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[rust-lightning] / lightning / src / chain / chainmonitor.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 //! Logic to connect off-chain channel management with on-chain transaction monitoring.
11 //!
12 //! [`ChainMonitor`] is an implementation of [`chain::Watch`] used both to process blocks and to
13 //! update [`ChannelMonitor`]s accordingly. If any on-chain events need further processing, it will
14 //! make those available as [`MonitorEvent`]s to be consumed.
15 //!
16 //! [`ChainMonitor`] is parameterized by an optional chain source, which must implement the
17 //! [`chain::Filter`] trait. This provides a mechanism to signal new relevant outputs back to light
18 //! clients, such that transactions spending those outputs are included in block data.
19 //!
20 //! [`ChainMonitor`] may be used directly to monitor channels locally or as a part of a distributed
21 //! setup to monitor channels remotely. In the latter case, a custom [`chain::Watch`] implementation
22 //! would be responsible for routing each update to a remote server and for retrieving monitor
23 //! events. The remote server would make use of [`ChainMonitor`] for block processing and for
24 //! servicing [`ChannelMonitor`] updates from the client.
25
26 use bitcoin::blockdata::block::Header;
27 use bitcoin::hash_types::{Txid, BlockHash};
28
29 use crate::chain;
30 use crate::chain::{ChannelMonitorUpdateStatus, Filter, WatchedOutput};
31 use crate::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
32 use crate::chain::channelmonitor::{ChannelMonitor, ChannelMonitorUpdate, Balance, MonitorEvent, TransactionOutputs, WithChannelMonitor, LATENCY_GRACE_PERIOD_BLOCKS};
33 use crate::chain::transaction::{OutPoint, TransactionData};
34 use crate::ln::ChannelId;
35 use crate::sign::ecdsa::WriteableEcdsaChannelSigner;
36 use crate::events;
37 use crate::events::{Event, EventHandler};
38 use crate::util::atomic_counter::AtomicCounter;
39 use crate::util::logger::{Logger, WithContext};
40 use crate::util::errors::APIError;
41 use crate::util::wakers::{Future, Notifier};
42 use crate::ln::channelmanager::ChannelDetails;
43
44 use crate::prelude::*;
45 use crate::sync::{RwLock, RwLockReadGuard, Mutex, MutexGuard};
46 use core::ops::Deref;
47 use core::sync::atomic::{AtomicUsize, Ordering};
48 use bitcoin::secp256k1::PublicKey;
49
50 mod update_origin {
51         #[derive(Debug, Clone, Copy, Hash, PartialEq, Eq)]
52         /// A specific update's ID stored in a `MonitorUpdateId`, separated out to make the contents
53         /// entirely opaque.
54         pub(crate) enum UpdateOrigin {
55                 /// An update that was generated by the `ChannelManager` (via our [`crate::chain::Watch`]
56                 /// implementation). This corresponds to an actual [ChannelMonitorUpdate::update_id] field
57                 /// and [ChannelMonitor::get_latest_update_id].
58                 ///
59                 /// [ChannelMonitor::get_latest_update_id]: crate::chain::channelmonitor::ChannelMonitor::get_latest_update_id
60                 /// [ChannelMonitorUpdate::update_id]: crate::chain::channelmonitor::ChannelMonitorUpdate::update_id
61                 OffChain(u64),
62                 /// An update that was generated during blockchain processing. The ID here is specific to the
63                 /// generating [ChannelMonitor] and does *not* correspond to any on-disk IDs.
64                 ///
65                 /// [ChannelMonitor]: crate::chain::channelmonitor::ChannelMonitor
66                 ChainSync(u64),
67         }
68 }
69
70 #[cfg(any(feature = "_test_utils", test))]
71 pub(crate) use update_origin::UpdateOrigin;
72 #[cfg(not(any(feature = "_test_utils", test)))]
73 use update_origin::UpdateOrigin;
74
75 /// An opaque identifier describing a specific [`Persist`] method call.
76 #[derive(Debug, Clone, Copy, Hash, PartialEq, Eq)]
77 pub struct MonitorUpdateId {
78         pub(crate) contents: UpdateOrigin,
79 }
80
81 impl MonitorUpdateId {
82         pub(crate) fn from_monitor_update(update: &ChannelMonitorUpdate) -> Self {
83                 Self { contents: UpdateOrigin::OffChain(update.update_id) }
84         }
85         pub(crate) fn from_new_monitor<ChannelSigner: WriteableEcdsaChannelSigner>(monitor: &ChannelMonitor<ChannelSigner>) -> Self {
86                 Self { contents: UpdateOrigin::OffChain(monitor.get_latest_update_id()) }
87         }
88 }
89
90 /// `Persist` defines behavior for persisting channel monitors: this could mean
91 /// writing once to disk, and/or uploading to one or more backup services.
92 ///
93 /// Persistence can happen in one of two ways - synchronously completing before the trait method
94 /// calls return or asynchronously in the background.
95 ///
96 /// # For those implementing synchronous persistence
97 ///
98 ///  * If persistence completes fully (including any relevant `fsync()` calls), the implementation
99 ///    should return [`ChannelMonitorUpdateStatus::Completed`], indicating normal channel operation
100 ///    should continue.
101 ///
102 ///  * If persistence fails for some reason, implementations should consider returning
103 ///    [`ChannelMonitorUpdateStatus::InProgress`] and retry all pending persistence operations in
104 ///    the background with [`ChainMonitor::list_pending_monitor_updates`] and
105 ///    [`ChainMonitor::get_monitor`].
106 ///
107 ///    Once a full [`ChannelMonitor`] has been persisted, all pending updates for that channel can
108 ///    be marked as complete via [`ChainMonitor::channel_monitor_updated`].
109 ///
110 ///    If at some point no further progress can be made towards persisting the pending updates, the
111 ///    node should simply shut down.
112 ///
113 ///  * If the persistence has failed and cannot be retried further (e.g. because of an outage),
114 ///    [`ChannelMonitorUpdateStatus::UnrecoverableError`] can be used, though this will result in
115 ///    an immediate panic and future operations in LDK generally failing.
116 ///
117 /// # For those implementing asynchronous persistence
118 ///
119 ///  All calls should generally spawn a background task and immediately return
120 ///  [`ChannelMonitorUpdateStatus::InProgress`]. Once the update completes,
121 ///  [`ChainMonitor::channel_monitor_updated`] should be called with the corresponding
122 ///  [`MonitorUpdateId`].
123 ///
124 ///  Note that unlike the direct [`chain::Watch`] interface,
125 ///  [`ChainMonitor::channel_monitor_updated`] must be called once for *each* update which occurs.
126 ///
127 ///  If at some point no further progress can be made towards persisting a pending update, the node
128 ///  should simply shut down. Until then, the background task should either loop indefinitely, or
129 ///  persistence should be regularly retried with [`ChainMonitor::list_pending_monitor_updates`]
130 ///  and [`ChainMonitor::get_monitor`] (note that if a full monitor is persisted all pending
131 ///  monitor updates may be marked completed).
132 ///
133 /// # Using remote watchtowers
134 ///
135 /// Watchtowers may be updated as a part of an implementation of this trait, utilizing the async
136 /// update process described above while the watchtower is being updated. The following methods are
137 /// provided for bulding transactions for a watchtower:
138 /// [`ChannelMonitor::initial_counterparty_commitment_tx`],
139 /// [`ChannelMonitor::counterparty_commitment_txs_from_update`],
140 /// [`ChannelMonitor::sign_to_local_justice_tx`], [`TrustedCommitmentTransaction::revokeable_output_index`],
141 /// [`TrustedCommitmentTransaction::build_to_local_justice_tx`].
142 ///
143 /// [`TrustedCommitmentTransaction::revokeable_output_index`]: crate::ln::chan_utils::TrustedCommitmentTransaction::revokeable_output_index
144 /// [`TrustedCommitmentTransaction::build_to_local_justice_tx`]: crate::ln::chan_utils::TrustedCommitmentTransaction::build_to_local_justice_tx
145 pub trait Persist<ChannelSigner: WriteableEcdsaChannelSigner> {
146         /// Persist a new channel's data in response to a [`chain::Watch::watch_channel`] call. This is
147         /// called by [`ChannelManager`] for new channels, or may be called directly, e.g. on startup.
148         ///
149         /// The data can be stored any way you want, but the identifier provided by LDK is the
150         /// channel's outpoint (and it is up to you to maintain a correct mapping between the outpoint
151         /// and the stored channel data). Note that you **must** persist every new monitor to disk.
152         ///
153         /// The `update_id` is used to identify this call to [`ChainMonitor::channel_monitor_updated`],
154         /// if you return [`ChannelMonitorUpdateStatus::InProgress`].
155         ///
156         /// See [`Writeable::write`] on [`ChannelMonitor`] for writing out a `ChannelMonitor`
157         /// and [`ChannelMonitorUpdateStatus`] for requirements when returning errors.
158         ///
159         /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
160         /// [`Writeable::write`]: crate::util::ser::Writeable::write
161         fn persist_new_channel(&self, channel_funding_outpoint: OutPoint, data: &ChannelMonitor<ChannelSigner>, update_id: MonitorUpdateId) -> ChannelMonitorUpdateStatus;
162
163         /// Update one channel's data. The provided [`ChannelMonitor`] has already applied the given
164         /// update.
165         ///
166         /// Note that on every update, you **must** persist either the [`ChannelMonitorUpdate`] or the
167         /// updated monitor itself to disk/backups. See the [`Persist`] trait documentation for more
168         /// details.
169         ///
170         /// During blockchain synchronization operations, and in some rare cases, this may be called with
171         /// no [`ChannelMonitorUpdate`], in which case the full [`ChannelMonitor`] needs to be persisted.
172         /// Note that after the full [`ChannelMonitor`] is persisted any previous
173         /// [`ChannelMonitorUpdate`]s which were persisted should be discarded - they can no longer be
174         /// applied to the persisted [`ChannelMonitor`] as they were already applied.
175         ///
176         /// If an implementer chooses to persist the updates only, they need to make
177         /// sure that all the updates are applied to the `ChannelMonitors` *before*
178         /// the set of channel monitors is given to the `ChannelManager`
179         /// deserialization routine. See [`ChannelMonitor::update_monitor`] for
180         /// applying a monitor update to a monitor. If full `ChannelMonitors` are
181         /// persisted, then there is no need to persist individual updates.
182         ///
183         /// Note that there could be a performance tradeoff between persisting complete
184         /// channel monitors on every update vs. persisting only updates and applying
185         /// them in batches. The size of each monitor grows `O(number of state updates)`
186         /// whereas updates are small and `O(1)`.
187         ///
188         /// The `update_id` is used to identify this call to [`ChainMonitor::channel_monitor_updated`],
189         /// if you return [`ChannelMonitorUpdateStatus::InProgress`].
190         ///
191         /// See [`Writeable::write`] on [`ChannelMonitor`] for writing out a `ChannelMonitor`,
192         /// [`Writeable::write`] on [`ChannelMonitorUpdate`] for writing out an update, and
193         /// [`ChannelMonitorUpdateStatus`] for requirements when returning errors.
194         ///
195         /// [`Writeable::write`]: crate::util::ser::Writeable::write
196         fn update_persisted_channel(&self, channel_funding_outpoint: OutPoint, update: Option<&ChannelMonitorUpdate>, data: &ChannelMonitor<ChannelSigner>, update_id: MonitorUpdateId) -> ChannelMonitorUpdateStatus;
197 }
198
199 struct MonitorHolder<ChannelSigner: WriteableEcdsaChannelSigner> {
200         monitor: ChannelMonitor<ChannelSigner>,
201         /// The full set of pending monitor updates for this Channel.
202         ///
203         /// Note that this lock must be held during updates to prevent a race where we call
204         /// update_persisted_channel, the user returns a
205         /// [`ChannelMonitorUpdateStatus::InProgress`], and then calls channel_monitor_updated
206         /// immediately, racing our insertion of the pending update into the contained Vec.
207         ///
208         /// Beyond the synchronization of updates themselves, we cannot handle user events until after
209         /// any chain updates have been stored on disk. Thus, we scan this list when returning updates
210         /// to the ChannelManager, refusing to return any updates for a ChannelMonitor which is still
211         /// being persisted fully to disk after a chain update.
212         ///
213         /// This avoids the possibility of handling, e.g. an on-chain claim, generating a claim monitor
214         /// event, resulting in the relevant ChannelManager generating a PaymentSent event and dropping
215         /// the pending payment entry, and then reloading before the monitor is persisted, resulting in
216         /// the ChannelManager re-adding the same payment entry, before the same block is replayed,
217         /// resulting in a duplicate PaymentSent event.
218         pending_monitor_updates: Mutex<Vec<MonitorUpdateId>>,
219         /// The last block height at which no [`UpdateOrigin::ChainSync`] monitor updates were present
220         /// in `pending_monitor_updates`.
221         /// If it's been more than [`LATENCY_GRACE_PERIOD_BLOCKS`] since we started waiting on a chain
222         /// sync event, we let monitor events return to `ChannelManager` because we cannot hold them up
223         /// forever or we'll end up with HTLC preimages waiting to feed back into an upstream channel
224         /// forever, risking funds loss.
225         last_chain_persist_height: AtomicUsize,
226 }
227
228 impl<ChannelSigner: WriteableEcdsaChannelSigner> MonitorHolder<ChannelSigner> {
229         fn has_pending_offchain_updates(&self, pending_monitor_updates_lock: &MutexGuard<Vec<MonitorUpdateId>>) -> bool {
230                 pending_monitor_updates_lock.iter().any(|update_id|
231                         if let UpdateOrigin::OffChain(_) = update_id.contents { true } else { false })
232         }
233         fn has_pending_chainsync_updates(&self, pending_monitor_updates_lock: &MutexGuard<Vec<MonitorUpdateId>>) -> bool {
234                 pending_monitor_updates_lock.iter().any(|update_id|
235                         if let UpdateOrigin::ChainSync(_) = update_id.contents { true } else { false })
236         }
237 }
238
239 /// A read-only reference to a current ChannelMonitor.
240 ///
241 /// Note that this holds a mutex in [`ChainMonitor`] and may block other events until it is
242 /// released.
243 pub struct LockedChannelMonitor<'a, ChannelSigner: WriteableEcdsaChannelSigner> {
244         lock: RwLockReadGuard<'a, HashMap<OutPoint, MonitorHolder<ChannelSigner>>>,
245         funding_txo: OutPoint,
246 }
247
248 impl<ChannelSigner: WriteableEcdsaChannelSigner> Deref for LockedChannelMonitor<'_, ChannelSigner> {
249         type Target = ChannelMonitor<ChannelSigner>;
250         fn deref(&self) -> &ChannelMonitor<ChannelSigner> {
251                 &self.lock.get(&self.funding_txo).expect("Checked at construction").monitor
252         }
253 }
254
255 /// An implementation of [`chain::Watch`] for monitoring channels.
256 ///
257 /// Connected and disconnected blocks must be provided to `ChainMonitor` as documented by
258 /// [`chain::Watch`]. May be used in conjunction with [`ChannelManager`] to monitor channels locally
259 /// or used independently to monitor channels remotely. See the [module-level documentation] for
260 /// details.
261 ///
262 /// Note that `ChainMonitor` should regularly trigger rebroadcasts/fee bumps of pending claims from
263 /// a force-closed channel. This is crucial in preventing certain classes of pinning attacks,
264 /// detecting substantial mempool feerate changes between blocks, and ensuring reliability if
265 /// broadcasting fails. We recommend invoking this every 30 seconds, or lower if running in an
266 /// environment with spotty connections, like on mobile.
267 ///
268 /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
269 /// [module-level documentation]: crate::chain::chainmonitor
270 /// [`rebroadcast_pending_claims`]: Self::rebroadcast_pending_claims
271 pub struct ChainMonitor<ChannelSigner: WriteableEcdsaChannelSigner, C: Deref, T: Deref, F: Deref, L: Deref, P: Deref>
272         where C::Target: chain::Filter,
273         T::Target: BroadcasterInterface,
274         F::Target: FeeEstimator,
275         L::Target: Logger,
276         P::Target: Persist<ChannelSigner>,
277 {
278         monitors: RwLock<HashMap<OutPoint, MonitorHolder<ChannelSigner>>>,
279         /// When we generate a [`MonitorUpdateId`] for a chain-event monitor persistence, we need a
280         /// unique ID, which we calculate by simply getting the next value from this counter. Note that
281         /// the ID is never persisted so it's ok that they reset on restart.
282         sync_persistence_id: AtomicCounter,
283         chain_source: Option<C>,
284         broadcaster: T,
285         logger: L,
286         fee_estimator: F,
287         persister: P,
288         /// "User-provided" (ie persistence-completion/-failed) [`MonitorEvent`]s. These came directly
289         /// from the user and not from a [`ChannelMonitor`].
290         pending_monitor_events: Mutex<Vec<(OutPoint, ChannelId, Vec<MonitorEvent>, Option<PublicKey>)>>,
291         /// The best block height seen, used as a proxy for the passage of time.
292         highest_chain_height: AtomicUsize,
293
294         event_notifier: Notifier,
295 }
296
297 impl<ChannelSigner: WriteableEcdsaChannelSigner, C: Deref, T: Deref, F: Deref, L: Deref, P: Deref> ChainMonitor<ChannelSigner, C, T, F, L, P>
298 where C::Target: chain::Filter,
299             T::Target: BroadcasterInterface,
300             F::Target: FeeEstimator,
301             L::Target: Logger,
302             P::Target: Persist<ChannelSigner>,
303 {
304         /// Dispatches to per-channel monitors, which are responsible for updating their on-chain view
305         /// of a channel and reacting accordingly based on transactions in the given chain data. See
306         /// [`ChannelMonitor::block_connected`] for details. Any HTLCs that were resolved on chain will
307         /// be returned by [`chain::Watch::release_pending_monitor_events`].
308         ///
309         /// Calls back to [`chain::Filter`] if any monitor indicated new outputs to watch. Subsequent
310         /// calls must not exclude any transactions matching the new outputs nor any in-block
311         /// descendants of such transactions. It is not necessary to re-fetch the block to obtain
312         /// updated `txdata`.
313         ///
314         /// Calls which represent a new blockchain tip height should set `best_height`.
315         fn process_chain_data<FN>(&self, header: &Header, best_height: Option<u32>, txdata: &TransactionData, process: FN)
316         where
317                 FN: Fn(&ChannelMonitor<ChannelSigner>, &TransactionData) -> Vec<TransactionOutputs>
318         {
319                 let err_str = "ChannelMonitor[Update] persistence failed unrecoverably. This indicates we cannot continue normal operation and must shut down.";
320                 let funding_outpoints = hash_set_from_iter(self.monitors.read().unwrap().keys().cloned());
321                 for funding_outpoint in funding_outpoints.iter() {
322                         let monitor_lock = self.monitors.read().unwrap();
323                         if let Some(monitor_state) = monitor_lock.get(funding_outpoint) {
324                                 if self.update_monitor_with_chain_data(header, best_height, txdata, &process, funding_outpoint, &monitor_state).is_err() {
325                                         // Take the monitors lock for writing so that we poison it and any future
326                                         // operations going forward fail immediately.
327                                         core::mem::drop(monitor_lock);
328                                         let _poison = self.monitors.write().unwrap();
329                                         log_error!(self.logger, "{}", err_str);
330                                         panic!("{}", err_str);
331                                 }
332                         }
333                 }
334
335                 // do some followup cleanup if any funding outpoints were added in between iterations
336                 let monitor_states = self.monitors.write().unwrap();
337                 for (funding_outpoint, monitor_state) in monitor_states.iter() {
338                         if !funding_outpoints.contains(funding_outpoint) {
339                                 if self.update_monitor_with_chain_data(header, best_height, txdata, &process, funding_outpoint, &monitor_state).is_err() {
340                                         log_error!(self.logger, "{}", err_str);
341                                         panic!("{}", err_str);
342                                 }
343                         }
344                 }
345
346                 if let Some(height) = best_height {
347                         // If the best block height is being updated, update highest_chain_height under the
348                         // monitors write lock.
349                         let old_height = self.highest_chain_height.load(Ordering::Acquire);
350                         let new_height = height as usize;
351                         if new_height > old_height {
352                                 self.highest_chain_height.store(new_height, Ordering::Release);
353                         }
354                 }
355         }
356
357         fn update_monitor_with_chain_data<FN>(
358                 &self, header: &Header, best_height: Option<u32>, txdata: &TransactionData,
359                 process: FN, funding_outpoint: &OutPoint, monitor_state: &MonitorHolder<ChannelSigner>
360         ) -> Result<(), ()> where FN: Fn(&ChannelMonitor<ChannelSigner>, &TransactionData) -> Vec<TransactionOutputs> {
361                 let monitor = &monitor_state.monitor;
362                 let logger = WithChannelMonitor::from(&self.logger, &monitor);
363                 let mut txn_outputs;
364                 {
365                         txn_outputs = process(monitor, txdata);
366                         let update_id = MonitorUpdateId {
367                                 contents: UpdateOrigin::ChainSync(self.sync_persistence_id.get_increment()),
368                         };
369                         let mut pending_monitor_updates = monitor_state.pending_monitor_updates.lock().unwrap();
370                         if let Some(height) = best_height {
371                                 if !monitor_state.has_pending_chainsync_updates(&pending_monitor_updates) {
372                                         // If there are not ChainSync persists awaiting completion, go ahead and
373                                         // set last_chain_persist_height here - we wouldn't want the first
374                                         // InProgress to always immediately be considered "overly delayed".
375                                         monitor_state.last_chain_persist_height.store(height as usize, Ordering::Release);
376                                 }
377                         }
378
379                         log_trace!(logger, "Syncing Channel Monitor for channel {}", log_funding_info!(monitor));
380                         match self.persister.update_persisted_channel(*funding_outpoint, None, monitor, update_id) {
381                                 ChannelMonitorUpdateStatus::Completed =>
382                                         log_trace!(logger, "Finished syncing Channel Monitor for channel {}", log_funding_info!(monitor)),
383                                 ChannelMonitorUpdateStatus::InProgress => {
384                                         log_debug!(logger, "Channel Monitor sync for channel {} in progress, holding events until completion!", log_funding_info!(monitor));
385                                         pending_monitor_updates.push(update_id);
386                                 },
387                                 ChannelMonitorUpdateStatus::UnrecoverableError => {
388                                         return Err(());
389                                 },
390                         }
391                 }
392
393                 // Register any new outputs with the chain source for filtering, storing any dependent
394                 // transactions from within the block that previously had not been included in txdata.
395                 if let Some(ref chain_source) = self.chain_source {
396                         let block_hash = header.block_hash();
397                         for (txid, mut outputs) in txn_outputs.drain(..) {
398                                 for (idx, output) in outputs.drain(..) {
399                                         // Register any new outputs with the chain source for filtering
400                                         let output = WatchedOutput {
401                                                 block_hash: Some(block_hash),
402                                                 outpoint: OutPoint { txid, index: idx as u16 },
403                                                 script_pubkey: output.script_pubkey,
404                                         };
405                                         log_trace!(logger, "Adding monitoring for spends of outpoint {} to the filter", output.outpoint);
406                                         chain_source.register_output(output);
407                                 }
408                         }
409                 }
410                 Ok(())
411         }
412
413         /// Creates a new `ChainMonitor` used to watch on-chain activity pertaining to channels.
414         ///
415         /// When an optional chain source implementing [`chain::Filter`] is provided, the chain monitor
416         /// will call back to it indicating transactions and outputs of interest. This allows clients to
417         /// pre-filter blocks or only fetch blocks matching a compact filter. Otherwise, clients may
418         /// always need to fetch full blocks absent another means for determining which blocks contain
419         /// transactions relevant to the watched channels.
420         pub fn new(chain_source: Option<C>, broadcaster: T, logger: L, feeest: F, persister: P) -> Self {
421                 Self {
422                         monitors: RwLock::new(new_hash_map()),
423                         sync_persistence_id: AtomicCounter::new(),
424                         chain_source,
425                         broadcaster,
426                         logger,
427                         fee_estimator: feeest,
428                         persister,
429                         pending_monitor_events: Mutex::new(Vec::new()),
430                         highest_chain_height: AtomicUsize::new(0),
431                         event_notifier: Notifier::new(),
432                 }
433         }
434
435         /// Gets the balances in the contained [`ChannelMonitor`]s which are claimable on-chain or
436         /// claims which are awaiting confirmation.
437         ///
438         /// Includes the balances from each [`ChannelMonitor`] *except* those included in
439         /// `ignored_channels`, allowing you to filter out balances from channels which are still open
440         /// (and whose balance should likely be pulled from the [`ChannelDetails`]).
441         ///
442         /// See [`ChannelMonitor::get_claimable_balances`] for more details on the exact criteria for
443         /// inclusion in the return value.
444         pub fn get_claimable_balances(&self, ignored_channels: &[&ChannelDetails]) -> Vec<Balance> {
445                 let mut ret = Vec::new();
446                 let monitor_states = self.monitors.read().unwrap();
447                 for (_, monitor_state) in monitor_states.iter().filter(|(funding_outpoint, _)| {
448                         for chan in ignored_channels {
449                                 if chan.funding_txo.as_ref() == Some(funding_outpoint) {
450                                         return false;
451                                 }
452                         }
453                         true
454                 }) {
455                         ret.append(&mut monitor_state.monitor.get_claimable_balances());
456                 }
457                 ret
458         }
459
460         /// Gets the [`LockedChannelMonitor`] for a given funding outpoint, returning an `Err` if no
461         /// such [`ChannelMonitor`] is currently being monitored for.
462         ///
463         /// Note that the result holds a mutex over our monitor set, and should not be held
464         /// indefinitely.
465         pub fn get_monitor(&self, funding_txo: OutPoint) -> Result<LockedChannelMonitor<'_, ChannelSigner>, ()> {
466                 let lock = self.monitors.read().unwrap();
467                 if lock.get(&funding_txo).is_some() {
468                         Ok(LockedChannelMonitor { lock, funding_txo })
469                 } else {
470                         Err(())
471                 }
472         }
473
474         /// Lists the funding outpoint and channel ID of each [`ChannelMonitor`] being monitored.
475         ///
476         /// Note that [`ChannelMonitor`]s are not removed when a channel is closed as they are always
477         /// monitoring for on-chain state resolutions.
478         pub fn list_monitors(&self) -> Vec<(OutPoint, ChannelId)> {
479                 self.monitors.read().unwrap().iter().map(|(outpoint, monitor_holder)| {
480                         let channel_id = monitor_holder.monitor.channel_id();
481                         (*outpoint, channel_id)
482                 }).collect()
483         }
484
485         #[cfg(not(c_bindings))]
486         /// Lists the pending updates for each [`ChannelMonitor`] (by `OutPoint` being monitored).
487         pub fn list_pending_monitor_updates(&self) -> HashMap<OutPoint, Vec<MonitorUpdateId>> {
488                 hash_map_from_iter(self.monitors.read().unwrap().iter().map(|(outpoint, holder)| {
489                         (*outpoint, holder.pending_monitor_updates.lock().unwrap().clone())
490                 }))
491         }
492
493         #[cfg(c_bindings)]
494         /// Lists the pending updates for each [`ChannelMonitor`] (by `OutPoint` being monitored).
495         pub fn list_pending_monitor_updates(&self) -> Vec<(OutPoint, Vec<MonitorUpdateId>)> {
496                 self.monitors.read().unwrap().iter().map(|(outpoint, holder)| {
497                         (*outpoint, holder.pending_monitor_updates.lock().unwrap().clone())
498                 }).collect()
499         }
500
501
502         #[cfg(test)]
503         pub fn remove_monitor(&self, funding_txo: &OutPoint) -> ChannelMonitor<ChannelSigner> {
504                 self.monitors.write().unwrap().remove(funding_txo).unwrap().monitor
505         }
506
507         /// Indicates the persistence of a [`ChannelMonitor`] has completed after
508         /// [`ChannelMonitorUpdateStatus::InProgress`] was returned from an update operation.
509         ///
510         /// Thus, the anticipated use is, at a high level:
511         ///  1) This [`ChainMonitor`] calls [`Persist::update_persisted_channel`] which stores the
512         ///     update to disk and begins updating any remote (e.g. watchtower/backup) copies,
513         ///     returning [`ChannelMonitorUpdateStatus::InProgress`],
514         ///  2) once all remote copies are updated, you call this function with the
515         ///     `completed_update_id` that completed, and once all pending updates have completed the
516         ///     channel will be re-enabled.
517         //      Note that we re-enable only after `UpdateOrigin::OffChain` updates complete, we don't
518         //      care about `UpdateOrigin::ChainSync` updates for the channel state being updated. We
519         //      only care about `UpdateOrigin::ChainSync` for returning `MonitorEvent`s.
520         ///
521         /// Returns an [`APIError::APIMisuseError`] if `funding_txo` does not match any currently
522         /// registered [`ChannelMonitor`]s.
523         pub fn channel_monitor_updated(&self, funding_txo: OutPoint, completed_update_id: MonitorUpdateId) -> Result<(), APIError> {
524                 let monitors = self.monitors.read().unwrap();
525                 let monitor_data = if let Some(mon) = monitors.get(&funding_txo) { mon } else {
526                         return Err(APIError::APIMisuseError { err: format!("No ChannelMonitor matching funding outpoint {:?} found", funding_txo) });
527                 };
528                 let mut pending_monitor_updates = monitor_data.pending_monitor_updates.lock().unwrap();
529                 pending_monitor_updates.retain(|update_id| *update_id != completed_update_id);
530
531                 match completed_update_id {
532                         MonitorUpdateId { contents: UpdateOrigin::OffChain(_) } => {
533                                 // Note that we only check for `UpdateOrigin::OffChain` failures here - if
534                                 // we're being told that a `UpdateOrigin::OffChain` monitor update completed,
535                                 // we only care about ensuring we don't tell the `ChannelManager` to restore
536                                 // the channel to normal operation until all `UpdateOrigin::OffChain` updates
537                                 // complete.
538                                 // If there's some `UpdateOrigin::ChainSync` update still pending that's okay
539                                 // - we can still update our channel state, just as long as we don't return
540                                 // `MonitorEvent`s from the monitor back to the `ChannelManager` until they
541                                 // complete.
542                                 let monitor_is_pending_updates = monitor_data.has_pending_offchain_updates(&pending_monitor_updates);
543                                 if monitor_is_pending_updates {
544                                         // If there are still monitor updates pending, we cannot yet construct a
545                                         // Completed event.
546                                         return Ok(());
547                                 }
548                                 let channel_id = monitor_data.monitor.channel_id();
549                                 self.pending_monitor_events.lock().unwrap().push((funding_txo, channel_id, vec![MonitorEvent::Completed {
550                                         funding_txo, channel_id,
551                                         monitor_update_id: monitor_data.monitor.get_latest_update_id(),
552                                 }], monitor_data.monitor.get_counterparty_node_id()));
553                         },
554                         MonitorUpdateId { contents: UpdateOrigin::ChainSync(_) } => {
555                                 if !monitor_data.has_pending_chainsync_updates(&pending_monitor_updates) {
556                                         monitor_data.last_chain_persist_height.store(self.highest_chain_height.load(Ordering::Acquire), Ordering::Release);
557                                         // The next time release_pending_monitor_events is called, any events for this
558                                         // ChannelMonitor will be returned.
559                                 }
560                         },
561                 }
562                 self.event_notifier.notify();
563                 Ok(())
564         }
565
566         /// This wrapper avoids having to update some of our tests for now as they assume the direct
567         /// chain::Watch API wherein we mark a monitor fully-updated by just calling
568         /// channel_monitor_updated once with the highest ID.
569         #[cfg(any(test, fuzzing))]
570         pub fn force_channel_monitor_updated(&self, funding_txo: OutPoint, monitor_update_id: u64) {
571                 let monitors = self.monitors.read().unwrap();
572                 let (counterparty_node_id, channel_id) = if let Some(m) = monitors.get(&funding_txo) {
573                         (m.monitor.get_counterparty_node_id(), m.monitor.channel_id())
574                 } else {
575                         (None, ChannelId::v1_from_funding_outpoint(funding_txo))
576                 };
577                 self.pending_monitor_events.lock().unwrap().push((funding_txo, channel_id, vec![MonitorEvent::Completed {
578                         funding_txo,
579                         channel_id,
580                         monitor_update_id,
581                 }], counterparty_node_id));
582                 self.event_notifier.notify();
583         }
584
585         #[cfg(any(test, feature = "_test_utils"))]
586         pub fn get_and_clear_pending_events(&self) -> Vec<events::Event> {
587                 use crate::events::EventsProvider;
588                 let events = core::cell::RefCell::new(Vec::new());
589                 let event_handler = |event: events::Event| events.borrow_mut().push(event);
590                 self.process_pending_events(&event_handler);
591                 events.into_inner()
592         }
593
594         /// Processes any events asynchronously in the order they were generated since the last call
595         /// using the given event handler.
596         ///
597         /// See the trait-level documentation of [`EventsProvider`] for requirements.
598         ///
599         /// [`EventsProvider`]: crate::events::EventsProvider
600         pub async fn process_pending_events_async<Future: core::future::Future, H: Fn(Event) -> Future>(
601                 &self, handler: H
602         ) {
603                 // Sadly we can't hold the monitors read lock through an async call. Thus we have to do a
604                 // crazy dance to process a monitor's events then only remove them once we've done so.
605                 let mons_to_process = self.monitors.read().unwrap().keys().cloned().collect::<Vec<_>>();
606                 for funding_txo in mons_to_process {
607                         let mut ev;
608                         super::channelmonitor::process_events_body!(
609                                 self.monitors.read().unwrap().get(&funding_txo).map(|m| &m.monitor), ev, handler(ev).await);
610                 }
611         }
612
613         /// Gets a [`Future`] that completes when an event is available either via
614         /// [`chain::Watch::release_pending_monitor_events`] or
615         /// [`EventsProvider::process_pending_events`].
616         ///
617         /// Note that callbacks registered on the [`Future`] MUST NOT call back into this
618         /// [`ChainMonitor`] and should instead register actions to be taken later.
619         ///
620         /// [`EventsProvider::process_pending_events`]: crate::events::EventsProvider::process_pending_events
621         pub fn get_update_future(&self) -> Future {
622                 self.event_notifier.get_future()
623         }
624
625         /// Triggers rebroadcasts/fee-bumps of pending claims from a force-closed channel. This is
626         /// crucial in preventing certain classes of pinning attacks, detecting substantial mempool
627         /// feerate changes between blocks, and ensuring reliability if broadcasting fails. We recommend
628         /// invoking this every 30 seconds, or lower if running in an environment with spotty
629         /// connections, like on mobile.
630         pub fn rebroadcast_pending_claims(&self) {
631                 let monitors = self.monitors.read().unwrap();
632                 for (_, monitor_holder) in &*monitors {
633                         monitor_holder.monitor.rebroadcast_pending_claims(
634                                 &*self.broadcaster, &*self.fee_estimator, &self.logger
635                         )
636                 }
637         }
638
639         /// Triggers rebroadcasts of pending claims from force-closed channels after a transaction
640         /// signature generation failure.
641         ///
642         /// `monitor_opt` can be used as a filter to only trigger them for a specific channel monitor.
643         pub fn signer_unblocked(&self, monitor_opt: Option<OutPoint>) {
644                 let monitors = self.monitors.read().unwrap();
645                 if let Some(funding_txo) = monitor_opt {
646                         if let Some(monitor_holder) = monitors.get(&funding_txo) {
647                                 monitor_holder.monitor.signer_unblocked(
648                                         &*self.broadcaster, &*self.fee_estimator, &self.logger
649                                 )
650                         }
651                 } else {
652                         for (_, monitor_holder) in &*monitors {
653                                 monitor_holder.monitor.signer_unblocked(
654                                         &*self.broadcaster, &*self.fee_estimator, &self.logger
655                                 )
656                         }
657                 }
658         }
659 }
660
661 impl<ChannelSigner: WriteableEcdsaChannelSigner, C: Deref, T: Deref, F: Deref, L: Deref, P: Deref>
662 chain::Listen for ChainMonitor<ChannelSigner, C, T, F, L, P>
663 where
664         C::Target: chain::Filter,
665         T::Target: BroadcasterInterface,
666         F::Target: FeeEstimator,
667         L::Target: Logger,
668         P::Target: Persist<ChannelSigner>,
669 {
670         fn filtered_block_connected(&self, header: &Header, txdata: &TransactionData, height: u32) {
671                 log_debug!(self.logger, "New best block {} at height {} provided via block_connected", header.block_hash(), height);
672                 self.process_chain_data(header, Some(height), &txdata, |monitor, txdata| {
673                         monitor.block_connected(
674                                 header, txdata, height, &*self.broadcaster, &*self.fee_estimator, &self.logger)
675                 });
676         }
677
678         fn block_disconnected(&self, header: &Header, height: u32) {
679                 let monitor_states = self.monitors.read().unwrap();
680                 log_debug!(self.logger, "Latest block {} at height {} removed via block_disconnected", header.block_hash(), height);
681                 for monitor_state in monitor_states.values() {
682                         monitor_state.monitor.block_disconnected(
683                                 header, height, &*self.broadcaster, &*self.fee_estimator, &self.logger);
684                 }
685         }
686 }
687
688 impl<ChannelSigner: WriteableEcdsaChannelSigner, C: Deref, T: Deref, F: Deref, L: Deref, P: Deref>
689 chain::Confirm for ChainMonitor<ChannelSigner, C, T, F, L, P>
690 where
691         C::Target: chain::Filter,
692         T::Target: BroadcasterInterface,
693         F::Target: FeeEstimator,
694         L::Target: Logger,
695         P::Target: Persist<ChannelSigner>,
696 {
697         fn transactions_confirmed(&self, header: &Header, txdata: &TransactionData, height: u32) {
698                 log_debug!(self.logger, "{} provided transactions confirmed at height {} in block {}", txdata.len(), height, header.block_hash());
699                 self.process_chain_data(header, None, txdata, |monitor, txdata| {
700                         monitor.transactions_confirmed(
701                                 header, txdata, height, &*self.broadcaster, &*self.fee_estimator, &self.logger)
702                 });
703         }
704
705         fn transaction_unconfirmed(&self, txid: &Txid) {
706                 log_debug!(self.logger, "Transaction {} reorganized out of chain", txid);
707                 let monitor_states = self.monitors.read().unwrap();
708                 for monitor_state in monitor_states.values() {
709                         monitor_state.monitor.transaction_unconfirmed(txid, &*self.broadcaster, &*self.fee_estimator, &self.logger);
710                 }
711         }
712
713         fn best_block_updated(&self, header: &Header, height: u32) {
714                 log_debug!(self.logger, "New best block {} at height {} provided via best_block_updated", header.block_hash(), height);
715                 self.process_chain_data(header, Some(height), &[], |monitor, txdata| {
716                         // While in practice there shouldn't be any recursive calls when given empty txdata,
717                         // it's still possible if a chain::Filter implementation returns a transaction.
718                         debug_assert!(txdata.is_empty());
719                         monitor.best_block_updated(
720                                 header, height, &*self.broadcaster, &*self.fee_estimator, &self.logger
721                         )
722                 });
723         }
724
725         fn get_relevant_txids(&self) -> Vec<(Txid, u32, Option<BlockHash>)> {
726                 let mut txids = Vec::new();
727                 let monitor_states = self.monitors.read().unwrap();
728                 for monitor_state in monitor_states.values() {
729                         txids.append(&mut monitor_state.monitor.get_relevant_txids());
730                 }
731
732                 txids.sort_unstable_by(|a, b| a.0.cmp(&b.0).then(b.1.cmp(&a.1)));
733                 txids.dedup_by_key(|(txid, _, _)| *txid);
734                 txids
735         }
736 }
737
738 impl<ChannelSigner: WriteableEcdsaChannelSigner, C: Deref , T: Deref , F: Deref , L: Deref , P: Deref >
739 chain::Watch<ChannelSigner> for ChainMonitor<ChannelSigner, C, T, F, L, P>
740 where C::Target: chain::Filter,
741             T::Target: BroadcasterInterface,
742             F::Target: FeeEstimator,
743             L::Target: Logger,
744             P::Target: Persist<ChannelSigner>,
745 {
746         fn watch_channel(&self, funding_outpoint: OutPoint, monitor: ChannelMonitor<ChannelSigner>) -> Result<ChannelMonitorUpdateStatus, ()> {
747                 let logger = WithChannelMonitor::from(&self.logger, &monitor);
748                 let mut monitors = self.monitors.write().unwrap();
749                 let entry = match monitors.entry(funding_outpoint) {
750                         hash_map::Entry::Occupied(_) => {
751                                 log_error!(logger, "Failed to add new channel data: channel monitor for given outpoint is already present");
752                                 return Err(());
753                         },
754                         hash_map::Entry::Vacant(e) => e,
755                 };
756                 log_trace!(logger, "Got new ChannelMonitor for channel {}", log_funding_info!(monitor));
757                 let update_id = MonitorUpdateId::from_new_monitor(&monitor);
758                 let mut pending_monitor_updates = Vec::new();
759                 let persist_res = self.persister.persist_new_channel(funding_outpoint, &monitor, update_id);
760                 match persist_res {
761                         ChannelMonitorUpdateStatus::InProgress => {
762                                 log_info!(logger, "Persistence of new ChannelMonitor for channel {} in progress", log_funding_info!(monitor));
763                                 pending_monitor_updates.push(update_id);
764                         },
765                         ChannelMonitorUpdateStatus::Completed => {
766                                 log_info!(logger, "Persistence of new ChannelMonitor for channel {} completed", log_funding_info!(monitor));
767                         },
768                         ChannelMonitorUpdateStatus::UnrecoverableError => {
769                                 let err_str = "ChannelMonitor[Update] persistence failed unrecoverably. This indicates we cannot continue normal operation and must shut down.";
770                                 log_error!(logger, "{}", err_str);
771                                 panic!("{}", err_str);
772                         },
773                 }
774                 if let Some(ref chain_source) = self.chain_source {
775                         monitor.load_outputs_to_watch(chain_source , &self.logger);
776                 }
777                 entry.insert(MonitorHolder {
778                         monitor,
779                         pending_monitor_updates: Mutex::new(pending_monitor_updates),
780                         last_chain_persist_height: AtomicUsize::new(self.highest_chain_height.load(Ordering::Acquire)),
781                 });
782                 Ok(persist_res)
783         }
784
785         fn update_channel(&self, funding_txo: OutPoint, update: &ChannelMonitorUpdate) -> ChannelMonitorUpdateStatus {
786                 // `ChannelMonitorUpdate`'s `channel_id` is `None` prior to 0.0.121 and all channels in those
787                 // versions are V1-established. For 0.0.121+ the `channel_id` fields is always `Some`.
788                 let channel_id = update.channel_id.unwrap_or(ChannelId::v1_from_funding_outpoint(funding_txo));
789                 // Update the monitor that watches the channel referred to by the given outpoint.
790                 let monitors = self.monitors.read().unwrap();
791                 match monitors.get(&funding_txo) {
792                         None => {
793                                 let logger = WithContext::from(&self.logger, update.counterparty_node_id, Some(channel_id));
794                                 log_error!(logger, "Failed to update channel monitor: no such monitor registered");
795
796                                 // We should never ever trigger this from within ChannelManager. Technically a
797                                 // user could use this object with some proxying in between which makes this
798                                 // possible, but in tests and fuzzing, this should be a panic.
799                                 #[cfg(debug_assertions)]
800                                 panic!("ChannelManager generated a channel update for a channel that was not yet registered!");
801                                 #[cfg(not(debug_assertions))]
802                                 ChannelMonitorUpdateStatus::InProgress
803                         },
804                         Some(monitor_state) => {
805                                 let monitor = &monitor_state.monitor;
806                                 let logger = WithChannelMonitor::from(&self.logger, &monitor);
807                                 log_trace!(logger, "Updating ChannelMonitor for channel {}", log_funding_info!(monitor));
808                                 let update_res = monitor.update_monitor(update, &self.broadcaster, &self.fee_estimator, &self.logger);
809
810                                 let update_id = MonitorUpdateId::from_monitor_update(update);
811                                 let mut pending_monitor_updates = monitor_state.pending_monitor_updates.lock().unwrap();
812                                 let persist_res = if update_res.is_err() {
813                                         // Even if updating the monitor returns an error, the monitor's state will
814                                         // still be changed. Therefore, we should persist the updated monitor despite the error.
815                                         // We don't want to persist a `monitor_update` which results in a failure to apply later
816                                         // while reading `channel_monitor` with updates from storage. Instead, we should persist
817                                         // the entire `channel_monitor` here.
818                                         log_warn!(logger, "Failed to update ChannelMonitor for channel {}. Going ahead and persisting the entire ChannelMonitor", log_funding_info!(monitor));
819                                         self.persister.update_persisted_channel(funding_txo, None, monitor, update_id)
820                                 } else {
821                                         self.persister.update_persisted_channel(funding_txo, Some(update), monitor, update_id)
822                                 };
823                                 match persist_res {
824                                         ChannelMonitorUpdateStatus::InProgress => {
825                                                 pending_monitor_updates.push(update_id);
826                                                 log_debug!(logger, "Persistence of ChannelMonitorUpdate for channel {} in progress", log_funding_info!(monitor));
827                                         },
828                                         ChannelMonitorUpdateStatus::Completed => {
829                                                 log_debug!(logger, "Persistence of ChannelMonitorUpdate for channel {} completed", log_funding_info!(monitor));
830                                         },
831                                         ChannelMonitorUpdateStatus::UnrecoverableError => {
832                                                 // Take the monitors lock for writing so that we poison it and any future
833                                                 // operations going forward fail immediately.
834                                                 core::mem::drop(pending_monitor_updates);
835                                                 core::mem::drop(monitors);
836                                                 let _poison = self.monitors.write().unwrap();
837                                                 let err_str = "ChannelMonitor[Update] persistence failed unrecoverably. This indicates we cannot continue normal operation and must shut down.";
838                                                 log_error!(logger, "{}", err_str);
839                                                 panic!("{}", err_str);
840                                         },
841                                 }
842                                 if update_res.is_err() {
843                                         ChannelMonitorUpdateStatus::InProgress
844                                 } else {
845                                         persist_res
846                                 }
847                         }
848                 }
849         }
850
851         fn release_pending_monitor_events(&self) -> Vec<(OutPoint, ChannelId, Vec<MonitorEvent>, Option<PublicKey>)> {
852                 let mut pending_monitor_events = self.pending_monitor_events.lock().unwrap().split_off(0);
853                 for monitor_state in self.monitors.read().unwrap().values() {
854                         let logger = WithChannelMonitor::from(&self.logger, &monitor_state.monitor);
855                         let is_pending_monitor_update = monitor_state.has_pending_chainsync_updates(&monitor_state.pending_monitor_updates.lock().unwrap());
856                         if !is_pending_monitor_update || monitor_state.last_chain_persist_height.load(Ordering::Acquire) + LATENCY_GRACE_PERIOD_BLOCKS as usize <= self.highest_chain_height.load(Ordering::Acquire) {
857                                 if is_pending_monitor_update {
858                                         log_error!(logger, "A ChannelMonitor sync took longer than {} blocks to complete.", LATENCY_GRACE_PERIOD_BLOCKS);
859                                         log_error!(logger, "   To avoid funds-loss, we are allowing monitor updates to be released.");
860                                         log_error!(logger, "   This may cause duplicate payment events to be generated.");
861                                 }
862                                 let monitor_events = monitor_state.monitor.get_and_clear_pending_monitor_events();
863                                 if monitor_events.len() > 0 {
864                                         let monitor_outpoint = monitor_state.monitor.get_funding_txo().0;
865                                         let monitor_channel_id = monitor_state.monitor.channel_id();
866                                         let counterparty_node_id = monitor_state.monitor.get_counterparty_node_id();
867                                         pending_monitor_events.push((monitor_outpoint, monitor_channel_id, monitor_events, counterparty_node_id));
868                                 }
869                         }
870                 }
871                 pending_monitor_events
872         }
873 }
874
875 impl<ChannelSigner: WriteableEcdsaChannelSigner, C: Deref, T: Deref, F: Deref, L: Deref, P: Deref> events::EventsProvider for ChainMonitor<ChannelSigner, C, T, F, L, P>
876         where C::Target: chain::Filter,
877               T::Target: BroadcasterInterface,
878               F::Target: FeeEstimator,
879               L::Target: Logger,
880               P::Target: Persist<ChannelSigner>,
881 {
882         /// Processes [`SpendableOutputs`] events produced from each [`ChannelMonitor`] upon maturity.
883         ///
884         /// For channels featuring anchor outputs, this method will also process [`BumpTransaction`]
885         /// events produced from each [`ChannelMonitor`] while there is a balance to claim onchain
886         /// within each channel. As the confirmation of a commitment transaction may be critical to the
887         /// safety of funds, we recommend invoking this every 30 seconds, or lower if running in an
888         /// environment with spotty connections, like on mobile.
889         ///
890         /// An [`EventHandler`] may safely call back to the provider, though this shouldn't be needed in
891         /// order to handle these events.
892         ///
893         /// [`SpendableOutputs`]: events::Event::SpendableOutputs
894         /// [`BumpTransaction`]: events::Event::BumpTransaction
895         fn process_pending_events<H: Deref>(&self, handler: H) where H::Target: EventHandler {
896                 for monitor_state in self.monitors.read().unwrap().values() {
897                         monitor_state.monitor.process_pending_events(&handler);
898                 }
899         }
900 }
901
902 #[cfg(test)]
903 mod tests {
904         use crate::check_added_monitors;
905         use crate::{expect_payment_claimed, expect_payment_path_successful, get_event_msg};
906         use crate::{get_htlc_update_msgs, get_local_commitment_txn, get_revoke_commit_msgs, get_route_and_payment_hash, unwrap_send_err};
907         use crate::chain::{ChannelMonitorUpdateStatus, Confirm, Watch};
908         use crate::chain::channelmonitor::LATENCY_GRACE_PERIOD_BLOCKS;
909         use crate::events::{Event, MessageSendEvent, MessageSendEventsProvider};
910         use crate::ln::channelmanager::{PaymentSendFailure, PaymentId, RecipientOnionFields};
911         use crate::ln::functional_test_utils::*;
912         use crate::ln::msgs::ChannelMessageHandler;
913         use crate::util::errors::APIError;
914
915         #[test]
916         fn test_async_ooo_offchain_updates() {
917                 // Test that if we have multiple offchain updates being persisted and they complete
918                 // out-of-order, the ChainMonitor waits until all have completed before informing the
919                 // ChannelManager.
920                 let chanmon_cfgs = create_chanmon_cfgs(2);
921                 let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
922                 let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
923                 let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
924                 create_announced_chan_between_nodes(&nodes, 0, 1);
925
926                 // Route two payments to be claimed at the same time.
927                 let (payment_preimage_1, payment_hash_1, ..) = route_payment(&nodes[0], &[&nodes[1]], 1_000_000);
928                 let (payment_preimage_2, payment_hash_2, ..) = route_payment(&nodes[0], &[&nodes[1]], 1_000_000);
929
930                 chanmon_cfgs[1].persister.offchain_monitor_updates.lock().unwrap().clear();
931                 chanmon_cfgs[1].persister.set_update_ret(ChannelMonitorUpdateStatus::InProgress);
932                 chanmon_cfgs[1].persister.set_update_ret(ChannelMonitorUpdateStatus::InProgress);
933
934                 nodes[1].node.claim_funds(payment_preimage_1);
935                 check_added_monitors!(nodes[1], 1);
936                 nodes[1].node.claim_funds(payment_preimage_2);
937                 check_added_monitors!(nodes[1], 1);
938
939                 let persistences = chanmon_cfgs[1].persister.offchain_monitor_updates.lock().unwrap().clone();
940                 assert_eq!(persistences.len(), 1);
941                 let (funding_txo, updates) = persistences.iter().next().unwrap();
942                 assert_eq!(updates.len(), 2);
943
944                 // Note that updates is a HashMap so the ordering here is actually random. This shouldn't
945                 // fail either way but if it fails intermittently it's depending on the ordering of updates.
946                 let mut update_iter = updates.iter();
947                 let next_update = update_iter.next().unwrap().clone();
948                 // Should contain next_update when pending updates listed.
949                 #[cfg(not(c_bindings))]
950                 assert!(nodes[1].chain_monitor.chain_monitor.list_pending_monitor_updates().get(funding_txo)
951                         .unwrap().contains(&next_update));
952                 #[cfg(c_bindings)]
953                 assert!(nodes[1].chain_monitor.chain_monitor.list_pending_monitor_updates().iter()
954                         .find(|(txo, _)| txo == funding_txo).unwrap().1.contains(&next_update));
955                 nodes[1].chain_monitor.chain_monitor.channel_monitor_updated(*funding_txo, next_update.clone()).unwrap();
956                 // Should not contain the previously pending next_update when pending updates listed.
957                 #[cfg(not(c_bindings))]
958                 assert!(!nodes[1].chain_monitor.chain_monitor.list_pending_monitor_updates().get(funding_txo)
959                         .unwrap().contains(&next_update));
960                 #[cfg(c_bindings)]
961                 assert!(!nodes[1].chain_monitor.chain_monitor.list_pending_monitor_updates().iter()
962                         .find(|(txo, _)| txo == funding_txo).unwrap().1.contains(&next_update));
963                 assert!(nodes[1].chain_monitor.release_pending_monitor_events().is_empty());
964                 assert!(nodes[1].node.get_and_clear_pending_msg_events().is_empty());
965                 assert!(nodes[1].node.get_and_clear_pending_events().is_empty());
966                 nodes[1].chain_monitor.chain_monitor.channel_monitor_updated(*funding_txo, update_iter.next().unwrap().clone()).unwrap();
967
968                 let claim_events = nodes[1].node.get_and_clear_pending_events();
969                 assert_eq!(claim_events.len(), 2);
970                 match claim_events[0] {
971                         Event::PaymentClaimed { ref payment_hash, amount_msat: 1_000_000, .. } => {
972                                 assert_eq!(payment_hash_1, *payment_hash);
973                         },
974                         _ => panic!("Unexpected event"),
975                 }
976                 match claim_events[1] {
977                         Event::PaymentClaimed { ref payment_hash, amount_msat: 1_000_000, .. } => {
978                                 assert_eq!(payment_hash_2, *payment_hash);
979                         },
980                         _ => panic!("Unexpected event"),
981                 }
982
983                 // Now manually walk the commitment signed dance - because we claimed two payments
984                 // back-to-back it doesn't fit into the neat walk commitment_signed_dance does.
985
986                 let updates = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
987                 nodes[0].node.handle_update_fulfill_htlc(&nodes[1].node.get_our_node_id(), &updates.update_fulfill_htlcs[0]);
988                 expect_payment_sent(&nodes[0], payment_preimage_1, None, false, false);
989                 nodes[0].node.handle_commitment_signed(&nodes[1].node.get_our_node_id(), &updates.commitment_signed);
990                 check_added_monitors!(nodes[0], 1);
991                 let (as_first_raa, as_first_update) = get_revoke_commit_msgs!(nodes[0], nodes[1].node.get_our_node_id());
992
993                 nodes[1].node.handle_revoke_and_ack(&nodes[0].node.get_our_node_id(), &as_first_raa);
994                 check_added_monitors!(nodes[1], 1);
995                 let bs_second_updates = get_htlc_update_msgs!(nodes[1], nodes[0].node.get_our_node_id());
996                 nodes[1].node.handle_commitment_signed(&nodes[0].node.get_our_node_id(), &as_first_update);
997                 check_added_monitors!(nodes[1], 1);
998                 let bs_first_raa = get_event_msg!(nodes[1], MessageSendEvent::SendRevokeAndACK, nodes[0].node.get_our_node_id());
999
1000                 nodes[0].node.handle_update_fulfill_htlc(&nodes[1].node.get_our_node_id(), &bs_second_updates.update_fulfill_htlcs[0]);
1001                 expect_payment_sent(&nodes[0], payment_preimage_2, None, false, false);
1002                 nodes[0].node.handle_commitment_signed(&nodes[1].node.get_our_node_id(), &bs_second_updates.commitment_signed);
1003                 check_added_monitors!(nodes[0], 1);
1004                 nodes[0].node.handle_revoke_and_ack(&nodes[1].node.get_our_node_id(), &bs_first_raa);
1005                 expect_payment_path_successful!(nodes[0]);
1006                 check_added_monitors!(nodes[0], 1);
1007                 let (as_second_raa, as_second_update) = get_revoke_commit_msgs!(nodes[0], nodes[1].node.get_our_node_id());
1008
1009                 nodes[1].node.handle_revoke_and_ack(&nodes[0].node.get_our_node_id(), &as_second_raa);
1010                 check_added_monitors!(nodes[1], 1);
1011                 nodes[1].node.handle_commitment_signed(&nodes[0].node.get_our_node_id(), &as_second_update);
1012                 check_added_monitors!(nodes[1], 1);
1013                 let bs_second_raa = get_event_msg!(nodes[1], MessageSendEvent::SendRevokeAndACK, nodes[0].node.get_our_node_id());
1014
1015                 nodes[0].node.handle_revoke_and_ack(&nodes[1].node.get_our_node_id(), &bs_second_raa);
1016                 expect_payment_path_successful!(nodes[0]);
1017                 check_added_monitors!(nodes[0], 1);
1018         }
1019
1020         fn do_chainsync_pauses_events(block_timeout: bool) {
1021                 // When a chainsync monitor update occurs, any MonitorUpdates should be held before being
1022                 // passed upstream to a `ChannelManager` via `Watch::release_pending_monitor_events`. This
1023                 // tests that behavior, as well as some ways it might go wrong.
1024                 let chanmon_cfgs = create_chanmon_cfgs(2);
1025                 let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
1026                 let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
1027                 let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
1028                 let channel = create_announced_chan_between_nodes(&nodes, 0, 1);
1029
1030                 // Get a route for later and rebalance the channel somewhat
1031                 send_payment(&nodes[0], &[&nodes[1]], 10_000_000);
1032                 let (route, second_payment_hash, _, second_payment_secret) = get_route_and_payment_hash!(nodes[0], nodes[1], 100_000);
1033
1034                 // First route a payment that we will claim on chain and give the recipient the preimage.
1035                 let (payment_preimage, payment_hash, ..) = route_payment(&nodes[0], &[&nodes[1]], 1_000_000);
1036                 nodes[1].node.claim_funds(payment_preimage);
1037                 expect_payment_claimed!(nodes[1], payment_hash, 1_000_000);
1038                 nodes[1].node.get_and_clear_pending_msg_events();
1039                 check_added_monitors!(nodes[1], 1);
1040                 let remote_txn = get_local_commitment_txn!(nodes[1], channel.2);
1041                 assert_eq!(remote_txn.len(), 2);
1042
1043                 // Temp-fail the block connection which will hold the channel-closed event
1044                 chanmon_cfgs[0].persister.chain_sync_monitor_persistences.lock().unwrap().clear();
1045                 chanmon_cfgs[0].persister.set_update_ret(ChannelMonitorUpdateStatus::InProgress);
1046
1047                 // Connect B's commitment transaction, but only to the ChainMonitor/ChannelMonitor. The
1048                 // channel is now closed, but the ChannelManager doesn't know that yet.
1049                 let new_header = create_dummy_header(nodes[0].best_block_info().0, 0);
1050                 nodes[0].chain_monitor.chain_monitor.transactions_confirmed(&new_header,
1051                         &[(0, &remote_txn[0]), (1, &remote_txn[1])], nodes[0].best_block_info().1 + 1);
1052                 assert!(nodes[0].chain_monitor.release_pending_monitor_events().is_empty());
1053                 nodes[0].chain_monitor.chain_monitor.best_block_updated(&new_header, nodes[0].best_block_info().1 + 1);
1054                 assert!(nodes[0].chain_monitor.release_pending_monitor_events().is_empty());
1055
1056                 // If the ChannelManager tries to update the channel, however, the ChainMonitor will pass
1057                 // the update through to the ChannelMonitor which will refuse it (as the channel is closed).
1058                 chanmon_cfgs[0].persister.set_update_ret(ChannelMonitorUpdateStatus::Completed);
1059                 unwrap_send_err!(nodes[0].node.send_payment_with_route(&route, second_payment_hash,
1060                                 RecipientOnionFields::secret_only(second_payment_secret), PaymentId(second_payment_hash.0)
1061                         ), false, APIError::MonitorUpdateInProgress, {});
1062                 check_added_monitors!(nodes[0], 1);
1063
1064                 // However, as the ChainMonitor is still waiting for the original persistence to complete,
1065                 // it won't yet release the MonitorEvents.
1066                 assert!(nodes[0].chain_monitor.release_pending_monitor_events().is_empty());
1067
1068                 if block_timeout {
1069                         // After three blocks, pending MontiorEvents should be released either way.
1070                         let latest_header = create_dummy_header(nodes[0].best_block_info().0, 0);
1071                         nodes[0].chain_monitor.chain_monitor.best_block_updated(&latest_header, nodes[0].best_block_info().1 + LATENCY_GRACE_PERIOD_BLOCKS);
1072                 } else {
1073                         let persistences = chanmon_cfgs[0].persister.chain_sync_monitor_persistences.lock().unwrap().clone();
1074                         for (funding_outpoint, update_ids) in persistences {
1075                                 for update_id in update_ids {
1076                                         nodes[0].chain_monitor.chain_monitor.channel_monitor_updated(funding_outpoint, update_id).unwrap();
1077                                 }
1078                         }
1079                 }
1080
1081                 expect_payment_sent(&nodes[0], payment_preimage, None, true, false);
1082         }
1083
1084         #[test]
1085         fn chainsync_pauses_events() {
1086                 do_chainsync_pauses_events(false);
1087                 do_chainsync_pauses_events(true);
1088         }
1089
1090         #[test]
1091         #[cfg(feature = "std")]
1092         fn update_during_chainsync_poisons_channel() {
1093                 let chanmon_cfgs = create_chanmon_cfgs(2);
1094                 let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
1095                 let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
1096                 let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
1097                 create_announced_chan_between_nodes(&nodes, 0, 1);
1098
1099                 chanmon_cfgs[0].persister.chain_sync_monitor_persistences.lock().unwrap().clear();
1100                 chanmon_cfgs[0].persister.set_update_ret(ChannelMonitorUpdateStatus::UnrecoverableError);
1101
1102                 assert!(std::panic::catch_unwind(|| {
1103                         // Returning an UnrecoverableError should always panic immediately
1104                         connect_blocks(&nodes[0], 1);
1105                 }).is_err());
1106                 assert!(std::panic::catch_unwind(|| {
1107                         // ...and also poison our locks causing later use to panic as well
1108                         core::mem::drop(nodes);
1109                 }).is_err());
1110         }
1111 }