xref: /freebsd/contrib/tcpdump/print-ipcomp.c (revision 82431678fce5c893ef9c7418ad6d998ad4187de6)
1 /*
2  * Copyright (c) 1988, 1989, 1990, 1991, 1993, 1994
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that: (1) source code distributions
7  * retain the above copyright notice and this paragraph in its entirety, (2)
8  * distributions including binary code include the above copyright notice and
9  * this paragraph in its entirety in the documentation or other materials
10  * provided with the distribution, and (3) all advertising materials mentioning
11  * features or use of this software display the following acknowledgement:
12  * ``This product includes software developed by the University of California,
13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
14  * the University nor the names of its contributors may be used to endorse
15  * or promote products derived from this software without specific prior
16  * written permission.
17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
20  */
21 
22 #ifndef lint
23 static const char rcsid[] _U_ =
24     "@(#) $Header: /tcpdump/master/tcpdump/print-ipcomp.c,v 1.20 2003-11-19 00:36:08 guy Exp $";
25 #endif
26 
27 #ifdef HAVE_CONFIG_H
28 #include "config.h"
29 #endif
30 
31 #include <string.h>
32 #include <tcpdump-stdinc.h>
33 
34 #include <stdio.h>
35 
36 struct ipcomp {
37 	u_int8_t comp_nxt;	/* Next Header */
38 	u_int8_t comp_flags;	/* Length of data, in 32bit */
39 	u_int16_t comp_cpi;	/* Compression parameter index */
40 };
41 
42 #if defined(HAVE_LIBZ) && defined(HAVE_ZLIB_H)
43 #include <zlib.h>
44 #endif
45 
46 #include "interface.h"
47 #include "addrtoname.h"
48 #include "extract.h"
49 
50 int
51 ipcomp_print(register const u_char *bp, int *nhdr _U_)
52 {
53 	register const struct ipcomp *ipcomp;
54 	register const u_char *ep;
55 	u_int16_t cpi;
56 #if defined(HAVE_LIBZ) && defined(HAVE_ZLIB_H)
57 	int advance;
58 #endif
59 
60 	ipcomp = (struct ipcomp *)bp;
61 	cpi = EXTRACT_16BITS(&ipcomp->comp_cpi);
62 
63 	/* 'ep' points to the end of available data. */
64 	ep = snapend;
65 
66 	if ((u_char *)(ipcomp + 1) >= ep - sizeof(struct ipcomp)) {
67 		fputs("[|IPCOMP]", stdout);
68 		goto fail;
69 	}
70 	printf("IPComp(cpi=0x%04x)", cpi);
71 
72 #if defined(HAVE_LIBZ) && defined(HAVE_ZLIB_H)
73 	if (1)
74 		goto fail;
75 
76 	/*
77 	 * We may want to decompress the packet here.  Packet buffer
78 	 * management is a headache (if we decompress, packet will become
79 	 * larger).
80 	 */
81 	if (nhdr)
82 		*nhdr = ipcomp->comp_nxt;
83 	advance = sizeof(struct ipcomp);
84 
85 	printf(": ");
86 	return advance;
87 
88 #endif
89 fail:
90 	return -1;
91 }
92