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
carp_print(netdissect_options * ndo,const u_char * bp,u_int len,u_int ttl)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