博主呓语:

shell脚本分析linux系统的网络实时流量和连接情况

Posted by 破冰 on 2016-3-4 17:37 Friday

此脚本包含的功能有:
实时监控任意网卡的流量
统计10秒内平均流量
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。
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。
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。
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。
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。
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。

脚本内容:

#!/bin/bash

#write by zhumaohai(admin#centos.bz)
#author blog: www.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 "#################### ${soft} setting ####################\n\n"
    for ((i=1;i<=${#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 "\033[0;0H"
        #清屏并打印Now Peak
        [[ $clear == true ]] && printf "\033[2J" && echo "$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 "\033[2;1H"
        #清除当前行
        printf "\033[K"   
        printf "%-20s %-20s\n" "Receive:  $(bit_to_human_readable $eth_in)" "$(bit_to_human_readable $eth_in_peak)"
        #清除当前行
        printf "\033[K"
        printf "%-20s %-20s\n" "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 "\033[32mnetwork device $eth average traffic in 10s: \033[0m"
    echo "$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]+\))(.*)#\1\n    \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 "\033[32maverage traffic in 10s base on server port: \033[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 %d\n",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 $d)/s"
    done
    echo -ne "\033[11A"
    echo -ne "\033[50C"
    echo -e "\033[32maverage traffic in 10s base on client port: \033[0m"
    awk -F'[ .:]+' -v regTcpdump=$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 %d\n",line,sum[line]}}' /tmp/tcpdump | \
    sort -k 4 -nr | head -n 10 | while read a b c d;do
            echo -ne "\033[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 "\033[32mtop 10 ip average traffic in 10s base on server: \033[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 %d\n",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 $d)/s"
    done
    echo -ne "\033[11A"
    echo -ne "\033[50C"
    echo -e "\033[32mtop 10 ip average traffic in 10s base on client: \033[0m"
    awk -F'[ .:]+' -v regTcpdump=$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 %d\n",line,sum[line]}}' /tmp/tcpdump | \
    sort -k 4 -nr | head -n 10 | while read a b c d;do
        echo -ne "\033[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 "$regSS" > /tmp/ss
    echo -e "\033[32mconnection state count: \033[0m"
    awk 'NR>1{sum[$(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 "\033[32mconnection state count by port base on server: \033[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 "\033[11A"
    echo -ne "\033[50C"
    echo -e "\033[32mconnection state count by port base on client: \033[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 "\033[50C"$0}'   
    echo   
    #统计端口为80且状态为ESTAB连接数最多的前10个IP
    echo -e "\033[32mtop 10 ip ESTAB state count at port 80: \033[0m"
    cat /tmp/ss | grep ESTAB | awk -F'[: ]+' '{sum[$(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 "\033[32mtop 10 ip SYN-RECV state count at port 80: \033[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
脚本执行结果:

1) real time traffic.
2) traffic and connection overview.

please input your select(ie 1): 2
please wait for 10s to generate network data...
network device eth0 average traffic in 10s: 
eth0 Receive: 2.3Kb/s
eth0 Transmit: 684b/s                             average traffic in 10s base on client port: 
                                                  192.168.158.133:37065 > server 438b/s
average traffic in 10s base on server port:       server > 22.147.117.ICMP:echo 268b/s
clients > 192.168.158.132:4506 480b/s             server > 168.158.132.ICMP:echo 268b/s
192.168.158.132:> > clients 268b/s                server > 192.168.158.255:138 183b/s
172.22.147.117:> > clients 268b/s                 server > 192.168.158.133:37065 98b/s
clients > 192.168.158.132:3358 238b/s             192.168.159.52:47628 > server 87b/s
192.168.158.152:138 > clients 183b/s              192.168.159.52:47627 > server 87b/s
192.168.158.132:4506 > clients 140b/s             server > 192.168.162.16:62501 73b/s
192.168.158.132:3358 > clients 100b/s             server > 192.168.159.52:47628 50b/s
192.168.158.132:22 > clients 73b/s                server > 192.168.159.52:47627 50b/s

top 10 ip average traffic in 10s base on server:  top 10 ip average traffic in 10s base on client: 
192.168.158.133 > 192.168.158.132:4506 438b/s     192.168.158.133:37065 > 192.168.158.132 438b/s
192.168.158.132:> > 22.147.117.ICMP 268b/s        192.168.158.132 > 22.147.117.ICMP:echo 268b/s
172.22.147.117:> > 168.158.132.ICMP 268b/s        172.22.147.117 > 168.158.132.ICMP:echo 268b/s
192.168.158.152:138 > 192.168.158.255 183b/s      192.168.158.152 > 192.168.158.255:138 183b/s
192.168.159.52 > 192.168.158.132:3358 174b/s      192.168.158.132 > 192.168.158.133:37065 98b/s
192.168.158.132:3358 > 192.168.159.52 100b/s      192.168.159.52:47628 > 192.168.158.132 87b/s
192.168.158.132:4506 > 192.168.158.133 98b/s      192.168.159.52:47627 > 192.168.158.132 87b/s
192.168.158.132:22 > 192.168.162.16 73b/s         192.168.158.132 > 192.168.162.16:62501 73b/s
192.168.162.16 > 192.168.158.132:3358 64b/s       192.168.158.132 > 192.168.159.52:47628 50b/s
192.168.158.132:4506 > 192.168.146.149 41b/s      192.168.158.132 > 192.168.159.52:47627 50b/s

connection state count: 
ESTAB 68                                          connection state count by port base on client: 
FIN-WAIT-2 1                                      ESTAB ::ffff:192.168.158.132:3358 2
                                                  FIN-WAIT-2 192.168.162.16:46210 1
connection state count by port base on server:    ESTAB 192.168.195.54:50219 1
ESTAB 192.168.158.132:4506 27                     ESTAB 192.168.195.54:35346 1
ESTAB 192.168.158.132:4505 27                     ESTAB 192.168.195.53:55307 1
ESTAB 192.168.158.132:3358 9                      ESTAB 192.168.195.53:40342 1
ESTAB 192.168.158.132:22 3                        ESTAB 192.168.195.52:47008 1
FIN-WAIT-2 192.168.158.132:3358 1                 ESTAB 192.168.195.52:35396 1
ESTAB ::ffff:192.168.158.132:35804 1              ESTAB 192.168.195.51:48180 1
ESTAB ::ffff:192.168.158.132:35803 1              ESTAB 192.168.195.51:40585 1

top 10 ip ESTAB state count at port 80: 
192.168.162.16 7
192.168.159.91 4
192.168.159.52 4
192.168.158.132 4
192.168.195.54 2
192.168.195.53 2
192.168.195.52 2
192.168.195.51 2
192.168.195.50 2
192.168.195.49 2

top 10 ip SYN-RECV state count at port 80: 
用到的网络分析工具:

tcpdump:此脚本用tcpdump来统计基于ip或基于端口的流量。
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。
/proc/net/dev,用来统计指定网卡的流量。

标签:

发表评论: