eacf46892f565b4c1c65dfa551f8622decf8c1c0
[rust-lightning] / 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::{KeysInterface, Recipient};
17 use crate::ln::{PaymentHash, PaymentPreimage, PaymentSecret};
18 use crate::ln::channelmanager::{HTLCSource, IDEMPOTENCY_TIMEOUT_TICKS, 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
26 use core::cmp;
27 use core::ops::Deref;
28 use crate::prelude::*;
29 use crate::sync::Mutex;
30
31 /// Stores the session_priv for each part of a payment that is still pending. For versions 0.0.102
32 /// and later, also stores information for retrying the payment.
33 pub(crate) enum PendingOutboundPayment {
34         Legacy {
35                 session_privs: HashSet<[u8; 32]>,
36         },
37         Retryable {
38                 session_privs: HashSet<[u8; 32]>,
39                 payment_hash: PaymentHash,
40                 payment_secret: Option<PaymentSecret>,
41                 pending_amt_msat: u64,
42                 /// Used to track the fee paid. Only present if the payment was serialized on 0.0.103+.
43                 pending_fee_msat: Option<u64>,
44                 /// The total payment amount across all paths, used to verify that a retry is not overpaying.
45                 total_msat: u64,
46                 /// Our best known block height at the time this payment was initiated.
47                 starting_block_height: u32,
48         },
49         /// When a pending payment is fulfilled, we continue tracking it until all pending HTLCs have
50         /// been resolved. This ensures we don't look up pending payments in ChannelMonitors on restart
51         /// and add a pending payment that was already fulfilled.
52         Fulfilled {
53                 session_privs: HashSet<[u8; 32]>,
54                 payment_hash: Option<PaymentHash>,
55                 timer_ticks_without_htlcs: u8,
56         },
57         /// When a payer gives up trying to retry a payment, they inform us, letting us generate a
58         /// `PaymentFailed` event when all HTLCs have irrevocably failed. This avoids a number of race
59         /// conditions in MPP-aware payment retriers (1), where the possibility of multiple
60         /// `PaymentPathFailed` events with `all_paths_failed` can be pending at once, confusing a
61         /// downstream event handler as to when a payment has actually failed.
62         ///
63         /// (1) https://github.com/lightningdevkit/rust-lightning/issues/1164
64         Abandoned {
65                 session_privs: HashSet<[u8; 32]>,
66                 payment_hash: PaymentHash,
67         },
68 }
69
70 impl PendingOutboundPayment {
71         pub(super) fn is_fulfilled(&self) -> bool {
72                 match self {
73                         PendingOutboundPayment::Fulfilled { .. } => true,
74                         _ => false,
75                 }
76         }
77         pub(super) fn abandoned(&self) -> bool {
78                 match self {
79                         PendingOutboundPayment::Abandoned { .. } => true,
80                         _ => false,
81                 }
82         }
83         pub(super) fn get_pending_fee_msat(&self) -> Option<u64> {
84                 match self {
85                         PendingOutboundPayment::Retryable { pending_fee_msat, .. } => pending_fee_msat.clone(),
86                         _ => None,
87                 }
88         }
89
90         pub(super) fn payment_hash(&self) -> Option<PaymentHash> {
91                 match self {
92                         PendingOutboundPayment::Legacy { .. } => None,
93                         PendingOutboundPayment::Retryable { payment_hash, .. } => Some(*payment_hash),
94                         PendingOutboundPayment::Fulfilled { payment_hash, .. } => *payment_hash,
95                         PendingOutboundPayment::Abandoned { payment_hash, .. } => Some(*payment_hash),
96                 }
97         }
98
99         pub(super) fn mark_fulfilled(&mut self) {
100                 let mut session_privs = HashSet::new();
101                 core::mem::swap(&mut session_privs, match self {
102                         PendingOutboundPayment::Legacy { session_privs } |
103                                 PendingOutboundPayment::Retryable { session_privs, .. } |
104                                 PendingOutboundPayment::Fulfilled { session_privs, .. } |
105                                 PendingOutboundPayment::Abandoned { session_privs, .. }
106                         => session_privs,
107                 });
108                 let payment_hash = self.payment_hash();
109                 *self = PendingOutboundPayment::Fulfilled { session_privs, payment_hash, timer_ticks_without_htlcs: 0 };
110         }
111
112         pub(super) fn mark_abandoned(&mut self) -> Result<(), ()> {
113                 let mut session_privs = HashSet::new();
114                 let our_payment_hash;
115                 core::mem::swap(&mut session_privs, match self {
116                         PendingOutboundPayment::Legacy { .. } |
117                                 PendingOutboundPayment::Fulfilled { .. } =>
118                                 return Err(()),
119                                 PendingOutboundPayment::Retryable { session_privs, payment_hash, .. } |
120                                         PendingOutboundPayment::Abandoned { session_privs, payment_hash, .. } => {
121                                                 our_payment_hash = *payment_hash;
122                                                 session_privs
123                                         },
124                 });
125                 *self = PendingOutboundPayment::Abandoned { session_privs, payment_hash: our_payment_hash };
126                 Ok(())
127         }
128
129         /// panics if path is None and !self.is_fulfilled
130         pub(super) fn remove(&mut self, session_priv: &[u8; 32], path: Option<&Vec<RouteHop>>) -> bool {
131                 let remove_res = match self {
132                         PendingOutboundPayment::Legacy { session_privs } |
133                                 PendingOutboundPayment::Retryable { session_privs, .. } |
134                                 PendingOutboundPayment::Fulfilled { session_privs, .. } |
135                                 PendingOutboundPayment::Abandoned { session_privs, .. } => {
136                                         session_privs.remove(session_priv)
137                                 }
138                 };
139                 if remove_res {
140                         if let PendingOutboundPayment::Retryable { ref mut pending_amt_msat, ref mut pending_fee_msat, .. } = self {
141                                 let path = path.expect("Fulfilling a payment should always come with a path");
142                                 let path_last_hop = path.last().expect("Outbound payments must have had a valid path");
143                                 *pending_amt_msat -= path_last_hop.fee_msat;
144                                 if let Some(fee_msat) = pending_fee_msat.as_mut() {
145                                         *fee_msat -= path.get_path_fees();
146                                 }
147                         }
148                 }
149                 remove_res
150         }
151
152         pub(super) fn insert(&mut self, session_priv: [u8; 32], path: &Vec<RouteHop>) -> bool {
153                 let insert_res = match self {
154                         PendingOutboundPayment::Legacy { session_privs } |
155                                 PendingOutboundPayment::Retryable { session_privs, .. } => {
156                                         session_privs.insert(session_priv)
157                                 }
158                         PendingOutboundPayment::Fulfilled { .. } => false,
159                         PendingOutboundPayment::Abandoned { .. } => false,
160                 };
161                 if insert_res {
162                         if let PendingOutboundPayment::Retryable { ref mut pending_amt_msat, ref mut pending_fee_msat, .. } = self {
163                                 let path_last_hop = path.last().expect("Outbound payments must have had a valid path");
164                                 *pending_amt_msat += path_last_hop.fee_msat;
165                                 if let Some(fee_msat) = pending_fee_msat.as_mut() {
166                                         *fee_msat += path.get_path_fees();
167                                 }
168                         }
169                 }
170                 insert_res
171         }
172
173         pub(super) fn remaining_parts(&self) -> usize {
174                 match self {
175                         PendingOutboundPayment::Legacy { session_privs } |
176                                 PendingOutboundPayment::Retryable { session_privs, .. } |
177                                 PendingOutboundPayment::Fulfilled { session_privs, .. } |
178                                 PendingOutboundPayment::Abandoned { session_privs, .. } => {
179                                         session_privs.len()
180                                 }
181                 }
182         }
183 }
184
185 /// If a payment fails to send, it can be in one of several states. This enum is returned as the
186 /// Err() type describing which state the payment is in, see the description of individual enum
187 /// states for more.
188 #[derive(Clone, Debug)]
189 pub enum PaymentSendFailure {
190         /// A parameter which was passed to send_payment was invalid, preventing us from attempting to
191         /// send the payment at all.
192         ///
193         /// You can freely resend the payment in full (with the parameter error fixed).
194         ///
195         /// Because the payment failed outright, no payment tracking is done, you do not need to call
196         /// [`ChannelManager::abandon_payment`] and [`ChannelManager::retry_payment`] will *not* work
197         /// for this payment.
198         ///
199         /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
200         /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
201         ParameterError(APIError),
202         /// A parameter in a single path which was passed to send_payment was invalid, preventing us
203         /// from attempting to send the payment at all.
204         ///
205         /// You can freely resend the payment in full (with the parameter error fixed).
206         ///
207         /// The results here are ordered the same as the paths in the route object which was passed to
208         /// send_payment.
209         ///
210         /// Because the payment failed outright, no payment tracking is done, you do not need to call
211         /// [`ChannelManager::abandon_payment`] and [`ChannelManager::retry_payment`] will *not* work
212         /// for this payment.
213         ///
214         /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
215         /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
216         PathParameterError(Vec<Result<(), APIError>>),
217         /// All paths which were attempted failed to send, with no channel state change taking place.
218         /// You can freely resend the payment in full (though you probably want to do so over different
219         /// paths than the ones selected).
220         ///
221         /// Because the payment failed outright, no payment tracking is done, you do not need to call
222         /// [`ChannelManager::abandon_payment`] and [`ChannelManager::retry_payment`] will *not* work
223         /// for this payment.
224         ///
225         /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
226         /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
227         AllFailedResendSafe(Vec<APIError>),
228         /// Indicates that a payment for the provided [`PaymentId`] is already in-flight and has not
229         /// yet completed (i.e. generated an [`Event::PaymentSent`]) or been abandoned (via
230         /// [`ChannelManager::abandon_payment`]).
231         ///
232         /// [`PaymentId`]: crate::ln::channelmanager::PaymentId
233         /// [`Event::PaymentSent`]: crate::util::events::Event::PaymentSent
234         /// [`ChannelManager::abandon_payment`]: crate::ln::channelmanager::ChannelManager::abandon_payment
235         DuplicatePayment,
236         /// Some paths which were attempted failed to send, though possibly not all. At least some
237         /// paths have irrevocably committed to the HTLC and retrying the payment in full would result
238         /// in over-/re-payment.
239         ///
240         /// The results here are ordered the same as the paths in the route object which was passed to
241         /// send_payment, and any `Err`s which are not [`APIError::MonitorUpdateInProgress`] can be
242         /// safely retried via [`ChannelManager::retry_payment`].
243         ///
244         /// Any entries which contain `Err(APIError::MonitorUpdateInprogress)` or `Ok(())` MUST NOT be
245         /// retried as they will result in over-/re-payment. These HTLCs all either successfully sent
246         /// (in the case of `Ok(())`) or will send once a [`MonitorEvent::Completed`] is provided for
247         /// the next-hop channel with the latest update_id.
248         ///
249         /// [`ChannelManager::retry_payment`]: crate::ln::channelmanager::ChannelManager::retry_payment
250         /// [`MonitorEvent::Completed`]: crate::chain::channelmonitor::MonitorEvent::Completed
251         PartialFailure {
252                 /// The errors themselves, in the same order as the route hops.
253                 results: Vec<Result<(), APIError>>,
254                 /// If some paths failed without irrevocably committing to the new HTLC(s), this will
255                 /// contain a [`RouteParameters`] object which can be used to calculate a new route that
256                 /// will pay all remaining unpaid balance.
257                 failed_paths_retry: Option<RouteParameters>,
258                 /// The payment id for the payment, which is now at least partially pending.
259                 payment_id: PaymentId,
260         },
261 }
262
263 pub(super) struct OutboundPayments {
264         pub(super) pending_outbound_payments: Mutex<HashMap<PaymentId, PendingOutboundPayment>>,
265 }
266
267 impl OutboundPayments {
268         pub(super) fn new() -> Self {
269                 Self {
270                         pending_outbound_payments: Mutex::new(HashMap::new())
271                 }
272         }
273
274         pub(super) fn send_payment<K: Deref, F>(&self, route: &Route, payment_hash: PaymentHash,
275                 payment_secret: &Option<PaymentSecret>, payment_id: PaymentId, keys_manager: &K,
276                 best_block_height: u32, send_payment_along_path: F)
277         -> Result<(), PaymentSendFailure>
278         where
279                 K::Target: KeysInterface,
280                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
281                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
282         {
283                 let onion_session_privs = self.add_new_pending_payment(payment_hash, *payment_secret, payment_id, route, keys_manager, best_block_height)?;
284                 self.send_payment_internal(route, payment_hash, payment_secret, None, payment_id, None, onion_session_privs, keys_manager, best_block_height, send_payment_along_path)
285         }
286
287         pub(super) fn send_spontaneous_payment<K: Deref, F>(&self, route: &Route,
288                 payment_preimage: Option<PaymentPreimage>, payment_id: PaymentId, keys_manager: &K,
289                 best_block_height: u32, send_payment_along_path: F)
290         -> Result<PaymentHash, PaymentSendFailure>
291         where
292                 K::Target: KeysInterface,
293                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
294                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
295         {
296                 let preimage = match payment_preimage {
297                         Some(p) => p,
298                         None => PaymentPreimage(keys_manager.get_secure_random_bytes()),
299                 };
300                 let payment_hash = PaymentHash(Sha256::hash(&preimage.0).into_inner());
301                 let onion_session_privs = self.add_new_pending_payment(payment_hash, None, payment_id, &route, keys_manager, best_block_height)?;
302
303                 match self.send_payment_internal(route, payment_hash, &None, Some(preimage), payment_id, None, onion_session_privs, keys_manager, best_block_height, send_payment_along_path) {
304                         Ok(()) => Ok(payment_hash),
305                         Err(e) => Err(e)
306                 }
307         }
308
309         pub(super) fn retry_payment<K: Deref, F>(&self, route: &Route, payment_id: PaymentId,
310                 keys_manager: &K, best_block_height: u32, send_payment_along_path: F)
311         -> Result<(), PaymentSendFailure>
312         where
313                 K::Target: KeysInterface,
314                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
315                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
316         {
317                 const RETRY_OVERFLOW_PERCENTAGE: u64 = 10;
318                 for path in route.paths.iter() {
319                         if path.len() == 0 {
320                                 return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
321                                         err: "length-0 path in route".to_string()
322                                 }))
323                         }
324                 }
325
326                 let mut onion_session_privs = Vec::with_capacity(route.paths.len());
327                 for _ in 0..route.paths.len() {
328                         onion_session_privs.push(keys_manager.get_secure_random_bytes());
329                 }
330
331                 let (total_msat, payment_hash, payment_secret) = {
332                         let mut outbounds = self.pending_outbound_payments.lock().unwrap();
333                         match outbounds.get_mut(&payment_id) {
334                                 Some(payment) => {
335                                         let res = match payment {
336                                                 PendingOutboundPayment::Retryable {
337                                                         total_msat, payment_hash, payment_secret, pending_amt_msat, ..
338                                                 } => {
339                                                         let retry_amt_msat: u64 = route.paths.iter().map(|path| path.last().unwrap().fee_msat).sum();
340                                                         if retry_amt_msat + *pending_amt_msat > *total_msat * (100 + RETRY_OVERFLOW_PERCENTAGE) / 100 {
341                                                                 return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
342                                                                         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()
343                                                                 }))
344                                                         }
345                                                         (*total_msat, *payment_hash, *payment_secret)
346                                                 },
347                                                 PendingOutboundPayment::Legacy { .. } => {
348                                                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
349                                                                 err: "Unable to retry payments that were initially sent on LDK versions prior to 0.0.102".to_string()
350                                                         }))
351                                                 },
352                                                 PendingOutboundPayment::Fulfilled { .. } => {
353                                                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
354                                                                 err: "Payment already completed".to_owned()
355                                                         }));
356                                                 },
357                                                 PendingOutboundPayment::Abandoned { .. } => {
358                                                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
359                                                                 err: "Payment already abandoned (with some HTLCs still pending)".to_owned()
360                                                         }));
361                                                 },
362                                         };
363                                         for (path, session_priv_bytes) in route.paths.iter().zip(onion_session_privs.iter()) {
364                                                 assert!(payment.insert(*session_priv_bytes, path));
365                                         }
366                                         res
367                                 },
368                                 None =>
369                                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
370                                                 err: format!("Payment with ID {} not found", log_bytes!(payment_id.0)),
371                                         })),
372                         }
373                 };
374                 self.send_payment_internal(route, payment_hash, &payment_secret, None, payment_id, Some(total_msat), onion_session_privs, keys_manager, best_block_height, send_payment_along_path)
375         }
376
377         pub(super) fn send_probe<K: Deref, F>(&self, hops: Vec<RouteHop>, probing_cookie_secret: [u8; 32],
378                 keys_manager: &K, best_block_height: u32, send_payment_along_path: F)
379         -> Result<(PaymentHash, PaymentId), PaymentSendFailure>
380         where
381                 K::Target: KeysInterface,
382                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
383                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
384         {
385                 let payment_id = PaymentId(keys_manager.get_secure_random_bytes());
386
387                 let payment_hash = probing_cookie_from_id(&payment_id, probing_cookie_secret);
388
389                 if hops.len() < 2 {
390                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError {
391                                 err: "No need probing a path with less than two hops".to_string()
392                         }))
393                 }
394
395                 let route = Route { paths: vec![hops], payment_params: None };
396                 let onion_session_privs = self.add_new_pending_payment(payment_hash, None, payment_id, &route, keys_manager, best_block_height)?;
397
398                 match self.send_payment_internal(&route, payment_hash, &None, None, payment_id, None, onion_session_privs, keys_manager, best_block_height, send_payment_along_path) {
399                         Ok(()) => Ok((payment_hash, payment_id)),
400                         Err(e) => Err(e)
401                 }
402         }
403
404         pub(super) fn add_new_pending_payment<K: Deref>(&self, payment_hash: PaymentHash,
405                 payment_secret: Option<PaymentSecret>, payment_id: PaymentId, route: &Route, keys_manager: &K,
406                 best_block_height: u32)
407         -> Result<Vec<[u8; 32]>, PaymentSendFailure> where K::Target: KeysInterface {
408                 let mut onion_session_privs = Vec::with_capacity(route.paths.len());
409                 for _ in 0..route.paths.len() {
410                         onion_session_privs.push(keys_manager.get_secure_random_bytes());
411                 }
412
413                 let mut pending_outbounds = self.pending_outbound_payments.lock().unwrap();
414                 match pending_outbounds.entry(payment_id) {
415                         hash_map::Entry::Occupied(_) => Err(PaymentSendFailure::DuplicatePayment),
416                         hash_map::Entry::Vacant(entry) => {
417                                 let payment = entry.insert(PendingOutboundPayment::Retryable {
418                                         session_privs: HashSet::new(),
419                                         pending_amt_msat: 0,
420                                         pending_fee_msat: Some(0),
421                                         payment_hash,
422                                         payment_secret,
423                                         starting_block_height: best_block_height,
424                                         total_msat: route.get_total_amount(),
425                                 });
426
427                                 for (path, session_priv_bytes) in route.paths.iter().zip(onion_session_privs.iter()) {
428                                         assert!(payment.insert(*session_priv_bytes, path));
429                                 }
430
431                                 Ok(onion_session_privs)
432                         },
433                 }
434         }
435
436         fn send_payment_internal<K: Deref, F>
437                 (&self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>,
438                 keysend_preimage: Option<PaymentPreimage>, payment_id: PaymentId, recv_value_msat: Option<u64>,
439                 onion_session_privs: Vec<[u8; 32]>, keys_manager: &K, best_block_height: u32,
440                 send_payment_along_path: F) -> Result<(), PaymentSendFailure>
441         where
442                 K::Target: KeysInterface,
443                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
444                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
445         {
446                 if route.paths.len() < 1 {
447                         return Err(PaymentSendFailure::ParameterError(APIError::InvalidRoute{err: "There must be at least one path to send over"}));
448                 }
449                 if payment_secret.is_none() && route.paths.len() > 1 {
450                         return Err(PaymentSendFailure::ParameterError(APIError::APIMisuseError{err: "Payment secret is required for multi-path payments".to_string()}));
451                 }
452                 let mut total_value = 0;
453                 let our_node_id = keys_manager.get_node_id(Recipient::Node).unwrap(); // TODO no unwrap
454                 let mut path_errs = Vec::with_capacity(route.paths.len());
455                 'path_check: for path in route.paths.iter() {
456                         if path.len() < 1 || path.len() > 20 {
457                                 path_errs.push(Err(APIError::InvalidRoute{err: "Path didn't go anywhere/had bogus size"}));
458                                 continue 'path_check;
459                         }
460                         for (idx, hop) in path.iter().enumerate() {
461                                 if idx != path.len() - 1 && hop.pubkey == our_node_id {
462                                         path_errs.push(Err(APIError::InvalidRoute{err: "Path went through us but wasn't a simple rebalance loop to us"}));
463                                         continue 'path_check;
464                                 }
465                         }
466                         total_value += path.last().unwrap().fee_msat;
467                         path_errs.push(Ok(()));
468                 }
469                 if path_errs.iter().any(|e| e.is_err()) {
470                         return Err(PaymentSendFailure::PathParameterError(path_errs));
471                 }
472                 if let Some(amt_msat) = recv_value_msat {
473                         debug_assert!(amt_msat >= total_value);
474                         total_value = amt_msat;
475                 }
476
477                 let cur_height = best_block_height + 1;
478                 let mut results = Vec::new();
479                 debug_assert_eq!(route.paths.len(), onion_session_privs.len());
480                 for (path, session_priv) in route.paths.iter().zip(onion_session_privs.into_iter()) {
481                         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);
482                         match path_res {
483                                 Ok(_) => {},
484                                 Err(APIError::MonitorUpdateInProgress) => {
485                                         // While a MonitorUpdateInProgress is an Err(_), the payment is still
486                                         // considered "in flight" and we shouldn't remove it from the
487                                         // PendingOutboundPayment set.
488                                 },
489                                 Err(_) => {
490                                         let mut pending_outbounds = self.pending_outbound_payments.lock().unwrap();
491                                         if let Some(payment) = pending_outbounds.get_mut(&payment_id) {
492                                                 let removed = payment.remove(&session_priv, Some(path));
493                                                 debug_assert!(removed, "This can't happen as the payment has an entry for this path added by callers");
494                                         } else {
495                                                 debug_assert!(false, "This can't happen as the payment was added by callers");
496                                                 path_res = Err(APIError::APIMisuseError { err: "Internal error: payment disappeared during processing. Please report this bug!".to_owned() });
497                                         }
498                                 }
499                         }
500                         results.push(path_res);
501                 }
502                 let mut has_ok = false;
503                 let mut has_err = false;
504                 let mut pending_amt_unsent = 0;
505                 let mut max_unsent_cltv_delta = 0;
506                 for (res, path) in results.iter().zip(route.paths.iter()) {
507                         if res.is_ok() { has_ok = true; }
508                         if res.is_err() { has_err = true; }
509                         if let &Err(APIError::MonitorUpdateInProgress) = res {
510                                 // MonitorUpdateInProgress is inherently unsafe to retry, so we call it a
511                                 // PartialFailure.
512                                 has_err = true;
513                                 has_ok = true;
514                         } else if res.is_err() {
515                                 pending_amt_unsent += path.last().unwrap().fee_msat;
516                                 max_unsent_cltv_delta = cmp::max(max_unsent_cltv_delta, path.last().unwrap().cltv_expiry_delta);
517                         }
518                 }
519                 if has_err && has_ok {
520                         Err(PaymentSendFailure::PartialFailure {
521                                 results,
522                                 payment_id,
523                                 failed_paths_retry: if pending_amt_unsent != 0 {
524                                         if let Some(payment_params) = &route.payment_params {
525                                                 Some(RouteParameters {
526                                                         payment_params: payment_params.clone(),
527                                                         final_value_msat: pending_amt_unsent,
528                                                         final_cltv_expiry_delta: max_unsent_cltv_delta,
529                                                 })
530                                         } else { None }
531                                 } else { None },
532                         })
533                 } else if has_err {
534                         // If we failed to send any paths, we should remove the new PaymentId from the
535                         // `pending_outbound_payments` map, as the user isn't expected to `abandon_payment`.
536                         let removed = self.pending_outbound_payments.lock().unwrap().remove(&payment_id).is_some();
537                         debug_assert!(removed, "We should always have a pending payment to remove here");
538                         Err(PaymentSendFailure::AllFailedResendSafe(results.drain(..).map(|r| r.unwrap_err()).collect()))
539                 } else {
540                         Ok(())
541                 }
542         }
543
544         #[cfg(test)]
545         pub(super) fn test_send_payment_internal<K: Deref, F>
546                 (&self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>,
547                  keysend_preimage: Option<PaymentPreimage>, payment_id: PaymentId, recv_value_msat: Option<u64>,
548                  onion_session_privs: Vec<[u8; 32]>, keys_manager: &K, best_block_height: u32,
549                  send_payment_along_path: F) -> Result<(), PaymentSendFailure>
550         where
551                 K::Target: KeysInterface,
552                 F: Fn(&Vec<RouteHop>, &Option<PaymentParameters>, &PaymentHash, &Option<PaymentSecret>, u64,
553                    u32, PaymentId, &Option<PaymentPreimage>, [u8; 32]) -> Result<(), APIError>
554         {
555                 self.send_payment_internal(route, payment_hash, payment_secret, keysend_preimage, payment_id,
556                         recv_value_msat, onion_session_privs, keys_manager, best_block_height,
557                         send_payment_along_path)
558         }
559
560         pub(super) fn claim_htlc<L: Deref>(&self, payment_id: PaymentId,
561                 payment_preimage: PaymentPreimage, session_priv: SecretKey, path: Vec<RouteHop>,
562                 from_onchain: bool, pending_events: &Mutex<Vec<events::Event>>, logger: &L)
563          where L::Target: Logger {
564                 let mut session_priv_bytes = [0; 32];
565                 session_priv_bytes.copy_from_slice(&session_priv[..]);
566                 let mut outbounds = self.pending_outbound_payments.lock().unwrap();
567                 let mut pending_events = pending_events.lock().unwrap();
568                 if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(payment_id) {
569                         if !payment.get().is_fulfilled() {
570                                 let payment_hash = PaymentHash(Sha256::hash(&payment_preimage.0).into_inner());
571                                 let fee_paid_msat = payment.get().get_pending_fee_msat();
572                                 pending_events.push(
573                                         events::Event::PaymentSent {
574                                                 payment_id: Some(payment_id),
575                                                 payment_preimage,
576                                                 payment_hash,
577                                                 fee_paid_msat,
578                                         }
579                                 );
580                                 payment.get_mut().mark_fulfilled();
581                         }
582
583                         if from_onchain {
584                                 // We currently immediately remove HTLCs which were fulfilled on-chain.
585                                 // This could potentially lead to removing a pending payment too early,
586                                 // with a reorg of one block causing us to re-add the fulfilled payment on
587                                 // restart.
588                                 // TODO: We should have a second monitor event that informs us of payments
589                                 // irrevocably fulfilled.
590                                 if payment.get_mut().remove(&session_priv_bytes, Some(&path)) {
591                                         let payment_hash = Some(PaymentHash(Sha256::hash(&payment_preimage.0).into_inner()));
592                                         pending_events.push(
593                                                 events::Event::PaymentPathSuccessful {
594                                                         payment_id,
595                                                         payment_hash,
596                                                         path,
597                                                 }
598                                         );
599                                 }
600                         }
601                 } else {
602                         log_trace!(logger, "Received duplicative fulfill for HTLC with payment_preimage {}", log_bytes!(payment_preimage.0));
603                 }
604         }
605
606         pub(super) fn finalize_claims(&self, sources: Vec<HTLCSource>, pending_events: &Mutex<Vec<events::Event>>) {
607                 let mut outbounds = self.pending_outbound_payments.lock().unwrap();
608                 let mut pending_events = pending_events.lock().unwrap();
609                 for source in sources {
610                         if let HTLCSource::OutboundRoute { session_priv, payment_id, path, .. } = source {
611                                 let mut session_priv_bytes = [0; 32];
612                                 session_priv_bytes.copy_from_slice(&session_priv[..]);
613                                 if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(payment_id) {
614                                         assert!(payment.get().is_fulfilled());
615                                         if payment.get_mut().remove(&session_priv_bytes, None) {
616                                                 pending_events.push(
617                                                         events::Event::PaymentPathSuccessful {
618                                                                 payment_id,
619                                                                 payment_hash: payment.get().payment_hash(),
620                                                                 path,
621                                                         }
622                                                 );
623                                         }
624                                 }
625                         }
626                 }
627         }
628
629         pub(super) fn remove_stale_resolved_payments(&self, pending_events: &Mutex<Vec<events::Event>>) {
630                 // If an outbound payment was completed, and no pending HTLCs remain, we should remove it
631                 // from the map. However, if we did that immediately when the last payment HTLC is claimed,
632                 // this could race the user making a duplicate send_payment call and our idempotency
633                 // guarantees would be violated. Instead, we wait a few timer ticks to do the actual
634                 // removal. This should be more than sufficient to ensure the idempotency of any
635                 // `send_payment` calls that were made at the same time the `PaymentSent` event was being
636                 // processed.
637                 let mut pending_outbound_payments = self.pending_outbound_payments.lock().unwrap();
638                 let pending_events = pending_events.lock().unwrap();
639                 pending_outbound_payments.retain(|payment_id, payment| {
640                         if let PendingOutboundPayment::Fulfilled { session_privs, timer_ticks_without_htlcs, .. } = payment {
641                                 let mut no_remaining_entries = session_privs.is_empty();
642                                 if no_remaining_entries {
643                                         for ev in pending_events.iter() {
644                                                 match ev {
645                                                         events::Event::PaymentSent { payment_id: Some(ev_payment_id), .. } |
646                                                                 events::Event::PaymentPathSuccessful { payment_id: ev_payment_id, .. } |
647                                                                 events::Event::PaymentPathFailed { payment_id: Some(ev_payment_id), .. } => {
648                                                                         if payment_id == ev_payment_id {
649                                                                                 no_remaining_entries = false;
650                                                                                 break;
651                                                                         }
652                                                                 },
653                                                         _ => {},
654                                                 }
655                                         }
656                                 }
657                                 if no_remaining_entries {
658                                         *timer_ticks_without_htlcs += 1;
659                                         *timer_ticks_without_htlcs <= IDEMPOTENCY_TIMEOUT_TICKS
660                                 } else {
661                                         *timer_ticks_without_htlcs = 0;
662                                         true
663                                 }
664                         } else { true }
665                 });
666         }
667
668         pub(super) fn fail_htlc<L: Deref>(&self, source: &HTLCSource, payment_hash: &PaymentHash,
669                 onion_error: &HTLCFailReason, path: &Vec<RouteHop>, session_priv: &SecretKey,
670                 payment_id: &PaymentId, payment_params: &Option<PaymentParameters>,
671                 probing_cookie_secret: [u8; 32], secp_ctx: &Secp256k1<secp256k1::All>,
672                 pending_events: &Mutex<Vec<events::Event>>, logger: &L)
673         where L::Target: Logger {
674                 let mut session_priv_bytes = [0; 32];
675                 session_priv_bytes.copy_from_slice(&session_priv[..]);
676                 let mut outbounds = self.pending_outbound_payments.lock().unwrap();
677                 let mut all_paths_failed = false;
678                 let mut full_failure_ev = None;
679                 if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(*payment_id) {
680                         if !payment.get_mut().remove(&session_priv_bytes, Some(&path)) {
681                                 log_trace!(logger, "Received duplicative fail for HTLC with payment_hash {}", log_bytes!(payment_hash.0));
682                                 return
683                         }
684                         if payment.get().is_fulfilled() {
685                                 log_trace!(logger, "Received failure of HTLC with payment_hash {} after payment completion", log_bytes!(payment_hash.0));
686                                 return
687                         }
688                         if payment.get().remaining_parts() == 0 {
689                                 all_paths_failed = true;
690                                 if payment.get().abandoned() {
691                                         full_failure_ev = Some(events::Event::PaymentFailed {
692                                                 payment_id: *payment_id,
693                                                 payment_hash: payment.get().payment_hash().expect("PendingOutboundPayments::RetriesExceeded always has a payment hash set"),
694                                         });
695                                         payment.remove();
696                                 }
697                         }
698                 } else {
699                         log_trace!(logger, "Received duplicative fail for HTLC with payment_hash {}", log_bytes!(payment_hash.0));
700                         return
701                 }
702                 let mut retry = if let Some(payment_params_data) = payment_params {
703                         let path_last_hop = path.last().expect("Outbound payments must have had a valid path");
704                         Some(RouteParameters {
705                                 payment_params: payment_params_data.clone(),
706                                 final_value_msat: path_last_hop.fee_msat,
707                                 final_cltv_expiry_delta: path_last_hop.cltv_expiry_delta,
708                         })
709                 } else { None };
710                 log_trace!(logger, "Failing outbound payment HTLC with payment_hash {}", log_bytes!(payment_hash.0));
711
712                 let path_failure = {
713         #[cfg(test)]
714                         let (network_update, short_channel_id, payment_retryable, onion_error_code, onion_error_data) = onion_error.decode_onion_failure(secp_ctx, logger, &source);
715         #[cfg(not(test))]
716                         let (network_update, short_channel_id, payment_retryable, _, _) = onion_error.decode_onion_failure(secp_ctx, logger, &source);
717
718                         if payment_is_probe(payment_hash, &payment_id, probing_cookie_secret) {
719                                 if !payment_retryable {
720                                         events::Event::ProbeSuccessful {
721                                                 payment_id: *payment_id,
722                                                 payment_hash: payment_hash.clone(),
723                                                 path: path.clone(),
724                                         }
725                                 } else {
726                                         events::Event::ProbeFailed {
727                                                 payment_id: *payment_id,
728                                                 payment_hash: payment_hash.clone(),
729                                                 path: path.clone(),
730                                                 short_channel_id,
731                                         }
732                                 }
733                         } else {
734                                 // TODO: If we decided to blame ourselves (or one of our channels) in
735                                 // process_onion_failure we should close that channel as it implies our
736                                 // next-hop is needlessly blaming us!
737                                 if let Some(scid) = short_channel_id {
738                                         retry.as_mut().map(|r| r.payment_params.previously_failed_channels.push(scid));
739                                 }
740                                 events::Event::PaymentPathFailed {
741                                         payment_id: Some(*payment_id),
742                                         payment_hash: payment_hash.clone(),
743                                         payment_failed_permanently: !payment_retryable,
744                                         network_update,
745                                         all_paths_failed,
746                                         path: path.clone(),
747                                         short_channel_id,
748                                         retry,
749                                         #[cfg(test)]
750                                         error_code: onion_error_code,
751                                         #[cfg(test)]
752                                         error_data: onion_error_data
753                                 }
754                         }
755                 };
756                 let mut pending_events = pending_events.lock().unwrap();
757                 pending_events.push(path_failure);
758                 if let Some(ev) = full_failure_ev { pending_events.push(ev); }
759         }
760
761         pub(super) fn abandon_payment(&self, payment_id: PaymentId) -> Option<events::Event> {
762                 let mut failed_ev = None;
763                 let mut outbounds = self.pending_outbound_payments.lock().unwrap();
764                 if let hash_map::Entry::Occupied(mut payment) = outbounds.entry(payment_id) {
765                         if let Ok(()) = payment.get_mut().mark_abandoned() {
766                                 if payment.get().remaining_parts() == 0 {
767                                         failed_ev = Some(events::Event::PaymentFailed {
768                                                 payment_id,
769                                                 payment_hash: payment.get().payment_hash().expect("PendingOutboundPayments::RetriesExceeded always has a payment hash set"),
770                                         });
771                                         payment.remove();
772                                 }
773                         }
774                 }
775                 failed_ev
776         }
777
778         #[cfg(test)]
779         pub fn has_pending_payments(&self) -> bool {
780                 !self.pending_outbound_payments.lock().unwrap().is_empty()
781         }
782
783         #[cfg(test)]
784         pub fn clear_pending_payments(&self) {
785                 self.pending_outbound_payments.lock().unwrap().clear()
786         }
787 }
788
789 /// Returns whether a payment with the given [`PaymentHash`] and [`PaymentId`] is, in fact, a
790 /// payment probe.
791 pub(super) fn payment_is_probe(payment_hash: &PaymentHash, payment_id: &PaymentId,
792         probing_cookie_secret: [u8; 32]) -> bool
793 {
794         let target_payment_hash = probing_cookie_from_id(payment_id, probing_cookie_secret);
795         target_payment_hash == *payment_hash
796 }
797
798 /// Returns the 'probing cookie' for the given [`PaymentId`].
799 fn probing_cookie_from_id(payment_id: &PaymentId, probing_cookie_secret: [u8; 32]) -> PaymentHash {
800         let mut preimage = [0u8; 64];
801         preimage[..32].copy_from_slice(&probing_cookie_secret);
802         preimage[32..].copy_from_slice(&payment_id.0);
803         PaymentHash(Sha256::hash(&preimage).into_inner())
804 }
805
806 impl_writeable_tlv_based_enum_upgradable!(PendingOutboundPayment,
807         (0, Legacy) => {
808                 (0, session_privs, required),
809         },
810         (1, Fulfilled) => {
811                 (0, session_privs, required),
812                 (1, payment_hash, option),
813                 (3, timer_ticks_without_htlcs, (default_value, 0)),
814         },
815         (2, Retryable) => {
816                 (0, session_privs, required),
817                 (1, pending_fee_msat, option),
818                 (2, payment_hash, required),
819                 (4, payment_secret, option),
820                 (6, total_msat, required),
821                 (8, pending_amt_msat, required),
822                 (10, starting_block_height, required),
823         },
824         (3, Abandoned) => {
825                 (0, session_privs, required),
826                 (2, payment_hash, required),
827         },
828 );