多出口断线自动切换

#!/bin/sh
# 检查网络连接并设置TUNDEV
TUNDEV=""
VPN_CONN=`ifconfig | grep 'pptp-vpn '`
VPN_CONN1=`ifconfig | grep 'pptp-vpn1 '`
VPN_CONN2=`ifconfig | grep 'pptp-vpn2 '`
if [ ! -z "$VPN_CONN" ]; then
    TUNDEV="pptp-vpn"
elif [ ! -z "$VPN_CONN1" ]; then
        TUNDEV="pptp-vpn1"
elif [ ! -z "$VPN_CONN2" ]; then
        TUNDEV="pptp-vpn2"
fi

＃根据在线设备，设置路由
if [ "$TUNDEV" == "" ]; then
       ip rule del table vpn
else
        ip route del 8.8.8.8
    ip route flush table vpn 2>/dev/null
    ip rule del table vpn 2>/dev/null

    ip route add 8.8.8.8 dev $TUNDEV
        ip rule add fwmark 999 table vpn
        ip route add default dev $TUNDEV table vpn
fi