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#!/usr/bin/env python3
#
# Copyright (C) 2018-2021 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/>.
#
# TODO: merge with show_dhcp.py
from json import dumps
from argparse import ArgumentParser
from ipaddress import ip_address
from tabulate import tabulate
from sys import exit
from collections import OrderedDict
from datetime import datetime
from isc_dhcp_leases import Lease, IscDhcpLeases
from vyos.config import Config
from vyos.util import is_systemd_service_running
lease_file = "/config/dhcpdv6.leases"
pool_key = "shared-networkname"
lease_display_fields = OrderedDict()
lease_display_fields['ip'] = 'IPv6 address'
lease_display_fields['state'] = 'State'
lease_display_fields['last_comm'] = 'Last communication'
lease_display_fields['expires'] = 'Lease expiration'
lease_display_fields['remaining'] = 'Remaining'
lease_display_fields['type'] = 'Type'
lease_display_fields['pool'] = 'Pool'
lease_display_fields['iaid_duid'] = 'IAID_DUID'
lease_valid_states = ['all', 'active', 'free', 'expired', 'released', 'abandoned', 'reset', 'backup']
def in_pool(lease, pool):
if pool_key in lease.sets:
if lease.sets[pool_key] == pool:
return True
return False
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 utc_to_local(utc_dt):
return datetime.fromtimestamp((utc_dt - datetime(1970,1,1)).total_seconds())
def get_lease_data(lease):
data = {}
# isc-dhcp lease times are in UTC so we need to convert them to local time to display
try:
data["expires"] = utc_to_local(lease.end).strftime("%Y/%m/%d %H:%M:%S")
except:
data["expires"] = ""
try:
data["last_comm"] = utc_to_local(lease.last_communication).strftime("%Y/%m/%d %H:%M:%S")
except:
data["last_comm"] = ""
try:
data["remaining"] = lease.end - datetime.utcnow()
# negative timedelta prints wrong so bypass it
if (data["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["remaining"] = str(data["remaining"]).split('.')[0]
else:
data["remaining"] = ""
except:
data["remaining"] = ""
# isc-dhcp records lease declarations as ia_{na|ta|pd} IAID_DUID {...}
# where IAID_DUID is the combined IAID and DUID
data["iaid_duid"] = format_hex_string(lease.host_identifier_string)
lease_types_long = {"na": "non-temporary", "ta": "temporary", "pd": "prefix delegation"}
data["type"] = lease_types_long[lease.type]
data["state"] = lease.binding_state
data["ip"] = lease.ip
try:
data["pool"] = lease.sets[pool_key]
except:
data["pool"] = ""
return data
def get_leases(config, leases, state, pool=None, sort='ip'):
leases = IscDhcpLeases(lease_file).get()
# filter leases by state
if 'all' not in state:
leases = list(filter(lambda x: x.binding_state in state, leases))
# filter leases by pool name
if pool is not None:
if config.exists_effective("service dhcp-server shared-network-name {0}".format(pool)):
leases = list(filter(lambda x: in_pool(x, pool), leases))
else:
print("Pool {0} does not exist.".format(pool))
exit(0)
# should maybe filter all state=active by lease.valid here?
# sort by last_comm time to dedupe (newest lease overrides older)
leases = sorted(leases, key = lambda lease: lease.last_communication)
# dedupe by converting to dict
leases_dict = {}
for lease in leases:
# dedupe by IP
leases_dict[lease.ip] = lease
# convert the lease data
leases = list(map(get_lease_data, leases_dict.values()))
# apply output/display sort
if sort == 'ip':
leases = sorted(leases, key = lambda k: int(ip_address(k['ip'].split('/')[0])))
else:
leases = sorted(leases, key = lambda k: k[sort])
return leases
def show_leases(leases):
lease_list = []
for l in leases:
lease_list_params = []
for k in lease_display_fields.keys():
lease_list_params.append(l[k])
lease_list.append(lease_list_params)
output = tabulate(lease_list, lease_display_fields.values())
print(output)
if __name__ == '__main__':
parser = ArgumentParser()
group = parser.add_mutually_exclusive_group()
group.add_argument("-l", "--leases", action="store_true", help="Show DHCPv6 leases")
group.add_argument("-s", "--statistics", action="store_true", help="Show DHCPv6 statistics")
group.add_argument("--allowed", type=str, choices=["pool", "sort", "state"], help="Show allowed values for argument")
parser.add_argument("-p", "--pool", type=str, help="Show lease for specific pool")
parser.add_argument("-S", "--sort", type=str, default='ip', help="Sort by")
parser.add_argument("-t", "--state", type=str, nargs="+", default=["active"], help="Lease state to show (can specify multiple with spaces)")
parser.add_argument("-j", "--json", action="store_true", default=False, help="Produce JSON output")
args = parser.parse_args()
conf = Config()
if args.allowed == 'pool':
if conf.exists_effective('service dhcpv6-server'):
print(' '.join(conf.list_effective_nodes("service dhcpv6-server shared-network-name")))
exit(0)
elif args.allowed == 'sort':
print(' '.join(lease_display_fields.keys()))
exit(0)
elif args.allowed == 'state':
print(' '.join(lease_valid_states))
exit(0)
elif args.allowed:
parser.print_help()
exit(1)
if args.sort not in lease_display_fields.keys():
print(f'Invalid sort key, choose from: {list(lease_display_fields.keys())}')
exit(0)
if not set(args.state) < set(lease_valid_states):
print(f'Invalid lease state, choose from: {lease_valid_states}')
exit(0)
# Do nothing if service is not configured
if not conf.exists_effective('service dhcpv6-server'):
print("DHCPv6 service is not configured")
exit(0)
# if dhcp server is down, inactive leases may still be shown as active, so warn the user.
if not is_systemd_service_running('isc-dhcp-server6.service'):
print("WARNING: DHCPv6 server is configured but not started. Data may be stale.")
if args.leases:
leases = get_leases(conf, lease_file, args.state, args.pool, args.sort)
if args.json:
print(dumps(leases, indent=4))
else:
show_leases(leases)
elif args.statistics:
print("DHCPv6 statistics option is not available")
else:
parser.print_help()
exit(1)
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