请问php怎么使用自己构造的IP包头

<?php
//数据
$dns_id = "\x80\xc1";
$dns_flags = "\x01\x00";
$dns_count_queries = "\x00\x01";
$dns_count_answers = "\x00\x00";
$dns_count_auth_rr = "\x00\x00";
$dns_count_add_rr = "\x00\x00";
$dns_qry_name = "\x02\x69\x70\x02\x63\x6e\x00";
$dns_qry_type = "\x00\x01";
$dns_qry_class = "\x00\x01";
$dns = $dns_id . $dns_flags . $dns_count_queries . $dns_count_answers . $dns_count_auth_rr . $dns_count_add_rr . $dns_qry_name . $dns_qry_type . $dns_qry_class;

//IP头
$ip_version = "\x45"; //4位版本
$ip_hdr_len = ""; // 4位首部长度
$ip_dsfield = "\x00"; //8位服务类型
$ip_len = pack('n*',28 + strlen($dns)); //16位总长度
$ip_id = "\x55\xf0"; //16位标识
$ip_flags = "\x00"; //3位标识
$ip_frag_offset = "\x00"; // 13位偏移
$ip_ttl = "\x80"; //8位生存时间
$ip_proto = "\x11"; //8位协议
$ip_src = ipto16("192.168.1.100"); //32位源IP
$ip_dst = ipto16("8.8.4.4"); //32位目的IP
$ip_checksum = ipchecksum($ip_version,$ip_hdr_len,$ip_dsfield,$ip_len,$ip_id,$ip_flags,$ip_frag_offset,$ip_ttl,$ip_proto,$ip_src,$ip_dst); //16位首部效验和
$ip_header = $ip_version . $ip_hdr_len . $ip_dsfield . $ip_len . $ip_id . $ip_flags . $ip_frag_offset . $ip_ttl . $ip_proto . $ip_checksum . $ip_src . $ip_dst;


//UDP头
$udp_srcport = "\xfc\x39"; //16位源端口
$udp_dstport = "\x00\x35"; //16位目的端口
$udp_length = pack('n*',8 + strlen($dns)); //16位UDP长度
$udp_checksum = udpchecksum($ip_src,$ip_dst,$ip_proto,$udp_length,$udp_srcport,$udp_dstport,$dns); //16位UDP效验和
$udp = $udp_srcport . $udp_dstport . $udp_length . $udp_checksum;


//$buf = $ip_header . $udp . $dns;
$buf = $udp . $dns;

function send($host,$port,$buf,$dns_flags)
{
//    $socket = socket_create(AF_INET, SOCK_PACKET, getprotobyname("ip"));
    $socket = socket_create(AF_INET, SOCK_RAM,1);
    $timeout = array('sec'=>1,'usec'=>500000);
//    socket_set_option($socket,IPPROTO_IP,IP_HDRINCL,SO_RCVTIMEO,$timeout);
    socket_set_option($socket,SOL_SOCKET,SO_RCVTIMEO,$timeout);
//    while(1)
        socket_sendto($socket, $buf, strlen($buf), 0, $host, $port);
}

function udpchecksum($ip_src,$ip_dst,$ip_proto,$udp_length,$udp_srcport,$udp_dstport,$dns)
{
    $data = $ip_src . $ip_dst . "\x00" . $ip_proto . $udp_length . $udp_srcport . $udp_dstport . $udp_length . "\x00\x00" . $dns;
    if (strlen($data)%2)
    $data .= "\x00";
    $bit = unpack('n*', $data);
    $sum = array_sum($bit);
    while ($sum >> 16)
        $sum = ($sum >> 16) + ($sum & 0xffff);
    return pack('n*', ~$sum);
}

function ipchecksum($ip_version,$ip_hdr_len,$ip_dsfield,$ip_len,$ip_id,$ip_flags,$ip_frag_offset,$ip_ttl,$ip_proto,$ip_src,$ip_dst)
{
    $data = $ip_version . $ip_hdr_len . $ip_dsfield . $ip_len . $ip_id . $ip_flags . $ip_frag_offset . $ip_ttl . $ip_proto . "\x00\x00" . $ip_src . $ip_dst;
    $bit = unpack('n*', $data);
    $sum = array_sum($bit);
    while ($sum >> 16)
        $sum = ($sum >> 16) + ($sum & 0xffff);
    return pack('n*', ~$sum);
}

function ipto16($ip)
{
    $tmp = explode(".",$ip);
    $ip = "";
    foreach($tmp as $a => $b)
    {
        $tmp = dechex($b);
        if (strlen($tmp)==1)
            $tmp = "0" . $tmp;
        $ip .= $tmp;
    }
    $ip = pack("h*",$ip);
    return $ip;
}

send("8.8.4.4",53,$buf,$dns_flags);