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dhcp.py
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dhcp.py
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#!/usr/bin/env python3
#
# Copyright (C) 2022-2023 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
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_pool_from_subnet_id
from vyos.kea import kea_parse_leases
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', 'iaid_duid', 'ip', 'last_communication', 'pool', 'remaining', 'state', 'type']
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 _format_hex_string(in_str):
out_str = ""
# if input is divisible by 2, add : every 2 chars
if len(in_str) > 0 and len(in_str) % 2 == 0:
out_str = ':'.join(a+b for a,b in zip(in_str[::2], in_str[1::2]))
else:
out_str = in_str
return out_str
def _find_list_of_dict_index(lst, key='ip', value='') -> int:
"""
Find the index entry of list of dict matching the dict value
Exampe:
% lst = [{'ip': '192.0.2.1'}, {'ip': '192.0.2.2'}]
% _find_list_of_dict_index(lst, key='ip', value='192.0.2.2')
% 1
"""
idx = next((index for (index, d) in enumerate(lst) if d[key] == value), None)
return idx
def _get_raw_server_leases(family='inet', pool=None, sorted=None, state=[], origin=None) -> list:
"""
Get DHCP server leases
:return list
"""
inet_suffix = '6' if family == 'inet6' else '4'
lease_file = f'/config/dhcp/dhcp{inet_suffix}-leases.csv'
leases = kea_parse_leases(lease_file)
if pool is None:
pool = _get_dhcp_pools(family=family)
else:
pool = [pool]
active_config = kea_get_active_config(inet_suffix)
data = []
for lease in leases:
data_lease = {}
data_lease['ip'] = lease['address']
lease_state_long = {'0': 'active', '1': 'rejected', '2': 'expired'}
data_lease['state'] = lease_state_long[lease['state']]
data_lease['pool'] = kea_get_pool_from_subnet_id(active_config, inet_suffix, lease['subnet_id']) if active_config else '-'
data_lease['end'] = lease['expire_timestamp'].timestamp() if lease['expire_timestamp'] else None
data_lease['origin'] = 'local' # TODO: Determine remote in HA
if family == 'inet':
data_lease['mac'] = lease['hwaddr']
data_lease['start'] = lease['start_timestamp'].timestamp()
data_lease['hostname'] = lease['hostname']
if family == 'inet6':
data_lease['last_communication'] = lease['start_timestamp'].timestamp()
data_lease['iaid_duid'] = _format_hex_string(lease['duid'])
lease_types_long = {'0': 'non-temporary', '1': 'temporary', '2': 'prefix delegation'}
data_lease['type'] = lease_types_long[lease['lease_type']]
data_lease['remaining'] = '-'
if lease['expire']:
data_lease['remaining'] = lease['expire_timestamp'] - datetime.utcnow()
if data_lease['remaining'].days >= 0:
# substraction gives us a timedelta object which can't be formatted with strftime
# so we use str(), split gets rid of the microseconds
data_lease['remaining'] = str(data_lease["remaining"]).split('.')[0]
# Do not add old leases
if data_lease['remaining'] != '' and data_lease['pool'] in pool and data_lease['state'] != 'free':
if not state or state == 'all' or data_lease['state'] in state:
data.append(data_lease)
# deduplicate
checked = []
for entry in data:
addr = entry.get('ip')
if addr not in checked:
checked.append(addr)
else:
idx = _find_list_of_dict_index(data, key='ip', value=addr)
data.pop(idx)
if sorted:
if sorted == 'ip':
data.sort(key = lambda x:ip_address(x['ip']))
else:
data.sort(key = lambda x:x[sorted])
return data
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('iaid_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',
'IAID_DUID']
output = tabulate(data_entries, headers, numalign='left')
return output
def _get_dhcp_pools(family='inet') -> list:
v = 'v6' if family == 'inet6' else ''
pools = config.list_nodes(f'service dhcp{v}-server shared-network-name')
return pools
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:
if family == 'inet6':
ranges = config.list_nodes(f'{base} subnet {subnet} address-range start')
else:
ranges = config.list_nodes(f'{base} subnet {subnet} range')
for range in ranges:
if family == 'inet6':
start = config.list_nodes(f'{base} subnet {subnet} address-range start')[0]
stop = config.value(f'{base} subnet {subnet} address-range start {start} 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(family='inet', pool=None):
if pool is None:
pool = _get_dhcp_pools(family=family)
else:
pool = [pool]
v = 'v6' if family == 'inet6' else ''
stats = []
for p in pool:
subnet = config.list_nodes(f'service dhcp{v}-server shared-network-name {p} subnet')
size = _get_pool_size(family=family, pool=p)
leases = len(_get_raw_server_leases(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, 'subnet': subnet}
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 _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
@_verify
def show_pool_statistics(raw: bool, family: ArgFamily, pool: typing.Optional[str]):
pool_data = _get_raw_pool_statistics(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] ):
# if dhcp server is down, inactive leases may still be shown as active, so warn the user.
v = '6' if family == 'inet6' else '4'
if not is_systemd_service_running(f'kea-dhcp{v}-server.service'):
Warning('DHCP server is configured but not started. Data may be stale.')
v = 'v6' if family == 'inet6' else ''
if pool and pool not in _get_dhcp_pools(family=family):
raise vyos.opmode.IncorrectValue(f'DHCP{v} pool "{pool}" does not exist!')
if state and state not in lease_valid_states:
raise vyos.opmode.IncorrectValue(f'DHCP{v} state "{state}" is invalid!')
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!')
lease_data = _get_raw_server_leases(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)
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)
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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