#!/bin/bash
##取得参数$1为并发阈值，若留空则默认允许单IP最大50并发(实际测试发现，2M带宽，十来个并发服务器就已经无法访问了！)
if [[ -z $1 ]];then
        num=50
else
        num=$1
fi
 
#巧妙的进入到脚本工作目录
cd $(cd $(dirname $BASH_SOURCE) && pwd)
 
#请求检查, 判断及拉黑主功能函数
function check(){
        iplist=`netstat -an |grep ^tcp.*:80|egrep -v 'LISTEN|127.0.0.1'|awk -F"[ ]+|[:]" '{print $6}'|sort|uniq -c|sort -rn|awk -v str=$num '{if ($1>str){print $2}}'`
        if [[ ! -z $iplist ]];
                then
                >./black_ip.txt
                for black_ip in $iplist
                do
                        #白名单过滤中已取消IP段的判断功能，可根据需要自行修改以下代码
                        #exclude_ip=`echo $black_ip | awk -F"." '{print $1"."$2"."$3}'`
                        #grep -q $exclude_ip ./white_ip.txt
                        grep -q $black_ip ./white_ip.txt
                        if [[ $? -eq 0 ]];then
                                echo "$black_ip (white_ip)" >>./black_ip.txt
                        else
                                echo $black_ip >>./black_ip.txt     
                                iptables -nL | grep $black_ip ||(iptables -I INPUT -s $black_ip -j DROP & echo "$black_ip  `date +%Y-%m-%H:%M:%S`">>./deny.log & echo 1 >./sendmail)
                        fi
                done
                #存在并发超过阀值的单IP就发送邮件
                if [[ `cat ./sendmail` == 1 ]];then sendmsg;fi
        fi
}
 
#发邮件函数
function sendmsg(){
        netstat -nutlp | grep "sendmail" >/dev/null 2>&1 || /etc/init.d/sendmail start >/dev/null 2>&1
        echo -e "From: xxxxxx@qq.com\nTo:xxx@163.com\nSubject:Someone Attacking your system!!\nIts Ip is" >./message
        cat ./black_ip.txt >>./message
        /usr/sbin/sendmail -f xxxxx@qq.com -t xxx@163.com -i <./message
        >./sendmail
}
 
#
while true
do
        check
        #每隔10s检查一次，时间可格局需要自定义
        sleep 10
done