The function of automatically blocking the other party's IP when being attacked by CC or DDOS

This function is used to count how many times each visitor has visited in a short period of time. If the number of visits exceeds the limit, it returns TRUE. After that, you can use PHP to call linux's iptables to perform the blocking operation. I have used several I have actually tested DDOS tools and the results are very good.

By the way, by the way, I use files in the code to record the visitor IP and time. It is best not to use a database (and don’t be clever and save it in the session) ), and it’s best to put this file on the SSD hard drive. I won’t go into details about the reason. I guess everyone knows it

/**
    防止客戶端惡意重整
    用法:
        $isf5=Fun::isf5();
    返回:
        返回bool[true:對方在惡意重整;false:正常訪問]
/**/
public static function isf5(){
    $_f=Run.'_isf5';
    if(!file_exists($_f)){
        file_put_contents($_f,serialize(array()),LOCK_EX);
        chmod($_f,0777);
    }
    $arr=unserialize(file_get_contents($_f));
    $arr=(!is_array($arr)) ? array() : $arr;
 
    //清理掉10秒前訪問的用戶
    foreach($arr as $k=>$v){
        if($_ENV['now']-$v['t'] >= 10){
            unset($arr[$k]);
        }
    }
 
    $ip='_'.(self::cur('ip'));
 
    if(!isset($arr[$ip])){
        $arr[$ip]['n']=1;                       //1s內連線的次數
        $arr[$ip]['t']=$_ENV['now'];            //第1次訪問的時間
        file_put_contents($_f,serialize($arr),LOCK_EX);
        chmod($_f,0777);
        unset($_f,$arr,$ip);
        return FALSE;
    }else{
        if(!isset($arr[$ip]['t']) or !is_numeric($arr[$ip]['t'])){
            unset($arr[$ip]);
            file_put_contents($_f,serialize($arr),LOCK_EX);
            chmod($_f,0777);
            unset($_f,$arr,$ip);
            return FALSE;
        }
        if(($_ENV[&#39;now&#39;]-$arr[$ip][&#39;t&#39;]) <= 1){  //若距離上次訪問的時間沒有超過1s,則只累加次數
            $arr[$ip][&#39;n&#39;]+=1;
            if($arr[$ip][&#39;n&#39;]>=5){
                unset($_f,$arr,$ip);
                return TRUE;
            }else{
                file_put_contents($_f,serialize($arr),LOCK_EX);
                chmod($_f,0777);
                unset($_f,$arr,$ip);
                return FALSE;
            }
        }else{                                              //若距離上次訪問的時間已經超過1s,則重新計數
            $arr[$ip][&#39;n&#39;]=1;
            $arr[$ip][&#39;t&#39;]=$_ENV[&#39;now&#39;];
            file_put_contents($_f,serialize($arr),LOCK_EX);
            chmod($_f,0777);
            unset($_f,$arr,$ip);
            return FALSE;
        }
    }
    unset($_f,$arr,$ip);
    return FALSE;
}