1/*-
2 * Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from the Stanford/CMU enet packet filter,
6 * (net/enet.c) distributed as part of 4.3BSD, and code contributed
7 * to Berkeley by Steven McCanne and Van Jacobson both of Lawrence
8 * Berkeley Laboratory.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 *    may be used to endorse or promote products derived from this software
20 *    without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * @(#) Header: /tcpdump/master/tcpdump/sll.h,v 1.8 2008-05-30 01:37:41 guy Exp (LBL)
35 */
36
37/*
38 * For captures on Linux cooked sockets, we construct a fake header
39 * that includes:
40 *
41 *	a 2-byte "packet type" which is one of:
42 *
43 *		LINUX_SLL_HOST		packet was sent to us
44 *		LINUX_SLL_BROADCAST	packet was broadcast
45 *		LINUX_SLL_MULTICAST	packet was multicast
46 *		LINUX_SLL_OTHERHOST	packet was sent to somebody else
47 *		LINUX_SLL_OUTGOING	packet was sent *by* us;
48 *
49 *	a 2-byte Ethernet protocol field;
50 *
51 *	a 2-byte link-layer type;
52 *
53 *	a 2-byte link-layer address length;
54 *
55 *	an 8-byte source link-layer address, whose actual length is
56 *	specified by the previous value.
57 *
58 * All fields except for the link-layer address are in network byte order.
59 *
60 * DO NOT change the layout of this structure, or change any of the
61 * LINUX_SLL_ values below.  If you must change the link-layer header
62 * for a "cooked" Linux capture, introduce a new DLT_ type (ask
63 * "tcpdump-workers@lists.tcpdump.org" for one, so that you don't give it
64 * a value that collides with a value already being used), and use the
65 * new header in captures of that type, so that programs that can
66 * handle DLT_LINUX_SLL captures will continue to handle them correctly
67 * without any change, and so that capture files with different headers
68 * can be told apart and programs that read them can dissect the
69 * packets in them.
70 *
71 * This structure, and the #defines below, must be the same in the
72 * libpcap and tcpdump versions of "sll.h".
73 */
74
75/*
76 * A DLT_LINUX_SLL fake link-layer header.
77 */
78#define SLL_HDR_LEN	16		/* total header length */
79#define SLL_ADDRLEN	8		/* length of address field */
80
81struct sll_header {
82	u_int16_t	sll_pkttype;	/* packet type */
83	u_int16_t	sll_hatype;	/* link-layer address type */
84	u_int16_t	sll_halen;	/* link-layer address length */
85	u_int8_t	sll_addr[SLL_ADDRLEN];	/* link-layer address */
86	u_int16_t	sll_protocol;	/* protocol */
87};
88
89/*
90 * The LINUX_SLL_ values for "sll_pkttype"; these correspond to the
91 * PACKET_ values on Linux, but are defined here so that they're
92 * available even on systems other than Linux, and so that they
93 * don't change even if the PACKET_ values change.
94 */
95#define LINUX_SLL_HOST		0
96#define LINUX_SLL_BROADCAST	1
97#define LINUX_SLL_MULTICAST	2
98#define LINUX_SLL_OTHERHOST	3
99#define LINUX_SLL_OUTGOING	4
100
101/*
102 * The LINUX_SLL_ values for "sll_protocol"; these correspond to the
103 * ETH_P_ values on Linux, but are defined here so that they're
104 * available even on systems other than Linux.  We assume, for now,
105 * that the ETH_P_ values won't change in Linux; if they do, then:
106 *
107 *	if we don't translate them in "pcap-linux.c", capture files
108 *	won't necessarily be readable if captured on a system that
109 *	defines ETH_P_ values that don't match these values;
110 *
111 *	if we do translate them in "pcap-linux.c", that makes life
112 *	unpleasant for the BPF code generator, as the values you test
113 *	for in the kernel aren't the values that you test for when
114 *	reading a capture file, so the fixup code run on BPF programs
115 *	handed to the kernel ends up having to do more work.
116 *
117 * Add other values here as necessary, for handling packet types that
118 * might show up on non-Ethernet, non-802.x networks.  (Not all the ones
119 * in the Linux "if_ether.h" will, I suspect, actually show up in
120 * captures.)
121 */
122#define LINUX_SLL_P_802_3	0x0001	/* Novell 802.3 frames without 802.2 LLC header */
123#define LINUX_SLL_P_802_2	0x0004	/* 802.2 frames (not D/I/X Ethernet) */
124