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 *      WARNING: This move may well be temporary. This file will get merged with others RSN.
  22 *
  23 */
  24#ifndef _LINUX_ETHERDEVICE_H
  25#define _LINUX_ETHERDEVICE_H
  26
  27#include <linux/if_ether.h>
  28#include <linux/netdevice.h>
  29#include <linux/random.h>
  30#include <asm/unaligned.h>
  31
  32#ifdef __KERNEL__
  33extern __be16           eth_type_trans(struct sk_buff *skb, struct net_device *dev);
  34extern const struct header_ops eth_header_ops;
  35
  36extern int eth_header(struct sk_buff *skb, struct net_device *dev,
  37                      unsigned short type,
  38                      const void *daddr, const void *saddr, unsigned len);
  39extern int eth_rebuild_header(struct sk_buff *skb);
  40extern int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr);
  41extern int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh);
  42extern void eth_header_cache_update(struct hh_cache *hh,
  43                                    const struct net_device *dev,
  44                                    const unsigned char *haddr);
  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_mq(int sizeof_priv, unsigned int queue_count);
  52#define alloc_etherdev(sizeof_priv) alloc_etherdev_mq(sizeof_priv, 1)
  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 int 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 int 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 int 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 int 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_valid_ether_addr - Determine if the given Ethernet address is valid
 101 * @addr: Pointer to a six-byte array containing the Ethernet address
 102 *
 103 * Check that the Ethernet address (MAC) is not 00:00:00:00:00:00, is not
 104 * a multicast address, and is not FF:FF:FF:FF:FF:FF.
 105 *
 106 * Return true if the address is valid.
 107 */
 108static inline int is_valid_ether_addr(const u8 *addr)
 109{
 110        /* FF:FF:FF:FF:FF:FF is a multicast address so we don't need to
 111         * explicitly check for it here. */
 112        return !is_multicast_ether_addr(addr) && !is_zero_ether_addr(addr);
 113}
 114
 115/**
 116 * random_ether_addr - Generate software assigned random Ethernet address
 117 * @addr: Pointer to a six-byte array containing the Ethernet address
 118 *
 119 * Generate a random Ethernet address (MAC) that is not multicast
 120 * and has the local assigned bit set.
 121 */
 122static inline void random_ether_addr(u8 *addr)
 123{
 124        get_random_bytes (addr, ETH_ALEN);
 125        addr [0] &= 0xfe;       /* clear multicast bit */
 126        addr [0] |= 0x02;       /* set local assignment bit (IEEE802) */
 127}
 128
 129/**
 130 * dev_hw_addr_random - Create random MAC and set device flag
 131 * @dev: pointer to net_device structure
 132 * @hwaddr: Pointer to a six-byte array containing the Ethernet address
 133 *
 134 * Generate random MAC to be used by a device and set addr_assign_type
 135 * so the state can be read by sysfs and be used by udev.
 136 */
 137static inline void dev_hw_addr_random(struct net_device *dev, u8 *hwaddr)
 138{
 139        dev->addr_assign_type |= NET_ADDR_RANDOM;
 140        random_ether_addr(hwaddr);
 141}
 142
 143/**
 144 * compare_ether_addr - Compare two Ethernet addresses
 145 * @addr1: Pointer to a six-byte array containing the Ethernet address
 146 * @addr2: Pointer other six-byte array containing the Ethernet address
 147 *
 148 * Compare two ethernet addresses, returns 0 if equal
 149 */
 150static inline unsigned compare_ether_addr(const u8 *addr1, const u8 *addr2)
 151{
 152        const u16 *a = (const u16 *) addr1;
 153        const u16 *b = (const u16 *) addr2;
 154
 155        BUILD_BUG_ON(ETH_ALEN != 6);
 156        return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | (a[2] ^ b[2])) != 0;
 157}
 158
 159static inline unsigned long zap_last_2bytes(unsigned long value)
 160{
 161#ifdef __BIG_ENDIAN
 162        return value >> 16;
 163#else
 164        return value << 16;
 165#endif
 166}
 167
 168/**
 169 * compare_ether_addr_64bits - Compare two Ethernet addresses
 170 * @addr1: Pointer to an array of 8 bytes
 171 * @addr2: Pointer to an other array of 8 bytes
 172 *
 173 * Compare two ethernet addresses, returns 0 if equal.
 174 * Same result than "memcmp(addr1, addr2, ETH_ALEN)" but without conditional
 175 * branches, and possibly long word memory accesses on CPU allowing cheap
 176 * unaligned memory reads.
 177 * arrays = { byte1, byte2, byte3, byte4, byte6, byte7, pad1, pad2}
 178 *
 179 * Please note that alignment of addr1 & addr2 is only guaranted to be 16 bits.
 180 */
 181
 182static inline unsigned compare_ether_addr_64bits(const u8 addr1[6+2],
 183                                                 const u8 addr2[6+2])
 184{
 185#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
 186        unsigned long fold = ((*(unsigned long *)addr1) ^
 187                              (*(unsigned long *)addr2));
 188
 189        if (sizeof(fold) == 8)
 190                return zap_last_2bytes(fold) != 0;
 191
 192        fold |= zap_last_2bytes((*(unsigned long *)(addr1 + 4)) ^
 193                                (*(unsigned long *)(addr2 + 4)));
 194        return fold != 0;
 195#else
 196        return compare_ether_addr(addr1, addr2);
 197#endif
 198}
 199
 200/**
 201 * is_etherdev_addr - Tell if given Ethernet address belongs to the device.
 202 * @dev: Pointer to a device structure
 203 * @addr: Pointer to a six-byte array containing the Ethernet address
 204 *
 205 * Compare passed address with all addresses of the device. Return true if the
 206 * address if one of the device addresses.
 207 *
 208 * Note that this function calls compare_ether_addr_64bits() so take care of
 209 * the right padding.
 210 */
 211static inline bool is_etherdev_addr(const struct net_device *dev,
 212                                    const u8 addr[6 + 2])
 213{
 214        struct netdev_hw_addr *ha;
 215        int res = 1;
 216
 217        rcu_read_lock();
 218        for_each_dev_addr(dev, ha) {
 219                res = compare_ether_addr_64bits(addr, ha->addr);
 220                if (!res)
 221                        break;
 222        }
 223        rcu_read_unlock();
 224        return !res;
 225}
 226#endif  /* __KERNEL__ */
 227
 228/**
 229 * compare_ether_header - Compare two Ethernet headers
 230 * @a: Pointer to Ethernet header
 231 * @b: Pointer to Ethernet header
 232 *
 233 * Compare two ethernet headers, returns 0 if equal.
 234 * This assumes that the network header (i.e., IP header) is 4-byte
 235 * aligned OR the platform can handle unaligned access.  This is the
 236 * case for all packets coming into netif_receive_skb or similar
 237 * entry points.
 238 */
 239
 240static inline int compare_ether_header(const void *a, const void *b)
 241{
 242        u32 *a32 = (u32 *)((u8 *)a + 2);
 243        u32 *b32 = (u32 *)((u8 *)b + 2);
 244
 245        return (*(u16 *)a ^ *(u16 *)b) | (a32[0] ^ b32[0]) |
 246               (a32[1] ^ b32[1]) | (a32[2] ^ b32[2]);
 247}
 248
 249#endif  /* _LINUX_ETHERDEVICE_H */
 250
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