Remove outdated line from get_route docs

[rust-lightning] / lightning / src / chain / channelmonitor.rs

diff --git a/lightning/src/chain/channelmonitor.rs b/lightning/src/chain/channelmonitor.rs
index 4c7da902be94455589b354f39358775d7d8cd31f..7fad40d9c2ed70f4252115b3d2f98d16ee2ac2b7 100644 (file)
--- a/lightning/src/chain/channelmonitor.rs
+++ b/lightning/src/chain/channelmonitor.rs
@@ -131,10 +131,39 @@ pub enum MonitorEvent {
 
        /// A monitor event that the Channel's commitment transaction was confirmed.
        CommitmentTxConfirmed(OutPoint),
+
+       /// Indicates a [`ChannelMonitor`] update has completed. See
+       /// [`ChannelMonitorUpdateErr::TemporaryFailure`] for more information on how this is used.
+       ///
+       /// [`ChannelMonitorUpdateErr::TemporaryFailure`]: super::ChannelMonitorUpdateErr::TemporaryFailure
+       UpdateCompleted {
+               /// The funding outpoint of the [`ChannelMonitor`] that was updated
+               funding_txo: OutPoint,
+               /// The Update ID from [`ChannelMonitorUpdate::update_id`] which was applied or
+               /// [`ChannelMonitor::get_latest_update_id`].
+               ///
+               /// Note that this should only be set to a given update's ID if all previous updates for the
+               /// same [`ChannelMonitor`] have been applied and persisted.
+               monitor_update_id: u64,
+       },
+
+       /// Indicates a [`ChannelMonitor`] update has failed. See
+       /// [`ChannelMonitorUpdateErr::PermanentFailure`] for more information on how this is used.
+       ///
+       /// [`ChannelMonitorUpdateErr::PermanentFailure`]: super::ChannelMonitorUpdateErr::PermanentFailure
+       UpdateFailed(OutPoint),
 }
-impl_writeable_tlv_based_enum_upgradable!(MonitorEvent, ;
+impl_writeable_tlv_based_enum_upgradable!(MonitorEvent,
+       // Note that UpdateCompleted and UpdateFailed are currently never serialized to disk as they are
+       // generated only in ChainMonitor
+       (0, UpdateCompleted) => {
+               (0, funding_txo, required),
+               (2, monitor_update_id, required),
+       },
+;
        (2, HTLCEvent),
        (4, CommitmentTxConfirmed),
+       (6, UpdateFailed),
 );
 
 /// Simple structure sent back by `chain::Watch` when an HTLC from a forward channel is detected on
@@ -628,7 +657,17 @@ pub(crate) struct ChannelMonitorImpl<Signer: Sign> {
 
        payment_preimages: HashMap<PaymentHash, PaymentPreimage>,
 
+       // Note that `MonitorEvent`s MUST NOT be generated during update processing, only generated
+       // during chain data processing. This prevents a race in `ChainMonitor::update_channel` (and
+       // presumably user implementations thereof as well) where we update the in-memory channel
+       // object, then before the persistence finishes (as it's all under a read-lock), we return
+       // pending events to the user or to the relevant `ChannelManager`. Then, on reload, we'll have
+       // the pre-event state here, but have processed the event in the `ChannelManager`.
+       // Note that because the `event_lock` in `ChainMonitor` is only taken in
+       // block/transaction-connected events and *not* during block/transaction-disconnected events,
+       // we further MUST NOT generate events during block/transaction-disconnection.
        pending_monitor_events: Vec<MonitorEvent>,
+
        pending_events: Vec<Event>,
 
        // Used to track on-chain events (i.e., transactions part of channels confirmed on chain) on
@@ -854,14 +893,19 @@ impl<Signer: Sign> Writeable for ChannelMonitorImpl<Signer> {
                        writer.write_all(&payment_preimage.0[..])?;
                }
 
-               writer.write_all(&byte_utils::be64_to_array(self.pending_monitor_events.len() as u64))?;
+               writer.write_all(&(self.pending_monitor_events.iter().filter(|ev| match ev {
+                       MonitorEvent::HTLCEvent(_) => true,
+                       MonitorEvent::CommitmentTxConfirmed(_) => true,
+                       _ => false,
+               }).count() as u64).to_be_bytes())?;
                for event in self.pending_monitor_events.iter() {
                        match event {
                                MonitorEvent::HTLCEvent(upd) => {
                                        0u8.write(writer)?;
                                        upd.write(writer)?;
                                },
-                               MonitorEvent::CommitmentTxConfirmed(_) => 1u8.write(writer)?
+                               MonitorEvent::CommitmentTxConfirmed(_) => 1u8.write(writer)?,
+                               _ => {}, // Covered in the TLV writes below
                        }
                }