include/linux/etherdevice.h

   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__
  33 extern __be16           eth_type_trans(struct sk_buff *skb, struct net_device *dev);
  34 extern const struct header_ops eth_header_ops;
  35
  36 extern int eth_header(struct sk_buff *skb, struct net_device *dev,
  37                       unsigned short type,
  38                       const void *daddr, const void *saddr, unsigned len);
  39 extern int eth_rebuild_header(struct sk_buff *skb);
  40 extern int eth_header_parse(const struct sk_buff *skb, unsigned char *haddr);
  41 extern int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh);
  42 extern void eth_header_cache_update(struct hh_cache *hh,
  43                                     const struct net_device *dev,
  44                                     const unsigned char *haddr);
  45 extern int eth_mac_addr(struct net_device *dev, void *p);
  46 extern int eth_change_mtu(struct net_device *dev, int new_mtu);
  47 extern int eth_validate_addr(struct net_device *dev);
  48
  49
  50
  51 extern 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  */
  60 static 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  */
  72 static 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  */
  83 static 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  */
  94 static 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  */
 108 static 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  */
 122 static 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  */
 137 static 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  */
 150 static 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
 159 static 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
 182 static 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  */
 211 static 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
 240 static inline unsigned long compare_ether_header(const void *a, const void *b)
 241 {
 242 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
 243         unsigned long fold;
 244
 245         /*
 246          * We want to compare 14 bytes:
 247          *  [a0 ... a13] ^ [b0 ... b13]
 248          * Use two long XOR, ORed together, with an overlap of two bytes.
 249          *  [a0  a1  a2  a3  a4  a5  a6  a7 ] ^ [b0  b1  b2  b3  b4  b5  b6  b7 ] |
 250          *  [a6  a7  a8  a9  a10 a11 a12 a13] ^ [b6  b7  b8  b9  b10 b11 b12 b13]
 251          * This means the [a6 a7] ^ [b6 b7] part is done two times.
 252         */
 253         fold = *(unsigned long *)a ^ *(unsigned long *)b;
 254         fold |= *(unsigned long *)(a + 6) ^ *(unsigned long *)(b + 6);
 255         return fold;
 256 #else
 257         u32 *a32 = (u32 *)((u8 *)a + 2);
 258         u32 *b32 = (u32 *)((u8 *)b + 2);
 259
 260         return (*(u16 *)a ^ *(u16 *)b) | (a32[0] ^ b32[0]) |
 261                (a32[1] ^ b32[1]) | (a32[2] ^ b32[2]);
 262 #endif
 263 }
 264
 265 #endif  /* _LINUX_ETHERDEVICE_H */