ethernet.h revision 55205 
1/*
2 * Fundamental constants relating to ethernet.
3 *
4 * $FreeBSD: head/sys/net/ethernet.h 55205 1999-12-29 04:46:21Z peter $
5 *
6 */
7
8#ifndef _NET_ETHERNET_H_
9#define _NET_ETHERNET_H_
10
11/*
12 * The number of bytes in an ethernet (MAC) address.
13 */
14#define	ETHER_ADDR_LEN		6
15
16/*
17 * The number of bytes in the type field.
18 */
19#define	ETHER_TYPE_LEN		2
20
21/*
22 * The number of bytes in the trailing CRC field.
23 */
24#define	ETHER_CRC_LEN		4
25
26/*
27 * The length of the combined header.
28 */
29#define	ETHER_HDR_LEN		(ETHER_ADDR_LEN*2+ETHER_TYPE_LEN)
30
31/*
32 * The minimum packet length.
33 */
34#define	ETHER_MIN_LEN		64
35
36/*
37 * The maximum packet length.
38 */
39#define	ETHER_MAX_LEN		1518
40
41/*
42 * A macro to validate a length with
43 */
44#define	ETHER_IS_VALID_LEN(foo)	\
45	((foo) >= ETHER_MIN_LEN && (foo) <= ETHER_MAX_LEN)
46
47/*
48 * Structure of a 10Mb/s Ethernet header.
49 */
50struct	ether_header {
51	u_char	ether_dhost[ETHER_ADDR_LEN];
52	u_char	ether_shost[ETHER_ADDR_LEN];
53	u_short	ether_type;
54};
55
56/*
57 * Structure of a 48-bit Ethernet address.
58 */
59struct	ether_addr {
60	u_char octet[ETHER_ADDR_LEN];
61};
62
63#define	ETHERTYPE_PUP		0x0200	/* PUP protocol */
64#define	ETHERTYPE_IP		0x0800	/* IP protocol */
65#define	ETHERTYPE_ARP		0x0806	/* Addr. resolution protocol */
66#define	ETHERTYPE_REVARP	0x8035	/* reverse Addr. resolution protocol */
67#define	ETHERTYPE_VLAN		0x8100	/* IEEE 802.1Q VLAN tagging */
68#define	ETHERTYPE_IPV6		0x86dd	/* IPv6 */
69#define	ETHERTYPE_LOOPBACK	0x9000	/* used to test interfaces */
70/* XXX - add more useful types here */
71
72/*
73 * The ETHERTYPE_NTRAILER packet types starting at ETHERTYPE_TRAIL have
74 * (type-ETHERTYPE_TRAIL)*512 bytes of data followed
75 * by an ETHER type (as given above) and then the (variable-length) header.
76 */
77#define	ETHERTYPE_TRAIL		0x1000		/* Trailer packet */
78#define	ETHERTYPE_NTRAILER	16
79
80#define	ETHERMTU	(ETHER_MAX_LEN-ETHER_HDR_LEN-ETHER_CRC_LEN)
81#define	ETHERMIN	(ETHER_MIN_LEN-ETHER_HDR_LEN-ETHER_CRC_LEN)
82
83#ifndef _KERNEL
84#include <sys/cdefs.h>
85
86/*
87 * Ethernet address conversion/parsing routines.
88 */
89__BEGIN_DECLS
90struct	ether_addr *ether_aton __P((char *));
91int	ether_hostton __P((char *, struct ether_addr *));
92int	ether_line __P((char *, struct ether_addr *, char *));
93char 	*ether_ntoa __P((struct ether_addr *));
94int	ether_ntohost __P((char *, struct ether_addr *));
95__END_DECLS
96#endif
97
98#endif /* !_NET_ETHERNET_H_ */
99