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-rwxr-xr-xsrc/conf_mode/service_dhcp-server.py328
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diff --git a/src/conf_mode/service_dhcp-server.py b/src/conf_mode/service_dhcp-server.py
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+#!/usr/bin/env python3
+#
+# Copyright (C) 2018-2023 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 netaddr import IPAddress
+from netaddr import IPRange
+from sys import exit
+
+from vyos.config import Config
+from vyos.template import render
+from vyos.utils.dict import dict_search
+from vyos.utils.process import call
+from vyos.utils.process import run
+from vyos.utils.network import is_subnet_connected
+from vyos.utils.network import is_addr_assigned
+from vyos import ConfigError
+from vyos import airbag
+airbag.enable()
+
+config_file = '/run/dhcp-server/dhcpd.conf'
+systemd_override = r'/run/systemd/system/isc-dhcp-server.service.d/10-override.conf'
+
+def dhcp_slice_range(exclude_list, range_dict):
+ """
+ This function is intended to slice a DHCP range. What does it mean?
+
+ Lets assume we have a DHCP range from '192.0.2.1' to '192.0.2.100'
+ but want to exclude address '192.0.2.74' and '192.0.2.75'. We will
+ pass an input 'range_dict' in the format:
+ {'start' : '192.0.2.1', 'stop' : '192.0.2.100' }
+ and we will receive an output list of:
+ [{'start' : '192.0.2.1' , 'stop' : '192.0.2.73' },
+ {'start' : '192.0.2.76', 'stop' : '192.0.2.100' }]
+ The resulting list can then be used in turn to build the proper dhcpd
+ configuration file.
+ """
+ output = []
+ # exclude list must be sorted for this to work
+ exclude_list = sorted(exclude_list)
+ range_start = range_dict['start']
+ range_stop = range_dict['stop']
+ range_last_exclude = ''
+
+ for e in exclude_list:
+ if (ip_address(e) >= ip_address(range_start)) and \
+ (ip_address(e) <= ip_address(range_stop)):
+ range_last_exclude = e
+
+ for e in exclude_list:
+ if (ip_address(e) >= ip_address(range_start)) and \
+ (ip_address(e) <= ip_address(range_stop)):
+
+ # Build new address range ending one address before exclude address
+ r = {
+ 'start' : range_start,
+ 'stop' : str(ip_address(e) -1)
+ }
+ # On the next run our address range will start one address after
+ # the exclude address
+ range_start = str(ip_address(e) + 1)
+
+ # on subsequent exclude addresses we can not
+ # append them to our output
+ if not (ip_address(r['start']) > ip_address(r['stop'])):
+ # Everything is fine, add range to result
+ output.append(r)
+
+ # Take care of last IP address range spanning from the last exclude
+ # address (+1) to the end of the initial configured range
+ if ip_address(e) == ip_address(range_last_exclude):
+ r = {
+ 'start': str(ip_address(e) + 1),
+ 'stop': str(range_stop)
+ }
+ if not (ip_address(r['start']) > ip_address(r['stop'])):
+ output.append(r)
+ else:
+ # if the excluded address was not part of the range, we simply return
+ # the entire ranga again
+ if not range_last_exclude:
+ if range_dict not in output:
+ output.append(range_dict)
+
+ return output
+
+def get_config(config=None):
+ if config:
+ conf = config
+ else:
+ conf = Config()
+ base = ['service', 'dhcp-server']
+ if not conf.exists(base):
+ return None
+
+ dhcp = conf.get_config_dict(base, key_mangling=('-', '_'),
+ no_tag_node_value_mangle=True,
+ get_first_key=True,
+ with_recursive_defaults=True)
+
+ if 'shared_network_name' in dhcp:
+ for network, network_config in dhcp['shared_network_name'].items():
+ if 'subnet' in network_config:
+ for subnet, subnet_config in network_config['subnet'].items():
+ # If exclude IP addresses are defined we need to slice them out of
+ # the defined ranges
+ if {'exclude', 'range'} <= set(subnet_config):
+ new_range_id = 0
+ new_range_dict = {}
+ for r, r_config in subnet_config['range'].items():
+ for slice in dhcp_slice_range(subnet_config['exclude'], r_config):
+ new_range_dict.update({new_range_id : slice})
+ new_range_id +=1
+
+ dhcp['shared_network_name'][network]['subnet'][subnet].update(
+ {'range' : new_range_dict})
+
+ return dhcp
+
+def verify(dhcp):
+ # bail out early - looks like removal from running config
+ if not dhcp or 'disable' in dhcp:
+ return None
+
+ # If DHCP is enabled we need one share-network
+ if 'shared_network_name' not in dhcp:
+ raise ConfigError('No DHCP shared networks configured.\n' \
+ 'At least one DHCP shared network must be configured.')
+
+ # Inspect shared-network/subnet
+ listen_ok = False
+ subnets = []
+ failover_ok = False
+ shared_networks = len(dhcp['shared_network_name'])
+ disabled_shared_networks = 0
+
+
+ # A shared-network requires a subnet definition
+ for network, network_config in dhcp['shared_network_name'].items():
+ if 'disable' in network_config:
+ disabled_shared_networks += 1
+
+ if 'subnet' not in network_config:
+ raise ConfigError(f'No subnets defined for {network}. At least one\n' \
+ 'lease subnet must be configured.')
+
+ for subnet, subnet_config in network_config['subnet'].items():
+ # All delivered static routes require a next-hop to be set
+ if 'static_route' in subnet_config:
+ for route, route_option in subnet_config['static_route'].items():
+ if 'next_hop' not in route_option:
+ raise ConfigError(f'DHCP static-route "{route}" requires router to be defined!')
+
+ # DHCP failover needs at least one subnet that uses it
+ if 'enable_failover' in subnet_config:
+ if 'failover' not in dhcp:
+ raise ConfigError(f'Can not enable failover for "{subnet}" in "{network}".\n' \
+ 'Failover is not configured globally!')
+ failover_ok = True
+
+ # Check if DHCP address range is inside configured subnet declaration
+ if 'range' in subnet_config:
+ networks = []
+ for range, range_config in subnet_config['range'].items():
+ if not {'start', 'stop'} <= set(range_config):
+ raise ConfigError(f'DHCP range "{range}" start and stop address must be defined!')
+
+ # Start/Stop address must be inside network
+ for key in ['start', 'stop']:
+ if ip_address(range_config[key]) not in ip_network(subnet):
+ raise ConfigError(f'DHCP range "{range}" {key} address not within shared-network "{network}, {subnet}"!')
+
+ # Stop address must be greater or equal to start address
+ if ip_address(range_config['stop']) < ip_address(range_config['start']):
+ raise ConfigError(f'DHCP range "{range}" stop address must be greater or equal\n' \
+ 'to the ranges start address!')
+
+ for network in networks:
+ start = range_config['start']
+ stop = range_config['stop']
+ if start in network:
+ raise ConfigError(f'Range "{range}" start address "{start}" already part of another range!')
+ if stop in network:
+ raise ConfigError(f'Range "{range}" stop address "{stop}" already part of another range!')
+
+ tmp = IPRange(range_config['start'], range_config['stop'])
+ networks.append(tmp)
+
+ # Exclude addresses must be in bound
+ if 'exclude' in subnet_config:
+ for exclude in subnet_config['exclude']:
+ if ip_address(exclude) not in ip_network(subnet):
+ raise ConfigError(f'Excluded IP address "{exclude}" not within shared-network "{network}, {subnet}"!')
+
+ # At least one DHCP address range or static-mapping required
+ if 'range' not in subnet_config and 'static_mapping' not in subnet_config:
+ raise ConfigError(f'No DHCP address range or active static-mapping configured\n' \
+ f'within shared-network "{network}, {subnet}"!')
+
+ if 'static_mapping' in subnet_config:
+ # Static mappings require just a MAC address (will use an IP from the dynamic pool if IP is not set)
+ for mapping, mapping_config in subnet_config['static_mapping'].items():
+ if 'ip_address' in mapping_config:
+ if ip_address(mapping_config['ip_address']) not in ip_network(subnet):
+ raise ConfigError(f'Configured static lease address for mapping "{mapping}" is\n' \
+ f'not within shared-network "{network}, {subnet}"!')
+
+ if 'mac_address' not in mapping_config:
+ raise ConfigError(f'MAC address required for static mapping "{mapping}"\n' \
+ f'within shared-network "{network}, {subnet}"!')
+
+ # There must be one subnet connected to a listen interface.
+ # This only counts if the network itself is not disabled!
+ if 'disable' not in network_config:
+ if is_subnet_connected(subnet, primary=False):
+ listen_ok = True
+
+ # Subnets must be non overlapping
+ if subnet in subnets:
+ raise ConfigError(f'Configured subnets must be unique! Subnet "{subnet}"\n'
+ 'defined multiple times!')
+ subnets.append(subnet)
+
+ # Check for overlapping subnets
+ net = ip_network(subnet)
+ for n in subnets:
+ net2 = ip_network(n)
+ if (net != net2):
+ if net.overlaps(net2):
+ raise ConfigError(f'Conflicting subnet ranges: "{net}" overlaps "{net2}"!')
+
+ # Prevent 'disable' for shared-network if only one network is configured
+ if (shared_networks - disabled_shared_networks) < 1:
+ raise ConfigError(f'At least one shared network must be active!')
+
+ if 'failover' in dhcp:
+ if not failover_ok:
+ raise ConfigError('DHCP failover must be enabled for at least one subnet!')
+
+ for key in ['name', 'remote', 'source_address', 'status']:
+ if key not in dhcp['failover']:
+ tmp = key.replace('_', '-')
+ raise ConfigError(f'DHCP failover requires "{tmp}" to be specified!')
+
+ for address in (dict_search('listen_address', dhcp) or []):
+ if is_addr_assigned(address):
+ listen_ok = True
+ # no need to probe further networks, we have one that is valid
+ continue
+ else:
+ raise ConfigError(f'listen-address "{address}" not configured on any interface')
+
+
+ if not listen_ok:
+ raise ConfigError('None of the configured subnets have an appropriate primary IP address on any\n'
+ 'broadcast interface configured, nor was there an explicit listen-address\n'
+ 'configured for serving DHCP relay packets!')
+
+ return None
+
+def generate(dhcp):
+ # bail out early - looks like removal from running config
+ if not dhcp or 'disable' in dhcp:
+ return None
+
+ # Please see: https://vyos.dev/T1129 for quoting of the raw
+ # parameters we can pass to ISC DHCPd
+ tmp_file = '/tmp/dhcpd.conf'
+ render(tmp_file, 'dhcp-server/dhcpd.conf.j2', dhcp,
+ formater=lambda _: _.replace("&quot;", '"'))
+ # XXX: as we have the ability for a user to pass in "raw" options via VyOS
+ # CLI (see T3544) we now ask ISC dhcpd to test the newly rendered
+ # configuration
+ tmp = run(f'/usr/sbin/dhcpd -4 -q -t -cf {tmp_file}')
+ if tmp > 0:
+ if os.path.exists(tmp_file):
+ os.unlink(tmp_file)
+ raise ConfigError('Configuration file errors encountered - check your options!')
+
+ # Now that we know that the newly rendered configuration is "good" we can
+ # render the "real" configuration
+ render(config_file, 'dhcp-server/dhcpd.conf.j2', dhcp,
+ formater=lambda _: _.replace("&quot;", '"'))
+ render(systemd_override, 'dhcp-server/10-override.conf.j2', dhcp)
+
+ # Clean up configuration test file
+ if os.path.exists(tmp_file):
+ os.unlink(tmp_file)
+
+ return None
+
+def apply(dhcp):
+ call('systemctl daemon-reload')
+ # bail out early - looks like removal from running config
+ if not dhcp or 'disable' in dhcp:
+ call('systemctl stop isc-dhcp-server.service')
+ if os.path.exists(config_file):
+ os.unlink(config_file)
+
+ return None
+
+ call('systemctl restart isc-dhcp-server.service')
+ return None
+
+if __name__ == '__main__':
+ try:
+ c = get_config()
+ verify(c)
+ generate(c)
+ apply(c)
+ except ConfigError as e:
+ print(e)
+ exit(1)