include/linux/etherdevice.h

/*
 * INET		An implementation of the TCP/IP protocol suite for the LINUX
 *		operating system.  NET  is implemented using the  BSD Socket
 *		interface as the means of communication with the user level.
 *
 *		Definitions for the Ethernet handlers.
 *
 * Version:	@(#)eth.h	1.0.4	05/13/93
 *
 * Authors:	Ross Biro
 *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 *
 *		Relocated to include/linux where it belongs by Alan Cox 
 *							<gw4pts@gw4pts.ampr.org>
 *
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 *
 *	WARNING: This move may well be temporary. This file will get merged with others RSN.
 *
 */
#ifndef _LINUX_ETHERDEVICE_H
#define _LINUX_ETHERDEVICE_H

#include <linux/if_ether.h>
#include <linux/netdevice.h>
#include <linux/random.h>

#ifdef __KERNEL__
extern int		eth_header(struct sk_buff *skb, struct net_device *dev,
				   unsigned short type, void *daddr,
				   void *saddr, unsigned len);
extern int		eth_rebuild_header(struct sk_buff *skb);
extern __be16		eth_type_trans(struct sk_buff *skb, struct net_device *dev);
extern void		eth_header_cache_update(struct hh_cache *hh, struct net_device *dev,
						unsigned char * haddr);
extern int		eth_header_cache(struct neighbour *neigh,
					 struct hh_cache *hh);

extern struct net_device *alloc_etherdev(int sizeof_priv);

/**
 * is_zero_ether_addr - Determine if give Ethernet address is all zeros.
 * @addr: Pointer to a six-byte array containing the Ethernet address
 *
 * Return true if the address is all zeroes.
 */
static inline int is_zero_ether_addr(const u8 *addr)
{
	return !(addr[0] | addr[1] | addr[2] | addr[3] | addr[4] | addr[5]);
}

/**
 * is_multicast_ether_addr - Determine if the Ethernet address is a multicast.
 * @addr: Pointer to a six-byte array containing the Ethernet address
 *
 * Return true if the address is a multicast address.
 * By definition the broadcast address is also a multicast address.
 */
static inline int is_multicast_ether_addr(const u8 *addr)
{
	return (0x01 & addr[0]);
}

/**
 * is_local_ether_addr - Determine if the Ethernet address is locally-assigned
 * one (IEEE 802).
 * @addr: Pointer to a six-byte array containing the Ethernet address
 *
 * Return true if the address is a local address.
 */
static inline int is_local_ether_addr(const u8 *addr)
{
	return (0x02 & addr[0]);
}

/**
 * is_broadcast_ether_addr - Determine if the Ethernet address is broadcast
 * @addr: Pointer to a six-byte array containing the Ethernet address
 *
 * Return true if the address is the broadcast address.
 */
static inline int is_broadcast_ether_addr(const u8 *addr)
{
	return (addr[0] & addr[1] & addr[2] & addr[3] & addr[4] & addr[5]) == 0xff;
}

/**
 * is_valid_ether_addr - Determine if the given Ethernet address is valid
 * @addr: Pointer to a six-byte array containing the Ethernet address
 *
 * Check that the Ethernet address (MAC) is not 00:00:00:00:00:00, is not
 * a multicast address, and is not FF:FF:FF:FF:FF:FF.
 *
 * Return true if the address is valid.
 */
static inline int is_valid_ether_addr(const u8 *addr)
{
	/* FF:FF:FF:FF:FF:FF is a multicast address so we don't need to
	 * explicitly check for it here. */
	return !is_multicast_ether_addr(addr) && !is_zero_ether_addr(addr);
}

/**
 * random_ether_addr - Generate software assigned random Ethernet address
 * @addr: Pointer to a six-byte array containing the Ethernet address
 *
 * Generate a random Ethernet address (MAC) that is not multicast
 * and has the local assigned bit set.
 */
static inline void random_ether_addr(u8 *addr)
{
	get_random_bytes (addr, ETH_ALEN);
	addr [0] &= 0xfe;	/* clear multicast bit */
	addr [0] |= 0x02;	/* set local assignment bit (IEEE802) */
}

/**
 * compare_ether_addr - Compare two Ethernet addresses
 * @addr1: Pointer to a six-byte array containing the Ethernet address
 * @addr2: Pointer other six-byte array containing the Ethernet address
 *
 * Compare two ethernet addresses, returns 0 if equal
 */
static inline unsigned compare_ether_addr(const u8 *addr1, const u8 *addr2)
{
	const u16 *a = (const u16 *) addr1;
	const u16 *b = (const u16 *) addr2;

	BUILD_BUG_ON(ETH_ALEN != 6);
	return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | (a[2] ^ b[2])) != 0;
}
#endif	/* __KERNEL__ */

#endif	/* _LINUX_ETHERDEVICE_H */