linux/include/linux/if_vlan.h
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   1/*
   2 * VLAN         An implementation of 802.1Q VLAN tagging.
   3 *
   4 * Authors:     Ben Greear <greearb@candelatech.com>
   5 *
   6 *              This program is free software; you can redistribute it and/or
   7 *              modify it under the terms of the GNU General Public License
   8 *              as published by the Free Software Foundation; either version
   9 *              2 of the License, or (at your option) any later version.
  10 *
  11 */
  12#ifndef _LINUX_IF_VLAN_H_
  13#define _LINUX_IF_VLAN_H_
  14
  15#include <linux/netdevice.h>
  16#include <linux/etherdevice.h>
  17#include <linux/rtnetlink.h>
  18#include <linux/bug.h>
  19#include <uapi/linux/if_vlan.h>
  20
  21#define VLAN_HLEN       4               /* The additional bytes required by VLAN
  22                                         * (in addition to the Ethernet header)
  23                                         */
  24#define VLAN_ETH_HLEN   18              /* Total octets in header.       */
  25#define VLAN_ETH_ZLEN   64              /* Min. octets in frame sans FCS */
  26
  27/*
  28 * According to 802.3ac, the packet can be 4 bytes longer. --Klika Jan
  29 */
  30#define VLAN_ETH_DATA_LEN       1500    /* Max. octets in payload        */
  31#define VLAN_ETH_FRAME_LEN      1518    /* Max. octets in frame sans FCS */
  32
  33/*
  34 *      struct vlan_hdr - vlan header
  35 *      @h_vlan_TCI: priority and VLAN ID
  36 *      @h_vlan_encapsulated_proto: packet type ID or len
  37 */
  38struct vlan_hdr {
  39        __be16  h_vlan_TCI;
  40        __be16  h_vlan_encapsulated_proto;
  41};
  42
  43/**
  44 *      struct vlan_ethhdr - vlan ethernet header (ethhdr + vlan_hdr)
  45 *      @h_dest: destination ethernet address
  46 *      @h_source: source ethernet address
  47 *      @h_vlan_proto: ethernet protocol (always 0x8100)
  48 *      @h_vlan_TCI: priority and VLAN ID
  49 *      @h_vlan_encapsulated_proto: packet type ID or len
  50 */
  51struct vlan_ethhdr {
  52        unsigned char   h_dest[ETH_ALEN];
  53        unsigned char   h_source[ETH_ALEN];
  54        __be16          h_vlan_proto;
  55        __be16          h_vlan_TCI;
  56        __be16          h_vlan_encapsulated_proto;
  57};
  58
  59#include <linux/skbuff.h>
  60
  61static inline struct vlan_ethhdr *vlan_eth_hdr(const struct sk_buff *skb)
  62{
  63        return (struct vlan_ethhdr *)skb_mac_header(skb);
  64}
  65
  66#define VLAN_PRIO_MASK          0xe000 /* Priority Code Point */
  67#define VLAN_PRIO_SHIFT         13
  68#define VLAN_CFI_MASK           0x1000 /* Canonical Format Indicator */
  69#define VLAN_TAG_PRESENT        VLAN_CFI_MASK
  70#define VLAN_VID_MASK           0x0fff /* VLAN Identifier */
  71#define VLAN_N_VID              4096
  72
  73/* found in socket.c */
  74extern void vlan_ioctl_set(int (*hook)(struct net *, void __user *));
  75
  76static inline int is_vlan_dev(struct net_device *dev)
  77{
  78        return dev->priv_flags & IFF_802_1Q_VLAN;
  79}
  80
  81#define vlan_tx_tag_present(__skb)      ((__skb)->vlan_tci & VLAN_TAG_PRESENT)
  82#define vlan_tx_nonzero_tag_present(__skb) \
  83        (vlan_tx_tag_present(__skb) && ((__skb)->vlan_tci & VLAN_VID_MASK))
  84#define vlan_tx_tag_get(__skb)          ((__skb)->vlan_tci & ~VLAN_TAG_PRESENT)
  85
  86#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
  87
  88extern struct net_device *__vlan_find_dev_deep(struct net_device *real_dev,
  89                                               u16 vlan_id);
  90extern struct net_device *vlan_dev_real_dev(const struct net_device *dev);
  91extern u16 vlan_dev_vlan_id(const struct net_device *dev);
  92
  93extern bool vlan_do_receive(struct sk_buff **skb);
  94extern struct sk_buff *vlan_untag(struct sk_buff *skb);
  95
  96extern int vlan_vid_add(struct net_device *dev, unsigned short vid);
  97extern void vlan_vid_del(struct net_device *dev, unsigned short vid);
  98
  99extern int vlan_vids_add_by_dev(struct net_device *dev,
 100                                const struct net_device *by_dev);
 101extern void vlan_vids_del_by_dev(struct net_device *dev,
 102                                 const struct net_device *by_dev);
 103
 104extern bool vlan_uses_dev(const struct net_device *dev);
 105#else
 106static inline struct net_device *
 107__vlan_find_dev_deep(struct net_device *real_dev, u16 vlan_id)
 108{
 109        return NULL;
 110}
 111
 112static inline struct net_device *vlan_dev_real_dev(const struct net_device *dev)
 113{
 114        BUG();
 115        return NULL;
 116}
 117
 118static inline u16 vlan_dev_vlan_id(const struct net_device *dev)
 119{
 120        BUG();
 121        return 0;
 122}
 123
 124static inline bool vlan_do_receive(struct sk_buff **skb)
 125{
 126        return false;
 127}
 128
 129static inline struct sk_buff *vlan_untag(struct sk_buff *skb)
 130{
 131        return skb;
 132}
 133
 134static inline int vlan_vid_add(struct net_device *dev, unsigned short vid)
 135{
 136        return 0;
 137}
 138
 139static inline void vlan_vid_del(struct net_device *dev, unsigned short vid)
 140{
 141}
 142
 143static inline int vlan_vids_add_by_dev(struct net_device *dev,
 144                                       const struct net_device *by_dev)
 145{
 146        return 0;
 147}
 148
 149static inline void vlan_vids_del_by_dev(struct net_device *dev,
 150                                        const struct net_device *by_dev)
 151{
 152}
 153
 154static inline bool vlan_uses_dev(const struct net_device *dev)
 155{
 156        return false;
 157}
 158#endif
 159
 160/**
 161 * vlan_insert_tag - regular VLAN tag inserting
 162 * @skb: skbuff to tag
 163 * @vlan_tci: VLAN TCI to insert
 164 *
 165 * Inserts the VLAN tag into @skb as part of the payload
 166 * Returns a VLAN tagged skb. If a new skb is created, @skb is freed.
 167 *
 168 * Following the skb_unshare() example, in case of error, the calling function
 169 * doesn't have to worry about freeing the original skb.
 170 *
 171 * Does not change skb->protocol so this function can be used during receive.
 172 */
 173static inline struct sk_buff *vlan_insert_tag(struct sk_buff *skb, u16 vlan_tci)
 174{
 175        struct vlan_ethhdr *veth;
 176
 177        if (skb_cow_head(skb, VLAN_HLEN) < 0) {
 178                kfree_skb(skb);
 179                return NULL;
 180        }
 181        veth = (struct vlan_ethhdr *)skb_push(skb, VLAN_HLEN);
 182
 183        /* Move the mac addresses to the beginning of the new header. */
 184        memmove(skb->data, skb->data + VLAN_HLEN, 2 * ETH_ALEN);
 185        skb->mac_header -= VLAN_HLEN;
 186
 187        /* first, the ethernet type */
 188        veth->h_vlan_proto = htons(ETH_P_8021Q);
 189
 190        /* now, the TCI */
 191        veth->h_vlan_TCI = htons(vlan_tci);
 192
 193        return skb;
 194}
 195
 196/**
 197 * __vlan_put_tag - regular VLAN tag inserting
 198 * @skb: skbuff to tag
 199 * @vlan_tci: VLAN TCI to insert
 200 *
 201 * Inserts the VLAN tag into @skb as part of the payload
 202 * Returns a VLAN tagged skb. If a new skb is created, @skb is freed.
 203 *
 204 * Following the skb_unshare() example, in case of error, the calling function
 205 * doesn't have to worry about freeing the original skb.
 206 */
 207static inline struct sk_buff *__vlan_put_tag(struct sk_buff *skb, u16 vlan_tci)
 208{
 209        skb = vlan_insert_tag(skb, vlan_tci);
 210        if (skb)
 211                skb->protocol = htons(ETH_P_8021Q);
 212        return skb;
 213}
 214
 215/**
 216 * __vlan_hwaccel_put_tag - hardware accelerated VLAN inserting
 217 * @skb: skbuff to tag
 218 * @vlan_tci: VLAN TCI to insert
 219 *
 220 * Puts the VLAN TCI in @skb->vlan_tci and lets the device do the rest
 221 */
 222static inline struct sk_buff *__vlan_hwaccel_put_tag(struct sk_buff *skb,
 223                                                     u16 vlan_tci)
 224{
 225        skb->vlan_tci = VLAN_TAG_PRESENT | vlan_tci;
 226        return skb;
 227}
 228
 229#define HAVE_VLAN_PUT_TAG
 230
 231/**
 232 * vlan_put_tag - inserts VLAN tag according to device features
 233 * @skb: skbuff to tag
 234 * @vlan_tci: VLAN TCI to insert
 235 *
 236 * Assumes skb->dev is the target that will xmit this frame.
 237 * Returns a VLAN tagged skb.
 238 */
 239static inline struct sk_buff *vlan_put_tag(struct sk_buff *skb, u16 vlan_tci)
 240{
 241        if (skb->dev->features & NETIF_F_HW_VLAN_TX) {
 242                return __vlan_hwaccel_put_tag(skb, vlan_tci);
 243        } else {
 244                return __vlan_put_tag(skb, vlan_tci);
 245        }
 246}
 247
 248/**
 249 * __vlan_get_tag - get the VLAN ID that is part of the payload
 250 * @skb: skbuff to query
 251 * @vlan_tci: buffer to store vlaue
 252 *
 253 * Returns error if the skb is not of VLAN type
 254 */
 255static inline int __vlan_get_tag(const struct sk_buff *skb, u16 *vlan_tci)
 256{
 257        struct vlan_ethhdr *veth = (struct vlan_ethhdr *)skb->data;
 258
 259        if (veth->h_vlan_proto != htons(ETH_P_8021Q)) {
 260                return -EINVAL;
 261        }
 262
 263        *vlan_tci = ntohs(veth->h_vlan_TCI);
 264        return 0;
 265}
 266
 267/**
 268 * __vlan_hwaccel_get_tag - get the VLAN ID that is in @skb->cb[]
 269 * @skb: skbuff to query
 270 * @vlan_tci: buffer to store vlaue
 271 *
 272 * Returns error if @skb->vlan_tci is not set correctly
 273 */
 274static inline int __vlan_hwaccel_get_tag(const struct sk_buff *skb,
 275                                         u16 *vlan_tci)
 276{
 277        if (vlan_tx_tag_present(skb)) {
 278                *vlan_tci = vlan_tx_tag_get(skb);
 279                return 0;
 280        } else {
 281                *vlan_tci = 0;
 282                return -EINVAL;
 283        }
 284}
 285
 286#define HAVE_VLAN_GET_TAG
 287
 288/**
 289 * vlan_get_tag - get the VLAN ID from the skb
 290 * @skb: skbuff to query
 291 * @vlan_tci: buffer to store vlaue
 292 *
 293 * Returns error if the skb is not VLAN tagged
 294 */
 295static inline int vlan_get_tag(const struct sk_buff *skb, u16 *vlan_tci)
 296{
 297        if (skb->dev->features & NETIF_F_HW_VLAN_TX) {
 298                return __vlan_hwaccel_get_tag(skb, vlan_tci);
 299        } else {
 300                return __vlan_get_tag(skb, vlan_tci);
 301        }
 302}
 303
 304/**
 305 * vlan_get_protocol - get protocol EtherType.
 306 * @skb: skbuff to query
 307 *
 308 * Returns the EtherType of the packet, regardless of whether it is
 309 * vlan encapsulated (normal or hardware accelerated) or not.
 310 */
 311static inline __be16 vlan_get_protocol(const struct sk_buff *skb)
 312{
 313        __be16 protocol = 0;
 314
 315        if (vlan_tx_tag_present(skb) ||
 316             skb->protocol != cpu_to_be16(ETH_P_8021Q))
 317                protocol = skb->protocol;
 318        else {
 319                __be16 proto, *protop;
 320                protop = skb_header_pointer(skb, offsetof(struct vlan_ethhdr,
 321                                                h_vlan_encapsulated_proto),
 322                                                sizeof(proto), &proto);
 323                if (likely(protop))
 324                        protocol = *protop;
 325        }
 326
 327        return protocol;
 328}
 329
 330static inline void vlan_set_encap_proto(struct sk_buff *skb,
 331                                        struct vlan_hdr *vhdr)
 332{
 333        __be16 proto;
 334        unsigned char *rawp;
 335
 336        /*
 337         * Was a VLAN packet, grab the encapsulated protocol, which the layer
 338         * three protocols care about.
 339         */
 340
 341        proto = vhdr->h_vlan_encapsulated_proto;
 342        if (ntohs(proto) >= 1536) {
 343                skb->protocol = proto;
 344                return;
 345        }
 346
 347        rawp = skb->data;
 348        if (*(unsigned short *) rawp == 0xFFFF)
 349                /*
 350                 * This is a magic hack to spot IPX packets. Older Novell
 351                 * breaks the protocol design and runs IPX over 802.3 without
 352                 * an 802.2 LLC layer. We look for FFFF which isn't a used
 353                 * 802.2 SSAP/DSAP. This won't work for fault tolerant netware
 354                 * but does for the rest.
 355                 */
 356                skb->protocol = htons(ETH_P_802_3);
 357        else
 358                /*
 359                 * Real 802.2 LLC
 360                 */
 361                skb->protocol = htons(ETH_P_802_2);
 362}
 363#endif /* !(_LINUX_IF_VLAN_H_) */
 364
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