PHP攻击网站防御代码-以及攻击代码反译

无意中看到的，留着以后研究

<?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 [e-mail]!");  //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);  ?>