There's a version of this that keeps the PSBT in memory and does some
fancy addition/subtraction of unuseable parts for the v2's, however
it's much easier and simpler to simply error on the peer and re-start
from the very beginning.
This only works if we haven't gotten commitments from the peer yet (in
fact either method would only work if we haven't got commitments from
the peer yet), so if we've got commitments from them we simply mark them
as failed an go again.
In a perfect world, we'd remember what inputs we used last time, and
reuse those again on the re-attempt, which would pefectly guarantee both
that the failed opens (ones w/ commitments exchanged) would be canceled
after this completes (and we could re-try the failed again).
As it is, this is not perfect. It is, however, servicable.
We consolidate to the latest/singular RFC patch for dual-funding, so
there's just a single patchfile for the change. Plus we move back to the
opener setting the desired feerate, the accepter merely declines to
participate if they disagree with the set rate.
We should actually be including this (as it may define _GNU_SOURCE
etc) before any system headers. But where we include <assert.h> we
often didn't, because check-includes would complain that the headers
included it too.
Weaken that check, and include config.h in C files before assert.h.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Since we round down in `amount_tx_fee`, find the change fee as the
difference between what we've already paid and what the combined/total
fee would be if the change weight were also added.
We'll use it for figuring out whether or not to set a utxo witness
minimum, which comes much before we were setting this field.
Now we set the protocol as soon as we can reasonably deduce it.
we only want to sign the inputs that we've reserved via utxopsbt or
fundpsbt. we mark them with a flag (reusing the now defunct max-len
flag is fine), then look for inputs with that flag to pass to signonly
We only have output scripts for v1 protocols after the
fundchannel_start/openchannel_init round. We need to add them before
we get into the openchannel_update rounds, however, so we do that here.
Technically there *are* two feerates that we need to know:
- the feerate to use for the funding transaction, and
- the feerate to tell our peer to use for our commitment txs/htlc txs
As written, `multifundchannel` uses the same feerate for both. This
optional parameter will allow us to differentiate between the two, which
will be exceedingly handy for anchor output worlds. ;)
FIXME: test this
Changelog-Added: JSON API: `multifundchannel` has a new optional argument, 'commitment_feerate', which can be used to differentiate between the funding feerate and the channel's initial commitment feerate
