This commit restructures the initialization procedure
for chain watchers such that they can proceed in parallel.
This is primarily to help nodes running with the neutrino
backend, which otherwise forces a serial rescan for each
active channel to check for spentness.
Doing so allows the rescans to take advantage of batch
scheduling in registering for the spend notifications,
ensuring that only one or two passes are made, as opposed
to one for each channel.
Lastly, this commit ensures that the chain arb is properly
shutdown if any of it's chain watchers or channel arbs
fails to start, so as to cancel their goroutines before
exiting.
At ChannelArbitrator startup we now check the database close status of
the channel. If we detect that the channel is closed, but our state
machine hasn't advanced to reflect that (possibly because of a shutdown
before the state transition was finished), we manually trigger the state
transition to recover.
This commit moves the responsibility for closing local and remote force
closes in the database from the chain watcher to the channel arbitrator.
We do this because we previously would close the channel in the
database, before sending the event to the channel arbitrator. This could
lead to a situation where the channel was marked closed, but the channel
arbitrator didn't receive the event before shutdown. As we don't listen
for chain events for channels that are closed, those channels would be
stuck in the pending close state forever, as the channel arbitrator
state machine wouldn't progress.
We fix this by letting the ChannelArbitrator close the channel in the
database. After the contract resolutions are logged (in the state
callback before transitioning to StateContractClosed) we mark the
channel closed in the database. This way we make sure that it is marked
closed only if the resolutions have been successfully persisted.
This commit removes the state callback, and instead logs the contract
resolutions directly after receiving the unilateral close event. The
resolutions won't change so there's not really necessary to wait to log
them, and this greatly simplifies the code.
This commit attempts to fix an inconsistency in when we consider an HTLC
to expire. When we first launched the resolver we would compare the
current block height against the expiry, while for new incoming blocks
we would compare against expiry-1.
This lead to a flake during integration tests, during a call to
RestartNode after _exactly_ enough blocks for the HTLC to expire. In
some cases the resolver would see the new blocks and consider the HTLC
to be expired (because of the -1), while in some cases resolver would
shut down before seeing the new blocks, and upon restart wouldn't act on
the new height because we did not compare against -1.
This commit fixes this by doing the same comparison in both cases.
Due to a recent change within the codebase to return estimated fee rates
in sat/kw, this commit ensures that we use this fee rate properly by
calculing a transaction's fees using its weight. This includes all of
the different transactions that are created within lnd (funding, sweeps,
etc.). On-chain transactions still rely on a sat/vbyte fee rate since it's
required by btcwallet.
This commit fixes a potential race condition during
shutdown, that could allow the chain arb's
activeWatchers or activeChannels map to be modified
while ranging over their contents. We fix this by
copying the contents into new maps with the mutex
held, before releasing the mutex and shutting down
each watcher or channel arbitrator.
This commit makes the chainwatcher attempt to dispatch a remote close
when it detects a remote state with a state number higher than our
known remote state. This can mean that we lost some state, and we check
the database for (hopefully) a data loss commit point retrieved during
channel sync with the remote peer. If this commit point is found in the
database we use it to try to recover our funds from the commitment.
This commit fixes a potential race condition within the
IncomingContestResolver, that could cause us to miss a
preimage that was delivered in time.
Currently we query the db for the preimage, and then
subscribe for notifications. This permits the following
ordering of events:
- query for preimage, returns nothing
- preimage is added and delivered to subscribers
- subscribe to preimages
- preimage never comes through!!
We fix this by reordering to subscribe for preimages and
then query just in case it already exists. The effect is
that the query will always return a valid read of the
preimages that are currently queued for delivery.
