sll.h
Author: cmaier@cmassoc.net

    /*-
     * Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
     *	The Regents of the University of California.  All rights reserved.
     *
     * This code is derived from the Stanford/CMU enet packet filter,
     * (net/enet.c) distributed as part of 4.3BSD, and code contributed
     * to Berkeley by Steven McCanne and Van Jacobson both of Lawrence
     * Berkeley Laboratory.
     *
     * 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.
     *
     * @(#) $Header: /tcpdump/master/libpcap/pcap/sll.h,v 1.2.2.1 2008-05-30 01:36:06 guy Exp $ (LBL)
     */

    /*
     * For captures on Linux cooked sockets, we construct a fake header
     * that includes:
     *
     *	a 2-byte "packet type" which is one of:
     *
     *		LINUX_SLL_HOST		packet was sent to us
     *		LINUX_SLL_BROADCAST	packet was broadcast
     *		LINUX_SLL_MULTICAST	packet was multicast
     *		LINUX_SLL_OTHERHOST	packet was sent to somebody else
     *		LINUX_SLL_OUTGOING	packet was sent *by* us;
     *
     *	a 2-byte Ethernet protocol field;
     *
     *	a 2-byte link-layer type;
     *
     *	a 2-byte link-layer address length;
     *
     *	an 8-byte source link-layer address, whose actual length is
     *	specified by the previous value.
     *
     * All fields except for the link-layer address are in network byte order.
     *
     * DO NOT change the layout of this structure, or change any of the
     * LINUX_SLL_ values below.  If you must change the link-layer header
     * for a "cooked" Linux capture, introduce a new DLT_ type (ask
     * "tcpdump-workers@lists.tcpdump.org" for one, so that you don't give it
     * a value that collides with a value already being used), and use the
     * new header in captures of that type, so that programs that can
     * handle DLT_LINUX_SLL captures will continue to handle them correctly
     * without any change, and so that capture files with different headers
     * can be told apart and programs that read them can dissect the
     * packets in them.
     */

    #ifndef lib_pcap_sll_h
    #define lib_pcap_sll_h

    /*
     * A DLT_LINUX_SLL fake link-layer header.
     */
    #define SLL_HDR_LEN	16		/* total header length */
    #define SLL_ADDRLEN	8		/* length of address field */

    struct sll_header {
    	u_int16_t sll_pkttype;		/* packet type */
    	u_int16_t sll_hatype;		/* link-layer address type */
    	u_int16_t sll_halen;		/* link-layer address length */
    	u_int8_t sll_addr[SLL_ADDRLEN];	/* link-layer address */
    	u_int16_t sll_protocol;		/* protocol */
    };

    /*
     * The LINUX_SLL_ values for "sll_pkttype"; these correspond to the
     * PACKET_ values on Linux, but are defined here so that they're
     * available even on systems other than Linux, and so that they
     * don't change even if the PACKET_ values change.
     */
    #define LINUX_SLL_HOST		0
    #define LINUX_SLL_BROADCAST	1
    #define LINUX_SLL_MULTICAST	2
    #define LINUX_SLL_OTHERHOST	3
    #define LINUX_SLL_OUTGOING	4

    /*
     * The LINUX_SLL_ values for "sll_protocol"; these correspond to the
     * ETH_P_ values on Linux, but are defined here so that they're
     * available even on systems other than Linux.  We assume, for now,
     * that the ETH_P_ values won't change in Linux; if they do, then:
     *
     *	if we don't translate them in "pcap-linux.c", capture files
     *	won't necessarily be readable if captured on a system that
     *	defines ETH_P_ values that don't match these values;
     *
     *	if we do translate them in "pcap-linux.c", that makes life
     *	unpleasant for the BPF code generator, as the values you test
     *	for in the kernel aren't the values that you test for when
     *	reading a capture file, so the fixup code run on BPF programs
     *	handed to the kernel ends up having to do more work.
     *
     * Add other values here as necessary, for handling packet types that
     * might show up on non-Ethernet, non-802.x networks.  (Not all the ones
     * in the Linux "if_ether.h" will, I suspect, actually show up in
     * captures.)
     */
    #define LINUX_SLL_P_802_3	0x0001	/* Novell 802.3 frames without 802.2 LLC header */
    #define LINUX_SLL_P_802_2	0x0004	/* 802.2 frames (not D/I/X Ethernet) */

    #endif

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