xref: /aosp_15_r20/external/tcpdump/print-ipcomp.c (revision 05b00f6010a2396e3db2409989fc67270046269f)
1*05b00f60SXin Li /*
2*05b00f60SXin Li  * Copyright (c) 1988, 1989, 1990, 1991, 1993, 1994
3*05b00f60SXin Li  *	The Regents of the University of California.  All rights reserved.
4*05b00f60SXin Li  *
5*05b00f60SXin Li  * Redistribution and use in source and binary forms, with or without
6*05b00f60SXin Li  * modification, are permitted provided that: (1) source code distributions
7*05b00f60SXin Li  * retain the above copyright notice and this paragraph in its entirety, (2)
8*05b00f60SXin Li  * distributions including binary code include the above copyright notice and
9*05b00f60SXin Li  * this paragraph in its entirety in the documentation or other materials
10*05b00f60SXin Li  * provided with the distribution, and (3) all advertising materials mentioning
11*05b00f60SXin Li  * features or use of this software display the following acknowledgement:
12*05b00f60SXin Li  * ``This product includes software developed by the University of California,
13*05b00f60SXin Li  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
14*05b00f60SXin Li  * the University nor the names of its contributors may be used to endorse
15*05b00f60SXin Li  * or promote products derived from this software without specific prior
16*05b00f60SXin Li  * written permission.
17*05b00f60SXin Li  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
18*05b00f60SXin Li  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
19*05b00f60SXin Li  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
20*05b00f60SXin Li  */
21*05b00f60SXin Li 
22*05b00f60SXin Li /* \summary: IP Payload Compression Protocol (IPComp) printer */
23*05b00f60SXin Li 
24*05b00f60SXin Li #ifdef HAVE_CONFIG_H
25*05b00f60SXin Li #include <config.h>
26*05b00f60SXin Li #endif
27*05b00f60SXin Li 
28*05b00f60SXin Li #include "netdissect-stdinc.h"
29*05b00f60SXin Li 
30*05b00f60SXin Li #include "netdissect.h"
31*05b00f60SXin Li #include "extract.h"
32*05b00f60SXin Li 
33*05b00f60SXin Li struct ipcomp {
34*05b00f60SXin Li 	nd_uint8_t  comp_nxt;	/* Next Header */
35*05b00f60SXin Li 	nd_uint8_t  comp_flags;	/* Length of data, in 32bit */
36*05b00f60SXin Li 	nd_uint16_t comp_cpi;	/* Compression parameter index */
37*05b00f60SXin Li };
38*05b00f60SXin Li 
39*05b00f60SXin Li void
ipcomp_print(netdissect_options * ndo,const u_char * bp)40*05b00f60SXin Li ipcomp_print(netdissect_options *ndo, const u_char *bp)
41*05b00f60SXin Li {
42*05b00f60SXin Li 	const struct ipcomp *ipcomp;
43*05b00f60SXin Li 	uint16_t cpi;
44*05b00f60SXin Li 
45*05b00f60SXin Li 	ndo->ndo_protocol = "ipcomp";
46*05b00f60SXin Li 	ipcomp = (const struct ipcomp *)bp;
47*05b00f60SXin Li 	cpi = GET_BE_U_2(ipcomp->comp_cpi);
48*05b00f60SXin Li 
49*05b00f60SXin Li 	ND_PRINT("IPComp(cpi=0x%04x)", cpi);
50*05b00f60SXin Li 
51*05b00f60SXin Li 	/*
52*05b00f60SXin Li 	 * XXX - based on the CPI, we could decompress the packet here.
53*05b00f60SXin Li 	 * Packet buffer management is a headache (if we decompress,
54*05b00f60SXin Li 	 * packet will become larger).
55*05b00f60SXin Li 	 *
56*05b00f60SXin Li 	 * We would decompress the packet and then call a routine that,
57*05b00f60SXin Li 	 * based on ipcomp->comp_nxt, dissects the decompressed data.
58*05b00f60SXin Li 	 *
59*05b00f60SXin Li 	 * Until we do that, however, we just return -1, so that
60*05b00f60SXin Li 	 * the loop that processes "protocol"/"next header" types
61*05b00f60SXin Li 	 * stops - there's nothing more it can do with a compressed
62*05b00f60SXin Li 	 * payload.
63*05b00f60SXin Li 	 */
64*05b00f60SXin Li }
65