SSH PPP VPN

#!/bin/sh
#SERVER_HOSTNAME=" gaius -p 22"
test $# -ne 4 && ( echo  $0 'start|stop PORT IP NETRANGE' ; exit 1 )

SERVER_HOSTNAME=" $3 -p $2"
LOCAL_NET=192.168.240.0/20
REMOTE_NET="$4"
SERVER_USERNAME=root
########
SERVER_IFIPADDR=172.29.29.1
CLIENT_IFIPADDR=172.29.29.3
LOCAL_SSH_OPTS="-P"

PATH=/usr/local/sbin:/sbin:/bin:/usr/sbin:/usr/bin:/usr/bin/X11/:

PPPD=/usr/sbin/pppd
SSH=/usr/bin/ssh
ROUTE=/sbin/route
ADD_FORT="/sbin/sysctl  -w  net.ipv4.ip_forward=1"
DEl_FORT="/sbin/sysctl  -w  net.ipv4.ip_forward=0"
ADD_SNAT="/sbin/iptables -t nat -A POSTROUTING -s $LOCAL_NET -j MASQUERADE -o eth0"
DEL_SNAT="/sbin/iptables -t nat -D POSTROUTING -s $LOCAL_NET -j MASQUERADE -o eth0"

if ! test -f $PPPD  ; then echo "can't find $PPPD";  exit 3; fi
if ! test -f $SSH   ; then echo "can't find $SSH";   exit 4; fi


case "$1" in
  start)
     echo -n "Starting vpn to $SERVER_HOSTNAME: "
    ${PPPD} updetach noauth passive pty "${SSH} ${LOCAL_SSH_OPTS} ${SERVER_HOSTNAME} -l${SERVER_USERNAME} -o Batchmode=yes ${PPPD} nodetach notty noauth" ipparam vpn ${CLIENT_IFIPADDR}:${SERVER_IFIPADDR}
     ${SSH} ${LOCAL_SSH_OPTS} ${SERVER_HOSTNAME} -l${SERVER_USERNAME} ${ROUTE} add -net ${LOCAL_NET} gw ${CLIENT_IFIPADDR}
     ${ROUTE} add -net ${REMOTE_NET} gw ${SERVER_IFIPADDR}
     ${SSH} ${LOCAL_SSH_OPTS} ${SERVER_HOSTNAME} -l${SERVER_USERNAME} ${ADD_FORT}
     ${SSH} ${LOCAL_SSH_OPTS} ${SERVER_HOSTNAME} -l${SERVER_USERNAME} ${ADD_SNAT}

    # echo "connected."
    ;;

  stop)
        # echo -n "Stopping vpn to $SERVER_HOSTNAME: "
        ${SSH} ${LOCAL_SSH_OPTS} ${SERVER_HOSTNAME} -l${SERVER_USERNAME} ${DEL_SNAT}
        PID=`ps ax | grep "${SSH} ${LOCAL_SSH_OPTS} ${SERVER_HOSTNAME} -l${SERVER_USERNAME} -o" | grep -v ' passive ' | grep -v 'grep ' | awk '{print $1}'`
        if [ "${PID}" != "" ]; then
          kill $PID
          echo "disconnected."
        else
          echo "Failed to find PID for the connection"
        fi
    ;;

  config)
    echo "SERVER_HOSTNAME=$SERVER_HOSTNAME"
    echo "SERVER_USERNAME=$SERVER_USERNAME"
    echo "SERVER_IFIPADDR=$SERVER_IFIPADDR"
    echo "CLIENT_IFIPADDR=$CLIENT_IFIPADDR"
  ;;
esac