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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 <netinet/in.h>
  48
  49 #include "interface.h"
  50 #include "extract.h"
  51 #include "addrtoname.h"
  52
  53 void
  54 carp_print(register const u_char *bp, register u_int len, int ttl)
  55 {
  56         int version, type;
  57         const char *type_s;
  58
  59         TCHECK(bp[0]);
  60         version = (bp[0] & 0xf0) >> 4;
  61         type = bp[0] & 0x0f;
  62         if (type == 1)
  63                 type_s = "advertise";
  64         else
  65                 type_s = "unknown";
  66         printf("CARPv%d-%s %d: ", version, type_s, len);
  67         if (ttl != 255)
  68                 printf("[ttl=%d!] ", ttl);
  69         if (version != 2 || type != 1)
  70                 return;
  71         TCHECK(bp[2]);
  72         TCHECK(bp[5]);
  73         printf("vhid=%d advbase=%d advskew=%d authlen=%d ",
  74             bp[1], bp[5], bp[2], bp[3]);
  75         if (vflag) {
  76                 struct cksum_vec vec[1];
  77                 vec[0].ptr = (const u_int8_t *)bp;
  78                 vec[0].len = len;
  79                 if (TTEST2(bp[0], len) && in_cksum(vec, 1))
  80                         printf(" (bad carp cksum %x!)",
  81                                 EXTRACT_16BITS(&bp[6]));
  82         }
  83         printf("counter=%" PRIu64, EXTRACT_64BITS(&bp[8]));
  84
  85         return;
  86 trunc:
  87         printf("[|carp]");
  88 }