include/net/if_ether.h
/*	$NetBSD: if_ether.h,v 1.58 2010/05/19 20:41:59 christos Exp $	*/

/*
 * Copyright (c) 1982, 1986, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)if_ether.h	8.1 (Berkeley) 6/10/93
 */

#ifndef _NET_IF_ETHER_H_
#define _NET_IF_ETHER_H_

/*
 * Some basic Ethernet constants.
 */
#define	ETHER_ADDR_LEN	6	/* length of an Ethernet address */
#define	ETHER_TYPE_LEN	2	/* length of the Ethernet type field */
#define	ETHER_CRC_LEN	4	/* length of the Ethernet CRC */
#define	ETHER_HDR_LEN	((ETHER_ADDR_LEN * 2) + ETHER_TYPE_LEN)
#define	ETHER_MIN_LEN	64	/* minimum frame length, including CRC */
#define	ETHER_MAX_LEN	1518	/* maximum frame length, including CRC */
#define	ETHER_MAX_LEN_JUMBO 9018 /* maximum jumbo frame len, including CRC */

/*
 * Some Ethernet extensions.
 */
#define	ETHER_VLAN_ENCAP_LEN 4	/* length of 802.1Q VLAN encapsulation */
#define	ETHER_PPPOE_ENCAP_LEN 8	/* length of PPPoE encapsulation */

/*
 * Ethernet address - 6 octets
 * this is only used by the ethers(3) functions.
 */
struct ether_addr {
	uint8_t ether_addr_octet[ETHER_ADDR_LEN];
} __packed;

/*
 * Structure of a 10Mb/s Ethernet header.
 */
struct ether_header {
	uint8_t  ether_dhost[ETHER_ADDR_LEN];
	uint8_t  ether_shost[ETHER_ADDR_LEN];
	uint16_t ether_type;
} __packed;

#include <net/ethertypes.h>

#define	ETHER_IS_MULTICAST(addr) (*(addr) & 0x01) /* is address mcast/bcast? */
#define	ETHER_IS_LOCAL(addr) (*(addr) & 0x02) /* is address local? */

#define	ETHERMTU_JUMBO	(ETHER_MAX_LEN_JUMBO - ETHER_HDR_LEN - ETHER_CRC_LEN)
#define	ETHERMTU	(ETHER_MAX_LEN - ETHER_HDR_LEN - ETHER_CRC_LEN)
#define	ETHERMIN	(ETHER_MIN_LEN - ETHER_HDR_LEN - ETHER_CRC_LEN)

/*
 * Compute the maximum frame size based on ethertype (i.e. possible
 * encapsulation) and whether or not an FCS is present.
 */
#define	ETHER_MAX_FRAME(ifp, etype, hasfcs)				\
	((ifp)->if_mtu + ETHER_HDR_LEN +				\
	 ((hasfcs) ? ETHER_CRC_LEN : 0) +				\
	 (((etype) == ETHERTYPE_VLAN) ? ETHER_VLAN_ENCAP_LEN : 0) +	\
	 (((etype) == ETHERTYPE_PPPOE) ? ETHER_PPPOE_ENCAP_LEN : 0))

/*
 * Ethernet CRC32 polynomials (big- and little-endian verions).
 */
#define	ETHER_CRC_POLY_LE	0xedb88320
#define	ETHER_CRC_POLY_BE	0x04c11db6

/*
 * Prototype ethers(3) functions.
 */
#include <sys/cdefs.h>
__BEGIN_DECLS
char *	ether_ntoa(const struct ether_addr *);
struct ether_addr *
	ether_aton(const char *);
int	ether_ntohost(char *, const struct ether_addr *);
int	ether_hostton(const char *, struct ether_addr *);
int	ether_line(const char *, struct ether_addr *, char *);
__END_DECLS

#endif /* !_NET_IF_ETHER_H_ */
