#!/bin/bash

check_and_fix_eth0_link()

{

date="`date '+%Y-%m-%d %H:%M:%S'`"

# step3 : if have ip, ping $dns

        lost_rate=`ping -c  -w  $dns -I $eth0 | grep 'packet loss' \

                                                | awk -F'packet loss' '{ print $1 }' \

                                                | awk '{ print $NF }' | sed 's/%//g'`

# step4: if ping dns failed, fix the link of $eth0

        if [ $lost_rate -eq  ]

        then

                echo "network_ok $date $dns $dev" >>/root/network_ok.log

        elif [ $lost_rate -le  ]

        then

                echo "network_error $date $dns $dev" >>/root/network_error.log

                ifconfig $usb0 down

                sleep

                ifconfig $usb0 up

        fi

}

eth0="eth0"

usb0="usb0"

dns="61.139.2.69"

touch /root/network_ok.log

touch /root/network_error.log

while [  ]

do

# step  : test if $eth0 have ip

    ipaddr=` /sbin/ifconfig $eth0 | grep "inet addr" | awk '{ print $2}' | awk -F: '{print $2}' `

    if [ ! -n "$ipaddr" ]

    then

# step2 : if have no ip, reset the $eth0, maybe the "udhcpc -i $eth0 ?"

            echo "    $0: NO IP Addr"

            /etc/init.d/networking restart

    else

            check_and_fix_eth0_link;

    fi

    sleep

done