ansible/system/iptables.py

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#!/usr/bin/python
# -*- coding: utf-8 -*-
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#
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# (c) 2015, Linus Unnebäck <linus@folkdatorn.se>
#
# This file is part of Ansible
#
# This module 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 3 of the License, or
# (at your option) any later version.
#
# This software 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 software. If not, see <http://www.gnu.org/licenses/>.
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BINS = dict(
ipv4='iptables',
ipv6='ip6tables',
)
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DOCUMENTATION = '''
---
module: iptables
short_description: Modify the systems iptables
requirements: []
version_added: "2.0"
author: Linus Unnebäck (@LinusU) <linus@folkdatorn.se>
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description:
- Iptables is used to set up, maintain, and inspect the tables of IP packet
filter rules in the Linux kernel. This module does not handle the saving
and/or loading of rules, but rather only manipulates the current rules
that are present in memory. This is the same as the behaviour of the
"iptables" and "ip6tables" command which this module uses internally.
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notes:
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- This module just deals with individual rules. If you need advanced
chaining of rules the recommended way is to template the iptables restore
file.
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options:
table:
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description:
- This option specifies the packet matching table which the command
should operate on. If the kernel is configured with automatic module
loading, an attempt will be made to load the appropriate module for
that table if it is not already there.
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required: false
default: filter
choices: [ "filter", "nat", "mangle", "raw", "security" ]
state:
description:
- Whether the rule should be absent or present.
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required: false
default: present
choices: [ "present", "absent" ]
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ip_version:
description:
- Which version of the IP protocol this rule should apply to.
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required: false
default: ipv4
choices: [ "ipv4", "ipv6" ]
chain:
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description:
- "Chain to operate on. This option can either be the name of a user
defined chain or any of the builtin chains: 'INPUT', 'FORWARD',
'OUTPUT', 'PREROUTING', 'POSTROUTING', 'SECMARK', 'CONNSECMARK'"
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required: true
protocol:
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description:
- The protocol of the rule or of the packet to check. The specified
protocol can be one of tcp, udp, udplite, icmp, esp, ah, sctp or the
special keyword "all", or it can be a numeric value, representing one
of these protocols or a different one. A protocol name from
/etc/protocols is also allowed. A "!" argument before the protocol
inverts the test. The number zero is equivalent to all. "all" will
match with all protocols and is taken as default when this option is
omitted.
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required: false
source:
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description:
- Source specification. Address can be either a network name,
a hostname, a network IP address (with /mask), or a plain IP address.
Hostnames will be resolved once only, before the rule is submitted to
the kernel. Please note that specifying any name to be resolved with
a remote query such as DNS is a really bad idea. The mask can be
either a network mask or a plain number, specifying the number of 1's
at the left side of the network mask. Thus, a mask of 24 is equivalent
to 255.255.255.0. A "!" argument before the address specification
inverts the sense of the address.Source specification. Address can be
either a network name, a hostname, a network IP address (with /mask),
or a plain IP address. Hostnames will be resolved once only, before
the rule is submitted to the kernel. Please note that specifying any
name to be resolved with a remote query such as DNS is a really bad
idea. The mask can be either a network mask or a plain number,
specifying the number of 1's at the left side of the network mask.
Thus, a mask of 24 is equivalent to 255.255.255.0. A "!" argument
before the address specification inverts the sense of the address.
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required: false
destination:
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description:
- Destination specification. Address can be either a network name,
a hostname, a network IP address (with /mask), or a plain IP address.
Hostnames will be resolved once only, before the rule is submitted to
the kernel. Please note that specifying any name to be resolved with
a remote query such as DNS is a really bad idea. The mask can be
either a network mask or a plain number, specifying the number of 1's
at the left side of the network mask. Thus, a mask of 24 is equivalent
to 255.255.255.0. A "!" argument before the address specification
inverts the sense of the address.Source specification. Address can be
either a network name, a hostname, a network IP address (with /mask),
or a plain IP address. Hostnames will be resolved once only, before
the rule is submitted to the kernel. Please note that specifying any
name to be resolved with a remote query such as DNS is a really bad
idea. The mask can be either a network mask or a plain number,
specifying the number of 1's at the left side of the network mask.
Thus, a mask of 24 is equivalent to 255.255.255.0. A "!" argument
before the address specification inverts the sense of the address.
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required: false
match:
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description:
- Specifies a match to use, that is, an extension module that tests for
a specific property. The set of matches make up the condition under
which a target is invoked. Matches are evaluated first to last if
specified as an array and work in short-circuit fashion, i.e. if one
extension yields false, evaluation will stop.
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required: false
jump:
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description:
- This specifies the target of the rule; i.e., what to do if the packet
matches it. The target can be a user-defined chain (other than the one
this rule is in), one of the special builtin targets which decide the
fate of the packet immediately, or an extension (see EXTENSIONS
below). If this option is omitted in a rule (and the goto paramater
is not used), then matching the rule will have no effect on the
packet's fate, but the counters on the rule will be incremented.
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required: false
goto:
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description:
- This specifies that the processing should continue in a user specified
chain. Unlike the jump argument return will not continue processing in
this chain but instead in the chain that called us via jump.
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required: false
in_interface:
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description:
- Name of an interface via which a packet was received (only for packets
entering the INPUT, FORWARD and PREROUTING chains). When the "!"
argument is used before the interface name, the sense is inverted. If
the interface name ends in a "+", then any interface which begins with
this name will match. If this option is omitted, any interface name
will match.
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required: false
out_interface:
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description:
- Name of an interface via which a packet is going to be sent (for
packets entering the FORWARD, OUTPUT and POSTROUTING chains). When the
"!" argument is used before the interface name, the sense is inverted.
If the interface name ends in a "+", then any interface which begins
with this name will match. If this option is omitted, any interface
name will match.
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required: false
fragment:
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description:
- This means that the rule only refers to second and further fragments
of fragmented packets. Since there is no way to tell the source or
destination ports of such a packet (or ICMP type), such a packet will
not match any rules which specify them. When the "!" argument precedes
fragment argument, the rule will only match head fragments, or
unfragmented packets.
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required: false
set_counters:
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description:
- This enables the administrator to initialize the packet and byte
counters of a rule (during INSERT, APPEND, REPLACE operations).
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required: false
source_port:
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description:
- "Source port or port range specification. This can either be a service
name or a port number. An inclusive range can also be specified, using
the format first:last. If the first port is omitted, '0' is assumed;
if the last is omitted, '65535' is assumed. If the first port is
greater than the second one they will be swapped."
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required: false
destination_port:
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description:
- "Destination port or port range specification. This can either be
a service name or a port number. An inclusive range can also be
specified, using the format first:last. If the first port is omitted,
'0' is assumed; if the last is omitted, '65535' is assumed. If the
first port is greater than the second one they will be swapped."
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required: false
to_ports:
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description:
- "This specifies a destination port or range of ports to use: without
this, the destination port is never altered. This is only valid if the
rule also specifies one of the following protocols: tcp, udp, dccp or
sctp."
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required: false
comment:
description:
- "This specifies a comment that will be added to the rule"
required: false
ctstate:
description:
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- "ctstate is a list of the connection states to match in the conntrack module.
Possible states are: 'INVALID', 'NEW', 'ESTABLISHED', 'RELATED', 'UNTRACKED', 'SNAT', 'DNAT'"
required: false
limit:
description:
- "Specifies the maximum average number of matches to allow per second. The number can specify units explicitly, using `/second', `/minute', `/hour' or `/day', or parts of them (so `5/second' is the same as `5/s')."
required: false
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'''
EXAMPLES = '''
# Block specific IP
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- iptables: chain=INPUT source=8.8.8.8 jump=DROP
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become: yes
# Forward port 80 to 8600
- iptables: table=nat chain=PREROUTING in_interface=eth0 protocol=tcp match=tcp destination_port=80 jump=REDIRECT to_ports=8600 comment="Redirect web traffic to port 8600"
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become: yes
# Allow related and established connections
- iptables: chain=INPUT ctstate=ESTABLISHED,RELATED jump=ACCEPT
become: yes
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'''
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def append_param(rule, param, flag, is_list):
if is_list:
for item in param:
append_param(rule, item, flag, False)
else:
if param is not None:
rule.extend([flag, param])
def append_comm(rule, param):
if param:
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rule.extend(['-m'])
rule.extend(['comment'])
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def append_conntrack(rule, param):
if param:
rule.extend(['-m'])
rule.extend(['state'])
def append_limit(rule, param):
if param:
rule.extend(['-m'])
rule.extend(['limit'])
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def construct_rule(params):
rule = []
append_param(rule, params['protocol'], '-p', False)
append_param(rule, params['source'], '-s', False)
append_param(rule, params['destination'], '-d', False)
append_param(rule, params['match'], '-m', True)
append_param(rule, params['jump'], '-j', False)
append_param(rule, params['goto'], '-g', False)
append_param(rule, params['in_interface'], '-i', False)
append_param(rule, params['out_interface'], '-o', False)
append_param(rule, params['fragment'], '-f', False)
append_param(rule, params['set_counters'], '-c', False)
append_param(rule, params['source_port'], '--source-port', False)
append_param(rule, params['destination_port'], '--destination-port', False)
append_param(rule, params['to_ports'], '--to-ports', False)
append_comm(rule, params['comment'])
append_param(rule, params['comment'], '--comment', False)
if params['ctstate']:
append_conntrack(rule, params['ctstate'])
append_param(rule, ','.join(params['ctstate']), '--state', False)
append_limit(rule, params['limit'])
append_param(rule, params['limit'], '--limit', False)
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return rule
def push_arguments(iptables_path, action, params):
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cmd = [iptables_path]
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cmd.extend(['-t', params['table']])
cmd.extend([action, params['chain']])
cmd.extend(construct_rule(params))
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return cmd
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def check_present(iptables_path, module, params):
cmd = push_arguments(iptables_path, '-C', params)
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rc, _, __ = module.run_command(cmd, check_rc=False)
return (rc == 0)
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def append_rule(iptables_path, module, params):
cmd = push_arguments(iptables_path, '-A', params)
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module.run_command(cmd, check_rc=True)
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def remove_rule(iptables_path, module, params):
cmd = push_arguments(iptables_path, '-D', params)
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module.run_command(cmd, check_rc=True)
def main():
module = AnsibleModule(
supports_check_mode=True,
argument_spec=dict(
table=dict(required=False, default='filter', choices=['filter', 'nat', 'mangle', 'raw', 'security']),
state=dict(required=False, default='present', choices=['present', 'absent']),
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ip_version=dict(required=False, default='ipv4', choices=['ipv4', 'ipv6']),
chain=dict(required=True, default=None, type='str'),
protocol=dict(required=False, default=None, type='str'),
source=dict(required=False, default=None, type='str'),
destination=dict(required=False, default=None, type='str'),
match=dict(required=False, default=[], type='list'),
jump=dict(required=False, default=None, type='str'),
goto=dict(required=False, default=None, type='str'),
in_interface=dict(required=False, default=None, type='str'),
out_interface=dict(required=False, default=None, type='str'),
fragment=dict(required=False, default=None, type='str'),
set_counters=dict(required=False, default=None, type='str'),
source_port=dict(required=False, default=None, type='str'),
destination_port=dict(required=False, default=None, type='str'),
to_ports=dict(required=False, default=None, type='str'),
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comment=dict(required=False, default=None, type='str'),
ctstate=dict(required=False, default=[], type='list'),
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limit=dict(required=False, default=None, type='str'),
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),
)
args = dict(
changed=False,
failed=False,
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ip_version=module.params['ip_version'],
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table=module.params['table'],
chain=module.params['chain'],
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rule=' '.join(construct_rule(module.params)),
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state=module.params['state'],
)
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ip_version = module.params['ip_version']
iptables_path = module.get_bin_path(BINS[ip_version], True)
rule_is_present = check_present(iptables_path, module, module.params)
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should_be_present = (args['state'] == 'present')
# Check if target is up to date
args['changed'] = (rule_is_present != should_be_present)
# Check only; don't modify
if module.check_mode:
module.exit_json(changed=args['changed'])
# Target is already up to date
if args['changed'] == False:
module.exit_json(**args)
if should_be_present:
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append_rule(iptables_path, module, module.params)
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else:
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remove_rule(iptables_path, module, module.params)
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module.exit_json(**args)
# import module snippets
from ansible.module_utils.basic import *
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if __name__ == '__main__':
main()