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 (always 0x8100)
  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_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
  88 extern struct net_device *__vlan_find_dev_deep(struct net_device *real_dev,
  89                                                u16 vlan_id);
  90 extern struct net_device *vlan_dev_real_dev(const struct net_device *dev);
  91 extern u16 vlan_dev_vlan_id(const struct net_device *dev);
  92
  93 extern bool vlan_do_receive(struct sk_buff **skb);
  94 extern struct sk_buff *vlan_untag(struct sk_buff *skb);
  95
  96 extern int vlan_vid_add(struct net_device *dev, unsigned short vid);
  97 extern void vlan_vid_del(struct net_device *dev, unsigned short vid);
  98
  99 extern int vlan_vids_add_by_dev(struct net_device *dev,
 100                                 const struct net_device *by_dev);
 101 extern void vlan_vids_del_by_dev(struct net_device *dev,
 102                                  const struct net_device *by_dev);
 103
 104 extern bool vlan_uses_dev(const struct net_device *dev);
 105 #else
 106 static inline struct net_device *
 107 __vlan_find_dev_deep(struct net_device *real_dev, 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, unsigned short vid)
 135 {
 136         return 0;
 137 }
 138
 139 static inline void vlan_vid_del(struct net_device *dev, unsigned short 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 /**
 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  */
 173 static 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  */
 207 static 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  */
 222 static 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  */
 239 static 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  */
 255 static 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  */
 274 static 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  */
 295 static 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  */
 311 static 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
 330 static inline void vlan_set_encap_proto(struct sk_buff *skb,
 331                                         struct vlan_hdr *vhdr)
 332 {
 333         __be16 proto;
 334         unsigned short *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 = (unsigned short *)(vhdr + 1);
 348         if (*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_) */