xref: /openbsd-src/usr.sbin/tcpdump/print-carp.c (revision a28daedfc357b214be5c701aa8ba8adb29a7f1c2)
1 /*	$OpenBSD: print-carp.c,v 1.5 2007/10/07 16:41:05 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  * Redistribution and use in source and binary forms, with or without
15  * modification, are permitted provided that: (1) source code
16  * distributions retain the above copyright notice and this paragraph
17  * in its entirety, and (2) distributions including binary code include
18  * the above copyright notice and this paragraph in its entirety in
19  * the documentation or other materials provided with the distribution.
20  * The name of William C. Fenner may not be used to endorse or
21  * promote products derived from this software without specific prior
22  * written permission.  THIS SOFTWARE IS PROVIDED ``AS IS'' AND
23  * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
24  * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
25  * FOR A PARTICULAR PURPOSE.
26  *
27  * from tcpdump.org:
28  * Header: /tcpdump/master/tcpdump/print-vrrp.c,v 1.3 2000/10/10 05:05:08 guy Exp
29  */
30 
31 #ifndef lint
32 static const char rcsid[] =
33     "@(#) $Id: print-carp.c,v 1.5 2007/10/07 16:41:05 deraadt Exp $";
34 #endif
35 
36 #ifdef HAVE_CONFIG_H
37 #include "config.h"
38 #endif
39 
40 #include <stdio.h>
41 #include <stdlib.h>
42 #include <unistd.h>
43 
44 #include <netinet/in.h>
45 
46 #include "interface.h"
47 #include "extract.h"
48 #include "addrtoname.h"
49 
50 void
51 carp_print(register const u_char *bp, register u_int len, int ttl)
52 {
53 	int version, type;
54 	char *type_s;
55 
56 	TCHECK(bp[0]);
57 	version = (bp[0] & 0xf0) >> 4;
58 	type = bp[0] & 0x0f;
59 	if (type == 1)
60 		type_s = "advertise";
61 	else
62 		type_s = "unknown";
63 	printf("CARPv%d-%s %d: ", version, type_s, len);
64 	if (ttl != 255)
65 		printf("[ttl=%d!] ", ttl);
66 	if (version != 2 || type != 1)
67 		return;
68 	TCHECK(bp[2]);
69 	TCHECK(bp[5]);
70 	printf("vhid=%d advbase=%d advskew=%d demote=%d",
71 	    bp[1], bp[5], bp[2], bp[4]);
72 	if (vflag) {
73 		if (TTEST2(bp[0], len) && in_cksum((const u_short*)bp, len, 0))
74 			printf(" (bad carp cksum %x!)",
75 				EXTRACT_16BITS(&bp[6]));
76 	}
77 	return;
78 trunc:
79 	printf("[|carp]");
80 }
81