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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 #include <unistd.h>
  46
  47 #include "interface.h"
  48 #include "extract.h"
  49 #include "addrtoname.h"
  50
  51 void
  52 carp_print(register const u_char *bp, register u_int len, int ttl)
  53 {
  54         int version, type;
  55         const char *type_s;
  56
  57         TCHECK(bp[0]);
  58         version = (bp[0] & 0xf0) >> 4;
  59         type = bp[0] & 0x0f;
  60         if (type == 1)
  61                 type_s = "advertise";
  62         else
  63                 type_s = "unknown";
  64         printf("CARPv%d-%s %d: ", version, type_s, len);
  65         if (ttl != 255)
  66                 printf("[ttl=%d!] ", ttl);
  67         if (version != 2 || type != 1)
  68                 return;
  69         TCHECK(bp[2]);
  70         TCHECK(bp[5]);
  71         printf("vhid=%d advbase=%d advskew=%d authlen=%d ",
  72             bp[1], bp[5], bp[2], bp[3]);
  73         if (vflag) {
  74                 struct cksum_vec vec[1];
  75                 vec[0].ptr = (const u_int8_t *)bp;
  76                 vec[0].len = len;
  77                 if (TTEST2(bp[0], len) && in_cksum(vec, 1))
  78                         printf(" (bad carp cksum %x!)",
  79                                 EXTRACT_16BITS(&bp[6]));
  80         }
  81         printf("counter=%" PRIu64, EXTRACT_64BITS(&bp[8]));
  82
  83         return;
  84 trunc:
  85         printf("[|carp]");
  86 }