xref: /freebsd/contrib/tcpdump/print-carp.c (revision a03411e84728e9b267056fd31c7d1d9d1dc1b01e)
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 #ifdef HAVE_CONFIG_H
40 #include <config.h>
41 #endif
42 
43 #include "netdissect-stdinc.h"
44 
45 #include "netdissect.h" /* for checksum structure and functions */
46 #include "extract.h"
47 
48 void
49 carp_print(netdissect_options *ndo, const u_char *bp, u_int len, u_int ttl)
50 {
51 	u_int version, type;
52 	const char *type_s;
53 
54 	ndo->ndo_protocol = "carp";
55 	version = (GET_U_1(bp) & 0xf0) >> 4;
56 	type = GET_U_1(bp) & 0x0f;
57 	if (type == 1)
58 		type_s = "advertise";
59 	else
60 		type_s = "unknown";
61 	ND_PRINT("CARPv%u-%s %u: ", version, type_s, len);
62 	if (ttl != 255)
63 		ND_PRINT("[ttl=%u!] ", ttl);
64 	if (version != 2 || type != 1)
65 		return;
66 	ND_PRINT("vhid=%u advbase=%u advskew=%u authlen=%u ",
67 	    GET_U_1(bp + 1), GET_U_1(bp + 5), GET_U_1(bp + 2),
68 	    GET_U_1(bp + 3));
69 	if (ndo->ndo_vflag) {
70 		struct cksum_vec vec[1];
71 		vec[0].ptr = (const uint8_t *)bp;
72 		vec[0].len = len;
73 		if (ND_TTEST_LEN(bp, len) && in_cksum(vec, 1))
74 			ND_PRINT(" (bad carp cksum %x!)",
75 				GET_BE_U_2(bp + 6));
76 	}
77 	ND_PRINT("counter=%" PRIu64, GET_BE_U_8(bp + 8));
78 }
79