HttpSecureLink limit by IP

Any chance to protect file(link) by users IP address...

My nginx.conf
location ~ \.flv$ {

secure_link $arg_st,$arg_e;
secure_link_md5 segredo$uri$arg_e;
if ($secure_link = "") {
return 403;
}
if ($secure_link = "0") {
return 403;
}

root /media;
flv;
}


Im try to add secure_link $arg_st,$arg_e,$arg_ip;

and than send &ip=127.0.0.1
but not working in this way