include/linux/if_vlan.h

   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  */
  38 struct 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
  48  *      @h_vlan_TCI: priority and VLAN ID
  49  *      @h_vlan_encapsulated_proto: packet type ID or len
  50  */
  51 struct 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
  61 static 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 */
  74 extern void vlan_ioctl_set(int (*hook)(struct net *, void __user *));
  75
  76 static 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_tag_get(__skb)          ((__skb)->vlan_tci & ~VLAN_TAG_PRESENT)
  83 #define vlan_tx_tag_get_id(__skb)       ((__skb)->vlan_tci & VLAN_VID_MASK)
  84
  85 #if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
  86
  87 extern struct net_device *__vlan_find_dev_deep(struct net_device *real_dev,
  88                                                __be16 vlan_proto, u16 vlan_id);
  89 extern struct net_device *vlan_dev_real_dev(const struct net_device *dev);
  90 extern u16 vlan_dev_vlan_id(const struct net_device *dev);
  91
  92 extern bool vlan_do_receive(struct sk_buff **skb);
  93 extern struct sk_buff *vlan_untag(struct sk_buff *skb);
  94
  95 extern int vlan_vid_add(struct net_device *dev, __be16 proto, u16 vid);
  96 extern void vlan_vid_del(struct net_device *dev, __be16 proto, u16 vid);
  97
  98 extern int vlan_vids_add_by_dev(struct net_device *dev,
  99                                 const struct net_device *by_dev);
 100 extern void vlan_vids_del_by_dev(struct net_device *dev,
 101                                  const struct net_device *by_dev);
 102
 103 extern bool vlan_uses_dev(const struct net_device *dev);
 104 #else
 105 static inline struct net_device *
 106 __vlan_find_dev_deep(struct net_device *real_dev,
 107                      __be16 vlan_proto, u16 vlan_id)
 108 {
 109         return NULL;
 110 }
 111
 112 static inline struct net_device *vlan_dev_real_dev(const struct net_device *dev)
 113 {
 114         BUG();
 115         return NULL;
 116 }
 117
 118 static inline u16 vlan_dev_vlan_id(const struct net_device *dev)
 119 {
 120         BUG();
 121         return 0;
 122 }
 123
 124 static inline bool vlan_do_receive(struct sk_buff **skb)
 125 {
 126         return false;
 127 }
 128
 129 static inline struct sk_buff *vlan_untag(struct sk_buff *skb)
 130 {
 131         return skb;
 132 }
 133
 134 static inline int vlan_vid_add(struct net_device *dev, __be16 proto, u16 vid)
 135 {
 136         return 0;
 137 }
 138
 139 static inline void vlan_vid_del(struct net_device *dev, __be16 proto, u16 vid)
 140 {
 141 }
 142
 143 static inline int vlan_vids_add_by_dev(struct net_device *dev,
 144                                        const struct net_device *by_dev)
 145 {
 146         return 0;
 147 }
 148
 149 static inline void vlan_vids_del_by_dev(struct net_device *dev,
 150                                         const struct net_device *by_dev)
 151 {
 152 }
 153
 154 static inline bool vlan_uses_dev(const struct net_device *dev)
 155 {
 156         return false;
 157 }
 158 #endif
 159
 160 static inline bool vlan_hw_offload_capable(netdev_features_t features,
 161                                            __be16 proto)
 162 {
 163         if (proto == htons(ETH_P_8021Q) && features & NETIF_F_HW_VLAN_CTAG_TX)
 164                 return true;
 165         if (proto == htons(ETH_P_8021AD) && features & NETIF_F_HW_VLAN_STAG_TX)
 166                 return true;
 167         return false;
 168 }
 169
 170 /**
 171  * vlan_insert_tag - regular VLAN tag inserting
 172  * @skb: skbuff to tag
 173  * @vlan_proto: VLAN encapsulation protocol
 174  * @vlan_tci: VLAN TCI to insert
 175  *
 176  * Inserts the VLAN tag into @skb as part of the payload
 177  * Returns a VLAN tagged skb. If a new skb is created, @skb is freed.
 178  *
 179  * Following the skb_unshare() example, in case of error, the calling function
 180  * doesn't have to worry about freeing the original skb.
 181  *
 182  * Does not change skb->protocol so this function can be used during receive.
 183  */
 184 static inline struct sk_buff *vlan_insert_tag(struct sk_buff *skb,
 185                                               __be16 vlan_proto, u16 vlan_tci)
 186 {
 187         struct vlan_ethhdr *veth;
 188
 189         if (skb_cow_head(skb, VLAN_HLEN) < 0) {
 190                 kfree_skb(skb);
 191                 return NULL;
 192         }
 193         veth = (struct vlan_ethhdr *)skb_push(skb, VLAN_HLEN);
 194
 195         /* Move the mac addresses to the beginning of the new header. */
 196         memmove(skb->data, skb->data + VLAN_HLEN, 2 * ETH_ALEN);
 197         skb->mac_header -= VLAN_HLEN;
 198
 199         /* first, the ethernet type */
 200         veth->h_vlan_proto = vlan_proto;
 201
 202         /* now, the TCI */
 203         veth->h_vlan_TCI = htons(vlan_tci);
 204
 205         return skb;
 206 }
 207
 208 /**
 209  * __vlan_put_tag - regular VLAN tag inserting
 210  * @skb: skbuff to tag
 211  * @vlan_tci: VLAN TCI to insert
 212  *
 213  * Inserts the VLAN tag into @skb as part of the payload
 214  * Returns a VLAN tagged skb. If a new skb is created, @skb is freed.
 215  *
 216  * Following the skb_unshare() example, in case of error, the calling function
 217  * doesn't have to worry about freeing the original skb.
 218  */
 219 static inline struct sk_buff *__vlan_put_tag(struct sk_buff *skb,
 220                                              __be16 vlan_proto, u16 vlan_tci)
 221 {
 222         skb = vlan_insert_tag(skb, vlan_proto, vlan_tci);
 223         if (skb)
 224                 skb->protocol = vlan_proto;
 225         return skb;
 226 }
 227
 228 /**
 229  * __vlan_hwaccel_put_tag - hardware accelerated VLAN inserting
 230  * @skb: skbuff to tag
 231  * @vlan_proto: VLAN encapsulation protocol
 232  * @vlan_tci: VLAN TCI to insert
 233  *
 234  * Puts the VLAN TCI in @skb->vlan_tci and lets the device do the rest
 235  */
 236 static inline struct sk_buff *__vlan_hwaccel_put_tag(struct sk_buff *skb,
 237                                                      __be16 vlan_proto,
 238                                                      u16 vlan_tci)
 239 {
 240         skb->vlan_proto = vlan_proto;
 241         skb->vlan_tci = VLAN_TAG_PRESENT | vlan_tci;
 242         return skb;
 243 }
 244
 245 /**
 246  * vlan_put_tag - inserts VLAN tag according to device features
 247  * @skb: skbuff to tag
 248  * @vlan_tci: VLAN TCI to insert
 249  *
 250  * Assumes skb->dev is the target that will xmit this frame.
 251  * Returns a VLAN tagged skb.
 252  */
 253 static inline struct sk_buff *vlan_put_tag(struct sk_buff *skb,
 254                                            __be16 vlan_proto, u16 vlan_tci)
 255 {
 256         if (vlan_hw_offload_capable(skb->dev->features, vlan_proto)) {
 257                 return __vlan_hwaccel_put_tag(skb, vlan_proto, vlan_tci);
 258         } else {
 259                 return __vlan_put_tag(skb, vlan_proto, vlan_tci);
 260         }
 261 }
 262
 263 /**
 264  * __vlan_get_tag - get the VLAN ID that is part of the payload
 265  * @skb: skbuff to query
 266  * @vlan_tci: buffer to store vlaue
 267  *
 268  * Returns error if the skb is not of VLAN type
 269  */
 270 static inline int __vlan_get_tag(const struct sk_buff *skb, u16 *vlan_tci)
 271 {
 272         struct vlan_ethhdr *veth = (struct vlan_ethhdr *)skb->data;
 273
 274         if (veth->h_vlan_proto != htons(ETH_P_8021Q) &&
 275             veth->h_vlan_proto != htons(ETH_P_8021AD))
 276                 return -EINVAL;
 277
 278         *vlan_tci = ntohs(veth->h_vlan_TCI);
 279         return 0;
 280 }
 281
 282 /**
 283  * __vlan_hwaccel_get_tag - get the VLAN ID that is in @skb->cb[]
 284  * @skb: skbuff to query
 285  * @vlan_tci: buffer to store vlaue
 286  *
 287  * Returns error if @skb->vlan_tci is not set correctly
 288  */
 289 static inline int __vlan_hwaccel_get_tag(const struct sk_buff *skb,
 290                                          u16 *vlan_tci)
 291 {
 292         if (vlan_tx_tag_present(skb)) {
 293                 *vlan_tci = vlan_tx_tag_get(skb);
 294                 return 0;
 295         } else {
 296                 *vlan_tci = 0;
 297                 return -EINVAL;
 298         }
 299 }
 300
 301 #define HAVE_VLAN_GET_TAG
 302
 303 /**
 304  * vlan_get_tag - get the VLAN ID from the skb
 305  * @skb: skbuff to query
 306  * @vlan_tci: buffer to store vlaue
 307  *
 308  * Returns error if the skb is not VLAN tagged
 309  */
 310 static inline int vlan_get_tag(const struct sk_buff *skb, u16 *vlan_tci)
 311 {
 312         if (skb->dev->features & NETIF_F_HW_VLAN_CTAG_TX) {
 313                 return __vlan_hwaccel_get_tag(skb, vlan_tci);
 314         } else {
 315                 return __vlan_get_tag(skb, vlan_tci);
 316         }
 317 }
 318
 319 /**
 320  * vlan_get_protocol - get protocol EtherType.
 321  * @skb: skbuff to query
 322  *
 323  * Returns the EtherType of the packet, regardless of whether it is
 324  * vlan encapsulated (normal or hardware accelerated) or not.
 325  */
 326 static inline __be16 vlan_get_protocol(const struct sk_buff *skb)
 327 {
 328         __be16 protocol = 0;
 329
 330         if (vlan_tx_tag_present(skb) ||
 331              skb->protocol != cpu_to_be16(ETH_P_8021Q))
 332                 protocol = skb->protocol;
 333         else {
 334                 __be16 proto, *protop;
 335                 protop = skb_header_pointer(skb, offsetof(struct vlan_ethhdr,
 336                                                 h_vlan_encapsulated_proto),
 337                                                 sizeof(proto), &proto);
 338                 if (likely(protop))
 339                         protocol = *protop;
 340         }
 341
 342         return protocol;
 343 }
 344
 345 static inline void vlan_set_encap_proto(struct sk_buff *skb,
 346                                         struct vlan_hdr *vhdr)
 347 {
 348         __be16 proto;
 349         unsigned short *rawp;
 350
 351         /*
 352          * Was a VLAN packet, grab the encapsulated protocol, which the layer
 353          * three protocols care about.
 354          */
 355
 356         proto = vhdr->h_vlan_encapsulated_proto;
 357         if (ntohs(proto) >= ETH_P_802_3_MIN) {
 358                 skb->protocol = proto;
 359                 return;
 360         }
 361
 362         rawp = (unsigned short *)(vhdr + 1);
 363         if (*rawp == 0xFFFF)
 364                 /*
 365                  * This is a magic hack to spot IPX packets. Older Novell
 366                  * breaks the protocol design and runs IPX over 802.3 without
 367                  * an 802.2 LLC layer. We look for FFFF which isn't a used
 368                  * 802.2 SSAP/DSAP. This won't work for fault tolerant netware
 369                  * but does for the rest.
 370                  */
 371                 skb->protocol = htons(ETH_P_802_3);
 372         else
 373                 /*
 374                  * Real 802.2 LLC
 375                  */
 376                 skb->protocol = htons(ETH_P_802_2);
 377 }
 378 #endif /* !(_LINUX_IF_VLAN_H_) */