summaryrefslogtreecommitdiff
path: root/src/conf_mode/interface-openvpn.py
blob: d63d63acf8b3f4aade0f647c577d0ed5c3b85e5b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
#!/usr/bin/env python3
#
# Copyright (C) 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 os
import re
import pwd
import grp
import sys
import stat
import copy
import jinja2
import psutil
from ipaddress import ip_address,ip_network,IPv4Interface

from signal import SIGUSR1
from subprocess import Popen, PIPE

from vyos.config import Config
from vyos import ConfigError
from vyos.validate import is_addr_assigned

user = 'nobody'
group = 'nogroup'

# Please be careful if you edit the template.
config_tmpl = """
### Autogenerated by interfaces-openvpn.py ###
#
# See https://community.openvpn.net/openvpn/wiki/Openvpn24ManPage
# for individual keyword definition

verb 3
status /opt/vyatta/etc/openvpn/status/{{ intf }}.status 30
writepid /var/run/openvpn/{{ intf }}.pid
daemon openvpn-{{ intf }}

dev-type {{ type }}
dev {{ intf }}
user {{ uid }}
group {{ gid }}
persist-key

proto {% if 'tcp-active' in protocol -%}tcp-client{% elif 'tcp-passive' in protocol -%}tcp-server{% else %}udp{% endif %}

{%- if local_host %}
local {{ local_host }}
{% endif %}

{%- if local_port %}
lport {{ local_port }}
{% endif %}

{%- if remote_port %}
rport {{ remote_port }}
{% endif %}

{%- if remote_host %}
{% for remote in remote_host -%}
remote {{ remote }}
{% endfor -%}
{% endif %}

{%- if shared_secret_file %}
secret {{ shared_secret_file }}
{% endif %}

{%- if persistent_tunnel %}
persist-tun
{% endif %}

{%- if mode %}
{%- if 'client' in mode %}
#
# OpenVPN Client mode
#
client
nobind
{%- elif 'server' in mode %}
#
# OpenVPN Server mode
#
mode server
tls-server
keepalive {{ ping_interval }} {{ ping_restart }}
management /tmp/openvpn-mgmt-intf unix

{%- if server_topology %}
topology {% if 'site-to-site' in server_topology %}p2p{% else %}{{ server_topology }}{% endif %}
{% endif %}

{% for ns in server_dns_nameserver -%}
push "dhcp-option DNS {{ ns }}"
{% endfor -%}

{% for route in server_push_route -%}
push "route {{ route }}"
{% endfor -%}

{%- if server_domain %}
push "dhcp-option DOMAIN {{ server_domain }}"
{% endif %}

{%- if server_max_conn %}
max-clients {{ server_max_conn }}
{% endif %}

{%- if bridge_member %}
server-bridge nogw
{%- else %}
server {{ server_subnet }}
{% endif %}

{%- if server_reject_unconfigured %}
ccd-exclusive
{% endif %}

{%- else %}
#
# OpenVPN site-2-site mode
#
ping {{ ping_interval }}
ping-restart {{ ping_restart }}

{%- if 'tap' in type %}
ifconfig {{ local_address }} {{ local_address_subnet }}
{% else %}
ifconfig {{ local_address }} {{ remote_address }}
{% endif %}

{% endif %}
{% endif %}

{%- if tls_ca_cert %}
ca {{ tls_ca_cert }}
{% endif %}

{%- if tls_cert %}
cert {{ tls_cert }}
{% endif %}

{%- if tls_key %}
key {{ tls_key }}
{% endif %}

{%- if tls_crl %}
crl-verify {{ tls_crl }}
{% endif %}

{%- if tls_dh %}
dh {{ tls_dh }}
{% endif %}

{%- if 'active' in tls_role %}
tls-client
{%- elif 'passive' in tls_role %}
tls-server
{% endif %}

{%- if redirect_gateway %}
push "redirect-gateway {{ redirect_gateway }}"
{% endif %}

{%- if compress_lzo %}
compress lzo
{% endif %}

{%- if hash %}
auth {{ hash }}
{% endif %}

{%- if encryption %}
{%- if 'des' in encryption %}
cipher des-cbc
{%- elif '3des' in encryption %}
cipher des-ede3-cbc
{%- elif 'bf128' in encryption %}
cipher bf-cbc
keysize 128
{%- elif 'bf256' in encryption %}
cipher bf-cbc
keysize 25
{%- elif 'aes128' in encryption %}
cipher aes-128-cbc
{%- elif 'aes192' in encryption %}
cipher aes-192-cbc
{%- elif 'aes256' in encryption %}
cipher aes-256-cbc
{% endif %}
{% endif %}

{%- if auth %}
auth-user-pass /tmp/openvpn-{{ intf }}-pw
auth-retry nointeract
{% endif %}

{%- if client %}
client-config-dir /opt/vyatta/etc/openvpn/ccd/{{ intf }}
{% endif %}

{% for option in options -%}
{{ option }}
{% endfor -%}

{%- if server_2fa_authy_key %}
plugin /usr/lib/authy/authy-openvpn.so https://api.authy.com/protected/json {{ server_2fa_authy_key }} nopam
{% endif %}
"""

client_tmpl = """
### Autogenerated by interfaces-openvpn.py ###

ifconfig-push {{ ip }} {{ remote_netmask }}
{% for route in push_route -%}
push "route {{ route }}"
{% endfor -%}

{% for net in subnet -%}
iroute {{ net }}
{% endfor -%}

{%- if disabled %}
disable
{% endif %}
"""

default_config_data = {
    'address': [],
    'auth_user': '',
    'auth_pass': '',
    'auth': False,
    'bridge_member': [],
    'compress_lzo': False,
    'deleted': False,
    'description': '',
    'disabled': False,
    'encryption': '',
    'hash': '',
    'intf': '',
    'ping_restart': '60',
    'ping_interval': '10',
    'local_address': '',
    'local_address_subnet': '',
    'local_host': '',
    'local_port': '',
    'mode': '',
    'options': [],
    'persistent_tunnel': False,
    'protocol': '',
    'redirect_gateway': '',
    'remote_address': '',
    'remote_host': [],
    'remote_port': '',
    'server_2fa_authy_key': '',
    'server_2fa_authy': [],
    'client': [],
    'server_domain': '',
    'server_max_conn': '',
    'server_dns_nameserver': [],
    'server_push_route': [],
    'server_reject_unconfigured': False,
    'server_subnet': '',
    'server_topology': '',
    'shared_secret_file': '',
    'tls': False,
    'tls_ca_cert': '',
    'tls_cert': '',
    'tls_crl': '',
    'tls_dh': '',
    'tls_key': '',
    'tls_role': '',
    'type': 'tun',
    'uid': user,
    'gid': group,
}

def subprocess_cmd(command):
    p = Popen(command, stdout=PIPE, shell=True)
    p.communicate()

def get_config_name(intf):
    cfg_file = r'/opt/vyatta/etc/openvpn/openvpn-{}.conf'.format(intf)
    return cfg_file

def openvpn_mkdir(directory):
    # create directory on demand
    if not os.path.exists(directory):
        os.mkdir(directory)

    # fix permissions
    os.chmod(directory, stat.S_IRWXU|stat.S_IRWXG|stat.S_IROTH)
    uid = pwd.getpwnam(user).pw_uid
    gid = grp.getgrnam(group).gr_gid
    os.chown(directory, uid, gid)

def fixup_permission(filename, permission=stat.S_IRUSR):
    """
    Check if the given file exists and change ownershit to root/vyattacfg
    and appripriate file access permissions - default is user and group readable
    """
    if os.path.isfile(filename):
        os.chmod(filename, permission)

        # make file owned by root / vyattacfg
        uid = pwd.getpwnam('root').pw_uid
        gid = grp.getgrnam('vyattacfg').gr_gid
        os.chown(filename, uid, gid)

def checkCertHeader(header, filename):
    """
    Verify if filename contains specified header.
    Returns True on success or on file not found to not trigger the exceptions
    """
    if not os.path.isfile(filename):
        return True

    with open(filename, 'r') as f:
        for line in f:
            if re.match(header, line):
                return True

    return False

def get_config():
    openvpn = copy.deepcopy(default_config_data)
    conf = Config()

    # determine tagNode instance
    try:
        openvpn['intf'] = os.environ['VYOS_TAGNODE_VALUE']
    except KeyError as E:
        print("Interface not specified")

    print('Executing for interface ' + openvpn['intf'])

    # Check if interface instance has been removed
    if not conf.exists('interfaces openvpn ' + openvpn['intf']):
        openvpn['deleted'] = True
        return openvpn

    # Check if we belong to any bridge interface
    for bridge in conf.list_nodes('interfaces bridge'):
        for intf in conf.list_nodes('interfaces bridge {} member interface'.format(bridge)):
            if intf == openvpn['intf']:
                openvpn['bridge_member'].append(intf)

    # set configuration level
    conf.set_level('interfaces openvpn ' + openvpn['intf'])

    # retrieve authentication options - username
    if conf.exists('authentication username'):
        openvpn['auth_user'] = conf.return_value('authentication username')
        openvpn['auth'] = True

    # retrieve authentication options - username
    if conf.exists('authentication password'):
        openvpn['auth_pass'] = conf.return_value('authentication password')
        openvpn['auth'] = True

    # retrieve interface description
    if conf.exists('description'):
        openvpn['description'] = conf.return_value('description')

    # interface device-type
    if conf.exists('device-type'):
        openvpn['type'] = conf.return_value('device-type')

    # interface disabled
    if conf.exists('disabled'):
        openvpn['disabled'] = True

    # data encryption algorithm
    if conf.exists('encryption'):
        openvpn['encryption'] = conf.return_value('encryption')

    # hash algorithm
    if conf.exists('hash'):
        openvpn['hash'] = conf.return_value('hash')

    # Maximum number of keepalive packet failures
    if conf.exists('keep-alive failure-count') and conf.exists('keep-alive interval'):
        fail_count = conf.return_value('keep-alive failure-count')
        interval = conf.return_value('keep-alive interval')
        openvpn['ping_interval' ] = interval
        openvpn['ping_restart' ] = int(interval) * int(fail_count)

    # Local IP address of tunnel - even as it is a tag node - we can only work
    # on the first address
    if conf.exists('local-address'):
        openvpn['local_address'] = conf.list_nodes('local-address')[0]
        if conf.exists('local-address {} subnet-mask'.format(openvpn['local_address'])):
            openvpn['local_address_subnet'] = conf.return_value('local-address {} subnet-mask'.format(openvpn['local_address']))

    # Local IP address to accept connections
    if conf.exists('local-host'):
        openvpn['local_host'] = conf.return_value('local-host')

    # Local port number to accept connections
    if conf.exists('local-port'):
        openvpn['local_port'] = conf.return_value('local-port')

    # OpenVPN operation mode
    if conf.exists('mode'):
        mode = conf.return_value('mode')
        openvpn['mode'] = mode

    # Additional OpenVPN options
    if conf.exists('openvpn-option'):
        openvpn['options'] = conf.return_values('openvpn-option')

    # Do not close and reopen interface
    if conf.exists('persistent-tunnel'):
        openvpn['persistent_tunnel'] = True

    # Communication protocol
    if conf.exists('protocol'):
        openvpn['protocol'] = conf.return_value('protocol')

    # IP address of remote end of tunnel
    if conf.exists('remote-address'):
        openvpn['remote_address'] = conf.return_value('remote-address')

    # Remote host to connect to (dynamic if not set)
    if conf.exists('remote-host'):
        openvpn['remote_host'] = conf.return_values('remote-host')

    # Remote port number to connect to
    if conf.exists('remote-port'):
        openvpn['remote_port'] = conf.return_value('remote-port')

    # OpenVPN tunnel to be used as the default route
    # see https://openvpn.net/community-resources/reference-manual-for-openvpn-2-4/
    # redirect-gateway flags
    if conf.exists('replace-default-route'):
        openvpn['redirect_gateway'] = 'def1'

    if conf.exists('replace-default-route local'):
        openvpn['redirect_gateway'] = 'local def1'

    # Two Factor Authentication providers
    # currently limited to authy
    if conf.exists('2-factor-authentication authy api-key'):
        openvpn['server_2fa_authy_key'] = conf.return_value('2-factor-authentication authy api-key')

    # Authy users (must be email address)
    for user in conf.list_nodes('server 2-factor-authentication authy user'):
        # set configuration level
        conf.set_level('interfaces openvpn ' + openvpn['intf'] + ' 2-factor-authentication authy user ' + user)
        data = {
            'user': user,
            'country_code': '',
            'mobile_number': ''
        }

        # Country calling codes
        if conf.exists('country-calling-code'):
            data['country_code'] = conf.return_value('country-calling-code')

        # Mobile phone number
        if conf.exists('phone-number'):
            data['mobile_number'] = conf.return_value('phone-number')

        openvpn['server_2fa_authy'].append(data)

    # Topology for clients
    if conf.exists('server topology'):
        openvpn['server_topology'] = conf.return_value('server topology')

    # Server-mode subnet (from which client IPs are allocated)
    if conf.exists('server subnet'):
        network = conf.return_value('server subnet')
        tmp = IPv4Interface(network).with_netmask
        # convert the network in format: "192.0.2.0 255.255.255.0" for later use in template
        openvpn['server_subnet'] = tmp.replace(r'/', ' ')

    # Client-specific settings
    for client in conf.list_nodes('server client'):
        # set configuration level
        conf.set_level('interfaces openvpn ' + openvpn['intf'] + ' server client ' + client)
        data = {
            'name': client,
            'disabled': False,
            'ip': '',
            'push_route': [],
            'subnet': [],
            'remote_netmask': ''
        }

        # note: with "topology subnet", this is "<ip> <netmask>".
        #       with "topology p2p", this is "<ip> <our_ip>".
        if openvpn['server_topology'] == 'subnet':
            # we are only interested in the netmask portion of server_subnet
            data['remote_netmask'] = openvpn['server_subnet'][1]
        else:
            # we need the server subnet in format 192.0.2.0/255.255.255.0
            subnet = openvpn['server_subnet'].replace(' ', r'/')
            # get iterator over the usable hosts in the network
            tmp = ip_network(subnet).hosts()
            # OpenVPN always uses the subnets first available IP address
            data['remote_netmask'] = list(tmp)[0]

        # Option to disable client connection
        if conf.exists('disable'):
            data['disabled'] = True

        # IP address of the client
        if conf.exists('ip'):
            data['ip'] = conf.return_value('ip')

        # Route to be pushed to the client
        for network in conf.return_values('push-route'):
            tmp = IPv4Interface(network).with_netmask
            data['push_route'].append(tmp.replace(r'/', ' '))

        # Subnet belonging to the client
        for network in conf.return_values('subnet'):
            tmp = IPv4Interface(network).with_netmask
            data['subnet'].append(tmp.replace(r'/', ' '))

        # Append to global client list
        openvpn['client'].append(data)

    # re-set configuration level
    conf.set_level('interfaces openvpn ' + openvpn['intf'])

    # DNS suffix to be pushed to all clients
    if conf.exists('server domain-name'):
        openvpn['server_domain'] = conf.return_value('server domain-name')

    # Number of maximum client connections
    if conf.exists('server max-connections'):
        openvpn['server_max_conn'] = conf.return_value('server max-connections')

    # Domain Name Server (DNS)
    if conf.exists('server name-server'):
        openvpn['server_dns_nameserver'] = conf.return_values('server name-server')

    # Route to be pushed to all clients
    if conf.exists('server push-route'):
        network = conf.return_value('server push-route')
        tmp = IPv4Interface(network).with_netmask
        openvpn['server_push_route'] = tmp.replace(r'/', ' ')

    # Reject connections from clients that are not explicitly configured
    if conf.exists('server reject-unconfigured-clients'):
        openvpn['server_reject_unconfigured'] = True

    # File containing certificate for Certificate Authority (CA)
    if conf.exists('tls ca-cert-file'):
         openvpn['tls_ca_cert'] = conf.return_value('tls ca-cert-file')
         openvpn['tls'] = True

    # File containing certificate for this host
    if conf.exists('tls cert-file'):
         openvpn['tls_cert'] = conf.return_value('tls cert-file')
         openvpn['tls'] = True

    # File containing certificate revocation list (CRL) for this host
    if conf.exists('tls crl-file'):
         openvpn['tls_crl'] = conf.return_value('tls crl-file')
         openvpn['tls'] = True

    # File containing Diffie Hellman parameters (server only)
    if conf.exists('tls dh-file'):
         openvpn['tls_dh'] = conf.return_value('tls dh-file')
         openvpn['tls'] = True

    # File containing this host's private key
    if conf.exists('tls key-file'):
         openvpn['tls_key'] = conf.return_value('tls key-file')
         openvpn['tls'] = True

    # Role in TLS negotiation
    if conf.exists('tls role'):
         openvpn['tls_role'] = conf.return_value('tls role')
         openvpn['tls'] = True

    if conf.exists('shared-secret-key-file'):
        openvpn['shared_secret_file'] = conf.return_value('shared-secret-key-file')

    if conf.exists('use-lzo-compression'):
        openvpn['compress_lzo'] = True

    return openvpn

def verify(openvpn):
    if openvpn['deleted']:
        return None

    if not openvpn['mode']:
        raise ConfigError('Must specify OpenVPN operation mode')

    # Checks which need to be performed on interface rmeoval
    if openvpn['deleted']:
        # OpenVPN interface can not be deleted if it's still member of a bridge
        if openvpn['bridge_member']:
            raise ConfigError('Can not delete {} as it is a member interface of bridge {}!'.format(openvpn['intf'], bridge))

    #
    # OpenVPN client mode - VERIFY
    #
    if openvpn['mode'] == 'client':
        if openvpn['local_port']:
            raise ConfigError('Cannot specify "local-port" in client mode')

        if openvpn['local_host']:
            raise ConfigError('Cannot specify "local-host" in client mode')

        if openvpn['protocol'] == 'tcp-passive':
            raise ConfigError('Protocol "tcp-passive" is not valid in client mode')

        if not openvpn['remote_host']:
            raise ConfigError('Must specify "remote-host" in client mode')

        if openvpn['tls_dh']:
            raise ConfigError('Cannot specify "tls dh-file" in client mode')

    #
    # OpenVPN site-to-site - VERIFY
    #
    if openvpn['mode'] == 'site-to-site':
        if not (openvpn['local_address'] or openvpn['bridge_member']):
            raise ConfigError('Must specify "local-address" or "bridge member interface"')

        if not openvpn['remote_address']:
            raise ConfigError('Must specify "remote-address"')

        if openvpn['local_address'] == openvpn['local_host']:
            raise ConfigError('"local-address" cannot be the same as "local-host"')

        for host in openvpn['remote_host']:
            if host == openvpn['remote_address']:
                raise ConfigError('"remote-address" cannot be the same as "remote-host"')

        if openvpn['local_address'] == openvpn['remote_address']:
            raise ConfigError('"local-address" and "remote-address" cannot be the same')

        if openvpn['type'] == 'tap' and openvpn['local_address_subnet'] == '':
            raise ConfigError('Must specify "subnet-mask" for local-address')

    else:
        if openvpn['local_address'] or openvpn['remote_address']:
            raise ConfigError('Cannot specify "local-address" or "remote-address" in client-server mode')
        elif openvpn['bridge_member']:
            raise ConfigError('Cannot specify "local-address" or "remote-address" in bridge mode')

    #
    # OpenVPN server mode - VERIFY
    #
    if openvpn['mode'] == 'server':
        if openvpn['protocol'] == 'tcp-active':
            raise ConfigError('Protocol "tcp-active" is not valid in server mode')

        if openvpn['remote_port']:
            raise ConfigError('Cannot specify "remote-port" in server mode')

        if openvpn['remote_host']:
            raise ConfigError('Cannot specify "remote-host" in server mode')

        if openvpn['protocol'] == 'tcp-passive' and len(openvpn['remote_host']) > 1:
            raise ConfigError('Cannot specify more than 1 "remote-host" with "tcp-passive"')

        if not openvpn['tls_dh']:
            raise ConfigError('Must specify "tls dh-file" in server mode')

        if not openvpn['server_subnet']:
            if not openvpn['bridge_member']:
                raise ConfigError('Must specify "server subnet" option in server mode')

    else:
        # checks for both client and site-to-site go here
        if openvpn['server_reject_unconfigured']:
            raise ConfigError('reject-unconfigured-clients is only supported in OpenVPN server mode')

        if openvpn['server_topology']:
            raise ConfigError('The "topology" option is only valid in server mode')

        if (not openvpn['remote_host']) and openvpn['redirect_gateway']:
            raise ConfigError('Cannot set "replace-default-route" without "remote-host"')

    #
    # OpenVPN common verification section
    # not depending on any operation mode
    #

    # verify specified IP address is present on any interface on this system
    if openvpn['local_host']:
        if not is_addr_assigned(openvpn['local_host']):
            raise ConfigError('No interface on system with specified local-host IP address: {}'.format(openvpn['local_host']))

    # TCP active
    if openvpn['protocol'] == 'tcp-active':
        if openvpn['local_port']:
            raise ConfigError('Cannot specify "local-port" with "tcp-active"')

        if not openvpn['remote_host']:
            raise ConfigError('Must specify "remote-host" with "tcp-active"')

    # shared secret and TLS
    if not (openvpn['shared_secret_file'] or openvpn['tls']):
        raise ConfigError('Must specify one of "shared-secret-key-file" and "tls"')

    if openvpn['shared_secret_file'] and openvpn['tls']:
        raise ConfigError('Can only specify one of "shared-secret-key-file" and "tls"')

    if openvpn['mode'] in ['client', 'server']:
        if not openvpn['tls']:
            raise ConfigError('Must specify "tls" in client-server mode')

    #
    # TLS/encryption
    #
    if not checkCertHeader('-----BEGIN OpenVPN Static key V1-----', openvpn['shared_secret_file']):
        raise ConfigError('Specified shared-secret-key-file "{}" is not valid'.format(openvpn['shared_secret_file']))

    if openvpn['tls']:
        if not openvpn['tls_ca_cert']:
            raise ConfigError('Must specify "tls ca-cert-file"')

        if not (openvpn['mode'] == 'client' and openvpn['auth']):
            if not openvpn['tls_cert']:
                raise ConfigError('Must specify "tls cert-file"')

            if not openvpn['tls_key']:
                raise ConfigError('Must specify "tls key-file"')

        if not checkCertHeader('-----BEGIN CERTIFICATE-----', openvpn['tls_ca_cert']):
            raise ConfigError('Specified ca-cert-file "{}" is invalid'.format(openvpn['tls_ca_cert']))

        if not checkCertHeader('-----BEGIN CERTIFICATE-----', openvpn['tls_cert']):
            raise ConfigError('Specified cert-file "{}" is invalid'.format(openvpn['tls_cert']))

        if not checkCertHeader('-----BEGIN (?:RSA )?PRIVATE KEY-----', openvpn['tls_key']):
            raise ConfigError('Specified key-file "{}" is not valid'.format(openvpn['tls_key']))

        if not checkCertHeader('-----BEGIN X509 CRL-----', openvpn['tls_crl']):
            raise ConfigError('Specified crl-file "{} not valid'.format(openvpn['tls_crl']))

        if not checkCertHeader('-----BEGIN DH PARAMETERS-----', openvpn['tls_dh']):
            raise ConfigError('Specified dh-file "{}" is not valid'.format(openvpn['tls_dh']))

        if openvpn['tls_role']:
            if openvpn['mode'] in ['client', 'server']:
                raise ConfigError('Cannot specify "tls role" in client-server mode')

            if openvpn['tls_role'] == 'active':
                if openvpn['protocol'] == 'tcp-passive':
                    raise ConfigError('Cannot specify "tcp-passive" when "tls role" is "active"')

                if openvpn['tls_dh']:
                    raise ConfigError('Cannot specify "tls dh-file" when "tls role" is "active"')

            elif openvpn['tls_role'] == 'passive':
                if openvpn['protocol'] == 'tcp-active':
                    raise ConfigError('Cannot specify "tcp-active" when "tls role" is "passive"')

                if not openvpn['tls_dh']:
                    raise ConfigError('Must specify "tls dh-file" when "tls role" is "passive"')

    #
    # Auth user/pass
    #
    if openvpn['auth']:
        if not openvpn['auth_user']:
            raise ConfigError('Username for authentication is missing')

        if not openvpn['auth_pass']:
            raise ConfigError('Password for authentication is missing')

    #
    # Client
    #
    subnet = openvpn['server_subnet'].replace(' ', '/')
    for client in openvpn['client']:
        if not ip_address(client['ip']) in ip_network(subnet):
            raise ConfigError('Client IP "{}" not in server subnet "{}'.format(client['ip'], subnet))



    return None

def generate(openvpn):
    if openvpn['deleted']:
        return None

    interface = openvpn['intf']
    directory = os.path.dirname(get_config_name(interface))

    # create config directory on demand
    openvpn_mkdir(directory)
    # create status directory on demand
    openvpn_mkdir(directory + '/status')
    # create client config dir on demand
    openvpn_mkdir(directory + '/ccd')
    # crete client config dir per interface on demand
    openvpn_mkdir(directory + '/ccd/' + interface)

    # Fix file permissons for keys
    fixup_permission(openvpn['shared_secret_file'])
    fixup_permission(openvpn['tls_key'])

    # Generate User/Password authentication file
    if openvpn['auth']:
        auth_file = '/tmp/openvpn-{}-pw'.format(interface)
        with open(auth_file, 'w') as f:
            f.write('{}\n{}'.format(openvpn['auth_user'], openvpn['auth_pass']))

        fixup_permission(auth_file)

    # get numeric uid/gid
    uid = pwd.getpwnam(user).pw_uid
    gid = grp.getgrnam(group).gr_gid

    # Generate client specific configuration
    for client in openvpn['client']:
        client_file = directory + '/ccd/' + interface + '/' + client['name']
        tmpl = jinja2.Template(client_tmpl)
        client_text = tmpl.render(client)
        with open(client_file, 'w') as f:
            f.write(client_text)
        os.chown(client_file, uid, gid)

    tmpl = jinja2.Template(config_tmpl)
    config_text = tmpl.render(openvpn)
    with open(get_config_name(interface), 'w') as f:
        f.write(config_text)
    os.chown(get_config_name(interface), uid, gid)

    return None


def apply(openvpn):
    interface = openvpn['intf']

    pid = 0
    pidfile = '/var/run/openvpn/{}.pid'.format(interface)
    if os.path.isfile(pidfile):
        pid = 0
        with open(pidfile, 'r') as f:
            pid = int(f.read())

    # If tunnel interface has been deleted - stop service
    if openvpn['deleted']:
        directory = os.path.dirname(get_config_name(interface))

        # we only need to stop the demon if it's running
        # daemon could have died or killed by someone
        if psutil.pid_exists(pid):
            cmd  = 'start-stop-daemon --stop --quiet'
            cmd += ' --pidfile ' + pidfile
            subprocess_cmd(cmd)

        # cleanup old PID file
        if os.path.isfile(pidfile):
            os.remove(pidfile)

        # cleanup old configuration file
        if os.path.isfile(get_config_name(interface)):
            os.remove(get_config_name(interface))

        # cleanup client config dir
        if os.path.isdir(directory + '/ccd/' + interface):
            try:
                os.remove(directory + '/ccd/' + interface + '/*')
            except:
                pass

        return None

    # Send SIGUSR1 to the process instead of creating a new process
    if psutil.pid_exists(pid):
        os.kill(pid, SIGUSR1)
        return None

    # No matching OpenVPN process running - maybe it got killed or none
    # existed - nevertheless, spawn new OpenVPN process
    cmd  = 'start-stop-daemon --start --quiet'
    cmd += ' --pidfile ' + pidfile
    cmd += ' --exec /usr/sbin/openvpn'
    # now pass arguments to openvpn binary
    cmd += ' --'
    cmd += ' --config ' + get_config_name(interface)

    # execute assembled command
    subprocess_cmd(cmd)

    return None

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