summaryrefslogtreecommitdiffstats
path: root/include/net/netlink.h
blob: 6bfa972f2fbf251cbc570d5cfe64414f70d9f5d1 (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
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __NET_NETLINK_H
#define __NET_NETLINK_H

#include <linux/types.h>
#include <linux/netlink.h>
#include <linux/jiffies.h>
#include <linux/in6.h>

/* ========================================================================
 *         Netlink Messages and Attributes Interface (As Seen On TV)
 * ------------------------------------------------------------------------
 *                          Messages Interface
 * ------------------------------------------------------------------------
 *
 * Message Format:
 *    <--- nlmsg_total_size(payload)  --->
 *    <-- nlmsg_msg_size(payload) ->
 *   +----------+- - -+-------------+- - -+-------- - -
 *   | nlmsghdr | Pad |   Payload   | Pad | nlmsghdr
 *   +----------+- - -+-------------+- - -+-------- - -
 *   nlmsg_data(nlh)---^                   ^
 *   nlmsg_next(nlh)-----------------------+
 *
 * Payload Format:
 *    <---------------------- nlmsg_len(nlh) --------------------->
 *    <------ hdrlen ------>       <- nlmsg_attrlen(nlh, hdrlen) ->
 *   +----------------------+- - -+--------------------------------+
 *   |     Family Header    | Pad |           Attributes           |
 *   +----------------------+- - -+--------------------------------+
 *   nlmsg_attrdata(nlh, hdrlen)---^
 *
 * Data Structures:
 *   struct nlmsghdr			netlink message header
 *
 * Message Construction:
 *   nlmsg_new()			create a new netlink message
 *   nlmsg_put()			add a netlink message to an skb
 *   nlmsg_put_answer()			callback based nlmsg_put()
 *   nlmsg_end()			finalize netlink message
 *   nlmsg_get_pos()			return current position in message
 *   nlmsg_trim()			trim part of message
 *   nlmsg_cancel()			cancel message construction
 *   nlmsg_free()			free a netlink message
 *
 * Message Sending:
 *   nlmsg_multicast()			multicast message to several groups
 *   nlmsg_unicast()			unicast a message to a single socket
 *   nlmsg_notify()			send notification message
 *
 * Message Length Calculations:
 *   nlmsg_msg_size(payload)		length of message w/o padding
 *   nlmsg_total_size(payload)		length of message w/ padding
 *   nlmsg_padlen(payload)		length of padding at tail
 *
 * Message Payload Access:
 *   nlmsg_data(nlh)			head of message payload
 *   nlmsg_len(nlh)			length of message payload
 *   nlmsg_attrdata(nlh, hdrlen)	head of attributes data
 *   nlmsg_attrlen(nlh, hdrlen)		length of attributes data
 *
 * Message Parsing:
 *   nlmsg_ok(nlh, remaining)		does nlh fit into remaining bytes?
 *   nlmsg_next(nlh, remaining)		get next netlink message
 *   nlmsg_parse()			parse attributes of a message
 *   nlmsg_find_attr()			find an attribute in a message
 *   nlmsg_for_each_msg()		loop over all messages
 *   nlmsg_validate()			validate netlink message incl. attrs
 *   nlmsg_for_each_attr()		loop over all attributes
 *
 * Misc:
 *   nlmsg_report()			report back to application?
 *
 * ------------------------------------------------------------------------
 *                          Attributes Interface
 * ------------------------------------------------------------------------
 *
 * Attribute Format:
 *    <------- nla_total_size(payload) ------->
 *    <---- nla_attr_size(payload) ----->
 *   +----------+- - -+- - - - - - - - - +- - -+-------- - -
 *   |  Header  | Pad |     Payload      | Pad |  Header
 *   +----------+- - -+- - - - - - - - - +- - -+-------- - -
 *                     <- nla_len(nla) ->      ^
 *   nla_data(nla)----^                        |
 *   nla_next(nla)-----------------------------'
 *
 * Data Structures:
 *   struct nlattr			netlink attribute header
 *
 * Attribute Construction:
 *   nla_reserve(skb, type, len)	reserve room for an attribute
 *   nla_reserve_nohdr(skb, len)	reserve room for an attribute w/o hdr
 *   nla_put(skb, type, len, data)	add attribute to skb
 *   nla_put_nohdr(skb, len, data)	add attribute w/o hdr
 *   nla_append(skb, len, data)		append data to skb
 *
 * Attribute Construction for Basic Types:
 *   nla_put_u8(skb, type, value)	add u8 attribute to skb
 *   nla_put_u16(skb, type, value)	add u16 attribute to skb
 *   nla_put_u32(skb, type, value)	add u32 attribute to skb
 *   nla_put_u64_64bit(skb, type,
 *                     value, padattr)	add u64 attribute to skb
 *   nla_put_s8(skb, type, value)	add s8 attribute to skb
 *   nla_put_s16(skb, type, value)	add s16 attribute to skb
 *   nla_put_s32(skb, type, value)	add s32 attribute to skb
 *   nla_put_s64(skb, type, value,
 *               padattr)		add s64 attribute to skb
 *   nla_put_string(skb, type, str)	add string attribute to skb
 *   nla_put_flag(skb, type)		add flag attribute to skb
 *   nla_put_msecs(skb, type, jiffies,
 *                 padattr)		add msecs attribute to skb
 *   nla_put_in_addr(skb, type, addr)	add IPv4 address attribute to skb
 *   nla_put_in6_addr(skb, type, addr)	add IPv6 address attribute to skb
 *
 * Nested Attributes Construction:
 *   nla_nest_start(skb, type)		start a nested attribute
 *   nla_nest_end(skb, nla)		finalize a nested attribute
 *   nla_nest_cancel(skb, nla)		cancel nested attribute construction
 *
 * Attribute Length Calculations:
 *   nla_attr_size(payload)		length of attribute w/o padding
 *   nla_total_size(payload)		length of attribute w/ padding
 *   nla_padlen(payload)		length of padding
 *
 * Attribute Payload Access:
 *   nla_data(nla)			head of attribute payload
 *   nla_len(nla)			length of attribute payload
 *
 * Attribute Payload Access for Basic Types:
 *   nla_get_u8(nla)			get payload for a u8 attribute
 *   nla_get_u16(nla)			get payload for a u16 attribute
 *   nla_get_u32(nla)			get payload for a u32 attribute
 *   nla_get_u64(nla)			get payload for a u64 attribute
 *   nla_get_s8(nla)			get payload for a s8 attribute
 *   nla_get_s16(nla)			get payload for a s16 attribute
 *   nla_get_s32(nla)			get payload for a s32 attribute
 *   nla_get_s64(nla)			get payload for a s64 attribute
 *   nla_get_flag(nla)			return 1 if flag is true
 *   nla_get_msecs(nla)			get payload for a msecs attribute
 *
 * Attribute Misc:
 *   nla_memcpy(dest, nla, count)	copy attribute into memory
 *   nla_memcmp(nla, data, size)	compare attribute with memory area
 *   nla_strscpy(dst, nla, size)	copy attribute to a sized string
 *   nla_strcmp(nla, str)		compare attribute with string
 *
 * Attribute Parsing:
 *   nla_ok(nla, remaining)		does nla fit into remaining bytes?
 *   nla_next(nla, remaining)		get next netlink attribute
 *   nla_validate()			validate a stream of attributes
 *   nla_validate_nested()		validate a stream of nested attributes
 *   nla_find()				find attribute in stream of attributes
 *   nla_find_nested()			find attribute in nested attributes
 *   nla_parse()			parse and validate stream of attrs
 *   nla_parse_nested()			parse nested attributes
 *   nla_for_each_attr()		loop over all attributes
 *   nla_for_each_nested()		loop over the nested attributes
 *=========================================================================
 */

 /**
  * Standard attribute types to specify validation policy
  */
enum {
	NLA_UNSPEC,
	NLA_U8,
	NLA_U16,
	NLA_U32,
	NLA_U64,
	NLA_STRING,
	NLA_FLAG,
	NLA_MSECS,
	NLA_NESTED,
	NLA_NESTED_ARRAY,
	NLA_NUL_STRING,
	NLA_BINARY,
	NLA_S8,
	NLA_S16,
	NLA_S32,
	NLA_S64,
	NLA_BITFIELD32,
	NLA_REJECT,
	NLA_BE16,
	NLA_BE32,
	__NLA_TYPE_MAX,
};

#define NLA_TYPE_MAX (__NLA_TYPE_MAX - 1)

struct netlink_range_validation {
	u64 min, max;
};

struct netlink_range_validation_signed {
	s64 min, max;
};

enum nla_policy_validation {
	NLA_VALIDATE_NONE,
	NLA_VALIDATE_RANGE,
	NLA_VALIDATE_RANGE_WARN_TOO_LONG,
	NLA_VALIDATE_MIN,
	NLA_VALIDATE_MAX,
	NLA_VALIDATE_MASK,
	NLA_VALIDATE_RANGE_PTR,
	NLA_VALIDATE_FUNCTION,
};

/**
 * struct nla_policy - attribute validation policy
 * @type: Type of attribute or NLA_UNSPEC
 * @validation_type: type of attribute validation done in addition to
 *	type-specific validation (e.g. range, function call), see
 *	&enum nla_policy_validation
 * @len: Type specific length of payload
 *
 * Policies are defined as arrays of this struct, the array must be
 * accessible by attribute type up to the highest identifier to be expected.
 *
 * Meaning of `len' field:
 *    NLA_STRING           Maximum length of string
 *    NLA_NUL_STRING       Maximum length of string (excluding NUL)
 *    NLA_FLAG             Unused
 *    NLA_BINARY           Maximum length of attribute payload
 *                         (but see also below with the validation type)
 *    NLA_NESTED,
 *    NLA_NESTED_ARRAY     Length verification is done by checking len of
 *                         nested header (or empty); len field is used if
 *                         nested_policy is also used, for the max attr
 *                         number in the nested policy.
 *    NLA_U8, NLA_U16,
 *    NLA_U32, NLA_U64,
 *    NLA_S8, NLA_S16,
 *    NLA_S32, NLA_S64,
 *    NLA_BE16, NLA_BE32,
 *    NLA_MSECS            Leaving the length field zero will verify the
 *                         given type fits, using it verifies minimum length
 *                         just like "All other"
 *    NLA_BITFIELD32       Unused
 *    NLA_REJECT           Unused
 *    All other            Minimum length of attribute payload
 *
 * Meaning of validation union:
 *    NLA_BITFIELD32       This is a 32-bit bitmap/bitselector attribute and
 *                         `bitfield32_valid' is the u32 value of valid flags
 *    NLA_REJECT           This attribute is always rejected and `reject_message'
 *                         may point to a string to report as the error instead
 *                         of the generic one in extended ACK.
 *    NLA_NESTED           `nested_policy' to a nested policy to validate, must
 *                         also set `len' to the max attribute number. Use the
 *                         provided NLA_POLICY_NESTED() macro.
 *                         Note that nla_parse() will validate, but of course not
 *                         parse, the nested sub-policies.
 *    NLA_NESTED_ARRAY     `nested_policy' points to a nested policy to validate,
 *                         must also set `len' to the max attribute number. Use
 *                         the provided NLA_POLICY_NESTED_ARRAY() macro.
 *                         The difference to NLA_NESTED is the structure:
 *                         NLA_NESTED has the nested attributes directly inside
 *                         while an array has the nested attributes at another
 *                         level down and the attribute types directly in the
 *                         nesting don't matter.
 *    NLA_U8,
 *    NLA_U16,
 *    NLA_U32,
 *    NLA_U64,
 *    NLA_BE16,
 *    NLA_BE32,
 *    NLA_S8,
 *    NLA_S16,
 *    NLA_S32,
 *    NLA_S64              The `min' and `max' fields are used depending on the
 *                         validation_type field, if that is min/max/range then
 *                         the min, max or both are used (respectively) to check
 *                         the value of the integer attribute.
 *                         Note that in the interest of code simplicity and
 *                         struct size both limits are s16, so you cannot
 *                         enforce a range that doesn't fall within the range
 *                         of s16 - do that as usual in the code instead.
 *                         Use the NLA_POLICY_MIN(), NLA_POLICY_MAX() and
 *                         NLA_POLICY_RANGE() macros.
 *    NLA_U8,
 *    NLA_U16,
 *    NLA_U32,
 *    NLA_U64              If the validation_type field instead is set to
 *                         NLA_VALIDATE_RANGE_PTR, `range' must be a pointer
 *                         to a struct netlink_range_validation that indicates
 *                         the min/max values.
 *                         Use NLA_POLICY_FULL_RANGE().
 *    NLA_S8,
 *    NLA_S16,
 *    NLA_S32,
 *    NLA_S64              If the validation_type field instead is set to
 *                         NLA_VALIDATE_RANGE_PTR, `range_signed' must be a
 *                         pointer to a struct netlink_range_validation_signed
 *                         that indicates the min/max values.
 *                         Use NLA_POLICY_FULL_RANGE_SIGNED().
 *
 *    NLA_BINARY           If the validation type is like the ones for integers
 *                         above, then the min/max length (not value like for
 *                         integers) of the attribute is enforced.
 *
 *    All other            Unused - but note that it's a union
 *
 * Meaning of `validate' field, use via NLA_POLICY_VALIDATE_FN:
 *    NLA_BINARY           Validation function called for the attribute.
 *    All other            Unused - but note that it's a union
 *
 * Example:
 *
 * static const u32 myvalidflags = 0xff231023;
 *
 * static const struct nla_policy my_policy[ATTR_MAX+1] = {
 * 	[ATTR_FOO] = { .type = NLA_U16 },
 *	[ATTR_BAR] = { .type = NLA_STRING, .len = BARSIZ },
 *	[ATTR_BAZ] = NLA_POLICY_EXACT_LEN(sizeof(struct mystruct)),
 *	[ATTR_GOO] = NLA_POLICY_BITFIELD32(myvalidflags),
 * };
 */
struct nla_policy {
	u8		type;
	u8		validation_type;
	u16		len;
	union {
		/**
		 * @strict_start_type: first attribute to validate strictly
		 *
		 * This entry is special, and used for the attribute at index 0
		 * only, and specifies special data about the policy, namely it
		 * specifies the "boundary type" where strict length validation
		 * starts for any attribute types >= this value, also, strict
		 * nesting validation starts here.
		 *
		 * Additionally, it means that NLA_UNSPEC is actually NLA_REJECT
		 * for any types >= this, so need to use NLA_POLICY_MIN_LEN() to
		 * get the previous pure { .len = xyz } behaviour. The advantage
		 * of this is that types not specified in the policy will be
		 * rejected.
		 *
		 * For completely new families it should be set to 1 so that the
		 * validation is enforced for all attributes. For existing ones
		 * it should be set at least when new attributes are added to
		 * the enum used by the policy, and be set to the new value that
		 * was added to enforce strict validation from thereon.
		 */
		u16 strict_start_type;

		/* private: use NLA_POLICY_*() to set */
		const u32 bitfield32_valid;
		const u32 mask;
		const char *reject_message;
		const struct nla_policy *nested_policy;
		struct netlink_range_validation *range;
		struct netlink_range_validation_signed *range_signed;
		struct {
			s16 min, max;
		};
		int (*validate)(const struct nlattr *attr,
				struct netlink_ext_ack *extack);
	};
};

#define NLA_POLICY_ETH_ADDR		NLA_POLICY_EXACT_LEN(ETH_ALEN)
#define NLA_POLICY_ETH_ADDR_COMPAT	NLA_POLICY_EXACT_LEN_WARN(ETH_ALEN)

#define _NLA_POLICY_NESTED(maxattr, policy) \
	{ .type = NLA_NESTED, .nested_policy = policy, .len = maxattr }
#define _NLA_POLICY_NESTED_ARRAY(maxattr, policy) \
	{ .type = NLA_NESTED_ARRAY, .nested_policy = policy, .len = maxattr }
#define NLA_POLICY_NESTED(policy) \
	_NLA_POLICY_NESTED(ARRAY_SIZE(policy) - 1, policy)
#define NLA_POLICY_NESTED_ARRAY(policy) \
	_NLA_POLICY_NESTED_ARRAY(ARRAY_SIZE(policy) - 1, policy)
#define NLA_POLICY_BITFIELD32(valid) \
	{ .type = NLA_BITFIELD32, .bitfield32_valid = valid }

#define __NLA_IS_UINT_TYPE(tp)						\
	(tp == NLA_U8 || tp == NLA_U16 || tp == NLA_U32 || tp == NLA_U64)
#define __NLA_IS_SINT_TYPE(tp)						\
	(tp == NLA_S8 || tp == NLA_S16 || tp == NLA_S32 || tp == NLA_S64)
#define __NLA_IS_BEINT_TYPE(tp)						\
	(tp == NLA_BE16 || tp == NLA_BE32)

#define __NLA_ENSURE(condition) BUILD_BUG_ON_ZERO(!(condition))
#define NLA_ENSURE_UINT_TYPE(tp)			\
	(__NLA_ENSURE(__NLA_IS_UINT_TYPE(tp)) + tp)
#define NLA_ENSURE_UINT_OR_BINARY_TYPE(tp)		\
	(__NLA_ENSURE(__NLA_IS_UINT_TYPE(tp) ||	\
		      tp == NLA_MSECS ||		\
		      tp == NLA_BINARY) + tp)
#define NLA_ENSURE_SINT_TYPE(tp)			\
	(__NLA_ENSURE(__NLA_IS_SINT_TYPE(tp)) + tp)
#define NLA_ENSURE_INT_OR_BINARY_TYPE(tp)		\
	(__NLA_ENSURE(__NLA_IS_UINT_TYPE(tp) ||		\
		      __NLA_IS_SINT_TYPE(tp) ||		\
		      __NLA_IS_BEINT_TYPE(tp) ||	\
		      tp == NLA_MSECS ||		\
		      tp == NLA_BINARY) + tp)
#define NLA_ENSURE_NO_VALIDATION_PTR(tp)		\
	(__NLA_ENSURE(tp != NLA_BITFIELD32 &&		\
		      tp != NLA_REJECT &&		\
		      tp != NLA_NESTED &&		\
		      tp != NLA_NESTED_ARRAY) + tp)
#define NLA_ENSURE_BEINT_TYPE(tp)			\
	(__NLA_ENSURE(__NLA_IS_BEINT_TYPE(tp)) + tp)

#define NLA_POLICY_RANGE(tp, _min, _max) {		\
	.type = NLA_ENSURE_INT_OR_BINARY_TYPE(tp),	\
	.validation_type = NLA_VALIDATE_RANGE,		\
	.min = _min,					\
	.max = _max					\
}

#define NLA_POLICY_FULL_RANGE(tp, _range) {		\
	.type = NLA_ENSURE_UINT_OR_BINARY_TYPE(tp),	\
	.validation_type = NLA_VALIDATE_RANGE_PTR,	\
	.range = _range,				\
}

#define NLA_POLICY_FULL_RANGE_SIGNED(tp, _range) {	\
	.type = NLA_ENSURE_SINT_TYPE(tp),		\
	.validation_type = NLA_VALIDATE_RANGE_PTR,	\
	.range_signed = _range,				\
}

#define NLA_POLICY_MIN(tp, _min) {			\
	.type = NLA_ENSURE_INT_OR_BINARY_TYPE(tp),	\
	.validation_type = NLA_VALIDATE_MIN,		\
	.min = _min,					\
}

#define NLA_POLICY_MAX(tp, _max) {			\
	.type = NLA_ENSURE_INT_OR_BINARY_TYPE(tp),	\
	.validation_type = NLA_VALIDATE_MAX,		\
	.max = _max,					\
}

#define NLA_POLICY_MASK(tp, _mask) {			\
	.type = NLA_ENSURE_UINT_TYPE(tp),		\
	.validation_type = NLA_VALIDATE_MASK,		\
	.mask = _mask,					\
}

#define NLA_POLICY_VALIDATE_FN(tp, fn, ...) {		\
	.type = NLA_ENSURE_NO_VALIDATION_PTR(tp),	\
	.validation_type = NLA_VALIDATE_FUNCTION,	\
	.validate = fn,					\
	.len = __VA_ARGS__ + 0,				\
}

#define NLA_POLICY_EXACT_LEN(_len)	NLA_POLICY_RANGE(NLA_BINARY, _len, _len)
#define NLA_POLICY_EXACT_LEN_WARN(_len) {			\
	.type = NLA_BINARY,					\
	.validation_type = NLA_VALIDATE_RANGE_WARN_TOO_LONG,	\
	.min = _len,						\
	.max = _len						\
}
#define NLA_POLICY_MIN_LEN(_len)	NLA_POLICY_MIN(NLA_BINARY, _len)

/**
 * struct nl_info - netlink source information
 * @nlh: Netlink message header of original request
 * @nl_net: Network namespace
 * @portid: Netlink PORTID of requesting application
 * @skip_notify: Skip netlink notifications to user space
 * @skip_notify_kernel: Skip selected in-kernel notifications
 */
struct nl_info {
	struct nlmsghdr		*nlh;
	struct net		*nl_net;
	u32			portid;
	u8			skip_notify:1,
				skip_notify_kernel:1;
};

/**
 * enum netlink_validation - netlink message/attribute validation levels
 * @NL_VALIDATE_LIBERAL: Old-style "be liberal" validation, not caring about
 *	extra data at the end of the message, attributes being longer than
 *	they should be, or unknown attributes being present.
 * @NL_VALIDATE_TRAILING: Reject junk data encountered after attribute parsing.
 * @NL_VALIDATE_MAXTYPE: Reject attributes > max type; Together with _TRAILING
 *	this is equivalent to the old nla_parse_strict()/nlmsg_parse_strict().
 * @NL_VALIDATE_UNSPEC: Reject attributes with NLA_UNSPEC in the policy.
 *	This can safely be set by the kernel when the given policy has no
 *	NLA_UNSPEC anymore, and can thus be used to ensure policy entries
 *	are enforced going forward.
 * @NL_VALIDATE_STRICT_ATTRS: strict attribute policy parsing (e.g.
 *	U8, U16, U32 must have exact size, etc.)
 * @NL_VALIDATE_NESTED: Check that NLA_F_NESTED is set for NLA_NESTED(_ARRAY)
 *	and unset for other policies.
 */
enum netlink_validation {
	NL_VALIDATE_LIBERAL = 0,
	NL_VALIDATE_TRAILING = BIT(0),
	NL_VALIDATE_MAXTYPE = BIT(1),
	NL_VALIDATE_UNSPEC = BIT(2),
	NL_VALIDATE_STRICT_ATTRS = BIT(3),
	NL_VALIDATE_NESTED = BIT(4),
};

#define NL_VALIDATE_DEPRECATED_STRICT (NL_VALIDATE_TRAILING |\
				       NL_VALIDATE_MAXTYPE)
#define NL_VALIDATE_STRICT (NL_VALIDATE_TRAILING |\
			    NL_VALIDATE_MAXTYPE |\
			    NL_VALIDATE_UNSPEC |\
			    NL_VALIDATE_STRICT_ATTRS |\
			    NL_VALIDATE_NESTED)

int netlink_rcv_skb(struct sk_buff *skb,
		    int (*cb)(struct sk_buff *, struct nlmsghdr *,
			      struct netlink_ext_ack *));
int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
		 unsigned int group, int report, gfp_t flags);

int __nla_validate(const struct nlattr *head, int len, int maxtype,
		   const struct nla_policy *policy, unsigned int validate,
		   struct netlink_ext_ack *extack);
int __nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
		int len, const struct nla_policy *policy, unsigned int validate,
		struct netlink_ext_ack *extack);
int nla_policy_len(const struct nla_policy *, int);
struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype);
ssize_t nla_strscpy(char *dst, const struct nlattr *nla, size_t dstsize);
char *nla_strdup(const struct nlattr *nla, gfp_t flags);
int nla_memcpy(void *dest, const struct nlattr *src, int count);
int nla_memcmp(const struct nlattr *nla, const void *data, size_t size);
int nla_strcmp(const struct nlattr *nla, const char *str);
struct nlattr *__nla_reserve(struct sk_buff *skb, int attrtype, int attrlen);
struct nlattr *__nla_reserve_64bit(struct sk_buff *skb, int attrtype,
				   int attrlen, int padattr);
void *__nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
struct nlattr *nla_reserve(struct sk_buff *skb, int attrtype, int attrlen);
struct nlattr *nla_reserve_64bit(struct sk_buff *skb, int attrtype,
				 int attrlen, int padattr);
void *nla_reserve_nohdr(struct sk_buff *skb, int attrlen);
void __nla_put(struct sk_buff *skb, int attrtype, int attrlen,
	       const void *data);
void __nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
		     const void *data, int padattr);
void __nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);
int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data);
int nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen,
		  const void *data, int padattr);
int nla_put_nohdr(struct sk_buff *skb, int attrlen, const void *data);
int nla_append(struct sk_buff *skb, int attrlen, const void *data);

/**************************************************************************
 * Netlink Messages
 **************************************************************************/

/**
 * nlmsg_msg_size - length of netlink message not including padding
 * @payload: length of message payload
 */
static inline int nlmsg_msg_size(int payload)
{
	return NLMSG_HDRLEN + payload;
}

/**
 * nlmsg_total_size - length of netlink message including padding
 * @payload: length of message payload
 */
static inline int nlmsg_total_size(int payload)
{
	return NLMSG_ALIGN(nlmsg_msg_size(payload));
}

/**
 * nlmsg_padlen - length of padding at the message's tail
 * @payload: length of message payload
 */
static inline int nlmsg_padlen(int payload)
{
	return nlmsg_total_size(payload) - nlmsg_msg_size(payload);
}

/**
 * nlmsg_data - head of message payload
 * @nlh: netlink message header
 */
static inline void *nlmsg_data(const struct nlmsghdr *nlh)
{
	return (unsigned char *) nlh + NLMSG_HDRLEN;
}

/**
 * nlmsg_len - length of message payload
 * @nlh: netlink message header
 */
static inline int nlmsg_len(const struct nlmsghdr *nlh)
{
	return nlh->nlmsg_len - NLMSG_HDRLEN;
}

/**
 * nlmsg_attrdata - head of attributes data
 * @nlh: netlink message header
 * @hdrlen: length of family specific header
 */
static inline struct nlattr *nlmsg_attrdata(const struct nlmsghdr *nlh,
					    int hdrlen)
{
	unsigned char *data = nlmsg_data(nlh);
	return (struct nlattr *) (data + NLMSG_ALIGN(hdrlen));
}

/**
 * nlmsg_attrlen - length of attributes data
 * @nlh: netlink message header
 * @hdrlen: length of family specific header
 */
static inline int nlmsg_attrlen(const struct nlmsghdr *nlh, int hdrlen)
{
	return nlmsg_len(nlh) - NLMSG_ALIGN(hdrlen);
}

/**
 * nlmsg_ok - check if the netlink message fits into the remaining bytes
 * @nlh: netlink message header
 * @remaining: number of bytes remaining in message stream
 */
static inline int nlmsg_ok(const struct nlmsghdr *nlh, int remaining)
{
	return (remaining >= (int) sizeof(struct nlmsghdr) &&
		nlh->nlmsg_len >= sizeof(struct nlmsghdr) &&
		nlh->nlmsg_len <= remaining);
}

/**
 * nlmsg_next - next netlink message in message stream
 * @nlh: netlink message header
 * @remaining: number of bytes remaining in message stream
 *
 * Returns the next netlink message in the message stream and
 * decrements remaining by the size of the current message.
 */
static inline struct nlmsghdr *
nlmsg_next(const struct nlmsghdr *nlh, int *remaining)
{
	int totlen = NLMSG_ALIGN(nlh->nlmsg_len);

	*remaining -= totlen;

	return (struct nlmsghdr *) ((unsigned char *) nlh + totlen);
}

/**
 * nla_parse - Parse a stream of attributes into a tb buffer
 * @tb: destination array with maxtype+1 elements
 * @maxtype: maximum attribute type to be expected
 * @head: head of attribute stream
 * @len: length of attribute stream
 * @policy: validation policy
 * @extack: extended ACK pointer
 *
 * Parses a stream of attributes and stores a pointer to each attribute in
 * the tb array accessible via the attribute type. Attributes with a type
 * exceeding maxtype will be rejected, policy must be specified, attributes
 * will be validated in the strictest way possible.
 *
 * Returns 0 on success or a negative error code.
 */
static inline int nla_parse(struct nlattr **tb, int maxtype,
			    const struct nlattr *head, int len,
			    const struct nla_policy *policy,
			    struct netlink_ext_ack *extack)
{
	return __nla_parse(tb, maxtype, head, len, policy,
			   NL_VALIDATE_STRICT, extack);
}

/**
 * nla_parse_deprecated - Parse a stream of attributes into a tb buffer
 * @tb: destination array with maxtype+1 elements
 * @maxtype: maximum attribute type to be expected
 * @head: head of attribute stream
 * @len: length of attribute stream
 * @policy: validation policy
 * @extack: extended ACK pointer
 *
 * Parses a stream of attributes and stores a pointer to each attribute in
 * the tb array accessible via the attribute type. Attributes with a type
 * exceeding maxtype will be ignored and attributes from the policy are not
 * always strictly validated (only for new attributes).
 *
 * Returns 0 on success or a negative error code.
 */
static inline int nla_parse_deprecated(struct nlattr **tb, int maxtype,
				       const struct nlattr *head, int len,
				       const struct nla_policy *policy,
				       struct netlink_ext_ack *extack)
{
	return __nla_parse(tb, maxtype, head, len, policy,
			   NL_VALIDATE_LIBERAL, extack);
}

/**
 * nla_parse_deprecated_strict - Parse a stream of attributes into a tb buffer
 * @tb: destination array with maxtype+1 elements
 * @maxtype: maximum attribute type to be expected
 * @head: head of attribute stream
 * @len: length of attribute stream
 * @policy: validation policy
 * @extack: extended ACK pointer
 *
 * Parses a stream of attributes and stores a pointer to each attribute in
 * the tb array accessible via the attribute type. Attributes with a type
 * exceeding maxtype will be rejected as well as trailing data, but the
 * policy is not completely strictly validated (only for new attributes).
 *
 * Returns 0 on success or a negative error code.
 */
static inline int nla_parse_deprecated_strict(struct nlattr **tb, int maxtype,
					      const struct nlattr *head,
					      int len,
					      const struct nla_policy *policy,
					      struct netlink_ext_ack *extack)
{
	return __nla_parse(tb, maxtype, head, len, policy,
			   NL_VALIDATE_DEPRECATED_STRICT, extack);
}

/**
 * __nlmsg_parse - parse attributes of a netlink message
 * @nlh: netlink message header
 * @hdrlen: length of family specific header
 * @tb: destination array with maxtype+1 elements
 * @maxtype: maximum attribute type to be expected
 * @policy: validation policy
 * @validate: validation strictness
 * @extack: extended ACK report struct
 *
 * See nla_parse()
 */
static inline int __nlmsg_parse(const struct nlmsghdr *nlh, int hdrlen,
				struct nlattr *tb[], int maxtype,
				const struct nla_policy *policy,
				unsigned int validate,
				struct netlink_ext_ack *extack)
{
	if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) {
		NL_SET_ERR_MSG(extack, "Invalid header length");
		return -EINVAL;
	}

	return __nla_parse(tb, maxtype, nlmsg_attrdata(nlh, hdrlen),
			   nlmsg_attrlen(nlh, hdrlen), policy, validate,
			   extack);
}

/**
 * nlmsg_parse - parse attributes of a netlink message
 * @nlh: netlink message header
 * @hdrlen: length of family specific header
 * @tb: destination array with maxtype+1 elements
 * @maxtype: maximum attribute type to be expected
 * @policy: validation policy
 * @extack: extended ACK report struct
 *
 * See nla_parse()
 */
static inline int nlmsg_parse(const struct nlmsghdr *nlh, int hdrlen,
			      struct nlattr *tb[], int maxtype,
			      const struct nla_policy *policy,
			      struct netlink_ext_ack *extack)
{
	return __nlmsg_parse(nlh, hdrlen, tb, maxtype, policy,
			     NL_VALIDATE_STRICT, extack);
}

/**
 * nlmsg_parse_deprecated - parse attributes of a netlink message
 * @nlh: netlink message header
 * @hdrlen: length of family specific header
 * @tb: destination array with maxtype+1 elements
 * @maxtype: maximum attribute type to be expected
 * @policy: validation policy
 * @extack: extended ACK report struct
 *
 * See nla_parse_deprecated()
 */
static inline int nlmsg_parse_deprecated(const struct nlmsghdr *nlh, int hdrlen,
					 struct nlattr *tb[], int maxtype,
					 const struct nla_policy *policy,
					 struct netlink_ext_ack *extack)
{
	return __nlmsg_parse(nlh, hdrlen, tb, maxtype, policy,
			     NL_VALIDATE_LIBERAL, extack);
}

/**
 * nlmsg_parse_deprecated_strict - parse attributes of a netlink message
 * @nlh: netlink message header
 * @hdrlen: length of family specific header
 * @tb: destination array with maxtype+1 elements
 * @maxtype: maximum attribute type to be expected
 * @policy: validation policy
 * @extack: extended ACK report struct
 *
 * See nla_parse_deprecated_strict()
 */
static inline int
nlmsg_parse_deprecated_strict(const struct nlmsghdr *nlh, int hdrlen,
			      struct nlattr *tb[], int maxtype,
			      const struct nla_policy *policy,
			      struct netlink_ext_ack *extack)
{
	return __nlmsg_parse(nlh, hdrlen, tb, maxtype, policy,
			     NL_VALIDATE_DEPRECATED_STRICT, extack);
}

/**
 * nlmsg_find_attr - find a specific attribute in a netlink message
 * @nlh: netlink message header
 * @hdrlen: length of familiy specific header
 * @attrtype: type of attribute to look for
 *
 * Returns the first attribute which matches the specified type.
 */
static inline struct nlattr *nlmsg_find_attr(const struct nlmsghdr *nlh,
					     int hdrlen, int attrtype)
{
	return nla_find(nlmsg_attrdata(nlh, hdrlen),
			nlmsg_attrlen(nlh, hdrlen), attrtype);
}

/**
 * nla_validate_deprecated - Validate a stream of attributes
 * @head: head of attribute stream
 * @len: length of attribute stream
 * @maxtype: maximum attribute type to be expected
 * @policy: validation policy
 * @extack: extended ACK report struct
 *
 * Validates all attributes in the specified attribute stream against the
 * specified policy. Validation is done in liberal mode.
 * See documenation of struct nla_policy for more details.
 *
 * Returns 0 on success or a negative error code.
 */
static inline int nla_validate_deprecated(const struct nlattr *head, int len,
					  int maxtype,
					  const struct nla_policy *policy,
					  struct netlink_ext_ack *extack)
{
	return __nla_validate(head, len, maxtype, policy, NL_VALIDATE_LIBERAL,
			      extack);
}

/**
 * nla_validate - Validate a stream of attributes
 * @head: head of attribute stream
 * @len: length of attribute stream
 * @maxtype: maximum attribute type to be expected
 * @policy: validation policy
 * @extack: extended ACK report struct
 *
 * Validates all attributes in the specified attribute stream against the
 * specified policy. Validation is done in strict mode.
 * See documenation of struct nla_policy for more details.
 *
 * Returns 0 on success or a negative error code.
 */
static inline int nla_validate(const struct nlattr *head, int len, int maxtype,
			       const struct nla_policy *policy,
			       struct netlink_ext_ack *extack)
{
	return __nla_validate(head, len, maxtype, policy, NL_VALIDATE_STRICT,
			      extack);
}

/**
 * nlmsg_validate_deprecated - validate a netlink message including attributes
 * @nlh: netlinket message header
 * @hdrlen: length of familiy specific header
 * @maxtype: maximum attribute type to be expected
 * @policy: validation policy
 * @extack: extended ACK report struct
 */
static inline int nlmsg_validate_deprecated(const struct nlmsghdr *nlh,
					    int hdrlen, int maxtype,
					    const struct nla_policy *policy,
					    struct netlink_ext_ack *extack)
{
	if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))
		return -EINVAL;

	return __nla_validate(nlmsg_attrdata(nlh, hdrlen),
			      nlmsg_attrlen(nlh, hdrlen), maxtype,
			      policy, NL_VALIDATE_LIBERAL, extack);
}



/**
 * nlmsg_report - need to report back to application?
 * @nlh: netlink message header
 *
 * Returns 1 if a report back to the application is requested.
 */
static inline int nlmsg_report(const struct nlmsghdr *nlh)
{
	return nlh ? !!(nlh->nlmsg_flags & NLM_F_ECHO) : 0;
}

/**
 * nlmsg_for_each_attr - iterate over a stream of attributes
 * @pos: loop counter, set to current attribute
 * @nlh: netlink message header
 * @hdrlen: length of familiy specific header
 * @rem: initialized to len, holds bytes currently remaining in stream
 */
#define nlmsg_for_each_attr(pos, nlh, hdrlen, rem) \
	nla_for_each_attr(pos, nlmsg_attrdata(nlh, hdrlen), \
			  nlmsg_attrlen(nlh, hdrlen), rem)

/**
 * nlmsg_put - Add a new netlink message to an skb
 * @skb: socket buffer to store message in
 * @portid: netlink PORTID of requesting application
 * @seq: sequence number of message
 * @type: message type
 * @payload: length of message payload
 * @flags: message flags
 *
 * Returns NULL if the tailroom of the skb is insufficient to store
 * the message header and payload.
 */
static inline struct nlmsghdr *nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
					 int type, int payload, int flags)
{
	if (unlikely(skb_tailroom(skb) < nlmsg_total_size(payload)))
		return NULL;

	return __nlmsg_put(skb, portid, seq, type, payload, flags);
}

/**
 * nlmsg_put_answer - Add a new callback based netlink message to an skb
 * @skb: socket buffer to store message in
 * @cb: netlink callback
 * @type: message type
 * @payload: length of message payload
 * @flags: message flags
 *
 * Returns NULL if the tailroom of the skb is insufficient to store
 * the message header and payload.
 */
static inline struct nlmsghdr *nlmsg_put_answer(struct sk_buff *skb,
						struct netlink_callback *cb,
						int type, int payload,
						int flags)
{
	return nlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
			 type, payload, flags);
}

/**
 * nlmsg_new - Allocate a new netlink message
 * @payload: size of the message payload
 * @flags: the type of memory to allocate.
 *
 * Use NLMSG_DEFAULT_SIZE if the size of the payload isn't known
 * and a good default is needed.
 */
static inline struct sk_buff *nlmsg_new(size_t payload, gfp_t flags)
{
	return alloc_skb(nlmsg_total_size(payload), flags);
}

/**
 * nlmsg_end - Finalize a netlink message
 * @skb: socket buffer the message is stored in
 * @nlh: netlink message header
 *
 * Corrects the netlink message header to include the appeneded
 * attributes. Only necessary if attributes have been added to
 * the message.
 */
static inline void nlmsg_end(struct sk_buff *skb, struct nlmsghdr *nlh)
{
	nlh->nlmsg_len = skb_tail_pointer(skb) - (unsigned char *)nlh;
}

/**
 * nlmsg_get_pos - return current position in netlink message
 * @skb: socket buffer the message is stored in
 *
 * Returns a pointer to the current tail of the message.
 */
static inline void *nlmsg_get_pos(struct sk_buff *skb)
{
	return skb_tail_pointer(skb);
}

/**
 * nlmsg_trim - Trim message to a mark
 * @skb: socket buffer the message is stored in
 * @mark: mark to trim to
 *
 * Trims the message to the provided mark.
 */
static inline void nlmsg_trim(struct sk_buff *skb, const void *mark)
{
	if (mark) {
		WARN_ON((unsigned char *) mark < skb->data);
		skb_trim(skb, (unsigned char *) mark - skb->data);
	}
}

/**
 * nlmsg_cancel - Cancel construction of a netlink message
 * @skb: socket buffer the message is stored in
 * @nlh: netlink message header
 *
 * Removes the complete netlink message including all
 * attributes from the socket buffer again.
 */
static inline void nlmsg_cancel(struct sk_buff *skb, struct nlmsghdr *nlh)
{
	nlmsg_trim(skb, nlh);
}

/**
 * nlmsg_free - free a netlink message
 * @skb: socket buffer of netlink message
 */
static inline void nlmsg_free(struct sk_buff *skb)
{
	kfree_skb(skb);
}

/**
 * nlmsg_multicast - multicast a netlink message
 * @sk: netlink socket to spread messages to
 * @skb: netlink message as socket buffer
 * @portid: own netlink portid to avoid sending to yourself
 * @group: multicast group id
 * @flags: allocation flags
 */
static inline int nlmsg_multicast(struct sock *sk, struct sk_buff *skb,
				  u32 portid, unsigned int group, gfp_t flags)
{
	int err;

	NETLINK_CB(skb).dst_group = group;

	err = netlink_broadcast(sk, skb, portid, group, flags);
	if (err > 0)
		err = 0;

	return err;
}

/**
 * nlmsg_unicast - unicast a netlink message
 * @sk: netlink socket to spread message to
 * @skb: netlink message as socket buffer
 * @portid: netlink portid of the destination socket
 */
static inline int nlmsg_unicast(struct sock *sk, struct sk_buff *skb, u32 portid)
{
	int err;

	err = netlink_unicast(sk, skb, portid, MSG_DONTWAIT);
	if (err > 0)
		err = 0;

	return err;
}

/**
 * nlmsg_for_each_msg - iterate over a stream of messages
 * @pos: loop counter, set to current message
 * @head: head of message stream
 * @len: length of message stream
 * @rem: initialized to len, holds bytes currently remaining in stream
 */
#define nlmsg_for_each_msg(pos, head, len, rem) \
	for (pos = head, rem = len; \
	     nlmsg_ok(pos, rem); \
	     pos = nlmsg_next(pos, &(rem)))

/**
 * nl_dump_check_consistent - check if sequence is consistent and advertise if not
 * @cb: netlink callback structure that stores the sequence number
 * @nlh: netlink message header to write the flag to
 *
 * This function checks if the sequence (generation) number changed during dump
 * and if it did, advertises it in the netlink message header.
 *
 * The correct way to use it is to set cb->seq to the generation counter when
 * all locks for dumping have been acquired, and then call this function for
 * each message that is generated.
 *
 * Note that due to initialisation concerns, 0 is an invalid sequence number
 * and must not be used by code that uses this functionality.
 */
static inline void
nl_dump_check_consistent(struct netlink_callback *cb,
			 struct nlmsghdr *nlh)
{
	if (cb->prev_seq && cb->seq != cb->prev_seq)
		nlh->nlmsg_flags |= NLM_F_DUMP_INTR;
	cb->prev_seq = cb->seq;
}

/**************************************************************************
 * Netlink Attributes
 **************************************************************************/

/**
 * nla_attr_size - length of attribute not including padding
 * @payload: length of payload
 */
static inline int nla_attr_size(int payload)
{
	return NLA_HDRLEN + payload;
}

/**
 * nla_total_size - total length of attribute including padding
 * @payload: length of payload
 */
static inline int nla_total_size(int payload)
{
	return NLA_ALIGN(nla_attr_size(payload));
}

/**
 * nla_padlen - length of padding at the tail of attribute
 * @payload: length of payload
 */
static inline int nla_padlen(int payload)
{
	return nla_total_size(payload) - nla_attr_size(payload);
}

/**
 * nla_type - attribute type
 * @nla: netlink attribute
 */
static inline int nla_type(const struct nlattr *nla)
{
	return nla->nla_type & NLA_TYPE_MASK;
}

/**
 * nla_data - head of payload
 * @nla: netlink attribute
 */
static inline void *nla_data(const struct nlattr *nla)
{
	return (char *) nla + NLA_HDRLEN;
}

/**
 * nla_len - length of payload
 * @nla: netlink attribute
 */
static inline int nla_len(const struct nlattr *nla)
{
	return nla->nla_len - NLA_HDRLEN;
}

/**
 * nla_ok - check if the netlink attribute fits into the remaining bytes
 * @nla: netlink attribute
 * @remaining: number of bytes remaining in attribute stream
 */
static inline int nla_ok(const struct nlattr *nla, int remaining)
{
	return remaining >= (int) sizeof(*nla) &&
	       nla->nla_len >= sizeof(*nla) &&
	       nla->nla_len <= remaining;
}

/**
 * nla_next - next netlink attribute in attribute stream
 * @nla: netlink attribute
 * @remaining: number of bytes remaining in attribute stream
 *
 * Returns the next netlink attribute in the attribute stream and
 * decrements remaining by the size of the current attribute.
 */
static inline struct nlattr *nla_next(const struct nlattr *nla, int *remaining)
{
	unsigned int totlen = NLA_ALIGN(nla->nla_len);

	*remaining -= totlen;
	return (struct nlattr *) ((char *) nla + totlen);
}

/**
 * nla_find_nested - find attribute in a set of nested attributes
 * @nla: attribute containing the nested attributes
 * @attrtype: type of attribute to look for
 *
 * Returns the first attribute which matches the specified type.
 */
static inline struct nlattr *
nla_find_nested(const struct nlattr *nla, int attrtype)
{
	return nla_find(nla_data(nla), nla_len(nla), attrtype);
}

/**
 * nla_parse_nested - parse nested attributes
 * @tb: destination array with maxtype+1 elements
 * @maxtype: maximum attribute type to be expected
 * @nla: attribute containing the nested attributes
 * @policy: validation policy
 * @extack: extended ACK report struct
 *
 * See nla_parse()
 */
static inline int nla_parse_nested(struct nlattr *tb[], int maxtype,
				   const struct nlattr *nla,
				   const struct nla_policy *policy,
				   struct netlink_ext_ack *extack)
{
	if (!(nla->nla_type & NLA_F_NESTED)) {
		NL_SET_ERR_MSG_ATTR(extack, nla, "NLA_F_NESTED is missing");
		return -EINVAL;
	}

	return __nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy,
			   NL_VALIDATE_STRICT, extack);
}

/**
 * nla_parse_nested_deprecated - parse nested attributes
 * @tb: destination array with maxtype+1 elements
 * @maxtype: maximum attribute type to be expected
 * @nla: attribute containing the nested attributes
 * @policy: validation policy
 * @extack: extended ACK report struct
 *
 * See nla_parse_deprecated()
 */
static inline int nla_parse_nested_deprecated(struct nlattr *tb[], int maxtype,
					      const struct nlattr *nla,
					      const struct nla_policy *policy,
					      struct netlink_ext_ack *extack)
{
	return __nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy,
			   NL_VALIDATE_LIBERAL, extack);
}

/**
 * nla_put_u8 - Add a u8 netlink attribute to a socket buffer
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 * @value: numeric value
 */
static inline int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value)
{
	/* temporary variables to work around GCC PR81715 with asan-stack=1 */
	u8 tmp = value;

	return nla_put(skb, attrtype, sizeof(u8), &tmp);
}

/**
 * nla_put_u16 - Add a u16 netlink attribute to a socket buffer
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 * @value: numeric value
 */
static inline int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value)
{
	u16 tmp = value;

	return nla_put(skb, attrtype, sizeof(u16), &tmp);
}

/**
 * nla_put_be16 - Add a __be16 netlink attribute to a socket buffer
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 * @value: numeric value
 */
static inline int nla_put_be16(struct sk_buff *skb, int attrtype, __be16 value)
{
	__be16 tmp = value;

	return nla_put(skb, attrtype, sizeof(__be16), &tmp);
}

/**
 * nla_put_net16 - Add 16-bit network byte order netlink attribute to a socket buffer
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 * @value: numeric value
 */
static inline int nla_put_net16(struct sk_buff *skb, int attrtype, __be16 value)
{
	__be16 tmp = value;

	return nla_put_be16(skb, attrtype | NLA_F_NET_BYTEORDER, tmp);
}

/**
 * nla_put_le16 - Add a __le16 netlink attribute to a socket buffer
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 * @value: numeric value
 */
static inline int nla_put_le16(struct sk_buff *skb, int attrtype, __le16 value)
{
	__le16 tmp = value;

	return nla_put(skb, attrtype, sizeof(__le16), &tmp);
}

/**
 * nla_put_u32 - Add a u32 netlink attribute to a socket buffer
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 * @value: numeric value
 */
static inline int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value)
{
	u32 tmp = value;

	return nla_put(skb, attrtype, sizeof(u32), &tmp);
}

/**
 * nla_put_be32 - Add a __be32 netlink attribute to a socket buffer
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 * @value: numeric value
 */
static inline int nla_put_be32(struct sk_buff *skb, int attrtype, __be32 value)
{
	__be32 tmp = value;

	return nla_put(skb, attrtype, sizeof(__be32), &tmp);
}

/**
 * nla_put_net32 - Add 32-bit network byte order netlink attribute to a socket buffer
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 * @value: numeric value
 */
static inline int nla_put_net32(struct sk_buff *skb, int attrtype, __be32 value)
{
	__be32 tmp = value;

	return nla_put_be32(skb, attrtype | NLA_F_NET_BYTEORDER, tmp);
}

/**
 * nla_put_le32 - Add a __le32 netlink attribute to a socket buffer
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 * @value: numeric value
 */
static inline int nla_put_le32(struct sk_buff *skb, int attrtype, __le32 value)
{
	__le32 tmp = value;

	return nla_put(skb, attrtype, sizeof(__le32), &tmp);
}

/**
 * nla_put_u64_64bit - Add a u64 netlink attribute to a skb and align it
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 * @value: numeric value
 * @padattr: attribute type for the padding
 */
static inline int nla_put_u64_64bit(struct sk_buff *skb, int attrtype,
				    u64 value, int padattr)
{
	u64 tmp = value;

	return nla_put_64bit(skb, attrtype, sizeof(u64), &tmp, padattr);
}

/**
 * nla_put_be64 - Add a __be64 netlink attribute to a socket buffer and align it
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 * @value: numeric value
 * @padattr: attribute type for the padding
 */
static inline int nla_put_be64(struct sk_buff *skb, int attrtype, __be64 value,
			       int padattr)
{
	__be64 tmp = value;

	return nla_put_64bit(skb, attrtype, sizeof(__be64), &tmp, padattr);
}

/**
 * nla_put_net64 - Add 64-bit network byte order nlattr to a skb and align it
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 * @value: numeric value
 * @padattr: attribute type for the padding
 */
static inline int nla_put_net64(struct sk_buff *skb, int attrtype, __be64 value,
				int padattr)
{
	__be64 tmp = value;

	return nla_put_be64(skb, attrtype | NLA_F_NET_BYTEORDER, tmp,
			    padattr);
}

/**
 * nla_put_le64 - Add a __le64 netlink attribute to a socket buffer and align it
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 * @value: numeric value
 * @padattr: attribute type for the padding
 */
static inline int nla_put_le64(struct sk_buff *skb, int attrtype, __le64 value,
			       int padattr)
{
	__le64 tmp = value;

	return nla_put_64bit(skb, attrtype, sizeof(__le64), &tmp, padattr);
}

/**
 * nla_put_s8 - Add a s8 netlink attribute to a socket buffer
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 * @value: numeric value
 */
static inline int nla_put_s8(struct sk_buff *skb, int attrtype, s8 value)
{
	s8 tmp = value;

	return nla_put(skb, attrtype, sizeof(s8), &tmp);
}

/**
 * nla_put_s16 - Add a s16 netlink attribute to a socket buffer
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 * @value: numeric value
 */
static inline int nla_put_s16(struct sk_buff *skb, int attrtype, s16 value)
{
	s16 tmp = value;

	return nla_put(skb, attrtype, sizeof(s16), &tmp);
}

/**
 * nla_put_s32 - Add a s32 netlink attribute to a socket buffer
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 * @value: numeric value
 */
static inline int nla_put_s32(struct sk_buff *skb, int attrtype, s32 value)
{
	s32 tmp = value;

	return nla_put(skb, attrtype, sizeof(s32), &tmp);
}

/**
 * nla_put_s64 - Add a s64 netlink attribute to a socket buffer and align it
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 * @value: numeric value
 * @padattr: attribute type for the padding
 */
static inline int nla_put_s64(struct sk_buff *skb, int attrtype, s64 value,
			      int padattr)
{
	s64 tmp = value;

	return nla_put_64bit(skb, attrtype, sizeof(s64), &tmp, padattr);
}

/**
 * nla_put_string - Add a string netlink attribute to a socket buffer
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 * @str: NUL terminated string
 */
static inline int nla_put_string(struct sk_buff *skb, int attrtype,
				 const char *str)
{
	return nla_put(skb, attrtype, strlen(str) + 1, str);
}

/**
 * nla_put_flag - Add a flag netlink attribute to a socket buffer
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 */
static inline int nla_put_flag(struct sk_buff *skb, int attrtype)
{
	return nla_put(skb, attrtype, 0, NULL);
}

/**
 * nla_put_msecs - Add a msecs netlink attribute to a skb and align it
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 * @njiffies: number of jiffies to convert to msecs
 * @padattr: attribute type for the padding
 */
static inline int nla_put_msecs(struct sk_buff *skb, int attrtype,
				unsigned long njiffies, int padattr)
{
	u64 tmp = jiffies_to_msecs(njiffies);

	return nla_put_64bit(skb, attrtype, sizeof(u64), &tmp, padattr);
}

/**
 * nla_put_in_addr - Add an IPv4 address netlink attribute to a socket
 * buffer
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 * @addr: IPv4 address
 */
static inline int nla_put_in_addr(struct sk_buff *skb, int attrtype,
				  __be32 addr)
{
	__be32 tmp = addr;

	return nla_put_be32(skb, attrtype, tmp);
}

/**
 * nla_put_in6_addr - Add an IPv6 address netlink attribute to a socket
 * buffer
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 * @addr: IPv6 address
 */
static inline int nla_put_in6_addr(struct sk_buff *skb, int attrtype,
				   const struct in6_addr *addr)
{
	return nla_put(skb, attrtype, sizeof(*addr), addr);
}

/**
 * nla_put_bitfield32 - Add a bitfield32 netlink attribute to a socket buffer
 * @skb: socket buffer to add attribute to
 * @attrtype: attribute type
 * @value: value carrying bits
 * @selector: selector of valid bits
 */
static inline int nla_put_bitfield32(struct sk_buff *skb, int attrtype,
				     __u32 value, __u32 selector)
{
	struct nla_bitfield32 tmp = { value, selector, };

	return nla_put(skb, attrtype, sizeof(tmp), &tmp);
}

/**
 * nla_get_u32 - return payload of u32 attribute
 * @nla: u32 netlink attribute
 */
static inline u32 nla_get_u32(const struct nlattr *nla)
{
	return *(u32 *) nla_data(nla);
}

/**
 * nla_get_be32 - return payload of __be32 attribute
 * @nla: __be32 netlink attribute
 */
static inline __be32 nla_get_be32(const struct nlattr *nla)
{
	return *(__be32 *) nla_data(nla);
}

/**
 * nla_get_le32 - return payload of __le32 attribute
 * @nla: __le32 netlink attribute
 */
static inline __le32 nla_get_le32(const struct nlattr *nla)
{
	return *(__le32 *) nla_data(nla);
}

/**
 * nla_get_u16 - return payload of u16 attribute
 * @nla: u16 netlink attribute
 */
static inline u16 nla_get_u16(const struct nlattr *nla)
{
	return *(u16 *) nla_data(nla);
}

/**
 * nla_get_be16 - return payload of __be16 attribute
 * @nla: __be16 netlink attribute
 */
static inline __be16 nla_get_be16(const struct nlattr *nla)
{
	return *(__be16 *) nla_data(nla);
}

/**
 * nla_get_le16 - return payload of __le16 attribute
 * @nla: __le16 netlink attribute
 */
static inline __le16 nla_get_le16(const struct nlattr *nla)
{
	return *(__le16 *) nla_data(nla);
}

/**
 * nla_get_u8 - return payload of u8 attribute
 * @nla: u8 netlink attribute
 */
static inline u8 nla_get_u8(const struct nlattr *nla)
{
	return *(u8 *) nla_data(nla);
}

/**
 * nla_get_u64 - return payload of u64 attribute
 * @nla: u64 netlink attribute
 */
static inline u64 nla_get_u64(const struct nlattr *nla)
{
	u64 tmp;

	nla_memcpy(&tmp, nla, sizeof(tmp));

	return tmp;
}

/**
 * nla_get_be64 - return payload of __be64 attribute
 * @nla: __be64 netlink attribute
 */
static inline __be64 nla_get_be64(const struct nlattr *nla)
{
	__be64 tmp;

	nla_memcpy(&tmp, nla, sizeof(tmp));

	return tmp;
}

/**
 * nla_get_le64 - return payload of __le64 attribute
 * @nla: __le64 netlink attribute
 */
static inline __le64 nla_get_le64(const struct nlattr *nla)
{
	return *(__le64 *) nla_data(nla);
}

/**
 * nla_get_s32 - return payload of s32 attribute
 * @nla: s32 netlink attribute
 */
static inline s32 nla_get_s32(const struct nlattr *nla)
{
	return *(s32 *) nla_data(nla);
}

/**
 * nla_get_s16 - return payload of s16 attribute
 * @nla: s16 netlink attribute
 */
static inline s16 nla_get_s16(const struct nlattr *nla)
{
	return *(s16 *) nla_data(nla);
}

/**
 * nla_get_s8 - return payload of s8 attribute
 * @nla: s8 netlink attribute
 */
static inline s8 nla_get_s8(const struct nlattr *nla)
{
	return *(s8 *) nla_data(nla);
}

/**
 * nla_get_s64 - return payload of s64 attribute
 * @nla: s64 netlink attribute
 */
static inline s64 nla_get_s64(const struct nlattr *nla)
{
	s64 tmp;

	nla_memcpy(&tmp, nla, sizeof(tmp));

	return tmp;
}

/**
 * nla_get_flag - return payload of flag attribute
 * @nla: flag netlink attribute
 */
static inline int nla_get_flag(const struct nlattr *nla)
{
	return !!nla;
}

/**
 * nla_get_msecs - return payload of msecs attribute
 * @nla: msecs netlink attribute
 *
 * Returns the number of milliseconds in jiffies.
 */
static inline unsigned long nla_get_msecs(const struct nlattr *nla)
{
	u64 msecs = nla_get_u64(nla);

	return msecs_to_jiffies((unsigned long) msecs);
}

/**
 * nla_get_in_addr - return payload of IPv4 address attribute
 * @nla: IPv4 address netlink attribute
 */
static inline __be32 nla_get_in_addr(const struct nlattr *nla)
{
	return *(__be32 *) nla_data(nla);
}

/**
 * nla_get_in6_addr - return payload of IPv6 address attribute
 * @nla: IPv6 address netlink attribute
 */
static inline struct in6_addr nla_get_in6_addr(const struct nlattr *nla)
{
	struct in6_addr tmp;

	nla_memcpy(&tmp, nla, sizeof(tmp));
	return tmp;
}

/**
 * nla_get_bitfield32 - return payload of 32 bitfield attribute
 * @nla: nla_bitfield32 attribute
 */
static inline struct nla_bitfield32 nla_get_bitfield32(const struct nlattr *nla)
{
	struct nla_bitfield32 tmp;

	nla_memcpy(&tmp, nla, sizeof(tmp));
	return tmp;
}

/**
 * nla_memdup - duplicate attribute memory (kmemdup)
 * @src: netlink attribute to duplicate from
 * @gfp: GFP mask
 */
static inline void *nla_memdup(const struct nlattr *src, gfp_t gfp)
{
	return kmemdup(nla_data(src), nla_len(src), gfp);
}

/**
 * nla_nest_start_noflag - Start a new level of nested attributes
 * @skb: socket buffer to add attributes to
 * @attrtype: attribute type of container
 *
 * This function exists for backward compatibility to use in APIs which never
 * marked their nest attributes with NLA_F_NESTED flag. New APIs should use
 * nla_nest_start() which sets the flag.
 *
 * Returns the container attribute or NULL on error
 */
static inline struct nlattr *nla_nest_start_noflag(struct sk_buff *skb,
						   int attrtype)
{
	struct nlattr *start = (struct nlattr *)skb_tail_pointer(skb);

	if (nla_put(skb, attrtype, 0, NULL) < 0)
		return NULL;

	return start;
}

/**
 * nla_nest_start - Start a new level of nested attributes, with NLA_F_NESTED
 * @skb: socket buffer to add attributes to
 * @attrtype: attribute type of container
 *
 * Unlike nla_nest_start_noflag(), mark the nest attribute with NLA_F_NESTED
 * flag. This is the preferred function to use in new code.
 *
 * Returns the container attribute or NULL on error
 */
static inline struct nlattr *nla_nest_start(struct sk_buff *skb, int attrtype)
{
	return nla_nest_start_noflag(skb, attrtype | NLA_F_NESTED);
}

/**
 * nla_nest_end - Finalize nesting of attributes
 * @skb: socket buffer the attributes are stored in
 * @start: container attribute
 *
 * Corrects the container attribute header to include the all
 * appeneded attributes.
 *
 * Returns the total data length of the skb.
 */
static inline int nla_nest_end(struct sk_buff *skb, struct nlattr *start)
{
	start->nla_len = skb_tail_pointer(skb) - (unsigned char *)start;
	return skb->len;
}

/**
 * nla_nest_cancel - Cancel nesting of attributes
 * @skb: socket buffer the message is stored in
 * @start: container attribute
 *
 * Removes the container attribute and including all nested
 * attributes. Returns -EMSGSIZE
 */
static inline void nla_nest_cancel(struct sk_buff *skb, struct nlattr *start)
{
	nlmsg_trim(skb, start);
}

/**
 * __nla_validate_nested - Validate a stream of nested attributes
 * @start: container attribute
 * @maxtype: maximum attribute type to be expected
 * @policy: validation policy
 * @validate: validation strictness
 * @extack: extended ACK report struct
 *
 * Validates all attributes in the nested attribute stream against the
 * specified policy. Attributes with a type exceeding maxtype will be
 * ignored. See documenation of struct nla_policy for more details.
 *
 * Returns 0 on success or a negative error code.
 */
static inline int __nla_validate_nested(const struct nlattr *start, int maxtype,
					const struct nla_policy *policy,
					unsigned int validate,
					struct netlink_ext_ack *extack)
{
	return __nla_validate(nla_data(start), nla_len(start), maxtype, policy,
			      validate, extack);
}

static inline int
nla_validate_nested(const struct nlattr *start, int maxtype,
		    const struct nla_policy *policy,
		    struct netlink_ext_ack *extack)
{
	return __nla_validate_nested(start, maxtype, policy,
				     NL_VALIDATE_STRICT, extack);
}

static inline int
nla_validate_nested_deprecated(const struct nlattr *start, int maxtype,
			       const struct nla_policy *policy,
			       struct netlink_ext_ack *extack)
{
	return __nla_validate_nested(start, maxtype, policy,
				     NL_VALIDATE_LIBERAL, extack);
}

/**
 * nla_need_padding_for_64bit - test 64-bit alignment of the next attribute
 * @skb: socket buffer the message is stored in
 *
 * Return true if padding is needed to align the next attribute (nla_data()) to
 * a 64-bit aligned area.
 */
static inline bool nla_need_padding_for_64bit(struct sk_buff *skb)
{
#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
	/* The nlattr header is 4 bytes in size, that's why we test
	 * if the skb->data _is_ aligned.  A NOP attribute, plus
	 * nlattr header for next attribute, will make nla_data()
	 * 8-byte aligned.
	 */
	if (IS_ALIGNED((unsigned long)skb_tail_pointer(skb), 8))
		return true;
#endif
	return false;
}

/**
 * nla_align_64bit - 64-bit align the nla_data() of next attribute
 * @skb: socket buffer the message is stored in
 * @padattr: attribute type for the padding
 *
 * Conditionally emit a padding netlink attribute in order to make
 * the next attribute we emit have a 64-bit aligned nla_data() area.
 * This will only be done in architectures which do not have
 * CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS defined.
 *
 * Returns zero on success or a negative error code.
 */
static inline int nla_align_64bit(struct sk_buff *skb, int padattr)
{
	if (nla_need_padding_for_64bit(skb) &&
	    !nla_reserve(skb, padattr, 0))
		return -EMSGSIZE;

	return 0;
}

/**
 * nla_total_size_64bit - total length of attribute including padding
 * @payload: length of payload
 */
static inline int nla_total_size_64bit(int payload)
{
	return NLA_ALIGN(nla_attr_size(payload))
#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
		+ NLA_ALIGN(nla_attr_size(0))
#endif
		;
}

/**
 * nla_for_each_attr - iterate over a stream of attributes
 * @pos: loop counter, set to current attribute
 * @head: head of attribute stream
 * @len: length of attribute stream
 * @rem: initialized to len, holds bytes currently remaining in stream
 */
#define nla_for_each_attr(pos, head, len, rem) \
	for (pos = head, rem = len; \
	     nla_ok(pos, rem); \
	     pos = nla_next(pos, &(rem)))

/**
 * nla_for_each_nested - iterate over nested attributes
 * @pos: loop counter, set to current attribute
 * @nla: attribute containing the nested attributes
 * @rem: initialized to len, holds bytes currently remaining in stream
 */
#define nla_for_each_nested(pos, nla, rem) \
	nla_for_each_attr(pos, nla_data(nla), nla_len(nla), rem)

/**
 * nla_is_last - Test if attribute is last in stream
 * @nla: attribute to test
 * @rem: bytes remaining in stream
 */
static inline bool nla_is_last(const struct nlattr *nla, int rem)
{
	return nla->nla_len == rem;
}

void nla_get_range_unsigned(const struct nla_policy *pt,
			    struct netlink_range_validation *range);
void nla_get_range_signed(const struct nla_policy *pt,
			  struct netlink_range_validation_signed *range);

struct netlink_policy_dump_state;

int netlink_policy_dump_add_policy(struct netlink_policy_dump_state **pstate,
				   const struct nla_policy *policy,
				   unsigned int maxtype);
int netlink_policy_dump_get_policy_idx(struct netlink_policy_dump_state *state,
				       const struct nla_policy *policy,
				       unsigned int maxtype);
bool netlink_policy_dump_loop(struct netlink_policy_dump_state *state);
int netlink_policy_dump_write(struct sk_buff *skb,
			      struct netlink_policy_dump_state *state);
int netlink_policy_dump_attr_size_estimate(const struct nla_policy *pt);
int netlink_policy_dump_write_attr(struct sk_buff *skb,
				   const struct nla_policy *pt,
				   int nestattr);
void netlink_policy_dump_free(struct netlink_policy_dump_state *state);

#endif