We already know what the channel id is, we should go ahead and pass it
on to any listening plugins -- this makes clean up easier/possible
if a open fails early on and we've got reserved utxos.
Prior to this, all reconnect logic lived in channeld. If you
disconnected before we finished building a funding transaction, that was
no big deal. Now, however, we're waiting for the funding to lock in in
dualopend, instead of handing straight to channeld to wait.
So we need a way to restart dualopend.
This will make it possible to do RBF, since we can re-start the opening
process in dualopend while waiting for lock-in.
Note the new channel states are being used, DUALOPEND_INIT and
DUALOPEND_AWAITING_LOCKIN, to differentiate from openingd/channeld opens
We let the plugin decide what feerate to accept/whether or not to add
funds to the open. To aid this decision, we also send the plugin what we
(c-lightning) currently have as our max and min acceptable feerates.
We also now use these as our default for max/min acceptable feerate
range when sending an openchannel offer to a peer.
In the future, it might be a good idea to make these more easily
changeable, either via a config setting (?) or a command param.
This is handy/necessary for getting multifundchannel to work, as we need
to know what output to tell all the other peers about.
Changelog-Added: Experimental!! JSON-RPC: openchannel_init returns a field `funding_serial` that indicates the serial_id of the funding output in the provided PSBT
Rusty pointed out that having an empty channel_id is suboptimal; adding
another call is probably the right idea rather than re-using an existing
one.
Suggested-By: @rustyrussell
There are 3 commands for opening a channel with dualfunding.
`openchannel_init` is the first of these.
It initializes the open-channel dialog, and stops once we've run out of
updates (input/outputs) to send to the peer.
niftynei