PHP implementation code to prevent Ddos, DNS, and cluster attacks

/**
* Prevent ddos, dns, cluster and other attacks
* edit bbs.it-home.org
*/
//查询禁止IP
$ip =$_SERVER['REMOTE_ADDR'];
$fileht=".htaccess2";
if(!file_exists($fileht))
file_put_contents($fileht,"");
$filehtarr=@file($fileht);
if(in_array($ip."rn",$filehtarr))
die("Warning:".""."Your IP address are forbided by some reason, IF you have any question Pls emill to shop@jbxue.com!");
//加入禁止IP
$time=time();
$fileforbid="log/forbidchk.dat";
if(file_exists($fileforbid)) {
if($time-filemtime($fileforbid)>60)
unlink($fileforbid);
else {
$fileforbidarr=@file($fileforbid);
if($ip==substr($fileforbidarr[0],0,strlen($ip))) {
if($time-substr($fileforbidarr[1],0,strlen($time))>600)
unlink($fileforbid);
elseif($fileforbidarr[2]>600) {
file_put_contents($fileht,$ip."rn",FILE_APPEND);
unlink($fileforbid);
} else {
$fileforbidarr[2]++;
file_put_contents($fileforbid,$fileforbidarr);
}
}
}
}
//防刷新
$str="";
$file="log/ipdate.dat";
if(!file_exists("log")&&!is_dir("log"))
mkdir("log",0777);
if(!file_exists($file))
file_put_contents($file,"");
$allowTime = 120;//防刷新时间
$allowNum=10;//防刷新次数
$uri=$_SERVER['REQUEST_URI'];
$checkip=md5($ip);
$checkuri=md5($uri);
$yesno=true;
$ipdate=@file($file);
foreach($ipdate as $k=>$v) {
$iptem=substr($v,0,32);
$uritem=substr($v,32,32);
$timetem=substr($v,64,10);
$numtem=substr($v,74);
if($time-$timetem<$allowTime) {
if($iptem!=$checkip)
$str.=$v;
else {
$yesno=false;
if($uritem!=$checkuri)
$str.=$iptem.$checkuri.$time."1rn";
elseif($numtem<$allowNum)
$str.=$iptem.$uritem.$timetem.($numtem+1)."rn";
else {
if(!file_exists($fileforbid)) {
$addforbidarr=array($ip."rn",time()."rn",1);
file_put_contents($fileforbid,$addforbidarr);
}
file_put_contents("log/forbided_ip.log",$ip."--".date("Y-m-d H:i:s",time())."--".$uri."rn",FILE_APPEND);
$timepass=$timetem+$allowTime-$time;
die("Warning:".""."Sorry,you are forbided by refreshing frequently too much, Pls wait for ".$timepass." seconds to continue!");
}
}
}
}
if($yesno) $str.=$checkip.$checkuri.$time."1rn";
file_put_contents($file,$str);
?>