This includes when building TxCreationKeys, as well as for open_channel
and accept_channel messages. Note: this is only for places where we are
retrieving the current per commitment point, which excludes
channel_reestablish.
For quite some time, LDK has force-closed channels if the peer
sends us a feerate update which is below our `FeeEstimator`'s
concept of a channel lower-bound. This is intended to ensure that
channel feerates are always sufficient to get our commitment
transaction confirmed on-chain if we do need to force-close.
However, we've never checked our channel feerate regularly - if a
peer is offline (or just uninterested in updating the channel
feerate) and the prevailing feerates on-chain go up, we'll simply
ignore it and allow our commitment transaction to sit around with a
feerate too low to get confirmed.
Here we rectify this oversight by force-closing channels with stale
feerates, checking after each block. However, because fee
estimators are often buggy and force-closures piss off users, we
only do so rather conservatively. Specifically, we only force-close
if a channel's feerate is below the minimum `FeeEstimator`-provided
minimum across the last day.
Further, because fee estimators are often especially buggy on
startup (and because peers haven't had a chance to update the
channel feerates yet), we don't force-close channels until we have
a full day of feerate lower-bound history.
This should reduce the incidence of force-closures substantially,
but it is expected this will still increase force-closures somewhat
substantially depending on the users' `FeeEstimator`.
Fixes#993
When we connect 100 blocks in a row, requiring the fuzz input to
contain 100 fee estimator results is uneccessary, so add a bool
that lets us skip those reads.
Closure due to feerate disagreements are a specific closure reason
which admins can understand and tune their config (in the form of
their `FeeEstimator`) to avoid, so having a separate
`ClosureReason` for it is useful.
In the next commit we'll add a second field to
`ChannelError::Close` so here we prep by converting existing calls
to the constructor function, which is almost a full-file sed.
.. the bindings branch needed a small patch as it doesn't support `dyn`
traits. Here, we opt to use `Deref` in the hopes this works with
bindings, rendering the patch unnecessary.
