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
  30#ifdef __KERNEL__
  31extern __be16           eth_type_trans(struct sk_buff *skb, struct net_device *dev);
  32extern const struct header_ops eth_header_ops;
  33
  34extern int eth_header(struct sk_buff *skb, struct net_device *dev,
  35                      unsigned short type,
  36                      const void *daddr, const void *saddr, unsigned len);
  37extern int eth_rebuild_header(struct sk_buff *skb);
  38extern int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr);
  39extern int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh, __be16 type);
  40extern void eth_header_cache_update(struct hh_cache *hh,
  41                                    const struct net_device *dev,
  42                                    const unsigned char *haddr);
  43extern int eth_mac_addr(struct net_device *dev, void *p);
  44extern int eth_change_mtu(struct net_device *dev, int new_mtu);
  45extern int eth_validate_addr(struct net_device *dev);
  46
  47
  48
  49extern struct 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 */
  65static inline bool is_link_local_ether_addr(const u8 *addr)
  66{
  67        __be16 *a = (__be16 *)addr;
  68        static const __be16 *b = (const __be16 *)eth_reserved_addr_base;
  69        static const __be16 m = cpu_to_be16(0xfff0);
  70
  71        return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | ((a[2] ^ b[2]) & m)) == 0;
  72}
  73
  74/**
  75 * is_zero_ether_addr - Determine if give Ethernet address is all zeros.
  76 * @addr: Pointer to a six-byte array containing the Ethernet address
  77 *
  78 * Return true if the address is all zeroes.
  79 */
  80static inline bool is_zero_ether_addr(const u8 *addr)
  81{
  82        return !(addr[0] | addr[1] | addr[2] | addr[3] | addr[4] | addr[5]);
  83}
  84
  85/**
  86 * is_multicast_ether_addr - Determine if the Ethernet address is a multicast.
  87 * @addr: Pointer to a six-byte array containing the Ethernet address
  88 *
  89 * Return true if the address is a multicast address.
  90 * By definition the broadcast address is also a multicast address.
  91 */
  92static inline bool is_multicast_ether_addr(const u8 *addr)
  93{
  94        return 0x01 & addr[0];
  95}
  96
  97/**
  98 * is_local_ether_addr - Determine if the Ethernet address is locally-assigned one (IEEE 802).
  99 * @addr: Pointer to a six-byte array containing the Ethernet address
 100 *
 101 * Return true if the address is a local address.
 102 */
 103static inline bool is_local_ether_addr(const u8 *addr)
 104{
 105        return 0x02 & addr[0];
 106}
 107
 108/**
 109 * is_broadcast_ether_addr - Determine if the Ethernet address is broadcast
 110 * @addr: Pointer to a six-byte array containing the Ethernet address
 111 *
 112 * Return true if the address is the broadcast address.
 113 */
 114static inline bool is_broadcast_ether_addr(const u8 *addr)
 115{
 116        return (addr[0] & addr[1] & addr[2] & addr[3] & addr[4] & addr[5]) == 0xff;
 117}
 118
 119/**
 120 * is_unicast_ether_addr - Determine if the Ethernet address is unicast
 121 * @addr: Pointer to a six-byte array containing the Ethernet address
 122 *
 123 * Return true if the address is a unicast address.
 124 */
 125static inline bool is_unicast_ether_addr(const u8 *addr)
 126{
 127        return !is_multicast_ether_addr(addr);
 128}
 129
 130/**
 131 * is_valid_ether_addr - Determine if the given Ethernet address is valid
 132 * @addr: Pointer to a six-byte array containing the Ethernet address
 133 *
 134 * Check that the Ethernet address (MAC) is not 00:00:00:00:00:00, is not
 135 * a multicast address, and is not FF:FF:FF:FF:FF:FF.
 136 *
 137 * Return true if the address is valid.
 138 */
 139static inline bool is_valid_ether_addr(const u8 *addr)
 140{
 141        /* FF:FF:FF:FF:FF:FF is a multicast address so we don't need to
 142         * explicitly check for it here. */
 143        return !is_multicast_ether_addr(addr) && !is_zero_ether_addr(addr);
 144}
 145
 146/**
 147 * eth_random_addr - Generate software assigned random Ethernet address
 148 * @addr: Pointer to a six-byte array containing the Ethernet address
 149 *
 150 * Generate a random Ethernet address (MAC) that is not multicast
 151 * and has the local assigned bit set.
 152 */
 153static inline void eth_random_addr(u8 *addr)
 154{
 155        get_random_bytes(addr, ETH_ALEN);
 156        addr[0] &= 0xfe;        /* clear multicast bit */
 157        addr[0] |= 0x02;        /* set local assignment bit (IEEE802) */
 158}
 159
 160#define random_ether_addr(addr) eth_random_addr(addr)
 161
 162/**
 163 * eth_broadcast_addr - Assign broadcast address
 164 * @addr: Pointer to a six-byte array containing the Ethernet address
 165 *
 166 * Assign the broadcast address to the given address array.
 167 */
 168static inline void eth_broadcast_addr(u8 *addr)
 169{
 170        memset(addr, 0xff, ETH_ALEN);
 171}
 172
 173/**
 174 * eth_zero_addr - Assign zero address
 175 * @addr: Pointer to a six-byte array containing the Ethernet address
 176 *
 177 * Assign the zero address to the given address array.
 178 */
 179static inline void eth_zero_addr(u8 *addr)
 180{
 181        memset(addr, 0x00, ETH_ALEN);
 182}
 183
 184/**
 185 * eth_hw_addr_random - Generate software assigned random Ethernet and
 186 * set device flag
 187 * @dev: pointer to net_device structure
 188 *
 189 * Generate a random Ethernet address (MAC) to be used by a net device
 190 * and set addr_assign_type so the state can be read by sysfs and be
 191 * used by userspace.
 192 */
 193static inline void eth_hw_addr_random(struct net_device *dev)
 194{
 195        dev->addr_assign_type |= NET_ADDR_RANDOM;
 196        eth_random_addr(dev->dev_addr);
 197}
 198
 199/**
 200 * compare_ether_addr - Compare two Ethernet addresses
 201 * @addr1: Pointer to a six-byte array containing the Ethernet address
 202 * @addr2: Pointer other six-byte array containing the Ethernet address
 203 *
 204 * Compare two Ethernet addresses, returns 0 if equal, non-zero otherwise.
 205 * Unlike memcmp(), it doesn't return a value suitable for sorting.
 206 */
 207static inline unsigned compare_ether_addr(const u8 *addr1, const u8 *addr2)
 208{
 209        const u16 *a = (const u16 *) addr1;
 210        const u16 *b = (const u16 *) addr2;
 211
 212        BUILD_BUG_ON(ETH_ALEN != 6);
 213        return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | (a[2] ^ b[2])) != 0;
 214}
 215
 216/**
 217 * ether_addr_equal - Compare two Ethernet addresses
 218 * @addr1: Pointer to a six-byte array containing the Ethernet address
 219 * @addr2: Pointer other six-byte array containing the Ethernet address
 220 *
 221 * Compare two Ethernet addresses, returns true if equal
 222 */
 223static inline bool ether_addr_equal(const u8 *addr1, const u8 *addr2)
 224{
 225        return !compare_ether_addr(addr1, addr2);
 226}
 227
 228static inline unsigned long zap_last_2bytes(unsigned long value)
 229{
 230#ifdef __BIG_ENDIAN
 231        return value >> 16;
 232#else
 233        return value << 16;
 234#endif
 235}
 236
 237/**
 238 * ether_addr_equal_64bits - Compare two Ethernet addresses
 239 * @addr1: Pointer to an array of 8 bytes
 240 * @addr2: Pointer to an other array of 8 bytes
 241 *
 242 * Compare two Ethernet addresses, returns true if equal, false otherwise.
 243 *
 244 * The function doesn't need any conditional branches and possibly uses
 245 * word memory accesses on CPU allowing cheap unaligned memory reads.
 246 * arrays = { byte1, byte2, byte3, byte4, byte5, byte6, pad1, pad2 }
 247 *
 248 * Please note that alignment of addr1 & addr2 are only guaranteed to be 16 bits.
 249 */
 250
 251static inline bool ether_addr_equal_64bits(const u8 addr1[6+2],
 252                                           const u8 addr2[6+2])
 253{
 254#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
 255        unsigned long fold = ((*(unsigned long *)addr1) ^
 256                              (*(unsigned long *)addr2));
 257
 258        if (sizeof(fold) == 8)
 259                return zap_last_2bytes(fold) == 0;
 260
 261        fold |= zap_last_2bytes((*(unsigned long *)(addr1 + 4)) ^
 262                                (*(unsigned long *)(addr2 + 4)));
 263        return fold == 0;
 264#else
 265        return ether_addr_equal(addr1, addr2);
 266#endif
 267}
 268
 269/**
 270 * is_etherdev_addr - Tell if given Ethernet address belongs to the device.
 271 * @dev: Pointer to a device structure
 272 * @addr: Pointer to a six-byte array containing the Ethernet address
 273 *
 274 * Compare passed address with all addresses of the device. Return true if the
 275 * address if one of the device addresses.
 276 *
 277 * Note that this function calls ether_addr_equal_64bits() so take care of
 278 * the right padding.
 279 */
 280static inline bool is_etherdev_addr(const struct net_device *dev,
 281                                    const u8 addr[6 + 2])
 282{
 283        struct netdev_hw_addr *ha;
 284        bool res = false;
 285
 286        rcu_read_lock();
 287        for_each_dev_addr(dev, ha) {
 288                res = ether_addr_equal_64bits(addr, ha->addr);
 289                if (res)
 290                        break;
 291        }
 292        rcu_read_unlock();
 293        return res;
 294}
 295#endif  /* __KERNEL__ */
 296
 297/**
 298 * compare_ether_header - Compare two Ethernet headers
 299 * @a: Pointer to Ethernet header
 300 * @b: Pointer to Ethernet header
 301 *
 302 * Compare two Ethernet headers, returns 0 if equal.
 303 * This assumes that the network header (i.e., IP header) is 4-byte
 304 * aligned OR the platform can handle unaligned access.  This is the
 305 * case for all packets coming into netif_receive_skb or similar
 306 * entry points.
 307 */
 308
 309static inline unsigned long compare_ether_header(const void *a, const void *b)
 310{
 311#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
 312        unsigned long fold;
 313
 314        /*
 315         * We want to compare 14 bytes:
 316         *  [a0 ... a13] ^ [b0 ... b13]
 317         * Use two long XOR, ORed together, with an overlap of two bytes.
 318         *  [a0  a1  a2  a3  a4  a5  a6  a7 ] ^ [b0  b1  b2  b3  b4  b5  b6  b7 ] |
 319         *  [a6  a7  a8  a9  a10 a11 a12 a13] ^ [b6  b7  b8  b9  b10 b11 b12 b13]
 320         * This means the [a6 a7] ^ [b6 b7] part is done two times.
 321        */
 322        fold = *(unsigned long *)a ^ *(unsigned long *)b;
 323        fold |= *(unsigned long *)(a + 6) ^ *(unsigned long *)(b + 6);
 324        return fold;
 325#else
 326        u32 *a32 = (u32 *)((u8 *)a + 2);
 327        u32 *b32 = (u32 *)((u8 *)b + 2);
 328
 329        return (*(u16 *)a ^ *(u16 *)b) | (a32[0] ^ b32[0]) |
 330               (a32[1] ^ b32[1]) | (a32[2] ^ b32[2]);
 331#endif
 332}
 333
 334#endif  /* _LINUX_ETHERDEVICE_H */
 335
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