Merge branch 't652-rewrite-snmp' into current

* t652-rewrite-snmp:
  T652: Add SNMPv3 TSM handling and commit verification
  T655: Add support for SNMPv3 'noAuthNoPriv' security level
  T652: read SNMPv3 config into python dictionary
  snmp.py: refactor listen-address config generation
  T654: Support IPv6 configuration for SNMP listen address
  T652: first SNMP version using XML interface definition

1 files changed, 709 insertions, 0 deletions

diff --git a/src/conf_mode/snmp.py b/src/conf_mode/snmp.py
new file mode 100755
index 000000000..429181550
--- /dev/null
+++ b/src/conf_mode/snmp.py
@@ -0,0 +1,709 @@
+#!/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 sys
+import os
+import stat
+import pwd
+
+import jinja2
+import ipaddress
+import random
+import binascii
+import re
+
+import vyos.version
+
+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'
+
+# SNMPS template - be careful if you edit the template.
+client_config_tmpl = """
+### Autogenerated by snmp.py ###
+{% if trap_source -%}
+clientaddr {{ trap_source }}
+{% endif %}
+
+"""
+
+# SNMPS template - be careful if you edit the template.
+access_config_tmpl = """
+### Autogenerated by snmp.py ###
+{% if v3_users %}
+{% for u in v3_users %}
+{{ u.mode }}user {{ u.name }}
+{% endfor %}
+{% endif -%}
+rwuser {{ vyos_user }}
+
+"""
+
+# SNMPS template - be careful if you edit the template.
+user_config_tmpl = """
+### Autogenerated by snmp.py ###
+# user
+{% if v3_users %}
+{% for u in v3_users %}
+createUser {{ u.name }} {{ u.authProtocol | upper }} {% if u.authPassword %} "{{ u.authPassword }}" {% elif u.authMasterKey %} "{{ u.authMasterKey }}"{% endif %} {{ u.privProtocol | upper }}{% if u.privPassword %} {{ u.privPassword }}{% elif u.privMasterKey %} {{ u.privMasterKey }}{% endif %}
+{% endfor %}
+{% endif %}
+
+createUser {{ vyos_user }} MD5 "{{ vyos_user_pass }}" DES
+"""
+
+# SNMPS template - 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 0755 0755
+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
+smuxpeer .1.3.6.1.4.1.3317.1.2.2
+smuxpeer .1.3.6.1.4.1.3317.1.2.3
+smuxpeer .1.3.6.1.4.1.3317.1.2.5
+smuxpeer .1.3.6.1.4.1.3317.1.2.8
+smuxpeer .1.3.6.1.4.1.3317.1.2.9
+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 #
+########################
+
+{% if v3_tsm_key %}
+[snmp] localCert {{ v3_tsm_key }}
+{% endif %}
+
+# Default system description is VyOS version
+sysDescr VyOS {{ version }}
+
+{% if description -%}
+# Description
+SysDescr {{ description }}
+{% endif %}
+
+# Listen
+agentaddress unix:/run/snmpd.socket{% for li in listen_on %},{{ li }}{% endfor %}{% if v3_tsm_key %},tlstcp:{{ v3_tsm_port }},dtlsudp::{{ v3_tsm_port }}{% endif %}
+
+
+# SNMP communities
+{% if communities -%}
+{% for c in communities %}
+{% if c.network -%}
+{% for network in c.network %}
+{{ c.authorization }}community {{ c.name }} {{ network }}
+{% endfor %}
+{% else %}
+{{ c.authorization }}community {{ c.name }}
+{% endif %}
+{% endfor %}
+{% endif %}
+
+{% 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 %}
+
+#
+# SNMPv3 stuff goes here
+#
+{% if v3_enabled %}
+
+# views
+{% if v3_views -%}
+{% for v in v3_views %}
+{% for oid in v.oids %}
+view {{ v.name }} included .{{ oid.oid }}
+{% endfor %}
+{% endfor %}
+{% endif %}
+
+# access
+#             context sec.model sec.level match  read    write  notif
+{% if v3_groups -%}
+{% for g in v3_groups %}
+access {{ g.name }} "" usm {{ g.seclevel }} exact {{ g.view }} none none
+access {{ g.name }} "" tsm {{ g.seclevel }} exact {{ g.view }} none none
+{% endfor -%}
+{% endif %}
+
+# trap-target
+{% if v3_traps -%}
+{% for t in v3_traps %}
+trapsess -v 3 {{ '-Ci' if t.type == 'inform' }} -e {{ t.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 -%}
+{% endif %}
+
+# group
+{% if v3_users -%}
+{% for u in v3_users %}
+group {{ u.group }} usm {{ u.name }}
+group {{ u.group }} tsm {{ u.name }}
+{% endfor %}
+{% endif %}
+
+{% endif %}
+
+"""
+
+default_config_data = {
+    'listen_on': [],
+    '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_tsm_key': '',
+    'v3_tsm_port': '10161',
+    'v3_users': [],
+    'v3_views': []
+}
+
+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 'vyattaxxxxxxxxxxxxxxxx'
+    # os.urandom(8) returns 8 bytes of random data
+    snmp['vyos_user'] = 'vyatta' + binascii.hexlify(os.urandom(8)).decode('utf-8')
+    snmp['vyos_user_pass'] = binascii.hexlify(os.urandom(16)).decode('utf-8')
+
+    if conf.exists('community'):
+        for name in conf.list_nodes('community'):
+            community = {
+                'name': name,
+                'authorization': 'ro',
+                'network': []
+            }
+
+            if conf.exists('community {0} authorization'.format(name)):
+                community['authorization'] = conf.return_value('community {0} authorization'.format(name))
+
+            if conf.exists('community {0} network'.format(name)):
+                community['network'] = conf.return_values('community {0} network'.format(name))
+
+            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'):
+            listen = ''
+            port = '161'
+            if conf.exists('listen-address {0} port'.format(addr)):
+                port = conf.return_value('listen-address {0} port'.format(addr))
+
+            if ipaddress.ip_address(addr).version == 4:
+                # udp:127.0.0.1:161
+                listen = 'udp:' + addr + ':' + port
+            elif ipaddress.ip_address(addr).version == 6:
+                # udp6:[::1]:161
+                listen = 'udp6:' + '[' + addr + ']' + ':' + port
+            else:
+                raise ConfigError('Invalid IP address version')
+
+            snmp['listen_on'].append(listen)
+
+    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)
+
+    #########################################################################
+    #                ____  _   _ __  __ ____          _____                 #
+    #               / ___|| \ | |  \/  |  _ \  __   _|___ /                 #
+    #               \___ \|  \| | |\/| | |_) | \ \ / / |_ \                 #
+    #                ___) | |\  | |  | |  __/   \ 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,
+                'engineID': '',
+                'secName': '',
+                'authProtocol': 'md5',
+                'authPassword': '',
+                'authMasterKey': '',
+                'privProtocol': 'des',
+                'privPassword': '',
+                'privMasterKey': '',
+                'ipProto': 'udp',
+                'ipPort': '162',
+                'type': '',
+                'secLevel': 'noAuthNoPriv'
+            }
+
+            if conf.exists('v3 trap-target {0} engineid'.format(trap)):
+                # Set the context engineID used for SNMPv3 REQUEST messages scopedPdu.
+                # If not specified, this will default to the authoritative engineID.
+                trap_cfg['engineID'] = conf.return_value('v3 trap-target {0} engineid'.format(trap))
+
+            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 tsm'
+    #
+    if conf.exists('v3 tsm'):
+        if conf.exists('v3 tsm local-key'):
+            snmp['v3_tsm_key'] = conf.return_value('v3 tsm local-key')
+
+        if conf.exists('v3 tsm port'):
+            snmp['v3_tsm_port'] = conf.return_value('v3 tsm port')
+
+    #
+    # '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': '',
+                'engineID': '',
+                'group': '',
+                'mode': 'ro',
+                'privMasterKey': '',
+                'privPassword': '',
+                'privTsmKey': '',
+                'privProtocol': ''
+            }
+
+            #
+            # 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))
+
+            if conf.exists('v3 user {0} auth type'.format(user)):
+                user_cfg['authProtocol'] = conf.return_value('v3 user {0} auth type'.format(user))
+
+            #
+            # v3 user {0} engineid
+            #
+            if conf.exists('v3 user {0} engineid'.format(user)):
+                user_cfg['engineID'] = conf.return_value('v3 user {0} engineid'.format(user))
+
+            #
+            # 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))
+
+            if conf.exists('v3 user {0} privacy tsm-key'.format(user)):
+                user_cfg['privTsmKey'] = conf.return_value('v3 user {0} privacy tsm-key'.format(user))
+
+            if conf.exists('v3 user {0} privacy type'.format(user)):
+                user_cfg['privProtocol'] = conf.return_value('v3 user {0} privacy type'.format(user))
+
+            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:
+        return None
+
+    # bail out early if SNMP v3 is not configured
+    if not snmp['v3_enabled']:
+        return None
+
+    tsmKeyPattern = re.compile('^[0-9A-F]{2}(:[0-9A-F]{2}){19}$', re.IGNORECASE)
+
+    if snmp['v3_tsm_key']:
+        if not tsmKeyPattern.match(snmp['v3_tsm_key']):
+            if not os.path.isfile('/etc/snmp/tls/certs/' + snmp['v3_tsm_key']):
+                if not os.path.isfile('/config/snmp/tls/certs/' + snmp['v3_tsm_key']):
+                    raise ConfigError('TSM key must be fingerprint or filename in "/config/snmp/tls/certs/" folder')
+
+    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 'type' in trap.keys():
+                if trap['type'] == 'trap' and trap['engineID'] == '':
+                    raise ConfigError('must specify engineid if type is "trap"')
+            else:
+                raise ConfigError('"type" must be specified')
+
+
+    if 'v3_users' in snmp.keys():
+        for user in snmp['v3_users']:
+            if user['authPassword'] and user['authMasterKey']:
+                raise ConfigError('Can not mix "encrypted-key" and "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['authPassword'] == '' and user['authMasterKey'] == '' and user['privTsmKey'] == '':
+                raise ConfigError('Must specify auth or tsm-key for user auth')
+
+            if user['privProtocol'] == '':
+                raise ConfigError('Must specify privacy type')
+
+            if user['mode'] == '':
+                raise ConfigError('Must specify user mode ro/rw')
+
+            if user['privTsmKey']:
+                if not tsmKeyPattern.match(snmp['v3_tsm_key']):
+                    if not os.path.isfile('/etc/snmp/tls/certs/' + snmp['v3_tsm_key']):
+                        if not os.path.isfile('/config/snmp/tls/certs/' + snmp['v3_tsm_key']):
+                            raise ConfigError('User TSM key must be fingerprint or filename in "/config/snmp/tls/certs/" folder')
+
+            if user['group']:
+                #
+                # Group must exist prior to mapping it into a group
+                #
+                error = True
+                if 'v3_groups' in snmp.keys():
+                    for group in snmp['v3_groups']:
+                        if group['name'] == user['group']:
+                            error = False
+                if error:
+                    raise ConfigError('You must create group "{0}" first'.format(user['group']))
+
+
+    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, trim_blocks=True)
+    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, trim_blocks=True)
+    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, trim_blocks=True)
+    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, trim_blocks=True)
+    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:
+
+        if not os.path.exists('/config/snmp/tls'):
+            os.makedirs('/config/snmp/tls')
+            os.chmod('/config/snmp/tls', stat.S_IWUSR | stat.S_IRUSR)
+            # get uid for user 'snmp'
+            snmp_uid = pwd.getpwnam('snmp').pw_uid
+            os.chown('/config/snmp/tls', snmp_uid, -1)
+
+        # start SNMP daemon
+        os.system("sudo systemctl restart snmpd.service")
+
+    return None
+
+if __name__ == '__main__':
+    try:
+        c = get_config()
+        verify(c)
+        generate(c)
+        apply(c)
+    except ConfigError as e:
+        print(e)
+        sys.exit(1)