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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. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *      This product includes software developed by the University of
21  *      California, Berkeley and its contributors.
22  * 4. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  */
38 
39 /*
40  * For captures on Linux cooked sockets, we construct a fake header
41  * that includes:
42  *
43  *	a 2-byte "packet type" which is one of:
44  *
45  *		LINUX_SLL_HOST		packet was sent to us
46  *		LINUX_SLL_BROADCAST	packet was broadcast
47  *		LINUX_SLL_MULTICAST	packet was multicast
48  *		LINUX_SLL_OTHERHOST	packet was sent to somebody else
49  *		LINUX_SLL_OUTGOING	packet was sent *by* us;
50  *
51  *	a 2-byte Ethernet protocol field;
52  *
53  *	a 2-byte link-layer type;
54  *
55  *	a 2-byte link-layer address length;
56  *
57  *	an 8-byte source link-layer address, whose actual length is
58  *	specified by the previous value.
59  *
60  * All fields except for the link-layer address are in network byte order.
61  *
62  * DO NOT change the layout of this structure, or change any of the
63  * LINUX_SLL_ values below.  If you must change the link-layer header
64  * for a "cooked" Linux capture, introduce a new DLT_ type (ask
65  * "tcpdump-workers@lists.tcpdump.org" for one, so that you don't give it
66  * a value that collides with a value already being used), and use the
67  * new header in captures of that type, so that programs that can
68  * handle DLT_LINUX_SLL captures will continue to handle them correctly
69  * without any change, and so that capture files with different headers
70  * can be told apart and programs that read them can dissect the
71  * packets in them.
72  */
73 
74 #ifndef lib_pcap_sll_h
75 #define lib_pcap_sll_h
76 
77 /*
78  * A DLT_LINUX_SLL fake link-layer header.
79  */
80 #define SLL_HDR_LEN	16		/* total header length */
81 #define SLL_ADDRLEN	8		/* length of address field */
82 
83 struct sll_header {
84 	u_int16_t sll_pkttype;		/* packet type */
85 	u_int16_t sll_hatype;		/* link-layer address type */
86 	u_int16_t sll_halen;		/* link-layer address length */
87 	u_int8_t sll_addr[SLL_ADDRLEN];	/* link-layer address */
88 	u_int16_t sll_protocol;		/* protocol */
89 };
90 
91 /*
92  * The LINUX_SLL_ values for "sll_pkttype"; these correspond to the
93  * PACKET_ values on Linux, but are defined here so that they're
94  * available even on systems other than Linux, and so that they
95  * don't change even if the PACKET_ values change.
96  */
97 #define LINUX_SLL_HOST		0
98 #define LINUX_SLL_BROADCAST	1
99 #define LINUX_SLL_MULTICAST	2
100 #define LINUX_SLL_OTHERHOST	3
101 #define LINUX_SLL_OUTGOING	4
102 
103 /*
104  * The LINUX_SLL_ values for "sll_protocol"; these correspond to the
105  * ETH_P_ values on Linux, but are defined here so that they're
106  * available even on systems other than Linux.  We assume, for now,
107  * that the ETH_P_ values won't change in Linux; if they do, then:
108  *
109  *	if we don't translate them in "pcap-linux.c", capture files
110  *	won't necessarily be readable if captured on a system that
111  *	defines ETH_P_ values that don't match these values;
112  *
113  *	if we do translate them in "pcap-linux.c", that makes life
114  *	unpleasant for the BPF code generator, as the values you test
115  *	for in the kernel aren't the values that you test for when
116  *	reading a capture file, so the fixup code run on BPF programs
117  *	handed to the kernel ends up having to do more work.
118  *
119  * Add other values here as necessary, for handling packet types that
120  * might show up on non-Ethernet, non-802.x networks.  (Not all the ones
121  * in the Linux "if_ether.h" will, I suspect, actually show up in
122  * captures.)
123  */
124 #define LINUX_SLL_P_802_3	0x0001	/* Novell 802.3 frames without 802.2 LLC header */
125 #define LINUX_SLL_P_802_2	0x0004	/* 802.2 frames (not D/I/X Ethernet) */
126 #define LINUX_SLL_P_CAN		0x000C	/* CAN frames, with SocketCAN pseudo-headers */
127 #define LINUX_SLL_P_CANFD	0x000D	/* CAN FD frames, with SocketCAN pseudo-headers */
128 
129 #endif
130