_ Git - rust-lightning/blob - lightning/src/ln/outbound_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 //! Utilities to send payments and manage outbound payment information.
  11
  12 use bitcoin::hashes::Hash;
  13 use bitcoin::hashes::sha256::Hash as Sha256;
  14 use bitcoin::secp256k1::{self, Secp256k1, SecretKey};
  15
  16 use crate::chain::keysinterface::{EntropySource, NodeSigner, Recipient};
  17 use crate::ln::{PaymentHash, PaymentPreimage, PaymentSecret};
  18 use crate::ln::channelmanager::{ChannelDetails, HTLCSource, IDEMPOTENCY_TIMEOUT_TICKS, MIN_HTLC_RELAY_HOLDING_CELL_MILLIS, PaymentId};
  19 use crate::ln::msgs::DecodeError;
  20 use crate::ln::onion_utils::HTLCFailReason;
  21 use crate::routing::router::{InFlightHtlcs, PaymentParameters, Route, RouteHop, RouteParameters, RoutePath, Router};
  22 use crate::util::errors::APIError;
  23 use crate::util::events;
  24 use crate::util::logger::Logger;
  25 use crate::util::time::Time;
  26 #[cfg(all(not(feature = "no-std"), test))]
  27 use crate::util::time::tests::SinceEpoch;
  28
  29 use core::cmp;
  30 use core::fmt::{self, Display, Formatter};
  31 use core::ops::Deref;
  32 use core::time::Duration;
  33
  34 use crate::prelude::*;
  35 use crate::sync::Mutex;
  36
  37 /// Stores the session_priv for each part of a payment that is still pending. For versions 0.0.102
  38 /// and later, also stores information for retrying the payment.
  39 pub(crate) enum PendingOutboundPayment {
  40         Legacy {
  41                 session_privs: HashSet<[u8; 32]>,
  42         },
  43         Retryable {
  44                 retry_strategy: Retry,
  45                 attempts: PaymentAttempts,
  46                 route_params: Option<RouteParameters>,
  47                 session_privs: HashSet<[u8; 32]>,
  48                 payment_hash: PaymentHash,
  49                 payment_secret: Option<PaymentSecret>,
  50                 pending_amt_msat: u64,
  51                 /// Used to track the fee paid. Only present if the payment was serialized on 0.0.103+.
  52                 pending_fee_msat: Option<u64>,
  53                 /// The total payment amount across all paths, used to verify that a retry is not overpaying.
  54                 total_msat: u64,
  55                 /// Our best known block height at the time this payment was initiated.
  56                 starting_block_height: u32,
  57         },
  58         /// When a pending payment is fulfilled, we continue tracking it until all pending HTLCs have
  59         /// been resolved. This ensures we don't look up pending payments in ChannelMonitors on restart
  60         /// and add a pending payment that was already fulfilled.
  61         Fulfilled {
  62                 session_privs: HashSet<[u8; 32]>,
  63                 payment_hash: Option<PaymentHash>,
  64                 timer_ticks_without_htlcs: u8,
  65         },
  66         /// When a payer gives up trying to retry a payment, they inform us, letting us generate a
  67         /// `PaymentFailed` event when all HTLCs have irrevocably failed. This avoids a number of race
  68         /// conditions in MPP-aware payment retriers (1), where the possibility of multiple
  69         /// `PaymentPathFailed` events with `all_paths_failed` can be pending at once, confusing a
  70         /// downstream event handler as to when a payment has actually failed.
  71         ///
  72         /// (1) <https://github.com/lightningdevkit/rust-lightning/issues/1164>
  73         Abandoned {
  74                 session_privs: HashSet<[u8; 32]>,
  75                 payment_hash: PaymentHash,
  76         },
  77 }
  78
  79 impl PendingOutboundPayment {
  80         fn increment_attempts(&mut self) {
  81                 if let PendingOutboundPayment::Retryable { attempts, .. } = self {
  82                         attempts.count += 1;
  83                 }
  84         }
  85         fn is_retryable_now(&self) -> bool {
  86                 if let PendingOutboundPayment::Retryable { retry_strategy, attempts, .. } = self {
  87                         return retry_strategy.is_retryable_now(&attempts)
  88                 }
  89                 false
  90         }
  91         pub fn insert_previously_failed_scid(&mut self, scid: u64) {
  92                 if let PendingOutboundPayment::Retryable { route_params: Some(params), .. } = self {
  93                         params.payment_params.previously_failed_channels.push(scid);
  94                 }
  95         }
  96         pub(super) fn is_fulfilled(&self) -> bool {
  97                 match self {
  98                         PendingOutboundPayment::Fulfilled { .. } => true,
  99                         _ => false,
 100                 }
 101         }
 102         pub(super) fn abandoned(&self) -> bool {
 103                 match self {
 104                         PendingOutboundPayment::Abandoned { .. } => true,
 105                         _ => false,
 106                 }
 107         }
 108         fn get_pending_fee_msat(&self) -> Option<u64> {
 109                 match self {
 110                         PendingOutboundPayment::Retryable { pending_fee_msat, .. } => pending_fee_msat.clone(),
 111                         _ => None,
 112                 }
 113         }
 114
 115         fn payment_hash(&self) -> Option<PaymentHash> {
 116                 match self {
 117                         PendingOutboundPayment::Legacy { .. } => None,
 118                         PendingOutboundPayment::Retryable { payment_hash, .. } => Some(*payment_hash),
 119                         PendingOutboundPayment::Fulfilled { payment_hash, .. } => *payment_hash,
 120                         PendingOutboundPayment::Abandoned { payment_hash, .. } => Some(*payment_hash),
 121                 }
 122         }
 123
 124         fn mark_fulfilled(&mut self) {
 125                 let mut session_privs = HashSet::new();
 126                 core::mem::swap(&mut session_privs, match self {
 127                         PendingOutboundPayment::Legacy { session_privs } |
 128                                 PendingOutboundPayment::Retryable { session_privs, .. } |
 129                                 PendingOutboundPayment::Fulfilled { session_privs, .. } |
 130                                 PendingOutboundPayment::Abandoned { session_privs, .. }
 131                         => session_privs,
 132                 });
 133                 let payment_hash = self.payment_hash();
 134                 *self = PendingOutboundPayment::Fulfilled { session_privs, payment_hash, timer_ticks_without_htlcs: 0 };
 135         }
 136
 137         fn mark_abandoned(&mut self) -> Result<(), ()> {
 138                 let mut session_privs = HashSet::new();
 139                 let our_payment_hash;
 140                 core::mem::swap(&mut session_privs, match self {
 141                         PendingOutboundPayment::Legacy { .. } |
 142                                 PendingOutboundPayment::Fulfilled { .. } =>
 143                                 return Err(()),
 144                                 PendingOutboundPayment::Retryable { session_privs, payment_hash, .. } |
 145                                         PendingOutboundPayment::Abandoned { session_privs, payment_hash, .. } => {
 146                                                 our_payment_hash = *payment_hash;
 147                                                 session_privs
 148                                         },
 149                 });
 150                 *self = PendingOutboundPayment::Abandoned { session_privs, payment_hash: our_payment_hash };
 151                 Ok(())
 152         }
 153
 154         /// panics if path is None and !self.is_fulfilled
 155         fn remove(&mut self, session_priv: &[u8; 32], path: Option<&Vec<RouteHop>>) -> bool {
 156                 let remove_res = match self {
 157                         PendingOutboundPayment::Legacy { session_privs } |
 158                                 PendingOutboundPayment::Retryable { session_privs, .. } |
 159                                 PendingOutboundPayment::Fulfilled { session_privs, .. } |
 160                                 PendingOutboundPayment::Abandoned { session_privs, .. } => {
 161                                         session_privs.remove(session_priv)
 162                                 }
 163                 };
 164                 if remove_res {
 165                         if let PendingOutboundPayment::Retryable { ref mut pending_amt_msat, ref mut pending_fee_msat, .. } = self {
 166                                 let path = path.expect("Fulfilling a payment should always come with a path");
 167                                 let path_last_hop = path.last().expect("Outbound payments must have had a valid path");
 168                                 *pending_amt_msat -= path_last_hop.fee_msat;
 169                                 if let Some(fee_msat) = pending_fee_msat.as_mut() {
 170                                         *fee_msat -= path.get_path_fees();
 171                                 }
 172                         }
 173                 }
 174                 remove_res
 175         }
 176
 177         pub(super) fn insert(&mut self, session_priv: [u8; 32], path: &Vec<RouteHop>) -> bool {
 178                 let insert_res = match self {
 179                         PendingOutboundPayment::Legacy { session_privs } |
 180                                 PendingOutboundPayment::Retryable { session_privs, .. } => {
 181                                         session_privs.insert(session_priv)
 182                                 }
 183                         PendingOutboundPayment::Fulfilled { .. } => false,
 184                         PendingOutboundPayment::Abandoned { .. } => false,
 185                 };
 186                 if insert_res {
 187                         if let PendingOutboundPayment::Retryable { ref mut pending_amt_msat, ref mut pending_fee_msat, .. } = self {
 188                                 let path_last_hop = path.last().expect("Outbound payments must have had a valid path");
 189                                 *pending_amt_msat += path_last_hop.fee_msat;
 190                                 if let Some(fee_msat) = pending_fee_msat.as_mut() {
 191                                         *fee_msat += path.get_path_fees();
 192                                 }
 193                         }
 194                 }
 195                 insert_res
 196         }
 197
 198         pub(super) fn remaining_parts(&self) -> usize {
 199                 match self {
 200                         PendingOutboundPayment::Legacy { session_privs } |
 201                                 PendingOutboundPayment::Retryable { session_privs, .. } |
 202                                 PendingOutboundPayment::Fulfilled { session_privs, .. } |
 203                                 PendingOutboundPayment::Abandoned { session_privs, .. } => {
 204                                         session_privs.len()
 205                                 }
 206                 }
 207         }
 208 }
 209
 210 /// Strategies available to retry payment path failures.
 211 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
 212 pub enum Retry {
 213         /// Max number of attempts to retry payment.
 214         ///
 215         /// Note that this is the number of *path* failures, not full payment retries. For multi-path
 216         /// payments, if this is less than the total number of paths, we will never even retry all of the
 217         /// payment's paths.
 218         Attempts(usize),
 219         #[cfg(not(feature = "no-std"))]
 220         /// Time elapsed before abandoning retries for a payment.
 221         Timeout(core::time::Duration),
 222 }
 223
 224 impl Retry {
 225         pub(crate) fn is_retryable_now(&self, attempts: &PaymentAttempts) -> bool {
 226                 match (self, attempts) {
 227                         (Retry::Attempts(max_retry_count), PaymentAttempts { count, .. }) => {
 228                                 max_retry_count > count
 229                         },
 230                         #[cfg(all(not(feature = "no-std"), not(test)))]
 231                         (Retry::Timeout(max_duration), PaymentAttempts { first_attempted_at, .. }) =>
 232                                 *max_duration >= std::time::Instant::now().duration_since(*first_attempted_at),
 233                         #[cfg(all(not(feature = "no-std"), test))]
 234                         (Retry::Timeout(max_duration), PaymentAttempts { first_attempted_at, .. }) =>
 235                                 *max_duration >= SinceEpoch::now().duration_since(*first_attempted_at),
 236                 }
 237         }
 238 }
 239
 240 #[cfg(feature = "std")]
 241 pub(super) fn has_expired(route_params: &RouteParameters) -> bool {
 242         if let Some(expiry_time) = route_params.payment_params.expiry_time {
 243                 if let Ok(elapsed) = std::time::SystemTime::UNIX_EPOCH.elapsed() {
 244                         return elapsed > core::time::Duration::from_secs(expiry_time)
 245                 }
 246         }
 247         false
 248 }
 249
 250 pub(crate) type PaymentAttempts = PaymentAttemptsUsingTime<ConfiguredTime>;
 251
 252 /// Storing minimal payment attempts information required for determining if a outbound payment can
 253 /// be retried.
 254 pub(crate) struct PaymentAttemptsUsingTime<T: Time> {
 255         /// This count will be incremented only after the result of the attempt is known. When it's 0,
 256         /// it means the result of the first attempt is not known yet.
 257         pub(crate) count: usize,
 258         /// This field is only used when retry is `Retry::Timeout` which is only build with feature std
 259         first_attempted_at: T
 260 }
 261
 262 #[cfg(not(any(feature = "no-std", test)))]
 263 type ConfiguredTime = std::time::Instant;
 264 #[cfg(feature = "no-std")]
 265 type ConfiguredTime = crate::util::time::Eternity;
 266 #[cfg(all(not(feature = "no-std"), test))]
 267 type ConfiguredTime = SinceEpoch;
 268
 269 impl<T: Time> PaymentAttemptsUsingTime<T> {
 270         pub(crate) fn new() -> Self {
 271                 PaymentAttemptsUsingTime {
 272                         count: 0,
 273                         first_attempted_at: T::now()
 274                 }
 275         }
 276 }
 277
 278 impl<T: Time> Display for PaymentAttemptsUsingTime<T> {
 279         fn fmt(&self, f: &mut Formatter) -> Result<(), fmt::Error> {
 280                 #[cfg(feature = "no-std")]
 281                 return write!(f, "attempts: {}", self.count);
 282                 #[cfg(not(feature = "no-std"))]
 283                 return write!(
 284                         f,
 285                         "attempts: {}, duration: {}s",
 286                         self.count,
 287                         T::now().duration_since(self.first_attempted_at).as_secs()
 288                 );
 289         }
 290 }
 291
 292 /// If a payment fails to send, it can be in one of several states. This enum is returned as the
 293 /// Err() type describing which state the payment is in, see the description of individual enum
 294 /// states for more.
 295 #[derive(Clone, Debug)]
 296 pub enum PaymentSendFailure {
 297         /// A parameter which was passed to send_payment was invalid, preventing us from attempting to
 298         /// send the payment at all.
 299         ///
 300         /// You can freely resend the payment in full (with the parameter error fixed).
 301         ///
 302         /// Because the payment failed outright, no payment tracking is done, you do not need to call
 303         /// [`ChannelManager::abandon_payment`] and [`ChannelManager::retry_payment`] will *not* work
 304         /// for this payment.
 305         ///
 306         /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
 307         /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
 308         ParameterError(APIError),
 309         /// A parameter in a single path which was passed to send_payment was invalid, preventing us
 310         /// from attempting to send the payment at all.
 311         ///
 312         /// You can freely resend the payment in full (with the parameter error fixed).
 313         ///
 314         /// The results here are ordered the same as the paths in the route object which was passed to
 315         /// send_payment.
 316         ///
 317         /// Because the payment failed outright, no payment tracking is done, you do not need to call
 318         /// [`ChannelManager::abandon_payment`] and [`ChannelManager::retry_payment`] will *not* work
 319         /// for this payment.
 320         ///
 321         /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
 322         /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
 323         PathParameterError(Vec<Result<(), APIError>>),
 324         /// All paths which were attempted failed to send, with no channel state change taking place.
 325         /// You can freely resend the payment in full (though you probably want to do so over different
 326         /// paths than the ones selected).
 327         ///
 328         /// Because the payment failed outright, no payment tracking is done, you do not need to call
 329         /// [`ChannelManager::abandon_payment`] and [`ChannelManager::retry_payment`] will *not* work
 330         /// for this payment.
 331         ///
 332         /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
 333         /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
 334         AllFailedResendSafe(Vec<APIError>),
 335         /// Indicates that a payment for the provided [`PaymentId`] is already in-flight and has not
 336         /// yet completed (i.e. generated an [`Event::PaymentSent`]) or been abandoned (via
 337         /// [`ChannelManager::abandon_payment`]).
 338         ///
 339         /// [`PaymentId`]: crate::ln::channelmanager::PaymentId
 340         /// [`Event::PaymentSent`]: crate::util::events::Event::PaymentSent
 341         /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
 342         DuplicatePayment,
 343         /// Some paths which were attempted failed to send, though possibly not all. At least some
 344         /// paths have irrevocably committed to the HTLC and retrying the payment in full would result
 345         /// in over-/re-payment.
 346         ///
 347         /// The results here are ordered the same as the paths in the route object which was passed to
 348         /// send_payment, and any `Err`s which are not [`APIError::MonitorUpdateInProgress`] can be
 349         /// safely retried via [`ChannelManager::retry_payment`].
 350         ///
 351         /// Any entries which contain `Err(APIError::MonitorUpdateInprogress)` or `Ok(())` MUST NOT be
 352         /// retried as they will result in over-/re-payment. These HTLCs all either successfully sent
 353         /// (in the case of `Ok(())`) or will send once a [`MonitorEvent::Completed`] is provided for
 354         /// the next-hop channel with the latest update_id.
 355         ///
 356         /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
 357         /// [`MonitorEvent::Completed`]: crate::chain::channelmonitor::MonitorEvent::Completed
 358         PartialFailure {
 359                 /// The errors themselves, in the same order as the route hops.
 360                 results: Vec<Result<(), APIError>>,
 361                 /// If some paths failed without irrevocably committing to the new HTLC(s), this will
 362                 /// contain a [`RouteParameters`] object which can be used to calculate a new route that
 363                 /// will pay all remaining unpaid balance.
 364                 failed_paths_retry: Option<RouteParameters>,
 365                 /// The payment id for the payment, which is now at least partially pending.
 366                 payment_id: PaymentId,
 367         },
 368 }
 369
 370 pub(super) struct OutboundPayments {
 371         pub(super) pending_outbound_payments: Mutex<HashMap<PaymentId, PendingOutboundPayment>>,
 372 }
 373
 374 impl OutboundPayments {
 375         pub(super) fn new() -> Self {
 376                 Self {
 377                         pending_outbound_payments: Mutex::new(HashMap::new())
 378                 }
 379         }
 380
 381         pub(super) fn send_payment<R: Deref, ES: Deref, NS: Deref, F>(
 382                 &self, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>, payment_id: PaymentId,
 383                 retry_strategy: Retry, route_params: RouteParameters, router: &R,
 384                 first_hops: Vec<ChannelDetails>, inflight_htlcs: InFlightHtlcs, entropy_source: &ES,
 385                 node_signer: &NS, best_block_height: u32, send_payment_along_path: F
 386         ) -> Result<(), PaymentSendFailure>
 387         where
 388                 R::Target: Router,
 389                 ES::Target: EntropySource,
 390                 NS::Target: NodeSigner,
 391                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 392                          u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>,
 393         {
 394                 self.pay_internal(payment_id, Some((payment_hash, payment_secret, retry_strategy)),
 395                         route_params, router, first_hops, inflight_htlcs, entropy_source, node_signer,
 396                         best_block_height, &send_payment_along_path)
 397                         .map_err(|e| { self.remove_outbound_if_all_failed(payment_id, &e); e })
 398         }
 399
 400         pub(super) fn send_payment_with_route<ES: Deref, NS: Deref, F>(
 401                 &self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>,
 402                 payment_id: PaymentId, entropy_source: &ES, node_signer: &NS, best_block_height: u32,
 403                 send_payment_along_path: F
 404         ) -> Result<(), PaymentSendFailure>
 405         where
 406                 ES::Target: EntropySource,
 407                 NS::Target: NodeSigner,
 408                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 409                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 410         {
 411                 let onion_session_privs = self.add_new_pending_payment(payment_hash, *payment_secret, payment_id, route, Retry::Attempts(0), None, entropy_source, best_block_height)?;
 412                 self.send_payment_internal(route, payment_hash, payment_secret, None, payment_id, None,
 413                         onion_session_privs, node_signer, best_block_height, &send_payment_along_path)
 414                         .map_err(|e| { self.remove_outbound_if_all_failed(payment_id, &e); e })
 415         }
 416
 417         pub(super) fn send_spontaneous_payment<ES: Deref, NS: Deref, F>(
 418                 &self, route: &Route, payment_preimage: Option<PaymentPreimage>, payment_id: PaymentId,
 419                 entropy_source: &ES, node_signer: &NS, best_block_height: u32, send_payment_along_path: F
 420         ) -> Result<PaymentHash, PaymentSendFailure>
 421         where
 422                 ES::Target: EntropySource,
 423                 NS::Target: NodeSigner,
 424                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 425                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 426         {
 427                 let preimage = match payment_preimage {
 428                         Some(p) => p,
 429                         None => PaymentPreimage(entropy_source.get_secure_random_bytes()),
 430                 };
 431                 let payment_hash = PaymentHash(Sha256::hash(&preimage.0).into_inner());
 432                 let onion_session_privs = self.add_new_pending_payment(payment_hash, None, payment_id, &route, Retry::Attempts(0), None, entropy_source, best_block_height)?;
 433
 434                 match self.send_payment_internal(route, payment_hash, &None, Some(preimage), payment_id, None, onion_session_privs, node_signer, best_block_height, &send_payment_along_path) {
 435                         Ok(()) => Ok(payment_hash),
 436                         Err(e) => {
 437                                 self.remove_outbound_if_all_failed(payment_id, &e);
 438                                 Err(e)
 439                         }
 440                 }
 441         }
 442
 443         pub(super) fn check_retry_payments<R: Deref, ES: Deref, NS: Deref, SP, IH, FH, L: Deref>(
 444                 &self, router: &R, first_hops: FH, inflight_htlcs: IH, entropy_source: &ES, node_signer: &NS,
 445                 best_block_height: u32, logger: &L, send_payment_along_path: SP,
 446         )
 447         where
 448                 R::Target: Router,
 449                 ES::Target: EntropySource,
 450                 NS::Target: NodeSigner,
 451                 SP: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 452                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>,
 453                 IH: Fn() -> InFlightHtlcs,
 454                 FH: Fn() -> Vec<ChannelDetails>,
 455                 L::Target: Logger,
 456         {
 457                 loop {
 458                         let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 459                         let mut retry_id_route_params = None;
 460                         for (pmt_id, pmt) in outbounds.iter_mut() {
 461                                 if pmt.is_retryable_now() {
 462                                         if let PendingOutboundPayment::Retryable { pending_amt_msat, total_msat, route_params: Some(params), .. } = pmt {
 463                                                 if pending_amt_msat < total_msat {
 464                                                         retry_id_route_params = Some((*pmt_id, params.clone()));
 465                                                         pmt.increment_attempts();
 466                                                         break
 467                                                 }
 468                                         }
 469                                 }
 470                         }
 471                         if let Some((payment_id, route_params)) = retry_id_route_params {
 472                                 core::mem::drop(outbounds);
 473                                 if let Err(e) = self.pay_internal(payment_id, None, route_params, router, first_hops(), inflight_htlcs(), entropy_source, node_signer, best_block_height, &send_payment_along_path) {
 474                                         log_trace!(logger, "Errored retrying payment: {:?}", e);
 475                                 }
 476                         } else { break }
 477                 }
 478         }
 479
 480         fn pay_internal<R: Deref, NS: Deref, ES: Deref, F>(
 481                 &self, payment_id: PaymentId,
 482                 initial_send_info: Option<(PaymentHash, &Option<PaymentSecret>, Retry)>,
 483                 route_params: RouteParameters, router: &R, first_hops: Vec<ChannelDetails>,
 484                 inflight_htlcs: InFlightHtlcs, entropy_source: &ES, node_signer: &NS, best_block_height: u32,
 485                 send_payment_along_path: &F
 486         ) -> Result<(), PaymentSendFailure>
 487         where
 488                 R::Target: Router,
 489                 ES::Target: EntropySource,
 490                 NS::Target: NodeSigner,
 491                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 492                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 493         {
 494                 #[cfg(feature = "std")] {
 495                         if has_expired(&route_params) {
 496                                 return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 497                                         err: format!("Invoice expired for payment id {}", log_bytes!(payment_id.0)),
 498                                 }))
 499                         }
 500                 }
 501
 502                 let route = router.find_route(
 503                         &node_signer.get_node_id(Recipient::Node).unwrap(), &route_params,
 504                         Some(&first_hops.iter().collect::<Vec<_>>()), &inflight_htlcs
 505                 ).map_err(|e| PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 506                         err: format!("Failed to find a route for payment {}: {:?}", log_bytes!(payment_id.0), e), // TODO: add APIError::RouteNotFound
 507                 }))?;
 508
 509                 let res = if let Some((payment_hash, payment_secret, retry_strategy)) = initial_send_info {
 510                         let onion_session_privs = self.add_new_pending_payment(payment_hash, *payment_secret, payment_id, &route, retry_strategy, Some(route_params.clone()), entropy_source, best_block_height)?;
 511                         self.send_payment_internal(&route, payment_hash, payment_secret, None, payment_id, None, onion_session_privs, node_signer, best_block_height, send_payment_along_path)
 512                 } else {
 513                         self.retry_payment_with_route(&route, payment_id, entropy_source, node_signer, best_block_height, send_payment_along_path)
 514                 };
 515                 match res {
 516                         Err(PaymentSendFailure::AllFailedResendSafe(_)) => {
 517                                 let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 518                                 if let Some(payment) = outbounds.get_mut(&payment_id) {
 519                                         let retryable = payment.is_retryable_now();
 520                                         if retryable {
 521                                                 payment.increment_attempts();
 522                                         } else { return res }
 523                                 } else { return res }
 524                                 core::mem::drop(outbounds);
 525                                 self.pay_internal(payment_id, None, route_params, router, first_hops, inflight_htlcs, entropy_source, node_signer, best_block_height, send_payment_along_path)
 526                         },
 527                         Err(PaymentSendFailure::PartialFailure { failed_paths_retry: Some(retry), results, .. }) => {
 528                                 let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 529                                 if let Some(payment) = outbounds.get_mut(&payment_id) {
 530                                         let retryable = payment.is_retryable_now();
 531                                         if retryable {
 532                                                 payment.increment_attempts();
 533                                         } else { return Err(PaymentSendFailure::PartialFailure { failed_paths_retry: Some(retry), results, payment_id }) }
 534                                 } else { return Err(PaymentSendFailure::PartialFailure { failed_paths_retry: Some(retry), results, payment_id }) }
 535                                 core::mem::drop(outbounds);
 536
 537                                 // Some paths were sent, even if we failed to send the full MPP value our recipient may
 538                                 // misbehave and claim the funds, at which point we have to consider the payment sent, so
 539                                 // return `Ok()` here, ignoring any retry errors.
 540                                 let _ = self.pay_internal(payment_id, None, retry, router, first_hops, inflight_htlcs, entropy_source, node_signer, best_block_height, send_payment_along_path);
 541                                 Ok(())
 542                         },
 543                         Err(PaymentSendFailure::PartialFailure { failed_paths_retry: None, .. }) => {
 544                                 // This may happen if we send a payment and some paths fail, but only due to a temporary
 545                                 // monitor failure or the like, implying they're really in-flight, but we haven't sent the
 546                                 // initial HTLC-Add messages yet.
 547                                 Ok(())
 548                         },
 549                         res => res,
 550                 }
 551         }
 552
 553         pub(super) fn retry_payment_with_route<ES: Deref, NS: Deref, F>(
 554                 &self, route: &Route, payment_id: PaymentId, entropy_source: &ES, node_signer: &NS, best_block_height: u32,
 555                 send_payment_along_path: F
 556         ) -> Result<(), PaymentSendFailure>
 557         where
 558                 ES::Target: EntropySource,
 559                 NS::Target: NodeSigner,
 560                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 561                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 562         {
 563                 const RETRY_OVERFLOW_PERCENTAGE: u64 = 10;
 564                 for path in route.paths.iter() {
 565                         if path.len() == 0 {
 566                                 return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 567                                         err: "length-0 path in route".to_string()
 568                                 }))
 569                         }
 570                 }
 571
 572                 let mut onion_session_privs = Vec::with_capacity(route.paths.len());
 573                 for _ in 0..route.paths.len() {
 574                         onion_session_privs.push(entropy_source.get_secure_random_bytes());
 575                 }
 576
 577                 let (total_msat, payment_hash, payment_secret) = {
 578                         let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 579                         match outbounds.get_mut(&payment_id) {
 580                                 Some(payment) => {
 581                                         let res = match payment {
 582                                                 PendingOutboundPayment::Retryable {
 583                                                         total_msat, payment_hash, payment_secret, pending_amt_msat, ..
 584                                                 } => {
 585                                                         let retry_amt_msat: u64 = route.paths.iter().map(|path| path.last().unwrap().fee_msat).sum();
 586                                                         if retry_amt_msat + *pending_amt_msat > *total_msat * (100 + RETRY_OVERFLOW_PERCENTAGE) / 100 {
 587                                                                 return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 588                                                                         err: format!("retry_amt_msat of {} will put pending_amt_msat (currently: {}) more than 10% over total_payment_amt_msat of {}", retry_amt_msat, pending_amt_msat, total_msat).to_string()
 589                                                                 }))
 590                                                         }
 591                                                         (*total_msat, *payment_hash, *payment_secret)
 592                                                 },
 593                                                 PendingOutboundPayment::Legacy { .. } => {
 594                                                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 595                                                                 err: "Unable to retry payments that were initially sent on LDK versions prior to 0.0.102".to_string()
 596                                                         }))
 597                                                 },
 598                                                 PendingOutboundPayment::Fulfilled { .. } => {
 599                                                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 600                                                                 err: "Payment already completed".to_owned()
 601                                                         }));
 602                                                 },
 603                                                 PendingOutboundPayment::Abandoned { .. } => {
 604                                                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 605                                                                 err: "Payment already abandoned (with some HTLCs still pending)".to_owned()
 606                                                         }));
 607                                                 },
 608                                         };
 609                                         for (path, session_priv_bytes) in route.paths.iter().zip(onion_session_privs.iter()) {
 610                                                 assert!(payment.insert(*session_priv_bytes, path));
 611                                         }
 612                                         res
 613                                 },
 614                                 None =>
 615                                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 616                                                 err: format!("Payment with ID {} not found", log_bytes!(payment_id.0)),
 617                                         })),
 618                         }
 619                 };
 620                 self.send_payment_internal(route, payment_hash, &payment_secret, None, payment_id, Some(total_msat), onion_session_privs, node_signer, best_block_height, &send_payment_along_path)
 621         }
 622
 623         pub(super) fn send_probe<ES: Deref, NS: Deref, F>(
 624                 &self, hops: Vec<RouteHop>, probing_cookie_secret: [u8; 32], entropy_source: &ES,
 625                 node_signer: &NS, best_block_height: u32, send_payment_along_path: F
 626         ) -> Result<(PaymentHash, PaymentId), PaymentSendFailure>
 627         where
 628                 ES::Target: EntropySource,
 629                 NS::Target: NodeSigner,
 630                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 631                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 632         {
 633                 let payment_id = PaymentId(entropy_source.get_secure_random_bytes());
 634
 635                 let payment_hash = probing_cookie_from_id(&payment_id, probing_cookie_secret);
 636
 637                 if hops.len() < 2 {
 638                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 639                                 err: "No need probing a path with less than two hops".to_string()
 640                         }))
 641                 }
 642
 643                 let route = Route { paths: vec![hops], payment_params: None };
 644                 let onion_session_privs = self.add_new_pending_payment(payment_hash, None, payment_id, &route, Retry::Attempts(0), None, entropy_source, best_block_height)?;
 645
 646                 match self.send_payment_internal(&route, payment_hash, &None, None, payment_id, None, onion_session_privs, node_signer, best_block_height, &send_payment_along_path) {
 647                         Ok(()) => Ok((payment_hash, payment_id)),
 648                         Err(e) => {
 649                                 self.remove_outbound_if_all_failed(payment_id, &e);
 650                                 Err(e)
 651                         }
 652                 }
 653         }
 654
 655         #[cfg(test)]
 656         pub(super) fn test_add_new_pending_payment<ES: Deref>(
 657                 &self, payment_hash: PaymentHash, payment_secret: Option<PaymentSecret>, payment_id: PaymentId,
 658                 route: &Route, retry_strategy: Retry, entropy_source: &ES, best_block_height: u32
 659         ) -> Result<Vec<[u8; 32]>, PaymentSendFailure> where ES::Target: EntropySource {
 660                 self.add_new_pending_payment(payment_hash, payment_secret, payment_id, route, retry_strategy, None, entropy_source, best_block_height)
 661         }
 662
 663         pub(super) fn add_new_pending_payment<ES: Deref>(
 664                 &self, payment_hash: PaymentHash, payment_secret: Option<PaymentSecret>, payment_id: PaymentId,
 665                 route: &Route, retry_strategy: Retry, route_params: Option<RouteParameters>,
 666                 entropy_source: &ES, best_block_height: u32
 667         ) -> Result<Vec<[u8; 32]>, PaymentSendFailure> where ES::Target: EntropySource {
 668                 let mut onion_session_privs = Vec::with_capacity(route.paths.len());
 669                 for _ in 0..route.paths.len() {
 670                         onion_session_privs.push(entropy_source.get_secure_random_bytes());
 671                 }
 672
 673                 let mut pending_outbounds = self.pending_outbound_payments.lock().unwrap();
 674                 match pending_outbounds.entry(payment_id) {
 675                         hash_map::Entry::Occupied(_) => Err(PaymentSendFailure::DuplicatePayment),
 676                         hash_map::Entry::Vacant(entry) => {
 677                                 let payment = entry.insert(PendingOutboundPayment::Retryable {
 678                                         retry_strategy,
 679                                         attempts: PaymentAttempts::new(),
 680                                         route_params,
 681                                         session_privs: HashSet::new(),
 682                                         pending_amt_msat: 0,
 683                                         pending_fee_msat: Some(0),
 684                                         payment_hash,
 685                                         payment_secret,
 686                                         starting_block_height: best_block_height,
 687                                         total_msat: route.get_total_amount(),
 688                                 });
 689
 690                                 for (path, session_priv_bytes) in route.paths.iter().zip(onion_session_privs.iter()) {
 691                                         assert!(payment.insert(*session_priv_bytes, path));
 692                                 }
 693
 694                                 Ok(onion_session_privs)
 695                         },
 696                 }
 697         }
 698
 699         fn send_payment_internal<NS: Deref, F>(
 700                 &self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>,
 701                 keysend_preimage: Option<PaymentPreimage>, payment_id: PaymentId, recv_value_msat: Option<u64>,
 702                 onion_session_privs: Vec<[u8; 32]>, node_signer: &NS, best_block_height: u32,
 703                 send_payment_along_path: &F
 704         ) -> Result<(), PaymentSendFailure>
 705         where
 706                 NS::Target: NodeSigner,
 707                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 708                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 709         {
 710                 if route.paths.len() < 1 {
 711                         return Err(PaymentSendFailure::ParameterError(APIError::InvalidRoute{err: "There must be at least one path to send over"}));
 712                 }
 713                 if payment_secret.is_none() && route.paths.len() > 1 {
 714                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError{err: "Payment secret is required for multi-path payments".to_string()}));
 715                 }
 716                 let mut total_value = 0;
 717                 let our_node_id = node_signer.get_node_id(Recipient::Node).unwrap(); // TODO no unwrap
 718                 let mut path_errs = Vec::with_capacity(route.paths.len());
 719                 'path_check: for path in route.paths.iter() {
 720                         if path.len() < 1 || path.len() > 20 {
 721                                 path_errs.push(Err(APIError::InvalidRoute{err: "Path didn't go anywhere/had bogus size"}));
 722                                 continue 'path_check;
 723                         }
 724                         for (idx, hop) in path.iter().enumerate() {
 725                                 if idx != path.len() - 1 && hop.pubkey == our_node_id {
 726                                         path_errs.push(Err(APIError::InvalidRoute{err: "Path went through us but wasn't a simple rebalance loop to us"}));
 727                                         continue 'path_check;
 728                                 }
 729                         }
 730                         total_value += path.last().unwrap().fee_msat;
 731                         path_errs.push(Ok(()));
 732                 }
 733                 if path_errs.iter().any(|e| e.is_err()) {
 734                         return Err(PaymentSendFailure::PathParameterError(path_errs));
 735                 }
 736                 if let Some(amt_msat) = recv_value_msat {
 737                         debug_assert!(amt_msat >= total_value);
 738                         total_value = amt_msat;
 739                 }
 740
 741                 let cur_height = best_block_height + 1;
 742                 let mut results = Vec::new();
 743                 debug_assert_eq!(route.paths.len(), onion_session_privs.len());
 744                 for (path, session_priv) in route.paths.iter().zip(onion_session_privs.into_iter()) {
 745                         let mut path_res = send_payment_along_path(&path, &route.payment_params, &payment_hash, payment_secret, total_value, cur_height, payment_id, &keysend_preimage, session_priv);
 746                         match path_res {
 747                                 Ok(_) => {},
 748                                 Err(APIError::MonitorUpdateInProgress) => {
 749                                         // While a MonitorUpdateInProgress is an Err(_), the payment is still
 750                                         // considered "in flight" and we shouldn't remove it from the
 751                                         // PendingOutboundPayment set.
 752                                 },
 753                                 Err(_) => {
 754                                         let mut pending_outbounds = self.pending_outbound_payments.lock().unwrap();
 755                                         if let Some(payment) = pending_outbounds.get_mut(&payment_id) {
 756                                                 let removed = payment.remove(&session_priv, Some(path));
 757                                                 debug_assert!(removed, "This can't happen as the payment has an entry for this path added by callers");
 758                                         } else {
 759                                                 debug_assert!(false, "This can't happen as the payment was added by callers");
 760                                                 path_res = Err(APIError::APIMisuseError { err: "Internal error: payment disappeared during processing. Please report this bug!".to_owned() });
 761                                         }
 762                                 }
 763                         }
 764                         results.push(path_res);
 765                 }
 766                 let mut has_ok = false;
 767                 let mut has_err = false;
 768                 let mut pending_amt_unsent = 0;
 769                 let mut max_unsent_cltv_delta = 0;
 770                 for (res, path) in results.iter().zip(route.paths.iter()) {
 771                         if res.is_ok() { has_ok = true; }
 772                         if res.is_err() { has_err = true; }
 773                         if let &Err(APIError::MonitorUpdateInProgress) = res {
 774                                 // MonitorUpdateInProgress is inherently unsafe to retry, so we call it a
 775                                 // PartialFailure.
 776                                 has_err = true;
 777                                 has_ok = true;
 778                         } else if res.is_err() {
 779                                 pending_amt_unsent += path.last().unwrap().fee_msat;
 780                                 max_unsent_cltv_delta = cmp::max(max_unsent_cltv_delta, path.last().unwrap().cltv_expiry_delta);
 781                         }
 782                 }
 783                 if has_err && has_ok {
 784                         Err(PaymentSendFailure::PartialFailure {
 785                                 results,
 786                                 payment_id,
 787                                 failed_paths_retry: if pending_amt_unsent != 0 {
 788                                         if let Some(payment_params) = &route.payment_params {
 789                                                 Some(RouteParameters {
 790                                                         payment_params: payment_params.clone(),
 791                                                         final_value_msat: pending_amt_unsent,
 792                                                         final_cltv_expiry_delta: max_unsent_cltv_delta,
 793                                                 })
 794                                         } else { None }
 795                                 } else { None },
 796                         })
 797                 } else if has_err {
 798                         Err(PaymentSendFailure::AllFailedResendSafe(results.drain(..).map(|r| r.unwrap_err()).collect()))
 799                 } else {
 800                         Ok(())
 801                 }
 802         }
 803
 804         #[cfg(test)]
 805         pub(super) fn test_send_payment_internal<NS: Deref, F>(
 806                 &self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>,
 807                 keysend_preimage: Option<PaymentPreimage>, payment_id: PaymentId, recv_value_msat: Option<u64>,
 808                 onion_session_privs: Vec<[u8; 32]>, node_signer: &NS, best_block_height: u32,
 809                 send_payment_along_path: F
 810         ) -> Result<(), PaymentSendFailure>
 811         where
 812                 NS::Target: NodeSigner,
 813                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 814                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 815         {
 816                 self.send_payment_internal(route, payment_hash, payment_secret, keysend_preimage, payment_id,
 817                         recv_value_msat, onion_session_privs, node_signer, best_block_height,
 818                         &send_payment_along_path)
 819                         .map_err(|e| { self.remove_outbound_if_all_failed(payment_id, &e); e })
 820         }
 821
 822         // If we failed to send any paths, we should remove the new PaymentId from the
 823         // `pending_outbound_payments` map, as the user isn't expected to `abandon_payment`.
 824         fn remove_outbound_if_all_failed(&self, payment_id: PaymentId, err: &PaymentSendFailure) {
 825                 if let &PaymentSendFailure::AllFailedResendSafe(_) = err {
 826                         let removed = self.pending_outbound_payments.lock().unwrap().remove(&payment_id).is_some();
 827                         debug_assert!(removed, "We should always have a pending payment to remove here");
 828                 }
 829         }
 830
 831         pub(super) fn claim_htlc<L: Deref>(
 832                 &self, payment_id: PaymentId, payment_preimage: PaymentPreimage, session_priv: SecretKey,
 833                 path: Vec<RouteHop>, from_onchain: bool, pending_events: &Mutex<Vec<events::Event>>, logger: &L
 834         ) where L::Target: Logger {
 835                 let mut session_priv_bytes = [0; 32];
 836                 session_priv_bytes.copy_from_slice(&session_priv[..]);
 837                 let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 838                 let mut pending_events = pending_events.lock().unwrap();
 839                 if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(payment_id) {
 840                         if !payment.get().is_fulfilled() {
 841                                 let payment_hash = PaymentHash(Sha256::hash(&payment_preimage.0).into_inner());
 842                                 let fee_paid_msat = payment.get().get_pending_fee_msat();
 843                                 pending_events.push(
 844                                         events::Event::PaymentSent {
 845                                                 payment_id: Some(payment_id),
 846                                                 payment_preimage,
 847                                                 payment_hash,
 848                                                 fee_paid_msat,
 849                                         }
 850                                 );
 851                                 payment.get_mut().mark_fulfilled();
 852                         }
 853
 854                         if from_onchain {
 855                                 // We currently immediately remove HTLCs which were fulfilled on-chain.
 856                                 // This could potentially lead to removing a pending payment too early,
 857                                 // with a reorg of one block causing us to re-add the fulfilled payment on
 858                                 // restart.
 859                                 // TODO: We should have a second monitor event that informs us of payments
 860                                 // irrevocably fulfilled.
 861                                 if payment.get_mut().remove(&session_priv_bytes, Some(&path)) {
 862                                         let payment_hash = Some(PaymentHash(Sha256::hash(&payment_preimage.0).into_inner()));
 863                                         pending_events.push(
 864                                                 events::Event::PaymentPathSuccessful {
 865                                                         payment_id,
 866                                                         payment_hash,
 867                                                         path,
 868                                                 }
 869                                         );
 870                                 }
 871                         }
 872                 } else {
 873                         log_trace!(logger, "Received duplicative fulfill for HTLC with payment_preimage {}", log_bytes!(payment_preimage.0));
 874                 }
 875         }
 876
 877         pub(super) fn finalize_claims(&self, sources: Vec<HTLCSource>, pending_events: &Mutex<Vec<events::Event>>) {
 878                 let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 879                 let mut pending_events = pending_events.lock().unwrap();
 880                 for source in sources {
 881                         if let HTLCSource::OutboundRoute { session_priv, payment_id, path, .. } = source {
 882                                 let mut session_priv_bytes = [0; 32];
 883                                 session_priv_bytes.copy_from_slice(&session_priv[..]);
 884                                 if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(payment_id) {
 885                                         assert!(payment.get().is_fulfilled());
 886                                         if payment.get_mut().remove(&session_priv_bytes, None) {
 887                                                 pending_events.push(
 888                                                         events::Event::PaymentPathSuccessful {
 889                                                                 payment_id,
 890                                                                 payment_hash: payment.get().payment_hash(),
 891                                                                 path,
 892                                                         }
 893                                                 );
 894                                         }
 895                                 }
 896                         }
 897                 }
 898         }
 899
 900         pub(super) fn remove_stale_resolved_payments(&self, pending_events: &Mutex<Vec<events::Event>>) {
 901                 // If an outbound payment was completed, and no pending HTLCs remain, we should remove it
 902                 // from the map. However, if we did that immediately when the last payment HTLC is claimed,
 903                 // this could race the user making a duplicate send_payment call and our idempotency
 904                 // guarantees would be violated. Instead, we wait a few timer ticks to do the actual
 905                 // removal. This should be more than sufficient to ensure the idempotency of any
 906                 // `send_payment` calls that were made at the same time the `PaymentSent` event was being
 907                 // processed.
 908                 let mut pending_outbound_payments = self.pending_outbound_payments.lock().unwrap();
 909                 let pending_events = pending_events.lock().unwrap();
 910                 pending_outbound_payments.retain(|payment_id, payment| {
 911                         if let PendingOutboundPayment::Fulfilled { session_privs, timer_ticks_without_htlcs, .. } = payment {
 912                                 let mut no_remaining_entries = session_privs.is_empty();
 913                                 if no_remaining_entries {
 914                                         for ev in pending_events.iter() {
 915                                                 match ev {
 916                                                         events::Event::PaymentSent { payment_id: Some(ev_payment_id), .. } |
 917                                                                 events::Event::PaymentPathSuccessful { payment_id: ev_payment_id, .. } |
 918                                                                 events::Event::PaymentPathFailed { payment_id: Some(ev_payment_id), .. } => {
 919                                                                         if payment_id == ev_payment_id {
 920                                                                                 no_remaining_entries = false;
 921                                                                                 break;
 922                                                                         }
 923                                                                 },
 924                                                         _ => {},
 925                                                 }
 926                                         }
 927                                 }
 928                                 if no_remaining_entries {
 929                                         *timer_ticks_without_htlcs += 1;
 930                                         *timer_ticks_without_htlcs <= IDEMPOTENCY_TIMEOUT_TICKS
 931                                 } else {
 932                                         *timer_ticks_without_htlcs = 0;
 933                                         true
 934                                 }
 935                         } else { true }
 936                 });
 937         }
 938
 939         pub(super) fn fail_htlc<L: Deref>(
 940                 &self, source: &HTLCSource, payment_hash: &PaymentHash, onion_error: &HTLCFailReason,
 941                 path: &Vec<RouteHop>, session_priv: &SecretKey, payment_id: &PaymentId,
 942                 payment_params: &Option<PaymentParameters>, probing_cookie_secret: [u8; 32],
 943                 secp_ctx: &Secp256k1<secp256k1::All>, pending_events: &Mutex<Vec<events::Event>>, logger: &L
 944         ) where L::Target: Logger {
 945                 #[cfg(test)]
 946                 let (network_update, short_channel_id, payment_retryable, onion_error_code, onion_error_data) = onion_error.decode_onion_failure(secp_ctx, logger, &source);
 947                 #[cfg(not(test))]
 948                 let (network_update, short_channel_id, payment_retryable, _, _) = onion_error.decode_onion_failure(secp_ctx, logger, &source);
 949
 950                 let mut session_priv_bytes = [0; 32];
 951                 session_priv_bytes.copy_from_slice(&session_priv[..]);
 952                 let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 953                 let mut all_paths_failed = false;
 954                 let mut full_failure_ev = None;
 955                 let mut pending_retry_ev = None;
 956                 let attempts_remaining = if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(*payment_id) {
 957                         if !payment.get_mut().remove(&session_priv_bytes, Some(&path)) {
 958                                 log_trace!(logger, "Received duplicative fail for HTLC with payment_hash {}", log_bytes!(payment_hash.0));
 959                                 return
 960                         }
 961                         if payment.get().is_fulfilled() {
 962                                 log_trace!(logger, "Received failure of HTLC with payment_hash {} after payment completion", log_bytes!(payment_hash.0));
 963                                 return
 964                         }
 965                         let is_retryable_now = payment.get().is_retryable_now();
 966                         if let Some(scid) = short_channel_id {
 967                                 payment.get_mut().insert_previously_failed_scid(scid);
 968                         }
 969                         if payment.get().remaining_parts() == 0 {
 970                                 all_paths_failed = true;
 971                                 if payment.get().abandoned() {
 972                                         full_failure_ev = Some(events::Event::PaymentFailed {
 973                                                 payment_id: *payment_id,
 974                                                 payment_hash: payment.get().payment_hash().expect("PendingOutboundPayments::RetriesExceeded always has a payment hash set"),
 975                                         });
 976                                         payment.remove();
 977                                 }
 978                         }
 979                         is_retryable_now
 980                 } else {
 981                         log_trace!(logger, "Received duplicative fail for HTLC with payment_hash {}", log_bytes!(payment_hash.0));
 982                         return
 983                 };
 984                 core::mem::drop(outbounds);
 985                 let mut retry = if let Some(payment_params_data) = payment_params {
 986                         let path_last_hop = path.last().expect("Outbound payments must have had a valid path");
 987                         Some(RouteParameters {
 988                                 payment_params: payment_params_data.clone(),
 989                                 final_value_msat: path_last_hop.fee_msat,
 990                                 final_cltv_expiry_delta: path_last_hop.cltv_expiry_delta,
 991                         })
 992                 } else { None };
 993                 log_trace!(logger, "Failing outbound payment HTLC with payment_hash {}", log_bytes!(payment_hash.0));
 994
 995                 let path_failure = {
 996                         if payment_is_probe(payment_hash, &payment_id, probing_cookie_secret) {
 997                                 if !payment_retryable {
 998                                         events::Event::ProbeSuccessful {
 999                                                 payment_id: *payment_id,
1000                                                 payment_hash: payment_hash.clone(),
1001                                                 path: path.clone(),
1002                                         }
1003                                 } else {
1004                                         events::Event::ProbeFailed {
1005                                                 payment_id: *payment_id,
1006                                                 payment_hash: payment_hash.clone(),
1007                                                 path: path.clone(),
1008                                                 short_channel_id,
1009                                         }
1010                                 }
1011                         } else {
1012                                 // TODO: If we decided to blame ourselves (or one of our channels) in
1013                                 // process_onion_failure we should close that channel as it implies our
1014                                 // next-hop is needlessly blaming us!
1015                                 if let Some(scid) = short_channel_id {
1016                                         retry.as_mut().map(|r| r.payment_params.previously_failed_channels.push(scid));
1017                                 }
1018                                 if payment_retryable && attempts_remaining && retry.is_some() {
1019                                         debug_assert!(full_failure_ev.is_none());
1020                                         pending_retry_ev = Some(events::Event::PendingHTLCsForwardable {
1021                                                 time_forwardable: Duration::from_millis(MIN_HTLC_RELAY_HOLDING_CELL_MILLIS),
1022                                         });
1023                                 }
1024                                 events::Event::PaymentPathFailed {
1025                                         payment_id: Some(*payment_id),
1026                                         payment_hash: payment_hash.clone(),
1027                                         payment_failed_permanently: !payment_retryable,
1028                                         network_update,
1029                                         all_paths_failed,
1030                                         path: path.clone(),
1031                                         short_channel_id,
1032                                         retry,
1033                                         #[cfg(test)]
1034                                         error_code: onion_error_code,
1035                                         #[cfg(test)]
1036                                         error_data: onion_error_data
1037                                 }
1038                         }
1039                 };
1040                 let mut pending_events = pending_events.lock().unwrap();
1041                 pending_events.push(path_failure);
1042                 if let Some(ev) = full_failure_ev { pending_events.push(ev); }
1043                 if let Some(ev) = pending_retry_ev { pending_events.push(ev); }
1044         }
1045
1046         pub(super) fn abandon_payment(&self, payment_id: PaymentId) -> Option<events::Event> {
1047                 let mut failed_ev = None;
1048                 let mut outbounds = self.pending_outbound_payments.lock().unwrap();
1049                 if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(payment_id) {
1050                         if let Ok(()) = payment.get_mut().mark_abandoned() {
1051                                 if payment.get().remaining_parts() == 0 {
1052                                         failed_ev = Some(events::Event::PaymentFailed {
1053                                                 payment_id,
1054                                                 payment_hash: payment.get().payment_hash().expect("PendingOutboundPayments::RetriesExceeded always has a payment hash set"),
1055                                         });
1056                                         payment.remove();
1057                                 }
1058                         }
1059                 }
1060                 failed_ev
1061         }
1062
1063         #[cfg(test)]
1064         pub fn has_pending_payments(&self) -> bool {
1065                 !self.pending_outbound_payments.lock().unwrap().is_empty()
1066         }
1067
1068         #[cfg(test)]
1069         pub fn clear_pending_payments(&self) {
1070                 self.pending_outbound_payments.lock().unwrap().clear()
1071         }
1072 }
1073
1074 /// Returns whether a payment with the given [`PaymentHash`] and [`PaymentId`] is, in fact, a
1075 /// payment probe.
1076 pub(super) fn payment_is_probe(payment_hash: &PaymentHash, payment_id: &PaymentId,
1077         probing_cookie_secret: [u8; 32]) -> bool
1078 {
1079         let target_payment_hash = probing_cookie_from_id(payment_id, probing_cookie_secret);
1080         target_payment_hash == *payment_hash
1081 }
1082
1083 /// Returns the 'probing cookie' for the given [`PaymentId`].
1084 fn probing_cookie_from_id(payment_id: &PaymentId, probing_cookie_secret: [u8; 32]) -> PaymentHash {
1085         let mut preimage = [0u8; 64];
1086         preimage[..32].copy_from_slice(&probing_cookie_secret);
1087         preimage[32..].copy_from_slice(&payment_id.0);
1088         PaymentHash(Sha256::hash(&preimage).into_inner())
1089 }
1090
1091 impl_writeable_tlv_based_enum_upgradable!(PendingOutboundPayment,
1092         (0, Legacy) => {
1093                 (0, session_privs, required),
1094         },
1095         (1, Fulfilled) => {
1096                 (0, session_privs, required),
1097                 (1, payment_hash, option),
1098                 (3, timer_ticks_without_htlcs, (default_value, 0)),
1099         },
1100         (2, Retryable) => {
1101                 (0, session_privs, required),
1102                 (1, pending_fee_msat, option),
1103                 (2, payment_hash, required),
1104                 (not_written, retry_strategy, (static_value, Retry::Attempts(0))),
1105                 (4, payment_secret, option),
1106                 (not_written, attempts, (static_value, PaymentAttempts::new())),
1107                 (6, total_msat, required),
1108                 (not_written, route_params, (static_value, None)),
1109                 (8, pending_amt_msat, required),
1110                 (10, starting_block_height, required),
1111         },
1112         (3, Abandoned) => {
1113                 (0, session_privs, required),
1114                 (2, payment_hash, required),
1115         },
1116 );