We delegate the decision about what to do about 'out of bound' feerates
to the plugin (if one exists), however in the case that the plugin
doesnt exist or doesnt want to figure it out, we default to using the
'best' as their intended feerate, and rejecting if it's out of bounds.
We need to know if they've sent us their sigs message yet. Ideally, we'd
be able to check the 'finalness' of the PSBT, however if the peer
doesn't have any inputs to the channel this doesn't work.
Back in the days before dual-funding, the `channel` struct on subd was
only every one type per daemon (either struct channel or struct
uncommitted_channel)
The RBF requirement on dualopend means that dualopend's channel,
however, can now be two different things -- either channel or
uncommitted_channel.
To track the difference/disambiguate, we now track the channel type on a
flag on the subd. It gets updated when we swap out the channel.
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
Since this all stays in dualopend/dual_open_control, we can hold
onto the openchannel_signed command to wait for a response here locally.
Previously we were splitting across the channeld/openingd boundary.
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.
Prior to this patch update, we expected a client to call
`openchannel_signed` before checking for peer's tx-sigs messages on the
wire.
When moving to a 'multifundchannel' approach, we'll need to be able to
collect sigs from our peers before sending our tx_sigs message. There's
no strict ordering on when tx-sigs messages are sent/received, so this
is fine.
To do this, we go ahead and start up channeld as soon as
commitment_sigs are secured, so that we process incoming tx-sigs from
our peers as soon as we get them.
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
`openchannel_signed` and `openchannel_update` which allow a user to
continue a openchannel or kick off the completion of a openchannel.
`openchannel_update` should be called until it returns with
`commitments_secured`.
We need the PSBT to create the finalized tx from once the peer's
tx_signatures are received. Since we're passing the PSBT, we no longer
need the secondary message to be passed, as it was derived from the
PSBT.
Also removes now unused witness serialization code
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.
We force use of tal_wally_start/tal_wally_end around every wally
allocation, and with "end" make the caller choose where to reparent
everything.
This is particularly powerful where we allocate a tx or a psbt: we
want that tx or psbt to be the parent of the other allocations, so
this way we can reparent the tx or psbt, then reparent everything
else onto it.
Implementing psbt_finalize (which uses a behavior flag antipattern)
was tricky, so I ended up splitting that into 'psbt_finalize' and
'psbt_final_tx', which I think also makes the callers clearer.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
wallet_commit_channel would fill in the old_remote_per_commit and
fee_states, which is weird since the caller doesn't care.
Make the caller set all the channel_info fields, so wallet_commit_channel
is a simple consumer.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
niftynei
Rusty Russell
Michael Schmoock
Antoine Poinsot