#!/usr/bin/env python3 # # Copyright (C) 2018-2022 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, 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 then 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 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: '\ 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}" '\ 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}"!') if 'vendor_option' in subnet_config: if len(dict_search('vendor_option.cisco.tftp_server', subnet_config)) > 2: raise ConfigError(f'No more then 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)