubkey(&hop.pubkey), usage);
1837                                         } else {
1838                                                 scorer.channel_penalty_msat(hop.short_channel_id, &NodeId::from_pubkey(&path[idx + 1].pubkey), &NodeId::from_pubkey(&hop.pubkey), usage);
1839                                         }
1840                                 }
1841                         }
1842
1843                         Ok(Route {
1844                                 payment_params: Some(route_params.payment_params.clone()), ..Self::route_for_value(route_params.final_value_msat)
1845                         })
1846                 }
1847
1848                 fn notify_payment_path_failed(&self, path: &[&RouteHop], short_channel_id: u64) {
1849                         self.scorer.lock().payment_path_failed(path, short_channel_id);
1850                 }
1851
1852                 fn notify_payment_path_successful(&self, path: &[&RouteHop]) {
1853                         self.scorer.lock().payment_path_successful(path);
1854                 }
1855
1856                 fn notify_payment_probe_successful(&self, path: &[&RouteHop]) {
1857                         self.scorer.lock().probe_successful(path);
1858                 }
1859
1860                 fn notify_payment_probe_failed(&self, path: &[&RouteHop], short_channel_id: u64) {
1861                         self.scorer.lock().probe_failed(path, short_channel_id);
1862                 }
1863         }
1864
1865         struct FailingRouter;
1866
1867         impl Router for FailingRouter {
1868                 fn find_route(
1869                         &self, _payer: &PublicKey, _params: &RouteParameters, _payment_hash: &PaymentHash,
1870                         _first_hops: Option<&[&ChannelDetails]>, _inflight_htlcs: InFlightHtlcs
1871                 ) -> Result<Route, LightningError> {
1872                         Err(LightningError { err: String::new(), action: ErrorAction::IgnoreError })
1873                 }
1874
1875                 fn notify_payment_path_failed(&self, _path: &[&RouteHop], _short_channel_id: u64) {}
1876
1877                 fn notify_payment_path_successful(&self, _path: &[&RouteHop]) {}
1878
1879                 fn notify_payment_probe_successful(&self, _path: &[&RouteHop]) {}
1880
1881                 fn notify_payment_probe_failed(&self, _path: &[&RouteHop], _short_channel_id: u64) {}
1882         }
1883
1884         struct TestScorer {
1885                 event_expectations: Option<VecDeque<TestResult>>,
1886                 scorer_expectations: RefCell<Option<VecDeque<ChannelUsage>>>,
1887         }
1888
1889         #[derive(Debug)]
1890         enum TestResult {
1891                 PaymentFailure { path: Vec<RouteHop>, short_channel_id: u64 },
1892                 PaymentSuccess { path: Vec<RouteHop> },
1893         }
1894
1895         impl TestScorer {
1896                 fn new() -> Self {
1897                         Self {
1898                                 event_expectations: None,
1899                                 scorer_expectations: RefCell::new(None),
1900                         }
1901                 }
1902
1903                 fn expect(mut self, expectation: TestResult) -> Self {
1904                         self.event_expectations.get_or_insert_with(|| VecDeque::new()).push_back(expectation);
1905                         self
1906                 }
1907
1908                 fn expect_usage(self, expectation: ChannelUsage) -> Self {
1909                         self.scorer_expectations.borrow_mut().get_or_insert_with(|| VecDeque::new()).push_back(expectation);
1910                         self
1911                 }
1912         }
1913
1914         #[cfg(c_bindings)]
1915         impl lightning::util::ser::Writeable for TestScorer {
1916                 fn write<W: lightning::util::ser::Writer>(&self, _: &mut W) -> Result<(), std::io::Error> { unreachable!(); }
1917         }
1918
1919         impl Score for TestScorer {
1920                 fn channel_penalty_msat(
1921                         &self, _short_channel_id: u64, _source: &NodeId, _target: &NodeId, usage: ChannelUsage
1922                 ) -> u64 {
1923                         if let Some(scorer_expectations) = self.scorer_expectations.borrow_mut().as_mut() {
1924                                 match scorer_expectations.pop_front() {
1925                                         Some(expectation) => {
1926                                                 assert_eq!(expectation.amount_msat, usage.amount_msat);
1927                                                 assert_eq!(expectation.inflight_htlc_msat, usage.inflight_htlc_msat);
1928                                         },
1929                                         None => {},
1930                                 }
1931                         }
1932                         0
1933                 }
1934
1935                 fn payment_path_failed(&mut self, actual_path: &[&RouteHop], actual_short_channel_id: u64) {
1936                         if let Some(expectations) = &mut self.event_expectations {
1937                                 match expectations.pop_front() {
1938                                         Some(TestResult::PaymentFailure { path, short_channel_id }) => {
1939                                                 assert_eq!(actual_path, &path.iter().collect::<Vec<_>>()[..]);
1940                                                 assert_eq!(actual_short_channel_id, short_channel_id);
1941                                         },
1942                                         Some(TestResult::PaymentSuccess { path }) => {
1943                                                 panic!("Unexpected successful payment path: {:?}", path)
1944                                         },
1945                                         None => panic!("Unexpected notify_payment_path_failed call: {:?}", actual_path),
1946                                 }
1947                         }
1948                 }
1949
1950                 fn payment_path_successful(&mut self, actual_path: &[&RouteHop]) {
1951                         if let Some(expectations) = &mut self.event_expectations {
1952                                 match expectations.pop_front() {
1953                                         Some(TestResult::PaymentFailure { path, .. }) => {
1954                                                 panic!("Unexpected payment path failure: {:?}", path)
1955                                         },
1956                                         Some(TestResult::PaymentSuccess { path }) => {
1957                                                 assert_eq!(actual_path, &path.iter().collect::<Vec<_>>()[..]);
1958                                         },
1959                                         None => panic!("Unexpected notify_payment_path_successful call: {:?}", actual_path),
1960                                 }
1961                         }
1962                 }
1963
1964                 fn probe_failed(&mut self, actual_path: &[&RouteHop], _: u64) {
1965                         if let Some(expectations) = &mut self.event_expectations {
1966                                 match expectations.pop_front() {
1967                                         Some(TestResult::PaymentFailure { path, .. }) => {
1968                                                 panic!("Unexpected failed payment path: {:?}", path)
1969                                         },
1970                                         Some(TestResult::PaymentSuccess { path }) => {
1971                                                 panic!("Unexpected successful payment path: {:?}", path)
1972                                         },
1973                                         None => panic!("Unexpected notify_payment_path_failed call: {:?}", actual_path),
1974                                 }
1975                         }
1976                 }
1977                 fn probe_successful(&mut self, actual_path: &[&RouteHop]) {
1978                         if let Some(expectations) = &mut self.event_expectations {
1979                                 match expectations.pop_front() {
1980                                         Some(TestResult::PaymentFailure { path, .. }) => {
1981                                                 panic!("Unexpected payment path failure: {:?}", path)
1982                                         },
1983                                         Some(TestResult::PaymentSuccess { path }) => {
1984                                                 panic!("Unexpected successful payment path: {:?}", path)
1985                                         },
1986                                         None => panic!("Unexpected notify_payment_path_successful call: {:?}", actual_path),
1987                                 }
1988                         }
1989                 }
1990         }
1991
1992         impl Drop for TestScorer {
1993                 fn drop(&mut self) {
1994                         if std::thread::panicking() {
1995                                 return;
1996                         }
1997
1998                         if let Some(event_expectations) = &self.event_expectations {
1999                                 if !event_expectations.is_empty() {
2000                                         panic!("Unsatisfied event expectations: {:?}", event_expectations);
2001                                 }
2002                         }
2003
2004                         if let Some(scorer_expectations) = self.scorer_expectations.borrow().as_ref() {
2005                                 if !scorer_expectations.is_empty() {
2006                                         panic!("Unsatisfied scorer expectations: {:?}", scorer_expectations)
2007                                 }
2008                         }
2009                 }
2010         }
2011
2012         struct TestPayer {
2013                 expectations: core::cell::RefCell<VecDeque<Amount>>,
2014                 attempts: core::cell::RefCell<usize>,
2015                 failing_on_attempt: core::cell::RefCell<HashMap<usize, PaymentSendFailure>>,
2016         }
2017
2018         #[derive(Clone, Debug, PartialEq, Eq)]
2019         enum Amount {
2020                 ForInvoice(u64),
2021                 Spontaneous(u64),
2022                 OnRetry(u64),
2023         }
2024
2025         struct OnAttempt(usize);
2026
2027         impl TestPayer {
2028                 fn new() -> Self {
2029                         Self {
2030                                 expectations: core::cell::RefCell::new(VecDeque::new()),
2031                                 attempts: core::cell::RefCell::new(0),
2032                                 failing_on_attempt: core::cell::RefCell::new(HashMap::new()),
2033                         }
2034                 }
2035
2036                 fn expect_send(self, value_msat: Amount) -> Self {
2037                         self.expectations.borrow_mut().push_back(value_msat);
2038                         self
2039                 }
2040
2041                 fn fails_on_attempt(self, attempt: usize) -> Self {
2042                         let failure = PaymentSendFailure::ParameterError(APIError::MonitorUpdateFailed);
2043                         self.fails_with(failure, OnAttempt(attempt))
2044                 }
2045
2046                 fn fails_with_partial_failure(self, retry: RouteParameters, attempt: OnAttempt, results: Option<Vec<Result<(), APIError>>>) -> Self {
2047                         self.fails_with(PaymentSendFailure::PartialFailure {
2048                                 results: results.unwrap_or(vec![]),
2049                                 failed_paths_retry: Some(retry),
2050                                 payment_id: PaymentId([1; 32]),
2051                         }, attempt)
2052                 }
2053
2054                 fn fails_with(self, failure: PaymentSendFailure, attempt: OnAttempt) -> Self {
2055                         self.failing_on_attempt.borrow_mut().insert(attempt.0, failure);
2056                         self
2057                 }
2058
2059                 fn check_attempts(&self) -> Result<PaymentId, PaymentSendFailure> {
2060                         let mut attempts = self.attempts.borrow_mut();
2061                         *attempts += 1;
2062
2063                         match self.failing_on_attempt.borrow_mut().remove(&*attempts) {
2064                                 Some(failure) => Err(failure),
2065                                 None => Ok(PaymentId([1; 32])),
2066                         }
2067                 }
2068
2069                 fn check_value_msats(&self, actual_value_msats: Amount) {
2070                         let expected_value_msats = self.expectations.borrow_mut().pop_front();
2071                         if let Some(expected_value_msats) = expected_value_msats {
2072                                 assert_eq!(actual_value_msats, expected_value_msats);
2073                         } else {
2074                                 panic!("Unexpected amount: {:?}", actual_value_msats);
2075                         }
2076                 }
2077         }
2078
2079         impl Drop for TestPayer {
2080                 fn drop(&mut self) {
2081                         if std::thread::panicking() {
2082                                 return;
2083                         }
2084
2085                         if !self.expectations.borrow().is_empty() {
2086                                 panic!("Unsatisfied payment expectations: {:?}", self.expectations.borrow());
2087                         }
2088                 }
2089         }
2090
2091         impl Payer for TestPayer {
2092                 fn node_id(&self) -> PublicKey {
2093                         let secp_ctx = Secp256k1::new();
2094                         PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap())
2095                 }
2096
2097                 fn first_hops(&self) -> Vec<ChannelDetails> {
2098                         Vec::new()
2099                 }
2100
2101                 fn send_payment(
2102                         &self, route: &Route, _payment_hash: PaymentHash,
2103                         _payment_secret: &Option<PaymentSecret>
2104                 ) -> Result<PaymentId, PaymentSendFailure> {
2105                         self.check_value_msats(Amount::ForInvoice(route.get_total_amount()));
2106                         self.check_attempts()
2107                 }
2108
2109                 fn send_spontaneous_payment(
2110                         &self, route: &Route, _payment_preimage: PaymentPreimage,
2111                 ) -> Result<PaymentId, PaymentSendFailure> {
2112                         self.check_value_msats(Amount::Spontaneous(route.get_total_amount()));
2113                         self.check_attempts()
2114                 }
2115
2116                 fn retry_payment(
2117                         &self, route: &Route, _payment_id: PaymentId
2118                 ) -> Result<(), PaymentSendFailure> {
2119                         self.check_value_msats(Amount::OnRetry(route.get_total_amount()));
2120                         self.check_attempts().map(|_| ())
2121                 }
2122
2123                 fn abandon_payment(&self, _payment_id: PaymentId) { }
2124         }
2125
2126         // *** Full Featured Functional Tests with a Real ChannelManager ***
2127         struct ManualRouter(RefCell<VecDeque<Result<Route, LightningError>>>);
2128
2129         impl Router for ManualRouter {
2130                 fn find_route(
2131                         &self, _payer: &PublicKey, _params: &RouteParameters, _payment_hash: &PaymentHash,
2132                         _first_hops: Option<&[&ChannelDetails]>, _inflight_htlcs: InFlightHtlcs
2133                 ) -> Result<Route, LightningError> {
2134                         self.0.borrow_mut().pop_front().unwrap()
2135                 }
2136
2137                 fn notify_payment_path_failed(&self, _path: &[&RouteHop], _short_channel_id: u64) {}
2138
2139                 fn notify_payment_path_successful(&self, _path: &[&RouteHop]) {}
2140
2141                 fn notify_payment_probe_successful(&self, _path: &[&RouteHop]) {}
2142
2143                 fn notify_payment_probe_failed(&self, _path: &[&RouteHop], _short_channel_id: u64) {}
2144         }
2145         impl ManualRouter {
2146                 fn expect_find_route(&self, result: Result<Route, LightningError>) {
2147                         self.0.borrow_mut().push_back(result);
2148                 }
2149         }
2150         impl Drop for ManualRouter {
2151                 fn drop(&mut self) {
2152                         if std::thread::panicking() {
2153                                 return;
2154                         }
2155                         assert!(self.0.borrow_mut().is_empty());
2156                 }
2157         }
2158
2159         #[test]
2160         fn retry_multi_path_single_failed_payment() {
2161                 // Tests that we can/will retry after a single path of an MPP payment failed immediately
2162                 let chanmon_cfgs = create_chanmon_cfgs(2);
2163                 let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
2164                 let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None, None]);
2165                 let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
2166
2167                 create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0, channelmanager::provided_init_features(), channelmanager::provided_init_features());
2168                 create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0, channelmanager::provided_init_features(), channelmanager::provided_init_features());
2169                 let chans = nodes[0].node.list_usable_channels();
2170                 let mut route = Route {
2171                         paths: vec![
2172                                 vec![RouteHop {
2173                                         pubkey: nodes[1].node.get_our_node_id(),
2174                                         node_features: channelmanager::provided_node_features(),
2175                                         short_channel_id: chans[0].short_channel_id.unwrap(),
2176                                         channel_features: channelmanager::provided_channel_features(),
2177                                         fee_msat: 10_000,
2178                                         cltv_expiry_delta: 100,
2179                                 }],
2180                                 vec![RouteHop {
2181                                         pubkey: nodes[1].node.get_our_node_id(),
2182                                         node_features: channelmanager::provided_node_features(),
2183                                         short_channel_id: chans[1].short_channel_id.unwrap(),
2184                                         channel_features: channelmanager::provided_channel_features(),
2185                                         fee_msat: 100_000_001, // Our default max-HTLC-value is 10% of the channel value, which this is one more than
2186                                         cltv_expiry_delta: 100,
2187                                 }],
2188                         ],
2189                         payment_params: Some(PaymentParameters::from_node_id(nodes[1].node.get_our_node_id())),
2190                 };
2191                 let router = ManualRouter(RefCell::new(VecDeque::new()));
2192                 router.expect_find_route(Ok(route.clone()));
2193                 // On retry, split the payment across both channels.
2194                 route.paths[0][0].fee_msat = 50_000_001;
2195                 route.paths[1][0].fee_msat = 50_000_000;
2196                 router.expect_find_route(Ok(route.clone()));
2197
2198                 let event_handler = |_: &_| { panic!(); };
2199                 let invoice_payer = InvoicePayer::new(nodes[0].node, router, nodes[0].logger, event_handler, Retry::Attempts(1));
2200
2201                 assert!(invoice_payer.pay_invoice(&create_invoice_from_channelmanager_and_duration_since_epoch(
2202                         &nodes[1].node, nodes[1].keys_manager, Currency::Bitcoin, Some(100_010_000), "Invoice".to_string(),
2203                         duration_since_epoch(), 3600).unwrap())
2204                         .is_ok());
2205                 let htlc_msgs = nodes[0].node.get_and_clear_pending_msg_events();
2206                 assert_eq!(htlc_msgs.len(), 2);
2207                 check_added_monitors!(nodes[0], 2);
2208         }
2209
2210         #[test]
2211         fn immediate_retry_on_failure() {
2212                 // Tests that we can/will retry immediately after a failure
2213                 let chanmon_cfgs = create_chanmon_cfgs(2);
2214                 let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
2215                 let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None, None]);
2216                 let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
2217
2218                 create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0, channelmanager::provided_init_features(), channelmanager::provided_init_features());
2219                 create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 1_000_000, 0, channelmanager::provided_init_features(), channelmanager::provided_init_features());
2220                 let chans = nodes[0].node.list_usable_channels();
2221                 let mut route = Route {
2222                         paths: vec![
2223                                 vec![RouteHop {
2224                                         pubkey: nodes[1].node.get_our_node_id(),
2225                                         node_features: channelmanager::provided_node_features(),
2226                                         short_channel_id: chans[0].short_channel_id.unwrap(),
2227                                         channel_features: channelmanager::provided_channel_features(),
2228                                         fee_msat: 100_000_001, // Our default max-HTLC-value is 10% of the channel value, which this is one more than
2229                                         cltv_expiry_delta: 100,
2230                                 }],
2231                         ],
2232                         payment_params: Some(PaymentParameters::from_node_id(nodes[1].node.get_our_node_id())),
2233                 };
2234                 let router = ManualRouter(RefCell::new(VecDeque::new()));
2235                 router.expect_find_route(Ok(route.clone()));
2236                 // On retry, split the payment across both channels.
2237                 route.paths.push(route.paths[0].clone());
2238                 route.paths[0][0].short_channel_id = chans[1].short_channel_id.unwrap();
2239                 route.paths[0][0].fee_msat = 50_000_000;
2240                 route.paths[1][0].fee_msat = 50_000_001;
2241                 router.expect_find_route(Ok(route.clone()));
2242
2243                 let event_handler = |_: &_| { panic!(); };
2244                 let invoice_payer = InvoicePayer::new(nodes[0].node, router, nodes[0].logger, event_handler, Retry::Attempts(1));
2245
2246                 assert!(invoice_payer.pay_invoice(&create_invoice_from_channelmanager_and_duration_since_epoch(
2247                         &nodes[1].node, nodes[1].keys_manager, Currency::Bitcoin, Some(100_010_000), "Invoice".to_string(),
2248                         duration_since_epoch(), 3600).unwrap())
2249                         .is_ok());
2250                 let htlc_msgs = nodes[0].node.get_and_clear_pending_msg_events();
2251                 assert_eq!(htlc_msgs.len(), 2);
2252                 check_added_monitors!(nodes[0], 2);
2253         }
2254
2255         #[test]
2256         fn no_extra_retries_on_back_to_back_fail() {
2257                 // In a previous release, we had a race where we may exceed the payment retry count if we
2258                 // get two failures in a row with the second having `all_paths_failed` set.
2259                 // Generally, when we give up trying to retry a payment, we don't know for sure what the
2260                 // current state of the ChannelManager event queue is. Specifically, we cannot be sure that
2261                 // there are not multiple additional `PaymentPathFailed` or even `PaymentSent` events
2262                 // pending which we will see later. Thus, when we previously removed the retry tracking map
2263                 // entry after a `all_paths_failed` `PaymentPathFailed` event, we may have dropped the
2264                 // retry entry even though more events for the same payment were still pending. This led to
2265                 // us retrying a payment again even though we'd already given up on it.
2266                 //
2267                 // We now have a separate event - `PaymentFailed` which indicates no HTLCs remain and which
2268                 // is used to remove the payment retry counter entries instead. This tests for the specific
2269                 // excess-retry case while also testing `PaymentFailed` generation.
2270
2271                 let chanmon_cfgs = create_chanmon_cfgs(3);
2272                 let node_cfgs = create_node_cfgs(3, &chanmon_cfgs);
2273                 let node_chanmgrs = create_node_chanmgrs(3, &node_cfgs, &[None, None, None]);
2274                 let nodes = create_network(3, &node_cfgs, &node_chanmgrs);
2275
2276                 let chan_1_scid = create_announced_chan_between_nodes_with_value(&nodes, 0, 1, 10_000_000, 0, channelmanager::provided_init_features(), channelmanager::provided_init_features()).0.contents.short_channel_id;
2277                 let chan_2_scid = create_announced_chan_between_nodes_with_value(&nodes, 1, 2, 10_000_000, 0, channelmanager::provided_init_features(), channelmanager::provided_init_features()).0.contents.short_channel_id;
2278
2279                 let mut route = Route {
2280                         paths: vec![
2281                                 vec![RouteHop {
2282                                         pubkey: nodes[1].node.get_our_node_id(),
2283                                         node_features: channelmanager::provided_node_features(),
2284                                         short_channel_id: chan_1_scid,
2285                                         channel_features: channelmanager::provided_channel_features(),
2286                                         fee_msat: 0,
2287                                         cltv_expiry_delta: 100,
2288                                 }, RouteHop {
2289                                         pubkey: nodes[2].node.get_our_node_id(),
2290                                         node_features: channelmanager::provided_node_features(),
2291                                         short_channel_id: chan_2_scid,
2292                                         channel_features: channelmanager::provided_channel_features(),
2293                                         fee_msat: 100_000_000,
2294                                         cltv_expiry_delta: 100,
2295                                 }],
2296                                 vec![RouteHop {
2297                                         pubkey: nodes[1].node.get_our_node_id(),
2298                                         node_features: channelmanager::provided_node_features(),
2299                                         short_channel_id: chan_1_scid,
2300                                         channel_features: channelmanager::provided_channel_features(),
2301                                         fee_msat: 0,
2302                                         cltv_expiry_delta: 100,
2303                                 }, RouteHop {
2304                                         pubkey: nodes[2].node.get_our_node_id(),
2305                                         node_features: channelmanager::provided_node_features(),
2306                                         short_channel_id: chan_2_scid,
2307                                         channel_features: channelmanager::provided_channel_features(),
2308                                         fee_msat: 100_000_000,
2309                                         cltv_expiry_delta: 100,
2310                                 }]
2311                         ],
2312                         payment_params: Some(PaymentParameters::from_node_id(nodes[2].node.get_our_node_id())),
2313                 };
2314                 let router = ManualRouter(RefCell::new(VecDeque::new()));
2315                 router.expect_find_route(Ok(route.clone()));
2316                 // On retry, we'll only be asked for one path
2317                 route.paths.remove(1);
2318                 router.expect_find_route(Ok(route.clone()));
2319
2320                 let expected_events: RefCell<VecDeque<&dyn Fn(&Event)>> = RefCell::new(VecDeque::new());
2321                 let event_handler = |event: &Event| {
2322                         let event_checker = expected_events.borrow_mut().pop_front().unwrap();
2323                         event_checker(event);
2324                 };
2325                 let invoice_payer = InvoicePayer::new(nodes[0].node, router, nodes[0].logger, event_handler, Retry::Attempts(1));
2326
2327                 assert!(invoice_payer.pay_invoice(&create_invoice_from_channelmanager_and_duration_since_epoch(
2328                         &nodes[1].node, nodes[1].keys_manager, Currency::Bitcoin, Some(100_010_000), "Invoice".to_string(),
2329                         duration_since_epoch(), 3600).unwrap())
2330                         .is_ok());
2331                 let htlc_updates = SendEvent::from_node(&nodes[0]);
2332                 check_added_monitors!(nodes[0], 1);
2333                 assert_eq!(htlc_updates.msgs.len(), 1);
2334
2335                 nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &htlc_updates.msgs[0]);
2336                 nodes[1].node.handle_commitment_signed(&nodes[0].node.get_our_node_id(), &htlc_updates.commitment_msg);
2337                 check_added_monitors!(nodes[1], 1);
2338                 let (bs_first_raa, bs_first_cs) = get_revoke_commit_msgs!(nodes[1], nodes[0].node.get_our_node_id());
2339
2340                 nodes[0].node.handle_revoke_and_ack(&nodes[1].node.get_our_node_id(), &bs_first_raa);
2341                 check_added_monitors!(nodes[0], 1);
2342                 let second_htlc_updates = SendEvent::from_node(&nodes[0]);
2343
2344                 nodes[0].node.handle_commitment_signed(&nodes[1].node.get_our_node_id(), &bs_first_cs);
2345                 check_added_monitors!(nodes[0], 1);
2346                 let as_first_raa = get_event_msg!(nodes[0], MessageSendEvent::SendRevokeAndACK, nodes[1].node.get_our_node_id());
2347
2348                 nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &second_htlc_updates.msgs[0]);
2349                 nodes[1].node.handle_commitment_signed(&nodes[0].node.get_our_node_id(), &second_htlc_updates.commitment_msg);
2350                 check_added_monitors!(nodes[1], 1);
2351                 let bs_second_raa = get_event_msg!(nodes[1], MessageSendEvent::SendRevokeAndACK, nodes[0].node.get_our_node_id());
2352
2353                 nodes[1].node.handle_revoke_and_ack(&nodes[0].node.get_our_node_id(), &as_first_raa);
2354                 check_added_monitors!(nodes[1], 1);
2355                 let bs_fail_update = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
2356
2357                 nodes[0].node.handle_revoke_and_ack(&nodes[1].node.get_our_node_id(), &bs_second_raa);
2358                 check_added_monitors!(nodes[0], 1);
2359
2360                 nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &bs_fail_update.update_fail_htlcs[0]);
2361                 nodes[0].node.handle_commitment_signed(&nodes[1].node.get_our_node_id(), &bs_fail_update.commitment_signed);
2362                 check_added_monitors!(nodes[0], 1);
2363                 let (as_second_raa, as_third_cs) = get_revoke_commit_msgs!(nodes[0], nodes[1].node.get_our_node_id());
2364
2365                 nodes[1].node.handle_revoke_and_ack(&nodes[0].node.get_our_node_id(), &as_second_raa);
2366                 check_added_monitors!(nodes[1], 1);
2367                 let bs_second_fail_update = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
2368
2369                 nodes[1].node.handle_commitment_signed(&nodes[0].node.get_our_node_id(), &as_third_cs);
2370                 check_added_monitors!(nodes[1], 1);
2371                 let bs_third_raa = get_event_msg!(nodes[1], MessageSendEvent::SendRevokeAndACK, nodes[0].node.get_our_node_id());
2372
2373                 nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &bs_second_fail_update.update_fail_htlcs[0]);
2374                 nodes[0].node.handle_commitment_signed(&nodes[1].node.get_our_node_id(), &bs_second_fail_update.commitment_signed);
2375                 check_added_monitors!(nodes[0], 1);
2376
2377                 nodes[0].node.handle_revoke_and_ack(&nodes[1].node.get_our_node_id(), &bs_third_raa);
2378                 check_added_monitors!(nodes[0], 1);
2379                 let (as_third_raa, as_fourth_cs) = get_revoke_commit_msgs!(nodes[0], nodes[1].node.get_our_node_id());
2380
2381                 nodes[1].node.handle_revoke_and_ack(&nodes[0].node.get_our_node_id(), &as_third_raa);
2382                 check_added_monitors!(nodes[1], 1);
2383                 nodes[1].node.handle_commitment_signed(&nodes[0].node.get_our_node_id(), &as_fourth_cs);
2384                 check_added_monitors!(nodes[1], 1);
2385                 let bs_fourth_raa = get_event_msg!(nodes[1], MessageSendEvent::SendRevokeAndACK, nodes[0].node.get_our_node_id());
2386
2387                 nodes[0].node.handle_revoke_and_ack(&nodes[1].node.get_our_node_id(), &bs_fourth_raa);
2388                 check_added_monitors!(nodes[0], 1);
2389
2390                 // At this point A has sent two HTLCs which both failed due to lack of fee. It now has two
2391                 // pending `PaymentPathFailed` events, one with `all_paths_failed` unset, and the second
2392                 // with it set. The first event will use up the only retry we are allowed, with the second
2393                 // `PaymentPathFailed` being passed up to the user (us, in this case). Previously, we'd
2394                 // treated this as "HTLC complete" and dropped the retry counter, causing us to retry again
2395                 // if the final HTLC failed.
2396                 expected_events.borrow_mut().push_back(&|ev: &Event| {
2397                         if let Event::PaymentPathFailed { payment_failed_permanently, all_paths_failed, .. } = ev {
2398                                 assert!(!payment_failed_permanently);
2399                                 assert!(all_paths_failed);
2400                         } else { panic!("Unexpected event"); }
2401                 });
2402                 nodes[0].node.process_pending_events(&invoice_payer);
2403                 assert!(expected_events.borrow().is_empty());
2404
2405                 let retry_htlc_updates = SendEvent::from_node(&nodes[0]);
2406                 check_added_monitors!(nodes[0], 1);
2407
2408                 nodes[1].node.handle_update_add_htlc(&nodes[0].node.get_our_node_id(), &retry_htlc_updates.msgs[0]);
2409                 commitment_signed_dance!(nodes[1], nodes[0], &retry_htlc_updates.commitment_msg, false, true);
2410                 let bs_fail_update = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
2411                 nodes[0].node.handle_update_fail_htlc(&nodes[1].node.get_our_node_id(), &bs_fail_update.update_fail_htlcs[0]);
2412                 commitment_signed_dance!(nodes[0], nodes[1], &bs_fail_update.commitment_signed, false, true);
2413
2414                 expected_events.borrow_mut().push_back(&|ev: &Event| {
2415                         if let Event::PaymentPathFailed { payment_failed_permanently, all_paths_failed, .. } = ev {
2416                                 assert!(!payment_failed_permanently);
2417                                 assert!(all_paths_failed);
2418                         } else { panic!("Unexpected event"); }
2419                 });
2420                 expected_events.borrow_mut().push_back(&|ev: &Event| {
2421                         if let Event::PaymentFailed { .. } = ev {
2422                         } else { panic!("Unexpected event"); }
2423                 });
2424                 nodes[0].node.process_pending_events(&invoice_payer);
2425                 assert!(expected_events.borrow().is_empty());
2426         }
2427 }