xref: /freebsd/contrib/tcpdump/print-ipcomp.c (revision f4b37ed0f8b307b1f3f0f630ca725d68f1dff30d)
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 #define NETDISSECT_REWORKED
23 #ifdef HAVE_CONFIG_H
24 #include "config.h"
25 #endif
26 
27 #include <tcpdump-stdinc.h>
28 
29 struct ipcomp {
30 	uint8_t comp_nxt;	/* Next Header */
31 	uint8_t comp_flags;	/* Length of data, in 32bit */
32 	uint16_t comp_cpi;	/* Compression parameter index */
33 };
34 
35 #if defined(HAVE_LIBZ) && defined(HAVE_ZLIB_H)
36 #include <zlib.h>
37 #endif
38 
39 #include "interface.h"
40 #include "extract.h"
41 
42 int
43 ipcomp_print(netdissect_options *ndo, register const u_char *bp, int *nhdr _U_)
44 {
45 	register const struct ipcomp *ipcomp;
46 	register const u_char *ep;
47 	uint16_t cpi;
48 #if defined(HAVE_LIBZ) && defined(HAVE_ZLIB_H)
49 	int advance;
50 #endif
51 
52 	ipcomp = (struct ipcomp *)bp;
53 	cpi = EXTRACT_16BITS(&ipcomp->comp_cpi);
54 
55 	/* 'ep' points to the end of available data. */
56 	ep = ndo->ndo_snapend;
57 
58 	if ((u_char *)(ipcomp + 1) >= ep - sizeof(struct ipcomp)) {
59 		ND_PRINT((ndo, "[|IPCOMP]"));
60 		goto fail;
61 	}
62 	ND_PRINT((ndo, "IPComp(cpi=0x%04x)", cpi));
63 
64 #if defined(HAVE_LIBZ) && defined(HAVE_ZLIB_H)
65 	if (1)
66 		goto fail;
67 
68 	/*
69 	 * We may want to decompress the packet here.  Packet buffer
70 	 * management is a headache (if we decompress, packet will become
71 	 * larger).
72 	 */
73 	if (nhdr)
74 		*nhdr = ipcomp->comp_nxt;
75 	advance = sizeof(struct ipcomp);
76 
77 	ND_PRINT((ndo, ": "));
78 	return advance;
79 
80 #endif
81 fail:
82 	return -1;
83 }
84