summaryrefslogtreecommitdiffstats
path: root/net/bluetooth/6lowpan.c
blob: 58e1b3c97ed7369291468bd808207b301112da6c (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
/*
   Copyright (c) 2013-2014 Intel Corp.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License version 2 and
   only version 2 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.
*/

#include <linux/if_arp.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/module.h>
#include <linux/debugfs.h>

#include <net/ipv6.h>
#include <net/ip6_route.h>
#include <net/addrconf.h>

#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci_core.h>
#include <net/bluetooth/l2cap.h>

#include <net/6lowpan.h> /* for the compression support */

#define VERSION "0.1"

static struct dentry *lowpan_enable_debugfs;
static struct dentry *lowpan_control_debugfs;

#define IFACE_NAME_TEMPLATE "bt%d"

struct skb_cb {
	struct in6_addr addr;
	struct in6_addr gw;
	struct l2cap_chan *chan;
	int status;
};
#define lowpan_cb(skb) ((struct skb_cb *)((skb)->cb))

/* The devices list contains those devices that we are acting
 * as a proxy. The BT 6LoWPAN device is a virtual device that
 * connects to the Bluetooth LE device. The real connection to
 * BT device is done via l2cap layer. There exists one
 * virtual device / one BT 6LoWPAN network (=hciX device).
 * The list contains struct lowpan_dev elements.
 */
static LIST_HEAD(bt_6lowpan_devices);
static DEFINE_SPINLOCK(devices_lock);

static bool enable_6lowpan;

/* We are listening incoming connections via this channel
 */
static struct l2cap_chan *listen_chan;

struct lowpan_peer {
	struct list_head list;
	struct rcu_head rcu;
	struct l2cap_chan *chan;

	/* peer addresses in various formats */
	unsigned char eui64_addr[EUI64_ADDR_LEN];
	struct in6_addr peer_addr;
};

struct lowpan_dev {
	struct list_head list;

	struct hci_dev *hdev;
	struct net_device *netdev;
	struct list_head peers;
	atomic_t peer_count; /* number of items in peers list */

	struct work_struct delete_netdev;
	struct delayed_work notify_peers;
};

static inline struct lowpan_dev *lowpan_dev(const struct net_device *netdev)
{
	return (struct lowpan_dev *)lowpan_priv(netdev)->priv;
}

static inline void peer_add(struct lowpan_dev *dev, struct lowpan_peer *peer)
{
	list_add_rcu(&peer->list, &dev->peers);
	atomic_inc(&dev->peer_count);
}

static inline bool peer_del(struct lowpan_dev *dev, struct lowpan_peer *peer)
{
	list_del_rcu(&peer->list);
	kfree_rcu(peer, rcu);

	module_put(THIS_MODULE);

	if (atomic_dec_and_test(&dev->peer_count)) {
		BT_DBG("last peer");
		return true;
	}

	return false;
}

static inline struct lowpan_peer *peer_lookup_ba(struct lowpan_dev *dev,
						 bdaddr_t *ba, __u8 type)
{
	struct lowpan_peer *peer;

	BT_DBG("peers %d addr %pMR type %d", atomic_read(&dev->peer_count),
	       ba, type);

	rcu_read_lock();

	list_for_each_entry_rcu(peer, &dev->peers, list) {
		BT_DBG("dst addr %pMR dst type %d",
		       &peer->chan->dst, peer->chan->dst_type);

		if (bacmp(&peer->chan->dst, ba))
			continue;

		if (type == peer->chan->dst_type) {
			rcu_read_unlock();
			return peer;
		}
	}

	rcu_read_unlock();

	return NULL;
}

static inline struct lowpan_peer *__peer_lookup_chan(struct lowpan_dev *dev,
						     struct l2cap_chan *chan)
{
	struct lowpan_peer *peer;

	list_for_each_entry_rcu(peer, &dev->peers, list) {
		if (peer->chan == chan)
			return peer;
	}

	return NULL;
}

static inline struct lowpan_peer *__peer_lookup_conn(struct lowpan_dev *dev,
						     struct l2cap_conn *conn)
{
	struct lowpan_peer *peer;

	list_for_each_entry_rcu(peer, &dev->peers, list) {
		if (peer->chan->conn == conn)
			return peer;
	}

	return NULL;
}

static inline struct lowpan_peer *peer_lookup_dst(struct lowpan_dev *dev,
						  struct in6_addr *daddr,
						  struct sk_buff *skb)
{
	struct lowpan_peer *peer;
	struct in6_addr *nexthop;
	struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);
	int count = atomic_read(&dev->peer_count);

	BT_DBG("peers %d addr %pI6c rt %p", count, daddr, rt);

	/* If we have multiple 6lowpan peers, then check where we should
	 * send the packet. If only one peer exists, then we can send the
	 * packet right away.
	 */
	if (count == 1) {
		rcu_read_lock();
		peer = list_first_or_null_rcu(&dev->peers, struct lowpan_peer,
					      list);
		rcu_read_unlock();
		return peer;
	}

	if (!rt) {
		nexthop = &lowpan_cb(skb)->gw;

		if (ipv6_addr_any(nexthop))
			return NULL;
	} else {
		nexthop = rt6_nexthop(rt, daddr);

		/* We need to remember the address because it is needed
		 * by bt_xmit() when sending the packet. In bt_xmit(), the
		 * destination routing info is not set.
		 */
		memcpy(&lowpan_cb(skb)->gw, nexthop, sizeof(struct in6_addr));
	}

	BT_DBG("gw %pI6c", nexthop);

	rcu_read_lock();

	list_for_each_entry_rcu(peer, &dev->peers, list) {
		BT_DBG("dst addr %pMR dst type %d ip %pI6c",
		       &peer->chan->dst, peer->chan->dst_type,
		       &peer->peer_addr);

		if (!ipv6_addr_cmp(&peer->peer_addr, nexthop)) {
			rcu_read_unlock();
			return peer;
		}
	}

	rcu_read_unlock();

	return NULL;
}

static struct lowpan_peer *lookup_peer(struct l2cap_conn *conn)
{
	struct lowpan_dev *entry;
	struct lowpan_peer *peer = NULL;

	rcu_read_lock();

	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
		peer = __peer_lookup_conn(entry, conn);
		if (peer)
			break;
	}

	rcu_read_unlock();

	return peer;
}

static struct lowpan_dev *lookup_dev(struct l2cap_conn *conn)
{
	struct lowpan_dev *entry;
	struct lowpan_dev *dev = NULL;

	rcu_read_lock();

	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
		if (conn->hcon->hdev == entry->hdev) {
			dev = entry;
			break;
		}
	}

	rcu_read_unlock();

	return dev;
}

static int give_skb_to_upper(struct sk_buff *skb, struct net_device *dev)
{
	struct sk_buff *skb_cp;

	skb_cp = skb_copy(skb, GFP_ATOMIC);
	if (!skb_cp)
		return NET_RX_DROP;

	return netif_rx_ni(skb_cp);
}

static int iphc_decompress(struct sk_buff *skb, struct net_device *netdev,
			   struct l2cap_chan *chan)
{
	const u8 *saddr, *daddr;
	struct lowpan_dev *dev;
	struct lowpan_peer *peer;

	dev = lowpan_dev(netdev);

	rcu_read_lock();
	peer = __peer_lookup_chan(dev, chan);
	rcu_read_unlock();
	if (!peer)
		return -EINVAL;

	saddr = peer->eui64_addr;
	daddr = dev->netdev->dev_addr;

	return lowpan_header_decompress(skb, netdev, daddr, saddr);
}

static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
		    struct l2cap_chan *chan)
{
	struct sk_buff *local_skb;
	int ret;

	if (!netif_running(dev))
		goto drop;

	if (dev->type != ARPHRD_6LOWPAN || !skb->len)
		goto drop;

	skb_reset_network_header(skb);

	skb = skb_share_check(skb, GFP_ATOMIC);
	if (!skb)
		goto drop;

	/* check that it's our buffer */
	if (lowpan_is_ipv6(*skb_network_header(skb))) {
		/* Copy the packet so that the IPv6 header is
		 * properly aligned.
		 */
		local_skb = skb_copy_expand(skb, NET_SKB_PAD - 1,
					    skb_tailroom(skb), GFP_ATOMIC);
		if (!local_skb)
			goto drop;

		local_skb->protocol = htons(ETH_P_IPV6);
		local_skb->pkt_type = PACKET_HOST;
		local_skb->dev = dev;

		skb_set_transport_header(local_skb, sizeof(struct ipv6hdr));

		if (give_skb_to_upper(local_skb, dev) != NET_RX_SUCCESS) {
			kfree_skb(local_skb);
			goto drop;
		}

		dev->stats.rx_bytes += skb->len;
		dev->stats.rx_packets++;

		consume_skb(local_skb);
		consume_skb(skb);
	} else if (lowpan_is_iphc(*skb_network_header(skb))) {
		local_skb = skb_clone(skb, GFP_ATOMIC);
		if (!local_skb)
			goto drop;

		local_skb->dev = dev;

		ret = iphc_decompress(local_skb, dev, chan);
		if (ret < 0) {
			kfree_skb(local_skb);
			goto drop;
		}

		local_skb->protocol = htons(ETH_P_IPV6);
		local_skb->pkt_type = PACKET_HOST;

		if (give_skb_to_upper(local_skb, dev)
				!= NET_RX_SUCCESS) {
			kfree_skb(local_skb);
			goto drop;
		}

		dev->stats.rx_bytes += skb->len;
		dev->stats.rx_packets++;

		consume_skb(local_skb);
		consume_skb(skb);
	} else {
		goto drop;
	}

	return NET_RX_SUCCESS;

drop:
	dev->stats.rx_dropped++;
	return NET_RX_DROP;
}

/* Packet from BT LE device */
static int chan_recv_cb(struct l2cap_chan *chan, struct sk_buff *skb)
{
	struct lowpan_dev *dev;
	struct lowpan_peer *peer;
	int err;

	peer = lookup_peer(chan->conn);
	if (!peer)
		return -ENOENT;

	dev = lookup_dev(chan->conn);
	if (!dev || !dev->netdev)
		return -ENOENT;

	err = recv_pkt(skb, dev->netdev, chan);
	if (err) {
		BT_DBG("recv pkt %d", err);
		err = -EAGAIN;
	}

	return err;
}

static u8 get_addr_type_from_eui64(u8 byte)
{
	/* Is universal(0) or local(1) bit */
	return ((byte & 0x02) ? BDADDR_LE_RANDOM : BDADDR_LE_PUBLIC);
}

static void copy_to_bdaddr(struct in6_addr *ip6_daddr, bdaddr_t *addr)
{
	u8 *eui64 = ip6_daddr->s6_addr + 8;

	addr->b[0] = eui64[7];
	addr->b[1] = eui64[6];
	addr->b[2] = eui64[5];
	addr->b[3] = eui64[2];
	addr->b[4] = eui64[1];
	addr->b[5] = eui64[0];
}

static void convert_dest_bdaddr(struct in6_addr *ip6_daddr,
				bdaddr_t *addr, u8 *addr_type)
{
	copy_to_bdaddr(ip6_daddr, addr);

	/* We need to toggle the U/L bit that we got from IPv6 address
	 * so that we get the proper address and type of the BD address.
	 */
	addr->b[5] ^= 0x02;

	*addr_type = get_addr_type_from_eui64(addr->b[5]);
}

static int setup_header(struct sk_buff *skb, struct net_device *netdev,
			bdaddr_t *peer_addr, u8 *peer_addr_type)
{
	struct in6_addr ipv6_daddr;
	struct lowpan_dev *dev;
	struct lowpan_peer *peer;
	bdaddr_t addr, *any = BDADDR_ANY;
	u8 *daddr = any->b;
	int err, status = 0;

	dev = lowpan_dev(netdev);

	memcpy(&ipv6_daddr, &lowpan_cb(skb)->addr, sizeof(ipv6_daddr));

	if (ipv6_addr_is_multicast(&ipv6_daddr)) {
		lowpan_cb(skb)->chan = NULL;
	} else {
		u8 addr_type;

		/* Get destination BT device from skb.
		 * If there is no such peer then discard the packet.
		 */
		convert_dest_bdaddr(&ipv6_daddr, &addr, &addr_type);

		BT_DBG("dest addr %pMR type %d IP %pI6c", &addr,
		       addr_type, &ipv6_daddr);

		peer = peer_lookup_ba(dev, &addr, addr_type);
		if (!peer) {
			/* The packet might be sent to 6lowpan interface
			 * because of routing (either via default route
			 * or user set route) so get peer according to
			 * the destination address.
			 */
			peer = peer_lookup_dst(dev, &ipv6_daddr, skb);
			if (!peer) {
				BT_DBG("no such peer %pMR found", &addr);
				return -ENOENT;
			}
		}

		daddr = peer->eui64_addr;
		*peer_addr = addr;
		*peer_addr_type = addr_type;
		lowpan_cb(skb)->chan = peer->chan;

		status = 1;
	}

	lowpan_header_compress(skb, netdev, daddr, dev->netdev->dev_addr);

	err = dev_hard_header(skb, netdev, ETH_P_IPV6, NULL, NULL, 0);
	if (err < 0)
		return err;

	return status;
}

static int header_create(struct sk_buff *skb, struct net_device *netdev,
			 unsigned short type, const void *_daddr,
			 const void *_saddr, unsigned int len)
{
	struct ipv6hdr *hdr;

	if (type != ETH_P_IPV6)
		return -EINVAL;

	hdr = ipv6_hdr(skb);

	memcpy(&lowpan_cb(skb)->addr, &hdr->daddr, sizeof(struct in6_addr));

	return 0;
}

/* Packet to BT LE device */
static int send_pkt(struct l2cap_chan *chan, struct sk_buff *skb,
		    struct net_device *netdev)
{
	struct msghdr msg;
	struct kvec iv;
	int err;

	/* Remember the skb so that we can send EAGAIN to the caller if
	 * we run out of credits.
	 */
	chan->data = skb;

	iv.iov_base = skb->data;
	iv.iov_len = skb->len;

	memset(&msg, 0, sizeof(msg));
	iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, &iv, 1, skb->len);

	err = l2cap_chan_send(chan, &msg, skb->len);
	if (err > 0) {
		netdev->stats.tx_bytes += err;
		netdev->stats.tx_packets++;
		return 0;
	}

	if (!err)
		err = lowpan_cb(skb)->status;

	if (err < 0) {
		if (err == -EAGAIN)
			netdev->stats.tx_dropped++;
		else
			netdev->stats.tx_errors++;
	}

	return err;
}

static int send_mcast_pkt(struct sk_buff *skb, struct net_device *netdev)
{
	struct sk_buff *local_skb;
	struct lowpan_dev *entry;
	int err = 0;

	rcu_read_lock();

	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
		struct lowpan_peer *pentry;
		struct lowpan_dev *dev;

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

		dev = lowpan_dev(entry->netdev);

		list_for_each_entry_rcu(pentry, &dev->peers, list) {
			int ret;

			local_skb = skb_clone(skb, GFP_ATOMIC);

			BT_DBG("xmit %s to %pMR type %d IP %pI6c chan %p",
			       netdev->name,
			       &pentry->chan->dst, pentry->chan->dst_type,
			       &pentry->peer_addr, pentry->chan);
			ret = send_pkt(pentry->chan, local_skb, netdev);
			if (ret < 0)
				err = ret;

			kfree_skb(local_skb);
		}
	}

	rcu_read_unlock();

	return err;
}

static netdev_tx_t bt_xmit(struct sk_buff *skb, struct net_device *netdev)
{
	int err = 0;
	bdaddr_t addr;
	u8 addr_type;

	/* We must take a copy of the skb before we modify/replace the ipv6
	 * header as the header could be used elsewhere
	 */
	skb = skb_unshare(skb, GFP_ATOMIC);
	if (!skb)
		return NET_XMIT_DROP;

	/* Return values from setup_header()
	 *  <0 - error, packet is dropped
	 *   0 - this is a multicast packet
	 *   1 - this is unicast packet
	 */
	err = setup_header(skb, netdev, &addr, &addr_type);
	if (err < 0) {
		kfree_skb(skb);
		return NET_XMIT_DROP;
	}

	if (err) {
		if (lowpan_cb(skb)->chan) {
			BT_DBG("xmit %s to %pMR type %d IP %pI6c chan %p",
			       netdev->name, &addr, addr_type,
			       &lowpan_cb(skb)->addr, lowpan_cb(skb)->chan);
			err = send_pkt(lowpan_cb(skb)->chan, skb, netdev);
		} else {
			err = -ENOENT;
		}
	} else {
		/* We need to send the packet to every device behind this
		 * interface.
		 */
		err = send_mcast_pkt(skb, netdev);
	}

	dev_kfree_skb(skb);

	if (err)
		BT_DBG("ERROR: xmit failed (%d)", err);

	return err < 0 ? NET_XMIT_DROP : err;
}

static struct lock_class_key bt_tx_busylock;
static struct lock_class_key bt_netdev_xmit_lock_key;

static void bt_set_lockdep_class_one(struct net_device *dev,
				     struct netdev_queue *txq,
				     void *_unused)
{
	lockdep_set_class(&txq->_xmit_lock, &bt_netdev_xmit_lock_key);
}

static int bt_dev_init(struct net_device *dev)
{
	netdev_for_each_tx_queue(dev, bt_set_lockdep_class_one, NULL);
	dev->qdisc_tx_busylock = &bt_tx_busylock;

	return 0;
}

static const struct net_device_ops netdev_ops = {
	.ndo_init		= bt_dev_init,
	.ndo_start_xmit		= bt_xmit,
};

static struct header_ops header_ops = {
	.create	= header_create,
};

static void netdev_setup(struct net_device *dev)
{
	dev->hard_header_len	= 0;
	dev->needed_tailroom	= 0;
	dev->flags		= IFF_RUNNING | IFF_POINTOPOINT |
				  IFF_MULTICAST;
	dev->watchdog_timeo	= 0;

	dev->netdev_ops		= &netdev_ops;
	dev->header_ops		= &header_ops;
	dev->destructor		= free_netdev;
}

static struct device_type bt_type = {
	.name	= "bluetooth",
};

static void set_addr(u8 *eui, u8 *addr, u8 addr_type)
{
	/* addr is the BT address in little-endian format */
	eui[0] = addr[5];
	eui[1] = addr[4];
	eui[2] = addr[3];
	eui[3] = 0xFF;
	eui[4] = 0xFE;
	eui[5] = addr[2];
	eui[6] = addr[1];
	eui[7] = addr[0];

	/* Universal/local bit set, BT 6lowpan draft ch. 3.2.1 */
	if (addr_type == BDADDR_LE_PUBLIC)
		eui[0] &= ~0x02;
	else
		eui[0] |= 0x02;

	BT_DBG("type %d addr %*phC", addr_type, 8, eui);
}

static void set_dev_addr(struct net_device *netdev, bdaddr_t *addr,
		         u8 addr_type)
{
	netdev->addr_assign_type = NET_ADDR_PERM;
	set_addr(netdev->dev_addr, addr->b, addr_type);
}

static void ifup(struct net_device *netdev)
{
	int err;

	rtnl_lock();
	err = dev_open(netdev);
	if (err < 0)
		BT_INFO("iface %s cannot be opened (%d)", netdev->name, err);
	rtnl_unlock();
}

static void ifdown(struct net_device *netdev)
{
	int err;

	rtnl_lock();
	err = dev_close(netdev);
	if (err < 0)
		BT_INFO("iface %s cannot be closed (%d)", netdev->name, err);
	rtnl_unlock();
}

static void do_notify_peers(struct work_struct *work)
{
	struct lowpan_dev *dev = container_of(work, struct lowpan_dev,
					      notify_peers.work);

	netdev_notify_peers(dev->netdev); /* send neighbour adv at startup */
}

static bool is_bt_6lowpan(struct hci_conn *hcon)
{
	if (hcon->type != LE_LINK)
		return false;

	if (!enable_6lowpan)
		return false;

	return true;
}

static struct l2cap_chan *chan_create(void)
{
	struct l2cap_chan *chan;

	chan = l2cap_chan_create();
	if (!chan)
		return NULL;

	l2cap_chan_set_defaults(chan);

	chan->chan_type = L2CAP_CHAN_CONN_ORIENTED;
	chan->mode = L2CAP_MODE_LE_FLOWCTL;
	chan->imtu = 1280;

	return chan;
}

static void set_ip_addr_bits(u8 addr_type, u8 *addr)
{
	if (addr_type == BDADDR_LE_PUBLIC)
		*addr |= 0x02;
	else
		*addr &= ~0x02;
}

static struct l2cap_chan *add_peer_chan(struct l2cap_chan *chan,
					struct lowpan_dev *dev)
{
	struct lowpan_peer *peer;

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

	peer->chan = chan;
	memset(&peer->peer_addr, 0, sizeof(struct in6_addr));

	/* RFC 2464 ch. 5 */
	peer->peer_addr.s6_addr[0] = 0xFE;
	peer->peer_addr.s6_addr[1] = 0x80;
	set_addr((u8 *)&peer->peer_addr.s6_addr + 8, chan->dst.b,
		 chan->dst_type);

	memcpy(&peer->eui64_addr, (u8 *)&peer->peer_addr.s6_addr + 8,
	       EUI64_ADDR_LEN);

	/* IPv6 address needs to have the U/L bit set properly so toggle
	 * it back here.
	 */
	set_ip_addr_bits(chan->dst_type, (u8 *)&peer->peer_addr.s6_addr + 8);

	spin_lock(&devices_lock);
	INIT_LIST_HEAD(&peer->list);
	peer_add(dev, peer);
	spin_unlock(&devices_lock);

	/* Notifying peers about us needs to be done without locks held */
	INIT_DELAYED_WORK(&dev->notify_peers, do_notify_peers);
	schedule_delayed_work(&dev->notify_peers, msecs_to_jiffies(100));

	return peer->chan;
}

static int setup_netdev(struct l2cap_chan *chan, struct lowpan_dev **dev)
{
	struct net_device *netdev;
	int err = 0;

	netdev = alloc_netdev(LOWPAN_PRIV_SIZE(sizeof(struct lowpan_dev)),
			      IFACE_NAME_TEMPLATE, NET_NAME_UNKNOWN,
			      netdev_setup);
	if (!netdev)
		return -ENOMEM;

	set_dev_addr(netdev, &chan->src, chan->src_type);

	netdev->netdev_ops = &netdev_ops;
	SET_NETDEV_DEV(netdev, &chan->conn->hcon->hdev->dev);
	SET_NETDEV_DEVTYPE(netdev, &bt_type);

	*dev = lowpan_dev(netdev);
	(*dev)->netdev = netdev;
	(*dev)->hdev = chan->conn->hcon->hdev;
	INIT_LIST_HEAD(&(*dev)->peers);

	spin_lock(&devices_lock);
	INIT_LIST_HEAD(&(*dev)->list);
	list_add_rcu(&(*dev)->list, &bt_6lowpan_devices);
	spin_unlock(&devices_lock);

	err = lowpan_register_netdev(netdev, LOWPAN_LLTYPE_BTLE);
	if (err < 0) {
		BT_INFO("register_netdev failed %d", err);
		spin_lock(&devices_lock);
		list_del_rcu(&(*dev)->list);
		spin_unlock(&devices_lock);
		free_netdev(netdev);
		goto out;
	}

	BT_DBG("ifindex %d peer bdaddr %pMR type %d my addr %pMR type %d",
	       netdev->ifindex, &chan->dst, chan->dst_type,
	       &chan->src, chan->src_type);
	set_bit(__LINK_STATE_PRESENT, &netdev->state);

	return 0;

out:
	return err;
}

static inline void chan_ready_cb(struct l2cap_chan *chan)
{
	struct lowpan_dev *dev;

	dev = lookup_dev(chan->conn);

	BT_DBG("chan %p conn %p dev %p", chan, chan->conn, dev);

	if (!dev) {
		if (setup_netdev(chan, &dev) < 0) {
			l2cap_chan_del(chan, -ENOENT);
			return;
		}
	}

	if (!try_module_get(THIS_MODULE))
		return;

	add_peer_chan(chan, dev);
	ifup(dev->netdev);
}

static inline struct l2cap_chan *chan_new_conn_cb(struct l2cap_chan *pchan)
{
	struct l2cap_chan *chan;

	chan = chan_create();
	if (!chan)
		return NULL;

	chan->ops = pchan->ops;

	BT_DBG("chan %p pchan %p", chan, pchan);

	return chan;
}

static void delete_netdev(struct work_struct *work)
{
	struct lowpan_dev *entry = container_of(work, struct lowpan_dev,
						delete_netdev);

	lowpan_unregister_netdev(entry->netdev);

	/* The entry pointer is deleted by the netdev destructor. */
}

static void chan_close_cb(struct l2cap_chan *chan)
{
	struct lowpan_dev *entry;
	struct lowpan_dev *dev = NULL;
	struct lowpan_peer *peer;
	int err = -ENOENT;
	bool last = false, remove = true;

	BT_DBG("chan %p conn %p", chan, chan->conn);

	if (chan->conn && chan->conn->hcon) {
		if (!is_bt_6lowpan(chan->conn->hcon))
			return;

		/* If conn is set, then the netdev is also there and we should
		 * not remove it.
		 */
		remove = false;
	}

	spin_lock(&devices_lock);

	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
		dev = lowpan_dev(entry->netdev);
		peer = __peer_lookup_chan(dev, chan);
		if (peer) {
			last = peer_del(dev, peer);
			err = 0;

			BT_DBG("dev %p removing %speer %p", dev,
			       last ? "last " : "1 ", peer);
			BT_DBG("chan %p orig refcnt %d", chan,
			       atomic_read(&chan->kref.refcount));

			l2cap_chan_put(chan);
			break;
		}
	}

	if (!err && last && dev && !atomic_read(&dev->peer_count)) {
		spin_unlock(&devices_lock);

		cancel_delayed_work_sync(&dev->notify_peers);

		ifdown(dev->netdev);

		if (remove) {
			INIT_WORK(&entry->delete_netdev, delete_netdev);
			schedule_work(&entry->delete_netdev);
		}
	} else {
		spin_unlock(&devices_lock);
	}

	return;
}

static void chan_state_change_cb(struct l2cap_chan *chan, int state, int err)
{
	BT_DBG("chan %p conn %p state %s err %d", chan, chan->conn,
	       state_to_string(state), err);
}

static struct sk_buff *chan_alloc_skb_cb(struct l2cap_chan *chan,
					 unsigned long hdr_len,
					 unsigned long len, int nb)
{
	/* Note that we must allocate using GFP_ATOMIC here as
	 * this function is called originally from netdev hard xmit
	 * function in atomic context.
	 */
	return bt_skb_alloc(hdr_len + len, GFP_ATOMIC);
}

static void chan_suspend_cb(struct l2cap_chan *chan)
{
	struct sk_buff *skb = chan->data;

	BT_DBG("chan %p conn %p skb %p", chan, chan->conn, skb);

	if (!skb)
		return;

	lowpan_cb(skb)->status = -EAGAIN;
}

static void chan_resume_cb(struct l2cap_chan *chan)
{
	struct sk_buff *skb = chan->data;

	BT_DBG("chan %p conn %p skb %p", chan, chan->conn, skb);

	if (!skb)
		return;

	lowpan_cb(skb)->status = 0;
}

static long chan_get_sndtimeo_cb(struct l2cap_chan *chan)
{
	return L2CAP_CONN_TIMEOUT;
}

static const struct l2cap_ops bt_6lowpan_chan_ops = {
	.name			= "L2CAP 6LoWPAN channel",
	.new_connection		= chan_new_conn_cb,
	.recv			= chan_recv_cb,
	.close			= chan_close_cb,
	.state_change		= chan_state_change_cb,
	.ready			= chan_ready_cb,
	.resume			= chan_resume_cb,
	.suspend		= chan_suspend_cb,
	.get_sndtimeo		= chan_get_sndtimeo_cb,
	.alloc_skb		= chan_alloc_skb_cb,

	.teardown		= l2cap_chan_no_teardown,
	.defer			= l2cap_chan_no_defer,
	.set_shutdown		= l2cap_chan_no_set_shutdown,
};

static inline __u8 bdaddr_type(__u8 type)
{
	if (type == ADDR_LE_DEV_PUBLIC)
		return BDADDR_LE_PUBLIC;
	else
		return BDADDR_LE_RANDOM;
}

static int bt_6lowpan_connect(bdaddr_t *addr, u8 dst_type)
{
	struct l2cap_chan *chan;
	int err;

	chan = chan_create();
	if (!chan)
		return -EINVAL;

	chan->ops = &bt_6lowpan_chan_ops;

	err = l2cap_chan_connect(chan, cpu_to_le16(L2CAP_PSM_IPSP), 0,
				 addr, dst_type);

	BT_DBG("chan %p err %d", chan, err);
	if (err < 0)
		l2cap_chan_put(chan);

	return err;
}

static int bt_6lowpan_disconnect(struct l2cap_conn *conn, u8 dst_type)
{
	struct lowpan_peer *peer;

	BT_DBG("conn %p dst type %d", conn, dst_type);

	peer = lookup_peer(conn);
	if (!peer)
		return -ENOENT;

	BT_DBG("peer %p chan %p", peer, peer->chan);

	l2cap_chan_close(peer->chan, ENOENT);

	return 0;
}

static struct l2cap_chan *bt_6lowpan_listen(void)
{
	bdaddr_t *addr = BDADDR_ANY;
	struct l2cap_chan *chan;
	int err;

	if (!enable_6lowpan)
		return NULL;

	chan = chan_create();
	if (!chan)
		return NULL;

	chan->ops = &bt_6lowpan_chan_ops;
	chan->state = BT_LISTEN;
	chan->src_type = BDADDR_LE_PUBLIC;

	atomic_set(&chan->nesting, L2CAP_NESTING_PARENT);

	BT_DBG("chan %p src type %d", chan, chan->src_type);

	err = l2cap_add_psm(chan, addr, cpu_to_le16(L2CAP_PSM_IPSP));
	if (err) {
		l2cap_chan_put(chan);
		BT_ERR("psm cannot be added err %d", err);
		return NULL;
	}

	return chan;
}

static int get_l2cap_conn(char *buf, bdaddr_t *addr, u8 *addr_type,
			  struct l2cap_conn **conn)
{
	struct hci_conn *hcon;
	struct hci_dev *hdev;
	bdaddr_t *src = BDADDR_ANY;
	int n;

	n = sscanf(buf, "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx %hhu",
		   &addr->b[5], &addr->b[4], &addr->b[3],
		   &addr->b[2], &addr->b[1], &addr->b[0],
		   addr_type);

	if (n < 7)
		return -EINVAL;

	hdev = hci_get_route(addr, src);
	if (!hdev)
		return -ENOENT;

	hci_dev_lock(hdev);
	hcon = hci_conn_hash_lookup_le(hdev, addr, *addr_type);
	hci_dev_unlock(hdev);

	if (!hcon)
		return -ENOENT;

	*conn = (struct l2cap_conn *)hcon->l2cap_data;

	BT_DBG("conn %p dst %pMR type %d", *conn, &hcon->dst, hcon->dst_type);

	return 0;
}

static void disconnect_all_peers(void)
{
	struct lowpan_dev *entry;
	struct lowpan_peer *peer, *tmp_peer, *new_peer;
	struct list_head peers;

	INIT_LIST_HEAD(&peers);

	/* We make a separate list of peers as the close_cb() will
	 * modify the device peers list so it is better not to mess
	 * with the same list at the same time.
	 */

	rcu_read_lock();

	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
		list_for_each_entry_rcu(peer, &entry->peers, list) {
			new_peer = kmalloc(sizeof(*new_peer), GFP_ATOMIC);
			if (!new_peer)
				break;

			new_peer->chan = peer->chan;
			INIT_LIST_HEAD(&new_peer->list);

			list_add(&new_peer->list, &peers);
		}
	}

	rcu_read_unlock();

	spin_lock(&devices_lock);
	list_for_each_entry_safe(peer, tmp_peer, &peers, list) {
		l2cap_chan_close(peer->chan, ENOENT);

		list_del_rcu(&peer->list);
		kfree_rcu(peer, rcu);
	}
	spin_unlock(&devices_lock);
}

struct set_enable {
	struct work_struct work;
	bool flag;
};

static void do_enable_set(struct work_struct *work)
{
	struct set_enable *set_enable = container_of(work,
						     struct set_enable, work);

	if (!set_enable->flag || enable_6lowpan != set_enable->flag)
		/* Disconnect existing connections if 6lowpan is
		 * disabled
		 */
		disconnect_all_peers();

	enable_6lowpan = set_enable->flag;

	if (listen_chan) {
		l2cap_chan_close(listen_chan, 0);
		l2cap_chan_put(listen_chan);
	}

	listen_chan = bt_6lowpan_listen();

	kfree(set_enable);
}

static int lowpan_enable_set(void *data, u64 val)
{
	struct set_enable *set_enable;

	set_enable = kzalloc(sizeof(*set_enable), GFP_KERNEL);
	if (!set_enable)
		return -ENOMEM;

	set_enable->flag = !!val;
	INIT_WORK(&set_enable->work, do_enable_set);

	schedule_work(&set_enable->work);

	return 0;
}

static int lowpan_enable_get(void *data, u64 *val)
{
	*val = enable_6lowpan;
	return 0;
}

DEFINE_SIMPLE_ATTRIBUTE(lowpan_enable_fops, lowpan_enable_get,
			lowpan_enable_set, "%llu\n");

static ssize_t lowpan_control_write(struct file *fp,
				    const char __user *user_buffer,
				    size_t count,
				    loff_t *position)
{
	char buf[32];
	size_t buf_size = min(count, sizeof(buf) - 1);
	int ret;
	bdaddr_t addr;
	u8 addr_type;
	struct l2cap_conn *conn = NULL;

	if (copy_from_user(buf, user_buffer, buf_size))
		return -EFAULT;

	buf[buf_size] = '\0';

	if (memcmp(buf, "connect ", 8) == 0) {
		ret = get_l2cap_conn(&buf[8], &addr, &addr_type, &conn);
		if (ret == -EINVAL)
			return ret;

		if (listen_chan) {
			l2cap_chan_close(listen_chan, 0);
			l2cap_chan_put(listen_chan);
			listen_chan = NULL;
		}

		if (conn) {
			struct lowpan_peer *peer;

			if (!is_bt_6lowpan(conn->hcon))
				return -EINVAL;

			peer = lookup_peer(conn);
			if (peer) {
				BT_DBG("6LoWPAN connection already exists");
				return -EALREADY;
			}

			BT_DBG("conn %p dst %pMR type %d user %d", conn,
			       &conn->hcon->dst, conn->hcon->dst_type,
			       addr_type);
		}

		ret = bt_6lowpan_connect(&addr, addr_type);
		if (ret < 0)
			return ret;

		return count;
	}

	if (memcmp(buf, "disconnect ", 11) == 0) {
		ret = get_l2cap_conn(&buf[11], &addr, &addr_type, &conn);
		if (ret < 0)
			return ret;

		ret = bt_6lowpan_disconnect(conn, addr_type);
		if (ret < 0)
			return ret;

		return count;
	}

	return count;
}

static int lowpan_control_show(struct seq_file *f, void *ptr)
{
	struct lowpan_dev *entry;
	struct lowpan_peer *peer;

	spin_lock(&devices_lock);

	list_for_each_entry(entry, &bt_6lowpan_devices, list) {
		list_for_each_entry(peer, &entry->peers, list)
			seq_printf(f, "%pMR (type %u)\n",
				   &peer->chan->dst, peer->chan->dst_type);
	}

	spin_unlock(&devices_lock);

	return 0;
}

static int lowpan_control_open(struct inode *inode, struct file *file)
{
	return single_open(file, lowpan_control_show, inode->i_private);
}

static const struct file_operations lowpan_control_fops = {
	.open		= lowpan_control_open,
	.read		= seq_read,
	.write		= lowpan_control_write,
	.llseek		= seq_lseek,
	.release	= single_release,
};

static void disconnect_devices(void)
{
	struct lowpan_dev *entry, *tmp, *new_dev;
	struct list_head devices;

	INIT_LIST_HEAD(&devices);

	/* We make a separate list of devices because the unregister_netdev()
	 * will call device_event() which will also want to modify the same
	 * devices list.
	 */

	rcu_read_lock();

	list_for_each_entry_rcu(entry, &bt_6lowpan_devices, list) {
		new_dev = kmalloc(sizeof(*new_dev), GFP_ATOMIC);
		if (!new_dev)
			break;

		new_dev->netdev = entry->netdev;
		INIT_LIST_HEAD(&new_dev->list);

		list_add_rcu(&new_dev->list, &devices);
	}

	rcu_read_unlock();

	list_for_each_entry_safe(entry, tmp, &devices, list) {
		ifdown(entry->netdev);
		BT_DBG("Unregistering netdev %s %p",
		       entry->netdev->name, entry->netdev);
		lowpan_unregister_netdev(entry->netdev);
		kfree(entry);
	}
}

static int device_event(struct notifier_block *unused,
			unsigned long event, void *ptr)
{
	struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
	struct lowpan_dev *entry;

	if (netdev->type != ARPHRD_6LOWPAN)
		return NOTIFY_DONE;

	switch (event) {
	case NETDEV_UNREGISTER:
		spin_lock(&devices_lock);
		list_for_each_entry(entry, &bt_6lowpan_devices, list) {
			if (entry->netdev == netdev) {
				BT_DBG("Unregistered netdev %s %p",
				       netdev->name, netdev);
				list_del(&entry->list);
				break;
			}
		}
		spin_unlock(&devices_lock);
		break;
	}

	return NOTIFY_DONE;
}

static struct notifier_block bt_6lowpan_dev_notifier = {
	.notifier_call = device_event,
};

static int __init bt_6lowpan_init(void)
{
	lowpan_enable_debugfs = debugfs_create_file("6lowpan_enable", 0644,
						    bt_debugfs, NULL,
						    &lowpan_enable_fops);
	lowpan_control_debugfs = debugfs_create_file("6lowpan_control", 0644,
						     bt_debugfs, NULL,
						     &lowpan_control_fops);

	return register_netdevice_notifier(&bt_6lowpan_dev_notifier);
}

static void __exit bt_6lowpan_exit(void)
{
	debugfs_remove(lowpan_enable_debugfs);
	debugfs_remove(lowpan_control_debugfs);

	if (listen_chan) {
		l2cap_chan_close(listen_chan, 0);
		l2cap_chan_put(listen_chan);
	}

	disconnect_devices();

	unregister_netdevice_notifier(&bt_6lowpan_dev_notifier);
}

module_init(bt_6lowpan_init);
module_exit(bt_6lowpan_exit);

MODULE_AUTHOR("Jukka Rissanen <jukka.rissanen@linux.intel.com>");
MODULE_DESCRIPTION("Bluetooth 6LoWPAN");
MODULE_VERSION(VERSION);
MODULE_LICENSE("GPL");