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 /* \summary: Common Address Redundancy Protocol (CARP) printer */
  38
  39 #include <config.h>
  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, const u_char *bp, u_int len, u_int ttl)
  48 {
  49         u_int version, type;
  50         const char *type_s;
  51
  52         ndo->ndo_protocol = "carp";
  53         nd_print_protocol_caps(ndo);
  54         version = (GET_U_1(bp) & 0xf0) >> 4;
  55         type = GET_U_1(bp) & 0x0f;
  56         if (type == 1)
  57                 type_s = "advertise";
  58         else
  59                 type_s = "unknown";
  60         ND_PRINT("v%u-%s %u: ", version, type_s, len);
  61         if (ttl != 255)
  62                 ND_PRINT("[ttl=%u!] ", ttl);
  63         if (version != 2 || type != 1)
  64                 return;
  65         ND_PRINT("vhid=%u advbase=%u advskew=%u authlen=%u ",
  66             GET_U_1(bp + 1), GET_U_1(bp + 5), GET_U_1(bp + 2),
  67             GET_U_1(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_TTEST_LEN(bp, len) && in_cksum(vec, 1))
  73                         ND_PRINT(" (bad carp cksum %x!)",
  74                                 GET_BE_U_2(bp + 6));
  75         }
  76         ND_PRINT("counter=%" PRIu64, GET_BE_U_8(bp + 8));
  77 }