add_end(add_msg_type(&m->options[4], DHCPDISCOVER));
add_end(add_req_options(add_msg_type(&m->options[4], DHCPDISCOVER)));
send_discover(void){  struct dhcp_msg *m = (struct dhcp_msg *)uip_appdata;  create_msg(m);  add_end(add_msg_type(&m->options[4], DHCPDISCOVER));    uip_udp_send(300);}