PHP Anti-DDoS attack instance code

The PHP anti-DDoS attack instance code is as follows:

<?php//Query prohibit 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 is forbided by some reason and IF you had any question Pls Emill to shop@mydalle.com! "); Join the Forbidden 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);}} }}//anti-Refresh $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;//Anti-Refresh Time $allowNum =10;//anti-refresh times $uri =$_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 is 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);?>