dhcp.py
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dhcp.py
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	#!/usr/bin/env python3
	#
	# Copyright (C) 2022-2025 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
	import sys
	import typing

	from datetime import datetime
	from glob import glob
	from ipaddress import ip_address
	from tabulate import tabulate

	import vyos.opmode

	from vyos.base import Warning
	from vyos.configquery import ConfigTreeQuery

	from vyos.kea import kea_get_active_config
	from vyos.kea import kea_get_dhcp_pools
	from vyos.kea import kea_get_leases
	from vyos.kea import kea_get_server_leases
	from vyos.kea import kea_get_static_mappings
	from vyos.kea import kea_delete_lease
	from vyos.utils.process import call
	from vyos.utils.process import is_systemd_service_running

	time_string = "%a %b %d %H:%M:%S %Z %Y"

	config = ConfigTreeQuery()
	lease_valid_states = ['all', 'active', 'free', 'expired', 'released', 'abandoned', 'reset', 'backup']
	sort_valid_inet = ['end', 'mac', 'hostname', 'ip', 'pool', 'remaining', 'start', 'state']
	sort_valid_inet6 = ['end', 'duid', 'ip', 'last_communication', 'pool', 'remaining', 'state', 'type']
	mapping_sort_valid = ['mac', 'ip', 'pool', 'duid']

	ArgFamily = typing.Literal['inet', 'inet6']
	ArgState = typing.Literal['all', 'active', 'free', 'expired', 'released', 'abandoned', 'reset', 'backup']
	ArgOrigin = typing.Literal['local', 'remote']

	def _utc_to_local(utc_dt):
	return datetime.fromtimestamp((datetime.fromtimestamp(utc_dt) - datetime(1970, 1, 1)).total_seconds())


	def _get_raw_server_leases(config, family='inet', pool=None, sorted=None, state=[], origin=None) -> list:
	inet_suffix = '6' if family == 'inet6' else '4'
	pools = [pool] if pool else kea_get_dhcp_pools(config, inet_suffix)

	mappings = kea_get_server_leases(config, inet_suffix, pools, state, origin)

	if sorted:
	if sorted == 'ip':
	mappings.sort(key = lambda x:ip_address(x['ip']))
	else:
	mappings.sort(key = lambda x:x[sorted])
	return mappings


	def _get_formatted_server_leases(raw_data, family='inet'):
	data_entries = []
	if family == 'inet':
	for lease in raw_data:
	ipaddr = lease.get('ip')
	hw_addr = lease.get('mac')
	state = lease.get('state')
	start = lease.get('start')
	start = _utc_to_local(start).strftime('%Y/%m/%d %H:%M:%S')
	end = lease.get('end')
	end = _utc_to_local(end).strftime('%Y/%m/%d %H:%M:%S') if end else '-'
	remain = lease.get('remaining')
	pool = lease.get('pool')
	hostname = lease.get('hostname')
	origin = lease.get('origin')
	data_entries.append([ipaddr, hw_addr, state, start, end, remain, pool, hostname, origin])

	headers = ['IP Address', 'MAC address', 'State', 'Lease start', 'Lease expiration', 'Remaining', 'Pool',
	'Hostname', 'Origin']

	if family == 'inet6':
	for lease in raw_data:
	ipaddr = lease.get('ip')
	state = lease.get('state')
	start = lease.get('last_communication')
	start = _utc_to_local(start).strftime('%Y/%m/%d %H:%M:%S')
	end = lease.get('end')
	end = _utc_to_local(end).strftime('%Y/%m/%d %H:%M:%S')
	remain = lease.get('remaining')
	lease_type = lease.get('type')
	pool = lease.get('pool')
	host_identifier = lease.get('duid')
	data_entries.append([ipaddr, state, start, end, remain, lease_type, pool, host_identifier])

	headers = ['IPv6 address', 'State', 'Last communication', 'Lease expiration', 'Remaining', 'Type', 'Pool',
	'DUID']

	output = tabulate(data_entries, headers, numalign='left')
	return output


	def _get_pool_size(pool, family='inet'):
	v = 'v6' if family == 'inet6' else ''
	base = f'service dhcp{v}-server shared-network-name {pool}'
	size = 0
	subnets = config.list_nodes(f'{base} subnet')
	for subnet in subnets:
	ranges = config.list_nodes(f'{base} subnet {subnet} range')
	for range in ranges:
	if family == 'inet6':
	start = config.value(f'{base} subnet {subnet} range {range} start')
	stop = config.value(f'{base} subnet {subnet} range {range} stop')
	else:
	start = config.value(f'{base} subnet {subnet} range {range} start')
	stop = config.value(f'{base} subnet {subnet} range {range} stop')
	# Add +1 because both range boundaries are inclusive
	size += int(ip_address(stop)) - int(ip_address(start)) + 1
	return size


	def _get_raw_pool_statistics(config, family='inet', pool=None):
	inet_suffix = '6' if family == 'inet6' else '4'
	pools = [pool] if pool else kea_get_dhcp_pools(config, inet_suffix)

	stats = []
	for p in pools:
	size = _get_pool_size(family=family, pool=p)
	leases = len(_get_raw_server_leases(config, family=family, pool=p))
	use_percentage = round(leases / size * 100) if size != 0 else 0
	pool_stats = {'pool': p, 'size': size, 'leases': leases,
	'available': (size - leases), 'use_percentage': use_percentage}
	stats.append(pool_stats)
	return stats


	def _get_formatted_pool_statistics(pool_data, family='inet'):
	data_entries = []
	for entry in pool_data:
	pool = entry.get('pool')
	size = entry.get('size')
	leases = entry.get('leases')
	available = entry.get('available')
	use_percentage = entry.get('use_percentage')
	use_percentage = f'{use_percentage}%'
	data_entries.append([pool, size, leases, available, use_percentage])

	headers = ['Pool', 'Size','Leases', 'Available', 'Usage']
	output = tabulate(data_entries, headers, numalign='left')
	return output


	def _get_raw_server_static_mappings(config, family='inet', pool=None, sorted=None):

	inet_suffix = '6' if family == 'inet6' else '4'
	pools = [pool] if pool else kea_get_dhcp_pools(config, inet_suffix)

	mappings = kea_get_static_mappings(config, inet_suffix, pools)

	if sorted:
	if sorted == 'ip':
	mappings.sort(key = lambda x:ip_address(x['ip']))
	else:
	mappings.sort(key = lambda x:x[sorted])
	return mappings


	def _get_formatted_server_static_mappings(raw_data, family='inet'):
	data_entries = []
	if family == 'inet':
	for entry in raw_data:
	pool = entry.get('pool')
	subnet = entry.get('subnet')
	hostname = entry.get('hostname')
	ip_addr = entry.get('ip', 'N/A')
	mac_addr = entry.get('mac', 'N/A')
	duid = entry.get('duid', 'N/A')
	description = entry.get('description', 'N/A')
	data_entries.append([pool, subnet, hostname, ip_addr, mac_addr, duid, description])
	elif family == 'inet6':
	for entry in raw_data:
	pool = entry.get('pool')
	subnet = entry.get('subnet')
	hostname = entry.get('hostname')
	ip_addr = entry.get('ip', 'N/A')
	mac_addr = entry.get('mac', 'N/A')
	duid = entry.get('duid', 'N/A')
	description = entry.get('description', 'N/A')
	data_entries.append([pool, subnet, hostname, ip_addr, mac_addr, duid, description])

	headers = ['Pool', 'Subnet', 'Hostname', 'IP Address', 'MAC Address', 'DUID', 'Description']
	output = tabulate(data_entries, headers, numalign='left')
	return output

	def _verify(func):
	"""Decorator checks if DHCP(v6) config exists"""
	from functools import wraps

	@wraps(func)
	def _wrapper(args, *kwargs):
	config = ConfigTreeQuery()
	family = kwargs.get('family')
	v = 'v6' if family == 'inet6' else ''
	unconf_message = f'DHCP{v} server is not configured'
	# Check if config does not exist
	if not config.exists(f'service dhcp{v}-server'):
	raise vyos.opmode.UnconfiguredSubsystem(unconf_message)
	return func(args, *kwargs)
	return _wrapper

	def _verify_client(func):
	"""Decorator checks if interface is configured as DHCP client"""
	from functools import wraps
	from vyos.ifconfig import Section

	@wraps(func)
	def _wrapper(args, *kwargs):
	config = ConfigTreeQuery()
	family = kwargs.get('family')
	v = 'v6' if family == 'inet6' else ''
	interface = kwargs.get('interface')
	interface_path = Section.get_config_path(interface)
	unconf_message = f'DHCP{v} client not configured on interface {interface}!'

	# Check if config does not exist
	if not config.exists(f'interfaces {interface_path} address dhcp{v}'):
	raise vyos.opmode.UnconfiguredObject(unconf_message)
	return func(args, *kwargs)
	return _wrapper

	@_verify
	def show_pool_statistics(raw: bool, family: ArgFamily, pool: typing.Optional[str]):

	v = 'v6' if family == 'inet6' else ''
	inet_suffix = '6' if family == 'inet6' else '4'

	if not is_systemd_service_running(f'kea-dhcp{inet_suffix}-server.service'):
	Warning('DHCP server is configured but not started. Data may be stale.')

	try:
	active_config = kea_get_active_config(inet_suffix)
	except Exception:
	raise vyos.opmode.DataUnavailable('Cannot fetch DHCP server configuration')

	active_pools = kea_get_dhcp_pools(active_config, inet_suffix)

	if pool and active_pools and pool not in active_pools:
	raise vyos.opmode.IncorrectValue(f'DHCP{v} pool "{pool}" does not exist!')

	pool_data = _get_raw_pool_statistics(active_config, family=family, pool=pool)
	if raw:
	return pool_data
	else:
	return _get_formatted_pool_statistics(pool_data, family=family)


	@_verify
	def show_server_leases(raw: bool, family: ArgFamily, pool: typing.Optional[str],
	sorted: typing.Optional[str], state: typing.Optional[ArgState],
	origin: typing.Optional[ArgOrigin] ):

	v = 'v6' if family == 'inet6' else ''
	inet_suffix = '6' if family == 'inet6' else '4'

	if not is_systemd_service_running(f'kea-dhcp{inet_suffix}-server.service'):
	Warning('DHCP server is configured but not started. Data may be stale.')

	try:
	active_config = kea_get_active_config(inet_suffix)
	except Exception:
	raise vyos.opmode.DataUnavailable('Cannot fetch DHCP server configuration')

	active_pools = kea_get_dhcp_pools(active_config, inet_suffix)

	if pool and active_pools and pool not in active_pools:
	raise vyos.opmode.IncorrectValue(f'DHCP{v} pool "{pool}" does not exist!')

	sort_valid = sort_valid_inet6 if family == 'inet6' else sort_valid_inet
	if sorted and sorted not in sort_valid:
	raise vyos.opmode.IncorrectValue(f'DHCP{v} sort "{sorted}" is invalid!')

	if state and state not in lease_valid_states:
	raise vyos.opmode.IncorrectValue(f'DHCP{v} state "{state}" is invalid!')

	lease_data = _get_raw_server_leases(config=active_config, family=family, pool=pool, sorted=sorted, state=state, origin=origin)
	if raw:
	return lease_data
	else:
	return _get_formatted_server_leases(lease_data, family=family)

	@_verify
	def show_server_static_mappings(raw: bool, family: ArgFamily, pool: typing.Optional[str],
	sorted: typing.Optional[str]):
	v = 'v6' if family == 'inet6' else ''
	inet_suffix = '6' if family == 'inet6' else '4'

	if not is_systemd_service_running(f'kea-dhcp{inet_suffix}-server.service'):
	Warning('DHCP server is configured but not started. Data may be stale.')

	try:
	active_config = kea_get_active_config(inet_suffix)
	except Exception:
	raise vyos.opmode.DataUnavailable('Cannot fetch DHCP server configuration')

	active_pools = kea_get_dhcp_pools(active_config, inet_suffix)

	if pool and active_pools and pool not in active_pools:
	raise vyos.opmode.IncorrectValue(f'DHCP{v} pool "{pool}" does not exist!')

	if sorted and sorted not in mapping_sort_valid:
	raise vyos.opmode.IncorrectValue(f'DHCP{v} sort "{sorted}" is invalid!')

	static_mappings = _get_raw_server_static_mappings(config=active_config, family=family, pool=pool, sorted=sorted)
	if raw:
	return static_mappings
	else:
	return _get_formatted_server_static_mappings(static_mappings, family=family)

	def _lease_valid(inet, address):
	leases = kea_get_leases(inet)
	return any(lease['ip-address'] == address for lease in leases)

	@_verify
	def clear_dhcp_server_lease(family: ArgFamily, address: str):
	v = 'v6' if family == 'inet6' else ''
	inet = '6' if family == 'inet6' else '4'

	if not _lease_valid(inet, address):
	print(f'Lease not found on DHCP{v} server')
	return None

	if not kea_delete_lease(inet, address):
	print(f'Failed to clear lease for "{address}"')
	return None

	print(f'Lease "{address}" has been cleared')

	def _get_raw_client_leases(family='inet', interface=None):
	from time import mktime
	from datetime import datetime
	from vyos.defaults import directories
	from vyos.utils.network import get_interface_vrf

	lease_dir = directories['isc_dhclient_dir']
	lease_files = []
	lease_data = []

	if interface:
	tmp = f'{lease_dir}/dhclient_{interface}.lease'
	if os.path.exists(tmp):
	lease_files.append(tmp)
	else:
	# All DHCP leases
	lease_files = glob(f'{lease_dir}/dhclient_*.lease')

	for lease in lease_files:
	tmp = {}
	with open(lease, 'r') as f:
	for line in f.readlines():
	line = line.rstrip()
	if 'last_update' not in tmp:
	# ISC dhcp client contains least_update timestamp in human readable
	# format this makes less sense for an API and also the expiry
	# timestamp is provided in UNIX time. Convert string (e.g. Sun Jul
	# 30 18:13:44 CEST 2023) to UNIX time (1690733624)
	tmp.update({'last_update' : int(mktime(datetime.strptime(line, time_string).timetuple()))})
	continue

	k, v = line.split('=')
	tmp.update({k : v.replace("'", "")})

	if 'interface' in tmp:
	vrf = get_interface_vrf(tmp['interface'])
	if vrf:
	tmp.update({'vrf' : vrf})

	lease_data.append(tmp)

	return lease_data

	def _get_formatted_client_leases(lease_data, family):
	from time import localtime
	from time import strftime

	from vyos.utils.network import is_intf_addr_assigned

	data_entries = []
	for lease in lease_data:
	if not lease.get('new_ip_address'):
	continue
	data_entries.append(["Interface", lease['interface']])
	if 'new_ip_address' in lease:
	tmp = '[Active]' if is_intf_addr_assigned(lease['interface'], lease['new_ip_address']) else '[Inactive]'
	data_entries.append(["IP address", lease['new_ip_address'], tmp])
	if 'new_subnet_mask' in lease:
	data_entries.append(["Subnet Mask", lease['new_subnet_mask']])
	if 'new_domain_name' in lease:
	data_entries.append(["Domain Name", lease['new_domain_name']])
	if 'new_routers' in lease:
	data_entries.append(["Router", lease['new_routers']])
	if 'new_domain_name_servers' in lease:
	data_entries.append(["Name Server", lease['new_domain_name_servers']])
	if 'new_dhcp_server_identifier' in lease:
	data_entries.append(["DHCP Server", lease['new_dhcp_server_identifier']])
	if 'new_dhcp_lease_time' in lease:
	data_entries.append(["DHCP Server", lease['new_dhcp_lease_time']])
	if 'vrf' in lease:
	data_entries.append(["VRF", lease['vrf']])
	if 'last_update' in lease:
	tmp = strftime(time_string, localtime(int(lease['last_update'])))
	data_entries.append(["Last Update", tmp])
	if 'new_expiry' in lease:
	tmp = strftime(time_string, localtime(int(lease['new_expiry'])))
	data_entries.append(["Expiry", tmp])

	# Add empty marker
	data_entries.append([''])

	output = tabulate(data_entries, tablefmt='plain')

	return output

	def show_client_leases(raw: bool, family: ArgFamily, interface: typing.Optional[str]):
	lease_data = _get_raw_client_leases(family=family, interface=interface)
	if raw:
	return lease_data
	else:
	return _get_formatted_client_leases(lease_data, family=family)

	@_verify_client
	def renew_client_lease(raw: bool, family: ArgFamily, interface: str):
	if not raw:
	v = 'v6' if family == 'inet6' else ''
	print(f'Restarting DHCP{v} client on interface {interface}...')
	if family == 'inet6':
	call(f'systemctl restart dhcp6c@{interface}.service')
	else:
	call(f'systemctl restart dhclient@{interface}.service')

	@_verify_client
	def release_client_lease(raw: bool, family: ArgFamily, interface: str):
	if not raw:
	v = 'v6' if family == 'inet6' else ''
	print(f'Release DHCP{v} client on interface {interface}...')
	if family == 'inet6':
	call(f'systemctl stop dhcp6c@{interface}.service')
	else:
	call(f'systemctl stop dhclient@{interface}.service')

	if __name__ == '__main__':
	try:
	res = vyos.opmode.run(sys.modules[__name__])
	if res:
	print(res)
	except (ValueError, vyos.opmode.Error) as e:
	print(e)
	sys.exit(1)

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