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_prepare_mac_addr_change(struct net_device *dev, void *p);
  44extern void eth_commit_mac_addr_change(struct net_device *dev, void *p);
  45extern int eth_mac_addr(struct net_device *dev, void *p);
  46extern int eth_change_mtu(struct net_device *dev, int new_mtu);
  47extern int eth_validate_addr(struct net_device *dev);
  48
  49
  50
  51extern struct net_device *alloc_etherdev_mqs(int sizeof_priv, unsigned int txqs,
  52                                            unsigned int rxqs);
  53#define alloc_etherdev(sizeof_priv) alloc_etherdev_mq(sizeof_priv, 1)
  54#define alloc_etherdev_mq(sizeof_priv, count) alloc_etherdev_mqs(sizeof_priv, count, count)
  55
  56/* Reserved Ethernet Addresses per IEEE 802.1Q */
  57static const u8 eth_reserved_addr_base[ETH_ALEN] __aligned(2) =
  58{ 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 };
  59
  60/**
  61 * is_link_local_ether_addr - Determine if given Ethernet address is link-local
  62 * @addr: Pointer to a six-byte array containing the Ethernet address
  63 *
  64 * Return true if address is link local reserved addr (01:80:c2:00:00:0X) per
  65 * IEEE 802.1Q 8.6.3 Frame filtering.
  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        return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | ((a[2] ^ b[2]) & m)) == 0;
  74}
  75
  76/**
  77 * is_zero_ether_addr - Determine if give Ethernet address is all zeros.
  78 * @addr: Pointer to a six-byte array containing the Ethernet address
  79 *
  80 * Return true if the address is all zeroes.
  81 */
  82static inline bool is_zero_ether_addr(const u8 *addr)
  83{
  84        return !(addr[0] | addr[1] | addr[2] | addr[3] | addr[4] | addr[5]);
  85}
  86
  87/**
  88 * is_multicast_ether_addr - Determine if the Ethernet address is a multicast.
  89 * @addr: Pointer to a six-byte array containing the Ethernet address
  90 *
  91 * Return true if the address is a multicast address.
  92 * By definition the broadcast address is also a multicast address.
  93 */
  94static inline bool is_multicast_ether_addr(const u8 *addr)
  95{
  96        return 0x01 & addr[0];
  97}
  98
  99/**
 100 * is_local_ether_addr - Determine if the Ethernet address is locally-assigned one (IEEE 802).
 101 * @addr: Pointer to a six-byte array containing the Ethernet address
 102 *
 103 * Return true if the address is a local address.
 104 */
 105static inline bool is_local_ether_addr(const u8 *addr)
 106{
 107        return 0x02 & addr[0];
 108}
 109
 110/**
 111 * is_broadcast_ether_addr - Determine if the Ethernet address is broadcast
 112 * @addr: Pointer to a six-byte array containing the Ethernet address
 113 *
 114 * Return true if the address is the broadcast address.
 115 */
 116static inline bool is_broadcast_ether_addr(const u8 *addr)
 117{
 118        return (addr[0] & addr[1] & addr[2] & addr[3] & addr[4] & addr[5]) == 0xff;
 119}
 120
 121/**
 122 * is_unicast_ether_addr - Determine if the Ethernet address is unicast
 123 * @addr: Pointer to a six-byte array containing the Ethernet address
 124 *
 125 * Return true if the address is a unicast address.
 126 */
 127static inline bool is_unicast_ether_addr(const u8 *addr)
 128{
 129        return !is_multicast_ether_addr(addr);
 130}
 131
 132/**
 133 * is_valid_ether_addr - Determine if the given Ethernet address is valid
 134 * @addr: Pointer to a six-byte array containing the Ethernet address
 135 *
 136 * Check that the Ethernet address (MAC) is not 00:00:00:00:00:00, is not
 137 * a multicast address, and is not FF:FF:FF:FF:FF:FF.
 138 *
 139 * Return true if the address is valid.
 140 */
 141static inline bool is_valid_ether_addr(const u8 *addr)
 142{
 143        /* FF:FF:FF:FF:FF:FF is a multicast address so we don't need to
 144         * explicitly check for it here. */
 145        return !is_multicast_ether_addr(addr) && !is_zero_ether_addr(addr);
 146}
 147
 148/**
 149 * eth_random_addr - Generate software assigned random Ethernet address
 150 * @addr: Pointer to a six-byte array containing the Ethernet address
 151 *
 152 * Generate a random Ethernet address (MAC) that is not multicast
 153 * and has the local assigned bit set.
 154 */
 155static inline void eth_random_addr(u8 *addr)
 156{
 157        get_random_bytes(addr, ETH_ALEN);
 158        addr[0] &= 0xfe;        /* clear multicast bit */
 159        addr[0] |= 0x02;        /* set local assignment bit (IEEE802) */
 160}
 161
 162#define random_ether_addr(addr) eth_random_addr(addr)
 163
 164/**
 165 * eth_broadcast_addr - Assign broadcast address
 166 * @addr: Pointer to a six-byte array containing the Ethernet address
 167 *
 168 * Assign the broadcast address to the given address array.
 169 */
 170static inline void eth_broadcast_addr(u8 *addr)
 171{
 172        memset(addr, 0xff, ETH_ALEN);
 173}
 174
 175/**
 176 * eth_zero_addr - Assign zero address
 177 * @addr: Pointer to a six-byte array containing the Ethernet address
 178 *
 179 * Assign the zero address to the given address array.
 180 */
 181static inline void eth_zero_addr(u8 *addr)
 182{
 183        memset(addr, 0x00, ETH_ALEN);
 184}
 185
 186/**
 187 * eth_hw_addr_random - Generate software assigned random Ethernet and
 188 * set device flag
 189 * @dev: pointer to net_device structure
 190 *
 191 * Generate a random Ethernet address (MAC) to be used by a net device
 192 * and set addr_assign_type so the state can be read by sysfs and be
 193 * used by userspace.
 194 */
 195static inline void eth_hw_addr_random(struct net_device *dev)
 196{
 197        dev->addr_assign_type = NET_ADDR_RANDOM;
 198        eth_random_addr(dev->dev_addr);
 199}
 200
 201/**
 202 * compare_ether_addr - Compare two Ethernet addresses
 203 * @addr1: Pointer to a six-byte array containing the Ethernet address
 204 * @addr2: Pointer other six-byte array containing the Ethernet address
 205 *
 206 * Compare two Ethernet addresses, returns 0 if equal, non-zero otherwise.
 207 * Unlike memcmp(), it doesn't return a value suitable for sorting.
 208 */
 209static inline unsigned compare_ether_addr(const u8 *addr1, const u8 *addr2)
 210{
 211        const u16 *a = (const u16 *) addr1;
 212        const u16 *b = (const u16 *) addr2;
 213
 214        BUILD_BUG_ON(ETH_ALEN != 6);
 215        return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | (a[2] ^ b[2])) != 0;
 216}
 217
 218/**
 219 * ether_addr_equal - Compare two Ethernet addresses
 220 * @addr1: Pointer to a six-byte array containing the Ethernet address
 221 * @addr2: Pointer other six-byte array containing the Ethernet address
 222 *
 223 * Compare two Ethernet addresses, returns true if equal
 224 */
 225static inline bool ether_addr_equal(const u8 *addr1, const u8 *addr2)
 226{
 227        return !compare_ether_addr(addr1, addr2);
 228}
 229
 230static inline unsigned long zap_last_2bytes(unsigned long value)
 231{
 232#ifdef __BIG_ENDIAN
 233        return value >> 16;
 234#else
 235        return value << 16;
 236#endif
 237}
 238
 239/**
 240 * ether_addr_equal_64bits - Compare two Ethernet addresses
 241 * @addr1: Pointer to an array of 8 bytes
 242 * @addr2: Pointer to an other array of 8 bytes
 243 *
 244 * Compare two Ethernet addresses, returns true if equal, false otherwise.
 245 *
 246 * The function doesn't need any conditional branches and possibly uses
 247 * word memory accesses on CPU allowing cheap unaligned memory reads.
 248 * arrays = { byte1, byte2, byte3, byte4, byte5, byte6, pad1, pad2 }
 249 *
 250 * Please note that alignment of addr1 & addr2 are only guaranteed to be 16 bits.
 251 */
 252
 253static inline bool ether_addr_equal_64bits(const u8 addr1[6+2],
 254                                           const u8 addr2[6+2])
 255{
 256#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
 257        unsigned long fold = ((*(unsigned long *)addr1) ^
 258                              (*(unsigned long *)addr2));
 259
 260        if (sizeof(fold) == 8)
 261                return zap_last_2bytes(fold) == 0;
 262
 263        fold |= zap_last_2bytes((*(unsigned long *)(addr1 + 4)) ^
 264                                (*(unsigned long *)(addr2 + 4)));
 265        return fold == 0;
 266#else
 267        return ether_addr_equal(addr1, addr2);
 268#endif
 269}
 270
 271/**
 272 * is_etherdev_addr - Tell if given Ethernet address belongs to the device.
 273 * @dev: Pointer to a device structure
 274 * @addr: Pointer to a six-byte array containing the Ethernet address
 275 *
 276 * Compare passed address with all addresses of the device. Return true if the
 277 * address if one of the device addresses.
 278 *
 279 * Note that this function calls ether_addr_equal_64bits() so take care of
 280 * the right padding.
 281 */
 282static inline bool is_etherdev_addr(const struct net_device *dev,
 283                                    const u8 addr[6 + 2])
 284{
 285        struct netdev_hw_addr *ha;
 286        bool res = false;
 287
 288        rcu_read_lock();
 289        for_each_dev_addr(dev, ha) {
 290                res = ether_addr_equal_64bits(addr, ha->addr);
 291                if (res)
 292                        break;
 293        }
 294        rcu_read_unlock();
 295        return res;
 296}
 297#endif  /* __KERNEL__ */
 298
 299/**
 300 * compare_ether_header - Compare two Ethernet headers
 301 * @a: Pointer to Ethernet header
 302 * @b: Pointer to Ethernet header
 303 *
 304 * Compare two Ethernet headers, returns 0 if equal.
 305 * This assumes that the network header (i.e., IP header) is 4-byte
 306 * aligned OR the platform can handle unaligned access.  This is the
 307 * case for all packets coming into netif_receive_skb or similar
 308 * entry points.
 309 */
 310
 311static inline unsigned long compare_ether_header(const void *a, const void *b)
 312{
 313#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
 314        unsigned long fold;
 315
 316        /*
 317         * We want to compare 14 bytes:
 318         *  [a0 ... a13] ^ [b0 ... b13]
 319         * Use two long XOR, ORed together, with an overlap of two bytes.
 320         *  [a0  a1  a2  a3  a4  a5  a6  a7 ] ^ [b0  b1  b2  b3  b4  b5  b6  b7 ] |
 321         *  [a6  a7  a8  a9  a10 a11 a12 a13] ^ [b6  b7  b8  b9  b10 b11 b12 b13]
 322         * This means the [a6 a7] ^ [b6 b7] part is done two times.
 323        */
 324        fold = *(unsigned long *)a ^ *(unsigned long *)b;
 325        fold |= *(unsigned long *)(a + 6) ^ *(unsigned long *)(b + 6);
 326        return fold;
 327#else
 328        u32 *a32 = (u32 *)((u8 *)a + 2);
 329        u32 *b32 = (u32 *)((u8 *)b + 2);
 330
 331        return (*(u16 *)a ^ *(u16 *)b) | (a32[0] ^ b32[0]) |
 332               (a32[1] ^ b32[1]) | (a32[2] ^ b32[2]);
 333#endif
 334}
 335
 336#endif  /* _LINUX_ETHERDEVICE_H */
 337
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