summaryrefslogtreecommitdiff
path: root/source4/nbt_server/wins/winsserver.c
blob: 399530b4cf75a7eda65b7dc72ef7eab458a88c8b (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
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
/* 
   Unix SMB/CIFS implementation.

   core wins server handling

   Copyright (C) Andrew Tridgell	2005
   Copyright (C) Stefan Metzmacher	2005
      
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.
   
   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/>.
*/

#include "includes.h"
#include "nbt_server/nbt_server.h"
#include "nbt_server/wins/winsdb.h"
#include "nbt_server/wins/winsserver.h"
#include "librpc/gen_ndr/ndr_nbt.h"
#include "system/time.h"
#include "libcli/composite/composite.h"
#include "smbd/service_task.h"
#include "system/network.h"
#include "lib/socket/socket.h"
#include "lib/socket/netif.h"
#include "lib/ldb/include/ldb.h"
#include "param/param.h"
#include "libcli/resolve/resolve.h"

/*
  work out the ttl we will use given a client requested ttl
*/
uint32_t wins_server_ttl(struct wins_server *winssrv, uint32_t ttl)
{
	ttl = MIN(ttl, winssrv->config.max_renew_interval);
	ttl = MAX(ttl, winssrv->config.min_renew_interval);
	return ttl;
}

static enum wrepl_name_type wrepl_type(uint16_t nb_flags, struct nbt_name *name, bool mhomed)
{
	/* this copes with the nasty hack that is the type 0x1c name */
	if (name->type == NBT_NAME_LOGON) {
		return WREPL_TYPE_SGROUP;
	}
	if (nb_flags & NBT_NM_GROUP) {
		return WREPL_TYPE_GROUP;
	}
	if (mhomed) {
		return WREPL_TYPE_MHOMED;
	}
	return WREPL_TYPE_UNIQUE;
}

/*
  register a new name with WINS
*/
static uint8_t wins_register_new(struct nbt_name_socket *nbtsock, 
				 struct nbt_name_packet *packet, 
				 const struct socket_address *src,
				 enum wrepl_name_type type)
{
	struct nbtd_interface *iface = talloc_get_type(nbtsock->incoming.private_data,
						       struct nbtd_interface);
	struct wins_server *winssrv = iface->nbtsrv->winssrv;
	struct nbt_name *name = &packet->questions[0].name;
	uint32_t ttl = wins_server_ttl(winssrv, packet->additional[0].ttl);
	uint16_t nb_flags = packet->additional[0].rdata.netbios.addresses[0].nb_flags;
	const char *address = packet->additional[0].rdata.netbios.addresses[0].ipaddr;
	struct winsdb_record rec;
	enum wrepl_name_node node;

#define WREPL_NODE_NBT_FLAGS(nb_flags) \
	((nb_flags & NBT_NM_OWNER_TYPE)>>13)

	node	= WREPL_NODE_NBT_FLAGS(nb_flags);

	rec.name		= name;
	rec.type		= type;
	rec.state		= WREPL_STATE_ACTIVE;
	rec.node		= node;
	rec.is_static		= false;
	rec.expire_time		= time(NULL) + ttl;
	rec.version		= 0; /* will be allocated later */
	rec.wins_owner		= NULL; /* will be set later */
	rec.registered_by	= src->addr;
	rec.addresses		= winsdb_addr_list_make(packet);
	if (rec.addresses == NULL) return NBT_RCODE_SVR;

	rec.addresses     = winsdb_addr_list_add(winssrv->wins_db,
						 &rec, rec.addresses,
						 address,
						 winssrv->wins_db->local_owner,
						 rec.expire_time,
						 true);
	if (rec.addresses == NULL) return NBT_RCODE_SVR;

	DEBUG(4,("WINS: accepted registration of %s with address %s\n",
		 nbt_name_string(packet, name), rec.addresses[0]->address));
	
	return winsdb_add(winssrv->wins_db, &rec, WINSDB_FLAG_ALLOC_VERSION | WINSDB_FLAG_TAKE_OWNERSHIP);
}


/*
  update the ttl on an existing record
*/
static uint8_t wins_update_ttl(struct nbt_name_socket *nbtsock, 
			       struct nbt_name_packet *packet, 
			       struct winsdb_record *rec,
			       struct winsdb_addr *winsdb_addr,
			       const struct socket_address *src)
{
	struct nbtd_interface *iface = talloc_get_type(nbtsock->incoming.private_data,
						       struct nbtd_interface);
	struct wins_server *winssrv = iface->nbtsrv->winssrv;
	uint32_t ttl = wins_server_ttl(winssrv, packet->additional[0].ttl);
	const char *address = packet->additional[0].rdata.netbios.addresses[0].ipaddr;
	uint32_t modify_flags = 0;

	rec->expire_time   = time(NULL) + ttl;
	rec->registered_by = src->addr;

	if (winsdb_addr) {
		rec->addresses = winsdb_addr_list_add(winssrv->wins_db,
						      rec, rec->addresses,
						      winsdb_addr->address,
						      winssrv->wins_db->local_owner,
						      rec->expire_time,
						      true);
		if (rec->addresses == NULL) return NBT_RCODE_SVR;
	}

	if (strcmp(winssrv->wins_db->local_owner, rec->wins_owner) != 0) {
		modify_flags = WINSDB_FLAG_ALLOC_VERSION | WINSDB_FLAG_TAKE_OWNERSHIP;
	}

	DEBUG(5,("WINS: refreshed registration of %s at %s\n",
		 nbt_name_string(packet, rec->name), address));
	
	return winsdb_modify(winssrv->wins_db, rec, modify_flags);
}

/*
  do a sgroup merge
*/
static uint8_t wins_sgroup_merge(struct nbt_name_socket *nbtsock, 
				 struct nbt_name_packet *packet, 
			         struct winsdb_record *rec,
			         const char *address,
			         const struct socket_address *src)
{
	struct nbtd_interface *iface = talloc_get_type(nbtsock->incoming.private_data,
						       struct nbtd_interface);
	struct wins_server *winssrv = iface->nbtsrv->winssrv;
	uint32_t ttl = wins_server_ttl(winssrv, packet->additional[0].ttl);

	rec->expire_time   = time(NULL) + ttl;
	rec->registered_by = src->addr;

	rec->addresses     = winsdb_addr_list_add(winssrv->wins_db,
						  rec, rec->addresses,
						  address,
						  winssrv->wins_db->local_owner,
						  rec->expire_time,
						  true);
	if (rec->addresses == NULL) return NBT_RCODE_SVR;

	DEBUG(5,("WINS: sgroup merge of %s at %s\n",
		 nbt_name_string(packet, rec->name), address));
	
	return winsdb_modify(winssrv->wins_db, rec, WINSDB_FLAG_ALLOC_VERSION | WINSDB_FLAG_TAKE_OWNERSHIP);
}

struct wack_state {
	struct wins_server *winssrv;
	struct nbt_name_socket *nbtsock;
	struct nbt_name_packet *request_packet;
	struct winsdb_record *rec;
	struct socket_address *src;
	const char *reg_address;
	enum wrepl_name_type new_type;
	struct wins_challenge_io io;
	NTSTATUS status;
};

/*
  deny a registration request
*/
static void wins_wack_deny(struct wack_state *s)
{
	nbtd_name_registration_reply(s->nbtsock, s->request_packet, 
				     s->src, NBT_RCODE_ACT);
	DEBUG(4,("WINS: denied name registration request for %s from %s:%d\n",
		 nbt_name_string(s, s->rec->name), s->src->addr, s->src->port));
	talloc_free(s);
}

/*
  allow a registration request
*/
static void wins_wack_allow(struct wack_state *s)
{
	NTSTATUS status;
	uint32_t ttl = wins_server_ttl(s->winssrv, s->request_packet->additional[0].ttl);
	struct winsdb_record *rec = s->rec, *rec2;
	uint32_t i,j;

	status = winsdb_lookup(s->winssrv->wins_db, rec->name, s, &rec2);
	if (!NT_STATUS_IS_OK(status) ||
	    rec2->version != rec->version ||
	    strcmp(rec2->wins_owner, rec->wins_owner) != 0) {
		DEBUG(5,("WINS: record %s changed during WACK - failing registration\n",
			 nbt_name_string(s, rec->name)));
		wins_wack_deny(s);
		return;
	}

	/*
	 * if the old name owner doesn't hold the name anymore
	 * handle the request as new registration for the new name owner
	 */
	if (!NT_STATUS_IS_OK(s->status)) {
		uint8_t rcode;

		winsdb_delete(s->winssrv->wins_db, rec);
		rcode = wins_register_new(s->nbtsock, s->request_packet, s->src, s->new_type);
		if (rcode != NBT_RCODE_OK) {
			DEBUG(1,("WINS: record %s failed to register as new during WACK\n",
				 nbt_name_string(s, rec->name)));
			wins_wack_deny(s);
			return;
		}
		goto done;
	}

	rec->expire_time = time(NULL) + ttl;
	rec->registered_by = s->src->addr;

	/*
	 * now remove all addresses that're the client doesn't hold anymore
	 * and update the time stamp and owner for the ownes that are still there
	 */
	for (i=0; rec->addresses[i]; i++) {
		bool found = false;
		for (j=0; j < s->io.out.num_addresses; j++) {
			if (strcmp(rec->addresses[i]->address, s->io.out.addresses[j]) != 0) continue;

			found = true;
			break;
		}
		if (found) {
			rec->addresses = winsdb_addr_list_add(s->winssrv->wins_db,
							      rec, rec->addresses,
							      s->reg_address,
							      s->winssrv->wins_db->local_owner,
							      rec->expire_time,
							      true);
			if (rec->addresses == NULL) goto failed;
			continue;
		}

		winsdb_addr_list_remove(rec->addresses, rec->addresses[i]->address);
	}

	rec->addresses = winsdb_addr_list_add(s->winssrv->wins_db,
					      rec, rec->addresses,
					      s->reg_address,
					      s->winssrv->wins_db->local_owner,
					      rec->expire_time,
					      true);
	if (rec->addresses == NULL) goto failed;

	/* if we have more than one address, this becomes implicit a MHOMED record */
	if (winsdb_addr_list_length(rec->addresses) > 1) {
		rec->type = WREPL_TYPE_MHOMED;
	}

	winsdb_modify(s->winssrv->wins_db, rec, WINSDB_FLAG_ALLOC_VERSION | WINSDB_FLAG_TAKE_OWNERSHIP);

	DEBUG(4,("WINS: accepted registration of %s with address %s\n",
		 nbt_name_string(s, rec->name), s->reg_address));

done:
	nbtd_name_registration_reply(s->nbtsock, s->request_packet, 
				     s->src, NBT_RCODE_OK);
failed:
	talloc_free(s);
}

/*
  called when a name query to a current owner completes
*/
static void wack_wins_challenge_handler(struct composite_context *c_req)
{
	struct wack_state *s = talloc_get_type(c_req->async.private_data,
					       struct wack_state);
	bool found;
	uint32_t i;

	s->status = wins_challenge_recv(c_req, s, &s->io);

	/*
	 * if the owner denies it holds the name, then allow
	 * the registration
	 */
	if (!NT_STATUS_IS_OK(s->status)) {
		wins_wack_allow(s);
		return;
	}

	if (s->new_type == WREPL_TYPE_GROUP || s->new_type == WREPL_TYPE_SGROUP) {
		DEBUG(1,("WINS: record %s failed to register as group type(%u) during WACK, it's still type(%u)\n",
			 nbt_name_string(s, s->rec->name), s->new_type, s->rec->type));
		wins_wack_deny(s);
		return;
	}

	/*
	 * if the owner still wants the name and doesn't reply
	 * with the address trying to be registered, then deny
	 * the registration
	 */
	found = false;
	for (i=0; i < s->io.out.num_addresses; i++) {
		if (strcmp(s->reg_address, s->io.out.addresses[i]) != 0) continue;

		found = true;
		break;
	}
	if (!found) {
		wins_wack_deny(s);
		return;
	}

	wins_wack_allow(s);
	return;
}


/*
  a client has asked to register a unique name that someone else owns. We
  need to ask each of the current owners if they still want it. If they do
  then reject the registration, otherwise allow it
*/
static void wins_register_wack(struct nbt_name_socket *nbtsock, 
			       struct nbt_name_packet *packet, 
			       struct winsdb_record *rec,
			       struct socket_address *src,
			       enum wrepl_name_type new_type)
{
	struct nbtd_interface *iface = talloc_get_type(nbtsock->incoming.private_data,
						       struct nbtd_interface);
	struct wins_server *winssrv = iface->nbtsrv->winssrv;
	struct wack_state *s;
	struct composite_context *c_req;
	uint32_t ttl;

	s = talloc_zero(nbtsock, struct wack_state);
	if (s == NULL) goto failed;

	/* package up the state variables for this wack request */
	s->winssrv		= winssrv;
	s->nbtsock		= nbtsock;
	s->request_packet	= talloc_steal(s, packet);
	s->rec			= talloc_steal(s, rec);
	s->reg_address		= packet->additional[0].rdata.netbios.addresses[0].ipaddr;
	s->new_type		= new_type;
	s->src		        = src;
	if (talloc_reference(s, src) == NULL) goto failed;

	s->io.in.nbtd_server	= iface->nbtsrv;
	s->io.in.nbt_port       = lp_nbt_port(iface->nbtsrv->task->lp_ctx);
	s->io.in.event_ctx	= iface->nbtsrv->task->event_ctx;
	s->io.in.name		= rec->name;
	s->io.in.num_addresses	= winsdb_addr_list_length(rec->addresses);
	s->io.in.addresses	= winsdb_addr_string_list(s, rec->addresses);
	if (s->io.in.addresses == NULL) goto failed;

	/*
	 * send a WACK to the client, specifying the maximum time it could
         * take to check with the owner, plus some slack
	 */
	ttl = 5 + 4 * winsdb_addr_list_length(rec->addresses);
	nbtd_wack_reply(nbtsock, packet, src, ttl);

	/*
	 * send the challenge to the old addresses
	 */
	c_req = wins_challenge_send(s, &s->io);
	if (c_req == NULL) goto failed;

	c_req->async.fn			= wack_wins_challenge_handler;
	c_req->async.private_data	= s;
	return;

failed:
	talloc_free(s);
	nbtd_name_registration_reply(nbtsock, packet, src, NBT_RCODE_SVR);
}

/*
  register a name
*/
static void nbtd_winsserver_register(struct nbt_name_socket *nbtsock, 
				     struct nbt_name_packet *packet, 
				     struct socket_address *src)
{
	NTSTATUS status;
	struct nbtd_interface *iface = talloc_get_type(nbtsock->incoming.private_data,
						       struct nbtd_interface);
	struct wins_server *winssrv = iface->nbtsrv->winssrv;
	struct nbt_name *name = &packet->questions[0].name;
	struct winsdb_record *rec;
	uint8_t rcode = NBT_RCODE_OK;
	uint16_t nb_flags = packet->additional[0].rdata.netbios.addresses[0].nb_flags;
	const char *address = packet->additional[0].rdata.netbios.addresses[0].ipaddr;
	bool mhomed = ((packet->operation & NBT_OPCODE) == NBT_OPCODE_MULTI_HOME_REG);
	enum wrepl_name_type new_type = wrepl_type(nb_flags, name, mhomed);
	struct winsdb_addr *winsdb_addr = NULL;

	/*
	 * as a special case, the local master browser name is always accepted
	 * for registration, but never stored, but w2k3 stores it if it's registered
	 * as a group name, (but a query for the 0x1D name still returns not found!)
	 */
	if (name->type == NBT_NAME_MASTER && !(nb_flags & NBT_NM_GROUP)) {
		rcode = NBT_RCODE_OK;
		goto done;
	}

	/* w2k3 refuses 0x1B names with marked as group */
	if (name->type == NBT_NAME_PDC && (nb_flags & NBT_NM_GROUP)) {
		rcode = NBT_RCODE_RFS;
		goto done;
	}

	/* w2k3 refuses 0x1C names with out marked as group */
	if (name->type == NBT_NAME_LOGON && !(nb_flags & NBT_NM_GROUP)) {
		rcode = NBT_RCODE_RFS;
		goto done;
	}

	/* w2k3 refuses 0x1E names with out marked as group */
	if (name->type == NBT_NAME_BROWSER && !(nb_flags & NBT_NM_GROUP)) {
		rcode = NBT_RCODE_RFS;
		goto done;
	}

	status = winsdb_lookup(winssrv->wins_db, name, packet, &rec);
	if (NT_STATUS_EQUAL(NT_STATUS_OBJECT_NAME_NOT_FOUND, status)) {
		rcode = wins_register_new(nbtsock, packet, src, new_type);
		goto done;
	} else if (!NT_STATUS_IS_OK(status)) {
		rcode = NBT_RCODE_SVR;
		goto done;
	} else if (rec->is_static) {
		if (rec->type == WREPL_TYPE_GROUP || rec->type == WREPL_TYPE_SGROUP) {
			rcode = NBT_RCODE_OK;
			goto done;
		}
		rcode = NBT_RCODE_ACT;
		goto done;
	}

	if (rec->type == WREPL_TYPE_GROUP) {
		if (new_type != WREPL_TYPE_GROUP) {
			DEBUG(2,("WINS: Attempt to register name %s as non normal group(%u)"
				 " while a normal group is already there\n",
				 nbt_name_string(packet, name), new_type));
			rcode = NBT_RCODE_ACT;
			goto done;
		}

		if (rec->state == WREPL_STATE_ACTIVE) {
			/* TODO: is this correct? */
			rcode = wins_update_ttl(nbtsock, packet, rec, NULL, src);
			goto done;
		}

		/* TODO: is this correct? */
		winsdb_delete(winssrv->wins_db, rec);
		rcode = wins_register_new(nbtsock, packet, src, new_type);
		goto done;
	}

	if (rec->state != WREPL_STATE_ACTIVE) {
		winsdb_delete(winssrv->wins_db, rec);
		rcode = wins_register_new(nbtsock, packet, src, new_type);
		goto done;
	}

	switch (rec->type) {
	case WREPL_TYPE_UNIQUE:
	case WREPL_TYPE_MHOMED:
		/* 
		 * if its an active unique name, and the registration is for a group, then
		 * see if the unique name owner still wants the name
		 * TODO: is this correct?
		 */
		if (new_type == WREPL_TYPE_GROUP || new_type == WREPL_TYPE_GROUP) {
			wins_register_wack(nbtsock, packet, rec, src, new_type);
			return;
		}

		/* 
		 * if the registration is for an address that is currently active, then 
		 * just update the expiry time of the record and the address
		 */
		winsdb_addr = winsdb_addr_list_check(rec->addresses, address);
		if (winsdb_addr) {
			rcode = wins_update_ttl(nbtsock, packet, rec, winsdb_addr, src);
			goto done;
		}

		/*
		 * we have to do a WACK to see if the current owner is willing
		 * to give up its claim
		 */
		wins_register_wack(nbtsock, packet, rec, src, new_type);
		return;

	case WREPL_TYPE_GROUP:
		/* this should not be reached as normal groups are handled above */
		DEBUG(0,("BUG at %s\n",__location__));
		rcode = NBT_RCODE_ACT;
		goto done;

	case WREPL_TYPE_SGROUP:
		/* if the new record isn't also a special group, refuse the registration */ 
		if (new_type != WREPL_TYPE_SGROUP) {
			DEBUG(2,("WINS: Attempt to register name %s as non special group(%u)"
				 " while a special group is already there\n",
				 nbt_name_string(packet, name), new_type));
			rcode = NBT_RCODE_ACT;
			goto done;
		}

		/* 
		 * if the registration is for an address that is currently active, then 
		 * just update the expiry time of the record and the address
		 */
		winsdb_addr = winsdb_addr_list_check(rec->addresses, address);
		if (winsdb_addr) {
			rcode = wins_update_ttl(nbtsock, packet, rec, winsdb_addr, src);
			goto done;
		}

		rcode = wins_sgroup_merge(nbtsock, packet, rec, address, src);
		goto done;
	}

done:
	nbtd_name_registration_reply(nbtsock, packet, src, rcode);
}

static uint32_t ipv4_match_bits(struct in_addr ip1, struct in_addr ip2)
{
	uint32_t i, j, match=0;
	uint8_t *p1, *p2;

	p1 = (uint8_t *)&ip1.s_addr;
	p2 = (uint8_t *)&ip2.s_addr;

	for (i=0; i<4; i++) {
		if (p1[i] != p2[i]) break;
		match += 8;
	}

	if (i==4) return match;

	for (j=0; j<8; j++) {
		if ((p1[i] & (1<<(7-j))) != (p2[i] & (1<<(7-j))))
			break;
		match++;
	}

	return match;
}

static int nbtd_wins_randomize1Clist_sort(void *p1,/* (const char **) */
					  void *p2,/* (const char **) */
					  struct socket_address *src)
{
	const char *a1 = (const char *)*(const char **)p1;
	const char *a2 = (const char *)*(const char **)p2;
	uint32_t match_bits1;
	uint32_t match_bits2;

	match_bits1 = ipv4_match_bits(interpret_addr2(a1), interpret_addr2(src->addr));
	match_bits2 = ipv4_match_bits(interpret_addr2(a2), interpret_addr2(src->addr));

	return match_bits2 - match_bits1;
}

static void nbtd_wins_randomize1Clist(struct loadparm_context *lp_ctx,
				      const char **addresses, struct socket_address *src)
{
	const char *mask;
	const char *tmp;
	uint32_t num_addrs;
	uint32_t idx, sidx;
	int r;

	for (num_addrs=0; addresses[num_addrs]; num_addrs++) { /* noop */ }

	if (num_addrs <= 1) return; /* nothing to do */

	/* first sort the addresses depending on the matching to the client */
	ldb_qsort(addresses, num_addrs , sizeof(addresses[0]),
		  src, (ldb_qsort_cmp_fn_t)nbtd_wins_randomize1Clist_sort);

	mask = lp_parm_string(lp_ctx, NULL, "nbtd", "wins_randomize1Clist_mask");
	if (!mask) {
		mask = "255.255.255.0";
	}

	/* 
	 * choose a random address to be the first in the response to the client,
	 * preferr the addresses inside the nbtd:wins_randomize1Clist_mask netmask
	 */
	r = random();
	idx = sidx = r % num_addrs;

	while (1) {
		bool same;

		/* if the current one is in the same subnet, use it */
		same = iface_same_net(addresses[idx], src->addr, mask);
		if (same) {
			sidx = idx;
			break;
		}

		/* we need to check for idx == 0, after checking for the same net */
		if (idx == 0) break;
		/* 
		 * if we haven't found an address in the same subnet, search in ones
		 * which match the client more
		 *
		 * some notes:
		 *
		 * it's not "idx = idx % r" but "idx = r % idx"
		 * because in "a % b" b is the allowed range
		 * and b-1 is the maximum possible result, so it must be decreasing
		 * and the above idx == 0 check breaks the while(1) loop.
		 */
		idx = r % idx;
	}

	/* note sidx == 0 is also valid here ... */
	tmp		= addresses[0];
	addresses[0]	= addresses[sidx];
	addresses[sidx]	= tmp;
}

/*
  query a name
*/
static void nbtd_winsserver_query(struct loadparm_context *lp_ctx,
				  struct nbt_name_socket *nbtsock, 
				  struct nbt_name_packet *packet, 
				  struct socket_address *src)
{
	NTSTATUS status;
	struct nbtd_interface *iface = talloc_get_type(nbtsock->incoming.private_data,
						       struct nbtd_interface);
	struct wins_server *winssrv = iface->nbtsrv->winssrv;
	struct nbt_name *name = &packet->questions[0].name;
	struct winsdb_record *rec;
	struct winsdb_record *rec_1b = NULL;
	const char **addresses;
	const char **addresses_1b = NULL;
	uint16_t nb_flags = 0;

	if (name->type == NBT_NAME_MASTER) {
		goto notfound;
	}

	/*
	 * w2k3 returns the first address of the 0x1B record as first address
	 * to a 0x1C query
	 *
	 * since Windows 2000 Service Pack 2 there's on option to trigger this behavior:
	 *
	 * HKEY_LOCAL_MACHINE\System\CurrentControlset\Services\WINS\Parameters\Prepend1BTo1CQueries
	 * Typ: Daten REG_DWORD
	 * Value: 0 = deactivated, 1 = activated
	 */
	if (name->type == NBT_NAME_LOGON && 
	    lp_parm_bool(lp_ctx, NULL, "nbtd", "wins_prepend1Bto1Cqueries", true)) {
		struct nbt_name name_1b;

		name_1b = *name;
		name_1b.type = NBT_NAME_PDC;

		status = winsdb_lookup(winssrv->wins_db, &name_1b, packet, &rec_1b);
		if (NT_STATUS_IS_OK(status)) {
			addresses_1b = winsdb_addr_string_list(packet, rec_1b->addresses);
		}
	}

	status = winsdb_lookup(winssrv->wins_db, name, packet, &rec);
	if (!NT_STATUS_IS_OK(status)) {
		if (!lp_wins_dns_proxy(lp_ctx)) {
			goto notfound;
		}

		if (name->type != NBT_NAME_CLIENT && name->type != NBT_NAME_SERVER) {
			goto notfound;
		}

		nbtd_wins_dns_proxy_query(nbtsock, packet, src);
		return;
	}

	/*
	 * for group's we always reply with
	 * 255.255.255.255 as address, even if
	 * the record is released or tombstoned
	 */
	if (rec->type == WREPL_TYPE_GROUP) {
		addresses = str_list_add(NULL, "255.255.255.255");
		talloc_steal(packet, addresses);
		if (!addresses) {
			goto notfound;
		}
		nb_flags |= NBT_NM_GROUP;
		goto found;
	}

	if (rec->state != WREPL_STATE_ACTIVE) {
		goto notfound;
	}

	addresses = winsdb_addr_string_list(packet, rec->addresses);
	if (!addresses) {
		goto notfound;
	}

	/* 
	 * if addresses_1b isn't NULL, we have a 0x1C query and need to return the
	 * first 0x1B address as first address
	 */
	if (addresses_1b && addresses_1b[0]) {
		const char **addresses_1c = addresses;
		uint32_t i;
		uint32_t num_addrs;

		addresses = str_list_add(NULL, addresses_1b[0]);
		if (!addresses) {
			goto notfound;
		}
		talloc_steal(packet, addresses);
		num_addrs = 1;

		for (i=0; addresses_1c[i]; i++) {
			if (strcmp(addresses_1b[0], addresses_1c[i]) == 0) continue;

			/*
			 * stop when we already have 25 addresses
			 */
			if (num_addrs >= 25) break;

			num_addrs++;			
			addresses = str_list_add(addresses, addresses_1c[i]);
			if (!addresses) {
				goto notfound;
			}
		}
	}

	if (rec->type == WREPL_TYPE_SGROUP) {
		nb_flags |= NBT_NM_GROUP;
	} else {
		nb_flags |= (rec->node <<13);
	}

	/*
	 * since Windows 2000 Service Pack 2 there's on option to trigger this behavior:
	 *
	 * HKEY_LOCAL_MACHINE\System\CurrentControlset\Services\WINS\Parameters\Randomize1CList
	 * Typ: Daten REG_DWORD
	 * Value: 0 = deactivated, 1 = activated
	 */
	if (name->type == NBT_NAME_LOGON && 
	    lp_parm_bool(lp_ctx, NULL, "nbtd", "wins_randomize1Clist", false)) {
		nbtd_wins_randomize1Clist(lp_ctx, addresses, src);
	}

found:
	nbtd_name_query_reply(nbtsock, packet, src, name, 
			      0, nb_flags, addresses);
	return;

notfound:
	nbtd_negative_name_query_reply(nbtsock, packet, src);
}

/*
  release a name
*/
static void nbtd_winsserver_release(struct nbt_name_socket *nbtsock, 
				    struct nbt_name_packet *packet, 
				    struct socket_address *src)
{
	NTSTATUS status;
	struct nbtd_interface *iface = talloc_get_type(nbtsock->incoming.private_data,
						       struct nbtd_interface);
	struct wins_server *winssrv = iface->nbtsrv->winssrv;
	struct nbt_name *name = &packet->questions[0].name;
	struct winsdb_record *rec;
	uint32_t modify_flags = 0;
	uint8_t ret;

	if (name->type == NBT_NAME_MASTER) {
		goto done;
	}

	status = winsdb_lookup(winssrv->wins_db, name, packet, &rec);
	if (!NT_STATUS_IS_OK(status)) {
		goto done;
	}

	if (rec->is_static) {
		if (rec->type == WREPL_TYPE_UNIQUE || rec->type == WREPL_TYPE_MHOMED) {
			goto done;
		}
		nbtd_name_release_reply(nbtsock, packet, src, NBT_RCODE_ACT);
		return;
	}

	if (rec->state != WREPL_STATE_ACTIVE) {
		goto done;
	}

	/* 
	 * TODO: do we need to check if
	 *       src->addr matches packet->additional[0].rdata.netbios.addresses[0].ipaddr
	 *       here?
	 */

	/* 
	 * we only allow releases from an owner - other releases are
	 * silently ignored
	 */
	if (!winsdb_addr_list_check(rec->addresses, src->addr)) {
		int i;
		DEBUG(4,("WINS: silently ignoring attempted name release on %s from %s\n", nbt_name_string(rec, rec->name), src->addr));
		DEBUGADD(4, ("Registered Addresses: \n"));
		for (i=0; rec->addresses && rec->addresses[i]; i++) {
			DEBUGADD(4, ("%s\n", rec->addresses[i]->address));
		}
		goto done;
	}

	DEBUG(4,("WINS: released name %s from %s\n", nbt_name_string(rec, rec->name), src->addr));

	switch (rec->type) {
	case WREPL_TYPE_UNIQUE:
		rec->state = WREPL_STATE_RELEASED;
		break;

	case WREPL_TYPE_GROUP:
		rec->state = WREPL_STATE_RELEASED;
		break;

	case WREPL_TYPE_SGROUP:
		winsdb_addr_list_remove(rec->addresses, src->addr);
		/* TODO: do we need to take the ownership here? */
		if (winsdb_addr_list_length(rec->addresses) == 0) {
			rec->state = WREPL_STATE_RELEASED;
		}
		break;

	case WREPL_TYPE_MHOMED:
		winsdb_addr_list_remove(rec->addresses, src->addr);
		/* TODO: do we need to take the ownership here? */
		if (winsdb_addr_list_length(rec->addresses) == 0) {
			rec->state = WREPL_STATE_RELEASED;
		}
		break;
	}

	if (rec->state == WREPL_STATE_RELEASED) {
		/*
		 * if we're not the owner, we need to take the owner ship
		 * and make the record tombstone, but expire after
		 * tombstone_interval + tombstone_timeout and not only after tombstone_timeout
		 * like for normal tombstone records.
		 * This is to replicate the record directly to the original owner,
		 * where the record is still active
		 */ 
		if (strcmp(rec->wins_owner, winssrv->wins_db->local_owner) == 0) {
			rec->expire_time= time(NULL) + winssrv->config.tombstone_interval;
		} else {
			rec->state	= WREPL_STATE_TOMBSTONE;
			rec->expire_time= time(NULL) + 
					  winssrv->config.tombstone_interval +
					  winssrv->config.tombstone_timeout;
			modify_flags	= WINSDB_FLAG_ALLOC_VERSION | WINSDB_FLAG_TAKE_OWNERSHIP;
		}
	}

	ret = winsdb_modify(winssrv->wins_db, rec, modify_flags);
	if (ret != NBT_RCODE_OK) {
		DEBUG(1,("WINS: FAILED: released name %s at %s: error:%u\n",
			nbt_name_string(rec, rec->name), src->addr, ret));
	}
done:
	/* we match w2k3 by always giving a positive reply to name releases. */
	nbtd_name_release_reply(nbtsock, packet, src, NBT_RCODE_OK);
}


/*
  answer a name query
*/
void nbtd_winsserver_request(struct nbt_name_socket *nbtsock, 
			     struct nbt_name_packet *packet, 
			     struct socket_address *src)
{
	struct nbtd_interface *iface = talloc_get_type(nbtsock->incoming.private_data,
						       struct nbtd_interface);
	struct wins_server *winssrv = iface->nbtsrv->winssrv;
	if ((packet->operation & NBT_FLAG_BROADCAST) || winssrv == NULL) {
		return;
	}

	switch (packet->operation & NBT_OPCODE) {
	case NBT_OPCODE_QUERY:
		nbtd_winsserver_query(iface->nbtsrv->task->lp_ctx, nbtsock, packet, src);
		break;

	case NBT_OPCODE_REGISTER:
	case NBT_OPCODE_REFRESH:
	case NBT_OPCODE_REFRESH2:
	case NBT_OPCODE_MULTI_HOME_REG:
		nbtd_winsserver_register(nbtsock, packet, src);
		break;

	case NBT_OPCODE_RELEASE:
		nbtd_winsserver_release(nbtsock, packet, src);
		break;
	}

}

/*
  startup the WINS server, if configured
*/
NTSTATUS nbtd_winsserver_init(struct nbtd_server *nbtsrv)
{
	uint32_t tmp;
	const char *owner;

	if (!lp_wins_support(nbtsrv->task->lp_ctx)) {
		nbtsrv->winssrv = NULL;
		return NT_STATUS_OK;
	}

	nbtsrv->winssrv = talloc_zero(nbtsrv, struct wins_server);
	NT_STATUS_HAVE_NO_MEMORY(nbtsrv->winssrv);

	nbtsrv->winssrv->config.max_renew_interval = lp_max_wins_ttl(nbtsrv->task->lp_ctx);
	nbtsrv->winssrv->config.min_renew_interval = lp_min_wins_ttl(nbtsrv->task->lp_ctx);
	tmp = lp_parm_int(nbtsrv->task->lp_ctx, NULL, "wreplsrv", "tombstone_interval", 6*24*60*60);
	nbtsrv->winssrv->config.tombstone_interval = tmp;
	tmp = lp_parm_int(nbtsrv->task->lp_ctx, NULL, "wreplsrv"," tombstone_timeout", 1*24*60*60);
	nbtsrv->winssrv->config.tombstone_timeout = tmp;

	owner = lp_parm_string(nbtsrv->task->lp_ctx, NULL, "winsdb", "local_owner");

	if (owner == NULL) {
		struct interface *ifaces;
		load_interfaces(nbtsrv->task, lp_interfaces(nbtsrv->task->lp_ctx), &ifaces);
		owner = iface_n_ip(ifaces, 0);
	}

	nbtsrv->winssrv->wins_db     = winsdb_connect(nbtsrv->winssrv, nbtsrv->task->event_ctx, 
						      nbtsrv->task->lp_ctx,
						      owner, WINSDB_HANDLE_CALLER_NBTD);
	if (!nbtsrv->winssrv->wins_db) {
		return NT_STATUS_INTERNAL_DB_ERROR;
	}

	irpc_add_name(nbtsrv->task->msg_ctx, "wins_server");

	return NT_STATUS_OK;
}