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