rc_acked
if (rp->rc_acked != RC_NO_ACK)
rp->rc_acked = RC_NO_ACK;
} else if (rp->rc_acked != RC_NO_SEQ) {
if (rp->rc_acked == RC_NO_ACK)
rp->rc_acked = RC_ACK;
rp->rc_acked = RC_NACK;
rp->rc_acked == RC_ACK) {
rp->rc_acked == RC_ACK))