PHP判断端口是否打开的代码

<?php
 $host = 'www.baidu.com'; //要ping的地址，也可以是IP
 $port = '80'; //要ping的端口
 $num  = 3;
function microtime_float()
{
        list($usec, $sec) = explode(" ", microtime());
        return ((float)$usec + (float)$sec);
}
function ping($host,$port)
{
        $time_start = microtime_float();
        $ip = gethostbyname($host);
        $fp = @fsockopen($host,$port,&$errno,&$errstr,1);
        if(!$fp) return 'replay time out!';
        $get = "GET / HTTP/1.1\r\nHost:".$host."\r\nConnection: Close\r\n\r\n";
        @fputs($fp,$get);
        @fclose($fp);
        $time_end = microtime_float();
        $time = $time_end - $time_start;
        $time = ceil($time * 1000);
        return 'Reply from '.$ip.': time='.$time.'ms<br />';
}
echo 'Pinging '.$host.' ['.gethostbyname($host).'] with Port:'.$port.' of data:<br /><br />'."\r\n";
for($i = 0;$i < $num;$i++)
{        
        ping($host,$port);
        sleep(1);
        ob_flush();
        flush();
}
?>

记下来，到时候找的时候不用麻烦了