_ 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                 pending_amt_msat: u64,
  52                 /// Used to track the fee paid. Only present if the payment was serialized on 0.0.103+.
  53                 pending_fee_msat: Option<u64>,
  54                 /// The total payment amount across all paths, used to verify that a retry is not overpaying.
  55                 total_msat: u64,
  56                 /// Our best known block height at the time this payment was initiated.
  57                 starting_block_height: u32,
  58         },
  59         /// When a pending payment is fulfilled, we continue tracking it until all pending HTLCs have
  60         /// been resolved. This ensures we don't look up pending payments in ChannelMonitors on restart
  61         /// and add a pending payment that was already fulfilled.
  62         Fulfilled {
  63                 session_privs: HashSet<[u8; 32]>,
  64                 payment_hash: Option<PaymentHash>,
  65                 timer_ticks_without_htlcs: u8,
  66         },
  67         /// When a payer gives up trying to retry a payment, they inform us, letting us generate a
  68         /// `PaymentFailed` event when all HTLCs have irrevocably failed. This avoids a number of race
  69         /// conditions in MPP-aware payment retriers (1), where the possibility of multiple
  70         /// `PaymentPathFailed` events with `all_paths_failed` can be pending at once, confusing a
  71         /// downstream event handler as to when a payment has actually failed.
  72         ///
  73         /// (1) <https://github.com/lightningdevkit/rust-lightning/issues/1164>
  74         Abandoned {
  75                 session_privs: HashSet<[u8; 32]>,
  76                 payment_hash: PaymentHash,
  77         },
  78 }
  79
  80 impl PendingOutboundPayment {
  81         fn increment_attempts(&mut self) {
  82                 if let PendingOutboundPayment::Retryable { attempts, .. } = self {
  83                         attempts.count += 1;
  84                 }
  85         }
  86         fn is_auto_retryable_now(&self) -> bool {
  87                 match self {
  88                         PendingOutboundPayment::Retryable { retry_strategy: Some(strategy), attempts, .. } => {
  89                                 strategy.is_retryable_now(&attempts)
  90                         },
  91                         _ => false,
  92                 }
  93         }
  94         fn is_retryable_now(&self) -> bool {
  95                 match self {
  96                         PendingOutboundPayment::Retryable { retry_strategy: None, .. } => {
  97                                 // We're handling retries manually, we can always retry.
  98                                 true
  99                         },
 100                         PendingOutboundPayment::Retryable { retry_strategy: Some(strategy), attempts, .. } => {
 101                                 strategy.is_retryable_now(&attempts)
 102                         },
 103                         _ => false,
 104                 }
 105         }
 106         fn payment_parameters(&mut self) -> Option<&mut PaymentParameters> {
 107                 match self {
 108                         PendingOutboundPayment::Retryable { payment_params: Some(ref mut params), .. } => {
 109                                 Some(params)
 110                         },
 111                         _ => None,
 112                 }
 113         }
 114         pub fn insert_previously_failed_scid(&mut self, scid: u64) {
 115                 if let PendingOutboundPayment::Retryable { payment_params: Some(params), .. } = self {
 116                         params.previously_failed_channels.push(scid);
 117                 }
 118         }
 119         pub(super) fn is_fulfilled(&self) -> bool {
 120                 match self {
 121                         PendingOutboundPayment::Fulfilled { .. } => true,
 122                         _ => false,
 123                 }
 124         }
 125         pub(super) fn abandoned(&self) -> bool {
 126                 match self {
 127                         PendingOutboundPayment::Abandoned { .. } => true,
 128                         _ => false,
 129                 }
 130         }
 131         fn get_pending_fee_msat(&self) -> Option<u64> {
 132                 match self {
 133                         PendingOutboundPayment::Retryable { pending_fee_msat, .. } => pending_fee_msat.clone(),
 134                         _ => None,
 135                 }
 136         }
 137
 138         fn payment_hash(&self) -> Option<PaymentHash> {
 139                 match self {
 140                         PendingOutboundPayment::Legacy { .. } => None,
 141                         PendingOutboundPayment::Retryable { payment_hash, .. } => Some(*payment_hash),
 142                         PendingOutboundPayment::Fulfilled { payment_hash, .. } => *payment_hash,
 143                         PendingOutboundPayment::Abandoned { payment_hash, .. } => Some(*payment_hash),
 144                 }
 145         }
 146
 147         fn mark_fulfilled(&mut self) {
 148                 let mut session_privs = HashSet::new();
 149                 core::mem::swap(&mut session_privs, match self {
 150                         PendingOutboundPayment::Legacy { session_privs } |
 151                                 PendingOutboundPayment::Retryable { session_privs, .. } |
 152                                 PendingOutboundPayment::Fulfilled { session_privs, .. } |
 153                                 PendingOutboundPayment::Abandoned { session_privs, .. }
 154                         => session_privs,
 155                 });
 156                 let payment_hash = self.payment_hash();
 157                 *self = PendingOutboundPayment::Fulfilled { session_privs, payment_hash, timer_ticks_without_htlcs: 0 };
 158         }
 159
 160         fn mark_abandoned(&mut self) -> Result<(), ()> {
 161                 let mut session_privs = HashSet::new();
 162                 let our_payment_hash;
 163                 core::mem::swap(&mut session_privs, match self {
 164                         PendingOutboundPayment::Legacy { .. } |
 165                                 PendingOutboundPayment::Fulfilled { .. } =>
 166                                 return Err(()),
 167                                 PendingOutboundPayment::Retryable { session_privs, payment_hash, .. } |
 168                                         PendingOutboundPayment::Abandoned { session_privs, payment_hash, .. } => {
 169                                                 our_payment_hash = *payment_hash;
 170                                                 session_privs
 171                                         },
 172                 });
 173                 *self = PendingOutboundPayment::Abandoned { session_privs, payment_hash: our_payment_hash };
 174                 Ok(())
 175         }
 176
 177         /// panics if path is None and !self.is_fulfilled
 178         fn remove(&mut self, session_priv: &[u8; 32], path: Option<&Vec<RouteHop>>) -> bool {
 179                 let remove_res = match self {
 180                         PendingOutboundPayment::Legacy { session_privs } |
 181                                 PendingOutboundPayment::Retryable { session_privs, .. } |
 182                                 PendingOutboundPayment::Fulfilled { session_privs, .. } |
 183                                 PendingOutboundPayment::Abandoned { session_privs, .. } => {
 184                                         session_privs.remove(session_priv)
 185                                 }
 186                 };
 187                 if remove_res {
 188                         if let PendingOutboundPayment::Retryable { ref mut pending_amt_msat, ref mut pending_fee_msat, .. } = self {
 189                                 let path = path.expect("Fulfilling a payment should always come with a path");
 190                                 let path_last_hop = path.last().expect("Outbound payments must have had a valid path");
 191                                 *pending_amt_msat -= path_last_hop.fee_msat;
 192                                 if let Some(fee_msat) = pending_fee_msat.as_mut() {
 193                                         *fee_msat -= path.get_path_fees();
 194                                 }
 195                         }
 196                 }
 197                 remove_res
 198         }
 199
 200         pub(super) fn insert(&mut self, session_priv: [u8; 32], path: &Vec<RouteHop>) -> bool {
 201                 let insert_res = match self {
 202                         PendingOutboundPayment::Legacy { session_privs } |
 203                                 PendingOutboundPayment::Retryable { session_privs, .. } => {
 204                                         session_privs.insert(session_priv)
 205                                 }
 206                         PendingOutboundPayment::Fulfilled { .. } => false,
 207                         PendingOutboundPayment::Abandoned { .. } => false,
 208                 };
 209                 if insert_res {
 210                         if let PendingOutboundPayment::Retryable { ref mut pending_amt_msat, ref mut pending_fee_msat, .. } = self {
 211                                 let path_last_hop = path.last().expect("Outbound payments must have had a valid path");
 212                                 *pending_amt_msat += path_last_hop.fee_msat;
 213                                 if let Some(fee_msat) = pending_fee_msat.as_mut() {
 214                                         *fee_msat += path.get_path_fees();
 215                                 }
 216                         }
 217                 }
 218                 insert_res
 219         }
 220
 221         pub(super) fn remaining_parts(&self) -> usize {
 222                 match self {
 223                         PendingOutboundPayment::Legacy { session_privs } |
 224                                 PendingOutboundPayment::Retryable { session_privs, .. } |
 225                                 PendingOutboundPayment::Fulfilled { session_privs, .. } |
 226                                 PendingOutboundPayment::Abandoned { session_privs, .. } => {
 227                                         session_privs.len()
 228                                 }
 229                 }
 230         }
 231 }
 232
 233 /// Strategies available to retry payment path failures.
 234 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
 235 pub enum Retry {
 236         /// Max number of attempts to retry payment.
 237         ///
 238         /// Each attempt may be multiple HTLCs along multiple paths if the router decides to split up a
 239         /// retry, and may retry multiple failed HTLCs at once if they failed around the same time and
 240         /// were retried along a route from a single call to [`Router::find_route`].
 241         Attempts(usize),
 242         #[cfg(not(feature = "no-std"))]
 243         /// Time elapsed before abandoning retries for a payment.
 244         Timeout(core::time::Duration),
 245 }
 246
 247 impl Retry {
 248         pub(crate) fn is_retryable_now(&self, attempts: &PaymentAttempts) -> bool {
 249                 match (self, attempts) {
 250                         (Retry::Attempts(max_retry_count), PaymentAttempts { count, .. }) => {
 251                                 max_retry_count > count
 252                         },
 253                         #[cfg(all(not(feature = "no-std"), not(test)))]
 254                         (Retry::Timeout(max_duration), PaymentAttempts { first_attempted_at, .. }) =>
 255                                 *max_duration >= std::time::Instant::now().duration_since(*first_attempted_at),
 256                         #[cfg(all(not(feature = "no-std"), test))]
 257                         (Retry::Timeout(max_duration), PaymentAttempts { first_attempted_at, .. }) =>
 258                                 *max_duration >= SinceEpoch::now().duration_since(*first_attempted_at),
 259                 }
 260         }
 261 }
 262
 263 #[cfg(feature = "std")]
 264 pub(super) fn has_expired(route_params: &RouteParameters) -> bool {
 265         if let Some(expiry_time) = route_params.payment_params.expiry_time {
 266                 if let Ok(elapsed) = std::time::SystemTime::UNIX_EPOCH.elapsed() {
 267                         return elapsed > core::time::Duration::from_secs(expiry_time)
 268                 }
 269         }
 270         false
 271 }
 272
 273 pub(crate) type PaymentAttempts = PaymentAttemptsUsingTime<ConfiguredTime>;
 274
 275 /// Storing minimal payment attempts information required for determining if a outbound payment can
 276 /// be retried.
 277 pub(crate) struct PaymentAttemptsUsingTime<T: Time> {
 278         /// This count will be incremented only after the result of the attempt is known. When it's 0,
 279         /// it means the result of the first attempt is not known yet.
 280         pub(crate) count: usize,
 281         /// This field is only used when retry is `Retry::Timeout` which is only build with feature std
 282         first_attempted_at: T
 283 }
 284
 285 #[cfg(not(any(feature = "no-std", test)))]
 286 type ConfiguredTime = std::time::Instant;
 287 #[cfg(feature = "no-std")]
 288 type ConfiguredTime = crate::util::time::Eternity;
 289 #[cfg(all(not(feature = "no-std"), test))]
 290 type ConfiguredTime = SinceEpoch;
 291
 292 impl<T: Time> PaymentAttemptsUsingTime<T> {
 293         pub(crate) fn new() -> Self {
 294                 PaymentAttemptsUsingTime {
 295                         count: 0,
 296                         first_attempted_at: T::now()
 297                 }
 298         }
 299 }
 300
 301 impl<T: Time> Display for PaymentAttemptsUsingTime<T> {
 302         fn fmt(&self, f: &mut Formatter) -> Result<(), fmt::Error> {
 303                 #[cfg(feature = "no-std")]
 304                 return write!(f, "attempts: {}", self.count);
 305                 #[cfg(not(feature = "no-std"))]
 306                 return write!(
 307                         f,
 308                         "attempts: {}, duration: {}s",
 309                         self.count,
 310                         T::now().duration_since(self.first_attempted_at).as_secs()
 311                 );
 312         }
 313 }
 314
 315 /// If a payment fails to send, it can be in one of several states. This enum is returned as the
 316 /// Err() type describing which state the payment is in, see the description of individual enum
 317 /// states for more.
 318 #[derive(Clone, Debug)]
 319 pub enum PaymentSendFailure {
 320         /// A parameter which was passed to send_payment was invalid, preventing us from attempting to
 321         /// send the payment at all.
 322         ///
 323         /// You can freely resend the payment in full (with the parameter error fixed).
 324         ///
 325         /// Because the payment failed outright, no payment tracking is done, you do not need to call
 326         /// [`ChannelManager::abandon_payment`] and [`ChannelManager::retry_payment`] will *not* work
 327         /// for this payment.
 328         ///
 329         /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
 330         /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
 331         ParameterError(APIError),
 332         /// A parameter in a single path which was passed to send_payment was invalid, preventing us
 333         /// from attempting to send the payment at all.
 334         ///
 335         /// You can freely resend the payment in full (with the parameter error fixed).
 336         ///
 337         /// The results here are ordered the same as the paths in the route object which was passed to
 338         /// send_payment.
 339         ///
 340         /// Because the payment failed outright, no payment tracking is done, you do not need to call
 341         /// [`ChannelManager::abandon_payment`] and [`ChannelManager::retry_payment`] will *not* work
 342         /// for this payment.
 343         ///
 344         /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
 345         /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
 346         PathParameterError(Vec<Result<(), APIError>>),
 347         /// All paths which were attempted failed to send, with no channel state change taking place.
 348         /// You can freely resend the payment in full (though you probably want to do so over different
 349         /// paths than the ones selected).
 350         ///
 351         /// Because the payment failed outright, no payment tracking is done, you do not need to call
 352         /// [`ChannelManager::abandon_payment`] and [`ChannelManager::retry_payment`] will *not* work
 353         /// for this payment.
 354         ///
 355         /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
 356         /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
 357         AllFailedResendSafe(Vec<APIError>),
 358         /// Indicates that a payment for the provided [`PaymentId`] is already in-flight and has not
 359         /// yet completed (i.e. generated an [`Event::PaymentSent`]) or been abandoned (via
 360         /// [`ChannelManager::abandon_payment`]).
 361         ///
 362         /// [`PaymentId`]: crate::ln::channelmanager::PaymentId
 363         /// [`Event::PaymentSent`]: crate::util::events::Event::PaymentSent
 364         /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
 365         DuplicatePayment,
 366         /// Some paths which were attempted failed to send, though possibly not all. At least some
 367         /// paths have irrevocably committed to the HTLC and retrying the payment in full would result
 368         /// in over-/re-payment.
 369         ///
 370         /// The results here are ordered the same as the paths in the route object which was passed to
 371         /// send_payment, and any `Err`s which are not [`APIError::MonitorUpdateInProgress`] can be
 372         /// safely retried via [`ChannelManager::retry_payment`].
 373         ///
 374         /// Any entries which contain `Err(APIError::MonitorUpdateInprogress)` or `Ok(())` MUST NOT be
 375         /// retried as they will result in over-/re-payment. These HTLCs all either successfully sent
 376         /// (in the case of `Ok(())`) or will send once a [`MonitorEvent::Completed`] is provided for
 377         /// the next-hop channel with the latest update_id.
 378         ///
 379         /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
 380         /// [`MonitorEvent::Completed`]: crate::chain::channelmonitor::MonitorEvent::Completed
 381         PartialFailure {
 382                 /// The errors themselves, in the same order as the route hops.
 383                 results: Vec<Result<(), APIError>>,
 384                 /// If some paths failed without irrevocably committing to the new HTLC(s), this will
 385                 /// contain a [`RouteParameters`] object which can be used to calculate a new route that
 386                 /// will pay all remaining unpaid balance.
 387                 failed_paths_retry: Option<RouteParameters>,
 388                 /// The payment id for the payment, which is now at least partially pending.
 389                 payment_id: PaymentId,
 390         },
 391 }
 392
 393 pub(super) struct OutboundPayments {
 394         pub(super) pending_outbound_payments: Mutex<HashMap<PaymentId, PendingOutboundPayment>>,
 395 }
 396
 397 impl OutboundPayments {
 398         pub(super) fn new() -> Self {
 399                 Self {
 400                         pending_outbound_payments: Mutex::new(HashMap::new())
 401                 }
 402         }
 403
 404         pub(super) fn send_payment<R: Deref, ES: Deref, NS: Deref, F, L: Deref>(
 405                 &self, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>, payment_id: PaymentId,
 406                 retry_strategy: Retry, route_params: RouteParameters, router: &R,
 407                 first_hops: Vec<ChannelDetails>, inflight_htlcs: InFlightHtlcs, entropy_source: &ES,
 408                 node_signer: &NS, best_block_height: u32, logger: &L, send_payment_along_path: F,
 409         ) -> Result<(), PaymentSendFailure>
 410         where
 411                 R::Target: Router,
 412                 ES::Target: EntropySource,
 413                 NS::Target: NodeSigner,
 414                 L::Target: Logger,
 415                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 416                          u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>,
 417         {
 418                 self.pay_internal(payment_id, Some((payment_hash, payment_secret, retry_strategy)),
 419                         route_params, router, first_hops, inflight_htlcs, entropy_source, node_signer,
 420                         best_block_height, logger, &send_payment_along_path)
 421                         .map_err(|e| { self.remove_outbound_if_all_failed(payment_id, &e); e })
 422         }
 423
 424         pub(super) fn send_payment_with_route<ES: Deref, NS: Deref, F>(
 425                 &self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>,
 426                 payment_id: PaymentId, entropy_source: &ES, node_signer: &NS, best_block_height: u32,
 427                 send_payment_along_path: F
 428         ) -> Result<(), PaymentSendFailure>
 429         where
 430                 ES::Target: EntropySource,
 431                 NS::Target: NodeSigner,
 432                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 433                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 434         {
 435                 let onion_session_privs = self.add_new_pending_payment(payment_hash, *payment_secret, payment_id, route, None, None, entropy_source, best_block_height)?;
 436                 self.pay_route_internal(route, payment_hash, payment_secret, None, payment_id, None,
 437                         onion_session_privs, node_signer, best_block_height, &send_payment_along_path)
 438                         .map_err(|e| { self.remove_outbound_if_all_failed(payment_id, &e); e })
 439         }
 440
 441         pub(super) fn send_spontaneous_payment<ES: Deref, NS: Deref, F>(
 442                 &self, route: &Route, payment_preimage: Option<PaymentPreimage>, payment_id: PaymentId,
 443                 entropy_source: &ES, node_signer: &NS, best_block_height: u32, send_payment_along_path: F
 444         ) -> Result<PaymentHash, PaymentSendFailure>
 445         where
 446                 ES::Target: EntropySource,
 447                 NS::Target: NodeSigner,
 448                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 449                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 450         {
 451                 let preimage = match payment_preimage {
 452                         Some(p) => p,
 453                         None => PaymentPreimage(entropy_source.get_secure_random_bytes()),
 454                 };
 455                 let payment_hash = PaymentHash(Sha256::hash(&preimage.0).into_inner());
 456                 let onion_session_privs = self.add_new_pending_payment(payment_hash, None, payment_id, &route, None, None, entropy_source, best_block_height)?;
 457
 458                 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) {
 459                         Ok(()) => Ok(payment_hash),
 460                         Err(e) => {
 461                                 self.remove_outbound_if_all_failed(payment_id, &e);
 462                                 Err(e)
 463                         }
 464                 }
 465         }
 466
 467         pub(super) fn check_retry_payments<R: Deref, ES: Deref, NS: Deref, SP, IH, FH, L: Deref>(
 468                 &self, router: &R, first_hops: FH, inflight_htlcs: IH, entropy_source: &ES, node_signer: &NS,
 469                 best_block_height: u32, logger: &L, send_payment_along_path: SP,
 470         )
 471         where
 472                 R::Target: Router,
 473                 ES::Target: EntropySource,
 474                 NS::Target: NodeSigner,
 475                 SP: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 476                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>,
 477                 IH: Fn() -> InFlightHtlcs,
 478                 FH: Fn() -> Vec<ChannelDetails>,
 479                 L::Target: Logger,
 480         {
 481                 loop {
 482                         let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 483                         let mut retry_id_route_params = None;
 484                         for (pmt_id, pmt) in outbounds.iter_mut() {
 485                                 if pmt.is_auto_retryable_now() {
 486                                         if let PendingOutboundPayment::Retryable { pending_amt_msat, total_msat, payment_params: Some(params), .. } = pmt {
 487                                                 if pending_amt_msat < total_msat {
 488                                                         retry_id_route_params = Some((*pmt_id, RouteParameters {
 489                                                                 final_value_msat: *total_msat - *pending_amt_msat,
 490                                                                 final_cltv_expiry_delta:
 491                                                                         if let Some(delta) = params.final_cltv_expiry_delta { delta }
 492                                                                         else {
 493                                                                                 debug_assert!(false, "We always set the final_cltv_expiry_delta when a path fails");
 494                                                                                 LDK_DEFAULT_MIN_FINAL_CLTV_EXPIRY_DELTA.into()
 495                                                                         },
 496                                                                 payment_params: params.clone(),
 497                                                         }));
 498                                                         break
 499                                                 }
 500                                         }
 501                                 }
 502                         }
 503                         if let Some((payment_id, route_params)) = retry_id_route_params {
 504                                 core::mem::drop(outbounds);
 505                                 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) {
 506                                         log_info!(logger, "Errored retrying payment: {:?}", e);
 507                                 }
 508                         } else { break }
 509                 }
 510         }
 511
 512         fn pay_internal<R: Deref, NS: Deref, ES: Deref, F, L: Deref>(
 513                 &self, payment_id: PaymentId,
 514                 initial_send_info: Option<(PaymentHash, &Option<PaymentSecret>, Retry)>,
 515                 route_params: RouteParameters, router: &R, first_hops: Vec<ChannelDetails>,
 516                 inflight_htlcs: InFlightHtlcs, entropy_source: &ES, node_signer: &NS, best_block_height: u32,
 517                 logger: &L, send_payment_along_path: &F,
 518         ) -> Result<(), PaymentSendFailure>
 519         where
 520                 R::Target: Router,
 521                 ES::Target: EntropySource,
 522                 NS::Target: NodeSigner,
 523                 L::Target: Logger,
 524                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 525                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 526         {
 527                 #[cfg(feature = "std")] {
 528                         if has_expired(&route_params) {
 529                                 return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 530                                         err: format!("Invoice expired for payment id {}", log_bytes!(payment_id.0)),
 531                                 }))
 532                         }
 533                 }
 534
 535                 let route = router.find_route(
 536                         &node_signer.get_node_id(Recipient::Node).unwrap(), &route_params,
 537                         Some(&first_hops.iter().collect::<Vec<_>>()), &inflight_htlcs
 538                 ).map_err(|e| PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 539                         err: format!("Failed to find a route for payment {}: {:?}", log_bytes!(payment_id.0), e), // TODO: add APIError::RouteNotFound
 540                 }))?;
 541
 542                 let res = if let Some((payment_hash, payment_secret, retry_strategy)) = initial_send_info {
 543                         let onion_session_privs = self.add_new_pending_payment(payment_hash, *payment_secret, payment_id, &route, Some(retry_strategy), Some(route_params.payment_params.clone()), entropy_source, best_block_height)?;
 544                         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)
 545                 } else {
 546                         self.retry_payment_with_route(&route, payment_id, entropy_source, node_signer, best_block_height, send_payment_along_path)
 547                 };
 548                 match res {
 549                         Err(PaymentSendFailure::AllFailedResendSafe(_)) => {
 550                                 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);
 551                                 log_info!(logger, "Result retrying payment id {}: {:?}", log_bytes!(payment_id.0), retry_res);
 552                                 if let Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError { err })) = &retry_res {
 553                                         if err.starts_with("Retries exhausted ") { return res; }
 554                                 }
 555                                 retry_res
 556                         },
 557                         Err(PaymentSendFailure::PartialFailure { failed_paths_retry: Some(retry), .. }) => {
 558                                 // Some paths were sent, even if we failed to send the full MPP value our recipient may
 559                                 // misbehave and claim the funds, at which point we have to consider the payment sent, so
 560                                 // return `Ok()` here, ignoring any retry errors.
 561                                 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);
 562                                 log_info!(logger, "Result retrying payment id {}: {:?}", log_bytes!(payment_id.0), retry_res);
 563                                 Ok(())
 564                         },
 565                         Err(PaymentSendFailure::PartialFailure { failed_paths_retry: None, .. }) => {
 566                                 // This may happen if we send a payment and some paths fail, but only due to a temporary
 567                                 // monitor failure or the like, implying they're really in-flight, but we haven't sent the
 568                                 // initial HTLC-Add messages yet.
 569                                 Ok(())
 570                         },
 571                         res => res,
 572                 }
 573         }
 574
 575         pub(super) fn retry_payment_with_route<ES: Deref, NS: Deref, F>(
 576                 &self, route: &Route, payment_id: PaymentId, entropy_source: &ES, node_signer: &NS, best_block_height: u32,
 577                 send_payment_along_path: F
 578         ) -> Result<(), PaymentSendFailure>
 579         where
 580                 ES::Target: EntropySource,
 581                 NS::Target: NodeSigner,
 582                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 583                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 584         {
 585                 const RETRY_OVERFLOW_PERCENTAGE: u64 = 10;
 586                 for path in route.paths.iter() {
 587                         if path.len() == 0 {
 588                                 return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 589                                         err: "length-0 path in route".to_string()
 590                                 }))
 591                         }
 592                 }
 593
 594                 let mut onion_session_privs = Vec::with_capacity(route.paths.len());
 595                 for _ in 0..route.paths.len() {
 596                         onion_session_privs.push(entropy_source.get_secure_random_bytes());
 597                 }
 598
 599                 let (total_msat, payment_hash, payment_secret) = {
 600                         let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 601                         match outbounds.get_mut(&payment_id) {
 602                                 Some(payment) => {
 603                                         let res = match payment {
 604                                                 PendingOutboundPayment::Retryable {
 605                                                         total_msat, payment_hash, payment_secret, pending_amt_msat, ..
 606                                                 } => {
 607                                                         let retry_amt_msat: u64 = route.paths.iter().map(|path| path.last().unwrap().fee_msat).sum();
 608                                                         if retry_amt_msat + *pending_amt_msat > *total_msat * (100 + RETRY_OVERFLOW_PERCENTAGE) / 100 {
 609                                                                 return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 610                                                                         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()
 611                                                                 }))
 612                                                         }
 613                                                         (*total_msat, *payment_hash, *payment_secret)
 614                                                 },
 615                                                 PendingOutboundPayment::Legacy { .. } => {
 616                                                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 617                                                                 err: "Unable to retry payments that were initially sent on LDK versions prior to 0.0.102".to_string()
 618                                                         }))
 619                                                 },
 620                                                 PendingOutboundPayment::Fulfilled { .. } => {
 621                                                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 622                                                                 err: "Payment already completed".to_owned()
 623                                                         }));
 624                                                 },
 625                                                 PendingOutboundPayment::Abandoned { .. } => {
 626                                                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 627                                                                 err: "Payment already abandoned (with some HTLCs still pending)".to_owned()
 628                                                         }));
 629                                                 },
 630                                         };
 631                                         if !payment.is_retryable_now() {
 632                                                 return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 633                                                         err: format!("Retries exhausted for payment id {}", log_bytes!(payment_id.0)),
 634                                                 }))
 635                                         }
 636                                         payment.increment_attempts();
 637                                         for (path, session_priv_bytes) in route.paths.iter().zip(onion_session_privs.iter()) {
 638                                                 assert!(payment.insert(*session_priv_bytes, path));
 639                                         }
 640                                         res
 641                                 },
 642                                 None =>
 643                                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 644                                                 err: format!("Payment with ID {} not found", log_bytes!(payment_id.0)),
 645                                         })),
 646                         }
 647                 };
 648                 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)
 649         }
 650
 651         pub(super) fn send_probe<ES: Deref, NS: Deref, F>(
 652                 &self, hops: Vec<RouteHop>, probing_cookie_secret: [u8; 32], entropy_source: &ES,
 653                 node_signer: &NS, best_block_height: u32, send_payment_along_path: F
 654         ) -> Result<(PaymentHash, PaymentId), PaymentSendFailure>
 655         where
 656                 ES::Target: EntropySource,
 657                 NS::Target: NodeSigner,
 658                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 659                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 660         {
 661                 let payment_id = PaymentId(entropy_source.get_secure_random_bytes());
 662
 663                 let payment_hash = probing_cookie_from_id(&payment_id, probing_cookie_secret);
 664
 665                 if hops.len() < 2 {
 666                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
 667                                 err: "No need probing a path with less than two hops".to_string()
 668                         }))
 669                 }
 670
 671                 let route = Route { paths: vec![hops], payment_params: None };
 672                 let onion_session_privs = self.add_new_pending_payment(payment_hash, None, payment_id, &route, None, None, entropy_source, best_block_height)?;
 673
 674                 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) {
 675                         Ok(()) => Ok((payment_hash, payment_id)),
 676                         Err(e) => {
 677                                 self.remove_outbound_if_all_failed(payment_id, &e);
 678                                 Err(e)
 679                         }
 680                 }
 681         }
 682
 683         #[cfg(test)]
 684         pub(super) fn test_add_new_pending_payment<ES: Deref>(
 685                 &self, payment_hash: PaymentHash, payment_secret: Option<PaymentSecret>, payment_id: PaymentId,
 686                 route: &Route, retry_strategy: Option<Retry>, entropy_source: &ES, best_block_height: u32
 687         ) -> Result<Vec<[u8; 32]>, PaymentSendFailure> where ES::Target: EntropySource {
 688                 self.add_new_pending_payment(payment_hash, payment_secret, payment_id, route, retry_strategy, None, entropy_source, best_block_height)
 689         }
 690
 691         pub(super) fn add_new_pending_payment<ES: Deref>(
 692                 &self, payment_hash: PaymentHash, payment_secret: Option<PaymentSecret>, payment_id: PaymentId,
 693                 route: &Route, retry_strategy: Option<Retry>, payment_params: Option<PaymentParameters>,
 694                 entropy_source: &ES, best_block_height: u32
 695         ) -> Result<Vec<[u8; 32]>, PaymentSendFailure> where ES::Target: EntropySource {
 696                 let mut onion_session_privs = Vec::with_capacity(route.paths.len());
 697                 for _ in 0..route.paths.len() {
 698                         onion_session_privs.push(entropy_source.get_secure_random_bytes());
 699                 }
 700
 701                 let mut pending_outbounds = self.pending_outbound_payments.lock().unwrap();
 702                 match pending_outbounds.entry(payment_id) {
 703                         hash_map::Entry::Occupied(_) => Err(PaymentSendFailure::DuplicatePayment),
 704                         hash_map::Entry::Vacant(entry) => {
 705                                 let payment = entry.insert(PendingOutboundPayment::Retryable {
 706                                         retry_strategy,
 707                                         attempts: PaymentAttempts::new(),
 708                                         payment_params,
 709                                         session_privs: HashSet::new(),
 710                                         pending_amt_msat: 0,
 711                                         pending_fee_msat: Some(0),
 712                                         payment_hash,
 713                                         payment_secret,
 714                                         starting_block_height: best_block_height,
 715                                         total_msat: route.get_total_amount(),
 716                                 });
 717
 718                                 for (path, session_priv_bytes) in route.paths.iter().zip(onion_session_privs.iter()) {
 719                                         assert!(payment.insert(*session_priv_bytes, path));
 720                                 }
 721
 722                                 Ok(onion_session_privs)
 723                         },
 724                 }
 725         }
 726
 727         fn pay_route_internal<NS: Deref, F>(
 728                 &self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>,
 729                 keysend_preimage: Option<PaymentPreimage>, payment_id: PaymentId, recv_value_msat: Option<u64>,
 730                 onion_session_privs: Vec<[u8; 32]>, node_signer: &NS, best_block_height: u32,
 731                 send_payment_along_path: &F
 732         ) -> Result<(), PaymentSendFailure>
 733         where
 734                 NS::Target: NodeSigner,
 735                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 736                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 737         {
 738                 if route.paths.len() < 1 {
 739                         return Err(PaymentSendFailure::ParameterError(APIError::InvalidRoute{err: "There must be at least one path to send over"}));
 740                 }
 741                 if payment_secret.is_none() && route.paths.len() > 1 {
 742                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError{err: "Payment secret is required for multi-path payments".to_string()}));
 743                 }
 744                 let mut total_value = 0;
 745                 let our_node_id = node_signer.get_node_id(Recipient::Node).unwrap(); // TODO no unwrap
 746                 let mut path_errs = Vec::with_capacity(route.paths.len());
 747                 'path_check: for path in route.paths.iter() {
 748                         if path.len() < 1 || path.len() > 20 {
 749                                 path_errs.push(Err(APIError::InvalidRoute{err: "Path didn't go anywhere/had bogus size"}));
 750                                 continue 'path_check;
 751                         }
 752                         for (idx, hop) in path.iter().enumerate() {
 753                                 if idx != path.len() - 1 && hop.pubkey == our_node_id {
 754                                         path_errs.push(Err(APIError::InvalidRoute{err: "Path went through us but wasn't a simple rebalance loop to us"}));
 755                                         continue 'path_check;
 756                                 }
 757                         }
 758                         total_value += path.last().unwrap().fee_msat;
 759                         path_errs.push(Ok(()));
 760                 }
 761                 if path_errs.iter().any(|e| e.is_err()) {
 762                         return Err(PaymentSendFailure::PathParameterError(path_errs));
 763                 }
 764                 if let Some(amt_msat) = recv_value_msat {
 765                         debug_assert!(amt_msat >= total_value);
 766                         total_value = amt_msat;
 767                 }
 768
 769                 let cur_height = best_block_height + 1;
 770                 let mut results = Vec::new();
 771                 debug_assert_eq!(route.paths.len(), onion_session_privs.len());
 772                 for (path, session_priv) in route.paths.iter().zip(onion_session_privs.into_iter()) {
 773                         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);
 774                         match path_res {
 775                                 Ok(_) => {},
 776                                 Err(APIError::MonitorUpdateInProgress) => {
 777                                         // While a MonitorUpdateInProgress is an Err(_), the payment is still
 778                                         // considered "in flight" and we shouldn't remove it from the
 779                                         // PendingOutboundPayment set.
 780                                 },
 781                                 Err(_) => {
 782                                         let mut pending_outbounds = self.pending_outbound_payments.lock().unwrap();
 783                                         if let Some(payment) = pending_outbounds.get_mut(&payment_id) {
 784                                                 let removed = payment.remove(&session_priv, Some(path));
 785                                                 debug_assert!(removed, "This can't happen as the payment has an entry for this path added by callers");
 786                                         } else {
 787                                                 debug_assert!(false, "This can't happen as the payment was added by callers");
 788                                                 path_res = Err(APIError::APIMisuseError { err: "Internal error: payment disappeared during processing. Please report this bug!".to_owned() });
 789                                         }
 790                                 }
 791                         }
 792                         results.push(path_res);
 793                 }
 794                 let mut has_ok = false;
 795                 let mut has_err = false;
 796                 let mut pending_amt_unsent = 0;
 797                 let mut max_unsent_cltv_delta = 0;
 798                 for (res, path) in results.iter().zip(route.paths.iter()) {
 799                         if res.is_ok() { has_ok = true; }
 800                         if res.is_err() { has_err = true; }
 801                         if let &Err(APIError::MonitorUpdateInProgress) = res {
 802                                 // MonitorUpdateInProgress is inherently unsafe to retry, so we call it a
 803                                 // PartialFailure.
 804                                 has_err = true;
 805                                 has_ok = true;
 806                         } else if res.is_err() {
 807                                 pending_amt_unsent += path.last().unwrap().fee_msat;
 808                                 max_unsent_cltv_delta = cmp::max(max_unsent_cltv_delta, path.last().unwrap().cltv_expiry_delta);
 809                         }
 810                 }
 811                 if has_err && has_ok {
 812                         Err(PaymentSendFailure::PartialFailure {
 813                                 results,
 814                                 payment_id,
 815                                 failed_paths_retry: if pending_amt_unsent != 0 {
 816                                         if let Some(payment_params) = &route.payment_params {
 817                                                 Some(RouteParameters {
 818                                                         payment_params: payment_params.clone(),
 819                                                         final_value_msat: pending_amt_unsent,
 820                                                         final_cltv_expiry_delta:
 821                                                                 if let Some(delta) = payment_params.final_cltv_expiry_delta { delta }
 822                                                                 else { max_unsent_cltv_delta },
 823                                                 })
 824                                         } else { None }
 825                                 } else { None },
 826                         })
 827                 } else if has_err {
 828                         Err(PaymentSendFailure::AllFailedResendSafe(results.drain(..).map(|r| r.unwrap_err()).collect()))
 829                 } else {
 830                         Ok(())
 831                 }
 832         }
 833
 834         #[cfg(test)]
 835         pub(super) fn test_send_payment_internal<NS: Deref, F>(
 836                 &self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>,
 837                 keysend_preimage: Option<PaymentPreimage>, payment_id: PaymentId, recv_value_msat: Option<u64>,
 838                 onion_session_privs: Vec<[u8; 32]>, node_signer: &NS, best_block_height: u32,
 839                 send_payment_along_path: F
 840         ) -> Result<(), PaymentSendFailure>
 841         where
 842                 NS::Target: NodeSigner,
 843                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
 844                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
 845         {
 846                 self.pay_route_internal(route, payment_hash, payment_secret, keysend_preimage, payment_id,
 847                         recv_value_msat, onion_session_privs, node_signer, best_block_height,
 848                         &send_payment_along_path)
 849                         .map_err(|e| { self.remove_outbound_if_all_failed(payment_id, &e); e })
 850         }
 851
 852         // If we failed to send any paths, we should remove the new PaymentId from the
 853         // `pending_outbound_payments` map, as the user isn't expected to `abandon_payment`.
 854         fn remove_outbound_if_all_failed(&self, payment_id: PaymentId, err: &PaymentSendFailure) {
 855                 if let &PaymentSendFailure::AllFailedResendSafe(_) = err {
 856                         let removed = self.pending_outbound_payments.lock().unwrap().remove(&payment_id).is_some();
 857                         debug_assert!(removed, "We should always have a pending payment to remove here");
 858                 }
 859         }
 860
 861         pub(super) fn claim_htlc<L: Deref>(
 862                 &self, payment_id: PaymentId, payment_preimage: PaymentPreimage, session_priv: SecretKey,
 863                 path: Vec<RouteHop>, from_onchain: bool, pending_events: &Mutex<Vec<events::Event>>, logger: &L
 864         ) where L::Target: Logger {
 865                 let mut session_priv_bytes = [0; 32];
 866                 session_priv_bytes.copy_from_slice(&session_priv[..]);
 867                 let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 868                 let mut pending_events = pending_events.lock().unwrap();
 869                 if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(payment_id) {
 870                         if !payment.get().is_fulfilled() {
 871                                 let payment_hash = PaymentHash(Sha256::hash(&payment_preimage.0).into_inner());
 872                                 let fee_paid_msat = payment.get().get_pending_fee_msat();
 873                                 pending_events.push(
 874                                         events::Event::PaymentSent {
 875                                                 payment_id: Some(payment_id),
 876                                                 payment_preimage,
 877                                                 payment_hash,
 878                                                 fee_paid_msat,
 879                                         }
 880                                 );
 881                                 payment.get_mut().mark_fulfilled();
 882                         }
 883
 884                         if from_onchain {
 885                                 // We currently immediately remove HTLCs which were fulfilled on-chain.
 886                                 // This could potentially lead to removing a pending payment too early,
 887                                 // with a reorg of one block causing us to re-add the fulfilled payment on
 888                                 // restart.
 889                                 // TODO: We should have a second monitor event that informs us of payments
 890                                 // irrevocably fulfilled.
 891                                 if payment.get_mut().remove(&session_priv_bytes, Some(&path)) {
 892                                         let payment_hash = Some(PaymentHash(Sha256::hash(&payment_preimage.0).into_inner()));
 893                                         pending_events.push(
 894                                                 events::Event::PaymentPathSuccessful {
 895                                                         payment_id,
 896                                                         payment_hash,
 897                                                         path,
 898                                                 }
 899                                         );
 900                                 }
 901                         }
 902                 } else {
 903                         log_trace!(logger, "Received duplicative fulfill for HTLC with payment_preimage {}", log_bytes!(payment_preimage.0));
 904                 }
 905         }
 906
 907         pub(super) fn finalize_claims(&self, sources: Vec<HTLCSource>, pending_events: &Mutex<Vec<events::Event>>) {
 908                 let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 909                 let mut pending_events = pending_events.lock().unwrap();
 910                 for source in sources {
 911                         if let HTLCSource::OutboundRoute { session_priv, payment_id, path, .. } = source {
 912                                 let mut session_priv_bytes = [0; 32];
 913                                 session_priv_bytes.copy_from_slice(&session_priv[..]);
 914                                 if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(payment_id) {
 915                                         assert!(payment.get().is_fulfilled());
 916                                         if payment.get_mut().remove(&session_priv_bytes, None) {
 917                                                 pending_events.push(
 918                                                         events::Event::PaymentPathSuccessful {
 919                                                                 payment_id,
 920                                                                 payment_hash: payment.get().payment_hash(),
 921                                                                 path,
 922                                                         }
 923                                                 );
 924                                         }
 925                                 }
 926                         }
 927                 }
 928         }
 929
 930         pub(super) fn remove_stale_resolved_payments(&self, pending_events: &Mutex<Vec<events::Event>>) {
 931                 // If an outbound payment was completed, and no pending HTLCs remain, we should remove it
 932                 // from the map. However, if we did that immediately when the last payment HTLC is claimed,
 933                 // this could race the user making a duplicate send_payment call and our idempotency
 934                 // guarantees would be violated. Instead, we wait a few timer ticks to do the actual
 935                 // removal. This should be more than sufficient to ensure the idempotency of any
 936                 // `send_payment` calls that were made at the same time the `PaymentSent` event was being
 937                 // processed.
 938                 let mut pending_outbound_payments = self.pending_outbound_payments.lock().unwrap();
 939                 let pending_events = pending_events.lock().unwrap();
 940                 pending_outbound_payments.retain(|payment_id, payment| {
 941                         if let PendingOutboundPayment::Fulfilled { session_privs, timer_ticks_without_htlcs, .. } = payment {
 942                                 let mut no_remaining_entries = session_privs.is_empty();
 943                                 if no_remaining_entries {
 944                                         for ev in pending_events.iter() {
 945                                                 match ev {
 946                                                         events::Event::PaymentSent { payment_id: Some(ev_payment_id), .. } |
 947                                                                 events::Event::PaymentPathSuccessful { payment_id: ev_payment_id, .. } |
 948                                                                 events::Event::PaymentPathFailed { payment_id: Some(ev_payment_id), .. } => {
 949                                                                         if payment_id == ev_payment_id {
 950                                                                                 no_remaining_entries = false;
 951                                                                                 break;
 952                                                                         }
 953                                                                 },
 954                                                         _ => {},
 955                                                 }
 956                                         }
 957                                 }
 958                                 if no_remaining_entries {
 959                                         *timer_ticks_without_htlcs += 1;
 960                                         *timer_ticks_without_htlcs <= IDEMPOTENCY_TIMEOUT_TICKS
 961                                 } else {
 962                                         *timer_ticks_without_htlcs = 0;
 963                                         true
 964                                 }
 965                         } else { true }
 966                 });
 967         }
 968
 969         pub(super) fn fail_htlc<L: Deref>(
 970                 &self, source: &HTLCSource, payment_hash: &PaymentHash, onion_error: &HTLCFailReason,
 971                 path: &Vec<RouteHop>, session_priv: &SecretKey, payment_id: &PaymentId,
 972                 payment_params: &Option<PaymentParameters>, probing_cookie_secret: [u8; 32],
 973                 secp_ctx: &Secp256k1<secp256k1::All>, pending_events: &Mutex<Vec<events::Event>>, logger: &L
 974         ) where L::Target: Logger {
 975                 #[cfg(test)]
 976                 let (network_update, short_channel_id, payment_retryable, onion_error_code, onion_error_data) = onion_error.decode_onion_failure(secp_ctx, logger, &source);
 977                 #[cfg(not(test))]
 978                 let (network_update, short_channel_id, payment_retryable, _, _) = onion_error.decode_onion_failure(secp_ctx, logger, &source);
 979
 980                 let mut session_priv_bytes = [0; 32];
 981                 session_priv_bytes.copy_from_slice(&session_priv[..]);
 982                 let mut outbounds = self.pending_outbound_payments.lock().unwrap();
 983                 let mut all_paths_failed = false;
 984                 let mut full_failure_ev = None;
 985                 let mut pending_retry_ev = None;
 986                 let mut retry = None;
 987                 let attempts_remaining = if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(*payment_id) {
 988                         if !payment.get_mut().remove(&session_priv_bytes, Some(&path)) {
 989                                 log_trace!(logger, "Received duplicative fail for HTLC with payment_hash {}", log_bytes!(payment_hash.0));
 990                                 return
 991                         }
 992                         if payment.get().is_fulfilled() {
 993                                 log_trace!(logger, "Received failure of HTLC with payment_hash {} after payment completion", log_bytes!(payment_hash.0));
 994                                 return
 995                         }
 996                         let is_retryable_now = payment.get().is_auto_retryable_now();
 997                         if let Some(scid) = short_channel_id {
 998                                 payment.get_mut().insert_previously_failed_scid(scid);
 999                         }
1000
1001                         // We want to move towards only using the `PaymentParameters` in the outbound payments
1002                         // map. However, for backwards-compatibility, we still need to support passing the
1003                         // `PaymentParameters` data that was shoved in the HTLC (and given to us via
1004                         // `payment_params`) back to the user.
1005                         let path_last_hop = path.last().expect("Outbound payments must have had a valid path");
1006                         if let Some(params) = payment.get_mut().payment_parameters() {
1007                                 if params.final_cltv_expiry_delta.is_none() {
1008                                         // This should be rare, but a user could provide None for the payment data, and
1009                                         // we need it when we go to retry the payment, so fill it in.
1010                                         params.final_cltv_expiry_delta = Some(path_last_hop.cltv_expiry_delta);
1011                                 }
1012                                 retry = Some(RouteParameters {
1013                                         payment_params: params.clone(),
1014                                         final_value_msat: path_last_hop.fee_msat,
1015                                         final_cltv_expiry_delta: params.final_cltv_expiry_delta.unwrap(),
1016                                 });
1017                         } else if let Some(params) = payment_params {
1018                                 retry = Some(RouteParameters {
1019                                         payment_params: params.clone(),
1020                                         final_value_msat: path_last_hop.fee_msat,
1021                                         final_cltv_expiry_delta:
1022                                                 if let Some(delta) = params.final_cltv_expiry_delta { delta }
1023                                                 else { path_last_hop.cltv_expiry_delta },
1024                                 });
1025                         }
1026
1027                         if payment.get().remaining_parts() == 0 {
1028                                 all_paths_failed = true;
1029                                 if payment.get().abandoned() {
1030                                         full_failure_ev = Some(events::Event::PaymentFailed {
1031                                                 payment_id: *payment_id,
1032                                                 payment_hash: payment.get().payment_hash().expect("PendingOutboundPayments::RetriesExceeded always has a payment hash set"),
1033                                         });
1034                                         payment.remove();
1035                                 }
1036                         }
1037                         is_retryable_now
1038                 } else {
1039                         log_trace!(logger, "Received duplicative fail for HTLC with payment_hash {}", log_bytes!(payment_hash.0));
1040                         return
1041                 };
1042                 core::mem::drop(outbounds);
1043                 log_trace!(logger, "Failing outbound payment HTLC with payment_hash {}", log_bytes!(payment_hash.0));
1044
1045                 let path_failure = {
1046                         if payment_is_probe(payment_hash, &payment_id, probing_cookie_secret) {
1047                                 if !payment_retryable {
1048                                         events::Event::ProbeSuccessful {
1049                                                 payment_id: *payment_id,
1050                                                 payment_hash: payment_hash.clone(),
1051                                                 path: path.clone(),
1052                                         }
1053                                 } else {
1054                                         events::Event::ProbeFailed {
1055                                                 payment_id: *payment_id,
1056                                                 payment_hash: payment_hash.clone(),
1057                                                 path: path.clone(),
1058                                                 short_channel_id,
1059                                         }
1060                                 }
1061                         } else {
1062                                 // TODO: If we decided to blame ourselves (or one of our channels) in
1063                                 // process_onion_failure we should close that channel as it implies our
1064                                 // next-hop is needlessly blaming us!
1065                                 if let Some(scid) = short_channel_id {
1066                                         retry.as_mut().map(|r| r.payment_params.previously_failed_channels.push(scid));
1067                                 }
1068                                 if payment_retryable && attempts_remaining && retry.is_some() {
1069                                         debug_assert!(full_failure_ev.is_none());
1070                                         pending_retry_ev = Some(events::Event::PendingHTLCsForwardable {
1071                                                 time_forwardable: Duration::from_millis(MIN_HTLC_RELAY_HOLDING_CELL_MILLIS),
1072                                         });
1073                                 }
1074                                 events::Event::PaymentPathFailed {
1075                                         payment_id: Some(*payment_id),
1076                                         payment_hash: payment_hash.clone(),
1077                                         payment_failed_permanently: !payment_retryable,
1078                                         network_update,
1079                                         all_paths_failed,
1080                                         path: path.clone(),
1081                                         short_channel_id,
1082                                         retry,
1083                                         #[cfg(test)]
1084                                         error_code: onion_error_code,
1085                                         #[cfg(test)]
1086                                         error_data: onion_error_data
1087                                 }
1088                         }
1089                 };
1090                 let mut pending_events = pending_events.lock().unwrap();
1091                 pending_events.push(path_failure);
1092                 if let Some(ev) = full_failure_ev { pending_events.push(ev); }
1093                 if let Some(ev) = pending_retry_ev { pending_events.push(ev); }
1094         }
1095
1096         pub(super) fn abandon_payment(&self, payment_id: PaymentId) -> Option<events::Event> {
1097                 let mut failed_ev = None;
1098                 let mut outbounds = self.pending_outbound_payments.lock().unwrap();
1099                 if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(payment_id) {
1100                         if let Ok(()) = payment.get_mut().mark_abandoned() {
1101                                 if payment.get().remaining_parts() == 0 {
1102                                         failed_ev = Some(events::Event::PaymentFailed {
1103                                                 payment_id,
1104                                                 payment_hash: payment.get().payment_hash().expect("PendingOutboundPayments::RetriesExceeded always has a payment hash set"),
1105                                         });
1106                                         payment.remove();
1107                                 }
1108                         }
1109                 }
1110                 failed_ev
1111         }
1112
1113         #[cfg(test)]
1114         pub fn has_pending_payments(&self) -> bool {
1115                 !self.pending_outbound_payments.lock().unwrap().is_empty()
1116         }
1117
1118         #[cfg(test)]
1119         pub fn clear_pending_payments(&self) {
1120                 self.pending_outbound_payments.lock().unwrap().clear()
1121         }
1122 }
1123
1124 /// Returns whether a payment with the given [`PaymentHash`] and [`PaymentId`] is, in fact, a
1125 /// payment probe.
1126 pub(super) fn payment_is_probe(payment_hash: &PaymentHash, payment_id: &PaymentId,
1127         probing_cookie_secret: [u8; 32]) -> bool
1128 {
1129         let target_payment_hash = probing_cookie_from_id(payment_id, probing_cookie_secret);
1130         target_payment_hash == *payment_hash
1131 }
1132
1133 /// Returns the 'probing cookie' for the given [`PaymentId`].
1134 fn probing_cookie_from_id(payment_id: &PaymentId, probing_cookie_secret: [u8; 32]) -> PaymentHash {
1135         let mut preimage = [0u8; 64];
1136         preimage[..32].copy_from_slice(&probing_cookie_secret);
1137         preimage[32..].copy_from_slice(&payment_id.0);
1138         PaymentHash(Sha256::hash(&preimage).into_inner())
1139 }
1140
1141 impl_writeable_tlv_based_enum_upgradable!(PendingOutboundPayment,
1142         (0, Legacy) => {
1143                 (0, session_privs, required),
1144         },
1145         (1, Fulfilled) => {
1146                 (0, session_privs, required),
1147                 (1, payment_hash, option),
1148                 (3, timer_ticks_without_htlcs, (default_value, 0)),
1149         },
1150         (2, Retryable) => {
1151                 (0, session_privs, required),
1152                 (1, pending_fee_msat, option),
1153                 (2, payment_hash, required),
1154                 (3, payment_params, option),
1155                 (4, payment_secret, option),
1156                 (6, total_msat, required),
1157                 (8, pending_amt_msat, required),
1158                 (10, starting_block_height, required),
1159                 (not_written, retry_strategy, (static_value, None)),
1160                 (not_written, attempts, (static_value, PaymentAttempts::new())),
1161         },
1162         (3, Abandoned) => {
1163                 (0, session_privs, required),
1164                 (2, payment_hash, required),
1165         },
1166 );
1167
1168 #[cfg(test)]
1169 mod tests {
1170         use bitcoin::blockdata::constants::genesis_block;
1171         use bitcoin::network::constants::Network;
1172         use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey};
1173
1174         use crate::ln::PaymentHash;
1175         use crate::ln::channelmanager::{PaymentId, PaymentSendFailure};
1176         use crate::ln::msgs::{ErrorAction, LightningError};
1177         use crate::ln::outbound_payment::{OutboundPayments, Retry};
1178         use crate::routing::gossip::NetworkGraph;
1179         use crate::routing::router::{InFlightHtlcs, PaymentParameters, Route, RouteParameters};
1180         use crate::sync::Arc;
1181         use crate::util::errors::APIError;
1182         use crate::util::test_utils;
1183
1184         #[test]
1185         #[cfg(feature = "std")]
1186         fn fails_paying_after_expiration() {
1187                 do_fails_paying_after_expiration(false);
1188                 do_fails_paying_after_expiration(true);
1189         }
1190         #[cfg(feature = "std")]
1191         fn do_fails_paying_after_expiration(on_retry: bool) {
1192                 let outbound_payments = OutboundPayments::new();
1193                 let logger = test_utils::TestLogger::new();
1194                 let genesis_hash = genesis_block(Network::Testnet).header.block_hash();
1195                 let network_graph = Arc::new(NetworkGraph::new(genesis_hash, &logger));
1196                 let router = test_utils::TestRouter::new(network_graph);
1197                 let secp_ctx = Secp256k1::new();
1198                 let keys_manager = test_utils::TestKeysInterface::new(&[0; 32], Network::Testnet);
1199
1200                 let past_expiry_time = std::time::SystemTime::UNIX_EPOCH.elapsed().unwrap().as_secs() - 2;
1201                 let payment_params = PaymentParameters::from_node_id(
1202                                 PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap()),
1203                                 0
1204                         ).with_expiry_time(past_expiry_time);
1205                 let expired_route_params = RouteParameters {
1206                         payment_params,
1207                         final_value_msat: 0,
1208                         final_cltv_expiry_delta: 0,
1209                 };
1210                 let err = if on_retry {
1211                         outbound_payments.pay_internal(
1212                                 PaymentId([0; 32]), None, expired_route_params, &&router, vec![], InFlightHtlcs::new(),
1213                                 &&keys_manager, &&keys_manager, 0, &&logger, &|_, _, _, _, _, _, _, _, _| Ok(())).unwrap_err()
1214                 } else {
1215                         outbound_payments.send_payment(
1216                                 PaymentHash([0; 32]), &None, PaymentId([0; 32]), Retry::Attempts(0), expired_route_params,
1217                                 &&router, vec![], InFlightHtlcs::new(), &&keys_manager, &&keys_manager, 0, &&logger,
1218                                 |_, _, _, _, _, _, _, _, _| Ok(())).unwrap_err()
1219                 };
1220                 if let PaymentSendFailure::ParameterError(APIError::APIMisuseError { err }) = err {
1221                         assert!(err.contains("Invoice expired"));
1222                 } else { panic!("Unexpected error"); }
1223         }
1224
1225         #[test]
1226         fn find_route_error() {
1227                 do_find_route_error(false);
1228                 do_find_route_error(true);
1229         }
1230         fn do_find_route_error(on_retry: bool) {
1231                 let outbound_payments = OutboundPayments::new();
1232                 let logger = test_utils::TestLogger::new();
1233                 let genesis_hash = genesis_block(Network::Testnet).header.block_hash();
1234                 let network_graph = Arc::new(NetworkGraph::new(genesis_hash, &logger));
1235                 let router = test_utils::TestRouter::new(network_graph);
1236                 let secp_ctx = Secp256k1::new();
1237                 let keys_manager = test_utils::TestKeysInterface::new(&[0; 32], Network::Testnet);
1238
1239                 let payment_params = PaymentParameters::from_node_id(
1240                         PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap()), 0);
1241                 let route_params = RouteParameters {
1242                         payment_params,
1243                         final_value_msat: 0,
1244                         final_cltv_expiry_delta: 0,
1245                 };
1246                 router.expect_find_route(route_params.clone(),
1247                         Err(LightningError { err: String::new(), action: ErrorAction::IgnoreError }));
1248
1249                 let err = if on_retry {
1250                         outbound_payments.add_new_pending_payment(PaymentHash([0; 32]), None, PaymentId([0; 32]),
1251                         &Route { paths: vec![], payment_params: None }, Some(Retry::Attempts(1)), Some(route_params.payment_params.clone()),
1252                         &&keys_manager, 0).unwrap();
1253                         outbound_payments.pay_internal(
1254                                 PaymentId([0; 32]), None, route_params, &&router, vec![], InFlightHtlcs::new(),
1255                                 &&keys_manager, &&keys_manager, 0, &&logger, &|_, _, _, _, _, _, _, _, _| Ok(())).unwrap_err()
1256                 } else {
1257                         outbound_payments.send_payment(
1258                                 PaymentHash([0; 32]), &None, PaymentId([0; 32]), Retry::Attempts(0), route_params,
1259                                 &&router, vec![], InFlightHtlcs::new(), &&keys_manager, &&keys_manager, 0, &&logger,
1260                                 |_, _, _, _, _, _, _, _, _| Ok(())).unwrap_err()
1261                 };
1262                 if let PaymentSendFailure::ParameterError(APIError::APIMisuseError { err }) = err {
1263                         assert!(err.contains("Failed to find a route"));
1264                 } else { panic!("Unexpected error"); }
1265         }
1266 }