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1 office 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 #define NETDISSECT_REWORKED
38 #ifdef HAVE_CONFIG_H
39 #include "config.h"
40 #endif
41  
42 #include <tcpdump-stdinc.h>
43  
44 #include "interface.h" /* for checksum structure and functions */
45 #include "extract.h"
46  
47 void
48 carp_print(netdissect_options *ndo, register const u_char *bp, register u_int len, int ttl)
49 {
50 int version, type;
51 const char *type_s;
52  
53 ND_TCHECK(bp[0]);
54 version = (bp[0] & 0xf0) >> 4;
55 type = bp[0] & 0x0f;
56 if (type == 1)
57 type_s = "advertise";
58 else
59 type_s = "unknown";
60 ND_PRINT((ndo, "CARPv%d-%s %d: ", version, type_s, len));
61 if (ttl != 255)
62 ND_PRINT((ndo, "[ttl=%d!] ", ttl));
63 if (version != 2 || type != 1)
64 return;
65 ND_TCHECK(bp[2]);
66 ND_TCHECK(bp[5]);
67 ND_PRINT((ndo, "vhid=%d advbase=%d advskew=%d authlen=%d ",
68 bp[1], bp[5], bp[2], 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_TTEST2(bp[0], len) && in_cksum(vec, 1))
74 ND_PRINT((ndo, " (bad carp cksum %x!)",
75 EXTRACT_16BITS(&bp[6])));
76 }
77 ND_PRINT((ndo, "counter=%" PRIu64, EXTRACT_64BITS(&bp[8])));
78  
79 return;
80 trunc:
81 ND_PRINT((ndo, "[|carp]"));
82 }