show_dhcpv6.py
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show_dhcpv6.py
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	#!/usr/bin/env python3
	#
	# Copyright (C) 2018 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 json
	import argparse
	import ipaddress
	import tabulate
	import sys
	import collections
	import os
	from datetime import datetime

	from vyos.config import Config
	from isc_dhcp_leases import Lease, IscDhcpLeases

	lease_file = "/config/dhcpdv6.leases"
	pool_key = "shared-networkname"

	lease_display_fields = collections.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(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))
	sys.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(ipaddress.ip_address(k['ip'])))
	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.tabulate(lease_list, lease_display_fields.values())

	print(output)

	if __name__ == '__main__':
	parser = argparse.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, choices=lease_display_fields.keys(), default='ip', help="Sort by")
	parser.add_argument("-t", "--state", type=str, nargs="+", choices=lease_valid_states, 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()

	# Do nothing if service is not configured
	c = Config()
	if not c.exists_effective('service dhcpv6-server'):
	print("DHCPv6 service is not configured")
	sys.exit(0)

	# if dhcp server is down, inactive leases may still be shown as active, so warn the user.
	if os.system('systemctl -q is-active isc-dhcpv6-server.service') != 0:
	print("WARNING: DHCPv6 server is configured but not started. Data may be stale.")

	if args.leases:
	leases = get_leases(lease_file, args.state, args.pool, args.sort)

	if args.json:
	print(json.dumps(leases, indent=4))
	else:
	show_leases(leases)
	elif args.statistics:
	print("DHCPv6 statistics option is not available")
	elif args.allowed == 'pool':
	print(' '.join(c.list_effective_nodes("service dhcpv6-server shared-network-name")))
	elif args.allowed == 'sort':
	print(' '.join(lease_display_fields.keys()))
	elif args.allowed == 'state':
	print(' '.join(lease_valid_states))
	else:
	parser.print_help()

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