Bootlin logo

Elixir Cross Referencer

  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
/* Copyright (C) 2008-2012 B.A.T.M.A.N. contributors:
 *
 * Simon Wunderlich
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA
 */

#include "main.h"
#include "send.h"
#include "translation-table.h"
#include "vis.h"
#include "soft-interface.h"
#include "hard-interface.h"
#include "hash.h"
#include "originator.h"

#define BATADV_MAX_VIS_PACKET_SIZE 1000

static void batadv_start_vis_timer(struct batadv_priv *bat_priv);

/* free the info */
static void batadv_free_info(struct kref *ref)
{
	struct batadv_vis_info *info;
	struct batadv_priv *bat_priv;
	struct batadv_recvlist_node *entry, *tmp;

	info = container_of(ref, struct batadv_vis_info, refcount);
	bat_priv = info->bat_priv;

	list_del_init(&info->send_list);
	spin_lock_bh(&bat_priv->vis.list_lock);
	list_for_each_entry_safe(entry, tmp, &info->recv_list, list) {
		list_del(&entry->list);
		kfree(entry);
	}

	spin_unlock_bh(&bat_priv->vis.list_lock);
	kfree_skb(info->skb_packet);
	kfree(info);
}

/* Compare two vis packets, used by the hashing algorithm */
static int batadv_vis_info_cmp(const struct hlist_node *node, const void *data2)
{
	const struct batadv_vis_info *d1, *d2;
	const struct batadv_vis_packet *p1, *p2;

	d1 = container_of(node, struct batadv_vis_info, hash_entry);
	d2 = data2;
	p1 = (struct batadv_vis_packet *)d1->skb_packet->data;
	p2 = (struct batadv_vis_packet *)d2->skb_packet->data;
	return batadv_compare_eth(p1->vis_orig, p2->vis_orig);
}

/* hash function to choose an entry in a hash table of given size
 * hash algorithm from http://en.wikipedia.org/wiki/Hash_table
 */
static uint32_t batadv_vis_info_choose(const void *data, uint32_t size)
{
	const struct batadv_vis_info *vis_info = data;
	const struct batadv_vis_packet *packet;
	const unsigned char *key;
	uint32_t hash = 0;
	size_t i;

	packet = (struct batadv_vis_packet *)vis_info->skb_packet->data;
	key = packet->vis_orig;
	for (i = 0; i < ETH_ALEN; i++) {
		hash += key[i];
		hash += (hash << 10);
		hash ^= (hash >> 6);
	}

	hash += (hash << 3);
	hash ^= (hash >> 11);
	hash += (hash << 15);

	return hash % size;
}

static struct batadv_vis_info *
batadv_vis_hash_find(struct batadv_priv *bat_priv, const void *data)
{
	struct batadv_hashtable *hash = bat_priv->vis.hash;
	struct hlist_head *head;
	struct hlist_node *node;
	struct batadv_vis_info *vis_info, *vis_info_tmp = NULL;
	uint32_t index;

	if (!hash)
		return NULL;

	index = batadv_vis_info_choose(data, hash->size);
	head = &hash->table[index];

	rcu_read_lock();
	hlist_for_each_entry_rcu(vis_info, node, head, hash_entry) {
		if (!batadv_vis_info_cmp(node, data))
			continue;

		vis_info_tmp = vis_info;
		break;
	}
	rcu_read_unlock();

	return vis_info_tmp;
}

/* insert interface to the list of interfaces of one originator, if it
 * does not already exist in the list
 */
static void batadv_vis_data_insert_interface(const uint8_t *interface,
					     struct hlist_head *if_list,
					     bool primary)
{
	struct batadv_if_list_entry *entry;
	struct hlist_node *pos;

	hlist_for_each_entry(entry, pos, if_list, list) {
		if (batadv_compare_eth(entry->addr, interface))
			return;
	}

	/* it's a new address, add it to the list */
	entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
	if (!entry)
		return;
	memcpy(entry->addr, interface, ETH_ALEN);
	entry->primary = primary;
	hlist_add_head(&entry->list, if_list);
}

static void batadv_vis_data_read_prim_sec(struct seq_file *seq,
					  const struct hlist_head *if_list)
{
	struct batadv_if_list_entry *entry;
	struct hlist_node *pos;

	hlist_for_each_entry(entry, pos, if_list, list) {
		if (entry->primary)
			seq_printf(seq, "PRIMARY, ");
		else
			seq_printf(seq,  "SEC %pM, ", entry->addr);
	}
}

/* read an entry  */
static ssize_t
batadv_vis_data_read_entry(struct seq_file *seq,
			   const struct batadv_vis_info_entry *entry,
			   const uint8_t *src, bool primary)
{
	if (primary && entry->quality == 0)
		return seq_printf(seq, "TT %pM, ", entry->dest);
	else if (batadv_compare_eth(entry->src, src))
		return seq_printf(seq, "TQ %pM %d, ", entry->dest,
				  entry->quality);

	return 0;
}

static void
batadv_vis_data_insert_interfaces(struct hlist_head *list,
				  struct batadv_vis_packet *packet,
				  struct batadv_vis_info_entry *entries)
{
	int i;

	for (i = 0; i < packet->entries; i++) {
		if (entries[i].quality == 0)
			continue;

		if (batadv_compare_eth(entries[i].src, packet->vis_orig))
			continue;

		batadv_vis_data_insert_interface(entries[i].src, list, false);
	}
}

static void batadv_vis_data_read_entries(struct seq_file *seq,
					 struct hlist_head *list,
					 struct batadv_vis_packet *packet,
					 struct batadv_vis_info_entry *entries)
{
	int i;
	struct batadv_if_list_entry *entry;
	struct hlist_node *pos;

	hlist_for_each_entry(entry, pos, list, list) {
		seq_printf(seq, "%pM,", entry->addr);

		for (i = 0; i < packet->entries; i++)
			batadv_vis_data_read_entry(seq, &entries[i],
						   entry->addr, entry->primary);

		/* add primary/secondary records */
		if (batadv_compare_eth(entry->addr, packet->vis_orig))
			batadv_vis_data_read_prim_sec(seq, list);

		seq_printf(seq, "\n");
	}
}

static void batadv_vis_seq_print_text_bucket(struct seq_file *seq,
					     const struct hlist_head *head)
{
	struct hlist_node *node;
	struct batadv_vis_info *info;
	struct batadv_vis_packet *packet;
	uint8_t *entries_pos;
	struct batadv_vis_info_entry *entries;
	struct batadv_if_list_entry *entry;
	struct hlist_node *pos, *n;

	HLIST_HEAD(vis_if_list);

	hlist_for_each_entry_rcu(info, node, head, hash_entry) {
		packet = (struct batadv_vis_packet *)info->skb_packet->data;
		entries_pos = (uint8_t *)packet + sizeof(*packet);
		entries = (struct batadv_vis_info_entry *)entries_pos;

		batadv_vis_data_insert_interface(packet->vis_orig, &vis_if_list,
						 true);
		batadv_vis_data_insert_interfaces(&vis_if_list, packet,
						  entries);
		batadv_vis_data_read_entries(seq, &vis_if_list, packet,
					     entries);

		hlist_for_each_entry_safe(entry, pos, n, &vis_if_list, list) {
			hlist_del(&entry->list);
			kfree(entry);
		}
	}
}

int batadv_vis_seq_print_text(struct seq_file *seq, void *offset)
{
	struct batadv_hard_iface *primary_if;
	struct hlist_head *head;
	struct net_device *net_dev = (struct net_device *)seq->private;
	struct batadv_priv *bat_priv = netdev_priv(net_dev);
	struct batadv_hashtable *hash = bat_priv->vis.hash;
	uint32_t i;
	int ret = 0;
	int vis_server = atomic_read(&bat_priv->vis_mode);

	primary_if = batadv_primary_if_get_selected(bat_priv);
	if (!primary_if)
		goto out;

	if (vis_server == BATADV_VIS_TYPE_CLIENT_UPDATE)
		goto out;

	spin_lock_bh(&bat_priv->vis.hash_lock);
	for (i = 0; i < hash->size; i++) {
		head = &hash->table[i];
		batadv_vis_seq_print_text_bucket(seq, head);
	}
	spin_unlock_bh(&bat_priv->vis.hash_lock);

out:
	if (primary_if)
		batadv_hardif_free_ref(primary_if);
	return ret;
}

/* add the info packet to the send list, if it was not
 * already linked in.
 */
static void batadv_send_list_add(struct batadv_priv *bat_priv,
				 struct batadv_vis_info *info)
{
	if (list_empty(&info->send_list)) {
		kref_get(&info->refcount);
		list_add_tail(&info->send_list, &bat_priv->vis.send_list);
	}
}

/* delete the info packet from the send list, if it was
 * linked in.
 */
static void batadv_send_list_del(struct batadv_vis_info *info)
{
	if (!list_empty(&info->send_list)) {
		list_del_init(&info->send_list);
		kref_put(&info->refcount, batadv_free_info);
	}
}

/* tries to add one entry to the receive list. */
static void batadv_recv_list_add(struct batadv_priv *bat_priv,
				 struct list_head *recv_list, const char *mac)
{
	struct batadv_recvlist_node *entry;

	entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
	if (!entry)
		return;

	memcpy(entry->mac, mac, ETH_ALEN);
	spin_lock_bh(&bat_priv->vis.list_lock);
	list_add_tail(&entry->list, recv_list);
	spin_unlock_bh(&bat_priv->vis.list_lock);
}

/* returns 1 if this mac is in the recv_list */
static int batadv_recv_list_is_in(struct batadv_priv *bat_priv,
				  const struct list_head *recv_list,
				  const char *mac)
{
	const struct batadv_recvlist_node *entry;

	spin_lock_bh(&bat_priv->vis.list_lock);
	list_for_each_entry(entry, recv_list, list) {
		if (batadv_compare_eth(entry->mac, mac)) {
			spin_unlock_bh(&bat_priv->vis.list_lock);
			return 1;
		}
	}
	spin_unlock_bh(&bat_priv->vis.list_lock);
	return 0;
}

/* try to add the packet to the vis_hash. return NULL if invalid (e.g. too old,
 * broken.. ).	vis hash must be locked outside.  is_new is set when the packet
 * is newer than old entries in the hash.
 */
static struct batadv_vis_info *
batadv_add_packet(struct batadv_priv *bat_priv,
		  struct batadv_vis_packet *vis_packet, int vis_info_len,
		  int *is_new, int make_broadcast)
{
	struct batadv_vis_info *info, *old_info;
	struct batadv_vis_packet *search_packet, *old_packet;
	struct batadv_vis_info search_elem;
	struct batadv_vis_packet *packet;
	struct sk_buff *tmp_skb;
	int hash_added;
	size_t len;
	size_t max_entries;

	*is_new = 0;
	/* sanity check */
	if (!bat_priv->vis.hash)
		return NULL;

	/* see if the packet is already in vis_hash */
	search_elem.skb_packet = dev_alloc_skb(sizeof(*search_packet));
	if (!search_elem.skb_packet)
		return NULL;
	len = sizeof(*search_packet);
	tmp_skb = search_elem.skb_packet;
	search_packet = (struct batadv_vis_packet *)skb_put(tmp_skb, len);

	memcpy(search_packet->vis_orig, vis_packet->vis_orig, ETH_ALEN);
	old_info = batadv_vis_hash_find(bat_priv, &search_elem);
	kfree_skb(search_elem.skb_packet);

	if (old_info) {
		tmp_skb = old_info->skb_packet;
		old_packet = (struct batadv_vis_packet *)tmp_skb->data;
		if (!batadv_seq_after(ntohl(vis_packet->seqno),
				      ntohl(old_packet->seqno))) {
			if (old_packet->seqno == vis_packet->seqno) {
				batadv_recv_list_add(bat_priv,
						     &old_info->recv_list,
						     vis_packet->sender_orig);
				return old_info;
			} else {
				/* newer packet is already in hash. */
				return NULL;
			}
		}
		/* remove old entry */
		batadv_hash_remove(bat_priv->vis.hash, batadv_vis_info_cmp,
				   batadv_vis_info_choose, old_info);
		batadv_send_list_del(old_info);
		kref_put(&old_info->refcount, batadv_free_info);
	}

	info = kmalloc(sizeof(*info), GFP_ATOMIC);
	if (!info)
		return NULL;

	len = sizeof(*packet) + vis_info_len;
	info->skb_packet = dev_alloc_skb(len + ETH_HLEN + NET_IP_ALIGN);
	if (!info->skb_packet) {
		kfree(info);
		return NULL;
	}
	skb_reserve(info->skb_packet, ETH_HLEN + NET_IP_ALIGN);
	packet = (struct batadv_vis_packet *)skb_put(info->skb_packet, len);

	kref_init(&info->refcount);
	INIT_LIST_HEAD(&info->send_list);
	INIT_LIST_HEAD(&info->recv_list);
	info->first_seen = jiffies;
	info->bat_priv = bat_priv;
	memcpy(packet, vis_packet, len);

	/* initialize and add new packet. */
	*is_new = 1;

	/* Make it a broadcast packet, if required */
	if (make_broadcast)
		memcpy(packet->target_orig, batadv_broadcast_addr, ETH_ALEN);

	/* repair if entries is longer than packet. */
	max_entries = vis_info_len / sizeof(struct batadv_vis_info_entry);
	if (packet->entries > max_entries)
		packet->entries = max_entries;

	batadv_recv_list_add(bat_priv, &info->recv_list, packet->sender_orig);

	/* try to add it */
	hash_added = batadv_hash_add(bat_priv->vis.hash, batadv_vis_info_cmp,
				     batadv_vis_info_choose, info,
				     &info->hash_entry);
	if (hash_added != 0) {
		/* did not work (for some reason) */
		kref_put(&info->refcount, batadv_free_info);
		info = NULL;
	}

	return info;
}

/* handle the server sync packet, forward if needed. */
void batadv_receive_server_sync_packet(struct batadv_priv *bat_priv,
				       struct batadv_vis_packet *vis_packet,
				       int vis_info_len)
{
	struct batadv_vis_info *info;
	int is_new, make_broadcast;
	int vis_server = atomic_read(&bat_priv->vis_mode);

	make_broadcast = (vis_server == BATADV_VIS_TYPE_SERVER_SYNC);

	spin_lock_bh(&bat_priv->vis.hash_lock);
	info = batadv_add_packet(bat_priv, vis_packet, vis_info_len,
				 &is_new, make_broadcast);
	if (!info)
		goto end;

	/* only if we are server ourselves and packet is newer than the one in
	 * hash.
	 */
	if (vis_server == BATADV_VIS_TYPE_SERVER_SYNC && is_new)
		batadv_send_list_add(bat_priv, info);
end:
	spin_unlock_bh(&bat_priv->vis.hash_lock);
}

/* handle an incoming client update packet and schedule forward if needed. */
void batadv_receive_client_update_packet(struct batadv_priv *bat_priv,
					 struct batadv_vis_packet *vis_packet,
					 int vis_info_len)
{
	struct batadv_vis_info *info;
	struct batadv_vis_packet *packet;
	int is_new;
	int vis_server = atomic_read(&bat_priv->vis_mode);
	int are_target = 0;

	/* clients shall not broadcast. */
	if (is_broadcast_ether_addr(vis_packet->target_orig))
		return;

	/* Are we the target for this VIS packet? */
	if (vis_server == BATADV_VIS_TYPE_SERVER_SYNC	&&
	    batadv_is_my_mac(vis_packet->target_orig))
		are_target = 1;

	spin_lock_bh(&bat_priv->vis.hash_lock);
	info = batadv_add_packet(bat_priv, vis_packet, vis_info_len,
				 &is_new, are_target);

	if (!info)
		goto end;
	/* note that outdated packets will be dropped at this point. */

	packet = (struct batadv_vis_packet *)info->skb_packet->data;

	/* send only if we're the target server or ... */
	if (are_target && is_new) {
		packet->vis_type = BATADV_VIS_TYPE_SERVER_SYNC;	/* upgrade! */
		batadv_send_list_add(bat_priv, info);

		/* ... we're not the recipient (and thus need to forward). */
	} else if (!batadv_is_my_mac(packet->target_orig)) {
		batadv_send_list_add(bat_priv, info);
	}

end:
	spin_unlock_bh(&bat_priv->vis.hash_lock);
}

/* Walk the originators and find the VIS server with the best tq. Set the packet
 * address to its address and return the best_tq.
 *
 * Must be called with the originator hash locked
 */
static int batadv_find_best_vis_server(struct batadv_priv *bat_priv,
				       struct batadv_vis_info *info)
{
	struct batadv_hashtable *hash = bat_priv->orig_hash;
	struct batadv_neigh_node *router;
	struct hlist_node *node;
	struct hlist_head *head;
	struct batadv_orig_node *orig_node;
	struct batadv_vis_packet *packet;
	int best_tq = -1;
	uint32_t i;

	packet = (struct batadv_vis_packet *)info->skb_packet->data;

	for (i = 0; i < hash->size; i++) {
		head = &hash->table[i];

		rcu_read_lock();
		hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {
			router = batadv_orig_node_get_router(orig_node);
			if (!router)
				continue;

			if ((orig_node->flags & BATADV_VIS_SERVER) &&
			    (router->tq_avg > best_tq)) {
				best_tq = router->tq_avg;
				memcpy(packet->target_orig, orig_node->orig,
				       ETH_ALEN);
			}
			batadv_neigh_node_free_ref(router);
		}
		rcu_read_unlock();
	}

	return best_tq;
}

/* Return true if the vis packet is full. */
static bool batadv_vis_packet_full(const struct batadv_vis_info *info)
{
	const struct batadv_vis_packet *packet;
	size_t num;

	packet = (struct batadv_vis_packet *)info->skb_packet->data;
	num = BATADV_MAX_VIS_PACKET_SIZE / sizeof(struct batadv_vis_info_entry);

	if (num < packet->entries + 1)
		return true;
	return false;
}

/* generates a packet of own vis data,
 * returns 0 on success, -1 if no packet could be generated
 */
static int batadv_generate_vis_packet(struct batadv_priv *bat_priv)
{
	struct batadv_hashtable *hash = bat_priv->orig_hash;
	struct hlist_node *node;
	struct hlist_head *head;
	struct batadv_orig_node *orig_node;
	struct batadv_neigh_node *router;
	struct batadv_vis_info *info = bat_priv->vis.my_info;
	struct batadv_vis_packet *packet;
	struct batadv_vis_info_entry *entry;
	struct batadv_tt_common_entry *tt_common_entry;
	uint8_t *packet_pos;
	int best_tq = -1;
	uint32_t i;

	info->first_seen = jiffies;
	packet = (struct batadv_vis_packet *)info->skb_packet->data;
	packet->vis_type = atomic_read(&bat_priv->vis_mode);

	memcpy(packet->target_orig, batadv_broadcast_addr, ETH_ALEN);
	packet->header.ttl = BATADV_TTL;
	packet->seqno = htonl(ntohl(packet->seqno) + 1);
	packet->entries = 0;
	packet->reserved = 0;
	skb_trim(info->skb_packet, sizeof(*packet));

	if (packet->vis_type == BATADV_VIS_TYPE_CLIENT_UPDATE) {
		best_tq = batadv_find_best_vis_server(bat_priv, info);

		if (best_tq < 0)
			return best_tq;
	}

	for (i = 0; i < hash->size; i++) {
		head = &hash->table[i];

		rcu_read_lock();
		hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {
			router = batadv_orig_node_get_router(orig_node);
			if (!router)
				continue;

			if (!batadv_compare_eth(router->addr, orig_node->orig))
				goto next;

			if (router->if_incoming->if_status != BATADV_IF_ACTIVE)
				goto next;

			if (router->tq_avg < 1)
				goto next;

			/* fill one entry into buffer. */
			packet_pos = skb_put(info->skb_packet, sizeof(*entry));
			entry = (struct batadv_vis_info_entry *)packet_pos;
			memcpy(entry->src,
			       router->if_incoming->net_dev->dev_addr,
			       ETH_ALEN);
			memcpy(entry->dest, orig_node->orig, ETH_ALEN);
			entry->quality = router->tq_avg;
			packet->entries++;

next:
			batadv_neigh_node_free_ref(router);

			if (batadv_vis_packet_full(info))
				goto unlock;
		}
		rcu_read_unlock();
	}

	hash = bat_priv->tt.local_hash;

	for (i = 0; i < hash->size; i++) {
		head = &hash->table[i];

		rcu_read_lock();
		hlist_for_each_entry_rcu(tt_common_entry, node, head,
					 hash_entry) {
			packet_pos = skb_put(info->skb_packet, sizeof(*entry));
			entry = (struct batadv_vis_info_entry *)packet_pos;
			memset(entry->src, 0, ETH_ALEN);
			memcpy(entry->dest, tt_common_entry->addr, ETH_ALEN);
			entry->quality = 0; /* 0 means TT */
			packet->entries++;

			if (batadv_vis_packet_full(info))
				goto unlock;
		}
		rcu_read_unlock();
	}

	return 0;

unlock:
	rcu_read_unlock();
	return 0;
}

/* free old vis packets. Must be called with this vis_hash_lock
 * held
 */
static void batadv_purge_vis_packets(struct batadv_priv *bat_priv)
{
	uint32_t i;
	struct batadv_hashtable *hash = bat_priv->vis.hash;
	struct hlist_node *node, *node_tmp;
	struct hlist_head *head;
	struct batadv_vis_info *info;

	for (i = 0; i < hash->size; i++) {
		head = &hash->table[i];

		hlist_for_each_entry_safe(info, node, node_tmp,
					  head, hash_entry) {
			/* never purge own data. */
			if (info == bat_priv->vis.my_info)
				continue;

			if (batadv_has_timed_out(info->first_seen,
						 BATADV_VIS_TIMEOUT)) {
				hlist_del(node);
				batadv_send_list_del(info);
				kref_put(&info->refcount, batadv_free_info);
			}
		}
	}
}

static void batadv_broadcast_vis_packet(struct batadv_priv *bat_priv,
					struct batadv_vis_info *info)
{
	struct batadv_hashtable *hash = bat_priv->orig_hash;
	struct hlist_node *node;
	struct hlist_head *head;
	struct batadv_orig_node *orig_node;
	struct batadv_vis_packet *packet;
	struct sk_buff *skb;
	uint32_t i;


	packet = (struct batadv_vis_packet *)info->skb_packet->data;

	/* send to all routers in range. */
	for (i = 0; i < hash->size; i++) {
		head = &hash->table[i];

		rcu_read_lock();
		hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) {
			/* if it's a vis server and reachable, send it. */
			if (!(orig_node->flags & BATADV_VIS_SERVER))
				continue;

			/* don't send it if we already received the packet from
			 * this node.
			 */
			if (batadv_recv_list_is_in(bat_priv, &info->recv_list,
						   orig_node->orig))
				continue;

			memcpy(packet->target_orig, orig_node->orig, ETH_ALEN);
			skb = skb_clone(info->skb_packet, GFP_ATOMIC);
			if (!skb)
				continue;

			if (!batadv_send_skb_to_orig(skb, orig_node, NULL))
				kfree_skb(skb);
		}
		rcu_read_unlock();
	}
}

static void batadv_unicast_vis_packet(struct batadv_priv *bat_priv,
				      struct batadv_vis_info *info)
{
	struct batadv_orig_node *orig_node;
	struct sk_buff *skb;
	struct batadv_vis_packet *packet;

	packet = (struct batadv_vis_packet *)info->skb_packet->data;

	orig_node = batadv_orig_hash_find(bat_priv, packet->target_orig);
	if (!orig_node)
		goto out;

	skb = skb_clone(info->skb_packet, GFP_ATOMIC);
	if (!skb)
		goto out;

	if (!batadv_send_skb_to_orig(skb, orig_node, NULL))
		kfree_skb(skb);

out:
	if (orig_node)
		batadv_orig_node_free_ref(orig_node);
}

/* only send one vis packet. called from batadv_send_vis_packets() */
static void batadv_send_vis_packet(struct batadv_priv *bat_priv,
				   struct batadv_vis_info *info)
{
	struct batadv_hard_iface *primary_if;
	struct batadv_vis_packet *packet;

	primary_if = batadv_primary_if_get_selected(bat_priv);
	if (!primary_if)
		goto out;

	packet = (struct batadv_vis_packet *)info->skb_packet->data;
	if (packet->header.ttl < 2) {
		pr_debug("Error - can't send vis packet: ttl exceeded\n");
		goto out;
	}

	memcpy(packet->sender_orig, primary_if->net_dev->dev_addr, ETH_ALEN);
	packet->header.ttl--;

	if (is_broadcast_ether_addr(packet->target_orig))
		batadv_broadcast_vis_packet(bat_priv, info);
	else
		batadv_unicast_vis_packet(bat_priv, info);
	packet->header.ttl++; /* restore TTL */

out:
	if (primary_if)
		batadv_hardif_free_ref(primary_if);
}

/* called from timer; send (and maybe generate) vis packet. */
static void batadv_send_vis_packets(struct work_struct *work)
{
	struct delayed_work *delayed_work;
	struct batadv_priv *bat_priv;
	struct batadv_priv_vis *priv_vis;
	struct batadv_vis_info *info;

	delayed_work = container_of(work, struct delayed_work, work);
	priv_vis = container_of(delayed_work, struct batadv_priv_vis, work);
	bat_priv = container_of(priv_vis, struct batadv_priv, vis);
	spin_lock_bh(&bat_priv->vis.hash_lock);
	batadv_purge_vis_packets(bat_priv);

	if (batadv_generate_vis_packet(bat_priv) == 0) {
		/* schedule if generation was successful */
		batadv_send_list_add(bat_priv, bat_priv->vis.my_info);
	}

	while (!list_empty(&bat_priv->vis.send_list)) {
		info = list_first_entry(&bat_priv->vis.send_list,
					typeof(*info), send_list);

		kref_get(&info->refcount);
		spin_unlock_bh(&bat_priv->vis.hash_lock);

		batadv_send_vis_packet(bat_priv, info);

		spin_lock_bh(&bat_priv->vis.hash_lock);
		batadv_send_list_del(info);
		kref_put(&info->refcount, batadv_free_info);
	}
	spin_unlock_bh(&bat_priv->vis.hash_lock);
	batadv_start_vis_timer(bat_priv);
}

/* init the vis server. this may only be called when if_list is already
 * initialized (e.g. bat0 is initialized, interfaces have been added)
 */
int batadv_vis_init(struct batadv_priv *bat_priv)
{
	struct batadv_vis_packet *packet;
	int hash_added;
	unsigned int len;
	unsigned long first_seen;
	struct sk_buff *tmp_skb;

	if (bat_priv->vis.hash)
		return 0;

	spin_lock_bh(&bat_priv->vis.hash_lock);

	bat_priv->vis.hash = batadv_hash_new(256);
	if (!bat_priv->vis.hash) {
		pr_err("Can't initialize vis_hash\n");
		goto err;
	}

	bat_priv->vis.my_info = kmalloc(BATADV_MAX_VIS_PACKET_SIZE, GFP_ATOMIC);
	if (!bat_priv->vis.my_info)
		goto err;

	len = sizeof(*packet) + BATADV_MAX_VIS_PACKET_SIZE;
	len += ETH_HLEN + NET_IP_ALIGN;
	bat_priv->vis.my_info->skb_packet = dev_alloc_skb(len);
	if (!bat_priv->vis.my_info->skb_packet)
		goto free_info;

	skb_reserve(bat_priv->vis.my_info->skb_packet, ETH_HLEN + NET_IP_ALIGN);
	tmp_skb = bat_priv->vis.my_info->skb_packet;
	packet = (struct batadv_vis_packet *)skb_put(tmp_skb, sizeof(*packet));

	/* prefill the vis info */
	first_seen = jiffies - msecs_to_jiffies(BATADV_VIS_INTERVAL);
	bat_priv->vis.my_info->first_seen = first_seen;
	INIT_LIST_HEAD(&bat_priv->vis.my_info->recv_list);
	INIT_LIST_HEAD(&bat_priv->vis.my_info->send_list);
	kref_init(&bat_priv->vis.my_info->refcount);
	bat_priv->vis.my_info->bat_priv = bat_priv;
	packet->header.version = BATADV_COMPAT_VERSION;
	packet->header.packet_type = BATADV_VIS;
	packet->header.ttl = BATADV_TTL;
	packet->seqno = 0;
	packet->reserved = 0;
	packet->entries = 0;

	INIT_LIST_HEAD(&bat_priv->vis.send_list);

	hash_added = batadv_hash_add(bat_priv->vis.hash, batadv_vis_info_cmp,
				     batadv_vis_info_choose,
				     bat_priv->vis.my_info,
				     &bat_priv->vis.my_info->hash_entry);
	if (hash_added != 0) {
		pr_err("Can't add own vis packet into hash\n");
		/* not in hash, need to remove it manually. */
		kref_put(&bat_priv->vis.my_info->refcount, batadv_free_info);
		goto err;
	}

	spin_unlock_bh(&bat_priv->vis.hash_lock);
	batadv_start_vis_timer(bat_priv);
	return 0;

free_info:
	kfree(bat_priv->vis.my_info);
	bat_priv->vis.my_info = NULL;
err:
	spin_unlock_bh(&bat_priv->vis.hash_lock);
	batadv_vis_quit(bat_priv);
	return -ENOMEM;
}

/* Decrease the reference count on a hash item info */
static void batadv_free_info_ref(struct hlist_node *node, void *arg)
{
	struct batadv_vis_info *info;

	info = container_of(node, struct batadv_vis_info, hash_entry);
	batadv_send_list_del(info);
	kref_put(&info->refcount, batadv_free_info);
}

/* shutdown vis-server */
void batadv_vis_quit(struct batadv_priv *bat_priv)
{
	if (!bat_priv->vis.hash)
		return;

	cancel_delayed_work_sync(&bat_priv->vis.work);

	spin_lock_bh(&bat_priv->vis.hash_lock);
	/* properly remove, kill timers ... */
	batadv_hash_delete(bat_priv->vis.hash, batadv_free_info_ref, NULL);
	bat_priv->vis.hash = NULL;
	bat_priv->vis.my_info = NULL;
	spin_unlock_bh(&bat_priv->vis.hash_lock);
}

/* schedule packets for (re)transmission */
static void batadv_start_vis_timer(struct batadv_priv *bat_priv)
{
	INIT_DELAYED_WORK(&bat_priv->vis.work, batadv_send_vis_packets);
	queue_delayed_work(batadv_event_workqueue, &bat_priv->vis.work,
			   msecs_to_jiffies(BATADV_VIS_INTERVAL));
}