summaryrefslogtreecommitdiffstats
path: root/net/sched/sch_api.c
blob: 0d99df1e764db812f5dfc78a9c54832c0f676f70 (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
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * net/sched/sch_api.c	Packet scheduler API.
 *
 * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
 *
 * Fixes:
 *
 * Rani Assaf <rani@magic.metawire.com> :980802: JIFFIES and CPU clock sources are repaired.
 * Eduardo J. Blanco <ejbs@netlabs.com.uy> :990222: kmod support
 * Jamal Hadi Salim <hadi@nortelnetworks.com>: 990601: ingress support
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/kmod.h>
#include <linux/list.h>
#include <linux/hrtimer.h>
#include <linux/slab.h>
#include <linux/hashtable.h>

#include <net/net_namespace.h>
#include <net/sock.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>
#include <net/pkt_cls.h>

/*

   Short review.
   -------------

   This file consists of two interrelated parts:

   1. queueing disciplines manager frontend.
   2. traffic classes manager frontend.

   Generally, queueing discipline ("qdisc") is a black box,
   which is able to enqueue packets and to dequeue them (when
   device is ready to send something) in order and at times
   determined by algorithm hidden in it.

   qdisc's are divided to two categories:
   - "queues", which have no internal structure visible from outside.
   - "schedulers", which split all the packets to "traffic classes",
     using "packet classifiers" (look at cls_api.c)

   In turn, classes may have child qdiscs (as rule, queues)
   attached to them etc. etc. etc.

   The goal of the routines in this file is to translate
   information supplied by user in the form of handles
   to more intelligible for kernel form, to make some sanity
   checks and part of work, which is common to all qdiscs
   and to provide rtnetlink notifications.

   All real intelligent work is done inside qdisc modules.



   Every discipline has two major routines: enqueue and dequeue.

   ---dequeue

   dequeue usually returns a skb to send. It is allowed to return NULL,
   but it does not mean that queue is empty, it just means that
   discipline does not want to send anything this time.
   Queue is really empty if q->q.qlen == 0.
   For complicated disciplines with multiple queues q->q is not
   real packet queue, but however q->q.qlen must be valid.

   ---enqueue

   enqueue returns 0, if packet was enqueued successfully.
   If packet (this one or another one) was dropped, it returns
   not zero error code.
   NET_XMIT_DROP 	- this packet dropped
     Expected action: do not backoff, but wait until queue will clear.
   NET_XMIT_CN	 	- probably this packet enqueued, but another one dropped.
     Expected action: backoff or ignore

   Auxiliary routines:

   ---peek

   like dequeue but without removing a packet from the queue

   ---reset

   returns qdisc to initial state: purge all buffers, clear all
   timers, counters (except for statistics) etc.

   ---init

   initializes newly created qdisc.

   ---destroy

   destroys resources allocated by init and during lifetime of qdisc.

   ---change

   changes qdisc parameters.
 */

/* Protects list of registered TC modules. It is pure SMP lock. */
static DEFINE_RWLOCK(qdisc_mod_lock);


/************************************************
 *	Queueing disciplines manipulation.	*
 ************************************************/


/* The list of all installed queueing disciplines. */

static struct Qdisc_ops *qdisc_base;

/* Register/unregister queueing discipline */

int register_qdisc(struct Qdisc_ops *qops)
{
	struct Qdisc_ops *q, **qp;
	int rc = -EEXIST;

	write_lock(&qdisc_mod_lock);
	for (qp = &qdisc_base; (q = *qp) != NULL; qp = &q->next)
		if (!strcmp(qops->id, q->id))
			goto out;

	if (qops->enqueue == NULL)
		qops->enqueue = noop_qdisc_ops.enqueue;
	if (qops->peek == NULL) {
		if (qops->dequeue == NULL)
			qops->peek = noop_qdisc_ops.peek;
		else
			goto out_einval;
	}
	if (qops->dequeue == NULL)
		qops->dequeue = noop_qdisc_ops.dequeue;

	if (qops->cl_ops) {
		const struct Qdisc_class_ops *cops = qops->cl_ops;

		if (!(cops->find && cops->walk && cops->leaf))
			goto out_einval;

		if (cops->tcf_block && !(cops->bind_tcf && cops->unbind_tcf))
			goto out_einval;
	}

	qops->next = NULL;
	*qp = qops;
	rc = 0;
out:
	write_unlock(&qdisc_mod_lock);
	return rc;

out_einval:
	rc = -EINVAL;
	goto out;
}
EXPORT_SYMBOL(register_qdisc);

int unregister_qdisc(struct Qdisc_ops *qops)
{
	struct Qdisc_ops *q, **qp;
	int err = -ENOENT;

	write_lock(&qdisc_mod_lock);
	for (qp = &qdisc_base; (q = *qp) != NULL; qp = &q->next)
		if (q == qops)
			break;
	if (q) {
		*qp = q->next;
		q->next = NULL;
		err = 0;
	}
	write_unlock(&qdisc_mod_lock);
	return err;
}
EXPORT_SYMBOL(unregister_qdisc);

/* Get default qdisc if not otherwise specified */
void qdisc_get_default(char *name, size_t len)
{
	read_lock(&qdisc_mod_lock);
	strlcpy(name, default_qdisc_ops->id, len);
	read_unlock(&qdisc_mod_lock);
}

static struct Qdisc_ops *qdisc_lookup_default(const char *name)
{
	struct Qdisc_ops *q = NULL;

	for (q = qdisc_base; q; q = q->next) {
		if (!strcmp(name, q->id)) {
			if (!try_module_get(q->owner))
				q = NULL;
			break;
		}
	}

	return q;
}

/* Set new default qdisc to use */
int qdisc_set_default(const char *name)
{
	const struct Qdisc_ops *ops;

	if (!capable(CAP_NET_ADMIN))
		return -EPERM;

	write_lock(&qdisc_mod_lock);
	ops = qdisc_lookup_default(name);
	if (!ops) {
		/* Not found, drop lock and try to load module */
		write_unlock(&qdisc_mod_lock);
		request_module("sch_%s", name);
		write_lock(&qdisc_mod_lock);

		ops = qdisc_lookup_default(name);
	}

	if (ops) {
		/* Set new default */
		module_put(default_qdisc_ops->owner);
		default_qdisc_ops = ops;
	}
	write_unlock(&qdisc_mod_lock);

	return ops ? 0 : -ENOENT;
}

#ifdef CONFIG_NET_SCH_DEFAULT
/* Set default value from kernel config */
static int __init sch_default_qdisc(void)
{
	return qdisc_set_default(CONFIG_DEFAULT_NET_SCH);
}
late_initcall(sch_default_qdisc);
#endif

/* We know handle. Find qdisc among all qdisc's attached to device
 * (root qdisc, all its children, children of children etc.)
 * Note: caller either uses rtnl or rcu_read_lock()
 */

static struct Qdisc *qdisc_match_from_root(struct Qdisc *root, u32 handle)
{
	struct Qdisc *q;

	if (!qdisc_dev(root))
		return (root->handle == handle ? root : NULL);

	if (!(root->flags & TCQ_F_BUILTIN) &&
	    root->handle == handle)
		return root;

	hash_for_each_possible_rcu(qdisc_dev(root)->qdisc_hash, q, hash, handle) {
		if (q->handle == handle)
			return q;
	}
	return NULL;
}

void qdisc_hash_add(struct Qdisc *q, bool invisible)
{
	if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS)) {
		ASSERT_RTNL();
		hash_add_rcu(qdisc_dev(q)->qdisc_hash, &q->hash, q->handle);
		if (invisible)
			q->flags |= TCQ_F_INVISIBLE;
	}
}
EXPORT_SYMBOL(qdisc_hash_add);

void qdisc_hash_del(struct Qdisc *q)
{
	if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS)) {
		ASSERT_RTNL();
		hash_del_rcu(&q->hash);
	}
}
EXPORT_SYMBOL(qdisc_hash_del);

struct Qdisc *qdisc_lookup(struct net_device *dev, u32 handle)
{
	struct Qdisc *q;

	if (!handle)
		return NULL;
	q = qdisc_match_from_root(dev->qdisc, handle);
	if (q)
		goto out;

	if (dev_ingress_queue(dev))
		q = qdisc_match_from_root(
			dev_ingress_queue(dev)->qdisc_sleeping,
			handle);
out:
	return q;
}

struct Qdisc *qdisc_lookup_rcu(struct net_device *dev, u32 handle)
{
	struct netdev_queue *nq;
	struct Qdisc *q;

	if (!handle)
		return NULL;
	q = qdisc_match_from_root(dev->qdisc, handle);
	if (q)
		goto out;

	nq = dev_ingress_queue_rcu(dev);
	if (nq)
		q = qdisc_match_from_root(nq->qdisc_sleeping, handle);
out:
	return q;
}

static struct Qdisc *qdisc_leaf(struct Qdisc *p, u32 classid)
{
	unsigned long cl;
	const struct Qdisc_class_ops *cops = p->ops->cl_ops;

	if (cops == NULL)
		return NULL;
	cl = cops->find(p, classid);

	if (cl == 0)
		return NULL;
	return cops->leaf(p, cl);
}

/* Find queueing discipline by name */

static struct Qdisc_ops *qdisc_lookup_ops(struct nlattr *kind)
{
	struct Qdisc_ops *q = NULL;

	if (kind) {
		read_lock(&qdisc_mod_lock);
		for (q = qdisc_base; q; q = q->next) {
			if (nla_strcmp(kind, q->id) == 0) {
				if (!try_module_get(q->owner))
					q = NULL;
				break;
			}
		}
		read_unlock(&qdisc_mod_lock);
	}
	return q;
}

/* The linklayer setting were not transferred from iproute2, in older
 * versions, and the rate tables lookup systems have been dropped in
 * the kernel. To keep backward compatible with older iproute2 tc
 * utils, we detect the linklayer setting by detecting if the rate
 * table were modified.
 *
 * For linklayer ATM table entries, the rate table will be aligned to
 * 48 bytes, thus some table entries will contain the same value.  The
 * mpu (min packet unit) is also encoded into the old rate table, thus
 * starting from the mpu, we find low and high table entries for
 * mapping this cell.  If these entries contain the same value, when
 * the rate tables have been modified for linklayer ATM.
 *
 * This is done by rounding mpu to the nearest 48 bytes cell/entry,
 * and then roundup to the next cell, calc the table entry one below,
 * and compare.
 */
static __u8 __detect_linklayer(struct tc_ratespec *r, __u32 *rtab)
{
	int low       = roundup(r->mpu, 48);
	int high      = roundup(low+1, 48);
	int cell_low  = low >> r->cell_log;
	int cell_high = (high >> r->cell_log) - 1;

	/* rtab is too inaccurate at rates > 100Mbit/s */
	if ((r->rate > (100000000/8)) || (rtab[0] == 0)) {
		pr_debug("TC linklayer: Giving up ATM detection\n");
		return TC_LINKLAYER_ETHERNET;
	}

	if ((cell_high > cell_low) && (cell_high < 256)
	    && (rtab[cell_low] == rtab[cell_high])) {
		pr_debug("TC linklayer: Detected ATM, low(%d)=high(%d)=%u\n",
			 cell_low, cell_high, rtab[cell_high]);
		return TC_LINKLAYER_ATM;
	}
	return TC_LINKLAYER_ETHERNET;
}

static struct qdisc_rate_table *qdisc_rtab_list;

struct qdisc_rate_table *qdisc_get_rtab(struct tc_ratespec *r,
					struct nlattr *tab,
					struct netlink_ext_ack *extack)
{
	struct qdisc_rate_table *rtab;

	if (tab == NULL || r->rate == 0 || r->cell_log == 0 ||
	    nla_len(tab) != TC_RTAB_SIZE) {
		NL_SET_ERR_MSG(extack, "Invalid rate table parameters for searching");
		return NULL;
	}

	for (rtab = qdisc_rtab_list; rtab; rtab = rtab->next) {
		if (!memcmp(&rtab->rate, r, sizeof(struct tc_ratespec)) &&
		    !memcmp(&rtab->data, nla_data(tab), 1024)) {
			rtab->refcnt++;
			return rtab;
		}
	}

	rtab = kmalloc(sizeof(*rtab), GFP_KERNEL);
	if (rtab) {
		rtab->rate = *r;
		rtab->refcnt = 1;
		memcpy(rtab->data, nla_data(tab), 1024);
		if (r->linklayer == TC_LINKLAYER_UNAWARE)
			r->linklayer = __detect_linklayer(r, rtab->data);
		rtab->next = qdisc_rtab_list;
		qdisc_rtab_list = rtab;
	} else {
		NL_SET_ERR_MSG(extack, "Failed to allocate new qdisc rate table");
	}
	return rtab;
}
EXPORT_SYMBOL(qdisc_get_rtab);

void qdisc_put_rtab(struct qdisc_rate_table *tab)
{
	struct qdisc_rate_table *rtab, **rtabp;

	if (!tab || --tab->refcnt)
		return;

	for (rtabp = &qdisc_rtab_list;
	     (rtab = *rtabp) != NULL;
	     rtabp = &rtab->next) {
		if (rtab == tab) {
			*rtabp = rtab->next;
			kfree(rtab);
			return;
		}
	}
}
EXPORT_SYMBOL(qdisc_put_rtab);

static LIST_HEAD(qdisc_stab_list);

static const struct nla_policy stab_policy[TCA_STAB_MAX + 1] = {
	[TCA_STAB_BASE]	= { .len = sizeof(struct tc_sizespec) },
	[TCA_STAB_DATA] = { .type = NLA_BINARY },
};

static struct qdisc_size_table *qdisc_get_stab(struct nlattr *opt,
					       struct netlink_ext_ack *extack)
{
	struct nlattr *tb[TCA_STAB_MAX + 1];
	struct qdisc_size_table *stab;
	struct tc_sizespec *s;
	unsigned int tsize = 0;
	u16 *tab = NULL;
	int err;

	err = nla_parse_nested_deprecated(tb, TCA_STAB_MAX, opt, stab_policy,
					  extack);
	if (err < 0)
		return ERR_PTR(err);
	if (!tb[TCA_STAB_BASE]) {
		NL_SET_ERR_MSG(extack, "Size table base attribute is missing");
		return ERR_PTR(-EINVAL);
	}

	s = nla_data(tb[TCA_STAB_BASE]);

	if (s->tsize > 0) {
		if (!tb[TCA_STAB_DATA]) {
			NL_SET_ERR_MSG(extack, "Size table data attribute is missing");
			return ERR_PTR(-EINVAL);
		}
		tab = nla_data(tb[TCA_STAB_DATA]);
		tsize = nla_len(tb[TCA_STAB_DATA]) / sizeof(u16);
	}

	if (tsize != s->tsize || (!tab && tsize > 0)) {
		NL_SET_ERR_MSG(extack, "Invalid size of size table");
		return ERR_PTR(-EINVAL);
	}

	list_for_each_entry(stab, &qdisc_stab_list, list) {
		if (memcmp(&stab->szopts, s, sizeof(*s)))
			continue;
		if (tsize > 0 && memcmp(stab->data, tab, tsize * sizeof(u16)))
			continue;
		stab->refcnt++;
		return stab;
	}

	stab = kmalloc(sizeof(*stab) + tsize * sizeof(u16), GFP_KERNEL);
	if (!stab)
		return ERR_PTR(-ENOMEM);

	stab->refcnt = 1;
	stab->szopts = *s;
	if (tsize > 0)
		memcpy(stab->data, tab, tsize * sizeof(u16));

	list_add_tail(&stab->list, &qdisc_stab_list);

	return stab;
}

void qdisc_put_stab(struct qdisc_size_table *tab)
{
	if (!tab)
		return;

	if (--tab->refcnt == 0) {
		list_del(&tab->list);
		kfree_rcu(tab, rcu);
	}
}
EXPORT_SYMBOL(qdisc_put_stab);

static int qdisc_dump_stab(struct sk_buff *skb, struct qdisc_size_table *stab)
{
	struct nlattr *nest;

	nest = nla_nest_start_noflag(skb, TCA_STAB);
	if (nest == NULL)
		goto nla_put_failure;
	if (nla_put(skb, TCA_STAB_BASE, sizeof(stab->szopts), &stab->szopts))
		goto nla_put_failure;
	nla_nest_end(skb, nest);

	return skb->len;

nla_put_failure:
	return -1;
}

void __qdisc_calculate_pkt_len(struct sk_buff *skb,
			       const struct qdisc_size_table *stab)
{
	int pkt_len, slot;

	pkt_len = skb->len + stab->szopts.overhead;
	if (unlikely(!stab->szopts.tsize))
		goto out;

	slot = pkt_len + stab->szopts.cell_align;
	if (unlikely(slot < 0))
		slot = 0;

	slot >>= stab->szopts.cell_log;
	if (likely(slot < stab->szopts.tsize))
		pkt_len = stab->data[slot];
	else
		pkt_len = stab->data[stab->szopts.tsize - 1] *
				(slot / stab->szopts.tsize) +
				stab->data[slot % stab->szopts.tsize];

	pkt_len <<= stab->szopts.size_log;
out:
	if (unlikely(pkt_len < 1))
		pkt_len = 1;
	qdisc_skb_cb(skb)->pkt_len = pkt_len;
}
EXPORT_SYMBOL(__qdisc_calculate_pkt_len);

void qdisc_warn_nonwc(const char *txt, struct Qdisc *qdisc)
{
	if (!(qdisc->flags & TCQ_F_WARN_NONWC)) {
		pr_warn("%s: %s qdisc %X: is non-work-conserving?\n",
			txt, qdisc->ops->id, qdisc->handle >> 16);
		qdisc->flags |= TCQ_F_WARN_NONWC;
	}
}
EXPORT_SYMBOL(qdisc_warn_nonwc);

static enum hrtimer_restart qdisc_watchdog(struct hrtimer *timer)
{
	struct qdisc_watchdog *wd = container_of(timer, struct qdisc_watchdog,
						 timer);

	rcu_read_lock();
	__netif_schedule(qdisc_root(wd->qdisc));
	rcu_read_unlock();

	return HRTIMER_NORESTART;
}

void qdisc_watchdog_init_clockid(struct qdisc_watchdog *wd, struct Qdisc *qdisc,
				 clockid_t clockid)
{
	hrtimer_init(&wd->timer, clockid, HRTIMER_MODE_ABS_PINNED);
	wd->timer.function = qdisc_watchdog;
	wd->qdisc = qdisc;
}
EXPORT_SYMBOL(qdisc_watchdog_init_clockid);

void qdisc_watchdog_init(struct qdisc_watchdog *wd, struct Qdisc *qdisc)
{
	qdisc_watchdog_init_clockid(wd, qdisc, CLOCK_MONOTONIC);
}
EXPORT_SYMBOL(qdisc_watchdog_init);

void qdisc_watchdog_schedule_range_ns(struct qdisc_watchdog *wd, u64 expires,
				      u64 delta_ns)
{
	if (test_bit(__QDISC_STATE_DEACTIVATED,
		     &qdisc_root_sleeping(wd->qdisc)->state))
		return;

	if (hrtimer_is_queued(&wd->timer)) {
		/* If timer is already set in [expires, expires + delta_ns],
		 * do not reprogram it.
		 */
		if (wd->last_expires - expires <= delta_ns)
			return;
	}

	wd->last_expires = expires;
	hrtimer_start_range_ns(&wd->timer,
			       ns_to_ktime(expires),
			       delta_ns,
			       HRTIMER_MODE_ABS_PINNED);
}
EXPORT_SYMBOL(qdisc_watchdog_schedule_range_ns);

void qdisc_watchdog_cancel(struct qdisc_watchdog *wd)
{
	hrtimer_cancel(&wd->timer);
}
EXPORT_SYMBOL(qdisc_watchdog_cancel);

static struct hlist_head *qdisc_class_hash_alloc(unsigned int n)
{
	struct hlist_head *h;
	unsigned int i;

	h = kvmalloc_array(n, sizeof(struct hlist_head), GFP_KERNEL);

	if (h != NULL) {
		for (i = 0; i < n; i++)
			INIT_HLIST_HEAD(&h[i]);
	}
	return h;
}

void qdisc_class_hash_grow(struct Qdisc *sch, struct Qdisc_class_hash *clhash)
{
	struct Qdisc_class_common *cl;
	struct hlist_node *next;
	struct hlist_head *nhash, *ohash;
	unsigned int nsize, nmask, osize;
	unsigned int i, h;

	/* Rehash when load factor exceeds 0.75 */
	if (clhash->hashelems * 4 <= clhash->hashsize * 3)
		return;
	nsize = clhash->hashsize * 2;
	nmask = nsize - 1;
	nhash = qdisc_class_hash_alloc(nsize);
	if (nhash == NULL)
		return;

	ohash = clhash->hash;
	osize = clhash->hashsize;

	sch_tree_lock(sch);
	for (i = 0; i < osize; i++) {
		hlist_for_each_entry_safe(cl, next, &ohash[i], hnode) {
			h = qdisc_class_hash(cl->classid, nmask);
			hlist_add_head(&cl->hnode, &nhash[h]);
		}
	}
	clhash->hash     = nhash;
	clhash->hashsize = nsize;
	clhash->hashmask = nmask;
	sch_tree_unlock(sch);

	kvfree(ohash);
}
EXPORT_SYMBOL(qdisc_class_hash_grow);

int qdisc_class_hash_init(struct Qdisc_class_hash *clhash)
{
	unsigned int size = 4;

	clhash->hash = qdisc_class_hash_alloc(size);
	if (!clhash->hash)
		return -ENOMEM;
	clhash->hashsize  = size;
	clhash->hashmask  = size - 1;
	clhash->hashelems = 0;
	return 0;
}
EXPORT_SYMBOL(qdisc_class_hash_init);

void qdisc_class_hash_destroy(struct Qdisc_class_hash *clhash)
{
	kvfree(clhash->hash);
}
EXPORT_SYMBOL(qdisc_class_hash_destroy);

void qdisc_class_hash_insert(struct Qdisc_class_hash *clhash,
			     struct Qdisc_class_common *cl)
{
	unsigned int h;

	INIT_HLIST_NODE(&cl->hnode);
	h = qdisc_class_hash(cl->classid, clhash->hashmask);
	hlist_add_head(&cl->hnode, &clhash->hash[h]);
	clhash->hashelems++;
}
EXPORT_SYMBOL(qdisc_class_hash_insert);

void qdisc_class_hash_remove(struct Qdisc_class_hash *clhash,
			     struct Qdisc_class_common *cl)
{
	hlist_del(&cl->hnode);
	clhash->hashelems--;
}
EXPORT_SYMBOL(qdisc_class_hash_remove);

/* Allocate an unique handle from space managed by kernel
 * Possible range is [8000-FFFF]:0000 (0x8000 values)
 */
static u32 qdisc_alloc_handle(struct net_device *dev)
{
	int i = 0x8000;
	static u32 autohandle = TC_H_MAKE(0x80000000U, 0);

	do {
		autohandle += TC_H_MAKE(0x10000U, 0);
		if (autohandle == TC_H_MAKE(TC_H_ROOT, 0))
			autohandle = TC_H_MAKE(0x80000000U, 0);
		if (!qdisc_lookup(dev, autohandle))
			return autohandle;
		cond_resched();
	} while	(--i > 0);

	return 0;
}

void qdisc_tree_reduce_backlog(struct Qdisc *sch, int n, int len)
{
	bool qdisc_is_offloaded = sch->flags & TCQ_F_OFFLOADED;
	const struct Qdisc_class_ops *cops;
	unsigned long cl;
	u32 parentid;
	bool notify;
	int drops;

	if (n == 0 && len == 0)
		return;
	drops = max_t(int, n, 0);
	rcu_read_lock();
	while ((parentid = sch->parent)) {
		if (TC_H_MAJ(parentid) == TC_H_MAJ(TC_H_INGRESS))
			break;

		if (sch->flags & TCQ_F_NOPARENT)
			break;
		/* Notify parent qdisc only if child qdisc becomes empty.
		 *
		 * If child was empty even before update then backlog
		 * counter is screwed and we skip notification because
		 * parent class is already passive.
		 *
		 * If the original child was offloaded then it is allowed
		 * to be seem as empty, so the parent is notified anyway.
		 */
		notify = !sch->q.qlen && !WARN_ON_ONCE(!n &&
						       !qdisc_is_offloaded);
		/* TODO: perform the search on a per txq basis */
		sch = qdisc_lookup(qdisc_dev(sch), TC_H_MAJ(parentid));
		if (sch == NULL) {
			WARN_ON_ONCE(parentid != TC_H_ROOT);
			break;
		}
		cops = sch->ops->cl_ops;
		if (notify && cops->qlen_notify) {
			cl = cops->find(sch, parentid);
			cops->qlen_notify(sch, cl);
		}
		sch->q.qlen -= n;
		sch->qstats.backlog -= len;
		__qdisc_qstats_drop(sch, drops);
	}
	rcu_read_unlock();
}
EXPORT_SYMBOL(qdisc_tree_reduce_backlog);

int qdisc_offload_dump_helper(struct Qdisc *sch, enum tc_setup_type type,
			      void *type_data)
{
	struct net_device *dev = qdisc_dev(sch);
	int err;

	sch->flags &= ~TCQ_F_OFFLOADED;
	if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
		return 0;

	err = dev->netdev_ops->ndo_setup_tc(dev, type, type_data);
	if (err == -EOPNOTSUPP)
		return 0;

	if (!err)
		sch->flags |= TCQ_F_OFFLOADED;

	return err;
}
EXPORT_SYMBOL(qdisc_offload_dump_helper);

void qdisc_offload_graft_helper(struct net_device *dev, struct Qdisc *sch,
				struct Qdisc *new, struct Qdisc *old,
				enum tc_setup_type type, void *type_data,
				struct netlink_ext_ack *extack)
{
	bool any_qdisc_is_offloaded;
	int err;

	if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
		return;

	err = dev->netdev_ops->ndo_setup_tc(dev, type, type_data);

	/* Don't report error if the graft is part of destroy operation. */
	if (!err || !new || new == &noop_qdisc)
		return;

	/* Don't report error if the parent, the old child and the new
	 * one are not offloaded.
	 */
	any_qdisc_is_offloaded = new->flags & TCQ_F_OFFLOADED;
	any_qdisc_is_offloaded |= sch && sch->flags & TCQ_F_OFFLOADED;
	any_qdisc_is_offloaded |= old && old->flags & TCQ_F_OFFLOADED;

	if (any_qdisc_is_offloaded)
		NL_SET_ERR_MSG(extack, "Offloading graft operation failed.");
}
EXPORT_SYMBOL(qdisc_offload_graft_helper);

static void qdisc_offload_graft_root(struct net_device *dev,
				     struct Qdisc *new, struct Qdisc *old,
				     struct netlink_ext_ack *extack)
{
	struct tc_root_qopt_offload graft_offload = {
		.command	= TC_ROOT_GRAFT,
		.handle		= new ? new->handle : 0,
		.ingress	= (new && new->flags & TCQ_F_INGRESS) ||
				  (old && old->flags & TCQ_F_INGRESS),
	};

	qdisc_offload_graft_helper(dev, NULL, new, old,
				   TC_SETUP_ROOT_QDISC, &graft_offload, extack);
}

static int tc_fill_qdisc(struct sk_buff *skb, struct Qdisc *q, u32 clid,
			 u32 portid, u32 seq, u16 flags, int event)
{
	struct gnet_stats_basic_cpu __percpu *cpu_bstats = NULL;
	struct gnet_stats_queue __percpu *cpu_qstats = NULL;
	struct tcmsg *tcm;
	struct nlmsghdr  *nlh;
	unsigned char *b = skb_tail_pointer(skb);
	struct gnet_dump d;
	struct qdisc_size_table *stab;
	u32 block_index;
	__u32 qlen;

	cond_resched();
	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*tcm), flags);
	if (!nlh)
		goto out_nlmsg_trim;
	tcm = nlmsg_data(nlh);
	tcm->tcm_family = AF_UNSPEC;
	tcm->tcm__pad1 = 0;
	tcm->tcm__pad2 = 0;
	tcm->tcm_ifindex = qdisc_dev(q)->ifindex;
	tcm->tcm_parent = clid;
	tcm->tcm_handle = q->handle;
	tcm->tcm_info = refcount_read(&q->refcnt);
	if (nla_put_string(skb, TCA_KIND, q->ops->id))
		goto nla_put_failure;
	if (q->ops->ingress_block_get) {
		block_index = q->ops->ingress_block_get(q);
		if (block_index &&
		    nla_put_u32(skb, TCA_INGRESS_BLOCK, block_index))
			goto nla_put_failure;
	}
	if (q->ops->egress_block_get) {
		block_index = q->ops->egress_block_get(q);
		if (block_index &&
		    nla_put_u32(skb, TCA_EGRESS_BLOCK, block_index))
			goto nla_put_failure;
	}
	if (q->ops->dump && q->ops->dump(q, skb) < 0)
		goto nla_put_failure;
	if (nla_put_u8(skb, TCA_HW_OFFLOAD, !!(q->flags & TCQ_F_OFFLOADED)))
		goto nla_put_failure;
	qlen = qdisc_qlen_sum(q);

	stab = rtnl_dereference(q->stab);
	if (stab && qdisc_dump_stab(skb, stab) < 0)
		goto nla_put_failure;

	if (gnet_stats_start_copy_compat(skb, TCA_STATS2, TCA_STATS, TCA_XSTATS,
					 NULL, &d, TCA_PAD) < 0)
		goto nla_put_failure;

	if (q->ops->dump_stats && q->ops->dump_stats(q, &d) < 0)
		goto nla_put_failure;

	if (qdisc_is_percpu_stats(q)) {
		cpu_bstats = q->cpu_bstats;
		cpu_qstats = q->cpu_qstats;
	}

	if (gnet_stats_copy_basic(qdisc_root_sleeping_running(q),
				  &d, cpu_bstats, &q->bstats) < 0 ||
	    gnet_stats_copy_rate_est(&d, &q->rate_est) < 0 ||
	    gnet_stats_copy_queue(&d, cpu_qstats, &q->qstats, qlen) < 0)
		goto nla_put_failure;

	if (gnet_stats_finish_copy(&d) < 0)
		goto nla_put_failure;

	nlh->nlmsg_len = skb_tail_pointer(skb) - b;
	return skb->len;

out_nlmsg_trim:
nla_put_failure:
	nlmsg_trim(skb, b);
	return -1;
}

static bool tc_qdisc_dump_ignore(struct Qdisc *q, bool dump_invisible)
{
	if (q->flags & TCQ_F_BUILTIN)
		return true;
	if ((q->flags & TCQ_F_INVISIBLE) && !dump_invisible)
		return true;

	return false;
}

static int qdisc_notify(struct net *net, struct sk_buff *oskb,
			struct nlmsghdr *n, u32 clid,
			struct Qdisc *old, struct Qdisc *new)
{
	struct sk_buff *skb;
	u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;

	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
	if (!skb)
		return -ENOBUFS;

	if (old && !tc_qdisc_dump_ignore(old, false)) {
		if (tc_fill_qdisc(skb, old, clid, portid, n->nlmsg_seq,
				  0, RTM_DELQDISC) < 0)
			goto err_out;
	}
	if (new && !tc_qdisc_dump_ignore(new, false)) {
		if (tc_fill_qdisc(skb, new, clid, portid, n->nlmsg_seq,
				  old ? NLM_F_REPLACE : 0, RTM_NEWQDISC) < 0)
			goto err_out;
	}

	if (skb->len)
		return rtnetlink_send(skb, net, portid, RTNLGRP_TC,
				      n->nlmsg_flags & NLM_F_ECHO);

err_out:
	kfree_skb(skb);
	return -EINVAL;
}

static void notify_and_destroy(struct net *net, struct sk_buff *skb,
			       struct nlmsghdr *n, u32 clid,
			       struct Qdisc *old, struct Qdisc *new)
{
	if (new || old)
		qdisc_notify(net, skb, n, clid, old, new);

	if (old)
		qdisc_put(old);
}

static void qdisc_clear_nolock(struct Qdisc *sch)
{
	sch->flags &= ~TCQ_F_NOLOCK;
	if (!(sch->flags & TCQ_F_CPUSTATS))
		return;

	free_percpu(sch->cpu_bstats);
	free_percpu(sch->cpu_qstats);
	sch->cpu_bstats = NULL;
	sch->cpu_qstats = NULL;
	sch->flags &= ~TCQ_F_CPUSTATS;
}

/* Graft qdisc "new" to class "classid" of qdisc "parent" or
 * to device "dev".
 *
 * When appropriate send a netlink notification using 'skb'
 * and "n".
 *
 * On success, destroy old qdisc.
 */

static int qdisc_graft(struct net_device *dev, struct Qdisc *parent,
		       struct sk_buff *skb, struct nlmsghdr *n, u32 classid,
		       struct Qdisc *new, struct Qdisc *old,
		       struct netlink_ext_ack *extack)
{
	struct Qdisc *q = old;
	struct net *net = dev_net(dev);

	if (parent == NULL) {
		unsigned int i, num_q, ingress;

		ingress = 0;
		num_q = dev->num_tx_queues;
		if ((q && q->flags & TCQ_F_INGRESS) ||
		    (new && new->flags & TCQ_F_INGRESS)) {
			num_q = 1;
			ingress = 1;
			if (!dev_ingress_queue(dev)) {
				NL_SET_ERR_MSG(extack, "Device does not have an ingress queue");
				return -ENOENT;
			}
		}

		if (dev->flags & IFF_UP)
			dev_deactivate(dev);

		qdisc_offload_graft_root(dev, new, old, extack);

		if (new && new->ops->attach)
			goto skip;

		for (i = 0; i < num_q; i++) {
			struct netdev_queue *dev_queue = dev_ingress_queue(dev);

			if (!ingress)
				dev_queue = netdev_get_tx_queue(dev, i);

			old = dev_graft_qdisc(dev_queue, new);
			if (new && i > 0)
				qdisc_refcount_inc(new);

			if (!ingress)
				qdisc_put(old);
		}

skip:
		if (!ingress) {
			notify_and_destroy(net, skb, n, classid,
					   dev->qdisc, new);
			if (new && !new->ops->attach)
				qdisc_refcount_inc(new);
			dev->qdisc = new ? : &noop_qdisc;

			if (new && new->ops->attach)
				new->ops->attach(new);
		} else {
			notify_and_destroy(net, skb, n, classid, old, new);
		}

		if (dev->flags & IFF_UP)
			dev_activate(dev);
	} else {
		const struct Qdisc_class_ops *cops = parent->ops->cl_ops;
		unsigned long cl;
		int err;

		/* Only support running class lockless if parent is lockless */
		if (new && (new->flags & TCQ_F_NOLOCK) &&
		    parent && !(parent->flags & TCQ_F_NOLOCK))
			qdisc_clear_nolock(new);

		if (!cops || !cops->graft)
			return -EOPNOTSUPP;

		cl = cops->find(parent, classid);
		if (!cl) {
			NL_SET_ERR_MSG(extack, "Specified class not found");
			return -ENOENT;
		}

		err = cops->graft(parent, cl, new, &old, extack);
		if (err)
			return err;
		notify_and_destroy(net, skb, n, classid, old, new);
	}
	return 0;
}

static int qdisc_block_indexes_set(struct Qdisc *sch, struct nlattr **tca,
				   struct netlink_ext_ack *extack)
{
	u32 block_index;

	if (tca[TCA_INGRESS_BLOCK]) {
		block_index = nla_get_u32(tca[TCA_INGRESS_BLOCK]);

		if (!block_index) {
			NL_SET_ERR_MSG(extack, "Ingress block index cannot be 0");
			return -EINVAL;
		}
		if (!sch->ops->ingress_block_set) {
			NL_SET_ERR_MSG(extack, "Ingress block sharing is not supported");
			return -EOPNOTSUPP;
		}
		sch->ops->ingress_block_set(sch, block_index);
	}
	if (tca[TCA_EGRESS_BLOCK]) {
		block_index = nla_get_u32(tca[TCA_EGRESS_BLOCK]);

		if (!block_index) {
			NL_SET_ERR_MSG(extack, "Egress block index cannot be 0");
			return -EINVAL;
		}
		if (!sch->ops->egress_block_set) {
			NL_SET_ERR_MSG(extack, "Egress block sharing is not supported");
			return -EOPNOTSUPP;
		}
		sch->ops->egress_block_set(sch, block_index);
	}
	return 0;
}

/*
   Allocate and initialize new qdisc.

   Parameters are passed via opt.
 */

static struct Qdisc *qdisc_create(struct net_device *dev,
				  struct netdev_queue *dev_queue,
				  struct Qdisc *p, u32 parent, u32 handle,
				  struct nlattr **tca, int *errp,
				  struct netlink_ext_ack *extack)
{
	int err;
	struct nlattr *kind = tca[TCA_KIND];
	struct Qdisc *sch;
	struct Qdisc_ops *ops;
	struct qdisc_size_table *stab;

	ops = qdisc_lookup_ops(kind);
#ifdef CONFIG_MODULES
	if (ops == NULL && kind != NULL) {
		char name[IFNAMSIZ];
		if (nla_strlcpy(name, kind, IFNAMSIZ) < IFNAMSIZ) {
			/* We dropped the RTNL semaphore in order to
			 * perform the module load.  So, even if we
			 * succeeded in loading the module we have to
			 * tell the caller to replay the request.  We
			 * indicate this using -EAGAIN.
			 * We replay the request because the device may
			 * go away in the mean time.
			 */
			rtnl_unlock();
			request_module("sch_%s", name);
			rtnl_lock();
			ops = qdisc_lookup_ops(kind);
			if (ops != NULL) {
				/* We will try again qdisc_lookup_ops,
				 * so don't keep a reference.
				 */
				module_put(ops->owner);
				err = -EAGAIN;
				goto err_out;
			}
		}
	}
#endif

	err = -ENOENT;
	if (!ops) {
		NL_SET_ERR_MSG(extack, "Specified qdisc not found");
		goto err_out;
	}

	sch = qdisc_alloc(dev_queue, ops, extack);
	if (IS_ERR(sch)) {
		err = PTR_ERR(sch);
		goto err_out2;
	}

	sch->parent = parent;

	if (handle == TC_H_INGRESS) {
		sch->flags |= TCQ_F_INGRESS;
		handle = TC_H_MAKE(TC_H_INGRESS, 0);
	} else {
		if (handle == 0) {
			handle = qdisc_alloc_handle(dev);
			if (handle == 0) {
				NL_SET_ERR_MSG(extack, "Maximum number of qdisc handles was exceeded");
				err = -ENOSPC;
				goto err_out3;
			}
		}
		if (!netif_is_multiqueue(dev))
			sch->flags |= TCQ_F_ONETXQUEUE;
	}

	sch->handle = handle;

	/* This exist to keep backward compatible with a userspace
	 * loophole, what allowed userspace to get IFF_NO_QUEUE
	 * facility on older kernels by setting tx_queue_len=0 (prior
	 * to qdisc init), and then forgot to reinit tx_queue_len
	 * before again attaching a qdisc.
	 */
	if ((dev->priv_flags & IFF_NO_QUEUE) && (dev->tx_queue_len == 0)) {
		dev->tx_queue_len = DEFAULT_TX_QUEUE_LEN;
		netdev_info(dev, "Caught tx_queue_len zero misconfig\n");
	}

	err = qdisc_block_indexes_set(sch, tca, extack);
	if (err)
		goto err_out3;

	if (ops->init) {
		err = ops->init(sch, tca[TCA_OPTIONS], extack);
		if (err != 0)
			goto err_out5;
	}

	if (tca[TCA_STAB]) {
		stab = qdisc_get_stab(tca[TCA_STAB], extack);
		if (IS_ERR(stab)) {
			err = PTR_ERR(stab);
			goto err_out4;
		}
		rcu_assign_pointer(sch->stab, stab);
	}
	if (tca[TCA_RATE]) {
		seqcount_t *running;

		err = -EOPNOTSUPP;
		if (sch->flags & TCQ_F_MQROOT) {
			NL_SET_ERR_MSG(extack, "Cannot attach rate estimator to a multi-queue root qdisc");
			goto err_out4;
		}

		if (sch->parent != TC_H_ROOT &&
		    !(sch->flags & TCQ_F_INGRESS) &&
		    (!p || !(p->flags & TCQ_F_MQROOT)))
			running = qdisc_root_sleeping_running(sch);
		else
			running = &sch->running;

		err = gen_new_estimator(&sch->bstats,
					sch->cpu_bstats,
					&sch->rate_est,
					NULL,
					running,
					tca[TCA_RATE]);
		if (err) {
			NL_SET_ERR_MSG(extack, "Failed to generate new estimator");
			goto err_out4;
		}
	}

	qdisc_hash_add(sch, false);

	return sch;

err_out5:
	/* ops->init() failed, we call ->destroy() like qdisc_create_dflt() */
	if (ops->destroy)
		ops->destroy(sch);
err_out3:
	dev_put(dev);
	qdisc_free(sch);
err_out2:
	module_put(ops->owner);
err_out:
	*errp = err;
	return NULL;

err_out4:
	/*
	 * Any broken qdiscs that would require a ops->reset() here?
	 * The qdisc was never in action so it shouldn't be necessary.
	 */
	qdisc_put_stab(rtnl_dereference(sch->stab));
	if (ops->destroy)
		ops->destroy(sch);
	goto err_out3;
}

static int qdisc_change(struct Qdisc *sch, struct nlattr **tca,
			struct netlink_ext_ack *extack)
{
	struct qdisc_size_table *ostab, *stab = NULL;
	int err = 0;

	if (tca[TCA_OPTIONS]) {
		if (!sch->ops->change) {
			NL_SET_ERR_MSG(extack, "Change operation not supported by specified qdisc");
			return -EINVAL;
		}
		if (tca[TCA_INGRESS_BLOCK] || tca[TCA_EGRESS_BLOCK]) {
			NL_SET_ERR_MSG(extack, "Change of blocks is not supported");
			return -EOPNOTSUPP;
		}
		err = sch->ops->change(sch, tca[TCA_OPTIONS], extack);
		if (err)
			return err;
	}

	if (tca[TCA_STAB]) {
		stab = qdisc_get_stab(tca[TCA_STAB], extack);
		if (IS_ERR(stab))
			return PTR_ERR(stab);
	}

	ostab = rtnl_dereference(sch->stab);
	rcu_assign_pointer(sch->stab, stab);
	qdisc_put_stab(ostab);

	if (tca[TCA_RATE]) {
		/* NB: ignores errors from replace_estimator
		   because change can't be undone. */
		if (sch->flags & TCQ_F_MQROOT)
			goto out;
		gen_replace_estimator(&sch->bstats,
				      sch->cpu_bstats,
				      &sch->rate_est,
				      NULL,
				      qdisc_root_sleeping_running(sch),
				      tca[TCA_RATE]);
	}
out:
	return 0;
}

struct check_loop_arg {
	struct qdisc_walker	w;
	struct Qdisc		*p;
	int			depth;
};

static int check_loop_fn(struct Qdisc *q, unsigned long cl,
			 struct qdisc_walker *w);

static int check_loop(struct Qdisc *q, struct Qdisc *p, int depth)
{
	struct check_loop_arg	arg;

	if (q->ops->cl_ops == NULL)
		return 0;

	arg.w.stop = arg.w.skip = arg.w.count = 0;
	arg.w.fn = check_loop_fn;
	arg.depth = depth;
	arg.p = p;
	q->ops->cl_ops->walk(q, &arg.w);
	return arg.w.stop ? -ELOOP : 0;
}

static int
check_loop_fn(struct Qdisc *q, unsigned long cl, struct qdisc_walker *w)
{
	struct Qdisc *leaf;
	const struct Qdisc_class_ops *cops = q->ops->cl_ops;
	struct check_loop_arg *arg = (struct check_loop_arg *)w;

	leaf = cops->leaf(q, cl);
	if (leaf) {
		if (leaf == arg->p || arg->depth > 7)
			return -ELOOP;
		return check_loop(leaf, arg->p, arg->depth + 1);
	}
	return 0;
}

const struct nla_policy rtm_tca_policy[TCA_MAX + 1] = {
	[TCA_KIND]		= { .type = NLA_STRING },
	[TCA_RATE]		= { .type = NLA_BINARY,
				    .len = sizeof(struct tc_estimator) },
	[TCA_STAB]		= { .type = NLA_NESTED },
	[TCA_DUMP_INVISIBLE]	= { .type = NLA_FLAG },
	[TCA_CHAIN]		= { .type = NLA_U32 },
	[TCA_INGRESS_BLOCK]	= { .type = NLA_U32 },
	[TCA_EGRESS_BLOCK]	= { .type = NLA_U32 },
};

/*
 * Delete/get qdisc.
 */

static int tc_get_qdisc(struct sk_buff *skb, struct nlmsghdr *n,
			struct netlink_ext_ack *extack)
{
	struct net *net = sock_net(skb->sk);
	struct tcmsg *tcm = nlmsg_data(n);
	struct nlattr *tca[TCA_MAX + 1];
	struct net_device *dev;
	u32 clid;
	struct Qdisc *q = NULL;
	struct Qdisc *p = NULL;
	int err;

	if ((n->nlmsg_type != RTM_GETQDISC) &&
	    !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
		return -EPERM;

	err = nlmsg_parse_deprecated(n, sizeof(*tcm), tca, TCA_MAX,
				     rtm_tca_policy, extack);
	if (err < 0)
		return err;

	dev = __dev_get_by_index(net, tcm->tcm_ifindex);
	if (!dev)
		return -ENODEV;

	clid = tcm->tcm_parent;
	if (clid) {
		if (clid != TC_H_ROOT) {
			if (TC_H_MAJ(clid) != TC_H_MAJ(TC_H_INGRESS)) {
				p = qdisc_lookup(dev, TC_H_MAJ(clid));
				if (!p) {
					NL_SET_ERR_MSG(extack, "Failed to find qdisc with specified classid");
					return -ENOENT;
				}
				q = qdisc_leaf(p, clid);
			} else if (dev_ingress_queue(dev)) {
				q = dev_ingress_queue(dev)->qdisc_sleeping;
			}
		} else {
			q = dev->qdisc;
		}
		if (!q) {
			NL_SET_ERR_MSG(extack, "Cannot find specified qdisc on specified device");
			return -ENOENT;
		}

		if (tcm->tcm_handle && q->handle != tcm->tcm_handle) {
			NL_SET_ERR_MSG(extack, "Invalid handle");
			return -EINVAL;
		}
	} else {
		q = qdisc_lookup(dev, tcm->tcm_handle);
		if (!q) {
			NL_SET_ERR_MSG(extack, "Failed to find qdisc with specified handle");
			return -ENOENT;
		}
	}

	if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], q->ops->id)) {
		NL_SET_ERR_MSG(extack, "Invalid qdisc name");
		return -EINVAL;
	}

	if (n->nlmsg_type == RTM_DELQDISC) {
		if (!clid) {
			NL_SET_ERR_MSG(extack, "Classid cannot be zero");
			return -EINVAL;
		}
		if (q->handle == 0) {
			NL_SET_ERR_MSG(extack, "Cannot delete qdisc with handle of zero");
			return -ENOENT;
		}
		err = qdisc_graft(dev, p, skb, n, clid, NULL, q, extack);
		if (err != 0)
			return err;
	} else {
		qdisc_notify(net, skb, n, clid, NULL, q);
	}
	return 0;
}

/*
 * Create/change qdisc.
 */

static int tc_modify_qdisc(struct sk_buff *skb, struct nlmsghdr *n,
			   struct netlink_ext_ack *extack)
{
	struct net *net = sock_net(skb->sk);
	struct tcmsg *tcm;
	struct nlattr *tca[TCA_MAX + 1];
	struct net_device *dev;
	u32 clid;
	struct Qdisc *q, *p;
	int err;

	if (!netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
		return -EPERM;

replay:
	/* Reinit, just in case something touches this. */
	err = nlmsg_parse_deprecated(n, sizeof(*tcm), tca, TCA_MAX,
				     rtm_tca_policy, extack);
	if (err < 0)
		return err;

	tcm = nlmsg_data(n);
	clid = tcm->tcm_parent;
	q = p = NULL;

	dev = __dev_get_by_index(net, tcm->tcm_ifindex);
	if (!dev)
		return -ENODEV;


	if (clid) {
		if (clid != TC_H_ROOT) {
			if (clid != TC_H_INGRESS) {
				p = qdisc_lookup(dev, TC_H_MAJ(clid));
				if (!p) {
					NL_SET_ERR_MSG(extack, "Failed to find specified qdisc");
					return -ENOENT;
				}
				q = qdisc_leaf(p, clid);
			} else if (dev_ingress_queue_create(dev)) {
				q = dev_ingress_queue(dev)->qdisc_sleeping;
			}
		} else {
			q = dev->qdisc;
		}

		/* It may be default qdisc, ignore it */
		if (q && q->handle == 0)
			q = NULL;

		if (!q || !tcm->tcm_handle || q->handle != tcm->tcm_handle) {
			if (tcm->tcm_handle) {
				if (q && !(n->nlmsg_flags & NLM_F_REPLACE)) {
					NL_SET_ERR_MSG(extack, "NLM_F_REPLACE needed to override");
					return -EEXIST;
				}
				if (TC_H_MIN(tcm->tcm_handle)) {
					NL_SET_ERR_MSG(extack, "Invalid minor handle");
					return -EINVAL;
				}
				q = qdisc_lookup(dev, tcm->tcm_handle);
				if (!q)
					goto create_n_graft;
				if (n->nlmsg_flags & NLM_F_EXCL) {
					NL_SET_ERR_MSG(extack, "Exclusivity flag on, cannot override");
					return -EEXIST;
				}
				if (tca[TCA_KIND] &&
				    nla_strcmp(tca[TCA_KIND], q->ops->id)) {
					NL_SET_ERR_MSG(extack, "Invalid qdisc name");
					return -EINVAL;
				}
				if (q == p ||
				    (p && check_loop(q, p, 0))) {
					NL_SET_ERR_MSG(extack, "Qdisc parent/child loop detected");
					return -ELOOP;
				}
				qdisc_refcount_inc(q);
				goto graft;
			} else {
				if (!q)
					goto create_n_graft;

				/* This magic test requires explanation.
				 *
				 *   We know, that some child q is already
				 *   attached to this parent and have choice:
				 *   either to change it or to create/graft new one.
				 *
				 *   1. We are allowed to create/graft only
				 *   if CREATE and REPLACE flags are set.
				 *
				 *   2. If EXCL is set, requestor wanted to say,
				 *   that qdisc tcm_handle is not expected
				 *   to exist, so that we choose create/graft too.
				 *
				 *   3. The last case is when no flags are set.
				 *   Alas, it is sort of hole in API, we
				 *   cannot decide what to do unambiguously.
				 *   For now we select create/graft, if
				 *   user gave KIND, which does not match existing.
				 */
				if ((n->nlmsg_flags & NLM_F_CREATE) &&
				    (n->nlmsg_flags & NLM_F_REPLACE) &&
				    ((n->nlmsg_flags & NLM_F_EXCL) ||
				     (tca[TCA_KIND] &&
				      nla_strcmp(tca[TCA_KIND], q->ops->id))))
					goto create_n_graft;
			}
		}
	} else {
		if (!tcm->tcm_handle) {
			NL_SET_ERR_MSG(extack, "Handle cannot be zero");
			return -EINVAL;
		}
		q = qdisc_lookup(dev, tcm->tcm_handle);
	}

	/* Change qdisc parameters */
	if (!q) {
		NL_SET_ERR_MSG(extack, "Specified qdisc not found");
		return -ENOENT;
	}
	if (n->nlmsg_flags & NLM_F_EXCL) {
		NL_SET_ERR_MSG(extack, "Exclusivity flag on, cannot modify");
		return -EEXIST;
	}
	if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], q->ops->id)) {
		NL_SET_ERR_MSG(extack, "Invalid qdisc name");
		return -EINVAL;
	}
	err = qdisc_change(q, tca, extack);
	if (err == 0)
		qdisc_notify(net, skb, n, clid, NULL, q);
	return err;

create_n_graft:
	if (!(n->nlmsg_flags & NLM_F_CREATE)) {
		NL_SET_ERR_MSG(extack, "Qdisc not found. To create specify NLM_F_CREATE flag");
		return -ENOENT;
	}
	if (clid == TC_H_INGRESS) {
		if (dev_ingress_queue(dev)) {
			q = qdisc_create(dev, dev_ingress_queue(dev), p,
					 tcm->tcm_parent, tcm->tcm_parent,
					 tca, &err, extack);
		} else {
			NL_SET_ERR_MSG(extack, "Cannot find ingress queue for specified device");
			err = -ENOENT;
		}
	} else {
		struct netdev_queue *dev_queue;

		if (p && p->ops->cl_ops && p->ops->cl_ops->select_queue)
			dev_queue = p->ops->cl_ops->select_queue(p, tcm);
		else if (p)
			dev_queue = p->dev_queue;
		else
			dev_queue = netdev_get_tx_queue(dev, 0);

		q = qdisc_create(dev, dev_queue, p,
				 tcm->tcm_parent, tcm->tcm_handle,
				 tca, &err, extack);
	}
	if (q == NULL) {
		if (err == -EAGAIN)
			goto replay;
		return err;
	}

graft:
	err = qdisc_graft(dev, p, skb, n, clid, q, NULL, extack);
	if (err) {
		if (q)
			qdisc_put(q);
		return err;
	}

	return 0;
}

static int tc_dump_qdisc_root(struct Qdisc *root, struct sk_buff *skb,
			      struct netlink_callback *cb,
			      int *q_idx_p, int s_q_idx, bool recur,
			      bool dump_invisible)
{
	int ret = 0, q_idx = *q_idx_p;
	struct Qdisc *q;
	int b;

	if (!root)
		return 0;

	q = root;
	if (q_idx < s_q_idx) {
		q_idx++;
	} else {
		if (!tc_qdisc_dump_ignore(q, dump_invisible) &&
		    tc_fill_qdisc(skb, q, q->parent, NETLINK_CB(cb->skb).portid,
				  cb->nlh->nlmsg_seq, NLM_F_MULTI,
				  RTM_NEWQDISC) <= 0)
			goto done;
		q_idx++;
	}

	/* If dumping singletons, there is no qdisc_dev(root) and the singleton
	 * itself has already been dumped.
	 *
	 * If we've already dumped the top-level (ingress) qdisc above and the global
	 * qdisc hashtable, we don't want to hit it again
	 */
	if (!qdisc_dev(root) || !recur)
		goto out;

	hash_for_each(qdisc_dev(root)->qdisc_hash, b, q, hash) {
		if (q_idx < s_q_idx) {
			q_idx++;
			continue;
		}
		if (!tc_qdisc_dump_ignore(q, dump_invisible) &&
		    tc_fill_qdisc(skb, q, q->parent, NETLINK_CB(cb->skb).portid,
				  cb->nlh->nlmsg_seq, NLM_F_MULTI,
				  RTM_NEWQDISC) <= 0)
			goto done;
		q_idx++;
	}

out:
	*q_idx_p = q_idx;
	return ret;
done:
	ret = -1;
	goto out;
}

static int tc_dump_qdisc(struct sk_buff *skb, struct netlink_callback *cb)
{
	struct net *net = sock_net(skb->sk);
	int idx, q_idx;
	int s_idx, s_q_idx;
	struct net_device *dev;
	const struct nlmsghdr *nlh = cb->nlh;
	struct nlattr *tca[TCA_MAX + 1];
	int err;

	s_idx = cb->args[0];
	s_q_idx = q_idx = cb->args[1];

	idx = 0;
	ASSERT_RTNL();

	err = nlmsg_parse_deprecated(nlh, sizeof(struct tcmsg), tca, TCA_MAX,
				     rtm_tca_policy, cb->extack);
	if (err < 0)
		return err;

	for_each_netdev(net, dev) {
		struct netdev_queue *dev_queue;

		if (idx < s_idx)
			goto cont;
		if (idx > s_idx)
			s_q_idx = 0;
		q_idx = 0;

		if (tc_dump_qdisc_root(dev->qdisc, skb, cb, &q_idx, s_q_idx,
				       true, tca[TCA_DUMP_INVISIBLE]) < 0)
			goto done;

		dev_queue = dev_ingress_queue(dev);
		if (dev_queue &&
		    tc_dump_qdisc_root(dev_queue->qdisc_sleeping, skb, cb,
				       &q_idx, s_q_idx, false,
				       tca[TCA_DUMP_INVISIBLE]) < 0)
			goto done;

cont:
		idx++;
	}

done:
	cb->args[0] = idx;
	cb->args[1] = q_idx;

	return skb->len;
}



/************************************************
 *	Traffic classes manipulation.		*
 ************************************************/

static int tc_fill_tclass(struct sk_buff *skb, struct Qdisc *q,
			  unsigned long cl,
			  u32 portid, u32 seq, u16 flags, int event)
{
	struct tcmsg *tcm;
	struct nlmsghdr  *nlh;
	unsigned char *b = skb_tail_pointer(skb);
	struct gnet_dump d;
	const struct Qdisc_class_ops *cl_ops = q->ops->cl_ops;

	cond_resched();
	nlh = nlmsg_put(skb, portid, seq, event, sizeof(*tcm), flags);
	if (!nlh)
		goto out_nlmsg_trim;
	tcm = nlmsg_data(nlh);
	tcm->tcm_family = AF_UNSPEC;
	tcm->tcm__pad1 = 0;
	tcm->tcm__pad2 = 0;
	tcm->tcm_ifindex = qdisc_dev(q)->ifindex;
	tcm->tcm_parent = q->handle;
	tcm->tcm_handle = q->handle;
	tcm->tcm_info = 0;
	if (nla_put_string(skb, TCA_KIND, q->ops->id))
		goto nla_put_failure;
	if (cl_ops->dump && cl_ops->dump(q, cl, skb, tcm) < 0)
		goto nla_put_failure;

	if (gnet_stats_start_copy_compat(skb, TCA_STATS2, TCA_STATS, TCA_XSTATS,
					 NULL, &d, TCA_PAD) < 0)
		goto nla_put_failure;

	if (cl_ops->dump_stats && cl_ops->dump_stats(q, cl, &d) < 0)
		goto nla_put_failure;

	if (gnet_stats_finish_copy(&d) < 0)
		goto nla_put_failure;

	nlh->nlmsg_len = skb_tail_pointer(skb) - b;
	return skb->len;

out_nlmsg_trim:
nla_put_failure:
	nlmsg_trim(skb, b);
	return -1;
}

static int tclass_notify(struct net *net, struct sk_buff *oskb,
			 struct nlmsghdr *n, struct Qdisc *q,
			 unsigned long cl, int event)
{
	struct sk_buff *skb;
	u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
	int err = 0;

	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
	if (!skb)
		return -ENOBUFS;

	if (tc_fill_tclass(skb, q, cl, portid, n->nlmsg_seq, 0, event) < 0) {
		kfree_skb(skb);
		return -EINVAL;
	}

	err = rtnetlink_send(skb, net, portid, RTNLGRP_TC,
			     n->nlmsg_flags & NLM_F_ECHO);
	if (err > 0)
		err = 0;
	return err;
}

static int tclass_del_notify(struct net *net,
			     const struct Qdisc_class_ops *cops,
			     struct sk_buff *oskb, struct nlmsghdr *n,
			     struct Qdisc *q, unsigned long cl)
{
	u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
	struct sk_buff *skb;
	int err = 0;

	if (!cops->delete)
		return -EOPNOTSUPP;

	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
	if (!skb)
		return -ENOBUFS;

	if (tc_fill_tclass(skb, q, cl, portid, n->nlmsg_seq, 0,
			   RTM_DELTCLASS) < 0) {
		kfree_skb(skb);
		return -EINVAL;
	}

	err = cops->delete(q, cl);
	if (err) {
		kfree_skb(skb);
		return err;
	}

	err = rtnetlink_send(skb, net, portid, RTNLGRP_TC,
			     n->nlmsg_flags & NLM_F_ECHO);
	if (err > 0)
		err = 0;
	return err;
}

#ifdef CONFIG_NET_CLS

struct tcf_bind_args {
	struct tcf_walker w;
	unsigned long base;
	unsigned long cl;
	u32 classid;
};

static int tcf_node_bind(struct tcf_proto *tp, void *n, struct tcf_walker *arg)
{
	struct tcf_bind_args *a = (void *)arg;

	if (tp->ops->bind_class) {
		struct Qdisc *q = tcf_block_q(tp->chain->block);

		sch_tree_lock(q);
		tp->ops->bind_class(n, a->classid, a->cl, q, a->base);
		sch_tree_unlock(q);
	}
	return 0;
}

struct tc_bind_class_args {
	struct qdisc_walker w;
	unsigned long new_cl;
	u32 portid;
	u32 clid;
};

static int tc_bind_class_walker(struct Qdisc *q, unsigned long cl,
				struct qdisc_walker *w)
{
	struct tc_bind_class_args *a = (struct tc_bind_class_args *)w;
	const struct Qdisc_class_ops *cops = q->ops->cl_ops;
	struct tcf_block *block;
	struct tcf_chain *chain;

	block = cops->tcf_block(q, cl, NULL);
	if (!block)
		return 0;
	for (chain = tcf_get_next_chain(block, NULL);
	     chain;
	     chain = tcf_get_next_chain(block, chain)) {
		struct tcf_proto *tp;

		for (tp = tcf_get_next_proto(chain, NULL, true);
		     tp; tp = tcf_get_next_proto(chain, tp, true)) {
			struct tcf_bind_args arg = {};

			arg.w.fn = tcf_node_bind;
			arg.classid = a->clid;
			arg.base = cl;
			arg.cl = a->new_cl;
			tp->ops->walk(tp, &arg.w, true);
		}
	}

	return 0;
}

static void tc_bind_tclass(struct Qdisc *q, u32 portid, u32 clid,
			   unsigned long new_cl)
{
	const struct Qdisc_class_ops *cops = q->ops->cl_ops;
	struct tc_bind_class_args args = {};

	if (!cops->tcf_block)
		return;
	args.portid = portid;
	args.clid = clid;
	args.new_cl = new_cl;
	args.w.fn = tc_bind_class_walker;
	q->ops->cl_ops->walk(q, &args.w);
}

#else

static void tc_bind_tclass(struct Qdisc *q, u32 portid, u32 clid,
			   unsigned long new_cl)
{
}

#endif

static int tc_ctl_tclass(struct sk_buff *skb, struct nlmsghdr *n,
			 struct netlink_ext_ack *extack)
{
	struct net *net = sock_net(skb->sk);
	struct tcmsg *tcm = nlmsg_data(n);
	struct nlattr *tca[TCA_MAX + 1];
	struct net_device *dev;
	struct Qdisc *q = NULL;
	const struct Qdisc_class_ops *cops;
	unsigned long cl = 0;
	unsigned long new_cl;
	u32 portid;
	u32 clid;
	u32 qid;
	int err;

	if ((n->nlmsg_type != RTM_GETTCLASS) &&
	    !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
		return -EPERM;

	err = nlmsg_parse_deprecated(n, sizeof(*tcm), tca, TCA_MAX,
				     rtm_tca_policy, extack);
	if (err < 0)
		return err;

	dev = __dev_get_by_index(net, tcm->tcm_ifindex);
	if (!dev)
		return -ENODEV;

	/*
	   parent == TC_H_UNSPEC - unspecified parent.
	   parent == TC_H_ROOT   - class is root, which has no parent.
	   parent == X:0	 - parent is root class.
	   parent == X:Y	 - parent is a node in hierarchy.
	   parent == 0:Y	 - parent is X:Y, where X:0 is qdisc.

	   handle == 0:0	 - generate handle from kernel pool.
	   handle == 0:Y	 - class is X:Y, where X:0 is qdisc.
	   handle == X:Y	 - clear.
	   handle == X:0	 - root class.
	 */

	/* Step 1. Determine qdisc handle X:0 */

	portid = tcm->tcm_parent;
	clid = tcm->tcm_handle;
	qid = TC_H_MAJ(clid);

	if (portid != TC_H_ROOT) {
		u32 qid1 = TC_H_MAJ(portid);

		if (qid && qid1) {
			/* If both majors are known, they must be identical. */
			if (qid != qid1)
				return -EINVAL;
		} else if (qid1) {
			qid = qid1;
		} else if (qid == 0)
			qid = dev->qdisc->handle;

		/* Now qid is genuine qdisc handle consistent
		 * both with parent and child.
		 *
		 * TC_H_MAJ(portid) still may be unspecified, complete it now.
		 */
		if (portid)
			portid = TC_H_MAKE(qid, portid);
	} else {
		if (qid == 0)
			qid = dev->qdisc->handle;
	}

	/* OK. Locate qdisc */
	q = qdisc_lookup(dev, qid);
	if (!q)
		return -ENOENT;

	/* An check that it supports classes */
	cops = q->ops->cl_ops;
	if (cops == NULL)
		return -EINVAL;

	/* Now try to get class */
	if (clid == 0) {
		if (portid == TC_H_ROOT)
			clid = qid;
	} else
		clid = TC_H_MAKE(qid, clid);

	if (clid)
		cl = cops->find(q, clid);

	if (cl == 0) {
		err = -ENOENT;
		if (n->nlmsg_type != RTM_NEWTCLASS ||
		    !(n->nlmsg_flags & NLM_F_CREATE))
			goto out;
	} else {
		switch (n->nlmsg_type) {
		case RTM_NEWTCLASS:
			err = -EEXIST;
			if (n->nlmsg_flags & NLM_F_EXCL)
				goto out;
			break;
		case RTM_DELTCLASS:
			err = tclass_del_notify(net, cops, skb, n, q, cl);
			/* Unbind the class with flilters with 0 */
			tc_bind_tclass(q, portid, clid, 0);
			goto out;
		case RTM_GETTCLASS:
			err = tclass_notify(net, skb, n, q, cl, RTM_NEWTCLASS);
			goto out;
		default:
			err = -EINVAL;
			goto out;
		}
	}

	if (tca[TCA_INGRESS_BLOCK] || tca[TCA_EGRESS_BLOCK]) {
		NL_SET_ERR_MSG(extack, "Shared blocks are not supported for classes");
		return -EOPNOTSUPP;
	}

	new_cl = cl;
	err = -EOPNOTSUPP;
	if (cops->change)
		err = cops->change(q, clid, portid, tca, &new_cl, extack);
	if (err == 0) {
		tclass_notify(net, skb, n, q, new_cl, RTM_NEWTCLASS);
		/* We just create a new class, need to do reverse binding. */
		if (cl != new_cl)
			tc_bind_tclass(q, portid, clid, new_cl);
	}
out:
	return err;
}

struct qdisc_dump_args {
	struct qdisc_walker	w;
	struct sk_buff		*skb;
	struct netlink_callback	*cb;
};

static int qdisc_class_dump(struct Qdisc *q, unsigned long cl,
			    struct qdisc_walker *arg)
{
	struct qdisc_dump_args *a = (struct qdisc_dump_args *)arg;

	return tc_fill_tclass(a->skb, q, cl, NETLINK_CB(a->cb->skb).portid,
			      a->cb->nlh->nlmsg_seq, NLM_F_MULTI,
			      RTM_NEWTCLASS);
}

static int tc_dump_tclass_qdisc(struct Qdisc *q, struct sk_buff *skb,
				struct tcmsg *tcm, struct netlink_callback *cb,
				int *t_p, int s_t)
{
	struct qdisc_dump_args arg;

	if (tc_qdisc_dump_ignore(q, false) ||
	    *t_p < s_t || !q->ops->cl_ops ||
	    (tcm->tcm_parent &&
	     TC_H_MAJ(tcm->tcm_parent) != q->handle)) {
		(*t_p)++;
		return 0;
	}
	if (*t_p > s_t)
		memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0]));
	arg.w.fn = qdisc_class_dump;
	arg.skb = skb;
	arg.cb = cb;
	arg.w.stop  = 0;
	arg.w.skip = cb->args[1];
	arg.w.count = 0;
	q->ops->cl_ops->walk(q, &arg.w);
	cb->args[1] = arg.w.count;
	if (arg.w.stop)
		return -1;
	(*t_p)++;
	return 0;
}

static int tc_dump_tclass_root(struct Qdisc *root, struct sk_buff *skb,
			       struct tcmsg *tcm, struct netlink_callback *cb,
			       int *t_p, int s_t)
{
	struct Qdisc *q;
	int b;

	if (!root)
		return 0;

	if (tc_dump_tclass_qdisc(root, skb, tcm, cb, t_p, s_t) < 0)
		return -1;

	if (!qdisc_dev(root))
		return 0;

	if (tcm->tcm_parent) {
		q = qdisc_match_from_root(root, TC_H_MAJ(tcm->tcm_parent));
		if (q && q != root &&
		    tc_dump_tclass_qdisc(q, skb, tcm, cb, t_p, s_t) < 0)
			return -1;
		return 0;
	}
	hash_for_each(qdisc_dev(root)->qdisc_hash, b, q, hash) {
		if (tc_dump_tclass_qdisc(q, skb, tcm, cb, t_p, s_t) < 0)
			return -1;
	}

	return 0;
}

static int tc_dump_tclass(struct sk_buff *skb, struct netlink_callback *cb)
{
	struct tcmsg *tcm = nlmsg_data(cb->nlh);
	struct net *net = sock_net(skb->sk);
	struct netdev_queue *dev_queue;
	struct net_device *dev;
	int t, s_t;

	if (nlmsg_len(cb->nlh) < sizeof(*tcm))
		return 0;
	dev = dev_get_by_index(net, tcm->tcm_ifindex);
	if (!dev)
		return 0;

	s_t = cb->args[0];
	t = 0;

	if (tc_dump_tclass_root(dev->qdisc, skb, tcm, cb, &t, s_t) < 0)
		goto done;

	dev_queue = dev_ingress_queue(dev);
	if (dev_queue &&
	    tc_dump_tclass_root(dev_queue->qdisc_sleeping, skb, tcm, cb,
				&t, s_t) < 0)
		goto done;

done:
	cb->args[0] = t;

	dev_put(dev);
	return skb->len;
}

#ifdef CONFIG_PROC_FS
static int psched_show(struct seq_file *seq, void *v)
{
	seq_printf(seq, "%08x %08x %08x %08x\n",
		   (u32)NSEC_PER_USEC, (u32)PSCHED_TICKS2NS(1),
		   1000000,
		   (u32)NSEC_PER_SEC / hrtimer_resolution);

	return 0;
}

static int __net_init psched_net_init(struct net *net)
{
	struct proc_dir_entry *e;

	e = proc_create_single("psched", 0, net->proc_net, psched_show);
	if (e == NULL)
		return -ENOMEM;

	return 0;
}

static void __net_exit psched_net_exit(struct net *net)
{
	remove_proc_entry("psched", net->proc_net);
}
#else
static int __net_init psched_net_init(struct net *net)
{
	return 0;
}

static void __net_exit psched_net_exit(struct net *net)
{
}
#endif

static struct pernet_operations psched_net_ops = {
	.init = psched_net_init,
	.exit = psched_net_exit,
};

static int __init pktsched_init(void)
{
	int err;

	err = register_pernet_subsys(&psched_net_ops);
	if (err) {
		pr_err("pktsched_init: "
		       "cannot initialize per netns operations\n");
		return err;
	}

	register_qdisc(&pfifo_fast_ops);
	register_qdisc(&pfifo_qdisc_ops);
	register_qdisc(&bfifo_qdisc_ops);
	register_qdisc(&pfifo_head_drop_qdisc_ops);
	register_qdisc(&mq_qdisc_ops);
	register_qdisc(&noqueue_qdisc_ops);

	rtnl_register(PF_UNSPEC, RTM_NEWQDISC, tc_modify_qdisc, NULL, 0);
	rtnl_register(PF_UNSPEC, RTM_DELQDISC, tc_get_qdisc, NULL, 0);
	rtnl_register(PF_UNSPEC, RTM_GETQDISC, tc_get_qdisc, tc_dump_qdisc,
		      0);
	rtnl_register(PF_UNSPEC, RTM_NEWTCLASS, tc_ctl_tclass, NULL, 0);
	rtnl_register(PF_UNSPEC, RTM_DELTCLASS, tc_ctl_tclass, NULL, 0);
	rtnl_register(PF_UNSPEC, RTM_GETTCLASS, tc_ctl_tclass, tc_dump_tclass,
		      0);

	return 0;
}

subsys_initcall(pktsched_init);