php版端口扫描器

php写的一个端口扫描器,有兴趣的同学可以研究一下.

<?php
$host = 'www.google.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(); 
} 
?>