4.3BSD-Reno/src/sys/vaxif/if_en.h

/*
 * Copyright (c) 1982, 1986 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution is only permitted until one year after the first shipment
 * of 4.4BSD by the Regents.  Otherwise, redistribution and use in source and
 * binary forms are permitted provided that: (1) source distributions retain
 * this entire copyright notice and comment, and (2) distributions including
 * binaries display the following acknowledgement:  This product includes
 * software developed by the University of California, Berkeley and its
 * contributors'' in the documentation or other materials provided with the
 * distribution and in all advertising materials mentioning features or use
 * of this software.  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 AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 *	@(#)if_en.h	7.3 (Berkeley) 6/28/90
 */

/*
 * Structure of a Ethernet header.
 */
struct	en_header {
	u_char	en_shost;
	u_char	en_dhost;
	u_short	en_type;
};

#define	ENTYPE_PUP	0x0200		/* PUP protocol */
#define	ENTYPE_IP	0x0201		/* IP protocol */

/*
 * The ENTYPE_NTRAILER packet types starting at
 * ENTYPE_TRAIL have (type-ENTYPE_TRAIL)*512 bytes
 * of data followed by an Ethernet type (as given above)
 * and then the (variable-length) header.
 */
#define	ENTYPE_TRAIL	0x1000		/* Trailer type */
#define	ENTYPE_NTRAILER	16

#define EN_BROADCAST	0		/* Hardware broadcast address */