_ 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::channelmanager::MIN_FINAL_CLTV_EXPIRY_DELTA as LDK_DEFAULT_MIN_FINAL_CLTV_EXPIRY_DELTA;
  20 use crate::ln::msgs::DecodeError;
  21 use crate::ln::onion_utils::HTLCFailReason;
  22 use crate::routing::router::{InFlightHtlcs, PaymentParameters, Route, RouteHop, RouteParameters, RoutePath, Router};
  23 use crate::util::errors::APIError;
  24 use crate::util::events;
  25 use crate::util::logger::Logger;
  26 use crate::util::time::Time;
  27 #[cfg(all(not(feature = "no-std"), test))]
  28 use crate::util::time::tests::SinceEpoch;
  29
  30 use core::cmp;
  31 use core::fmt::{self, Display, Formatter};
  32 use core::ops::Deref;
  33 use core::time::Duration;
  34
  35 use crate::prelude::*;
  36 use crate::sync::Mutex;
  37
  38 /// Stores the session_priv for each part of a payment that is still pending. For versions 0.0.102
  39 /// and later, also stores information for retrying the payment.
  40 pub(crate) enum PendingOutboundPayment {
  41         Legacy {
  42                 session_privs: HashSet<[u8; 32]>,
  43         },
  44         Retryable {
  45                 retry_strategy: Option<Retry>,
  46                 attempts: PaymentAttempts,
  47                 payment_params: Option<PaymentParameters>,
  48                 session_privs: HashSet<[u8; 32]>,
  49                 payment_hash: PaymentHash,
  50                 payment_secret: Option<PaymentSecret>,
  51                 keysend_preimage: Option<PaymentPreimage>,
  52                 pending_amt_msat: u64,
  53                 /// Used to track the fee paid. Only present if the payment was serialized on 0.0.103+.
  54                 pending_fee_msat: Option<u64>,
  55                 /// The total payment amount across all paths, used to verify that a retry is not overpaying.
  56                 total_msat: u64,
  57                 /// Our best known block height at the time this payment was initiated.
  58                 starting_block_height: u32,
  59         },
  60         /// When a pending payment is fulfilled, we continue tracking it until all pending HTLCs have
  61         /// been resolved. This ensures we don't look up pending payments in ChannelMonitors on restart
  62         /// and add a pending payment that was already fulfilled.
  63         Fulfilled {
  64                 session_privs: HashSet<[u8; 32]>,
  65                 payment_hash: Option<PaymentHash>,
  66                 timer_ticks_without_htlcs: u8,
  67         },
  68         /// When a payer gives up trying to retry a payment, they inform us, letting us generate a
  69         /// `PaymentFailed` event when all HTLCs have irrevocably failed. This avoids a number of race
  70         /// conditions in MPP-aware payment retriers (1), where the possibility of multiple
  71         /// `PaymentPathFailed` events with `all_paths_failed` can be pending at once, confusing a
  72         /// downstream event handler as to when a payment has actually failed.
  73         ///
  74         /// (1) <https://github.com/lightningdevkit/rust-lightning/issues/1164>
  75         Abandoned {
  76                 session_privs: HashSet<[u8; 32]>,
  77                 payment_hash: PaymentHash,
  78         },
  79 }
  80
  81 impl PendingOutboundPayment {
  82         fn increment_attempts(&mut self) {
  83                 if let PendingOutboundPayment::Retryable { attempts, .. } = self {
  84                         attempts.count += 1;
  85                 }
  86         }
  87         fn is_auto_retryable_now(&self) -> bool {
  88                 match self {
  89                         PendingOutboundPayment::Retryable { retry_strategy: Some(strategy), attempts, .. } => {
  90                                 strategy.is_retryable_now(&attempts)
  91                         },
  92                         _ => false,
  93                 }
  94         }
  95         fn is_retryable_now(&self) -> bool {
  96                 match self {
  97                         PendingOutboundPayment::Retryable { retry_strategy: None, .. } => {
  98                                 // We're handling retries manually, we can always retry.
  99                                 true
 100                         },
 101                         PendingOutboundPayment::Retryable { retry_strategy: Some(strategy), attempts, .. } => {
 102                                 strategy.is_retryable_now(&attempts)
 103                         },
 104                         _ => false,
 105                 }
 106         }
 107         fn payment_parameters(&mut self) -> Option<&mut PaymentParameters> {
 108                 match self {
 109                         PendingOutboundPayment::Retryable { payment_params: Some(ref mut params), .. } => {
 110                                 Some(params)
 111                         },
 112                         _ => None,
 113                 }
 114         }
 115         pub fn insert_previously_failed_scid(&mut self, scid: u64) {
 116                 if let PendingOutboundPayment::Retryable { payment_params: Some(params), .. } = self {
 117                         params.previously_failed_channels.push(scid);
 118                 }
 119         }
 120         pub(super) fn is_fulfilled(&self) -> bool {
 121                 match self {
 122                         PendingOutboundPayment::Fulfilled { .. } => true,
 123                         _ => false,
 124                 }
 125         }
 126         pub(super) fn abandoned(&self) -> bool {
 127                 match self {
 128                         PendingOutboundPayment::Abandoned { .. } => true,
 129                         _ => false,
 130                 }
 131         }
 132         fn get_pending_fee_msat(&self) -> Option<u64> {
 133                 match self {
 134                         PendingOutboundPayment::Retryable { pending_fee_msat, .. } => pending_fee_msat.clone(),
 135                         _ => None,
 136                 }
 137         }
 138
 139         fn payment_hash(&self) -> Option<PaymentHash> {
 140                 match self {
 141                         PendingOutboundPayment::Legacy { .. } => None,
 142                         PendingOutboundPayment::Retryable { payment_hash, .. } => Some(*payment_hash),
 143                         PendingOutboundPayment::Fulfilled { payment_hash, .. } => *payment_hash,
 144                         PendingOutboundPayment::Abandoned { payment_hash, .. } => Some(*payment_hash),
 145                 }
 146         }
 147
 148         fn mark_fulfilled(&mut self) {
 149                 let mut session_privs = HashSet::new();
 150                 core::mem::swap(&mut session_privs, match self {
 151                         PendingOutboundPayment::Legacy { session_privs } |
 152                                 PendingOutboundPayment::Retryable { session_privs, .. } |
 153                                 PendingOutboundPayment::Fulfilled { session_privs, .. } |
 154                                 PendingOutboundPayment::Abandoned { session_privs, .. }
 155                         => session_privs,
 156                 });
 157                 let payment_hash = self.payment_hash();
 158                 *self = PendingOutboundPayment::Fulfilled { session_privs, payment_hash, timer_ticks_without_htlcs: 0 };
 159         }
 160
 161         fn mark_abandoned(&mut self) -> Result<(), ()> {
 162                 let mut session_privs = HashSet::new();
 163                 let our_payment_hash;
 164                 core::mem::swap(&mut session_privs, match self {
 165                         PendingOutboundPayment::Legacy { .. } |
 166                         PendingOutboundPayment::Fulfilled { .. } =>
 167                                 return Err(()),
 168                         PendingOutboundPayment::Retryable { session_privs, payment_hash, .. } |
 169                         PendingOutboundPayment::Abandoned { session_privs, payment_hash, .. } => {
 170                                 our_payment_hash = *payment_hash;
 171                                 session_privs
 172                         },
 173                 });
 174                 *self = PendingOutboundPayment::Abandoned { session_privs, payment_hash: our_payment_hash };
 175                 Ok(())
 176         }
 177
 178         /// panics if path is None and !self.is_fulfilled
 179         fn remove(&mut self, session_priv: &[u8; 32], path: Option<&Vec<RouteHop>>) -> bool {
 180                 let remove_res = match self {
 181                         PendingOutboundPayment::Legacy { session_privs } |
 182                                 PendingOutboundPayment::Retryable { session_privs, .. } |
 183                                 PendingOutboundPayment::Fulfilled { session_privs, .. } |
 184                                 PendingOutboundPayment::Abandoned { session_privs, .. } => {
 185                                         session_privs.remove(session_priv)
 186                                 }
 187                 };
 188                 if remove_res {
 189                         if let PendingOutboundPayment::Retryable { ref mut pending_amt_msat, ref mut pending_fee_msat, .. } = self {
 190                                 let path = path.expect("Fulfilling a payment should always come with a path");
 191                                 let path_last_hop = path.last().expect("Outbound payments must have had a valid path");
 192                                 *pending_amt_msat -= path_last_hop.fee_msat;
 193                                 if let Some(fee_msat) = pending_fee_msat.as_mut() {
 194                                         *fee_msat -= path.get_path_fees();
 195                                 }
 196                         }
 197                 }
 198                 remove_res
 199         }
 200
 201         pub(super) fn insert(&mut self, session_priv: [u8; 32], path: &Vec<RouteHop>) -> bool {
 202                 let insert_res = match self {
 203                         PendingOutboundPayment::Legacy { session_privs } |
 204                                 PendingOutboundPayment::Retryable { session_privs, .. } => {
 205                                         session_privs.insert(session_priv)
 206                                 }
 207                         PendingOutboundPayment::Fulfilled { .. } => false,
 208                         PendingOutboundPayment::Abandoned { .. } => false,
 209                 };
 210                 if insert_res {
 211                         if let PendingOutboundPayment::Retryable { ref mut pending_amt_msat, ref mut pending_fee_msat, .. } = self {
 212                                 let path_last_hop = path.last().expect("Outbound payments must have had a valid path");
 213                                 *pending_amt_msat += path_last_hop.fee_msat;
 214                                 if let Some(fee_msat) = pending_fee_msat.as_mut() {
 215                                         *fee_msat += path.get_path_fees();
 216                                 }
 217                         }
 218                 }
 219                 insert_res
 220         }
 221
 222         pub(super) fn remaining_parts(&self) -> usize {
 223                 match self {
 224                         PendingOutboundPayment::Legacy { session_privs } |
 225                                 PendingOutboundPayment::Retryable { session_privs, .. } |
 226                                 PendingOutboundPayment::Fulfilled { session_privs, .. } |
 227                                 PendingOutboundPayment::Abandoned { session_privs, .. } => {
 228                                         session_privs.len()
 229                                 }
 230                 }
 231         }
 232 }
 233
 234 /// Strategies available to retry payment path failures.
 235 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
 236 pub enum Retry {
 237         /// Max number of attempts to retry payment.
 238         ///
 239         /// Each attempt may be multiple HTLCs along multiple paths if the router decides to split up a
 240         /// retry, and may retry multiple failed HTLCs at once if they failed around the same time and
 241         /// were retried along a route from a single call to [`Router::find_route`].
 242         Attempts(usize),
 243         #[cfg(not(feature = "no-std"))]
 244         /// Time elapsed before abandoning retries for a payment.
 245         Timeout(core::time::Duration),
 246 }
 247
 248 impl Retry {
 249         pub(crate) fn is_retryable_now(&self, attempts: &PaymentAttempts) -> bool {
 250                 match (self, attempts) {
 251                         (Retry::Attempts(max_retry_count), PaymentAttempts { count, .. }) => {
 252                                 max_retry_count > count
 253                         },
 254                         #[cfg(all(not(feature = "no-std"), not(test)))]
 255                         (Retry::Timeout(max_duration), PaymentAttempts { first_attempted_at, .. }) =>
 256                                 *max_duration >= std::time::Instant::now().duration_since(*first_attempted_at),
 257                         #[cfg(all(not(feature = "no-std"), test))]
 258                         (Retry::Timeout(max_duration), PaymentAttempts { first_attempted_at, .. }) =>
 259                                 *max_duration >= SinceEpoch::now().duration_since(*first_attempted_at),
 260                 }
 261         }
 262 }
 263
 264 #[cfg(feature = "std")]
 265 pub(super) fn has_expired(route_params: &RouteParameters) -> bool {
 266         if let Some(expiry_time) = route_params.payment_params.expiry_time {
 267                 if let Ok(elapsed) = std::time::SystemTime::UNIX_EPOCH.elapsed() {
 268                         return elapsed > core::time::Duration::from_secs(expiry_time)
 269                 }
 270         }
 271         false
 272 }
 273
 274 pub(crate) type PaymentAttempts = PaymentAttemptsUsingTime<ConfiguredTime>;
 275
 276 /// Storing minimal payment attempts information required for determining if a outbound payment can
 277 /// be retried.
 278 pub(crate) struct PaymentAttemptsUsingTime<T: Time> {
 279         /// This count will be incremented only after the result of the attempt is known. When it's 0,
 280         /// it means the result of the first attempt is not known yet.
 281         pub(crate) count: usize,
 282         /// This field is only used when retry is `Retry::Timeout` which is only build with feature std
 283         first_attempted_at: T
 284 }
 285
 286 #[cfg(not(any(feature = "no-std", test)))]
 287 type ConfiguredTime = std::time::Instant;
 288 #[cfg(feature = "no-std")]
 289 type ConfiguredTime = crate::util::time::Eternity;
 290 #[cfg(all(not(feature = "no-std"), test))]
 291 type ConfiguredTime = SinceEpoch;
 292
 293 impl<T: Time> PaymentAttemptsUsingTime<T> {
 294         pub(crate) fn new() -> Self {
 295                 PaymentAttemptsUsingTime {
 296                         count: 0,
 297                         first_attempted_at: T::now()
 298                 }
 299         }
 300 }
 301
 302 impl<T: Time> Display for PaymentAttemptsUsingTime<T> {
 303         fn fmt(&self, f: &mut Formatter) -> Result<(), fmt::Error> {
 304                 #[cfg(feature = "no-std")]
 305                 return write!(f, "attempts: {}", self.count);
 306                 #[cfg(not(feature = "no-std"))]
 307                 return write!(
 308                         f,
 309                         "attempts: {}, duration: {}s",
 310                         self.count,
 311                         T::now().duration_since(self.first_attempted_at).as_secs()
 312                 );
 313         }
 314 }
 315
 316 /// If a payment fails to send, it can be in one of several states. This enum is returned as the
 317 /// Err() type describing which state the payment is in, see the description of individual enum
 318 /// states for more.
 319 #[derive(Clone, Debug)]
 320 pub enum PaymentSendFailure {
 321         /// A parameter which was passed to send_payment was invalid, preventing us from attempting to
 322         /// send the payment at all.
 323         ///
 324         /// You can freely resend the payment in full (with the parameter error fixed).
 325         ///
 326         /// Because the payment failed outright, no payment tracking is done and no
 327         /// [`Event::PaymentPathFailed`] or [`Event::PaymentFailed`] events will be generated.
 328         ///
 329         /// [`Event::PaymentPathFailed`]: crate::util::events::Event::PaymentPathFailed
 330         /// [`Event::PaymentFailed`]: crate::util::events::Event::PaymentFailed
 331         ParameterError(APIError),
 332         /// A parameter in a single path which was passed to send_payment was invalid, preventing us
 333         /// from attempting to send the payment at all.
 334         ///
 335         /// You can freely resend the payment in full (with the parameter error fixed).
 336         ///
 337         /// Because the payment failed outright, no payment tracking is done and no
 338         /// [`Event::PaymentPathFailed`] or [`Event::PaymentFailed`] events will be generated.
 339         ///
 340         /// The results here are ordered the same as the paths in the route object which was passed to
 341         /// send_payment.
 342         ///
 343         /// [`Event::PaymentPathFailed`]: crate::util::events::Event::PaymentPathFailed
 344         /// [`Event::PaymentFailed`]: crate::util::events::Event::PaymentFailed
 345         PathParameterError(Vec<Result<(), APIError>>),
 346         /// All paths which were attempted failed to send, with no channel state change taking place.
 347         /// You can freely resend the payment in full (though you probably want to do so over different
 348         /// paths than the ones selected).
 349         ///
 350         /// Because the payment failed outright, no payment tracking is done and no
 351         /// [`Event::PaymentPathFailed`] or [`Event::PaymentFailed`] events will be generated.
 352         ///
 353         /// [`Event::PaymentPathFailed`]: crate::util::events::Event::PaymentPathFailed
 354         /// [`Event::PaymentFailed`]: crate::util::events::Event::PaymentFailed
 355         AllFailedResendSafe(Vec<APIError>),
 356         /// Indicates that a payment for the provided [`PaymentId`] is already in-flight and has not
 357         /// yet completed (i.e. generated an [`Event::PaymentSent`] or [`Event::PaymentFailed`]).
 358         ///
 359         /// [`PaymentId`]: crate::ln::channelmanager::PaymentId
 360         /// [`Event::PaymentSent`]: crate::util::events::Event::PaymentSent
 361         /// [`Event::PaymentFailed`]: crate::util::events::Event::PaymentFailed
 362         DuplicatePayment,
 363         /// Some paths which were attempted failed to send, though possibly not all. At least some
 364         /// paths have irrevocably committed to the HTLC.
 365         ///
 366         /// The results here are ordered the same as the paths in the route object which was passed to
 367         /// send_payment.
 368         ///
 369         /// Any entries which contain `Err(APIError::MonitorUpdateInprogress)` will send once a
 370         /// [`MonitorEvent::Completed`] is provided for the next-hop channel with the latest update_id.
 371         ///
 372         /// [`MonitorEvent::Completed`]: crate::chain::channelmonitor::MonitorEvent::Completed
 373         PartialFailure {
 374                 /// The errors themselves, in the same order as the paths from the route.
 375                 results: Vec<Result<(), APIError>>,
 376                 /// If some paths failed without irrevocably committing to the new HTLC(s), this will
 377                 /// contain a [`RouteParameters`] object for the failing paths.
 378                 failed_paths_retry: Option<RouteParameters>,
 379                 /// The payment id for the payment, which is now at least partially pending.
 380                 payment_id: PaymentId,
 381         },
 382 }
 383
 384 pub(super) struct OutboundPayments {
 385         pub(super) pending_outbound_payments: Mutex<HashMap<PaymentId, PendingOutboundPayment>>,
 386 }
 387
 388 impl OutboundPayments {
 389         pub(super) fn new() -> Self {
 390                 Self {
 391                         pending_outbound_payments: Mutex::new(HashMap::new())
 392                 }
 393         }
 394
 395         pub(super) fn send_payment<R: Deref, ES: Deref, NS: Deref, IH, SP, L: Deref>(
 396                 &self, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>, payment_id: PaymentId,
 397                 retry_strategy: Retry, route_params: RouteParameters, router: &R,
 398                 first_hops: Vec<ChannelDetails>, compute_inflight_htlcs: IH, entropy_source: &ES,
 399                 node_signer: &NS, best_block_height: u32, logger: &L, send_payment_along_path: SP,
 400         ) -> Result<(), PaymentSendFailure>
 401         where
 402                 R::Target: Router,
 403                 ES::Target: EntropySource,
 404                 NS::Target: NodeSigner,
 405                 L::Target: Logger,
 406                 IH: Fn() -> InFlightHtlcs,
 407                 SP: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 408                          u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>,
 409         {
 410                 self.pay_internal(payment_id, Some((payment_hash, payment_secret, None, retry_strategy)),
 411                         route_params, router, first_hops, &compute_inflight_htlcs, entropy_source, node_signer,
 412                         best_block_height, logger, &send_payment_along_path)
 413                         .map_err(|e| { self.remove_outbound_if_all_failed(payment_id, &e); e })
 414         }
 415
 416         pub(super) fn send_payment_with_route<ES: Deref, NS: Deref, F>(
 417                 &self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>,
 418                 payment_id: PaymentId, entropy_source: &ES, node_signer: &NS, best_block_height: u32,
 419                 send_payment_along_path: F
 420         ) -> Result<(), 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 onion_session_privs = self.add_new_pending_payment(payment_hash, *payment_secret, payment_id, None, route, None, None, entropy_source, best_block_height)?;
 428                 self.pay_route_internal(route, payment_hash, payment_secret, None, payment_id, None,
 429                         onion_session_privs, node_signer, best_block_height, &send_payment_along_path)
 430                         .map_err(|e| { self.remove_outbound_if_all_failed(payment_id, &e); e })
 431         }
 432
 433         pub(super) fn send_spontaneous_payment<R: Deref, ES: Deref, NS: Deref, IH, SP, L: Deref>(
 434                 &self, payment_preimage: Option<PaymentPreimage>, payment_id: PaymentId,
 435                 retry_strategy: Retry, route_params: RouteParameters, router: &R,
 436                 first_hops: Vec<ChannelDetails>, inflight_htlcs: IH, entropy_source: &ES,
 437                 node_signer: &NS, best_block_height: u32, logger: &L, send_payment_along_path: SP
 438         ) -> Result<PaymentHash, PaymentSendFailure>
 439         where
 440                 R::Target: Router,
 441                 ES::Target: EntropySource,
 442                 NS::Target: NodeSigner,
 443                 L::Target: Logger,
 444                 IH: Fn() -> InFlightHtlcs,
 445                 SP: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 446                          u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>,
 447         {
 448                 let preimage = payment_preimage
 449                         .unwrap_or_else(|| PaymentPreimage(entropy_source.get_secure_random_bytes()));
 450                 let payment_hash = PaymentHash(Sha256::hash(&preimage.0).into_inner());
 451                 self.pay_internal(payment_id, Some((payment_hash, &None, Some(preimage), retry_strategy)),
 452                         route_params, router, first_hops, &inflight_htlcs, entropy_source, node_signer,
 453                         best_block_height, logger, &send_payment_along_path)
 454                         .map(|()| payment_hash)
 455                         .map_err(|e| { self.remove_outbound_if_all_failed(payment_id, &e); e })
 456         }
 457
 458         pub(super) fn send_spontaneous_payment_with_route<ES: Deref, NS: Deref, F>(
 459                 &self, route: &Route, payment_preimage: Option<PaymentPreimage>, payment_id: PaymentId,
 460                 entropy_source: &ES, node_signer: &NS, best_block_height: u32, send_payment_along_path: F
 461         ) -> Result<PaymentHash, PaymentSendFailure>
 462         where
 463                 ES::Target: EntropySource,
 464                 NS::Target: NodeSigner,
 465                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 466                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 467         {
 468                 let preimage = payment_preimage
 469                         .unwrap_or_else(|| PaymentPreimage(entropy_source.get_secure_random_bytes()));
 470                 let payment_hash = PaymentHash(Sha256::hash(&preimage.0).into_inner());
 471                 let onion_session_privs = self.add_new_pending_payment(payment_hash, None, payment_id, Some(preimage), &route, None, None, entropy_source, best_block_height)?;
 472
 473                 match self.pay_route_internal(route, payment_hash, &None, Some(preimage), payment_id, None, onion_session_privs, node_signer, best_block_height, &send_payment_along_path) {
 474                         Ok(()) => Ok(payment_hash),
 475                         Err(e) => {
 476                                 self.remove_outbound_if_all_failed(payment_id, &e);
 477                                 Err(e)
 478                         }
 479                 }
 480         }
 481
 482         pub(super) fn check_retry_payments<R: Deref, ES: Deref, NS: Deref, SP, IH, FH, L: Deref>(
 483                 &self, router: &R, first_hops: FH, inflight_htlcs: IH, entropy_source: &ES, node_signer: &NS,
 484                 best_block_height: u32, pending_events: &Mutex<Vec<events::Event>>, logger: &L,
 485                 send_payment_along_path: SP,
 486         )
 487         where
 488                 R::Target: Router,
 489                 ES::Target: EntropySource,
 490                 NS::Target: NodeSigner,
 491                 SP: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 492                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>,
 493                 IH: Fn() -> InFlightHtlcs,
 494                 FH: Fn() -> Vec<ChannelDetails>,
 495                 L::Target: Logger,
 496         {
 497                 loop {
 498                         let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 499                         let mut retry_id_route_params = None;
 500                         for (pmt_id, pmt) in outbounds.iter_mut() {
 501                                 if pmt.is_auto_retryable_now() {
 502                                         if let PendingOutboundPayment::Retryable { pending_amt_msat, total_msat, payment_params: Some(params), .. } = pmt {
 503                                                 if pending_amt_msat < total_msat {
 504                                                         retry_id_route_params = Some((*pmt_id, RouteParameters {
 505                                                                 final_value_msat: *total_msat - *pending_amt_msat,
 506                                                                 final_cltv_expiry_delta:
 507                                                                         if let Some(delta) = params.final_cltv_expiry_delta { delta }
 508                                                                         else {
 509                                                                                 debug_assert!(false, "We always set the final_cltv_expiry_delta when a path fails");
 510                                                                                 LDK_DEFAULT_MIN_FINAL_CLTV_EXPIRY_DELTA.into()
 511                                                                         },
 512                                                                 payment_params: params.clone(),
 513                                                         }));
 514                                                         break
 515                                                 }
 516                                         }
 517                                 }
 518                         }
 519                         core::mem::drop(outbounds);
 520                         if let Some((payment_id, route_params)) = retry_id_route_params {
 521                                 if let Err(e) = self.pay_internal(payment_id, None, route_params, router, first_hops(), &inflight_htlcs, entropy_source, node_signer, best_block_height, logger, &send_payment_along_path) {
 522                                         log_info!(logger, "Errored retrying payment: {:?}", e);
 523                                         // If we error on retry, there is no chance of the payment succeeding and no HTLCs have
 524                                         // been irrevocably committed to, so we can safely abandon.
 525                                         self.abandon_payment(payment_id, pending_events);
 526                                 }
 527                         } else { break }
 528                 }
 529
 530                 let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 531                 outbounds.retain(|pmt_id, pmt| {
 532                         let mut retain = true;
 533                         if !pmt.is_auto_retryable_now() && pmt.remaining_parts() == 0 {
 534                                 if pmt.mark_abandoned().is_ok() {
 535                                         pending_events.lock().unwrap().push(events::Event::PaymentFailed {
 536                                                 payment_id: *pmt_id,
 537                                                 payment_hash: pmt.payment_hash().expect("PendingOutboundPayments::Retryable always has a payment hash set"),
 538                                         });
 539                                         retain = false;
 540                                 }
 541                         }
 542                         retain
 543                 });
 544         }
 545
 546         /// Will return `Ok(())` iff at least one HTLC is sent for the payment.
 547         fn pay_internal<R: Deref, NS: Deref, ES: Deref, IH, SP, L: Deref>(
 548                 &self, payment_id: PaymentId,
 549                 initial_send_info: Option<(PaymentHash, &Option<PaymentSecret>, Option<PaymentPreimage>, Retry)>,
 550                 route_params: RouteParameters, router: &R, first_hops: Vec<ChannelDetails>,
 551                 inflight_htlcs: &IH, entropy_source: &ES, node_signer: &NS, best_block_height: u32,
 552                 logger: &L, send_payment_along_path: &SP,
 553         ) -> Result<(), PaymentSendFailure>
 554         where
 555                 R::Target: Router,
 556                 ES::Target: EntropySource,
 557                 NS::Target: NodeSigner,
 558                 L::Target: Logger,
 559                 IH: Fn() -> InFlightHtlcs,
 560                 SP: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 561                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 562         {
 563                 #[cfg(feature = "std")] {
 564                         if has_expired(&route_params) {
 565                                 return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 566                                         err: format!("Invoice expired for payment id {}", log_bytes!(payment_id.0)),
 567                                 }))
 568                         }
 569                 }
 570
 571                 let route = router.find_route(
 572                         &node_signer.get_node_id(Recipient::Node).unwrap(), &route_params,
 573                         Some(&first_hops.iter().collect::<Vec<_>>()), &inflight_htlcs(),
 574                 ).map_err(|e| PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 575                         err: format!("Failed to find a route for payment {}: {:?}", log_bytes!(payment_id.0), e), // TODO: add APIError::RouteNotFound
 576                 }))?;
 577
 578                 let res = if let Some((payment_hash, payment_secret, keysend_preimage, retry_strategy)) = initial_send_info {
 579                         let onion_session_privs = self.add_new_pending_payment(payment_hash, *payment_secret, payment_id, keysend_preimage, &route, Some(retry_strategy), Some(route_params.payment_params.clone()), entropy_source, best_block_height)?;
 580                         self.pay_route_internal(&route, payment_hash, payment_secret, None, payment_id, None, onion_session_privs, node_signer, best_block_height, send_payment_along_path)
 581                 } else {
 582                         self.retry_payment_with_route(&route, payment_id, entropy_source, node_signer, best_block_height, send_payment_along_path)
 583                 };
 584                 match res {
 585                         Err(PaymentSendFailure::AllFailedResendSafe(_)) => {
 586                                 let retry_res = self.pay_internal(payment_id, None, route_params, router, first_hops, inflight_htlcs, entropy_source, node_signer, best_block_height, logger, send_payment_along_path);
 587                                 log_info!(logger, "Result retrying payment id {}: {:?}", log_bytes!(payment_id.0), retry_res);
 588                                 if let Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError { err })) = &retry_res {
 589                                         if err.starts_with("Retries exhausted ") { return res; }
 590                                 }
 591                                 retry_res
 592                         },
 593                         Err(PaymentSendFailure::PartialFailure { failed_paths_retry: Some(retry), .. }) => {
 594                                 // Some paths were sent, even if we failed to send the full MPP value our recipient may
 595                                 // misbehave and claim the funds, at which point we have to consider the payment sent, so
 596                                 // return `Ok()` here, ignoring any retry errors.
 597                                 let retry_res = self.pay_internal(payment_id, None, retry, router, first_hops, inflight_htlcs, entropy_source, node_signer, best_block_height, logger, send_payment_along_path);
 598                                 log_info!(logger, "Result retrying payment id {}: {:?}", log_bytes!(payment_id.0), retry_res);
 599                                 Ok(())
 600                         },
 601                         Err(PaymentSendFailure::PartialFailure { failed_paths_retry: None, .. }) => {
 602                                 // This may happen if we send a payment and some paths fail, but only due to a temporary
 603                                 // monitor failure or the like, implying they're really in-flight, but we haven't sent the
 604                                 // initial HTLC-Add messages yet.
 605                                 Ok(())
 606                         },
 607                         res => res,
 608                 }
 609         }
 610
 611         pub(super) fn retry_payment_with_route<ES: Deref, NS: Deref, F>(
 612                 &self, route: &Route, payment_id: PaymentId, entropy_source: &ES, node_signer: &NS, best_block_height: u32,
 613                 send_payment_along_path: F
 614         ) -> Result<(), PaymentSendFailure>
 615         where
 616                 ES::Target: EntropySource,
 617                 NS::Target: NodeSigner,
 618                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 619                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 620         {
 621                 const RETRY_OVERFLOW_PERCENTAGE: u64 = 10;
 622                 for path in route.paths.iter() {
 623                         if path.len() == 0 {
 624                                 return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 625                                         err: "length-0 path in route".to_string()
 626                                 }))
 627                         }
 628                 }
 629
 630                 let mut onion_session_privs = Vec::with_capacity(route.paths.len());
 631                 for _ in 0..route.paths.len() {
 632                         onion_session_privs.push(entropy_source.get_secure_random_bytes());
 633                 }
 634
 635                 let (total_msat, payment_hash, payment_secret, keysend_preimage) = {
 636                         let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 637                         match outbounds.get_mut(&payment_id) {
 638                                 Some(payment) => {
 639                                         let res = match payment {
 640                                                 PendingOutboundPayment::Retryable {
 641                                                         total_msat, payment_hash, keysend_preimage, payment_secret, pending_amt_msat, ..
 642                                                 } => {
 643                                                         let retry_amt_msat: u64 = route.paths.iter().map(|path| path.last().unwrap().fee_msat).sum();
 644                                                         if retry_amt_msat + *pending_amt_msat > *total_msat * (100 + RETRY_OVERFLOW_PERCENTAGE) / 100 {
 645                                                                 return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 646                                                                         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()
 647                                                                 }))
 648                                                         }
 649                                                         (*total_msat, *payment_hash, *payment_secret, *keysend_preimage)
 650                                                 },
 651                                                 PendingOutboundPayment::Legacy { .. } => {
 652                                                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 653                                                                 err: "Unable to retry payments that were initially sent on LDK versions prior to 0.0.102".to_string()
 654                                                         }))
 655                                                 },
 656                                                 PendingOutboundPayment::Fulfilled { .. } => {
 657                                                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 658                                                                 err: "Payment already completed".to_owned()
 659                                                         }));
 660                                                 },
 661                                                 PendingOutboundPayment::Abandoned { .. } => {
 662                                                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 663                                                                 err: "Payment already abandoned (with some HTLCs still pending)".to_owned()
 664                                                         }));
 665                                                 },
 666                                         };
 667                                         if !payment.is_retryable_now() {
 668                                                 return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 669                                                         err: format!("Retries exhausted for payment id {}", log_bytes!(payment_id.0)),
 670                                                 }))
 671                                         }
 672                                         payment.increment_attempts();
 673                                         for (path, session_priv_bytes) in route.paths.iter().zip(onion_session_privs.iter()) {
 674                                                 assert!(payment.insert(*session_priv_bytes, path));
 675                                         }
 676                                         res
 677                                 },
 678                                 None =>
 679                                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 680                                                 err: format!("Payment with ID {} not found", log_bytes!(payment_id.0)),
 681                                         })),
 682                         }
 683                 };
 684                 self.pay_route_internal(route, payment_hash, &payment_secret, keysend_preimage, payment_id, Some(total_msat), onion_session_privs, node_signer, best_block_height, &send_payment_along_path)
 685         }
 686
 687         pub(super) fn send_probe<ES: Deref, NS: Deref, F>(
 688                 &self, hops: Vec<RouteHop>, probing_cookie_secret: [u8; 32], entropy_source: &ES,
 689                 node_signer: &NS, best_block_height: u32, send_payment_along_path: F
 690         ) -> Result<(PaymentHash, PaymentId), PaymentSendFailure>
 691         where
 692                 ES::Target: EntropySource,
 693                 NS::Target: NodeSigner,
 694                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 695                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 696         {
 697                 let payment_id = PaymentId(entropy_source.get_secure_random_bytes());
 698
 699                 let payment_hash = probing_cookie_from_id(&payment_id, probing_cookie_secret);
 700
 701                 if hops.len() < 2 {
 702                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 703                                 err: "No need probing a path with less than two hops".to_string()
 704                         }))
 705                 }
 706
 707                 let route = Route { paths: vec![hops], payment_params: None };
 708                 let onion_session_privs = self.add_new_pending_payment(payment_hash, None, payment_id, None, &route, None, None, entropy_source, best_block_height)?;
 709
 710                 match self.pay_route_internal(&route, payment_hash, &None, None, payment_id, None, onion_session_privs, node_signer, best_block_height, &send_payment_along_path) {
 711                         Ok(()) => Ok((payment_hash, payment_id)),
 712                         Err(e) => {
 713                                 self.remove_outbound_if_all_failed(payment_id, &e);
 714                                 Err(e)
 715                         }
 716                 }
 717         }
 718
 719         #[cfg(test)]
 720         pub(super) fn test_add_new_pending_payment<ES: Deref>(
 721                 &self, payment_hash: PaymentHash, payment_secret: Option<PaymentSecret>, payment_id: PaymentId,
 722                 route: &Route, retry_strategy: Option<Retry>, entropy_source: &ES, best_block_height: u32
 723         ) -> Result<Vec<[u8; 32]>, PaymentSendFailure> where ES::Target: EntropySource {
 724                 self.add_new_pending_payment(payment_hash, payment_secret, payment_id, None, route, retry_strategy, None, entropy_source, best_block_height)
 725         }
 726
 727         pub(super) fn add_new_pending_payment<ES: Deref>(
 728                 &self, payment_hash: PaymentHash, payment_secret: Option<PaymentSecret>, payment_id: PaymentId,
 729                 keysend_preimage: Option<PaymentPreimage>, route: &Route, retry_strategy: Option<Retry>,
 730                 payment_params: Option<PaymentParameters>, entropy_source: &ES, best_block_height: u32
 731         ) -> Result<Vec<[u8; 32]>, PaymentSendFailure> where ES::Target: EntropySource {
 732                 let mut onion_session_privs = Vec::with_capacity(route.paths.len());
 733                 for _ in 0..route.paths.len() {
 734                         onion_session_privs.push(entropy_source.get_secure_random_bytes());
 735                 }
 736
 737                 let mut pending_outbounds = self.pending_outbound_payments.lock().unwrap();
 738                 match pending_outbounds.entry(payment_id) {
 739                         hash_map::Entry::Occupied(_) => Err(PaymentSendFailure::DuplicatePayment),
 740                         hash_map::Entry::Vacant(entry) => {
 741                                 let payment = entry.insert(PendingOutboundPayment::Retryable {
 742                                         retry_strategy,
 743                                         attempts: PaymentAttempts::new(),
 744                                         payment_params,
 745                                         session_privs: HashSet::new(),
 746                                         pending_amt_msat: 0,
 747                                         pending_fee_msat: Some(0),
 748                                         payment_hash,
 749                                         payment_secret,
 750                                         keysend_preimage,
 751                                         starting_block_height: best_block_height,
 752                                         total_msat: route.get_total_amount(),
 753                                 });
 754
 755                                 for (path, session_priv_bytes) in route.paths.iter().zip(onion_session_privs.iter()) {
 756                                         assert!(payment.insert(*session_priv_bytes, path));
 757                                 }
 758
 759                                 Ok(onion_session_privs)
 760                         },
 761                 }
 762         }
 763
 764         fn pay_route_internal<NS: Deref, F>(
 765                 &self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>,
 766                 keysend_preimage: Option<PaymentPreimage>, payment_id: PaymentId, recv_value_msat: Option<u64>,
 767                 onion_session_privs: Vec<[u8; 32]>, node_signer: &NS, best_block_height: u32,
 768                 send_payment_along_path: &F
 769         ) -> Result<(), PaymentSendFailure>
 770         where
 771                 NS::Target: NodeSigner,
 772                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 773                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 774         {
 775                 if route.paths.len() < 1 {
 776                         return Err(PaymentSendFailure::ParameterError(APIError::InvalidRoute{err: "There must be at least one path to send over"}));
 777                 }
 778                 if payment_secret.is_none() && route.paths.len() > 1 {
 779                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError{err: "Payment secret is required for multi-path payments".to_string()}));
 780                 }
 781                 let mut total_value = 0;
 782                 let our_node_id = node_signer.get_node_id(Recipient::Node).unwrap(); // TODO no unwrap
 783                 let mut path_errs = Vec::with_capacity(route.paths.len());
 784                 'path_check: for path in route.paths.iter() {
 785                         if path.len() < 1 || path.len() > 20 {
 786                                 path_errs.push(Err(APIError::InvalidRoute{err: "Path didn't go anywhere/had bogus size"}));
 787                                 continue 'path_check;
 788                         }
 789                         for (idx, hop) in path.iter().enumerate() {
 790                                 if idx != path.len() - 1 && hop.pubkey == our_node_id {
 791                                         path_errs.push(Err(APIError::InvalidRoute{err: "Path went through us but wasn't a simple rebalance loop to us"}));
 792                                         continue 'path_check;
 793                                 }
 794                         }
 795                         total_value += path.last().unwrap().fee_msat;
 796                         path_errs.push(Ok(()));
 797                 }
 798                 if path_errs.iter().any(|e| e.is_err()) {
 799                         return Err(PaymentSendFailure::PathParameterError(path_errs));
 800                 }
 801                 if let Some(amt_msat) = recv_value_msat {
 802                         debug_assert!(amt_msat >= total_value);
 803                         total_value = amt_msat;
 804                 }
 805
 806                 let cur_height = best_block_height + 1;
 807                 let mut results = Vec::new();
 808                 debug_assert_eq!(route.paths.len(), onion_session_privs.len());
 809                 for (path, session_priv) in route.paths.iter().zip(onion_session_privs.into_iter()) {
 810                         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);
 811                         match path_res {
 812                                 Ok(_) => {},
 813                                 Err(APIError::MonitorUpdateInProgress) => {
 814                                         // While a MonitorUpdateInProgress is an Err(_), the payment is still
 815                                         // considered "in flight" and we shouldn't remove it from the
 816                                         // PendingOutboundPayment set.
 817                                 },
 818                                 Err(_) => {
 819                                         let mut pending_outbounds = self.pending_outbound_payments.lock().unwrap();
 820                                         if let Some(payment) = pending_outbounds.get_mut(&payment_id) {
 821                                                 let removed = payment.remove(&session_priv, Some(path));
 822                                                 debug_assert!(removed, "This can't happen as the payment has an entry for this path added by callers");
 823                                         } else {
 824                                                 debug_assert!(false, "This can't happen as the payment was added by callers");
 825                                                 path_res = Err(APIError::APIMisuseError { err: "Internal error: payment disappeared during processing. Please report this bug!".to_owned() });
 826                                         }
 827                                 }
 828                         }
 829                         results.push(path_res);
 830                 }
 831                 let mut has_ok = false;
 832                 let mut has_err = false;
 833                 let mut pending_amt_unsent = 0;
 834                 let mut max_unsent_cltv_delta = 0;
 835                 for (res, path) in results.iter().zip(route.paths.iter()) {
 836                         if res.is_ok() { has_ok = true; }
 837                         if res.is_err() { has_err = true; }
 838                         if let &Err(APIError::MonitorUpdateInProgress) = res {
 839                                 // MonitorUpdateInProgress is inherently unsafe to retry, so we call it a
 840                                 // PartialFailure.
 841                                 has_err = true;
 842                                 has_ok = true;
 843                         } else if res.is_err() {
 844                                 pending_amt_unsent += path.last().unwrap().fee_msat;
 845                                 max_unsent_cltv_delta = cmp::max(max_unsent_cltv_delta, path.last().unwrap().cltv_expiry_delta);
 846                         }
 847                 }
 848                 if has_err && has_ok {
 849                         Err(PaymentSendFailure::PartialFailure {
 850                                 results,
 851                                 payment_id,
 852                                 failed_paths_retry: if pending_amt_unsent != 0 {
 853                                         if let Some(payment_params) = &route.payment_params {
 854                                                 Some(RouteParameters {
 855                                                         payment_params: payment_params.clone(),
 856                                                         final_value_msat: pending_amt_unsent,
 857                                                         final_cltv_expiry_delta:
 858                                                                 if let Some(delta) = payment_params.final_cltv_expiry_delta { delta }
 859                                                                 else { max_unsent_cltv_delta },
 860                                                 })
 861                                         } else { None }
 862                                 } else { None },
 863                         })
 864                 } else if has_err {
 865                         Err(PaymentSendFailure::AllFailedResendSafe(results.drain(..).map(|r| r.unwrap_err()).collect()))
 866                 } else {
 867                         Ok(())
 868                 }
 869         }
 870
 871         #[cfg(test)]
 872         pub(super) fn test_send_payment_internal<NS: Deref, F>(
 873                 &self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>,
 874                 keysend_preimage: Option<PaymentPreimage>, payment_id: PaymentId, recv_value_msat: Option<u64>,
 875                 onion_session_privs: Vec<[u8; 32]>, node_signer: &NS, best_block_height: u32,
 876                 send_payment_along_path: F
 877         ) -> Result<(), PaymentSendFailure>
 878         where
 879                 NS::Target: NodeSigner,
 880                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 881                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 882         {
 883                 self.pay_route_internal(route, payment_hash, payment_secret, keysend_preimage, payment_id,
 884                         recv_value_msat, onion_session_privs, node_signer, best_block_height,
 885                         &send_payment_along_path)
 886                         .map_err(|e| { self.remove_outbound_if_all_failed(payment_id, &e); e })
 887         }
 888
 889         // If we failed to send any paths, remove the new PaymentId from the `pending_outbound_payments`
 890         // map as the payment is free to be resent.
 891         fn remove_outbound_if_all_failed(&self, payment_id: PaymentId, err: &PaymentSendFailure) {
 892                 if let &PaymentSendFailure::AllFailedResendSafe(_) = err {
 893                         let removed = self.pending_outbound_payments.lock().unwrap().remove(&payment_id).is_some();
 894                         debug_assert!(removed, "We should always have a pending payment to remove here");
 895                 }
 896         }
 897
 898         pub(super) fn claim_htlc<L: Deref>(
 899                 &self, payment_id: PaymentId, payment_preimage: PaymentPreimage, session_priv: SecretKey,
 900                 path: Vec<RouteHop>, from_onchain: bool, pending_events: &Mutex<Vec<events::Event>>, logger: &L
 901         ) where L::Target: Logger {
 902                 let mut session_priv_bytes = [0; 32];
 903                 session_priv_bytes.copy_from_slice(&session_priv[..]);
 904                 let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 905                 let mut pending_events = pending_events.lock().unwrap();
 906                 if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(payment_id) {
 907                         if !payment.get().is_fulfilled() {
 908                                 let payment_hash = PaymentHash(Sha256::hash(&payment_preimage.0).into_inner());
 909                                 let fee_paid_msat = payment.get().get_pending_fee_msat();
 910                                 pending_events.push(
 911                                         events::Event::PaymentSent {
 912                                                 payment_id: Some(payment_id),
 913                                                 payment_preimage,
 914                                                 payment_hash,
 915                                                 fee_paid_msat,
 916                                         }
 917                                 );
 918                                 payment.get_mut().mark_fulfilled();
 919                         }
 920
 921                         if from_onchain {
 922                                 // We currently immediately remove HTLCs which were fulfilled on-chain.
 923                                 // This could potentially lead to removing a pending payment too early,
 924                                 // with a reorg of one block causing us to re-add the fulfilled payment on
 925                                 // restart.
 926                                 // TODO: We should have a second monitor event that informs us of payments
 927                                 // irrevocably fulfilled.
 928                                 if payment.get_mut().remove(&session_priv_bytes, Some(&path)) {
 929                                         let payment_hash = Some(PaymentHash(Sha256::hash(&payment_preimage.0).into_inner()));
 930                                         pending_events.push(
 931                                                 events::Event::PaymentPathSuccessful {
 932                                                         payment_id,
 933                                                         payment_hash,
 934                                                         path,
 935                                                 }
 936                                         );
 937                                 }
 938                         }
 939                 } else {
 940                         log_trace!(logger, "Received duplicative fulfill for HTLC with payment_preimage {}", log_bytes!(payment_preimage.0));
 941                 }
 942         }
 943
 944         pub(super) fn finalize_claims(&self, sources: Vec<HTLCSource>, pending_events: &Mutex<Vec<events::Event>>) {
 945                 let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 946                 let mut pending_events = pending_events.lock().unwrap();
 947                 for source in sources {
 948                         if let HTLCSource::OutboundRoute { session_priv, payment_id, path, .. } = source {
 949                                 let mut session_priv_bytes = [0; 32];
 950                                 session_priv_bytes.copy_from_slice(&session_priv[..]);
 951                                 if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(payment_id) {
 952                                         assert!(payment.get().is_fulfilled());
 953                                         if payment.get_mut().remove(&session_priv_bytes, None) {
 954                                                 pending_events.push(
 955                                                         events::Event::PaymentPathSuccessful {
 956                                                                 payment_id,
 957                                                                 payment_hash: payment.get().payment_hash(),
 958                                                                 path,
 959                                                         }
 960                                                 );
 961                                         }
 962                                 }
 963                         }
 964                 }
 965         }
 966
 967         pub(super) fn remove_stale_resolved_payments(&self, pending_events: &Mutex<Vec<events::Event>>) {
 968                 // If an outbound payment was completed, and no pending HTLCs remain, we should remove it
 969                 // from the map. However, if we did that immediately when the last payment HTLC is claimed,
 970                 // this could race the user making a duplicate send_payment call and our idempotency
 971                 // guarantees would be violated. Instead, we wait a few timer ticks to do the actual
 972                 // removal. This should be more than sufficient to ensure the idempotency of any
 973                 // `send_payment` calls that were made at the same time the `PaymentSent` event was being
 974                 // processed.
 975                 let mut pending_outbound_payments = self.pending_outbound_payments.lock().unwrap();
 976                 let pending_events = pending_events.lock().unwrap();
 977                 pending_outbound_payments.retain(|payment_id, payment| {
 978                         if let PendingOutboundPayment::Fulfilled { session_privs, timer_ticks_without_htlcs, .. } = payment {
 979                                 let mut no_remaining_entries = session_privs.is_empty();
 980                                 if no_remaining_entries {
 981                                         for ev in pending_events.iter() {
 982                                                 match ev {
 983                                                         events::Event::PaymentSent { payment_id: Some(ev_payment_id), .. } |
 984                                                                 events::Event::PaymentPathSuccessful { payment_id: ev_payment_id, .. } |
 985                                                                 events::Event::PaymentPathFailed { payment_id: Some(ev_payment_id), .. } => {
 986                                                                         if payment_id == ev_payment_id {
 987                                                                                 no_remaining_entries = false;
 988                                                                                 break;
 989                                                                         }
 990                                                                 },
 991                                                         _ => {},
 992                                                 }
 993                                         }
 994                                 }
 995                                 if no_remaining_entries {
 996                                         *timer_ticks_without_htlcs += 1;
 997                                         *timer_ticks_without_htlcs <= IDEMPOTENCY_TIMEOUT_TICKS
 998                                 } else {
 999                                         *timer_ticks_without_htlcs = 0;
1000                                         true
1001                                 }
1002                         } else { true }
1003                 });
1004         }
1005
1006         pub(super) fn fail_htlc<L: Deref>(
1007                 &self, source: &HTLCSource, payment_hash: &PaymentHash, onion_error: &HTLCFailReason,
1008                 path: &Vec<RouteHop>, session_priv: &SecretKey, payment_id: &PaymentId,
1009                 payment_params: &Option<PaymentParameters>, probing_cookie_secret: [u8; 32],
1010                 secp_ctx: &Secp256k1<secp256k1::All>, pending_events: &Mutex<Vec<events::Event>>, logger: &L
1011         ) where L::Target: Logger {
1012                 #[cfg(test)]
1013                 let (network_update, short_channel_id, payment_retryable, onion_error_code, onion_error_data) = onion_error.decode_onion_failure(secp_ctx, logger, &source);
1014                 #[cfg(not(test))]
1015                 let (network_update, short_channel_id, payment_retryable, _, _) = onion_error.decode_onion_failure(secp_ctx, logger, &source);
1016
1017                 let payment_is_probe = payment_is_probe(payment_hash, &payment_id, probing_cookie_secret);
1018                 let mut session_priv_bytes = [0; 32];
1019                 session_priv_bytes.copy_from_slice(&session_priv[..]);
1020                 let mut outbounds = self.pending_outbound_payments.lock().unwrap();
1021                 let mut all_paths_failed = false;
1022                 let mut full_failure_ev = None;
1023                 let mut pending_retry_ev = None;
1024                 let mut retry = None;
1025                 let attempts_remaining = if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(*payment_id) {
1026                         if !payment.get_mut().remove(&session_priv_bytes, Some(&path)) {
1027                                 log_trace!(logger, "Received duplicative fail for HTLC with payment_hash {}", log_bytes!(payment_hash.0));
1028                                 return
1029                         }
1030                         if payment.get().is_fulfilled() {
1031                                 log_trace!(logger, "Received failure of HTLC with payment_hash {} after payment completion", log_bytes!(payment_hash.0));
1032                                 return
1033                         }
1034                         let mut is_retryable_now = payment.get().is_auto_retryable_now();
1035                         if let Some(scid) = short_channel_id {
1036                                 payment.get_mut().insert_previously_failed_scid(scid);
1037                         }
1038
1039                         // We want to move towards only using the `PaymentParameters` in the outbound payments
1040                         // map. However, for backwards-compatibility, we still need to support passing the
1041                         // `PaymentParameters` data that was shoved in the HTLC (and given to us via
1042                         // `payment_params`) back to the user.
1043                         let path_last_hop = path.last().expect("Outbound payments must have had a valid path");
1044                         if let Some(params) = payment.get_mut().payment_parameters() {
1045                                 if params.final_cltv_expiry_delta.is_none() {
1046                                         // This should be rare, but a user could provide None for the payment data, and
1047                                         // we need it when we go to retry the payment, so fill it in.
1048                                         params.final_cltv_expiry_delta = Some(path_last_hop.cltv_expiry_delta);
1049                                 }
1050                                 retry = Some(RouteParameters {
1051                                         payment_params: params.clone(),
1052                                         final_value_msat: path_last_hop.fee_msat,
1053                                         final_cltv_expiry_delta: params.final_cltv_expiry_delta.unwrap(),
1054                                 });
1055                         } else if let Some(params) = payment_params {
1056                                 retry = Some(RouteParameters {
1057                                         payment_params: params.clone(),
1058                                         final_value_msat: path_last_hop.fee_msat,
1059                                         final_cltv_expiry_delta:
1060                                                 if let Some(delta) = params.final_cltv_expiry_delta { delta }
1061                                                 else { path_last_hop.cltv_expiry_delta },
1062                                 });
1063                         }
1064
1065                         if !payment_is_probe && (!is_retryable_now || !payment_retryable || retry.is_none()) {
1066                                 let _ = payment.get_mut().mark_abandoned(); // we'll only Err if it's a legacy payment
1067                                 is_retryable_now = false;
1068                         }
1069                         if payment.get().remaining_parts() == 0 {
1070                                 all_paths_failed = true;
1071                                 if payment.get().abandoned() {
1072                                         full_failure_ev = Some(events::Event::PaymentFailed {
1073                                                 payment_id: *payment_id,
1074                                                 payment_hash: payment.get().payment_hash().expect("PendingOutboundPayments::RetriesExceeded always has a payment hash set"),
1075                                         });
1076                                         payment.remove();
1077                                 }
1078                         }
1079                         is_retryable_now
1080                 } else {
1081                         log_trace!(logger, "Received duplicative fail for HTLC with payment_hash {}", log_bytes!(payment_hash.0));
1082                         return
1083                 };
1084                 core::mem::drop(outbounds);
1085                 log_trace!(logger, "Failing outbound payment HTLC with payment_hash {}", log_bytes!(payment_hash.0));
1086
1087                 let path_failure = {
1088                         if payment_is_probe {
1089                                 if !payment_retryable {
1090                                         events::Event::ProbeSuccessful {
1091                                                 payment_id: *payment_id,
1092                                                 payment_hash: payment_hash.clone(),
1093                                                 path: path.clone(),
1094                                         }
1095                                 } else {
1096                                         events::Event::ProbeFailed {
1097                                                 payment_id: *payment_id,
1098                                                 payment_hash: payment_hash.clone(),
1099                                                 path: path.clone(),
1100                                                 short_channel_id,
1101                                         }
1102                                 }
1103                         } else {
1104                                 // TODO: If we decided to blame ourselves (or one of our channels) in
1105                                 // process_onion_failure we should close that channel as it implies our
1106                                 // next-hop is needlessly blaming us!
1107                                 if let Some(scid) = short_channel_id {
1108                                         retry.as_mut().map(|r| r.payment_params.previously_failed_channels.push(scid));
1109                                 }
1110                                 // If we miss abandoning the payment above, we *must* generate an event here or else the
1111                                 // payment will sit in our outbounds forever.
1112                                 if attempts_remaining {
1113                                         debug_assert!(full_failure_ev.is_none());
1114                                         pending_retry_ev = Some(events::Event::PendingHTLCsForwardable {
1115                                                 time_forwardable: Duration::from_millis(MIN_HTLC_RELAY_HOLDING_CELL_MILLIS),
1116                                         });
1117                                 }
1118                                 events::Event::PaymentPathFailed {
1119                                         payment_id: Some(*payment_id),
1120                                         payment_hash: payment_hash.clone(),
1121                                         payment_failed_permanently: !payment_retryable,
1122                                         network_update,
1123                                         all_paths_failed,
1124                                         path: path.clone(),
1125                                         short_channel_id,
1126                                         retry,
1127                                         #[cfg(test)]
1128                                         error_code: onion_error_code,
1129                                         #[cfg(test)]
1130                                         error_data: onion_error_data
1131                                 }
1132                         }
1133                 };
1134                 let mut pending_events = pending_events.lock().unwrap();
1135                 pending_events.push(path_failure);
1136                 if let Some(ev) = full_failure_ev { pending_events.push(ev); }
1137                 if let Some(ev) = pending_retry_ev { pending_events.push(ev); }
1138         }
1139
1140         pub(super) fn abandon_payment(
1141                 &self, payment_id: PaymentId, pending_events: &Mutex<Vec<events::Event>>
1142         ) {
1143                 let mut outbounds = self.pending_outbound_payments.lock().unwrap();
1144                 if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(payment_id) {
1145                         if let Ok(()) = payment.get_mut().mark_abandoned() {
1146                                 if payment.get().remaining_parts() == 0 {
1147                                         pending_events.lock().unwrap().push(events::Event::PaymentFailed {
1148                                                 payment_id,
1149                                                 payment_hash: payment.get().payment_hash().expect("PendingOutboundPayments::RetriesExceeded always has a payment hash set"),
1150                                         });
1151                                         payment.remove();
1152                                 }
1153                         }
1154                 }
1155         }
1156
1157         #[cfg(test)]
1158         pub fn has_pending_payments(&self) -> bool {
1159                 !self.pending_outbound_payments.lock().unwrap().is_empty()
1160         }
1161
1162         #[cfg(test)]
1163         pub fn clear_pending_payments(&self) {
1164                 self.pending_outbound_payments.lock().unwrap().clear()
1165         }
1166 }
1167
1168 /// Returns whether a payment with the given [`PaymentHash`] and [`PaymentId`] is, in fact, a
1169 /// payment probe.
1170 pub(super) fn payment_is_probe(payment_hash: &PaymentHash, payment_id: &PaymentId,
1171         probing_cookie_secret: [u8; 32]) -> bool
1172 {
1173         let target_payment_hash = probing_cookie_from_id(payment_id, probing_cookie_secret);
1174         target_payment_hash == *payment_hash
1175 }
1176
1177 /// Returns the 'probing cookie' for the given [`PaymentId`].
1178 fn probing_cookie_from_id(payment_id: &PaymentId, probing_cookie_secret: [u8; 32]) -> PaymentHash {
1179         let mut preimage = [0u8; 64];
1180         preimage[..32].copy_from_slice(&probing_cookie_secret);
1181         preimage[32..].copy_from_slice(&payment_id.0);
1182         PaymentHash(Sha256::hash(&preimage).into_inner())
1183 }
1184
1185 impl_writeable_tlv_based_enum_upgradable!(PendingOutboundPayment,
1186         (0, Legacy) => {
1187                 (0, session_privs, required),
1188         },
1189         (1, Fulfilled) => {
1190                 (0, session_privs, required),
1191                 (1, payment_hash, option),
1192                 (3, timer_ticks_without_htlcs, (default_value, 0)),
1193         },
1194         (2, Retryable) => {
1195                 (0, session_privs, required),
1196                 (1, pending_fee_msat, option),
1197                 (2, payment_hash, required),
1198                 (3, payment_params, option),
1199                 (4, payment_secret, option),
1200                 (5, keysend_preimage, option),
1201                 (6, total_msat, required),
1202                 (8, pending_amt_msat, required),
1203                 (10, starting_block_height, required),
1204                 (not_written, retry_strategy, (static_value, None)),
1205                 (not_written, attempts, (static_value, PaymentAttempts::new())),
1206         },
1207         (3, Abandoned) => {
1208                 (0, session_privs, required),
1209                 (2, payment_hash, required),
1210         },
1211 );
1212
1213 #[cfg(test)]
1214 mod tests {
1215         use bitcoin::blockdata::constants::genesis_block;
1216         use bitcoin::network::constants::Network;
1217         use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey};
1218
1219         use crate::ln::PaymentHash;
1220         use crate::ln::channelmanager::{PaymentId, PaymentSendFailure};
1221         use crate::ln::msgs::{ErrorAction, LightningError};
1222         use crate::ln::outbound_payment::{OutboundPayments, Retry};
1223         use crate::routing::gossip::NetworkGraph;
1224         use crate::routing::router::{InFlightHtlcs, PaymentParameters, Route, RouteParameters};
1225         use crate::sync::{Arc, Mutex};
1226         use crate::util::errors::APIError;
1227         use crate::util::test_utils;
1228
1229         #[test]
1230         #[cfg(feature = "std")]
1231         fn fails_paying_after_expiration() {
1232                 do_fails_paying_after_expiration(false);
1233                 do_fails_paying_after_expiration(true);
1234         }
1235         #[cfg(feature = "std")]
1236         fn do_fails_paying_after_expiration(on_retry: bool) {
1237                 let outbound_payments = OutboundPayments::new();
1238                 let logger = test_utils::TestLogger::new();
1239                 let genesis_hash = genesis_block(Network::Testnet).header.block_hash();
1240                 let network_graph = Arc::new(NetworkGraph::new(genesis_hash, &logger));
1241                 let scorer = Mutex::new(test_utils::TestScorer::new());
1242                 let router = test_utils::TestRouter::new(network_graph, &scorer);
1243                 let secp_ctx = Secp256k1::new();
1244                 let keys_manager = test_utils::TestKeysInterface::new(&[0; 32], Network::Testnet);
1245
1246                 let past_expiry_time = std::time::SystemTime::UNIX_EPOCH.elapsed().unwrap().as_secs() - 2;
1247                 let payment_params = PaymentParameters::from_node_id(
1248                                 PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap()),
1249                                 0
1250                         ).with_expiry_time(past_expiry_time);
1251                 let expired_route_params = RouteParameters {
1252                         payment_params,
1253                         final_value_msat: 0,
1254                         final_cltv_expiry_delta: 0,
1255                 };
1256                 let err = if on_retry {
1257                         outbound_payments.pay_internal(
1258                                 PaymentId([0; 32]), None, expired_route_params, &&router, vec![], &|| InFlightHtlcs::new(),
1259                                 &&keys_manager, &&keys_manager, 0, &&logger, &|_, _, _, _, _, _, _, _, _| Ok(())).unwrap_err()
1260                 } else {
1261                         outbound_payments.send_payment(
1262                                 PaymentHash([0; 32]), &None, PaymentId([0; 32]), Retry::Attempts(0), expired_route_params,
1263                                 &&router, vec![], || InFlightHtlcs::new(), &&keys_manager, &&keys_manager, 0, &&logger,
1264                                 |_, _, _, _, _, _, _, _, _| Ok(())).unwrap_err()
1265                 };
1266                 if let PaymentSendFailure::ParameterError(APIError::APIMisuseError { err }) = err {
1267                         assert!(err.contains("Invoice expired"));
1268                 } else { panic!("Unexpected error"); }
1269         }
1270
1271         #[test]
1272         fn find_route_error() {
1273                 do_find_route_error(false);
1274                 do_find_route_error(true);
1275         }
1276         fn do_find_route_error(on_retry: bool) {
1277                 let outbound_payments = OutboundPayments::new();
1278                 let logger = test_utils::TestLogger::new();
1279                 let genesis_hash = genesis_block(Network::Testnet).header.block_hash();
1280                 let network_graph = Arc::new(NetworkGraph::new(genesis_hash, &logger));
1281                 let scorer = Mutex::new(test_utils::TestScorer::new());
1282                 let router = test_utils::TestRouter::new(network_graph, &scorer);
1283                 let secp_ctx = Secp256k1::new();
1284                 let keys_manager = test_utils::TestKeysInterface::new(&[0; 32], Network::Testnet);
1285
1286                 let payment_params = PaymentParameters::from_node_id(
1287                         PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap()), 0);
1288                 let route_params = RouteParameters {
1289                         payment_params,
1290                         final_value_msat: 0,
1291                         final_cltv_expiry_delta: 0,
1292                 };
1293                 router.expect_find_route(route_params.clone(),
1294                         Err(LightningError { err: String::new(), action: ErrorAction::IgnoreError }));
1295
1296                 let err = if on_retry {
1297                         outbound_payments.add_new_pending_payment(PaymentHash([0; 32]), None, PaymentId([0; 32]), None,
1298                                 &Route { paths: vec![], payment_params: None }, Some(Retry::Attempts(1)),
1299                                 Some(route_params.payment_params.clone()), &&keys_manager, 0).unwrap();
1300                         outbound_payments.pay_internal(
1301                                 PaymentId([0; 32]), None, route_params, &&router, vec![], &|| InFlightHtlcs::new(),
1302                                 &&keys_manager, &&keys_manager, 0, &&logger, &|_, _, _, _, _, _, _, _, _| Ok(())).unwrap_err()
1303                 } else {
1304                         outbound_payments.send_payment(
1305                                 PaymentHash([0; 32]), &None, PaymentId([0; 32]), Retry::Attempts(0), route_params,
1306                                 &&router, vec![], || InFlightHtlcs::new(), &&keys_manager, &&keys_manager, 0, &&logger,
1307                                 |_, _, _, _, _, _, _, _, _| Ok(())).unwrap_err()
1308                 };
1309                 if let PaymentSendFailure::ParameterError(APIError::APIMisuseError { err }) = err {
1310                         assert!(err.contains("Failed to find a route"));
1311                 } else { panic!("Unexpected error"); }
1312         }
1313 }