The Tcpdump Group git mirrors - tcpdump/blob - print-ipcomp.c

   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 #if defined(HAVE_LIBZ) && defined(HAVE_ZLIB_H)
  37 #include <zlib.h>
  38 #endif
  39
  40 #include "netdissect.h"
  41 #include "extract.h"
  42
  43 int
  44 ipcomp_print(netdissect_options *ndo, register const u_char *bp, int *nhdr _U_)
  45 {
  46         register const struct ipcomp *ipcomp;
  47         register const u_char *ep;
  48         uint16_t cpi;
  49 #if defined(HAVE_LIBZ) && defined(HAVE_ZLIB_H)
  50         int advance;
  51 #endif
  52
  53         ipcomp = (const struct ipcomp *)bp;
  54         cpi = EXTRACT_16BITS(&ipcomp->comp_cpi);
  55
  56         /* 'ep' points to the end of available data. */
  57         ep = ndo->ndo_snapend;
  58
  59         if ((const u_char *)(ipcomp + 1) >= ep - sizeof(struct ipcomp)) {
  60                 ND_PRINT((ndo, "[|IPCOMP]"));
  61                 goto fail;
  62         }
  63         ND_PRINT((ndo, "IPComp(cpi=0x%04x)", cpi));
  64
  65 #if defined(HAVE_LIBZ) && defined(HAVE_ZLIB_H)
  66         if (1)
  67                 goto fail;
  68
  69         /*
  70          * We may want to decompress the packet here.  Packet buffer
  71          * management is a headache (if we decompress, packet will become
  72          * larger).
  73          */
  74         if (nhdr)
  75                 *nhdr = ipcomp->comp_nxt;
  76         advance = sizeof(struct ipcomp);
  77
  78         ND_PRINT((ndo, ": "));
  79         return advance;
  80
  81 #endif
  82 fail:
  83         return -1;
  84 }