_ 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: Option<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_auto_retryable_now(&self) -> bool {
  86                 match self {
  87                         PendingOutboundPayment::Retryable { retry_strategy: Some(strategy), attempts, .. } => {
  88                                 strategy.is_retryable_now(&attempts)
  89                         },
  90                         _ => false,
  91                 }
  92         }
  93         fn is_retryable_now(&self) -> bool {
  94                 match self {
  95                         PendingOutboundPayment::Retryable { retry_strategy: None, .. } => {
  96                                 // We're handling retries manually, we can always retry.
  97                                 true
  98                         },
  99                         PendingOutboundPayment::Retryable { retry_strategy: Some(strategy), attempts, .. } => {
 100                                 strategy.is_retryable_now(&attempts)
 101                         },
 102                         _ => false,
 103                 }
 104         }
 105         pub fn insert_previously_failed_scid(&mut self, scid: u64) {
 106                 if let PendingOutboundPayment::Retryable { route_params: Some(params), .. } = self {
 107                         params.payment_params.previously_failed_channels.push(scid);
 108                 }
 109         }
 110         pub(super) fn is_fulfilled(&self) -> bool {
 111                 match self {
 112                         PendingOutboundPayment::Fulfilled { .. } => true,
 113                         _ => false,
 114                 }
 115         }
 116         pub(super) fn abandoned(&self) -> bool {
 117                 match self {
 118                         PendingOutboundPayment::Abandoned { .. } => true,
 119                         _ => false,
 120                 }
 121         }
 122         fn get_pending_fee_msat(&self) -> Option<u64> {
 123                 match self {
 124                         PendingOutboundPayment::Retryable { pending_fee_msat, .. } => pending_fee_msat.clone(),
 125                         _ => None,
 126                 }
 127         }
 128
 129         fn payment_hash(&self) -> Option<PaymentHash> {
 130                 match self {
 131                         PendingOutboundPayment::Legacy { .. } => None,
 132                         PendingOutboundPayment::Retryable { payment_hash, .. } => Some(*payment_hash),
 133                         PendingOutboundPayment::Fulfilled { payment_hash, .. } => *payment_hash,
 134                         PendingOutboundPayment::Abandoned { payment_hash, .. } => Some(*payment_hash),
 135                 }
 136         }
 137
 138         fn mark_fulfilled(&mut self) {
 139                 let mut session_privs = HashSet::new();
 140                 core::mem::swap(&mut session_privs, match self {
 141                         PendingOutboundPayment::Legacy { session_privs } |
 142                                 PendingOutboundPayment::Retryable { session_privs, .. } |
 143                                 PendingOutboundPayment::Fulfilled { session_privs, .. } |
 144                                 PendingOutboundPayment::Abandoned { session_privs, .. }
 145                         => session_privs,
 146                 });
 147                 let payment_hash = self.payment_hash();
 148                 *self = PendingOutboundPayment::Fulfilled { session_privs, payment_hash, timer_ticks_without_htlcs: 0 };
 149         }
 150
 151         fn mark_abandoned(&mut self) -> Result<(), ()> {
 152                 let mut session_privs = HashSet::new();
 153                 let our_payment_hash;
 154                 core::mem::swap(&mut session_privs, match self {
 155                         PendingOutboundPayment::Legacy { .. } |
 156                                 PendingOutboundPayment::Fulfilled { .. } =>
 157                                 return Err(()),
 158                                 PendingOutboundPayment::Retryable { session_privs, payment_hash, .. } |
 159                                         PendingOutboundPayment::Abandoned { session_privs, payment_hash, .. } => {
 160                                                 our_payment_hash = *payment_hash;
 161                                                 session_privs
 162                                         },
 163                 });
 164                 *self = PendingOutboundPayment::Abandoned { session_privs, payment_hash: our_payment_hash };
 165                 Ok(())
 166         }
 167
 168         /// panics if path is None and !self.is_fulfilled
 169         fn remove(&mut self, session_priv: &[u8; 32], path: Option<&Vec<RouteHop>>) -> bool {
 170                 let remove_res = match self {
 171                         PendingOutboundPayment::Legacy { session_privs } |
 172                                 PendingOutboundPayment::Retryable { session_privs, .. } |
 173                                 PendingOutboundPayment::Fulfilled { session_privs, .. } |
 174                                 PendingOutboundPayment::Abandoned { session_privs, .. } => {
 175                                         session_privs.remove(session_priv)
 176                                 }
 177                 };
 178                 if remove_res {
 179                         if let PendingOutboundPayment::Retryable { ref mut pending_amt_msat, ref mut pending_fee_msat, .. } = self {
 180                                 let path = path.expect("Fulfilling a payment should always come with a path");
 181                                 let path_last_hop = path.last().expect("Outbound payments must have had a valid path");
 182                                 *pending_amt_msat -= path_last_hop.fee_msat;
 183                                 if let Some(fee_msat) = pending_fee_msat.as_mut() {
 184                                         *fee_msat -= path.get_path_fees();
 185                                 }
 186                         }
 187                 }
 188                 remove_res
 189         }
 190
 191         pub(super) fn insert(&mut self, session_priv: [u8; 32], path: &Vec<RouteHop>) -> bool {
 192                 let insert_res = match self {
 193                         PendingOutboundPayment::Legacy { session_privs } |
 194                                 PendingOutboundPayment::Retryable { session_privs, .. } => {
 195                                         session_privs.insert(session_priv)
 196                                 }
 197                         PendingOutboundPayment::Fulfilled { .. } => false,
 198                         PendingOutboundPayment::Abandoned { .. } => false,
 199                 };
 200                 if insert_res {
 201                         if let PendingOutboundPayment::Retryable { ref mut pending_amt_msat, ref mut pending_fee_msat, .. } = self {
 202                                 let path_last_hop = path.last().expect("Outbound payments must have had a valid path");
 203                                 *pending_amt_msat += path_last_hop.fee_msat;
 204                                 if let Some(fee_msat) = pending_fee_msat.as_mut() {
 205                                         *fee_msat += path.get_path_fees();
 206                                 }
 207                         }
 208                 }
 209                 insert_res
 210         }
 211
 212         pub(super) fn remaining_parts(&self) -> usize {
 213                 match self {
 214                         PendingOutboundPayment::Legacy { session_privs } |
 215                                 PendingOutboundPayment::Retryable { session_privs, .. } |
 216                                 PendingOutboundPayment::Fulfilled { session_privs, .. } |
 217                                 PendingOutboundPayment::Abandoned { session_privs, .. } => {
 218                                         session_privs.len()
 219                                 }
 220                 }
 221         }
 222 }
 223
 224 /// Strategies available to retry payment path failures.
 225 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
 226 pub enum Retry {
 227         /// Max number of attempts to retry payment.
 228         ///
 229         /// Each attempt may be multiple HTLCs along multiple paths if the router decides to split up a
 230         /// retry, and may retry multiple failed HTLCs at once if they failed around the same time and
 231         /// were retried along a route from a single call to [`Router::find_route`].
 232         Attempts(usize),
 233         #[cfg(not(feature = "no-std"))]
 234         /// Time elapsed before abandoning retries for a payment.
 235         Timeout(core::time::Duration),
 236 }
 237
 238 impl Retry {
 239         pub(crate) fn is_retryable_now(&self, attempts: &PaymentAttempts) -> bool {
 240                 match (self, attempts) {
 241                         (Retry::Attempts(max_retry_count), PaymentAttempts { count, .. }) => {
 242                                 max_retry_count > count
 243                         },
 244                         #[cfg(all(not(feature = "no-std"), not(test)))]
 245                         (Retry::Timeout(max_duration), PaymentAttempts { first_attempted_at, .. }) =>
 246                                 *max_duration >= std::time::Instant::now().duration_since(*first_attempted_at),
 247                         #[cfg(all(not(feature = "no-std"), test))]
 248                         (Retry::Timeout(max_duration), PaymentAttempts { first_attempted_at, .. }) =>
 249                                 *max_duration >= SinceEpoch::now().duration_since(*first_attempted_at),
 250                 }
 251         }
 252 }
 253
 254 #[cfg(feature = "std")]
 255 pub(super) fn has_expired(route_params: &RouteParameters) -> bool {
 256         if let Some(expiry_time) = route_params.payment_params.expiry_time {
 257                 if let Ok(elapsed) = std::time::SystemTime::UNIX_EPOCH.elapsed() {
 258                         return elapsed > core::time::Duration::from_secs(expiry_time)
 259                 }
 260         }
 261         false
 262 }
 263
 264 pub(crate) type PaymentAttempts = PaymentAttemptsUsingTime<ConfiguredTime>;
 265
 266 /// Storing minimal payment attempts information required for determining if a outbound payment can
 267 /// be retried.
 268 pub(crate) struct PaymentAttemptsUsingTime<T: Time> {
 269         /// This count will be incremented only after the result of the attempt is known. When it's 0,
 270         /// it means the result of the first attempt is not known yet.
 271         pub(crate) count: usize,
 272         /// This field is only used when retry is `Retry::Timeout` which is only build with feature std
 273         first_attempted_at: T
 274 }
 275
 276 #[cfg(not(any(feature = "no-std", test)))]
 277 type ConfiguredTime = std::time::Instant;
 278 #[cfg(feature = "no-std")]
 279 type ConfiguredTime = crate::util::time::Eternity;
 280 #[cfg(all(not(feature = "no-std"), test))]
 281 type ConfiguredTime = SinceEpoch;
 282
 283 impl<T: Time> PaymentAttemptsUsingTime<T> {
 284         pub(crate) fn new() -> Self {
 285                 PaymentAttemptsUsingTime {
 286                         count: 0,
 287                         first_attempted_at: T::now()
 288                 }
 289         }
 290 }
 291
 292 impl<T: Time> Display for PaymentAttemptsUsingTime<T> {
 293         fn fmt(&self, f: &mut Formatter) -> Result<(), fmt::Error> {
 294                 #[cfg(feature = "no-std")]
 295                 return write!(f, "attempts: {}", self.count);
 296                 #[cfg(not(feature = "no-std"))]
 297                 return write!(
 298                         f,
 299                         "attempts: {}, duration: {}s",
 300                         self.count,
 301                         T::now().duration_since(self.first_attempted_at).as_secs()
 302                 );
 303         }
 304 }
 305
 306 /// If a payment fails to send, it can be in one of several states. This enum is returned as the
 307 /// Err() type describing which state the payment is in, see the description of individual enum
 308 /// states for more.
 309 #[derive(Clone, Debug)]
 310 pub enum PaymentSendFailure {
 311         /// A parameter which was passed to send_payment was invalid, preventing us from attempting to
 312         /// send the payment at all.
 313         ///
 314         /// You can freely resend the payment in full (with the parameter error fixed).
 315         ///
 316         /// Because the payment failed outright, no payment tracking is done, you do not need to call
 317         /// [`ChannelManager::abandon_payment`] and [`ChannelManager::retry_payment`] will *not* work
 318         /// for this payment.
 319         ///
 320         /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
 321         /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
 322         ParameterError(APIError),
 323         /// A parameter in a single path which was passed to send_payment was invalid, preventing us
 324         /// from attempting to send the payment at all.
 325         ///
 326         /// You can freely resend the payment in full (with the parameter error fixed).
 327         ///
 328         /// The results here are ordered the same as the paths in the route object which was passed to
 329         /// send_payment.
 330         ///
 331         /// Because the payment failed outright, no payment tracking is done, you do not need to call
 332         /// [`ChannelManager::abandon_payment`] and [`ChannelManager::retry_payment`] will *not* work
 333         /// for this payment.
 334         ///
 335         /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
 336         /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
 337         PathParameterError(Vec<Result<(), APIError>>),
 338         /// All paths which were attempted failed to send, with no channel state change taking place.
 339         /// You can freely resend the payment in full (though you probably want to do so over different
 340         /// paths than the ones selected).
 341         ///
 342         /// Because the payment failed outright, no payment tracking is done, you do not need to call
 343         /// [`ChannelManager::abandon_payment`] and [`ChannelManager::retry_payment`] will *not* work
 344         /// for this payment.
 345         ///
 346         /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
 347         /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
 348         AllFailedResendSafe(Vec<APIError>),
 349         /// Indicates that a payment for the provided [`PaymentId`] is already in-flight and has not
 350         /// yet completed (i.e. generated an [`Event::PaymentSent`]) or been abandoned (via
 351         /// [`ChannelManager::abandon_payment`]).
 352         ///
 353         /// [`PaymentId`]: crate::ln::channelmanager::PaymentId
 354         /// [`Event::PaymentSent`]: crate::util::events::Event::PaymentSent
 355         /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
 356         DuplicatePayment,
 357         /// Some paths which were attempted failed to send, though possibly not all. At least some
 358         /// paths have irrevocably committed to the HTLC and retrying the payment in full would result
 359         /// in over-/re-payment.
 360         ///
 361         /// The results here are ordered the same as the paths in the route object which was passed to
 362         /// send_payment, and any `Err`s which are not [`APIError::MonitorUpdateInProgress`] can be
 363         /// safely retried via [`ChannelManager::retry_payment`].
 364         ///
 365         /// Any entries which contain `Err(APIError::MonitorUpdateInprogress)` or `Ok(())` MUST NOT be
 366         /// retried as they will result in over-/re-payment. These HTLCs all either successfully sent
 367         /// (in the case of `Ok(())`) or will send once a [`MonitorEvent::Completed`] is provided for
 368         /// the next-hop channel with the latest update_id.
 369         ///
 370         /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
 371         /// [`MonitorEvent::Completed`]: crate::chain::channelmonitor::MonitorEvent::Completed
 372         PartialFailure {
 373                 /// The errors themselves, in the same order as the route hops.
 374                 results: Vec<Result<(), APIError>>,
 375                 /// If some paths failed without irrevocably committing to the new HTLC(s), this will
 376                 /// contain a [`RouteParameters`] object which can be used to calculate a new route that
 377                 /// will pay all remaining unpaid balance.
 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, F, 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>, inflight_htlcs: InFlightHtlcs, entropy_source: &ES,
 399                 node_signer: &NS, best_block_height: u32, logger: &L, send_payment_along_path: F,
 400         ) -> Result<(), PaymentSendFailure>
 401         where
 402                 R::Target: Router,
 403                 ES::Target: EntropySource,
 404                 NS::Target: NodeSigner,
 405                 L::Target: Logger,
 406                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 407                          u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>,
 408         {
 409                 self.pay_internal(payment_id, Some((payment_hash, payment_secret, retry_strategy)),
 410                         route_params, router, first_hops, inflight_htlcs, entropy_source, node_signer,
 411                         best_block_height, logger, &send_payment_along_path)
 412                         .map_err(|e| { self.remove_outbound_if_all_failed(payment_id, &e); e })
 413         }
 414
 415         pub(super) fn send_payment_with_route<ES: Deref, NS: Deref, F>(
 416                 &self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>,
 417                 payment_id: PaymentId, entropy_source: &ES, node_signer: &NS, best_block_height: u32,
 418                 send_payment_along_path: F
 419         ) -> Result<(), PaymentSendFailure>
 420         where
 421                 ES::Target: EntropySource,
 422                 NS::Target: NodeSigner,
 423                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 424                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 425         {
 426                 let onion_session_privs = self.add_new_pending_payment(payment_hash, *payment_secret, payment_id, route, None, None, entropy_source, best_block_height)?;
 427                 self.pay_route_internal(route, payment_hash, payment_secret, None, payment_id, None,
 428                         onion_session_privs, node_signer, best_block_height, &send_payment_along_path)
 429                         .map_err(|e| { self.remove_outbound_if_all_failed(payment_id, &e); e })
 430         }
 431
 432         pub(super) fn send_spontaneous_payment<ES: Deref, NS: Deref, F>(
 433                 &self, route: &Route, payment_preimage: Option<PaymentPreimage>, payment_id: PaymentId,
 434                 entropy_source: &ES, node_signer: &NS, best_block_height: u32, send_payment_along_path: F
 435         ) -> Result<PaymentHash, PaymentSendFailure>
 436         where
 437                 ES::Target: EntropySource,
 438                 NS::Target: NodeSigner,
 439                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 440                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 441         {
 442                 let preimage = match payment_preimage {
 443                         Some(p) => p,
 444                         None => PaymentPreimage(entropy_source.get_secure_random_bytes()),
 445                 };
 446                 let payment_hash = PaymentHash(Sha256::hash(&preimage.0).into_inner());
 447                 let onion_session_privs = self.add_new_pending_payment(payment_hash, None, payment_id, &route, None, None, entropy_source, best_block_height)?;
 448
 449                 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) {
 450                         Ok(()) => Ok(payment_hash),
 451                         Err(e) => {
 452                                 self.remove_outbound_if_all_failed(payment_id, &e);
 453                                 Err(e)
 454                         }
 455                 }
 456         }
 457
 458         pub(super) fn check_retry_payments<R: Deref, ES: Deref, NS: Deref, SP, IH, FH, L: Deref>(
 459                 &self, router: &R, first_hops: FH, inflight_htlcs: IH, entropy_source: &ES, node_signer: &NS,
 460                 best_block_height: u32, logger: &L, send_payment_along_path: SP,
 461         )
 462         where
 463                 R::Target: Router,
 464                 ES::Target: EntropySource,
 465                 NS::Target: NodeSigner,
 466                 SP: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 467                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>,
 468                 IH: Fn() -> InFlightHtlcs,
 469                 FH: Fn() -> Vec<ChannelDetails>,
 470                 L::Target: Logger,
 471         {
 472                 loop {
 473                         let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 474                         let mut retry_id_route_params = None;
 475                         for (pmt_id, pmt) in outbounds.iter_mut() {
 476                                 if pmt.is_auto_retryable_now() {
 477                                         if let PendingOutboundPayment::Retryable { pending_amt_msat, total_msat, route_params: Some(params), .. } = pmt {
 478                                                 if pending_amt_msat < total_msat {
 479                                                         retry_id_route_params = Some((*pmt_id, params.clone()));
 480                                                         break
 481                                                 }
 482                                         }
 483                                 }
 484                         }
 485                         if let Some((payment_id, route_params)) = retry_id_route_params {
 486                                 core::mem::drop(outbounds);
 487                                 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) {
 488                                         log_info!(logger, "Errored retrying payment: {:?}", e);
 489                                 }
 490                         } else { break }
 491                 }
 492         }
 493
 494         fn pay_internal<R: Deref, NS: Deref, ES: Deref, F, L: Deref>(
 495                 &self, payment_id: PaymentId,
 496                 initial_send_info: Option<(PaymentHash, &Option<PaymentSecret>, Retry)>,
 497                 route_params: RouteParameters, router: &R, first_hops: Vec<ChannelDetails>,
 498                 inflight_htlcs: InFlightHtlcs, entropy_source: &ES, node_signer: &NS, best_block_height: u32,
 499                 logger: &L, send_payment_along_path: &F,
 500         ) -> Result<(), PaymentSendFailure>
 501         where
 502                 R::Target: Router,
 503                 ES::Target: EntropySource,
 504                 NS::Target: NodeSigner,
 505                 L::Target: Logger,
 506                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 507                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 508         {
 509                 #[cfg(feature = "std")] {
 510                         if has_expired(&route_params) {
 511                                 return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 512                                         err: format!("Invoice expired for payment id {}", log_bytes!(payment_id.0)),
 513                                 }))
 514                         }
 515                 }
 516
 517                 let route = router.find_route(
 518                         &node_signer.get_node_id(Recipient::Node).unwrap(), &route_params,
 519                         Some(&first_hops.iter().collect::<Vec<_>>()), &inflight_htlcs
 520                 ).map_err(|e| PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 521                         err: format!("Failed to find a route for payment {}: {:?}", log_bytes!(payment_id.0), e), // TODO: add APIError::RouteNotFound
 522                 }))?;
 523
 524                 let res = if let Some((payment_hash, payment_secret, retry_strategy)) = initial_send_info {
 525                         let onion_session_privs = self.add_new_pending_payment(payment_hash, *payment_secret, payment_id, &route, Some(retry_strategy), Some(route_params.clone()), entropy_source, best_block_height)?;
 526                         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)
 527                 } else {
 528                         self.retry_payment_with_route(&route, payment_id, entropy_source, node_signer, best_block_height, send_payment_along_path)
 529                 };
 530                 match res {
 531                         Err(PaymentSendFailure::AllFailedResendSafe(_)) => {
 532                                 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);
 533                                 log_info!(logger, "Result retrying payment id {}: {:?}", log_bytes!(payment_id.0), retry_res);
 534                                 if let Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError { err })) = &retry_res {
 535                                         if err.starts_with("Retries exhausted ") { return res; }
 536                                 }
 537                                 retry_res
 538                         },
 539                         Err(PaymentSendFailure::PartialFailure { failed_paths_retry: Some(retry), .. }) => {
 540                                 // Some paths were sent, even if we failed to send the full MPP value our recipient may
 541                                 // misbehave and claim the funds, at which point we have to consider the payment sent, so
 542                                 // return `Ok()` here, ignoring any retry errors.
 543                                 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);
 544                                 log_info!(logger, "Result retrying payment id {}: {:?}", log_bytes!(payment_id.0), retry_res);
 545                                 Ok(())
 546                         },
 547                         Err(PaymentSendFailure::PartialFailure { failed_paths_retry: None, .. }) => {
 548                                 // This may happen if we send a payment and some paths fail, but only due to a temporary
 549                                 // monitor failure or the like, implying they're really in-flight, but we haven't sent the
 550                                 // initial HTLC-Add messages yet.
 551                                 Ok(())
 552                         },
 553                         res => res,
 554                 }
 555         }
 556
 557         pub(super) fn retry_payment_with_route<ES: Deref, NS: Deref, F>(
 558                 &self, route: &Route, payment_id: PaymentId, entropy_source: &ES, node_signer: &NS, best_block_height: u32,
 559                 send_payment_along_path: F
 560         ) -> Result<(), PaymentSendFailure>
 561         where
 562                 ES::Target: EntropySource,
 563                 NS::Target: NodeSigner,
 564                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 565                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 566         {
 567                 const RETRY_OVERFLOW_PERCENTAGE: u64 = 10;
 568                 for path in route.paths.iter() {
 569                         if path.len() == 0 {
 570                                 return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 571                                         err: "length-0 path in route".to_string()
 572                                 }))
 573                         }
 574                 }
 575
 576                 let mut onion_session_privs = Vec::with_capacity(route.paths.len());
 577                 for _ in 0..route.paths.len() {
 578                         onion_session_privs.push(entropy_source.get_secure_random_bytes());
 579                 }
 580
 581                 let (total_msat, payment_hash, payment_secret) = {
 582                         let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 583                         match outbounds.get_mut(&payment_id) {
 584                                 Some(payment) => {
 585                                         let res = match payment {
 586                                                 PendingOutboundPayment::Retryable {
 587                                                         total_msat, payment_hash, payment_secret, pending_amt_msat, ..
 588                                                 } => {
 589                                                         let retry_amt_msat: u64 = route.paths.iter().map(|path| path.last().unwrap().fee_msat).sum();
 590                                                         if retry_amt_msat + *pending_amt_msat > *total_msat * (100 + RETRY_OVERFLOW_PERCENTAGE) / 100 {
 591                                                                 return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 592                                                                         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()
 593                                                                 }))
 594                                                         }
 595                                                         (*total_msat, *payment_hash, *payment_secret)
 596                                                 },
 597                                                 PendingOutboundPayment::Legacy { .. } => {
 598                                                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 599                                                                 err: "Unable to retry payments that were initially sent on LDK versions prior to 0.0.102".to_string()
 600                                                         }))
 601                                                 },
 602                                                 PendingOutboundPayment::Fulfilled { .. } => {
 603                                                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 604                                                                 err: "Payment already completed".to_owned()
 605                                                         }));
 606                                                 },
 607                                                 PendingOutboundPayment::Abandoned { .. } => {
 608                                                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 609                                                                 err: "Payment already abandoned (with some HTLCs still pending)".to_owned()
 610                                                         }));
 611                                                 },
 612                                         };
 613                                         if !payment.is_retryable_now() {
 614                                                 return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 615                                                         err: format!("Retries exhausted for payment id {}", log_bytes!(payment_id.0)),
 616                                                 }))
 617                                         }
 618                                         payment.increment_attempts();
 619                                         for (path, session_priv_bytes) in route.paths.iter().zip(onion_session_privs.iter()) {
 620                                                 assert!(payment.insert(*session_priv_bytes, path));
 621                                         }
 622                                         res
 623                                 },
 624                                 None =>
 625                                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 626                                                 err: format!("Payment with ID {} not found", log_bytes!(payment_id.0)),
 627                                         })),
 628                         }
 629                 };
 630                 self.pay_route_internal(route, payment_hash, &payment_secret, None, payment_id, Some(total_msat), onion_session_privs, node_signer, best_block_height, &send_payment_along_path)
 631         }
 632
 633         pub(super) fn send_probe<ES: Deref, NS: Deref, F>(
 634                 &self, hops: Vec<RouteHop>, probing_cookie_secret: [u8; 32], entropy_source: &ES,
 635                 node_signer: &NS, best_block_height: u32, send_payment_along_path: F
 636         ) -> Result<(PaymentHash, PaymentId), PaymentSendFailure>
 637         where
 638                 ES::Target: EntropySource,
 639                 NS::Target: NodeSigner,
 640                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 641                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 642         {
 643                 let payment_id = PaymentId(entropy_source.get_secure_random_bytes());
 644
 645                 let payment_hash = probing_cookie_from_id(&payment_id, probing_cookie_secret);
 646
 647                 if hops.len() < 2 {
 648                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 649                                 err: "No need probing a path with less than two hops".to_string()
 650                         }))
 651                 }
 652
 653                 let route = Route { paths: vec![hops], payment_params: None };
 654                 let onion_session_privs = self.add_new_pending_payment(payment_hash, None, payment_id, &route, None, None, entropy_source, best_block_height)?;
 655
 656                 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) {
 657                         Ok(()) => Ok((payment_hash, payment_id)),
 658                         Err(e) => {
 659                                 self.remove_outbound_if_all_failed(payment_id, &e);
 660                                 Err(e)
 661                         }
 662                 }
 663         }
 664
 665         #[cfg(test)]
 666         pub(super) fn test_add_new_pending_payment<ES: Deref>(
 667                 &self, payment_hash: PaymentHash, payment_secret: Option<PaymentSecret>, payment_id: PaymentId,
 668                 route: &Route, retry_strategy: Option<Retry>, entropy_source: &ES, best_block_height: u32
 669         ) -> Result<Vec<[u8; 32]>, PaymentSendFailure> where ES::Target: EntropySource {
 670                 self.add_new_pending_payment(payment_hash, payment_secret, payment_id, route, retry_strategy, None, entropy_source, best_block_height)
 671         }
 672
 673         pub(super) fn add_new_pending_payment<ES: Deref>(
 674                 &self, payment_hash: PaymentHash, payment_secret: Option<PaymentSecret>, payment_id: PaymentId,
 675                 route: &Route, retry_strategy: Option<Retry>, route_params: Option<RouteParameters>,
 676                 entropy_source: &ES, best_block_height: u32
 677         ) -> Result<Vec<[u8; 32]>, PaymentSendFailure> where ES::Target: EntropySource {
 678                 let mut onion_session_privs = Vec::with_capacity(route.paths.len());
 679                 for _ in 0..route.paths.len() {
 680                         onion_session_privs.push(entropy_source.get_secure_random_bytes());
 681                 }
 682
 683                 let mut pending_outbounds = self.pending_outbound_payments.lock().unwrap();
 684                 match pending_outbounds.entry(payment_id) {
 685                         hash_map::Entry::Occupied(_) => Err(PaymentSendFailure::DuplicatePayment),
 686                         hash_map::Entry::Vacant(entry) => {
 687                                 let payment = entry.insert(PendingOutboundPayment::Retryable {
 688                                         retry_strategy,
 689                                         attempts: PaymentAttempts::new(),
 690                                         route_params,
 691                                         session_privs: HashSet::new(),
 692                                         pending_amt_msat: 0,
 693                                         pending_fee_msat: Some(0),
 694                                         payment_hash,
 695                                         payment_secret,
 696                                         starting_block_height: best_block_height,
 697                                         total_msat: route.get_total_amount(),
 698                                 });
 699
 700                                 for (path, session_priv_bytes) in route.paths.iter().zip(onion_session_privs.iter()) {
 701                                         assert!(payment.insert(*session_priv_bytes, path));
 702                                 }
 703
 704                                 Ok(onion_session_privs)
 705                         },
 706                 }
 707         }
 708
 709         fn pay_route_internal<NS: Deref, F>(
 710                 &self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>,
 711                 keysend_preimage: Option<PaymentPreimage>, payment_id: PaymentId, recv_value_msat: Option<u64>,
 712                 onion_session_privs: Vec<[u8; 32]>, node_signer: &NS, best_block_height: u32,
 713                 send_payment_along_path: &F
 714         ) -> Result<(), PaymentSendFailure>
 715         where
 716                 NS::Target: NodeSigner,
 717                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 718                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 719         {
 720                 if route.paths.len() < 1 {
 721                         return Err(PaymentSendFailure::ParameterError(APIError::InvalidRoute{err: "There must be at least one path to send over"}));
 722                 }
 723                 if payment_secret.is_none() && route.paths.len() > 1 {
 724                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError{err: "Payment secret is required for multi-path payments".to_string()}));
 725                 }
 726                 let mut total_value = 0;
 727                 let our_node_id = node_signer.get_node_id(Recipient::Node).unwrap(); // TODO no unwrap
 728                 let mut path_errs = Vec::with_capacity(route.paths.len());
 729                 'path_check: for path in route.paths.iter() {
 730                         if path.len() < 1 || path.len() > 20 {
 731                                 path_errs.push(Err(APIError::InvalidRoute{err: "Path didn't go anywhere/had bogus size"}));
 732                                 continue 'path_check;
 733                         }
 734                         for (idx, hop) in path.iter().enumerate() {
 735                                 if idx != path.len() - 1 && hop.pubkey == our_node_id {
 736                                         path_errs.push(Err(APIError::InvalidRoute{err: "Path went through us but wasn't a simple rebalance loop to us"}));
 737                                         continue 'path_check;
 738                                 }
 739                         }
 740                         total_value += path.last().unwrap().fee_msat;
 741                         path_errs.push(Ok(()));
 742                 }
 743                 if path_errs.iter().any(|e| e.is_err()) {
 744                         return Err(PaymentSendFailure::PathParameterError(path_errs));
 745                 }
 746                 if let Some(amt_msat) = recv_value_msat {
 747                         debug_assert!(amt_msat >= total_value);
 748                         total_value = amt_msat;
 749                 }
 750
 751                 let cur_height = best_block_height + 1;
 752                 let mut results = Vec::new();
 753                 debug_assert_eq!(route.paths.len(), onion_session_privs.len());
 754                 for (path, session_priv) in route.paths.iter().zip(onion_session_privs.into_iter()) {
 755                         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);
 756                         match path_res {
 757                                 Ok(_) => {},
 758                                 Err(APIError::MonitorUpdateInProgress) => {
 759                                         // While a MonitorUpdateInProgress is an Err(_), the payment is still
 760                                         // considered "in flight" and we shouldn't remove it from the
 761                                         // PendingOutboundPayment set.
 762                                 },
 763                                 Err(_) => {
 764                                         let mut pending_outbounds = self.pending_outbound_payments.lock().unwrap();
 765                                         if let Some(payment) = pending_outbounds.get_mut(&payment_id) {
 766                                                 let removed = payment.remove(&session_priv, Some(path));
 767                                                 debug_assert!(removed, "This can't happen as the payment has an entry for this path added by callers");
 768                                         } else {
 769                                                 debug_assert!(false, "This can't happen as the payment was added by callers");
 770                                                 path_res = Err(APIError::APIMisuseError { err: "Internal error: payment disappeared during processing. Please report this bug!".to_owned() });
 771                                         }
 772                                 }
 773                         }
 774                         results.push(path_res);
 775                 }
 776                 let mut has_ok = false;
 777                 let mut has_err = false;
 778                 let mut pending_amt_unsent = 0;
 779                 let mut max_unsent_cltv_delta = 0;
 780                 for (res, path) in results.iter().zip(route.paths.iter()) {
 781                         if res.is_ok() { has_ok = true; }
 782                         if res.is_err() { has_err = true; }
 783                         if let &Err(APIError::MonitorUpdateInProgress) = res {
 784                                 // MonitorUpdateInProgress is inherently unsafe to retry, so we call it a
 785                                 // PartialFailure.
 786                                 has_err = true;
 787                                 has_ok = true;
 788                         } else if res.is_err() {
 789                                 pending_amt_unsent += path.last().unwrap().fee_msat;
 790                                 max_unsent_cltv_delta = cmp::max(max_unsent_cltv_delta, path.last().unwrap().cltv_expiry_delta);
 791                         }
 792                 }
 793                 if has_err && has_ok {
 794                         Err(PaymentSendFailure::PartialFailure {
 795                                 results,
 796                                 payment_id,
 797                                 failed_paths_retry: if pending_amt_unsent != 0 {
 798                                         if let Some(payment_params) = &route.payment_params {
 799                                                 Some(RouteParameters {
 800                                                         payment_params: payment_params.clone(),
 801                                                         final_value_msat: pending_amt_unsent,
 802                                                         final_cltv_expiry_delta:
 803                                                                 if let Some(delta) = payment_params.final_cltv_expiry_delta { delta }
 804                                                                 else { max_unsent_cltv_delta },
 805                                                 })
 806                                         } else { None }
 807                                 } else { None },
 808                         })
 809                 } else if has_err {
 810                         Err(PaymentSendFailure::AllFailedResendSafe(results.drain(..).map(|r| r.unwrap_err()).collect()))
 811                 } else {
 812                         Ok(())
 813                 }
 814         }
 815
 816         #[cfg(test)]
 817         pub(super) fn test_send_payment_internal<NS: Deref, F>(
 818                 &self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>,
 819                 keysend_preimage: Option<PaymentPreimage>, payment_id: PaymentId, recv_value_msat: Option<u64>,
 820                 onion_session_privs: Vec<[u8; 32]>, node_signer: &NS, best_block_height: u32,
 821                 send_payment_along_path: F
 822         ) -> Result<(), PaymentSendFailure>
 823         where
 824                 NS::Target: NodeSigner,
 825                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 826                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 827         {
 828                 self.pay_route_internal(route, payment_hash, payment_secret, keysend_preimage, payment_id,
 829                         recv_value_msat, onion_session_privs, node_signer, best_block_height,
 830                         &send_payment_along_path)
 831                         .map_err(|e| { self.remove_outbound_if_all_failed(payment_id, &e); e })
 832         }
 833
 834         // If we failed to send any paths, we should remove the new PaymentId from the
 835         // `pending_outbound_payments` map, as the user isn't expected to `abandon_payment`.
 836         fn remove_outbound_if_all_failed(&self, payment_id: PaymentId, err: &PaymentSendFailure) {
 837                 if let &PaymentSendFailure::AllFailedResendSafe(_) = err {
 838                         let removed = self.pending_outbound_payments.lock().unwrap().remove(&payment_id).is_some();
 839                         debug_assert!(removed, "We should always have a pending payment to remove here");
 840                 }
 841         }
 842
 843         pub(super) fn claim_htlc<L: Deref>(
 844                 &self, payment_id: PaymentId, payment_preimage: PaymentPreimage, session_priv: SecretKey,
 845                 path: Vec<RouteHop>, from_onchain: bool, pending_events: &Mutex<Vec<events::Event>>, logger: &L
 846         ) where L::Target: Logger {
 847                 let mut session_priv_bytes = [0; 32];
 848                 session_priv_bytes.copy_from_slice(&session_priv[..]);
 849                 let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 850                 let mut pending_events = pending_events.lock().unwrap();
 851                 if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(payment_id) {
 852                         if !payment.get().is_fulfilled() {
 853                                 let payment_hash = PaymentHash(Sha256::hash(&payment_preimage.0).into_inner());
 854                                 let fee_paid_msat = payment.get().get_pending_fee_msat();
 855                                 pending_events.push(
 856                                         events::Event::PaymentSent {
 857                                                 payment_id: Some(payment_id),
 858                                                 payment_preimage,
 859                                                 payment_hash,
 860                                                 fee_paid_msat,
 861                                         }
 862                                 );
 863                                 payment.get_mut().mark_fulfilled();
 864                         }
 865
 866                         if from_onchain {
 867                                 // We currently immediately remove HTLCs which were fulfilled on-chain.
 868                                 // This could potentially lead to removing a pending payment too early,
 869                                 // with a reorg of one block causing us to re-add the fulfilled payment on
 870                                 // restart.
 871                                 // TODO: We should have a second monitor event that informs us of payments
 872                                 // irrevocably fulfilled.
 873                                 if payment.get_mut().remove(&session_priv_bytes, Some(&path)) {
 874                                         let payment_hash = Some(PaymentHash(Sha256::hash(&payment_preimage.0).into_inner()));
 875                                         pending_events.push(
 876                                                 events::Event::PaymentPathSuccessful {
 877                                                         payment_id,
 878                                                         payment_hash,
 879                                                         path,
 880                                                 }
 881                                         );
 882                                 }
 883                         }
 884                 } else {
 885                         log_trace!(logger, "Received duplicative fulfill for HTLC with payment_preimage {}", log_bytes!(payment_preimage.0));
 886                 }
 887         }
 888
 889         pub(super) fn finalize_claims(&self, sources: Vec<HTLCSource>, pending_events: &Mutex<Vec<events::Event>>) {
 890                 let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 891                 let mut pending_events = pending_events.lock().unwrap();
 892                 for source in sources {
 893                         if let HTLCSource::OutboundRoute { session_priv, payment_id, path, .. } = source {
 894                                 let mut session_priv_bytes = [0; 32];
 895                                 session_priv_bytes.copy_from_slice(&session_priv[..]);
 896                                 if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(payment_id) {
 897                                         assert!(payment.get().is_fulfilled());
 898                                         if payment.get_mut().remove(&session_priv_bytes, None) {
 899                                                 pending_events.push(
 900                                                         events::Event::PaymentPathSuccessful {
 901                                                                 payment_id,
 902                                                                 payment_hash: payment.get().payment_hash(),
 903                                                                 path,
 904                                                         }
 905                                                 );
 906                                         }
 907                                 }
 908                         }
 909                 }
 910         }
 911
 912         pub(super) fn remove_stale_resolved_payments(&self, pending_events: &Mutex<Vec<events::Event>>) {
 913                 // If an outbound payment was completed, and no pending HTLCs remain, we should remove it
 914                 // from the map. However, if we did that immediately when the last payment HTLC is claimed,
 915                 // this could race the user making a duplicate send_payment call and our idempotency
 916                 // guarantees would be violated. Instead, we wait a few timer ticks to do the actual
 917                 // removal. This should be more than sufficient to ensure the idempotency of any
 918                 // `send_payment` calls that were made at the same time the `PaymentSent` event was being
 919                 // processed.
 920                 let mut pending_outbound_payments = self.pending_outbound_payments.lock().unwrap();
 921                 let pending_events = pending_events.lock().unwrap();
 922                 pending_outbound_payments.retain(|payment_id, payment| {
 923                         if let PendingOutboundPayment::Fulfilled { session_privs, timer_ticks_without_htlcs, .. } = payment {
 924                                 let mut no_remaining_entries = session_privs.is_empty();
 925                                 if no_remaining_entries {
 926                                         for ev in pending_events.iter() {
 927                                                 match ev {
 928                                                         events::Event::PaymentSent { payment_id: Some(ev_payment_id), .. } |
 929                                                                 events::Event::PaymentPathSuccessful { payment_id: ev_payment_id, .. } |
 930                                                                 events::Event::PaymentPathFailed { payment_id: Some(ev_payment_id), .. } => {
 931                                                                         if payment_id == ev_payment_id {
 932                                                                                 no_remaining_entries = false;
 933                                                                                 break;
 934                                                                         }
 935                                                                 },
 936                                                         _ => {},
 937                                                 }
 938                                         }
 939                                 }
 940                                 if no_remaining_entries {
 941                                         *timer_ticks_without_htlcs += 1;
 942                                         *timer_ticks_without_htlcs <= IDEMPOTENCY_TIMEOUT_TICKS
 943                                 } else {
 944                                         *timer_ticks_without_htlcs = 0;
 945                                         true
 946                                 }
 947                         } else { true }
 948                 });
 949         }
 950
 951         pub(super) fn fail_htlc<L: Deref>(
 952                 &self, source: &HTLCSource, payment_hash: &PaymentHash, onion_error: &HTLCFailReason,
 953                 path: &Vec<RouteHop>, session_priv: &SecretKey, payment_id: &PaymentId,
 954                 payment_params: &Option<PaymentParameters>, probing_cookie_secret: [u8; 32],
 955                 secp_ctx: &Secp256k1<secp256k1::All>, pending_events: &Mutex<Vec<events::Event>>, logger: &L
 956         ) where L::Target: Logger {
 957                 #[cfg(test)]
 958                 let (network_update, short_channel_id, payment_retryable, onion_error_code, onion_error_data) = onion_error.decode_onion_failure(secp_ctx, logger, &source);
 959                 #[cfg(not(test))]
 960                 let (network_update, short_channel_id, payment_retryable, _, _) = onion_error.decode_onion_failure(secp_ctx, logger, &source);
 961
 962                 let mut session_priv_bytes = [0; 32];
 963                 session_priv_bytes.copy_from_slice(&session_priv[..]);
 964                 let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 965                 let mut all_paths_failed = false;
 966                 let mut full_failure_ev = None;
 967                 let mut pending_retry_ev = None;
 968                 let attempts_remaining = if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(*payment_id) {
 969                         if !payment.get_mut().remove(&session_priv_bytes, Some(&path)) {
 970                                 log_trace!(logger, "Received duplicative fail for HTLC with payment_hash {}", log_bytes!(payment_hash.0));
 971                                 return
 972                         }
 973                         if payment.get().is_fulfilled() {
 974                                 log_trace!(logger, "Received failure of HTLC with payment_hash {} after payment completion", log_bytes!(payment_hash.0));
 975                                 return
 976                         }
 977                         let is_retryable_now = payment.get().is_auto_retryable_now();
 978                         if let Some(scid) = short_channel_id {
 979                                 payment.get_mut().insert_previously_failed_scid(scid);
 980                         }
 981                         if payment.get().remaining_parts() == 0 {
 982                                 all_paths_failed = true;
 983                                 if payment.get().abandoned() {
 984                                         full_failure_ev = Some(events::Event::PaymentFailed {
 985                                                 payment_id: *payment_id,
 986                                                 payment_hash: payment.get().payment_hash().expect("PendingOutboundPayments::RetriesExceeded always has a payment hash set"),
 987                                         });
 988                                         payment.remove();
 989                                 }
 990                         }
 991                         is_retryable_now
 992                 } else {
 993                         log_trace!(logger, "Received duplicative fail for HTLC with payment_hash {}", log_bytes!(payment_hash.0));
 994                         return
 995                 };
 996                 core::mem::drop(outbounds);
 997                 let mut retry = if let Some(payment_params_data) = payment_params {
 998                         let path_last_hop = path.last().expect("Outbound payments must have had a valid path");
 999                         Some(RouteParameters {
1000                                 payment_params: payment_params_data.clone(),
1001                                 final_value_msat: path_last_hop.fee_msat,
1002                                 final_cltv_expiry_delta:
1003                                         if let Some(delta) = payment_params_data.final_cltv_expiry_delta { delta }
1004                                         else { path_last_hop.cltv_expiry_delta },
1005                         })
1006                 } else { None };
1007                 log_trace!(logger, "Failing outbound payment HTLC with payment_hash {}", log_bytes!(payment_hash.0));
1008
1009                 let path_failure = {
1010                         if payment_is_probe(payment_hash, &payment_id, probing_cookie_secret) {
1011                                 if !payment_retryable {
1012                                         events::Event::ProbeSuccessful {
1013                                                 payment_id: *payment_id,
1014                                                 payment_hash: payment_hash.clone(),
1015                                                 path: path.clone(),
1016                                         }
1017                                 } else {
1018                                         events::Event::ProbeFailed {
1019                                                 payment_id: *payment_id,
1020                                                 payment_hash: payment_hash.clone(),
1021                                                 path: path.clone(),
1022                                                 short_channel_id,
1023                                         }
1024                                 }
1025                         } else {
1026                                 // TODO: If we decided to blame ourselves (or one of our channels) in
1027                                 // process_onion_failure we should close that channel as it implies our
1028                                 // next-hop is needlessly blaming us!
1029                                 if let Some(scid) = short_channel_id {
1030                                         retry.as_mut().map(|r| r.payment_params.previously_failed_channels.push(scid));
1031                                 }
1032                                 if payment_retryable && attempts_remaining && retry.is_some() {
1033                                         debug_assert!(full_failure_ev.is_none());
1034                                         pending_retry_ev = Some(events::Event::PendingHTLCsForwardable {
1035                                                 time_forwardable: Duration::from_millis(MIN_HTLC_RELAY_HOLDING_CELL_MILLIS),
1036                                         });
1037                                 }
1038                                 events::Event::PaymentPathFailed {
1039                                         payment_id: Some(*payment_id),
1040                                         payment_hash: payment_hash.clone(),
1041                                         payment_failed_permanently: !payment_retryable,
1042                                         network_update,
1043                                         all_paths_failed,
1044                                         path: path.clone(),
1045                                         short_channel_id,
1046                                         retry,
1047                                         #[cfg(test)]
1048                                         error_code: onion_error_code,
1049                                         #[cfg(test)]
1050                                         error_data: onion_error_data
1051                                 }
1052                         }
1053                 };
1054                 let mut pending_events = pending_events.lock().unwrap();
1055                 pending_events.push(path_failure);
1056                 if let Some(ev) = full_failure_ev { pending_events.push(ev); }
1057                 if let Some(ev) = pending_retry_ev { pending_events.push(ev); }
1058         }
1059
1060         pub(super) fn abandon_payment(&self, payment_id: PaymentId) -> Option<events::Event> {
1061                 let mut failed_ev = None;
1062                 let mut outbounds = self.pending_outbound_payments.lock().unwrap();
1063                 if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(payment_id) {
1064                         if let Ok(()) = payment.get_mut().mark_abandoned() {
1065                                 if payment.get().remaining_parts() == 0 {
1066                                         failed_ev = Some(events::Event::PaymentFailed {
1067                                                 payment_id,
1068                                                 payment_hash: payment.get().payment_hash().expect("PendingOutboundPayments::RetriesExceeded always has a payment hash set"),
1069                                         });
1070                                         payment.remove();
1071                                 }
1072                         }
1073                 }
1074                 failed_ev
1075         }
1076
1077         #[cfg(test)]
1078         pub fn has_pending_payments(&self) -> bool {
1079                 !self.pending_outbound_payments.lock().unwrap().is_empty()
1080         }
1081
1082         #[cfg(test)]
1083         pub fn clear_pending_payments(&self) {
1084                 self.pending_outbound_payments.lock().unwrap().clear()
1085         }
1086 }
1087
1088 /// Returns whether a payment with the given [`PaymentHash`] and [`PaymentId`] is, in fact, a
1089 /// payment probe.
1090 pub(super) fn payment_is_probe(payment_hash: &PaymentHash, payment_id: &PaymentId,
1091         probing_cookie_secret: [u8; 32]) -> bool
1092 {
1093         let target_payment_hash = probing_cookie_from_id(payment_id, probing_cookie_secret);
1094         target_payment_hash == *payment_hash
1095 }
1096
1097 /// Returns the 'probing cookie' for the given [`PaymentId`].
1098 fn probing_cookie_from_id(payment_id: &PaymentId, probing_cookie_secret: [u8; 32]) -> PaymentHash {
1099         let mut preimage = [0u8; 64];
1100         preimage[..32].copy_from_slice(&probing_cookie_secret);
1101         preimage[32..].copy_from_slice(&payment_id.0);
1102         PaymentHash(Sha256::hash(&preimage).into_inner())
1103 }
1104
1105 impl_writeable_tlv_based_enum_upgradable!(PendingOutboundPayment,
1106         (0, Legacy) => {
1107                 (0, session_privs, required),
1108         },
1109         (1, Fulfilled) => {
1110                 (0, session_privs, required),
1111                 (1, payment_hash, option),
1112                 (3, timer_ticks_without_htlcs, (default_value, 0)),
1113         },
1114         (2, Retryable) => {
1115                 (0, session_privs, required),
1116                 (1, pending_fee_msat, option),
1117                 (2, payment_hash, required),
1118                 (not_written, retry_strategy, (static_value, None)),
1119                 (4, payment_secret, option),
1120                 (not_written, attempts, (static_value, PaymentAttempts::new())),
1121                 (6, total_msat, required),
1122                 (not_written, route_params, (static_value, None)),
1123                 (8, pending_amt_msat, required),
1124                 (10, starting_block_height, required),
1125         },
1126         (3, Abandoned) => {
1127                 (0, session_privs, required),
1128                 (2, payment_hash, required),
1129         },
1130 );
1131
1132 #[cfg(test)]
1133 mod tests {
1134         use bitcoin::blockdata::constants::genesis_block;
1135         use bitcoin::network::constants::Network;
1136         use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey};
1137
1138         use crate::ln::PaymentHash;
1139         use crate::ln::channelmanager::{PaymentId, PaymentSendFailure};
1140         use crate::ln::msgs::{ErrorAction, LightningError};
1141         use crate::ln::outbound_payment::{OutboundPayments, Retry};
1142         use crate::routing::gossip::NetworkGraph;
1143         use crate::routing::router::{InFlightHtlcs, PaymentParameters, Route, RouteParameters};
1144         use crate::sync::Arc;
1145         use crate::util::errors::APIError;
1146         use crate::util::test_utils;
1147
1148         #[test]
1149         #[cfg(feature = "std")]
1150         fn fails_paying_after_expiration() {
1151                 do_fails_paying_after_expiration(false);
1152                 do_fails_paying_after_expiration(true);
1153         }
1154         #[cfg(feature = "std")]
1155         fn do_fails_paying_after_expiration(on_retry: bool) {
1156                 let outbound_payments = OutboundPayments::new();
1157                 let logger = test_utils::TestLogger::new();
1158                 let genesis_hash = genesis_block(Network::Testnet).header.block_hash();
1159                 let network_graph = Arc::new(NetworkGraph::new(genesis_hash, &logger));
1160                 let router = test_utils::TestRouter::new(network_graph);
1161                 let secp_ctx = Secp256k1::new();
1162                 let keys_manager = test_utils::TestKeysInterface::new(&[0; 32], Network::Testnet);
1163
1164                 let past_expiry_time = std::time::SystemTime::UNIX_EPOCH.elapsed().unwrap().as_secs() - 2;
1165                 let payment_params = PaymentParameters::from_node_id(
1166                                 PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap()),
1167                                 0
1168                         ).with_expiry_time(past_expiry_time);
1169                 let expired_route_params = RouteParameters {
1170                         payment_params,
1171                         final_value_msat: 0,
1172                         final_cltv_expiry_delta: 0,
1173                 };
1174                 let err = if on_retry {
1175                         outbound_payments.pay_internal(
1176                                 PaymentId([0; 32]), None, expired_route_params, &&router, vec![], InFlightHtlcs::new(),
1177                                 &&keys_manager, &&keys_manager, 0, &&logger, &|_, _, _, _, _, _, _, _, _| Ok(())).unwrap_err()
1178                 } else {
1179                         outbound_payments.send_payment(
1180                                 PaymentHash([0; 32]), &None, PaymentId([0; 32]), Retry::Attempts(0), expired_route_params,
1181                                 &&router, vec![], InFlightHtlcs::new(), &&keys_manager, &&keys_manager, 0, &&logger,
1182                                 |_, _, _, _, _, _, _, _, _| Ok(())).unwrap_err()
1183                 };
1184                 if let PaymentSendFailure::ParameterError(APIError::APIMisuseError { err }) = err {
1185                         assert!(err.contains("Invoice expired"));
1186                 } else { panic!("Unexpected error"); }
1187         }
1188
1189         #[test]
1190         fn find_route_error() {
1191                 do_find_route_error(false);
1192                 do_find_route_error(true);
1193         }
1194         fn do_find_route_error(on_retry: bool) {
1195                 let outbound_payments = OutboundPayments::new();
1196                 let logger = test_utils::TestLogger::new();
1197                 let genesis_hash = genesis_block(Network::Testnet).header.block_hash();
1198                 let network_graph = Arc::new(NetworkGraph::new(genesis_hash, &logger));
1199                 let router = test_utils::TestRouter::new(network_graph);
1200                 let secp_ctx = Secp256k1::new();
1201                 let keys_manager = test_utils::TestKeysInterface::new(&[0; 32], Network::Testnet);
1202
1203                 let payment_params = PaymentParameters::from_node_id(
1204                         PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap()), 0);
1205                 let route_params = RouteParameters {
1206                         payment_params,
1207                         final_value_msat: 0,
1208                         final_cltv_expiry_delta: 0,
1209                 };
1210                 router.expect_find_route(route_params.clone(),
1211                         Err(LightningError { err: String::new(), action: ErrorAction::IgnoreError }));
1212
1213                 let err = if on_retry {
1214                         outbound_payments.add_new_pending_payment(PaymentHash([0; 32]), None, PaymentId([0; 32]),
1215                         &Route { paths: vec![], payment_params: None }, Some(Retry::Attempts(1)), Some(route_params.clone()),
1216                         &&keys_manager, 0).unwrap();
1217                         outbound_payments.pay_internal(
1218                                 PaymentId([0; 32]), None, route_params, &&router, vec![], InFlightHtlcs::new(),
1219                                 &&keys_manager, &&keys_manager, 0, &&logger, &|_, _, _, _, _, _, _, _, _| Ok(())).unwrap_err()
1220                 } else {
1221                         outbound_payments.send_payment(
1222                                 PaymentHash([0; 32]), &None, PaymentId([0; 32]), Retry::Attempts(0), route_params,
1223                                 &&router, vec![], InFlightHtlcs::new(), &&keys_manager, &&keys_manager, 0, &&logger,
1224                                 |_, _, _, _, _, _, _, _, _| Ok(())).unwrap_err()
1225                 };
1226                 if let PaymentSendFailure::ParameterError(APIError::APIMisuseError { err }) = err {
1227                         assert!(err.contains("Failed to find a route"));
1228                 } else { panic!("Unexpected error"); }
1229         }
1230 }