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 1.7 2023/08/17 20:19:40 christos Exp $");
25#endif
26
27/* \summary: IP Payload Compression Protocol (IPComp) printer */
28
29#ifdef HAVE_CONFIG_H
30#include <config.h>
31#endif
32
33#include "netdissect-stdinc.h"
34
35#include "netdissect.h"
36#include "extract.h"
37
38struct ipcomp {
39	nd_uint8_t  comp_nxt;	/* Next Header */
40	nd_uint8_t  comp_flags;	/* Length of data, in 32bit */
41	nd_uint16_t comp_cpi;	/* Compression parameter index */
42};
43
44void
45ipcomp_print(netdissect_options *ndo, const u_char *bp)
46{
47	const struct ipcomp *ipcomp;
48	uint16_t cpi;
49
50	ndo->ndo_protocol = "ipcomp";
51	ipcomp = (const struct ipcomp *)bp;
52	cpi = GET_BE_U_2(ipcomp->comp_cpi);
53
54	ND_PRINT("IPComp(cpi=0x%04x)", cpi);
55
56	/*
57	 * XXX - based on the CPI, we could decompress the packet here.
58	 * Packet buffer management is a headache (if we decompress,
59	 * packet will become larger).
60	 *
61	 * We would decompress the packet and then call a routine that,
62	 * based on ipcomp->comp_nxt, dissects the decompressed data.
63	 *
64	 * Until we do that, however, we just return -1, so that
65	 * the loop that processes "protocol"/"next header" types
66	 * stops - there's nothing more it can do with a compressed
67	 * payload.
68	 */
69}
70