//! update [`ChannelMonitor`]s accordingly. If any on-chain events need further processing, it will
//! make those available as [`MonitorEvent`]s to be consumed.
//!
-//! `ChainMonitor` is parameterized by an optional chain source, which must implement the
+//! [`ChainMonitor`] is parameterized by an optional chain source, which must implement the
//! [`chain::Filter`] trait. This provides a mechanism to signal new relevant outputs back to light
//! clients, such that transactions spending those outputs are included in block data.
//!
-//! `ChainMonitor` may be used directly to monitor channels locally or as a part of a distributed
-//! setup to monitor channels remotely. In the latter case, a custom `chain::Watch` implementation
+//! [`ChainMonitor`] may be used directly to monitor channels locally or as a part of a distributed
+//! setup to monitor channels remotely. In the latter case, a custom [`chain::Watch`] implementation
//! would be responsible for routing each update to a remote server and for retrieving monitor
-//! events. The remote server would make use of `ChainMonitor` for block processing and for
-//! servicing `ChannelMonitor` updates from the client.
-//!
-//! [`ChainMonitor`]: struct.ChainMonitor.html
-//! [`chain::Filter`]: ../trait.Filter.html
-//! [`chain::Watch`]: ../trait.Watch.html
-//! [`ChannelMonitor`]: ../channelmonitor/struct.ChannelMonitor.html
-//! [`MonitorEvent`]: ../channelmonitor/enum.MonitorEvent.html
+//! events. The remote server would make use of [`ChainMonitor`] for block processing and for
+//! servicing [`ChannelMonitor`] updates from the client.
use bitcoin::blockdata::block::{Block, BlockHeader};
+use bitcoin::hash_types::Txid;
use chain;
-use chain::Filter;
+use chain::{ChannelMonitorUpdateErr, Filter, WatchedOutput};
use chain::chaininterface::{BroadcasterInterface, FeeEstimator};
-use chain::channelmonitor;
-use chain::channelmonitor::{ChannelMonitor, ChannelMonitorUpdate, ChannelMonitorUpdateErr, MonitorEvent, Persist};
+use chain::channelmonitor::{ChannelMonitor, ChannelMonitorUpdate, Balance, MonitorEvent, TransactionOutputs, LATENCY_GRACE_PERIOD_BLOCKS};
use chain::transaction::{OutPoint, TransactionData};
use chain::keysinterface::Sign;
+use util::atomic_counter::AtomicCounter;
use util::logger::Logger;
+use util::errors::APIError;
use util::events;
-use util::events::Event;
+use util::events::EventHandler;
+use ln::channelmanager::ChannelDetails;
+
+use prelude::*;
+use sync::{RwLock, RwLockReadGuard, Mutex, MutexGuard};
+use core::ops::Deref;
+use core::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
+
+#[derive(Clone, Copy, Hash, PartialEq, Eq)]
+/// A specific update's ID stored in a `MonitorUpdateId`, separated out to make the contents
+/// entirely opaque.
+enum UpdateOrigin {
+ /// An update that was generated by the `ChannelManager` (via our `chain::Watch`
+ /// implementation). This corresponds to an actual [`ChannelMonitorUpdate::update_id`] field
+ /// and [`ChannelMonitor::get_latest_update_id`].
+ OffChain(u64),
+ /// An update that was generated during blockchain processing. The ID here is specific to the
+ /// generating [`ChainMonitor`] and does *not* correspond to any on-disk IDs.
+ ChainSync(u64),
+}
+
+/// An opaque identifier describing a specific [`Persist`] method call.
+#[derive(Clone, Copy, Hash, PartialEq, Eq)]
+pub struct MonitorUpdateId {
+ contents: UpdateOrigin,
+}
+
+impl MonitorUpdateId {
+ pub(crate) fn from_monitor_update(update: &ChannelMonitorUpdate) -> Self {
+ Self { contents: UpdateOrigin::OffChain(update.update_id) }
+ }
+ pub(crate) fn from_new_monitor<ChannelSigner: Sign>(monitor: &ChannelMonitor<ChannelSigner>) -> Self {
+ Self { contents: UpdateOrigin::OffChain(monitor.get_latest_update_id()) }
+ }
+}
+
+/// `Persist` defines behavior for persisting channel monitors: this could mean
+/// writing once to disk, and/or uploading to one or more backup services.
+///
+/// Each method can return three possible values:
+/// * If persistence (including any relevant `fsync()` calls) happens immediately, the
+/// implementation should return `Ok(())`, indicating normal channel operation should continue.
+/// * If persistence happens asynchronously, implementations should first ensure the
+/// [`ChannelMonitor`] or [`ChannelMonitorUpdate`] are written durably to disk, and then return
+/// `Err(ChannelMonitorUpdateErr::TemporaryFailure)` while the update continues in the
+/// background. Once the update completes, [`ChainMonitor::channel_monitor_updated`] should be
+/// called with the corresponding [`MonitorUpdateId`].
+///
+/// Note that unlike the direct [`chain::Watch`] interface,
+/// [`ChainMonitor::channel_monitor_updated`] must be called once for *each* update which occurs.
+///
+/// * If persistence fails for some reason, implementations should return
+/// `Err(ChannelMonitorUpdateErr::PermanentFailure)`, in which case the channel will likely be
+/// closed without broadcasting the latest state. See
+/// [`ChannelMonitorUpdateErr::PermanentFailure`] for more details.
+pub trait Persist<ChannelSigner: Sign> {
+ /// Persist a new channel's data in response to a [`chain::Watch::watch_channel`] call. This is
+ /// called by [`ChannelManager`] for new channels, or may be called directly, e.g. on startup.
+ ///
+ /// The data can be stored any way you want, but the identifier provided by LDK is the
+ /// channel's outpoint (and it is up to you to maintain a correct mapping between the outpoint
+ /// and the stored channel data). Note that you **must** persist every new monitor to disk.
+ ///
+ /// The `update_id` is used to identify this call to [`ChainMonitor::channel_monitor_updated`],
+ /// if you return [`ChannelMonitorUpdateErr::TemporaryFailure`].
+ ///
+ /// See [`Writeable::write`] on [`ChannelMonitor`] for writing out a `ChannelMonitor`
+ /// and [`ChannelMonitorUpdateErr`] for requirements when returning errors.
+ ///
+ /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
+ /// [`Writeable::write`]: crate::util::ser::Writeable::write
+ fn persist_new_channel(&self, channel_id: OutPoint, data: &ChannelMonitor<ChannelSigner>, update_id: MonitorUpdateId) -> Result<(), ChannelMonitorUpdateErr>;
-use std::collections::{HashMap, hash_map};
-use std::sync::RwLock;
-use std::ops::Deref;
+ /// Update one channel's data. The provided [`ChannelMonitor`] has already applied the given
+ /// update.
+ ///
+ /// Note that on every update, you **must** persist either the [`ChannelMonitorUpdate`] or the
+ /// updated monitor itself to disk/backups. See the [`Persist`] trait documentation for more
+ /// details.
+ ///
+ /// During blockchain synchronization operations, this may be called with no
+ /// [`ChannelMonitorUpdate`], in which case the full [`ChannelMonitor`] needs to be persisted.
+ /// Note that after the full [`ChannelMonitor`] is persisted any previous
+ /// [`ChannelMonitorUpdate`]s which were persisted should be discarded - they can no longer be
+ /// applied to the persisted [`ChannelMonitor`] as they were already applied.
+ ///
+ /// If an implementer chooses to persist the updates only, they need to make
+ /// sure that all the updates are applied to the `ChannelMonitors` *before*
+ /// the set of channel monitors is given to the `ChannelManager`
+ /// deserialization routine. See [`ChannelMonitor::update_monitor`] for
+ /// applying a monitor update to a monitor. If full `ChannelMonitors` are
+ /// persisted, then there is no need to persist individual updates.
+ ///
+ /// Note that there could be a performance tradeoff between persisting complete
+ /// channel monitors on every update vs. persisting only updates and applying
+ /// them in batches. The size of each monitor grows `O(number of state updates)`
+ /// whereas updates are small and `O(1)`.
+ ///
+ /// The `update_id` is used to identify this call to [`ChainMonitor::channel_monitor_updated`],
+ /// if you return [`ChannelMonitorUpdateErr::TemporaryFailure`].
+ ///
+ /// See [`Writeable::write`] on [`ChannelMonitor`] for writing out a `ChannelMonitor`,
+ /// [`Writeable::write`] on [`ChannelMonitorUpdate`] for writing out an update, and
+ /// [`ChannelMonitorUpdateErr`] for requirements when returning errors.
+ ///
+ /// [`Writeable::write`]: crate::util::ser::Writeable::write
+ fn update_persisted_channel(&self, channel_id: OutPoint, update: &Option<ChannelMonitorUpdate>, data: &ChannelMonitor<ChannelSigner>, update_id: MonitorUpdateId) -> Result<(), ChannelMonitorUpdateErr>;
+}
+
+struct MonitorHolder<ChannelSigner: Sign> {
+ monitor: ChannelMonitor<ChannelSigner>,
+ /// The full set of pending monitor updates for this Channel.
+ ///
+ /// Note that this lock must be held during updates to prevent a race where we call
+ /// update_persisted_channel, the user returns a TemporaryFailure, and then calls
+ /// channel_monitor_updated immediately, racing our insertion of the pending update into the
+ /// contained Vec.
+ ///
+ /// Beyond the synchronization of updates themselves, we cannot handle user events until after
+ /// any chain updates have been stored on disk. Thus, we scan this list when returning updates
+ /// to the ChannelManager, refusing to return any updates for a ChannelMonitor which is still
+ /// being persisted fully to disk after a chain update.
+ ///
+ /// This avoids the possibility of handling, e.g. an on-chain claim, generating a claim monitor
+ /// event, resulting in the relevant ChannelManager generating a PaymentSent event and dropping
+ /// the pending payment entry, and then reloading before the monitor is persisted, resulting in
+ /// the ChannelManager re-adding the same payment entry, before the same block is replayed,
+ /// resulting in a duplicate PaymentSent event.
+ pending_monitor_updates: Mutex<Vec<MonitorUpdateId>>,
+ /// When the user returns a PermanentFailure error from an update_persisted_channel call during
+ /// block processing, we inform the ChannelManager that the channel should be closed
+ /// asynchronously. In order to ensure no further changes happen before the ChannelManager has
+ /// processed the closure event, we set this to true and return PermanentFailure for any other
+ /// chain::Watch events.
+ channel_perm_failed: AtomicBool,
+ /// The last block height at which no [`UpdateOrigin::ChainSync`] monitor updates were present
+ /// in `pending_monitor_updates`.
+ /// If it's been more than [`LATENCY_GRACE_PERIOD_BLOCKS`] since we started waiting on a chain
+ /// sync event, we let monitor events return to `ChannelManager` because we cannot hold them up
+ /// forever or we'll end up with HTLC preimages waiting to feed back into an upstream channel
+ /// forever, risking funds loss.
+ last_chain_persist_height: AtomicUsize,
+}
+
+impl<ChannelSigner: Sign> MonitorHolder<ChannelSigner> {
+ fn has_pending_offchain_updates(&self, pending_monitor_updates_lock: &MutexGuard<Vec<MonitorUpdateId>>) -> bool {
+ pending_monitor_updates_lock.iter().any(|update_id|
+ if let UpdateOrigin::OffChain(_) = update_id.contents { true } else { false })
+ }
+ fn has_pending_chainsync_updates(&self, pending_monitor_updates_lock: &MutexGuard<Vec<MonitorUpdateId>>) -> bool {
+ pending_monitor_updates_lock.iter().any(|update_id|
+ if let UpdateOrigin::ChainSync(_) = update_id.contents { true } else { false })
+ }
+}
+
+/// A read-only reference to a current ChannelMonitor.
+///
+/// Note that this holds a mutex in [`ChainMonitor`] and may block other events until it is
+/// released.
+pub struct LockedChannelMonitor<'a, ChannelSigner: Sign> {
+ lock: RwLockReadGuard<'a, HashMap<OutPoint, MonitorHolder<ChannelSigner>>>,
+ funding_txo: OutPoint,
+}
+
+impl<ChannelSigner: Sign> Deref for LockedChannelMonitor<'_, ChannelSigner> {
+ type Target = ChannelMonitor<ChannelSigner>;
+ fn deref(&self) -> &ChannelMonitor<ChannelSigner> {
+ &self.lock.get(&self.funding_txo).expect("Checked at construction").monitor
+ }
+}
/// An implementation of [`chain::Watch`] for monitoring channels.
///
/// or used independently to monitor channels remotely. See the [module-level documentation] for
/// details.
///
-/// [`chain::Watch`]: ../trait.Watch.html
-/// [`ChannelManager`]: ../../ln/channelmanager/struct.ChannelManager.html
-/// [module-level documentation]: index.html
+/// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
+/// [module-level documentation]: crate::chain::chainmonitor
pub struct ChainMonitor<ChannelSigner: Sign, C: Deref, T: Deref, F: Deref, L: Deref, P: Deref>
where C::Target: chain::Filter,
T::Target: BroadcasterInterface,
F::Target: FeeEstimator,
L::Target: Logger,
- P::Target: channelmonitor::Persist<ChannelSigner>,
+ P::Target: Persist<ChannelSigner>,
{
- /// The monitors
- pub monitors: RwLock<HashMap<OutPoint, ChannelMonitor<ChannelSigner>>>,
+ monitors: RwLock<HashMap<OutPoint, MonitorHolder<ChannelSigner>>>,
+ /// When we generate a [`MonitorUpdateId`] for a chain-event monitor persistence, we need a
+ /// unique ID, which we calculate by simply getting the next value from this counter. Note that
+ /// the ID is never persisted so it's ok that they reset on restart.
+ sync_persistence_id: AtomicCounter,
chain_source: Option<C>,
broadcaster: T,
logger: L,
fee_estimator: F,
persister: P,
+ /// "User-provided" (ie persistence-completion/-failed) [`MonitorEvent`]s. These came directly
+ /// from the user and not from a [`ChannelMonitor`].
+ pending_monitor_events: Mutex<Vec<MonitorEvent>>,
+ /// The best block height seen, used as a proxy for the passage of time.
+ highest_chain_height: AtomicUsize,
}
impl<ChannelSigner: Sign, C: Deref, T: Deref, F: Deref, L: Deref, P: Deref> ChainMonitor<ChannelSigner, C, T, F, L, P>
T::Target: BroadcasterInterface,
F::Target: FeeEstimator,
L::Target: Logger,
- P::Target: channelmonitor::Persist<ChannelSigner>,
+ P::Target: Persist<ChannelSigner>,
{
/// Dispatches to per-channel monitors, which are responsible for updating their on-chain view
- /// of a channel and reacting accordingly based on transactions in the connected block. See
+ /// of a channel and reacting accordingly based on transactions in the given chain data. See
/// [`ChannelMonitor::block_connected`] for details. Any HTLCs that were resolved on chain will
/// be returned by [`chain::Watch::release_pending_monitor_events`].
///
/// descendants of such transactions. It is not necessary to re-fetch the block to obtain
/// updated `txdata`.
///
- /// [`ChannelMonitor::block_connected`]: ../channelmonitor/struct.ChannelMonitor.html#method.block_connected
- /// [`chain::Watch::release_pending_monitor_events`]: ../trait.Watch.html#tymethod.release_pending_monitor_events
- /// [`chain::Filter`]: ../trait.Filter.html
- pub fn block_connected(&self, header: &BlockHeader, txdata: &TransactionData, height: u32) {
- let monitors = self.monitors.read().unwrap();
- for monitor in monitors.values() {
- let mut txn_outputs = monitor.block_connected(header, txdata, height, &*self.broadcaster, &*self.fee_estimator, &*self.logger);
+ /// Calls which represent a new blockchain tip height should set `best_height`.
+ fn process_chain_data<FN>(&self, header: &BlockHeader, best_height: Option<u32>, txdata: &TransactionData, process: FN)
+ where
+ FN: Fn(&ChannelMonitor<ChannelSigner>, &TransactionData) -> Vec<TransactionOutputs>
+ {
+ let mut dependent_txdata = Vec::new();
+ {
+ let monitor_states = self.monitors.write().unwrap();
+ if let Some(height) = best_height {
+ // If the best block height is being updated, update highest_chain_height under the
+ // monitors write lock.
+ let old_height = self.highest_chain_height.load(Ordering::Acquire);
+ let new_height = height as usize;
+ if new_height > old_height {
+ self.highest_chain_height.store(new_height, Ordering::Release);
+ }
+ }
+
+ for (funding_outpoint, monitor_state) in monitor_states.iter() {
+ let monitor = &monitor_state.monitor;
+ let mut txn_outputs;
+ {
+ txn_outputs = process(monitor, txdata);
+ let update_id = MonitorUpdateId {
+ contents: UpdateOrigin::ChainSync(self.sync_persistence_id.get_increment()),
+ };
+ let mut pending_monitor_updates = monitor_state.pending_monitor_updates.lock().unwrap();
+ if let Some(height) = best_height {
+ if !monitor_state.has_pending_chainsync_updates(&pending_monitor_updates) {
+ // If there are not ChainSync persists awaiting completion, go ahead and
+ // set last_chain_persist_height here - we wouldn't want the first
+ // TemporaryFailure to always immediately be considered "overly delayed".
+ monitor_state.last_chain_persist_height.store(height as usize, Ordering::Release);
+ }
+ }
+
+ log_trace!(self.logger, "Syncing Channel Monitor for channel {}", log_funding_info!(monitor));
+ match self.persister.update_persisted_channel(*funding_outpoint, &None, monitor, update_id) {
+ Ok(()) =>
+ log_trace!(self.logger, "Finished syncing Channel Monitor for channel {}", log_funding_info!(monitor)),
+ Err(ChannelMonitorUpdateErr::PermanentFailure) => {
+ monitor_state.channel_perm_failed.store(true, Ordering::Release);
+ self.pending_monitor_events.lock().unwrap().push(MonitorEvent::UpdateFailed(*funding_outpoint));
+ },
+ Err(ChannelMonitorUpdateErr::TemporaryFailure) => {
+ log_debug!(self.logger, "Channel Monitor sync for channel {} in progress, holding events until completion!", log_funding_info!(monitor));
+ pending_monitor_updates.push(update_id);
+ },
+ }
+ }
- if let Some(ref chain_source) = self.chain_source {
- for (txid, outputs) in txn_outputs.drain(..) {
- for (idx, output) in outputs.iter() {
- chain_source.register_output(&OutPoint { txid, index: *idx as u16 }, &output.script_pubkey);
+ // Register any new outputs with the chain source for filtering, storing any dependent
+ // transactions from within the block that previously had not been included in txdata.
+ if let Some(ref chain_source) = self.chain_source {
+ let block_hash = header.block_hash();
+ for (txid, mut outputs) in txn_outputs.drain(..) {
+ for (idx, output) in outputs.drain(..) {
+ // Register any new outputs with the chain source for filtering and recurse
+ // if it indicates that there are dependent transactions within the block
+ // that had not been previously included in txdata.
+ let output = WatchedOutput {
+ block_hash: Some(block_hash),
+ outpoint: OutPoint { txid, index: idx as u16 },
+ script_pubkey: output.script_pubkey,
+ };
+ if let Some(tx) = chain_source.register_output(output) {
+ dependent_txdata.push(tx);
+ }
+ }
}
}
}
}
- }
- /// Dispatches to per-channel monitors, which are responsible for updating their on-chain view
- /// of a channel based on the disconnected block. See [`ChannelMonitor::block_disconnected`] for
- /// details.
- ///
- /// [`ChannelMonitor::block_disconnected`]: ../channelmonitor/struct.ChannelMonitor.html#method.block_disconnected
- pub fn block_disconnected(&self, header: &BlockHeader, disconnected_height: u32) {
- let monitors = self.monitors.read().unwrap();
- for monitor in monitors.values() {
- monitor.block_disconnected(header, disconnected_height, &*self.broadcaster, &*self.fee_estimator, &*self.logger);
+ // Recursively call for any dependent transactions that were identified by the chain source.
+ if !dependent_txdata.is_empty() {
+ dependent_txdata.sort_unstable_by_key(|(index, _tx)| *index);
+ dependent_txdata.dedup_by_key(|(index, _tx)| *index);
+ let txdata: Vec<_> = dependent_txdata.iter().map(|(index, tx)| (*index, tx)).collect();
+ self.process_chain_data(header, None, &txdata, process); // We skip the best height the second go-around
}
}
/// pre-filter blocks or only fetch blocks matching a compact filter. Otherwise, clients may
/// always need to fetch full blocks absent another means for determining which blocks contain
/// transactions relevant to the watched channels.
- ///
- /// [`chain::Filter`]: ../trait.Filter.html
pub fn new(chain_source: Option<C>, broadcaster: T, logger: L, feeest: F, persister: P) -> Self {
Self {
monitors: RwLock::new(HashMap::new()),
+ sync_persistence_id: AtomicCounter::new(),
chain_source,
broadcaster,
logger,
fee_estimator: feeest,
persister,
+ pending_monitor_events: Mutex::new(Vec::new()),
+ highest_chain_height: AtomicUsize::new(0),
+ }
+ }
+
+ /// Gets the balances in the contained [`ChannelMonitor`]s which are claimable on-chain or
+ /// claims which are awaiting confirmation.
+ ///
+ /// Includes the balances from each [`ChannelMonitor`] *except* those included in
+ /// `ignored_channels`, allowing you to filter out balances from channels which are still open
+ /// (and whose balance should likely be pulled from the [`ChannelDetails`]).
+ ///
+ /// See [`ChannelMonitor::get_claimable_balances`] for more details on the exact criteria for
+ /// inclusion in the return value.
+ pub fn get_claimable_balances(&self, ignored_channels: &[&ChannelDetails]) -> Vec<Balance> {
+ let mut ret = Vec::new();
+ let monitor_states = self.monitors.read().unwrap();
+ for (_, monitor_state) in monitor_states.iter().filter(|(funding_outpoint, _)| {
+ for chan in ignored_channels {
+ if chan.funding_txo.as_ref() == Some(funding_outpoint) {
+ return false;
+ }
+ }
+ true
+ }) {
+ ret.append(&mut monitor_state.monitor.get_claimable_balances());
+ }
+ ret
+ }
+
+ /// Gets the [`LockedChannelMonitor`] for a given funding outpoint, returning an `Err` if no
+ /// such [`ChannelMonitor`] is currently being monitored for.
+ ///
+ /// Note that the result holds a mutex over our monitor set, and should not be held
+ /// indefinitely.
+ pub fn get_monitor(&self, funding_txo: OutPoint) -> Result<LockedChannelMonitor<'_, ChannelSigner>, ()> {
+ let lock = self.monitors.read().unwrap();
+ if lock.get(&funding_txo).is_some() {
+ Ok(LockedChannelMonitor { lock, funding_txo })
+ } else {
+ Err(())
+ }
+ }
+
+ /// Lists the funding outpoint of each [`ChannelMonitor`] being monitored.
+ ///
+ /// Note that [`ChannelMonitor`]s are not removed when a channel is closed as they are always
+ /// monitoring for on-chain state resolutions.
+ pub fn list_monitors(&self) -> Vec<OutPoint> {
+ self.monitors.read().unwrap().keys().map(|outpoint| *outpoint).collect()
+ }
+
+ #[cfg(test)]
+ pub fn remove_monitor(&self, funding_txo: &OutPoint) -> ChannelMonitor<ChannelSigner> {
+ self.monitors.write().unwrap().remove(funding_txo).unwrap().monitor
+ }
+
+ /// Indicates the persistence of a [`ChannelMonitor`] has completed after
+ /// [`ChannelMonitorUpdateErr::TemporaryFailure`] was returned from an update operation.
+ ///
+ /// Thus, the anticipated use is, at a high level:
+ /// 1) This [`ChainMonitor`] calls [`Persist::update_persisted_channel`] which stores the
+ /// update to disk and begins updating any remote (e.g. watchtower/backup) copies,
+ /// returning [`ChannelMonitorUpdateErr::TemporaryFailure`],
+ /// 2) once all remote copies are updated, you call this function with the
+ /// `completed_update_id` that completed, and once all pending updates have completed the
+ /// channel will be re-enabled.
+ // Note that we re-enable only after `UpdateOrigin::OffChain` updates complete, we don't
+ // care about `UpdateOrigin::ChainSync` updates for the channel state being updated. We
+ // only care about `UpdateOrigin::ChainSync` for returning `MonitorEvent`s.
+ ///
+ /// Returns an [`APIError::APIMisuseError`] if `funding_txo` does not match any currently
+ /// registered [`ChannelMonitor`]s.
+ pub fn channel_monitor_updated(&self, funding_txo: OutPoint, completed_update_id: MonitorUpdateId) -> Result<(), APIError> {
+ let monitors = self.monitors.read().unwrap();
+ let monitor_data = if let Some(mon) = monitors.get(&funding_txo) { mon } else {
+ return Err(APIError::APIMisuseError { err: format!("No ChannelMonitor matching funding outpoint {:?} found", funding_txo) });
+ };
+ let mut pending_monitor_updates = monitor_data.pending_monitor_updates.lock().unwrap();
+ pending_monitor_updates.retain(|update_id| *update_id != completed_update_id);
+
+ match completed_update_id {
+ MonitorUpdateId { contents: UpdateOrigin::OffChain(_) } => {
+ // Note that we only check for `UpdateOrigin::OffChain` failures here - if
+ // we're being told that a `UpdateOrigin::OffChain` monitor update completed,
+ // we only care about ensuring we don't tell the `ChannelManager` to restore
+ // the channel to normal operation until all `UpdateOrigin::OffChain` updates
+ // complete.
+ // If there's some `UpdateOrigin::ChainSync` update still pending that's okay
+ // - we can still update our channel state, just as long as we don't return
+ // `MonitorEvent`s from the monitor back to the `ChannelManager` until they
+ // complete.
+ let monitor_is_pending_updates = monitor_data.has_pending_offchain_updates(&pending_monitor_updates);
+ if monitor_is_pending_updates || monitor_data.channel_perm_failed.load(Ordering::Acquire) {
+ // If there are still monitor updates pending (or an old monitor update
+ // finished after a later one perm-failed), we cannot yet construct an
+ // UpdateCompleted event.
+ return Ok(());
+ }
+ self.pending_monitor_events.lock().unwrap().push(MonitorEvent::UpdateCompleted {
+ funding_txo,
+ monitor_update_id: monitor_data.monitor.get_latest_update_id(),
+ });
+ },
+ MonitorUpdateId { contents: UpdateOrigin::ChainSync(_) } => {
+ if !monitor_data.has_pending_chainsync_updates(&pending_monitor_updates) {
+ monitor_data.last_chain_persist_height.store(self.highest_chain_height.load(Ordering::Acquire), Ordering::Release);
+ // The next time release_pending_monitor_events is called, any events for this
+ // ChannelMonitor will be returned.
+ }
+ },
}
+ Ok(())
+ }
+
+ /// This wrapper avoids having to update some of our tests for now as they assume the direct
+ /// chain::Watch API wherein we mark a monitor fully-updated by just calling
+ /// channel_monitor_updated once with the highest ID.
+ #[cfg(any(test, feature = "fuzztarget"))]
+ pub fn force_channel_monitor_updated(&self, funding_txo: OutPoint, monitor_update_id: u64) {
+ self.pending_monitor_events.lock().unwrap().push(MonitorEvent::UpdateCompleted {
+ funding_txo,
+ monitor_update_id,
+ });
+ }
+
+ #[cfg(any(test, feature = "fuzztarget", feature = "_test_utils"))]
+ pub fn get_and_clear_pending_events(&self) -> Vec<events::Event> {
+ use util::events::EventsProvider;
+ let events = core::cell::RefCell::new(Vec::new());
+ let event_handler = |event: &events::Event| events.borrow_mut().push(event.clone());
+ self.process_pending_events(&event_handler);
+ events.into_inner()
}
}
-impl<ChannelSigner: Sign, C: Deref + Send + Sync, T: Deref + Send + Sync, F: Deref + Send + Sync, L: Deref + Send + Sync, P: Deref + Send + Sync>
+impl<ChannelSigner: Sign, C: Deref, T: Deref, F: Deref, L: Deref, P: Deref>
chain::Listen for ChainMonitor<ChannelSigner, C, T, F, L, P>
where
- ChannelSigner: Sign,
C::Target: chain::Filter,
T::Target: BroadcasterInterface,
F::Target: FeeEstimator,
L::Target: Logger,
- P::Target: channelmonitor::Persist<ChannelSigner>,
+ P::Target: Persist<ChannelSigner>,
{
fn block_connected(&self, block: &Block, height: u32) {
+ let header = &block.header;
let txdata: Vec<_> = block.txdata.iter().enumerate().collect();
- ChainMonitor::block_connected(self, &block.header, &txdata, height);
+ log_debug!(self.logger, "New best block {} at height {} provided via block_connected", header.block_hash(), height);
+ self.process_chain_data(header, Some(height), &txdata, |monitor, txdata| {
+ monitor.block_connected(
+ header, txdata, height, &*self.broadcaster, &*self.fee_estimator, &*self.logger)
+ });
}
fn block_disconnected(&self, header: &BlockHeader, height: u32) {
- ChainMonitor::block_disconnected(self, header, height);
+ let monitor_states = self.monitors.read().unwrap();
+ log_debug!(self.logger, "Latest block {} at height {} removed via block_disconnected", header.block_hash(), height);
+ for monitor_state in monitor_states.values() {
+ monitor_state.monitor.block_disconnected(
+ header, height, &*self.broadcaster, &*self.fee_estimator, &*self.logger);
+ }
}
}
-impl<ChannelSigner: Sign, C: Deref + Sync + Send, T: Deref + Sync + Send, F: Deref + Sync + Send, L: Deref + Sync + Send, P: Deref + Sync + Send>
+impl<ChannelSigner: Sign, C: Deref, T: Deref, F: Deref, L: Deref, P: Deref>
+chain::Confirm for ChainMonitor<ChannelSigner, C, T, F, L, P>
+where
+ C::Target: chain::Filter,
+ T::Target: BroadcasterInterface,
+ F::Target: FeeEstimator,
+ L::Target: Logger,
+ P::Target: Persist<ChannelSigner>,
+{
+ fn transactions_confirmed(&self, header: &BlockHeader, txdata: &TransactionData, height: u32) {
+ log_debug!(self.logger, "{} provided transactions confirmed at height {} in block {}", txdata.len(), height, header.block_hash());
+ self.process_chain_data(header, None, txdata, |monitor, txdata| {
+ monitor.transactions_confirmed(
+ header, txdata, height, &*self.broadcaster, &*self.fee_estimator, &*self.logger)
+ });
+ }
+
+ fn transaction_unconfirmed(&self, txid: &Txid) {
+ log_debug!(self.logger, "Transaction {} reorganized out of chain", txid);
+ let monitor_states = self.monitors.read().unwrap();
+ for monitor_state in monitor_states.values() {
+ monitor_state.monitor.transaction_unconfirmed(txid, &*self.broadcaster, &*self.fee_estimator, &*self.logger);
+ }
+ }
+
+ fn best_block_updated(&self, header: &BlockHeader, height: u32) {
+ log_debug!(self.logger, "New best block {} at height {} provided via best_block_updated", header.block_hash(), height);
+ self.process_chain_data(header, Some(height), &[], |monitor, txdata| {
+ // While in practice there shouldn't be any recursive calls when given empty txdata,
+ // it's still possible if a chain::Filter implementation returns a transaction.
+ debug_assert!(txdata.is_empty());
+ monitor.best_block_updated(
+ header, height, &*self.broadcaster, &*self.fee_estimator, &*self.logger)
+ });
+ }
+
+ fn get_relevant_txids(&self) -> Vec<Txid> {
+ let mut txids = Vec::new();
+ let monitor_states = self.monitors.read().unwrap();
+ for monitor_state in monitor_states.values() {
+ txids.append(&mut monitor_state.monitor.get_relevant_txids());
+ }
+
+ txids.sort_unstable();
+ txids.dedup();
+ txids
+ }
+}
+
+impl<ChannelSigner: Sign, C: Deref , T: Deref , F: Deref , L: Deref , P: Deref >
chain::Watch<ChannelSigner> for ChainMonitor<ChannelSigner, C, T, F, L, P>
where C::Target: chain::Filter,
T::Target: BroadcasterInterface,
F::Target: FeeEstimator,
L::Target: Logger,
- P::Target: channelmonitor::Persist<ChannelSigner>,
+ P::Target: Persist<ChannelSigner>,
{
/// Adds the monitor that watches the channel referred to by the given outpoint.
///
///
/// Note that we persist the given `ChannelMonitor` while holding the `ChainMonitor`
/// monitors lock.
- ///
- /// [`chain::Filter`]: ../trait.Filter.html
fn watch_channel(&self, funding_outpoint: OutPoint, monitor: ChannelMonitor<ChannelSigner>) -> Result<(), ChannelMonitorUpdateErr> {
let mut monitors = self.monitors.write().unwrap();
let entry = match monitors.entry(funding_outpoint) {
return Err(ChannelMonitorUpdateErr::PermanentFailure)},
hash_map::Entry::Vacant(e) => e,
};
- if let Err(e) = self.persister.persist_new_channel(funding_outpoint, &monitor) {
- log_error!(self.logger, "Failed to persist new channel data");
- return Err(e);
+ log_trace!(self.logger, "Got new ChannelMonitor for channel {}", log_funding_info!(monitor));
+ let update_id = MonitorUpdateId::from_new_monitor(&monitor);
+ let mut pending_monitor_updates = Vec::new();
+ let persist_res = self.persister.persist_new_channel(funding_outpoint, &monitor, update_id);
+ if persist_res.is_err() {
+ log_error!(self.logger, "Failed to persist new ChannelMonitor for channel {}: {:?}", log_funding_info!(monitor), persist_res);
+ } else {
+ log_trace!(self.logger, "Finished persisting new ChannelMonitor for channel {}", log_funding_info!(monitor));
}
- {
- let funding_txo = monitor.get_funding_txo();
- log_trace!(self.logger, "Got new Channel Monitor for channel {}", log_bytes!(funding_txo.0.to_channel_id()[..]));
-
- if let Some(ref chain_source) = self.chain_source {
- monitor.load_outputs_to_watch(chain_source);
- }
+ if persist_res == Err(ChannelMonitorUpdateErr::PermanentFailure) {
+ return persist_res;
+ } else if persist_res.is_err() {
+ pending_monitor_updates.push(update_id);
}
- entry.insert(monitor);
- Ok(())
+ if let Some(ref chain_source) = self.chain_source {
+ monitor.load_outputs_to_watch(chain_source);
+ }
+ entry.insert(MonitorHolder {
+ monitor,
+ pending_monitor_updates: Mutex::new(pending_monitor_updates),
+ channel_perm_failed: AtomicBool::new(false),
+ last_chain_persist_height: AtomicUsize::new(self.highest_chain_height.load(Ordering::Acquire)),
+ });
+ persist_res
}
/// Note that we persist the given `ChannelMonitor` update while holding the
#[cfg(not(any(test, feature = "fuzztarget")))]
Err(ChannelMonitorUpdateErr::PermanentFailure)
},
- Some(monitor) => {
- log_trace!(self.logger, "Updating Channel Monitor for channel {}", log_funding_info!(monitor));
+ Some(monitor_state) => {
+ let monitor = &monitor_state.monitor;
+ log_trace!(self.logger, "Updating ChannelMonitor for channel {}", log_funding_info!(monitor));
let update_res = monitor.update_monitor(&update, &self.broadcaster, &self.fee_estimator, &self.logger);
if let Err(e) = &update_res {
- log_error!(self.logger, "Failed to update channel monitor: {:?}", e);
+ log_error!(self.logger, "Failed to update ChannelMonitor for channel {}: {:?}", log_funding_info!(monitor), e);
}
// Even if updating the monitor returns an error, the monitor's state will
// still be changed. So, persist the updated monitor despite the error.
- let persist_res = self.persister.update_persisted_channel(funding_txo, &update, monitor);
- if let Err(ref e) = persist_res {
- log_error!(self.logger, "Failed to persist channel monitor update: {:?}", e);
+ let update_id = MonitorUpdateId::from_monitor_update(&update);
+ let mut pending_monitor_updates = monitor_state.pending_monitor_updates.lock().unwrap();
+ let persist_res = self.persister.update_persisted_channel(funding_txo, &Some(update), monitor, update_id);
+ if let Err(e) = persist_res {
+ if e == ChannelMonitorUpdateErr::TemporaryFailure {
+ pending_monitor_updates.push(update_id);
+ } else {
+ monitor_state.channel_perm_failed.store(true, Ordering::Release);
+ }
+ log_error!(self.logger, "Failed to persist ChannelMonitor update for channel {}: {:?}", log_funding_info!(monitor), e);
+ } else {
+ log_trace!(self.logger, "Finished persisting ChannelMonitor update for channel {}", log_funding_info!(monitor));
}
if update_res.is_err() {
Err(ChannelMonitorUpdateErr::PermanentFailure)
+ } else if monitor_state.channel_perm_failed.load(Ordering::Acquire) {
+ Err(ChannelMonitorUpdateErr::PermanentFailure)
} else {
persist_res
}
}
fn release_pending_monitor_events(&self) -> Vec<MonitorEvent> {
- let mut pending_monitor_events = Vec::new();
- for monitor in self.monitors.read().unwrap().values() {
- pending_monitor_events.append(&mut monitor.get_and_clear_pending_monitor_events());
+ let mut pending_monitor_events = self.pending_monitor_events.lock().unwrap().split_off(0);
+ for monitor_state in self.monitors.read().unwrap().values() {
+ let is_pending_monitor_update = monitor_state.has_pending_chainsync_updates(&monitor_state.pending_monitor_updates.lock().unwrap());
+ 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)
+ {
+ log_info!(self.logger, "A Channel Monitor sync is still in progress, refusing to provide monitor events!");
+ } else {
+ if monitor_state.channel_perm_failed.load(Ordering::Acquire) {
+ // If a `UpdateOrigin::ChainSync` persistence failed with `PermanantFailure`,
+ // we don't really know if the latest `ChannelMonitor` state is on disk or not.
+ // We're supposed to hold monitor updates until the latest state is on disk to
+ // avoid duplicate events, but the user told us persistence is screw-y and may
+ // not complete. We can't hold events forever because we may learn some payment
+ // preimage, so instead we just log and hope the user complied with the
+ // `PermanentFailure` requirements of having at least the local-disk copy
+ // updated.
+ log_info!(self.logger, "A Channel Monitor sync returned PermanentFailure. Returning monitor events but duplicate events may appear after reload!");
+ }
+ if is_pending_monitor_update {
+ log_error!(self.logger, "A ChannelMonitor sync took longer than {} blocks to complete.", LATENCY_GRACE_PERIOD_BLOCKS);
+ log_error!(self.logger, " To avoid funds-loss, we are allowing monitor updates to be released.");
+ log_error!(self.logger, " This may cause duplicate payment events to be generated.");
+ }
+ pending_monitor_events.append(&mut monitor_state.monitor.get_and_clear_pending_monitor_events());
+ }
}
pending_monitor_events
}
T::Target: BroadcasterInterface,
F::Target: FeeEstimator,
L::Target: Logger,
- P::Target: channelmonitor::Persist<ChannelSigner>,
+ P::Target: Persist<ChannelSigner>,
{
- fn get_and_clear_pending_events(&self) -> Vec<Event> {
+ /// Processes [`SpendableOutputs`] events produced from each [`ChannelMonitor`] upon maturity.
+ ///
+ /// An [`EventHandler`] may safely call back to the provider, though this shouldn't be needed in
+ /// order to handle these events.
+ ///
+ /// [`SpendableOutputs`]: events::Event::SpendableOutputs
+ fn process_pending_events<H: Deref>(&self, handler: H) where H::Target: EventHandler {
let mut pending_events = Vec::new();
- for monitor in self.monitors.read().unwrap().values() {
- pending_events.append(&mut monitor.get_and_clear_pending_events());
+ for monitor_state in self.monitors.read().unwrap().values() {
+ pending_events.append(&mut monitor_state.monitor.get_and_clear_pending_events());
+ }
+ for event in pending_events.drain(..) {
+ handler.handle_event(&event);
}
- pending_events
+ }
+}
+
+#[cfg(test)]
+mod tests {
+ use ::{check_added_monitors, get_local_commitment_txn};
+ use ln::features::InitFeatures;
+ use ln::functional_test_utils::*;
+ use util::events::MessageSendEventsProvider;
+ use util::test_utils::{OnRegisterOutput, TxOutReference};
+
+ /// Tests that in-block dependent transactions are processed by `block_connected` when not
+ /// included in `txdata` but returned by [`chain::Filter::register_output`]. For instance,
+ /// a (non-anchor) commitment transaction's HTLC output may be spent in the same block as the
+ /// commitment transaction itself. An Electrum client may filter the commitment transaction but
+ /// needs to return the HTLC transaction so it can be processed.
+ #[test]
+ fn connect_block_checks_dependent_transactions() {
+ let chanmon_cfgs = create_chanmon_cfgs(2);
+ let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
+ let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
+ let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
+ let channel = create_announced_chan_between_nodes(
+ &nodes, 0, 1, InitFeatures::known(), InitFeatures::known());
+
+ // Send a payment, saving nodes[0]'s revoked commitment and HTLC-Timeout transactions.
+ let (commitment_tx, htlc_tx) = {
+ let payment_preimage = route_payment(&nodes[0], &vec!(&nodes[1])[..], 5_000_000).0;
+ let mut txn = get_local_commitment_txn!(nodes[0], channel.2);
+ claim_payment(&nodes[0], &vec!(&nodes[1])[..], payment_preimage);
+
+ assert_eq!(txn.len(), 2);
+ (txn.remove(0), txn.remove(0))
+ };
+
+ // Set expectations on nodes[1]'s chain source to return dependent transactions.
+ let htlc_output = TxOutReference(commitment_tx.clone(), 0);
+ let to_local_output = TxOutReference(commitment_tx.clone(), 1);
+ let htlc_timeout_output = TxOutReference(htlc_tx.clone(), 0);
+ nodes[1].chain_source
+ .expect(OnRegisterOutput { with: htlc_output, returns: Some((1, htlc_tx)) })
+ .expect(OnRegisterOutput { with: to_local_output, returns: None })
+ .expect(OnRegisterOutput { with: htlc_timeout_output, returns: None });
+
+ // Notify nodes[1] that nodes[0]'s revoked commitment transaction was mined. The chain
+ // source should return the dependent HTLC transaction when the HTLC output is registered.
+ mine_transaction(&nodes[1], &commitment_tx);
+
+ // Clean up so uninteresting assertions don't fail.
+ check_added_monitors!(nodes[1], 1);
+ nodes[1].node.get_and_clear_pending_msg_events();
+ nodes[1].node.get_and_clear_pending_events();
}
}
projects / rust-lightning / blobdiff