mbx_set_common_iface_multicast
struct mbx_set_common_iface_multicast *fwcmd;
fwcmd = (struct mbx_set_common_iface_multicast *)&mbx.payload;
sizeof (struct mbx_set_common_iface_multicast));
mbx.payload_length = sizeof (struct mbx_set_common_iface_multicast);