keep_pptp_vpn.sh

#!/bin/sh


VPN_SERVER_IP=
REAL_SERVER_IP=
VPN_NAME=


usage()
{
    echo ""
    echo "usage:"
    echo "    `basename $0` -v vpn_server_ip -s real_server_ip -n vpn_name"
    echo ""
    echo "vpn_server_ip: pptp server local ip(in server's file '/etc/pptpd.conf'), eg: 7.0.0.1"
    echo "real_server_ip: server ip which pptp server installed on, eg: 120.92.5.82"
    echo "vpn_name: pptp client vpn name, eg: ksvpn82"
    echo ""
    
    exit 1
}


while getopts :v:s:n: opt
do
    case $opt in
        v)
            VPN_SERVER_IP=$OPTARG
            ;;
        s)
            REAL_SERVER_IP=$OPTARG
            ;;
        n)
            VPN_NAME=$OPTARG
            ;;
        \?)
            usage
            ;;
    esac
done


if [ -z "$VPN_SERVER_IP" ] || [ -z "$REAL_SERVER_IP" ] || [ -z "$VPN_NAME" ]; then
    echo "invalid arguments"
    usage
fi


while :
do
    echo "checking..."
    date --rfc-3339=seconds
    until ping -c 1 $VPN_SERVER_IP > /dev/null; do
        echo "can not connect to vpn server ip: $VPN_SERVER_IP"
        sudo poff $VPN_NAME
        #pptpsetup --delete ksvpn82
        
        until ping -c 1 $REAL_SERVER_IP > /dev/null; do
            echo "can not connect to real server ip: $REAL_SERVER_IP"
        done
        
        #pptpsetup --create ksvpn82 --server 120.92.5.82 --username wps --password kingsoft+ --encrypt --start
        sudo pon $VPN_NAME
        sleep 5
    done
    sleep 5
done