summaryrefslogtreecommitdiff
path: root/net/batman-adv/main.c
blob: 548e405d13c100a144affa3a47e25675cc4bd119 (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
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
/* Copyright (C) 2007-2015 B.A.T.M.A.N. contributors:
 *
 * Marek Lindner, 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, see <http://www.gnu.org/licenses/>.
 */

#include <linux/crc32c.h>
#include <linux/highmem.h>
#include <linux/if_vlan.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <net/dsfield.h>
#include "main.h"
#include "sysfs.h"
#include "debugfs.h"
#include "routing.h"
#include "send.h"
#include "originator.h"
#include "soft-interface.h"
#include "icmp_socket.h"
#include "translation-table.h"
#include "hard-interface.h"
#include "gateway_client.h"
#include "bridge_loop_avoidance.h"
#include "distributed-arp-table.h"
#include "multicast.h"
#include "gateway_common.h"
#include "hash.h"
#include "bat_algo.h"
#include "network-coding.h"
#include "fragmentation.h"

/* List manipulations on hardif_list have to be rtnl_lock()'ed,
 * list traversals just rcu-locked
 */
struct list_head batadv_hardif_list;
static int (*batadv_rx_handler[256])(struct sk_buff *,
				     struct batadv_hard_iface *);
char batadv_routing_algo[20] = "BATMAN_IV";
static struct hlist_head batadv_algo_list;

unsigned char batadv_broadcast_addr[] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};

struct workqueue_struct *batadv_event_workqueue;

static void batadv_recv_handler_init(void);

static int __init batadv_init(void)
{
	INIT_LIST_HEAD(&batadv_hardif_list);
	INIT_HLIST_HEAD(&batadv_algo_list);

	batadv_recv_handler_init();

	batadv_iv_init();
	batadv_nc_init();

	batadv_event_workqueue = create_singlethread_workqueue("bat_events");

	if (!batadv_event_workqueue)
		return -ENOMEM;

	batadv_socket_init();
	batadv_debugfs_init();

	register_netdevice_notifier(&batadv_hard_if_notifier);
	rtnl_link_register(&batadv_link_ops);

	pr_info("B.A.T.M.A.N. advanced %s (compatibility version %i) loaded\n",
		BATADV_SOURCE_VERSION, BATADV_COMPAT_VERSION);

	return 0;
}

static void __exit batadv_exit(void)
{
	batadv_debugfs_destroy();
	rtnl_link_unregister(&batadv_link_ops);
	unregister_netdevice_notifier(&batadv_hard_if_notifier);
	batadv_hardif_remove_interfaces();

	flush_workqueue(batadv_event_workqueue);
	destroy_workqueue(batadv_event_workqueue);
	batadv_event_workqueue = NULL;

	rcu_barrier();
}

int batadv_mesh_init(struct net_device *soft_iface)
{
	struct batadv_priv *bat_priv = netdev_priv(soft_iface);
	int ret;

	spin_lock_init(&bat_priv->forw_bat_list_lock);
	spin_lock_init(&bat_priv->forw_bcast_list_lock);
	spin_lock_init(&bat_priv->tt.changes_list_lock);
	spin_lock_init(&bat_priv->tt.req_list_lock);
	spin_lock_init(&bat_priv->tt.roam_list_lock);
	spin_lock_init(&bat_priv->tt.last_changeset_lock);
	spin_lock_init(&bat_priv->tt.commit_lock);
	spin_lock_init(&bat_priv->gw.list_lock);
#ifdef CONFIG_BATMAN_ADV_MCAST
	spin_lock_init(&bat_priv->mcast.want_lists_lock);
#endif
	spin_lock_init(&bat_priv->tvlv.container_list_lock);
	spin_lock_init(&bat_priv->tvlv.handler_list_lock);
	spin_lock_init(&bat_priv->softif_vlan_list_lock);

	INIT_HLIST_HEAD(&bat_priv->forw_bat_list);
	INIT_HLIST_HEAD(&bat_priv->forw_bcast_list);
	INIT_HLIST_HEAD(&bat_priv->gw.list);
#ifdef CONFIG_BATMAN_ADV_MCAST
	INIT_HLIST_HEAD(&bat_priv->mcast.want_all_unsnoopables_list);
	INIT_HLIST_HEAD(&bat_priv->mcast.want_all_ipv4_list);
	INIT_HLIST_HEAD(&bat_priv->mcast.want_all_ipv6_list);
#endif
	INIT_LIST_HEAD(&bat_priv->tt.changes_list);
	INIT_LIST_HEAD(&bat_priv->tt.req_list);
	INIT_LIST_HEAD(&bat_priv->tt.roam_list);
#ifdef CONFIG_BATMAN_ADV_MCAST
	INIT_HLIST_HEAD(&bat_priv->mcast.mla_list);
#endif
	INIT_HLIST_HEAD(&bat_priv->tvlv.container_list);
	INIT_HLIST_HEAD(&bat_priv->tvlv.handler_list);
	INIT_HLIST_HEAD(&bat_priv->softif_vlan_list);

	ret = batadv_originator_init(bat_priv);
	if (ret < 0)
		goto err;

	ret = batadv_tt_init(bat_priv);
	if (ret < 0)
		goto err;

	ret = batadv_bla_init(bat_priv);
	if (ret < 0)
		goto err;

	ret = batadv_dat_init(bat_priv);
	if (ret < 0)
		goto err;

	ret = batadv_nc_mesh_init(bat_priv);
	if (ret < 0)
		goto err;

	batadv_gw_init(bat_priv);
	batadv_mcast_init(bat_priv);

	atomic_set(&bat_priv->gw.reselect, 0);
	atomic_set(&bat_priv->mesh_state, BATADV_MESH_ACTIVE);

	return 0;

err:
	batadv_mesh_free(soft_iface);
	return ret;
}

void batadv_mesh_free(struct net_device *soft_iface)
{
	struct batadv_priv *bat_priv = netdev_priv(soft_iface);

	atomic_set(&bat_priv->mesh_state, BATADV_MESH_DEACTIVATING);

	batadv_purge_outstanding_packets(bat_priv, NULL);

	batadv_gw_node_purge(bat_priv);
	batadv_nc_mesh_free(bat_priv);
	batadv_dat_free(bat_priv);
	batadv_bla_free(bat_priv);

	batadv_mcast_free(bat_priv);

	/* Free the TT and the originator tables only after having terminated
	 * all the other depending components which may use these structures for
	 * their purposes.
	 */
	batadv_tt_free(bat_priv);

	/* Since the originator table clean up routine is accessing the TT
	 * tables as well, it has to be invoked after the TT tables have been
	 * freed and marked as empty. This ensures that no cleanup RCU callbacks
	 * accessing the TT data are scheduled for later execution.
	 */
	batadv_originator_free(bat_priv);

	batadv_gw_free(bat_priv);

	free_percpu(bat_priv->bat_counters);
	bat_priv->bat_counters = NULL;

	atomic_set(&bat_priv->mesh_state, BATADV_MESH_INACTIVE);
}

/**
 * batadv_is_my_mac - check if the given mac address belongs to any of the real
 * interfaces in the current mesh
 * @bat_priv: the bat priv with all the soft interface information
 * @addr: the address to check
 *
 * Returns 'true' if the mac address was found, false otherwise.
 */
bool batadv_is_my_mac(struct batadv_priv *bat_priv, const uint8_t *addr)
{
	const struct batadv_hard_iface *hard_iface;
	bool is_my_mac = false;

	rcu_read_lock();
	list_for_each_entry_rcu(hard_iface, &batadv_hardif_list, list) {
		if (hard_iface->if_status != BATADV_IF_ACTIVE)
			continue;

		if (hard_iface->soft_iface != bat_priv->soft_iface)
			continue;

		if (batadv_compare_eth(hard_iface->net_dev->dev_addr, addr)) {
			is_my_mac = true;
			break;
		}
	}
	rcu_read_unlock();
	return is_my_mac;
}

/**
 * batadv_seq_print_text_primary_if_get - called from debugfs table printing
 *  function that requires the primary interface
 * @seq: debugfs table seq_file struct
 *
 * Returns primary interface if found or NULL otherwise.
 */
struct batadv_hard_iface *
batadv_seq_print_text_primary_if_get(struct seq_file *seq)
{
	struct net_device *net_dev = (struct net_device *)seq->private;
	struct batadv_priv *bat_priv = netdev_priv(net_dev);
	struct batadv_hard_iface *primary_if;

	primary_if = batadv_primary_if_get_selected(bat_priv);

	if (!primary_if) {
		seq_printf(seq,
			   "BATMAN mesh %s disabled - please specify interfaces to enable it\n",
			   net_dev->name);
		goto out;
	}

	if (primary_if->if_status == BATADV_IF_ACTIVE)
		goto out;

	seq_printf(seq,
		   "BATMAN mesh %s disabled - primary interface not active\n",
		   net_dev->name);
	batadv_hardif_free_ref(primary_if);
	primary_if = NULL;

out:
	return primary_if;
}

/**
 * batadv_max_header_len - calculate maximum encapsulation overhead for a
 *  payload packet
 *
 * Return the maximum encapsulation overhead in bytes.
 */
int batadv_max_header_len(void)
{
	int header_len = 0;

	header_len = max_t(int, header_len,
			   sizeof(struct batadv_unicast_packet));
	header_len = max_t(int, header_len,
			   sizeof(struct batadv_unicast_4addr_packet));
	header_len = max_t(int, header_len,
			   sizeof(struct batadv_bcast_packet));

#ifdef CONFIG_BATMAN_ADV_NC
	header_len = max_t(int, header_len,
			   sizeof(struct batadv_coded_packet));
#endif

	return header_len + ETH_HLEN;
}

/**
 * batadv_skb_set_priority - sets skb priority according to packet content
 * @skb: the packet to be sent
 * @offset: offset to the packet content
 *
 * This function sets a value between 256 and 263 (802.1d priority), which
 * can be interpreted by the cfg80211 or other drivers.
 */
void batadv_skb_set_priority(struct sk_buff *skb, int offset)
{
	struct iphdr ip_hdr_tmp, *ip_hdr;
	struct ipv6hdr ip6_hdr_tmp, *ip6_hdr;
	struct ethhdr ethhdr_tmp, *ethhdr;
	struct vlan_ethhdr *vhdr, vhdr_tmp;
	u32 prio;

	/* already set, do nothing */
	if (skb->priority >= 256 && skb->priority <= 263)
		return;

	ethhdr = skb_header_pointer(skb, offset, sizeof(*ethhdr), &ethhdr_tmp);
	if (!ethhdr)
		return;

	switch (ethhdr->h_proto) {
	case htons(ETH_P_8021Q):
		vhdr = skb_header_pointer(skb, offset + sizeof(*vhdr),
					  sizeof(*vhdr), &vhdr_tmp);
		if (!vhdr)
			return;
		prio = ntohs(vhdr->h_vlan_TCI) & VLAN_PRIO_MASK;
		prio = prio >> VLAN_PRIO_SHIFT;
		break;
	case htons(ETH_P_IP):
		ip_hdr = skb_header_pointer(skb, offset + sizeof(*ethhdr),
					    sizeof(*ip_hdr), &ip_hdr_tmp);
		if (!ip_hdr)
			return;
		prio = (ipv4_get_dsfield(ip_hdr) & 0xfc) >> 5;
		break;
	case htons(ETH_P_IPV6):
		ip6_hdr = skb_header_pointer(skb, offset + sizeof(*ethhdr),
					     sizeof(*ip6_hdr), &ip6_hdr_tmp);
		if (!ip6_hdr)
			return;
		prio = (ipv6_get_dsfield(ip6_hdr) & 0xfc) >> 5;
		break;
	default:
		return;
	}

	skb->priority = prio + 256;
}

static int batadv_recv_unhandled_packet(struct sk_buff *skb,
					struct batadv_hard_iface *recv_if)
{
	return NET_RX_DROP;
}

/* incoming packets with the batman ethertype received on any active hard
 * interface
 */
int batadv_batman_skb_recv(struct sk_buff *skb, struct net_device *dev,
			   struct packet_type *ptype,
			   struct net_device *orig_dev)
{
	struct batadv_priv *bat_priv;
	struct batadv_ogm_packet *batadv_ogm_packet;
	struct batadv_hard_iface *hard_iface;
	uint8_t idx;
	int ret;

	hard_iface = container_of(ptype, struct batadv_hard_iface,
				  batman_adv_ptype);
	skb = skb_share_check(skb, GFP_ATOMIC);

	/* skb was released by skb_share_check() */
	if (!skb)
		goto err_out;

	/* packet should hold at least type and version */
	if (unlikely(!pskb_may_pull(skb, 2)))
		goto err_free;

	/* expect a valid ethernet header here. */
	if (unlikely(skb->mac_len != ETH_HLEN || !skb_mac_header(skb)))
		goto err_free;

	if (!hard_iface->soft_iface)
		goto err_free;

	bat_priv = netdev_priv(hard_iface->soft_iface);

	if (atomic_read(&bat_priv->mesh_state) != BATADV_MESH_ACTIVE)
		goto err_free;

	/* discard frames on not active interfaces */
	if (hard_iface->if_status != BATADV_IF_ACTIVE)
		goto err_free;

	batadv_ogm_packet = (struct batadv_ogm_packet *)skb->data;

	if (batadv_ogm_packet->version != BATADV_COMPAT_VERSION) {
		batadv_dbg(BATADV_DBG_BATMAN, bat_priv,
			   "Drop packet: incompatible batman version (%i)\n",
			   batadv_ogm_packet->version);
		goto err_free;
	}

	/* reset control block to avoid left overs from previous users */
	memset(skb->cb, 0, sizeof(struct batadv_skb_cb));

	/* all receive handlers return whether they received or reused
	 * the supplied skb. if not, we have to free the skb.
	 */
	idx = batadv_ogm_packet->packet_type;
	ret = (*batadv_rx_handler[idx])(skb, hard_iface);

	if (ret == NET_RX_DROP)
		kfree_skb(skb);

	/* return NET_RX_SUCCESS in any case as we
	 * most probably dropped the packet for
	 * routing-logical reasons.
	 */
	return NET_RX_SUCCESS;

err_free:
	kfree_skb(skb);
err_out:
	return NET_RX_DROP;
}

static void batadv_recv_handler_init(void)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(batadv_rx_handler); i++)
		batadv_rx_handler[i] = batadv_recv_unhandled_packet;

	for (i = BATADV_UNICAST_MIN; i <= BATADV_UNICAST_MAX; i++)
		batadv_rx_handler[i] = batadv_recv_unhandled_unicast_packet;

	/* compile time checks for sizes */
	BUILD_BUG_ON(sizeof(struct batadv_bla_claim_dst) != 6);
	BUILD_BUG_ON(sizeof(struct batadv_ogm_packet) != 24);
	BUILD_BUG_ON(sizeof(struct batadv_icmp_header) != 20);
	BUILD_BUG_ON(sizeof(struct batadv_icmp_packet) != 20);
	BUILD_BUG_ON(sizeof(struct batadv_icmp_packet_rr) != 116);
	BUILD_BUG_ON(sizeof(struct batadv_unicast_packet) != 10);
	BUILD_BUG_ON(sizeof(struct batadv_unicast_4addr_packet) != 18);
	BUILD_BUG_ON(sizeof(struct batadv_frag_packet) != 20);
	BUILD_BUG_ON(sizeof(struct batadv_bcast_packet) != 14);
	BUILD_BUG_ON(sizeof(struct batadv_coded_packet) != 46);
	BUILD_BUG_ON(sizeof(struct batadv_unicast_tvlv_packet) != 20);
	BUILD_BUG_ON(sizeof(struct batadv_tvlv_hdr) != 4);
	BUILD_BUG_ON(sizeof(struct batadv_tvlv_gateway_data) != 8);
	BUILD_BUG_ON(sizeof(struct batadv_tvlv_tt_vlan_data) != 8);
	BUILD_BUG_ON(sizeof(struct batadv_tvlv_tt_change) != 12);
	BUILD_BUG_ON(sizeof(struct batadv_tvlv_roam_adv) != 8);

	/* broadcast packet */
	batadv_rx_handler[BATADV_BCAST] = batadv_recv_bcast_packet;

	/* unicast packets ... */
	/* unicast with 4 addresses packet */
	batadv_rx_handler[BATADV_UNICAST_4ADDR] = batadv_recv_unicast_packet;
	/* unicast packet */
	batadv_rx_handler[BATADV_UNICAST] = batadv_recv_unicast_packet;
	/* unicast tvlv packet */
	batadv_rx_handler[BATADV_UNICAST_TVLV] = batadv_recv_unicast_tvlv;
	/* batman icmp packet */
	batadv_rx_handler[BATADV_ICMP] = batadv_recv_icmp_packet;
	/* Fragmented packets */
	batadv_rx_handler[BATADV_UNICAST_FRAG] = batadv_recv_frag_packet;
}

int
batadv_recv_handler_register(uint8_t packet_type,
			     int (*recv_handler)(struct sk_buff *,
						 struct batadv_hard_iface *))
{
	int (*curr)(struct sk_buff *,
		    struct batadv_hard_iface *);
	curr = batadv_rx_handler[packet_type];

	if ((curr != batadv_recv_unhandled_packet) &&
	    (curr != batadv_recv_unhandled_unicast_packet))
		return -EBUSY;

	batadv_rx_handler[packet_type] = recv_handler;
	return 0;
}

void batadv_recv_handler_unregister(uint8_t packet_type)
{
	batadv_rx_handler[packet_type] = batadv_recv_unhandled_packet;
}

static struct batadv_algo_ops *batadv_algo_get(char *name)
{
	struct batadv_algo_ops *bat_algo_ops = NULL, *bat_algo_ops_tmp;

	hlist_for_each_entry(bat_algo_ops_tmp, &batadv_algo_list, list) {
		if (strcmp(bat_algo_ops_tmp->name, name) != 0)
			continue;

		bat_algo_ops = bat_algo_ops_tmp;
		break;
	}

	return bat_algo_ops;
}

int batadv_algo_register(struct batadv_algo_ops *bat_algo_ops)
{
	struct batadv_algo_ops *bat_algo_ops_tmp;

	bat_algo_ops_tmp = batadv_algo_get(bat_algo_ops->name);
	if (bat_algo_ops_tmp) {
		pr_info("Trying to register already registered routing algorithm: %s\n",
			bat_algo_ops->name);
		return -EEXIST;
	}

	/* all algorithms must implement all ops (for now) */
	if (!bat_algo_ops->bat_iface_enable ||
	    !bat_algo_ops->bat_iface_disable ||
	    !bat_algo_ops->bat_iface_update_mac ||
	    !bat_algo_ops->bat_primary_iface_set ||
	    !bat_algo_ops->bat_ogm_schedule ||
	    !bat_algo_ops->bat_ogm_emit ||
	    !bat_algo_ops->bat_neigh_cmp ||
	    !bat_algo_ops->bat_neigh_is_equiv_or_better) {
		pr_info("Routing algo '%s' does not implement required ops\n",
			bat_algo_ops->name);
		return -EINVAL;
	}

	INIT_HLIST_NODE(&bat_algo_ops->list);
	hlist_add_head(&bat_algo_ops->list, &batadv_algo_list);

	return 0;
}

int batadv_algo_select(struct batadv_priv *bat_priv, char *name)
{
	struct batadv_algo_ops *bat_algo_ops;

	bat_algo_ops = batadv_algo_get(name);
	if (!bat_algo_ops)
		return -EINVAL;

	bat_priv->bat_algo_ops = bat_algo_ops;

	return 0;
}

int batadv_algo_seq_print_text(struct seq_file *seq, void *offset)
{
	struct batadv_algo_ops *bat_algo_ops;

	seq_puts(seq, "Available routing algorithms:\n");

	hlist_for_each_entry(bat_algo_ops, &batadv_algo_list, list) {
		seq_printf(seq, "%s\n", bat_algo_ops->name);
	}

	return 0;
}

/**
 * batadv_skb_crc32 - calculate CRC32 of the whole packet and skip bytes in
 *  the header
 * @skb: skb pointing to fragmented socket buffers
 * @payload_ptr: Pointer to position inside the head buffer of the skb
 *  marking the start of the data to be CRC'ed
 *
 * payload_ptr must always point to an address in the skb head buffer and not to
 * a fragment.
 */
__be32 batadv_skb_crc32(struct sk_buff *skb, u8 *payload_ptr)
{
	u32 crc = 0;
	unsigned int from;
	unsigned int to = skb->len;
	struct skb_seq_state st;
	const u8 *data;
	unsigned int len;
	unsigned int consumed = 0;

	from = (unsigned int)(payload_ptr - skb->data);

	skb_prepare_seq_read(skb, from, to, &st);
	while ((len = skb_seq_read(consumed, &data, &st)) != 0) {
		crc = crc32c(crc, data, len);
		consumed += len;
	}

	return htonl(crc);
}

/**
 * batadv_tvlv_handler_free_ref - decrement the tvlv handler refcounter and
 *  possibly free it
 * @tvlv_handler: the tvlv handler to free
 */
static void
batadv_tvlv_handler_free_ref(struct batadv_tvlv_handler *tvlv_handler)
{
	if (atomic_dec_and_test(&tvlv_handler->refcount))
		kfree_rcu(tvlv_handler, rcu);
}

/**
 * batadv_tvlv_handler_get - retrieve tvlv handler from the tvlv handler list
 *  based on the provided type and version (both need to match)
 * @bat_priv: the bat priv with all the soft interface information
 * @type: tvlv handler type to look for
 * @version: tvlv handler version to look for
 *
 * Returns tvlv handler if found or NULL otherwise.
 */
static struct batadv_tvlv_handler
*batadv_tvlv_handler_get(struct batadv_priv *bat_priv,
			 uint8_t type, uint8_t version)
{
	struct batadv_tvlv_handler *tvlv_handler_tmp, *tvlv_handler = NULL;

	rcu_read_lock();
	hlist_for_each_entry_rcu(tvlv_handler_tmp,
				 &bat_priv->tvlv.handler_list, list) {
		if (tvlv_handler_tmp->type != type)
			continue;

		if (tvlv_handler_tmp->version != version)
			continue;

		if (!atomic_inc_not_zero(&tvlv_handler_tmp->refcount))
			continue;

		tvlv_handler = tvlv_handler_tmp;
		break;
	}
	rcu_read_unlock();

	return tvlv_handler;
}

/**
 * batadv_tvlv_container_free_ref - decrement the tvlv container refcounter and
 *  possibly free it
 * @tvlv: the tvlv container to free
 */
static void batadv_tvlv_container_free_ref(struct batadv_tvlv_container *tvlv)
{
	if (atomic_dec_and_test(&tvlv->refcount))
		kfree(tvlv);
}

/**
 * batadv_tvlv_container_get - retrieve tvlv container from the tvlv container
 *  list based on the provided type and version (both need to match)
 * @bat_priv: the bat priv with all the soft interface information
 * @type: tvlv container type to look for
 * @version: tvlv container version to look for
 *
 * Has to be called with the appropriate locks being acquired
 * (tvlv.container_list_lock).
 *
 * Returns tvlv container if found or NULL otherwise.
 */
static struct batadv_tvlv_container
*batadv_tvlv_container_get(struct batadv_priv *bat_priv,
			   uint8_t type, uint8_t version)
{
	struct batadv_tvlv_container *tvlv_tmp, *tvlv = NULL;

	hlist_for_each_entry(tvlv_tmp, &bat_priv->tvlv.container_list, list) {
		if (tvlv_tmp->tvlv_hdr.type != type)
			continue;

		if (tvlv_tmp->tvlv_hdr.version != version)
			continue;

		if (!atomic_inc_not_zero(&tvlv_tmp->refcount))
			continue;

		tvlv = tvlv_tmp;
		break;
	}

	return tvlv;
}

/**
 * batadv_tvlv_container_list_size - calculate the size of the tvlv container
 *  list entries
 * @bat_priv: the bat priv with all the soft interface information
 *
 * Has to be called with the appropriate locks being acquired
 * (tvlv.container_list_lock).
 *
 * Returns size of all currently registered tvlv containers in bytes.
 */
static uint16_t batadv_tvlv_container_list_size(struct batadv_priv *bat_priv)
{
	struct batadv_tvlv_container *tvlv;
	uint16_t tvlv_len = 0;

	hlist_for_each_entry(tvlv, &bat_priv->tvlv.container_list, list) {
		tvlv_len += sizeof(struct batadv_tvlv_hdr);
		tvlv_len += ntohs(tvlv->tvlv_hdr.len);
	}

	return tvlv_len;
}

/**
 * batadv_tvlv_container_remove - remove tvlv container from the tvlv container
 *  list
 * @tvlv: the to be removed tvlv container
 *
 * Has to be called with the appropriate locks being acquired
 * (tvlv.container_list_lock).
 */
static void batadv_tvlv_container_remove(struct batadv_tvlv_container *tvlv)
{
	if (!tvlv)
		return;

	hlist_del(&tvlv->list);

	/* first call to decrement the counter, second call to free */
	batadv_tvlv_container_free_ref(tvlv);
	batadv_tvlv_container_free_ref(tvlv);
}

/**
 * batadv_tvlv_container_unregister - unregister tvlv container based on the
 *  provided type and version (both need to match)
 * @bat_priv: the bat priv with all the soft interface information
 * @type: tvlv container type to unregister
 * @version: tvlv container type to unregister
 */
void batadv_tvlv_container_unregister(struct batadv_priv *bat_priv,
				      uint8_t type, uint8_t version)
{
	struct batadv_tvlv_container *tvlv;

	spin_lock_bh(&bat_priv->tvlv.container_list_lock);
	tvlv = batadv_tvlv_container_get(bat_priv, type, version);
	batadv_tvlv_container_remove(tvlv);
	spin_unlock_bh(&bat_priv->tvlv.container_list_lock);
}

/**
 * batadv_tvlv_container_register - register tvlv type, version and content
 *  to be propagated with each (primary interface) OGM
 * @bat_priv: the bat priv with all the soft interface information
 * @type: tvlv container type
 * @version: tvlv container version
 * @tvlv_value: tvlv container content
 * @tvlv_value_len: tvlv container content length
 *
 * If a container of the same type and version was already registered the new
 * content is going to replace the old one.
 */
void batadv_tvlv_container_register(struct batadv_priv *bat_priv,
				    uint8_t type, uint8_t version,
				    void *tvlv_value, uint16_t tvlv_value_len)
{
	struct batadv_tvlv_container *tvlv_old, *tvlv_new;

	if (!tvlv_value)
		tvlv_value_len = 0;

	tvlv_new = kzalloc(sizeof(*tvlv_new) + tvlv_value_len, GFP_ATOMIC);
	if (!tvlv_new)
		return;

	tvlv_new->tvlv_hdr.version = version;
	tvlv_new->tvlv_hdr.type = type;
	tvlv_new->tvlv_hdr.len = htons(tvlv_value_len);

	memcpy(tvlv_new + 1, tvlv_value, ntohs(tvlv_new->tvlv_hdr.len));
	INIT_HLIST_NODE(&tvlv_new->list);
	atomic_set(&tvlv_new->refcount, 1);

	spin_lock_bh(&bat_priv->tvlv.container_list_lock);
	tvlv_old = batadv_tvlv_container_get(bat_priv, type, version);
	batadv_tvlv_container_remove(tvlv_old);
	hlist_add_head(&tvlv_new->list, &bat_priv->tvlv.container_list);
	spin_unlock_bh(&bat_priv->tvlv.container_list_lock);
}

/**
 * batadv_tvlv_realloc_packet_buff - reallocate packet buffer to accommodate
 *  requested packet size
 * @packet_buff: packet buffer
 * @packet_buff_len: packet buffer size
 * @min_packet_len: requested packet minimum size
 * @additional_packet_len: requested additional packet size on top of minimum
 *  size
 *
 * Returns true of the packet buffer could be changed to the requested size,
 * false otherwise.
 */
static bool batadv_tvlv_realloc_packet_buff(unsigned char **packet_buff,
					    int *packet_buff_len,
					    int min_packet_len,
					    int additional_packet_len)
{
	unsigned char *new_buff;

	new_buff = kmalloc(min_packet_len + additional_packet_len, GFP_ATOMIC);

	/* keep old buffer if kmalloc should fail */
	if (!new_buff)
		return false;

	memcpy(new_buff, *packet_buff, min_packet_len);
	kfree(*packet_buff);
	*packet_buff = new_buff;
	*packet_buff_len = min_packet_len + additional_packet_len;

	return true;
}

/**
 * batadv_tvlv_container_ogm_append - append tvlv container content to given
 *  OGM packet buffer
 * @bat_priv: the bat priv with all the soft interface information
 * @packet_buff: ogm packet buffer
 * @packet_buff_len: ogm packet buffer size including ogm header and tvlv
 *  content
 * @packet_min_len: ogm header size to be preserved for the OGM itself
 *
 * The ogm packet might be enlarged or shrunk depending on the current size
 * and the size of the to-be-appended tvlv containers.
 *
 * Returns size of all appended tvlv containers in bytes.
 */
uint16_t batadv_tvlv_container_ogm_append(struct batadv_priv *bat_priv,
					  unsigned char **packet_buff,
					  int *packet_buff_len,
					  int packet_min_len)
{
	struct batadv_tvlv_container *tvlv;
	struct batadv_tvlv_hdr *tvlv_hdr;
	uint16_t tvlv_value_len;
	void *tvlv_value;
	bool ret;

	spin_lock_bh(&bat_priv->tvlv.container_list_lock);
	tvlv_value_len = batadv_tvlv_container_list_size(bat_priv);

	ret = batadv_tvlv_realloc_packet_buff(packet_buff, packet_buff_len,
					      packet_min_len, tvlv_value_len);

	if (!ret)
		goto end;

	if (!tvlv_value_len)
		goto end;

	tvlv_value = (*packet_buff) + packet_min_len;

	hlist_for_each_entry(tvlv, &bat_priv->tvlv.container_list, list) {
		tvlv_hdr = tvlv_value;
		tvlv_hdr->type = tvlv->tvlv_hdr.type;
		tvlv_hdr->version = tvlv->tvlv_hdr.version;
		tvlv_hdr->len = tvlv->tvlv_hdr.len;
		tvlv_value = tvlv_hdr + 1;
		memcpy(tvlv_value, tvlv + 1, ntohs(tvlv->tvlv_hdr.len));
		tvlv_value = (uint8_t *)tvlv_value + ntohs(tvlv->tvlv_hdr.len);
	}

end:
	spin_unlock_bh(&bat_priv->tvlv.container_list_lock);
	return tvlv_value_len;
}

/**
 * batadv_tvlv_call_handler - parse the given tvlv buffer to call the
 *  appropriate handlers
 * @bat_priv: the bat priv with all the soft interface information
 * @tvlv_handler: tvlv callback function handling the tvlv content
 * @ogm_source: flag indicating wether the tvlv is an ogm or a unicast packet
 * @orig_node: orig node emitting the ogm packet
 * @src: source mac address of the unicast packet
 * @dst: destination mac address of the unicast packet
 * @tvlv_value: tvlv content
 * @tvlv_value_len: tvlv content length
 *
 * Returns success if handler was not found or the return value of the handler
 * callback.
 */
static int batadv_tvlv_call_handler(struct batadv_priv *bat_priv,
				    struct batadv_tvlv_handler *tvlv_handler,
				    bool ogm_source,
				    struct batadv_orig_node *orig_node,
				    uint8_t *src, uint8_t *dst,
				    void *tvlv_value, uint16_t tvlv_value_len)
{
	if (!tvlv_handler)
		return NET_RX_SUCCESS;

	if (ogm_source) {
		if (!tvlv_handler->ogm_handler)
			return NET_RX_SUCCESS;

		if (!orig_node)
			return NET_RX_SUCCESS;

		tvlv_handler->ogm_handler(bat_priv, orig_node,
					  BATADV_NO_FLAGS,
					  tvlv_value, tvlv_value_len);
		tvlv_handler->flags |= BATADV_TVLV_HANDLER_OGM_CALLED;
	} else {
		if (!src)
			return NET_RX_SUCCESS;

		if (!dst)
			return NET_RX_SUCCESS;

		if (!tvlv_handler->unicast_handler)
			return NET_RX_SUCCESS;

		return tvlv_handler->unicast_handler(bat_priv, src,
						     dst, tvlv_value,
						     tvlv_value_len);
	}

	return NET_RX_SUCCESS;
}

/**
 * batadv_tvlv_containers_process - parse the given tvlv buffer to call the
 *  appropriate handlers
 * @bat_priv: the bat priv with all the soft interface information
 * @ogm_source: flag indicating wether the tvlv is an ogm or a unicast packet
 * @orig_node: orig node emitting the ogm packet
 * @src: source mac address of the unicast packet
 * @dst: destination mac address of the unicast packet
 * @tvlv_value: tvlv content
 * @tvlv_value_len: tvlv content length
 *
 * Returns success when processing an OGM or the return value of all called
 * handler callbacks.
 */
int batadv_tvlv_containers_process(struct batadv_priv *bat_priv,
				   bool ogm_source,
				   struct batadv_orig_node *orig_node,
				   uint8_t *src, uint8_t *dst,
				   void *tvlv_value, uint16_t tvlv_value_len)
{
	struct batadv_tvlv_handler *tvlv_handler;
	struct batadv_tvlv_hdr *tvlv_hdr;
	uint16_t tvlv_value_cont_len;
	uint8_t cifnotfound = BATADV_TVLV_HANDLER_OGM_CIFNOTFND;
	int ret = NET_RX_SUCCESS;

	while (tvlv_value_len >= sizeof(*tvlv_hdr)) {
		tvlv_hdr = tvlv_value;
		tvlv_value_cont_len = ntohs(tvlv_hdr->len);
		tvlv_value = tvlv_hdr + 1;
		tvlv_value_len -= sizeof(*tvlv_hdr);

		if (tvlv_value_cont_len > tvlv_value_len)
			break;

		tvlv_handler = batadv_tvlv_handler_get(bat_priv,
						       tvlv_hdr->type,
						       tvlv_hdr->version);

		ret |= batadv_tvlv_call_handler(bat_priv, tvlv_handler,
						ogm_source, orig_node,
						src, dst, tvlv_value,
						tvlv_value_cont_len);
		if (tvlv_handler)
			batadv_tvlv_handler_free_ref(tvlv_handler);
		tvlv_value = (uint8_t *)tvlv_value + tvlv_value_cont_len;
		tvlv_value_len -= tvlv_value_cont_len;
	}

	if (!ogm_source)
		return ret;

	rcu_read_lock();
	hlist_for_each_entry_rcu(tvlv_handler,
				 &bat_priv->tvlv.handler_list, list) {
		if ((tvlv_handler->flags & BATADV_TVLV_HANDLER_OGM_CIFNOTFND) &&
		    !(tvlv_handler->flags & BATADV_TVLV_HANDLER_OGM_CALLED))
			tvlv_handler->ogm_handler(bat_priv, orig_node,
						  cifnotfound, NULL, 0);

		tvlv_handler->flags &= ~BATADV_TVLV_HANDLER_OGM_CALLED;
	}
	rcu_read_unlock();

	return NET_RX_SUCCESS;
}

/**
 * batadv_tvlv_ogm_receive - process an incoming ogm and call the appropriate
 *  handlers
 * @bat_priv: the bat priv with all the soft interface information
 * @batadv_ogm_packet: ogm packet containing the tvlv containers
 * @orig_node: orig node emitting the ogm packet
 */
void batadv_tvlv_ogm_receive(struct batadv_priv *bat_priv,
			     struct batadv_ogm_packet *batadv_ogm_packet,
			     struct batadv_orig_node *orig_node)
{
	void *tvlv_value;
	uint16_t tvlv_value_len;

	if (!batadv_ogm_packet)
		return;

	tvlv_value_len = ntohs(batadv_ogm_packet->tvlv_len);
	if (!tvlv_value_len)
		return;

	tvlv_value = batadv_ogm_packet + 1;

	batadv_tvlv_containers_process(bat_priv, true, orig_node, NULL, NULL,
				       tvlv_value, tvlv_value_len);
}

/**
 * batadv_tvlv_handler_register - register tvlv handler based on the provided
 *  type and version (both need to match) for ogm tvlv payload and/or unicast
 *  payload
 * @bat_priv: the bat priv with all the soft interface information
 * @optr: ogm tvlv handler callback function. This function receives the orig
 *  node, flags and the tvlv content as argument to process.
 * @uptr: unicast tvlv handler callback function. This function receives the
 *  source & destination of the unicast packet as well as the tvlv content
 *  to process.
 * @type: tvlv handler type to be registered
 * @version: tvlv handler version to be registered
 * @flags: flags to enable or disable TVLV API behavior
 */
void batadv_tvlv_handler_register(struct batadv_priv *bat_priv,
				  void (*optr)(struct batadv_priv *bat_priv,
					       struct batadv_orig_node *orig,
					       uint8_t flags,
					       void *tvlv_value,
					       uint16_t tvlv_value_len),
				  int (*uptr)(struct batadv_priv *bat_priv,
					      uint8_t *src, uint8_t *dst,
					      void *tvlv_value,
					      uint16_t tvlv_value_len),
				  uint8_t type, uint8_t version, uint8_t flags)
{
	struct batadv_tvlv_handler *tvlv_handler;

	tvlv_handler = batadv_tvlv_handler_get(bat_priv, type, version);
	if (tvlv_handler) {
		batadv_tvlv_handler_free_ref(tvlv_handler);
		return;
	}

	tvlv_handler = kzalloc(sizeof(*tvlv_handler), GFP_ATOMIC);
	if (!tvlv_handler)
		return;

	tvlv_handler->ogm_handler = optr;
	tvlv_handler->unicast_handler = uptr;
	tvlv_handler->type = type;
	tvlv_handler->version = version;
	tvlv_handler->flags = flags;
	atomic_set(&tvlv_handler->refcount, 1);
	INIT_HLIST_NODE(&tvlv_handler->list);

	spin_lock_bh(&bat_priv->tvlv.handler_list_lock);
	hlist_add_head_rcu(&tvlv_handler->list, &bat_priv->tvlv.handler_list);
	spin_unlock_bh(&bat_priv->tvlv.handler_list_lock);
}

/**
 * batadv_tvlv_handler_unregister - unregister tvlv handler based on the
 *  provided type and version (both need to match)
 * @bat_priv: the bat priv with all the soft interface information
 * @type: tvlv handler type to be unregistered
 * @version: tvlv handler version to be unregistered
 */
void batadv_tvlv_handler_unregister(struct batadv_priv *bat_priv,
				    uint8_t type, uint8_t version)
{
	struct batadv_tvlv_handler *tvlv_handler;

	tvlv_handler = batadv_tvlv_handler_get(bat_priv, type, version);
	if (!tvlv_handler)
		return;

	batadv_tvlv_handler_free_ref(tvlv_handler);
	spin_lock_bh(&bat_priv->tvlv.handler_list_lock);
	hlist_del_rcu(&tvlv_handler->list);
	spin_unlock_bh(&bat_priv->tvlv.handler_list_lock);
	batadv_tvlv_handler_free_ref(tvlv_handler);
}

/**
 * batadv_tvlv_unicast_send - send a unicast packet with tvlv payload to the
 *  specified host
 * @bat_priv: the bat priv with all the soft interface information
 * @src: source mac address of the unicast packet
 * @dst: destination mac address of the unicast packet
 * @type: tvlv type
 * @version: tvlv version
 * @tvlv_value: tvlv content
 * @tvlv_value_len: tvlv content length
 */
void batadv_tvlv_unicast_send(struct batadv_priv *bat_priv, uint8_t *src,
			      uint8_t *dst, uint8_t type, uint8_t version,
			      void *tvlv_value, uint16_t tvlv_value_len)
{
	struct batadv_unicast_tvlv_packet *unicast_tvlv_packet;
	struct batadv_tvlv_hdr *tvlv_hdr;
	struct batadv_orig_node *orig_node;
	struct sk_buff *skb = NULL;
	unsigned char *tvlv_buff;
	unsigned int tvlv_len;
	ssize_t hdr_len = sizeof(*unicast_tvlv_packet);
	bool ret = false;

	orig_node = batadv_orig_hash_find(bat_priv, dst);
	if (!orig_node)
		goto out;

	tvlv_len = sizeof(*tvlv_hdr) + tvlv_value_len;

	skb = netdev_alloc_skb_ip_align(NULL, ETH_HLEN + hdr_len + tvlv_len);
	if (!skb)
		goto out;

	skb->priority = TC_PRIO_CONTROL;
	skb_reserve(skb, ETH_HLEN);
	tvlv_buff = skb_put(skb, sizeof(*unicast_tvlv_packet) + tvlv_len);
	unicast_tvlv_packet = (struct batadv_unicast_tvlv_packet *)tvlv_buff;
	unicast_tvlv_packet->packet_type = BATADV_UNICAST_TVLV;
	unicast_tvlv_packet->version = BATADV_COMPAT_VERSION;
	unicast_tvlv_packet->ttl = BATADV_TTL;
	unicast_tvlv_packet->reserved = 0;
	unicast_tvlv_packet->tvlv_len = htons(tvlv_len);
	unicast_tvlv_packet->align = 0;
	ether_addr_copy(unicast_tvlv_packet->src, src);
	ether_addr_copy(unicast_tvlv_packet->dst, dst);

	tvlv_buff = (unsigned char *)(unicast_tvlv_packet + 1);
	tvlv_hdr = (struct batadv_tvlv_hdr *)tvlv_buff;
	tvlv_hdr->version = version;
	tvlv_hdr->type = type;
	tvlv_hdr->len = htons(tvlv_value_len);
	tvlv_buff += sizeof(*tvlv_hdr);
	memcpy(tvlv_buff, tvlv_value, tvlv_value_len);

	if (batadv_send_skb_to_orig(skb, orig_node, NULL) != NET_XMIT_DROP)
		ret = true;

out:
	if (skb && !ret)
		kfree_skb(skb);
	if (orig_node)
		batadv_orig_node_free_ref(orig_node);
}

/**
 * batadv_get_vid - extract the VLAN identifier from skb if any
 * @skb: the buffer containing the packet
 * @header_len: length of the batman header preceding the ethernet header
 *
 * If the packet embedded in the skb is vlan tagged this function returns the
 * VID with the BATADV_VLAN_HAS_TAG flag. Otherwise BATADV_NO_FLAGS is returned.
 */
unsigned short batadv_get_vid(struct sk_buff *skb, size_t header_len)
{
	struct ethhdr *ethhdr = (struct ethhdr *)(skb->data + header_len);
	struct vlan_ethhdr *vhdr;
	unsigned short vid;

	if (ethhdr->h_proto != htons(ETH_P_8021Q))
		return BATADV_NO_FLAGS;

	if (!pskb_may_pull(skb, header_len + VLAN_ETH_HLEN))
		return BATADV_NO_FLAGS;

	vhdr = (struct vlan_ethhdr *)(skb->data + header_len);
	vid = ntohs(vhdr->h_vlan_TCI) & VLAN_VID_MASK;
	vid |= BATADV_VLAN_HAS_TAG;

	return vid;
}

/**
 * batadv_vlan_ap_isola_get - return the AP isolation status for the given vlan
 * @bat_priv: the bat priv with all the soft interface information
 * @vid: the VLAN identifier for which the AP isolation attributed as to be
 *  looked up
 *
 * Returns true if AP isolation is on for the VLAN idenfied by vid, false
 * otherwise
 */
bool batadv_vlan_ap_isola_get(struct batadv_priv *bat_priv, unsigned short vid)
{
	bool ap_isolation_enabled = false;
	struct batadv_softif_vlan *vlan;

	/* if the AP isolation is requested on a VLAN, then check for its
	 * setting in the proper VLAN private data structure
	 */
	vlan = batadv_softif_vlan_get(bat_priv, vid);
	if (vlan) {
		ap_isolation_enabled = atomic_read(&vlan->ap_isolation);
		batadv_softif_vlan_free_ref(vlan);
	}

	return ap_isolation_enabled;
}

static int batadv_param_set_ra(const char *val, const struct kernel_param *kp)
{
	struct batadv_algo_ops *bat_algo_ops;
	char *algo_name = (char *)val;
	size_t name_len = strlen(algo_name);

	if (name_len > 0 && algo_name[name_len - 1] == '\n')
		algo_name[name_len - 1] = '\0';

	bat_algo_ops = batadv_algo_get(algo_name);
	if (!bat_algo_ops) {
		pr_err("Routing algorithm '%s' is not supported\n", algo_name);
		return -EINVAL;
	}

	return param_set_copystring(algo_name, kp);
}

static const struct kernel_param_ops batadv_param_ops_ra = {
	.set = batadv_param_set_ra,
	.get = param_get_string,
};

static struct kparam_string batadv_param_string_ra = {
	.maxlen = sizeof(batadv_routing_algo),
	.string = batadv_routing_algo,
};

module_param_cb(routing_algo, &batadv_param_ops_ra, &batadv_param_string_ra,
		0644);
module_init(batadv_init);
module_exit(batadv_exit);

MODULE_LICENSE("GPL");

MODULE_AUTHOR(BATADV_DRIVER_AUTHOR);
MODULE_DESCRIPTION(BATADV_DRIVER_DESC);
MODULE_SUPPORTED_DEVICE(BATADV_DRIVER_DEVICE);
MODULE_VERSION(BATADV_SOURCE_VERSION);