<?php

 /// start ping.inc.php ///

 $g_icmp_error = "No Error";

 // timeout in ms

 function ping($host, $timeout)

 {

     $port = 0;

     $datasize = 64;

     global $g_icmp_error;

     $g_icmp_error = "No Error";

     $ident = array(ord('J'), ord('C'));

     $seq = array(rand(0, 255), rand(0, 255));

     $packet = '';

     $packet .= chr(8); // type = 8 : request

     $packet .= chr(0); // code = 0

     $packet .= chr(0); // checksum init

     $packet .= chr(0); // checksum init

     $packet .= chr($ident[0]); // identifier

     $packet .= chr($ident[1]); // identifier

     $packet .= chr($seq[0]); // seq

     $packet .= chr($seq[1]); // seq

     for ($i = 0; $i < $datasize; $i++)

         $packet .= chr(0);

     $chk = icmpChecksum($packet);

     $packet[2] = $chk[0]; // checksum init

     $packet[3] = $chk[1]; // checksum init

     $sock = socket_create(AF_INET, SOCK_RAW, getprotobyname('icmp'));

     $time_start = microtime(true);

     socket_sendto($sock, $packet, strlen($packet), 0, $host, $port);

     $read = array($sock);

     $write = NULL;

     $except = NULL;

     $select = socket_select($read, $write, $except, 0, $timeout * 1000);

     if ($select === NULL) {

         $g_icmp_error = "Select Error";

         socket_close($sock);

         return -1;

     } elseif ($select === 0) {

         $g_icmp_error = "Timeout";

         socket_close($sock);

         return -1;

     }

     $recv = '';

     $time_stop = microtime(true);

     socket_recvfrom($sock, $recv, 65535, 0, $host, $port);

     $recv = unpack('C*', $recv);

     if ($recv[10] !== 1) // ICMP proto = 1

     {

         $g_icmp_error = "Not ICMP packet";

         socket_close($sock);

         return -1;

     }

     if ($recv[21] !== 0) // ICMP response = 0

     {

         $g_icmp_error = "Not ICMP response";

         socket_close($sock);

         return -1;

     }

     if ($ident[0] !== $recv[25] || $ident[1] !== $recv[26]) {

         $g_icmp_error = "Bad identification number";

         socket_close($sock);

         return -1;

     }

     if ($seq[0] !== $recv[27] || $seq[1] !== $recv[28]) {

         $g_icmp_error = "Bad sequence number";

         socket_close($sock);

         return -1;

     }

     $ms = bcmul(bcsub($time_stop, $time_start, 6), 1000);

     if ($ms < 0) {

         $g_icmp_error = "Response too long";

         $ms = -1;

     }

     socket_close($sock);

     return $ms;

 }

 function icmpChecksum($data)

 {

     $bit = unpack('n*', $data);

     $sum = array_sum($bit);

     if (strlen($data) % 2) {

         $temp = unpack('C*', $data[strlen($data) - 1]);

         $sum += $temp[1];

     }

     $sum = ($sum >> 16) + ($sum & 0xffff);

     $sum += ($sum >> 16);

     return pack('n*', ~$sum);

 }

 function getLastIcmpError()

 {

     global $g_icmp_error;

     return $g_icmp_error;

 }

 /// end ping.inc.php ///

$ping = ping('www.baidu.com',200);

if ($ping > 0) {

    // ok

} else {

    // failed

}