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 1.8 2024/09/02 16:15:31 christos Exp $"); 25 #endif 26 27 /* \summary: IP Payload Compression Protocol (IPComp) printer */ 28 29 #include <config.h> 30 31 #include "netdissect-stdinc.h" 32 33 #include "netdissect.h" 34 #include "extract.h" 35 36 struct ipcomp { 37 nd_uint8_t comp_nxt; /* Next Header */ 38 nd_uint8_t comp_flags; /* Length of data, in 32bit */ 39 nd_uint16_t comp_cpi; /* Compression parameter index */ 40 }; 41 42 void 43 ipcomp_print(netdissect_options *ndo, const u_char *bp) 44 { 45 const struct ipcomp *ipcomp; 46 uint16_t cpi; 47 48 ndo->ndo_protocol = "ipcomp"; 49 ipcomp = (const struct ipcomp *)bp; 50 cpi = GET_BE_U_2(ipcomp->comp_cpi); 51 52 ND_PRINT("IPComp(cpi=0x%04x)", cpi); 53 54 /* 55 * XXX - based on the CPI, we could decompress the packet here. 56 * Packet buffer management is a headache (if we decompress, 57 * packet will become larger). 58 * 59 * We would decompress the packet and then call a routine that, 60 * based on ipcomp->comp_nxt, dissects the decompressed data. 61 * 62 * Until we do that, however, we just return -1, so that 63 * the loop that processes "protocol"/"next header" types 64 * stops - there's nothing more it can do with a compressed 65 * payload. 66 */ 67 } 68