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