summaryrefslogtreecommitdiffstats
path: root/net/batman-adv/bridge_loop_avoidance.c
blob: 6a4f728680ae5c347f74c7930bf5c0d672c5f6bc (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
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
/* Copyright (C) 2011-2013 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 "hash.h"
#include "hard-interface.h"
#include "originator.h"
#include "bridge_loop_avoidance.h"
#include "translation-table.h"
#include "send.h"

#include <linux/etherdevice.h>
#include <linux/crc16.h>
#include <linux/if_arp.h>
#include <net/arp.h>
#include <linux/if_vlan.h>

static const uint8_t batadv_announce_mac[4] = {0x43, 0x05, 0x43, 0x05};

static void batadv_bla_periodic_work(struct work_struct *work);
static void
batadv_bla_send_announce(struct batadv_priv *bat_priv,
			 struct batadv_bla_backbone_gw *backbone_gw);

/* return the index of the claim */
static inline uint32_t batadv_choose_claim(const void *data, uint32_t size)
{
	struct batadv_bla_claim *claim = (struct batadv_bla_claim *)data;
	uint32_t hash = 0;

	hash = batadv_hash_bytes(hash, &claim->addr, sizeof(claim->addr));
	hash = batadv_hash_bytes(hash, &claim->vid, sizeof(claim->vid));

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

	return hash % size;
}

/* return the index of the backbone gateway */
static inline uint32_t batadv_choose_backbone_gw(const void *data,
						 uint32_t size)
{
	const struct batadv_bla_claim *claim = (struct batadv_bla_claim *)data;
	uint32_t hash = 0;

	hash = batadv_hash_bytes(hash, &claim->addr, sizeof(claim->addr));
	hash = batadv_hash_bytes(hash, &claim->vid, sizeof(claim->vid));

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

	return hash % size;
}


/* compares address and vid of two backbone gws */
static int batadv_compare_backbone_gw(const struct hlist_node *node,
				      const void *data2)
{
	const void *data1 = container_of(node, struct batadv_bla_backbone_gw,
					 hash_entry);
	const struct batadv_bla_backbone_gw *gw1 = data1, *gw2 = data2;

	if (!batadv_compare_eth(gw1->orig, gw2->orig))
		return 0;

	if (gw1->vid != gw2->vid)
		return 0;

	return 1;
}

/* compares address and vid of two claims */
static int batadv_compare_claim(const struct hlist_node *node,
				const void *data2)
{
	const void *data1 = container_of(node, struct batadv_bla_claim,
					 hash_entry);
	const struct batadv_bla_claim *cl1 = data1, *cl2 = data2;

	if (!batadv_compare_eth(cl1->addr, cl2->addr))
		return 0;

	if (cl1->vid != cl2->vid)
		return 0;

	return 1;
}

/* free a backbone gw */
static void
batadv_backbone_gw_free_ref(struct batadv_bla_backbone_gw *backbone_gw)
{
	if (atomic_dec_and_test(&backbone_gw->refcount))
		kfree_rcu(backbone_gw, rcu);
}

/* finally deinitialize the claim */
static void batadv_claim_free_rcu(struct rcu_head *rcu)
{
	struct batadv_bla_claim *claim;

	claim = container_of(rcu, struct batadv_bla_claim, rcu);

	batadv_backbone_gw_free_ref(claim->backbone_gw);
	kfree(claim);
}

/* free a claim, call claim_free_rcu if its the last reference */
static void batadv_claim_free_ref(struct batadv_bla_claim *claim)
{
	if (atomic_dec_and_test(&claim->refcount))
		call_rcu(&claim->rcu, batadv_claim_free_rcu);
}

/* @bat_priv: the bat priv with all the soft interface information
 * @data: search data (may be local/static data)
 *
 * looks for a claim in the hash, and returns it if found
 * or NULL otherwise.
 */
static struct batadv_bla_claim
*batadv_claim_hash_find(struct batadv_priv *bat_priv,
			struct batadv_bla_claim *data)
{
	struct batadv_hashtable *hash = bat_priv->bla.claim_hash;
	struct hlist_head *head;
	struct batadv_bla_claim *claim;
	struct batadv_bla_claim *claim_tmp = NULL;
	int index;

	if (!hash)
		return NULL;

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

	rcu_read_lock();
	hlist_for_each_entry_rcu(claim, head, hash_entry) {
		if (!batadv_compare_claim(&claim->hash_entry, data))
			continue;

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

		claim_tmp = claim;
		break;
	}
	rcu_read_unlock();

	return claim_tmp;
}

/**
 * batadv_backbone_hash_find - looks for a claim in the hash
 * @bat_priv: the bat priv with all the soft interface information
 * @addr: the address of the originator
 * @vid: the VLAN ID
 *
 * Returns claim if found or NULL otherwise.
 */
static struct batadv_bla_backbone_gw *
batadv_backbone_hash_find(struct batadv_priv *bat_priv,
			  uint8_t *addr, short vid)
{
	struct batadv_hashtable *hash = bat_priv->bla.backbone_hash;
	struct hlist_head *head;
	struct batadv_bla_backbone_gw search_entry, *backbone_gw;
	struct batadv_bla_backbone_gw *backbone_gw_tmp = NULL;
	int index;

	if (!hash)
		return NULL;

	memcpy(search_entry.orig, addr, ETH_ALEN);
	search_entry.vid = vid;

	index = batadv_choose_backbone_gw(&search_entry, hash->size);
	head = &hash->table[index];

	rcu_read_lock();
	hlist_for_each_entry_rcu(backbone_gw, head, hash_entry) {
		if (!batadv_compare_backbone_gw(&backbone_gw->hash_entry,
						&search_entry))
			continue;

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

		backbone_gw_tmp = backbone_gw;
		break;
	}
	rcu_read_unlock();

	return backbone_gw_tmp;
}

/* delete all claims for a backbone */
static void
batadv_bla_del_backbone_claims(struct batadv_bla_backbone_gw *backbone_gw)
{
	struct batadv_hashtable *hash;
	struct hlist_node *node_tmp;
	struct hlist_head *head;
	struct batadv_bla_claim *claim;
	int i;
	spinlock_t *list_lock;	/* protects write access to the hash lists */

	hash = backbone_gw->bat_priv->bla.claim_hash;
	if (!hash)
		return;

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

		spin_lock_bh(list_lock);
		hlist_for_each_entry_safe(claim, node_tmp,
					  head, hash_entry) {
			if (claim->backbone_gw != backbone_gw)
				continue;

			batadv_claim_free_ref(claim);
			hlist_del_rcu(&claim->hash_entry);
		}
		spin_unlock_bh(list_lock);
	}

	/* all claims gone, intialize CRC */
	backbone_gw->crc = BATADV_BLA_CRC_INIT;
}

/**
 * batadv_bla_send_claim - sends a claim frame according to the provided info
 * @bat_priv: the bat priv with all the soft interface information
 * @orig: the mac address to be announced within the claim
 * @vid: the VLAN ID
 * @claimtype: the type of the claim (CLAIM, UNCLAIM, ANNOUNCE, ...)
 */
static void batadv_bla_send_claim(struct batadv_priv *bat_priv, uint8_t *mac,
				  short vid, int claimtype)
{
	struct sk_buff *skb;
	struct ethhdr *ethhdr;
	struct batadv_hard_iface *primary_if;
	struct net_device *soft_iface;
	uint8_t *hw_src;
	struct batadv_bla_claim_dst local_claim_dest;
	__be32 zeroip = 0;

	primary_if = batadv_primary_if_get_selected(bat_priv);
	if (!primary_if)
		return;

	memcpy(&local_claim_dest, &bat_priv->bla.claim_dest,
	       sizeof(local_claim_dest));
	local_claim_dest.type = claimtype;

	soft_iface = primary_if->soft_iface;

	skb = arp_create(ARPOP_REPLY, ETH_P_ARP,
			 /* IP DST: 0.0.0.0 */
			 zeroip,
			 primary_if->soft_iface,
			 /* IP SRC: 0.0.0.0 */
			 zeroip,
			 /* Ethernet DST: Broadcast */
			 NULL,
			 /* Ethernet SRC/HW SRC:  originator mac */
			 primary_if->net_dev->dev_addr,
			 /* HW DST: FF:43:05:XX:YY:YY
			  * with XX   = claim type
			  * and YY:YY = group id
			  */
			 (uint8_t *)&local_claim_dest);

	if (!skb)
		goto out;

	ethhdr = (struct ethhdr *)skb->data;
	hw_src = (uint8_t *)ethhdr + ETH_HLEN + sizeof(struct arphdr);

	/* now we pretend that the client would have sent this ... */
	switch (claimtype) {
	case BATADV_CLAIM_TYPE_CLAIM:
		/* normal claim frame
		 * set Ethernet SRC to the clients mac
		 */
		memcpy(ethhdr->h_source, mac, ETH_ALEN);
		batadv_dbg(BATADV_DBG_BLA, bat_priv,
			   "bla_send_claim(): CLAIM %pM on vid %d\n", mac, vid);
		break;
	case BATADV_CLAIM_TYPE_UNCLAIM:
		/* unclaim frame
		 * set HW SRC to the clients mac
		 */
		memcpy(hw_src, mac, ETH_ALEN);
		batadv_dbg(BATADV_DBG_BLA, bat_priv,
			   "bla_send_claim(): UNCLAIM %pM on vid %d\n", mac,
			   vid);
		break;
	case BATADV_CLAIM_TYPE_ANNOUNCE:
		/* announcement frame
		 * set HW SRC to the special mac containg the crc
		 */
		memcpy(hw_src, mac, ETH_ALEN);
		batadv_dbg(BATADV_DBG_BLA, bat_priv,
			   "bla_send_claim(): ANNOUNCE of %pM on vid %d\n",
			   ethhdr->h_source, vid);
		break;
	case BATADV_CLAIM_TYPE_REQUEST:
		/* request frame
		 * set HW SRC and header destination to the receiving backbone
		 * gws mac
		 */
		memcpy(hw_src, mac, ETH_ALEN);
		memcpy(ethhdr->h_dest, mac, ETH_ALEN);
		batadv_dbg(BATADV_DBG_BLA, bat_priv,
			   "bla_send_claim(): REQUEST of %pM to %pMon vid %d\n",
			   ethhdr->h_source, ethhdr->h_dest, vid);
		break;
	}

	if (vid != -1)
		skb = vlan_insert_tag(skb, vid);

	skb_reset_mac_header(skb);
	skb->protocol = eth_type_trans(skb, soft_iface);
	batadv_inc_counter(bat_priv, BATADV_CNT_RX);
	batadv_add_counter(bat_priv, BATADV_CNT_RX_BYTES,
			   skb->len + ETH_HLEN);
	soft_iface->last_rx = jiffies;

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

/**
 * batadv_bla_get_backbone_gw
 * @bat_priv: the bat priv with all the soft interface information
 * @orig: the mac address of the originator
 * @vid: the VLAN ID
 *
 * searches for the backbone gw or creates a new one if it could not
 * be found.
 */
static struct batadv_bla_backbone_gw *
batadv_bla_get_backbone_gw(struct batadv_priv *bat_priv, uint8_t *orig,
			   short vid, bool own_backbone)
{
	struct batadv_bla_backbone_gw *entry;
	struct batadv_orig_node *orig_node;
	int hash_added;

	entry = batadv_backbone_hash_find(bat_priv, orig, vid);

	if (entry)
		return entry;

	batadv_dbg(BATADV_DBG_BLA, bat_priv,
		   "bla_get_backbone_gw(): not found (%pM, %d), creating new entry\n",
		   orig, vid);

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

	entry->vid = vid;
	entry->lasttime = jiffies;
	entry->crc = BATADV_BLA_CRC_INIT;
	entry->bat_priv = bat_priv;
	atomic_set(&entry->request_sent, 0);
	atomic_set(&entry->wait_periods, 0);
	memcpy(entry->orig, orig, ETH_ALEN);

	/* one for the hash, one for returning */
	atomic_set(&entry->refcount, 2);

	hash_added = batadv_hash_add(bat_priv->bla.backbone_hash,
				     batadv_compare_backbone_gw,
				     batadv_choose_backbone_gw, entry,
				     &entry->hash_entry);

	if (unlikely(hash_added != 0)) {
		/* hash failed, free the structure */
		kfree(entry);
		return NULL;
	}

	/* this is a gateway now, remove any tt entries */
	orig_node = batadv_orig_hash_find(bat_priv, orig);
	if (orig_node) {
		batadv_tt_global_del_orig(bat_priv, orig_node,
					  "became a backbone gateway");
		batadv_orig_node_free_ref(orig_node);
	}

	if (own_backbone) {
		batadv_bla_send_announce(bat_priv, entry);

		/* this will be decreased in the worker thread */
		atomic_inc(&entry->request_sent);
		atomic_set(&entry->wait_periods, BATADV_BLA_WAIT_PERIODS);
		atomic_inc(&bat_priv->bla.num_requests);
	}

	return entry;
}

/* update or add the own backbone gw to make sure we announce
 * where we receive other backbone gws
 */
static void
batadv_bla_update_own_backbone_gw(struct batadv_priv *bat_priv,
				  struct batadv_hard_iface *primary_if,
				  short vid)
{
	struct batadv_bla_backbone_gw *backbone_gw;

	backbone_gw = batadv_bla_get_backbone_gw(bat_priv,
						 primary_if->net_dev->dev_addr,
						 vid, true);
	if (unlikely(!backbone_gw))
		return;

	backbone_gw->lasttime = jiffies;
	batadv_backbone_gw_free_ref(backbone_gw);
}

/* @bat_priv: the bat priv with all the soft interface information
 * @vid: the vid where the request came on
 *
 * Repeat all of our own claims, and finally send an ANNOUNCE frame
 * to allow the requester another check if the CRC is correct now.
 */
static void batadv_bla_answer_request(struct batadv_priv *bat_priv,
				      struct batadv_hard_iface *primary_if,
				      short vid)
{
	struct hlist_head *head;
	struct batadv_hashtable *hash;
	struct batadv_bla_claim *claim;
	struct batadv_bla_backbone_gw *backbone_gw;
	int i;

	batadv_dbg(BATADV_DBG_BLA, bat_priv,
		   "bla_answer_request(): received a claim request, send all of our own claims again\n");

	backbone_gw = batadv_backbone_hash_find(bat_priv,
						primary_if->net_dev->dev_addr,
						vid);
	if (!backbone_gw)
		return;

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

		rcu_read_lock();
		hlist_for_each_entry_rcu(claim, head, hash_entry) {
			/* only own claims are interesting */
			if (claim->backbone_gw != backbone_gw)
				continue;

			batadv_bla_send_claim(bat_priv, claim->addr, claim->vid,
					      BATADV_CLAIM_TYPE_CLAIM);
		}
		rcu_read_unlock();
	}

	/* finally, send an announcement frame */
	batadv_bla_send_announce(bat_priv, backbone_gw);
	batadv_backbone_gw_free_ref(backbone_gw);
}

/* @backbone_gw: the backbone gateway from whom we are out of sync
 *
 * When the crc is wrong, ask the backbone gateway for a full table update.
 * After the request, it will repeat all of his own claims and finally
 * send an announcement claim with which we can check again.
 */
static void batadv_bla_send_request(struct batadv_bla_backbone_gw *backbone_gw)
{
	/* first, remove all old entries */
	batadv_bla_del_backbone_claims(backbone_gw);

	batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv,
		   "Sending REQUEST to %pM\n", backbone_gw->orig);

	/* send request */
	batadv_bla_send_claim(backbone_gw->bat_priv, backbone_gw->orig,
			      backbone_gw->vid, BATADV_CLAIM_TYPE_REQUEST);

	/* no local broadcasts should be sent or received, for now. */
	if (!atomic_read(&backbone_gw->request_sent)) {
		atomic_inc(&backbone_gw->bat_priv->bla.num_requests);
		atomic_set(&backbone_gw->request_sent, 1);
	}
}

/* @bat_priv: the bat priv with all the soft interface information
 * @backbone_gw: our backbone gateway which should be announced
 *
 * This function sends an announcement. It is called from multiple
 * places.
 */
static void batadv_bla_send_announce(struct batadv_priv *bat_priv,
				     struct batadv_bla_backbone_gw *backbone_gw)
{
	uint8_t mac[ETH_ALEN];
	__be16 crc;

	memcpy(mac, batadv_announce_mac, 4);
	crc = htons(backbone_gw->crc);
	memcpy(&mac[4], &crc, 2);

	batadv_bla_send_claim(bat_priv, mac, backbone_gw->vid,
			      BATADV_CLAIM_TYPE_ANNOUNCE);
}

/**
 * batadv_bla_add_claim - Adds a claim in the claim hash
 * @bat_priv: the bat priv with all the soft interface information
 * @mac: the mac address of the claim
 * @vid: the VLAN ID of the frame
 * @backbone_gw: the backbone gateway which claims it
 */
static void batadv_bla_add_claim(struct batadv_priv *bat_priv,
				 const uint8_t *mac, const short vid,
				 struct batadv_bla_backbone_gw *backbone_gw)
{
	struct batadv_bla_claim *claim;
	struct batadv_bla_claim search_claim;
	int hash_added;

	memcpy(search_claim.addr, mac, ETH_ALEN);
	search_claim.vid = vid;
	claim = batadv_claim_hash_find(bat_priv, &search_claim);

	/* create a new claim entry if it does not exist yet. */
	if (!claim) {
		claim = kzalloc(sizeof(*claim), GFP_ATOMIC);
		if (!claim)
			return;

		memcpy(claim->addr, mac, ETH_ALEN);
		claim->vid = vid;
		claim->lasttime = jiffies;
		claim->backbone_gw = backbone_gw;

		atomic_set(&claim->refcount, 2);
		batadv_dbg(BATADV_DBG_BLA, bat_priv,
			   "bla_add_claim(): adding new entry %pM, vid %d to hash ...\n",
			   mac, vid);
		hash_added = batadv_hash_add(bat_priv->bla.claim_hash,
					     batadv_compare_claim,
					     batadv_choose_claim, claim,
					     &claim->hash_entry);

		if (unlikely(hash_added != 0)) {
			/* only local changes happened. */
			kfree(claim);
			return;
		}
	} else {
		claim->lasttime = jiffies;
		if (claim->backbone_gw == backbone_gw)
			/* no need to register a new backbone */
			goto claim_free_ref;

		batadv_dbg(BATADV_DBG_BLA, bat_priv,
			   "bla_add_claim(): changing ownership for %pM, vid %d\n",
			   mac, vid);

		claim->backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
		batadv_backbone_gw_free_ref(claim->backbone_gw);
	}
	/* set (new) backbone gw */
	atomic_inc(&backbone_gw->refcount);
	claim->backbone_gw = backbone_gw;

	backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);
	backbone_gw->lasttime = jiffies;

claim_free_ref:
	batadv_claim_free_ref(claim);
}

/* Delete a claim from the claim hash which has the
 * given mac address and vid.
 */
static void batadv_bla_del_claim(struct batadv_priv *bat_priv,
				 const uint8_t *mac, const short vid)
{
	struct batadv_bla_claim search_claim, *claim;

	memcpy(search_claim.addr, mac, ETH_ALEN);
	search_claim.vid = vid;
	claim = batadv_claim_hash_find(bat_priv, &search_claim);
	if (!claim)
		return;

	batadv_dbg(BATADV_DBG_BLA, bat_priv, "bla_del_claim(): %pM, vid %d\n",
		   mac, vid);

	batadv_hash_remove(bat_priv->bla.claim_hash, batadv_compare_claim,
			   batadv_choose_claim, claim);
	batadv_claim_free_ref(claim); /* reference from the hash is gone */

	claim->backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN);

	/* don't need the reference from hash_find() anymore */
	batadv_claim_free_ref(claim);
}

/* check for ANNOUNCE frame, return 1 if handled */
static int batadv_handle_announce(struct batadv_priv *bat_priv,
				  uint8_t *an_addr, uint8_t *backbone_addr,
				  short vid)
{
	struct batadv_bla_backbone_gw *backbone_gw;
	uint16_t crc;

	if (memcmp(an_addr, batadv_announce_mac, 4) != 0)
		return 0;

	backbone_gw = batadv_bla_get_backbone_gw(bat_priv, backbone_addr, vid,
						 false);

	if (unlikely(!backbone_gw))
		return 1;


	/* handle as ANNOUNCE frame */
	backbone_gw->lasttime = jiffies;
	crc = ntohs(*((__be16 *)(&an_addr[4])));

	batadv_dbg(BATADV_DBG_BLA, bat_priv,
		   "handle_announce(): ANNOUNCE vid %d (sent by %pM)... CRC = %#.4x\n",
		   vid, backbone_gw->orig, crc);

	if (backbone_gw->crc != crc) {
		batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv,
			   "handle_announce(): CRC FAILED for %pM/%d (my = %#.4x, sent = %#.4x)\n",
			   backbone_gw->orig, backbone_gw->vid,
			   backbone_gw->crc, crc);

		batadv_bla_send_request(backbone_gw);
	} else {
		/* if we have sent a request and the crc was OK,
		 * we can allow traffic again.
		 */
		if (atomic_read(&backbone_gw->request_sent)) {
			atomic_dec(&backbone_gw->bat_priv->bla.num_requests);
			atomic_set(&backbone_gw->request_sent, 0);
		}
	}

	batadv_backbone_gw_free_ref(backbone_gw);
	return 1;
}

/* check for REQUEST frame, return 1 if handled */
static int batadv_handle_request(struct batadv_priv *bat_priv,
				 struct batadv_hard_iface *primary_if,
				 uint8_t *backbone_addr,
				 struct ethhdr *ethhdr, short vid)
{
	/* check for REQUEST frame */
	if (!batadv_compare_eth(backbone_addr, ethhdr->h_dest))
		return 0;

	/* sanity check, this should not happen on a normal switch,
	 * we ignore it in this case.
	 */
	if (!batadv_compare_eth(ethhdr->h_dest, primary_if->net_dev->dev_addr))
		return 1;

	batadv_dbg(BATADV_DBG_BLA, bat_priv,
		   "handle_request(): REQUEST vid %d (sent by %pM)...\n",
		   vid, ethhdr->h_source);

	batadv_bla_answer_request(bat_priv, primary_if, vid);
	return 1;
}

/* check for UNCLAIM frame, return 1 if handled */
static int batadv_handle_unclaim(struct batadv_priv *bat_priv,
				 struct batadv_hard_iface *primary_if,
				 uint8_t *backbone_addr,
				 uint8_t *claim_addr, short vid)
{
	struct batadv_bla_backbone_gw *backbone_gw;

	/* unclaim in any case if it is our own */
	if (primary_if && batadv_compare_eth(backbone_addr,
					     primary_if->net_dev->dev_addr))
		batadv_bla_send_claim(bat_priv, claim_addr, vid,
				      BATADV_CLAIM_TYPE_UNCLAIM);

	backbone_gw = batadv_backbone_hash_find(bat_priv, backbone_addr, vid);

	if (!backbone_gw)
		return 1;

	/* this must be an UNCLAIM frame */
	batadv_dbg(BATADV_DBG_BLA, bat_priv,
		   "handle_unclaim(): UNCLAIM %pM on vid %d (sent by %pM)...\n",
		   claim_addr, vid, backbone_gw->orig);

	batadv_bla_del_claim(bat_priv, claim_addr, vid);
	batadv_backbone_gw_free_ref(backbone_gw);
	return 1;
}

/* check for CLAIM frame, return 1 if handled */
static int batadv_handle_claim(struct batadv_priv *bat_priv,
			       struct batadv_hard_iface *primary_if,
			       uint8_t *backbone_addr, uint8_t *claim_addr,
			       short vid)
{
	struct batadv_bla_backbone_gw *backbone_gw;

	/* register the gateway if not yet available, and add the claim. */

	backbone_gw = batadv_bla_get_backbone_gw(bat_priv, backbone_addr, vid,
						 false);

	if (unlikely(!backbone_gw))
		return 1;

	/* this must be a CLAIM frame */
	batadv_bla_add_claim(bat_priv, claim_addr, vid, backbone_gw);
	if (batadv_compare_eth(backbone_addr, primary_if->net_dev->dev_addr))
		batadv_bla_send_claim(bat_priv, claim_addr, vid,
				      BATADV_CLAIM_TYPE_CLAIM);

	/* TODO: we could call something like tt_local_del() here. */

	batadv_backbone_gw_free_ref(backbone_gw);
	return 1;
}

/**
 * batadv_check_claim_group
 * @bat_priv: the bat priv with all the soft interface information
 * @hw_src: the Hardware source in the ARP Header
 * @hw_dst: the Hardware destination in the ARP Header
 * @ethhdr: pointer to the Ethernet header of the claim frame
 *
 * checks if it is a claim packet and if its on the same group.
 * This function also applies the group ID of the sender
 * if it is in the same mesh.
 *
 * returns:
 *	2  - if it is a claim packet and on the same group
 *	1  - if is a claim packet from another group
 *	0  - if it is not a claim packet
 */
static int batadv_check_claim_group(struct batadv_priv *bat_priv,
				    struct batadv_hard_iface *primary_if,
				    uint8_t *hw_src, uint8_t *hw_dst,
				    struct ethhdr *ethhdr)
{
	uint8_t *backbone_addr;
	struct batadv_orig_node *orig_node;
	struct batadv_bla_claim_dst *bla_dst, *bla_dst_own;

	bla_dst = (struct batadv_bla_claim_dst *)hw_dst;
	bla_dst_own = &bat_priv->bla.claim_dest;

	/* check if it is a claim packet in general */
	if (memcmp(bla_dst->magic, bla_dst_own->magic,
		   sizeof(bla_dst->magic)) != 0)
		return 0;

	/* if announcement packet, use the source,
	 * otherwise assume it is in the hw_src
	 */
	switch (bla_dst->type) {
	case BATADV_CLAIM_TYPE_CLAIM:
		backbone_addr = hw_src;
		break;
	case BATADV_CLAIM_TYPE_REQUEST:
	case BATADV_CLAIM_TYPE_ANNOUNCE:
	case BATADV_CLAIM_TYPE_UNCLAIM:
		backbone_addr = ethhdr->h_source;
		break;
	default:
		return 0;
	}

	/* don't accept claim frames from ourselves */
	if (batadv_compare_eth(backbone_addr, primary_if->net_dev->dev_addr))
		return 0;

	/* if its already the same group, it is fine. */
	if (bla_dst->group == bla_dst_own->group)
		return 2;

	/* lets see if this originator is in our mesh */
	orig_node = batadv_orig_hash_find(bat_priv, backbone_addr);

	/* dont accept claims from gateways which are not in
	 * the same mesh or group.
	 */
	if (!orig_node)
		return 1;

	/* if our mesh friends mac is bigger, use it for ourselves. */
	if (ntohs(bla_dst->group) > ntohs(bla_dst_own->group)) {
		batadv_dbg(BATADV_DBG_BLA, bat_priv,
			   "taking other backbones claim group: %#.4x\n",
			   ntohs(bla_dst->group));
		bla_dst_own->group = bla_dst->group;
	}

	batadv_orig_node_free_ref(orig_node);

	return 2;
}


/* @bat_priv: the bat priv with all the soft interface information
 * @skb: the frame to be checked
 *
 * Check if this is a claim frame, and process it accordingly.
 *
 * returns 1 if it was a claim frame, otherwise return 0 to
 * tell the callee that it can use the frame on its own.
 */
static int batadv_bla_process_claim(struct batadv_priv *bat_priv,
				    struct batadv_hard_iface *primary_if,
				    struct sk_buff *skb)
{
	struct ethhdr *ethhdr;
	struct vlan_ethhdr *vhdr;
	struct arphdr *arphdr;
	uint8_t *hw_src, *hw_dst;
	struct batadv_bla_claim_dst *bla_dst;
	uint16_t proto;
	int headlen;
	short vid = -1;
	int ret;

	ethhdr = (struct ethhdr *)skb_mac_header(skb);

	if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) {
		vhdr = (struct vlan_ethhdr *)ethhdr;
		vid = ntohs(vhdr->h_vlan_TCI) & VLAN_VID_MASK;
		proto = ntohs(vhdr->h_vlan_encapsulated_proto);
		headlen = sizeof(*vhdr);
	} else {
		proto = ntohs(ethhdr->h_proto);
		headlen = ETH_HLEN;
	}

	if (proto != ETH_P_ARP)
		return 0; /* not a claim frame */

	/* this must be a ARP frame. check if it is a claim. */

	if (unlikely(!pskb_may_pull(skb, headlen + arp_hdr_len(skb->dev))))
		return 0;

	/* pskb_may_pull() may have modified the pointers, get ethhdr again */
	ethhdr = (struct ethhdr *)skb_mac_header(skb);
	arphdr = (struct arphdr *)((uint8_t *)ethhdr + headlen);

	/* Check whether the ARP frame carries a valid
	 * IP information
	 */
	if (arphdr->ar_hrd != htons(ARPHRD_ETHER))
		return 0;
	if (arphdr->ar_pro != htons(ETH_P_IP))
		return 0;
	if (arphdr->ar_hln != ETH_ALEN)
		return 0;
	if (arphdr->ar_pln != 4)
		return 0;

	hw_src = (uint8_t *)arphdr + sizeof(struct arphdr);
	hw_dst = hw_src + ETH_ALEN + 4;
	bla_dst = (struct batadv_bla_claim_dst *)hw_dst;

	/* check if it is a claim frame. */
	ret = batadv_check_claim_group(bat_priv, primary_if, hw_src, hw_dst,
				       ethhdr);
	if (ret == 1)
		batadv_dbg(BATADV_DBG_BLA, bat_priv,
			   "bla_process_claim(): received a claim frame from another group. From: %pM on vid %d ...(hw_src %pM, hw_dst %pM)\n",
			   ethhdr->h_source, vid, hw_src, hw_dst);

	if (ret < 2)
		return ret;

	/* become a backbone gw ourselves on this vlan if not happened yet */
	batadv_bla_update_own_backbone_gw(bat_priv, primary_if, vid);

	/* check for the different types of claim frames ... */
	switch (bla_dst->type) {
	case BATADV_CLAIM_TYPE_CLAIM:
		if (batadv_handle_claim(bat_priv, primary_if, hw_src,
					ethhdr->h_source, vid))
			return 1;
		break;
	case BATADV_CLAIM_TYPE_UNCLAIM:
		if (batadv_handle_unclaim(bat_priv, primary_if,
					  ethhdr->h_source, hw_src, vid))
			return 1;
		break;

	case BATADV_CLAIM_TYPE_ANNOUNCE:
		if (batadv_handle_announce(bat_priv, hw_src, ethhdr->h_source,
					   vid))
			return 1;
		break;
	case BATADV_CLAIM_TYPE_REQUEST:
		if (batadv_handle_request(bat_priv, primary_if, hw_src, ethhdr,
					  vid))
			return 1;
		break;
	}

	batadv_dbg(BATADV_DBG_BLA, bat_priv,
		   "bla_process_claim(): ERROR - this looks like a claim frame, but is useless. eth src %pM on vid %d ...(hw_src %pM, hw_dst %pM)\n",
		   ethhdr->h_source, vid, hw_src, hw_dst);
	return 1;
}

/* Check when we last heard from other nodes, and remove them in case of
 * a time out, or clean all backbone gws if now is set.
 */
static void batadv_bla_purge_backbone_gw(struct batadv_priv *bat_priv, int now)
{
	struct batadv_bla_backbone_gw *backbone_gw;
	struct hlist_node *node_tmp;
	struct hlist_head *head;
	struct batadv_hashtable *hash;
	spinlock_t *list_lock;	/* protects write access to the hash lists */
	int i;

	hash = bat_priv->bla.backbone_hash;
	if (!hash)
		return;

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

		spin_lock_bh(list_lock);
		hlist_for_each_entry_safe(backbone_gw, node_tmp,
					  head, hash_entry) {
			if (now)
				goto purge_now;
			if (!batadv_has_timed_out(backbone_gw->lasttime,
						  BATADV_BLA_BACKBONE_TIMEOUT))
				continue;

			batadv_dbg(BATADV_DBG_BLA, backbone_gw->bat_priv,
				   "bla_purge_backbone_gw(): backbone gw %pM timed out\n",
				   backbone_gw->orig);

purge_now:
			/* don't wait for the pending request anymore */
			if (atomic_read(&backbone_gw->request_sent))
				atomic_dec(&bat_priv->bla.num_requests);

			batadv_bla_del_backbone_claims(backbone_gw);

			hlist_del_rcu(&backbone_gw->hash_entry);
			batadv_backbone_gw_free_ref(backbone_gw);
		}
		spin_unlock_bh(list_lock);
	}
}

/**
 * batadv_bla_purge_claims
 * @bat_priv: the bat priv with all the soft interface information
 * @primary_if: the selected primary interface, may be NULL if now is set
 * @now: whether the whole hash shall be wiped now
 *
 * Check when we heard last time from our own claims, and remove them in case of
 * a time out, or clean all claims if now is set
 */
static void batadv_bla_purge_claims(struct batadv_priv *bat_priv,
				    struct batadv_hard_iface *primary_if,
				    int now)
{
	struct batadv_bla_claim *claim;
	struct hlist_head *head;
	struct batadv_hashtable *hash;
	int i;

	hash = bat_priv->bla.claim_hash;
	if (!hash)
		return;

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

		rcu_read_lock();
		hlist_for_each_entry_rcu(claim, head, hash_entry) {
			if (now)
				goto purge_now;
			if (!batadv_compare_eth(claim->backbone_gw->orig,
						primary_if->net_dev->dev_addr))
				continue;
			if (!batadv_has_timed_out(claim->lasttime,
						  BATADV_BLA_CLAIM_TIMEOUT))
				continue;

			batadv_dbg(BATADV_DBG_BLA, bat_priv,
				   "bla_purge_claims(): %pM, vid %d, time out\n",
				   claim->addr, claim->vid);

purge_now:
			batadv_handle_unclaim(bat_priv, primary_if,
					      claim->backbone_gw->orig,
					      claim->addr, claim->vid);
		}
		rcu_read_unlock();
	}
}

/**
 * batadv_bla_update_orig_address
 * @bat_priv: the bat priv with all the soft interface information
 * @primary_if: the new selected primary_if
 * @oldif: the old primary interface, may be NULL
 *
 * Update the backbone gateways when the own orig address changes.
 */
void batadv_bla_update_orig_address(struct batadv_priv *bat_priv,
				    struct batadv_hard_iface *primary_if,
				    struct batadv_hard_iface *oldif)
{
	struct batadv_bla_backbone_gw *backbone_gw;
	struct hlist_head *head;
	struct batadv_hashtable *hash;
	__be16 group;
	int i;

	/* reset bridge loop avoidance group id */
	group = htons(crc16(0, primary_if->net_dev->dev_addr, ETH_ALEN));
	bat_priv->bla.claim_dest.group = group;

	if (!oldif) {
		batadv_bla_purge_claims(bat_priv, NULL, 1);
		batadv_bla_purge_backbone_gw(bat_priv, 1);
		return;
	}

	hash = bat_priv->bla.backbone_hash;
	if (!hash)
		return;

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

		rcu_read_lock();
		hlist_for_each_entry_rcu(backbone_gw, head, hash_entry) {
			/* own orig still holds the old value. */
			if (!batadv_compare_eth(backbone_gw->orig,
						oldif->net_dev->dev_addr))
				continue;

			memcpy(backbone_gw->orig,
			       primary_if->net_dev->dev_addr, ETH_ALEN);
			/* send an announce frame so others will ask for our
			 * claims and update their tables.
			 */
			batadv_bla_send_announce(bat_priv, backbone_gw);
		}
		rcu_read_unlock();
	}
}

/* periodic work to do:
 *  * purge structures when they are too old
 *  * send announcements
 */
static void batadv_bla_periodic_work(struct work_struct *work)
{
	struct delayed_work *delayed_work;
	struct batadv_priv *bat_priv;
	struct batadv_priv_bla *priv_bla;
	struct hlist_head *head;
	struct batadv_bla_backbone_gw *backbone_gw;
	struct batadv_hashtable *hash;
	struct batadv_hard_iface *primary_if;
	int i;

	delayed_work = container_of(work, struct delayed_work, work);
	priv_bla = container_of(delayed_work, struct batadv_priv_bla, work);
	bat_priv = container_of(priv_bla, struct batadv_priv, bla);
	primary_if = batadv_primary_if_get_selected(bat_priv);
	if (!primary_if)
		goto out;

	batadv_bla_purge_claims(bat_priv, primary_if, 0);
	batadv_bla_purge_backbone_gw(bat_priv, 0);

	if (!atomic_read(&bat_priv->bridge_loop_avoidance))
		goto out;

	hash = bat_priv->bla.backbone_hash;
	if (!hash)
		goto out;

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

		rcu_read_lock();
		hlist_for_each_entry_rcu(backbone_gw, head, hash_entry) {
			if (!batadv_compare_eth(backbone_gw->orig,
						primary_if->net_dev->dev_addr))
				continue;

			backbone_gw->lasttime = jiffies;

			batadv_bla_send_announce(bat_priv, backbone_gw);

			/* request_sent is only set after creation to avoid
			 * problems when we are not yet known as backbone gw
			 * in the backbone.
			 *
			 * We can reset this now after we waited some periods
			 * to give bridge forward delays and bla group forming
			 * some grace time.
			 */

			if (atomic_read(&backbone_gw->request_sent) == 0)
				continue;

			if (!atomic_dec_and_test(&backbone_gw->wait_periods))
				continue;

			atomic_dec(&backbone_gw->bat_priv->bla.num_requests);
			atomic_set(&backbone_gw->request_sent, 0);
		}
		rcu_read_unlock();
	}
out:
	if (primary_if)
		batadv_hardif_free_ref(primary_if);

	queue_delayed_work(batadv_event_workqueue, &bat_priv->bla.work,
			   msecs_to_jiffies(BATADV_BLA_PERIOD_LENGTH));
}

/* The hash for claim and backbone hash receive the same key because they
 * are getting initialized by hash_new with the same key. Reinitializing
 * them with to different keys to allow nested locking without generating
 * lockdep warnings
 */
static struct lock_class_key batadv_claim_hash_lock_class_key;
static struct lock_class_key batadv_backbone_hash_lock_class_key;

/* initialize all bla structures */
int batadv_bla_init(struct batadv_priv *bat_priv)
{
	int i;
	uint8_t claim_dest[ETH_ALEN] = {0xff, 0x43, 0x05, 0x00, 0x00, 0x00};
	struct batadv_hard_iface *primary_if;
	uint16_t crc;
	unsigned long entrytime;

	spin_lock_init(&bat_priv->bla.bcast_duplist_lock);

	batadv_dbg(BATADV_DBG_BLA, bat_priv, "bla hash registering\n");

	/* setting claim destination address */
	memcpy(&bat_priv->bla.claim_dest.magic, claim_dest, 3);
	bat_priv->bla.claim_dest.type = 0;
	primary_if = batadv_primary_if_get_selected(bat_priv);
	if (primary_if) {
		crc = crc16(0, primary_if->net_dev->dev_addr, ETH_ALEN);
		bat_priv->bla.claim_dest.group = htons(crc);
		batadv_hardif_free_ref(primary_if);
	} else {
		bat_priv->bla.claim_dest.group = 0; /* will be set later */
	}

	/* initialize the duplicate list */
	entrytime = jiffies - msecs_to_jiffies(BATADV_DUPLIST_TIMEOUT);
	for (i = 0; i < BATADV_DUPLIST_SIZE; i++)
		bat_priv->bla.bcast_duplist[i].entrytime = entrytime;
	bat_priv->bla.bcast_duplist_curr = 0;

	if (bat_priv->bla.claim_hash)
		return 0;

	bat_priv->bla.claim_hash = batadv_hash_new(128);
	bat_priv->bla.backbone_hash = batadv_hash_new(32);

	if (!bat_priv->bla.claim_hash || !bat_priv->bla.backbone_hash)
		return -ENOMEM;

	batadv_hash_set_lock_class(bat_priv->bla.claim_hash,
				   &batadv_claim_hash_lock_class_key);
	batadv_hash_set_lock_class(bat_priv->bla.backbone_hash,
				   &batadv_backbone_hash_lock_class_key);

	batadv_dbg(BATADV_DBG_BLA, bat_priv, "bla hashes initialized\n");

	INIT_DELAYED_WORK(&bat_priv->bla.work, batadv_bla_periodic_work);

	queue_delayed_work(batadv_event_workqueue, &bat_priv->bla.work,
			   msecs_to_jiffies(BATADV_BLA_PERIOD_LENGTH));
	return 0;
}

/**
 * batadv_bla_check_bcast_duplist
 * @bat_priv: the bat priv with all the soft interface information
 * @skb: contains the bcast_packet to be checked
 *
 * check if it is on our broadcast list. Another gateway might
 * have sent the same packet because it is connected to the same backbone,
 * so we have to remove this duplicate.
 *
 * This is performed by checking the CRC, which will tell us
 * with a good chance that it is the same packet. If it is furthermore
 * sent by another host, drop it. We allow equal packets from
 * the same host however as this might be intended.
 */
int batadv_bla_check_bcast_duplist(struct batadv_priv *bat_priv,
				   struct sk_buff *skb)
{
	int i, curr, ret = 0;
	__be32 crc;
	struct batadv_bcast_packet *bcast_packet;
	struct batadv_bcast_duplist_entry *entry;

	bcast_packet = (struct batadv_bcast_packet *)skb->data;

	/* calculate the crc ... */
	crc = batadv_skb_crc32(skb, (u8 *)(bcast_packet + 1));

	spin_lock_bh(&bat_priv->bla.bcast_duplist_lock);

	for (i = 0; i < BATADV_DUPLIST_SIZE; i++) {
		curr = (bat_priv->bla.bcast_duplist_curr + i);
		curr %= BATADV_DUPLIST_SIZE;
		entry = &bat_priv->bla.bcast_duplist[curr];

		/* we can stop searching if the entry is too old ;
		 * later entries will be even older
		 */
		if (batadv_has_timed_out(entry->entrytime,
					 BATADV_DUPLIST_TIMEOUT))
			break;

		if (entry->crc != crc)
			continue;

		if (batadv_compare_eth(entry->orig, bcast_packet->orig))
			continue;

		/* this entry seems to match: same crc, not too old,
		 * and from another gw. therefore return 1 to forbid it.
		 */
		ret = 1;
		goto out;
	}
	/* not found, add a new entry (overwrite the oldest entry)
	 * and allow it, its the first occurence.
	 */
	curr = (bat_priv->bla.bcast_duplist_curr + BATADV_DUPLIST_SIZE - 1);
	curr %= BATADV_DUPLIST_SIZE;
	entry = &bat_priv->bla.bcast_duplist[curr];
	entry->crc = crc;
	entry->entrytime = jiffies;
	memcpy(entry->orig, bcast_packet->orig, ETH_ALEN);
	bat_priv->bla.bcast_duplist_curr = curr;

out:
	spin_unlock_bh(&bat_priv->bla.bcast_duplist_lock);

	return ret;
}



/* @bat_priv: the bat priv with all the soft interface information
 * @orig: originator mac address
 *
 * check if the originator is a gateway for any VLAN ID.
 *
 * returns 1 if it is found, 0 otherwise
 */
int batadv_bla_is_backbone_gw_orig(struct batadv_priv *bat_priv, uint8_t *orig)
{
	struct batadv_hashtable *hash = bat_priv->bla.backbone_hash;
	struct hlist_head *head;
	struct batadv_bla_backbone_gw *backbone_gw;
	int i;

	if (!atomic_read(&bat_priv->bridge_loop_avoidance))
		return 0;

	if (!hash)
		return 0;

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

		rcu_read_lock();
		hlist_for_each_entry_rcu(backbone_gw, head, hash_entry) {
			if (batadv_compare_eth(backbone_gw->orig, orig)) {
				rcu_read_unlock();
				return 1;
			}
		}
		rcu_read_unlock();
	}

	return 0;
}


/**
 * batadv_bla_is_backbone_gw
 * @skb: the frame to be checked
 * @orig_node: the orig_node of the frame
 * @hdr_size: maximum length of the frame
 *
 * bla_is_backbone_gw inspects the skb for the VLAN ID and returns 1
 * if the orig_node is also a gateway on the soft interface, otherwise it
 * returns 0.
 */
int batadv_bla_is_backbone_gw(struct sk_buff *skb,
			      struct batadv_orig_node *orig_node, int hdr_size)
{
	struct ethhdr *ethhdr;
	struct vlan_ethhdr *vhdr;
	struct batadv_bla_backbone_gw *backbone_gw;
	short vid = -1;

	if (!atomic_read(&orig_node->bat_priv->bridge_loop_avoidance))
		return 0;

	/* first, find out the vid. */
	if (!pskb_may_pull(skb, hdr_size + ETH_HLEN))
		return 0;

	ethhdr = (struct ethhdr *)(((uint8_t *)skb->data) + hdr_size);

	if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) {
		if (!pskb_may_pull(skb, hdr_size + sizeof(struct vlan_ethhdr)))
			return 0;

		vhdr = (struct vlan_ethhdr *)(skb->data + hdr_size);
		vid = ntohs(vhdr->h_vlan_TCI) & VLAN_VID_MASK;
	}

	/* see if this originator is a backbone gw for this VLAN */
	backbone_gw = batadv_backbone_hash_find(orig_node->bat_priv,
						orig_node->orig, vid);
	if (!backbone_gw)
		return 0;

	batadv_backbone_gw_free_ref(backbone_gw);
	return 1;
}

/* free all bla structures (for softinterface free or module unload) */
void batadv_bla_free(struct batadv_priv *bat_priv)
{
	struct batadv_hard_iface *primary_if;

	cancel_delayed_work_sync(&bat_priv->bla.work);
	primary_if = batadv_primary_if_get_selected(bat_priv);

	if (bat_priv->bla.claim_hash) {
		batadv_bla_purge_claims(bat_priv, primary_if, 1);
		batadv_hash_destroy(bat_priv->bla.claim_hash);
		bat_priv->bla.claim_hash = NULL;
	}
	if (bat_priv->bla.backbone_hash) {
		batadv_bla_purge_backbone_gw(bat_priv, 1);
		batadv_hash_destroy(bat_priv->bla.backbone_hash);
		bat_priv->bla.backbone_hash = NULL;
	}
	if (primary_if)
		batadv_hardif_free_ref(primary_if);
}

/**
 * batadv_bla_rx
 * @bat_priv: the bat priv with all the soft interface information
 * @skb: the frame to be checked
 * @vid: the VLAN ID of the frame
 * @is_bcast: the packet came in a broadcast packet type.
 *
 * bla_rx avoidance checks if:
 *  * we have to race for a claim
 *  * if the frame is allowed on the LAN
 *
 * in these cases, the skb is further handled by this function and
 * returns 1, otherwise it returns 0 and the caller shall further
 * process the skb.
 */
int batadv_bla_rx(struct batadv_priv *bat_priv, struct sk_buff *skb, short vid,
		  bool is_bcast)
{
	struct ethhdr *ethhdr;
	struct batadv_bla_claim search_claim, *claim = NULL;
	struct batadv_hard_iface *primary_if;
	int ret;

	ethhdr = (struct ethhdr *)skb_mac_header(skb);

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

	if (!atomic_read(&bat_priv->bridge_loop_avoidance))
		goto allow;


	if (unlikely(atomic_read(&bat_priv->bla.num_requests)))
		/* don't allow broadcasts while requests are in flight */
		if (is_multicast_ether_addr(ethhdr->h_dest) && is_bcast)
			goto handled;

	memcpy(search_claim.addr, ethhdr->h_source, ETH_ALEN);
	search_claim.vid = vid;
	claim = batadv_claim_hash_find(bat_priv, &search_claim);

	if (!claim) {
		/* possible optimization: race for a claim */
		/* No claim exists yet, claim it for us!
		 */
		batadv_handle_claim(bat_priv, primary_if,
				    primary_if->net_dev->dev_addr,
				    ethhdr->h_source, vid);
		goto allow;
	}

	/* if it is our own claim ... */
	if (batadv_compare_eth(claim->backbone_gw->orig,
			       primary_if->net_dev->dev_addr)) {
		/* ... allow it in any case */
		claim->lasttime = jiffies;
		goto allow;
	}

	/* if it is a broadcast ... */
	if (is_multicast_ether_addr(ethhdr->h_dest) && is_bcast) {
		/* ... drop it. the responsible gateway is in charge.
		 *
		 * We need to check is_bcast because with the gateway
		 * feature, broadcasts (like DHCP requests) may be sent
		 * using a unicast packet type.
		 */
		goto handled;
	} else {
		/* seems the client considers us as its best gateway.
		 * send a claim and update the claim table
		 * immediately.
		 */
		batadv_handle_claim(bat_priv, primary_if,
				    primary_if->net_dev->dev_addr,
				    ethhdr->h_source, vid);
		goto allow;
	}
allow:
	batadv_bla_update_own_backbone_gw(bat_priv, primary_if, vid);
	ret = 0;
	goto out;

handled:
	kfree_skb(skb);
	ret = 1;

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

/**
 * batadv_bla_tx
 * @bat_priv: the bat priv with all the soft interface information
 * @skb: the frame to be checked
 * @vid: the VLAN ID of the frame
 *
 * bla_tx checks if:
 *  * a claim was received which has to be processed
 *  * the frame is allowed on the mesh
 *
 * in these cases, the skb is further handled by this function and
 * returns 1, otherwise it returns 0 and the caller shall further
 * process the skb.
 */
int batadv_bla_tx(struct batadv_priv *bat_priv, struct sk_buff *skb, short vid)
{
	struct ethhdr *ethhdr;
	struct batadv_bla_claim search_claim, *claim = NULL;
	struct batadv_hard_iface *primary_if;
	int ret = 0;

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

	if (!atomic_read(&bat_priv->bridge_loop_avoidance))
		goto allow;

	/* in VLAN case, the mac header might not be set. */
	skb_reset_mac_header(skb);

	if (batadv_bla_process_claim(bat_priv, primary_if, skb))
		goto handled;

	ethhdr = (struct ethhdr *)skb_mac_header(skb);

	if (unlikely(atomic_read(&bat_priv->bla.num_requests)))
		/* don't allow broadcasts while requests are in flight */
		if (is_multicast_ether_addr(ethhdr->h_dest))
			goto handled;

	memcpy(search_claim.addr, ethhdr->h_source, ETH_ALEN);
	search_claim.vid = vid;

	claim = batadv_claim_hash_find(bat_priv, &search_claim);

	/* if no claim exists, allow it. */
	if (!claim)
		goto allow;

	/* check if we are responsible. */
	if (batadv_compare_eth(claim->backbone_gw->orig,
			       primary_if->net_dev->dev_addr)) {
		/* if yes, the client has roamed and we have
		 * to unclaim it.
		 */
		batadv_handle_unclaim(bat_priv, primary_if,
				      primary_if->net_dev->dev_addr,
				      ethhdr->h_source, vid);
		goto allow;
	}

	/* check if it is a multicast/broadcast frame */
	if (is_multicast_ether_addr(ethhdr->h_dest)) {
		/* drop it. the responsible gateway has forwarded it into
		 * the backbone network.
		 */
		goto handled;
	} else {
		/* we must allow it. at least if we are
		 * responsible for the DESTINATION.
		 */
		goto allow;
	}
allow:
	batadv_bla_update_own_backbone_gw(bat_priv, primary_if, vid);
	ret = 0;
	goto out;
handled:
	ret = 1;
out:
	if (primary_if)
		batadv_hardif_free_ref(primary_if);
	if (claim)
		batadv_claim_free_ref(claim);
	return ret;
}

int batadv_bla_claim_table_seq_print_text(struct seq_file *seq, void *offset)
{
	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->bla.claim_hash;
	struct batadv_bla_claim *claim;
	struct batadv_hard_iface *primary_if;
	struct hlist_head *head;
	uint32_t i;
	bool is_own;
	uint8_t *primary_addr;

	primary_if = batadv_seq_print_text_primary_if_get(seq);
	if (!primary_if)
		goto out;

	primary_addr = primary_if->net_dev->dev_addr;
	seq_printf(seq,
		   "Claims announced for the mesh %s (orig %pM, group id %#.4x)\n",
		   net_dev->name, primary_addr,
		   ntohs(bat_priv->bla.claim_dest.group));
	seq_printf(seq, "   %-17s    %-5s    %-17s [o] (%-6s)\n",
		   "Client", "VID", "Originator", "CRC");
	for (i = 0; i < hash->size; i++) {
		head = &hash->table[i];

		rcu_read_lock();
		hlist_for_each_entry_rcu(claim, head, hash_entry) {
			is_own = batadv_compare_eth(claim->backbone_gw->orig,
						    primary_addr);
			seq_printf(seq,	" * %pM on % 5d by %pM [%c] (%#.4x)\n",
				   claim->addr, claim->vid,
				   claim->backbone_gw->orig,
				   (is_own ? 'x' : ' '),
				   claim->backbone_gw->crc);
		}
		rcu_read_unlock();
	}
out:
	if (primary_if)
		batadv_hardif_free_ref(primary_if);
	return 0;
}

int batadv_bla_backbone_table_seq_print_text(struct seq_file *seq, void *offset)
{
	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->bla.backbone_hash;
	struct batadv_bla_backbone_gw *backbone_gw;
	struct batadv_hard_iface *primary_if;
	struct hlist_head *head;
	int secs, msecs;
	uint32_t i;
	bool is_own;
	uint8_t *primary_addr;

	primary_if = batadv_seq_print_text_primary_if_get(seq);
	if (!primary_if)
		goto out;

	primary_addr = primary_if->net_dev->dev_addr;
	seq_printf(seq,
		   "Backbones announced for the mesh %s (orig %pM, group id %#.4x)\n",
		   net_dev->name, primary_addr,
		   ntohs(bat_priv->bla.claim_dest.group));
	seq_printf(seq, "   %-17s    %-5s %-9s (%-6s)\n",
		   "Originator", "VID", "last seen", "CRC");
	for (i = 0; i < hash->size; i++) {
		head = &hash->table[i];

		rcu_read_lock();
		hlist_for_each_entry_rcu(backbone_gw, head, hash_entry) {
			msecs = jiffies_to_msecs(jiffies -
						 backbone_gw->lasttime);
			secs = msecs / 1000;
			msecs = msecs % 1000;

			is_own = batadv_compare_eth(backbone_gw->orig,
						    primary_addr);
			if (is_own)
				continue;

			seq_printf(seq,
				   " * %pM on % 5d % 4i.%03is (%#.4x)\n",
				   backbone_gw->orig, backbone_gw->vid,
				   secs, msecs, backbone_gw->crc);
		}
		rcu_read_unlock();
	}
out:
	if (primary_if)
		batadv_hardif_free_ref(primary_if);
	return 0;
}
OpenPOWER on IntegriCloud