/*      $OpenBSD: print-carp.c,v 1.6 2009/10/27 23:59:55 deraadt Exp $  */

/*
* Copyright (c) 2000 William C. Fenner.
*                All rights reserved.
*
* Kevin Steves <[email protected]> July 2000
* Modified to:
* - print version, type string and packet length
* - print IP address count if > 1 (-v)
* - verify checksum (-v)
* - print authentication string (-v)
*
* Copyright (c) 2011 Advanced Computing Technologies
* George V. Neille-Neil
*
* Modified to:
* - work correctly with CARP
* - compile into the latest tcpdump
* - print out the counter
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that: (1) source code
* distributions retain the above copyright notice and this paragraph
* in its entirety, and (2) distributions including binary code include
* the above copyright notice and this paragraph in its entirety in
* the documentation or other materials provided with the distribution.
* The name of William C. Fenner may not be used to endorse or
* promote products derived from this software without specific prior
* written permission.  THIS SOFTWARE IS PROVIDED ``AS IS'' AND
* WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
* LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE.
*
*/

#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: print-carp.c,v 1.5 2024/09/02 16:15:30 christos Exp $");
#endif

/* \summary: Common Address Redundancy Protocol (CARP) printer */

#include <config.h>

#include "netdissect-stdinc.h"

#include "netdissect.h" /* for checksum structure and functions */
#include "extract.h"

void
carp_print(netdissect_options *ndo, const u_char *bp, u_int len, u_int ttl)
{
       u_int version, type;
       const char *type_s;

       ndo->ndo_protocol = "carp";
       nd_print_protocol_caps(ndo);
       version = (GET_U_1(bp) & 0xf0) >> 4;
       type = GET_U_1(bp) & 0x0f;
       if (type == 1)
               type_s = "advertise";
       else
               type_s = "unknown";
       ND_PRINT("v%u-%s %u: ", version, type_s, len);
       if (ttl != 255)
               ND_PRINT("[ttl=%u!] ", ttl);
       if (version != 2 || type != 1)
               return;
       ND_PRINT("vhid=%u advbase=%u advskew=%u authlen=%u ",
           GET_U_1(bp + 1), GET_U_1(bp + 5), GET_U_1(bp + 2),
           GET_U_1(bp + 3));
       if (ndo->ndo_vflag) {
               struct cksum_vec vec[1];
               vec[0].ptr = (const uint8_t *)bp;
               vec[0].len = len;
               if (ND_TTEST_LEN(bp, len) && in_cksum(vec, 1))
                       ND_PRINT(" (bad carp cksum %x!)",
                               GET_BE_U_2(bp + 6));
       }
       ND_PRINT("counter=%" PRIu64, GET_BE_U_8(bp + 8));
}