The Tcpdump Group git mirrors - tcpdump/blob - print-carp.c

   1 /*      $OpenBSD: print-carp.c,v 1.6 2009/10/27 23:59:55 deraadt Exp $  */
   2
   3 /*
   4  * Copyright (c) 2000 William C. Fenner.
   5  *                All rights reserved.
   6  *
   7  * Kevin Steves <ks@hp.se> July 2000
   8  * Modified to:
   9  * - print version, type string and packet length
  10  * - print IP address count if > 1 (-v)
  11  * - verify checksum (-v)
  12  * - print authentication string (-v)
  13  *
  14  * Copyright (c) 2011 Advanced Computing Technologies
  15  * George V. Neille-Neil
  16  *
  17  * Modified to:
  18  * - work correctly with CARP
  19  * - compile into the latest tcpdump
  20  * - print out the counter
  21  *
  22  * Redistribution and use in source and binary forms, with or without
  23  * modification, are permitted provided that: (1) source code
  24  * distributions retain the above copyright notice and this paragraph
  25  * in its entirety, and (2) distributions including binary code include
  26  * the above copyright notice and this paragraph in its entirety in
  27  * the documentation or other materials provided with the distribution.
  28  * The name of William C. Fenner may not be used to endorse or
  29  * promote products derived from this software without specific prior
  30  * written permission.  THIS SOFTWARE IS PROVIDED ``AS IS'' AND
  31  * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
  32  * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  33  * FOR A PARTICULAR PURPOSE.
  34  *
  35  */
  36
  37 #ifdef HAVE_CONFIG_H
  38 #include "config.h"
  39 #endif
  40
  41 #include <netdissect-stdinc.h>
  42
  43 #include "netdissect.h" /* for checksum structure and functions */
  44 #include "extract.h"
  45
  46 void
  47 carp_print(netdissect_options *ndo, register const u_char *bp, register u_int len, int ttl)
  48 {
  49         int version, type;
  50         const char *type_s;
  51
  52         ND_TCHECK(bp[0]);
  53         version = (bp[0] & 0xf0) >> 4;
  54         type = bp[0] & 0x0f;
  55         if (type == 1)
  56                 type_s = "advertise";
  57         else
  58                 type_s = "unknown";
  59         ND_PRINT((ndo, "CARPv%d-%s %d: ", version, type_s, len));
  60         if (ttl != 255)
  61                 ND_PRINT((ndo, "[ttl=%d!] ", ttl));
  62         if (version != 2 || type != 1)
  63                 return;
  64         ND_TCHECK(bp[2]);
  65         ND_TCHECK(bp[5]);
  66         ND_PRINT((ndo, "vhid=%d advbase=%d advskew=%d authlen=%d ",
  67             bp[1], bp[5], bp[2], bp[3]));
  68         if (ndo->ndo_vflag) {
  69                 struct cksum_vec vec[1];
  70                 vec[0].ptr = (const uint8_t *)bp;
  71                 vec[0].len = len;
  72                 if (ND_TTEST2(bp[0], len) && in_cksum(vec, 1))
  73                         ND_PRINT((ndo, " (bad carp cksum %x!)",
  74                                 EXTRACT_16BITS(&bp[6])));
  75         }
  76         ND_PRINT((ndo, "counter=%" PRIu64, EXTRACT_64BITS(&bp[8])));
  77
  78         return;
  79 trunc:
  80         ND_PRINT((ndo, "[|carp]"));
  81 }