summaryrefslogtreecommitdiffstats
path: root/net/tipc/name_table.c
blob: 5d700426264774adc6a963f6437f404a2a022d36 (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
/*
 * net/tipc/name_table.c: TIPC name table code
 *
 * Copyright (c) 2000-2006, Ericsson AB
 * Copyright (c) 2004-2008, 2010-2011, Wind River Systems
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the names of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "core.h"
#include "config.h"
#include "name_table.h"
#include "name_distr.h"
#include "subscr.h"
#include "port.h"

static int tipc_nametbl_size = 1024;		/* must be a power of 2 */

/**
 * struct name_info - name sequence publication info
 * @node_list: circular list of publications made by own node
 * @cluster_list: circular list of publications made by own cluster
 * @zone_list: circular list of publications made by own zone
 * @node_list_size: number of entries in "node_list"
 * @cluster_list_size: number of entries in "cluster_list"
 * @zone_list_size: number of entries in "zone_list"
 *
 * Note: The zone list always contains at least one entry, since all
 *       publications of the associated name sequence belong to it.
 *       (The cluster and node lists may be empty.)
 */

struct name_info {
	struct list_head node_list;
	struct list_head cluster_list;
	struct list_head zone_list;
	u32 node_list_size;
	u32 cluster_list_size;
	u32 zone_list_size;
};

/**
 * struct sub_seq - container for all published instances of a name sequence
 * @lower: name sequence lower bound
 * @upper: name sequence upper bound
 * @info: pointer to name sequence publication info
 */

struct sub_seq {
	u32 lower;
	u32 upper;
	struct name_info *info;
};

/**
 * struct name_seq - container for all published instances of a name type
 * @type: 32 bit 'type' value for name sequence
 * @sseq: pointer to dynamically-sized array of sub-sequences of this 'type';
 *        sub-sequences are sorted in ascending order
 * @alloc: number of sub-sequences currently in array
 * @first_free: array index of first unused sub-sequence entry
 * @ns_list: links to adjacent name sequences in hash chain
 * @subscriptions: list of subscriptions for this 'type'
 * @lock: spinlock controlling access to publication lists of all sub-sequences
 */

struct name_seq {
	u32 type;
	struct sub_seq *sseqs;
	u32 alloc;
	u32 first_free;
	struct hlist_node ns_list;
	struct list_head subscriptions;
	spinlock_t lock;
};

/**
 * struct name_table - table containing all existing port name publications
 * @types: pointer to fixed-sized array of name sequence lists,
 *         accessed via hashing on 'type'; name sequence lists are *not* sorted
 * @local_publ_count: number of publications issued by this node
 */

struct name_table {
	struct hlist_head *types;
	u32 local_publ_count;
};

static struct name_table table;
DEFINE_RWLOCK(tipc_nametbl_lock);

static int hash(int x)
{
	return x & (tipc_nametbl_size - 1);
}

/**
 * publ_create - create a publication structure
 */

static struct publication *publ_create(u32 type, u32 lower, u32 upper,
				       u32 scope, u32 node, u32 port_ref,
				       u32 key)
{
	struct publication *publ = kzalloc(sizeof(*publ), GFP_ATOMIC);
	if (publ == NULL) {
		warn("Publication creation failure, no memory\n");
		return NULL;
	}

	publ->type = type;
	publ->lower = lower;
	publ->upper = upper;
	publ->scope = scope;
	publ->node = node;
	publ->ref = port_ref;
	publ->key = key;
	INIT_LIST_HEAD(&publ->local_list);
	INIT_LIST_HEAD(&publ->pport_list);
	INIT_LIST_HEAD(&publ->subscr.nodesub_list);
	return publ;
}

/**
 * tipc_subseq_alloc - allocate a specified number of sub-sequence structures
 */

static struct sub_seq *tipc_subseq_alloc(u32 cnt)
{
	struct sub_seq *sseq = kcalloc(cnt, sizeof(struct sub_seq), GFP_ATOMIC);
	return sseq;
}

/**
 * tipc_nameseq_create - create a name sequence structure for the specified 'type'
 *
 * Allocates a single sub-sequence structure and sets it to all 0's.
 */

static struct name_seq *tipc_nameseq_create(u32 type, struct hlist_head *seq_head)
{
	struct name_seq *nseq = kzalloc(sizeof(*nseq), GFP_ATOMIC);
	struct sub_seq *sseq = tipc_subseq_alloc(1);

	if (!nseq || !sseq) {
		warn("Name sequence creation failed, no memory\n");
		kfree(nseq);
		kfree(sseq);
		return NULL;
	}

	spin_lock_init(&nseq->lock);
	nseq->type = type;
	nseq->sseqs = sseq;
	nseq->alloc = 1;
	INIT_HLIST_NODE(&nseq->ns_list);
	INIT_LIST_HEAD(&nseq->subscriptions);
	hlist_add_head(&nseq->ns_list, seq_head);
	return nseq;
}

/**
 * nameseq_find_subseq - find sub-sequence (if any) matching a name instance
 *
 * Very time-critical, so binary searches through sub-sequence array.
 */

static struct sub_seq *nameseq_find_subseq(struct name_seq *nseq,
					   u32 instance)
{
	struct sub_seq *sseqs = nseq->sseqs;
	int low = 0;
	int high = nseq->first_free - 1;
	int mid;

	while (low <= high) {
		mid = (low + high) / 2;
		if (instance < sseqs[mid].lower)
			high = mid - 1;
		else if (instance > sseqs[mid].upper)
			low = mid + 1;
		else
			return &sseqs[mid];
	}
	return NULL;
}

/**
 * nameseq_locate_subseq - determine position of name instance in sub-sequence
 *
 * Returns index in sub-sequence array of the entry that contains the specified
 * instance value; if no entry contains that value, returns the position
 * where a new entry for it would be inserted in the array.
 *
 * Note: Similar to binary search code for locating a sub-sequence.
 */

static u32 nameseq_locate_subseq(struct name_seq *nseq, u32 instance)
{
	struct sub_seq *sseqs = nseq->sseqs;
	int low = 0;
	int high = nseq->first_free - 1;
	int mid;

	while (low <= high) {
		mid = (low + high) / 2;
		if (instance < sseqs[mid].lower)
			high = mid - 1;
		else if (instance > sseqs[mid].upper)
			low = mid + 1;
		else
			return mid;
	}
	return low;
}

/**
 * tipc_nameseq_insert_publ -
 */

static struct publication *tipc_nameseq_insert_publ(struct name_seq *nseq,
						    u32 type, u32 lower, u32 upper,
						    u32 scope, u32 node, u32 port, u32 key)
{
	struct tipc_subscription *s;
	struct tipc_subscription *st;
	struct publication *publ;
	struct sub_seq *sseq;
	struct name_info *info;
	int created_subseq = 0;

	sseq = nameseq_find_subseq(nseq, lower);
	if (sseq) {

		/* Lower end overlaps existing entry => need an exact match */

		if ((sseq->lower != lower) || (sseq->upper != upper)) {
			warn("Cannot publish {%u,%u,%u}, overlap error\n",
			     type, lower, upper);
			return NULL;
		}

		info = sseq->info;

		/* Check if an identical publication already exists */
		list_for_each_entry(publ, &info->zone_list, zone_list) {
			if ((publ->ref == port) && (publ->key == key) &&
			    (!publ->node || (publ->node == node)))
				return NULL;
		}
	} else {
		u32 inspos;
		struct sub_seq *freesseq;

		/* Find where lower end should be inserted */

		inspos = nameseq_locate_subseq(nseq, lower);

		/* Fail if upper end overlaps into an existing entry */

		if ((inspos < nseq->first_free) &&
		    (upper >= nseq->sseqs[inspos].lower)) {
			warn("Cannot publish {%u,%u,%u}, overlap error\n",
			     type, lower, upper);
			return NULL;
		}

		/* Ensure there is space for new sub-sequence */

		if (nseq->first_free == nseq->alloc) {
			struct sub_seq *sseqs = tipc_subseq_alloc(nseq->alloc * 2);

			if (!sseqs) {
				warn("Cannot publish {%u,%u,%u}, no memory\n",
				     type, lower, upper);
				return NULL;
			}
			memcpy(sseqs, nseq->sseqs,
			       nseq->alloc * sizeof(struct sub_seq));
			kfree(nseq->sseqs);
			nseq->sseqs = sseqs;
			nseq->alloc *= 2;
		}

		info = kzalloc(sizeof(*info), GFP_ATOMIC);
		if (!info) {
			warn("Cannot publish {%u,%u,%u}, no memory\n",
			     type, lower, upper);
			return NULL;
		}

		INIT_LIST_HEAD(&info->node_list);
		INIT_LIST_HEAD(&info->cluster_list);
		INIT_LIST_HEAD(&info->zone_list);

		/* Insert new sub-sequence */

		sseq = &nseq->sseqs[inspos];
		freesseq = &nseq->sseqs[nseq->first_free];
		memmove(sseq + 1, sseq, (freesseq - sseq) * sizeof(*sseq));
		memset(sseq, 0, sizeof(*sseq));
		nseq->first_free++;
		sseq->lower = lower;
		sseq->upper = upper;
		sseq->info = info;
		created_subseq = 1;
	}

	/* Insert a publication: */

	publ = publ_create(type, lower, upper, scope, node, port, key);
	if (!publ)
		return NULL;

	list_add(&publ->zone_list, &info->zone_list);
	info->zone_list_size++;

	if (in_own_cluster(node)) {
		list_add(&publ->cluster_list, &info->cluster_list);
		info->cluster_list_size++;
	}

	if (node == tipc_own_addr) {
		list_add(&publ->node_list, &info->node_list);
		info->node_list_size++;
	}

	/*
	 * Any subscriptions waiting for notification?
	 */
	list_for_each_entry_safe(s, st, &nseq->subscriptions, nameseq_list) {
		tipc_subscr_report_overlap(s,
					   publ->lower,
					   publ->upper,
					   TIPC_PUBLISHED,
					   publ->ref,
					   publ->node,
					   created_subseq);
	}
	return publ;
}

/**
 * tipc_nameseq_remove_publ -
 *
 * NOTE: There may be cases where TIPC is asked to remove a publication
 * that is not in the name table.  For example, if another node issues a
 * publication for a name sequence that overlaps an existing name sequence
 * the publication will not be recorded, which means the publication won't
 * be found when the name sequence is later withdrawn by that node.
 * A failed withdraw request simply returns a failure indication and lets the
 * caller issue any error or warning messages associated with such a problem.
 */

static struct publication *tipc_nameseq_remove_publ(struct name_seq *nseq, u32 inst,
						    u32 node, u32 ref, u32 key)
{
	struct publication *publ;
	struct sub_seq *sseq = nameseq_find_subseq(nseq, inst);
	struct name_info *info;
	struct sub_seq *free;
	struct tipc_subscription *s, *st;
	int removed_subseq = 0;

	if (!sseq)
		return NULL;

	info = sseq->info;

	/* Locate publication, if it exists */

	list_for_each_entry(publ, &info->zone_list, zone_list) {
		if ((publ->key == key) && (publ->ref == ref) &&
		    (!publ->node || (publ->node == node)))
			goto found;
	}
	return NULL;

found:
	/* Remove publication from zone scope list */

	list_del(&publ->zone_list);
	info->zone_list_size--;

	/* Remove publication from cluster scope list, if present */

	if (in_own_cluster(node)) {
		list_del(&publ->cluster_list);
		info->cluster_list_size--;
	}

	/* Remove publication from node scope list, if present */

	if (node == tipc_own_addr) {
		list_del(&publ->node_list);
		info->node_list_size--;
	}

	/* Contract subseq list if no more publications for that subseq */

	if (list_empty(&info->zone_list)) {
		kfree(info);
		free = &nseq->sseqs[nseq->first_free--];
		memmove(sseq, sseq + 1, (free - (sseq + 1)) * sizeof(*sseq));
		removed_subseq = 1;
	}

	/* Notify any waiting subscriptions */

	list_for_each_entry_safe(s, st, &nseq->subscriptions, nameseq_list) {
		tipc_subscr_report_overlap(s,
					   publ->lower,
					   publ->upper,
					   TIPC_WITHDRAWN,
					   publ->ref,
					   publ->node,
					   removed_subseq);
	}

	return publ;
}

/**
 * tipc_nameseq_subscribe: attach a subscription, and issue
 * the prescribed number of events if there is any sub-
 * sequence overlapping with the requested sequence
 */

static void tipc_nameseq_subscribe(struct name_seq *nseq,
					struct tipc_subscription *s)
{
	struct sub_seq *sseq = nseq->sseqs;

	list_add(&s->nameseq_list, &nseq->subscriptions);

	if (!sseq)
		return;

	while (sseq != &nseq->sseqs[nseq->first_free]) {
		if (tipc_subscr_overlap(s, sseq->lower, sseq->upper)) {
			struct publication *crs;
			struct name_info *info = sseq->info;
			int must_report = 1;

			list_for_each_entry(crs, &info->zone_list, zone_list) {
				tipc_subscr_report_overlap(s,
							   sseq->lower,
							   sseq->upper,
							   TIPC_PUBLISHED,
							   crs->ref,
							   crs->node,
							   must_report);
				must_report = 0;
			}
		}
		sseq++;
	}
}

static struct name_seq *nametbl_find_seq(u32 type)
{
	struct hlist_head *seq_head;
	struct hlist_node *seq_node;
	struct name_seq *ns;

	seq_head = &table.types[hash(type)];
	hlist_for_each_entry(ns, seq_node, seq_head, ns_list) {
		if (ns->type == type)
			return ns;
	}

	return NULL;
};

struct publication *tipc_nametbl_insert_publ(u32 type, u32 lower, u32 upper,
					     u32 scope, u32 node, u32 port, u32 key)
{
	struct name_seq *seq = nametbl_find_seq(type);

	if (lower > upper) {
		warn("Failed to publish illegal {%u,%u,%u}\n",
		     type, lower, upper);
		return NULL;
	}

	if (!seq)
		seq = tipc_nameseq_create(type, &table.types[hash(type)]);
	if (!seq)
		return NULL;

	return tipc_nameseq_insert_publ(seq, type, lower, upper,
					scope, node, port, key);
}

struct publication *tipc_nametbl_remove_publ(u32 type, u32 lower,
					     u32 node, u32 ref, u32 key)
{
	struct publication *publ;
	struct name_seq *seq = nametbl_find_seq(type);

	if (!seq)
		return NULL;

	publ = tipc_nameseq_remove_publ(seq, lower, node, ref, key);

	if (!seq->first_free && list_empty(&seq->subscriptions)) {
		hlist_del_init(&seq->ns_list);
		kfree(seq->sseqs);
		kfree(seq);
	}
	return publ;
}

/*
 * tipc_nametbl_translate - perform name translation
 *
 * On entry, 'destnode' is the search domain used during translation.
 *
 * On exit:
 * - if name translation is deferred to another node/cluster/zone,
 *   leaves 'destnode' unchanged (will be non-zero) and returns 0
 * - if name translation is attempted and succeeds, sets 'destnode'
 *   to publishing node and returns port reference (will be non-zero)
 * - if name translation is attempted and fails, sets 'destnode' to 0
 *   and returns 0
 */

u32 tipc_nametbl_translate(u32 type, u32 instance, u32 *destnode)
{
	struct sub_seq *sseq;
	struct name_info *info;
	struct publication *publ;
	struct name_seq *seq;
	u32 ref = 0;
	u32 node = 0;

	if (!tipc_in_scope(*destnode, tipc_own_addr))
		return 0;

	read_lock_bh(&tipc_nametbl_lock);
	seq = nametbl_find_seq(type);
	if (unlikely(!seq))
		goto not_found;
	sseq = nameseq_find_subseq(seq, instance);
	if (unlikely(!sseq))
		goto not_found;
	spin_lock_bh(&seq->lock);
	info = sseq->info;

	/* Closest-First Algorithm: */
	if (likely(!*destnode)) {
		if (!list_empty(&info->node_list)) {
			publ = list_first_entry(&info->node_list,
						struct publication,
						node_list);
			list_move_tail(&publ->node_list,
				       &info->node_list);
		} else if (!list_empty(&info->cluster_list)) {
			publ = list_first_entry(&info->cluster_list,
						struct publication,
						cluster_list);
			list_move_tail(&publ->cluster_list,
				       &info->cluster_list);
		} else {
			publ = list_first_entry(&info->zone_list,
						struct publication,
						zone_list);
			list_move_tail(&publ->zone_list,
				       &info->zone_list);
		}
	}

	/* Round-Robin Algorithm: */
	else if (*destnode == tipc_own_addr) {
		if (list_empty(&info->node_list))
			goto no_match;
		publ = list_first_entry(&info->node_list, struct publication,
					node_list);
		list_move_tail(&publ->node_list, &info->node_list);
	} else if (in_own_cluster(*destnode)) {
		if (list_empty(&info->cluster_list))
			goto no_match;
		publ = list_first_entry(&info->cluster_list, struct publication,
					cluster_list);
		list_move_tail(&publ->cluster_list, &info->cluster_list);
	} else {
		publ = list_first_entry(&info->zone_list, struct publication,
					zone_list);
		list_move_tail(&publ->zone_list, &info->zone_list);
	}

	ref = publ->ref;
	node = publ->node;
no_match:
	spin_unlock_bh(&seq->lock);
not_found:
	read_unlock_bh(&tipc_nametbl_lock);
	*destnode = node;
	return ref;
}

/**
 * tipc_nametbl_mc_translate - find multicast destinations
 *
 * Creates list of all local ports that overlap the given multicast address;
 * also determines if any off-node ports overlap.
 *
 * Note: Publications with a scope narrower than 'limit' are ignored.
 * (i.e. local node-scope publications mustn't receive messages arriving
 * from another node, even if the multcast link brought it here)
 *
 * Returns non-zero if any off-node ports overlap
 */

int tipc_nametbl_mc_translate(u32 type, u32 lower, u32 upper, u32 limit,
			      struct tipc_port_list *dports)
{
	struct name_seq *seq;
	struct sub_seq *sseq;
	struct sub_seq *sseq_stop;
	struct name_info *info;
	int res = 0;

	read_lock_bh(&tipc_nametbl_lock);
	seq = nametbl_find_seq(type);
	if (!seq)
		goto exit;

	spin_lock_bh(&seq->lock);

	sseq = seq->sseqs + nameseq_locate_subseq(seq, lower);
	sseq_stop = seq->sseqs + seq->first_free;
	for (; sseq != sseq_stop; sseq++) {
		struct publication *publ;

		if (sseq->lower > upper)
			break;

		info = sseq->info;
		list_for_each_entry(publ, &info->node_list, node_list) {
			if (publ->scope <= limit)
				tipc_port_list_add(dports, publ->ref);
		}

		if (info->cluster_list_size != info->node_list_size)
			res = 1;
	}

	spin_unlock_bh(&seq->lock);
exit:
	read_unlock_bh(&tipc_nametbl_lock);
	return res;
}

/*
 * tipc_nametbl_publish - add name publication to network name tables
 */

struct publication *tipc_nametbl_publish(u32 type, u32 lower, u32 upper,
				    u32 scope, u32 port_ref, u32 key)
{
	struct publication *publ;

	if (table.local_publ_count >= tipc_max_publications) {
		warn("Publication failed, local publication limit reached (%u)\n",
		     tipc_max_publications);
		return NULL;
	}

	write_lock_bh(&tipc_nametbl_lock);
	publ = tipc_nametbl_insert_publ(type, lower, upper, scope,
				   tipc_own_addr, port_ref, key);
	if (likely(publ)) {
		table.local_publ_count++;
		tipc_named_publish(publ);
	}
	write_unlock_bh(&tipc_nametbl_lock);
	return publ;
}

/**
 * tipc_nametbl_withdraw - withdraw name publication from network name tables
 */

int tipc_nametbl_withdraw(u32 type, u32 lower, u32 ref, u32 key)
{
	struct publication *publ;

	write_lock_bh(&tipc_nametbl_lock);
	publ = tipc_nametbl_remove_publ(type, lower, tipc_own_addr, ref, key);
	if (likely(publ)) {
		table.local_publ_count--;
		tipc_named_withdraw(publ);
		write_unlock_bh(&tipc_nametbl_lock);
		list_del_init(&publ->pport_list);
		kfree(publ);
		return 1;
	}
	write_unlock_bh(&tipc_nametbl_lock);
	err("Unable to remove local publication\n"
	    "(type=%u, lower=%u, ref=%u, key=%u)\n",
	    type, lower, ref, key);
	return 0;
}

/**
 * tipc_nametbl_subscribe - add a subscription object to the name table
 */

void tipc_nametbl_subscribe(struct tipc_subscription *s)
{
	u32 type = s->seq.type;
	struct name_seq *seq;

	write_lock_bh(&tipc_nametbl_lock);
	seq = nametbl_find_seq(type);
	if (!seq)
		seq = tipc_nameseq_create(type, &table.types[hash(type)]);
	if (seq) {
		spin_lock_bh(&seq->lock);
		tipc_nameseq_subscribe(seq, s);
		spin_unlock_bh(&seq->lock);
	} else {
		warn("Failed to create subscription for {%u,%u,%u}\n",
		     s->seq.type, s->seq.lower, s->seq.upper);
	}
	write_unlock_bh(&tipc_nametbl_lock);
}

/**
 * tipc_nametbl_unsubscribe - remove a subscription object from name table
 */

void tipc_nametbl_unsubscribe(struct tipc_subscription *s)
{
	struct name_seq *seq;

	write_lock_bh(&tipc_nametbl_lock);
	seq = nametbl_find_seq(s->seq.type);
	if (seq != NULL) {
		spin_lock_bh(&seq->lock);
		list_del_init(&s->nameseq_list);
		spin_unlock_bh(&seq->lock);
		if ((seq->first_free == 0) && list_empty(&seq->subscriptions)) {
			hlist_del_init(&seq->ns_list);
			kfree(seq->sseqs);
			kfree(seq);
		}
	}
	write_unlock_bh(&tipc_nametbl_lock);
}


/**
 * subseq_list: print specified sub-sequence contents into the given buffer
 */

static void subseq_list(struct sub_seq *sseq, struct print_buf *buf, u32 depth,
			u32 index)
{
	char portIdStr[27];
	const char *scope_str[] = {"", " zone", " cluster", " node"};
	struct publication *publ;
	struct name_info *info;

	tipc_printf(buf, "%-10u %-10u ", sseq->lower, sseq->upper);

	if (depth == 2) {
		tipc_printf(buf, "\n");
		return;
	}

	info = sseq->info;

	list_for_each_entry(publ, &info->zone_list, zone_list) {
		sprintf(portIdStr, "<%u.%u.%u:%u>",
			 tipc_zone(publ->node), tipc_cluster(publ->node),
			 tipc_node(publ->node), publ->ref);
		tipc_printf(buf, "%-26s ", portIdStr);
		if (depth > 3) {
			tipc_printf(buf, "%-10u %s", publ->key,
				    scope_str[publ->scope]);
		}
		if (!list_is_last(&publ->zone_list, &info->zone_list))
			tipc_printf(buf, "\n%33s", " ");
	};

	tipc_printf(buf, "\n");
}

/**
 * nameseq_list: print specified name sequence contents into the given buffer
 */

static void nameseq_list(struct name_seq *seq, struct print_buf *buf, u32 depth,
			 u32 type, u32 lowbound, u32 upbound, u32 index)
{
	struct sub_seq *sseq;
	char typearea[11];

	if (seq->first_free == 0)
		return;

	sprintf(typearea, "%-10u", seq->type);

	if (depth == 1) {
		tipc_printf(buf, "%s\n", typearea);
		return;
	}

	for (sseq = seq->sseqs; sseq != &seq->sseqs[seq->first_free]; sseq++) {
		if ((lowbound <= sseq->upper) && (upbound >= sseq->lower)) {
			tipc_printf(buf, "%s ", typearea);
			spin_lock_bh(&seq->lock);
			subseq_list(sseq, buf, depth, index);
			spin_unlock_bh(&seq->lock);
			sprintf(typearea, "%10s", " ");
		}
	}
}

/**
 * nametbl_header - print name table header into the given buffer
 */

static void nametbl_header(struct print_buf *buf, u32 depth)
{
	const char *header[] = {
		"Type       ",
		"Lower      Upper      ",
		"Port Identity              ",
		"Publication Scope"
	};

	int i;

	if (depth > 4)
		depth = 4;
	for (i = 0; i < depth; i++)
		tipc_printf(buf, header[i]);
	tipc_printf(buf, "\n");
}

/**
 * nametbl_list - print specified name table contents into the given buffer
 */

static void nametbl_list(struct print_buf *buf, u32 depth_info,
			 u32 type, u32 lowbound, u32 upbound)
{
	struct hlist_head *seq_head;
	struct hlist_node *seq_node;
	struct name_seq *seq;
	int all_types;
	u32 depth;
	u32 i;

	all_types = (depth_info & TIPC_NTQ_ALLTYPES);
	depth = (depth_info & ~TIPC_NTQ_ALLTYPES);

	if (depth == 0)
		return;

	if (all_types) {
		/* display all entries in name table to specified depth */
		nametbl_header(buf, depth);
		lowbound = 0;
		upbound = ~0;
		for (i = 0; i < tipc_nametbl_size; i++) {
			seq_head = &table.types[i];
			hlist_for_each_entry(seq, seq_node, seq_head, ns_list) {
				nameseq_list(seq, buf, depth, seq->type,
					     lowbound, upbound, i);
			}
		}
	} else {
		/* display only the sequence that matches the specified type */
		if (upbound < lowbound) {
			tipc_printf(buf, "invalid name sequence specified\n");
			return;
		}
		nametbl_header(buf, depth);
		i = hash(type);
		seq_head = &table.types[i];
		hlist_for_each_entry(seq, seq_node, seq_head, ns_list) {
			if (seq->type == type) {
				nameseq_list(seq, buf, depth, type,
					     lowbound, upbound, i);
				break;
			}
		}
	}
}

#define MAX_NAME_TBL_QUERY 32768

struct sk_buff *tipc_nametbl_get(const void *req_tlv_area, int req_tlv_space)
{
	struct sk_buff *buf;
	struct tipc_name_table_query *argv;
	struct tlv_desc *rep_tlv;
	struct print_buf b;
	int str_len;

	if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_NAME_TBL_QUERY))
		return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);

	buf = tipc_cfg_reply_alloc(TLV_SPACE(MAX_NAME_TBL_QUERY));
	if (!buf)
		return NULL;

	rep_tlv = (struct tlv_desc *)buf->data;
	tipc_printbuf_init(&b, TLV_DATA(rep_tlv), MAX_NAME_TBL_QUERY);
	argv = (struct tipc_name_table_query *)TLV_DATA(req_tlv_area);
	read_lock_bh(&tipc_nametbl_lock);
	nametbl_list(&b, ntohl(argv->depth), ntohl(argv->type),
		     ntohl(argv->lowbound), ntohl(argv->upbound));
	read_unlock_bh(&tipc_nametbl_lock);
	str_len = tipc_printbuf_validate(&b);

	skb_put(buf, TLV_SPACE(str_len));
	TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);

	return buf;
}

int tipc_nametbl_init(void)
{
	table.types = kcalloc(tipc_nametbl_size, sizeof(struct hlist_head),
			      GFP_ATOMIC);
	if (!table.types)
		return -ENOMEM;

	table.local_publ_count = 0;
	return 0;
}

void tipc_nametbl_stop(void)
{
	u32 i;

	if (!table.types)
		return;

	/* Verify name table is empty, then release it */

	write_lock_bh(&tipc_nametbl_lock);
	for (i = 0; i < tipc_nametbl_size; i++) {
		if (!hlist_empty(&table.types[i]))
			err("tipc_nametbl_stop(): hash chain %u is non-null\n", i);
	}
	kfree(table.types);
	table.types = NULL;
	write_unlock_bh(&tipc_nametbl_lock);
}