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      1 /*	$NetBSD: sll.h,v 1.6 2024/09/02 15:33:39 christos Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * This code is derived from the Stanford/CMU enet packet filter,
      8  * (net/enet.c) distributed as part of 4.3BSD, and code contributed
      9  * to Berkeley by Steven McCanne and Van Jacobson both of Lawrence
     10  * Berkeley Laboratory.
     11  *
     12  * Redistribution and use in source and binary forms, with or without
     13  * modification, are permitted provided that the following conditions
     14  * are met:
     15  * 1. Redistributions of source code must retain the above copyright
     16  *    notice, this list of conditions and the following disclaimer.
     17  * 2. Redistributions in binary form must reproduce the above copyright
     18  *    notice, this list of conditions and the following disclaimer in the
     19  *    documentation and/or other materials provided with the distribution.
     20  * 3. All advertising materials mentioning features or use of this software
     21  *    must display the following acknowledgement:
     22  *      This product includes software developed by the University of
     23  *      California, Berkeley and its contributors.
     24  * 4. Neither the name of the University nor the names of its contributors
     25  *    may be used to endorse or promote products derived from this software
     26  *    without specific prior written permission.
     27  *
     28  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     38  * SUCH DAMAGE.
     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 (at) 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 #include <pcap/pcap-inttypes.h>
     80 
     81 /*
     82  * A DLT_LINUX_SLL fake link-layer header.
     83  */
     84 #define SLL_HDR_LEN	16		/* total header length */
     85 #define SLL_ADDRLEN	8		/* length of address field */
     86 
     87 struct sll_header {
     88 	uint16_t sll_pkttype;		/* packet type */
     89 	uint16_t sll_hatype;		/* link-layer address type */
     90 	uint16_t sll_halen;		/* link-layer address length */
     91 	uint8_t  sll_addr[SLL_ADDRLEN];	/* link-layer address */
     92 	uint16_t sll_protocol;		/* protocol */
     93 };
     94 
     95 /*
     96  * A DLT_LINUX_SLL2 fake link-layer header.
     97  */
     98 #define SLL2_HDR_LEN	20		/* total header length */
     99 
    100 struct sll2_header {
    101 	uint16_t sll2_protocol;			/* protocol */
    102 	uint16_t sll2_reserved_mbz;		/* reserved - must be zero */
    103 	uint32_t sll2_if_index;			/* 1-based interface index */
    104 	uint16_t sll2_hatype;			/* link-layer address type */
    105 	uint8_t  sll2_pkttype;			/* packet type */
    106 	uint8_t  sll2_halen;			/* link-layer address length */
    107 	uint8_t  sll2_addr[SLL_ADDRLEN];	/* link-layer address */
    108 };
    109 
    110 /*
    111  * The LINUX_SLL_ values for "sll_pkttype" and LINUX_SLL2_ values for
    112  * "sll2_pkttype"; these correspond to the PACKET_ values on Linux,
    113  * which are defined by a header under include/uapi in the current
    114  * kernel source, and are thus not going to change on Linux.  We
    115  * define them here so that they're available even on systems other
    116  * than Linux.
    117  */
    118 #define LINUX_SLL_HOST		0
    119 #define LINUX_SLL_BROADCAST	1
    120 #define LINUX_SLL_MULTICAST	2
    121 #define LINUX_SLL_OTHERHOST	3
    122 #define LINUX_SLL_OUTGOING	4
    123 
    124 /*
    125  * The LINUX_SLL_ values for "sll_protocol" and LINUX_SLL2_ values for
    126  * "sll2_protocol"; these correspond to the ETH_P_ values on Linux, but
    127  * are defined here so that they're available even on systems other than
    128  * Linux.  We assume, for now, that the ETH_P_ values won't change in
    129  * Linux; if they do, then:
    130  *
    131  *	if we don't translate them in "pcap-linux.c", capture files
    132  *	won't necessarily be readable if captured on a system that
    133  *	defines ETH_P_ values that don't match these values;
    134  *
    135  *	if we do translate them in "pcap-linux.c", that makes life
    136  *	unpleasant for the BPF code generator, as the values you test
    137  *	for in the kernel aren't the values that you test for when
    138  *	reading a capture file, so the fixup code run on BPF programs
    139  *	handed to the kernel ends up having to do more work.
    140  *
    141  * Add other values here as necessary, for handling packet types that
    142  * might show up on non-Ethernet, non-802.x networks.  (Not all the ones
    143  * in the Linux "if_ether.h" will, I suspect, actually show up in
    144  * captures.)
    145  */
    146 #define LINUX_SLL_P_802_3	0x0001	/* Novell 802.3 frames without 802.2 LLC header */
    147 #define LINUX_SLL_P_802_2	0x0004	/* 802.2 frames (not D/I/X Ethernet) */
    148 #define LINUX_SLL_P_CAN		0x000C	/* CAN frames, with SocketCAN pseudo-headers */
    149 #define LINUX_SLL_P_CANFD	0x000D	/* CAN FD frames, with SocketCAN pseudo-headers */
    150 #define LINUX_SLL_P_CANXL	0x000E	/* CAN XL frames, with SocketCAN pseudo-headers */
    151 
    152 #endif
    153