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
53void
54carp_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;
86trunc:
87	printf("[|carp]");
88}
89