xref: /netbsd-src/external/bsd/tcpdump/dist/print-ipcomp.c (revision cc576e1d8e4f4078fd4e81238abca9fca216f6ec)
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 #include <sys/cdefs.h>
23 #ifndef lint
24 __RCSID("$NetBSD: print-ipcomp.c,v 1.5 2017/01/24 23:29:14 christos Exp $");
25 #endif
26 
27 #ifdef HAVE_CONFIG_H
28 #include "config.h"
29 #endif
30 
31 #include <netdissect-stdinc.h>
32 
33 struct ipcomp {
34 	uint8_t comp_nxt;	/* Next Header */
35 	uint8_t comp_flags;	/* Length of data, in 32bit */
36 	uint16_t comp_cpi;	/* Compression parameter index */
37 };
38 
39 #if defined(HAVE_LIBZ) && defined(HAVE_ZLIB_H)
40 #include <zlib.h>
41 #endif
42 
43 #include "netdissect.h"
44 #include "extract.h"
45 
46 int
47 ipcomp_print(netdissect_options *ndo, register const u_char *bp, int *nhdr _U_)
48 {
49 	register const struct ipcomp *ipcomp;
50 	register const u_char *ep;
51 	uint16_t cpi;
52 #if defined(HAVE_LIBZ) && defined(HAVE_ZLIB_H)
53 	int advance;
54 #endif
55 
56 	ipcomp = (const struct ipcomp *)bp;
57 	cpi = EXTRACT_16BITS(&ipcomp->comp_cpi);
58 
59 	/* 'ep' points to the end of available data. */
60 	ep = ndo->ndo_snapend;
61 
62 	if ((const u_char *)(ipcomp + 1) >= ep - sizeof(struct ipcomp)) {
63 		ND_PRINT((ndo, "[|IPCOMP]"));
64 		goto fail;
65 	}
66 	ND_PRINT((ndo, "IPComp(cpi=0x%04x)", cpi));
67 
68 #if defined(HAVE_LIBZ) && defined(HAVE_ZLIB_H)
69 	if (1)
70 		goto fail;
71 
72 	/*
73 	 * We may want to decompress the packet here.  Packet buffer
74 	 * management is a headache (if we decompress, packet will become
75 	 * larger).
76 	 */
77 	if (nhdr)
78 		*nhdr = ipcomp->comp_nxt;
79 	advance = sizeof(struct ipcomp);
80 
81 	ND_PRINT((ndo, ": "));
82 	return advance;
83 
84 #endif
85 fail:
86 	return -1;
87 }
88