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 /* \summary: IP Payload Compression Protocol (IPComp) printer */
23
24 #ifdef HAVE_CONFIG_H
25 #include "config.h"
26 #endif
27
28 #include <netdissect-stdinc.h>
29
30 struct ipcomp {
31 uint8_t comp_nxt; /* Next Header */
32 uint8_t comp_flags; /* Length of data, in 32bit */
33 uint16_t comp_cpi; /* Compression parameter index */
34 };
35
36 #include "netdissect.h"
37 #include "extract.h"
38
39 void
ipcomp_print(netdissect_options * ndo,register const u_char * bp)40 ipcomp_print(netdissect_options *ndo, register const u_char *bp)
41 {
42 register const struct ipcomp *ipcomp;
43 uint16_t cpi;
44
45 ipcomp = (const struct ipcomp *)bp;
46 ND_TCHECK(*ipcomp);
47 cpi = EXTRACT_16BITS(&ipcomp->comp_cpi);
48
49 ND_PRINT((ndo, "IPComp(cpi=0x%04x)", cpi));
50
51 /*
52 * XXX - based on the CPI, we could decompress the packet here.
53 * Packet buffer management is a headache (if we decompress,
54 * packet will become larger).
55 *
56 * We would decompress the packet and then call a routine that,
57 * based on ipcomp->comp_nxt, dissects the decompressed data.
58 *
59 * Until we do that, however, we just return -1, so that
60 * the loop that processes "protocol"/"next header" types
61 * stops - there's nothing more it can do with a compressed
62 * payload.
63 */
64 return;
65
66 trunc:
67 ND_PRINT((ndo, "[|IPCOMP]"));
68 return;
69 }
70