# Copyright (C) 2009-2010 Canonical Ltd.

# Copyright (C) 2012 Hewlett-Packard Development Company, L.P.

#

# Author: Scott Moser <scott.moser@canonical.com>

# Author: Juerg Haefliger <juerg.haefliger@hp.com>

#

# This file is part of cloud-init. See LICENSE file for license information.

"""

Disable EC2 Metadata

--------------------

**Summary:** disable aws ec2 metadata

This module can disable the ec2 datasource by rejecting the route to

``169.254.169.254``, the usual route to the datasource. This module is disabled

by default.

**Internal name:** ``cc_disable_ec2_metadata``

**Module frequency:** per always

**Supported distros:** all

**Config keys**::

    disable_ec2_metadata: <true/false>

"""

from cloudinit import subp

from cloudinit import util

from cloudinit.settings import PER_ALWAYS

frequency = PER_ALWAYS

REJECT_CMD_IF = ['route', 'add', '-host', '169.254.169.254', 'reject']

REJECT_CMD_IP = ['ip', 'route', 'add', 'prohibit', '169.254.169.254']

def handle(name, cfg, _cloud, log, _args):

    disabled = util.get_cfg_option_bool(cfg, "disable_ec2_metadata", False)

    if disabled:

        reject_cmd = None

        if subp.which('ip'):

            reject_cmd = REJECT_CMD_IP

        elif subp.which('ifconfig'):

            reject_cmd = REJECT_CMD_IF

        else:

            log.error(('Neither "route" nor "ip" command found, unable to '

                       'manipulate routing table'))

            return

        subp.subp(reject_cmd, capture=False)

    else:

        log.debug(("Skipping module named %s,"

                   " disabling the ec2 route not enabled"), name)

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