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/netdevice.h>
  27 #include <linux/etherdevice.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    __be16               h_vlan_proto;              /* Should always be 0x8100 */
  46    __be16               h_vlan_TCI;                /* Encapsulates priority and VLAN ID */
  47    __be16               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    __be16               h_vlan_TCI;                /* Encapsulates priority and VLAN ID */
  59    __be16               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         if (skb_bond_should_drop(skb)) {
 159                 dev_kfree_skb_any(skb);
 160                 return NET_RX_DROP;
 161         }
 162
 163         skb->dev = grp->vlan_devices[vlan_tag & VLAN_VID_MASK];
 164         if (skb->dev == NULL) {
 165                 dev_kfree_skb_any(skb);
 166
 167                 /* Not NET_RX_DROP, this is not being dropped
 168                  * due to congestion.
 169                  */
 170                 return 0;
 171         }
 172
 173         skb->dev->last_rx = jiffies;
 174
 175         stats = vlan_dev_get_stats(skb->dev);
 176         stats->rx_packets++;
 177         stats->rx_bytes += skb->len;
 178
 179         skb->priority = vlan_get_ingress_priority(skb->dev, vlan_tag);
 180         switch (skb->pkt_type) {
 181         case PACKET_BROADCAST:
 182                 break;
 183
 184         case PACKET_MULTICAST:
 185                 stats->multicast++;
 186                 break;
 187
 188         case PACKET_OTHERHOST:
 189                 /* Our lower layer thinks this is not local, let's make sure.
 190                  * This allows the VLAN to have a different MAC than the underlying
 191                  * device, and still route correctly.
 192                  */
 193                 if (!compare_ether_addr(eth_hdr(skb)->h_dest,
 194                                         skb->dev->dev_addr))
 195                         skb->pkt_type = PACKET_HOST;
 196                 break;
 197         };
 198
 199         return (polling ? netif_receive_skb(skb) : netif_rx(skb));
 200 }
 201
 202 static inline int vlan_hwaccel_rx(struct sk_buff *skb,
 203                                   struct vlan_group *grp,
 204                                   unsigned short vlan_tag)
 205 {
 206         return __vlan_hwaccel_rx(skb, grp, vlan_tag, 0);
 207 }
 208
 209 static inline int vlan_hwaccel_receive_skb(struct sk_buff *skb,
 210                                            struct vlan_group *grp,
 211                                            unsigned short vlan_tag)
 212 {
 213         return __vlan_hwaccel_rx(skb, grp, vlan_tag, 1);
 214 }
 215
 216 /**
 217  * __vlan_put_tag - regular VLAN tag inserting
 218  * @skb: skbuff to tag
 219  * @tag: VLAN tag to insert
 220  *
 221  * Inserts the VLAN tag into @skb as part of the payload
 222  * Returns a VLAN tagged skb. If a new skb is created, @skb is freed.
 223  *
 224  * Following the skb_unshare() example, in case of error, the calling function
 225  * doesn't have to worry about freeing the original skb.
 226  */
 227 static inline struct sk_buff *__vlan_put_tag(struct sk_buff *skb, unsigned short tag)
 228 {
 229         struct vlan_ethhdr *veth;
 230
 231         if (skb_headroom(skb) < VLAN_HLEN) {
 232                 struct sk_buff *sk_tmp = skb;
 233                 skb = skb_realloc_headroom(sk_tmp, VLAN_HLEN);
 234                 kfree_skb(sk_tmp);
 235                 if (!skb) {
 236                         printk(KERN_ERR "vlan: failed to realloc headroom\n");
 237                         return NULL;
 238                 }
 239         } else {
 240                 skb = skb_unshare(skb, GFP_ATOMIC);
 241                 if (!skb) {
 242                         printk(KERN_ERR "vlan: failed to unshare skbuff\n");
 243                         return NULL;
 244                 }
 245         }
 246
 247         veth = (struct vlan_ethhdr *)skb_push(skb, VLAN_HLEN);
 248
 249         /* Move the mac addresses to the beginning of the new header. */
 250         memmove(skb->data, skb->data + VLAN_HLEN, 2 * VLAN_ETH_ALEN);
 251
 252         /* first, the ethernet type */
 253         veth->h_vlan_proto = __constant_htons(ETH_P_8021Q);
 254
 255         /* now, the tag */
 256         veth->h_vlan_TCI = htons(tag);
 257
 258         skb->protocol = __constant_htons(ETH_P_8021Q);
 259         skb->mac.raw -= VLAN_HLEN;
 260         skb->nh.raw -= VLAN_HLEN;
 261
 262         return skb;
 263 }
 264
 265 /**
 266  * __vlan_hwaccel_put_tag - hardware accelerated VLAN inserting
 267  * @skb: skbuff to tag
 268  * @tag: VLAN tag to insert
 269  *
 270  * Puts the VLAN tag in @skb->cb[] and lets the device do the rest
 271  */
 272 static inline struct sk_buff *__vlan_hwaccel_put_tag(struct sk_buff *skb, unsigned short tag)
 273 {
 274         struct vlan_skb_tx_cookie *cookie;
 275
 276         cookie = VLAN_TX_SKB_CB(skb);
 277         cookie->magic = VLAN_TX_COOKIE_MAGIC;
 278         cookie->vlan_tag = tag;
 279
 280         return skb;
 281 }
 282
 283 #define HAVE_VLAN_PUT_TAG
 284
 285 /**
 286  * vlan_put_tag - inserts VLAN tag according to device features
 287  * @skb: skbuff to tag
 288  * @tag: VLAN tag to insert
 289  *
 290  * Assumes skb->dev is the target that will xmit this frame.
 291  * Returns a VLAN tagged skb.
 292  */
 293 static inline struct sk_buff *vlan_put_tag(struct sk_buff *skb, unsigned short tag)
 294 {
 295         if (skb->dev->features & NETIF_F_HW_VLAN_TX) {
 296                 return __vlan_hwaccel_put_tag(skb, tag);
 297         } else {
 298                 return __vlan_put_tag(skb, tag);
 299         }
 300 }
 301
 302 /**
 303  * __vlan_get_tag - get the VLAN ID that is part of the payload
 304  * @skb: skbuff to query
 305  * @tag: buffer to store vlaue
 306  *
 307  * Returns error if the skb is not of VLAN type
 308  */
 309 static inline int __vlan_get_tag(struct sk_buff *skb, unsigned short *tag)
 310 {
 311         struct vlan_ethhdr *veth = (struct vlan_ethhdr *)skb->data;
 312
 313         if (veth->h_vlan_proto != __constant_htons(ETH_P_8021Q)) {
 314                 return -EINVAL;
 315         }
 316
 317         *tag = ntohs(veth->h_vlan_TCI);
 318
 319         return 0;
 320 }
 321
 322 /**
 323  * __vlan_hwaccel_get_tag - get the VLAN ID that is in @skb->cb[]
 324  * @skb: skbuff to query
 325  * @tag: buffer to store vlaue
 326  *
 327  * Returns error if @skb->cb[] is not set correctly
 328  */
 329 static inline int __vlan_hwaccel_get_tag(struct sk_buff *skb, unsigned short *tag)
 330 {
 331         struct vlan_skb_tx_cookie *cookie;
 332
 333         cookie = VLAN_TX_SKB_CB(skb);
 334         if (cookie->magic == VLAN_TX_COOKIE_MAGIC) {
 335                 *tag = cookie->vlan_tag;
 336                 return 0;
 337         } else {
 338                 *tag = 0;
 339                 return -EINVAL;
 340         }
 341 }
 342
 343 #define HAVE_VLAN_GET_TAG
 344
 345 /**
 346  * vlan_get_tag - get the VLAN ID from the skb
 347  * @skb: skbuff to query
 348  * @tag: buffer to store vlaue
 349  *
 350  * Returns error if the skb is not VLAN tagged
 351  */
 352 static inline int vlan_get_tag(struct sk_buff *skb, unsigned short *tag)
 353 {
 354         if (skb->dev->features & NETIF_F_HW_VLAN_TX) {
 355                 return __vlan_hwaccel_get_tag(skb, tag);
 356         } else {
 357                 return __vlan_get_tag(skb, tag);
 358         }
 359 }
 360
 361 #endif /* __KERNEL__ */
 362
 363 /* VLAN IOCTLs are found in sockios.h */
 364
 365 /* Passed in vlan_ioctl_args structure to determine behaviour. */
 366 enum vlan_ioctl_cmds {
 367         ADD_VLAN_CMD,
 368         DEL_VLAN_CMD,
 369         SET_VLAN_INGRESS_PRIORITY_CMD,
 370         SET_VLAN_EGRESS_PRIORITY_CMD,
 371         GET_VLAN_INGRESS_PRIORITY_CMD,
 372         GET_VLAN_EGRESS_PRIORITY_CMD,
 373         SET_VLAN_NAME_TYPE_CMD,
 374         SET_VLAN_FLAG_CMD,
 375         GET_VLAN_REALDEV_NAME_CMD, /* If this works, you know it's a VLAN device, btw */
 376         GET_VLAN_VID_CMD /* Get the VID of this VLAN (specified by name) */
 377 };
 378
 379 enum vlan_name_types {
 380         VLAN_NAME_TYPE_PLUS_VID, /* Name will look like:  vlan0005 */
 381         VLAN_NAME_TYPE_RAW_PLUS_VID, /* name will look like:  eth1.0005 */
 382         VLAN_NAME_TYPE_PLUS_VID_NO_PAD, /* Name will look like:  vlan5 */
 383         VLAN_NAME_TYPE_RAW_PLUS_VID_NO_PAD, /* Name will look like:  eth0.5 */
 384         VLAN_NAME_TYPE_HIGHEST
 385 };
 386
 387 struct vlan_ioctl_args {
 388         int cmd; /* Should be one of the vlan_ioctl_cmds enum above. */
 389         char device1[24];
 390
 391         union {
 392                 char device2[24];
 393                 int VID;
 394                 unsigned int skb_priority;
 395                 unsigned int name_type;
 396                 unsigned int bind_type;
 397                 unsigned int flag; /* Matches vlan_dev_info flags */
 398         } u;
 399
 400         short vlan_qos;
 401 };
 402
 403 #endif /* !(_LINUX_IF_VLAN_H_) */