/*	@(#)if_ether.h	13.1 (RC International) 91/02/02	*/
/*
 * Copyright (c) 1982, 1986 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that this notice is preserved and that due credit is given
 * to the University of California at Berkeley. The name of the University
 * may not be used to endorse or promote products derived from this
 * software without specific prior written permission. This software
 * is provided ``as is'' without express or implied warranty.
 *
 *	@(-)if_ether.h	7.2 (Berkeley) 12/7/87
 */

/*
 *  Ethernet address
 */
struct	etheraddr {
	u_char			bytes[6];	/* 48 bits */
};

/*
 * Structure of a 10Mb/s Ethernet header.
 */
struct	ether_header {
	u_char	ether_dhost[6];
	u_char	ether_shost[6];
	u_short	ether_type;
};

#define	ETHERTYPE_PUP	0x0200		/* PUP protocol */
#define	ETHERTYPE_IP	0x0800		/* IP protocol */
#define ETHERTYPE_ARP	0x0806		/* Addr. resolution protocol */

#define	ETHERMTU	1500		/* max transmission size */
#define	ETHERMIN	(60-14)		/* min transmission size */

/*
 * The ETHERTYPE_NTRAILER packet types starting at ETHERTYPE_TRAIL have
 * (type-ETHERTYPE_TRAIL)*512 bytes of data followed
 * by an ETHER type (as given above) and then the (variable-length) header.
 *
 * ARP trailer negotiation.  Trailer protocol is not IP specific,
 * but ARP request/response use IP addresses.
 */
#define	ETHERTYPE_NTRAILER	16
#define	ETHERTYPE_TRAIL		0x1000		/* Trailer packet */
#define ETHERTYPE_IPTRAILERS	ETHERTYPE_TRAIL	/* IP type trailer packets */

/*
 * Ethernet Address Resolution Protocol.
 *
 * See RFC 826 for protocol description.  Structure below is adapted
 * to resolving internet addresses.  Field names used correspond to 
 * RFC 826.
 */
struct	ether_arp {
	struct	arphdr ea_hdr;	/* fixed-size header */
	u_char	arp_sha[6];	/* sender hardware address */
	u_char	arp_spa[4];	/* sender protocol address */
	u_char	arp_tha[6];	/* target hardware address */
	u_char	arp_tpa[4];	/* target protocol address */
};
#define	arp_hrd	ea_hdr.ar_hrd
#define	arp_pro	ea_hdr.ar_pro
#define	arp_hln	ea_hdr.ar_hln
#define	arp_pln	ea_hdr.ar_pln
#define	arp_op	ea_hdr.ar_op


/*
 * Structure shared between the ethernet driver modules and
 * the address resolution code.  For example, each ec_softc or il_softc
 * begins with this structure.
 */
struct	arpcom {
	struct 	ifnet ac_if;		/* network-visible interface */
	u_char	ac_enaddr[6];		/* ethernet hardware address */
	struct in_addr ac_ipaddr;	/* copy of ip address- XXX */
};

/*
 * Internet to ethernet address resolution table.
 */
struct	arptab {
	struct	in_addr at_iaddr;	/* internet address */
	u_char	at_enaddr[6];		/* ethernet address */
	u_char	at_timer;		/* minutes since last reference */
	u_char	at_flags;		/* flags */
	struct	mbuf *at_hold;		/* last packet until resolved/timeout */
};

/*
 * Timer related values
 */
#define	ARPT_AGE	(60*1)	/* aging timer, 1 min. */
#define	ARPT_KILLC	20	/* kill completed entry in 20 mins. */
#define	ARPT_KILLI	3	/* kill incomplete entry in 3 minutes */

/*
 * Table access routines
 */
#define	ARPTAB_HASH(a) \
	((u_long)(a) % ARPTAB_NB)

#define	ARPTAB_LOOK(at,addr) { \
	register n; \
	at = &arptab[ARPTAB_HASH(addr) * ARPTAB_BSIZ]; \
	for (n = 0 ; n < ARPTAB_BSIZ ; n++,at++) \
		if (at->at_iaddr.s_addr == addr) \
			break; \
	if (n >= ARPTAB_BSIZ) \
		at = 0; \
}

#ifdef GATEWAY
#define	ARPTAB_BSIZ	16		/* bucket size */
#define	ARPTAB_NB	37		/* number of buckets */
#else
#define	ARPTAB_BSIZ	9		/* bucket size */
#define	ARPTAB_NB	19		/* number of buckets */
#endif
#define	ARPTAB_SIZE	(ARPTAB_BSIZ * ARPTAB_NB)