summaryrefslogtreecommitdiffstats
path: root/cpukit/libnetworking/net/ethernet.h
blob: 1f988d7b9e43a401759030c1b046a4e8d6425640 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
/*
 * Fundamental constants relating to ethernet.
 *
 * $Id$
 *
 */

#ifndef _NET_ETHERNET_H_
#define _NET_ETHERNET_H_

#include <netinet/in.h>

/*
 * The number of bytes in an ethernet (MAC) address.
 */
#define	ETHER_ADDR_LEN		6

/*
 * The number of bytes in the type field.
 */
#define	ETHER_TYPE_LEN		2

/*
 * The number of bytes in the trailing CRC field.
 */
#define	ETHER_CRC_LEN		4

/*
 * The length of the combined header.
 */
#define	ETHER_HDR_LEN		(ETHER_ADDR_LEN*2+ETHER_TYPE_LEN)

/*
 * The minimum packet length.
 */
#define	ETHER_MIN_LEN		64

/*
 * The maximum packet length.
 */
#define	ETHER_MAX_LEN		1518

/*
 * A macro to validate a length with
 */
#define	ETHER_IS_VALID_LEN(foo)	\
	((foo) >= ETHER_MIN_LEN && (foo) <= ETHER_MAX_LEN)

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

/*
 * Structure of a 48-bit Ethernet address.
 */
struct	ether_addr {
	u_char octet[ETHER_ADDR_LEN];
};

#endif