linux/include/linux/etherdevice.h
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   1/*
   2 * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3 *              operating system.  NET  is implemented using the  BSD Socket
   4 *              interface as the means of communication with the user level.
   5 *
   6 *              Definitions for the Ethernet handlers.
   7 *
   8 * Version:     @(#)eth.h       1.0.4   05/13/93
   9 *
  10 * Authors:     Ross Biro
  11 *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  12 *
  13 *              Relocated to include/linux where it belongs by Alan Cox 
  14 *                                                      <gw4pts@gw4pts.ampr.org>
  15 *
  16 *              This program is free software; you can redistribute it and/or
  17 *              modify it under the terms of the GNU General Public License
  18 *              as published by the Free Software Foundation; either version
  19 *              2 of the License, or (at your option) any later version.
  20 *
  21 */
  22#ifndef _LINUX_ETHERDEVICE_H
  23#define _LINUX_ETHERDEVICE_H
  24
  25#include <linux/if_ether.h>
  26#include <linux/netdevice.h>
  27#include <linux/random.h>
  28#include <asm/unaligned.h>
  29#include <asm/bitsperlong.h>
  30
  31#ifdef __KERNEL__
  32__be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev);
  33extern const struct header_ops eth_header_ops;
  34
  35int eth_header(struct sk_buff *skb, struct net_device *dev, unsigned short type,
  36               const void *daddr, const void *saddr, unsigned len);
  37int eth_rebuild_header(struct sk_buff *skb);
  38int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr);
  39int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh,
  40                     __be16 type);
  41void eth_header_cache_update(struct hh_cache *hh, const struct net_device *dev,
  42                             const unsigned char *haddr);
  43int eth_prepare_mac_addr_change(struct net_device *dev, void *p);
  44void eth_commit_mac_addr_change(struct net_device *dev, void *p);
  45int eth_mac_addr(struct net_device *dev, void *p);
  46int eth_change_mtu(struct net_device *dev, int new_mtu);
  47int eth_validate_addr(struct net_device *dev);
  48
  49struct net_device *alloc_etherdev_mqs(int sizeof_priv, unsigned int txqs,
  50                                            unsigned int rxqs);
  51#define alloc_etherdev(sizeof_priv) alloc_etherdev_mq(sizeof_priv, 1)
  52#define alloc_etherdev_mq(sizeof_priv, count) alloc_etherdev_mqs(sizeof_priv, count, count)
  53
  54/* Reserved Ethernet Addresses per IEEE 802.1Q */
  55static const u8 eth_reserved_addr_base[ETH_ALEN] __aligned(2) =
  56{ 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 };
  57
  58/**
  59 * is_link_local_ether_addr - Determine if given Ethernet address is link-local
  60 * @addr: Pointer to a six-byte array containing the Ethernet address
  61 *
  62 * Return true if address is link local reserved addr (01:80:c2:00:00:0X) per
  63 * IEEE 802.1Q 8.6.3 Frame filtering.
  64 *
  65 * Please note: addr must be aligned to u16.
  66 */
  67static inline bool is_link_local_ether_addr(const u8 *addr)
  68{
  69        __be16 *a = (__be16 *)addr;
  70        static const __be16 *b = (const __be16 *)eth_reserved_addr_base;
  71        static const __be16 m = cpu_to_be16(0xfff0);
  72
  73#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
  74        return (((*(const u32 *)addr) ^ (*(const u32 *)b)) |
  75                ((a[2] ^ b[2]) & m)) == 0;
  76#else
  77        return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | ((a[2] ^ b[2]) & m)) == 0;
  78#endif
  79}
  80
  81/**
  82 * is_zero_ether_addr - Determine if give Ethernet address is all zeros.
  83 * @addr: Pointer to a six-byte array containing the Ethernet address
  84 *
  85 * Return true if the address is all zeroes.
  86 *
  87 * Please note: addr must be aligned to u16.
  88 */
  89static inline bool is_zero_ether_addr(const u8 *addr)
  90{
  91#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
  92        return ((*(const u32 *)addr) | (*(const u16 *)(addr + 4))) == 0;
  93#else
  94        return (*(const u16 *)(addr + 0) |
  95                *(const u16 *)(addr + 2) |
  96                *(const u16 *)(addr + 4)) == 0;
  97#endif
  98}
  99
 100/**
 101 * is_multicast_ether_addr - Determine if the Ethernet address is a multicast.
 102 * @addr: Pointer to a six-byte array containing the Ethernet address
 103 *
 104 * Return true if the address is a multicast address.
 105 * By definition the broadcast address is also a multicast address.
 106 */
 107static inline bool is_multicast_ether_addr(const u8 *addr)
 108{
 109        return 0x01 & addr[0];
 110}
 111
 112/**
 113 * is_local_ether_addr - Determine if the Ethernet address is locally-assigned one (IEEE 802).
 114 * @addr: Pointer to a six-byte array containing the Ethernet address
 115 *
 116 * Return true if the address is a local address.
 117 */
 118static inline bool is_local_ether_addr(const u8 *addr)
 119{
 120        return 0x02 & addr[0];
 121}
 122
 123/**
 124 * is_broadcast_ether_addr - Determine if the Ethernet address is broadcast
 125 * @addr: Pointer to a six-byte array containing the Ethernet address
 126 *
 127 * Return true if the address is the broadcast address.
 128 *
 129 * Please note: addr must be aligned to u16.
 130 */
 131static inline bool is_broadcast_ether_addr(const u8 *addr)
 132{
 133        return (*(const u16 *)(addr + 0) &
 134                *(const u16 *)(addr + 2) &
 135                *(const u16 *)(addr + 4)) == 0xffff;
 136}
 137
 138/**
 139 * is_unicast_ether_addr - Determine if the Ethernet address is unicast
 140 * @addr: Pointer to a six-byte array containing the Ethernet address
 141 *
 142 * Return true if the address is a unicast address.
 143 */
 144static inline bool is_unicast_ether_addr(const u8 *addr)
 145{
 146        return !is_multicast_ether_addr(addr);
 147}
 148
 149/**
 150 * is_valid_ether_addr - Determine if the given Ethernet address is valid
 151 * @addr: Pointer to a six-byte array containing the Ethernet address
 152 *
 153 * Check that the Ethernet address (MAC) is not 00:00:00:00:00:00, is not
 154 * a multicast address, and is not FF:FF:FF:FF:FF:FF.
 155 *
 156 * Return true if the address is valid.
 157 *
 158 * Please note: addr must be aligned to u16.
 159 */
 160static inline bool is_valid_ether_addr(const u8 *addr)
 161{
 162        /* FF:FF:FF:FF:FF:FF is a multicast address so we don't need to
 163         * explicitly check for it here. */
 164        return !is_multicast_ether_addr(addr) && !is_zero_ether_addr(addr);
 165}
 166
 167/**
 168 * eth_random_addr - Generate software assigned random Ethernet address
 169 * @addr: Pointer to a six-byte array containing the Ethernet address
 170 *
 171 * Generate a random Ethernet address (MAC) that is not multicast
 172 * and has the local assigned bit set.
 173 */
 174static inline void eth_random_addr(u8 *addr)
 175{
 176        get_random_bytes(addr, ETH_ALEN);
 177        addr[0] &= 0xfe;        /* clear multicast bit */
 178        addr[0] |= 0x02;        /* set local assignment bit (IEEE802) */
 179}
 180
 181#define random_ether_addr(addr) eth_random_addr(addr)
 182
 183/**
 184 * eth_broadcast_addr - Assign broadcast address
 185 * @addr: Pointer to a six-byte array containing the Ethernet address
 186 *
 187 * Assign the broadcast address to the given address array.
 188 */
 189static inline void eth_broadcast_addr(u8 *addr)
 190{
 191        memset(addr, 0xff, ETH_ALEN);
 192}
 193
 194/**
 195 * eth_zero_addr - Assign zero address
 196 * @addr: Pointer to a six-byte array containing the Ethernet address
 197 *
 198 * Assign the zero address to the given address array.
 199 */
 200static inline void eth_zero_addr(u8 *addr)
 201{
 202        memset(addr, 0x00, ETH_ALEN);
 203}
 204
 205/**
 206 * eth_hw_addr_random - Generate software assigned random Ethernet and
 207 * set device flag
 208 * @dev: pointer to net_device structure
 209 *
 210 * Generate a random Ethernet address (MAC) to be used by a net device
 211 * and set addr_assign_type so the state can be read by sysfs and be
 212 * used by userspace.
 213 */
 214static inline void eth_hw_addr_random(struct net_device *dev)
 215{
 216        dev->addr_assign_type = NET_ADDR_RANDOM;
 217        eth_random_addr(dev->dev_addr);
 218}
 219
 220/**
 221 * ether_addr_copy - Copy an Ethernet address
 222 * @dst: Pointer to a six-byte array Ethernet address destination
 223 * @src: Pointer to a six-byte array Ethernet address source
 224 *
 225 * Please note: dst & src must both be aligned to u16.
 226 */
 227static inline void ether_addr_copy(u8 *dst, const u8 *src)
 228{
 229#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
 230        *(u32 *)dst = *(const u32 *)src;
 231        *(u16 *)(dst + 4) = *(const u16 *)(src + 4);
 232#else
 233        u16 *a = (u16 *)dst;
 234        const u16 *b = (const u16 *)src;
 235
 236        a[0] = b[0];
 237        a[1] = b[1];
 238        a[2] = b[2];
 239#endif
 240}
 241
 242/**
 243 * eth_hw_addr_inherit - Copy dev_addr from another net_device
 244 * @dst: pointer to net_device to copy dev_addr to
 245 * @src: pointer to net_device to copy dev_addr from
 246 *
 247 * Copy the Ethernet address from one net_device to another along with
 248 * the address attributes (addr_assign_type).
 249 */
 250static inline void eth_hw_addr_inherit(struct net_device *dst,
 251                                       struct net_device *src)
 252{
 253        dst->addr_assign_type = src->addr_assign_type;
 254        ether_addr_copy(dst->dev_addr, src->dev_addr);
 255}
 256
 257/**
 258 * ether_addr_equal - Compare two Ethernet addresses
 259 * @addr1: Pointer to a six-byte array containing the Ethernet address
 260 * @addr2: Pointer other six-byte array containing the Ethernet address
 261 *
 262 * Compare two Ethernet addresses, returns true if equal
 263 *
 264 * Please note: addr1 & addr2 must both be aligned to u16.
 265 */
 266static inline bool ether_addr_equal(const u8 *addr1, const u8 *addr2)
 267{
 268#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
 269        u32 fold = ((*(const u32 *)addr1) ^ (*(const u32 *)addr2)) |
 270                   ((*(const u16 *)(addr1 + 4)) ^ (*(const u16 *)(addr2 + 4)));
 271
 272        return fold == 0;
 273#else
 274        const u16 *a = (const u16 *)addr1;
 275        const u16 *b = (const u16 *)addr2;
 276
 277        return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | (a[2] ^ b[2])) == 0;
 278#endif
 279}
 280
 281/**
 282 * ether_addr_equal_64bits - Compare two Ethernet addresses
 283 * @addr1: Pointer to an array of 8 bytes
 284 * @addr2: Pointer to an other array of 8 bytes
 285 *
 286 * Compare two Ethernet addresses, returns true if equal, false otherwise.
 287 *
 288 * The function doesn't need any conditional branches and possibly uses
 289 * word memory accesses on CPU allowing cheap unaligned memory reads.
 290 * arrays = { byte1, byte2, byte3, byte4, byte5, byte6, pad1, pad2 }
 291 *
 292 * Please note that alignment of addr1 & addr2 are only guaranteed to be 16 bits.
 293 */
 294
 295static inline bool ether_addr_equal_64bits(const u8 addr1[6+2],
 296                                           const u8 addr2[6+2])
 297{
 298#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
 299        u64 fold = (*(const u64 *)addr1) ^ (*(const u64 *)addr2);
 300
 301#ifdef __BIG_ENDIAN
 302        return (fold >> 16) == 0;
 303#else
 304        return (fold << 16) == 0;
 305#endif
 306#else
 307        return ether_addr_equal(addr1, addr2);
 308#endif
 309}
 310
 311/**
 312 * ether_addr_equal_unaligned - Compare two not u16 aligned Ethernet addresses
 313 * @addr1: Pointer to a six-byte array containing the Ethernet address
 314 * @addr2: Pointer other six-byte array containing the Ethernet address
 315 *
 316 * Compare two Ethernet addresses, returns true if equal
 317 *
 318 * Please note: Use only when any Ethernet address may not be u16 aligned.
 319 */
 320static inline bool ether_addr_equal_unaligned(const u8 *addr1, const u8 *addr2)
 321{
 322#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
 323        return ether_addr_equal(addr1, addr2);
 324#else
 325        return memcmp(addr1, addr2, ETH_ALEN) == 0;
 326#endif
 327}
 328
 329/**
 330 * is_etherdev_addr - Tell if given Ethernet address belongs to the device.
 331 * @dev: Pointer to a device structure
 332 * @addr: Pointer to a six-byte array containing the Ethernet address
 333 *
 334 * Compare passed address with all addresses of the device. Return true if the
 335 * address if one of the device addresses.
 336 *
 337 * Note that this function calls ether_addr_equal_64bits() so take care of
 338 * the right padding.
 339 */
 340static inline bool is_etherdev_addr(const struct net_device *dev,
 341                                    const u8 addr[6 + 2])
 342{
 343        struct netdev_hw_addr *ha;
 344        bool res = false;
 345
 346        rcu_read_lock();
 347        for_each_dev_addr(dev, ha) {
 348                res = ether_addr_equal_64bits(addr, ha->addr);
 349                if (res)
 350                        break;
 351        }
 352        rcu_read_unlock();
 353        return res;
 354}
 355#endif  /* __KERNEL__ */
 356
 357/**
 358 * compare_ether_header - Compare two Ethernet headers
 359 * @a: Pointer to Ethernet header
 360 * @b: Pointer to Ethernet header
 361 *
 362 * Compare two Ethernet headers, returns 0 if equal.
 363 * This assumes that the network header (i.e., IP header) is 4-byte
 364 * aligned OR the platform can handle unaligned access.  This is the
 365 * case for all packets coming into netif_receive_skb or similar
 366 * entry points.
 367 */
 368
 369static inline unsigned long compare_ether_header(const void *a, const void *b)
 370{
 371#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
 372        unsigned long fold;
 373
 374        /*
 375         * We want to compare 14 bytes:
 376         *  [a0 ... a13] ^ [b0 ... b13]
 377         * Use two long XOR, ORed together, with an overlap of two bytes.
 378         *  [a0  a1  a2  a3  a4  a5  a6  a7 ] ^ [b0  b1  b2  b3  b4  b5  b6  b7 ] |
 379         *  [a6  a7  a8  a9  a10 a11 a12 a13] ^ [b6  b7  b8  b9  b10 b11 b12 b13]
 380         * This means the [a6 a7] ^ [b6 b7] part is done two times.
 381        */
 382        fold = *(unsigned long *)a ^ *(unsigned long *)b;
 383        fold |= *(unsigned long *)(a + 6) ^ *(unsigned long *)(b + 6);
 384        return fold;
 385#else
 386        u32 *a32 = (u32 *)((u8 *)a + 2);
 387        u32 *b32 = (u32 *)((u8 *)b + 2);
 388
 389        return (*(u16 *)a ^ *(u16 *)b) | (a32[0] ^ b32[0]) |
 390               (a32[1] ^ b32[1]) | (a32[2] ^ b32[2]);
 391#endif
 392}
 393
 394#endif  /* _LINUX_ETHERDEVICE_H */
 395
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