aboutsummaryrefslogtreecommitdiff
path: root/net/ieee802154/6lowpan.c
blob: 459e200c08a40e4e737798582524cd973064b143 (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
/*
 * Copyright 2011, Siemens AG
 * written by Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
 */

/*
 * Based on patches from Jon Smirl <jonsmirl@gmail.com>
 * Copyright (c) 2011 Jon Smirl <jonsmirl@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License 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.
 *
 * 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.
 */

/* Jon's code is based on 6lowpan implementation for Contiki which is:
 * Copyright (c) 2008, Swedish Institute of Computer Science.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <linux/bitops.h>
#include <linux/if_arp.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/netdevice.h>
#include <net/af_ieee802154.h>
#include <net/ieee802154.h>
#include <net/ieee802154_netdev.h>
#include <net/ipv6.h>

#include "6lowpan.h"

/* TTL uncompression values */
static const u8 lowpan_ttl_values[] = {0, 1, 64, 255};

static LIST_HEAD(lowpan_devices);

/* private device info */
struct lowpan_dev_info {
	struct net_device	*real_dev; /* real WPAN device ptr */
	struct mutex		dev_list_mtx; /* mutex for list ops */
	unsigned short		fragment_tag;
};

struct lowpan_dev_record {
	struct net_device *ldev;
	struct list_head list;
};

struct lowpan_fragment {
	struct sk_buff		*skb;		/* skb to be assembled */
	u16			length;		/* length to be assemled */
	u32			bytes_rcv;	/* bytes received */
	u16			tag;		/* current fragment tag */
	struct timer_list	timer;		/* assembling timer */
	struct list_head	list;		/* fragments list */
};

static LIST_HEAD(lowpan_fragments);
static DEFINE_SPINLOCK(flist_lock);

static inline struct
lowpan_dev_info *lowpan_dev_info(const struct net_device *dev)
{
	return netdev_priv(dev);
}

static inline void lowpan_address_flip(u8 *src, u8 *dest)
{
	int i;
	for (i = 0; i < IEEE802154_ADDR_LEN; i++)
		(dest)[IEEE802154_ADDR_LEN - i - 1] = (src)[i];
}

/* list of all 6lowpan devices, uses for package delivering */
/* print data in line */
static inline void lowpan_raw_dump_inline(const char *caller, char *msg,
				   unsigned char *buf, int len)
{
#ifdef DEBUG
	if (msg)
		pr_debug("(%s) %s: ", caller, msg);
	print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_NONE,
		       16, 1, buf, len, false);
#endif /* DEBUG */
}

/*
 * print data in a table format:
 *
 * addr: xx xx xx xx xx xx
 * addr: xx xx xx xx xx xx
 * ...
 */
static inline void lowpan_raw_dump_table(const char *caller, char *msg,
				   unsigned char *buf, int len)
{
#ifdef DEBUG
	if (msg)
		pr_debug("(%s) %s:\n", caller, msg);
	print_hex_dump(KERN_DEBUG, "\t", DUMP_PREFIX_OFFSET,
		       16, 1, buf, len, false);
#endif /* DEBUG */
}

static u8
lowpan_compress_addr_64(u8 **hc06_ptr, u8 shift, const struct in6_addr *ipaddr,
		 const unsigned char *lladdr)
{
	u8 val = 0;

	if (is_addr_mac_addr_based(ipaddr, lladdr))
		val = 3; /* 0-bits */
	else if (lowpan_is_iid_16_bit_compressable(ipaddr)) {
		/* compress IID to 16 bits xxxx::XXXX */
		memcpy(*hc06_ptr, &ipaddr->s6_addr16[7], 2);
		*hc06_ptr += 2;
		val = 2; /* 16-bits */
	} else {
		/* do not compress IID => xxxx::IID */
		memcpy(*hc06_ptr, &ipaddr->s6_addr16[4], 8);
		*hc06_ptr += 8;
		val = 1; /* 64-bits */
	}

	return rol8(val, shift);
}

/*
 * Uncompress address function for source and
 * destination address(non-multicast).
 *
 * address_mode is sam value or dam value.
 */
static int
lowpan_uncompress_addr(struct sk_buff *skb,
		struct in6_addr *ipaddr,
		const u8 address_mode,
		const struct ieee802154_addr *lladdr)
{
	bool fail;

	switch (address_mode) {
	case LOWPAN_IPHC_ADDR_00:
		/* for global link addresses */
		fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
		break;
	case LOWPAN_IPHC_ADDR_01:
		/* fe:80::XXXX:XXXX:XXXX:XXXX */
		ipaddr->s6_addr[0] = 0xFE;
		ipaddr->s6_addr[1] = 0x80;
		fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[8], 8);
		break;
	case LOWPAN_IPHC_ADDR_02:
		/* fe:80::ff:fe00:XXXX */
		ipaddr->s6_addr[0] = 0xFE;
		ipaddr->s6_addr[1] = 0x80;
		ipaddr->s6_addr[11] = 0xFF;
		ipaddr->s6_addr[12] = 0xFE;
		fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[14], 2);
		break;
	case LOWPAN_IPHC_ADDR_03:
		fail = false;
		switch (lladdr->addr_type) {
		case IEEE802154_ADDR_LONG:
			/* fe:80::XXXX:XXXX:XXXX:XXXX
			 *        \_________________/
			 *              hwaddr
			 */
			ipaddr->s6_addr[0] = 0xFE;
			ipaddr->s6_addr[1] = 0x80;
			memcpy(&ipaddr->s6_addr[8], lladdr->hwaddr,
					IEEE802154_ADDR_LEN);
			/* second bit-flip (Universe/Local)
			 * is done according RFC2464
			 */
			ipaddr->s6_addr[8] ^= 0x02;
			break;
		case IEEE802154_ADDR_SHORT:
			/* fe:80::ff:fe00:XXXX
			 *		  \__/
			 *	       short_addr
			 *
			 * Universe/Local bit is zero.
			 */
			ipaddr->s6_addr[0] = 0xFE;
			ipaddr->s6_addr[1] = 0x80;
			ipaddr->s6_addr[11] = 0xFF;
			ipaddr->s6_addr[12] = 0xFE;
			ipaddr->s6_addr16[7] = htons(lladdr->short_addr);
			break;
		default:
			pr_debug("Invalid addr_type set\n");
			return -EINVAL;
		}
		break;
	default:
		pr_debug("Invalid address mode value: 0x%x\n", address_mode);
		return -EINVAL;
	}

	if (fail) {
		pr_debug("Failed to fetch skb data\n");
		return -EIO;
	}

	lowpan_raw_dump_inline(NULL, "Reconstructed ipv6 addr is:\n",
			ipaddr->s6_addr, 16);

	return 0;
}

/* Uncompress address function for source context
 * based address(non-multicast).
 */
static int
lowpan_uncompress_context_based_src_addr(struct sk_buff *skb,
		struct in6_addr *ipaddr,
		const u8 sam)
{
	switch (sam) {
	case LOWPAN_IPHC_ADDR_00:
		/* unspec address ::
		 * Do nothing, address is already ::
		 */
		break;
	case LOWPAN_IPHC_ADDR_01:
		/* TODO */
	case LOWPAN_IPHC_ADDR_02:
		/* TODO */
	case LOWPAN_IPHC_ADDR_03:
		/* TODO */
		netdev_warn(skb->dev, "SAM value 0x%x not supported\n", sam);
		return -EINVAL;
	default:
		pr_debug("Invalid sam value: 0x%x\n", sam);
		return -EINVAL;
	}

	lowpan_raw_dump_inline(NULL,
			"Reconstructed context based ipv6 src addr is:\n",
			ipaddr->s6_addr, 16);

	return 0;
}

/* Uncompress function for multicast destination address,
 * when M bit is set.
 */
static int
lowpan_uncompress_multicast_daddr(struct sk_buff *skb,
		struct in6_addr *ipaddr,
		const u8 dam)
{
	bool fail;

	switch (dam) {
	case LOWPAN_IPHC_DAM_00:
		/* 00:  128 bits.  The full address
		 * is carried in-line.
		 */
		fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
		break;
	case LOWPAN_IPHC_DAM_01:
		/* 01:  48 bits.  The address takes
		 * the form ffXX::00XX:XXXX:XXXX.
		 */
		ipaddr->s6_addr[0] = 0xFF;
		fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);
		fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[11], 5);
		break;
	case LOWPAN_IPHC_DAM_10:
		/* 10:  32 bits.  The address takes
		 * the form ffXX::00XX:XXXX.
		 */
		ipaddr->s6_addr[0] = 0xFF;
		fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);
		fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[13], 3);
		break;
	case LOWPAN_IPHC_DAM_11:
		/* 11:  8 bits.  The address takes
		 * the form ff02::00XX.
		 */
		ipaddr->s6_addr[0] = 0xFF;
		ipaddr->s6_addr[1] = 0x02;
		fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[15], 1);
		break;
	default:
		pr_debug("DAM value has a wrong value: 0x%x\n", dam);
		return -EINVAL;
	}

	if (fail) {
		pr_debug("Failed to fetch skb data\n");
		return -EIO;
	}

	lowpan_raw_dump_inline(NULL, "Reconstructed ipv6 multicast addr is:\n",
			ipaddr->s6_addr, 16);

	return 0;
}

static void
lowpan_compress_udp_header(u8 **hc06_ptr, struct sk_buff *skb)
{
	struct udphdr *uh = udp_hdr(skb);

	if (((uh->source & LOWPAN_NHC_UDP_4BIT_MASK) ==
				LOWPAN_NHC_UDP_4BIT_PORT) &&
	    ((uh->dest & LOWPAN_NHC_UDP_4BIT_MASK) ==
				LOWPAN_NHC_UDP_4BIT_PORT)) {
		pr_debug("UDP header: both ports compression to 4 bits\n");
		**hc06_ptr = LOWPAN_NHC_UDP_CS_P_11;
		**(hc06_ptr + 1) = /* subtraction is faster */
		   (u8)((uh->dest - LOWPAN_NHC_UDP_4BIT_PORT) +
		       ((uh->source & LOWPAN_NHC_UDP_4BIT_PORT) << 4));
		*hc06_ptr += 2;
	} else if ((uh->dest & LOWPAN_NHC_UDP_8BIT_MASK) ==
			LOWPAN_NHC_UDP_8BIT_PORT) {
		pr_debug("UDP header: remove 8 bits of dest\n");
		**hc06_ptr = LOWPAN_NHC_UDP_CS_P_01;
		memcpy(*hc06_ptr + 1, &uh->source, 2);
		**(hc06_ptr + 3) = (u8)(uh->dest - LOWPAN_NHC_UDP_8BIT_PORT);
		*hc06_ptr += 4;
	} else if ((uh->source & LOWPAN_NHC_UDP_8BIT_MASK) ==
			LOWPAN_NHC_UDP_8BIT_PORT) {
		pr_debug("UDP header: remove 8 bits of source\n");
		**hc06_ptr = LOWPAN_NHC_UDP_CS_P_10;
		memcpy(*hc06_ptr + 1, &uh->dest, 2);
		**(hc06_ptr + 3) = (u8)(uh->source - LOWPAN_NHC_UDP_8BIT_PORT);
		*hc06_ptr += 4;
	} else {
		pr_debug("UDP header: can't compress\n");
		**hc06_ptr = LOWPAN_NHC_UDP_CS_P_00;
		memcpy(*hc06_ptr + 1, &uh->source, 2);
		memcpy(*hc06_ptr + 3, &uh->dest, 2);
		*hc06_ptr += 5;
	}

	/* checksum is always inline */
	memcpy(*hc06_ptr, &uh->check, 2);
	*hc06_ptr += 2;

	/* skip the UDP header */
	skb_pull(skb, sizeof(struct udphdr));
}

static inline int lowpan_fetch_skb_u8(struct sk_buff *skb, u8 *val)
{
	if (unlikely(!pskb_may_pull(skb, 1)))
		return -EINVAL;

	*val = skb->data[0];
	skb_pull(skb, 1);

	return 0;
}

static inline int lowpan_fetch_skb_u16(struct sk_buff *skb, u16 *val)
{
	if (unlikely(!pskb_may_pull(skb, 2)))
		return -EINVAL;

	*val = (skb->data[0] << 8) | skb->data[1];
	skb_pull(skb, 2);

	return 0;
}

static int
lowpan_uncompress_udp_header(struct sk_buff *skb, struct udphdr *uh)
{
	u8 tmp;

	if (!uh)
		goto err;

	if (lowpan_fetch_skb_u8(skb, &tmp))
		goto err;

	if ((tmp & LOWPAN_NHC_UDP_MASK) == LOWPAN_NHC_UDP_ID) {
		pr_debug("UDP header uncompression\n");
		switch (tmp & LOWPAN_NHC_UDP_CS_P_11) {
		case LOWPAN_NHC_UDP_CS_P_00:
			memcpy(&uh->source, &skb->data[0], 2);
			memcpy(&uh->dest, &skb->data[2], 2);
			skb_pull(skb, 4);
			break;
		case LOWPAN_NHC_UDP_CS_P_01:
			memcpy(&uh->source, &skb->data[0], 2);
			uh->dest =
			   skb->data[2] + LOWPAN_NHC_UDP_8BIT_PORT;
			skb_pull(skb, 3);
			break;
		case LOWPAN_NHC_UDP_CS_P_10:
			uh->source = skb->data[0] + LOWPAN_NHC_UDP_8BIT_PORT;
			memcpy(&uh->dest, &skb->data[1], 2);
			skb_pull(skb, 3);
			break;
		case LOWPAN_NHC_UDP_CS_P_11:
			uh->source =
			   LOWPAN_NHC_UDP_4BIT_PORT + (skb->data[0] >> 4);
			uh->dest =
			   LOWPAN_NHC_UDP_4BIT_PORT + (skb->data[0] & 0x0f);
			skb_pull(skb, 1);
			break;
		default:
			pr_debug("ERROR: unknown UDP format\n");
			goto err;
		}

		pr_debug("uncompressed UDP ports: src = %d, dst = %d\n",
			 uh->source, uh->dest);

		/* copy checksum */
		memcpy(&uh->check, &skb->data[0], 2);
		skb_pull(skb, 2);

		/*
		 * UDP lenght needs to be infered from the lower layers
		 * here, we obtain the hint from the remaining size of the
		 * frame
		 */
		uh->len = htons(skb->len + sizeof(struct udphdr));
		pr_debug("uncompressed UDP length: src = %d", uh->len);
	} else {
		pr_debug("ERROR: unsupported NH format\n");
		goto err;
	}

	return 0;
err:
	return -EINVAL;
}

static int lowpan_header_create(struct sk_buff *skb,
			   struct net_device *dev,
			   unsigned short type, const void *_daddr,
			   const void *_saddr, unsigned int len)
{
	u8 tmp, iphc0, iphc1, *hc06_ptr;
	struct ipv6hdr *hdr;
	const u8 *saddr = _saddr;
	const u8 *daddr = _daddr;
	u8 head[100];
	struct ieee802154_addr sa, da;

	/* TODO:
	 * if this package isn't ipv6 one, where should it be routed?
	 */
	if (type != ETH_P_IPV6)
		return 0;

	hdr = ipv6_hdr(skb);
	hc06_ptr = head + 2;

	pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength  = %d\n"
		 "\tnexthdr = 0x%02x\n\thop_lim = %d\n", hdr->version,
		 ntohs(hdr->payload_len), hdr->nexthdr, hdr->hop_limit);

	lowpan_raw_dump_table(__func__, "raw skb network header dump",
		skb_network_header(skb), sizeof(struct ipv6hdr));

	if (!saddr)
		saddr = dev->dev_addr;

	lowpan_raw_dump_inline(__func__, "saddr", (unsigned char *)saddr, 8);

	/*
	 * As we copy some bit-length fields, in the IPHC encoding bytes,
	 * we sometimes use |=
	 * If the field is 0, and the current bit value in memory is 1,
	 * this does not work. We therefore reset the IPHC encoding here
	 */
	iphc0 = LOWPAN_DISPATCH_IPHC;
	iphc1 = 0;

	/* TODO: context lookup */

	lowpan_raw_dump_inline(__func__, "daddr", (unsigned char *)daddr, 8);

	/*
	 * Traffic class, flow label
	 * If flow label is 0, compress it. If traffic class is 0, compress it
	 * We have to process both in the same time as the offset of traffic
	 * class depends on the presence of version and flow label
	 */

	/* hc06 format of TC is ECN | DSCP , original one is DSCP | ECN */
	tmp = (hdr->priority << 4) | (hdr->flow_lbl[0] >> 4);
	tmp = ((tmp & 0x03) << 6) | (tmp >> 2);

	if (((hdr->flow_lbl[0] & 0x0F) == 0) &&
	     (hdr->flow_lbl[1] == 0) && (hdr->flow_lbl[2] == 0)) {
		/* flow label can be compressed */
		iphc0 |= LOWPAN_IPHC_FL_C;
		if ((hdr->priority == 0) &&
		   ((hdr->flow_lbl[0] & 0xF0) == 0)) {
			/* compress (elide) all */
			iphc0 |= LOWPAN_IPHC_TC_C;
		} else {
			/* compress only the flow label */
			*hc06_ptr = tmp;
			hc06_ptr += 1;
		}
	} else {
		/* Flow label cannot be compressed */
		if ((hdr->priority == 0) &&
		   ((hdr->flow_lbl[0] & 0xF0) == 0)) {
			/* compress only traffic class */
			iphc0 |= LOWPAN_IPHC_TC_C;
			*hc06_ptr = (tmp & 0xc0) | (hdr->flow_lbl[0] & 0x0F);
			memcpy(hc06_ptr + 1, &hdr->flow_lbl[1], 2);
			hc06_ptr += 3;
		} else {
			/* compress nothing */
			memcpy(hc06_ptr, &hdr, 4);
			/* replace the top byte with new ECN | DSCP format */
			*hc06_ptr = tmp;
			hc06_ptr += 4;
		}
	}

	/* NOTE: payload length is always compressed */

	/* Next Header is compress if UDP */
	if (hdr->nexthdr == UIP_PROTO_UDP)
		iphc0 |= LOWPAN_IPHC_NH_C;

	if ((iphc0 & LOWPAN_IPHC_NH_C) == 0) {
		*hc06_ptr = hdr->nexthdr;
		hc06_ptr += 1;
	}

	/*
	 * Hop limit
	 * if 1:   compress, encoding is 01
	 * if 64:  compress, encoding is 10
	 * if 255: compress, encoding is 11
	 * else do not compress
	 */
	switch (hdr->hop_limit) {
	case 1:
		iphc0 |= LOWPAN_IPHC_TTL_1;
		break;
	case 64:
		iphc0 |= LOWPAN_IPHC_TTL_64;
		break;
	case 255:
		iphc0 |= LOWPAN_IPHC_TTL_255;
		break;
	default:
		*hc06_ptr = hdr->hop_limit;
		hc06_ptr += 1;
		break;
	}

	/* source address compression */
	if (is_addr_unspecified(&hdr->saddr)) {
		pr_debug("source address is unspecified, setting SAC\n");
		iphc1 |= LOWPAN_IPHC_SAC;
	/* TODO: context lookup */
	} else if (is_addr_link_local(&hdr->saddr)) {
		pr_debug("source address is link-local\n");
		iphc1 |= lowpan_compress_addr_64(&hc06_ptr,
				LOWPAN_IPHC_SAM_BIT, &hdr->saddr, saddr);
	} else {
		pr_debug("send the full source address\n");
		memcpy(hc06_ptr, &hdr->saddr.s6_addr16[0], 16);
		hc06_ptr += 16;
	}

	/* destination address compression */
	if (is_addr_mcast(&hdr->daddr)) {
		pr_debug("destination address is multicast: ");
		iphc1 |= LOWPAN_IPHC_M;
		if (lowpan_is_mcast_addr_compressable8(&hdr->daddr)) {
			pr_debug("compressed to 1 octet\n");
			iphc1 |= LOWPAN_IPHC_DAM_11;
			/* use last byte */
			*hc06_ptr = hdr->daddr.s6_addr[15];
			hc06_ptr += 1;
		} else if (lowpan_is_mcast_addr_compressable32(&hdr->daddr)) {
			pr_debug("compressed to 4 octets\n");
			iphc1 |= LOWPAN_IPHC_DAM_10;
			/* second byte + the last three */
			*hc06_ptr = hdr->daddr.s6_addr[1];
			memcpy(hc06_ptr + 1, &hdr->daddr.s6_addr[13], 3);
			hc06_ptr += 4;
		} else if (lowpan_is_mcast_addr_compressable48(&hdr->daddr)) {
			pr_debug("compressed to 6 octets\n");
			iphc1 |= LOWPAN_IPHC_DAM_01;
			/* second byte + the last five */
			*hc06_ptr = hdr->daddr.s6_addr[1];
			memcpy(hc06_ptr + 1, &hdr->daddr.s6_addr[11], 5);
			hc06_ptr += 6;
		} else {
			pr_debug("using full address\n");
			iphc1 |= LOWPAN_IPHC_DAM_00;
			memcpy(hc06_ptr, &hdr->daddr.s6_addr[0], 16);
			hc06_ptr += 16;
		}
	} else {
		/* TODO: context lookup */
		if (is_addr_link_local(&hdr->daddr)) {
			pr_debug("dest address is unicast and link-local\n");
			iphc1 |= lowpan_compress_addr_64(&hc06_ptr,
				LOWPAN_IPHC_DAM_BIT, &hdr->daddr, daddr);
		} else {
			pr_debug("dest address is unicast: using full one\n");
			memcpy(hc06_ptr, &hdr->daddr.s6_addr16[0], 16);
			hc06_ptr += 16;
		}
	}

	/* UDP header compression */
	if (hdr->nexthdr == UIP_PROTO_UDP)
		lowpan_compress_udp_header(&hc06_ptr, skb);

	head[0] = iphc0;
	head[1] = iphc1;

	skb_pull(skb, sizeof(struct ipv6hdr));
	skb_reset_transport_header(skb);
	memcpy(skb_push(skb, hc06_ptr - head), head, hc06_ptr - head);
	skb_reset_network_header(skb);

	lowpan_raw_dump_table(__func__, "raw skb data dump", skb->data,
				skb->len);

	/*
	 * NOTE1: I'm still unsure about the fact that compression and WPAN
	 * header are created here and not later in the xmit. So wait for
	 * an opinion of net maintainers.
	 */
	/*
	 * NOTE2: to be absolutely correct, we must derive PANid information
	 * from MAC subif of the 'dev' and 'real_dev' network devices, but
	 * this isn't implemented in mainline yet, so currently we assign 0xff
	 */
	{
		mac_cb(skb)->flags = IEEE802154_FC_TYPE_DATA;
		mac_cb(skb)->seq = ieee802154_mlme_ops(dev)->get_dsn(dev);

		/* prepare wpan address data */
		sa.addr_type = IEEE802154_ADDR_LONG;
		sa.pan_id = ieee802154_mlme_ops(dev)->get_pan_id(dev);

		memcpy(&(sa.hwaddr), saddr, 8);
		/* intra-PAN communications */
		da.pan_id = ieee802154_mlme_ops(dev)->get_pan_id(dev);

		/*
		 * if the destination address is the broadcast address, use the
		 * corresponding short address
		 */
		if (lowpan_is_addr_broadcast(daddr)) {
			da.addr_type = IEEE802154_ADDR_SHORT;
			da.short_addr = IEEE802154_ADDR_BROADCAST;
		} else {
			da.addr_type = IEEE802154_ADDR_LONG;
			memcpy(&(da.hwaddr), daddr, IEEE802154_ADDR_LEN);

			/* request acknowledgment */
			mac_cb(skb)->flags |= MAC_CB_FLAG_ACKREQ;
		}

		return dev_hard_header(skb, lowpan_dev_info(dev)->real_dev,
				type, (void *)&da, (void *)&sa, skb->len);
	}
}

static int lowpan_give_skb_to_devices(struct sk_buff *skb)
{
	struct lowpan_dev_record *entry;
	struct sk_buff *skb_cp;
	int stat = NET_RX_SUCCESS;

	rcu_read_lock();
	list_for_each_entry_rcu(entry, &lowpan_devices, list)
		if (lowpan_dev_info(entry->ldev)->real_dev == skb->dev) {
			skb_cp = skb_copy(skb, GFP_ATOMIC);
			if (!skb_cp) {
				stat = -ENOMEM;
				break;
			}

			skb_cp->dev = entry->ldev;
			stat = netif_rx(skb_cp);
		}
	rcu_read_unlock();

	return stat;
}

static int lowpan_skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr)
{
	struct sk_buff *new;
	int stat = NET_RX_SUCCESS;

	new = skb_copy_expand(skb, sizeof(struct ipv6hdr), skb_tailroom(skb),
								GFP_ATOMIC);
	kfree_skb(skb);

	if (!new)
		return -ENOMEM;

	skb_push(new, sizeof(struct ipv6hdr));
	skb_copy_to_linear_data(new, hdr, sizeof(struct ipv6hdr));

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

	stat = lowpan_give_skb_to_devices(new);

	kfree_skb(new);

	return stat;
}

static void lowpan_fragment_timer_expired(unsigned long entry_addr)
{
	struct lowpan_fragment *entry = (struct lowpan_fragment *)entry_addr;

	pr_debug("timer expired for frame with tag %d\n", entry->tag);

	list_del(&entry->list);
	dev_kfree_skb(entry->skb);
	kfree(entry);
}

static struct lowpan_fragment *
lowpan_alloc_new_frame(struct sk_buff *skb, u16 len, u16 tag)
{
	struct lowpan_fragment *frame;

	frame = kzalloc(sizeof(struct lowpan_fragment),
			GFP_ATOMIC);
	if (!frame)
		goto frame_err;

	INIT_LIST_HEAD(&frame->list);

	frame->length = len;
	frame->tag = tag;

	/* allocate buffer for frame assembling */
	frame->skb = netdev_alloc_skb_ip_align(skb->dev, frame->length +
					       sizeof(struct ipv6hdr));

	if (!frame->skb)
		goto skb_err;

	frame->skb->priority = skb->priority;

	/* reserve headroom for uncompressed ipv6 header */
	skb_reserve(frame->skb, sizeof(struct ipv6hdr));
	skb_put(frame->skb, frame->length);

	/* copy the first control block to keep a
	 * trace of the link-layer addresses in case
	 * of a link-local compressed address
	 */
	memcpy(frame->skb->cb, skb->cb, sizeof(skb->cb));

	init_timer(&frame->timer);
	/* time out is the same as for ipv6 - 60 sec */
	frame->timer.expires = jiffies + LOWPAN_FRAG_TIMEOUT;
	frame->timer.data = (unsigned long)frame;
	frame->timer.function = lowpan_fragment_timer_expired;

	add_timer(&frame->timer);

	list_add_tail(&frame->list, &lowpan_fragments);

	return frame;

skb_err:
	kfree(frame);
frame_err:
	return NULL;
}

static int
lowpan_process_data(struct sk_buff *skb)
{
	struct ipv6hdr hdr = {};
	u8 tmp, iphc0, iphc1, num_context = 0;
	const struct ieee802154_addr *_saddr, *_daddr;
	int err;

	lowpan_raw_dump_table(__func__, "raw skb data dump", skb->data,
				skb->len);
	/* at least two bytes will be used for the encoding */
	if (skb->len < 2)
		goto drop;

	if (lowpan_fetch_skb_u8(skb, &iphc0))
		goto drop;

	/* fragments assembling */
	switch (iphc0 & LOWPAN_DISPATCH_MASK) {
	case LOWPAN_DISPATCH_FRAG1:
	case LOWPAN_DISPATCH_FRAGN:
	{
		struct lowpan_fragment *frame;
		/* slen stores the rightmost 8 bits of the 11 bits length */
		u8 slen, offset = 0;
		u16 len, tag;
		bool found = false;

		if (lowpan_fetch_skb_u8(skb, &slen) || /* frame length */
		    lowpan_fetch_skb_u16(skb, &tag))  /* fragment tag */
			goto drop;

		/* adds the 3 MSB to the 8 LSB to retrieve the 11 bits length */
		len = ((iphc0 & 7) << 8) | slen;

		if ((iphc0 & LOWPAN_DISPATCH_MASK) == LOWPAN_DISPATCH_FRAG1) {
			pr_debug("%s received a FRAG1 packet (tag: %d, "
				 "size of the entire IP packet: %d)",
				 __func__, tag, len);
		} else { /* FRAGN */
			if (lowpan_fetch_skb_u8(skb, &offset))
				goto unlock_and_drop;
			pr_debug("%s received a FRAGN packet (tag: %d, "
				 "size of the entire IP packet: %d, "
				 "offset: %d)", __func__, tag, len, offset * 8);
		}

		/*
		 * check if frame assembling with the same tag is
		 * already in progress
		 */
		spin_lock_bh(&flist_lock);

		list_for_each_entry(frame, &lowpan_fragments, list)
			if (frame->tag == tag) {
				found = true;
				break;
			}

		/* alloc new frame structure */
		if (!found) {
			pr_debug("%s first fragment received for tag %d, "
				 "begin packet reassembly", __func__, tag);
			frame = lowpan_alloc_new_frame(skb, len, tag);
			if (!frame)
				goto unlock_and_drop;
		}

		/* if payload fits buffer, copy it */
		if (likely((offset * 8 + skb->len) <= frame->length))
			skb_copy_to_linear_data_offset(frame->skb, offset * 8,
							skb->data, skb->len);
		else
			goto unlock_and_drop;

		frame->bytes_rcv += skb->len;

		/* frame assembling complete */
		if ((frame->bytes_rcv == frame->length) &&
		     frame->timer.expires > jiffies) {
			/* if timer haven't expired - first of all delete it */
			del_timer_sync(&frame->timer);
			list_del(&frame->list);
			spin_unlock_bh(&flist_lock);

			pr_debug("%s successfully reassembled fragment "
				 "(tag %d)", __func__, tag);

			dev_kfree_skb(skb);
			skb = frame->skb;
			kfree(frame);

			if (lowpan_fetch_skb_u8(skb, &iphc0))
				goto drop;

			break;
		}
		spin_unlock_bh(&flist_lock);

		return kfree_skb(skb), 0;
	}
	default:
		break;
	}

	if (lowpan_fetch_skb_u8(skb, &iphc1))
		goto drop;

	_saddr = &mac_cb(skb)->sa;
	_daddr = &mac_cb(skb)->da;

	pr_debug("iphc0 = %02x, iphc1 = %02x\n", iphc0, iphc1);

	/* another if the CID flag is set */
	if (iphc1 & LOWPAN_IPHC_CID) {
		pr_debug("CID flag is set, increase header with one\n");
		if (lowpan_fetch_skb_u8(skb, &num_context))
			goto drop;
	}

	hdr.version = 6;

	/* Traffic Class and Flow Label */
	switch ((iphc0 & LOWPAN_IPHC_TF) >> 3) {
	/*
	 * Traffic Class and FLow Label carried in-line
	 * ECN + DSCP + 4-bit Pad + Flow Label (4 bytes)
	 */
	case 0: /* 00b */
		if (lowpan_fetch_skb_u8(skb, &tmp))
			goto drop;

		memcpy(&hdr.flow_lbl, &skb->data[0], 3);
		skb_pull(skb, 3);
		hdr.priority = ((tmp >> 2) & 0x0f);
		hdr.flow_lbl[0] = ((tmp >> 2) & 0x30) | (tmp << 6) |
					(hdr.flow_lbl[0] & 0x0f);
		break;
	/*
	 * Traffic class carried in-line
	 * ECN + DSCP (1 byte), Flow Label is elided
	 */
	case 2: /* 10b */
		if (lowpan_fetch_skb_u8(skb, &tmp))
			goto drop;

		hdr.priority = ((tmp >> 2) & 0x0f);
		hdr.flow_lbl[0] = ((tmp << 6) & 0xC0) | ((tmp >> 2) & 0x30);
		break;
	/*
	 * Flow Label carried in-line
	 * ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided
	 */
	case 1: /* 01b */
		if (lowpan_fetch_skb_u8(skb, &tmp))
			goto drop;

		hdr.flow_lbl[0] = (skb->data[0] & 0x0F) | ((tmp >> 2) & 0x30);
		memcpy(&hdr.flow_lbl[1], &skb->data[0], 2);
		skb_pull(skb, 2);
		break;
	/* Traffic Class and Flow Label are elided */
	case 3: /* 11b */
		break;
	default:
		break;
	}

	/* Next Header */
	if ((iphc0 & LOWPAN_IPHC_NH_C) == 0) {
		/* Next header is carried inline */
		if (lowpan_fetch_skb_u8(skb, &(hdr.nexthdr)))
			goto drop;

		pr_debug("NH flag is set, next header carried inline: %02x\n",
			 hdr.nexthdr);
	}

	/* Hop Limit */
	if ((iphc0 & 0x03) != LOWPAN_IPHC_TTL_I)
		hdr.hop_limit = lowpan_ttl_values[iphc0 & 0x03];
	else {
		if (lowpan_fetch_skb_u8(skb, &(hdr.hop_limit)))
			goto drop;
	}

	/* Extract SAM to the tmp variable */
	tmp = ((iphc1 & LOWPAN_IPHC_SAM) >> LOWPAN_IPHC_SAM_BIT) & 0x03;

	if (iphc1 & LOWPAN_IPHC_SAC) {
		/* Source address context based uncompression */
		pr_debug("SAC bit is set. Handle context based source address.\n");
		err = lowpan_uncompress_context_based_src_addr(
				skb, &hdr.saddr, tmp);
	} else {
		/* Source address uncompression */
		pr_debug("source address stateless compression\n");
		err = lowpan_uncompress_addr(skb, &hdr.saddr, tmp, _saddr);
	}

	/* Check on error of previous branch */
	if (err)
		goto drop;

	/* Extract DAM to the tmp variable */
	tmp = ((iphc1 & LOWPAN_IPHC_DAM_11) >> LOWPAN_IPHC_DAM_BIT) & 0x03;

	/* check for Multicast Compression */
	if (iphc1 & LOWPAN_IPHC_M) {
		if (iphc1 & LOWPAN_IPHC_DAC) {
			pr_debug("dest: context-based mcast compression\n");
			/* TODO: implement this */
		} else {
			err = lowpan_uncompress_multicast_daddr(
					skb, &hdr.daddr, tmp);
			if (err)
				goto drop;
		}
	} else {
		pr_debug("dest: stateless compression\n");
		err = lowpan_uncompress_addr(skb, &hdr.daddr, tmp, _daddr);
		if (err)
			goto drop;
	}

	/* UDP data uncompression */
	if (iphc0 & LOWPAN_IPHC_NH_C) {
		struct udphdr uh;
		struct sk_buff *new;
		if (lowpan_uncompress_udp_header(skb, &uh))
			goto drop;

		/*
		 * replace the compressed UDP head by the uncompressed UDP
		 * header
		 */
		new = skb_copy_expand(skb, sizeof(struct udphdr),
				      skb_tailroom(skb), GFP_ATOMIC);
		kfree_skb(skb);

		if (!new)
			return -ENOMEM;

		skb = new;

		skb_push(skb, sizeof(struct udphdr));
		skb_copy_to_linear_data(skb, &uh, sizeof(struct udphdr));

		lowpan_raw_dump_table(__func__, "raw UDP header dump",
				      (u8 *)&uh, sizeof(uh));

		hdr.nexthdr = UIP_PROTO_UDP;
	}

	/* Not fragmented package */
	hdr.payload_len = htons(skb->len);

	pr_debug("skb headroom size = %d, data length = %d\n",
		 skb_headroom(skb), skb->len);

	pr_debug("IPv6 header dump:\n\tversion = %d\n\tlength  = %d\n\t"
		 "nexthdr = 0x%02x\n\thop_lim = %d\n", hdr.version,
		 ntohs(hdr.payload_len), hdr.nexthdr, hdr.hop_limit);

	lowpan_raw_dump_table(__func__, "raw header dump", (u8 *)&hdr,
							sizeof(hdr));
	return lowpan_skb_deliver(skb, &hdr);

unlock_and_drop:
	spin_unlock_bh(&flist_lock);
drop:
	kfree_skb(skb);
	return -EINVAL;
}

static int lowpan_set_address(struct net_device *dev, void *p)
{
	struct sockaddr *sa = p;

	if (netif_running(dev))
		return -EBUSY;

	/* TODO: validate addr */
	memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);

	return 0;
}

static int
lowpan_fragment_xmit(struct sk_buff *skb, u8 *head,
			int mlen, int plen, int offset, int type)
{
	struct sk_buff *frag;
	int hlen;

	hlen = (type == LOWPAN_DISPATCH_FRAG1) ?
			LOWPAN_FRAG1_HEAD_SIZE : LOWPAN_FRAGN_HEAD_SIZE;

	lowpan_raw_dump_inline(__func__, "6lowpan fragment header", head, hlen);

	frag = netdev_alloc_skb(skb->dev,
				hlen + mlen + plen + IEEE802154_MFR_SIZE);
	if (!frag)
		return -ENOMEM;

	frag->priority = skb->priority;

	/* copy header, MFR and payload */
	skb_put(frag, mlen);
	skb_copy_to_linear_data(frag, skb_mac_header(skb), mlen);

	skb_put(frag, hlen);
	skb_copy_to_linear_data_offset(frag, mlen, head, hlen);

	skb_put(frag, plen);
	skb_copy_to_linear_data_offset(frag, mlen + hlen,
				       skb_network_header(skb) + offset, plen);

	lowpan_raw_dump_table(__func__, " raw fragment dump", frag->data,
								frag->len);

	return dev_queue_xmit(frag);
}

static int
lowpan_skb_fragmentation(struct sk_buff *skb, struct net_device *dev)
{
	int  err, header_length, payload_length, tag, offset = 0;
	u8 head[5];

	header_length = skb->mac_len;
	payload_length = skb->len - header_length;
	tag = lowpan_dev_info(dev)->fragment_tag++;

	/* first fragment header */
	head[0] = LOWPAN_DISPATCH_FRAG1 | ((payload_length >> 8) & 0x7);
	head[1] = payload_length & 0xff;
	head[2] = tag >> 8;
	head[3] = tag & 0xff;

	err = lowpan_fragment_xmit(skb, head, header_length, LOWPAN_FRAG_SIZE,
				   0, LOWPAN_DISPATCH_FRAG1);

	if (err) {
		pr_debug("%s unable to send FRAG1 packet (tag: %d)",
			 __func__, tag);
		goto exit;
	}

	offset = LOWPAN_FRAG_SIZE;

	/* next fragment header */
	head[0] &= ~LOWPAN_DISPATCH_FRAG1;
	head[0] |= LOWPAN_DISPATCH_FRAGN;

	while (payload_length - offset > 0) {
		int len = LOWPAN_FRAG_SIZE;

		head[4] = offset / 8;

		if (payload_length - offset < len)
			len = payload_length - offset;

		err = lowpan_fragment_xmit(skb, head, header_length,
					   len, offset, LOWPAN_DISPATCH_FRAGN);
		if (err) {
			pr_debug("%s unable to send a subsequent FRAGN packet "
				 "(tag: %d, offset: %d", __func__, tag, offset);
			goto exit;
		}

		offset += len;
	}

exit:
	return err;
}

static netdev_tx_t lowpan_xmit(struct sk_buff *skb, struct net_device *dev)
{
	int err = -1;

	pr_debug("package xmit\n");

	skb->dev = lowpan_dev_info(dev)->real_dev;
	if (skb->dev == NULL) {
		pr_debug("ERROR: no real wpan device found\n");
		goto error;
	}

	/* Send directly if less than the MTU minus the 2 checksum bytes. */
	if (skb->len <= IEEE802154_MTU - IEEE802154_MFR_SIZE) {
		err = dev_queue_xmit(skb);
		goto out;
	}

	pr_debug("frame is too big, fragmentation is needed\n");
	err = lowpan_skb_fragmentation(skb, dev);
error:
	dev_kfree_skb(skb);
out:
	if (err)
		pr_debug("ERROR: xmit failed\n");

	return (err < 0) ? NET_XMIT_DROP : err;
}

static struct wpan_phy *lowpan_get_phy(const struct net_device *dev)
{
	struct net_device *real_dev = lowpan_dev_info(dev)->real_dev;
	return ieee802154_mlme_ops(real_dev)->get_phy(real_dev);
}

static u16 lowpan_get_pan_id(const struct net_device *dev)
{
	struct net_device *real_dev = lowpan_dev_info(dev)->real_dev;
	return ieee802154_mlme_ops(real_dev)->get_pan_id(real_dev);
}

static u16 lowpan_get_short_addr(const struct net_device *dev)
{
	struct net_device *real_dev = lowpan_dev_info(dev)->real_dev;
	return ieee802154_mlme_ops(real_dev)->get_short_addr(real_dev);
}

static u8 lowpan_get_dsn(const struct net_device *dev)
{
	struct net_device *real_dev = lowpan_dev_info(dev)->real_dev;
	return ieee802154_mlme_ops(real_dev)->get_dsn(real_dev);
}

static struct header_ops lowpan_header_ops = {
	.create	= lowpan_header_create,
};

static const struct net_device_ops lowpan_netdev_ops = {
	.ndo_start_xmit		= lowpan_xmit,
	.ndo_set_mac_address	= lowpan_set_address,
};

static struct ieee802154_mlme_ops lowpan_mlme = {
	.get_pan_id = lowpan_get_pan_id,
	.get_phy = lowpan_get_phy,
	.get_short_addr = lowpan_get_short_addr,
	.get_dsn = lowpan_get_dsn,
};

static void lowpan_setup(struct net_device *dev)
{
	dev->addr_len		= IEEE802154_ADDR_LEN;
	memset(dev->broadcast, 0xff, IEEE802154_ADDR_LEN);
	dev->type		= ARPHRD_IEEE802154;
	/* Frame Control + Sequence Number + Address fields + Security Header */
	dev->hard_header_len	= 2 + 1 + 20 + 14;
	dev->needed_tailroom	= 2; /* FCS */
	dev->mtu		= 1281;
	dev->tx_queue_len	= 0;
	dev->flags		= IFF_BROADCAST | IFF_MULTICAST;
	dev->watchdog_timeo	= 0;

	dev->netdev_ops		= &lowpan_netdev_ops;
	dev->header_ops		= &lowpan_header_ops;
	dev->ml_priv		= &lowpan_mlme;
	dev->destructor		= free_netdev;
}

static int lowpan_validate(struct nlattr *tb[], struct nlattr *data[])
{
	if (tb[IFLA_ADDRESS]) {
		if (nla_len(tb[IFLA_ADDRESS]) != IEEE802154_ADDR_LEN)
			return -EINVAL;
	}
	return 0;
}

static int lowpan_rcv(struct sk_buff *skb, struct net_device *dev,
	struct packet_type *pt, struct net_device *orig_dev)
{
	struct sk_buff *local_skb;

	if (!netif_running(dev))
		goto drop;

	if (dev->type != ARPHRD_IEEE802154)
		goto drop;

	/* check that it's our buffer */
	if (skb->data[0] == LOWPAN_DISPATCH_IPV6) {
		/* 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;

		/* Pull off the 1-byte of 6lowpan header. */
		skb_pull(local_skb, 1);

		lowpan_give_skb_to_devices(local_skb);

		kfree_skb(local_skb);
		kfree_skb(skb);
	} else {
		switch (skb->data[0] & 0xe0) {
		case LOWPAN_DISPATCH_IPHC:	/* ipv6 datagram */
		case LOWPAN_DISPATCH_FRAG1:	/* first fragment header */
		case LOWPAN_DISPATCH_FRAGN:	/* next fragments headers */
			local_skb = skb_clone(skb, GFP_ATOMIC);
			if (!local_skb)
				goto drop;
			lowpan_process_data(local_skb);

			kfree_skb(skb);
			break;
		default:
			break;
		}
	}

	return NET_RX_SUCCESS;

drop:
	kfree_skb(skb);
	return NET_RX_DROP;
}

static int lowpan_newlink(struct net *src_net, struct net_device *dev,
			  struct nlattr *tb[], struct nlattr *data[])
{
	struct net_device *real_dev;
	struct lowpan_dev_record *entry;

	pr_debug("adding new link\n");

	if (!tb[IFLA_LINK])
		return -EINVAL;
	/* find and hold real wpan device */
	real_dev = dev_get_by_index(src_net, nla_get_u32(tb[IFLA_LINK]));
	if (!real_dev)
		return -ENODEV;
	if (real_dev->type != ARPHRD_IEEE802154) {
		dev_put(real_dev);
		return -EINVAL;
	}

	lowpan_dev_info(dev)->real_dev = real_dev;
	lowpan_dev_info(dev)->fragment_tag = 0;
	mutex_init(&lowpan_dev_info(dev)->dev_list_mtx);

	entry = kzalloc(sizeof(struct lowpan_dev_record), GFP_KERNEL);
	if (!entry) {
		dev_put(real_dev);
		lowpan_dev_info(dev)->real_dev = NULL;
		return -ENOMEM;
	}

	entry->ldev = dev;

	/* Set the lowpan harware address to the wpan hardware address. */
	memcpy(dev->dev_addr, real_dev->dev_addr, IEEE802154_ADDR_LEN);

	mutex_lock(&lowpan_dev_info(dev)->dev_list_mtx);
	INIT_LIST_HEAD(&entry->list);
	list_add_tail(&entry->list, &lowpan_devices);
	mutex_unlock(&lowpan_dev_info(dev)->dev_list_mtx);

	register_netdevice(dev);

	return 0;
}

static void lowpan_dellink(struct net_device *dev, struct list_head *head)
{
	struct lowpan_dev_info *lowpan_dev = lowpan_dev_info(dev);
	struct net_device *real_dev = lowpan_dev->real_dev;
	struct lowpan_dev_record *entry, *tmp;

	ASSERT_RTNL();

	mutex_lock(&lowpan_dev_info(dev)->dev_list_mtx);
	list_for_each_entry_safe(entry, tmp, &lowpan_devices, list) {
		if (entry->ldev == dev) {
			list_del(&entry->list);
			kfree(entry);
		}
	}
	mutex_unlock(&lowpan_dev_info(dev)->dev_list_mtx);

	mutex_destroy(&lowpan_dev_info(dev)->dev_list_mtx);

	unregister_netdevice_queue(dev, head);

	dev_put(real_dev);
}

static struct rtnl_link_ops lowpan_link_ops __read_mostly = {
	.kind		= "lowpan",
	.priv_size	= sizeof(struct lowpan_dev_info),
	.setup		= lowpan_setup,
	.newlink	= lowpan_newlink,
	.dellink	= lowpan_dellink,
	.validate	= lowpan_validate,
};

static inline int __init lowpan_netlink_init(void)
{
	return rtnl_link_register(&lowpan_link_ops);
}

static inline void lowpan_netlink_fini(void)
{
	rtnl_link_unregister(&lowpan_link_ops);
}

static int lowpan_device_event(struct notifier_block *unused,
			       unsigned long event, void *ptr)
{
	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
	LIST_HEAD(del_list);
	struct lowpan_dev_record *entry, *tmp;

	if (dev->type != ARPHRD_IEEE802154)
		goto out;

	if (event == NETDEV_UNREGISTER) {
		list_for_each_entry_safe(entry, tmp, &lowpan_devices, list) {
			if (lowpan_dev_info(entry->ldev)->real_dev == dev)
				lowpan_dellink(entry->ldev, &del_list);
		}

		unregister_netdevice_many(&del_list);
	}

out:
	return NOTIFY_DONE;
}

static struct notifier_block lowpan_dev_notifier = {
	.notifier_call = lowpan_device_event,
};

static struct packet_type lowpan_packet_type = {
	.type = __constant_htons(ETH_P_IEEE802154),
	.func = lowpan_rcv,
};

static int __init lowpan_init_module(void)
{
	int err = 0;

	err = lowpan_netlink_init();
	if (err < 0)
		goto out;

	dev_add_pack(&lowpan_packet_type);

	err = register_netdevice_notifier(&lowpan_dev_notifier);
	if (err < 0) {
		dev_remove_pack(&lowpan_packet_type);
		lowpan_netlink_fini();
	}
out:
	return err;
}

static void __exit lowpan_cleanup_module(void)
{
	struct lowpan_fragment *frame, *tframe;

	lowpan_netlink_fini();

	dev_remove_pack(&lowpan_packet_type);

	unregister_netdevice_notifier(&lowpan_dev_notifier);

	/* Now 6lowpan packet_type is removed, so no new fragments are
	 * expected on RX, therefore that's the time to clean incomplete
	 * fragments.
	 */
	spin_lock_bh(&flist_lock);
	list_for_each_entry_safe(frame, tframe, &lowpan_fragments, list) {
		del_timer_sync(&frame->timer);
		list_del(&frame->list);
		dev_kfree_skb(frame->skb);
		kfree(frame);
	}
	spin_unlock_bh(&flist_lock);
}

module_init(lowpan_init_module);
module_exit(lowpan_cleanup_module);
MODULE_LICENSE("GPL");
MODULE_ALIAS_RTNL_LINK("lowpan");