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
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
|
#!/usr/bin/env python3
#
# Copyright (C) 2018-2020 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 os
import argparse
from sys import exit
from copy import deepcopy
from jinja2 import FileSystemLoader, Environment
from vyos.config import Config
from vyos.defaults import directories as vyos_data_dir
from vyos.hostsd_client import Client as hostsd_client
from vyos.util import wait_for_commit_lock
from vyos import ConfigError
from vyos.util import run
parser = argparse.ArgumentParser()
parser.add_argument("--dhclient", action="store_true",
help="Started from dhclient-script")
config_file = r'/etc/powerdns/recursor.conf'
default_config_data = {
'allow_from': [],
'cache_size': 10000,
'export_hosts_file': 'yes',
'listen_on': [],
'name_servers': [],
'negative_ttl': 3600,
'domains': [],
'dnssec': 'process-no-validate'
}
def get_config(arguments):
dns = deepcopy(default_config_data)
conf = Config()
base = ['service', 'dns', 'forwarding']
if arguments.dhclient:
conf.exists = conf.exists_effective
conf.return_value = conf.return_effective_value
conf.return_values = conf.return_effective_values
if not conf.exists(base):
return None
conf.set_level(base)
if conf.exists(['allow-from']):
dns['allow_from'] = conf.return_values(['allow-from'])
if conf.exists(['cache-size']):
cache_size = conf.return_value(['cache-size'])
dns['cache_size'] = cache_size
if conf.exists('negative-ttl'):
negative_ttl = conf.return_value(['negative-ttl'])
dns['negative_ttl'] = negative_ttl
if conf.exists(['domain']):
for node in conf.list_nodes(['domain']):
servers = conf.return_values(['domain', node, 'server'])
domain = {
"name": node,
"servers": bracketize_ipv6_addrs(servers)
}
dns['domains'].append(domain)
if conf.exists(['ignore-hosts-file']):
dns['export_hosts_file'] = "no"
if conf.exists(['name-server']):
name_servers = conf.return_values(['name-server'])
dns['name_servers'] = dns['name_servers'] + name_servers
if conf.exists(['system']):
conf.set_level(['system'])
system_name_servers = []
system_name_servers = conf.return_values(['name-server'])
if not system_name_servers:
print("DNS forwarding warning: No name-servers set under 'system name-server'\n")
else:
dns['name_servers'] = dns['name_servers'] + system_name_servers
conf.set_level(base)
dns['name_servers'] = bracketize_ipv6_addrs(dns['name_servers'])
if conf.exists(['listen-address']):
dns['listen_on'] = conf.return_values(['listen-address'])
if conf.exists(['dnssec']):
dns['dnssec'] = conf.return_value(['dnssec'])
# Add name servers received from DHCP
if conf.exists(['dhcp']):
interfaces = []
interfaces = conf.return_values(['dhcp'])
hc = hostsd_client()
for interface in interfaces:
dhcp_resolvers = hc.get_name_servers(f'dhcp-{interface}')
dhcpv6_resolvers = hc.get_name_servers(f'dhcpv6-{interface}')
if dhcp_resolvers:
dns['name_servers'] = dns['name_servers'] + dhcp_resolvers
if dhcpv6_resolvers:
dns['name_servers'] = dns['name_servers'] + dhcpv6_resolvers
return dns
def bracketize_ipv6_addrs(addrs):
"""Wraps each IPv6 addr in addrs in [], leaving IPv4 addrs untouched."""
return ['[{0}]'.format(a) if a.count(':') > 1 else a for a in addrs]
def verify(dns):
# bail out early - looks like removal from running config
if dns is None:
return None
if not dns['listen_on']:
raise ConfigError(
"Error: DNS forwarding requires either a listen-address (preferred) or a listen-on option")
if not dns['allow_from']:
raise ConfigError(
"Error: DNS forwarding requires an allow-from network")
if dns['domains']:
for domain in dns['domains']:
if not domain['servers']:
raise ConfigError(
'Error: No server configured for domain {0}'.format(domain['name']))
return None
def generate(dns):
# bail out early - looks like removal from running config
if dns is None:
return None
# Prepare Jinja2 template loader from files
tmpl_path = os.path.join(vyos_data_dir['data'], 'templates', 'dns-forwarding')
fs_loader = FileSystemLoader(tmpl_path)
env = Environment(loader=fs_loader, trim_blocks=True)
tmpl = env.get_template('recursor.conf.tmpl')
config_text = tmpl.render(dns)
with open(config_file, 'w') as f:
f.write(config_text)
return None
def apply(dns):
if dns is None:
# DNS forwarding is removed in the commit
run("systemctl stop pdns-recursor")
if os.path.isfile(config_file):
os.unlink(config_file)
else:
run("systemctl restart pdns-recursor")
if __name__ == '__main__':
args = parser.parse_args()
if args.dhclient:
# There's a big chance it was triggered by a commit still in progress
# so we need to wait until the new values are in the running config
wait_for_commit_lock()
try:
c = get_config(args)
verify(c)
generate(c)
apply(c)
except ConfigError as e:
print(e)
exit(1)
|
