FIP_VN_FC_MAP
hton24(fip->dest_addr, FIP_VN_FC_MAP);
hton24(frame->eth.h_source, FIP_VN_FC_MAP);
hton24(frame->vn.fd_mac, FIP_VN_FC_MAP);
hton24(mac, FIP_VN_FC_MAP);
hton24(mac->fd_mac, FIP_VN_FC_MAP);