if_vlan.h

  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(call_netdevice_notifiers(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(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(call_netdevice_notifiers(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(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, 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, 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, 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(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(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, mac_offset + vlan_depth,
630						sizeof(vhdr), &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(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, 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, 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, &maclen);
670
671	if (type) {
672		if (!pskb_may_pull(skb, 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, 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(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_) */