1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
|
#!/usr/bin/env python3
#
# Copyright (C) 2020 VyOS maintainers and contributors
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 or later as
# published by the Free Software Foundation.
#
# 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, see <http://www.gnu.org/licenses/>.
import jmespath
import json
import os
from sys import exit
from netifaces import interfaces
from vyos.config import Config
from vyos.configdict import dict_merge
from vyos.template import render
from vyos.util import cmd
from vyos.util import check_kmod
from vyos.util import dict_search
from vyos.template import is_ipv6
from vyos.xml import defaults
from vyos import ConfigError
import platform
from vyos import airbag
airbag.enable()
k_mod = ['nft_nat', 'nft_chain_nat']
iptables_nat_config = '/tmp/vyos-nat66-rules.nft'
ndppd_config = '/run/ndppd/ndppd.conf'
def get_handler(json, chain, target):
""" Get nftable rule handler number of given chain/target combination.
Handler is required when adding NAT66/Conntrack helper targets """
for x in json:
if x['chain'] != chain:
continue
if x['target'] != target:
continue
return x['handle']
return None
def get_config(config=None):
if config:
conf = config
else:
conf = Config()
base = ['nat66']
nat = conf.get_config_dict(base, key_mangling=('-', '_'), get_first_key=True)
# T2665: we must add the tagNode defaults individually until this is
# moved to the base class
for direction in ['source', 'destination']:
if direction in nat:
default_values = defaults(base + [direction, 'rule'])
if 'rule' in nat[direction]:
for rule in nat[direction]['rule']:
nat[direction]['rule'][rule] = dict_merge(default_values,
nat[direction]['rule'][rule])
# read in current nftable (once) for further processing
tmp = cmd('nft -j list table ip6 raw')
nftable_json = json.loads(tmp)
# condense the full JSON table into a list with only relevand informations
pattern = 'nftables[?rule].rule[?expr[].jump].{chain: chain, handle: handle, target: expr[].jump.target | [0]}'
condensed_json = jmespath.search(pattern, nftable_json)
if not conf.exists(base):
nat['helper_functions'] = 'remove'
nat['pre_ct_conntrack'] = get_handler(condensed_json, 'PREROUTING', 'NAT_CONNTRACK')
nat['out_ct_conntrack'] = get_handler(condensed_json, 'OUTPUT','NAT_CONNTRACK')
nat['deleted'] = ''
return nat
# check if NAT66 connection tracking helpers need to be set up - this has to
# be done only once
if not get_handler(condensed_json, 'PREROUTING', 'NAT_CONNTRACK'):
nat['helper_functions'] = 'add'
# Retrieve current table handler positions
nat['pre_ct_conntrack'] = get_handler(condensed_json, 'PREROUTING', 'VYATTA_CT_PREROUTING_HOOK')
nat['out_ct_conntrack'] = get_handler(condensed_json, 'OUTPUT','VYATTA_CT_OUTPUT_HOOK')
else:
nat['helper_functions'] = 'has'
return nat
def verify(nat):
if not nat or 'deleted' in nat:
# no need to verify the CLI as NAT66 is going to be deactivated
return None
if 'helper_functions' in nat and nat['helper_functions'] != 'has':
if not (nat['pre_ct_conntrack'] or nat['out_ct_conntrack']):
raise Exception('could not determine nftable ruleset handlers')
if dict_search('source.rule', nat):
for rule, config in dict_search('source.rule', nat).items():
err_msg = f'Source NAT66 configuration error in rule {rule}:'
if 'outbound_interface' not in config:
raise ConfigError(f'{err_msg}\n' \
'outbound-interface not specified')
else:
if config['outbound_interface'] not in interfaces():
print(f'WARNING: rule "{rule}" interface "{config["outbound_interface"]}" does not exist on this system')
prefix = dict_search('translation.prefix', config)
if prefix != None:
if not is_ipv6(prefix):
raise ConfigError(f'Warning: IPv6 prefix {prefix} is not a valid address prefix')
prefix = dict_search('source.prefix', config)
if prefix != None:
if not is_ipv6(prefix):
raise ConfigError(f'{err_msg} source-prefix not specified')
if dict_search('destination.rule', nat):
for rule, config in dict_search('destination.rule', nat).items():
err_msg = f'Destination NAT66 configuration error in rule {rule}:'
if 'inbound_interface' not in config:
raise ConfigError(f'{err_msg}\n' \
'inbound-interface not specified')
else:
if config['inbound_interface'] not in 'any' and config['inbound_interface'] not in interfaces():
print(f'WARNING: rule "{rule}" interface "{config["inbound_interface"]}" does not exist on this system')
return None
def generate(nat):
render(iptables_nat_config, 'firewall/nftables-nat66.tmpl', nat, permission=0o755)
render(ndppd_config, 'proxy-ndp/ndppd.conf.tmpl', nat, permission=0o755)
return None
def apply(nat):
if not nat:
return None
cmd(f'{iptables_nat_config}')
if 'deleted' in nat or not dict_search('source.rule', nat):
cmd('systemctl stop ndppd')
if os.path.isfile(ndppd_config):
os.unlink(ndppd_config)
else:
cmd('systemctl restart ndppd')
if os.path.isfile(iptables_nat_config):
os.unlink(iptables_nat_config)
return None
if __name__ == '__main__':
try:
check_kmod(k_mod)
c = get_config()
verify(c)
generate(c)
apply(c)
except ConfigError as e:
print(e)
exit(1)
|
