epan/tvbuff_snappy.c

   1 /* tvbuff_snappy.c
   2  *
   3  * Wireshark - Network traffic analyzer
   4  * By Gerald Combs <gerald@wireshark.org>
   5  * Copyright 1998 Gerald Combs
   6  *
   7  * SPDX-License-Identifier: GPL-2.0-or-later
   8  */
   9
  10 #include <config.h>
  11
  12 #ifdef HAVE_SNAPPY
  13 #include <snappy-c.h>
  14 #endif
  15
  16 #include "tvbuff.h"
  17
  18 #ifdef HAVE_SNAPPY
  19
  20 /*
  21  * Uncompresses a snappy compressed packet inside a message of tvb at offset with
  22  * length comprlen.  Returns an uncompressed tvbuffer if uncompression
  23  * succeeded or NULL if uncompression failed.
  24  */
  25
  26 tvbuff_t *
  27 tvb_uncompress_snappy(tvbuff_t *tvb, const int offset, int comprlen)
  28 {
  29     tvbuff_t *uncompr_tvb = NULL;
  30     unsigned char *decompressed_buffer = NULL;
  31     size_t orig_size = 0;
  32     snappy_status ret;
  33     const void *compr_ptr;
  34
  35     if (tvb == NULL || comprlen <= 0 || comprlen > tvb_captured_length_remaining(tvb, offset)) {
  36         return NULL;
  37     }
  38
  39     compr_ptr = tvb_get_ptr(tvb, offset, comprlen);
  40     ret = snappy_uncompressed_length(compr_ptr, comprlen, &orig_size);
  41
  42     if (ret == SNAPPY_OK) {
  43         decompressed_buffer = (unsigned char *)g_malloc(orig_size);
  44
  45         ret = snappy_uncompress(compr_ptr, comprlen, decompressed_buffer, &orig_size);
  46
  47         if (ret == SNAPPY_OK) {
  48             uncompr_tvb = tvb_new_real_data(decompressed_buffer, (uint32_t)orig_size, (uint32_t)orig_size);
  49             tvb_set_free_cb(uncompr_tvb, g_free);
  50         } else {
  51             g_free(decompressed_buffer);
  52         }
  53     }
  54
  55     return uncompr_tvb;
  56 }
  57 #else
  58 tvbuff_t *
  59 tvb_uncompress_snappy(tvbuff_t *tvb _U_, const int offset _U_, int comprlen _U_)
  60 {
  61     return NULL;
  62 }
  63 #endif
  64
  65 tvbuff_t *
  66 tvb_child_uncompress_snappy(tvbuff_t *parent, tvbuff_t *tvb, const int offset, int comprlen)
  67 {
  68     tvbuff_t *new_tvb = tvb_uncompress_snappy(tvb, offset, comprlen);
  69     if (new_tvb)
  70         tvb_set_child_real_data_tvbuff(parent, new_tvb);
  71     return new_tvb;
  72 }
  73
  74 /*
  75  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
  76  *
  77  * Local variables:
  78  * c-basic-offset: 4
  79  * tab-width: 8
  80  * indent-tabs-mode: nil
  81  * End:
  82  *
  83  * vi: set shiftwidth=4 tabstop=8 expandtab:
  84  * :indentSize=4:tabSize=8:noTabs=true:
  85  */