#!/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 . import os import ipaddress from sys import exit from copy import deepcopy from vyos.config import Config from vyos.template import render from vyos.util import call from vyos.validate import is_subnet_connected, is_ipv6 from vyos import ConfigError from vyos import airbag airbag.enable() config_file = r'/run/dhcp-server/dhcpdv6.conf' default_config_data = { 'preference': '', 'disabled': False, 'shared_network': [] } def get_config(): dhcpv6 = deepcopy(default_config_data) conf = Config() base = ['service', 'dhcpv6-server'] if not conf.exists(base): return None else: conf.set_level(base) # Check for global disable of DHCPv6 service if conf.exists(['disable']): dhcpv6['disabled'] = True return dhcpv6 # Preference of this DHCPv6 server compared with others if conf.exists(['preference']): dhcpv6['preference'] = conf.return_value(['preference']) # check for multiple, shared networks served with DHCPv6 addresses if conf.exists(['shared-network-name']): for network in conf.list_nodes(['shared-network-name']): conf.set_level(base + ['shared-network-name', network]) config = { 'name': network, 'disabled': False, 'subnet': [] } # If disabled, the shared-network configuration becomes inactive if conf.exists(['disable']): config['disabled'] = True # check for multiple subnet configurations in a shared network if conf.exists(['subnet']): for net in conf.list_nodes(['subnet']): conf.set_level(base + ['shared-network-name', network, 'subnet', net]) subnet = { 'network': net, 'range6_prefix': [], 'range6': [], 'default_router': '', 'dns_server': [], 'domain_name': '', 'domain_search': [], 'lease_def': '', 'lease_min': '', 'lease_max': '', 'nis_domain': '', 'nis_server': [], 'nisp_domain': '', 'nisp_server': [], 'prefix_delegation': [], 'sip_address': [], 'sip_hostname': [], 'sntp_server': [], 'static_mapping': [] } # For any subnet on which addresses will be assigned dynamically, there must be at # least one address range statement. The range statement gives the lowest and highest # IP addresses in a range. All IP addresses in the range should be in the subnet in # which the range statement is declared. if conf.exists(['address-range', 'prefix']): for prefix in conf.list_nodes(['address-range', 'prefix']): range = { 'prefix': prefix, 'temporary': False } # Address range will be used for temporary addresses if conf.exists(['address-range' 'prefix', prefix, 'temporary']): range['temporary'] = True # Append to subnet temporary range6 list subnet['range6_prefix'].append(range) if conf.exists(['address-range', 'start']): for range in conf.list_nodes(['address-range', 'start']): range = { 'start': range, 'stop': conf.return_value(['address-range', 'start', range, 'stop']) } # Append to subnet range6 list subnet['range6'].append(range) # The domain-search option specifies a 'search list' of Domain Names to be used # by the client to locate not-fully-qualified domain names. if conf.exists(['domain-search']): subnet['domain_search'] = conf.return_values(['domain-search']) # IPv6 address valid lifetime # (at the end the address is no longer usable by the client) # (set to 30 days, the usual IPv6 default) if conf.exists(['lease-time', 'default']): subnet['lease_def'] = conf.return_value(['lease-time', 'default']) # Time should be the maximum length in seconds that will be assigned to a lease. # The only exception to this is that Dynamic BOOTP lease lengths, which are not # specified by the client, are not limited by this maximum. if conf.exists(['lease-time', 'maximum']): subnet['lease_max'] = conf.return_value(['lease-time', 'maximum']) # Time should be the minimum length in seconds that will be assigned to a lease if conf.exists(['lease-time', 'minimum']): subnet['lease_min'] = conf.return_value(['lease-time', 'minimum']) # Specifies a list of Domain Name System name servers available to the client. # Servers should be listed in order of preference. if conf.exists(['name-server']): subnet['dns_server'] = conf.return_values(['name-server']) # Ancient NIS (Network Information Service) domain name if conf.exists(['nis-domain']): subnet['nis_domain'] = conf.return_value(['nis-domain']) # Ancient NIS (Network Information Service) servers if conf.exists(['nis-server']): subnet['nis_server'] = conf.return_values(['nis-server']) # Ancient NIS+ (Network Information Service) domain name if conf.exists(['nisplus-domain']): subnet['nisp_domain'] = conf.return_value(['nisplus-domain']) # Ancient NIS+ (Network Information Service) servers if conf.exists(['nisplus-server']): subnet['nisp_server'] = conf.return_values(['nisplus-server']) # Local SIP server that is to be used for all outbound SIP requests - IPv6 address if conf.exists(['sip-server']): for value in conf.return_values(['sip-server']): if is_ipv6(value): subnet['sip_address'].append(value) else: subnet['sip_hostname'].append(value) # List of local SNTP servers available for the client to synchronize their clocks if conf.exists(['sntp-server']): subnet['sntp_server'] = conf.return_values(['sntp-server']) # Prefix Delegation (RFC 3633) if conf.exists(['prefix-delegation', 'start']): for address in conf.list_nodes(['prefix-delegation', 'start']): conf.set_level(base + ['shared-network-name', network, 'subnet', net, 'prefix-delegation', 'start', address]) prefix = { 'start' : address, 'stop' : '', 'length' : '' } if conf.exists(['prefix-length']): prefix['length'] = conf.return_value(['prefix-length']) if conf.exists(['stop']): prefix['stop'] = conf.return_value(['stop']) subnet['prefix_delegation'].append(prefix) # # Static DHCP v6 leases # conf.set_level(base + ['shared-network-name', network, 'subnet', net]) if conf.exists(['static-mapping']): for mapping in conf.list_nodes(['static-mapping']): conf.set_level(base + ['shared-network-name', network, 'subnet', net, 'static-mapping', mapping]) mapping = { 'name': mapping, 'disabled': False, 'ipv6_address': '', 'client_identifier': '', } # This static lease is disabled if conf.exists(['disable']): mapping['disabled'] = True # IPv6 address used for this DHCP client if conf.exists(['ipv6-address']): mapping['ipv6_address'] = conf.return_value(['ipv6-address']) # This option specifies the client’s DUID identifier. DUIDs are similar but different from DHCPv4 client identifiers if conf.exists(['identifier']): mapping['client_identifier'] = conf.return_value(['identifier']) # append static mapping configuration tu subnet list subnet['static_mapping'].append(mapping) # append subnet configuration to shared network subnet list config['subnet'].append(subnet) # append shared network configuration to config dictionary dhcpv6['shared_network'].append(config) # If all shared-networks are disabled, there's nothing to do. if all(net['disabled'] for net in dhcpv6['shared_network']): return None return dhcpv6 def verify(dhcpv6): if not dhcpv6 or dhcpv6['disabled']: return None # If DHCP is enabled we need one share-network if len(dhcpv6['shared_network']) == 0: raise ConfigError('No DHCPv6 shared networks configured.\n' \ 'At least one DHCPv6 shared network must be configured.') # Inspect shared-network/subnet subnets = [] listen_ok = False for network in dhcpv6['shared_network']: # A shared-network requires a subnet definition if len(network['subnet']) == 0: raise ConfigError('No DHCPv6 lease subnets configured for {0}. At least one\n' \ 'lease subnet must be configured for each shared network.'.format(network['name'])) range6_start = [] range6_stop = [] for subnet in network['subnet']: # Ususal range declaration with a start and stop address for range6 in subnet['range6']: # shorten names start = range6['start'] stop = range6['stop'] # DHCPv6 stop address is required if start and not stop: raise ConfigError('DHCPv6 range stop address for start {0} is not defined!'.format(start)) # Start address must be inside network if not ipaddress.ip_address(start) in ipaddress.ip_network(subnet['network']): raise ConfigError('DHCPv6 range start address {0} is not in subnet {1}\n' \ 'specified for shared network {2}!'.format(start, subnet['network'], network['name'])) # Stop address must be inside network if not ipaddress.ip_address(stop) in ipaddress.ip_network(subnet['network']): raise ConfigError('DHCPv6 range stop address {0} is not in subnet {1}\n' \ 'specified for shared network {2}!'.format(stop, subnet['network'], network['name'])) # Stop address must be greater or equal to start address if not ipaddress.ip_address(stop) >= ipaddress.ip_address(start): raise ConfigError('DHCPv6 range stop address {0} must be greater or equal\n' \ 'to the range start address {1}!'.format(stop, 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('Conflicting DHCPv6 lease range:\n' \ 'Pool start address {0} defined multipe times!'.format(start)) else: 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('Conflicting DHCPv6 lease range:\n' \ 'Pool stop address {0} defined multipe times!'.format(stop)) else: range6_stop.append(stop) # Prefix delegation sanity checks for prefix in subnet['prefix_delegation']: if not prefix['stop']: raise ConfigError('Stop address of delegated IPv6 prefix range must be configured') if not prefix['length']: raise ConfigError('Length of delegated IPv6 prefix must be configured') # We also have prefixes that require checking for prefix in subnet['range6_prefix']: # If configured prefix does not match our subnet, we have to check that it's inside if ipaddress.ip_network(prefix['prefix']) != ipaddress.ip_network(subnet['network']): # Configured prefixes must be inside our network if not ipaddress.ip_network(prefix['prefix']) in ipaddress.ip_network(subnet['network']): raise ConfigError('DHCPv6 prefix {0} is not in subnet {1}\n' \ 'specified for shared network {2}!'.format(prefix['prefix'], subnet['network'], network['name'])) # Static mappings don't require anything (but check if IP is in subnet if it's set) for mapping in subnet['static_mapping']: if mapping['ipv6_address']: # Static address must be in subnet if not ipaddress.ip_address(mapping['ipv6_address']) in ipaddress.ip_network(subnet['network']): raise ConfigError('DHCPv6 static mapping IPv6 address {0} for static mapping {1}\n' \ 'in shared network {2} is outside subnet {3}!' \ .format(mapping['ipv6_address'], mapping['name'], network['name'], subnet['network'])) # Subnets must be unique if subnet['network'] in subnets: raise ConfigError('DHCPv6 subnets must be unique! Subnet {0} defined multiple times!'.format(subnet['network'])) else: subnets.append(subnet['network']) # 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 not network['disabled']: if is_subnet_connected(subnet['network']): 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 = ipaddress.ip_network(subnet['network']) for n in subnets: net2 = ipaddress.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): if not dhcpv6 or dhcpv6['disabled']: return None render(config_file, 'dhcpv6-server/dhcpdv6.conf.tmpl', dhcpv6) return None def apply(dhcpv6): if not dhcpv6 or dhcpv6['disabled']: # DHCP server is removed in the commit call('systemctl stop isc-dhcp-server6.service') if os.path.exists(config_file): os.unlink(config_file) else: 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)