In the coming commits, in order to ensure all routes we generate
are usable, we'll start calculating the next-HTLC minimum for our
channels and using it in the router. Here we set this up by adding
an always-0 field for it in `ChannelDetails` and use it when
routing.
If the `networks` field is present in a received `Init` message, then
we need to make sure our genesis chain hash matches one of those, otherwise
we should disconnect the peer.
We now also always send our genesis chain hash in `Init` messages to
our peers.
This was a fairly old introduction to the spec to allow nodes to indicate
to their peers what chains they are interested in (i.e. will open channels
and gossip for).
We don't do any of the handling of this message in this commit and leave
that to the very next commit, so the behaviour is effectively the same
(ignore networks preference).
When we forward a payment and receive an `update_fulfill_htlc`
message from the downstream channel, we immediately claim the HTLC
on the upstream channel, before even doing a `commitment_signed`
dance on the downstream channel. This implies that our
`ChannelMonitorUpdate`s "go out" in the right order - first we
ensure we'll get our money by writing the preimage down, then we
write the update that resolves giving money on the downstream node.
This is safe as long as `ChannelMonitorUpdate`s complete in the
order in which they are generated, but of course looking forward we
want to support asynchronous updates, which may complete in any
order.
Here we add infrastructure to handle downstream
`ChannelMonitorUpdate`s which are blocked on an upstream
preimage-containing one. We don't yet actually do the blocking which
will come in a future commit.
If a `ChannelMonitorUpdate` was created and given to the user but
left uncompleted when the `ChannelManager` is persisted prior to a
restart, the user likely lost the `ChannelMonitorUpdate`(s). Thus,
we need to replay them for the user, which we do here using the
new `BackgroundEvent::MonitorUpdateRegeneratedOnStartup` variant.
When we generated a `ChannelMonitorUpdate` during `ChannelManager`
deserialization, we must ensure that it gets processed before any
other `ChannelMonitorUpdate`s. The obvious hook for this is when
taking the `total_consistency_lock`, which makes it unlikely we'll
regress by forgetting this.
Here we add that call in the `PersistenceNotifierGuard`, with a
test-only atomic bool to test that this criteria is met.
`BackgroundEvent` was used to store `ChannelMonitorUpdate`s which
result in a channel force-close, avoiding relying on
`ChannelMonitor`s having been loaded while `ChannelManager`
block-connection methods are called during startup.
In the coming commit(s) we'll also generate non-channel-closing
`ChannelMonitorUpdate`s during startup, which will need to be
replayed prior to any other `ChannelMonitorUpdate`s generated from
normal operation.
In the next commit we'll handle that by handling `BackgroundEvent`s
immediately after locking the `total_consistency_lock`.
Rather than letting `AChannelManager` be bounded by all traits
being `Sized` we make them explicitly `?Sized`. We also make the
trait no longer test-only as it will be used in a coming commit.
In the coming commits we'll need the counterparty node_id when
handling a background monitor update as we may need to resume
normal channel operation as a result. Thus, we go ahead and pipe it
through from the shutdown end, as it makes the codepaths
consistent.
Sadly, the monitor-originated shutdown case doesn't allow for a
required counterparty node_id as some versions of LDK didn't have
it present in the ChannelMonitor.
At times, we've noticed that channels with `lnd` counterparties do not
receive messages we expect to in a timely manner (or at all) after
sending them a `ChannelReestablish` upon reconnection, or a
`CommitmentSigned` message. This can block the channel state machine
from making progress, eventually leading to force closes, if any pending
HTLCs are committed and their expiration is met.
It seems common wisdom for `lnd` node operators to periodically restart
their node/reconnect to their peers, allowing them to start from a fresh
state such that the message we expect to receive hopefully gets sent. We
can achieve the same end result by disconnecting peers ourselves
(regardless of whether they're a `lnd` node), which we opt to implement
here by awaiting their response within two timer ticks.
Previously, we would panic when failing to construct onion messages in
certain circumstances. Here we opt to always rather error out and don't
panic if something goes wrong during OM packet construction.
Rather than using the std benchmark framework (which isn't
maintained and is unlikely to get any further maintenance), we swap
for criterion, which at least gets us a variable number of test
runs so our benchmarks don't take forever.
We also fix the RGS benchmark to pass now that the file in use is
stale compared to today's date.
This PR aims to create a "stateless" scorer. Instead of passing
in fee params at construction-time, we want to parametrize the
scorer with an associated "parameter" type, which is then
passed to the router function itself, and allows passing
different parameters per route-finding call.
`rust-bitcoin v0.30.0` introduces concrete variants for data members of
block `Header`s. To avoid having to update these across every use, we
introduce new helpers to create dummy blocks and headers, such that the
update process is a bit more straight-forward.
This makes much clearer at sites generating such events that they
will be lost on restart, to reduce risk of bugs creeping in due to
lost monitor updates.
In d4810087c1 we added logic to apply `ChannelMonitorUpdate`s which
were a part of a channel closure async via a background queue to
address some startup issues. When we did that we persisted those
updates to ensure we replayed them when starting next time.
However, there was no reason to - if we persisted and then
restarted even without those monitor updates we'd find a monitor
without a channel, which we'd tell to broadcast the latest
commitment transaction to force-close.
Since adding that logic, we've used the same background queue for
several purposes.
The previous commits set up the ability for us to hold
`ChannelMonitorUpdate`s which are pending until we're ready to pass
them to users and have them be applied. However, if the
`ChannelManager` is persisted while we're waiting to give the user
a `ChannelMonitorUpdate` we'll be confused on restart - seeing our
latest `ChannelMonitor` state as stale compared to our
`ChannelManager` - a critical error.
Luckily the solution is trivial, we simply need to store the
pending `ChannelMonitorUpdate` state and load it with the
`ChannelManager` data, allowing stale monitors on load as long as
we have the missing pending updates between where we are and the
latest `ChannelMonitor` state.
This adds handling of the new `EventCompletionAction`s after
`Event`s are handled, letting `ChannelMonitorUpdate`s which were
blocked fly after a relevant `Event`.
This will allow us to block `ChannelMonitorUpdate`s on `Event`
processing in the next commit.
Note that this gets dangerously close to breaking forwards
compatibility - if we have an `Event` with an
`EventCompletionAction` tied to it, we persist a new, even, TLV in
the `ChannelManager`. Hopefully this should be uncommon, as it
implies an `Event` was delayed until after a full round-trip to a
peer.
In the coming commits, we need to delay `ChannelMonitorUpdate`s
until future actions (specifically `Event` handling). However,
because we should only notify users once of a given
`ChannelMonitorUpdate` and they must be provided in-order, we need
to track which ones have or have not been given to users and, once
updating resumes, fly the ones that haven't already made it to
users.
To do this we simply add a `bool` in the `ChannelMonitorUpdate` set
stored in the `Channel` which indicates if an update flew and
decline to provide new updates back to the `ChannelManager` if any
updates have their flown bit unset.
Further, because we'll now by releasing `ChannelMonitorUpdate`s
which were already stored in the pending list, we now need to
support getting a `Completed` result for a monitor which isn't the
only pending monitor (or even out of order), thus we also rewrite
the way monitor updates are marked completed.
