summaryrefslogtreecommitdiff
path: root/drivers/net/veth.c
blob: d43e62ebc2fcd5d30f4717454ab5c9d089502d15 (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
// SPDX-License-Identifier: GPL-2.0-only
/*
 *  drivers/net/veth.c
 *
 *  Copyright (C) 2007 OpenVZ http://openvz.org, SWsoft Inc
 *
 * Author: Pavel Emelianov <xemul@openvz.org>
 * Ethtool interface from: Eric W. Biederman <ebiederm@xmission.com>
 *
 */

#include <linux/netdevice.h>
#include <linux/slab.h>
#include <linux/ethtool.h>
#include <linux/etherdevice.h>
#include <linux/u64_stats_sync.h>

#include <net/rtnetlink.h>
#include <net/dst.h>
#include <net/xfrm.h>
#include <net/xdp.h>
#include <linux/veth.h>
#include <linux/module.h>
#include <linux/bpf.h>
#include <linux/filter.h>
#include <linux/ptr_ring.h>
#include <linux/bpf_trace.h>
#include <linux/net_tstamp.h>
#include <net/page_pool/helpers.h>

#define DRV_NAME	"veth"
#define DRV_VERSION	"1.0"

#define VETH_XDP_FLAG		BIT(0)
#define VETH_RING_SIZE		256
#define VETH_XDP_HEADROOM	(XDP_PACKET_HEADROOM + NET_IP_ALIGN)

#define VETH_XDP_TX_BULK_SIZE	16
#define VETH_XDP_BATCH		16

struct veth_stats {
	u64	rx_drops;
	/* xdp */
	u64	xdp_packets;
	u64	xdp_bytes;
	u64	xdp_redirect;
	u64	xdp_drops;
	u64	xdp_tx;
	u64	xdp_tx_err;
	u64	peer_tq_xdp_xmit;
	u64	peer_tq_xdp_xmit_err;
};

struct veth_rq_stats {
	struct veth_stats	vs;
	struct u64_stats_sync	syncp;
};

struct veth_rq {
	struct napi_struct	xdp_napi;
	struct napi_struct __rcu *napi; /* points to xdp_napi when the latter is initialized */
	struct net_device	*dev;
	struct bpf_prog __rcu	*xdp_prog;
	struct xdp_mem_info	xdp_mem;
	struct veth_rq_stats	stats;
	bool			rx_notify_masked;
	struct ptr_ring		xdp_ring;
	struct xdp_rxq_info	xdp_rxq;
	struct page_pool	*page_pool;
};

struct veth_priv {
	struct net_device __rcu	*peer;
	atomic64_t		dropped;
	struct bpf_prog		*_xdp_prog;
	struct veth_rq		*rq;
	unsigned int		requested_headroom;
};

struct veth_xdp_tx_bq {
	struct xdp_frame *q[VETH_XDP_TX_BULK_SIZE];
	unsigned int count;
};

/*
 * ethtool interface
 */

struct veth_q_stat_desc {
	char	desc[ETH_GSTRING_LEN];
	size_t	offset;
};

#define VETH_RQ_STAT(m)	offsetof(struct veth_stats, m)

static const struct veth_q_stat_desc veth_rq_stats_desc[] = {
	{ "xdp_packets",	VETH_RQ_STAT(xdp_packets) },
	{ "xdp_bytes",		VETH_RQ_STAT(xdp_bytes) },
	{ "drops",		VETH_RQ_STAT(rx_drops) },
	{ "xdp_redirect",	VETH_RQ_STAT(xdp_redirect) },
	{ "xdp_drops",		VETH_RQ_STAT(xdp_drops) },
	{ "xdp_tx",		VETH_RQ_STAT(xdp_tx) },
	{ "xdp_tx_errors",	VETH_RQ_STAT(xdp_tx_err) },
};

#define VETH_RQ_STATS_LEN	ARRAY_SIZE(veth_rq_stats_desc)

static const struct veth_q_stat_desc veth_tq_stats_desc[] = {
	{ "xdp_xmit",		VETH_RQ_STAT(peer_tq_xdp_xmit) },
	{ "xdp_xmit_errors",	VETH_RQ_STAT(peer_tq_xdp_xmit_err) },
};

#define VETH_TQ_STATS_LEN	ARRAY_SIZE(veth_tq_stats_desc)

static struct {
	const char string[ETH_GSTRING_LEN];
} ethtool_stats_keys[] = {
	{ "peer_ifindex" },
};

struct veth_xdp_buff {
	struct xdp_buff xdp;
	struct sk_buff *skb;
};

static int veth_get_link_ksettings(struct net_device *dev,
				   struct ethtool_link_ksettings *cmd)
{
	cmd->base.speed		= SPEED_10000;
	cmd->base.duplex	= DUPLEX_FULL;
	cmd->base.port		= PORT_TP;
	cmd->base.autoneg	= AUTONEG_DISABLE;
	return 0;
}

static void veth_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
{
	strscpy(info->driver, DRV_NAME, sizeof(info->driver));
	strscpy(info->version, DRV_VERSION, sizeof(info->version));
}

static void veth_get_strings(struct net_device *dev, u32 stringset, u8 *buf)
{
	u8 *p = buf;
	int i, j;

	switch(stringset) {
	case ETH_SS_STATS:
		memcpy(p, &ethtool_stats_keys, sizeof(ethtool_stats_keys));
		p += sizeof(ethtool_stats_keys);
		for (i = 0; i < dev->real_num_rx_queues; i++)
			for (j = 0; j < VETH_RQ_STATS_LEN; j++)
				ethtool_sprintf(&p, "rx_queue_%u_%.18s",
						i, veth_rq_stats_desc[j].desc);

		for (i = 0; i < dev->real_num_tx_queues; i++)
			for (j = 0; j < VETH_TQ_STATS_LEN; j++)
				ethtool_sprintf(&p, "tx_queue_%u_%.18s",
						i, veth_tq_stats_desc[j].desc);

		page_pool_ethtool_stats_get_strings(p);
		break;
	}
}

static int veth_get_sset_count(struct net_device *dev, int sset)
{
	switch (sset) {
	case ETH_SS_STATS:
		return ARRAY_SIZE(ethtool_stats_keys) +
		       VETH_RQ_STATS_LEN * dev->real_num_rx_queues +
		       VETH_TQ_STATS_LEN * dev->real_num_tx_queues +
		       page_pool_ethtool_stats_get_count();
	default:
		return -EOPNOTSUPP;
	}
}

static void veth_get_page_pool_stats(struct net_device *dev, u64 *data)
{
#ifdef CONFIG_PAGE_POOL_STATS
	struct veth_priv *priv = netdev_priv(dev);
	struct page_pool_stats pp_stats = {};
	int i;

	for (i = 0; i < dev->real_num_rx_queues; i++) {
		if (!priv->rq[i].page_pool)
			continue;
		page_pool_get_stats(priv->rq[i].page_pool, &pp_stats);
	}
	page_pool_ethtool_stats_get(data, &pp_stats);
#endif /* CONFIG_PAGE_POOL_STATS */
}

static void veth_get_ethtool_stats(struct net_device *dev,
		struct ethtool_stats *stats, u64 *data)
{
	struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
	struct net_device *peer = rtnl_dereference(priv->peer);
	int i, j, idx, pp_idx;

	data[0] = peer ? peer->ifindex : 0;
	idx = 1;
	for (i = 0; i < dev->real_num_rx_queues; i++) {
		const struct veth_rq_stats *rq_stats = &priv->rq[i].stats;
		const void *stats_base = (void *)&rq_stats->vs;
		unsigned int start;
		size_t offset;

		do {
			start = u64_stats_fetch_begin(&rq_stats->syncp);
			for (j = 0; j < VETH_RQ_STATS_LEN; j++) {
				offset = veth_rq_stats_desc[j].offset;
				data[idx + j] = *(u64 *)(stats_base + offset);
			}
		} while (u64_stats_fetch_retry(&rq_stats->syncp, start));
		idx += VETH_RQ_STATS_LEN;
	}
	pp_idx = idx;

	if (!peer)
		goto page_pool_stats;

	rcv_priv = netdev_priv(peer);
	for (i = 0; i < peer->real_num_rx_queues; i++) {
		const struct veth_rq_stats *rq_stats = &rcv_priv->rq[i].stats;
		const void *base = (void *)&rq_stats->vs;
		unsigned int start, tx_idx = idx;
		size_t offset;

		tx_idx += (i % dev->real_num_tx_queues) * VETH_TQ_STATS_LEN;
		do {
			start = u64_stats_fetch_begin(&rq_stats->syncp);
			for (j = 0; j < VETH_TQ_STATS_LEN; j++) {
				offset = veth_tq_stats_desc[j].offset;
				data[tx_idx + j] += *(u64 *)(base + offset);
			}
		} while (u64_stats_fetch_retry(&rq_stats->syncp, start));
		pp_idx = tx_idx + VETH_TQ_STATS_LEN;
	}

page_pool_stats:
	veth_get_page_pool_stats(dev, &data[pp_idx]);
}

static void veth_get_channels(struct net_device *dev,
			      struct ethtool_channels *channels)
{
	channels->tx_count = dev->real_num_tx_queues;
	channels->rx_count = dev->real_num_rx_queues;
	channels->max_tx = dev->num_tx_queues;
	channels->max_rx = dev->num_rx_queues;
}

static int veth_set_channels(struct net_device *dev,
			     struct ethtool_channels *ch);

static const struct ethtool_ops veth_ethtool_ops = {
	.get_drvinfo		= veth_get_drvinfo,
	.get_link		= ethtool_op_get_link,
	.get_strings		= veth_get_strings,
	.get_sset_count		= veth_get_sset_count,
	.get_ethtool_stats	= veth_get_ethtool_stats,
	.get_link_ksettings	= veth_get_link_ksettings,
	.get_ts_info		= ethtool_op_get_ts_info,
	.get_channels		= veth_get_channels,
	.set_channels		= veth_set_channels,
};

/* general routines */

static bool veth_is_xdp_frame(void *ptr)
{
	return (unsigned long)ptr & VETH_XDP_FLAG;
}

static struct xdp_frame *veth_ptr_to_xdp(void *ptr)
{
	return (void *)((unsigned long)ptr & ~VETH_XDP_FLAG);
}

static void *veth_xdp_to_ptr(struct xdp_frame *xdp)
{
	return (void *)((unsigned long)xdp | VETH_XDP_FLAG);
}

static void veth_ptr_free(void *ptr)
{
	if (veth_is_xdp_frame(ptr))
		xdp_return_frame(veth_ptr_to_xdp(ptr));
	else
		kfree_skb(ptr);
}

static void __veth_xdp_flush(struct veth_rq *rq)
{
	/* Write ptr_ring before reading rx_notify_masked */
	smp_mb();
	if (!READ_ONCE(rq->rx_notify_masked) &&
	    napi_schedule_prep(&rq->xdp_napi)) {
		WRITE_ONCE(rq->rx_notify_masked, true);
		__napi_schedule(&rq->xdp_napi);
	}
}

static int veth_xdp_rx(struct veth_rq *rq, struct sk_buff *skb)
{
	if (unlikely(ptr_ring_produce(&rq->xdp_ring, skb))) {
		dev_kfree_skb_any(skb);
		return NET_RX_DROP;
	}

	return NET_RX_SUCCESS;
}

static int veth_forward_skb(struct net_device *dev, struct sk_buff *skb,
			    struct veth_rq *rq, bool xdp)
{
	return __dev_forward_skb(dev, skb) ?: xdp ?
		veth_xdp_rx(rq, skb) :
		__netif_rx(skb);
}

/* return true if the specified skb has chances of GRO aggregation
 * Don't strive for accuracy, but try to avoid GRO overhead in the most
 * common scenarios.
 * When XDP is enabled, all traffic is considered eligible, as the xmit
 * device has TSO off.
 * When TSO is enabled on the xmit device, we are likely interested only
 * in UDP aggregation, explicitly check for that if the skb is suspected
 * - the sock_wfree destructor is used by UDP, ICMP and XDP sockets -
 * to belong to locally generated UDP traffic.
 */
static bool veth_skb_is_eligible_for_gro(const struct net_device *dev,
					 const struct net_device *rcv,
					 const struct sk_buff *skb)
{
	return !(dev->features & NETIF_F_ALL_TSO) ||
		(skb->destructor == sock_wfree &&
		 rcv->features & (NETIF_F_GRO_FRAGLIST | NETIF_F_GRO_UDP_FWD));
}

static netdev_tx_t veth_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
	struct veth_rq *rq = NULL;
	struct net_device *rcv;
	int length = skb->len;
	bool use_napi = false;
	int rxq;

	rcu_read_lock();
	rcv = rcu_dereference(priv->peer);
	if (unlikely(!rcv) || !pskb_may_pull(skb, ETH_HLEN)) {
		kfree_skb(skb);
		goto drop;
	}

	rcv_priv = netdev_priv(rcv);
	rxq = skb_get_queue_mapping(skb);
	if (rxq < rcv->real_num_rx_queues) {
		rq = &rcv_priv->rq[rxq];

		/* The napi pointer is available when an XDP program is
		 * attached or when GRO is enabled
		 * Don't bother with napi/GRO if the skb can't be aggregated
		 */
		use_napi = rcu_access_pointer(rq->napi) &&
			   veth_skb_is_eligible_for_gro(dev, rcv, skb);
	}

	skb_tx_timestamp(skb);
	if (likely(veth_forward_skb(rcv, skb, rq, use_napi) == NET_RX_SUCCESS)) {
		if (!use_napi)
			dev_lstats_add(dev, length);
		else
			__veth_xdp_flush(rq);
	} else {
drop:
		atomic64_inc(&priv->dropped);
	}

	rcu_read_unlock();

	return NETDEV_TX_OK;
}

static u64 veth_stats_tx(struct net_device *dev, u64 *packets, u64 *bytes)
{
	struct veth_priv *priv = netdev_priv(dev);

	dev_lstats_read(dev, packets, bytes);
	return atomic64_read(&priv->dropped);
}

static void veth_stats_rx(struct veth_stats *result, struct net_device *dev)
{
	struct veth_priv *priv = netdev_priv(dev);
	int i;

	result->peer_tq_xdp_xmit_err = 0;
	result->xdp_packets = 0;
	result->xdp_tx_err = 0;
	result->xdp_bytes = 0;
	result->rx_drops = 0;
	for (i = 0; i < dev->num_rx_queues; i++) {
		u64 packets, bytes, drops, xdp_tx_err, peer_tq_xdp_xmit_err;
		struct veth_rq_stats *stats = &priv->rq[i].stats;
		unsigned int start;

		do {
			start = u64_stats_fetch_begin(&stats->syncp);
			peer_tq_xdp_xmit_err = stats->vs.peer_tq_xdp_xmit_err;
			xdp_tx_err = stats->vs.xdp_tx_err;
			packets = stats->vs.xdp_packets;
			bytes = stats->vs.xdp_bytes;
			drops = stats->vs.rx_drops;
		} while (u64_stats_fetch_retry(&stats->syncp, start));
		result->peer_tq_xdp_xmit_err += peer_tq_xdp_xmit_err;
		result->xdp_tx_err += xdp_tx_err;
		result->xdp_packets += packets;
		result->xdp_bytes += bytes;
		result->rx_drops += drops;
	}
}

static void veth_get_stats64(struct net_device *dev,
			     struct rtnl_link_stats64 *tot)
{
	struct veth_priv *priv = netdev_priv(dev);
	struct net_device *peer;
	struct veth_stats rx;
	u64 packets, bytes;

	tot->tx_dropped = veth_stats_tx(dev, &packets, &bytes);
	tot->tx_bytes = bytes;
	tot->tx_packets = packets;

	veth_stats_rx(&rx, dev);
	tot->tx_dropped += rx.xdp_tx_err;
	tot->rx_dropped = rx.rx_drops + rx.peer_tq_xdp_xmit_err;
	tot->rx_bytes = rx.xdp_bytes;
	tot->rx_packets = rx.xdp_packets;

	rcu_read_lock();
	peer = rcu_dereference(priv->peer);
	if (peer) {
		veth_stats_tx(peer, &packets, &bytes);
		tot->rx_bytes += bytes;
		tot->rx_packets += packets;

		veth_stats_rx(&rx, peer);
		tot->tx_dropped += rx.peer_tq_xdp_xmit_err;
		tot->rx_dropped += rx.xdp_tx_err;
		tot->tx_bytes += rx.xdp_bytes;
		tot->tx_packets += rx.xdp_packets;
	}
	rcu_read_unlock();
}

/* fake multicast ability */
static void veth_set_multicast_list(struct net_device *dev)
{
}

static int veth_select_rxq(struct net_device *dev)
{
	return smp_processor_id() % dev->real_num_rx_queues;
}

static struct net_device *veth_peer_dev(struct net_device *dev)
{
	struct veth_priv *priv = netdev_priv(dev);

	/* Callers must be under RCU read side. */
	return rcu_dereference(priv->peer);
}

static int veth_xdp_xmit(struct net_device *dev, int n,
			 struct xdp_frame **frames,
			 u32 flags, bool ndo_xmit)
{
	struct veth_priv *rcv_priv, *priv = netdev_priv(dev);
	int i, ret = -ENXIO, nxmit = 0;
	struct net_device *rcv;
	unsigned int max_len;
	struct veth_rq *rq;

	if (unlikely(flags & ~XDP_XMIT_FLAGS_MASK))
		return -EINVAL;

	rcu_read_lock();
	rcv = rcu_dereference(priv->peer);
	if (unlikely(!rcv))
		goto out;

	rcv_priv = netdev_priv(rcv);
	rq = &rcv_priv->rq[veth_select_rxq(rcv)];
	/* The napi pointer is set if NAPI is enabled, which ensures that
	 * xdp_ring is initialized on receive side and the peer device is up.
	 */
	if (!rcu_access_pointer(rq->napi))
		goto out;

	max_len = rcv->mtu + rcv->hard_header_len + VLAN_HLEN;

	spin_lock(&rq->xdp_ring.producer_lock);
	for (i = 0; i < n; i++) {
		struct xdp_frame *frame = frames[i];
		void *ptr = veth_xdp_to_ptr(frame);

		if (unlikely(xdp_get_frame_len(frame) > max_len ||
			     __ptr_ring_produce(&rq->xdp_ring, ptr)))
			break;
		nxmit++;
	}
	spin_unlock(&rq->xdp_ring.producer_lock);

	if (flags & XDP_XMIT_FLUSH)
		__veth_xdp_flush(rq);

	ret = nxmit;
	if (ndo_xmit) {
		u64_stats_update_begin(&rq->stats.syncp);
		rq->stats.vs.peer_tq_xdp_xmit += nxmit;
		rq->stats.vs.peer_tq_xdp_xmit_err += n - nxmit;
		u64_stats_update_end(&rq->stats.syncp);
	}

out:
	rcu_read_unlock();

	return ret;
}

static int veth_ndo_xdp_xmit(struct net_device *dev, int n,
			     struct xdp_frame **frames, u32 flags)
{
	int err;

	err = veth_xdp_xmit(dev, n, frames, flags, true);
	if (err < 0) {
		struct veth_priv *priv = netdev_priv(dev);

		atomic64_add(n, &priv->dropped);
	}

	return err;
}

static void veth_xdp_flush_bq(struct veth_rq *rq, struct veth_xdp_tx_bq *bq)
{
	int sent, i, err = 0, drops;

	sent = veth_xdp_xmit(rq->dev, bq->count, bq->q, 0, false);
	if (sent < 0) {
		err = sent;
		sent = 0;
	}

	for (i = sent; unlikely(i < bq->count); i++)
		xdp_return_frame(bq->q[i]);

	drops = bq->count - sent;
	trace_xdp_bulk_tx(rq->dev, sent, drops, err);

	u64_stats_update_begin(&rq->stats.syncp);
	rq->stats.vs.xdp_tx += sent;
	rq->stats.vs.xdp_tx_err += drops;
	u64_stats_update_end(&rq->stats.syncp);

	bq->count = 0;
}

static void veth_xdp_flush(struct veth_rq *rq, struct veth_xdp_tx_bq *bq)
{
	struct veth_priv *rcv_priv, *priv = netdev_priv(rq->dev);
	struct net_device *rcv;
	struct veth_rq *rcv_rq;

	rcu_read_lock();
	veth_xdp_flush_bq(rq, bq);
	rcv = rcu_dereference(priv->peer);
	if (unlikely(!rcv))
		goto out;

	rcv_priv = netdev_priv(rcv);
	rcv_rq = &rcv_priv->rq[veth_select_rxq(rcv)];
	/* xdp_ring is initialized on receive side? */
	if (unlikely(!rcu_access_pointer(rcv_rq->xdp_prog)))
		goto out;

	__veth_xdp_flush(rcv_rq);
out:
	rcu_read_unlock();
}

static int veth_xdp_tx(struct veth_rq *rq, struct xdp_buff *xdp,
		       struct veth_xdp_tx_bq *bq)
{
	struct xdp_frame *frame = xdp_convert_buff_to_frame(xdp);

	if (unlikely(!frame))
		return -EOVERFLOW;

	if (unlikely(bq->count == VETH_XDP_TX_BULK_SIZE))
		veth_xdp_flush_bq(rq, bq);

	bq->q[bq->count++] = frame;

	return 0;
}

static struct xdp_frame *veth_xdp_rcv_one(struct veth_rq *rq,
					  struct xdp_frame *frame,
					  struct veth_xdp_tx_bq *bq,
					  struct veth_stats *stats)
{
	struct xdp_frame orig_frame;
	struct bpf_prog *xdp_prog;

	rcu_read_lock();
	xdp_prog = rcu_dereference(rq->xdp_prog);
	if (likely(xdp_prog)) {
		struct veth_xdp_buff vxbuf;
		struct xdp_buff *xdp = &vxbuf.xdp;
		u32 act;

		xdp_convert_frame_to_buff(frame, xdp);
		xdp->rxq = &rq->xdp_rxq;
		vxbuf.skb = NULL;

		act = bpf_prog_run_xdp(xdp_prog, xdp);

		switch (act) {
		case XDP_PASS:
			if (xdp_update_frame_from_buff(xdp, frame))
				goto err_xdp;
			break;
		case XDP_TX:
			orig_frame = *frame;
			xdp->rxq->mem = frame->mem;
			if (unlikely(veth_xdp_tx(rq, xdp, bq) < 0)) {
				trace_xdp_exception(rq->dev, xdp_prog, act);
				frame = &orig_frame;
				stats->rx_drops++;
				goto err_xdp;
			}
			stats->xdp_tx++;
			rcu_read_unlock();
			goto xdp_xmit;
		case XDP_REDIRECT:
			orig_frame = *frame;
			xdp->rxq->mem = frame->mem;
			if (xdp_do_redirect(rq->dev, xdp, xdp_prog)) {
				frame = &orig_frame;
				stats->rx_drops++;
				goto err_xdp;
			}
			stats->xdp_redirect++;
			rcu_read_unlock();
			goto xdp_xmit;
		default:
			bpf_warn_invalid_xdp_action(rq->dev, xdp_prog, act);
			fallthrough;
		case XDP_ABORTED:
			trace_xdp_exception(rq->dev, xdp_prog, act);
			fallthrough;
		case XDP_DROP:
			stats->xdp_drops++;
			goto err_xdp;
		}
	}
	rcu_read_unlock();

	return frame;
err_xdp:
	rcu_read_unlock();
	xdp_return_frame(frame);
xdp_xmit:
	return NULL;
}

/* frames array contains VETH_XDP_BATCH at most */
static void veth_xdp_rcv_bulk_skb(struct veth_rq *rq, void **frames,
				  int n_xdpf, struct veth_xdp_tx_bq *bq,
				  struct veth_stats *stats)
{
	void *skbs[VETH_XDP_BATCH];
	int i;

	if (xdp_alloc_skb_bulk(skbs, n_xdpf,
			       GFP_ATOMIC | __GFP_ZERO) < 0) {
		for (i = 0; i < n_xdpf; i++)
			xdp_return_frame(frames[i]);
		stats->rx_drops += n_xdpf;

		return;
	}

	for (i = 0; i < n_xdpf; i++) {
		struct sk_buff *skb = skbs[i];

		skb = __xdp_build_skb_from_frame(frames[i], skb,
						 rq->dev);
		if (!skb) {
			xdp_return_frame(frames[i]);
			stats->rx_drops++;
			continue;
		}
		napi_gro_receive(&rq->xdp_napi, skb);
	}
}

static void veth_xdp_get(struct xdp_buff *xdp)
{
	struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(xdp);
	int i;

	get_page(virt_to_page(xdp->data));
	if (likely(!xdp_buff_has_frags(xdp)))
		return;

	for (i = 0; i < sinfo->nr_frags; i++)
		__skb_frag_ref(&sinfo->frags[i]);
}

static int veth_convert_skb_to_xdp_buff(struct veth_rq *rq,
					struct xdp_buff *xdp,
					struct sk_buff **pskb)
{
	struct sk_buff *skb = *pskb;
	u32 frame_sz;

	if (skb_shared(skb) || skb_head_is_locked(skb) ||
	    skb_shinfo(skb)->nr_frags ||
	    skb_headroom(skb) < XDP_PACKET_HEADROOM) {
		u32 size, len, max_head_size, off;
		struct sk_buff *nskb;
		struct page *page;
		int i, head_off;

		/* We need a private copy of the skb and data buffers since
		 * the ebpf program can modify it. We segment the original skb
		 * into order-0 pages without linearize it.
		 *
		 * Make sure we have enough space for linear and paged area
		 */
		max_head_size = SKB_WITH_OVERHEAD(PAGE_SIZE -
						  VETH_XDP_HEADROOM);
		if (skb->len > PAGE_SIZE * MAX_SKB_FRAGS + max_head_size)
			goto drop;

		/* Allocate skb head */
		page = page_pool_dev_alloc_pages(rq->page_pool);
		if (!page)
			goto drop;

		nskb = napi_build_skb(page_address(page), PAGE_SIZE);
		if (!nskb) {
			page_pool_put_full_page(rq->page_pool, page, true);
			goto drop;
		}

		skb_reserve(nskb, VETH_XDP_HEADROOM);
		skb_copy_header(nskb, skb);
		skb_mark_for_recycle(nskb);

		size = min_t(u32, skb->len, max_head_size);
		if (skb_copy_bits(skb, 0, nskb->data, size)) {
			consume_skb(nskb);
			goto drop;
		}
		skb_put(nskb, size);

		head_off = skb_headroom(nskb) - skb_headroom(skb);
		skb_headers_offset_update(nskb, head_off);

		/* Allocate paged area of new skb */
		off = size;
		len = skb->len - off;

		for (i = 0; i < MAX_SKB_FRAGS && off < skb->len; i++) {
			page = page_pool_dev_alloc_pages(rq->page_pool);
			if (!page) {
				consume_skb(nskb);
				goto drop;
			}

			size = min_t(u32, len, PAGE_SIZE);
			skb_add_rx_frag(nskb, i, page, 0, size, PAGE_SIZE);
			if (skb_copy_bits(skb, off, page_address(page),
					  size)) {
				consume_skb(nskb);
				goto drop;
			}

			len -= size;
			off += size;
		}

		consume_skb(skb);
		skb = nskb;
	}

	/* SKB "head" area always have tailroom for skb_shared_info */
	frame_sz = skb_end_pointer(skb) - skb->head;
	frame_sz += SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
	xdp_init_buff(xdp, frame_sz, &rq->xdp_rxq);
	xdp_prepare_buff(xdp, skb->head, skb_headroom(skb),
			 skb_headlen(skb), true);

	if (skb_is_nonlinear(skb)) {
		skb_shinfo(skb)->xdp_frags_size = skb->data_len;
		xdp_buff_set_frags_flag(xdp);
	} else {
		xdp_buff_clear_frags_flag(xdp);
	}
	*pskb = skb;

	return 0;
drop:
	consume_skb(skb);
	*pskb = NULL;

	return -ENOMEM;
}

static struct sk_buff *veth_xdp_rcv_skb(struct veth_rq *rq,
					struct sk_buff *skb,
					struct veth_xdp_tx_bq *bq,
					struct veth_stats *stats)
{
	void *orig_data, *orig_data_end;
	struct bpf_prog *xdp_prog;
	struct veth_xdp_buff vxbuf;
	struct xdp_buff *xdp = &vxbuf.xdp;
	u32 act, metalen;
	int off;

	skb_prepare_for_gro(skb);

	rcu_read_lock();
	xdp_prog = rcu_dereference(rq->xdp_prog);
	if (unlikely(!xdp_prog)) {
		rcu_read_unlock();
		goto out;
	}

	__skb_push(skb, skb->data - skb_mac_header(skb));
	if (veth_convert_skb_to_xdp_buff(rq, xdp, &skb))
		goto drop;
	vxbuf.skb = skb;

	orig_data = xdp->data;
	orig_data_end = xdp->data_end;

	act = bpf_prog_run_xdp(xdp_prog, xdp);

	switch (act) {
	case XDP_PASS:
		break;
	case XDP_TX:
		veth_xdp_get(xdp);
		consume_skb(skb);
		xdp->rxq->mem = rq->xdp_mem;
		if (unlikely(veth_xdp_tx(rq, xdp, bq) < 0)) {
			trace_xdp_exception(rq->dev, xdp_prog, act);
			stats->rx_drops++;
			goto err_xdp;
		}
		stats->xdp_tx++;
		rcu_read_unlock();
		goto xdp_xmit;
	case XDP_REDIRECT:
		veth_xdp_get(xdp);
		consume_skb(skb);
		xdp->rxq->mem = rq->xdp_mem;
		if (xdp_do_redirect(rq->dev, xdp, xdp_prog)) {
			stats->rx_drops++;
			goto err_xdp;
		}
		stats->xdp_redirect++;
		rcu_read_unlock();
		goto xdp_xmit;
	default:
		bpf_warn_invalid_xdp_action(rq->dev, xdp_prog, act);
		fallthrough;
	case XDP_ABORTED:
		trace_xdp_exception(rq->dev, xdp_prog, act);
		fallthrough;
	case XDP_DROP:
		stats->xdp_drops++;
		goto xdp_drop;
	}
	rcu_read_unlock();

	/* check if bpf_xdp_adjust_head was used */
	off = orig_data - xdp->data;
	if (off > 0)
		__skb_push(skb, off);
	else if (off < 0)
		__skb_pull(skb, -off);

	skb_reset_mac_header(skb);

	/* check if bpf_xdp_adjust_tail was used */
	off = xdp->data_end - orig_data_end;
	if (off != 0)
		__skb_put(skb, off); /* positive on grow, negative on shrink */

	/* XDP frag metadata (e.g. nr_frags) are updated in eBPF helpers
	 * (e.g. bpf_xdp_adjust_tail), we need to update data_len here.
	 */
	if (xdp_buff_has_frags(xdp))
		skb->data_len = skb_shinfo(skb)->xdp_frags_size;
	else
		skb->data_len = 0;

	skb->protocol = eth_type_trans(skb, rq->dev);

	metalen = xdp->data - xdp->data_meta;
	if (metalen)
		skb_metadata_set(skb, metalen);
out:
	return skb;
drop:
	stats->rx_drops++;
xdp_drop:
	rcu_read_unlock();
	kfree_skb(skb);
	return NULL;
err_xdp:
	rcu_read_unlock();
	xdp_return_buff(xdp);
xdp_xmit:
	return NULL;
}

static int veth_xdp_rcv(struct veth_rq *rq, int budget,
			struct veth_xdp_tx_bq *bq,
			struct veth_stats *stats)
{
	int i, done = 0, n_xdpf = 0;
	void *xdpf[VETH_XDP_BATCH];

	for (i = 0; i < budget; i++) {
		void *ptr = __ptr_ring_consume(&rq->xdp_ring);

		if (!ptr)
			break;

		if (veth_is_xdp_frame(ptr)) {
			/* ndo_xdp_xmit */
			struct xdp_frame *frame = veth_ptr_to_xdp(ptr);

			stats->xdp_bytes += xdp_get_frame_len(frame);
			frame = veth_xdp_rcv_one(rq, frame, bq, stats);
			if (frame) {
				/* XDP_PASS */
				xdpf[n_xdpf++] = frame;
				if (n_xdpf == VETH_XDP_BATCH) {
					veth_xdp_rcv_bulk_skb(rq, xdpf, n_xdpf,
							      bq, stats);
					n_xdpf = 0;
				}
			}
		} else {
			/* ndo_start_xmit */
			struct sk_buff *skb = ptr;

			stats->xdp_bytes += skb->len;
			skb = veth_xdp_rcv_skb(rq, skb, bq, stats);
			if (skb) {
				if (skb_shared(skb) || skb_unclone(skb, GFP_ATOMIC))
					netif_receive_skb(skb);
				else
					napi_gro_receive(&rq->xdp_napi, skb);
			}
		}
		done++;
	}

	if (n_xdpf)
		veth_xdp_rcv_bulk_skb(rq, xdpf, n_xdpf, bq, stats);

	u64_stats_update_begin(&rq->stats.syncp);
	rq->stats.vs.xdp_redirect += stats->xdp_redirect;
	rq->stats.vs.xdp_bytes += stats->xdp_bytes;
	rq->stats.vs.xdp_drops += stats->xdp_drops;
	rq->stats.vs.rx_drops += stats->rx_drops;
	rq->stats.vs.xdp_packets += done;
	u64_stats_update_end(&rq->stats.syncp);

	return done;
}

static int veth_poll(struct napi_struct *napi, int budget)
{
	struct veth_rq *rq =
		container_of(napi, struct veth_rq, xdp_napi);
	struct veth_stats stats = {};
	struct veth_xdp_tx_bq bq;
	int done;

	bq.count = 0;

	xdp_set_return_frame_no_direct();
	done = veth_xdp_rcv(rq, budget, &bq, &stats);

	if (stats.xdp_redirect > 0)
		xdp_do_flush();

	if (done < budget && napi_complete_done(napi, done)) {
		/* Write rx_notify_masked before reading ptr_ring */
		smp_store_mb(rq->rx_notify_masked, false);
		if (unlikely(!__ptr_ring_empty(&rq->xdp_ring))) {
			if (napi_schedule_prep(&rq->xdp_napi)) {
				WRITE_ONCE(rq->rx_notify_masked, true);
				__napi_schedule(&rq->xdp_napi);
			}
		}
	}

	if (stats.xdp_tx > 0)
		veth_xdp_flush(rq, &bq);
	xdp_clear_return_frame_no_direct();

	return done;
}

static int veth_create_page_pool(struct veth_rq *rq)
{
	struct page_pool_params pp_params = {
		.order = 0,
		.pool_size = VETH_RING_SIZE,
		.nid = NUMA_NO_NODE,
		.dev = &rq->dev->dev,
	};

	rq->page_pool = page_pool_create(&pp_params);
	if (IS_ERR(rq->page_pool)) {
		int err = PTR_ERR(rq->page_pool);

		rq->page_pool = NULL;
		return err;
	}

	return 0;
}

static int __veth_napi_enable_range(struct net_device *dev, int start, int end)
{
	struct veth_priv *priv = netdev_priv(dev);
	int err, i;

	for (i = start; i < end; i++) {
		err = veth_create_page_pool(&priv->rq[i]);
		if (err)
			goto err_page_pool;
	}

	for (i = start; i < end; i++) {
		struct veth_rq *rq = &priv->rq[i];

		err = ptr_ring_init(&rq->xdp_ring, VETH_RING_SIZE, GFP_KERNEL);
		if (err)
			goto err_xdp_ring;
	}

	for (i = start; i < end; i++) {
		struct veth_rq *rq = &priv->rq[i];

		napi_enable(&rq->xdp_napi);
		rcu_assign_pointer(priv->rq[i].napi, &priv->rq[i].xdp_napi);
	}

	return 0;

err_xdp_ring:
	for (i--; i >= start; i--)
		ptr_ring_cleanup(&priv->rq[i].xdp_ring, veth_ptr_free);
	i = end;
err_page_pool:
	for (i--; i >= start; i--) {
		page_pool_destroy(priv->rq[i].page_pool);
		priv->rq[i].page_pool = NULL;
	}

	return err;
}

static int __veth_napi_enable(struct net_device *dev)
{
	return __veth_napi_enable_range(dev, 0, dev->real_num_rx_queues);
}

static void veth_napi_del_range(struct net_device *dev, int start, int end)
{
	struct veth_priv *priv = netdev_priv(dev);
	int i;

	for (i = start; i < end; i++) {
		struct veth_rq *rq = &priv->rq[i];

		rcu_assign_pointer(priv->rq[i].napi, NULL);
		napi_disable(&rq->xdp_napi);
		__netif_napi_del(&rq->xdp_napi);
	}
	synchronize_net();

	for (i = start; i < end; i++) {
		struct veth_rq *rq = &priv->rq[i];

		rq->rx_notify_masked = false;
		ptr_ring_cleanup(&rq->xdp_ring, veth_ptr_free);
	}

	for (i = start; i < end; i++) {
		page_pool_destroy(priv->rq[i].page_pool);
		priv->rq[i].page_pool = NULL;
	}
}

static void veth_napi_del(struct net_device *dev)
{
	veth_napi_del_range(dev, 0, dev->real_num_rx_queues);
}

static bool veth_gro_requested(const struct net_device *dev)
{
	return !!(dev->wanted_features & NETIF_F_GRO);
}

static int veth_enable_xdp_range(struct net_device *dev, int start, int end,
				 bool napi_already_on)
{
	struct veth_priv *priv = netdev_priv(dev);
	int err, i;

	for (i = start; i < end; i++) {
		struct veth_rq *rq = &priv->rq[i];

		if (!napi_already_on)
			netif_napi_add(dev, &rq->xdp_napi, veth_poll);
		err = xdp_rxq_info_reg(&rq->xdp_rxq, dev, i, rq->xdp_napi.napi_id);
		if (err < 0)
			goto err_rxq_reg;

		err = xdp_rxq_info_reg_mem_model(&rq->xdp_rxq,
						 MEM_TYPE_PAGE_SHARED,
						 NULL);
		if (err < 0)
			goto err_reg_mem;

		/* Save original mem info as it can be overwritten */
		rq->xdp_mem = rq->xdp_rxq.mem;
	}
	return 0;

err_reg_mem:
	xdp_rxq_info_unreg(&priv->rq[i].xdp_rxq);
err_rxq_reg:
	for (i--; i >= start; i--) {
		struct veth_rq *rq = &priv->rq[i];

		xdp_rxq_info_unreg(&rq->xdp_rxq);
		if (!napi_already_on)
			netif_napi_del(&rq->xdp_napi);
	}

	return err;
}

static void veth_disable_xdp_range(struct net_device *dev, int start, int end,
				   bool delete_napi)
{
	struct veth_priv *priv = netdev_priv(dev);
	int i;

	for (i = start; i < end; i++) {
		struct veth_rq *rq = &priv->rq[i];

		rq->xdp_rxq.mem = rq->xdp_mem;
		xdp_rxq_info_unreg(&rq->xdp_rxq);

		if (delete_napi)
			netif_napi_del(&rq->xdp_napi);
	}
}

static int veth_enable_xdp(struct net_device *dev)
{
	bool napi_already_on = veth_gro_requested(dev) && (dev->flags & IFF_UP);
	struct veth_priv *priv = netdev_priv(dev);
	int err, i;

	if (!xdp_rxq_info_is_reg(&priv->rq[0].xdp_rxq)) {
		err = veth_enable_xdp_range(dev, 0, dev->real_num_rx_queues, napi_already_on);
		if (err)
			return err;

		if (!napi_already_on) {
			err = __veth_napi_enable(dev);
			if (err) {
				veth_disable_xdp_range(dev, 0, dev->real_num_rx_queues, true);
				return err;
			}

			if (!veth_gro_requested(dev)) {
				/* user-space did not require GRO, but adding XDP
				 * is supposed to get GRO working
				 */
				dev->features |= NETIF_F_GRO;
				netdev_features_change(dev);
			}
		}
	}

	for (i = 0; i < dev->real_num_rx_queues; i++) {
		rcu_assign_pointer(priv->rq[i].xdp_prog, priv->_xdp_prog);
		rcu_assign_pointer(priv->rq[i].napi, &priv->rq[i].xdp_napi);
	}

	return 0;
}

static void veth_disable_xdp(struct net_device *dev)
{
	struct veth_priv *priv = netdev_priv(dev);
	int i;

	for (i = 0; i < dev->real_num_rx_queues; i++)
		rcu_assign_pointer(priv->rq[i].xdp_prog, NULL);

	if (!netif_running(dev) || !veth_gro_requested(dev)) {
		veth_napi_del(dev);

		/* if user-space did not require GRO, since adding XDP
		 * enabled it, clear it now
		 */
		if (!veth_gro_requested(dev) && netif_running(dev)) {
			dev->features &= ~NETIF_F_GRO;
			netdev_features_change(dev);
		}
	}

	veth_disable_xdp_range(dev, 0, dev->real_num_rx_queues, false);
}

static int veth_napi_enable_range(struct net_device *dev, int start, int end)
{
	struct veth_priv *priv = netdev_priv(dev);
	int err, i;

	for (i = start; i < end; i++) {
		struct veth_rq *rq = &priv->rq[i];

		netif_napi_add(dev, &rq->xdp_napi, veth_poll);
	}

	err = __veth_napi_enable_range(dev, start, end);
	if (err) {
		for (i = start; i < end; i++) {
			struct veth_rq *rq = &priv->rq[i];

			netif_napi_del(&rq->xdp_napi);
		}
		return err;
	}
	return err;
}

static int veth_napi_enable(struct net_device *dev)
{
	return veth_napi_enable_range(dev, 0, dev->real_num_rx_queues);
}

static void veth_disable_range_safe(struct net_device *dev, int start, int end)
{
	struct veth_priv *priv = netdev_priv(dev);

	if (start >= end)
		return;

	if (priv->_xdp_prog) {
		veth_napi_del_range(dev, start, end);
		veth_disable_xdp_range(dev, start, end, false);
	} else if (veth_gro_requested(dev)) {
		veth_napi_del_range(dev, start, end);
	}
}

static int veth_enable_range_safe(struct net_device *dev, int start, int end)
{
	struct veth_priv *priv = netdev_priv(dev);
	int err;

	if (start >= end)
		return 0;

	if (priv->_xdp_prog) {
		/* these channels are freshly initialized, napi is not on there even
		 * when GRO is requeste
		 */
		err = veth_enable_xdp_range(dev, start, end, false);
		if (err)
			return err;

		err = __veth_napi_enable_range(dev, start, end);
		if (err) {
			/* on error always delete the newly added napis */
			veth_disable_xdp_range(dev, start, end, true);
			return err;
		}
	} else if (veth_gro_requested(dev)) {
		return veth_napi_enable_range(dev, start, end);
	}
	return 0;
}

static void veth_set_xdp_features(struct net_device *dev)
{
	struct veth_priv *priv = netdev_priv(dev);
	struct net_device *peer;

	peer = rtnl_dereference(priv->peer);
	if (peer && peer->real_num_tx_queues <= dev->real_num_rx_queues) {
		struct veth_priv *priv_peer = netdev_priv(peer);
		xdp_features_t val = NETDEV_XDP_ACT_BASIC |
				     NETDEV_XDP_ACT_REDIRECT |
				     NETDEV_XDP_ACT_RX_SG;

		if (priv_peer->_xdp_prog || veth_gro_requested(peer))
			val |= NETDEV_XDP_ACT_NDO_XMIT |
			       NETDEV_XDP_ACT_NDO_XMIT_SG;
		xdp_set_features_flag(dev, val);
	} else {
		xdp_clear_features_flag(dev);
	}
}

static int veth_set_channels(struct net_device *dev,
			     struct ethtool_channels *ch)
{
	struct veth_priv *priv = netdev_priv(dev);
	unsigned int old_rx_count, new_rx_count;
	struct veth_priv *peer_priv;
	struct net_device *peer;
	int err;

	/* sanity check. Upper bounds are already enforced by the caller */
	if (!ch->rx_count || !ch->tx_count)
		return -EINVAL;

	/* avoid braking XDP, if that is enabled */
	peer = rtnl_dereference(priv->peer);
	peer_priv = peer ? netdev_priv(peer) : NULL;
	if (priv->_xdp_prog && peer && ch->rx_count < peer->real_num_tx_queues)
		return -EINVAL;

	if (peer && peer_priv && peer_priv->_xdp_prog && ch->tx_count > peer->real_num_rx_queues)
		return -EINVAL;

	old_rx_count = dev->real_num_rx_queues;
	new_rx_count = ch->rx_count;
	if (netif_running(dev)) {
		/* turn device off */
		netif_carrier_off(dev);
		if (peer)
			netif_carrier_off(peer);

		/* try to allocate new resurces, as needed*/
		err = veth_enable_range_safe(dev, old_rx_count, new_rx_count);
		if (err)
			goto out;
	}

	err = netif_set_real_num_rx_queues(dev, ch->rx_count);
	if (err)
		goto revert;

	err = netif_set_real_num_tx_queues(dev, ch->tx_count);
	if (err) {
		int err2 = netif_set_real_num_rx_queues(dev, old_rx_count);

		/* this error condition could happen only if rx and tx change
		 * in opposite directions (e.g. tx nr raises, rx nr decreases)
		 * and we can't do anything to fully restore the original
		 * status
		 */
		if (err2)
			pr_warn("Can't restore rx queues config %d -> %d %d",
				new_rx_count, old_rx_count, err2);
		else
			goto revert;
	}

out:
	if (netif_running(dev)) {
		/* note that we need to swap the arguments WRT the enable part
		 * to identify the range we have to disable
		 */
		veth_disable_range_safe(dev, new_rx_count, old_rx_count);
		netif_carrier_on(dev);
		if (peer)
			netif_carrier_on(peer);
	}

	/* update XDP supported features */
	veth_set_xdp_features(dev);
	if (peer)
		veth_set_xdp_features(peer);

	return err;

revert:
	new_rx_count = old_rx_count;
	old_rx_count = ch->rx_count;
	goto out;
}

static int veth_open(struct net_device *dev)
{
	struct veth_priv *priv = netdev_priv(dev);
	struct net_device *peer = rtnl_dereference(priv->peer);
	int err;

	if (!peer)
		return -ENOTCONN;

	if (priv->_xdp_prog) {
		err = veth_enable_xdp(dev);
		if (err)
			return err;
	} else if (veth_gro_requested(dev)) {
		err = veth_napi_enable(dev);
		if (err)
			return err;
	}

	if (peer->flags & IFF_UP) {
		netif_carrier_on(dev);
		netif_carrier_on(peer);
	}

	return 0;
}

static int veth_close(struct net_device *dev)
{
	struct veth_priv *priv = netdev_priv(dev);
	struct net_device *peer = rtnl_dereference(priv->peer);

	netif_carrier_off(dev);
	if (peer)
		netif_carrier_off(peer);

	if (priv->_xdp_prog)
		veth_disable_xdp(dev);
	else if (veth_gro_requested(dev))
		veth_napi_del(dev);

	return 0;
}

static int is_valid_veth_mtu(int mtu)
{
	return mtu >= ETH_MIN_MTU && mtu <= ETH_MAX_MTU;
}

static int veth_alloc_queues(struct net_device *dev)
{
	struct veth_priv *priv = netdev_priv(dev);
	int i;

	priv->rq = kcalloc(dev->num_rx_queues, sizeof(*priv->rq), GFP_KERNEL_ACCOUNT);
	if (!priv->rq)
		return -ENOMEM;

	for (i = 0; i < dev->num_rx_queues; i++) {
		priv->rq[i].dev = dev;
		u64_stats_init(&priv->rq[i].stats.syncp);
	}

	return 0;
}

static void veth_free_queues(struct net_device *dev)
{
	struct veth_priv *priv = netdev_priv(dev);

	kfree(priv->rq);
}

static int veth_dev_init(struct net_device *dev)
{
	int err;

	dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats);
	if (!dev->lstats)
		return -ENOMEM;

	err = veth_alloc_queues(dev);
	if (err) {
		free_percpu(dev->lstats);
		return err;
	}

	return 0;
}

static void veth_dev_free(struct net_device *dev)
{
	veth_free_queues(dev);
	free_percpu(dev->lstats);
}

#ifdef CONFIG_NET_POLL_CONTROLLER
static void veth_poll_controller(struct net_device *dev)
{
	/* veth only receives frames when its peer sends one
	 * Since it has nothing to do with disabling irqs, we are guaranteed
	 * never to have pending data when we poll for it so
	 * there is nothing to do here.
	 *
	 * We need this though so netpoll recognizes us as an interface that
	 * supports polling, which enables bridge devices in virt setups to
	 * still use netconsole
	 */
}
#endif	/* CONFIG_NET_POLL_CONTROLLER */

static int veth_get_iflink(const struct net_device *dev)
{
	struct veth_priv *priv = netdev_priv(dev);
	struct net_device *peer;
	int iflink;

	rcu_read_lock();
	peer = rcu_dereference(priv->peer);
	iflink = peer ? peer->ifindex : 0;
	rcu_read_unlock();

	return iflink;
}

static netdev_features_t veth_fix_features(struct net_device *dev,
					   netdev_features_t features)
{
	struct veth_priv *priv = netdev_priv(dev);
	struct net_device *peer;

	peer = rtnl_dereference(priv->peer);
	if (peer) {
		struct veth_priv *peer_priv = netdev_priv(peer);

		if (peer_priv->_xdp_prog)
			features &= ~NETIF_F_GSO_SOFTWARE;
	}
	if (priv->_xdp_prog)
		features |= NETIF_F_GRO;

	return features;
}

static int veth_set_features(struct net_device *dev,
			     netdev_features_t features)
{
	netdev_features_t changed = features ^ dev->features;
	struct veth_priv *priv = netdev_priv(dev);
	struct net_device *peer;
	int err;

	if (!(changed & NETIF_F_GRO) || !(dev->flags & IFF_UP) || priv->_xdp_prog)
		return 0;

	peer = rtnl_dereference(priv->peer);
	if (features & NETIF_F_GRO) {
		err = veth_napi_enable(dev);
		if (err)
			return err;

		if (peer)
			xdp_features_set_redirect_target(peer, true);
	} else {
		if (peer)
			xdp_features_clear_redirect_target(peer);
		veth_napi_del(dev);
	}
	return 0;
}

static void veth_set_rx_headroom(struct net_device *dev, int new_hr)
{
	struct veth_priv *peer_priv, *priv = netdev_priv(dev);
	struct net_device *peer;

	if (new_hr < 0)
		new_hr = 0;

	rcu_read_lock();
	peer = rcu_dereference(priv->peer);
	if (unlikely(!peer))
		goto out;

	peer_priv = netdev_priv(peer);
	priv->requested_headroom = new_hr;
	new_hr = max(priv->requested_headroom, peer_priv->requested_headroom);
	dev->needed_headroom = new_hr;
	peer->needed_headroom = new_hr;

out:
	rcu_read_unlock();
}

static int veth_xdp_set(struct net_device *dev, struct bpf_prog *prog,
			struct netlink_ext_ack *extack)
{
	struct veth_priv *priv = netdev_priv(dev);
	struct bpf_prog *old_prog;
	struct net_device *peer;
	unsigned int max_mtu;
	int err;

	old_prog = priv->_xdp_prog;
	priv->_xdp_prog = prog;
	peer = rtnl_dereference(priv->peer);

	if (prog) {
		if (!peer) {
			NL_SET_ERR_MSG_MOD(extack, "Cannot set XDP when peer is detached");
			err = -ENOTCONN;
			goto err;
		}

		max_mtu = SKB_WITH_OVERHEAD(PAGE_SIZE - VETH_XDP_HEADROOM) -
			  peer->hard_header_len;
		/* Allow increasing the max_mtu if the program supports
		 * XDP fragments.
		 */
		if (prog->aux->xdp_has_frags)
			max_mtu += PAGE_SIZE * MAX_SKB_FRAGS;

		if (peer->mtu > max_mtu) {
			NL_SET_ERR_MSG_MOD(extack, "Peer MTU is too large to set XDP");
			err = -ERANGE;
			goto err;
		}

		if (dev->real_num_rx_queues < peer->real_num_tx_queues) {
			NL_SET_ERR_MSG_MOD(extack, "XDP expects number of rx queues not less than peer tx queues");
			err = -ENOSPC;
			goto err;
		}

		if (dev->flags & IFF_UP) {
			err = veth_enable_xdp(dev);
			if (err) {
				NL_SET_ERR_MSG_MOD(extack, "Setup for XDP failed");
				goto err;
			}
		}

		if (!old_prog) {
			peer->hw_features &= ~NETIF_F_GSO_SOFTWARE;
			peer->max_mtu = max_mtu;
		}

		xdp_features_set_redirect_target(peer, true);
	}

	if (old_prog) {
		if (!prog) {
			if (peer && !veth_gro_requested(dev))
				xdp_features_clear_redirect_target(peer);

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

			if (peer) {
				peer->hw_features |= NETIF_F_GSO_SOFTWARE;
				peer->max_mtu = ETH_MAX_MTU;
			}
		}
		bpf_prog_put(old_prog);
	}

	if ((!!old_prog ^ !!prog) && peer)
		netdev_update_features(peer);

	return 0;
err:
	priv->_xdp_prog = old_prog;

	return err;
}

static int veth_xdp(struct net_device *dev, struct netdev_bpf *xdp)
{
	switch (xdp->command) {
	case XDP_SETUP_PROG:
		return veth_xdp_set(dev, xdp->prog, xdp->extack);
	default:
		return -EINVAL;
	}
}

static int veth_xdp_rx_timestamp(const struct xdp_md *ctx, u64 *timestamp)
{
	struct veth_xdp_buff *_ctx = (void *)ctx;

	if (!_ctx->skb)
		return -ENODATA;

	*timestamp = skb_hwtstamps(_ctx->skb)->hwtstamp;
	return 0;
}

static int veth_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash,
			    enum xdp_rss_hash_type *rss_type)
{
	struct veth_xdp_buff *_ctx = (void *)ctx;
	struct sk_buff *skb = _ctx->skb;

	if (!skb)
		return -ENODATA;

	*hash = skb_get_hash(skb);
	*rss_type = skb->l4_hash ? XDP_RSS_TYPE_L4_ANY : XDP_RSS_TYPE_NONE;

	return 0;
}

static const struct net_device_ops veth_netdev_ops = {
	.ndo_init            = veth_dev_init,
	.ndo_open            = veth_open,
	.ndo_stop            = veth_close,
	.ndo_start_xmit      = veth_xmit,
	.ndo_get_stats64     = veth_get_stats64,
	.ndo_set_rx_mode     = veth_set_multicast_list,
	.ndo_set_mac_address = eth_mac_addr,
#ifdef CONFIG_NET_POLL_CONTROLLER
	.ndo_poll_controller	= veth_poll_controller,
#endif
	.ndo_get_iflink		= veth_get_iflink,
	.ndo_fix_features	= veth_fix_features,
	.ndo_set_features	= veth_set_features,
	.ndo_features_check	= passthru_features_check,
	.ndo_set_rx_headroom	= veth_set_rx_headroom,
	.ndo_bpf		= veth_xdp,
	.ndo_xdp_xmit		= veth_ndo_xdp_xmit,
	.ndo_get_peer_dev	= veth_peer_dev,
};

static const struct xdp_metadata_ops veth_xdp_metadata_ops = {
	.xmo_rx_timestamp		= veth_xdp_rx_timestamp,
	.xmo_rx_hash			= veth_xdp_rx_hash,
};

#define VETH_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HW_CSUM | \
		       NETIF_F_RXCSUM | NETIF_F_SCTP_CRC | NETIF_F_HIGHDMA | \
		       NETIF_F_GSO_SOFTWARE | NETIF_F_GSO_ENCAP_ALL | \
		       NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX | \
		       NETIF_F_HW_VLAN_STAG_TX | NETIF_F_HW_VLAN_STAG_RX )

static void veth_setup(struct net_device *dev)
{
	ether_setup(dev);

	dev->priv_flags &= ~IFF_TX_SKB_SHARING;
	dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
	dev->priv_flags |= IFF_NO_QUEUE;
	dev->priv_flags |= IFF_PHONY_HEADROOM;

	dev->netdev_ops = &veth_netdev_ops;
	dev->xdp_metadata_ops = &veth_xdp_metadata_ops;
	dev->ethtool_ops = &veth_ethtool_ops;
	dev->features |= NETIF_F_LLTX;
	dev->features |= VETH_FEATURES;
	dev->vlan_features = dev->features &
			     ~(NETIF_F_HW_VLAN_CTAG_TX |
			       NETIF_F_HW_VLAN_STAG_TX |
			       NETIF_F_HW_VLAN_CTAG_RX |
			       NETIF_F_HW_VLAN_STAG_RX);
	dev->needs_free_netdev = true;
	dev->priv_destructor = veth_dev_free;
	dev->max_mtu = ETH_MAX_MTU;

	dev->hw_features = VETH_FEATURES;
	dev->hw_enc_features = VETH_FEATURES;
	dev->mpls_features = NETIF_F_HW_CSUM | NETIF_F_GSO_SOFTWARE;
	netif_set_tso_max_size(dev, GSO_MAX_SIZE);
}

/*
 * netlink interface
 */

static int veth_validate(struct nlattr *tb[], struct nlattr *data[],
			 struct netlink_ext_ack *extack)
{
	if (tb[IFLA_ADDRESS]) {
		if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
			return -EINVAL;
		if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
			return -EADDRNOTAVAIL;
	}
	if (tb[IFLA_MTU]) {
		if (!is_valid_veth_mtu(nla_get_u32(tb[IFLA_MTU])))
			return -EINVAL;
	}
	return 0;
}

static struct rtnl_link_ops veth_link_ops;

static void veth_disable_gro(struct net_device *dev)
{
	dev->features &= ~NETIF_F_GRO;
	dev->wanted_features &= ~NETIF_F_GRO;
	netdev_update_features(dev);
}

static int veth_init_queues(struct net_device *dev, struct nlattr *tb[])
{
	int err;

	if (!tb[IFLA_NUM_TX_QUEUES] && dev->num_tx_queues > 1) {
		err = netif_set_real_num_tx_queues(dev, 1);
		if (err)
			return err;
	}
	if (!tb[IFLA_NUM_RX_QUEUES] && dev->num_rx_queues > 1) {
		err = netif_set_real_num_rx_queues(dev, 1);
		if (err)
			return err;
	}
	return 0;
}

static int veth_newlink(struct net *src_net, struct net_device *dev,
			struct nlattr *tb[], struct nlattr *data[],
			struct netlink_ext_ack *extack)
{
	int err;
	struct net_device *peer;
	struct veth_priv *priv;
	char ifname[IFNAMSIZ];
	struct nlattr *peer_tb[IFLA_MAX + 1], **tbp;
	unsigned char name_assign_type;
	struct ifinfomsg *ifmp;
	struct net *net;

	/*
	 * create and register peer first
	 */
	if (data != NULL && data[VETH_INFO_PEER] != NULL) {
		struct nlattr *nla_peer;

		nla_peer = data[VETH_INFO_PEER];
		ifmp = nla_data(nla_peer);
		err = rtnl_nla_parse_ifinfomsg(peer_tb, nla_peer, extack);
		if (err < 0)
			return err;

		err = veth_validate(peer_tb, NULL, extack);
		if (err < 0)
			return err;

		tbp = peer_tb;
	} else {
		ifmp = NULL;
		tbp = tb;
	}

	if (ifmp && tbp[IFLA_IFNAME]) {
		nla_strscpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ);
		name_assign_type = NET_NAME_USER;
	} else {
		snprintf(ifname, IFNAMSIZ, DRV_NAME "%%d");
		name_assign_type = NET_NAME_ENUM;
	}

	net = rtnl_link_get_net(src_net, tbp);
	if (IS_ERR(net))
		return PTR_ERR(net);

	peer = rtnl_create_link(net, ifname, name_assign_type,
				&veth_link_ops, tbp, extack);
	if (IS_ERR(peer)) {
		put_net(net);
		return PTR_ERR(peer);
	}

	if (!ifmp || !tbp[IFLA_ADDRESS])
		eth_hw_addr_random(peer);

	if (ifmp && (dev->ifindex != 0))
		peer->ifindex = ifmp->ifi_index;

	netif_inherit_tso_max(peer, dev);

	err = register_netdevice(peer);
	put_net(net);
	net = NULL;
	if (err < 0)
		goto err_register_peer;

	/* keep GRO disabled by default to be consistent with the established
	 * veth behavior
	 */
	veth_disable_gro(peer);
	netif_carrier_off(peer);

	err = rtnl_configure_link(peer, ifmp, 0, NULL);
	if (err < 0)
		goto err_configure_peer;

	/*
	 * register dev last
	 *
	 * note, that since we've registered new device the dev's name
	 * should be re-allocated
	 */

	if (tb[IFLA_ADDRESS] == NULL)
		eth_hw_addr_random(dev);

	if (tb[IFLA_IFNAME])
		nla_strscpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ);
	else
		snprintf(dev->name, IFNAMSIZ, DRV_NAME "%%d");

	err = register_netdevice(dev);
	if (err < 0)
		goto err_register_dev;

	netif_carrier_off(dev);

	/*
	 * tie the deviced together
	 */

	priv = netdev_priv(dev);
	rcu_assign_pointer(priv->peer, peer);
	err = veth_init_queues(dev, tb);
	if (err)
		goto err_queues;

	priv = netdev_priv(peer);
	rcu_assign_pointer(priv->peer, dev);
	err = veth_init_queues(peer, tb);
	if (err)
		goto err_queues;

	veth_disable_gro(dev);
	/* update XDP supported features */
	veth_set_xdp_features(dev);
	veth_set_xdp_features(peer);

	return 0;

err_queues:
	unregister_netdevice(dev);
err_register_dev:
	/* nothing to do */
err_configure_peer:
	unregister_netdevice(peer);
	return err;

err_register_peer:
	free_netdev(peer);
	return err;
}

static void veth_dellink(struct net_device *dev, struct list_head *head)
{
	struct veth_priv *priv;
	struct net_device *peer;

	priv = netdev_priv(dev);
	peer = rtnl_dereference(priv->peer);

	/* Note : dellink() is called from default_device_exit_batch(),
	 * before a rcu_synchronize() point. The devices are guaranteed
	 * not being freed before one RCU grace period.
	 */
	RCU_INIT_POINTER(priv->peer, NULL);
	unregister_netdevice_queue(dev, head);

	if (peer) {
		priv = netdev_priv(peer);
		RCU_INIT_POINTER(priv->peer, NULL);
		unregister_netdevice_queue(peer, head);
	}
}

static const struct nla_policy veth_policy[VETH_INFO_MAX + 1] = {
	[VETH_INFO_PEER]	= { .len = sizeof(struct ifinfomsg) },
};

static struct net *veth_get_link_net(const struct net_device *dev)
{
	struct veth_priv *priv = netdev_priv(dev);
	struct net_device *peer = rtnl_dereference(priv->peer);

	return peer ? dev_net(peer) : dev_net(dev);
}

static unsigned int veth_get_num_queues(void)
{
	/* enforce the same queue limit as rtnl_create_link */
	int queues = num_possible_cpus();

	if (queues > 4096)
		queues = 4096;
	return queues;
}

static struct rtnl_link_ops veth_link_ops = {
	.kind		= DRV_NAME,
	.priv_size	= sizeof(struct veth_priv),
	.setup		= veth_setup,
	.validate	= veth_validate,
	.newlink	= veth_newlink,
	.dellink	= veth_dellink,
	.policy		= veth_policy,
	.maxtype	= VETH_INFO_MAX,
	.get_link_net	= veth_get_link_net,
	.get_num_tx_queues	= veth_get_num_queues,
	.get_num_rx_queues	= veth_get_num_queues,
};

/*
 * init/fini
 */

static __init int veth_init(void)
{
	return rtnl_link_register(&veth_link_ops);
}

static __exit void veth_exit(void)
{
	rtnl_link_unregister(&veth_link_ops);
}

module_init(veth_init);
module_exit(veth_exit);

MODULE_DESCRIPTION("Virtual Ethernet Tunnel");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS_RTNL_LINK(DRV_NAME);