【IT168 技术文档】

    基本原理:

　　通过过滤ip_conntrack表得到ESTABLISHED状态过多的ip, 然后用iptabels封掉一段时间,同时用hping工具将这些ip从表中清理掉,最后将被封的ip和一些其他信息写到一个html页中,做简单的发布。

　　关于hping:

　　下载: http://www.hping.org/download.html
　　安装: ./configure;make;make install
　　相关联接: http://chinaunix.net/jh/4/367999.html

　　默认功能:

　　1、当一个ip在ip_conntrack表中的ESTABLISHED状态在30-50之间时, 此ip被封10分钟,同时在ip_conntrack表中的记录被清除;50-100之间封15分钟,同时清表;100以上封30分钟,同时清表,

　　2、然后生成web页

/var/www/html/wwy/drop/index.html --- 显示被封的ip, 和cpu状态等信息
/var/www/html/wwy/all/index.html --- 每一个ip的连接情况

　　3、生成简单的日志

/tmp/killip/tmp.log.txt

　　使用方法:

　　1、需要安装hping

　　2、建议将脚本放到计划任务中

　　3、建议安装并开启apache, 为支持简单的web发布,默认为 http://127.0.0.1/l/wwy/drop/index.htm

　　4、如果表的大小大于20mb请慎用

　　代码:

#!/bin/bash
#
#---------------------------------------------------------------------------------------
#Scrip name: killip, base on ip_conntrack, write by wwy.
#---------------------------------------------------------------------------------------

cpu=`sar -u 1 1 | awk '{print $7}' | tail -1`%
#
while [ "`pidof sleep`" ];do
        echo "she is running, sorry"
        exit 1
done
if [ ! "`lsmod | grep ip_conntrack`" ]; then
         modprobe ip_conntrack
fi

####################################
##---------------------- functions -----------------------------##
####################################

function make_clr ...{
        while read clr33;do
                cat /tmp/tmp111.txt | grep $clr33 >> /tmp/tmp33-3-clr.txt
        done < /tmp/tmp33-3.txt
        while read clr22;do
                cat /tmp/tmp111.txt | grep $clr22 >> /tmp/tmp33-2-clr.txt
        done < /tmp/tmp33-2.txt
        while read clr11;do
                cat /tmp/tmp111.txt | grep $clr11 >> /tmp/tmp33-1-clr.txt
        done < /tmp/tmp33-1.txt
}
function clr_conns ...{
        S_IP=$1
        D_IP=$2
        S_PORT=$3
        D_PORT=$4
        hping2 $D_IP -R -s $S_PORT -p $D_PORT -a $S_IP -k -c 1 >/dev/null 2>/dev/null &
}
function kill() ...{
        SLEEP_TIME=$1
        CLR_LIST=$2
        BLACK_LIST=$3
        while read blackip;do
                iptables -I FORWARD 2 -i eth0 -s $blackip/32  -j DROP
        done < $BLACK_LIST
        sleep $SLEEP_TIME
        #-----------------------------------#
        while read clr3;do
                clr_conns $clr3
        done < $CLR_LIST
        #-----------------------------------#
        sleep 1
        while read reblackip;do
                iptables -D FORWARD -i eth0 -s $reblackip/32  -j DROP
        done < $BLACK_LIST

}
#####################################
##--------------- To make a "black list" ----------------------##
#####################################

echo > /tmp/tmp11.txt
echo > /tmp/tmp111.txt
echo > /tmp/ip_conntrack.tmp
echo > /tmp/tmp33-3-clr.txt
echo > /tmp/tmp33-2-clr.txt
echo > /tmp/tmp33-1-clr.txt
echo > /tmp/tmp22-3.txt
echo > /tmp/tmp22-2.txt
echo > /tmp/tmp22-1.txt
echo > /tmp/tmp33-3.txt
echo > /tmp/tmp33-2.txt
echo > /tmp/tmp33-1.txt
if [ ! -e /var/www/html/wwy/index.html ];then
        mkdir /var/www/html/wwy/
        mkdir /var/www/html/wwy/all
        mkdir /var/www/html/wwy/drop
5B
        touch /var/www/html/wwy/index.html
fi
#----------------------------------------------------------------------------#
echo -e "cp /proc/net/ip_conntrack /tmp/ip_conntrack.tmp ......\c"
cp /proc/net/ip_conntrack /tmp/ip_conntrack.tmp
echo -e "done!\n"
sleep 1
#----------------------------------------------------------------------------#
wc=`cat /tmp/ip_conntrack.tmp|grep ESTABLISHED|awk -F= '{print $2,$3,$4,$5}'|grep ^172. |sort|awk '{print $1,$3,$5,$7}'|tee /tmp/tmp111.txt|awk '{print $1}'|uniq -c|tee /tmp/tmp11.txt|wc -l`
date=`date '+%m/%d %H:%M'`
cpu2=`sar -u 1 1 | awk '{print $7}' | tail -1`%
date2=`date '+%H'`
#----------------------------------------------------------------------------#
sleep 1
#----------------------------------------------------------------------------#
#if [ "$wc" -gt 2500 ] && [ "$date2" -gt 10 ]
if [ "$wc" -ge 0 ]
then
#------------------------------
        awk '{$1}{if ($1>30 && $1<50) print $2}' /tmp/tmp11.txt > /tmp/tmp22-1.txt
        awk '{$1}{if ($1>=50 && $1<100) print $2}' /tmp/tmp11.txt > /tmp/tmp22-2.txt
        awk '{$1}{if ($1>=100) print $2}' /tmp/tmp11.txt > /tmp/tmp22-3.txt
        cut -c1-15 /tmp/tmp22-1.txt > /tmp/tmp33-1.txt
        cut -c1-15 /tmp/tmp22-2.txt > /tmp/tmp33-2.txt
        cut -c1-15 /tmp/tmp22-3.txt > /tmp/tmp33-3.txt
        wcblackip1=`cat /tmp/tmp33-1.txt | wc -l`
        wcblackip2=`cat /tmp/tmp33-2.txt | wc -l`
        wcblackip3=`cat /tmp/tmp33-3.txt | wc -l`

######################################
##---------------- To make a index.html -----------------------##
######################################

        echo "<b>If the total IPs >2500 <font color=\"#ff0000\">(total $wc at $date)</font> AND if:</b>" > /var/www/html/wwy/drop/index.html
        echo "<p>you connect <b>\">100\"</b>, you ip will be killed in <b>30min</b>.</p>" >>/var/www/html/wwy/drop/index.html
        echo "<p>you connect <b>\"50-100\"</b>, you ip will be killed in <b>15min</b>.</p>" >>/var/www/html/wwy/drop/index.html
        echo "<p>you connect <b>\"30-50\"</b>, you ip will be killed in <b>10min</b>.</p>" >>/var/www/html/wwy/drop/index.html
        echo "<hr color=\"#ff8000\">" >> /var/www/html/wwy/drop/index.html
        echo "<p><b><font color=\"#ff0000\">These IPs (total $wcblackip3 + $wcblackip2 + $wcblackip1) were killed, at <font size=5>$date</font></font>  <a href=../all>(look-up all IPs)</a></b></p>" >> /var/www/html/wwy/drop/index.html
        awk '{$1}{if ($1>=100) print $1, $2}' /tmp/tmp11.txt|sort -nr|awk '{print "<p>""<font color=\"#ff0000\">"$1"</font>""\t","<b>"$2"</b>""\t""kill 30min""</p>"}' >> /var/www/html/wwy/drop/index.html
        awk '{$1}{if ($1>=50 && $1<100) print $1, $2}' /tmp/tmp11.txt|sort -nr|awk '{print "<p>"$1"\t","<b>"$2"</b>""\t""kill 15min""</p>"}' >> /var/www/html/wwy/drop/index.html
        awk '{$1}{if ($1>30 && $1<50) print $1, $2}' /tmp/tmp11.txt|sort -nr|awk '{print "<p>"$1"\t","<b>"$2"</b>""\t""kill 10min""</p>"}' >> /var/www/html/wwy/drop/index.html
        echo "<p><b>You can \"ctrl + F\" to find your ip's connects.(total $wc IPs at $date)</b></p>" > /var/www/html/wwy/all/index.html
        echo "<p><a href=../drop> <-- back </a></p>" >> /var/www/html/wwy/all/index.html
        cat /tmp/tmp11.txt | sort -nr | awk '{print "<p>"$1"\t",$2"\t""</p>"}' >> /var/www/html/wwy/all/index.html

#####################################
##----------------- Use iptables to DROP ---------------------##
#####################################

        make_clr
        if [ -s /tmp/tmp33-3.txt ];then
                kill 30m /tmp/tmp33-3-clr.txt /tmp/tmp33-3.txt &
                sleep 1s
        fi
        if [ -s /tmp/tmp33-2.txt ];then
                kill 15m /tmp/tmp33-2-clr.txt /tmp/tmp33-2.txt &
                sleep 1s
        fi
        if [ -s /tmp/tmp33-1.txt ];then
                kill 10m /tmp/tmp33-1-clr.txt /tmp/tmp33-1.txt &
                sleep 1s
        fi

#-------------------------------
elif [ "$date2" -lt 5 ] && [ "$date2" -gt 3 ]
then
        while read clrall;do
                clr_conns $clrall
        done < /tmp/tmp111.txt
        echo "clr at $date " >> /tmp/killip/tmp.log.txt
fi

#####################################
##------------------- make system log ------------------------##
#####################################
if [ ! -e /tmp/killip/tmp.log.txt ]; then
        mkdir /tmp/killip
        touch /tmp/killip/tmp.log.txt
fi
echo "$wc $date $cpu $cpu2 $wcblackip3 + $wcblackip2 + $wcblackip1" >> /tmp/killip/tmp.log.txt