summaryrefslogtreecommitdiff
path: root/src/conf_mode/dhcpv6_server.py
blob: e6a2e44867b36396f682bacab726569a45ba885c (plain)
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
#!/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

from ipaddress import ip_address
from ipaddress import ip_network
from sys import exit

from vyos.config import Config
from vyos.template import render
from vyos.template import is_ipv6
from vyos.util import call
from vyos.util import dict_search
from vyos.validate import is_subnet_connected
from vyos import ConfigError
from vyos import airbag
airbag.enable()

config_file = '/run/dhcp-server/dhcpdv6.conf'

def get_config(config=None):
    if config:
        conf = config
    else:
        conf = Config()
    base = ['service', 'dhcpv6-server']
    if not conf.exists(base):
        return None

    dhcpv6 = conf.get_config_dict(base, key_mangling=('-', '_'), get_first_key=True)
    return dhcpv6

def verify(dhcpv6):
    # bail out early - looks like removal from running config
    if not dhcpv6 or 'disable' in dhcpv6:
        return None

    # If DHCP is enabled we need one share-network
    if 'shared_network_name' not in dhcpv6:
        raise ConfigError('No DHCPv6 shared networks configured. At least\n' \
                          'one DHCPv6 shared network must be configured.')

    # Inspect shared-network/subnet
    subnets = []
    listen_ok = False
    for network, network_config in dhcpv6['shared_network_name'].items():
        # A shared-network requires a subnet definition
        if 'subnet' not in network_config:
            raise ConfigError(f'No DHCPv6 lease subnets configured for "{network}". At least one\n' \
                              'lease subnet must be configured for each shared network!')

        for subnet, subnet_config in network_config['subnet'].items():
            if 'address_range' in subnet_config:
                if 'start' in subnet_config['address_range']:
                    range6_start = []
                    range6_stop = []
                    for start, start_config in subnet_config['address_range']['start'].items():
                        if 'stop' not in start_config:
                            raise ConfigError(f'address-range stop address for start "{start}" is not defined!')
                        stop = start_config['stop']

                        # Start address must be inside network
                        if not ip_address(start) in ip_network(subnet):
                            raise ConfigError(f'address-range start address "{start}" is not in subnet "{subnet}"!')

                        # Stop address must be inside network
                        if not ip_address(stop) in ip_network(subnet):
                             raise ConfigError(f'address-range stop address "{stop}" is not in subnet "{subnet}"!')

                        # Stop address must be greater or equal to start address
                        if not ip_address(stop) >= ip_address(start):
                            raise ConfigError(f'address-range stop address "{stop}" must be greater or equal\n' \
                                              f'to the range start address "{start}"!')

                        # DHCPv6 range start address must be unique - two ranges can't
                        # start with the same address - makes no sense
                        if start in range6_start:
                            raise ConfigError(f'Conflicting DHCPv6 lease range:\n' \
                                              f'Pool start address "{start}" defined multipe times!')
                        range6_start.append(start)

                        # DHCPv6 range stop address must be unique - two ranges can't
                        # end with the same address - makes no sense
                        if stop in range6_stop:
                            raise ConfigError(f'Conflicting DHCPv6 lease range:\n' \
                                              f'Pool stop address "{stop}" defined multipe times!')
                        range6_stop.append(stop)

                if 'prefix' in subnet_config:
                    for prefix in subnet_config['prefix']:
                        if ip_network(prefix) not in ip_network(subnet):
                            raise ConfigError(f'address-range prefix "{prefix}" is not in subnet "{subnet}""')

            # Prefix delegation sanity checks
            if 'prefix_delegation' in subnet_config:
                if 'start' not in subnet_config['prefix_delegation']:
                    raise ConfigError('prefix-delegation start address not defined!')

                for prefix, prefix_config in subnet_config['prefix_delegation']['start'].items():
                    if 'stop' not in prefix_config:
                        raise ConfigError(f'Stop address of delegated IPv6 prefix range "{prefix}"\n'
                                          f'must be configured')

                    if 'prefix_length' not in prefix_config:
                        raise ConfigError('Length of delegated IPv6 prefix must be configured')

            # Static mappings don't require anything (but check if IP is in subnet if it's set)
            if 'static_mapping' in subnet_config:
                for mapping, mapping_config in subnet_config['static_mapping'].items():
                    if 'ipv6_address' in mapping_config:
                        # Static address must be in subnet
                        if ip_address(mapping_config['ipv6_address']) not in ip_network(subnet):
                            raise ConfigError(f'static-mapping address for mapping "{mapping}" is not in subnet "{subnet}"!')

            # Subnets must be unique
            if subnet in subnets:
                raise ConfigError(f'DHCPv6 subnets must be unique! Subnet {subnet} defined multiple times!')
            subnets.append(subnet)

        # DHCPv6 requires at least one configured address range or one static mapping
        # (FIXME: is not actually checked right now?)

        # There must be one subnet connected to a listen interface if network is not disabled.
        if 'disable' not in network_config:
            if is_subnet_connected(subnet):
                listen_ok = True

            # DHCPv6 subnet must not overlap. ISC DHCP also complains about overlapping
            # subnets: "Warning: subnet 2001:db8::/32 overlaps subnet 2001:db8:1::/32"
            net = ip_network(subnet)
            for n in subnets:
                net2 = ip_network(n)
                if (net != net2):
                    if net.overlaps(net2):
                        raise ConfigError('DHCPv6 conflicting subnet ranges: {0} overlaps {1}'.format(net, net2))

    if not listen_ok:
        raise ConfigError('None of the DHCPv6 subnets are connected to a subnet6 on\n' \
                          'this machine. At least one subnet6 must be connected such that\n' \
                          'DHCPv6 listens on an interface!')


    return None

def generate(dhcpv6):
    # bail out early - looks like removal from running config
    if not dhcpv6 or 'disable' in dhcpv6:
        return None

    render(config_file, 'dhcp-server/dhcpdv6.conf.tmpl', dhcpv6)
    return None

def apply(dhcpv6):
    # bail out early - looks like removal from running config
    if not dhcpv6 or 'disable' in dhcpv6:
        # DHCP server is removed in the commit
        call('systemctl stop isc-dhcp-server6.service')
        if os.path.exists(config_file):
            os.unlink(config_file)

        return None

    call('systemctl restart isc-dhcp-server6.service')
    return None

if __name__ == '__main__':
    try:
        c = get_config()
        verify(c)
        generate(c)
        apply(c)
    except ConfigError as e:
        print(e)
        exit(1)