//! servicing [`ChannelMonitor`] updates from the client.
use bitcoin::blockdata::block::BlockHeader;
-use bitcoin::hash_types::Txid;
+use bitcoin::hash_types::{Txid, BlockHash};
use crate::chain;
use crate::chain::{ChannelMonitorUpdateStatus, Filter, WatchedOutput};
use crate::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
use crate::chain::channelmonitor::{ChannelMonitor, ChannelMonitorUpdate, Balance, MonitorEvent, TransactionOutputs, LATENCY_GRACE_PERIOD_BLOCKS};
use crate::chain::transaction::{OutPoint, TransactionData};
-use crate::chain::keysinterface::Sign;
+use crate::sign::WriteableEcdsaChannelSigner;
+use crate::events;
+use crate::events::{Event, EventHandler};
use crate::util::atomic_counter::AtomicCounter;
use crate::util::logger::Logger;
use crate::util::errors::APIError;
-use crate::util::events;
-use crate::util::events::EventHandler;
+use crate::util::wakers::{Future, Notifier};
use crate::ln::channelmanager::ChannelDetails;
use crate::prelude::*;
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 {
+ pub(crate) fn from_new_monitor<ChannelSigner: WriteableEcdsaChannelSigner>(monitor: &ChannelMonitor<ChannelSigner>) -> Self {
Self { contents: UpdateOrigin::OffChain(monitor.get_latest_update_id()) }
}
}
/// [`ChannelMonitorUpdateStatus::PermanentFailure`], in which case the channel will likely be
/// closed without broadcasting the latest state. See
/// [`ChannelMonitorUpdateStatus::PermanentFailure`] for more details.
-pub trait Persist<ChannelSigner: Sign> {
+pub trait Persist<ChannelSigner: WriteableEcdsaChannelSigner> {
/// 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.
///
/// [`ChannelMonitorUpdateStatus`] 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) -> ChannelMonitorUpdateStatus;
+ fn update_persisted_channel(&self, channel_id: OutPoint, update: Option<&ChannelMonitorUpdate>, data: &ChannelMonitor<ChannelSigner>, update_id: MonitorUpdateId) -> ChannelMonitorUpdateStatus;
}
-struct MonitorHolder<ChannelSigner: Sign> {
+struct MonitorHolder<ChannelSigner: WriteableEcdsaChannelSigner> {
monitor: ChannelMonitor<ChannelSigner>,
/// The full set of pending monitor updates for this Channel.
///
last_chain_persist_height: AtomicUsize,
}
-impl<ChannelSigner: Sign> MonitorHolder<ChannelSigner> {
+impl<ChannelSigner: WriteableEcdsaChannelSigner> 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 })
///
/// Note that this holds a mutex in [`ChainMonitor`] and may block other events until it is
/// released.
-pub struct LockedChannelMonitor<'a, ChannelSigner: Sign> {
+pub struct LockedChannelMonitor<'a, ChannelSigner: WriteableEcdsaChannelSigner> {
lock: RwLockReadGuard<'a, HashMap<OutPoint, MonitorHolder<ChannelSigner>>>,
funding_txo: OutPoint,
}
-impl<ChannelSigner: Sign> Deref for LockedChannelMonitor<'_, ChannelSigner> {
+impl<ChannelSigner: WriteableEcdsaChannelSigner> Deref for LockedChannelMonitor<'_, ChannelSigner> {
type Target = ChannelMonitor<ChannelSigner>;
fn deref(&self) -> &ChannelMonitor<ChannelSigner> {
&self.lock.get(&self.funding_txo).expect("Checked at construction").monitor
/// or used independently to monitor channels remotely. See the [module-level documentation] for
/// details.
///
+/// Note that `ChainMonitor` should regularly trigger rebroadcasts/fee bumps of pending claims from
+/// a force-closed channel. This is crucial in preventing certain classes of pinning attacks,
+/// detecting substantial mempool feerate changes between blocks, and ensuring reliability if
+/// broadcasting fails. We recommend invoking this every 30 seconds, or lower if running in an
+/// environment with spotty connections, like on mobile.
+///
/// [`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>
+/// [`rebroadcast_pending_claims`]: Self::rebroadcast_pending_claims
+pub struct ChainMonitor<ChannelSigner: WriteableEcdsaChannelSigner, C: Deref, T: Deref, F: Deref, L: Deref, P: Deref>
where C::Target: chain::Filter,
T::Target: BroadcasterInterface,
F::Target: FeeEstimator,
pending_monitor_events: Mutex<Vec<(OutPoint, Vec<MonitorEvent>, Option<PublicKey>)>>,
/// The best block height seen, used as a proxy for the passage of time.
highest_chain_height: AtomicUsize,
+
+ event_notifier: Notifier,
}
-impl<ChannelSigner: Sign, C: Deref, T: Deref, F: Deref, L: Deref, P: Deref> ChainMonitor<ChannelSigner, C, T, F, L, P>
+impl<ChannelSigner: WriteableEcdsaChannelSigner, C: Deref, T: Deref, F: Deref, L: Deref, P: Deref> ChainMonitor<ChannelSigner, C, T, F, L, P>
where C::Target: chain::Filter,
T::Target: BroadcasterInterface,
F::Target: FeeEstimator,
}
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) {
+ match self.persister.update_persisted_channel(*funding_outpoint, None, monitor, update_id) {
ChannelMonitorUpdateStatus::Completed =>
log_trace!(self.logger, "Finished syncing Channel Monitor for channel {}", log_funding_info!(monitor)),
ChannelMonitorUpdateStatus::PermanentFailure => {
monitor_state.channel_perm_failed.store(true, Ordering::Release);
self.pending_monitor_events.lock().unwrap().push((*funding_outpoint, vec![MonitorEvent::UpdateFailed(*funding_outpoint)], monitor.get_counterparty_node_id()));
+ self.event_notifier.notify();
},
ChannelMonitorUpdateStatus::InProgress => {
log_debug!(self.logger, "Channel Monitor sync for channel {} in progress, holding events until completion!", log_funding_info!(monitor));
persister,
pending_monitor_events: Mutex::new(Vec::new()),
highest_chain_height: AtomicUsize::new(0),
+ event_notifier: Notifier::new(),
}
}
self.monitors.read().unwrap().keys().map(|outpoint| *outpoint).collect()
}
+ #[cfg(not(c_bindings))]
+ /// Lists the pending updates for each [`ChannelMonitor`] (by `OutPoint` being monitored).
+ pub fn list_pending_monitor_updates(&self) -> HashMap<OutPoint, Vec<MonitorUpdateId>> {
+ self.monitors.read().unwrap().iter().map(|(outpoint, holder)| {
+ (*outpoint, holder.pending_monitor_updates.lock().unwrap().clone())
+ }).collect()
+ }
+
+ #[cfg(c_bindings)]
+ /// Lists the pending updates for each [`ChannelMonitor`] (by `OutPoint` being monitored).
+ pub fn list_pending_monitor_updates(&self) -> Vec<(OutPoint, Vec<MonitorUpdateId>)> {
+ self.monitors.read().unwrap().iter().map(|(outpoint, holder)| {
+ (*outpoint, holder.pending_monitor_updates.lock().unwrap().clone())
+ }).collect()
+ }
+
+
#[cfg(test)]
pub fn remove_monitor(&self, funding_txo: &OutPoint) -> ChannelMonitor<ChannelSigner> {
self.monitors.write().unwrap().remove(funding_txo).unwrap().monitor
}
},
}
+ self.event_notifier.notify();
Ok(())
}
funding_txo,
monitor_update_id,
}], counterparty_node_id));
+ self.event_notifier.notify();
}
- #[cfg(any(test, fuzzing, feature = "_test_utils"))]
+ #[cfg(any(test, feature = "_test_utils"))]
pub fn get_and_clear_pending_events(&self) -> Vec<events::Event> {
- use crate::util::events::EventsProvider;
+ use crate::events::EventsProvider;
let events = core::cell::RefCell::new(Vec::new());
- let event_handler = |event: &events::Event| events.borrow_mut().push(event.clone());
+ let event_handler = |event: events::Event| events.borrow_mut().push(event);
self.process_pending_events(&event_handler);
events.into_inner()
}
+
+ /// Processes any events asynchronously in the order they were generated since the last call
+ /// using the given event handler.
+ ///
+ /// See the trait-level documentation of [`EventsProvider`] for requirements.
+ ///
+ /// [`EventsProvider`]: crate::events::EventsProvider
+ pub async fn process_pending_events_async<Future: core::future::Future, H: Fn(Event) -> Future>(
+ &self, handler: H
+ ) {
+ let mut pending_events = Vec::new();
+ 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 {
+ handler(event).await;
+ }
+ }
+
+ /// Gets a [`Future`] that completes when an event is available either via
+ /// [`chain::Watch::release_pending_monitor_events`] or
+ /// [`EventsProvider::process_pending_events`].
+ ///
+ /// Note that callbacks registered on the [`Future`] MUST NOT call back into this
+ /// [`ChainMonitor`] and should instead register actions to be taken later.
+ ///
+ /// [`EventsProvider::process_pending_events`]: crate::events::EventsProvider::process_pending_events
+ pub fn get_update_future(&self) -> Future {
+ self.event_notifier.get_future()
+ }
+
+ /// Triggers rebroadcasts/fee-bumps of pending claims from a force-closed channel. This is
+ /// crucial in preventing certain classes of pinning attacks, detecting substantial mempool
+ /// feerate changes between blocks, and ensuring reliability if broadcasting fails. We recommend
+ /// invoking this every 30 seconds, or lower if running in an environment with spotty
+ /// connections, like on mobile.
+ pub fn rebroadcast_pending_claims(&self) {
+ let monitors = self.monitors.read().unwrap();
+ for (_, monitor_holder) in &*monitors {
+ monitor_holder.monitor.rebroadcast_pending_claims(
+ &*self.broadcaster, &*self.fee_estimator, &*self.logger
+ )
+ }
+ }
}
-impl<ChannelSigner: Sign, C: Deref, T: Deref, F: Deref, L: Deref, P: Deref>
+impl<ChannelSigner: WriteableEcdsaChannelSigner, C: Deref, T: Deref, F: Deref, L: Deref, P: Deref>
chain::Listen for ChainMonitor<ChannelSigner, C, T, F, L, P>
where
C::Target: chain::Filter,
}
}
-impl<ChannelSigner: Sign, C: Deref, T: Deref, F: Deref, L: Deref, P: Deref>
+impl<ChannelSigner: WriteableEcdsaChannelSigner, 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,
});
}
- fn get_relevant_txids(&self) -> Vec<Txid> {
+ fn get_relevant_txids(&self) -> Vec<(Txid, Option<BlockHash>)> {
let mut txids = Vec::new();
let monitor_states = self.monitors.read().unwrap();
for monitor_state in monitor_states.values() {
}
}
-impl<ChannelSigner: Sign, C: Deref , T: Deref , F: Deref , L: Deref , P: Deref >
+impl<ChannelSigner: WriteableEcdsaChannelSigner, 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,
/// Note that we persist the given `ChannelMonitor` update while holding the
/// `ChainMonitor` monitors lock.
- fn update_channel(&self, funding_txo: OutPoint, update: ChannelMonitorUpdate) -> ChannelMonitorUpdateStatus {
+ fn update_channel(&self, funding_txo: OutPoint, update: &ChannelMonitorUpdate) -> ChannelMonitorUpdateStatus {
// Update the monitor that watches the channel referred to by the given outpoint.
let monitors = self.monitors.read().unwrap();
match monitors.get(&funding_txo) {
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);
+ let update_res = monitor.update_monitor(update, &self.broadcaster, &*self.fee_estimator, &self.logger);
if update_res.is_err() {
log_error!(self.logger, "Failed to update ChannelMonitor for channel {}.", log_funding_info!(monitor));
}
// 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 update_id = MonitorUpdateId::from_monitor_update(&update);
+ 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);
+ let persist_res = self.persister.update_persisted_channel(funding_txo, Some(update), monitor, update_id);
match persist_res {
ChannelMonitorUpdateStatus::InProgress => {
pending_monitor_updates.push(update_id);
}
}
-impl<ChannelSigner: Sign, C: Deref, T: Deref, F: Deref, L: Deref, P: Deref> events::EventsProvider for ChainMonitor<ChannelSigner, C, T, F, L, P>
+impl<ChannelSigner: WriteableEcdsaChannelSigner, C: Deref, T: Deref, F: Deref, L: Deref, P: Deref> events::EventsProvider for ChainMonitor<ChannelSigner, C, T, F, L, P>
where C::Target: chain::Filter,
T::Target: BroadcasterInterface,
F::Target: FeeEstimator,
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);
+ for event in pending_events {
+ handler.handle_event(event);
}
}
#[cfg(anchors)]
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);
+ for event in pending_events {
+ handler.handle_event(event);
}
}
}
#[cfg(test)]
mod tests {
- use bitcoin::{BlockHeader, TxMerkleNode};
- use bitcoin::hashes::Hash;
use crate::{check_added_monitors, check_closed_broadcast, check_closed_event};
use crate::{expect_payment_sent, expect_payment_claimed, expect_payment_sent_without_paths, expect_payment_path_successful, get_event_msg};
use crate::{get_htlc_update_msgs, get_local_commitment_txn, get_revoke_commit_msgs, get_route_and_payment_hash, unwrap_send_err};
use crate::chain::{ChannelMonitorUpdateStatus, Confirm, Watch};
use crate::chain::channelmonitor::LATENCY_GRACE_PERIOD_BLOCKS;
- use crate::ln::channelmanager::{self, PaymentSendFailure};
+ use crate::events::{Event, ClosureReason, MessageSendEvent, MessageSendEventsProvider};
+ use crate::ln::channelmanager::{PaymentSendFailure, PaymentId, RecipientOnionFields};
use crate::ln::functional_test_utils::*;
use crate::ln::msgs::ChannelMessageHandler;
use crate::util::errors::APIError;
- use crate::util::events::{ClosureReason, MessageSendEvent, MessageSendEventsProvider};
#[test]
fn test_async_ooo_offchain_updates() {
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);
- create_announced_chan_between_nodes(&nodes, 0, 1, channelmanager::provided_init_features(), channelmanager::provided_init_features());
+ create_announced_chan_between_nodes(&nodes, 0, 1);
// Route two payments to be claimed at the same time.
let (payment_preimage_1, payment_hash_1, _) = route_payment(&nodes[0], &[&nodes[1]], 1_000_000);
chanmon_cfgs[1].persister.offchain_monitor_updates.lock().unwrap().clear();
chanmon_cfgs[1].persister.set_update_ret(ChannelMonitorUpdateStatus::InProgress);
+ chanmon_cfgs[1].persister.set_update_ret(ChannelMonitorUpdateStatus::InProgress);
nodes[1].node.claim_funds(payment_preimage_1);
check_added_monitors!(nodes[1], 1);
- expect_payment_claimed!(nodes[1], payment_hash_1, 1_000_000);
nodes[1].node.claim_funds(payment_preimage_2);
check_added_monitors!(nodes[1], 1);
- expect_payment_claimed!(nodes[1], payment_hash_2, 1_000_000);
-
- chanmon_cfgs[1].persister.set_update_ret(ChannelMonitorUpdateStatus::Completed);
let persistences = chanmon_cfgs[1].persister.offchain_monitor_updates.lock().unwrap().clone();
assert_eq!(persistences.len(), 1);
// Note that updates is a HashMap so the ordering here is actually random. This shouldn't
// fail either way but if it fails intermittently it's depending on the ordering of updates.
let mut update_iter = updates.iter();
- nodes[1].chain_monitor.chain_monitor.channel_monitor_updated(*funding_txo, update_iter.next().unwrap().clone()).unwrap();
+ let next_update = update_iter.next().unwrap().clone();
+ // Should contain next_update when pending updates listed.
+ #[cfg(not(c_bindings))]
+ assert!(nodes[1].chain_monitor.chain_monitor.list_pending_monitor_updates().get(funding_txo)
+ .unwrap().contains(&next_update));
+ #[cfg(c_bindings)]
+ assert!(nodes[1].chain_monitor.chain_monitor.list_pending_monitor_updates().iter()
+ .find(|(txo, _)| txo == funding_txo).unwrap().1.contains(&next_update));
+ nodes[1].chain_monitor.chain_monitor.channel_monitor_updated(*funding_txo, next_update.clone()).unwrap();
+ // Should not contain the previously pending next_update when pending updates listed.
+ #[cfg(not(c_bindings))]
+ assert!(!nodes[1].chain_monitor.chain_monitor.list_pending_monitor_updates().get(funding_txo)
+ .unwrap().contains(&next_update));
+ #[cfg(c_bindings)]
+ assert!(!nodes[1].chain_monitor.chain_monitor.list_pending_monitor_updates().iter()
+ .find(|(txo, _)| txo == funding_txo).unwrap().1.contains(&next_update));
assert!(nodes[1].chain_monitor.release_pending_monitor_events().is_empty());
assert!(nodes[1].node.get_and_clear_pending_msg_events().is_empty());
+ assert!(nodes[1].node.get_and_clear_pending_events().is_empty());
nodes[1].chain_monitor.chain_monitor.channel_monitor_updated(*funding_txo, update_iter.next().unwrap().clone()).unwrap();
+ let claim_events = nodes[1].node.get_and_clear_pending_events();
+ assert_eq!(claim_events.len(), 2);
+ match claim_events[0] {
+ Event::PaymentClaimed { ref payment_hash, amount_msat: 1_000_000, .. } => {
+ assert_eq!(payment_hash_1, *payment_hash);
+ },
+ _ => panic!("Unexpected event"),
+ }
+ match claim_events[1] {
+ Event::PaymentClaimed { ref payment_hash, amount_msat: 1_000_000, .. } => {
+ assert_eq!(payment_hash_2, *payment_hash);
+ },
+ _ => panic!("Unexpected event"),
+ }
+
// Now manually walk the commitment signed dance - because we claimed two payments
// back-to-back it doesn't fit into the neat walk commitment_signed_dance does.
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, channelmanager::provided_init_features(), channelmanager::provided_init_features());
+ let channel = create_announced_chan_between_nodes(&nodes, 0, 1);
// Get a route for later and rebalance the channel somewhat
send_payment(&nodes[0], &[&nodes[1]], 10_000_000);
// Connect B's commitment transaction, but only to the ChainMonitor/ChannelMonitor. The
// channel is now closed, but the ChannelManager doesn't know that yet.
- let new_header = BlockHeader {
- version: 2, time: 0, bits: 0, nonce: 0,
- prev_blockhash: nodes[0].best_block_info().0,
- merkle_root: TxMerkleNode::all_zeros() };
+ let new_header = create_dummy_header(nodes[0].best_block_info().0, 0);
nodes[0].chain_monitor.chain_monitor.transactions_confirmed(&new_header,
&[(0, &remote_txn[0]), (1, &remote_txn[1])], nodes[0].best_block_info().1 + 1);
assert!(nodes[0].chain_monitor.release_pending_monitor_events().is_empty());
// If the ChannelManager tries to update the channel, however, the ChainMonitor will pass
// the update through to the ChannelMonitor which will refuse it (as the channel is closed).
chanmon_cfgs[0].persister.set_update_ret(ChannelMonitorUpdateStatus::Completed);
- unwrap_send_err!(nodes[0].node.send_payment(&route, second_payment_hash, &Some(second_payment_secret)),
- true, APIError::ChannelUnavailable { ref err },
+ unwrap_send_err!(nodes[0].node.send_payment_with_route(&route, second_payment_hash,
+ RecipientOnionFields::secret_only(second_payment_secret), PaymentId(second_payment_hash.0)
+ ), true, APIError::ChannelUnavailable { ref err },
assert!(err.contains("ChannelMonitor storage failure")));
check_added_monitors!(nodes[0], 2); // After the failure we generate a close-channel monitor update
check_closed_broadcast!(nodes[0], true);
if block_timeout {
// After three blocks, pending MontiorEvents should be released either way.
- let latest_header = BlockHeader {
- version: 2, time: 0, bits: 0, nonce: 0,
- prev_blockhash: nodes[0].best_block_info().0,
- merkle_root: TxMerkleNode::all_zeros() };
+ let latest_header = create_dummy_header(nodes[0].best_block_info().0, 0);
nodes[0].chain_monitor.chain_monitor.best_block_updated(&latest_header, nodes[0].best_block_info().1 + LATENCY_GRACE_PERIOD_BLOCKS);
} else {
let persistences = chanmon_cfgs[0].persister.chain_sync_monitor_persistences.lock().unwrap().clone();
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);
- create_announced_chan_between_nodes(&nodes, 0, 1, channelmanager::provided_init_features(), channelmanager::provided_init_features());
+ create_announced_chan_between_nodes(&nodes, 0, 1);
chanmon_cfgs[0].persister.chain_sync_monitor_persistences.lock().unwrap().clear();
chanmon_cfgs[0].persister.set_update_ret(ChannelMonitorUpdateStatus::PermanentFailure);
projects / rust-lightning / blobdiff