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/**
  55 * is_zero_ether_addr - Determine if give Ethernet address is all zeros.
  56 * @addr: Pointer to a six-byte array containing the Ethernet address
  57 *
  58 * Return true if the address is all zeroes.
  59 */
  60static inline bool is_zero_ether_addr(const u8 *addr)
  61{
  62        return !(addr[0] | addr[1] | addr[2] | addr[3] | addr[4] | addr[5]);
  63}
  64
  65/**
  66 * is_multicast_ether_addr - Determine if the Ethernet address is a multicast.
  67 * @addr: Pointer to a six-byte array containing the Ethernet address
  68 *
  69 * Return true if the address is a multicast address.
  70 * By definition the broadcast address is also a multicast address.
  71 */
  72static inline bool is_multicast_ether_addr(const u8 *addr)
  73{
  74        return 0x01 & addr[0];
  75}
  76
  77/**
  78 * is_local_ether_addr - Determine if the Ethernet address is locally-assigned one (IEEE 802).
  79 * @addr: Pointer to a six-byte array containing the Ethernet address
  80 *
  81 * Return true if the address is a local address.
  82 */
  83static inline bool is_local_ether_addr(const u8 *addr)
  84{
  85        return 0x02 & addr[0];
  86}
  87
  88/**
  89 * is_broadcast_ether_addr - Determine if the Ethernet address is broadcast
  90 * @addr: Pointer to a six-byte array containing the Ethernet address
  91 *
  92 * Return true if the address is the broadcast address.
  93 */
  94static inline bool is_broadcast_ether_addr(const u8 *addr)
  95{
  96        return (addr[0] & addr[1] & addr[2] & addr[3] & addr[4] & addr[5]) == 0xff;
  97}
  98
  99/**
 100 * is_unicast_ether_addr - Determine if the Ethernet address is unicast
 101 * @addr: Pointer to a six-byte array containing the Ethernet address
 102 *
 103 * Return true if the address is a unicast address.
 104 */
 105static inline bool is_unicast_ether_addr(const u8 *addr)
 106{
 107        return !is_multicast_ether_addr(addr);
 108}
 109
 110/**
 111 * is_valid_ether_addr - Determine if the given Ethernet address is valid
 112 * @addr: Pointer to a six-byte array containing the Ethernet address
 113 *
 114 * Check that the Ethernet address (MAC) is not 00:00:00:00:00:00, is not
 115 * a multicast address, and is not FF:FF:FF:FF:FF:FF.
 116 *
 117 * Return true if the address is valid.
 118 */
 119static inline bool is_valid_ether_addr(const u8 *addr)
 120{
 121        /* FF:FF:FF:FF:FF:FF is a multicast address so we don't need to
 122         * explicitly check for it here. */
 123        return !is_multicast_ether_addr(addr) && !is_zero_ether_addr(addr);
 124}
 125
 126/**
 127 * eth_random_addr - Generate software assigned random Ethernet address
 128 * @addr: Pointer to a six-byte array containing the Ethernet address
 129 *
 130 * Generate a random Ethernet address (MAC) that is not multicast
 131 * and has the local assigned bit set.
 132 */
 133static inline void eth_random_addr(u8 *addr)
 134{
 135        get_random_bytes(addr, ETH_ALEN);
 136        addr[0] &= 0xfe;        /* clear multicast bit */
 137        addr[0] |= 0x02;        /* set local assignment bit (IEEE802) */
 138}
 139
 140#define random_ether_addr(addr) eth_random_addr(addr)
 141
 142/**
 143 * eth_broadcast_addr - Assign broadcast address
 144 * @addr: Pointer to a six-byte array containing the Ethernet address
 145 *
 146 * Assign the broadcast address to the given address array.
 147 */
 148static inline void eth_broadcast_addr(u8 *addr)
 149{
 150        memset(addr, 0xff, ETH_ALEN);
 151}
 152
 153/**
 154 * eth_hw_addr_random - Generate software assigned random Ethernet and
 155 * set device flag
 156 * @dev: pointer to net_device structure
 157 *
 158 * Generate a random Ethernet address (MAC) to be used by a net device
 159 * and set addr_assign_type so the state can be read by sysfs and be
 160 * used by userspace.
 161 */
 162static inline void eth_hw_addr_random(struct net_device *dev)
 163{
 164        dev->addr_assign_type |= NET_ADDR_RANDOM;
 165        eth_random_addr(dev->dev_addr);
 166}
 167
 168/**
 169 * compare_ether_addr - Compare two Ethernet addresses
 170 * @addr1: Pointer to a six-byte array containing the Ethernet address
 171 * @addr2: Pointer other six-byte array containing the Ethernet address
 172 *
 173 * Compare two Ethernet addresses, returns 0 if equal, non-zero otherwise.
 174 * Unlike memcmp(), it doesn't return a value suitable for sorting.
 175 */
 176static inline unsigned compare_ether_addr(const u8 *addr1, const u8 *addr2)
 177{
 178        const u16 *a = (const u16 *) addr1;
 179        const u16 *b = (const u16 *) addr2;
 180
 181        BUILD_BUG_ON(ETH_ALEN != 6);
 182        return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | (a[2] ^ b[2])) != 0;
 183}
 184
 185/**
 186 * ether_addr_equal - Compare two Ethernet addresses
 187 * @addr1: Pointer to a six-byte array containing the Ethernet address
 188 * @addr2: Pointer other six-byte array containing the Ethernet address
 189 *
 190 * Compare two Ethernet addresses, returns true if equal
 191 */
 192static inline bool ether_addr_equal(const u8 *addr1, const u8 *addr2)
 193{
 194        return !compare_ether_addr(addr1, addr2);
 195}
 196
 197static inline unsigned long zap_last_2bytes(unsigned long value)
 198{
 199#ifdef __BIG_ENDIAN
 200        return value >> 16;
 201#else
 202        return value << 16;
 203#endif
 204}
 205
 206/**
 207 * ether_addr_equal_64bits - Compare two Ethernet addresses
 208 * @addr1: Pointer to an array of 8 bytes
 209 * @addr2: Pointer to an other array of 8 bytes
 210 *
 211 * Compare two Ethernet addresses, returns true if equal, false otherwise.
 212 *
 213 * The function doesn't need any conditional branches and possibly uses
 214 * word memory accesses on CPU allowing cheap unaligned memory reads.
 215 * arrays = { byte1, byte2, byte3, byte4, byte5, byte6, pad1, pad2 }
 216 *
 217 * Please note that alignment of addr1 & addr2 are only guaranteed to be 16 bits.
 218 */
 219
 220static inline bool ether_addr_equal_64bits(const u8 addr1[6+2],
 221                                           const u8 addr2[6+2])
 222{
 223#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
 224        unsigned long fold = ((*(unsigned long *)addr1) ^
 225                              (*(unsigned long *)addr2));
 226
 227        if (sizeof(fold) == 8)
 228                return zap_last_2bytes(fold) == 0;
 229
 230        fold |= zap_last_2bytes((*(unsigned long *)(addr1 + 4)) ^
 231                                (*(unsigned long *)(addr2 + 4)));
 232        return fold == 0;
 233#else
 234        return ether_addr_equal(addr1, addr2);
 235#endif
 236}
 237
 238/**
 239 * is_etherdev_addr - Tell if given Ethernet address belongs to the device.
 240 * @dev: Pointer to a device structure
 241 * @addr: Pointer to a six-byte array containing the Ethernet address
 242 *
 243 * Compare passed address with all addresses of the device. Return true if the
 244 * address if one of the device addresses.
 245 *
 246 * Note that this function calls ether_addr_equal_64bits() so take care of
 247 * the right padding.
 248 */
 249static inline bool is_etherdev_addr(const struct net_device *dev,
 250                                    const u8 addr[6 + 2])
 251{
 252        struct netdev_hw_addr *ha;
 253        bool res = false;
 254
 255        rcu_read_lock();
 256        for_each_dev_addr(dev, ha) {
 257                res = ether_addr_equal_64bits(addr, ha->addr);
 258                if (res)
 259                        break;
 260        }
 261        rcu_read_unlock();
 262        return res;
 263}
 264#endif  /* __KERNEL__ */
 265
 266/**
 267 * compare_ether_header - Compare two Ethernet headers
 268 * @a: Pointer to Ethernet header
 269 * @b: Pointer to Ethernet header
 270 *
 271 * Compare two Ethernet headers, returns 0 if equal.
 272 * This assumes that the network header (i.e., IP header) is 4-byte
 273 * aligned OR the platform can handle unaligned access.  This is the
 274 * case for all packets coming into netif_receive_skb or similar
 275 * entry points.
 276 */
 277
 278static inline unsigned long compare_ether_header(const void *a, const void *b)
 279{
 280#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
 281        unsigned long fold;
 282
 283        /*
 284         * We want to compare 14 bytes:
 285         *  [a0 ... a13] ^ [b0 ... b13]
 286         * Use two long XOR, ORed together, with an overlap of two bytes.
 287         *  [a0  a1  a2  a3  a4  a5  a6  a7 ] ^ [b0  b1  b2  b3  b4  b5  b6  b7 ] |
 288         *  [a6  a7  a8  a9  a10 a11 a12 a13] ^ [b6  b7  b8  b9  b10 b11 b12 b13]
 289         * This means the [a6 a7] ^ [b6 b7] part is done two times.
 290        */
 291        fold = *(unsigned long *)a ^ *(unsigned long *)b;
 292        fold |= *(unsigned long *)(a + 6) ^ *(unsigned long *)(b + 6);
 293        return fold;
 294#else
 295        u32 *a32 = (u32 *)((u8 *)a + 2);
 296        u32 *b32 = (u32 *)((u8 *)b + 2);
 297
 298        return (*(u16 *)a ^ *(u16 *)b) | (a32[0] ^ b32[0]) |
 299               (a32[1] ^ b32[1]) | (a32[2] ^ b32[2]);
 300#endif
 301}
 302
 303#endif  /* _LINUX_ETHERDEVICE_H */
 304
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