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 #ifdef HAVE_CONFIG_H
  23 #include "config.h"
  24 #endif
  25
  26 #include <netdissect-stdinc.h>
  27
  28 struct ipcomp {
  29         uint8_t comp_nxt;       /* Next Header */
  30         uint8_t comp_flags;     /* Length of data, in 32bit */
  31         uint16_t comp_cpi;      /* Compression parameter index */
  32 };
  33
  34 #if defined(HAVE_LIBZ) && defined(HAVE_ZLIB_H)
  35 #include <zlib.h>
  36 #endif
  37
  38 #include "netdissect.h"
  39 #include "extract.h"
  40
  41 int
  42 ipcomp_print(netdissect_options *ndo, register const u_char *bp, int *nhdr _U_)
  43 {
  44         register const struct ipcomp *ipcomp;
  45         register const u_char *ep;
  46         uint16_t cpi;
  47 #if defined(HAVE_LIBZ) && defined(HAVE_ZLIB_H)
  48         int advance;
  49 #endif
  50
  51         ipcomp = (const struct ipcomp *)bp;
  52         cpi = EXTRACT_16BITS(&ipcomp->comp_cpi);
  53
  54         /* 'ep' points to the end of available data. */
  55         ep = ndo->ndo_snapend;
  56
  57         if ((const u_char *)(ipcomp + 1) >= ep - sizeof(struct ipcomp)) {
  58                 ND_PRINT((ndo, "[|IPCOMP]"));
  59                 goto fail;
  60         }
  61         ND_PRINT((ndo, "IPComp(cpi=0x%04x)", cpi));
  62
  63 #if defined(HAVE_LIBZ) && defined(HAVE_ZLIB_H)
  64         if (1)
  65                 goto fail;
  66
  67         /*
  68          * We may want to decompress the packet here.  Packet buffer
  69          * management is a headache (if we decompress, packet will become
  70          * larger).
  71          */
  72         if (nhdr)
  73                 *nhdr = ipcomp->comp_nxt;
  74         advance = sizeof(struct ipcomp);
  75
  76         ND_PRINT((ndo, ": "));
  77         return advance;
  78
  79 #endif
  80 fail:
  81         return -1;
  82 }