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
  13 #ifndef _LINUX_IF_VLAN_H_
  14 #define _LINUX_IF_VLAN_H_
  15
  16 #ifdef __KERNEL__
  17
  18 /* externally defined structs */
  19 struct vlan_group;
  20 struct net_device;
  21 struct packet_type;
  22 struct vlan_collection;
  23 struct vlan_dev_info;
  24 struct hlist_node;
  25
  26 #include <linux/proc_fs.h> /* for proc_dir_entry */
  27 #include <linux/netdevice.h>
  28
  29 #define VLAN_HLEN       4               /* The additional bytes (on top of the Ethernet header)
  30                                          * that VLAN requires.
  31                                          */
  32 #define VLAN_ETH_ALEN   6               /* Octets in one ethernet addr   */
  33 #define VLAN_ETH_HLEN   18              /* Total octets in header.       */
  34 #define VLAN_ETH_ZLEN   64              /* Min. octets in frame sans FCS */
  35
  36 /*
  37  * According to 802.3ac, the packet can be 4 bytes longer. --Klika Jan
  38  */
  39 #define VLAN_ETH_DATA_LEN       1500    /* Max. octets in payload        */
  40 #define VLAN_ETH_FRAME_LEN      1518    /* Max. octets in frame sans FCS */
  41
  42 struct vlan_ethhdr {
  43    unsigned char        h_dest[ETH_ALEN];          /* destination eth addr      */
  44    unsigned char        h_source[ETH_ALEN];        /* source ether addr */
  45    unsigned short       h_vlan_proto;              /* Should always be 0x8100 */
  46    unsigned short       h_vlan_TCI;                /* Encapsulates priority and VLAN ID */
  47    unsigned short       h_vlan_encapsulated_proto; /* packet type ID field (or len) */
  48 };
  49
  50 #include <linux/skbuff.h>
  51
  52 static inline struct vlan_ethhdr *vlan_eth_hdr(const struct sk_buff *skb)
  53 {
  54         return (struct vlan_ethhdr *)skb->mac.raw;
  55 }
  56
  57 struct vlan_hdr {
  58    unsigned short       h_vlan_TCI;                /* Encapsulates priority and VLAN ID */
  59    unsigned short       h_vlan_encapsulated_proto; /* packet type ID field (or len) */
  60 };
  61
  62 #define VLAN_VID_MASK   0xfff
  63
  64 /* found in socket.c */
  65 extern void vlan_ioctl_set(int (*hook)(void __user *));
  66
  67 #define VLAN_NAME "vlan"
  68
  69 /* if this changes, algorithm will have to be reworked because this
  70  * depends on completely exhausting the VLAN identifier space.  Thus
  71  * it gives constant time look-up, but in many cases it wastes memory.
  72  */
  73 #define VLAN_GROUP_ARRAY_LEN 4096
  74
  75 struct vlan_group {
  76         int real_dev_ifindex; /* The ifindex of the ethernet(like) device the vlan is attached to. */
  77         struct hlist_node       hlist;  /* linked list */
  78         struct net_device *vlan_devices[VLAN_GROUP_ARRAY_LEN];
  79         struct rcu_head         rcu;
  80 };
  81
  82 struct vlan_priority_tci_mapping {
  83         unsigned long priority;
  84         unsigned short vlan_qos; /* This should be shifted when first set, so we only do it
  85                                   * at provisioning time.
  86                                   * ((skb->priority << 13) & 0xE000)
  87                                   */
  88         struct vlan_priority_tci_mapping *next;
  89 };
  90
  91 /* Holds information that makes sense if this device is a VLAN device. */
  92 struct vlan_dev_info {
  93         /** This will be the mapping that correlates skb->priority to
  94          * 3 bits of VLAN QOS tags...
  95          */
  96         unsigned long ingress_priority_map[8];
  97         struct vlan_priority_tci_mapping *egress_priority_map[16]; /* hash table */
  98
  99         unsigned short vlan_id;        /*  The VLAN Identifier for this interface. */
 100         unsigned short flags;          /* (1 << 0) re_order_header   This option will cause the
 101                                         *   VLAN code to move around the ethernet header on
 102                                         *   ingress to make the skb look **exactly** like it
 103                                         *   came in from an ethernet port.  This destroys some of
 104                                         *   the VLAN information in the skb, but it fixes programs
 105                                         *   like DHCP that use packet-filtering and don't understand
 106                                         *   802.1Q
 107                                         */
 108         struct dev_mc_list *old_mc_list;  /* old multi-cast list for the VLAN interface..
 109                                            * we save this so we can tell what changes were
 110                                            * made, in order to feed the right changes down
 111                                            * to the real hardware...
 112                                            */
 113         int old_allmulti;               /* similar to above. */
 114         int old_promiscuity;            /* similar to above. */
 115         struct net_device *real_dev;    /* the underlying device/interface */
 116         struct proc_dir_entry *dent;    /* Holds the proc data */
 117         unsigned long cnt_inc_headroom_on_tx; /* How many times did we have to grow the skb on TX. */
 118         unsigned long cnt_encap_on_xmit;      /* How many times did we have to encapsulate the skb on TX. */
 119         struct net_device_stats dev_stats; /* Device stats (rx-bytes, tx-pkts, etc...) */
 120 };
 121
 122 #define VLAN_DEV_INFO(x) ((struct vlan_dev_info *)(x->priv))
 123
 124 /* inline functions */
 125
 126 static inline struct net_device_stats *vlan_dev_get_stats(struct net_device *dev)
 127 {
 128         return &(VLAN_DEV_INFO(dev)->dev_stats);
 129 }
 130
 131 static inline __u32 vlan_get_ingress_priority(struct net_device *dev,
 132                                               unsigned short vlan_tag)
 133 {
 134         struct vlan_dev_info *vip = VLAN_DEV_INFO(dev);
 135
 136         return vip->ingress_priority_map[(vlan_tag >> 13) & 0x7];
 137 }
 138
 139 /* VLAN tx hw acceleration helpers. */
 140 struct vlan_skb_tx_cookie {
 141         u32     magic;
 142         u32     vlan_tag;
 143 };
 144
 145 #define VLAN_TX_COOKIE_MAGIC    0x564c414e      /* "VLAN" in ascii. */
 146 #define VLAN_TX_SKB_CB(__skb)   ((struct vlan_skb_tx_cookie *)&((__skb)->cb[0]))
 147 #define vlan_tx_tag_present(__skb) \
 148         (VLAN_TX_SKB_CB(__skb)->magic == VLAN_TX_COOKIE_MAGIC)
 149 #define vlan_tx_tag_get(__skb)  (VLAN_TX_SKB_CB(__skb)->vlan_tag)
 150
 151 /* VLAN rx hw acceleration helper.  This acts like netif_{rx,receive_skb}(). */
 152 static inline int __vlan_hwaccel_rx(struct sk_buff *skb,
 153                                     struct vlan_group *grp,
 154                                     unsigned short vlan_tag, int polling)
 155 {
 156         struct net_device_stats *stats;
 157
 158         skb->dev = grp->vlan_devices[vlan_tag & VLAN_VID_MASK];
 159         if (skb->dev == NULL) {
 160                 dev_kfree_skb_any(skb);
 161
 162                 /* Not NET_RX_DROP, this is not being dropped
 163                  * due to congestion.
 164                  */
 165                 return 0;
 166         }
 167
 168         skb->dev->last_rx = jiffies;
 169
 170         stats = vlan_dev_get_stats(skb->dev);
 171         stats->rx_packets++;
 172         stats->rx_bytes += skb->len;
 173
 174         skb->priority = vlan_get_ingress_priority(skb->dev, vlan_tag);
 175         switch (skb->pkt_type) {
 176         case PACKET_BROADCAST:
 177                 break;
 178
 179         case PACKET_MULTICAST:
 180                 stats->multicast++;
 181                 break;
 182
 183         case PACKET_OTHERHOST:
 184                 /* Our lower layer thinks this is not local, let's make sure.
 185                  * This allows the VLAN to have a different MAC than the underlying
 186                  * device, and still route correctly.
 187                  */
 188                 if (!memcmp(eth_hdr(skb)->h_dest, skb->dev->dev_addr, ETH_ALEN))
 189                         skb->pkt_type = PACKET_HOST;
 190                 break;
 191         };
 192
 193         return (polling ? netif_receive_skb(skb) : netif_rx(skb));
 194 }
 195
 196 static inline int vlan_hwaccel_rx(struct sk_buff *skb,
 197                                   struct vlan_group *grp,
 198                                   unsigned short vlan_tag)
 199 {
 200         return __vlan_hwaccel_rx(skb, grp, vlan_tag, 0);
 201 }
 202
 203 static inline int vlan_hwaccel_receive_skb(struct sk_buff *skb,
 204                                            struct vlan_group *grp,
 205                                            unsigned short vlan_tag)
 206 {
 207         return __vlan_hwaccel_rx(skb, grp, vlan_tag, 1);
 208 }
 209
 210 /**
 211  * __vlan_put_tag - regular VLAN tag inserting
 212  * @skb: skbuff to tag
 213  * @tag: VLAN tag to insert
 214  *
 215  * Inserts the VLAN tag into @skb as part of the payload
 216  * Returns a VLAN tagged skb. If a new skb is created, @skb is freed.
 217  *
 218  * Following the skb_unshare() example, in case of error, the calling function
 219  * doesn't have to worry about freeing the original skb.
 220  */
 221 static inline struct sk_buff *__vlan_put_tag(struct sk_buff *skb, unsigned short tag)
 222 {
 223         struct vlan_ethhdr *veth;
 224
 225         if (skb_headroom(skb) < VLAN_HLEN) {
 226                 struct sk_buff *sk_tmp = skb;
 227                 skb = skb_realloc_headroom(sk_tmp, VLAN_HLEN);
 228                 kfree_skb(sk_tmp);
 229                 if (!skb) {
 230                         printk(KERN_ERR "vlan: failed to realloc headroom\n");
 231                         return NULL;
 232                 }
 233         } else {
 234                 skb = skb_unshare(skb, GFP_ATOMIC);
 235                 if (!skb) {
 236                         printk(KERN_ERR "vlan: failed to unshare skbuff\n");
 237                         return NULL;
 238                 }
 239         }
 240
 241         veth = (struct vlan_ethhdr *)skb_push(skb, VLAN_HLEN);
 242
 243         /* Move the mac addresses to the beginning of the new header. */
 244         memmove(skb->data, skb->data + VLAN_HLEN, 2 * VLAN_ETH_ALEN);
 245
 246         /* first, the ethernet type */
 247         veth->h_vlan_proto = __constant_htons(ETH_P_8021Q);
 248
 249         /* now, the tag */
 250         veth->h_vlan_TCI = htons(tag);
 251
 252         skb->protocol = __constant_htons(ETH_P_8021Q);
 253         skb->mac.raw -= VLAN_HLEN;
 254         skb->nh.raw -= VLAN_HLEN;
 255
 256         return skb;
 257 }
 258
 259 /**
 260  * __vlan_hwaccel_put_tag - hardware accelerated VLAN inserting
 261  * @skb: skbuff to tag
 262  * @tag: VLAN tag to insert
 263  *
 264  * Puts the VLAN tag in @skb->cb[] and lets the device do the rest
 265  */
 266 static inline struct sk_buff *__vlan_hwaccel_put_tag(struct sk_buff *skb, unsigned short tag)
 267 {
 268         struct vlan_skb_tx_cookie *cookie;
 269
 270         cookie = VLAN_TX_SKB_CB(skb);
 271         cookie->magic = VLAN_TX_COOKIE_MAGIC;
 272         cookie->vlan_tag = tag;
 273
 274         return skb;
 275 }
 276
 277 #define HAVE_VLAN_PUT_TAG
 278
 279 /**
 280  * vlan_put_tag - inserts VLAN tag according to device features
 281  * @skb: skbuff to tag
 282  * @tag: VLAN tag to insert
 283  *
 284  * Assumes skb->dev is the target that will xmit this frame.
 285  * Returns a VLAN tagged skb.
 286  */
 287 static inline struct sk_buff *vlan_put_tag(struct sk_buff *skb, unsigned short tag)
 288 {
 289         if (skb->dev->features & NETIF_F_HW_VLAN_TX) {
 290                 return __vlan_hwaccel_put_tag(skb, tag);
 291         } else {
 292                 return __vlan_put_tag(skb, tag);
 293         }
 294 }
 295
 296 /**
 297  * __vlan_get_tag - get the VLAN ID that is part of the payload
 298  * @skb: skbuff to query
 299  * @tag: buffer to store vlaue
 300  *
 301  * Returns error if the skb is not of VLAN type
 302  */
 303 static inline int __vlan_get_tag(struct sk_buff *skb, unsigned short *tag)
 304 {
 305         struct vlan_ethhdr *veth = (struct vlan_ethhdr *)skb->data;
 306
 307         if (veth->h_vlan_proto != __constant_htons(ETH_P_8021Q)) {
 308                 return -EINVAL;
 309         }
 310
 311         *tag = ntohs(veth->h_vlan_TCI);
 312
 313         return 0;
 314 }
 315
 316 /**
 317  * __vlan_hwaccel_get_tag - get the VLAN ID that is in @skb->cb[]
 318  * @skb: skbuff to query
 319  * @tag: buffer to store vlaue
 320  *
 321  * Returns error if @skb->cb[] is not set correctly
 322  */
 323 static inline int __vlan_hwaccel_get_tag(struct sk_buff *skb, unsigned short *tag)
 324 {
 325         struct vlan_skb_tx_cookie *cookie;
 326
 327         cookie = VLAN_TX_SKB_CB(skb);
 328         if (cookie->magic == VLAN_TX_COOKIE_MAGIC) {
 329                 *tag = cookie->vlan_tag;
 330                 return 0;
 331         } else {
 332                 *tag = 0;
 333                 return -EINVAL;
 334         }
 335 }
 336
 337 #define HAVE_VLAN_GET_TAG
 338
 339 /**
 340  * vlan_get_tag - get the VLAN ID from the skb
 341  * @skb: skbuff to query
 342  * @tag: buffer to store vlaue
 343  *
 344  * Returns error if the skb is not VLAN tagged
 345  */
 346 static inline int vlan_get_tag(struct sk_buff *skb, unsigned short *tag)
 347 {
 348         if (skb->dev->features & NETIF_F_HW_VLAN_TX) {
 349                 return __vlan_hwaccel_get_tag(skb, tag);
 350         } else {
 351                 return __vlan_get_tag(skb, tag);
 352         }
 353 }
 354
 355 #endif /* __KERNEL__ */
 356
 357 /* VLAN IOCTLs are found in sockios.h */
 358
 359 /* Passed in vlan_ioctl_args structure to determine behaviour. */
 360 enum vlan_ioctl_cmds {
 361         ADD_VLAN_CMD,
 362         DEL_VLAN_CMD,
 363         SET_VLAN_INGRESS_PRIORITY_CMD,
 364         SET_VLAN_EGRESS_PRIORITY_CMD,
 365         GET_VLAN_INGRESS_PRIORITY_CMD,
 366         GET_VLAN_EGRESS_PRIORITY_CMD,
 367         SET_VLAN_NAME_TYPE_CMD,
 368         SET_VLAN_FLAG_CMD,
 369         GET_VLAN_REALDEV_NAME_CMD, /* If this works, you know it's a VLAN device, btw */
 370         GET_VLAN_VID_CMD /* Get the VID of this VLAN (specified by name) */
 371 };
 372
 373 enum vlan_name_types {
 374         VLAN_NAME_TYPE_PLUS_VID, /* Name will look like:  vlan0005 */
 375         VLAN_NAME_TYPE_RAW_PLUS_VID, /* name will look like:  eth1.0005 */
 376         VLAN_NAME_TYPE_PLUS_VID_NO_PAD, /* Name will look like:  vlan5 */
 377         VLAN_NAME_TYPE_RAW_PLUS_VID_NO_PAD, /* Name will look like:  eth0.5 */
 378         VLAN_NAME_TYPE_HIGHEST
 379 };
 380
 381 struct vlan_ioctl_args {
 382         int cmd; /* Should be one of the vlan_ioctl_cmds enum above. */
 383         char device1[24];
 384
 385         union {
 386                 char device2[24];
 387                 int VID;
 388                 unsigned int skb_priority;
 389                 unsigned int name_type;
 390                 unsigned int bind_type;
 391                 unsigned int flag; /* Matches vlan_dev_info flags */
 392         } u;
 393
 394         short vlan_qos;
 395 };
 396
 397 #endif /* !(_LINUX_IF_VLAN_H_) */