xref: /linux/include/linux/if_vlan.h (revision 2455f0e124d317dd08d337a7550a78a224d4ba41)
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  */
35 struct 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  */
48 struct 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 
60 static 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 */
72 extern void vlan_ioctl_set(int (*hook)(struct net *, void __user *));
73 
74 static 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_all)
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 
85 static 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 
91 static 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 
97 static 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 
103 static 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  */
120 struct 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 
133 extern struct net_device *__vlan_find_dev_deep_rcu(struct net_device *real_dev,
134 					       __be16 vlan_proto, u16 vlan_id);
135 extern int vlan_for_each(struct net_device *dev,
136 			 int (*action)(struct net_device *dev, int vid,
137 				       void *arg), void *arg);
138 extern struct net_device *vlan_dev_real_dev(const struct net_device *dev);
139 extern u16 vlan_dev_vlan_id(const struct net_device *dev);
140 extern __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  */
148 struct vlan_priority_tci_mapping {
149 	u32					priority;
150 	u16					vlan_qos;
151 	struct vlan_priority_tci_mapping	*next;
152 };
153 
154 struct proc_dir_entry;
155 struct 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  */
172 struct 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 
194 static inline struct vlan_dev_priv *vlan_dev_priv(const struct net_device *dev)
195 {
196 	return netdev_priv(dev);
197 }
198 
199 static inline u16
200 vlan_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 
218 extern bool vlan_do_receive(struct sk_buff **skb);
219 
220 extern int vlan_vid_add(struct net_device *dev, __be16 proto, u16 vid);
221 extern void vlan_vid_del(struct net_device *dev, __be16 proto, u16 vid);
222 
223 extern int vlan_vids_add_by_dev(struct net_device *dev,
224 				const struct net_device *by_dev);
225 extern void vlan_vids_del_by_dev(struct net_device *dev,
226 				 const struct net_device *by_dev);
227 
228 extern bool vlan_uses_dev(const struct net_device *dev);
229 
230 #else
231 static 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 
238 static inline int
239 vlan_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 
246 static inline struct net_device *vlan_dev_real_dev(const struct net_device *dev)
247 {
248 	BUG();
249 	return NULL;
250 }
251 
252 static inline u16 vlan_dev_vlan_id(const struct net_device *dev)
253 {
254 	BUG();
255 	return 0;
256 }
257 
258 static inline __be16 vlan_dev_vlan_proto(const struct net_device *dev)
259 {
260 	BUG();
261 	return 0;
262 }
263 
264 static inline u16 vlan_dev_get_egress_qos_mask(struct net_device *dev,
265 					       u32 skprio)
266 {
267 	return 0;
268 }
269 
270 static inline bool vlan_do_receive(struct sk_buff **skb)
271 {
272 	return false;
273 }
274 
275 static inline int vlan_vid_add(struct net_device *dev, __be16 proto, u16 vid)
276 {
277 	return 0;
278 }
279 
280 static inline void vlan_vid_del(struct net_device *dev, __be16 proto, u16 vid)
281 {
282 }
283 
284 static inline int vlan_vids_add_by_dev(struct net_device *dev,
285 				       const struct net_device *by_dev)
286 {
287 	return 0;
288 }
289 
290 static inline void vlan_vids_del_by_dev(struct net_device *dev,
291 					const struct net_device *by_dev)
292 {
293 }
294 
295 static 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  */
307 static 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 
318 static 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  */
340 static 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  */
388 static 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  */
409 static 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  */
438 static 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  */
456 static 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  */
472 static inline void __vlan_hwaccel_clear_tag(struct sk_buff *skb)
473 {
474 	skb->vlan_all = 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  */
484 static inline void __vlan_hwaccel_copy_tag(struct sk_buff *dst, const struct sk_buff *src)
485 {
486 	dst->vlan_all = src->vlan_all;
487 }
488 
489 /*
490  * __vlan_hwaccel_push_inside - pushes vlan tag to the payload
491  * @skb: skbuff to tag
492  *
493  * Pushes the VLAN tag from @skb->vlan_tci inside to the payload.
494  *
495  * Following the skb_unshare() example, in case of error, the calling function
496  * doesn't have to worry about freeing the original skb.
497  */
498 static inline struct sk_buff *__vlan_hwaccel_push_inside(struct sk_buff *skb)
499 {
500 	skb = vlan_insert_tag_set_proto(skb, skb->vlan_proto,
501 					skb_vlan_tag_get(skb));
502 	if (likely(skb))
503 		__vlan_hwaccel_clear_tag(skb);
504 	return skb;
505 }
506 
507 /**
508  * __vlan_hwaccel_put_tag - hardware accelerated VLAN inserting
509  * @skb: skbuff to tag
510  * @vlan_proto: VLAN encapsulation protocol
511  * @vlan_tci: VLAN TCI to insert
512  *
513  * Puts the VLAN TCI in @skb->vlan_tci and lets the device do the rest
514  */
515 static inline void __vlan_hwaccel_put_tag(struct sk_buff *skb,
516 					  __be16 vlan_proto, u16 vlan_tci)
517 {
518 	skb->vlan_proto = vlan_proto;
519 	skb->vlan_tci = vlan_tci;
520 }
521 
522 /**
523  * __vlan_get_tag - get the VLAN ID that is part of the payload
524  * @skb: skbuff to query
525  * @vlan_tci: buffer to store value
526  *
527  * Returns error if the skb is not of VLAN type
528  */
529 static inline int __vlan_get_tag(const struct sk_buff *skb, u16 *vlan_tci)
530 {
531 	struct vlan_ethhdr *veth = (struct vlan_ethhdr *)skb->data;
532 
533 	if (!eth_type_vlan(veth->h_vlan_proto))
534 		return -EINVAL;
535 
536 	*vlan_tci = ntohs(veth->h_vlan_TCI);
537 	return 0;
538 }
539 
540 /**
541  * __vlan_hwaccel_get_tag - get the VLAN ID that is in @skb->cb[]
542  * @skb: skbuff to query
543  * @vlan_tci: buffer to store value
544  *
545  * Returns error if @skb->vlan_tci is not set correctly
546  */
547 static inline int __vlan_hwaccel_get_tag(const struct sk_buff *skb,
548 					 u16 *vlan_tci)
549 {
550 	if (skb_vlan_tag_present(skb)) {
551 		*vlan_tci = skb_vlan_tag_get(skb);
552 		return 0;
553 	} else {
554 		*vlan_tci = 0;
555 		return -EINVAL;
556 	}
557 }
558 
559 /**
560  * vlan_get_tag - get the VLAN ID from the skb
561  * @skb: skbuff to query
562  * @vlan_tci: buffer to store value
563  *
564  * Returns error if the skb is not VLAN tagged
565  */
566 static inline int vlan_get_tag(const struct sk_buff *skb, u16 *vlan_tci)
567 {
568 	if (skb->dev->features & NETIF_F_HW_VLAN_CTAG_TX) {
569 		return __vlan_hwaccel_get_tag(skb, vlan_tci);
570 	} else {
571 		return __vlan_get_tag(skb, vlan_tci);
572 	}
573 }
574 
575 /**
576  * vlan_get_protocol - get protocol EtherType.
577  * @skb: skbuff to query
578  * @type: first vlan protocol
579  * @depth: buffer to store length of eth and vlan tags in bytes
580  *
581  * Returns the EtherType of the packet, regardless of whether it is
582  * vlan encapsulated (normal or hardware accelerated) or not.
583  */
584 static inline __be16 __vlan_get_protocol(const struct sk_buff *skb, __be16 type,
585 					 int *depth)
586 {
587 	unsigned int vlan_depth = skb->mac_len, parse_depth = VLAN_MAX_DEPTH;
588 
589 	/* if type is 802.1Q/AD then the header should already be
590 	 * present at mac_len - VLAN_HLEN (if mac_len > 0), or at
591 	 * ETH_HLEN otherwise
592 	 */
593 	if (eth_type_vlan(type)) {
594 		if (vlan_depth) {
595 			if (WARN_ON(vlan_depth < VLAN_HLEN))
596 				return 0;
597 			vlan_depth -= VLAN_HLEN;
598 		} else {
599 			vlan_depth = ETH_HLEN;
600 		}
601 		do {
602 			struct vlan_hdr vhdr, *vh;
603 
604 			vh = skb_header_pointer(skb, vlan_depth, sizeof(vhdr), &vhdr);
605 			if (unlikely(!vh || !--parse_depth))
606 				return 0;
607 
608 			type = vh->h_vlan_encapsulated_proto;
609 			vlan_depth += VLAN_HLEN;
610 		} while (eth_type_vlan(type));
611 	}
612 
613 	if (depth)
614 		*depth = vlan_depth;
615 
616 	return type;
617 }
618 
619 /**
620  * vlan_get_protocol - get protocol EtherType.
621  * @skb: skbuff to query
622  *
623  * Returns the EtherType of the packet, regardless of whether it is
624  * vlan encapsulated (normal or hardware accelerated) or not.
625  */
626 static inline __be16 vlan_get_protocol(const struct sk_buff *skb)
627 {
628 	return __vlan_get_protocol(skb, skb->protocol, NULL);
629 }
630 
631 /* A getter for the SKB protocol field which will handle VLAN tags consistently
632  * whether VLAN acceleration is enabled or not.
633  */
634 static inline __be16 skb_protocol(const struct sk_buff *skb, bool skip_vlan)
635 {
636 	if (!skip_vlan)
637 		/* VLAN acceleration strips the VLAN header from the skb and
638 		 * moves it to skb->vlan_proto
639 		 */
640 		return skb_vlan_tag_present(skb) ? skb->vlan_proto : skb->protocol;
641 
642 	return vlan_get_protocol(skb);
643 }
644 
645 static inline void vlan_set_encap_proto(struct sk_buff *skb,
646 					struct vlan_hdr *vhdr)
647 {
648 	__be16 proto;
649 	unsigned short *rawp;
650 
651 	/*
652 	 * Was a VLAN packet, grab the encapsulated protocol, which the layer
653 	 * three protocols care about.
654 	 */
655 
656 	proto = vhdr->h_vlan_encapsulated_proto;
657 	if (eth_proto_is_802_3(proto)) {
658 		skb->protocol = proto;
659 		return;
660 	}
661 
662 	rawp = (unsigned short *)(vhdr + 1);
663 	if (*rawp == 0xFFFF)
664 		/*
665 		 * This is a magic hack to spot IPX packets. Older Novell
666 		 * breaks the protocol design and runs IPX over 802.3 without
667 		 * an 802.2 LLC layer. We look for FFFF which isn't a used
668 		 * 802.2 SSAP/DSAP. This won't work for fault tolerant netware
669 		 * but does for the rest.
670 		 */
671 		skb->protocol = htons(ETH_P_802_3);
672 	else
673 		/*
674 		 * Real 802.2 LLC
675 		 */
676 		skb->protocol = htons(ETH_P_802_2);
677 }
678 
679 /**
680  * skb_vlan_tagged - check if skb is vlan tagged.
681  * @skb: skbuff to query
682  *
683  * Returns true if the skb is tagged, regardless of whether it is hardware
684  * accelerated or not.
685  */
686 static inline bool skb_vlan_tagged(const struct sk_buff *skb)
687 {
688 	if (!skb_vlan_tag_present(skb) &&
689 	    likely(!eth_type_vlan(skb->protocol)))
690 		return false;
691 
692 	return true;
693 }
694 
695 /**
696  * skb_vlan_tagged_multi - check if skb is vlan tagged with multiple headers.
697  * @skb: skbuff to query
698  *
699  * Returns true if the skb is tagged with multiple vlan headers, regardless
700  * of whether it is hardware accelerated or not.
701  */
702 static inline bool skb_vlan_tagged_multi(struct sk_buff *skb)
703 {
704 	__be16 protocol = skb->protocol;
705 
706 	if (!skb_vlan_tag_present(skb)) {
707 		struct vlan_ethhdr *veh;
708 
709 		if (likely(!eth_type_vlan(protocol)))
710 			return false;
711 
712 		if (unlikely(!pskb_may_pull(skb, VLAN_ETH_HLEN)))
713 			return false;
714 
715 		veh = (struct vlan_ethhdr *)skb->data;
716 		protocol = veh->h_vlan_encapsulated_proto;
717 	}
718 
719 	if (!eth_type_vlan(protocol))
720 		return false;
721 
722 	return true;
723 }
724 
725 /**
726  * vlan_features_check - drop unsafe features for skb with multiple tags.
727  * @skb: skbuff to query
728  * @features: features to be checked
729  *
730  * Returns features without unsafe ones if the skb has multiple tags.
731  */
732 static inline netdev_features_t vlan_features_check(struct sk_buff *skb,
733 						    netdev_features_t features)
734 {
735 	if (skb_vlan_tagged_multi(skb)) {
736 		/* In the case of multi-tagged packets, use a direct mask
737 		 * instead of using netdev_interesect_features(), to make
738 		 * sure that only devices supporting NETIF_F_HW_CSUM will
739 		 * have checksum offloading support.
740 		 */
741 		features &= NETIF_F_SG | NETIF_F_HIGHDMA | NETIF_F_HW_CSUM |
742 			    NETIF_F_FRAGLIST | NETIF_F_HW_VLAN_CTAG_TX |
743 			    NETIF_F_HW_VLAN_STAG_TX;
744 	}
745 
746 	return features;
747 }
748 
749 /**
750  * compare_vlan_header - Compare two vlan headers
751  * @h1: Pointer to vlan header
752  * @h2: Pointer to vlan header
753  *
754  * Compare two vlan headers, returns 0 if equal.
755  *
756  * Please note that alignment of h1 & h2 are only guaranteed to be 16 bits.
757  */
758 static inline unsigned long compare_vlan_header(const struct vlan_hdr *h1,
759 						const struct vlan_hdr *h2)
760 {
761 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
762 	return *(u32 *)h1 ^ *(u32 *)h2;
763 #else
764 	return ((__force u32)h1->h_vlan_TCI ^ (__force u32)h2->h_vlan_TCI) |
765 	       ((__force u32)h1->h_vlan_encapsulated_proto ^
766 		(__force u32)h2->h_vlan_encapsulated_proto);
767 #endif
768 }
769 #endif /* !(_LINUX_IF_VLAN_H_) */
770