tcpdump/ether.h
Guy Harris 08e40fdbd6 The last 2 bytes of an Ethernet header are the "length/type field".
Call it that, to indicate that it's not necessarily a type field.

While we're at it, get rid of references to "DEC/Intel/Xerox" and
"802.3" Ethernet headers in comments; since 802.3y, the 802.3 standard
supports both "DIX" frames, with a type field, and earlier 802.3 frames,
with a length field, so there's only one version of Ethernet, 802.3,
which supports frames with type fields and frames with length fields.
2015-12-16 21:04:13 -08:00

58 lines
2.3 KiB
C

/*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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 8.3 (Berkeley) 5/2/95
*/
#define ETHERMTU 1500
/*
* The number of bytes in an ethernet (MAC) address.
*/
#define ETHER_ADDR_LEN 6
/*
* Structure of an Ethernet header.
*/
struct ether_header {
uint8_t ether_dhost[ETHER_ADDR_LEN];
uint8_t ether_shost[ETHER_ADDR_LEN];
uint16_t ether_length_type;
};
/*
* Length of an Ethernet header; note that some compilers may pad
* "struct ether_header" to a multiple of 4 bytes, for example, so
* "sizeof (struct ether_header)" may not give the right answer.
*/
#define ETHER_HDRLEN 14