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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/* Prefer this version in TX path, instead of
66 * skb_reset_mac_header() + vlan_eth_hdr()
67 */
68static inline struct vlan_ethhdr *skb_vlan_eth_hdr(const struct sk_buff *skb)
69{
70 return (struct vlan_ethhdr *)skb->data;
71}
72
73#define VLAN_PRIO_MASK 0xe000 /* Priority Code Point */
74#define VLAN_PRIO_SHIFT 13
75#define VLAN_CFI_MASK 0x1000 /* Canonical Format Indicator / Drop Eligible Indicator */
76#define VLAN_VID_MASK 0x0fff /* VLAN Identifier */
77#define VLAN_N_VID 4096
78
79/* found in socket.c */
80extern void vlan_ioctl_set(int (*hook)(struct net *, void __user *));
81
82#define skb_vlan_tag_present(__skb) (!!(__skb)->vlan_all)
83#define skb_vlan_tag_get(__skb) ((__skb)->vlan_tci)
84#define skb_vlan_tag_get_id(__skb) ((__skb)->vlan_tci & VLAN_VID_MASK)
85#define skb_vlan_tag_get_cfi(__skb) (!!((__skb)->vlan_tci & VLAN_CFI_MASK))
86#define skb_vlan_tag_get_prio(__skb) (((__skb)->vlan_tci & VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT)
87
88static inline int vlan_get_rx_ctag_filter_info(struct net_device *dev)
89{
90 ASSERT_RTNL();
91 return notifier_to_errno(ret: call_netdevice_notifiers(val: NETDEV_CVLAN_FILTER_PUSH_INFO, dev));
92}
93
94static inline void vlan_drop_rx_ctag_filter_info(struct net_device *dev)
95{
96 ASSERT_RTNL();
97 call_netdevice_notifiers(val: NETDEV_CVLAN_FILTER_DROP_INFO, dev);
98}
99
100static inline int vlan_get_rx_stag_filter_info(struct net_device *dev)
101{
102 ASSERT_RTNL();
103 return notifier_to_errno(ret: call_netdevice_notifiers(val: NETDEV_SVLAN_FILTER_PUSH_INFO, dev));
104}
105
106static inline void vlan_drop_rx_stag_filter_info(struct net_device *dev)
107{
108 ASSERT_RTNL();
109 call_netdevice_notifiers(val: NETDEV_SVLAN_FILTER_DROP_INFO, dev);
110}
111
112/**
113 * struct vlan_pcpu_stats - VLAN percpu rx/tx stats
114 * @rx_packets: number of received packets
115 * @rx_bytes: number of received bytes
116 * @rx_multicast: number of received multicast packets
117 * @tx_packets: number of transmitted packets
118 * @tx_bytes: number of transmitted bytes
119 * @syncp: synchronization point for 64bit counters
120 * @rx_errors: number of rx errors
121 * @tx_dropped: number of tx drops
122 */
123struct vlan_pcpu_stats {
124 u64_stats_t rx_packets;
125 u64_stats_t rx_bytes;
126 u64_stats_t rx_multicast;
127 u64_stats_t tx_packets;
128 u64_stats_t tx_bytes;
129 struct u64_stats_sync syncp;
130 u32 rx_errors;
131 u32 tx_dropped;
132};
133
134#if IS_ENABLED(CONFIG_VLAN_8021Q)
135
136extern struct net_device *__vlan_find_dev_deep_rcu(struct net_device *real_dev,
137 __be16 vlan_proto, u16 vlan_id);
138extern int vlan_for_each(struct net_device *dev,
139 int (*action)(struct net_device *dev, int vid,
140 void *arg), void *arg);
141extern struct net_device *vlan_dev_real_dev(const struct net_device *dev);
142extern u16 vlan_dev_vlan_id(const struct net_device *dev);
143extern __be16 vlan_dev_vlan_proto(const struct net_device *dev);
144
145/**
146 * struct vlan_priority_tci_mapping - vlan egress priority mappings
147 * @priority: skb priority
148 * @vlan_qos: vlan priority: (skb->priority << 13) & 0xE000
149 * @next: pointer to next struct
150 */
151struct vlan_priority_tci_mapping {
152 u32 priority;
153 u16 vlan_qos;
154 struct vlan_priority_tci_mapping *next;
155};
156
157struct proc_dir_entry;
158struct netpoll;
159
160/**
161 * struct vlan_dev_priv - VLAN private device data
162 * @nr_ingress_mappings: number of ingress priority mappings
163 * @ingress_priority_map: ingress priority mappings
164 * @nr_egress_mappings: number of egress priority mappings
165 * @egress_priority_map: hash of egress priority mappings
166 * @vlan_proto: VLAN encapsulation protocol
167 * @vlan_id: VLAN identifier
168 * @flags: device flags
169 * @real_dev: underlying netdevice
170 * @dev_tracker: refcount tracker for @real_dev reference
171 * @real_dev_addr: address of underlying netdevice
172 * @dent: proc dir entry
173 * @vlan_pcpu_stats: ptr to percpu rx stats
174 * @netpoll: netpoll instance "propagated" down to @real_dev
175 */
176struct vlan_dev_priv {
177 unsigned int nr_ingress_mappings;
178 u32 ingress_priority_map[8];
179 unsigned int nr_egress_mappings;
180 struct vlan_priority_tci_mapping *egress_priority_map[16];
181
182 __be16 vlan_proto;
183 u16 vlan_id;
184 u16 flags;
185
186 struct net_device *real_dev;
187 netdevice_tracker dev_tracker;
188
189 unsigned char real_dev_addr[ETH_ALEN];
190
191 struct proc_dir_entry *dent;
192 struct vlan_pcpu_stats __percpu *vlan_pcpu_stats;
193#ifdef CONFIG_NET_POLL_CONTROLLER
194 struct netpoll *netpoll;
195#endif
196};
197
198static inline bool is_vlan_dev(const struct net_device *dev)
199{
200 return dev->priv_flags & IFF_802_1Q_VLAN;
201}
202
203static inline struct vlan_dev_priv *vlan_dev_priv(const struct net_device *dev)
204{
205 return netdev_priv(dev);
206}
207
208static inline u16
209vlan_dev_get_egress_qos_mask(struct net_device *dev, u32 skprio)
210{
211 struct vlan_priority_tci_mapping *mp;
212
213 smp_rmb(); /* coupled with smp_wmb() in vlan_dev_set_egress_priority() */
214
215 mp = vlan_dev_priv(dev)->egress_priority_map[(skprio & 0xF)];
216 while (mp) {
217 if (mp->priority == skprio) {
218 return mp->vlan_qos; /* This should already be shifted
219 * to mask correctly with the
220 * VLAN's TCI */
221 }
222 mp = mp->next;
223 }
224 return 0;
225}
226
227extern bool vlan_do_receive(struct sk_buff **skb);
228
229extern int vlan_vid_add(struct net_device *dev, __be16 proto, u16 vid);
230extern void vlan_vid_del(struct net_device *dev, __be16 proto, u16 vid);
231
232extern int vlan_vids_add_by_dev(struct net_device *dev,
233 const struct net_device *by_dev);
234extern void vlan_vids_del_by_dev(struct net_device *dev,
235 const struct net_device *by_dev);
236
237extern bool vlan_uses_dev(const struct net_device *dev);
238
239#else
240static inline bool is_vlan_dev(const struct net_device *dev)
241{
242 return false;
243}
244
245static inline struct net_device *
246__vlan_find_dev_deep_rcu(struct net_device *real_dev,
247 __be16 vlan_proto, u16 vlan_id)
248{
249 return NULL;
250}
251
252static inline int
253vlan_for_each(struct net_device *dev,
254 int (*action)(struct net_device *dev, int vid, void *arg),
255 void *arg)
256{
257 return 0;
258}
259
260static inline struct net_device *vlan_dev_real_dev(const struct net_device *dev)
261{
262 WARN_ON_ONCE(1);
263 return NULL;
264}
265
266static inline u16 vlan_dev_vlan_id(const struct net_device *dev)
267{
268 WARN_ON_ONCE(1);
269 return 0;
270}
271
272static inline __be16 vlan_dev_vlan_proto(const struct net_device *dev)
273{
274 WARN_ON_ONCE(1);
275 return 0;
276}
277
278static inline u16 vlan_dev_get_egress_qos_mask(struct net_device *dev,
279 u32 skprio)
280{
281 return 0;
282}
283
284static inline bool vlan_do_receive(struct sk_buff **skb)
285{
286 return false;
287}
288
289static inline int vlan_vid_add(struct net_device *dev, __be16 proto, u16 vid)
290{
291 return 0;
292}
293
294static inline void vlan_vid_del(struct net_device *dev, __be16 proto, u16 vid)
295{
296}
297
298static inline int vlan_vids_add_by_dev(struct net_device *dev,
299 const struct net_device *by_dev)
300{
301 return 0;
302}
303
304static inline void vlan_vids_del_by_dev(struct net_device *dev,
305 const struct net_device *by_dev)
306{
307}
308
309static inline bool vlan_uses_dev(const struct net_device *dev)
310{
311 return false;
312}
313#endif
314
315/**
316 * eth_type_vlan - check for valid vlan ether type.
317 * @ethertype: ether type to check
318 *
319 * Returns: true if the ether type is a vlan ether type.
320 */
321static inline bool eth_type_vlan(__be16 ethertype)
322{
323 switch (ethertype) {
324 case htons(ETH_P_8021Q):
325 case htons(ETH_P_8021AD):
326 return true;
327 default:
328 return false;
329 }
330}
331
332static inline bool vlan_hw_offload_capable(netdev_features_t features,
333 __be16 proto)
334{
335 if (proto == htons(ETH_P_8021Q) && features & NETIF_F_HW_VLAN_CTAG_TX)
336 return true;
337 if (proto == htons(ETH_P_8021AD) && features & NETIF_F_HW_VLAN_STAG_TX)
338 return true;
339 return false;
340}
341
342/**
343 * __vlan_insert_inner_tag - inner VLAN tag inserting
344 * @skb: skbuff to tag
345 * @vlan_proto: VLAN encapsulation protocol
346 * @vlan_tci: VLAN TCI to insert
347 * @mac_len: MAC header length including outer vlan headers
348 *
349 * Inserts the VLAN tag into @skb as part of the payload at offset mac_len
350 * Does not change skb->protocol so this function can be used during receive.
351 *
352 * Returns: error if skb_cow_head fails.
353 */
354static inline int __vlan_insert_inner_tag(struct sk_buff *skb,
355 __be16 vlan_proto, u16 vlan_tci,
356 unsigned int mac_len)
357{
358 const u8 meta_len = mac_len > ETH_TLEN ? skb_metadata_len(skb) : 0;
359 struct vlan_ethhdr *veth;
360
361 if (skb_cow_head(skb, headroom: meta_len + VLAN_HLEN) < 0)
362 return -ENOMEM;
363
364 skb_push(skb, VLAN_HLEN);
365
366 /* Move the mac header sans proto to the beginning of the new header. */
367 if (likely(mac_len > ETH_TLEN))
368 skb_postpush_data_move(skb, VLAN_HLEN, n: mac_len - ETH_TLEN);
369 if (skb_mac_header_was_set(skb))
370 skb->mac_header -= VLAN_HLEN;
371
372 veth = (struct vlan_ethhdr *)(skb->data + mac_len - ETH_HLEN);
373
374 /* first, the ethernet type */
375 if (likely(mac_len >= ETH_TLEN)) {
376 /* h_vlan_encapsulated_proto should already be populated, and
377 * skb->data has space for h_vlan_proto
378 */
379 veth->h_vlan_proto = vlan_proto;
380 } else {
381 /* h_vlan_encapsulated_proto should not be populated, and
382 * skb->data has no space for h_vlan_proto
383 */
384 veth->h_vlan_encapsulated_proto = skb->protocol;
385 }
386
387 /* now, the TCI */
388 veth->h_vlan_TCI = htons(vlan_tci);
389
390 return 0;
391}
392
393/**
394 * __vlan_insert_tag - regular VLAN tag inserting
395 * @skb: skbuff to tag
396 * @vlan_proto: VLAN encapsulation protocol
397 * @vlan_tci: VLAN TCI to insert
398 *
399 * Inserts the VLAN tag into @skb as part of the payload
400 * Does not change skb->protocol so this function can be used during receive.
401 *
402 * Returns: error if skb_cow_head fails.
403 */
404static inline int __vlan_insert_tag(struct sk_buff *skb,
405 __be16 vlan_proto, u16 vlan_tci)
406{
407 return __vlan_insert_inner_tag(skb, vlan_proto, vlan_tci, ETH_HLEN);
408}
409
410/**
411 * vlan_insert_inner_tag - inner VLAN tag inserting
412 * @skb: skbuff to tag
413 * @vlan_proto: VLAN encapsulation protocol
414 * @vlan_tci: VLAN TCI to insert
415 * @mac_len: MAC header length including outer vlan headers
416 *
417 * Inserts the VLAN tag into @skb as part of the payload at offset mac_len
418 * Returns a VLAN tagged skb. This might change skb->head.
419 *
420 * Following the skb_unshare() example, in case of error, the calling function
421 * doesn't have to worry about freeing the original skb.
422 *
423 * Does not change skb->protocol so this function can be used during receive.
424 *
425 * Return: modified @skb on success, NULL on error (@skb is freed).
426 */
427static inline struct sk_buff *vlan_insert_inner_tag(struct sk_buff *skb,
428 __be16 vlan_proto,
429 u16 vlan_tci,
430 unsigned int mac_len)
431{
432 int err;
433
434 err = __vlan_insert_inner_tag(skb, vlan_proto, vlan_tci, mac_len);
435 if (err) {
436 dev_kfree_skb_any(skb);
437 return NULL;
438 }
439 return skb;
440}
441
442/**
443 * vlan_insert_tag - regular VLAN tag inserting
444 * @skb: skbuff to tag
445 * @vlan_proto: VLAN encapsulation protocol
446 * @vlan_tci: VLAN TCI to insert
447 *
448 * Inserts the VLAN tag into @skb as part of the payload
449 * Returns a VLAN tagged skb. This might change skb->head.
450 *
451 * Following the skb_unshare() example, in case of error, the calling function
452 * doesn't have to worry about freeing the original skb.
453 *
454 * Does not change skb->protocol so this function can be used during receive.
455 *
456 * Return: modified @skb on success, NULL on error (@skb is freed).
457 */
458static inline struct sk_buff *vlan_insert_tag(struct sk_buff *skb,
459 __be16 vlan_proto, u16 vlan_tci)
460{
461 return vlan_insert_inner_tag(skb, vlan_proto, vlan_tci, ETH_HLEN);
462}
463
464/**
465 * vlan_insert_tag_set_proto - regular VLAN tag inserting
466 * @skb: skbuff to tag
467 * @vlan_proto: VLAN encapsulation protocol
468 * @vlan_tci: VLAN TCI to insert
469 *
470 * Inserts the VLAN tag into @skb as part of the payload
471 * Returns a VLAN tagged skb. This might change skb->head.
472 *
473 * Following the skb_unshare() example, in case of error, the calling function
474 * doesn't have to worry about freeing the original skb.
475 *
476 * Return: modified @skb on success, NULL on error (@skb is freed).
477 */
478static inline struct sk_buff *vlan_insert_tag_set_proto(struct sk_buff *skb,
479 __be16 vlan_proto,
480 u16 vlan_tci)
481{
482 skb = vlan_insert_tag(skb, vlan_proto, vlan_tci);
483 if (skb)
484 skb->protocol = vlan_proto;
485 return skb;
486}
487
488/**
489 * __vlan_hwaccel_clear_tag - clear hardware accelerated VLAN info
490 * @skb: skbuff to clear
491 *
492 * Clears the VLAN information from @skb
493 */
494static inline void __vlan_hwaccel_clear_tag(struct sk_buff *skb)
495{
496 skb->vlan_all = 0;
497}
498
499/**
500 * __vlan_hwaccel_copy_tag - copy hardware accelerated VLAN info from another skb
501 * @dst: skbuff to copy to
502 * @src: skbuff to copy from
503 *
504 * Copies VLAN information from @src to @dst (for branchless code)
505 */
506static inline void __vlan_hwaccel_copy_tag(struct sk_buff *dst, const struct sk_buff *src)
507{
508 dst->vlan_all = src->vlan_all;
509}
510
511/*
512 * __vlan_hwaccel_push_inside - pushes vlan tag to the payload
513 * @skb: skbuff to tag
514 *
515 * Pushes the VLAN tag from @skb->vlan_tci inside to the payload.
516 *
517 * Following the skb_unshare() example, in case of error, the calling function
518 * doesn't have to worry about freeing the original skb.
519 */
520static inline struct sk_buff *__vlan_hwaccel_push_inside(struct sk_buff *skb)
521{
522 skb = vlan_insert_tag_set_proto(skb, vlan_proto: skb->vlan_proto,
523 skb_vlan_tag_get(skb));
524 if (likely(skb))
525 __vlan_hwaccel_clear_tag(skb);
526 return skb;
527}
528
529/**
530 * __vlan_hwaccel_put_tag - hardware accelerated VLAN inserting
531 * @skb: skbuff to tag
532 * @vlan_proto: VLAN encapsulation protocol
533 * @vlan_tci: VLAN TCI to insert
534 *
535 * Puts the VLAN TCI in @skb->vlan_tci and lets the device do the rest
536 */
537static inline void __vlan_hwaccel_put_tag(struct sk_buff *skb,
538 __be16 vlan_proto, u16 vlan_tci)
539{
540 skb->vlan_proto = vlan_proto;
541 skb->vlan_tci = vlan_tci;
542}
543
544/**
545 * __vlan_get_tag - get the VLAN ID that is part of the payload
546 * @skb: skbuff to query
547 * @vlan_tci: buffer to store value
548 *
549 * Returns: error if the skb is not of VLAN type
550 */
551static inline int __vlan_get_tag(const struct sk_buff *skb, u16 *vlan_tci)
552{
553 struct vlan_ethhdr *veth = skb_vlan_eth_hdr(skb);
554
555 if (!eth_type_vlan(ethertype: veth->h_vlan_proto))
556 return -ENODATA;
557
558 *vlan_tci = ntohs(veth->h_vlan_TCI);
559 return 0;
560}
561
562/**
563 * __vlan_hwaccel_get_tag - get the VLAN ID that is in @skb->cb[]
564 * @skb: skbuff to query
565 * @vlan_tci: buffer to store value
566 *
567 * Returns: error if @skb->vlan_tci is not set correctly
568 */
569static inline int __vlan_hwaccel_get_tag(const struct sk_buff *skb,
570 u16 *vlan_tci)
571{
572 if (skb_vlan_tag_present(skb)) {
573 *vlan_tci = skb_vlan_tag_get(skb);
574 return 0;
575 } else {
576 *vlan_tci = 0;
577 return -ENODATA;
578 }
579}
580
581/**
582 * vlan_get_tag - get the VLAN ID from the skb
583 * @skb: skbuff to query
584 * @vlan_tci: buffer to store value
585 *
586 * Returns: error if the skb is not VLAN tagged
587 */
588static inline int vlan_get_tag(const struct sk_buff *skb, u16 *vlan_tci)
589{
590 if (skb->dev->features & NETIF_F_HW_VLAN_CTAG_TX) {
591 return __vlan_hwaccel_get_tag(skb, vlan_tci);
592 } else {
593 return __vlan_get_tag(skb, vlan_tci);
594 }
595}
596
597/**
598 * __vlan_get_protocol_offset() - get protocol EtherType.
599 * @skb: skbuff to query
600 * @type: first vlan protocol
601 * @mac_offset: MAC offset
602 * @depth: buffer to store length of eth and vlan tags in bytes
603 *
604 * Returns: the EtherType of the packet, regardless of whether it is
605 * vlan encapsulated (normal or hardware accelerated) or not.
606 */
607static inline __be16 __vlan_get_protocol_offset(const struct sk_buff *skb,
608 __be16 type,
609 int mac_offset,
610 int *depth)
611{
612 unsigned int vlan_depth = skb->mac_len, parse_depth = VLAN_MAX_DEPTH;
613
614 /* if type is 802.1Q/AD then the header should already be
615 * present at mac_len - VLAN_HLEN (if mac_len > 0), or at
616 * ETH_HLEN otherwise
617 */
618 if (eth_type_vlan(ethertype: type)) {
619 if (vlan_depth) {
620 if (WARN_ON(vlan_depth < VLAN_HLEN))
621 return 0;
622 vlan_depth -= VLAN_HLEN;
623 } else {
624 vlan_depth = ETH_HLEN;
625 }
626 do {
627 struct vlan_hdr vhdr, *vh;
628
629 vh = skb_header_pointer(skb, offset: mac_offset + vlan_depth,
630 len: sizeof(vhdr), buffer: &vhdr);
631 if (unlikely(!vh || !--parse_depth))
632 return 0;
633
634 type = vh->h_vlan_encapsulated_proto;
635 vlan_depth += VLAN_HLEN;
636 } while (eth_type_vlan(ethertype: type));
637 }
638
639 if (depth)
640 *depth = vlan_depth;
641
642 return type;
643}
644
645static inline __be16 __vlan_get_protocol(const struct sk_buff *skb, __be16 type,
646 int *depth)
647{
648 return __vlan_get_protocol_offset(skb, type, mac_offset: 0, depth);
649}
650
651/**
652 * vlan_get_protocol - get protocol EtherType.
653 * @skb: skbuff to query
654 *
655 * Returns: the EtherType of the packet, regardless of whether it is
656 * vlan encapsulated (normal or hardware accelerated) or not.
657 */
658static inline __be16 vlan_get_protocol(const struct sk_buff *skb)
659{
660 return __vlan_get_protocol(skb, type: skb->protocol, NULL);
661}
662
663/* This version of __vlan_get_protocol() also pulls mac header in skb->head */
664static inline __be16 vlan_get_protocol_and_depth(struct sk_buff *skb,
665 __be16 type, int *depth)
666{
667 int maclen;
668
669 type = __vlan_get_protocol(skb, type, depth: &maclen);
670
671 if (type) {
672 if (!pskb_may_pull(skb, len: maclen))
673 type = 0;
674 else if (depth)
675 *depth = maclen;
676 }
677 return type;
678}
679
680/* A getter for the SKB protocol field which will handle VLAN tags consistently
681 * whether VLAN acceleration is enabled or not.
682 */
683static inline __be16 skb_protocol(const struct sk_buff *skb, bool skip_vlan)
684{
685 if (!skip_vlan)
686 /* VLAN acceleration strips the VLAN header from the skb and
687 * moves it to skb->vlan_proto
688 */
689 return skb_vlan_tag_present(skb) ? skb->vlan_proto : skb->protocol;
690
691 return vlan_get_protocol(skb);
692}
693
694static inline void vlan_set_encap_proto(struct sk_buff *skb,
695 struct vlan_hdr *vhdr)
696{
697 __be16 proto;
698 unsigned short *rawp;
699
700 /*
701 * Was a VLAN packet, grab the encapsulated protocol, which the layer
702 * three protocols care about.
703 */
704
705 proto = vhdr->h_vlan_encapsulated_proto;
706 if (eth_proto_is_802_3(proto)) {
707 skb->protocol = proto;
708 return;
709 }
710
711 rawp = (unsigned short *)(vhdr + 1);
712 if (*rawp == 0xFFFF)
713 /*
714 * This is a magic hack to spot IPX packets. Older Novell
715 * breaks the protocol design and runs IPX over 802.3 without
716 * an 802.2 LLC layer. We look for FFFF which isn't a used
717 * 802.2 SSAP/DSAP. This won't work for fault tolerant netware
718 * but does for the rest.
719 */
720 skb->protocol = htons(ETH_P_802_3);
721 else
722 /*
723 * Real 802.2 LLC
724 */
725 skb->protocol = htons(ETH_P_802_2);
726}
727
728/**
729 * vlan_remove_tag - remove outer VLAN tag from payload
730 * @skb: skbuff to remove tag from
731 * @vlan_tci: buffer to store value
732 *
733 * Expects the skb to contain a VLAN tag in the payload, and to have skb->data
734 * pointing at the MAC header.
735 */
736static inline void vlan_remove_tag(struct sk_buff *skb, u16 *vlan_tci)
737{
738 struct vlan_hdr *vhdr = (struct vlan_hdr *)(skb->data + ETH_HLEN);
739
740 *vlan_tci = ntohs(vhdr->h_vlan_TCI);
741
742 vlan_set_encap_proto(skb, vhdr);
743 __skb_pull(skb, VLAN_HLEN);
744 skb_postpull_data_move(skb, VLAN_HLEN, n: 2 * ETH_ALEN);
745}
746
747/**
748 * skb_vlan_tagged - check if skb is vlan tagged.
749 * @skb: skbuff to query
750 *
751 * Returns: true if the skb is tagged, regardless of whether it is hardware
752 * accelerated or not.
753 */
754static inline bool skb_vlan_tagged(const struct sk_buff *skb)
755{
756 if (!skb_vlan_tag_present(skb) &&
757 likely(!eth_type_vlan(skb->protocol)))
758 return false;
759
760 return true;
761}
762
763/**
764 * skb_vlan_tagged_multi - check if skb is vlan tagged with multiple headers.
765 * @skb: skbuff to query
766 *
767 * Returns: true if the skb is tagged with multiple vlan headers, regardless
768 * of whether it is hardware accelerated or not.
769 */
770static inline bool skb_vlan_tagged_multi(struct sk_buff *skb)
771{
772 __be16 protocol = skb->protocol;
773
774 if (!skb_vlan_tag_present(skb)) {
775 struct vlan_ethhdr *veh;
776
777 if (likely(!eth_type_vlan(protocol)))
778 return false;
779
780 if (unlikely(!pskb_may_pull(skb, VLAN_ETH_HLEN)))
781 return false;
782
783 veh = skb_vlan_eth_hdr(skb);
784 protocol = veh->h_vlan_encapsulated_proto;
785 }
786
787 if (!eth_type_vlan(ethertype: protocol))
788 return false;
789
790 return true;
791}
792
793/**
794 * vlan_features_check - drop unsafe features for skb with multiple tags.
795 * @skb: skbuff to query
796 * @features: features to be checked
797 *
798 * Returns: features without unsafe ones if the skb has multiple tags.
799 */
800static inline netdev_features_t vlan_features_check(struct sk_buff *skb,
801 netdev_features_t features)
802{
803 if (skb_vlan_tagged_multi(skb)) {
804 /* In the case of multi-tagged packets, use a direct mask
805 * instead of using netdev_interesect_features(), to make
806 * sure that only devices supporting NETIF_F_HW_CSUM will
807 * have checksum offloading support.
808 */
809 features &= NETIF_F_SG | NETIF_F_HIGHDMA | NETIF_F_HW_CSUM |
810 NETIF_F_FRAGLIST | NETIF_F_HW_VLAN_CTAG_TX |
811 NETIF_F_HW_VLAN_STAG_TX;
812 }
813
814 return features;
815}
816
817/**
818 * compare_vlan_header - Compare two vlan headers
819 * @h1: Pointer to vlan header
820 * @h2: Pointer to vlan header
821 *
822 * Compare two vlan headers.
823 *
824 * Please note that alignment of h1 & h2 are only guaranteed to be 16 bits.
825 *
826 * Return: 0 if equal, arbitrary non-zero value if not equal.
827 */
828static inline unsigned long compare_vlan_header(const struct vlan_hdr *h1,
829 const struct vlan_hdr *h2)
830{
831#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
832 return *(u32 *)h1 ^ *(u32 *)h2;
833#else
834 return ((__force u32)h1->h_vlan_TCI ^ (__force u32)h2->h_vlan_TCI) |
835 ((__force u32)h1->h_vlan_encapsulated_proto ^
836 (__force u32)h2->h_vlan_encapsulated_proto);
837#endif
838}
839#endif /* !(_LINUX_IF_VLAN_H_) */
840

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