aboutsummaryrefslogtreecommitdiff
path: root/util.py
blob: 987fd926c269ea7ae4e21a9d6c0750ce40a5abc5 (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
import logging
import time
from errors import CriticalError, InputError, ConfigError, SocketError

class VlanUtil:
    """VLANd utility functions"""

    def get_switch_driver(self, switch_name, config):
        logging.debug("Trying to find a driver for %s" % switch_name)
        driver = config.switches[switch_name].driver
        logging.debug("Driver: %s" % driver)
        module = __import__("drivers.%s" % driver, fromlist=[driver])
        class_ = getattr(module, driver)
        return class_(switch_name)

    def probe_switches(self, state):
        config = state.config
        ret = {}
        for switch_name in sorted(config.switches):
            print "Found switch %s:" % (switch_name)
            print "  Probing..."

            s = self.get_switch_driver(switch_name, config)
            s.switch_connect(config.switches[switch_name].username,
                             config.switches[switch_name].password,
                             config.switches[switch_name].enable_password)
            ret[switch_name] = 'Found %d ports' % len(s.switch_get_port_names())
            s.switch_disconnect()
            del(s)
        return ret

    # Simple helper wrapper for all the read-only database queries
    def perform_db_query(self, state, command, data):
        print 'perform_db_query'
        print command
        print data
        ret = {}
        db = state.db
        try:
            if command == 'db.all_switches':
                ret = db.all_switches()
            elif command == 'db.all_ports':
                ret = db.all_ports()
            elif command == 'db.all_vlans':
                ret = db.all_vlans()
            elif command == 'db.get_switch_by_id':
                ret = db.get_switch_by_id(data['switch_id'])
            elif command == 'db.get_switch_id_by_name':
                ret = db.get_switch_id_by_name(data['name'])
            elif command == 'db.get_switch_name_by_id':
                ret = db.get_switch_name_by_id(data['switch_id'])
            elif command == 'db.get_port_by_id':
                ret = db.get_port_by_id(data['port_id'])
            elif command == 'db.get_ports_by_switch':
                ret = db.get_ports_by_switch(data['switch_id'])
            elif command == 'db.get_port_by_switch_and_name':
                ret = db.get_port_by_switch_and_name(data['switch_id'], data['name'])
            elif command == 'db.get_current_vlan_id_by_port':
                ret = db.get_current_vlan_id_by_port(data['port_id'])
            elif command == 'db.get_base_vlan_id_by_port':
                ret = db.get_base_vlan_id_by_port(data['port_id'])
            elif command == 'db.get_ports_by_current_vlan':
                ret = db.get_ports_by_current_vlan(data['vlan_id'])
            elif command == 'db.get_ports_by_base_vlan':
                ret = db.get_ports_by_base_vlan(data['vlan_id'])
            elif command == 'db.get_vlan_by_id':
                ret = db.get_vlan_by_id(data['vlan_id'])
            elif command == 'db.get_vlan_id_by_name':
                ret = db.get_vlan_id_by_name(data['name'])
            elif command == 'db.get_vlan_id_by_tag':
                ret = db.get_vlan_id_by_tag(data['tag'])
            elif command == 'db.get_vlan_name_by_id':
                ret = db.get_vlan_name_by_id(data['vlan_id'])
            else:
                raise InputError("Unknown db_query command \"%s\"" % command)

        except InputError:
            raise

        except:
            raise InputError("Invalid input in query")

        return ret

    # Simple helper wrapper for all the read-only daemon state queries
    def perform_daemon_query(self, state, command, data):
        print 'perform_daemon_query'
        print command
        print data
        ret = {}
        try:
            if command == 'daemon.status':
                # data ignored
                ret['running'] = 'ok'
            elif command == 'daemon.version':
                # data ignored
                ret['version'] = state.version
            elif command == 'daemon.statistics':
                ret['uptime'] = time.time() - state.starttime
            elif command == 'daemon.probe_switches':
                ret = self.probe_switches(state)
            else:
                raise InputError("Unknown daemon_query command \"%s\"" % command)

        except InputError:
            raise

        except:
            raise InputError("Invalid input in query")

        return ret

    # Helper wrapper for API functions modifying database state only
    def perform_db_update(self, state, command, data):
        print 'perform_db_update'
        print command
        print data
        ret = {}
        db = state.db
        try:
            if command == 'db.create_switch':
                ret = db.create_switch(data['name'])
            elif command == 'db.create_port':
                ret = db.create_port(data['switch_id'], data['name'],
                                     state.default_vlan_id,
                                     state.default_vlan_id)
            elif command == 'db.delete_switch':
                ret = db.delete_switch(data['switch_id'])
            elif command == 'db.delete_port':
                ret = db.delete_port(data['port_id'])
            elif command == 'db.set_port_is_locked':
                ret = db.set_port_is_locked(data['port_id'], data['is_locked'])
            elif command == 'db.set_base_vlan':
                ret = db.set_base_vlan(data['port_id'], data['base_vlan_id'])
            else:
                raise InputError("Unknown db_update command \"%s\"" % command)

        except InputError:
            raise

        except:
            raise InputError("Invalid input in query")

        return ret

    # Helper wrapper for API functions that modify both database state
    # and on-switch VLAN state
    def perform_vlan_update(self, state, command, data):
        print 'perform_vlan_update'
        print command
        print data
        ret = {}

        try:
            # All of these are complex commands, so call helpers
            # rather than inline the code here
            if command == 'api.create_vlan':
                ret = self.create_vlan(state, data['name'], int(data['tag']), data['is_base_vlan'])
            elif command == 'api.delete_vlan':
                ret = self.delete_vlan(state, int(data['vlan_id']))
            elif command == 'api.set_port_mode':
                ret = self.set_port_mode(state, int(data['port_id']), data['mode'])
            elif command == 'api.set_current_vlan':
                ret = self.set_current_vlan(state, int(data['port_id']), int(data['vlan_id']))
            elif command == 'api.restore_base_vlan':
                ret = self.restore_base_vlan(state, int(data['port_id']))
            elif command == 'api.auto_import_switch':
                ret = self.auto_import_switch(state, data['switch'])
            else:
                raise InputError("Unknown query command \"%s\"" % command)

        except InputError as e:
            print 'got error %s' % e
            raise

        except:
            raise InputError("Invalid input in query")

        return ret


    # Complex call
    # 1. create the VLAN in the DB
    # 2. Iterate through all switches:
    #    a. Create the VLAN
    #    b. Add the VLAN to all trunk ports (if needed)
    # 3. If all went OK, save config on all the switches
    #
    # The VLAN may already exist on some of the switches, that's
    # fine. If things fail, we attempt to roll back by rebooting
    # switches then removing the VLAN in the DB.
    def create_vlan(self, state, name, tag, is_base_vlan):

        print 'create_vlan'
        db = state.db
        config = state.config

        # 1. Database record first
        try:
            print 'Adding DB record first: name %s, tag %d, is_base_vlan %d' % (name, tag, is_base_vlan)
            vlan_id = db.create_vlan(name, tag, is_base_vlan)
            print 'Added VLAN tag %d, name %s to the database, created VLAN ID %d' % (tag, name, vlan_id)
        except InputError:
            print 'DB creation failed'
            raise

        # Keep track of which switches we've configured, for later use
        switches_done = []

        # 2. Now the switches
        try:
            for switch in db.all_switches():
                trunk_ports = []
                switch_name = switch.name
                try:
                    print 'Adding new VLAN to switch %s' % switch_name
                    # Get the right driver
                    s = self.get_switch_driver(switch_name, config)
                    s.switch_connect(config.switches[switch_name].username,
                                     config.switches[switch_name].password,
                                     config.switches[switch_name].enable_password)

                    # Mark this switch as one we've touched, for
                    # either config saving or rollback below
                    switches_done.append(switch_name)

                    # 2a. Create the VLAN on the switch
                    s.vlan_create(tag)
                    s.vlan_set_name(tag, name)
                    print 'Added VLAN tag %d, name %s to switch %s' % (tag, name, switch_name)

                    # 2b. Do we need to worry about trunk ports on this switch?
                    if 'TrunkWildCardVlans' in s.switch_get_capabilities():
                        print 'This switch does not need special trunk port handling'
                    else:
                        print 'This switch needs special trunk port handling'
                        trunk_ports = db.get_trunk_port_names_by_switch(switch.switch_id)
                        if trunk_ports is None:
                            print "But it has no trunk ports defined"
                            trunk_ports = []
                        else:
                            print 'Found %d trunk_ports that need adjusting' % len(trunk_ports)

                    # Modify any trunk ports as needed
                    for port in trunk_ports:
                        print 'Added VLAN tag %d, name %s to switch %s' % (tag, name, switch_name)
                        s.port_add_trunk_to_vlan(port, tag)

                    # And now we're done with this switch
                    s.switch_disconnect()
                    del s

                except IOError:
                    raise
        
        except IOError:
            # Bugger. Looks like one of the switch calls above
            # failed. To undo the changes safely, we'll need to reset
            # all the switches we managed to configure. This could
            # take some time!
            for switch_name in switches_done:
                s = self.get_switch_driver(switch_name, config)
                s.switch_connect(config.switches[switch_name].username,
                                 config.switches[switch_name].password,
                                 config.switches[switch_name].enable_password)
                s.switch_restart() # Will implicitly also close the connection
                del s

            # Undo the database change
            print 'Switch access failed. Deleting the new VLAN entry in the database'
            db.delete_vlan(vlan_id)
            raise

        # If we've got this far, things were successful. Save config
        # on all the switches so it will persist across reboots
        for switch_name in switches_done:
            s = self.get_switch_driver(switch_name, config)
            s.switch_connect(config.switches[switch_name].username,
                             config.switches[switch_name].password,
                             config.switches[switch_name].enable_password)
            s.switch_save_running_config()
            s.switch_disconnect()
            del s

        return vlan_id # If we're successful

    # Complex call
    # 1. Check in the DB if there are any ports on the VLAN. Bail if so
    # 2. Iterate through all switches:
    #    a. Remove the VLAN from all trunk ports (if needed)
    #    b. Remove the VLAN
    # 3. If all went OK, save config on the switches
    # 4. Remove the VLAN in the DB
    #
    # If things fail, we attempt to roll back by rebooting switches.
    def delete_vlan(self, state, vlan_id):

        print 'delete_vlan'
        db = state.db
        config = state.config

        # 1. Check for database records first
        print 'Checking for ports using VLAN ID %d' % vlan_id
        vlan = db.get_vlan_by_id(vlan_id)
        if vlan is None:
            raise InputError("VLAN ID %d does not exist" % vlan_id)
        vlan_tag = vlan.tag
        ports = db.get_ports_by_current_vlan(vlan_id)
        if ports is not None:
            raise InputError("Cannot delete VLAN ID %d when it still has %d ports" %
                             (vlan_id, len(ports)))
        ports = db.get_ports_by_base_vlan(vlan_id)
        if ports is not None:
            raise InputError("Cannot delete VLAN ID %d when it still has %d ports" %
                             (vlan_id, len(ports)))

        # Keep track of which switches we've configured, for later use
        switches_done = []

        # 2. Now the switches
        try:
            for switch in db.all_switches():
                switch_name = switch.name
                trunk_ports = []
                try:
                    # Get the right driver
                    s = self.get_switch_driver(switch_name, config)
                    s.switch_connect(config.switches[switch_name].username,
                                     config.switches[switch_name].password,
                                     config.switches[switch_name].enable_password)

                    # Mark this switch as one we've touched, for
                    # either config saving or rollback below
                    switches_done.append(switch_name)

                    # 2a. Do we need to worry about trunk ports on this switch?
                    if 'TrunkWildCardVlans' in s.switch_get_capabilities():
                        print 'This switch does not need special trunk port handling'
                    else:
                        print 'This switch needs special trunk port handling'
                        trunk_ports = db.get_trunk_port_names_by_switch(switch.switch_id)
                        if trunk_ports is None:
                            print "But it has no trunk ports defined"
                            trunk_ports = []
                        else:
                            print 'Found %d trunk_ports that need adjusting' % len(trunk_ports)

                    # Modify any trunk ports as needed
                    for port in trunk_ports:
                        s.port_remove_trunk_from_vlan(port, vlan_tag)
                        print 'Removed VLAN tag %d from switch %s port %s' % (vlan_tag, switch_name, port)

                    # 2b. Remove the VLAN from the switch
                    print 'Removing VLAN tag %d from switch %s' % (vlan_tag, switch_name)
                    s.vlan_destroy(vlan_tag)
                    print 'Removed VLAN tag %d from switch %s' % (vlan_tag, switch_name)

                    # And now we're done with this switch
                    s.switch_disconnect()
                    del s

                except IOError:
                    raise

        except IOError:
            # Bugger. Looks like one of the switch calls above
            # failed. To undo the changes safely, we'll need to reset
            # all the switches we managed to configure. This could
            # take some time!
            for switch_name in switches_done:
                s = self.get_switch_driver(switch_name, config)
                s.switch_connect(config.switches[switch_name].username,
                                 config.switches[switch_name].password,
                                 config.switches[switch_name].enable_password)
                s.switch_restart() # Will implicitly also close the connection
                del s
                raise

        # 3. If we've got this far, things were successful. Save
        # config on all the switches so it will persist across reboots
        for switch_name in switches_done:
            s = self.get_switch_driver(switch_name, config)
            s.switch_connect(config.switches[switch_name].username,
                             config.switches[switch_name].password,
                             config.switches[switch_name].enable_password)
            s.switch_save_running_config()
            s.switch_disconnect()
            del s

        # 4. Finally, remove the VLAN in the DB
        try:
            print 'Removing DB record: VLAN ID %d' % vlan_id
            vlan_id = db.delete_vlan(vlan_id)
            print 'Removed VLAN ID %d from the database OK' % vlan_id
        except InputError:
            print 'DB deletion failed'
            raise

        return vlan_id # If we're successful

    # Complex call, depends on existing state a lot
    # 1. Check validity of inputs
    # 2. Switch mode and other config on the port.
    #    a. If switching trunk->access, remove all trunk VLANs from it
    #       (if needed) and switch back to the base VLAN for the
    #       port. Next, switch to access mode.
    #    b. If switching access->trunk, switch back to the base VLAN
    #       for the port. Next, switch mode. Then add all trunk VLANs
    #       to it (if needed)
    # 3. If all went OK, save config on the switch
    # 4. Change details of the port in the DB
    #
    # If things fail, we attempt to roll back by rebooting the switch
    def set_port_mode(self, state, port_id, mode):

        print 'set_port_mode'
        db = state.db
        config = state.config

        # 1. Sanity-check inputs
        if mode is not 'access' and mode is not 'trunk':
            raise InputError("Port mode %s is not a valid option: try 'access' or 'trunk" % mode)
        port = db.get_port_by_id(port_id)
        if port is None:
            raise InputError("Port ID %d does not exist" % port_id)
        if mode == 'trunk' and port.is_trunk:
            raise InputError("Port ID %d is already in trunk mode")
        if mode == 'access' and not port.is_trunk:
            raise InputError("Port ID %d is already in access mode")
        base_vlan_tag = db.get_vlan_tag_by_id(port.base_vlan_id)

        # Get the right driver
        switch_name = db.get_switch_name_by_id(port.switch_id)
        s = self.get_switch_driver(switch_name, config)

        # 2. Now start configuring the switch
        try:
            s.switch_connect(config.switches[switch_name].username,
                             config.switches[switch_name].password,
                             config.switches[switch_name].enable_password)
        except:
            print 'Failed to talk to switch %s!' % switch_name
            raise

        try:
            if port.is_trunk:
                # 2a. We're going from a trunk port to an access port
                if 'TrunkWildCardVlans' in s.switch_get_capabilities():
                    print 'This switch does not need special trunk port handling'
                else:
                    print 'This switch needs special trunk port handling'
                    vlans = s.port_get_trunk_vlan_list(port.name)
                    if vlans is None:
                        print "But it has no VLANs defined on port %s" % port.name
                        vlans = []
                    else:
                        print 'Found %d vlans that need dropping on port %s' % (len(vlans), port.name)

                    for vlan in vlans:
                        s.port_remove_trunk_from_vlan(port.name, vlan)
                    s.port_add_trunk_to_vlan(port.name, base_vlan_tag)
                    s.port_set_mode(port.name, "access")

            else:
                # 2b. We're going from an access port to a trunk port
                s.port_set_access_vlan(port.name, base_vlan_tag)
                s.port_set_mode(port.name, "trunk")
                if 'TrunkWildCardVlans' in s.switch_get_capabilities():
                    print 'This switch does not need special trunk port handling'
                else:
                    vlans = db.all_vlans()
                    for vlan in vlans:
                        s.port_add_trunk_to_vlan(port.name, vlan.tag)

        except IOError:
            # Bugger. Looks like one of the switch calls above
            # failed. To undo the changes safely, we'll need to reset
            # all the config on this switch
            s.switch_restart() # Will implicitly also close the connection
            del s
            raise

        # 3. All seems to have worked so far!
        s.switch_save_running_config()
        s.switch_disconnect()
        del s

        # 4. And update the DB
        db.set_port_mode(port_id, mode)

        return port_id # If we're successful

    # Complex call, updating both DB and switch state
    # 1. Check validity of inputs
    # 2. Update the port config on the switch
    # 3. If all went OK, save config on the switch
    # 4. Change details of the port in the DB
    #
    # If things fail, we attempt to roll back by rebooting the switch
    def set_current_vlan(self, state, port_id, vlan_id):

        print 'set_current_vlan'
        db = state.db
        config = state.config

        # 1. Sanity checks!
        port = db.get_port_by_id(port_id)
        if port is None:
            raise InputError("Port ID %d does not exist" % port_id)
        if port.is_trunk:
            raise InputError("Port ID %d is not an access port" % port_id)
        if port.is_locked:
            raise InputError("Port ID %d is locked" % port_id)

        vlan = db.get_vlan_by_id(vlan_id)
        if vlan is None:
            raise InputError("VLAN ID %d does not exist" % vlan_id)

        # Get the right driver
        switch_name = db.get_switch_name_by_id(port.switch_id)
        s = self.get_switch_driver(switch_name, config)

        # 2. Now start configuring the switch
        try:
            s.switch_connect(config.switches[switch_name].username,
                             config.switches[switch_name].password,
                             config.switches[switch_name].enable_password)
        except:
            print 'Failed to talk to switch %s!' % switch_name
            raise

        try:
            s.port_set_access_vlan(port.name, vlan.tag)
        except IOError:
            # Bugger. Looks like one of the switch calls above
            # failed. To undo the changes safely, we'll need to reset
            # all the config on this switch
            s.switch_restart() # Will implicitly also close the connection
            del s
            raise

        # 3. All seems to have worked so far!
        s.switch_save_running_config()
        s.switch_disconnect()
        del s

        # 4. And update the DB
        db.set_current_vlan(port_id, vlan_id)

        return port_id # If we're successful

    # Complex call, updating both DB and switch state
    # 1. Check validity of input
    # 2. Update the port config on the switch
    # 3. If all went OK, save config on the switch
    # 4. Change details of the port in the DB
    #
    # If things fail, we attempt to roll back by rebooting the switch
    def restore_base_vlan(self, state, port_id):

        print 'restore_base_vlan'
        db = state.db
        config = state.config

        # 1. Sanity checks!
        port = db.get_port_by_id(port_id)
        if port is None:
            raise InputError("Port ID %d does not exist" % port_id)
        if port.is_trunk:
            raise InputError("Port ID %d is not an access port" % port_id)
        if port.is_locked:
            raise InputError("Port ID %d is locked" % port_id)

        # Bail out early if we're *already* on the base VLAN. This is
        # not an error
        if port.current_vlan_id == port.base_vlan_id:
            return port_id

        vlan = db.get_vlan_by_id(port.base_vlan_id)

        # Get the right driver
        switch_name = db.get_switch_name_by_id(port.switch_id)
        s = self.get_switch_driver(switch_name, config)

        # 2. Now start configuring the switch
        try:
            s.switch_connect(config.switches[switch_name].username,
                             config.switches[switch_name].password,
                             config.switches[switch_name].enable_password)
        except:
            print 'Failed to talk to switch %s!' % switch_name
            raise

        try:
            s.port_set_access_vlan(port.name, vlan.tag)
        except IOError:
            # Bugger. Looks like one of the switch calls above
            # failed. To undo the changes safely, we'll need to reset
            # all the config on this switch
            s.switch_restart() # Will implicitly also close the connection
            del s
            raise

        # 3. All seems to have worked so far!
        s.switch_save_running_config()
        s.switch_disconnect()
        del s

        # 4. And update the DB
        db.set_current_vlan(port_id, port.base_vlan_id)

        return port_id # If we're successful

    # Complex call, updating both DB and switch state
    # * Check validity of input
    # * Read all the config from the switch (switch, ports, VLANs)
    # * Create initial DB entries to match each of those
    # * Merge VLANs across all switches
    # * Set up ports appropriately
    #
    def auto_import_switch(self, state, switch_name):

        print 'auto_import_switch'
        db = state.db
        config = state.config

        # 1. Sanity checks!
        switch_id = db.get_switch_id_by_name(switch_name)
        if switch_id is not None:
            raise InputError("Switch name %s already exists in the DB (ID %d)" % (switch_name, switch_id))

        if not switch_name in config.switches:
            raise InputError("Switch name %s not defined in config" % switch_name)

        print 'args look ok'

        # 2. Now start reading config from the switch
        try:
            s = self.get_switch_driver(switch_name, config)
            s.switch_connect(config.switches[switch_name].username,
                             config.switches[switch_name].password,
                             config.switches[switch_name].enable_password)
        except:
            print 'Failed to talk to switch %s!' % switch_name
            raise

        # DON'T create the switch record in the DB first - we'll want
        # to create VLANs on *other* switches, and it's easier to do
        # that before we've added our new switch

        new_vlan_tags = []

        # Grab the VLANs defined on this switch
        vlan_tags = s.vlan_get_list()

        print '  found %d vlans on the switch' % len(vlan_tags)

        for vlan_tag in vlan_tags:
            vlan_name = s.vlan_get_name(vlan_tag)

            # If a VLAN is already in the database, then that's easy -
            # we can just ignore it. However, we have to check that
            # there is not a different name for the existing VLAN tag
            # - bail out if so... UNLESS we're looking at the default
            # VLAN
            #
            # If this VLAN tag is not already in the DB, we'll need to
            # add it there and to all the other switches (and their
            # trunk ports!) too.
            vlan_id = db.get_vlan_id_by_tag(vlan_tag)
            if vlan_id is not state.default_vlan_id:
                if vlan_id is not None:
                    vlan_db_name = db.get_vlan_name_by_id(vlan_id)
                    if vlan_name != vlan_db_name:
                        raise InputError("Can't add VLAN tag %d (name %s) for this switch - VLAN tag %d already exists in the database, but with a different name (%s)" % (vlan_tag, vlan_name, vlan_tag, vlan_db_name))

                else:
                    # OK, we'll need to set up the new VLAN now. It can't
                    # be a base VLAN - switches don't have such a concept!
                    # Rather than create individually here, add to a
                    # list. *Only* once we've worked through all the
                    # switch's VLANs successfully (checking for existing
                    # records and possible clashes!) should we start
                    # committing changes
                    new_vlan_tags.append(vlan_tag)

        # Now create the VLAN DB entries
        for vlan_tag in new_vlan_tags:
            vlan_name = s.vlan_get_name(vlan_tag)
            vlan_id = self.create_vlan(state, vlan_name, vlan_tag, False)

        # *Now* add this switch itself to the database, after we've
        # worked on all the other switches
        switch_id = db.create_switch(switch_name)

        # And now the ports
        trunk_ports = []
        ports = s.switch_get_port_names()
        print '  found %d ports on the switch' % len(ports)
        for port_name in ports:
            print '  trying to import port %s' % port_name
            port_id = None
            port_mode = s.port_get_mode(port_name)
            if port_mode == 'access':
                # Access ports are easy - just create the port, and
                # set both the current and base VLANs to the current
                # VLAN on the switch. We'll end up changing this after
                # import if needed.
                port_vlan = s.port_get_access_vlan(port_name)
                port_id = db.create_port(switch_id, port_name, port_vlan, port_vlan)
                print '    access port, VLAN %d' % int(port_vlan)
                # Nothing further needed
            elif port_mode == 'trunk':
                print '    trunk port'
                # Trunk ports are a little more involved. First,
                # create the port in the DB, setting the VLANs to the
                # first VLAN found on the trunk port. This will *also*
                # be in access mode by default, and unlocked.
                port_vlans = s.port_get_trunk_vlan_list(port_name)
                print '    trunk port has VLANs:'
                print port_vlans
                if port_vlans is None or 'ALL' in port_vlans:
                    port_vlans = (state.default_vlan_id,) # easy for our purposes
                port_id = db.create_port(switch_id, port_name,
                                         port_vlans[0], port_vlans[0])
                # Append to a list of trunk ports that we will need to
                # modify once we're done
                trunk_ports.append(port_id)
            else:
                raise CriticalError("Unrecognised port port mode %s???" % port_mode)

            print "  Added port %s, got port ID %d" % (port_name, port_id)

        # Now, on each trunk port on the switch, we need to add all
        # the VLANs already configured across our system
        if not 'TrunkWildCardVlans' in s.switch_get_capabilities():
            for port_id in trunk_ports:
                port = db.get_port_by_id(port_id)
                db.set_port_mode(port_id, "trunk")
                
                for vlan in db.all_vlans():
                    if vlan.vlan_id is not state.default_vlan_id:
                        print "Adding allowed VLAN tag %d to trunk port %s" % (vlan.tag, port.name)
                        s.port_add_trunk_to_vlan(port.name, vlan.tag)


        # Done with this switch \o/
        s.switch_save_running_config()
        s.switch_disconnect()
        del s

        ret = {}
        ret['switch_id'] = switch_id
        ret['num_ports_added'] = len(ports)
        ret['num_vlans_added'] = len(new_vlan_tags)
        return ret # If we're successful