php--防止DDos攻击代码

 <?php
 //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($ip."\r\n",$filehtarr))die("Warning:"."<br>"."Your IP address are forbided by some reason, IF you have any question Pls emill to shop@mydalle.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."\r\n",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.$time."1\r\n";
             elseif($numtem<$allowNum)$str.=$iptem.$uritem.$timetem.($numtem+1)."\r\n";
             else
             {
                 if(!file_exists($fileforbid)){$addforbidarr=array($ip."\r\n",time()."\r\n",1);file_put_contents($fileforbid,$addforbidarr);}
                 file_put_contents("log/forbided_ip.log",$ip."--".date("Y-m-d H:i:s",time())."--".$uri."\r\n",FILE_APPEND);
                 $timepass=$timetem+$allowTime-$time;
                 die("Warning:"."<br>"."Sorry,you are forbided by refreshing frequently too much, Pls wait for ".$timepass." seconds to continue!");
             }
         }
     }
 }
 if($yesno) $str.=$checkip.$checkuri.$time."1\r\n";
 file_put_contents($file,$str);
 ?>