l2tp_cdn_rcode_string
"RecvCDN result=%s/%d", l2tp_cdn_rcode_string(result),
l2tp_cdn_rcode_string(result), result,
l2tp_cdn_rcode_string(result_code), result_code,
l2tp_cdn_rcode_string(result_code), result_code);
const char * l2tp_cdn_rcode_string(int);