一个强大的网络分析shell脚本分享(实时流量、连接统计)

介绍一个强大的分析网络的shell脚本，此脚本是从EZHTTP拆分出来的，觉得有必要单独介绍下。

脚本运行效果截图：

此脚本包含的功能有：

1、实时监控任意网卡的流量
2、统计10秒内平均流量
3、统计每个端口在10秒内的平均流量，基于客户端和服务端端口统计。可以看出哪些端口占流量比较大，对于web服务器，一般是80端口。其它端口受到攻击时，也有可能其它端口流量比较大。所以此功能可以帮助我们端口流量是否正常。
4、统计在10s内占用带宽最大的前10个ip。此项功能可以帮助我们来查出是否有恶意占用带宽的ip。
5、统计连接状态。此项功能可以让我们看出哪些连接状态比较大。如果SYN-RECV状态比较多的话，有可以受到半连接攻击。如果ESTABLISED非常大，但通过日志发现没有那么多请求，或者通过tcpdump发现大量ip只建立连接不请求数据的话，可能是受到了全连接攻击，这时候如果你使用的是nginx服务器，可以在配置文件增加listen 80 deferred来防止。
6、统计各端口连接状态。当可能受到攻击时，此项功能可以帮助我们发现是哪个端口受到攻击。
7、统计端口为80且状态为ESTAB连接数最多的前10个IP。此项功能可以帮助我们来找出创建连接过多的Ip，进而屏蔽。
8、统计端口为80且状态为SYN-RECV连接数最多的前10个IP。当受到半连接攻击时，此项功能可以帮助我们找到恶意ip。

用到的网络分析工具：

1、tcpdump:此脚本用tcpdump来统计基于ip或基于端口的流量。
2、ss： 此脚本用ss命令来统计连接状态，实际使用发现ss比netstat高效得多。
3、/proc/net/dev，用来统计指定网卡的流量。
脚本下载地址：https://www.centos.bz/wp-content/uploads/2014/06/network-analysis.sh
下面贴出完整的脚本：

#!/bin/bash

#write by zhumaohai(admin#centos.bz)

#显示菜单(单选)

display_menu(){

local soft=$1

local prompt="which ${soft} you'd select: "

eval local arr=(${${soft}_arr[@]})

while true

do

    echo -e "#################### ${soft} setting ####################nn"

    for ((i=1;i<=${#arr[@]};i++ )); do echo -e "$i) ${arr[$i-1]}"; done

    echo

    read -p "${prompt}" $soft

    eval local select=$$soft

    if [ "$select" == "" ] || [ "${arr[$soft-1]}" == ""  ];then

        prompt="input errors,please input a number: "

    else

        eval $soft=${arr[$soft-1]}

        eval echo "your selection: $$soft"             

        break

    fi

done

}

#把带宽bit单位转换为人类可读单位

bit_to_human_readable(){

    #input bit value

    local trafficValue=$1

    if [[ ${trafficValue%.*} -gt 922 ]];then

        #conv to Kb

        trafficValue=`awk -v value=$trafficValue 'BEGIN{printf "%0.1f",value/1024}'`

        if [[ ${trafficValue%.*} -gt 922 ]];then

            #conv to Mb

            trafficValue=`awk -v value=$trafficValue 'BEGIN{printf "%0.1f",value/1024}'`

            echo "${trafficValue}Mb"

        else

            echo "${trafficValue}Kb"

        fi

    else

        echo "${trafficValue}b"

    fi

}

#判断包管理工具

check_package_manager(){

    local manager=$1

    local systemPackage=''

    if cat /etc/issue | grep -q -E -i "ubuntu|debian";then

        systemPackage='apt'

    elif cat /etc/issue | grep -q -E -i "centos|red hat|redhat";then

        systemPackage='yum'

    elif cat /proc/version | grep -q -E -i "ubuntu|debian";then

        systemPackage='apt'

    elif cat /proc/version | grep -q -E -i "centos|red hat|redhat";then

        systemPackage='yum'

    else

        echo "unkonw"

    fi

    if [ "$manager" == "$systemPackage" ];then

        return 0

    else

        return 1

    fi   

}

#实时流量

realTimeTraffic(){

    local eth=""

    local nic_arr=(`ifconfig | grep -E -o "^[a-z0-9]+" | grep -v "lo" | uniq`)

    local nicLen=${#nic_arr[@]}

    if [[ $nicLen -eq 0 ]]; then

        echo "sorry,I can not detect any network device,please report this issue to author."

        exit 1

    elif [[ $nicLen -eq 1 ]]; then

        eth=$nic_arr

    else

        display_menu nic

        eth=$nic

    fi   

    local clear=true

    local eth_in_peak=0

    local eth_out_peak=0

    local eth_in=0

    local eth_out=0

    while true;do

        #移动光标到0:0位置

        printf "33[0;0H"

        #清屏并打印Now Peak

        [[ $clear == true ]] && printf "33[2J" && echo "$eth--------Now--------Peak-----------"

        traffic_be=(`awk -v eth=$eth -F'[: ]+' '{if ($0 ~eth){print $3,$11}}' /proc/net/dev`)

        sleep 2

        traffic_af=(`awk -v eth=$eth -F'[: ]+' '{if ($0 ~eth){print $3,$11}}' /proc/net/dev`)

        #计算速率

        eth_in=$(( (${traffic_af[0]}-${traffic_be[0]})*8/2 ))

        eth_out=$(( (${traffic_af[1]}-${traffic_be[1]})*8/2 ))

        #计算流量峰值

        [[ $eth_in -gt $eth_in_peak ]] && eth_in_peak=$eth_in

        [[ $eth_out -gt $eth_out_peak ]] && eth_out_peak=$eth_out

        #移动光标到2:1

        printf "33[2;1H"

        #清除当前行

        printf "33[K"   

        printf "%-20s %-20sn" "Receive:  $(bit_to_human_readable $eth_in)" "$(bit_to_human_readable $eth_in_peak)"

        #清除当前行

        printf "33[K"

        printf "%-20s %-20sn" "Transmit: $(bit_to_human_readable $eth_out)" "$(bit_to_human_readable $eth_out_peak)"

        [[ $clear == true ]] && clear=false

    done

}

#流量和连接概览

trafficAndConnectionOverview(){

    if ! which tcpdump > /dev/null;then

        echo "tcpdump not found,going to install it."

        if check_package_manager apt;then

            apt-get -y install tcpdump

        elif check_package_manager yum;then

            yum -y install tcpdump

        fi

    fi

    local reg=""

    local eth=""

    local nic_arr=(`ifconfig | grep -E -o "^[a-z0-9]+" | grep -v "lo" | uniq`)

    local nicLen=${#nic_arr[@]}

    if [[ $nicLen -eq 0 ]]; then

        echo "sorry,I can not detect any network device,please report this issue to author."

        exit 1

    elif [[ $nicLen -eq 1 ]]; then

        eth=$nic_arr

    else

        display_menu nic

        eth=$nic

    fi

    echo "please wait for 10s to generate network data..."

    echo

    #当前流量值

    local traffic_be=(`awk -v eth=$eth -F'[: ]+' '{if ($0 ~eth){print $3,$11}}' /proc/net/dev`)

    #tcpdump监听网络

    tcpdump -v -i $eth -tnn > /tmp/tcpdump_temp 2>&1 &

    sleep 10

    clear

    kill `ps aux | grep tcpdump | grep -v grep | awk '{print $2}'`

    #10s后流量值

    local traffic_af=(`awk -v eth=$eth -F'[: ]+' '{if ($0 ~eth){print $3,$11}}' /proc/net/dev`)

    #打印10s平均速率

    local eth_in=$(( (${traffic_af[0]}-${traffic_be[0]})*8/10 ))

    local eth_out=$(( (${traffic_af[1]}-${traffic_be[1]})*8/10 ))

    echo -e "33[32mnetwork device $eth average traffic in 10s: 33[0m"

    echo "$eth Receive: $(bit_to_human_readable $eth_in)/s"

    echo "$eth Transmit: $(bit_to_human_readable $eth_out)/s"

    echo
    local regTcpdump=$(ifconfig | grep -A 1 $eth | awk -F'[: ]+' '$0~/inet addr:/{printf $4"|"}' | sed -e 's/|$//' -e 's/^/(/' -e 's/$/)\\.[0-9]+:/')

    #新旧版本tcpdump输出格式不一样,分别处理

    if awk '/^IP/{print;exit}' /tmp/tcpdump_temp | grep -q ")$";then

        #处理tcpdump文件

        awk '/^IP/{print;getline;print}' /tmp/tcpdump_temp > /tmp/tcpdump_temp2

    else

        #处理tcpdump文件

        awk '/^IP/{print}' /tmp/tcpdump_temp > /tmp/tcpdump_temp2

        sed -i -r 's#(.*: [0-9]+))(.*)#1n    2#' /tmp/tcpdump_temp2

    fi

    awk '{len=$NF;sub(/)/,"",len);getline;print $0,len}' /tmp/tcpdump_temp2 > /tmp/tcpdump
    #统计每个端口在10s内的平均流量

    echo -e "33[32maverage traffic in 10s base on server port: 33[0m"

    awk -F'[ .:]+' -v regTcpdump=$regTcpdump '{if ($0 ~ regTcpdump){line="clients > "$8"."$9"."$10"."$11":"$12}else{line=$2"."$3"."$4"."$5":"$6" > clients"};sum[line]+=$NF*8/10}END{for (line in sum){printf "%s %dn",line,sum[line]}}' /tmp/tcpdump | 

    sort -k 4 -nr | head -n 10 | while read a b c d;do

        echo "$a $b $c $(bit_to_human_readable $d)/s"

    done

    echo -ne "33[11A"

    echo -ne "33[50C"

    echo -e "33[32maverage traffic in 10s base on client port: 33[0m"

    awk -F'[ .:]+' -v regTcpdump=$regTcpdump '{if ($0 ~ regTcpdump){line=$2"."$3"."$4"."$5":"$6" > server"}else{line="server > "$8"."$9"."$10"."$11":"$12};sum[line]+=$NF*8/10}END{for (line in sum){printf "%s %dn",line,sum[line]}}' /tmp/tcpdump | 

    sort -k 4 -nr | head -n 10 | while read a b c d;do

            echo -ne "33[50C"

            echo "$a $b $c $(bit_to_human_readable $d)/s"

    done   

    echo
    #统计在10s内占用带宽最大的前10个ip

    echo -e "33[32mtop 10 ip average traffic in 10s base on server: 33[0m"

    awk -F'[ .:]+' -v regTcpdump=$regTcpdump '{if ($0 ~ regTcpdump){line=$2"."$3"."$4"."$5" > "$8"."$9"."$10"."$11":"$12}else{line=$2"."$3"."$4"."$5":"$6" > "$8"."$9"."$10"."$11};sum[line]+=$NF*8/10}END{for (line in sum){printf "%s %dn",line,sum[line]}}' /tmp/tcpdump | 

    sort -k 4 -nr | head -n 10 | while read a b c d;do

        echo "$a $b $c $(bit_to_human_readable $d)/s"

    done

    echo -ne "33[11A"

    echo -ne "33[50C"

    echo -e "33[32mtop 10 ip average traffic in 10s base on client: 33[0m"

    awk -F'[ .:]+' -v regTcpdump=$regTcpdump '{if ($0 ~ regTcpdump){line=$2"."$3"."$4"."$5":"$6" > "$8"."$9"."$10"."$11}else{line=$2"."$3"."$4"."$5" > "$8"."$9"."$10"."$11":"$12};sum[line]+=$NF*8/10}END{for (line in sum){printf "%s %dn",line,sum[line]}}' /tmp/tcpdump | 

    sort -k 4 -nr | head -n 10 | while read a b c d;do

        echo -ne "33[50C"

        echo "$a $b $c $(bit_to_human_readable $d)/s"

    done
    echo

    #统计连接状态

    local regSS=$(ifconfig | grep -A 1 $eth | awk -F'[: ]+' '$0~/inet addr:/{printf $4"|"}' | sed -e 's/|$//')

    ss -an | grep -v -E "LISTEN|UNCONN" | grep -E "$regSS" > /tmp/ss

    echo -e "33[32mconnection state count: 33[0m"

    awk 'NR>1{sum[$(NF-4)]+=1}END{for (state in sum){print state,sum[state]}}' /tmp/ss | sort -k 2 -nr

    echo

    #统计各端口连接状态

    echo -e "33[32mconnection state count by port base on server: 33[0m"

    awk 'NR>1{sum[$(NF-4),$(NF-1)]+=1}END{for (key in sum){split(key,subkey,SUBSEP);print subkey[1],subkey[2],sum[subkey[1],subkey[2]]}}' /tmp/ss | sort -k 3 -nr | head -n 10   

    echo -ne "33[11A"

    echo -ne "33[50C"

    echo -e "33[32mconnection state count by port base on client: 33[0m"

    awk 'NR>1{sum[$(NF-4),$(NF)]+=1}END{for (key in sum){split(key,subkey,SUBSEP);print subkey[1],subkey[2],sum[subkey[1],subkey[2]]}}' /tmp/ss | sort -k 3 -nr | head -n 10 | awk '{print "33[50C"$0}'   

    echo   

    #统计端口为80且状态为ESTAB连接数最多的前10个IP

    echo -e "33[32mtop 10 ip ESTAB state count at port 80: 33[0m"

    cat /tmp/ss | grep ESTAB | awk -F'[: ]+' '{sum[$(NF-2)]+=1}END{for (ip in sum){print ip,sum[ip]}}' | sort -k 2 -nr | head -n 10

    echo

    #统计端口为80且状态为SYN-RECV连接数最多的前10个IP

    echo -e "33[32mtop 10 ip SYN-RECV state count at port 80: 33[0m"

    cat /tmp/ss | grep -E "$regSS" | grep SYN-RECV | awk -F'[: ]+' '{sum[$(NF-2)]+=1}END{for (ip in sum){print ip,sum[ip]}}' | sort -k 2 -nr | head -n 10

}

main(){

    while true; do

        echo -e "1) real time traffic.n2) traffic and connection overview.n"

        read -p "please input your select(ie 1): " select

        case  $select in

            1) realTimeTraffic;break;;

            2) trafficAndConnectionOverview;break;;

            *) echo "input error,please input a number.";;

        esac

    done   

}

main