git.bitcoin.ninja 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, you do not need to call
 327         /// [`ChannelManager::abandon_payment`] and [`ChannelManager::retry_payment`] will *not* work
 328         /// for this payment.
 329         ///
 330         /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
 331         /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
 332         ParameterError(APIError),
 333         /// A parameter in a single path which was passed to send_payment was invalid, preventing us
 334         /// from attempting to send the payment at all.
 335         ///
 336         /// You can freely resend the payment in full (with the parameter error fixed).
 337         ///
 338         /// The results here are ordered the same as the paths in the route object which was passed to
 339         /// send_payment.
 340         ///
 341         /// Because the payment failed outright, no payment tracking is done, you do not need to call
 342         /// [`ChannelManager::abandon_payment`] and [`ChannelManager::retry_payment`] will *not* work
 343         /// for this payment.
 344         ///
 345         /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
 346         /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
 347         PathParameterError(Vec<Result<(), APIError>>),
 348         /// All paths which were attempted failed to send, with no channel state change taking place.
 349         /// You can freely resend the payment in full (though you probably want to do so over different
 350         /// paths than the ones selected).
 351         ///
 352         /// Because the payment failed outright, no payment tracking is done, you do not need to call
 353         /// [`ChannelManager::abandon_payment`] and [`ChannelManager::retry_payment`] will *not* work
 354         /// for this payment.
 355         ///
 356         /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
 357         /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
 358         AllFailedResendSafe(Vec<APIError>),
 359         /// Indicates that a payment for the provided [`PaymentId`] is already in-flight and has not
 360         /// yet completed (i.e. generated an [`Event::PaymentSent`]) or been abandoned (via
 361         /// [`ChannelManager::abandon_payment`]).
 362         ///
 363         /// [`PaymentId`]: crate::ln::channelmanager::PaymentId
 364         /// [`Event::PaymentSent`]: crate::util::events::Event::PaymentSent
 365         /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
 366         DuplicatePayment,
 367         /// Some paths which were attempted failed to send, though possibly not all. At least some
 368         /// paths have irrevocably committed to the HTLC and retrying the payment in full would result
 369         /// in over-/re-payment.
 370         ///
 371         /// The results here are ordered the same as the paths in the route object which was passed to
 372         /// send_payment, and any `Err`s which are not [`APIError::MonitorUpdateInProgress`] can be
 373         /// safely retried via [`ChannelManager::retry_payment`].
 374         ///
 375         /// Any entries which contain `Err(APIError::MonitorUpdateInprogress)` or `Ok(())` MUST NOT be
 376         /// retried as they will result in over-/re-payment. These HTLCs all either successfully sent
 377         /// (in the case of `Ok(())`) or will send once a [`MonitorEvent::Completed`] is provided for
 378         /// the next-hop channel with the latest update_id.
 379         ///
 380         /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
 381         /// [`MonitorEvent::Completed`]: crate::chain::channelmonitor::MonitorEvent::Completed
 382         PartialFailure {
 383                 /// The errors themselves, in the same order as the route hops.
 384                 results: Vec<Result<(), APIError>>,
 385                 /// If some paths failed without irrevocably committing to the new HTLC(s), this will
 386                 /// contain a [`RouteParameters`] object which can be used to calculate a new route that
 387                 /// will pay all remaining unpaid balance.
 388                 failed_paths_retry: Option<RouteParameters>,
 389                 /// The payment id for the payment, which is now at least partially pending.
 390                 payment_id: PaymentId,
 391         },
 392 }
 393
 394 pub(super) struct OutboundPayments {
 395         pub(super) pending_outbound_payments: Mutex<HashMap<PaymentId, PendingOutboundPayment>>,
 396 }
 397
 398 impl OutboundPayments {
 399         pub(super) fn new() -> Self {
 400                 Self {
 401                         pending_outbound_payments: Mutex::new(HashMap::new())
 402                 }
 403         }
 404
 405         pub(super) fn send_payment<R: Deref, ES: Deref, NS: Deref, F, L: Deref>(
 406                 &self, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>, payment_id: PaymentId,
 407                 retry_strategy: Retry, route_params: RouteParameters, router: &R,
 408                 first_hops: Vec<ChannelDetails>, inflight_htlcs: InFlightHtlcs, entropy_source: &ES,
 409                 node_signer: &NS, best_block_height: u32, logger: &L, send_payment_along_path: F,
 410         ) -> Result<(), PaymentSendFailure>
 411         where
 412                 R::Target: Router,
 413                 ES::Target: EntropySource,
 414                 NS::Target: NodeSigner,
 415                 L::Target: Logger,
 416                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 417                          u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>,
 418         {
 419                 self.pay_internal(payment_id, Some((payment_hash, payment_secret, retry_strategy)),
 420                         route_params, router, first_hops, inflight_htlcs, entropy_source, node_signer,
 421                         best_block_height, logger, &send_payment_along_path)
 422                         .map_err(|e| { self.remove_outbound_if_all_failed(payment_id, &e); e })
 423         }
 424
 425         pub(super) fn send_payment_with_route<ES: Deref, NS: Deref, F>(
 426                 &self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>,
 427                 payment_id: PaymentId, entropy_source: &ES, node_signer: &NS, best_block_height: u32,
 428                 send_payment_along_path: F
 429         ) -> Result<(), PaymentSendFailure>
 430         where
 431                 ES::Target: EntropySource,
 432                 NS::Target: NodeSigner,
 433                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 434                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 435         {
 436                 let onion_session_privs = self.add_new_pending_payment(payment_hash, *payment_secret, payment_id, None, route, None, None, entropy_source, best_block_height)?;
 437                 self.pay_route_internal(route, payment_hash, payment_secret, None, payment_id, None,
 438                         onion_session_privs, node_signer, best_block_height, &send_payment_along_path)
 439                         .map_err(|e| { self.remove_outbound_if_all_failed(payment_id, &e); e })
 440         }
 441
 442         pub(super) fn send_spontaneous_payment<ES: Deref, NS: Deref, F>(
 443                 &self, route: &Route, payment_preimage: Option<PaymentPreimage>, payment_id: PaymentId,
 444                 entropy_source: &ES, node_signer: &NS, best_block_height: u32, send_payment_along_path: F
 445         ) -> Result<PaymentHash, PaymentSendFailure>
 446         where
 447                 ES::Target: EntropySource,
 448                 NS::Target: NodeSigner,
 449                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 450                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 451         {
 452                 let preimage = match payment_preimage {
 453                         Some(p) => p,
 454                         None => PaymentPreimage(entropy_source.get_secure_random_bytes()),
 455                 };
 456                 let payment_hash = PaymentHash(Sha256::hash(&preimage.0).into_inner());
 457                 let onion_session_privs = self.add_new_pending_payment(payment_hash, None, payment_id, Some(preimage), &route, None, None, entropy_source, best_block_height)?;
 458
 459                 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) {
 460                         Ok(()) => Ok(payment_hash),
 461                         Err(e) => {
 462                                 self.remove_outbound_if_all_failed(payment_id, &e);
 463                                 Err(e)
 464                         }
 465                 }
 466         }
 467
 468         pub(super) fn check_retry_payments<R: Deref, ES: Deref, NS: Deref, SP, IH, FH, L: Deref>(
 469                 &self, router: &R, first_hops: FH, inflight_htlcs: IH, entropy_source: &ES, node_signer: &NS,
 470                 best_block_height: u32, logger: &L, send_payment_along_path: SP,
 471         )
 472         where
 473                 R::Target: Router,
 474                 ES::Target: EntropySource,
 475                 NS::Target: NodeSigner,
 476                 SP: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 477                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>,
 478                 IH: Fn() -> InFlightHtlcs,
 479                 FH: Fn() -> Vec<ChannelDetails>,
 480                 L::Target: Logger,
 481         {
 482                 loop {
 483                         let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 484                         let mut retry_id_route_params = None;
 485                         for (pmt_id, pmt) in outbounds.iter_mut() {
 486                                 if pmt.is_auto_retryable_now() {
 487                                         if let PendingOutboundPayment::Retryable { pending_amt_msat, total_msat, payment_params: Some(params), .. } = pmt {
 488                                                 if pending_amt_msat < total_msat {
 489                                                         retry_id_route_params = Some((*pmt_id, RouteParameters {
 490                                                                 final_value_msat: *total_msat - *pending_amt_msat,
 491                                                                 final_cltv_expiry_delta:
 492                                                                         if let Some(delta) = params.final_cltv_expiry_delta { delta }
 493                                                                         else {
 494                                                                                 debug_assert!(false, "We always set the final_cltv_expiry_delta when a path fails");
 495                                                                                 LDK_DEFAULT_MIN_FINAL_CLTV_EXPIRY_DELTA.into()
 496                                                                         },
 497                                                                 payment_params: params.clone(),
 498                                                         }));
 499                                                         break
 500                                                 }
 501                                         }
 502                                 }
 503                         }
 504                         if let Some((payment_id, route_params)) = retry_id_route_params {
 505                                 core::mem::drop(outbounds);
 506                                 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) {
 507                                         log_info!(logger, "Errored retrying payment: {:?}", e);
 508                                 }
 509                         } else { break }
 510                 }
 511         }
 512
 513         fn pay_internal<R: Deref, NS: Deref, ES: Deref, F, L: Deref>(
 514                 &self, payment_id: PaymentId,
 515                 initial_send_info: Option<(PaymentHash, &Option<PaymentSecret>, Retry)>,
 516                 route_params: RouteParameters, router: &R, first_hops: Vec<ChannelDetails>,
 517                 inflight_htlcs: InFlightHtlcs, entropy_source: &ES, node_signer: &NS, best_block_height: u32,
 518                 logger: &L, send_payment_along_path: &F,
 519         ) -> Result<(), PaymentSendFailure>
 520         where
 521                 R::Target: Router,
 522                 ES::Target: EntropySource,
 523                 NS::Target: NodeSigner,
 524                 L::Target: Logger,
 525                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 526                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 527         {
 528                 #[cfg(feature = "std")] {
 529                         if has_expired(&route_params) {
 530                                 return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 531                                         err: format!("Invoice expired for payment id {}", log_bytes!(payment_id.0)),
 532                                 }))
 533                         }
 534                 }
 535
 536                 let route = router.find_route(
 537                         &node_signer.get_node_id(Recipient::Node).unwrap(), &route_params,
 538                         Some(&first_hops.iter().collect::<Vec<_>>()), &inflight_htlcs
 539                 ).map_err(|e| PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 540                         err: format!("Failed to find a route for payment {}: {:?}", log_bytes!(payment_id.0), e), // TODO: add APIError::RouteNotFound
 541                 }))?;
 542
 543                 let res = if let Some((payment_hash, payment_secret, retry_strategy)) = initial_send_info {
 544                         let onion_session_privs = self.add_new_pending_payment(payment_hash, *payment_secret, payment_id, None, &route, Some(retry_strategy), Some(route_params.payment_params.clone()), entropy_source, best_block_height)?;
 545                         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)
 546                 } else {
 547                         self.retry_payment_with_route(&route, payment_id, entropy_source, node_signer, best_block_height, send_payment_along_path)
 548                 };
 549                 match res {
 550                         Err(PaymentSendFailure::AllFailedResendSafe(_)) => {
 551                                 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);
 552                                 log_info!(logger, "Result retrying payment id {}: {:?}", log_bytes!(payment_id.0), retry_res);
 553                                 if let Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError { err })) = &retry_res {
 554                                         if err.starts_with("Retries exhausted ") { return res; }
 555                                 }
 556                                 retry_res
 557                         },
 558                         Err(PaymentSendFailure::PartialFailure { failed_paths_retry: Some(retry), .. }) => {
 559                                 // Some paths were sent, even if we failed to send the full MPP value our recipient may
 560                                 // misbehave and claim the funds, at which point we have to consider the payment sent, so
 561                                 // return `Ok()` here, ignoring any retry errors.
 562                                 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);
 563                                 log_info!(logger, "Result retrying payment id {}: {:?}", log_bytes!(payment_id.0), retry_res);
 564                                 Ok(())
 565                         },
 566                         Err(PaymentSendFailure::PartialFailure { failed_paths_retry: None, .. }) => {
 567                                 // This may happen if we send a payment and some paths fail, but only due to a temporary
 568                                 // monitor failure or the like, implying they're really in-flight, but we haven't sent the
 569                                 // initial HTLC-Add messages yet.
 570                                 Ok(())
 571                         },
 572                         res => res,
 573                 }
 574         }
 575
 576         pub(super) fn retry_payment_with_route<ES: Deref, NS: Deref, F>(
 577                 &self, route: &Route, payment_id: PaymentId, entropy_source: &ES, node_signer: &NS, best_block_height: u32,
 578                 send_payment_along_path: F
 579         ) -> Result<(), PaymentSendFailure>
 580         where
 581                 ES::Target: EntropySource,
 582                 NS::Target: NodeSigner,
 583                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 584                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 585         {
 586                 const RETRY_OVERFLOW_PERCENTAGE: u64 = 10;
 587                 for path in route.paths.iter() {
 588                         if path.len() == 0 {
 589                                 return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 590                                         err: "length-0 path in route".to_string()
 591                                 }))
 592                         }
 593                 }
 594
 595                 let mut onion_session_privs = Vec::with_capacity(route.paths.len());
 596                 for _ in 0..route.paths.len() {
 597                         onion_session_privs.push(entropy_source.get_secure_random_bytes());
 598                 }
 599
 600                 let (total_msat, payment_hash, payment_secret) = {
 601                         let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 602                         match outbounds.get_mut(&payment_id) {
 603                                 Some(payment) => {
 604                                         let res = match payment {
 605                                                 PendingOutboundPayment::Retryable {
 606                                                         total_msat, payment_hash, payment_secret, pending_amt_msat, ..
 607                                                 } => {
 608                                                         let retry_amt_msat: u64 = route.paths.iter().map(|path| path.last().unwrap().fee_msat).sum();
 609                                                         if retry_amt_msat + *pending_amt_msat > *total_msat * (100 + RETRY_OVERFLOW_PERCENTAGE) / 100 {
 610                                                                 return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 611                                                                         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()
 612                                                                 }))
 613                                                         }
 614                                                         (*total_msat, *payment_hash, *payment_secret)
 615                                                 },
 616                                                 PendingOutboundPayment::Legacy { .. } => {
 617                                                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 618                                                                 err: "Unable to retry payments that were initially sent on LDK versions prior to 0.0.102".to_string()
 619                                                         }))
 620                                                 },
 621                                                 PendingOutboundPayment::Fulfilled { .. } => {
 622                                                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 623                                                                 err: "Payment already completed".to_owned()
 624                                                         }));
 625                                                 },
 626                                                 PendingOutboundPayment::Abandoned { .. } => {
 627                                                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 628                                                                 err: "Payment already abandoned (with some HTLCs still pending)".to_owned()
 629                                                         }));
 630                                                 },
 631                                         };
 632                                         if !payment.is_retryable_now() {
 633                                                 return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 634                                                         err: format!("Retries exhausted for payment id {}", log_bytes!(payment_id.0)),
 635                                                 }))
 636                                         }
 637                                         payment.increment_attempts();
 638                                         for (path, session_priv_bytes) in route.paths.iter().zip(onion_session_privs.iter()) {
 639                                                 assert!(payment.insert(*session_priv_bytes, path));
 640                                         }
 641                                         res
 642                                 },
 643                                 None =>
 644                                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 645                                                 err: format!("Payment with ID {} not found", log_bytes!(payment_id.0)),
 646                                         })),
 647                         }
 648                 };
 649                 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)
 650         }
 651
 652         pub(super) fn send_probe<ES: Deref, NS: Deref, F>(
 653                 &self, hops: Vec<RouteHop>, probing_cookie_secret: [u8; 32], entropy_source: &ES,
 654                 node_signer: &NS, best_block_height: u32, send_payment_along_path: F
 655         ) -> Result<(PaymentHash, PaymentId), PaymentSendFailure>
 656         where
 657                 ES::Target: EntropySource,
 658                 NS::Target: NodeSigner,
 659                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 660                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 661         {
 662                 let payment_id = PaymentId(entropy_source.get_secure_random_bytes());
 663
 664                 let payment_hash = probing_cookie_from_id(&payment_id, probing_cookie_secret);
 665
 666                 if hops.len() < 2 {
 667                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 668                                 err: "No need probing a path with less than two hops".to_string()
 669                         }))
 670                 }
 671
 672                 let route = Route { paths: vec![hops], payment_params: None };
 673                 let onion_session_privs = self.add_new_pending_payment(payment_hash, None, payment_id, None, &route, None, None, entropy_source, best_block_height)?;
 674
 675                 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) {
 676                         Ok(()) => Ok((payment_hash, payment_id)),
 677                         Err(e) => {
 678                                 self.remove_outbound_if_all_failed(payment_id, &e);
 679                                 Err(e)
 680                         }
 681                 }
 682         }
 683
 684         #[cfg(test)]
 685         pub(super) fn test_add_new_pending_payment<ES: Deref>(
 686                 &self, payment_hash: PaymentHash, payment_secret: Option<PaymentSecret>, payment_id: PaymentId,
 687                 route: &Route, retry_strategy: Option<Retry>, entropy_source: &ES, best_block_height: u32
 688         ) -> Result<Vec<[u8; 32]>, PaymentSendFailure> where ES::Target: EntropySource {
 689                 self.add_new_pending_payment(payment_hash, payment_secret, payment_id, None, route, retry_strategy, None, entropy_source, best_block_height)
 690         }
 691
 692         pub(super) fn add_new_pending_payment<ES: Deref>(
 693                 &self, payment_hash: PaymentHash, payment_secret: Option<PaymentSecret>, payment_id: PaymentId,
 694                 keysend_preimage: Option<PaymentPreimage>, route: &Route, retry_strategy: Option<Retry>,
 695                 payment_params: Option<PaymentParameters>, entropy_source: &ES, best_block_height: u32
 696         ) -> Result<Vec<[u8; 32]>, PaymentSendFailure> where ES::Target: EntropySource {
 697                 let mut onion_session_privs = Vec::with_capacity(route.paths.len());
 698                 for _ in 0..route.paths.len() {
 699                         onion_session_privs.push(entropy_source.get_secure_random_bytes());
 700                 }
 701
 702                 let mut pending_outbounds = self.pending_outbound_payments.lock().unwrap();
 703                 match pending_outbounds.entry(payment_id) {
 704                         hash_map::Entry::Occupied(_) => Err(PaymentSendFailure::DuplicatePayment),
 705                         hash_map::Entry::Vacant(entry) => {
 706                                 let payment = entry.insert(PendingOutboundPayment::Retryable {
 707                                         retry_strategy,
 708                                         attempts: PaymentAttempts::new(),
 709                                         payment_params,
 710                                         session_privs: HashSet::new(),
 711                                         pending_amt_msat: 0,
 712                                         pending_fee_msat: Some(0),
 713                                         payment_hash,
 714                                         payment_secret,
 715                                         keysend_preimage,
 716                                         starting_block_height: best_block_height,
 717                                         total_msat: route.get_total_amount(),
 718                                 });
 719
 720                                 for (path, session_priv_bytes) in route.paths.iter().zip(onion_session_privs.iter()) {
 721                                         assert!(payment.insert(*session_priv_bytes, path));
 722                                 }
 723
 724                                 Ok(onion_session_privs)
 725                         },
 726                 }
 727         }
 728
 729         fn pay_route_internal<NS: Deref, F>(
 730                 &self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>,
 731                 keysend_preimage: Option<PaymentPreimage>, payment_id: PaymentId, recv_value_msat: Option<u64>,
 732                 onion_session_privs: Vec<[u8; 32]>, node_signer: &NS, best_block_height: u32,
 733                 send_payment_along_path: &F
 734         ) -> Result<(), PaymentSendFailure>
 735         where
 736                 NS::Target: NodeSigner,
 737                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 738                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 739         {
 740                 if route.paths.len() < 1 {
 741                         return Err(PaymentSendFailure::ParameterError(APIError::InvalidRoute{err: "There must be at least one path to send over"}));
 742                 }
 743                 if payment_secret.is_none() && route.paths.len() > 1 {
 744                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError{err: "Payment secret is required for multi-path payments".to_string()}));
 745                 }
 746                 let mut total_value = 0;
 747                 let our_node_id = node_signer.get_node_id(Recipient::Node).unwrap(); // TODO no unwrap
 748                 let mut path_errs = Vec::with_capacity(route.paths.len());
 749                 'path_check: for path in route.paths.iter() {
 750                         if path.len() < 1 || path.len() > 20 {
 751                                 path_errs.push(Err(APIError::InvalidRoute{err: "Path didn't go anywhere/had bogus size"}));
 752                                 continue 'path_check;
 753                         }
 754                         for (idx, hop) in path.iter().enumerate() {
 755                                 if idx != path.len() - 1 && hop.pubkey == our_node_id {
 756                                         path_errs.push(Err(APIError::InvalidRoute{err: "Path went through us but wasn't a simple rebalance loop to us"}));
 757                                         continue 'path_check;
 758                                 }
 759                         }
 760                         total_value += path.last().unwrap().fee_msat;
 761                         path_errs.push(Ok(()));
 762                 }
 763                 if path_errs.iter().any(|e| e.is_err()) {
 764                         return Err(PaymentSendFailure::PathParameterError(path_errs));
 765                 }
 766                 if let Some(amt_msat) = recv_value_msat {
 767                         debug_assert!(amt_msat >= total_value);
 768                         total_value = amt_msat;
 769                 }
 770
 771                 let cur_height = best_block_height + 1;
 772                 let mut results = Vec::new();
 773                 debug_assert_eq!(route.paths.len(), onion_session_privs.len());
 774                 for (path, session_priv) in route.paths.iter().zip(onion_session_privs.into_iter()) {
 775                         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);
 776                         match path_res {
 777                                 Ok(_) => {},
 778                                 Err(APIError::MonitorUpdateInProgress) => {
 779                                         // While a MonitorUpdateInProgress is an Err(_), the payment is still
 780                                         // considered "in flight" and we shouldn't remove it from the
 781                                         // PendingOutboundPayment set.
 782                                 },
 783                                 Err(_) => {
 784                                         let mut pending_outbounds = self.pending_outbound_payments.lock().unwrap();
 785                                         if let Some(payment) = pending_outbounds.get_mut(&payment_id) {
 786                                                 let removed = payment.remove(&session_priv, Some(path));
 787                                                 debug_assert!(removed, "This can't happen as the payment has an entry for this path added by callers");
 788                                         } else {
 789                                                 debug_assert!(false, "This can't happen as the payment was added by callers");
 790                                                 path_res = Err(APIError::APIMisuseError { err: "Internal error: payment disappeared during processing. Please report this bug!".to_owned() });
 791                                         }
 792                                 }
 793                         }
 794                         results.push(path_res);
 795                 }
 796                 let mut has_ok = false;
 797                 let mut has_err = false;
 798                 let mut pending_amt_unsent = 0;
 799                 let mut max_unsent_cltv_delta = 0;
 800                 for (res, path) in results.iter().zip(route.paths.iter()) {
 801                         if res.is_ok() { has_ok = true; }
 802                         if res.is_err() { has_err = true; }
 803                         if let &Err(APIError::MonitorUpdateInProgress) = res {
 804                                 // MonitorUpdateInProgress is inherently unsafe to retry, so we call it a
 805                                 // PartialFailure.
 806                                 has_err = true;
 807                                 has_ok = true;
 808                         } else if res.is_err() {
 809                                 pending_amt_unsent += path.last().unwrap().fee_msat;
 810                                 max_unsent_cltv_delta = cmp::max(max_unsent_cltv_delta, path.last().unwrap().cltv_expiry_delta);
 811                         }
 812                 }
 813                 if has_err && has_ok {
 814                         Err(PaymentSendFailure::PartialFailure {
 815                                 results,
 816                                 payment_id,
 817                                 failed_paths_retry: if pending_amt_unsent != 0 {
 818                                         if let Some(payment_params) = &route.payment_params {
 819                                                 Some(RouteParameters {
 820                                                         payment_params: payment_params.clone(),
 821                                                         final_value_msat: pending_amt_unsent,
 822                                                         final_cltv_expiry_delta:
 823                                                                 if let Some(delta) = payment_params.final_cltv_expiry_delta { delta }
 824                                                                 else { max_unsent_cltv_delta },
 825                                                 })
 826                                         } else { None }
 827                                 } else { None },
 828                         })
 829                 } else if has_err {
 830                         Err(PaymentSendFailure::AllFailedResendSafe(results.drain(..).map(|r| r.unwrap_err()).collect()))
 831                 } else {
 832                         Ok(())
 833                 }
 834         }
 835
 836         #[cfg(test)]
 837         pub(super) fn test_send_payment_internal<NS: Deref, F>(
 838                 &self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>,
 839                 keysend_preimage: Option<PaymentPreimage>, payment_id: PaymentId, recv_value_msat: Option<u64>,
 840                 onion_session_privs: Vec<[u8; 32]>, node_signer: &NS, best_block_height: u32,
 841                 send_payment_along_path: F
 842         ) -> Result<(), PaymentSendFailure>
 843         where
 844                 NS::Target: NodeSigner,
 845                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 846                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 847         {
 848                 self.pay_route_internal(route, payment_hash, payment_secret, keysend_preimage, payment_id,
 849                         recv_value_msat, onion_session_privs, node_signer, best_block_height,
 850                         &send_payment_along_path)
 851                         .map_err(|e| { self.remove_outbound_if_all_failed(payment_id, &e); e })
 852         }
 853
 854         // If we failed to send any paths, we should remove the new PaymentId from the
 855         // `pending_outbound_payments` map, as the user isn't expected to `abandon_payment`.
 856         fn remove_outbound_if_all_failed(&self, payment_id: PaymentId, err: &PaymentSendFailure) {
 857                 if let &PaymentSendFailure::AllFailedResendSafe(_) = err {
 858                         let removed = self.pending_outbound_payments.lock().unwrap().remove(&payment_id).is_some();
 859                         debug_assert!(removed, "We should always have a pending payment to remove here");
 860                 }
 861         }
 862
 863         pub(super) fn claim_htlc<L: Deref>(
 864                 &self, payment_id: PaymentId, payment_preimage: PaymentPreimage, session_priv: SecretKey,
 865                 path: Vec<RouteHop>, from_onchain: bool, pending_events: &Mutex<Vec<events::Event>>, logger: &L
 866         ) where L::Target: Logger {
 867                 let mut session_priv_bytes = [0; 32];
 868                 session_priv_bytes.copy_from_slice(&session_priv[..]);
 869                 let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 870                 let mut pending_events = pending_events.lock().unwrap();
 871                 if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(payment_id) {
 872                         if !payment.get().is_fulfilled() {
 873                                 let payment_hash = PaymentHash(Sha256::hash(&payment_preimage.0).into_inner());
 874                                 let fee_paid_msat = payment.get().get_pending_fee_msat();
 875                                 pending_events.push(
 876                                         events::Event::PaymentSent {
 877                                                 payment_id: Some(payment_id),
 878                                                 payment_preimage,
 879                                                 payment_hash,
 880                                                 fee_paid_msat,
 881                                         }
 882                                 );
 883                                 payment.get_mut().mark_fulfilled();
 884                         }
 885
 886                         if from_onchain {
 887                                 // We currently immediately remove HTLCs which were fulfilled on-chain.
 888                                 // This could potentially lead to removing a pending payment too early,
 889                                 // with a reorg of one block causing us to re-add the fulfilled payment on
 890                                 // restart.
 891                                 // TODO: We should have a second monitor event that informs us of payments
 892                                 // irrevocably fulfilled.
 893                                 if payment.get_mut().remove(&session_priv_bytes, Some(&path)) {
 894                                         let payment_hash = Some(PaymentHash(Sha256::hash(&payment_preimage.0).into_inner()));
 895                                         pending_events.push(
 896                                                 events::Event::PaymentPathSuccessful {
 897                                                         payment_id,
 898                                                         payment_hash,
 899                                                         path,
 900                                                 }
 901                                         );
 902                                 }
 903                         }
 904                 } else {
 905                         log_trace!(logger, "Received duplicative fulfill for HTLC with payment_preimage {}", log_bytes!(payment_preimage.0));
 906                 }
 907         }
 908
 909         pub(super) fn finalize_claims(&self, sources: Vec<HTLCSource>, pending_events: &Mutex<Vec<events::Event>>) {
 910                 let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 911                 let mut pending_events = pending_events.lock().unwrap();
 912                 for source in sources {
 913                         if let HTLCSource::OutboundRoute { session_priv, payment_id, path, .. } = source {
 914                                 let mut session_priv_bytes = [0; 32];
 915                                 session_priv_bytes.copy_from_slice(&session_priv[..]);
 916                                 if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(payment_id) {
 917                                         assert!(payment.get().is_fulfilled());
 918                                         if payment.get_mut().remove(&session_priv_bytes, None) {
 919                                                 pending_events.push(
 920                                                         events::Event::PaymentPathSuccessful {
 921                                                                 payment_id,
 922                                                                 payment_hash: payment.get().payment_hash(),
 923                                                                 path,
 924                                                         }
 925                                                 );
 926                                         }
 927                                 }
 928                         }
 929                 }
 930         }
 931
 932         pub(super) fn remove_stale_resolved_payments(&self, pending_events: &Mutex<Vec<events::Event>>) {
 933                 // If an outbound payment was completed, and no pending HTLCs remain, we should remove it
 934                 // from the map. However, if we did that immediately when the last payment HTLC is claimed,
 935                 // this could race the user making a duplicate send_payment call and our idempotency
 936                 // guarantees would be violated. Instead, we wait a few timer ticks to do the actual
 937                 // removal. This should be more than sufficient to ensure the idempotency of any
 938                 // `send_payment` calls that were made at the same time the `PaymentSent` event was being
 939                 // processed.
 940                 let mut pending_outbound_payments = self.pending_outbound_payments.lock().unwrap();
 941                 let pending_events = pending_events.lock().unwrap();
 942                 pending_outbound_payments.retain(|payment_id, payment| {
 943                         if let PendingOutboundPayment::Fulfilled { session_privs, timer_ticks_without_htlcs, .. } = payment {
 944                                 let mut no_remaining_entries = session_privs.is_empty();
 945                                 if no_remaining_entries {
 946                                         for ev in pending_events.iter() {
 947                                                 match ev {
 948                                                         events::Event::PaymentSent { payment_id: Some(ev_payment_id), .. } |
 949                                                                 events::Event::PaymentPathSuccessful { payment_id: ev_payment_id, .. } |
 950                                                                 events::Event::PaymentPathFailed { payment_id: Some(ev_payment_id), .. } => {
 951                                                                         if payment_id == ev_payment_id {
 952                                                                                 no_remaining_entries = false;
 953                                                                                 break;
 954                                                                         }
 955                                                                 },
 956                                                         _ => {},
 957                                                 }
 958                                         }
 959                                 }
 960                                 if no_remaining_entries {
 961                                         *timer_ticks_without_htlcs += 1;
 962                                         *timer_ticks_without_htlcs <= IDEMPOTENCY_TIMEOUT_TICKS
 963                                 } else {
 964                                         *timer_ticks_without_htlcs = 0;
 965                                         true
 966                                 }
 967                         } else { true }
 968                 });
 969         }
 970
 971         pub(super) fn fail_htlc<L: Deref>(
 972                 &self, source: &HTLCSource, payment_hash: &PaymentHash, onion_error: &HTLCFailReason,
 973                 path: &Vec<RouteHop>, session_priv: &SecretKey, payment_id: &PaymentId,
 974                 payment_params: &Option<PaymentParameters>, probing_cookie_secret: [u8; 32],
 975                 secp_ctx: &Secp256k1<secp256k1::All>, pending_events: &Mutex<Vec<events::Event>>, logger: &L
 976         ) where L::Target: Logger {
 977                 #[cfg(test)]
 978                 let (network_update, short_channel_id, payment_retryable, onion_error_code, onion_error_data) = onion_error.decode_onion_failure(secp_ctx, logger, &source);
 979                 #[cfg(not(test))]
 980                 let (network_update, short_channel_id, payment_retryable, _, _) = onion_error.decode_onion_failure(secp_ctx, logger, &source);
 981
 982                 let mut session_priv_bytes = [0; 32];
 983                 session_priv_bytes.copy_from_slice(&session_priv[..]);
 984                 let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 985                 let mut all_paths_failed = false;
 986                 let mut full_failure_ev = None;
 987                 let mut pending_retry_ev = None;
 988                 let mut retry = None;
 989                 let attempts_remaining = if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(*payment_id) {
 990                         if !payment.get_mut().remove(&session_priv_bytes, Some(&path)) {
 991                                 log_trace!(logger, "Received duplicative fail for HTLC with payment_hash {}", log_bytes!(payment_hash.0));
 992                                 return
 993                         }
 994                         if payment.get().is_fulfilled() {
 995                                 log_trace!(logger, "Received failure of HTLC with payment_hash {} after payment completion", log_bytes!(payment_hash.0));
 996                                 return
 997                         }
 998                         let is_retryable_now = payment.get().is_auto_retryable_now();
 999                         if let Some(scid) = short_channel_id {
1000                                 payment.get_mut().insert_previously_failed_scid(scid);
1001                         }
1002
1003                         // We want to move towards only using the `PaymentParameters` in the outbound payments
1004                         // map. However, for backwards-compatibility, we still need to support passing the
1005                         // `PaymentParameters` data that was shoved in the HTLC (and given to us via
1006                         // `payment_params`) back to the user.
1007                         let path_last_hop = path.last().expect("Outbound payments must have had a valid path");
1008                         if let Some(params) = payment.get_mut().payment_parameters() {
1009                                 if params.final_cltv_expiry_delta.is_none() {
1010                                         // This should be rare, but a user could provide None for the payment data, and
1011                                         // we need it when we go to retry the payment, so fill it in.
1012                                         params.final_cltv_expiry_delta = Some(path_last_hop.cltv_expiry_delta);
1013                                 }
1014                                 retry = Some(RouteParameters {
1015                                         payment_params: params.clone(),
1016                                         final_value_msat: path_last_hop.fee_msat,
1017                                         final_cltv_expiry_delta: params.final_cltv_expiry_delta.unwrap(),
1018                                 });
1019                         } else if let Some(params) = payment_params {
1020                                 retry = Some(RouteParameters {
1021                                         payment_params: params.clone(),
1022                                         final_value_msat: path_last_hop.fee_msat,
1023                                         final_cltv_expiry_delta:
1024                                                 if let Some(delta) = params.final_cltv_expiry_delta { delta }
1025                                                 else { path_last_hop.cltv_expiry_delta },
1026                                 });
1027                         }
1028
1029                         if payment.get().remaining_parts() == 0 {
1030                                 all_paths_failed = true;
1031                                 if payment.get().abandoned() {
1032                                         full_failure_ev = Some(events::Event::PaymentFailed {
1033                                                 payment_id: *payment_id,
1034                                                 payment_hash: payment.get().payment_hash().expect("PendingOutboundPayments::RetriesExceeded always has a payment hash set"),
1035                                         });
1036                                         payment.remove();
1037                                 }
1038                         }
1039                         is_retryable_now
1040                 } else {
1041                         log_trace!(logger, "Received duplicative fail for HTLC with payment_hash {}", log_bytes!(payment_hash.0));
1042                         return
1043                 };
1044                 core::mem::drop(outbounds);
1045                 log_trace!(logger, "Failing outbound payment HTLC with payment_hash {}", log_bytes!(payment_hash.0));
1046
1047                 let path_failure = {
1048                         if payment_is_probe(payment_hash, &payment_id, probing_cookie_secret) {
1049                                 if !payment_retryable {
1050                                         events::Event::ProbeSuccessful {
1051                                                 payment_id: *payment_id,
1052                                                 payment_hash: payment_hash.clone(),
1053                                                 path: path.clone(),
1054                                         }
1055                                 } else {
1056                                         events::Event::ProbeFailed {
1057                                                 payment_id: *payment_id,
1058                                                 payment_hash: payment_hash.clone(),
1059                                                 path: path.clone(),
1060                                                 short_channel_id,
1061                                         }
1062                                 }
1063                         } else {
1064                                 // TODO: If we decided to blame ourselves (or one of our channels) in
1065                                 // process_onion_failure we should close that channel as it implies our
1066                                 // next-hop is needlessly blaming us!
1067                                 if let Some(scid) = short_channel_id {
1068                                         retry.as_mut().map(|r| r.payment_params.previously_failed_channels.push(scid));
1069                                 }
1070                                 if payment_retryable && attempts_remaining && retry.is_some() {
1071                                         debug_assert!(full_failure_ev.is_none());
1072                                         pending_retry_ev = Some(events::Event::PendingHTLCsForwardable {
1073                                                 time_forwardable: Duration::from_millis(MIN_HTLC_RELAY_HOLDING_CELL_MILLIS),
1074                                         });
1075                                 }
1076                                 events::Event::PaymentPathFailed {
1077                                         payment_id: Some(*payment_id),
1078                                         payment_hash: payment_hash.clone(),
1079                                         payment_failed_permanently: !payment_retryable,
1080                                         network_update,
1081                                         all_paths_failed,
1082                                         path: path.clone(),
1083                                         short_channel_id,
1084                                         retry,
1085                                         #[cfg(test)]
1086                                         error_code: onion_error_code,
1087                                         #[cfg(test)]
1088                                         error_data: onion_error_data
1089                                 }
1090                         }
1091                 };
1092                 let mut pending_events = pending_events.lock().unwrap();
1093                 pending_events.push(path_failure);
1094                 if let Some(ev) = full_failure_ev { pending_events.push(ev); }
1095                 if let Some(ev) = pending_retry_ev { pending_events.push(ev); }
1096         }
1097
1098         pub(super) fn abandon_payment(&self, payment_id: PaymentId) -> Option<events::Event> {
1099                 let mut failed_ev = None;
1100                 let mut outbounds = self.pending_outbound_payments.lock().unwrap();
1101                 if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(payment_id) {
1102                         if let Ok(()) = payment.get_mut().mark_abandoned() {
1103                                 if payment.get().remaining_parts() == 0 {
1104                                         failed_ev = Some(events::Event::PaymentFailed {
1105                                                 payment_id,
1106                                                 payment_hash: payment.get().payment_hash().expect("PendingOutboundPayments::RetriesExceeded always has a payment hash set"),
1107                                         });
1108                                         payment.remove();
1109                                 }
1110                         }
1111                 }
1112                 failed_ev
1113         }
1114
1115         #[cfg(test)]
1116         pub fn has_pending_payments(&self) -> bool {
1117                 !self.pending_outbound_payments.lock().unwrap().is_empty()
1118         }
1119
1120         #[cfg(test)]
1121         pub fn clear_pending_payments(&self) {
1122                 self.pending_outbound_payments.lock().unwrap().clear()
1123         }
1124 }
1125
1126 /// Returns whether a payment with the given [`PaymentHash`] and [`PaymentId`] is, in fact, a
1127 /// payment probe.
1128 pub(super) fn payment_is_probe(payment_hash: &PaymentHash, payment_id: &PaymentId,
1129         probing_cookie_secret: [u8; 32]) -> bool
1130 {
1131         let target_payment_hash = probing_cookie_from_id(payment_id, probing_cookie_secret);
1132         target_payment_hash == *payment_hash
1133 }
1134
1135 /// Returns the 'probing cookie' for the given [`PaymentId`].
1136 fn probing_cookie_from_id(payment_id: &PaymentId, probing_cookie_secret: [u8; 32]) -> PaymentHash {
1137         let mut preimage = [0u8; 64];
1138         preimage[..32].copy_from_slice(&probing_cookie_secret);
1139         preimage[32..].copy_from_slice(&payment_id.0);
1140         PaymentHash(Sha256::hash(&preimage).into_inner())
1141 }
1142
1143 impl_writeable_tlv_based_enum_upgradable!(PendingOutboundPayment,
1144         (0, Legacy) => {
1145                 (0, session_privs, required),
1146         },
1147         (1, Fulfilled) => {
1148                 (0, session_privs, required),
1149                 (1, payment_hash, option),
1150                 (3, timer_ticks_without_htlcs, (default_value, 0)),
1151         },
1152         (2, Retryable) => {
1153                 (0, session_privs, required),
1154                 (1, pending_fee_msat, option),
1155                 (2, payment_hash, required),
1156                 (3, payment_params, option),
1157                 (4, payment_secret, option),
1158                 (5, keysend_preimage, option),
1159                 (6, total_msat, required),
1160                 (8, pending_amt_msat, required),
1161                 (10, starting_block_height, required),
1162                 (not_written, retry_strategy, (static_value, None)),
1163                 (not_written, attempts, (static_value, PaymentAttempts::new())),
1164         },
1165         (3, Abandoned) => {
1166                 (0, session_privs, required),
1167                 (2, payment_hash, required),
1168         },
1169 );
1170
1171 #[cfg(test)]
1172 mod tests {
1173         use bitcoin::blockdata::constants::genesis_block;
1174         use bitcoin::network::constants::Network;
1175         use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey};
1176
1177         use crate::ln::PaymentHash;
1178         use crate::ln::channelmanager::{PaymentId, PaymentSendFailure};
1179         use crate::ln::msgs::{ErrorAction, LightningError};
1180         use crate::ln::outbound_payment::{OutboundPayments, Retry};
1181         use crate::routing::gossip::NetworkGraph;
1182         use crate::routing::router::{InFlightHtlcs, PaymentParameters, Route, RouteParameters};
1183         use crate::sync::Arc;
1184         use crate::util::errors::APIError;
1185         use crate::util::test_utils;
1186
1187         #[test]
1188         #[cfg(feature = "std")]
1189         fn fails_paying_after_expiration() {
1190                 do_fails_paying_after_expiration(false);
1191                 do_fails_paying_after_expiration(true);
1192         }
1193         #[cfg(feature = "std")]
1194         fn do_fails_paying_after_expiration(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 past_expiry_time = std::time::SystemTime::UNIX_EPOCH.elapsed().unwrap().as_secs() - 2;
1204                 let payment_params = PaymentParameters::from_node_id(
1205                                 PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap()),
1206                                 0
1207                         ).with_expiry_time(past_expiry_time);
1208                 let expired_route_params = RouteParameters {
1209                         payment_params,
1210                         final_value_msat: 0,
1211                         final_cltv_expiry_delta: 0,
1212                 };
1213                 let err = if on_retry {
1214                         outbound_payments.pay_internal(
1215                                 PaymentId([0; 32]), None, expired_route_params, &&router, vec![], InFlightHtlcs::new(),
1216                                 &&keys_manager, &&keys_manager, 0, &&logger, &|_, _, _, _, _, _, _, _, _| Ok(())).unwrap_err()
1217                 } else {
1218                         outbound_payments.send_payment(
1219                                 PaymentHash([0; 32]), &None, PaymentId([0; 32]), Retry::Attempts(0), expired_route_params,
1220                                 &&router, vec![], InFlightHtlcs::new(), &&keys_manager, &&keys_manager, 0, &&logger,
1221                                 |_, _, _, _, _, _, _, _, _| Ok(())).unwrap_err()
1222                 };
1223                 if let PaymentSendFailure::ParameterError(APIError::APIMisuseError { err }) = err {
1224                         assert!(err.contains("Invoice expired"));
1225                 } else { panic!("Unexpected error"); }
1226         }
1227
1228         #[test]
1229         fn find_route_error() {
1230                 do_find_route_error(false);
1231                 do_find_route_error(true);
1232         }
1233         fn do_find_route_error(on_retry: bool) {
1234                 let outbound_payments = OutboundPayments::new();
1235                 let logger = test_utils::TestLogger::new();
1236                 let genesis_hash = genesis_block(Network::Testnet).header.block_hash();
1237                 let network_graph = Arc::new(NetworkGraph::new(genesis_hash, &logger));
1238                 let router = test_utils::TestRouter::new(network_graph);
1239                 let secp_ctx = Secp256k1::new();
1240                 let keys_manager = test_utils::TestKeysInterface::new(&[0; 32], Network::Testnet);
1241
1242                 let payment_params = PaymentParameters::from_node_id(
1243                         PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap()), 0);
1244                 let route_params = RouteParameters {
1245                         payment_params,
1246                         final_value_msat: 0,
1247                         final_cltv_expiry_delta: 0,
1248                 };
1249                 router.expect_find_route(route_params.clone(),
1250                         Err(LightningError { err: String::new(), action: ErrorAction::IgnoreError }));
1251
1252                 let err = if on_retry {
1253                         outbound_payments.add_new_pending_payment(PaymentHash([0; 32]), None, PaymentId([0; 32]), None,
1254                                 &Route { paths: vec![], payment_params: None }, Some(Retry::Attempts(1)),
1255                                 Some(route_params.payment_params.clone()), &&keys_manager, 0).unwrap();
1256                         outbound_payments.pay_internal(
1257                                 PaymentId([0; 32]), None, route_params, &&router, vec![], InFlightHtlcs::new(),
1258                                 &&keys_manager, &&keys_manager, 0, &&logger, &|_, _, _, _, _, _, _, _, _| Ok(())).unwrap_err()
1259                 } else {
1260                         outbound_payments.send_payment(
1261                                 PaymentHash([0; 32]), &None, PaymentId([0; 32]), Retry::Attempts(0), route_params,
1262                                 &&router, vec![], InFlightHtlcs::new(), &&keys_manager, &&keys_manager, 0, &&logger,
1263                                 |_, _, _, _, _, _, _, _, _| Ok(())).unwrap_err()
1264                 };
1265                 if let PaymentSendFailure::ParameterError(APIError::APIMisuseError { err }) = err {
1266                         assert!(err.contains("Failed to find a route"));
1267                 } else { panic!("Unexpected error"); }
1268         }
1269 }