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__
  32u32 eth_get_headlen(void *data, unsigned int max_len);
  33__be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev);
  34extern const struct header_ops eth_header_ops;
  35
  36int eth_header(struct sk_buff *skb, struct net_device *dev, unsigned short type,
  37               const void *daddr, const void *saddr, unsigned len);
  38int eth_rebuild_header(struct sk_buff *skb);
  39int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr);
  40int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh,
  41                     __be16 type);
  42void eth_header_cache_update(struct hh_cache *hh, const struct net_device *dev,
  43                             const unsigned char *haddr);
  44int eth_prepare_mac_addr_change(struct net_device *dev, void *p);
  45void eth_commit_mac_addr_change(struct net_device *dev, void *p);
  46int eth_mac_addr(struct net_device *dev, void *p);
  47int eth_change_mtu(struct net_device *dev, int new_mtu);
  48int eth_validate_addr(struct net_device *dev);
  49
  50struct net_device *alloc_etherdev_mqs(int sizeof_priv, unsigned int txqs,
  51                                            unsigned int rxqs);
  52#define alloc_etherdev(sizeof_priv) alloc_etherdev_mq(sizeof_priv, 1)
  53#define alloc_etherdev_mq(sizeof_priv, count) alloc_etherdev_mqs(sizeof_priv, count, count)
  54
  55/* Reserved Ethernet Addresses per IEEE 802.1Q */
  56static const u8 eth_reserved_addr_base[ETH_ALEN] __aligned(2) =
  57{ 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 };
  58
  59/**
  60 * is_link_local_ether_addr - Determine if given Ethernet address is link-local
  61 * @addr: Pointer to a six-byte array containing the Ethernet address
  62 *
  63 * Return true if address is link local reserved addr (01:80:c2:00:00:0X) per
  64 * IEEE 802.1Q 8.6.3 Frame filtering.
  65 *
  66 * Please note: addr must be aligned to u16.
  67 */
  68static inline bool is_link_local_ether_addr(const u8 *addr)
  69{
  70        __be16 *a = (__be16 *)addr;
  71        static const __be16 *b = (const __be16 *)eth_reserved_addr_base;
  72        static const __be16 m = cpu_to_be16(0xfff0);
  73
  74#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
  75        return (((*(const u32 *)addr) ^ (*(const u32 *)b)) |
  76                ((a[2] ^ b[2]) & m)) == 0;
  77#else
  78        return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | ((a[2] ^ b[2]) & m)) == 0;
  79#endif
  80}
  81
  82/**
  83 * is_zero_ether_addr - Determine if give Ethernet address is all zeros.
  84 * @addr: Pointer to a six-byte array containing the Ethernet address
  85 *
  86 * Return true if the address is all zeroes.
  87 *
  88 * Please note: addr must be aligned to u16.
  89 */
  90static inline bool is_zero_ether_addr(const u8 *addr)
  91{
  92#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
  93        return ((*(const u32 *)addr) | (*(const u16 *)(addr + 4))) == 0;
  94#else
  95        return (*(const u16 *)(addr + 0) |
  96                *(const u16 *)(addr + 2) |
  97                *(const u16 *)(addr + 4)) == 0;
  98#endif
  99}
 100
 101/**
 102 * is_multicast_ether_addr - Determine if the Ethernet address is a multicast.
 103 * @addr: Pointer to a six-byte array containing the Ethernet address
 104 *
 105 * Return true if the address is a multicast address.
 106 * By definition the broadcast address is also a multicast address.
 107 */
 108static inline bool is_multicast_ether_addr(const u8 *addr)
 109{
 110        return 0x01 & addr[0];
 111}
 112
 113/**
 114 * is_local_ether_addr - Determine if the Ethernet address is locally-assigned one (IEEE 802).
 115 * @addr: Pointer to a six-byte array containing the Ethernet address
 116 *
 117 * Return true if the address is a local address.
 118 */
 119static inline bool is_local_ether_addr(const u8 *addr)
 120{
 121        return 0x02 & addr[0];
 122}
 123
 124/**
 125 * is_broadcast_ether_addr - Determine if the Ethernet address is broadcast
 126 * @addr: Pointer to a six-byte array containing the Ethernet address
 127 *
 128 * Return true if the address is the broadcast address.
 129 *
 130 * Please note: addr must be aligned to u16.
 131 */
 132static inline bool is_broadcast_ether_addr(const u8 *addr)
 133{
 134        return (*(const u16 *)(addr + 0) &
 135                *(const u16 *)(addr + 2) &
 136                *(const u16 *)(addr + 4)) == 0xffff;
 137}
 138
 139/**
 140 * is_unicast_ether_addr - Determine if the Ethernet address is unicast
 141 * @addr: Pointer to a six-byte array containing the Ethernet address
 142 *
 143 * Return true if the address is a unicast address.
 144 */
 145static inline bool is_unicast_ether_addr(const u8 *addr)
 146{
 147        return !is_multicast_ether_addr(addr);
 148}
 149
 150/**
 151 * is_valid_ether_addr - Determine if the given Ethernet address is valid
 152 * @addr: Pointer to a six-byte array containing the Ethernet address
 153 *
 154 * Check that the Ethernet address (MAC) is not 00:00:00:00:00:00, is not
 155 * a multicast address, and is not FF:FF:FF:FF:FF:FF.
 156 *
 157 * Return true if the address is valid.
 158 *
 159 * Please note: addr must be aligned to u16.
 160 */
 161static inline bool is_valid_ether_addr(const u8 *addr)
 162{
 163        /* FF:FF:FF:FF:FF:FF is a multicast address so we don't need to
 164         * explicitly check for it here. */
 165        return !is_multicast_ether_addr(addr) && !is_zero_ether_addr(addr);
 166}
 167
 168/**
 169 * eth_random_addr - Generate software assigned random Ethernet address
 170 * @addr: Pointer to a six-byte array containing the Ethernet address
 171 *
 172 * Generate a random Ethernet address (MAC) that is not multicast
 173 * and has the local assigned bit set.
 174 */
 175static inline void eth_random_addr(u8 *addr)
 176{
 177        get_random_bytes(addr, ETH_ALEN);
 178        addr[0] &= 0xfe;        /* clear multicast bit */
 179        addr[0] |= 0x02;        /* set local assignment bit (IEEE802) */
 180}
 181
 182#define random_ether_addr(addr) eth_random_addr(addr)
 183
 184/**
 185 * eth_broadcast_addr - Assign broadcast address
 186 * @addr: Pointer to a six-byte array containing the Ethernet address
 187 *
 188 * Assign the broadcast address to the given address array.
 189 */
 190static inline void eth_broadcast_addr(u8 *addr)
 191{
 192        memset(addr, 0xff, ETH_ALEN);
 193}
 194
 195/**
 196 * eth_zero_addr - Assign zero address
 197 * @addr: Pointer to a six-byte array containing the Ethernet address
 198 *
 199 * Assign the zero address to the given address array.
 200 */
 201static inline void eth_zero_addr(u8 *addr)
 202{
 203        memset(addr, 0x00, ETH_ALEN);
 204}
 205
 206/**
 207 * eth_hw_addr_random - Generate software assigned random Ethernet and
 208 * set device flag
 209 * @dev: pointer to net_device structure
 210 *
 211 * Generate a random Ethernet address (MAC) to be used by a net device
 212 * and set addr_assign_type so the state can be read by sysfs and be
 213 * used by userspace.
 214 */
 215static inline void eth_hw_addr_random(struct net_device *dev)
 216{
 217        dev->addr_assign_type = NET_ADDR_RANDOM;
 218        eth_random_addr(dev->dev_addr);
 219}
 220
 221/**
 222 * ether_addr_copy - Copy an Ethernet address
 223 * @dst: Pointer to a six-byte array Ethernet address destination
 224 * @src: Pointer to a six-byte array Ethernet address source
 225 *
 226 * Please note: dst & src must both be aligned to u16.
 227 */
 228static inline void ether_addr_copy(u8 *dst, const u8 *src)
 229{
 230#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
 231        *(u32 *)dst = *(const u32 *)src;
 232        *(u16 *)(dst + 4) = *(const u16 *)(src + 4);
 233#else
 234        u16 *a = (u16 *)dst;
 235        const u16 *b = (const u16 *)src;
 236
 237        a[0] = b[0];
 238        a[1] = b[1];
 239        a[2] = b[2];
 240#endif
 241}
 242
 243/**
 244 * eth_hw_addr_inherit - Copy dev_addr from another net_device
 245 * @dst: pointer to net_device to copy dev_addr to
 246 * @src: pointer to net_device to copy dev_addr from
 247 *
 248 * Copy the Ethernet address from one net_device to another along with
 249 * the address attributes (addr_assign_type).
 250 */
 251static inline void eth_hw_addr_inherit(struct net_device *dst,
 252                                       struct net_device *src)
 253{
 254        dst->addr_assign_type = src->addr_assign_type;
 255        ether_addr_copy(dst->dev_addr, src->dev_addr);
 256}
 257
 258/**
 259 * ether_addr_equal - Compare two Ethernet addresses
 260 * @addr1: Pointer to a six-byte array containing the Ethernet address
 261 * @addr2: Pointer other six-byte array containing the Ethernet address
 262 *
 263 * Compare two Ethernet addresses, returns true if equal
 264 *
 265 * Please note: addr1 & addr2 must both be aligned to u16.
 266 */
 267static inline bool ether_addr_equal(const u8 *addr1, const u8 *addr2)
 268{
 269#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
 270        u32 fold = ((*(const u32 *)addr1) ^ (*(const u32 *)addr2)) |
 271                   ((*(const u16 *)(addr1 + 4)) ^ (*(const u16 *)(addr2 + 4)));
 272
 273        return fold == 0;
 274#else
 275        const u16 *a = (const u16 *)addr1;
 276        const u16 *b = (const u16 *)addr2;
 277
 278        return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | (a[2] ^ b[2])) == 0;
 279#endif
 280}
 281
 282/**
 283 * ether_addr_equal_64bits - Compare two Ethernet addresses
 284 * @addr1: Pointer to an array of 8 bytes
 285 * @addr2: Pointer to an other array of 8 bytes
 286 *
 287 * Compare two Ethernet addresses, returns true if equal, false otherwise.
 288 *
 289 * The function doesn't need any conditional branches and possibly uses
 290 * word memory accesses on CPU allowing cheap unaligned memory reads.
 291 * arrays = { byte1, byte2, byte3, byte4, byte5, byte6, pad1, pad2 }
 292 *
 293 * Please note that alignment of addr1 & addr2 are only guaranteed to be 16 bits.
 294 */
 295
 296static inline bool ether_addr_equal_64bits(const u8 addr1[6+2],
 297                                           const u8 addr2[6+2])
 298{
 299#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
 300        u64 fold = (*(const u64 *)addr1) ^ (*(const u64 *)addr2);
 301
 302#ifdef __BIG_ENDIAN
 303        return (fold >> 16) == 0;
 304#else
 305        return (fold << 16) == 0;
 306#endif
 307#else
 308        return ether_addr_equal(addr1, addr2);
 309#endif
 310}
 311
 312/**
 313 * ether_addr_equal_unaligned - Compare two not u16 aligned Ethernet addresses
 314 * @addr1: Pointer to a six-byte array containing the Ethernet address
 315 * @addr2: Pointer other six-byte array containing the Ethernet address
 316 *
 317 * Compare two Ethernet addresses, returns true if equal
 318 *
 319 * Please note: Use only when any Ethernet address may not be u16 aligned.
 320 */
 321static inline bool ether_addr_equal_unaligned(const u8 *addr1, const u8 *addr2)
 322{
 323#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
 324        return ether_addr_equal(addr1, addr2);
 325#else
 326        return memcmp(addr1, addr2, ETH_ALEN) == 0;
 327#endif
 328}
 329
 330/**
 331 * is_etherdev_addr - Tell if given Ethernet address belongs to the device.
 332 * @dev: Pointer to a device structure
 333 * @addr: Pointer to a six-byte array containing the Ethernet address
 334 *
 335 * Compare passed address with all addresses of the device. Return true if the
 336 * address if one of the device addresses.
 337 *
 338 * Note that this function calls ether_addr_equal_64bits() so take care of
 339 * the right padding.
 340 */
 341static inline bool is_etherdev_addr(const struct net_device *dev,
 342                                    const u8 addr[6 + 2])
 343{
 344        struct netdev_hw_addr *ha;
 345        bool res = false;
 346
 347        rcu_read_lock();
 348        for_each_dev_addr(dev, ha) {
 349                res = ether_addr_equal_64bits(addr, ha->addr);
 350                if (res)
 351                        break;
 352        }
 353        rcu_read_unlock();
 354        return res;
 355}
 356#endif  /* __KERNEL__ */
 357
 358/**
 359 * compare_ether_header - Compare two Ethernet headers
 360 * @a: Pointer to Ethernet header
 361 * @b: Pointer to Ethernet header
 362 *
 363 * Compare two Ethernet headers, returns 0 if equal.
 364 * This assumes that the network header (i.e., IP header) is 4-byte
 365 * aligned OR the platform can handle unaligned access.  This is the
 366 * case for all packets coming into netif_receive_skb or similar
 367 * entry points.
 368 */
 369
 370static inline unsigned long compare_ether_header(const void *a, const void *b)
 371{
 372#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
 373        unsigned long fold;
 374
 375        /*
 376         * We want to compare 14 bytes:
 377         *  [a0 ... a13] ^ [b0 ... b13]
 378         * Use two long XOR, ORed together, with an overlap of two bytes.
 379         *  [a0  a1  a2  a3  a4  a5  a6  a7 ] ^ [b0  b1  b2  b3  b4  b5  b6  b7 ] |
 380         *  [a6  a7  a8  a9  a10 a11 a12 a13] ^ [b6  b7  b8  b9  b10 b11 b12 b13]
 381         * This means the [a6 a7] ^ [b6 b7] part is done two times.
 382        */
 383        fold = *(unsigned long *)a ^ *(unsigned long *)b;
 384        fold |= *(unsigned long *)(a + 6) ^ *(unsigned long *)(b + 6);
 385        return fold;
 386#else
 387        u32 *a32 = (u32 *)((u8 *)a + 2);
 388        u32 *b32 = (u32 *)((u8 *)b + 2);
 389
 390        return (*(u16 *)a ^ *(u16 *)b) | (a32[0] ^ b32[0]) |
 391               (a32[1] ^ b32[1]) | (a32[2] ^ b32[2]);
 392#endif
 393}
 394
 395/**
 396 * eth_skb_pad - Pad buffer to mininum number of octets for Ethernet frame
 397 * @skb: Buffer to pad
 398 *
 399 * An Ethernet frame should have a minimum size of 60 bytes.  This function
 400 * takes short frames and pads them with zeros up to the 60 byte limit.
 401 */
 402static inline int eth_skb_pad(struct sk_buff *skb)
 403{
 404        return skb_put_padto(skb, ETH_ZLEN);
 405}
 406
 407#endif  /* _LINUX_ETHERDEVICE_H */
 408
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