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#!/usr/bin/env python3
#
# Copyright (C) 2018-2024 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.utils.process import call
from vyos.utils.dict import dict_search
from vyos.utils.network 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,
no_tag_node_value_mangle=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 '\
'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 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 than or equal ' \
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: '\
f'Pool start address "{start}" defined multiple 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: '\
f'Pool stop address "{stop}" defined multiple 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(f'Start address of delegated IPv6 prefix range "{prefix}" '\
f'must be configured!')
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}" '\
f'must be configured!')
start_addr = prefix
stop_addr = prefix_config['stop']
if ip_address(stop_addr) <= ip_address(start_addr):
raise ConfigError(f'Stop address of delegated IPv6 prefix range "{prefix}" '\
f'must be greater than start address!')
if 'prefix_length' not in prefix_config:
raise ConfigError(f'Length of delegated IPv6 prefix '\
f'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}"!')
if 'vendor_option' in subnet_config:
if len(dict_search('vendor_option.cisco.tftp_server', subnet_config)) > 2:
raise ConfigError(f'No more than two Cisco tftp-servers should be defined for 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 '\
'this machine. At least one subnet6 must be connected such that '\
'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.j2', dhcpv6)
return None
def apply(dhcpv6):
# bail out early - looks like removal from running config
service_name = 'isc-dhcp-server6.service'
if not dhcpv6 or 'disable' in dhcpv6:
# DHCP server is removed in the commit
call(f'systemctl stop {service_name}')
if os.path.exists(config_file):
os.unlink(config_file)
return None
call(f'systemctl restart {service_name}')
return None
if __name__ == '__main__':
try:
c = get_config()
verify(c)
generate(c)
apply(c)
except ConfigError as e:
print(e)
exit(1)
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