Feerate changes are asymmetric, as they can only be sent by the funder.
For FUNDER, the remote feerate is set when upon send of
commitment_signed, and the local feerate is set on receipt of
revoke_and_ack.
For non-funder, the local feerate is set on receipt of
commitment_signed, and the remote feerate set on send of
revoke_and_ack. In our code, these two happen together.
channeld gets this right, but lightningd ignored the funder/fundee
distinction, and as a result, receipt of a commitment_signed by the
funder altered fees in the database. If there was a reconnection
event or restart, then these (incorrect) values would be used, causing
us to complain about a 'Bad commit_sig signature' and close the
channel.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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