snmp.py
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snmp.py
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	#!/usr/bin/env python3
	#
	# Copyright (C) 2018-2019 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 sys
	import os
	import stat
	import pwd
	import jinja2
	import re

	import vyos.version
	import vyos.validate

	from binascii import hexlify
	from shutil import move
	from time import sleep
	from stat import S_IRWXU,S_IXGRP,S_IXOTH,S_IROTH,S_IRGRP
	from vyos.config import Config
	from vyos import ConfigError

	config_file_client = r'/etc/snmp/snmp.conf'
	config_file_daemon = r'/etc/snmp/snmpd.conf'
	config_file_access = r'/usr/share/snmp/snmpd.conf'
	config_file_user = r'/var/lib/snmp/snmpd.conf'
	default_script_dir = r'/config/user-data/'

	# SNMP OIDs used to mark auth/priv type
	OIDs = {
	'md5' : '.1.3.6.1.6.3.10.1.1.2',
	'sha' : '.1.3.6.1.6.3.10.1.1.3',
	'aes' : '.1.3.6.1.6.3.10.1.2.4',
	'des' : '.1.3.6.1.6.3.10.1.2.2',
	'none': '.1.3.6.1.6.3.10.1.2.1'
	}
	# SNMP template (/etc/snmp/snmp.conf) - be careful if you edit the template.
	client_config_tmpl = """
	### Autogenerated by snmp.py ###
	{% if trap_source -%}
	clientaddr {{ trap_source }}
	{% endif %}

	"""

	# SNMP template (/usr/share/snmp/snmpd.conf) - be careful if you edit the template.
	access_config_tmpl = """
	### Autogenerated by snmp.py ###
	{%- for u in v3_users %}
	{{ u.mode }}user {{ u.name }}
	{%- endfor %}

	rwuser {{ vyos_user }}

	"""

	# SNMP template (/var/lib/snmp/snmpd.conf) - be careful if you edit the template.
	user_config_tmpl = """
	### Autogenerated by snmp.py ###
	# user
	{%- for u in v3_users %}
	{%- if u.authOID == 'none' %}
	createUser {{ u.name }}
	{%- elif u.authPassword %}
	createUser {{ u.name }} {{ u.authProtocol \| upper }} "{{ u.authPassword }}" {{ u.privProtocol \| upper }} {{ u.privPassword }}
	{%- else %}
	usmUser 1 3 {{ v3_engineid }} "{{ u.name }}" "{{ u.name }}" NULL {{ u.authOID }} {{ u.authMasterKey }} {{ u.privOID }} {{ u.privMasterKey }} 0x
	{%- endif %}
	{%- endfor %}

	createUser {{ vyos_user }} MD5 "{{ vyos_user_pass }}" DES
	{%- if v3_engineid %}
	oldEngineID {{ v3_engineid }}
	{%- endif %}
	"""

	# SNMP template (/etc/snmp/snmpd.conf) - be careful if you edit the template.
	daemon_config_tmpl = """
	### Autogenerated by snmp.py ###

	# non configurable defaults
	sysObjectID 1.3.6.1.4.1.44641
	sysServices 14
	master agentx
	agentXPerms 0777 0777
	pass .1.3.6.1.2.1.31.1.1.1.18 /opt/vyatta/sbin/if-mib-alias
	smuxpeer .1.3.6.1.2.1.83
	smuxpeer .1.3.6.1.2.1.157
	smuxsocket localhost

	# linkUp/Down configure the Event MIB tables to monitor
	# the ifTable for network interfaces being taken up or down
	# for making internal queries to retrieve any necessary information
	iquerySecName {{ vyos_user }}

	# Modified from the default linkUpDownNotification
	# to include more OIDs and poll more frequently
	notificationEvent linkUpTrap linkUp ifIndex ifDescr ifType ifAdminStatus ifOperStatus
	notificationEvent linkDownTrap linkDown ifIndex ifDescr ifType ifAdminStatus ifOperStatus
	monitor -r 10 -e linkUpTrap "Generate linkUp" ifOperStatus != 2
	monitor -r 10 -e linkDownTrap "Generate linkDown" ifOperStatus == 2

	########################
	# configurable section #
	########################

	# Default system description is VyOS version
	sysDescr VyOS {{ version }}

	{% if description %}
	# Description
	SysDescr {{ description }}
	{%- endif %}

	# Listen
	agentaddress unix:/run/snmpd.socket{% if listen_on %}{% for li in listen_on %},{{ li }}{% endfor %}{% else %},udp:161,udp6:161{% endif %}

	# SNMP communities
	{%- for c in communities %}

	{%- if c.network_v4 %}
	{%- for network in c.network_v4 %}
	{{ c.authorization }}community {{ c.name }} {{ network }}
	{%- endfor %}
	{%- elif not c.has_source %}
	{{ c.authorization }}community {{ c.name }}
	{%- endif %}

	{%- if c.network_v6 %}
	{%- for network in c.network_v6 %}
	{{ c.authorization }}community6 {{ c.name }} {{ network }}
	{%- endfor %}
	{%- elif not c.has_source %}
	{{ c.authorization }}community6 {{ c.name }}
	{%- endif %}

	{%- endfor %}

	{% if contact %}
	# system contact information
	SysContact {{ contact }}
	{%- endif %}

	{% if location %}
	# system location information
	SysLocation {{ location }}
	{%- endif %}

	{% if smux_peers -%}
	# additional smux peers
	{%- for sp in smux_peers %}
	smuxpeer {{ sp }}
	{%- endfor %}
	{%- endif %}

	{% if trap_targets -%}
	# if there is a problem - tell someone!
	{%- for t in trap_targets %}
	trap2sink {{ t.target }}{% if t.port -%}:{{ t.port }}{% endif %} {{ t.community }}
	{%- endfor %}
	{%- endif %}

	{%- if v3_enabled %}
	#
	# SNMPv3 stuff goes here
	#
	# views
	{%- for v in v3_views %}
	{%- for oid in v.oids %}
	view {{ v.name }} included .{{ oid.oid }}
	{%- endfor %}
	{%- endfor %}

	# access
	# context sec.model sec.level match read write notif
	{%- for g in v3_groups %}
	access {{ g.name }} "" usm {{ g.seclevel }} exact {{ g.view }} {% if g.mode == 'ro' %}none{% else %}{{ g.view }}{% endif %} none
	{%- endfor %}

	# trap-target
	{%- for t in v3_traps %}
	trapsess -v 3 {{ '-Ci' if t.type == 'inform' }} -e {{ v3_engineid }} -u {{ t.secName }} -l {{ t.secLevel }} -a {{ t.authProtocol }} {% if t.authPassword %}-A {{ t.authPassword }}{% elif t.authMasterKey %}-3m {{ t.authMasterKey }}{% endif %} -x {{ t.privProtocol }} {% if t.privPassword %}-X {{ t.privPassword }}{% elif t.privMasterKey %}-3M {{ t.privMasterKey }}{% endif %} {{ t.ipProto }}:{{ t.ipAddr }}:{{ t.ipPort }}
	{%- endfor %}

	# group
	{%- for u in v3_users %}
	group {{ u.group }} usm {{ u.name }}
	{% endfor %}
	{%- endif %}

	{% if script_ext %}
	# extension scripts
	{%- for ext in script_ext\|sort(attribute='name') %}
	extend {{ ext.name }} {{ ext.script }}
	{%- endfor %}
	{% endif %}
	"""

	default_config_data = {
	'listen_on': [],
	'listen_address': [],
	'communities': [],
	'smux_peers': [],
	'location' : '',
	'description' : '',
	'contact' : '',
	'trap_source': '',
	'trap_targets': [],
	'vyos_user': '',
	'vyos_user_pass': '',
	'version': '999',
	'v3_enabled': 'False',
	'v3_engineid': '',
	'v3_groups': [],
	'v3_traps': [],
	'v3_users': [],
	'v3_views': [],
	'script_ext': []
	}

	def rmfile(file):
	if os.path.isfile(file):
	os.unlink(file)

	def get_config():
	snmp = default_config_data
	conf = Config()
	if not conf.exists('service snmp'):
	return None
	else:
	conf.set_level('service snmp')

	version_data = vyos.version.get_version_data()
	snmp['version'] = version_data['version']

	# create an internal snmpv3 user of the form 'vyosxxxxxxxxxxxxxxxx'
	# os.urandom(8) returns 8 bytes of random data
	snmp['vyos_user'] = 'vyos' + hexlify(os.urandom(8)).decode('utf-8')
	snmp['vyos_user_pass'] = hexlify(os.urandom(16)).decode('utf-8')

	if conf.exists('community'):
	for name in conf.list_nodes('community'):
	community = {
	'name': name,
	'authorization': 'ro',
	'network_v4': [],
	'network_v6': [],
	'has_source' : False
	}

	if conf.exists('community {0} authorization'.format(name)):
	community['authorization'] = conf.return_value('community {0} authorization'.format(name))

	# Subnet of SNMP client(s) allowed to contact system
	if conf.exists('community {0} network'.format(name)):
	for addr in conf.return_values('community {0} network'.format(name)):
	if vyos.validate.is_ipv4(addr):
	community['network_v4'].append(addr)
	else:
	community['network_v6'].append(addr)

	# IP address of SNMP client allowed to contact system
	if conf.exists('community {0} client'.format(name)):
	for addr in conf.return_values('community {0} client'.format(name)):
	if vyos.validate.is_ipv4(addr):
	community['network_v4'].append(addr)
	else:
	community['network_v6'].append(addr)

	if (len(community['network_v4']) > 0) or (len(community['network_v6']) > 0):
	community['has_source'] = True

	snmp['communities'].append(community)

	if conf.exists('contact'):
	snmp['contact'] = conf.return_value('contact')

	if conf.exists('description'):
	snmp['description'] = conf.return_value('description')

	if conf.exists('listen-address'):
	for addr in conf.list_nodes('listen-address'):
	port = '161'
	if conf.exists('listen-address {0} port'.format(addr)):
	port = conf.return_value('listen-address {0} port'.format(addr))

	snmp['listen_address'].append((addr, port))

	# Always listen on localhost if an explicit address has been configured
	# This is a safety measure to not end up with invalid listen addresses
	# that are not configured on this system. See https://phabricator.vyos.net/T850
	if not '127.0.0.1' in conf.list_nodes('listen-address'):
	snmp['listen_address'].append(('127.0.0.1', '161'))

	if not '::1' in conf.list_nodes('listen-address'):
	snmp['listen_address'].append(('::1', '161'))

	if conf.exists('location'):
	snmp['location'] = conf.return_value('location')

	if conf.exists('smux-peer'):
	snmp['smux_peers'] = conf.return_values('smux-peer')

	if conf.exists('trap-source'):
	snmp['trap_source'] = conf.return_value('trap-source')

	if conf.exists('trap-target'):
	for target in conf.list_nodes('trap-target'):
	trap_tgt = {
	'target': target,
	'community': '',
	'port': ''
	}

	if conf.exists('trap-target {0} community'.format(target)):
	trap_tgt['community'] = conf.return_value('trap-target {0} community'.format(target))

	if conf.exists('trap-target {0} port'.format(target)):
	trap_tgt['port'] = conf.return_value('trap-target {0} port'.format(target))

	snmp['trap_targets'].append(trap_tgt)

	#
	# 'set service snmp script-extensions'
	#
	if conf.exists('script-extensions'):
	for extname in conf.list_nodes('script-extensions extension-name'):
	conf_script = conf.return_value('script-extensions extension-name {} script'.format(extname))
	# if script has not absolute path, use pre configured path
	if "/" not in conf_script:
	conf_script = default_script_dir + conf_script

	extension = {
	'name': extname,
	'script' : conf_script
	}

	snmp['script_ext'].append(extension)

	#########################################################################
	# ____ _ _ __ __ ____ _____ #
	# / ___\|\| \ \| \| \/ \| _ \ __ _\|___ / #
	# \___ \\| \\| \| \|\/\| \| \|_) \| \ \ / / \|_ \ #
	# ___) \| \|\ \| \| \| \| __/ \ V / ___) \| #
	# \|____/\|_\| \_\|_\| \|_\|_\| \_/ \|____/ #
	# #
	# now take care about the fancy SNMP v3 stuff, or bail out eraly #
	#########################################################################
	if not conf.exists('v3'):
	return snmp
	else:
	snmp['v3_enabled'] = True

	# 'set service snmp v3 engineid'
	if conf.exists('v3 engineid'):
	snmp['v3_engineid'] = conf.return_value('v3 engineid')

	# 'set service snmp v3 group'
	if conf.exists('v3 group'):
	for group in conf.list_nodes('v3 group'):
	v3_group = {
	'name': group,
	'mode': 'ro',
	'seclevel': 'auth',
	'view': ''
	}

	if conf.exists('v3 group {0} mode'.format(group)):
	v3_group['mode'] = conf.return_value('v3 group {0} mode'.format(group))

	if conf.exists('v3 group {0} seclevel'.format(group)):
	v3_group['seclevel'] = conf.return_value('v3 group {0} seclevel'.format(group))

	if conf.exists('v3 group {0} view'.format(group)):
	v3_group['view'] = conf.return_value('v3 group {0} view'.format(group))

	snmp['v3_groups'].append(v3_group)

	# 'set service snmp v3 trap-target'
	if conf.exists('v3 trap-target'):
	for trap in conf.list_nodes('v3 trap-target'):
	trap_cfg = {
	'ipAddr': trap,
	'secName': '',
	'authProtocol': 'md5',
	'authPassword': '',
	'authMasterKey': '',
	'privProtocol': 'des',
	'privPassword': '',
	'privMasterKey': '',
	'ipProto': 'udp',
	'ipPort': '162',
	'type': '',
	'secLevel': 'noAuthNoPriv'
	}

	if conf.exists('v3 trap-target {0} user'.format(trap)):
	# Set the securityName used for authenticated SNMPv3 messages.
	trap_cfg['secName'] = conf.return_value('v3 trap-target {0} user'.format(trap))

	if conf.exists('v3 trap-target {0} auth type'.format(trap)):
	# Set the authentication protocol (MD5 or SHA) used for authenticated SNMPv3 messages
	# cmdline option '-a'
	trap_cfg['authProtocol'] = conf.return_value('v3 trap-target {0} auth type'.format(trap))

	if conf.exists('v3 trap-target {0} auth plaintext-key'.format(trap)):
	# Set the authentication pass phrase used for authenticated SNMPv3 messages.
	# cmdline option '-A'
	trap_cfg['authPassword'] = conf.return_value('v3 trap-target {0} auth plaintext-key'.format(trap))

	if conf.exists('v3 trap-target {0} auth encrypted-key'.format(trap)):
	# Sets the keys to be used for SNMPv3 transactions. These options allow you to set the master authentication keys.
	# cmdline option '-3m'
	trap_cfg['authMasterKey'] = conf.return_value('v3 trap-target {0} auth encrypted-key'.format(trap))

	if conf.exists('v3 trap-target {0} privacy type'.format(trap)):
	# Set the privacy protocol (DES or AES) used for encrypted SNMPv3 messages.
	# cmdline option '-x'
	trap_cfg['privProtocol'] = conf.return_value('v3 trap-target {0} privacy type'.format(trap))

	if conf.exists('v3 trap-target {0} privacy plaintext-key'.format(trap)):
	# Set the privacy pass phrase used for encrypted SNMPv3 messages.
	# cmdline option '-X'
	trap_cfg['privPassword'] = conf.return_value('v3 trap-target {0} privacy plaintext-key'.format(trap))

	if conf.exists('v3 trap-target {0} privacy encrypted-key'.format(trap)):
	# Sets the keys to be used for SNMPv3 transactions. These options allow you to set the master encryption keys.
	# cmdline option '-3M'
	trap_cfg['privMasterKey'] = conf.return_value('v3 trap-target {0} privacy encrypted-key'.format(trap))

	if conf.exists('v3 trap-target {0} protocol'.format(trap)):
	trap_cfg['ipProto'] = conf.return_value('v3 trap-target {0} protocol'.format(trap))

	if conf.exists('v3 trap-target {0} port'.format(trap)):
	trap_cfg['ipPort'] = conf.return_value('v3 trap-target {0} port'.format(trap))

	if conf.exists('v3 trap-target {0} type'.format(trap)):
	trap_cfg['type'] = conf.return_value('v3 trap-target {0} type'.format(trap))

	# Determine securityLevel used for SNMPv3 messages (noAuthNoPriv\|authNoPriv\|authPriv).
	# Appropriate pass phrase(s) must provided when using any level higher than noAuthNoPriv.
	if trap_cfg['authPassword'] or trap_cfg['authMasterKey']:
	if trap_cfg['privProtocol'] or trap_cfg['privPassword']:
	trap_cfg['secLevel'] = 'authPriv'
	else:
	trap_cfg['secLevel'] = 'authNoPriv'

	snmp['v3_traps'].append(trap_cfg)

	# 'set service snmp v3 user'
	if conf.exists('v3 user'):
	for user in conf.list_nodes('v3 user'):
	user_cfg = {
	'name': user,
	'authMasterKey': '',
	'authPassword': '',
	'authProtocol': 'md5',
	'authOID': 'none',
	'group': '',
	'mode': 'ro',
	'privMasterKey': '',
	'privPassword': '',
	'privOID': '',
	'privProtocol': 'des'
	}

	# v3 user {0} auth
	if conf.exists('v3 user {0} auth encrypted-key'.format(user)):
	user_cfg['authMasterKey'] = conf.return_value('v3 user {0} auth encrypted-key'.format(user))

	if conf.exists('v3 user {0} auth plaintext-key'.format(user)):
	user_cfg['authPassword'] = conf.return_value('v3 user {0} auth plaintext-key'.format(user))

	# load default value
	type = user_cfg['authProtocol']
	if conf.exists('v3 user {0} auth type'.format(user)):
	type = conf.return_value('v3 user {0} auth type'.format(user))

	# (re-)update with either default value or value from CLI
	user_cfg['authProtocol'] = type
	user_cfg['authOID'] = OIDs[type]

	# v3 user {0} group
	if conf.exists('v3 user {0} group'.format(user)):
	user_cfg['group'] = conf.return_value('v3 user {0} group'.format(user))

	# v3 user {0} mode
	if conf.exists('v3 user {0} mode'.format(user)):
	user_cfg['mode'] = conf.return_value('v3 user {0} mode'.format(user))

	# v3 user {0} privacy
	if conf.exists('v3 user {0} privacy encrypted-key'.format(user)):
	user_cfg['privMasterKey'] = conf.return_value('v3 user {0} privacy encrypted-key'.format(user))

	if conf.exists('v3 user {0} privacy plaintext-key'.format(user)):
	user_cfg['privPassword'] = conf.return_value('v3 user {0} privacy plaintext-key'.format(user))

	# load default value
	type = user_cfg['privProtocol']
	if conf.exists('v3 user {0} privacy type'.format(user)):
	type = conf.return_value('v3 user {0} privacy type'.format(user))

	# (re-)update with either default value or value from CLI
	user_cfg['privProtocol'] = type
	user_cfg['privOID'] = OIDs[type]

	snmp['v3_users'].append(user_cfg)

	# 'set service snmp v3 view'
	if conf.exists('v3 view'):
	for view in conf.list_nodes('v3 view'):
	view_cfg = {
	'name': view,
	'oids': []
	}

	if conf.exists('v3 view {0} oid'.format(view)):
	for oid in conf.list_nodes('v3 view {0} oid'.format(view)):
	oid_cfg = {
	'oid': oid
	}
	view_cfg['oids'].append(oid_cfg)
	snmp['v3_views'].append(view_cfg)

	return snmp

	def verify(snmp):
	if snmp is None:
	# we can not delete SNMP when LLDP is configured with SNMP
	conf = Config()
	if conf.exists('service lldp snmp enable'):
	raise ConfigError('Can not delete SNMP service, as LLDP still uses SNMP!')

	return None

	### check if the configured script actually exist
	if snmp['script_ext']:
	for ext in snmp['script_ext']:
	if not os.path.isfile(ext['script']):
	print ("WARNING: script: {} doesn't exist".format(ext['script']))
	else:
	os.chmod(ext['script'], S_IRWXU\|S_IXGRP\|S_IXOTH\|S_IROTH\|S_IRGRP)

	for listen in snmp['listen_address']:
	addr = listen[0]
	port = listen[1]

	if vyos.validate.is_ipv4(addr):
	# example: udp:127.0.0.1:161
	listen = 'udp:' + addr + ':' + port
	else:
	# example: udp6:[::1]:161
	listen = 'udp6:' + '[' + addr + ']' + ':' + port

	# We only wan't to configure addresses that exist on the system.
	# Hint the user if they don't exist
	if vyos.validate.is_addr_assigned(addr):
	snmp['listen_on'].append(listen)
	else:
	print('WARNING: SNMP listen address {0} not configured!'.format(addr))

	# bail out early if SNMP v3 is not configured
	if not snmp['v3_enabled']:
	return None

	if 'v3_groups' in snmp.keys():
	for group in snmp['v3_groups']:
	#
	# A view must exist prior to mapping it into a group
	#
	if 'view' in group.keys():
	error = True
	if 'v3_views' in snmp.keys():
	for view in snmp['v3_views']:
	if view['name'] == group['view']:
	error = False
	if error:
	raise ConfigError('You must create view "{0}" first'.format(group['view']))
	else:
	raise ConfigError('"view" must be specified')

	if not 'mode' in group.keys():
	raise ConfigError('"mode" must be specified')

	if not 'seclevel' in group.keys():
	raise ConfigError('"seclevel" must be specified')

	if 'v3_traps' in snmp.keys():
	for trap in snmp['v3_traps']:
	if trap['authPassword'] and trap['authMasterKey']:
	raise ConfigError('Must specify only one of encrypted-key/plaintext-key for trap auth')

	if trap['authPassword'] == '' and trap['authMasterKey'] == '':
	raise ConfigError('Must specify encrypted-key or plaintext-key for trap auth')

	if trap['privPassword'] and trap['privMasterKey']:
	raise ConfigError('Must specify only one of encrypted-key/plaintext-key for trap privacy')

	if trap['privPassword'] == '' and trap['privMasterKey'] == '':
	raise ConfigError('Must specify encrypted-key or plaintext-key for trap privacy')

	if not 'type' in trap.keys():
	raise ConfigError('v3 trap: "type" must be specified')

	if not 'authPassword' and 'authMasterKey' in trap.keys():
	raise ConfigError('v3 trap: "auth" must be specified')

	if not 'authProtocol' in trap.keys():
	raise ConfigError('v3 trap: "protocol" must be specified')

	if not 'privPassword' and 'privMasterKey' in trap.keys():
	raise ConfigError('v3 trap: "user" must be specified')

	if 'v3_users' in snmp.keys():
	for user in snmp['v3_users']:
	#
	# Group must exist prior to mapping it into a group
	# seclevel will be extracted from group
	#
	if user['group']:
	error = True
	if 'v3_groups' in snmp.keys():
	for group in snmp['v3_groups']:
	if group['name'] == user['group']:
	seclevel = group['seclevel']
	error = False

	if error:
	raise ConfigError('You must create group "{0}" first'.format(user['group']))

	# Depending on the configured security level
	# the user has to provide additional info
	if user['authPassword'] and user['authMasterKey']:
	raise ConfigError('Can not mix "encrypted-key" and "plaintext-key" for user auth')

	if (not user['authPassword'] and not user['authMasterKey']):
	raise ConfigError('Must specify encrypted-key or plaintext-key for user auth')

	if user['privPassword'] and user['privMasterKey']:
	raise ConfigError('Can not mix "encrypted-key" and "plaintext-key" for user privacy')

	if user['privPassword'] == '' and user['privMasterKey'] == '':
	raise ConfigError('Must specify encrypted-key or plaintext-key for user privacy')

	if user['mode'] == '':
	raise ConfigError('Must specify user mode ro/rw')

	if 'v3_views' in snmp.keys():
	for view in snmp['v3_views']:
	if not view['oids']:
	raise ConfigError('Must configure an oid')

	return None

	def generate(snmp):
	#
	# As we are manipulating the snmpd user database we have to stop it first!
	# This is even save if service is going to be removed
	os.system("sudo systemctl stop snmpd.service")
	rmfile(config_file_client)
	rmfile(config_file_daemon)
	rmfile(config_file_access)
	rmfile(config_file_user)

	if snmp is None:
	return None

	# Write client config file
	tmpl = jinja2.Template(client_config_tmpl)
	config_text = tmpl.render(snmp)
	with open(config_file_client, 'w') as f:
	f.write(config_text)

	# Write server config file
	tmpl = jinja2.Template(daemon_config_tmpl)
	config_text = tmpl.render(snmp)
	with open(config_file_daemon, 'w') as f:
	f.write(config_text)

	# Write access rights config file
	tmpl = jinja2.Template(access_config_tmpl)
	config_text = tmpl.render(snmp)
	with open(config_file_access, 'w') as f:
	f.write(config_text)

	# Write access rights config file
	tmpl = jinja2.Template(user_config_tmpl)
	config_text = tmpl.render(snmp)
	with open(config_file_user, 'w') as f:
	f.write(config_text)

	return None

	def apply(snmp):
	if snmp is not None:

	nonvolatiledir = '/config/snmp/tls'
	volatiledir = '/etc/snmp/tls'
	if not os.path.exists(nonvolatiledir):
	os.makedirs(nonvolatiledir)
	os.chmod(nonvolatiledir, stat.S_IWUSR \| stat.S_IRUSR)
	# get uid for user 'snmp'
	# jessie snmp user = snmp
	# buster snmp user = Debian-snmp
	# keep it backwards compatible for Crux

	un = [x[0] for x in pwd.getpwall()]
	# debian snmp uid is 114 per default across releases
	snmp_uid = 114
	if 'snmp' in un:
	snmp_uid = pwd.getpwnam('snmp').pw_uid
	elif 'Debian-snmp' in un:
	snmp_uid = pwd.getpwnam('Debian-snmp').pw_uid

	os.chown(nonvolatiledir, snmp_uid, -1)

	# move SNMP certificate files from volatile location to non volatile /config/snmp
	if os.path.exists(volatiledir) and os.path.isdir(volatiledir):
	files = os.listdir(volatiledir)
	for f in files:
	move(volatiledir + '/' + f, nonvolatiledir)
	os.chmod(nonvolatiledir + '/' + f, stat.S_IWUSR \| stat.S_IRUSR)

	os.rmdir(volatiledir)
	os.symlink(nonvolatiledir, volatiledir)

	if os.path.islink(volatiledir):
	link = os.readlink(volatiledir)
	if link != nonvolatiledir:
	os.unlink(volatiledir)
	os.symlink(nonvolatiledir, volatiledir)

	# start SNMP daemon
	os.system("sudo systemctl daemon-reload")
	os.system("sudo systemctl restart snmpd.service")

	# Passwords are not available immediately in the configuration file,
	# after daemon startup - we wait until they have been processed by
	# snmpd, which we see when a magic line appears in this file.
	ready = False
	while not ready:
	while not os.path.exists(config_file_user):
	sleep(0.1)

	with open(config_file_user, 'r') as f:
	for line in f:
	# Search for our magic string inside the file
	if 'usmUser' in line:
	ready = True
	break

	# net-snmp is now regenerating the configuration file in the background
	# thus we need to re-open and re-read the file as the content changed.
	# After that we can no read the encrypted password from the config and
	# replace the CLI plaintext password with its encrypted version.
	with open(config_file_user, 'r') as f:
	engineID = ''
	for line in f:
	if line.startswith('usmUser'):
	string = line.split(' ')
	cfg = {
	'user': string[4].replace(r'"', ''),
	'auth_pw': string[8],
	'priv_pw': string[10]
	}
	# No need to take care about the VyOS internal user
	if cfg['user'] == snmp['vyos_user']:
	ready = True
	continue

	# Now update the running configuration
	#
	# Currently when executing os.system() the environment does not have the vyos_libexec_dir variable set, see T685
	os.system('vyos_libexec_dir=/usr/libexec/vyos /opt/vyatta/sbin/my_set service snmp v3 user "{0}" auth encrypted-key {1} > /dev/null'.format(cfg['user'], cfg['auth_pw']))
	os.system('vyos_libexec_dir=/usr/libexec/vyos /opt/vyatta/sbin/my_set service snmp v3 user "{0}" privacy encrypted-key {1} > /dev/null'.format(cfg['user'], cfg['priv_pw']))
	os.system('vyos_libexec_dir=/usr/libexec/vyos /opt/vyatta/sbin/my_delete service snmp v3 user "{0}" auth plaintext-key > /dev/null'.format(cfg['user']))
	os.system('vyos_libexec_dir=/usr/libexec/vyos /opt/vyatta/sbin/my_delete service snmp v3 user "{0}" privacy plaintext-key > /dev/null'.format(cfg['user']))

	# Enable AgentX in FRR
	os.system('vtysh -c "configure terminal" -c "agentx" >/dev/null')

	return None

	if __name__ == '__main__':
	try:
	c = get_config()
	verify(c)
	generate(c)
	apply(c)
	except ConfigError as e:
	print(e)
	sys.exit(1)

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