a simple dns client send a quary message and explain response

/* 已测试平台：centos6.7 64位环境 */

函数：dns_health_check(char *server_ip, char *domain, char *type, char *proto, char *port)

参数： server_ip : 要检查的服务器ip地址 domain : 要查询的域名 type : 要查询的域名类型 A NS NAME MX SOA AAAA TXT proto ： 通过什么方式查询 TCP或者UDP port : dns服务器端口

返回值：DNS_SERVER_HEALTH 1 服务器健康 DNS_SERVER_NOT_HEALTH 2 服务器不健康

    PARAMETER_ERROR -1			参数有误
    QUARY_SEND_ERROR -3			发送查询包错误
    RESPONSE_RECV_ERROR -5		接受响应超时
    TCP_CONNECT_ERROR -4		TCP CONNECT失败
    SOCKET_ERROR -6				创建套接字失败

注意：参数全部以字符串形式传入 eg:result = dns_health_check("127.0.0.1", "www.baidu.com", "A", "UDP", "53"); result = dns_health_check("114.114.114.114", "163.com", "MX", "TCP", "53");