rbf_channel -- Hook for handling RBF channel funding requests

DESCRIPTION

The rbf_channel hook is called when a peer proposes replacing the funding transaction of an existing channel using Replace-By-Fee (RBF).

The plugin can choose to reject or continue the negotiation.

If continuing, the plugin may contribute additional inputs and outputs by returning a PSBT and specifying an our_funding_msat amount.

The our_funding_msat value must not be included in any output in the PSBT. Change outputs should be included and calculated using the provided funding_feerate_per_kw.

HOOK PAYLOAD

• rbf_channel (object):
  • id (pubkey): The node_id of the peer proposing the RBF.
  • channel_id (hash): The channel_id of the channel being modified.
  • their_last_funding_msat (msat): The peer's previous contribution to the funding transaction.
  • their_funding_msat (msat): The peer's proposed new funding contribution.
  • our_last_funding_msat (msat): Our previous contribution to the funding transaction.
  • funding_feerate_per_kw (u32): The feerate to use for the updated funding transaction, in satoshis per kw.
  • feerate_our_max (u32): The maximum feerate we are willing to accept for the funding transaction.
  • feerate_our_min (u32): The minimum feerate we are willing to accept for the funding transaction.
  • channel_max_msat (msat): The maximum total channel capacity allowed for this channel.
  • locktime (u32): The locktime to use for the funding transaction.
  • require_confirmed_inputs (boolean): Indicates whether the remote peer requires all inputs in the PSBT to be confirmed.
    If true, the plugin must avoid adding unconfirmed inputs. (added v23.02)
  • requested_lease_msat (msat, optional): If present, the amount of liquidity the peer is requesting us to lease.
    This field is optional and only included if the peer requested a lease.

HOOK RETURN

• result (string) (one of "continue", "reject"): Whether to accept or reject the RBF proposal.
• psbt (string, optional): A PSBT containing additional inputs and outputs to contribute to the funding transaction.
  Only valid if result is continue.
• our_funding_msat (msat, optional): The amount we are contributing to the new funding transaction.
  Must not be included in any output in the PSBT.
• error_message (string, optional): An error message explaining the rejection.
  Only used if result is reject and will be sent to the peer.