//!
//! ChannelMonitor objects are generated by ChannelManager in response to relevant
//! messages/actions, and MUST be persisted to disk (and, preferably, remotely) before progress can
-//! be made in responding to certain messages, see ManyChannelMonitor for more.
+//! be made in responding to certain messages, see [`chain::Watch`] for more.
//!
//! Note that ChannelMonitors are an important part of the lightning trust model and a copy of the
//! latest ChannelMonitor must always be actively monitoring for chain updates (and no out-of-date
//! ChannelMonitors should do so). Thus, if you're building rust-lightning into an HSM or other
//! security-domain-separated system design, you should consider having multiple paths for
//! ChannelMonitors to get out of the HSM and onto monitoring devices.
+//!
+//! [`chain::Watch`]: ../../chain/trait.Watch.html
use bitcoin::blockdata::block::BlockHeader;
use bitcoin::blockdata::transaction::{TxOut,Transaction};
use ln::chan_utils::{CounterpartyCommitmentSecrets, HTLCOutputInCommitment, HolderCommitmentTransaction, HTLCType};
use ln::channelmanager::{HTLCSource, PaymentPreimage, PaymentHash};
use ln::onchaintx::{OnchainTxHandler, InputDescriptors};
-use chain::chaininterface::{ChainListener, ChainWatchInterface, BroadcasterInterface, FeeEstimator};
+use chain;
+use chain::Filter;
+use chain::chaininterface::{ChainWatchedUtil, BroadcasterInterface, FeeEstimator};
use chain::transaction::OutPoint;
use chain::keysinterface::{SpendableOutputDescriptor, ChannelKeys};
use util::logger::Logger;
use util::{byte_utils, events};
use util::events::Event;
-use std::collections::{HashMap, hash_map};
+use std::collections::{HashMap, HashSet, hash_map};
use std::sync::Mutex;
-use std::{hash,cmp, mem};
+use std::{cmp, mem};
use std::ops::Deref;
use std::io::Error;
TemporaryFailure,
/// Used to indicate no further channel monitor updates will be allowed (eg we've moved on to a
/// different watchtower and cannot update with all watchtowers that were previously informed
- /// of this channel). This will force-close the channel in question (which will generate one
- /// final ChannelMonitorUpdate which must be delivered to at least one ChannelMonitor copy).
+ /// of this channel).
+ ///
+ /// At reception of this error, ChannelManager will force-close the channel and return at
+ /// least a final ChannelMonitorUpdate::ChannelForceClosed which must be delivered to at
+ /// least one ChannelMonitor copy. Revocation secret MUST NOT be released and offchain channel
+ /// update must be rejected.
+ ///
+ /// This failure may also signal a failure to update the local persisted copy of one of
+ /// the channel monitor instance.
///
- /// Should also be used to indicate a failure to update the local persisted copy of the channel
- /// monitor.
+ /// Note that even when you fail a holder commitment transaction update, you must store the
+ /// update to ensure you can claim from it in case of a duplicate copy of this ChannelMonitor
+ /// broadcasts it (e.g distributed channel-monitor deployment)
+ ///
+ /// In case of distributed watchtowers deployment, the new version must be written to disk, as
+ /// state may have been stored but rejected due to a block forcing a commitment broadcast. This
+ /// storage is used to claim outputs of rejected state confirmed onchain by another watchtower,
+ /// lagging behind on block processing.
PermanentFailure,
}
CommitmentTxBroadcasted(OutPoint),
}
-/// Simple structure send back by ManyChannelMonitor in case of HTLC detected onchain from a
-/// forward channel and from which info are needed to update HTLC in a backward channel.
+/// Simple structure sent back by `chain::Watch` when an HTLC from a forward channel is detected on
+/// chain. Used to update the corresponding HTLC in the backward channel. Failing to pass the
+/// preimage claim backward will lead to loss of funds.
+///
+/// [`chain::Watch`]: ../../chain/trait.Watch.html
#[derive(Clone, PartialEq)]
pub struct HTLCUpdate {
pub(super) payment_hash: PaymentHash,
}
impl_writeable!(HTLCUpdate, 0, { payment_hash, payment_preimage, source });
-/// A simple implementation of a ManyChannelMonitor and ChainListener. Can be used to create a
-/// watchtower or watch our own channels.
+/// An implementation of [`chain::Watch`] for monitoring channels.
///
-/// Note that you must provide your own key by which to refer to 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.
///
-/// If you're accepting remote monitors (ie are implementing a watchtower), you must verify that
-/// users cannot overwrite a given channel by providing a duplicate key. ie you should probably
-/// index by a PublicKey which is required to sign any updates.
-///
-/// If you're using this for local monitoring of your own channels, you probably want to use
-/// `OutPoint` as the key, which will give you a ManyChannelMonitor implementation.
-///
-/// (C-not exported) due to an unconstrained generic in `Key`
-pub struct SimpleManyChannelMonitor<Key, ChanSigner: ChannelKeys, T: Deref, F: Deref, L: Deref, C: Deref>
- where T::Target: BroadcasterInterface,
+/// [`chain::Watch`]: ../../chain/trait.Watch.html
+/// [`ChannelManager`]: ../channelmanager/struct.ChannelManager.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,
- C::Target: ChainWatchInterface,
{
/// The monitors
- pub monitors: Mutex<HashMap<Key, ChannelMonitor<ChanSigner>>>,
- chain_monitor: C,
+ pub monitors: Mutex<HashMap<OutPoint, ChannelMonitor<ChanSigner>>>,
+ watch_events: Mutex<WatchEventCache>,
+ chain_source: Option<C>,
broadcaster: T,
logger: L,
fee_estimator: F
}
-impl<Key : Send + cmp::Eq + hash::Hash, ChanSigner: ChannelKeys, T: Deref + Sync + Send, F: Deref + Sync + Send, L: Deref + Sync + Send, C: Deref + Sync + Send>
- ChainListener for SimpleManyChannelMonitor<Key, ChanSigner, T, F, L, C>
- where T::Target: BroadcasterInterface,
+struct WatchEventCache {
+ watched: ChainWatchedUtil,
+ events: Vec<WatchEvent>,
+}
+
+/// An event indicating on-chain activity to watch for pertaining to a channel.
+enum WatchEvent {
+ /// Watch for a transaction with `txid` and having an output with `script_pubkey` as a spending
+ /// condition.
+ WatchTransaction {
+ /// Identifier of the transaction.
+ txid: Txid,
+
+ /// Spending condition for an output of the transaction.
+ script_pubkey: Script,
+ },
+ /// Watch for spends of a transaction output identified by `outpoint` having `script_pubkey` as
+ /// the spending condition.
+ WatchOutput {
+ /// Identifier for the output.
+ outpoint: OutPoint,
+
+ /// Spending condition for the output.
+ script_pubkey: Script,
+ }
+}
+
+impl WatchEventCache {
+ fn new() -> Self {
+ Self {
+ watched: ChainWatchedUtil::new(),
+ events: Vec::new(),
+ }
+ }
+
+ fn watch_tx(&mut self, txid: &Txid, script_pubkey: &Script) {
+ if self.watched.register_tx(txid, script_pubkey) {
+ self.events.push(WatchEvent::WatchTransaction {
+ txid: *txid,
+ script_pubkey: script_pubkey.clone()
+ });
+ }
+ }
+
+ fn watch_output(&mut self, outpoint: (&Txid, usize), script_pubkey: &Script) {
+ let (txid, index) = outpoint;
+ if self.watched.register_outpoint((*txid, index as u32), script_pubkey) {
+ self.events.push(WatchEvent::WatchOutput {
+ outpoint: OutPoint {
+ txid: *txid,
+ index: index as u16,
+ },
+ script_pubkey: script_pubkey.clone(),
+ });
+ }
+ }
+
+ fn flush_events<C: Deref>(&mut self, chain_source: &Option<C>) -> bool where C::Target: chain::Filter {
+ let num_events = self.events.len();
+ match chain_source {
+ &None => self.events.clear(),
+ &Some(ref chain_source) => {
+ for event in self.events.drain(..) {
+ match event {
+ WatchEvent::WatchTransaction { txid, script_pubkey } => {
+ chain_source.register_tx(txid, script_pubkey)
+ },
+ WatchEvent::WatchOutput { outpoint, script_pubkey } => {
+ chain_source.register_output(outpoint, script_pubkey)
+ },
+ }
+ }
+ }
+ }
+ num_events > 0
+ }
+
+ fn filter_block<'a>(&self, txdata: &[(usize, &'a Transaction)]) -> Vec<(usize, &'a Transaction)> {
+ let mut matched_txids = HashSet::new();
+ txdata.iter().filter(|&&(_, tx)| {
+ // A tx matches the filter if it either matches the filter directly (via does_match_tx)
+ // or if it is a descendant of another matched transaction within the same block.
+ let mut matched = self.watched.does_match_tx(tx);
+ for input in tx.input.iter() {
+ if matched || matched_txids.contains(&input.previous_output.txid) {
+ matched = true;
+ break;
+ }
+ }
+ if matched {
+ matched_txids.insert(tx.txid());
+ }
+ matched
+ }).map(|e| *e).collect()
+ }
+}
+
+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,
- C::Target: ChainWatchInterface,
{
- fn block_connected(&self, header: &BlockHeader, height: u32, txn_matched: &[&Transaction], _indexes_of_txn_matched: &[usize]) {
- let block_hash = header.block_hash();
+ /// 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`]: struct.ChannelMonitor.html#method.block_connected
+ /// [`chain::Watch::release_pending_monitor_events`]: ../../chain/trait.Watch.html#tymethod.release_pending_monitor_events
+ /// [`chain::Filter`]: ../../chain/trait.Filter.html
+ pub fn block_connected(&self, header: &BlockHeader, txdata: &[(usize, &Transaction)], height: u32) -> bool {
+ let mut watch_events = self.watch_events.lock().unwrap();
+ let matched_txn = watch_events.filter_block(txdata);
{
let mut monitors = self.monitors.lock().unwrap();
for monitor in monitors.values_mut() {
- let txn_outputs = monitor.block_connected(txn_matched, height, &block_hash, &*self.broadcaster, &*self.fee_estimator, &*self.logger);
+ let txn_outputs = monitor.block_connected(header, &matched_txn, height, &*self.broadcaster, &*self.fee_estimator, &*self.logger);
for (ref txid, ref outputs) in txn_outputs {
for (idx, output) in outputs.iter().enumerate() {
- self.chain_monitor.install_watch_outpoint((txid.clone(), idx as u32), &output.script_pubkey);
+ watch_events.watch_output((txid, idx), &output.script_pubkey);
}
}
}
}
+ watch_events.flush_events(&self.chain_source)
}
- fn block_disconnected(&self, header: &BlockHeader, disconnected_height: u32) {
- let block_hash = header.block_hash();
+ /// 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`]: 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(disconnected_height, &block_hash, &*self.broadcaster, &*self.fee_estimator, &*self.logger);
+ monitor.block_disconnected(header, disconnected_height, &*self.broadcaster, &*self.fee_estimator, &*self.logger);
}
}
}
-impl<Key : Send + cmp::Eq + hash::Hash + 'static, ChanSigner: ChannelKeys, T: Deref, F: Deref, L: Deref, C: Deref> SimpleManyChannelMonitor<Key, ChanSigner, T, F, L, C>
- where T::Target: BroadcasterInterface,
+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,
- C::Target: ChainWatchInterface,
{
- /// Creates a new object which can be used to monitor several channels given the chain
- /// interface with which to register to receive notifications.
- pub fn new(chain_monitor: C, broadcaster: T, logger: L, feeest: F) -> SimpleManyChannelMonitor<Key, ChanSigner, T, F, L, C> {
- let res = SimpleManyChannelMonitor {
+ /// 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`]: ../../chain/trait.Filter.html
+ pub fn new(chain_source: Option<C>, broadcaster: T, logger: L, feeest: F) -> Self {
+ Self {
monitors: Mutex::new(HashMap::new()),
- chain_monitor,
+ watch_events: Mutex::new(WatchEventCache::new()),
+ chain_source,
broadcaster,
logger,
fee_estimator: feeest,
- };
-
- res
+ }
}
- /// Adds or updates the monitor which monitors the channel referred to by the given key.
- pub fn add_monitor_by_key(&self, key: Key, monitor: ChannelMonitor<ChanSigner>) -> Result<(), MonitorUpdateError> {
+ /// 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`]: ../../chain/trait.Filter.html
+ fn add_monitor(&self, outpoint: OutPoint, monitor: ChannelMonitor<ChanSigner>) -> Result<(), MonitorUpdateError> {
+ let mut watch_events = self.watch_events.lock().unwrap();
let mut monitors = self.monitors.lock().unwrap();
- let entry = match monitors.entry(key) {
- hash_map::Entry::Occupied(_) => return Err(MonitorUpdateError("Channel monitor for given key is already present")),
+ 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()[..]));
- self.chain_monitor.install_watch_tx(&funding_txo.0.txid, &funding_txo.1);
- self.chain_monitor.install_watch_outpoint((funding_txo.0.txid, funding_txo.0.index as u32), &funding_txo.1);
+ watch_events.watch_tx(&funding_txo.0.txid, &funding_txo.1);
+ watch_events.watch_output((&funding_txo.0.txid, funding_txo.0.index as usize), &funding_txo.1);
for (txid, outputs) in monitor.get_outputs_to_watch().iter() {
for (idx, script) in outputs.iter().enumerate() {
- self.chain_monitor.install_watch_outpoint((*txid, idx as u32), script);
+ watch_events.watch_output((txid, idx), script);
}
}
}
entry.insert(monitor);
+ watch_events.flush_events(&self.chain_source);
Ok(())
}
- /// Updates the monitor which monitors the channel referred to by the given key.
- pub fn update_monitor_by_key(&self, key: Key, update: ChannelMonitorUpdate) -> Result<(), MonitorUpdateError> {
+ /// 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(&key) {
+ 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)
}
}
-impl<ChanSigner: ChannelKeys, T: Deref + Sync + Send, F: Deref + Sync + Send, L: Deref + Sync + Send, C: Deref + Sync + Send> ManyChannelMonitor for SimpleManyChannelMonitor<OutPoint, ChanSigner, T, F, L, C>
- where T::Target: BroadcasterInterface,
+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,
- C::Target: ChainWatchInterface,
{
type Keys = ChanSigner;
- fn add_monitor(&self, funding_txo: OutPoint, monitor: ChannelMonitor<ChanSigner>) -> Result<(), ChannelMonitorUpdateErr> {
- match self.add_monitor_by_key(funding_txo, monitor) {
+ 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_monitor(&self, funding_txo: OutPoint, update: ChannelMonitorUpdate) -> Result<(), ChannelMonitorUpdateErr> {
- match self.update_monitor_by_key(funding_txo, update) {
+ 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 get_and_clear_pending_monitor_events(&self) -> Vec<MonitorEvent> {
+ 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());
}
}
-impl<Key : Send + cmp::Eq + hash::Hash, ChanSigner: ChannelKeys, T: Deref, F: Deref, L: Deref, C: Deref> events::EventsProvider for SimpleManyChannelMonitor<Key, ChanSigner, T, F, L, C>
- where T::Target: BroadcasterInterface,
+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,
- C::Target: ChainWatchInterface,
{
fn get_and_clear_pending_events(&self) -> Vec<Event> {
let mut pending_events = Vec::new();
// Set once we've signed a holder commitment transaction and handed it over to our
// OnchainTxHandler. After this is set, no future updates to our holder commitment transactions
// may occur, and we fail any such monitor updates.
+ //
+ // In case of update rejection due to a locally already signed commitment transaction, we
+ // nevertheless store update content to track in case of concurrent broadcast by another
+ // remote monitor out-of-order with regards to the block view.
holder_tx_signed: bool,
// We simply modify last_block_hash in Channel's block_connected so that serialization is
secp_ctx: Secp256k1<secp256k1::All>, //TODO: dedup this a bit...
}
-/// Simple trait indicating ability to track a set of ChannelMonitors and multiplex events between
-/// them. Generally should be implemented by keeping a local SimpleManyChannelMonitor and passing
-/// events to it, while also taking any add/update_monitor events and passing them to some remote
-/// server(s).
-///
-/// In general, you must always have at least one local copy in memory, which must never fail to
-/// update (as it is responsible for broadcasting the latest state in case the channel is closed),
-/// and then persist it to various on-disk locations. If, for some reason, the in-memory copy fails
-/// to update (eg out-of-memory or some other condition), you must immediately shut down without
-/// taking any further action such as writing the current state to disk. This should likely be
-/// accomplished via panic!() or abort().
-///
-/// Note that any updates to a channel's monitor *must* be applied to each instance of the
-/// channel's monitor everywhere (including remote watchtowers) *before* this function returns. If
-/// an update occurs and a remote watchtower is left with old state, it may broadcast transactions
-/// which we have revoked, allowing our counterparty to claim all funds in the channel!
-///
-/// User needs to notify implementors of ManyChannelMonitor when a new block is connected or
-/// disconnected using their `block_connected` and `block_disconnected` methods. However, rather
-/// than calling these methods directly, the user should register implementors as listeners to the
-/// BlockNotifier and call the BlockNotifier's `block_(dis)connected` methods, which will notify
-/// all registered listeners in one go.
-pub trait ManyChannelMonitor: Send + Sync {
- /// The concrete type which signs for transactions and provides access to our channel public
- /// keys.
- type Keys: ChannelKeys;
-
- /// Adds a monitor for the given `funding_txo`.
- ///
- /// Implementer must also ensure that the funding_txo txid *and* outpoint are registered with
- /// any relevant ChainWatchInterfaces such that the provided monitor receives block_connected
- /// callbacks with the funding transaction, or any spends of it.
- ///
- /// Further, the implementer must also ensure that each output returned in
- /// monitor.get_outputs_to_watch() is registered to ensure that the provided monitor learns about
- /// any spends of any of the outputs.
- ///
- /// Any spends of outputs which should have been registered which aren't passed to
- /// ChannelMonitors via block_connected may result in FUNDS LOSS.
- fn add_monitor(&self, funding_txo: OutPoint, monitor: ChannelMonitor<Self::Keys>) -> Result<(), ChannelMonitorUpdateErr>;
-
- /// Updates a monitor for the given `funding_txo`.
- ///
- /// Implementer must also ensure that the funding_txo txid *and* outpoint are registered with
- /// any relevant ChainWatchInterfaces such that the provided monitor receives block_connected
- /// callbacks with the funding transaction, or any spends of it.
- ///
- /// Further, the implementer must also ensure that each output returned in
- /// monitor.get_watch_outputs() is registered to ensure that the provided monitor learns about
- /// any spends of any of the outputs.
- ///
- /// Any spends of outputs which should have been registered which aren't passed to
- /// ChannelMonitors via block_connected may result in FUNDS LOSS.
- fn update_monitor(&self, funding_txo: OutPoint, monitor: ChannelMonitorUpdate) -> Result<(), ChannelMonitorUpdateErr>;
-
- /// Used by ChannelManager to get list of HTLC resolved onchain and which needed to be updated
- /// with success or failure.
- ///
- /// You should probably just call through to
- /// ChannelMonitor::get_and_clear_pending_monitor_events() for each ChannelMonitor and return
- /// the full list.
- fn get_and_clear_pending_monitor_events(&self) -> Vec<MonitorEvent>;
-}
-
#[cfg(any(test, feature = "fuzztarget"))]
/// Used only in testing and fuzztarget to check serialization roundtrips don't change the
/// underlying object
feerate_per_kw: initial_holder_commitment_tx.feerate_per_kw,
htlc_outputs: Vec::new(), // There are never any HTLCs in the initial commitment transactions
};
- // Returning a monitor error before updating tracking points means in case of using
- // a concurrent watchtower implementation for same channel, if this one doesn't
- // reject update as we do, you MAY have the latest holder valid commitment tx onchain
- // for which you want to spend outputs. We're NOT robust again this scenario right
- // now but we should consider it later.
- onchain_tx_handler.provide_latest_holder_tx(initial_holder_commitment_tx).unwrap();
+ onchain_tx_handler.provide_latest_holder_tx(initial_holder_commitment_tx);
ChannelMonitor {
latest_update_id: 0,
/// up-to-date as our holder commitment transaction is updated.
/// Panics if set_on_holder_tx_csv has never been called.
pub(super) fn provide_latest_holder_commitment_tx_info(&mut self, commitment_tx: HolderCommitmentTransaction, htlc_outputs: Vec<(HTLCOutputInCommitment, Option<Signature>, Option<HTLCSource>)>) -> Result<(), MonitorUpdateError> {
- if self.holder_tx_signed {
- return Err(MonitorUpdateError("A holder commitment tx has already been signed, no new holder commitment txn can be sent to our counterparty"));
- }
let txid = commitment_tx.txid();
let sequence = commitment_tx.unsigned_tx.input[0].sequence as u64;
let locktime = commitment_tx.unsigned_tx.lock_time as u64;
feerate_per_kw: commitment_tx.feerate_per_kw,
htlc_outputs: htlc_outputs,
};
- // Returning a monitor error before updating tracking points means in case of using
- // a concurrent watchtower implementation for same channel, if this one doesn't
- // reject update as we do, you MAY have the latest holder valid commitment tx onchain
- // for which you want to spend outputs. We're NOT robust again this scenario right
- // now but we should consider it later.
- if let Err(_) = self.onchain_tx_handler.provide_latest_holder_tx(commitment_tx) {
- return Err(MonitorUpdateError("Holder commitment signed has already been signed, no further update of LOCAL commitment transaction is allowed"));
- }
+ self.onchain_tx_handler.provide_latest_holder_tx(commitment_tx);
self.current_holder_commitment_number = 0xffff_ffff_ffff - ((((sequence & 0xffffff) << 3*8) | (locktime as u64 & 0xffffff)) ^ self.commitment_transaction_number_obscure_factor);
mem::swap(&mut new_holder_commitment_tx, &mut self.current_holder_commitment_tx);
self.prev_holder_signed_commitment_tx = Some(new_holder_commitment_tx);
+ if self.holder_tx_signed {
+ return Err(MonitorUpdateError("Latest holder commitment signed has already been signed, update is rejected"));
+ }
Ok(())
}
}
/// Get the list of HTLCs who's status has been updated on chain. This should be called by
- /// ChannelManager via ManyChannelMonitor::get_and_clear_pending_monitor_events().
+ /// ChannelManager via [`chain::Watch::release_pending_monitor_events`].
+ ///
+ /// [`chain::Watch::release_pending_monitor_events`]: ../../chain/trait.Watch.html#tymethod.release_pending_monitor_events
pub fn get_and_clear_pending_monitor_events(&mut self) -> Vec<MonitorEvent> {
let mut ret = Vec::new();
mem::swap(&mut ret, &mut self.pending_monitor_events);
/// Gets the list of pending events which were generated by previous actions, clearing the list
/// in the process.
///
- /// This is called by ManyChannelMonitor::get_and_clear_pending_events() and is equivalent to
+ /// This is called by ChainMonitor::get_and_clear_pending_events() and is equivalent to
/// EventsProvider::get_and_clear_pending_events() except that it requires &mut self as we do
/// no internal locking in ChannelMonitors.
pub fn get_and_clear_pending_events(&mut self) -> Vec<Event> {
Vec::new()
}
- /// Called by SimpleManyChannelMonitor::block_connected, which implements
- /// ChainListener::block_connected.
- /// Eventually this should be pub and, roughly, implement ChainListener, however this requires
- /// &mut self, as well as returns new spendable outputs and outpoints to watch for spending of
- /// on-chain.
- fn block_connected<B: Deref, F: Deref, L: Deref>(&mut self, txn_matched: &[&Transaction], height: u32, block_hash: &BlockHash, broadcaster: B, fee_estimator: F, logger: L)-> Vec<(Txid, Vec<TxOut>)>
+ /// Processes transactions in a newly connected block, which may result in any of the following:
+ /// - update the monitor's state against resolved HTLCs
+ /// - punish the counterparty in the case of seeing a revoked commitment transaction
+ /// - force close the channel and claim/timeout incoming/outgoing HTLCs if near expiration
+ /// - detect settled outputs for later spending
+ /// - schedule and bump any in-flight claims
+ ///
+ /// Returns any transaction outputs from `txn_matched` that spends of should be watched for.
+ /// After called these are also available via [`get_outputs_to_watch`].
+ ///
+ /// [`get_outputs_to_watch`]: #method.get_outputs_to_watch
+ pub fn block_connected<B: Deref, F: Deref, L: Deref>(&mut self, header: &BlockHeader, txn_matched: &[(usize, &Transaction)], height: u32, broadcaster: B, fee_estimator: F, logger: L)-> Vec<(Txid, Vec<TxOut>)>
where B::Target: BroadcasterInterface,
F::Target: FeeEstimator,
L::Target: Logger,
{
- for tx in txn_matched {
+ for &(_, tx) in txn_matched {
let mut output_val = 0;
for out in tx.output.iter() {
if out.value > 21_000_000_0000_0000 { panic!("Value-overflowing transaction provided to block connected"); }
}
}
+ let block_hash = header.block_hash();
log_trace!(logger, "Block {} at height {} connected with {} txn matched", block_hash, height, txn_matched.len());
+
let mut watch_outputs = Vec::new();
let mut claimable_outpoints = Vec::new();
- for tx in txn_matched {
+ for &(_, tx) in txn_matched {
if tx.input.len() == 1 {
// Assuming our keys were not leaked (in which case we're screwed no matter what),
// commitment transactions and HTLC transactions will all only ever have one input,
self.onchain_tx_handler.block_connected(txn_matched, claimable_outpoints, height, &*broadcaster, &*fee_estimator, &*logger);
- self.last_block_hash = block_hash.clone();
+ self.last_block_hash = block_hash;
for &(ref txid, ref output_scripts) in watch_outputs.iter() {
self.outputs_to_watch.insert(txid.clone(), output_scripts.iter().map(|o| o.script_pubkey.clone()).collect());
}
watch_outputs
}
- fn block_disconnected<B: Deref, F: Deref, L: Deref>(&mut self, height: u32, block_hash: &BlockHash, broadcaster: B, fee_estimator: F, logger: L)
+ /// Determines if the disconnected block contained any transactions of interest and updates
+ /// appropriately.
+ pub fn block_disconnected<B: Deref, F: Deref, L: Deref>(&mut self, header: &BlockHeader, height: u32, broadcaster: B, fee_estimator: F, logger: L)
where B::Target: BroadcasterInterface,
F::Target: FeeEstimator,
L::Target: Logger,
{
+ let block_hash = header.block_hash();
log_trace!(logger, "Block {} at height {} disconnected", block_hash, height);
+
if let Some(_) = self.onchain_events_waiting_threshold_conf.remove(&(height + ANTI_REORG_DELAY - 1)) {
//We may discard:
//- htlc update there as failure-trigger tx (revoked commitment tx, non-revoked commitment tx, HTLC-timeout tx) has been disconnected
self.onchain_tx_handler.block_disconnected(height, broadcaster, fee_estimator, logger);
- self.last_block_hash = block_hash.clone();
+ self.last_block_hash = block_hash;
}
fn would_broadcast_at_height<L: Deref>(&self, height: u32, logger: &L) -> bool where L::Target: Logger {
projects / rust-lightning / blobdiff