epan/tvbuff-int.h

   1 /** @file
   2  *
   3  * Structures that most TVB users should not be accessing directly.
   4  *
   5  * Wireshark - Network traffic analyzer
   6  * By Gerald Combs <gerald@wireshark.org>
   7  * Copyright 1998 Gerald Combs
   8  *
   9  * SPDX-License-Identifier: GPL-2.0-or-later
  10  */
  11
  12 #ifndef __TVBUFF_INT_H__
  13 #define __TVBUFF_INT_H__
  14
  15 struct tvbuff;
  16
  17 struct tvb_ops {
  18         size_t tvb_size;
  19         void (*tvb_free)(struct tvbuff *tvb);
  20         unsigned (*tvb_offset)(const struct tvbuff *tvb, unsigned counter);
  21         const uint8_t *(*tvb_get_ptr)(struct tvbuff *tvb, unsigned abs_offset, unsigned abs_length);
  22         void *(*tvb_memcpy)(struct tvbuff *tvb, void *target, unsigned offset, unsigned length);
  23
  24         int (*tvb_find_uint8)(tvbuff_t *tvb, unsigned abs_offset, unsigned limit, uint8_t needle);
  25         int (*tvb_ws_mempbrk_pattern_uint8)(tvbuff_t *tvb, unsigned abs_offset, unsigned limit, const ws_mempbrk_pattern* pattern, unsigned char *found_needle);
  26
  27         tvbuff_t *(*tvb_clone)(tvbuff_t *tvb, unsigned abs_offset, unsigned abs_length);
  28 };
  29
  30 /*
  31  * Tvbuff flags.
  32  */
  33 #define TVBUFF_FRAGMENT         0x00000001      /* this is a fragment */
  34
  35 struct tvbuff {
  36         /* Doubly linked list pointers */
  37         tvbuff_t                *next;
  38
  39         /* Record-keeping */
  40         const struct tvb_ops   *ops;
  41         bool            initialized;
  42         unsigned                        flags;
  43         struct tvbuff           *ds_tvb;  /**< data source top-level tvbuff */
  44
  45         /** Pointer to the data for this tvbuff.
  46          * It might be null, which either means that 1) it's a
  47          * zero-length tvbuff or 2) the tvbuff was lazily
  48          * constructed, so that we don't allocate a buffer of
  49          * backing data and fill it in unless we need that
  50          * data, e.g. when tvb_get_ptr() is called.
  51          */
  52         const uint8_t           *real_data;
  53
  54         /** Amount of data that's available from the capture
  55          * file.  This is the length of virtual buffer (and/or
  56          * real_data).  It may be less than the reported
  57          * length if this is from a packet that was cut short
  58          * by the capture process.
  59          *
  60          * This must never be > reported_length or contained_length. */
  61         unsigned                        length;
  62
  63         /** Amount of data that was reported as being in
  64          * the packet or other data that this represents.
  65          * As indicated above, it may be greater than the
  66          * amount of data that's available. */
  67         unsigned                        reported_length;
  68
  69         /** If this was extracted from a parent tvbuff,
  70          * this is the amount of extracted data that
  71          * was reported as being in the parent tvbuff;
  72          * if this represents a blob of data in that
  73          * tvbuff that has a length specified by data
  74          * in that tvbuff, it might be greater than
  75          * the amount of data that was actually there
  76          * to extract, so it could be greater than
  77          * reported_length.
  78          *
  79          * If this wasn't extracted from a parent tvbuff,
  80          * this is the same as reported_length.
  81          *
  82          * This must never be > reported_length. */
  83         unsigned                        contained_length;
  84
  85         /* Offset from beginning of first "real" tvbuff. */
  86         int                     raw_offset;
  87 };
  88
  89 WS_DLL_PUBLIC tvbuff_t *tvb_new(const struct tvb_ops *ops);
  90
  91 tvbuff_t *tvb_new_proxy(tvbuff_t *backing);
  92
  93 void tvb_add_to_chain(tvbuff_t *parent, tvbuff_t *child);
  94
  95 unsigned tvb_offset_from_real_beginning_counter(const tvbuff_t *tvb, const unsigned counter);
  96
  97 void tvb_check_offset_length(const tvbuff_t *tvb, const int offset, int const length_val, unsigned *offset_ptr, unsigned *length_ptr);
  98 #endif