1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * VLAN An implementation of 802.1Q VLAN tagging.
4 *
5 * Authors: Ben Greear <greearb@candelatech.com>
6 */
7#ifndef _LINUX_IF_VLAN_H_
8#define _LINUX_IF_VLAN_H_
9
10#include <linux/netdevice.h>
11#include <linux/etherdevice.h>
12#include <linux/rtnetlink.h>
13#include <linux/bug.h>
14#include <uapi/linux/if_vlan.h>
15
16#define VLAN_HLEN 4 /* The additional bytes required by VLAN
17 * (in addition to the Ethernet header)
18 */
19#define VLAN_ETH_HLEN 18 /* Total octets in header. */
20#define VLAN_ETH_ZLEN 64 /* Min. octets in frame sans FCS */
21
22/*
23 * According to 802.3ac, the packet can be 4 bytes longer. --Klika Jan
24 */
25#define VLAN_ETH_DATA_LEN 1500 /* Max. octets in payload */
26#define VLAN_ETH_FRAME_LEN 1518 /* Max. octets in frame sans FCS */
27
28#define VLAN_MAX_DEPTH 8 /* Max. number of nested VLAN tags parsed */
29
30/*
31 * struct vlan_hdr - vlan header
32 * @h_vlan_TCI: priority and VLAN ID
33 * @h_vlan_encapsulated_proto: packet type ID or len
34 */
35struct vlan_hdr {
36 __be16 h_vlan_TCI;
37 __be16 h_vlan_encapsulated_proto;
38};
39
40/**
41 * struct vlan_ethhdr - vlan ethernet header (ethhdr + vlan_hdr)
42 * @h_dest: destination ethernet address
43 * @h_source: source ethernet address
44 * @h_vlan_proto: ethernet protocol
45 * @h_vlan_TCI: priority and VLAN ID
46 * @h_vlan_encapsulated_proto: packet type ID or len
47 */
48struct vlan_ethhdr {
49 struct_group(addrs,
50 unsigned char h_dest[ETH_ALEN];
51 unsigned char h_source[ETH_ALEN];
52 );
53 __be16 h_vlan_proto;
54 __be16 h_vlan_TCI;
55 __be16 h_vlan_encapsulated_proto;
56};
57
58#include <linux/skbuff.h>
59
60static inline struct vlan_ethhdr *vlan_eth_hdr(const struct sk_buff *skb)
61{
62 return (struct vlan_ethhdr *)skb_mac_header(skb);
63}
64
65#define VLAN_PRIO_MASK 0xe000 /* Priority Code Point */
66#define VLAN_PRIO_SHIFT 13
67#define VLAN_CFI_MASK 0x1000 /* Canonical Format Indicator / Drop Eligible Indicator */
68#define VLAN_VID_MASK 0x0fff /* VLAN Identifier */
69#define VLAN_N_VID 4096
70
71/* found in socket.c */
72extern void vlan_ioctl_set(int (*hook)(struct net *, void __user *));
73
74static inline bool is_vlan_dev(const struct net_device *dev)
75{
76 return dev->priv_flags & IFF_802_1Q_VLAN;
77}
78
79#define skb_vlan_tag_present(__skb) ((__skb)->vlan_present)
80#define skb_vlan_tag_get(__skb) ((__skb)->vlan_tci)
81#define skb_vlan_tag_get_id(__skb) ((__skb)->vlan_tci & VLAN_VID_MASK)
82#define skb_vlan_tag_get_cfi(__skb) (!!((__skb)->vlan_tci & VLAN_CFI_MASK))
83#define skb_vlan_tag_get_prio(__skb) (((__skb)->vlan_tci & VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT)
84
85static inline int vlan_get_rx_ctag_filter_info(struct net_device *dev)
86{
87 ASSERT_RTNL();
88 return notifier_to_errno(call_netdevice_notifiers(NETDEV_CVLAN_FILTER_PUSH_INFO, dev));
89}
90
91static inline void vlan_drop_rx_ctag_filter_info(struct net_device *dev)
92{
93 ASSERT_RTNL();
94 call_netdevice_notifiers(NETDEV_CVLAN_FILTER_DROP_INFO, dev);
95}
96
97static inline int vlan_get_rx_stag_filter_info(struct net_device *dev)
98{
99 ASSERT_RTNL();
100 return notifier_to_errno(call_netdevice_notifiers(NETDEV_SVLAN_FILTER_PUSH_INFO, dev));
101}
102
103static inline void vlan_drop_rx_stag_filter_info(struct net_device *dev)
104{
105 ASSERT_RTNL();
106 call_netdevice_notifiers(NETDEV_SVLAN_FILTER_DROP_INFO, dev);
107}
108
109/**
110 * struct vlan_pcpu_stats - VLAN percpu rx/tx stats
111 * @rx_packets: number of received packets
112 * @rx_bytes: number of received bytes
113 * @rx_multicast: number of received multicast packets
114 * @tx_packets: number of transmitted packets
115 * @tx_bytes: number of transmitted bytes
116 * @syncp: synchronization point for 64bit counters
117 * @rx_errors: number of rx errors
118 * @tx_dropped: number of tx drops
119 */
120struct vlan_pcpu_stats {
121 u64_stats_t rx_packets;
122 u64_stats_t rx_bytes;
123 u64_stats_t rx_multicast;
124 u64_stats_t tx_packets;
125 u64_stats_t tx_bytes;
126 struct u64_stats_sync syncp;
127 u32 rx_errors;
128 u32 tx_dropped;
129};
130
131#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
132
133extern struct net_device *__vlan_find_dev_deep_rcu(struct net_device *real_dev,
134 __be16 vlan_proto, u16 vlan_id);
135extern int vlan_for_each(struct net_device *dev,
136 int (*action)(struct net_device *dev, int vid,
137 void *arg), void *arg);
138extern struct net_device *vlan_dev_real_dev(const struct net_device *dev);
139extern u16 vlan_dev_vlan_id(const struct net_device *dev);
140extern __be16 vlan_dev_vlan_proto(const struct net_device *dev);
141
142/**
143 * struct vlan_priority_tci_mapping - vlan egress priority mappings
144 * @priority: skb priority
145 * @vlan_qos: vlan priority: (skb->priority << 13) & 0xE000
146 * @next: pointer to next struct
147 */
148struct vlan_priority_tci_mapping {
149 u32 priority;
150 u16 vlan_qos;
151 struct vlan_priority_tci_mapping *next;
152};
153
154struct proc_dir_entry;
155struct netpoll;
156
157/**
158 * struct vlan_dev_priv - VLAN private device data
159 * @nr_ingress_mappings: number of ingress priority mappings
160 * @ingress_priority_map: ingress priority mappings
161 * @nr_egress_mappings: number of egress priority mappings
162 * @egress_priority_map: hash of egress priority mappings
163 * @vlan_proto: VLAN encapsulation protocol
164 * @vlan_id: VLAN identifier
165 * @flags: device flags
166 * @real_dev: underlying netdevice
167 * @dev_tracker: refcount tracker for @real_dev reference
168 * @real_dev_addr: address of underlying netdevice
169 * @dent: proc dir entry
170 * @vlan_pcpu_stats: ptr to percpu rx stats
171 */
172struct vlan_dev_priv {
173 unsigned int nr_ingress_mappings;
174 u32 ingress_priority_map[8];
175 unsigned int nr_egress_mappings;
176 struct vlan_priority_tci_mapping *egress_priority_map[16];
177
178 __be16 vlan_proto;
179 u16 vlan_id;
180 u16 flags;
181
182 struct net_device *real_dev;
183 netdevice_tracker dev_tracker;
184
185 unsigned char real_dev_addr[ETH_ALEN];
186
187 struct proc_dir_entry *dent;
188 struct vlan_pcpu_stats __percpu *vlan_pcpu_stats;
189#ifdef CONFIG_NET_POLL_CONTROLLER
190 struct netpoll *netpoll;
191#endif
192};
193
194static inline struct vlan_dev_priv *vlan_dev_priv(const struct net_device *dev)
195{
196 return netdev_priv(dev);
197}
198
199static inline u16
200vlan_dev_get_egress_qos_mask(struct net_device *dev, u32 skprio)
201{
202 struct vlan_priority_tci_mapping *mp;
203
204 smp_rmb(); /* coupled with smp_wmb() in vlan_dev_set_egress_priority() */
205
206 mp = vlan_dev_priv(dev)->egress_priority_map[(skprio & 0xF)];
207 while (mp) {
208 if (mp->priority == skprio) {
209 return mp->vlan_qos; /* This should already be shifted
210 * to mask correctly with the
211 * VLAN's TCI */
212 }
213 mp = mp->next;
214 }
215 return 0;
216}
217
218extern bool vlan_do_receive(struct sk_buff **skb);
219
220extern int vlan_vid_add(struct net_device *dev, __be16 proto, u16 vid);
221extern void vlan_vid_del(struct net_device *dev, __be16 proto, u16 vid);
222
223extern int vlan_vids_add_by_dev(struct net_device *dev,
224 const struct net_device *by_dev);
225extern void vlan_vids_del_by_dev(struct net_device *dev,
226 const struct net_device *by_dev);
227
228extern bool vlan_uses_dev(const struct net_device *dev);
229
230#else
231static inline struct net_device *
232__vlan_find_dev_deep_rcu(struct net_device *real_dev,
233 __be16 vlan_proto, u16 vlan_id)
234{
235 return NULL;
236}
237
238static inline int
239vlan_for_each(struct net_device *dev,
240 int (*action)(struct net_device *dev, int vid, void *arg),
241 void *arg)
242{
243 return 0;
244}
245
246static inline struct net_device *vlan_dev_real_dev(const struct net_device *dev)
247{
248 BUG();
249 return NULL;
250}
251
252static inline u16 vlan_dev_vlan_id(const struct net_device *dev)
253{
254 BUG();
255 return 0;
256}
257
258static inline __be16 vlan_dev_vlan_proto(const struct net_device *dev)
259{
260 BUG();
261 return 0;
262}
263
264static inline u16 vlan_dev_get_egress_qos_mask(struct net_device *dev,
265 u32 skprio)
266{
267 return 0;
268}
269
270static inline bool vlan_do_receive(struct sk_buff **skb)
271{
272 return false;
273}
274
275static inline int vlan_vid_add(struct net_device *dev, __be16 proto, u16 vid)
276{
277 return 0;
278}
279
280static inline void vlan_vid_del(struct net_device *dev, __be16 proto, u16 vid)
281{
282}
283
284static inline int vlan_vids_add_by_dev(struct net_device *dev,
285 const struct net_device *by_dev)
286{
287 return 0;
288}
289
290static inline void vlan_vids_del_by_dev(struct net_device *dev,
291 const struct net_device *by_dev)
292{
293}
294
295static inline bool vlan_uses_dev(const struct net_device *dev)
296{
297 return false;
298}
299#endif
300
301/**
302 * eth_type_vlan - check for valid vlan ether type.
303 * @ethertype: ether type to check
304 *
305 * Returns true if the ether type is a vlan ether type.
306 */
307static inline bool eth_type_vlan(__be16 ethertype)
308{
309 switch (ethertype) {
310 case htons(ETH_P_8021Q):
311 case htons(ETH_P_8021AD):
312 return true;
313 default:
314 return false;
315 }
316}
317
318static inline bool vlan_hw_offload_capable(netdev_features_t features,
319 __be16 proto)
320{
321 if (proto == htons(ETH_P_8021Q) && features & NETIF_F_HW_VLAN_CTAG_TX)
322 return true;
323 if (proto == htons(ETH_P_8021AD) && features & NETIF_F_HW_VLAN_STAG_TX)
324 return true;
325 return false;
326}
327
328/**
329 * __vlan_insert_inner_tag - inner VLAN tag inserting
330 * @skb: skbuff to tag
331 * @vlan_proto: VLAN encapsulation protocol
332 * @vlan_tci: VLAN TCI to insert
333 * @mac_len: MAC header length including outer vlan headers
334 *
335 * Inserts the VLAN tag into @skb as part of the payload at offset mac_len
336 * Returns error if skb_cow_head fails.
337 *
338 * Does not change skb->protocol so this function can be used during receive.
339 */
340static inline int __vlan_insert_inner_tag(struct sk_buff *skb,
341 __be16 vlan_proto, u16 vlan_tci,
342 unsigned int mac_len)
343{
344 struct vlan_ethhdr *veth;
345
346 if (skb_cow_head(skb, VLAN_HLEN) < 0)
347 return -ENOMEM;
348
349 skb_push(skb, VLAN_HLEN);
350
351 /* Move the mac header sans proto to the beginning of the new header. */
352 if (likely(mac_len > ETH_TLEN))
353 memmove(skb->data, skb->data + VLAN_HLEN, mac_len - ETH_TLEN);
354 skb->mac_header -= VLAN_HLEN;
355
356 veth = (struct vlan_ethhdr *)(skb->data + mac_len - ETH_HLEN);
357
358 /* first, the ethernet type */
359 if (likely(mac_len >= ETH_TLEN)) {
360 /* h_vlan_encapsulated_proto should already be populated, and
361 * skb->data has space for h_vlan_proto
362 */
363 veth->h_vlan_proto = vlan_proto;
364 } else {
365 /* h_vlan_encapsulated_proto should not be populated, and
366 * skb->data has no space for h_vlan_proto
367 */
368 veth->h_vlan_encapsulated_proto = skb->protocol;
369 }
370
371 /* now, the TCI */
372 veth->h_vlan_TCI = htons(vlan_tci);
373
374 return 0;
375}
376
377/**
378 * __vlan_insert_tag - regular VLAN tag inserting
379 * @skb: skbuff to tag
380 * @vlan_proto: VLAN encapsulation protocol
381 * @vlan_tci: VLAN TCI to insert
382 *
383 * Inserts the VLAN tag into @skb as part of the payload
384 * Returns error if skb_cow_head fails.
385 *
386 * Does not change skb->protocol so this function can be used during receive.
387 */
388static inline int __vlan_insert_tag(struct sk_buff *skb,
389 __be16 vlan_proto, u16 vlan_tci)
390{
391 return __vlan_insert_inner_tag(skb, vlan_proto, vlan_tci, ETH_HLEN);
392}
393
394/**
395 * vlan_insert_inner_tag - inner VLAN tag inserting
396 * @skb: skbuff to tag
397 * @vlan_proto: VLAN encapsulation protocol
398 * @vlan_tci: VLAN TCI to insert
399 * @mac_len: MAC header length including outer vlan headers
400 *
401 * Inserts the VLAN tag into @skb as part of the payload at offset mac_len
402 * Returns a VLAN tagged skb. If a new skb is created, @skb is freed.
403 *
404 * Following the skb_unshare() example, in case of error, the calling function
405 * doesn't have to worry about freeing the original skb.
406 *
407 * Does not change skb->protocol so this function can be used during receive.
408 */
409static inline struct sk_buff *vlan_insert_inner_tag(struct sk_buff *skb,
410 __be16 vlan_proto,
411 u16 vlan_tci,
412 unsigned int mac_len)
413{
414 int err;
415
416 err = __vlan_insert_inner_tag(skb, vlan_proto, vlan_tci, mac_len);
417 if (err) {
418 dev_kfree_skb_any(skb);
419 return NULL;
420 }
421 return skb;
422}
423
424/**
425 * vlan_insert_tag - regular VLAN tag inserting
426 * @skb: skbuff to tag
427 * @vlan_proto: VLAN encapsulation protocol
428 * @vlan_tci: VLAN TCI to insert
429 *
430 * Inserts the VLAN tag into @skb as part of the payload
431 * Returns a VLAN tagged skb. If a new skb is created, @skb is freed.
432 *
433 * Following the skb_unshare() example, in case of error, the calling function
434 * doesn't have to worry about freeing the original skb.
435 *
436 * Does not change skb->protocol so this function can be used during receive.
437 */
438static inline struct sk_buff *vlan_insert_tag(struct sk_buff *skb,
439 __be16 vlan_proto, u16 vlan_tci)
440{
441 return vlan_insert_inner_tag(skb, vlan_proto, vlan_tci, ETH_HLEN);
442}
443
444/**
445 * vlan_insert_tag_set_proto - regular VLAN tag inserting
446 * @skb: skbuff to tag
447 * @vlan_proto: VLAN encapsulation protocol
448 * @vlan_tci: VLAN TCI to insert
449 *
450 * Inserts the VLAN tag into @skb as part of the payload
451 * Returns a VLAN tagged skb. If a new skb is created, @skb is freed.
452 *
453 * Following the skb_unshare() example, in case of error, the calling function
454 * doesn't have to worry about freeing the original skb.
455 */
456static inline struct sk_buff *vlan_insert_tag_set_proto(struct sk_buff *skb,
457 __be16 vlan_proto,
458 u16 vlan_tci)
459{
460 skb = vlan_insert_tag(skb, vlan_proto, vlan_tci);
461 if (skb)
462 skb->protocol = vlan_proto;
463 return skb;
464}
465
466/**
467 * __vlan_hwaccel_clear_tag - clear hardware accelerated VLAN info
468 * @skb: skbuff to clear
469 *
470 * Clears the VLAN information from @skb
471 */
472static inline void __vlan_hwaccel_clear_tag(struct sk_buff *skb)
473{
474 skb->vlan_present = 0;
475}
476
477/**
478 * __vlan_hwaccel_copy_tag - copy hardware accelerated VLAN info from another skb
479 * @dst: skbuff to copy to
480 * @src: skbuff to copy from
481 *
482 * Copies VLAN information from @src to @dst (for branchless code)
483 */
484static inline void __vlan_hwaccel_copy_tag(struct sk_buff *dst, const struct sk_buff *src)
485{
486 dst->vlan_present = src->vlan_present;
487 dst->vlan_proto = src->vlan_proto;
488 dst->vlan_tci = src->vlan_tci;
489}
490
491/*
492 * __vlan_hwaccel_push_inside - pushes vlan tag to the payload
493 * @skb: skbuff to tag
494 *
495 * Pushes the VLAN tag from @skb->vlan_tci inside to the payload.
496 *
497 * Following the skb_unshare() example, in case of error, the calling function
498 * doesn't have to worry about freeing the original skb.
499 */
500static inline struct sk_buff *__vlan_hwaccel_push_inside(struct sk_buff *skb)
501{
502 skb = vlan_insert_tag_set_proto(skb, skb->vlan_proto,
503 skb_vlan_tag_get(skb));
504 if (likely(skb))
505 __vlan_hwaccel_clear_tag(skb);
506 return skb;
507}
508
509/**
510 * __vlan_hwaccel_put_tag - hardware accelerated VLAN inserting
511 * @skb: skbuff to tag
512 * @vlan_proto: VLAN encapsulation protocol
513 * @vlan_tci: VLAN TCI to insert
514 *
515 * Puts the VLAN TCI in @skb->vlan_tci and lets the device do the rest
516 */
517static inline void __vlan_hwaccel_put_tag(struct sk_buff *skb,
518 __be16 vlan_proto, u16 vlan_tci)
519{
520 skb->vlan_proto = vlan_proto;
521 skb->vlan_tci = vlan_tci;
522 skb->vlan_present = 1;
523}
524
525/**
526 * __vlan_get_tag - get the VLAN ID that is part of the payload
527 * @skb: skbuff to query
528 * @vlan_tci: buffer to store value
529 *
530 * Returns error if the skb is not of VLAN type
531 */
532static inline int __vlan_get_tag(const struct sk_buff *skb, u16 *vlan_tci)
533{
534 struct vlan_ethhdr *veth = (struct vlan_ethhdr *)skb->data;
535
536 if (!eth_type_vlan(veth->h_vlan_proto))
537 return -EINVAL;
538
539 *vlan_tci = ntohs(veth->h_vlan_TCI);
540 return 0;
541}
542
543/**
544 * __vlan_hwaccel_get_tag - get the VLAN ID that is in @skb->cb[]
545 * @skb: skbuff to query
546 * @vlan_tci: buffer to store value
547 *
548 * Returns error if @skb->vlan_tci is not set correctly
549 */
550static inline int __vlan_hwaccel_get_tag(const struct sk_buff *skb,
551 u16 *vlan_tci)
552{
553 if (skb_vlan_tag_present(skb)) {
554 *vlan_tci = skb_vlan_tag_get(skb);
555 return 0;
556 } else {
557 *vlan_tci = 0;
558 return -EINVAL;
559 }
560}
561
562/**
563 * vlan_get_tag - get the VLAN ID from the skb
564 * @skb: skbuff to query
565 * @vlan_tci: buffer to store value
566 *
567 * Returns error if the skb is not VLAN tagged
568 */
569static inline int vlan_get_tag(const struct sk_buff *skb, u16 *vlan_tci)
570{
571 if (skb->dev->features & NETIF_F_HW_VLAN_CTAG_TX) {
572 return __vlan_hwaccel_get_tag(skb, vlan_tci);
573 } else {
574 return __vlan_get_tag(skb, vlan_tci);
575 }
576}
577
578/**
579 * vlan_get_protocol - get protocol EtherType.
580 * @skb: skbuff to query
581 * @type: first vlan protocol
582 * @depth: buffer to store length of eth and vlan tags in bytes
583 *
584 * Returns the EtherType of the packet, regardless of whether it is
585 * vlan encapsulated (normal or hardware accelerated) or not.
586 */
587static inline __be16 __vlan_get_protocol(const struct sk_buff *skb, __be16 type,
588 int *depth)
589{
590 unsigned int vlan_depth = skb->mac_len, parse_depth = VLAN_MAX_DEPTH;
591
592 /* if type is 802.1Q/AD then the header should already be
593 * present at mac_len - VLAN_HLEN (if mac_len > 0), or at
594 * ETH_HLEN otherwise
595 */
596 if (eth_type_vlan(type)) {
597 if (vlan_depth) {
598 if (WARN_ON(vlan_depth < VLAN_HLEN))
599 return 0;
600 vlan_depth -= VLAN_HLEN;
601 } else {
602 vlan_depth = ETH_HLEN;
603 }
604 do {
605 struct vlan_hdr vhdr, *vh;
606
607 vh = skb_header_pointer(skb, vlan_depth, sizeof(vhdr), &vhdr);
608 if (unlikely(!vh || !--parse_depth))
609 return 0;
610
611 type = vh->h_vlan_encapsulated_proto;
612 vlan_depth += VLAN_HLEN;
613 } while (eth_type_vlan(type));
614 }
615
616 if (depth)
617 *depth = vlan_depth;
618
619 return type;
620}
621
622/**
623 * vlan_get_protocol - get protocol EtherType.
624 * @skb: skbuff to query
625 *
626 * Returns the EtherType of the packet, regardless of whether it is
627 * vlan encapsulated (normal or hardware accelerated) or not.
628 */
629static inline __be16 vlan_get_protocol(const struct sk_buff *skb)
630{
631 return __vlan_get_protocol(skb, skb->protocol, NULL);
632}
633
634/* A getter for the SKB protocol field which will handle VLAN tags consistently
635 * whether VLAN acceleration is enabled or not.
636 */
637static inline __be16 skb_protocol(const struct sk_buff *skb, bool skip_vlan)
638{
639 if (!skip_vlan)
640 /* VLAN acceleration strips the VLAN header from the skb and
641 * moves it to skb->vlan_proto
642 */
643 return skb_vlan_tag_present(skb) ? skb->vlan_proto : skb->protocol;
644
645 return vlan_get_protocol(skb);
646}
647
648static inline void vlan_set_encap_proto(struct sk_buff *skb,
649 struct vlan_hdr *vhdr)
650{
651 __be16 proto;
652 unsigned short *rawp;
653
654 /*
655 * Was a VLAN packet, grab the encapsulated protocol, which the layer
656 * three protocols care about.
657 */
658
659 proto = vhdr->h_vlan_encapsulated_proto;
660 if (eth_proto_is_802_3(proto)) {
661 skb->protocol = proto;
662 return;
663 }
664
665 rawp = (unsigned short *)(vhdr + 1);
666 if (*rawp == 0xFFFF)
667 /*
668 * This is a magic hack to spot IPX packets. Older Novell
669 * breaks the protocol design and runs IPX over 802.3 without
670 * an 802.2 LLC layer. We look for FFFF which isn't a used
671 * 802.2 SSAP/DSAP. This won't work for fault tolerant netware
672 * but does for the rest.
673 */
674 skb->protocol = htons(ETH_P_802_3);
675 else
676 /*
677 * Real 802.2 LLC
678 */
679 skb->protocol = htons(ETH_P_802_2);
680}
681
682/**
683 * skb_vlan_tagged - check if skb is vlan tagged.
684 * @skb: skbuff to query
685 *
686 * Returns true if the skb is tagged, regardless of whether it is hardware
687 * accelerated or not.
688 */
689static inline bool skb_vlan_tagged(const struct sk_buff *skb)
690{
691 if (!skb_vlan_tag_present(skb) &&
692 likely(!eth_type_vlan(skb->protocol)))
693 return false;
694
695 return true;
696}
697
698/**
699 * skb_vlan_tagged_multi - check if skb is vlan tagged with multiple headers.
700 * @skb: skbuff to query
701 *
702 * Returns true if the skb is tagged with multiple vlan headers, regardless
703 * of whether it is hardware accelerated or not.
704 */
705static inline bool skb_vlan_tagged_multi(struct sk_buff *skb)
706{
707 __be16 protocol = skb->protocol;
708
709 if (!skb_vlan_tag_present(skb)) {
710 struct vlan_ethhdr *veh;
711
712 if (likely(!eth_type_vlan(protocol)))
713 return false;
714
715 if (unlikely(!pskb_may_pull(skb, VLAN_ETH_HLEN)))
716 return false;
717
718 veh = (struct vlan_ethhdr *)skb->data;
719 protocol = veh->h_vlan_encapsulated_proto;
720 }
721
722 if (!eth_type_vlan(protocol))
723 return false;
724
725 return true;
726}
727
728/**
729 * vlan_features_check - drop unsafe features for skb with multiple tags.
730 * @skb: skbuff to query
731 * @features: features to be checked
732 *
733 * Returns features without unsafe ones if the skb has multiple tags.
734 */
735static inline netdev_features_t vlan_features_check(struct sk_buff *skb,
736 netdev_features_t features)
737{
738 if (skb_vlan_tagged_multi(skb)) {
739 /* In the case of multi-tagged packets, use a direct mask
740 * instead of using netdev_interesect_features(), to make
741 * sure that only devices supporting NETIF_F_HW_CSUM will
742 * have checksum offloading support.
743 */
744 features &= NETIF_F_SG | NETIF_F_HIGHDMA | NETIF_F_HW_CSUM |
745 NETIF_F_FRAGLIST | NETIF_F_HW_VLAN_CTAG_TX |
746 NETIF_F_HW_VLAN_STAG_TX;
747 }
748
749 return features;
750}
751
752/**
753 * compare_vlan_header - Compare two vlan headers
754 * @h1: Pointer to vlan header
755 * @h2: Pointer to vlan header
756 *
757 * Compare two vlan headers, returns 0 if equal.
758 *
759 * Please note that alignment of h1 & h2 are only guaranteed to be 16 bits.
760 */
761static inline unsigned long compare_vlan_header(const struct vlan_hdr *h1,
762 const struct vlan_hdr *h2)
763{
764#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
765 return *(u32 *)h1 ^ *(u32 *)h2;
766#else
767 return ((__force u32)h1->h_vlan_TCI ^ (__force u32)h2->h_vlan_TCI) |
768 ((__force u32)h1->h_vlan_encapsulated_proto ^
769 (__force u32)h2->h_vlan_encapsulated_proto);
770#endif
771}
772#endif /* !(_LINUX_IF_VLAN_H_) */
773

source code of linux/include/linux/if_vlan.h