The Tcpdump Group git mirrors - libpcap/blob - pcap/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. 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
  35 /*
  36  * For captures on Linux cooked sockets, we construct a fake header
  37  * that includes:
  38  *
  39  *      a 2-byte "packet type" which is one of:
  40  *
  41  *              LINUX_SLL_HOST          packet was sent to us
  42  *              LINUX_SLL_BROADCAST     packet was broadcast
  43  *              LINUX_SLL_MULTICAST     packet was multicast
  44  *              LINUX_SLL_OTHERHOST     packet was sent to somebody else
  45  *              LINUX_SLL_OUTGOING      packet was sent *by* us;
  46  *
  47  *      a 2-byte Ethernet protocol field;
  48  *
  49  *      a 2-byte link-layer type;
  50  *
  51  *      a 2-byte link-layer address length;
  52  *
  53  *      an 8-byte source link-layer address, whose actual length is
  54  *      specified by the previous value.
  55  *
  56  * All fields except for the link-layer address are in network byte order.
  57  *
  58  * DO NOT change the layout of this structure, or change any of the
  59  * LINUX_SLL_ values below.  If you must change the link-layer header
  60  * for a "cooked" Linux capture, introduce a new DLT_ type (ask
  61  * "tcpdump-workers@lists.tcpdump.org" for one, so that you don't give it
  62  * a value that collides with a value already being used), and use the
  63  * new header in captures of that type, so that programs that can
  64  * handle DLT_LINUX_SLL captures will continue to handle them correctly
  65  * without any change, and so that capture files with different headers
  66  * can be told apart and programs that read them can dissect the
  67  * packets in them.
  68  */
  69
  70 #ifndef lib_pcap_sll_h
  71 #define lib_pcap_sll_h
  72
  73 #include <pcap/pcap-inttypes.h>
  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
  81 struct sll_header {
  82         uint16_t sll_pkttype;           /* packet type */
  83         uint16_t sll_hatype;            /* link-layer address type */
  84         uint16_t sll_halen;             /* link-layer address length */
  85         uint8_t  sll_addr[SLL_ADDRLEN]; /* link-layer address */
  86         uint16_t sll_protocol;          /* protocol */
  87 };
  88
  89 /*
  90  * A DLT_LINUX_SLL2 fake link-layer header.
  91  */
  92 #define SLL2_HDR_LEN    20              /* total header length */
  93
  94 struct sll2_header {
  95         uint16_t sll2_protocol;                 /* protocol */
  96         uint16_t sll2_reserved_mbz;             /* reserved - must be zero */
  97         uint32_t sll2_if_index;                 /* 1-based interface index */
  98         uint16_t sll2_hatype;                   /* link-layer address type */
  99         uint8_t  sll2_pkttype;                  /* packet type */
 100         uint8_t  sll2_halen;                    /* link-layer address length */
 101         uint8_t  sll2_addr[SLL_ADDRLEN];        /* link-layer address */
 102 };
 103
 104 /*
 105  * The LINUX_SLL_ values for "sll_pkttype" and LINUX_SLL2_ values for
 106  * "sll2_pkttype"; these correspond to the PACKET_ values on Linux,
 107  * which are defined by a header under include/uapi in the current
 108  * kernel source, and are thus not going to change on Linux.  We
 109  * define them here so that they're available even on systems other
 110  * than Linux.
 111  */
 112 #define LINUX_SLL_HOST          0
 113 #define LINUX_SLL_BROADCAST     1
 114 #define LINUX_SLL_MULTICAST     2
 115 #define LINUX_SLL_OTHERHOST     3
 116 #define LINUX_SLL_OUTGOING      4
 117
 118 /*
 119  * The LINUX_SLL_ values for "sll_protocol" and LINUX_SLL2_ values for
 120  * "sll2_protocol"; these correspond to the ETH_P_ values on Linux, but
 121  * are defined here so that they're available even on systems other than
 122  * Linux.  We assume, for now, that the ETH_P_ values won't change in
 123  * Linux; if they do, then:
 124  *
 125  *      if we don't translate them in "pcap-linux.c", capture files
 126  *      won't necessarily be readable if captured on a system that
 127  *      defines ETH_P_ values that don't match these values;
 128  *
 129  *      if we do translate them in "pcap-linux.c", that makes life
 130  *      unpleasant for the BPF code generator, as the values you test
 131  *      for in the kernel aren't the values that you test for when
 132  *      reading a capture file, so the fixup code run on BPF programs
 133  *      handed to the kernel ends up having to do more work.
 134  *
 135  * Add other values here as necessary, for handling packet types that
 136  * might show up on non-Ethernet, non-802.x networks.  (Not all the ones
 137  * in the Linux "if_ether.h" will, I suspect, actually show up in
 138  * captures.)
 139  */
 140 #define LINUX_SLL_P_802_3       0x0001  /* Novell 802.3 frames without 802.2 LLC header */
 141 #define LINUX_SLL_P_802_2       0x0004  /* 802.2 frames (not D/I/X Ethernet) */
 142 #define LINUX_SLL_P_CAN         0x000C  /* CAN frames, with SocketCAN pseudo-headers */
 143 #define LINUX_SLL_P_CANFD       0x000D  /* CAN FD frames, with SocketCAN pseudo-headers */
 144 #define LINUX_SLL_P_CANXL       0x000E  /* CAN XL frames, with SocketCAN pseudo-headers */
 145
 146 #endif