--- /dev/null
+// This file is Copyright its original authors, visible in version control
+// history.
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
+// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// You may not use this file except in accordance with one or both of these
+// licenses.
+
+//! Logic to connect off-chain channel management with on-chain transaction monitoring.
+//!
+//! [`ChainMonitor`] is an implementation of [`chain::Watch`] used both to process blocks and to
+//! 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
+//! [`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
+//! 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
+
+use bitcoin::blockdata::block::BlockHeader;
+
+use chain;
+use chain::Filter;
+use chain::chaininterface::{BroadcasterInterface, FeeEstimator};
+use chain::channelmonitor::{ChannelMonitor, ChannelMonitorUpdate, ChannelMonitorUpdateErr, MonitorEvent, MonitorUpdateError};
+use chain::transaction::{OutPoint, TransactionData};
+use chain::keysinterface::ChannelKeys;
+use util::logger::Logger;
+use util::events;
+use util::events::Event;
+
+use std::collections::{HashMap, hash_map};
+use std::sync::Mutex;
+use std::ops::Deref;
+
+/// An implementation of [`chain::Watch`] for monitoring channels.
+///
+/// Connected and disconnected blocks must be provided to `ChainMonitor` as documented by
+/// [`chain::Watch`]. May be used in conjunction with [`ChannelManager`] to monitor channels locally
+/// 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
+pub struct ChainMonitor<ChanSigner: ChannelKeys, C: Deref, T: Deref, F: Deref, L: Deref>
+ where C::Target: chain::Filter,
+ T::Target: BroadcasterInterface,
+ F::Target: FeeEstimator,
+ L::Target: Logger,
+{
+ /// The monitors
+ pub monitors: Mutex<HashMap<OutPoint, ChannelMonitor<ChanSigner>>>,
+ chain_source: Option<C>,
+ broadcaster: T,
+ logger: L,
+ fee_estimator: F
+}
+
+impl<ChanSigner: ChannelKeys, C: Deref, T: Deref, F: Deref, L: Deref> ChainMonitor<ChanSigner, C, T, F, L>
+ where C::Target: chain::Filter,
+ T::Target: BroadcasterInterface,
+ F::Target: FeeEstimator,
+ L::Target: Logger,
+{
+ /// 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
+ /// [`ChannelMonitor::block_connected`] for details. Any HTLCs that were resolved on chain will
+ /// be returned by [`chain::Watch::release_pending_monitor_events`].
+ ///
+ /// Calls back to [`chain::Filter`] if any monitor indicated new outputs to watch, returning
+ /// `true` if so. Subsequent calls must not exclude any transactions matching the new outputs
+ /// nor any in-block 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) -> bool {
+ let mut has_new_outputs_to_watch = false;
+ {
+ let mut monitors = self.monitors.lock().unwrap();
+ for monitor in monitors.values_mut() {
+ let mut txn_outputs = monitor.block_connected(header, txdata, height, &*self.broadcaster, &*self.fee_estimator, &*self.logger);
+ has_new_outputs_to_watch |= !txn_outputs.is_empty();
+
+ if let Some(ref chain_source) = self.chain_source {
+ for (txid, outputs) in txn_outputs.drain(..) {
+ for (idx, output) in outputs.iter().enumerate() {
+ chain_source.register_output(&OutPoint { txid, index: idx as u16 }, &output.script_pubkey);
+ }
+ }
+ }
+ }
+ }
+ has_new_outputs_to_watch
+ }
+
+ /// 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 mut monitors = self.monitors.lock().unwrap();
+ for monitor in monitors.values_mut() {
+ monitor.block_disconnected(header, disconnected_height, &*self.broadcaster, &*self.fee_estimator, &*self.logger);
+ }
+ }
+
+ /// Creates a new `ChainMonitor` used to watch on-chain activity pertaining to channels.
+ ///
+ /// When an optional chain source implementing [`chain::Filter`] is provided, the chain monitor
+ /// will call back to it indicating transactions and outputs of interest. This allows clients to
+ /// 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) -> Self {
+ Self {
+ monitors: Mutex::new(HashMap::new()),
+ chain_source,
+ broadcaster,
+ logger,
+ fee_estimator: feeest,
+ }
+ }
+
+ /// Adds the monitor that watches the channel referred to by the given outpoint.
+ ///
+ /// Calls back to [`chain::Filter`] with the funding transaction and outputs to watch.
+ ///
+ /// [`chain::Filter`]: ../trait.Filter.html
+ fn add_monitor(&self, outpoint: OutPoint, monitor: ChannelMonitor<ChanSigner>) -> Result<(), MonitorUpdateError> {
+ let mut monitors = self.monitors.lock().unwrap();
+ let entry = match monitors.entry(outpoint) {
+ hash_map::Entry::Occupied(_) => return Err(MonitorUpdateError("Channel monitor for given outpoint is already present")),
+ hash_map::Entry::Vacant(e) => e,
+ };
+ {
+ 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 {
+ chain_source.register_tx(&funding_txo.0.txid, &funding_txo.1);
+ for (txid, outputs) in monitor.get_outputs_to_watch().iter() {
+ for (idx, script_pubkey) in outputs.iter().enumerate() {
+ chain_source.register_output(&OutPoint { txid: *txid, index: idx as u16 }, &script_pubkey);
+ }
+ }
+ }
+ }
+ entry.insert(monitor);
+ Ok(())
+ }
+
+ /// Updates the monitor that watches the channel referred to by the given outpoint.
+ fn update_monitor(&self, outpoint: OutPoint, update: ChannelMonitorUpdate) -> Result<(), MonitorUpdateError> {
+ let mut monitors = self.monitors.lock().unwrap();
+ match monitors.get_mut(&outpoint) {
+ Some(orig_monitor) => {
+ log_trace!(self.logger, "Updating Channel Monitor for channel {}", log_funding_info!(orig_monitor));
+ orig_monitor.update_monitor(update, &self.broadcaster, &self.logger)
+ },
+ None => Err(MonitorUpdateError("No such monitor registered"))
+ }
+ }
+}
+
+impl<ChanSigner: ChannelKeys, C: Deref + Sync + Send, T: Deref + Sync + Send, F: Deref + Sync + Send, L: Deref + Sync + Send> chain::Watch for ChainMonitor<ChanSigner, C, T, F, L>
+ where C::Target: chain::Filter,
+ T::Target: BroadcasterInterface,
+ F::Target: FeeEstimator,
+ L::Target: Logger,
+{
+ type Keys = ChanSigner;
+
+ fn watch_channel(&self, funding_txo: OutPoint, monitor: ChannelMonitor<ChanSigner>) -> Result<(), ChannelMonitorUpdateErr> {
+ match self.add_monitor(funding_txo, monitor) {
+ Ok(_) => Ok(()),
+ Err(_) => Err(ChannelMonitorUpdateErr::PermanentFailure),
+ }
+ }
+
+ fn update_channel(&self, funding_txo: OutPoint, update: ChannelMonitorUpdate) -> Result<(), ChannelMonitorUpdateErr> {
+ match self.update_monitor(funding_txo, update) {
+ Ok(_) => Ok(()),
+ Err(_) => Err(ChannelMonitorUpdateErr::PermanentFailure),
+ }
+ }
+
+ fn release_pending_monitor_events(&self) -> Vec<MonitorEvent> {
+ let mut pending_monitor_events = Vec::new();
+ for chan in self.monitors.lock().unwrap().values_mut() {
+ pending_monitor_events.append(&mut chan.get_and_clear_pending_monitor_events());
+ }
+ pending_monitor_events
+ }
+}
+
+impl<ChanSigner: ChannelKeys, C: Deref, T: Deref, F: Deref, L: Deref> events::EventsProvider for ChainMonitor<ChanSigner, C, T, F, L>
+ where C::Target: chain::Filter,
+ T::Target: BroadcasterInterface,
+ F::Target: FeeEstimator,
+ L::Target: Logger,
+{
+ fn get_and_clear_pending_events(&self) -> Vec<Event> {
+ let mut pending_events = Vec::new();
+ for chan in self.monitors.lock().unwrap().values_mut() {
+ pending_events.append(&mut chan.get_and_clear_pending_events());
+ }
+ pending_events
+ }
+}
projects / rust-lightning / blobdiff