aboutsummaryrefslogtreecommitdiffstats
path: root/include/linux/if_vlan.h
blob: 41a518336673b496faf7ce0ea2a65068fe6814f2 (plain) (blame)
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
/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * VLAN		An implementation of 802.1Q VLAN tagging.
 *
 * Authors:	Ben Greear <greearb@candelatech.com>
 */
#ifndef _LINUX_IF_VLAN_H_
#define _LINUX_IF_VLAN_H_

#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/rtnetlink.h>
#include <linux/bug.h>
#include <uapi/linux/if_vlan.h>

#define VLAN_HLEN	4		/* The additional bytes required by VLAN
					 * (in addition to the Ethernet header)
					 */
#define VLAN_ETH_HLEN	18		/* Total octets in header.	 */
#define VLAN_ETH_ZLEN	64		/* Min. octets in frame sans FCS */

/*
 * According to 802.3ac, the packet can be 4 bytes longer. --Klika Jan
 */
#define VLAN_ETH_DATA_LEN	1500	/* Max. octets in payload	 */
#define VLAN_ETH_FRAME_LEN	1518	/* Max. octets in frame sans FCS */

#define VLAN_MAX_DEPTH	8		/* Max. number of nested VLAN tags parsed */

/*
 * 	struct vlan_hdr - vlan header
 * 	@h_vlan_TCI: priority and VLAN ID
 *	@h_vlan_encapsulated_proto: packet type ID or len
 */
struct vlan_hdr {
	__be16	h_vlan_TCI;
	__be16	h_vlan_encapsulated_proto;
};

/**
 *	struct vlan_ethhdr - vlan ethernet header (ethhdr + vlan_hdr)
 *	@h_dest: destination ethernet address
 *	@h_source: source ethernet address
 *	@h_vlan_proto: ethernet protocol
 *	@h_vlan_TCI: priority and VLAN ID
 *	@h_vlan_encapsulated_proto: packet type ID or len
 */
struct vlan_ethhdr {
	unsigned char	h_dest[ETH_ALEN];
	unsigned char	h_source[ETH_ALEN];
	__be16		h_vlan_proto;
	__be16		h_vlan_TCI;
	__be16		h_vlan_encapsulated_proto;
};

#include <linux/skbuff.h>

static inline struct vlan_ethhdr *vlan_eth_hdr(const struct sk_buff *skb)
{
	return (struct vlan_ethhdr *)skb_mac_header(skb);
}

#define VLAN_PRIO_MASK		0xe000 /* Priority Code Point */
#define VLAN_PRIO_SHIFT		13
#define VLAN_CFI_MASK		0x1000 /* Canonical Format Indicator / Drop Eligible Indicator */
#define VLAN_VID_MASK		0x0fff /* VLAN Identifier */
#define VLAN_N_VID		4096

/* found in socket.c */
extern void vlan_ioctl_set(int (*hook)(struct net *, void __user *));

static inline bool is_vlan_dev(const struct net_device *dev)
{
        return dev->priv_flags & IFF_802_1Q_VLAN;
}

#define skb_vlan_tag_present(__skb)	((__skb)->vlan_present)
#define skb_vlan_tag_get(__skb)		((__skb)->vlan_tci)
#define skb_vlan_tag_get_id(__skb)	((__skb)->vlan_tci & VLAN_VID_MASK)
#define skb_vlan_tag_get_cfi(__skb)	(!!((__skb)->vlan_tci & VLAN_CFI_MASK))
#define skb_vlan_tag_get_prio(__skb)	(((__skb)->vlan_tci & VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT)

static inline int vlan_get_rx_ctag_filter_info(struct net_device *dev)
{
	ASSERT_RTNL();
	return notifier_to_errno(call_netdevice_notifiers(NETDEV_CVLAN_FILTER_PUSH_INFO, dev));
}

static inline void vlan_drop_rx_ctag_filter_info(struct net_device *dev)
{
	ASSERT_RTNL();
	call_netdevice_notifiers(NETDEV_CVLAN_FILTER_DROP_INFO, dev);
}

static inline int vlan_get_rx_stag_filter_info(struct net_device *dev)
{
	ASSERT_RTNL();
	return notifier_to_errno(call_netdevice_notifiers(NETDEV_SVLAN_FILTER_PUSH_INFO, dev));
}

static inline void vlan_drop_rx_stag_filter_info(struct net_device *dev)
{
	ASSERT_RTNL();
	call_netdevice_notifiers(NETDEV_SVLAN_FILTER_DROP_INFO, dev);
}

/**
 *	struct vlan_pcpu_stats - VLAN percpu rx/tx stats
 *	@rx_packets: number of received packets
 *	@rx_bytes: number of received bytes
 *	@rx_multicast: number of received multicast packets
 *	@tx_packets: number of transmitted packets
 *	@tx_bytes: number of transmitted bytes
 *	@syncp: synchronization point for 64bit counters
 *	@rx_errors: number of rx errors
 *	@tx_dropped: number of tx drops
 */
struct vlan_pcpu_stats {
	u64			rx_packets;
	u64			rx_bytes;
	u64			rx_multicast;
	u64			tx_packets;
	u64			tx_bytes;
	struct u64_stats_sync	syncp;
	u32			rx_errors;
	u32			tx_dropped;
};

#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)

extern struct net_device *__vlan_find_dev_deep_rcu(struct net_device *real_dev,
					       __be16 vlan_proto, u16 vlan_id);
extern int vlan_for_each(struct net_device *dev,
			 int (*action)(struct net_device *dev, int vid,
				       void *arg), void *arg);
extern struct net_device *vlan_dev_real_dev(const struct net_device *dev);
extern u16 vlan_dev_vlan_id(const struct net_device *dev);
extern __be16 vlan_dev_vlan_proto(const struct net_device *dev);

/**
 *	struct vlan_priority_tci_mapping - vlan egress priority mappings
 *	@priority: skb priority
 *	@vlan_qos: vlan priority: (skb->priority << 13) & 0xE000
 *	@next: pointer to next struct
 */
struct vlan_priority_tci_mapping {
	u32					priority;
	u16					vlan_qos;
	struct vlan_priority_tci_mapping	*next;
};

struct proc_dir_entry;
struct netpoll;

/**
 *	struct vlan_dev_priv - VLAN private device data
 *	@nr_ingress_mappings: number of ingress priority mappings
 *	@ingress_priority_map: ingress priority mappings
 *	@nr_egress_mappings: number of egress priority mappings
 *	@egress_priority_map: hash of egress priority mappings
 *	@vlan_proto: VLAN encapsulation protocol
 *	@vlan_id: VLAN identifier
 *	@flags: device flags
 *	@real_dev: underlying netdevice
 *	@real_dev_addr: address of underlying netdevice
 *	@dent: proc dir entry
 *	@vlan_pcpu_stats: ptr to percpu rx stats
 */
struct vlan_dev_priv {
	unsigned int				nr_ingress_mappings;
	u32					ingress_priority_map[8];
	unsigned int				nr_egress_mappings;
	struct vlan_priority_tci_mapping	*egress_priority_map[16];

	__be16					vlan_proto;
	u16					vlan_id;
	u16					flags;

	struct net_device			*real_dev;
	unsigned char				real_dev_addr[ETH_ALEN];

	struct proc_dir_entry			*dent;
	struct vlan_pcpu_stats __percpu		*vlan_pcpu_stats;
#ifdef CONFIG_NET_POLL_CONTROLLER
	struct netpoll				*netpoll;
#endif
};

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

static inline u16
vlan_dev_get_egress_qos_mask(struct net_device *dev, u32 skprio)
{
	struct vlan_priority_tci_mapping *mp;

	smp_rmb(); /* coupled with smp_wmb() in vlan_dev_set_egress_priority() */

	mp = vlan_dev_priv(dev)->egress_priority_map[(skprio & 0xF)];
	while (mp) {
		if (mp->priority == skprio) {
			return mp->vlan_qos; /* This should already be shifted
					      * to mask correctly with the
					      * VLAN's TCI */
		}
		mp = mp->next;
	}
	return 0;
}

extern bool vlan_do_receive(struct sk_buff **skb);

extern int vlan_vid_add(struct net_device *dev, __be16 proto, u16 vid);
extern void vlan_vid_del(struct net_device *dev, __be16 proto, u16 vid);

extern int vlan_vids_add_by_dev(struct net_device *dev,
				const struct net_device *by_dev);
extern void vlan_vids_del_by_dev(struct net_device *dev,
				 const struct net_device *by_dev);

extern bool vlan_uses_dev(const struct net_device *dev);

#else
static inline struct net_device *
__vlan_find_dev_deep_rcu(struct net_device *real_dev,
		     __be16 vlan_proto, u16 vlan_id)
{
	return NULL;
}

static inline int
vlan_for_each(struct net_device *dev,
	      int (*action)(struct net_device *dev, int vid, void *arg),
	      void *arg)
{
	return 0;
}

static inline struct net_device *vlan_dev_real_dev(const struct net_device *dev)
{
	BUG();
	return NULL;
}

static inline u16 vlan_dev_vlan_id(const struct net_device *dev)
{
	BUG();
	return 0;
}

static inline __be16 vlan_dev_vlan_proto(const struct net_device *dev)
{
	BUG();
	return 0;
}

static inline u16 vlan_dev_get_egress_qos_mask(struct net_device *dev,
					       u32 skprio)
{
	return 0;
}

static inline bool vlan_do_receive(struct sk_buff **skb)
{
	return false;
}

static inline int vlan_vid_add(struct net_device *dev, __be16 proto, u16 vid)
{
	return 0;
}

static inline void vlan_vid_del(struct net_device *dev, __be16 proto, u16 vid)
{
}

static inline int vlan_vids_add_by_dev(struct net_device *dev,
				       const struct net_device *by_dev)
{
	return 0;
}

static inline void vlan_vids_del_by_dev(struct net_device *dev,
					const struct net_device *by_dev)
{
}

static inline bool vlan_uses_dev(const struct net_device *dev)
{
	return false;
}
#endif

/**
 * eth_type_vlan - check for valid vlan ether type.
 * @ethertype: ether type to check
 *
 * Returns true if the ether type is a vlan ether type.
 */
static inline bool eth_type_vlan(__be16 ethertype)
{
	switch (ethertype) {
	case htons(ETH_P_8021Q):
	case htons(ETH_P_8021AD):
		return true;
	default:
		return false;
	}
}

static inline bool vlan_hw_offload_capable(netdev_features_t features,
					   __be16 proto)
{
	if (proto == htons(ETH_P_8021Q) && features & NETIF_F_HW_VLAN_CTAG_TX)
		return true;
	if (proto == htons(ETH_P_8021AD) && features & NETIF_F_HW_VLAN_STAG_TX)
		return true;
	return false;
}

/**
 * __vlan_insert_inner_tag - inner VLAN tag inserting
 * @skb: skbuff to tag
 * @vlan_proto: VLAN encapsulation protocol
 * @vlan_tci: VLAN TCI to insert
 * @mac_len: MAC header length including outer vlan headers
 *
 * Inserts the VLAN tag into @skb as part of the payload at offset mac_len
 * Returns error if skb_cow_head fails.
 *
 * Does not change skb->protocol so this function can be used during receive.
 */
static inline int __vlan_insert_inner_tag(struct sk_buff *skb,
					  __be16 vlan_proto, u16 vlan_tci,
					  unsigned int mac_len)
{
	struct vlan_ethhdr *veth;

	if (skb_cow_head(skb, VLAN_HLEN) < 0)
		return -ENOMEM;

	skb_push(skb, VLAN_HLEN);

	/* Move the mac header sans proto to the beginning of the new header. */
	if (likely(mac_len > ETH_TLEN))
		memmove(skb->data, skb->data + VLAN_HLEN, mac_len - ETH_TLEN);
	skb->mac_header -= VLAN_HLEN;

	veth = (struct vlan_ethhdr *)(skb->data + mac_len - ETH_HLEN);

	/* first, the ethernet type */
	if (likely(mac_len >= ETH_TLEN)) {
		/* h_vlan_encapsulated_proto should already be populated, and
		 * skb->data has space for h_vlan_proto
		 */
		veth->h_vlan_proto = vlan_proto;
	} else {
		/* h_vlan_encapsulated_proto should not be populated, and
		 * skb->data has no space for h_vlan_proto
		 */
		veth->h_vlan_encapsulated_proto = skb->protocol;
	}

	/* now, the TCI */
	veth->h_vlan_TCI = htons(vlan_tci);

	return 0;
}

/**
 * __vlan_insert_tag - regular VLAN tag inserting
 * @skb: skbuff to tag
 * @vlan_proto: VLAN encapsulation protocol
 * @vlan_tci: VLAN TCI to insert
 *
 * Inserts the VLAN tag into @skb as part of the payload
 * Returns error if skb_cow_head fails.
 *
 * Does not change skb->protocol so this function can be used during receive.
 */
static inline int __vlan_insert_tag(struct sk_buff *skb,
				    __be16 vlan_proto, u16 vlan_tci)
{
	return __vlan_insert_inner_tag(skb, vlan_proto, vlan_tci, ETH_HLEN);
}

/**
 * vlan_insert_inner_tag - inner VLAN tag inserting
 * @skb: skbuff to tag
 * @vlan_proto: VLAN encapsulation protocol
 * @vlan_tci: VLAN TCI to insert
 * @mac_len: MAC header length including outer vlan headers
 *
 * Inserts the VLAN tag into @skb as part of the payload at offset mac_len
 * Returns a VLAN tagged skb. If a new skb is created, @skb is freed.
 *
 * Following the skb_unshare() example, in case of error, the calling function
 * doesn't have to worry about freeing the original skb.
 *
 * Does not change skb->protocol so this function can be used during receive.
 */
static inline struct sk_buff *vlan_insert_inner_tag(struct sk_buff *skb,
						    __be16 vlan_proto,
						    u16 vlan_tci,
						    unsigned int mac_len)
{
	int err;

	err = __vlan_insert_inner_tag(skb, vlan_proto, vlan_tci, mac_len);
	if (err) {
		dev_kfree_skb_any(skb);
		return NULL;
	}
	return skb;
}

/**
 * vlan_insert_tag - regular VLAN tag inserting
 * @skb: skbuff to tag
 * @vlan_proto: VLAN encapsulation protocol
 * @vlan_tci: VLAN TCI to insert
 *
 * Inserts the VLAN tag into @skb as part of the payload
 * Returns a VLAN tagged skb. If a new skb is created, @skb is freed.
 *
 * Following the skb_unshare() example, in case of error, the calling function
 * doesn't have to worry about freeing the original skb.
 *
 * Does not change skb->protocol so this function can be used during receive.
 */
static inline struct sk_buff *vlan_insert_tag(struct sk_buff *skb,
					      __be16 vlan_proto, u16 vlan_tci)
{
	return vlan_insert_inner_tag(skb, vlan_proto, vlan_tci, ETH_HLEN);
}

/**
 * vlan_insert_tag_set_proto - regular VLAN tag inserting
 * @skb: skbuff to tag
 * @vlan_proto: VLAN encapsulation protocol
 * @vlan_tci: VLAN TCI to insert
 *
 * Inserts the VLAN tag into @skb as part of the payload
 * Returns a VLAN tagged skb. If a new skb is created, @skb is freed.
 *
 * Following the skb_unshare() example, in case of error, the calling function
 * doesn't have to worry about freeing the original skb.
 */
static inline struct sk_buff *vlan_insert_tag_set_proto(struct sk_buff *skb,
							__be16 vlan_proto,
							u16 vlan_tci)
{
	skb = vlan_insert_tag(skb, vlan_proto, vlan_tci);
	if (skb)
		skb->protocol = vlan_proto;
	return skb;
}

/**
 * __vlan_hwaccel_clear_tag - clear hardware accelerated VLAN info
 * @skb: skbuff to clear
 *
 * Clears the VLAN information from @skb
 */
static inline void __vlan_hwaccel_clear_tag(struct sk_buff *skb)
{
	skb->vlan_present = 0;
}

/**
 * __vlan_hwaccel_copy_tag - copy hardware accelerated VLAN info from another skb
 * @dst: skbuff to copy to
 * @src: skbuff to copy from
 *
 * Copies VLAN information from @src to @dst (for branchless code)
 */
static inline void __vlan_hwaccel_copy_tag(struct sk_buff *dst, const struct sk_buff *src)
{
	dst->vlan_present = src->vlan_present;
	dst->vlan_proto = src->vlan_proto;
	dst->vlan_tci = src->vlan_tci;
}

/*
 * __vlan_hwaccel_push_inside - pushes vlan tag to the payload
 * @skb: skbuff to tag
 *
 * Pushes the VLAN tag from @skb->vlan_tci inside to the payload.
 *
 * Following the skb_unshare() example, in case of error, the calling function
 * doesn't have to worry about freeing the original skb.
 */
static inline struct sk_buff *__vlan_hwaccel_push_inside(struct sk_buff *skb)
{
	skb = vlan_insert_tag_set_proto(skb, skb->vlan_proto,
					skb_vlan_tag_get(skb));
	if (likely(skb))
		__vlan_hwaccel_clear_tag(skb);
	return skb;
}

/**
 * __vlan_hwaccel_put_tag - hardware accelerated VLAN inserting
 * @skb: skbuff to tag
 * @vlan_proto: VLAN encapsulation protocol
 * @vlan_tci: VLAN TCI to insert
 *
 * Puts the VLAN TCI in @skb->vlan_tci and lets the device do the rest
 */
static inline void __vlan_hwaccel_put_tag(struct sk_buff *skb,
					  __be16 vlan_proto, u16 vlan_tci)
{
	skb->vlan_proto = vlan_proto;
	skb->vlan_tci = vlan_tci;
	skb->vlan_present = 1;
}

/**
 * __vlan_get_tag - get the VLAN ID that is part of the payload
 * @skb: skbuff to query
 * @vlan_tci: buffer to store value
 *
 * Returns error if the skb is not of VLAN type
 */
static inline int __vlan_get_tag(const struct sk_buff *skb, u16 *vlan_tci)
{
	struct vlan_ethhdr *veth = (struct vlan_ethhdr *)skb->data;

	if (!eth_type_vlan(veth->h_vlan_proto))
		return -EINVAL;

	*vlan_tci = ntohs(veth->h_vlan_TCI);
	return 0;
}

/**
 * __vlan_hwaccel_get_tag - get the VLAN ID that is in @skb->cb[]
 * @skb: skbuff to query
 * @vlan_tci: buffer to store value
 *
 * Returns error if @skb->vlan_tci is not set correctly
 */
static inline int __vlan_hwaccel_get_tag(const struct sk_buff *skb,
					 u16 *vlan_tci)
{
	if (skb_vlan_tag_present(skb)) {
		*vlan_tci = skb_vlan_tag_get(skb);
		return 0;
	} else {
		*vlan_tci = 0;
		return -EINVAL;
	}
}

/**
 * vlan_get_tag - get the VLAN ID from the skb
 * @skb: skbuff to query
 * @vlan_tci: buffer to store value
 *
 * Returns error if the skb is not VLAN tagged
 */
static inline int vlan_get_tag(const struct sk_buff *skb, u16 *vlan_tci)
{
	if (skb->dev->features & NETIF_F_HW_VLAN_CTAG_TX) {
		return __vlan_hwaccel_get_tag(skb, vlan_tci);
	} else {
		return __vlan_get_tag(skb, vlan_tci);
	}
}

/**
 * vlan_get_protocol - get protocol EtherType.
 * @skb: skbuff to query
 * @type: first vlan protocol
 * @depth: buffer to store length of eth and vlan tags in bytes
 *
 * Returns the EtherType of the packet, regardless of whether it is
 * vlan encapsulated (normal or hardware accelerated) or not.
 */
static inline __be16 __vlan_get_protocol(const struct sk_buff *skb, __be16 type,
					 int *depth)
{
	unsigned int vlan_depth = skb->mac_len, parse_depth = VLAN_MAX_DEPTH;

	/* if type is 802.1Q/AD then the header should already be
	 * present at mac_len - VLAN_HLEN (if mac_len > 0), or at
	 * ETH_HLEN otherwise
	 */
	if (eth_type_vlan(type)) {
		if (vlan_depth) {
			if (WARN_ON(vlan_depth < VLAN_HLEN))
				return 0;
			vlan_depth -= VLAN_HLEN;
		} else {
			vlan_depth = ETH_HLEN;
		}
		do {
			struct vlan_hdr vhdr, *vh;

			vh = skb_header_pointer(skb, vlan_depth, sizeof(vhdr), &vhdr);
			if (unlikely(!vh || !--parse_depth))
				return 0;

			type = vh->h_vlan_encapsulated_proto;
			vlan_depth += VLAN_HLEN;
		} while (eth_type_vlan(type));
	}

	if (depth)
		*depth = vlan_depth;

	return type;
}

/**
 * vlan_get_protocol - get protocol EtherType.
 * @skb: skbuff to query
 *
 * Returns the EtherType of the packet, regardless of whether it is
 * vlan encapsulated (normal or hardware accelerated) or not.
 */
static inline __be16 vlan_get_protocol(const struct sk_buff *skb)
{
	return __vlan_get_protocol(skb, skb->protocol, NULL);
}

/* A getter for the SKB protocol field which will handle VLAN tags consistently
 * whether VLAN acceleration is enabled or not.
 */
static inline __be16 skb_protocol(const struct sk_buff *skb, bool skip_vlan)
{
	if (!skip_vlan)
		/* VLAN acceleration strips the VLAN header from the skb and
		 * moves it to skb->vlan_proto
		 */
		return skb_vlan_tag_present(skb) ? skb->vlan_proto : skb->protocol;

	return vlan_get_protocol(skb);
}

static inline void vlan_set_encap_proto(struct sk_buff *skb,
					struct vlan_hdr *vhdr)
{
	__be16 proto;
	unsigned short *rawp;

	/*
	 * Was a VLAN packet, grab the encapsulated protocol, which the layer
	 * three protocols care about.
	 */

	proto = vhdr->h_vlan_encapsulated_proto;
	if (eth_proto_is_802_3(proto)) {
		skb->protocol = proto;
		return;
	}

	rawp = (unsigned short *)(vhdr + 1);
	if (*rawp == 0xFFFF)
		/*
		 * This is a magic hack to spot IPX packets. Older Novell
		 * breaks the protocol design and runs IPX over 802.3 without
		 * an 802.2 LLC layer. We look for FFFF which isn't a used
		 * 802.2 SSAP/DSAP. This won't work for fault tolerant netware
		 * but does for the rest.
		 */
		skb->protocol = htons(ETH_P_802_3);
	else
		/*
		 * Real 802.2 LLC
		 */
		skb->protocol = htons(ETH_P_802_2);
}

/**
 * skb_vlan_tagged - check if skb is vlan tagged.
 * @skb: skbuff to query
 *
 * Returns true if the skb is tagged, regardless of whether it is hardware
 * accelerated or not.
 */
static inline bool skb_vlan_tagged(const struct sk_buff *skb)
{
	if (!skb_vlan_tag_present(skb) &&
	    likely(!eth_type_vlan(skb->protocol)))
		return false;

	return true;
}

/**
 * skb_vlan_tagged_multi - check if skb is vlan tagged with multiple headers.
 * @skb: skbuff to query
 *
 * Returns true if the skb is tagged with multiple vlan headers, regardless
 * of whether it is hardware accelerated or not.
 */
static inline bool skb_vlan_tagged_multi(struct sk_buff *skb)
{
	__be16 protocol = skb->protocol;

	if (!skb_vlan_tag_present(skb)) {
		struct vlan_ethhdr *veh;

		if (likely(!eth_type_vlan(protocol)))
			return false;

		if (unlikely(!pskb_may_pull(skb, VLAN_ETH_HLEN)))
			return false;

		veh = (struct vlan_ethhdr *)skb->data;
		protocol = veh->h_vlan_encapsulated_proto;
	}

	if (!eth_type_vlan(protocol))
		return false;

	return true;
}

/**
 * vlan_features_check - drop unsafe features for skb with multiple tags.
 * @skb: skbuff to query
 * @features: features to be checked
 *
 * Returns features without unsafe ones if the skb has multiple tags.
 */
static inline netdev_features_t vlan_features_check(struct sk_buff *skb,
						    netdev_features_t features)
{
	if (skb_vlan_tagged_multi(skb)) {
		/* In the case of multi-tagged packets, use a direct mask
		 * instead of using netdev_interesect_features(), to make
		 * sure that only devices supporting NETIF_F_HW_CSUM will
		 * have checksum offloading support.
		 */
		features &= NETIF_F_SG | NETIF_F_HIGHDMA | NETIF_F_HW_CSUM |
			    NETIF_F_FRAGLIST | NETIF_F_HW_VLAN_CTAG_TX |
			    NETIF_F_HW_VLAN_STAG_TX;
	}

	return features;
}

/**
 * compare_vlan_header - Compare two vlan headers
 * @h1: Pointer to vlan header
 * @h2: Pointer to vlan header
 *
 * Compare two vlan headers, returns 0 if equal.
 *
 * Please note that alignment of h1 & h2 are only guaranteed to be 16 bits.
 */
static inline unsigned long compare_vlan_header(const struct vlan_hdr *h1,
						const struct vlan_hdr *h2)
{
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
	return *(u32 *)h1 ^ *(u32 *)h2;
#else
	return ((__force u32)h1->h_vlan_TCI ^ (__force u32)h2->h_vlan_TCI) |
	       ((__force u32)h1->h_vlan_encapsulated_proto ^
		(__force u32)h2->h_vlan_encapsulated_proto);
#endif
}
#endif /* !(_LINUX_IF_VLAN_H_) */