libnet  latest
A Portable Framework for Low-Level Network Packet Construction
sll.h
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  * @(#) $Header: /tcpdump/master/libpcap/pcap/sll.h,v 1.2.2.1 2008-05-30 01:36:06 guy Exp $ (LBL)
39  */
40 
41 /*
42  * For captures on Linux cooked sockets, we construct a fake header
43  * that includes:
44  *
45  * a 2-byte "packet type" which is one of:
46  *
47  * LINUX_SLL_HOST packet was sent to us
48  * LINUX_SLL_BROADCAST packet was broadcast
49  * LINUX_SLL_MULTICAST packet was multicast
50  * LINUX_SLL_OTHERHOST packet was sent to somebody else
51  * LINUX_SLL_OUTGOING packet was sent *by* us;
52  *
53  * a 2-byte Ethernet protocol field;
54  *
55  * a 2-byte link-layer type;
56  *
57  * a 2-byte link-layer address length;
58  *
59  * an 8-byte source link-layer address, whose actual length is
60  * specified by the previous value.
61  *
62  * All fields except for the link-layer address are in network byte order.
63  *
64  * DO NOT change the layout of this structure, or change any of the
65  * LINUX_SLL_ values below. If you must change the link-layer header
66  * for a "cooked" Linux capture, introduce a new DLT_ type (ask
67  * "tcpdump-workers@lists.tcpdump.org" for one, so that you don't give it
68  * a value that collides with a value already being used), and use the
69  * new header in captures of that type, so that programs that can
70  * handle DLT_LINUX_SLL captures will continue to handle them correctly
71  * without any change, and so that capture files with different headers
72  * can be told apart and programs that read them can dissect the
73  * packets in them.
74  */
75 
76 #ifndef lib_pcap_sll_h
77 #define lib_pcap_sll_h
78 
79 /*
80  * A DLT_LINUX_SLL fake link-layer header.
81  */
82 #define SLL_HDR_LEN 16 /* total header length */
83 #define SLL_ADDRLEN 8 /* length of address field */
84 
85 struct sll_header {
86  u_int16_t sll_pkttype; /* packet type */
87  u_int16_t sll_hatype; /* link-layer address type */
88  u_int16_t sll_halen; /* link-layer address length */
89  u_int8_t sll_addr[SLL_ADDRLEN]; /* link-layer address */
90  u_int16_t sll_protocol; /* protocol */
91 };
92 
93 /*
94  * The LINUX_SLL_ values for "sll_pkttype"; these correspond to the
95  * PACKET_ values on Linux, but are defined here so that they're
96  * available even on systems other than Linux, and so that they
97  * don't change even if the PACKET_ values change.
98  */
99 #define LINUX_SLL_HOST 0
100 #define LINUX_SLL_BROADCAST 1
101 #define LINUX_SLL_MULTICAST 2
102 #define LINUX_SLL_OTHERHOST 3
103 #define LINUX_SLL_OUTGOING 4
104 
105 /*
106  * The LINUX_SLL_ values for "sll_protocol"; these correspond to the
107  * ETH_P_ values on Linux, but are defined here so that they're
108  * available even on systems other than Linux. We assume, for now,
109  * that the ETH_P_ values won't change in Linux; if they do, then:
110  *
111  * if we don't translate them in "pcap-linux.c", capture files
112  * won't necessarily be readable if captured on a system that
113  * defines ETH_P_ values that don't match these values;
114  *
115  * if we do translate them in "pcap-linux.c", that makes life
116  * unpleasant for the BPF code generator, as the values you test
117  * for in the kernel aren't the values that you test for when
118  * reading a capture file, so the fixup code run on BPF programs
119  * handed to the kernel ends up having to do more work.
120  *
121  * Add other values here as necessary, for handling packet types that
122  * might show up on non-Ethernet, non-802.x networks. (Not all the ones
123  * in the Linux "if_ether.h" will, I suspect, actually show up in
124  * captures.)
125  */
126 #define LINUX_SLL_P_802_3 0x0001 /* Novell 802.3 frames without 802.2 LLC header */
127 #define LINUX_SLL_P_802_2 0x0004 /* 802.2 frames (not D/I/X Ethernet) */
128 
129 #endif
Definition: sll.h:85