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
carp_print(netdissect_options * ndo,const u_char * bp,u_int len,u_int ttl)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 }
78