core-admin/qvm-tools/qubes-dom0-network-via-netvm

#!/usr/bin/python2
#
# The Qubes OS Project, http://www.qubes-os.org
#
# Copyright (C) 2010  Rafal Wojtczuk <rafal@invisiblethingslab.com>
#
# This program 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.
#
# This program 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 this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
#
#

from qubes.qubes import QubesVmCollection
import os.path
import os
import sys

qvm_collection = None

def get_netvm():
    global qvm_collection
    qvm_collection = QubesVmCollection()
    qvm_collection.lock_db_for_reading()
    qvm_collection.load()
    qvm_collection.unlock_db()
    netvm = qvm_collection.get_default_netvm()
    while netvm.netvm is not None:
        netvm = netvm.netvm
    if netvm is None or netvm.name == 'dom0':
        print >> sys.stderr, 'There seems to be no dedicated default netvm, aborting.'
        sys.exit(1)
    return netvm

def vif_eth0_exists():
    if not os.path.islink('/sys/class/net/eth0'):
        return False
    if not os.path.isdir('/sys/devices/vif-0/net/eth0'):
        print >> sys.stderr, 'There is a dedicated netvm, but device eth0 is present'
        print >> sys.stderr, 'and it is not a Xen interface. Refusing to continue.'
        sys.exit(1)
    return True

def bringup_eth0(netvm):
    resolv_conf = open('/etc/resolv.conf', "w")
    resolv_conf.write('nameserver ' + netvm.gateway + '\n')
    resolv_conf.write('nameserver ' + netvm.secondary_dns + '\n')
    resolv_conf.close()
    return os.system('ip link set eth0 up && ip addr add 10.137.0.2/32 dev eth0 && ' +
            'ip route add 10.137.0.1 dev eth0 && ip route add via 10.137.0.1') == 0

def netup():
    netvm = get_netvm()
    if os.path.isfile('/var/lock/subsys/NetworkManager'):
        os.system('/etc/init.d/NetworkManager stop')
    if not vif_eth0_exists():
        cmd = 'modprobe xen-netfront'
        if os.system(cmd) != 0:
            print >> sys.stderr, 'Error creating network device'
            sys.exit(1)
        qvm_collection[0].attach_network(verbose=True, netvm=netvm, wait=True)
    if not bringup_eth0(netvm):
        sys.exit(1)

def netdown():
    netvm = get_netvm()
    if not vif_eth0_exists():
        print >> sys.stderr, 'There is no eth0 that is a Xen vif device, aborting.'
        sys.exit(1)
    resolv_conf = open('/etc/resolv.conf', "w")
    resolv_conf.close()
    os.system('ip link set eth0 down')
    os.system('xl network-detach 0 0')

def usage():
    print >> sys.stderr, 'Usage: {0} [up|down]'.format(sys.argv[0])
    sys.exit(1)

def main():
    if len(sys.argv) != 2:
        usage()
    if os.getuid() != 0:
        print >> sys.stderr, 'This script must be run as root'
        sys.exit(1)
    if sys.argv[1] == 'up':
        netup()
        sys.exit(0)
    if sys.argv[1] == 'down':
        netdown()
        sys.exit(0)
    usage()

main()