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   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 <tcpdump-stdinc.h>
  42
  43 #include <stdio.h>
  44 #include <stdlib.h>
  45
  46 #include "interface.h"
  47 #include "extract.h"
  48
  49 void
  50 carp_print(register const u_char *bp, register u_int len, int ttl)
  51 {
  52         int version, type;
  53         const char *type_s;
  54
  55         TCHECK(bp[0]);
  56         version = (bp[0] & 0xf0) >> 4;
  57         type = bp[0] & 0x0f;
  58         if (type == 1)
  59                 type_s = "advertise";
  60         else
  61                 type_s = "unknown";
  62         printf("CARPv%d-%s %d: ", version, type_s, len);
  63         if (ttl != 255)
  64                 printf("[ttl=%d!] ", ttl);
  65         if (version != 2 || type != 1)
  66                 return;
  67         TCHECK(bp[2]);
  68         TCHECK(bp[5]);
  69         printf("vhid=%d advbase=%d advskew=%d authlen=%d ",
  70             bp[1], bp[5], bp[2], bp[3]);
  71         if (vflag) {
  72                 struct cksum_vec vec[1];
  73                 vec[0].ptr = (const u_int8_t *)bp;
  74                 vec[0].len = len;
  75                 if (TTEST2(bp[0], len) && in_cksum(vec, 1))
  76                         printf(" (bad carp cksum %x!)",
  77                                 EXTRACT_16BITS(&bp[6]));
  78         }
  79         printf("counter=%" PRIu64, EXTRACT_64BITS(&bp[8]));
  80
  81         return;
  82 trunc:
  83         printf("[|carp]");
  84 }