#!/usr/bin/env python
#
# Copyright 2006 sense.lab e.V.
# 
# This file is part of the CryptoBox.
#
# The CryptoBox is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
# 
# The CryptoBox is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with the CryptoBox; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#

__revision__ = "$Id$"


## necessary: otherwise CryptoBoxRootActions.py will refuse to execute this script
PLUGIN_TYPE = "cryptobox"

IFCONFIG_BIN = "/sbin/ifconfig"
ROUTE_BIN = "/sbin/route"
DHCLIENT_BIN = "/sbin/dhclient"

import subprocess
import re
import sys

def __changeIP(interface, ipaddress, netmask="0"):
    __check_address(ipaddress)
    if netmask == "0":
        ## change the IP only
        proc = subprocess.Popen(
            shell = False,
            args = [IFCONFIG_BIN, interface, ipaddress])
        proc.wait()
    else:
        ## someone wants to change the netmask too
        __check_address(netmask)
        proc = subprocess.Popen(
            shell = False,
            args = [IFCONFIG_BIN, interface, ipaddress, "netmask", netmask])
        proc.wait()
    return proc.returncode == 0


def __changeGW(old_gw, new_gw):
    __check_address(old_gw)
    __check_address(new_gw)
    if old_gw != "0.0.0.0":
        ## assume that a default route exists and delete it
        proc = subprocess.Popen(
            shell = False,
            args = [ROUTE_BIN, "del", "default", "gw", old_gw])
        proc.wait()
        ## ignore errors
    proc = subprocess.Popen(
        shell = False,
        args = [ROUTE_BIN, "add", "default", "gw", new_gw])
    proc.wait()
    return proc.returncode == 0


def __check_address(address):
    """Check for correct numbers in given address
    """
    match = re.search(r'^(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})$', address)
    ## did we match? If yes, then: are there wrong values inside?
    if not match or [e for e in match.groups() if int(e) > 255]:
        sys.stderr.write("%s: illegal argument (%s)\n" % (self_bin, address))
        sys.exit(1)
    return

def __use_DHCP(interface):
    """Recieve network settings via dhcp
    """
    proc = subprocess.Popen(
        shell = False,
        args = [DHCLIENT_BIN, interface])
    proc.wait()


if __name__ == "__main__":
    args = sys.argv[1:]

    self_bin = sys.argv[0]
    
    if len(args) == 0:
        sys.stderr.write("%s: no argument supplied\n" % self_bin)
        sys.exit(1)
    
    try:
        if args[0] == "change_ip":
            if len(args) != 4: raise "InvalidArgNum"
            result = __changeIP(args[1], args[2], args[3])
        elif args[0] == "change_gw":
            if len(args) != 3: raise "InvalidArgNum"
            result = __changeGW(args[1], args[2])
        elif args[0] == "use_dhcp":
            if len(args) != 2: raise "InvalidArgNum"
            result = __use_DHCP(args[1])
        else:
            sys.stderr.write("%s: invalid action (%s)\n" % (self_bin, args[0]))
            sys.exit(1)
        if result:
            sys.exit(0)
        else:
            sys.exit(1)
    except "InvalidArgNum":
        sys.stderr.write("%s: invalid number of arguments (%s)\n" % (self_bin, args))
        sys.exit(1)