linux/include/linux/if_vlan.h
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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        unsigned char   h_dest[ETH_ALEN];
  50        unsigned char   h_source[ETH_ALEN];
  51        __be16          h_vlan_proto;
  52        __be16          h_vlan_TCI;
  53        __be16          h_vlan_encapsulated_proto;
  54};
  55
  56#include <linux/skbuff.h>
  57
  58static inline struct vlan_ethhdr *vlan_eth_hdr(const struct sk_buff *skb)
  59{
  60        return (struct vlan_ethhdr *)skb_mac_header(skb);
  61}
  62
  63#define VLAN_PRIO_MASK          0xe000 /* Priority Code Point */
  64#define VLAN_PRIO_SHIFT         13
  65#define VLAN_CFI_MASK           0x1000 /* Canonical Format Indicator / Drop Eligible Indicator */
  66#define VLAN_VID_MASK           0x0fff /* VLAN Identifier */
  67#define VLAN_N_VID              4096
  68
  69/* found in socket.c */
  70extern void vlan_ioctl_set(int (*hook)(struct net *, void __user *));
  71
  72static inline bool is_vlan_dev(const struct net_device *dev)
  73{
  74        return dev->priv_flags & IFF_802_1Q_VLAN;
  75}
  76
  77#define skb_vlan_tag_present(__skb)     ((__skb)->vlan_present)
  78#define skb_vlan_tag_get(__skb)         ((__skb)->vlan_tci)
  79#define skb_vlan_tag_get_id(__skb)      ((__skb)->vlan_tci & VLAN_VID_MASK)
  80#define skb_vlan_tag_get_cfi(__skb)     (!!((__skb)->vlan_tci & VLAN_CFI_MASK))
  81#define skb_vlan_tag_get_prio(__skb)    (((__skb)->vlan_tci & VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT)
  82
  83static inline int vlan_get_rx_ctag_filter_info(struct net_device *dev)
  84{
  85        ASSERT_RTNL();
  86        return notifier_to_errno(call_netdevice_notifiers(NETDEV_CVLAN_FILTER_PUSH_INFO, dev));
  87}
  88
  89static inline void vlan_drop_rx_ctag_filter_info(struct net_device *dev)
  90{
  91        ASSERT_RTNL();
  92        call_netdevice_notifiers(NETDEV_CVLAN_FILTER_DROP_INFO, dev);
  93}
  94
  95static inline int vlan_get_rx_stag_filter_info(struct net_device *dev)
  96{
  97        ASSERT_RTNL();
  98        return notifier_to_errno(call_netdevice_notifiers(NETDEV_SVLAN_FILTER_PUSH_INFO, dev));
  99}
 100
 101static inline void vlan_drop_rx_stag_filter_info(struct net_device *dev)
 102{
 103        ASSERT_RTNL();
 104        call_netdevice_notifiers(NETDEV_SVLAN_FILTER_DROP_INFO, dev);
 105}
 106
 107/**
 108 *      struct vlan_pcpu_stats - VLAN percpu rx/tx stats
 109 *      @rx_packets: number of received packets
 110 *      @rx_bytes: number of received bytes
 111 *      @rx_multicast: number of received multicast packets
 112 *      @tx_packets: number of transmitted packets
 113 *      @tx_bytes: number of transmitted bytes
 114 *      @syncp: synchronization point for 64bit counters
 115 *      @rx_errors: number of rx errors
 116 *      @tx_dropped: number of tx drops
 117 */
 118struct vlan_pcpu_stats {
 119        u64                     rx_packets;
 120        u64                     rx_bytes;
 121        u64                     rx_multicast;
 122        u64                     tx_packets;
 123        u64                     tx_bytes;
 124        struct u64_stats_sync   syncp;
 125        u32                     rx_errors;
 126        u32                     tx_dropped;
 127};
 128
 129#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
 130
 131extern struct net_device *__vlan_find_dev_deep_rcu(struct net_device *real_dev,
 132                                               __be16 vlan_proto, u16 vlan_id);
 133extern int vlan_for_each(struct net_device *dev,
 134                         int (*action)(struct net_device *dev, int vid,
 135                                       void *arg), void *arg);
 136extern struct net_device *vlan_dev_real_dev(const struct net_device *dev);
 137extern u16 vlan_dev_vlan_id(const struct net_device *dev);
 138extern __be16 vlan_dev_vlan_proto(const struct net_device *dev);
 139
 140/**
 141 *      struct vlan_priority_tci_mapping - vlan egress priority mappings
 142 *      @priority: skb priority
 143 *      @vlan_qos: vlan priority: (skb->priority << 13) & 0xE000
 144 *      @next: pointer to next struct
 145 */
 146struct vlan_priority_tci_mapping {
 147        u32                                     priority;
 148        u16                                     vlan_qos;
 149        struct vlan_priority_tci_mapping        *next;
 150};
 151
 152struct proc_dir_entry;
 153struct netpoll;
 154
 155/**
 156 *      struct vlan_dev_priv - VLAN private device data
 157 *      @nr_ingress_mappings: number of ingress priority mappings
 158 *      @ingress_priority_map: ingress priority mappings
 159 *      @nr_egress_mappings: number of egress priority mappings
 160 *      @egress_priority_map: hash of egress priority mappings
 161 *      @vlan_proto: VLAN encapsulation protocol
 162 *      @vlan_id: VLAN identifier
 163 *      @flags: device flags
 164 *      @real_dev: underlying netdevice
 165 *      @real_dev_addr: address of underlying netdevice
 166 *      @dent: proc dir entry
 167 *      @vlan_pcpu_stats: ptr to percpu rx stats
 168 */
 169struct vlan_dev_priv {
 170        unsigned int                            nr_ingress_mappings;
 171        u32                                     ingress_priority_map[8];
 172        unsigned int                            nr_egress_mappings;
 173        struct vlan_priority_tci_mapping        *egress_priority_map[16];
 174
 175        __be16                                  vlan_proto;
 176        u16                                     vlan_id;
 177        u16                                     flags;
 178
 179        struct net_device                       *real_dev;
 180        unsigned char                           real_dev_addr[ETH_ALEN];
 181
 182        struct proc_dir_entry                   *dent;
 183        struct vlan_pcpu_stats __percpu         *vlan_pcpu_stats;
 184#ifdef CONFIG_NET_POLL_CONTROLLER
 185        struct netpoll                          *netpoll;
 186#endif
 187};
 188
 189static inline struct vlan_dev_priv *vlan_dev_priv(const struct net_device *dev)
 190{
 191        return netdev_priv(dev);
 192}
 193
 194static inline u16
 195vlan_dev_get_egress_qos_mask(struct net_device *dev, u32 skprio)
 196{
 197        struct vlan_priority_tci_mapping *mp;
 198
 199        smp_rmb(); /* coupled with smp_wmb() in vlan_dev_set_egress_priority() */
 200
 201        mp = vlan_dev_priv(dev)->egress_priority_map[(skprio & 0xF)];
 202        while (mp) {
 203                if (mp->priority == skprio) {
 204                        return mp->vlan_qos; /* This should already be shifted
 205                                              * to mask correctly with the
 206                                              * VLAN's TCI */
 207                }
 208                mp = mp->next;
 209        }
 210        return 0;
 211}
 212
 213extern bool vlan_do_receive(struct sk_buff **skb);
 214
 215extern int vlan_vid_add(struct net_device *dev, __be16 proto, u16 vid);
 216extern void vlan_vid_del(struct net_device *dev, __be16 proto, u16 vid);
 217
 218extern int vlan_vids_add_by_dev(struct net_device *dev,
 219                                const struct net_device *by_dev);
 220extern void vlan_vids_del_by_dev(struct net_device *dev,
 221                                 const struct net_device *by_dev);
 222
 223extern bool vlan_uses_dev(const struct net_device *dev);
 224
 225#else
 226static inline struct net_device *
 227__vlan_find_dev_deep_rcu(struct net_device *real_dev,
 228                     __be16 vlan_proto, u16 vlan_id)
 229{
 230        return NULL;
 231}
 232
 233static inline int
 234vlan_for_each(struct net_device *dev,
 235              int (*action)(struct net_device *dev, int vid, void *arg),
 236              void *arg)
 237{
 238        return 0;
 239}
 240
 241static inline struct net_device *vlan_dev_real_dev(const struct net_device *dev)
 242{
 243        BUG();
 244        return NULL;
 245}
 246
 247static inline u16 vlan_dev_vlan_id(const struct net_device *dev)
 248{
 249        BUG();
 250        return 0;
 251}
 252
 253static inline __be16 vlan_dev_vlan_proto(const struct net_device *dev)
 254{
 255        BUG();
 256        return 0;
 257}
 258
 259static inline u16 vlan_dev_get_egress_qos_mask(struct net_device *dev,
 260                                               u32 skprio)
 261{
 262        return 0;
 263}
 264
 265static inline bool vlan_do_receive(struct sk_buff **skb)
 266{
 267        return false;
 268}
 269
 270static inline int vlan_vid_add(struct net_device *dev, __be16 proto, u16 vid)
 271{
 272        return 0;
 273}
 274
 275static inline void vlan_vid_del(struct net_device *dev, __be16 proto, u16 vid)
 276{
 277}
 278
 279static inline int vlan_vids_add_by_dev(struct net_device *dev,
 280                                       const struct net_device *by_dev)
 281{
 282        return 0;
 283}
 284
 285static inline void vlan_vids_del_by_dev(struct net_device *dev,
 286                                        const struct net_device *by_dev)
 287{
 288}
 289
 290static inline bool vlan_uses_dev(const struct net_device *dev)
 291{
 292        return false;
 293}
 294#endif
 295
 296/**
 297 * eth_type_vlan - check for valid vlan ether type.
 298 * @ethertype: ether type to check
 299 *
 300 * Returns true if the ether type is a vlan ether type.
 301 */
 302static inline bool eth_type_vlan(__be16 ethertype)
 303{
 304        switch (ethertype) {
 305        case htons(ETH_P_8021Q):
 306        case htons(ETH_P_8021AD):
 307                return true;
 308        default:
 309                return false;
 310        }
 311}
 312
 313static inline bool vlan_hw_offload_capable(netdev_features_t features,
 314                                           __be16 proto)
 315{
 316        if (proto == htons(ETH_P_8021Q) && features & NETIF_F_HW_VLAN_CTAG_TX)
 317                return true;
 318        if (proto == htons(ETH_P_8021AD) && features & NETIF_F_HW_VLAN_STAG_TX)
 319                return true;
 320        return false;
 321}
 322
 323/**
 324 * __vlan_insert_inner_tag - inner VLAN tag inserting
 325 * @skb: skbuff to tag
 326 * @vlan_proto: VLAN encapsulation protocol
 327 * @vlan_tci: VLAN TCI to insert
 328 * @mac_len: MAC header length including outer vlan headers
 329 *
 330 * Inserts the VLAN tag into @skb as part of the payload at offset mac_len
 331 * Returns error if skb_cow_head fails.
 332 *
 333 * Does not change skb->protocol so this function can be used during receive.
 334 */
 335static inline int __vlan_insert_inner_tag(struct sk_buff *skb,
 336                                          __be16 vlan_proto, u16 vlan_tci,
 337                                          unsigned int mac_len)
 338{
 339        struct vlan_ethhdr *veth;
 340
 341        if (skb_cow_head(skb, VLAN_HLEN) < 0)
 342                return -ENOMEM;
 343
 344        skb_push(skb, VLAN_HLEN);
 345
 346        /* Move the mac header sans proto to the beginning of the new header. */
 347        if (likely(mac_len > ETH_TLEN))
 348                memmove(skb->data, skb->data + VLAN_HLEN, mac_len - ETH_TLEN);
 349        skb->mac_header -= VLAN_HLEN;
 350
 351        veth = (struct vlan_ethhdr *)(skb->data + mac_len - ETH_HLEN);
 352
 353        /* first, the ethernet type */
 354        if (likely(mac_len >= ETH_TLEN)) {
 355                /* h_vlan_encapsulated_proto should already be populated, and
 356                 * skb->data has space for h_vlan_proto
 357                 */
 358                veth->h_vlan_proto = vlan_proto;
 359        } else {
 360                /* h_vlan_encapsulated_proto should not be populated, and
 361                 * skb->data has no space for h_vlan_proto
 362                 */
 363                veth->h_vlan_encapsulated_proto = skb->protocol;
 364        }
 365
 366        /* now, the TCI */
 367        veth->h_vlan_TCI = htons(vlan_tci);
 368
 369        return 0;
 370}
 371
 372/**
 373 * __vlan_insert_tag - regular VLAN tag inserting
 374 * @skb: skbuff to tag
 375 * @vlan_proto: VLAN encapsulation protocol
 376 * @vlan_tci: VLAN TCI to insert
 377 *
 378 * Inserts the VLAN tag into @skb as part of the payload
 379 * Returns error if skb_cow_head fails.
 380 *
 381 * Does not change skb->protocol so this function can be used during receive.
 382 */
 383static inline int __vlan_insert_tag(struct sk_buff *skb,
 384                                    __be16 vlan_proto, u16 vlan_tci)
 385{
 386        return __vlan_insert_inner_tag(skb, vlan_proto, vlan_tci, ETH_HLEN);
 387}
 388
 389/**
 390 * vlan_insert_inner_tag - inner VLAN tag inserting
 391 * @skb: skbuff to tag
 392 * @vlan_proto: VLAN encapsulation protocol
 393 * @vlan_tci: VLAN TCI to insert
 394 * @mac_len: MAC header length including outer vlan headers
 395 *
 396 * Inserts the VLAN tag into @skb as part of the payload at offset mac_len
 397 * Returns a VLAN tagged skb. If a new skb is created, @skb is freed.
 398 *
 399 * Following the skb_unshare() example, in case of error, the calling function
 400 * doesn't have to worry about freeing the original skb.
 401 *
 402 * Does not change skb->protocol so this function can be used during receive.
 403 */
 404static inline struct sk_buff *vlan_insert_inner_tag(struct sk_buff *skb,
 405                                                    __be16 vlan_proto,
 406                                                    u16 vlan_tci,
 407                                                    unsigned int mac_len)
 408{
 409        int err;
 410
 411        err = __vlan_insert_inner_tag(skb, vlan_proto, vlan_tci, mac_len);
 412        if (err) {
 413                dev_kfree_skb_any(skb);
 414                return NULL;
 415        }
 416        return skb;
 417}
 418
 419/**
 420 * vlan_insert_tag - regular VLAN tag inserting
 421 * @skb: skbuff to tag
 422 * @vlan_proto: VLAN encapsulation protocol
 423 * @vlan_tci: VLAN TCI to insert
 424 *
 425 * Inserts the VLAN tag into @skb as part of the payload
 426 * Returns a VLAN tagged skb. If a new skb is created, @skb is freed.
 427 *
 428 * Following the skb_unshare() example, in case of error, the calling function
 429 * doesn't have to worry about freeing the original skb.
 430 *
 431 * Does not change skb->protocol so this function can be used during receive.
 432 */
 433static inline struct sk_buff *vlan_insert_tag(struct sk_buff *skb,
 434                                              __be16 vlan_proto, u16 vlan_tci)
 435{
 436        return vlan_insert_inner_tag(skb, vlan_proto, vlan_tci, ETH_HLEN);
 437}
 438
 439/**
 440 * vlan_insert_tag_set_proto - regular VLAN tag inserting
 441 * @skb: skbuff to tag
 442 * @vlan_proto: VLAN encapsulation protocol
 443 * @vlan_tci: VLAN TCI to insert
 444 *
 445 * Inserts the VLAN tag into @skb as part of the payload
 446 * Returns a VLAN tagged skb. If a new skb is created, @skb is freed.
 447 *
 448 * Following the skb_unshare() example, in case of error, the calling function
 449 * doesn't have to worry about freeing the original skb.
 450 */
 451static inline struct sk_buff *vlan_insert_tag_set_proto(struct sk_buff *skb,
 452                                                        __be16 vlan_proto,
 453                                                        u16 vlan_tci)
 454{
 455        skb = vlan_insert_tag(skb, vlan_proto, vlan_tci);
 456        if (skb)
 457                skb->protocol = vlan_proto;
 458        return skb;
 459}
 460
 461/**
 462 * __vlan_hwaccel_clear_tag - clear hardware accelerated VLAN info
 463 * @skb: skbuff to clear
 464 *
 465 * Clears the VLAN information from @skb
 466 */
 467static inline void __vlan_hwaccel_clear_tag(struct sk_buff *skb)
 468{
 469        skb->vlan_present = 0;
 470}
 471
 472/**
 473 * __vlan_hwaccel_copy_tag - copy hardware accelerated VLAN info from another skb
 474 * @dst: skbuff to copy to
 475 * @src: skbuff to copy from
 476 *
 477 * Copies VLAN information from @src to @dst (for branchless code)
 478 */
 479static inline void __vlan_hwaccel_copy_tag(struct sk_buff *dst, const struct sk_buff *src)
 480{
 481        dst->vlan_present = src->vlan_present;
 482        dst->vlan_proto = src->vlan_proto;
 483        dst->vlan_tci = src->vlan_tci;
 484}
 485
 486/*
 487 * __vlan_hwaccel_push_inside - pushes vlan tag to the payload
 488 * @skb: skbuff to tag
 489 *
 490 * Pushes the VLAN tag from @skb->vlan_tci inside to the payload.
 491 *
 492 * Following the skb_unshare() example, in case of error, the calling function
 493 * doesn't have to worry about freeing the original skb.
 494 */
 495static inline struct sk_buff *__vlan_hwaccel_push_inside(struct sk_buff *skb)
 496{
 497        skb = vlan_insert_tag_set_proto(skb, skb->vlan_proto,
 498                                        skb_vlan_tag_get(skb));
 499        if (likely(skb))
 500                __vlan_hwaccel_clear_tag(skb);
 501        return skb;
 502}
 503
 504/**
 505 * __vlan_hwaccel_put_tag - hardware accelerated VLAN inserting
 506 * @skb: skbuff to tag
 507 * @vlan_proto: VLAN encapsulation protocol
 508 * @vlan_tci: VLAN TCI to insert
 509 *
 510 * Puts the VLAN TCI in @skb->vlan_tci and lets the device do the rest
 511 */
 512static inline void __vlan_hwaccel_put_tag(struct sk_buff *skb,
 513                                          __be16 vlan_proto, u16 vlan_tci)
 514{
 515        skb->vlan_proto = vlan_proto;
 516        skb->vlan_tci = vlan_tci;
 517        skb->vlan_present = 1;
 518}
 519
 520/**
 521 * __vlan_get_tag - get the VLAN ID that is part of the payload
 522 * @skb: skbuff to query
 523 * @vlan_tci: buffer to store value
 524 *
 525 * Returns error if the skb is not of VLAN type
 526 */
 527static inline int __vlan_get_tag(const struct sk_buff *skb, u16 *vlan_tci)
 528{
 529        struct vlan_ethhdr *veth = (struct vlan_ethhdr *)skb->data;
 530
 531        if (!eth_type_vlan(veth->h_vlan_proto))
 532                return -EINVAL;
 533
 534        *vlan_tci = ntohs(veth->h_vlan_TCI);
 535        return 0;
 536}
 537
 538/**
 539 * __vlan_hwaccel_get_tag - get the VLAN ID that is in @skb->cb[]
 540 * @skb: skbuff to query
 541 * @vlan_tci: buffer to store value
 542 *
 543 * Returns error if @skb->vlan_tci is not set correctly
 544 */
 545static inline int __vlan_hwaccel_get_tag(const struct sk_buff *skb,
 546                                         u16 *vlan_tci)
 547{
 548        if (skb_vlan_tag_present(skb)) {
 549                *vlan_tci = skb_vlan_tag_get(skb);
 550                return 0;
 551        } else {
 552                *vlan_tci = 0;
 553                return -EINVAL;
 554        }
 555}
 556
 557/**
 558 * vlan_get_tag - get the VLAN ID from the skb
 559 * @skb: skbuff to query
 560 * @vlan_tci: buffer to store value
 561 *
 562 * Returns error if the skb is not VLAN tagged
 563 */
 564static inline int vlan_get_tag(const struct sk_buff *skb, u16 *vlan_tci)
 565{
 566        if (skb->dev->features & NETIF_F_HW_VLAN_CTAG_TX) {
 567                return __vlan_hwaccel_get_tag(skb, vlan_tci);
 568        } else {
 569                return __vlan_get_tag(skb, vlan_tci);
 570        }
 571}
 572
 573/**
 574 * vlan_get_protocol - get protocol EtherType.
 575 * @skb: skbuff to query
 576 * @type: first vlan protocol
 577 * @depth: buffer to store length of eth and vlan tags in bytes
 578 *
 579 * Returns the EtherType of the packet, regardless of whether it is
 580 * vlan encapsulated (normal or hardware accelerated) or not.
 581 */
 582static inline __be16 __vlan_get_protocol(const struct sk_buff *skb, __be16 type,
 583                                         int *depth)
 584{
 585        unsigned int vlan_depth = skb->mac_len, parse_depth = VLAN_MAX_DEPTH;
 586
 587        /* if type is 802.1Q/AD then the header should already be
 588         * present at mac_len - VLAN_HLEN (if mac_len > 0), or at
 589         * ETH_HLEN otherwise
 590         */
 591        if (eth_type_vlan(type)) {
 592                if (vlan_depth) {
 593                        if (WARN_ON(vlan_depth < VLAN_HLEN))
 594                                return 0;
 595                        vlan_depth -= VLAN_HLEN;
 596                } else {
 597                        vlan_depth = ETH_HLEN;
 598                }
 599                do {
 600                        struct vlan_hdr vhdr, *vh;
 601
 602                        vh = skb_header_pointer(skb, vlan_depth, sizeof(vhdr), &vhdr);
 603                        if (unlikely(!vh || !--parse_depth))
 604                                return 0;
 605
 606                        type = vh->h_vlan_encapsulated_proto;
 607                        vlan_depth += VLAN_HLEN;
 608                } while (eth_type_vlan(type));
 609        }
 610
 611        if (depth)
 612                *depth = vlan_depth;
 613
 614        return type;
 615}
 616
 617/**
 618 * vlan_get_protocol - get protocol EtherType.
 619 * @skb: skbuff to query
 620 *
 621 * Returns the EtherType of the packet, regardless of whether it is
 622 * vlan encapsulated (normal or hardware accelerated) or not.
 623 */
 624static inline __be16 vlan_get_protocol(const struct sk_buff *skb)
 625{
 626        return __vlan_get_protocol(skb, skb->protocol, NULL);
 627}
 628
 629/* A getter for the SKB protocol field which will handle VLAN tags consistently
 630 * whether VLAN acceleration is enabled or not.
 631 */
 632static inline __be16 skb_protocol(const struct sk_buff *skb, bool skip_vlan)
 633{
 634        if (!skip_vlan)
 635                /* VLAN acceleration strips the VLAN header from the skb and
 636                 * moves it to skb->vlan_proto
 637                 */
 638                return skb_vlan_tag_present(skb) ? skb->vlan_proto : skb->protocol;
 639
 640        return vlan_get_protocol(skb);
 641}
 642
 643static inline void vlan_set_encap_proto(struct sk_buff *skb,
 644                                        struct vlan_hdr *vhdr)
 645{
 646        __be16 proto;
 647        unsigned short *rawp;
 648
 649        /*
 650         * Was a VLAN packet, grab the encapsulated protocol, which the layer
 651         * three protocols care about.
 652         */
 653
 654        proto = vhdr->h_vlan_encapsulated_proto;
 655        if (eth_proto_is_802_3(proto)) {
 656                skb->protocol = proto;
 657                return;
 658        }
 659
 660        rawp = (unsigned short *)(vhdr + 1);
 661        if (*rawp == 0xFFFF)
 662                /*
 663                 * This is a magic hack to spot IPX packets. Older Novell
 664                 * breaks the protocol design and runs IPX over 802.3 without
 665                 * an 802.2 LLC layer. We look for FFFF which isn't a used
 666                 * 802.2 SSAP/DSAP. This won't work for fault tolerant netware
 667                 * but does for the rest.
 668                 */
 669                skb->protocol = htons(ETH_P_802_3);
 670        else
 671                /*
 672                 * Real 802.2 LLC
 673                 */
 674                skb->protocol = htons(ETH_P_802_2);
 675}
 676
 677/**
 678 * skb_vlan_tagged - check if skb is vlan tagged.
 679 * @skb: skbuff to query
 680 *
 681 * Returns true if the skb is tagged, regardless of whether it is hardware
 682 * accelerated or not.
 683 */
 684static inline bool skb_vlan_tagged(const struct sk_buff *skb)
 685{
 686        if (!skb_vlan_tag_present(skb) &&
 687            likely(!eth_type_vlan(skb->protocol)))
 688                return false;
 689
 690        return true;
 691}
 692
 693/**
 694 * skb_vlan_tagged_multi - check if skb is vlan tagged with multiple headers.
 695 * @skb: skbuff to query
 696 *
 697 * Returns true if the skb is tagged with multiple vlan headers, regardless
 698 * of whether it is hardware accelerated or not.
 699 */
 700static inline bool skb_vlan_tagged_multi(struct sk_buff *skb)
 701{
 702        __be16 protocol = skb->protocol;
 703
 704        if (!skb_vlan_tag_present(skb)) {
 705                struct vlan_ethhdr *veh;
 706
 707                if (likely(!eth_type_vlan(protocol)))
 708                        return false;
 709
 710                if (unlikely(!pskb_may_pull(skb, VLAN_ETH_HLEN)))
 711                        return false;
 712
 713                veh = (struct vlan_ethhdr *)skb->data;
 714                protocol = veh->h_vlan_encapsulated_proto;
 715        }
 716
 717        if (!eth_type_vlan(protocol))
 718                return false;
 719
 720        return true;
 721}
 722
 723/**
 724 * vlan_features_check - drop unsafe features for skb with multiple tags.
 725 * @skb: skbuff to query
 726 * @features: features to be checked
 727 *
 728 * Returns features without unsafe ones if the skb has multiple tags.
 729 */
 730static inline netdev_features_t vlan_features_check(struct sk_buff *skb,
 731                                                    netdev_features_t features)
 732{
 733        if (skb_vlan_tagged_multi(skb)) {
 734                /* In the case of multi-tagged packets, use a direct mask
 735                 * instead of using netdev_interesect_features(), to make
 736                 * sure that only devices supporting NETIF_F_HW_CSUM will
 737                 * have checksum offloading support.
 738                 */
 739                features &= NETIF_F_SG | NETIF_F_HIGHDMA | NETIF_F_HW_CSUM |
 740                            NETIF_F_FRAGLIST | NETIF_F_HW_VLAN_CTAG_TX |
 741                            NETIF_F_HW_VLAN_STAG_TX;
 742        }
 743
 744        return features;
 745}
 746
 747/**
 748 * compare_vlan_header - Compare two vlan headers
 749 * @h1: Pointer to vlan header
 750 * @h2: Pointer to vlan header
 751 *
 752 * Compare two vlan headers, returns 0 if equal.
 753 *
 754 * Please note that alignment of h1 & h2 are only guaranteed to be 16 bits.
 755 */
 756static inline unsigned long compare_vlan_header(const struct vlan_hdr *h1,
 757                                                const struct vlan_hdr *h2)
 758{
 759#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
 760        return *(u32 *)h1 ^ *(u32 *)h2;
 761#else
 762        return ((__force u32)h1->h_vlan_TCI ^ (__force u32)h2->h_vlan_TCI) |
 763               ((__force u32)h1->h_vlan_encapsulated_proto ^
 764                (__force u32)h2->h_vlan_encapsulated_proto);
 765#endif
 766}
 767#endif /* !(_LINUX_IF_VLAN_H_) */
 768