epan/tvbuff.h

   1 /* tvbuff.h
   2  *
   3  * Testy, Virtual(-izable) Buffer of guint8*'s
   4  *
   5  * "Testy" -- the buffer gets mad when an attempt is made to access data
   6  *      beyond the bounds of the buffer. An exception is thrown.
   7  *
   8  * "Virtual" -- the buffer can have its own data, can use a subset of
   9  *      the data of a backing tvbuff, or can be a composite of
  10  *      other tvbuffs.
  11  *
  12  * $Id$
  13  *
  14  * Copyright (c) 2000 by Gilbert Ramirez <gram@alumni.rice.edu>
  15  *
  16  * Wireshark - Network traffic analyzer
  17  * By Gerald Combs <gerald@wireshark.org>
  18  * Copyright 1998 Gerald Combs
  19  *
  20  * This program is free software; you can redistribute it and/or
  21  * modify it under the terms of the GNU General Public License
  22  * as published by the Free Software Foundation; either version 2
  23  * of the License, or (at your option) any later version.
  24  *
  25  * This program is distributed in the hope that it will be useful,
  26  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  27  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  28  * GNU General Public License for more details.
  29  *
  30  * You should have received a copy of the GNU General Public License
  31  * along with this program; if not, write to the Free Software
  32  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  33  */
  34
  35 #ifndef __TVBUFF_H__
  36 #define __TVBUFF_H__
  37
  38 #include <glib.h>
  39 #include <epan/guid-utils.h>
  40 #include <epan/wmem/wmem.h>
  41
  42 #ifdef __cplusplus
  43 extern "C" {
  44 #endif /* __cplusplus */
  45
  46 /** @file
  47  * "testy, virtual(-izable) buffer".  They are testy in that they get mad when
  48  * an attempt is made to access data beyond the bounds of their array. In that
  49  * case, they throw an exception.
  50  *
  51  * They are virtualizable in that new tvbuff's can be made from other tvbuffs,
  52  * while only the original tvbuff may have data. That is, the new tvbuff has
  53  * virtual data.
  54  */
  55
  56 struct tvbuff;
  57 typedef struct tvbuff tvbuff_t;
  58
  59 struct e_in6_addr; /* ipv6-utils.h */
  60
  61 /** @defgroup tvbuff Testy, Virtual(-izable) Buffers
  62  *
  63  * Dissector use and management
  64  *
  65  *  Consider a collection of tvbs as being a chain or stack of tvbs.
  66  *
  67  *  When dissecting a frame:
  68  *   The top-level dissector (packet.c) pushes the initial tvb (containing
  69  *   the complete frame) onto the stack (starts the chain) and then calls
  70  *   a sub-dissector which in turn calls the next sub-dissector and so on.
  71  *   Each sub-dissector may chain additional tvbs (see below) to the tvb
  72  *   handed to that dissector. After dissection is complete and control has
  73  *   returned to the top-level dissector, the chain of tvbs (stack) is free'd
  74  *   via a call to tvb_free_chain() (in epan_dissect_cleanup()).
  75  *
  76  * A dissector:
  77  *  - Can chain new tvbs (subset, real, composite) to the
  78  *    tvb handed to the dissector using tvb_new_subset(),
  79  *    tvb_new_subset_length(), tvb_new_subset_remaining(),
  80  *    tvb_new_child_real_data(), tvb_set_child_real_data_tvbuff(),
  81  *    tvb_composite_finalize(), and tvb_child_uncompress(). (Composite
  82  *    tvbs should reference only tvbs which are already part of the chain).
  83  *  - Must not save for later use (e.g., when dissecting another frame) a
  84  *    pointer to a tvb handed to the dissector; (A higher level function
  85  *    may very well free the chain thus leaving a dangling pointer).
  86  *    This (obviously) also applies to any tvbs chained to the tvb handed
  87  *    to the dissector.
  88  *  - Can create its own tvb chain (using tvb_new_real_data() which the
  89  *
  90  *    dissector is free to manage as desired.
  91  * @{
  92  */
  93
  94 /** TVBUFF_REAL_DATA contains a guint8* that points to real data.
  95  * The data is allocated and contiguous.
  96  *
  97  * TVBUFF_SUBSET has a backing tvbuff. The TVBUFF_SUBSET is a "window"
  98  * through which the program sees only a portion of the backing tvbuff.
  99  *
 100  * TVBUFF_COMPOSITE combines multiple tvbuffs sequentially to produce
 101  * a larger byte array.
 102  *
 103  * tvbuff's of any type can be used as the backing-tvbuff of a
 104  * TVBUFF_SUBSET or as the member of a TVBUFF_COMPOSITE.
 105  * TVBUFF_COMPOSITEs can have member-tvbuffs of different types.
 106  *
 107  * Once a tvbuff is create/initialized/finalized, the tvbuff is read-only.
 108  * That is, it cannot point to any other data. A new tvbuff must be created if
 109  * you want a tvbuff that points to other data.
 110  *
 111  * tvbuff's are normally chained together to allow efficient de-allocation of
 112  * tvbuff's.
 113  */
 114
 115 typedef void (*tvbuff_free_cb_t)(void*);
 116
 117 /** Extracts 'number of bits' starting at 'bit offset'.
 118  * Returns a pointer to a newly initialized g_malloc'd REAL_DATA
 119  * tvbuff with the bits octet aligned.
 120  */
 121 WS_DLL_PUBLIC tvbuff_t *tvb_new_octet_aligned(tvbuff_t *tvb,
 122     guint32 bit_offset, gint32 no_of_bits);
 123
 124 WS_DLL_PUBLIC tvbuff_t *tvb_new_chain(tvbuff_t *parent, tvbuff_t *backing);
 125
 126 WS_DLL_PUBLIC tvbuff_t *tvb_clone(tvbuff_t *tvb);
 127
 128 WS_DLL_PUBLIC tvbuff_t *tvb_clone_offset_len(tvbuff_t *tvb, guint offset,
 129     guint len);
 130
 131 /** Free a tvbuff_t and all tvbuffs chained from it
 132  * The tvbuff must be 'the 'head' (initial) tvb of a chain or
 133  * must not be in a chain.
 134  * If specified, a callback to free the tvbuff data will be invoked
 135  * for each tvbuff free'd */
 136 WS_DLL_PUBLIC void tvb_free(tvbuff_t *tvb);
 137
 138 /** Free the tvbuff_t and all tvbuffs chained from it.
 139  * The tvbuff must be 'the 'head' (initial) tvb of a chain or
 140  * must not be in a chain.
 141  * If specified, a callback to free the tvbuff data will be invoked
 142  * for each tvbuff free'd */
 143 WS_DLL_PUBLIC void tvb_free_chain(tvbuff_t *tvb);
 144
 145 /** Set a callback function to call when a tvbuff is actually freed
 146  * One argument is passed to that callback --- a void* that points
 147  * to the real data. Obviously, this only applies to a
 148  * TVBUFF_REAL_DATA tvbuff. */
 149 WS_DLL_PUBLIC void tvb_set_free_cb(tvbuff_t *tvb, const tvbuff_free_cb_t func);
 150
 151 /** Attach a TVBUFF_REAL_DATA tvbuff to a parent tvbuff. This connection
 152  * is used during a tvb_free_chain()... the "child" TVBUFF_REAL_DATA acts
 153  * as if is part of the chain-of-creation of the parent tvbuff, although it
 154  * isn't. This is useful if you need to take the data from some tvbuff,
 155  * run some operation on it, like decryption or decompression, and make a new
 156  * tvbuff from it, yet want the new tvbuff to be part of the chain. The reality
 157  * is that the new tvbuff *is* part of the "chain of creation", but in a way
 158  * that these tvbuff routines are ignorant of. Use this function to make
 159  * the tvbuff routines knowledgable of this fact. */
 160 WS_DLL_PUBLIC void tvb_set_child_real_data_tvbuff(tvbuff_t *parent,
 161     tvbuff_t *child);
 162
 163 WS_DLL_PUBLIC tvbuff_t *tvb_new_child_real_data(tvbuff_t *parent,
 164     const guint8 *data, const guint length, const gint reported_length);
 165
 166 /** Create a tvbuff backed by existing data. Can throw ReportedBoundsError.
 167  * Normally, a callback to free the data should be registered using
 168  * tvb_set_free_cb(); when this tvbuff is freed, then your callback will be
 169  * called, and at that time you can free your original data. */
 170 WS_DLL_PUBLIC tvbuff_t *tvb_new_real_data(const guint8 *data,
 171     const guint length, const gint reported_length);
 172
 173 /** Create a tvbuff that's a subset of another tvbuff.
 174  *
 175  * 'backing_offset', if positive, is the offset from the beginning of
 176  * the backing tvbuff at which the new tvbuff's data begins, and, if
 177  * negative, is the offset from the end of the backing tvbuff at which
 178  * the new tvbuff's data begins.
 179  *
 180  * 'backing_length' is the length of the data to include in the new
 181  * tvbuff, starting with the byte at 'backing_offset"; if -1, it
 182  * means "to the end of the backing tvbuff".  It can be 0, although
 183  * the usefulness of the buffer would be rather limited.
 184  *
 185  * Will throw BoundsError if 'backing_offset'/'length'
 186  * is beyond the bounds of the backing tvbuff.
 187  * Can throw ReportedBoundsError. */
 188 WS_DLL_PUBLIC tvbuff_t *tvb_new_subset(tvbuff_t *backing,
 189     const gint backing_offset, const gint backing_length,
 190     const gint reported_length);
 191
 192 /**
 193  * Similar to tvb_new_subset() but with captured length calculated
 194  * to fit within the existing captured length and the specified
 195  * backing length (which is used as the reported length).
 196  * Can throw ReportedBoundsError. */
 197 WS_DLL_PUBLIC tvbuff_t *tvb_new_subset_length(tvbuff_t *backing,
 198     const gint backing_offset, const gint backing_length);
 199
 200 /** Similar to tvb_new_subset() but with backing_length and reported_length set
 201  * to -1.  Can throw ReportedBoundsError. */
 202 WS_DLL_PUBLIC tvbuff_t *tvb_new_subset_remaining(tvbuff_t *backing,
 203     const gint backing_offset);
 204
 205 /*
 206 * Both tvb_composite_append and tvb_composite_prepend can throw
 207  * BoundsError if member_offset/member_length goes beyond bounds of
 208  * the 'member' tvbuff. */
 209
 210 /** Append to the list of tvbuffs that make up this composite tvbuff */
 211 WS_DLL_PUBLIC void tvb_composite_append(tvbuff_t *tvb, tvbuff_t *member);
 212
 213 /** Prepend to the list of tvbuffs that make up this composite tvbuff */
 214 extern void tvb_composite_prepend(tvbuff_t *tvb, tvbuff_t *member);
 215
 216 /** Create an empty composite tvbuff. */
 217 WS_DLL_PUBLIC tvbuff_t *tvb_new_composite(void);
 218
 219 /** Mark a composite tvbuff as initialized. No further appends or prepends
 220  * occur, data access can finally happen after this finalization. */
 221 WS_DLL_PUBLIC void tvb_composite_finalize(tvbuff_t *tvb);
 222
 223
 224 /* Get total length of buffer */
 225 WS_DLL_PUBLIC guint tvb_length(const tvbuff_t *tvb);
 226
 227 /** Computes bytes to end of buffer, from offset (which can be negative,
 228  * to indicate bytes from end of buffer). Function returns 0 if offset is
 229  * either at the end of the buffer or out of bounds. No exception is thrown. */
 230 WS_DLL_PUBLIC gint tvb_length_remaining(const tvbuff_t *tvb, const gint offset);
 231
 232 /** Same as above, but throws an exception if the offset is out of bounds. */
 233 WS_DLL_PUBLIC guint tvb_ensure_length_remaining(const tvbuff_t *tvb,
 234     const gint offset);
 235
 236 /* Checks (w/o throwing exception) that the bytes referred to by
 237  * 'offset'/'length' actually exist in the buffer */
 238 WS_DLL_PUBLIC gboolean tvb_bytes_exist(const tvbuff_t *tvb, const gint offset,
 239     const gint length);
 240
 241 /** Checks that the bytes referred to by 'offset'/'length' actually exist
 242  * in the buffer, and throws an exception if they aren't. */
 243 WS_DLL_PUBLIC void tvb_ensure_bytes_exist(const tvbuff_t *tvb,
 244     const gint offset, const gint length);
 245
 246 /* Checks (w/o throwing exception) that offset exists in buffer */
 247 WS_DLL_PUBLIC gboolean tvb_offset_exists(const tvbuff_t *tvb,
 248     const gint offset);
 249
 250 /* Get reported length of buffer */
 251 WS_DLL_PUBLIC guint tvb_reported_length(const tvbuff_t *tvb);
 252
 253 /** Computes bytes of reported packet data to end of buffer, from offset
 254  * (which can be negative, to indicate bytes from end of buffer). Function
 255  * returns 0 if offset is either at the end of the buffer or out of bounds.
 256  * No exception is thrown. */
 257 WS_DLL_PUBLIC gint tvb_reported_length_remaining(const tvbuff_t *tvb,
 258     const gint offset);
 259
 260 /** Set the reported length of a tvbuff to a given value; used for protocols
 261    whose headers contain an explicit length and where the calling
 262    dissector's payload may include padding as well as the packet for
 263    this protocol.
 264
 265    Also adjusts the data length. */
 266 WS_DLL_PUBLIC void tvb_set_reported_length(tvbuff_t *tvb, const guint);
 267
 268 WS_DLL_PUBLIC guint tvb_offset_from_real_beginning(const tvbuff_t *tvb);
 269
 270 /* Returns the offset from the first byte of real data. */
 271 WS_DLL_PUBLIC gint tvb_raw_offset(tvbuff_t *tvb);
 272
 273 /** Set the "this is a fragment" flag. */
 274 WS_DLL_PUBLIC void tvb_set_fragment(tvbuff_t *tvb);
 275
 276 WS_DLL_PUBLIC struct tvbuff *tvb_get_ds_tvb(tvbuff_t *tvb);
 277
 278
 279 /************** START OF ACCESSORS ****************/
 280 /* All accessors will throw an exception if appropriate */
 281
 282 WS_DLL_PUBLIC guint8 tvb_get_guint8(tvbuff_t *tvb, const gint offset);
 283
 284 WS_DLL_PUBLIC guint16 tvb_get_ntohs(tvbuff_t *tvb, const gint offset);
 285 WS_DLL_PUBLIC guint32 tvb_get_ntoh24(tvbuff_t *tvb, const gint offset);
 286 WS_DLL_PUBLIC guint32 tvb_get_ntohl(tvbuff_t *tvb, const gint offset);
 287 WS_DLL_PUBLIC guint64 tvb_get_ntoh40(tvbuff_t *tvb, const gint offset);
 288 WS_DLL_PUBLIC guint64 tvb_get_ntoh48(tvbuff_t *tvb, const gint offset);
 289 WS_DLL_PUBLIC guint64 tvb_get_ntoh56(tvbuff_t *tvb, const gint offset);
 290 WS_DLL_PUBLIC guint64 tvb_get_ntoh64(tvbuff_t *tvb, const gint offset);
 291 WS_DLL_PUBLIC gfloat tvb_get_ntohieee_float(tvbuff_t *tvb, const gint offset);
 292 WS_DLL_PUBLIC gdouble tvb_get_ntohieee_double(tvbuff_t *tvb,
 293     const gint offset);
 294
 295 WS_DLL_PUBLIC guint16 tvb_get_letohs(tvbuff_t *tvb, const gint offset);
 296 WS_DLL_PUBLIC guint32 tvb_get_letoh24(tvbuff_t *tvb, const gint offset);
 297 WS_DLL_PUBLIC guint32 tvb_get_letohl(tvbuff_t *tvb, const gint offset);
 298 WS_DLL_PUBLIC guint64 tvb_get_letoh40(tvbuff_t *tvb, const gint offset);
 299 WS_DLL_PUBLIC guint64 tvb_get_letoh48(tvbuff_t *tvb, const gint offset);
 300 WS_DLL_PUBLIC guint64 tvb_get_letoh56(tvbuff_t *tvb, const gint offset);
 301 WS_DLL_PUBLIC guint64 tvb_get_letoh64(tvbuff_t *tvb, const gint offset);
 302 WS_DLL_PUBLIC gfloat tvb_get_letohieee_float(tvbuff_t *tvb, const gint offset);
 303 WS_DLL_PUBLIC gdouble tvb_get_letohieee_double(tvbuff_t *tvb,
 304     const gint offset);
 305
 306 /**
 307  * Fetch an IPv4 address, in network byte order.
 308  * We do *not* convert it to host byte order; we leave it in
 309  * network byte order, as that's what its callers expect. */
 310 WS_DLL_PUBLIC guint32 tvb_get_ipv4(tvbuff_t *tvb, const gint offset);
 311
 312 /* Fetch an IPv6 address. */
 313 WS_DLL_PUBLIC void tvb_get_ipv6(tvbuff_t *tvb, const gint offset,
 314     struct e_in6_addr *addr);
 315
 316 /* Fetch a GUID. */
 317 WS_DLL_PUBLIC void tvb_get_ntohguid(tvbuff_t *tvb, const gint offset,
 318     e_guid_t *guid);
 319 WS_DLL_PUBLIC void tvb_get_letohguid(tvbuff_t *tvb, const gint offset,
 320     e_guid_t *guid);
 321 WS_DLL_PUBLIC void tvb_get_guid(tvbuff_t *tvb, const gint offset,
 322     e_guid_t *guid, const guint representation);
 323
 324 /* Fetch a specified number of bits from bit offset in a tvb.  All of these
 325  * functions are equivalent, except for the type of the return value.  Note
 326  * that the parameter encoding (where supplied) is meaningless and ignored */
 327
 328 /* get 1 - 8 bits returned in a guint8 */
 329 WS_DLL_PUBLIC guint8 tvb_get_bits8(tvbuff_t *tvb, guint bit_offset,
 330     const gint no_of_bits);
 331 /* get 1 - 16 bits returned in a guint16 */
 332 WS_DLL_PUBLIC guint16 tvb_get_bits16(tvbuff_t *tvb, guint bit_offset,
 333     const gint no_of_bits, const guint encoding);
 334 /* get 1 - 32 bits returned in a guint32 */
 335 WS_DLL_PUBLIC guint32 tvb_get_bits32(tvbuff_t *tvb, guint bit_offset,
 336     const gint no_of_bits, const guint encoding);
 337 /* get 1 - 64 bits returned in a guint64 */
 338 WS_DLL_PUBLIC guint64 tvb_get_bits64(tvbuff_t *tvb, guint bit_offset,
 339     const gint no_of_bits, const guint encoding);
 340
 341 /**
 342  *  This function has EXACTLY the same behavior as
 343  *  tvb_get_bits32()
 344  */
 345 WS_DLL_PUBLIC guint32 tvb_get_bits(tvbuff_t *tvb, const guint bit_offset,
 346     const gint no_of_bits, const guint encoding);
 347
 348 /** Returns target for convenience. Does not suffer from possible
 349  * expense of tvb_get_ptr(), since this routine is smart enough
 350  * to copy data in chunks if the request range actually exists in
 351  * different TVBUFF_REAL_DATA tvbuffs. This function assumes that the
 352  * target memory is already allocated; it does not allocate or free the
 353  * target memory. */
 354 WS_DLL_PUBLIC void *tvb_memcpy(tvbuff_t *tvb, void *target, const gint offset,
 355     size_t length);
 356
 357 /** If scope is set to NULL it is the user's responsibility to g_free()
 358  * the memory allocated by tvb_memdup(). Otherwise memory is
 359  * automatically freed when the scope lifetime is reached.
 360  * Calls tvb_memcpy() */
 361 WS_DLL_PUBLIC void *tvb_memdup(wmem_allocator_t *scope, tvbuff_t *tvb,
 362     const gint offset, size_t length);
 363
 364 /** WARNING! This function is possibly expensive, temporarily allocating
 365  * another copy of the packet data. Furthermore, it's dangerous because once
 366  * this pointer is given to the user, there's no guarantee that the user will
 367  * honor the 'length' and not overstep the boundaries of the buffer.
 368  *
 369  * If you're thinking of using tvb_get_ptr, STOP WHAT YOU ARE DOING
 370  * IMMEDIATELY. Go take a break. Consider that tvb_get_ptr hands you
 371  * a raw, unprotected pointer that you can easily use to create a
 372  * security vulnerability or otherwise crash Wireshark. Then consider
 373  * that you can probably find a function elsewhere in this file that
 374  * does exactly what you want in a much more safe and robust manner.
 375  *
 376  * The returned pointer is data that is internal to the tvbuff, so do not
 377  * attempt to free it. Don't modify the data, either, because another tvbuff
 378  * that might be using this tvbuff may have already copied that portion of
 379  * the data (sometimes tvbuff's need to make copies of data, but that's the
 380  * internal implementation that you need not worry about). Assume that the
 381  * guint8* points to read-only data that the tvbuff manages.
 382  *
 383  * Return a pointer into our buffer if the data asked for via 'offset'/'length'
 384  * is contiguous (which might not be the case for TVBUFF_COMPOSITE). If the
 385  * data is not contiguous, a tvb_memdup() is called for the entire buffer
 386  * and the pointer to the newly-contiguous data is returned. This dynamically-
 387  * allocated memory will be freed when the tvbuff is freed, after the
 388  * tvbuff_free_cb_t() is called, if any. */
 389 WS_DLL_PUBLIC const guint8 *tvb_get_ptr(tvbuff_t *tvb, const gint offset,
 390     const gint length);
 391
 392 /** Find first occurrence of needle in tvbuff, starting at offset. Searches
 393  * at most maxlength number of bytes; if maxlength is -1, searches to
 394  * end of tvbuff.
 395  * Returns the offset of the found needle, or -1 if not found.
 396  * Will not throw an exception, even if maxlength exceeds boundary of tvbuff;
 397  * in that case, -1 will be returned if the boundary is reached before
 398  * finding needle. */
 399 WS_DLL_PUBLIC gint tvb_find_guint8(tvbuff_t *tvb, const gint offset,
 400     const gint maxlength, const guint8 needle);
 401
 402 /** Find first occurrence of any of the needles in tvbuff, starting at offset.
 403  * Searches at most maxlength number of bytes. Returns the offset of the
 404  * found needle, or -1 if not found and the found needle.
 405  * Will not throw an exception, even if
 406  * maxlength exceeds boundary of tvbuff; in that case, -1 will be returned if
 407  * the boundary is reached before finding needle. */
 408 WS_DLL_PUBLIC gint tvb_pbrk_guint8(tvbuff_t *tvb, const gint offset,
 409     const gint maxlength, const guint8 *needles, guchar *found_needle);
 410
 411 /** Find size of stringz (NUL-terminated string) by looking for terminating
 412  * NUL.  The size of the string includes the terminating NUL.
 413  *
 414  * If the NUL isn't found, it throws the appropriate exception.
 415  */
 416 WS_DLL_PUBLIC guint tvb_strsize(tvbuff_t *tvb, const gint offset);
 417
 418 /** Find size of UCS-2 or UTF-16 stringz (NUL-terminated string) by
 419  * looking for terminating 16-bit NUL.  The size of the string includes
 420  * the terminating NUL.
 421  *
 422  * If the NUL isn't found, it throws the appropriate exception.
 423  */
 424 WS_DLL_PUBLIC guint tvb_unicode_strsize(tvbuff_t *tvb, const gint offset);
 425
 426 /** Find length of string by looking for end of zero terminated string, up to
 427  * 'maxlength' characters'; if 'maxlength' is -1, searches to end
 428  * of tvbuff.
 429  * Returns -1 if 'maxlength' reached before finding EOS. */
 430 WS_DLL_PUBLIC gint tvb_strnlen(tvbuff_t *tvb, const gint offset,
 431     const guint maxlength);
 432
 433 /** Convert a string from Unicode to ASCII.  At the moment we fake it by
 434  * assuming all characters are ASCII  )-:  The len parameter is the number
 435  * of guint16's to convert from Unicode.
 436  *
 437  * XXX - These functions have been superceded by tvb_get_unicode_string()
 438  *
 439  * If scope is set to NULL, returned buffer is allocated by g_malloc()
 440  * and must be g_free by the caller. Otherwise memory is automatically
 441  * freed when the scope lifetime is reached.
 442  */
 443 WS_DLL_PUBLIC char *tvb_get_faked_unicode(wmem_allocator_t *scope,
 444     tvbuff_t *tvb, int offset, const int len, const gboolean little_endian);
 445
 446 /**
 447  * Format the data in the tvb from offset for size ...
 448  */
 449 WS_DLL_PUBLIC gchar *tvb_format_text(tvbuff_t *tvb, const gint offset,
 450     const gint size);
 451
 452 /**
 453  * Like "tvb_format_text()", but for 'wsp'; don't show
 454  * the characters as C-style escapes.
 455  */
 456 WS_DLL_PUBLIC gchar *tvb_format_text_wsp(tvbuff_t *tvb, const gint offset,
 457     const gint size);
 458
 459 /**
 460  * Like "tvb_format_text()", but for null-padded strings; don't show
 461  * the null padding characters as "\000".
 462  */
 463 extern gchar *tvb_format_stringzpad(tvbuff_t *tvb, const gint offset,
 464     const gint size);
 465
 466 /**
 467  * Like "tvb_format_text_wsp()", but for null-padded strings; don't show
 468  * the null padding characters as "\000".
 469  */
 470 extern gchar *tvb_format_stringzpad_wsp(tvbuff_t *tvb, const gint offset,
 471     const gint size);
 472
 473
 474 /**
 475  * Given a tvbuff, an offset, and a length, allocate a buffer big enough
 476  * to hold a non-null-terminated string of that length at that offset,
 477  * plus a trailing zero, copy the string into it, and return a pointer
 478  * to the string.
 479  *
 480  * Throws an exception if the tvbuff ends before the string does.
 481  *
 482  * tvb_get_string() returns a string allocated.
 483  *
 484  * tvb_get_unicode_string() Unicode (UTF-16) version of above.
 485  *
 486  * tvb_get_string_enc() takes a string encoding as well, and converts to UTF-8
 487  *                   from the encoding (only UTF-8 and EBCDIC supported).
 488  *
 489  * If scope is set to NULL it is the user's responsibility to g_free()
 490  * the memory allocated by tvb_memdup(). Otherwise memory is
 491  * automatically freed when the scope lifetime is reached.
 492  */
 493 WS_DLL_PUBLIC guint8 *tvb_get_string(wmem_allocator_t *scope, tvbuff_t *tvb,
 494     const gint offset, const gint length);
 495 WS_DLL_PUBLIC gchar  *tvb_get_unicode_string(wmem_allocator_t *scope,
 496     tvbuff_t *tvb, const gint offset, gint length, const guint encoding);
 497 WS_DLL_PUBLIC guint8 *tvb_get_string_enc(wmem_allocator_t *scope,
 498     tvbuff_t *tvb, const gint offset, const gint length, const guint encoding);
 499
 500
 501 /**
 502  * Given a tvbuff and an offset, with the offset assumed to refer to
 503  * a null-terminated string, find the length of that string (and throw
 504  * an exception if the tvbuff ends before we find the null), allocate
 505  * a buffer big enough to hold the string, copy the string into it,
 506  * and return a pointer to the string.  Also return the length of the
 507  * string (including the terminating null) through a pointer.
 508  *
 509  * tvb_get_stringz() returns a string
 510  *
 511  * tvb_get_stringz_enc() takes a string encoding as well, and converts to
 512  *                   UTF-8 from the encoding (only UTF-8 and EBCDIC supported)
 513  *
 514  * tvb_get_const_stringz() returns a constant (unmodifiable) string that does
 515  *                   not need to be freed, instead it will automatically be
 516  *                   freed once the next packet is dissected.  It is slightly
 517  *                   more efficient than the other routines.
 518  *
 519  * tvb_get_unicode_stringz() Unicode (UTF-16) version of above
 520  *
 521  * If scope is set to NULL it is the user's responsibility to g_free()
 522  * the memory allocated by tvb_memdup(). Otherwise memory is
 523  * automatically freed when the scope lifetime is reached.
 524  */
 525 WS_DLL_PUBLIC guint8 *tvb_get_stringz(wmem_allocator_t *scope, tvbuff_t *tvb,
 526     const gint offset, gint *lengthp);
 527 WS_DLL_PUBLIC guint8 *tvb_get_stringz_enc(wmem_allocator_t *scope,
 528     tvbuff_t *tvb, const gint offset, gint *lengthp, const guint encoding);
 529 WS_DLL_PUBLIC const guint8 *tvb_get_const_stringz(tvbuff_t *tvb,
 530     const gint offset, gint *lengthp);
 531 WS_DLL_PUBLIC gchar *tvb_get_unicode_stringz(wmem_allocator_t *scope,
 532     tvbuff_t *tvb, const gint offset, gint *lengthp, const guint encoding);
 533
 534 /** Looks for a stringz (NUL-terminated string) in tvbuff and copies
 535  * no more than bufsize number of bytes, including terminating NUL, to buffer.
 536  * Returns length of string (not including terminating NUL), or -1 if the
 537  * string was truncated in the buffer due to not having reached the terminating
 538  * NUL.  In this way, it acts like g_snprintf().
 539  *
 540  * When processing a packet where the remaining number of bytes is less
 541  * than bufsize, an exception is not thrown if the end of the packet
 542  * is reached before the NUL is found. If no NUL is found before reaching
 543  * the end of the short packet, -1 is still returned, and the string
 544  * is truncated with a NUL, albeit not at buffer[bufsize - 1], but
 545  * at the correct spot, terminating the string.
 546  */
 547 WS_DLL_PUBLIC gint tvb_get_nstringz(tvbuff_t *tvb, const gint offset,
 548     const guint bufsize, guint8 *buffer);
 549
 550 /** Like tvb_get_nstringz(), but never returns -1. The string is guaranteed to
 551  * have a terminating NUL. If the string was truncated when copied into buffer,
 552  * a NUL is placed at the end of buffer to terminate it.
 553  *
 554  * bufsize MUST be greater than 0.
 555  */
 556 WS_DLL_PUBLIC gint tvb_get_nstringz0(tvbuff_t *tvb, const gint offset,
 557     const guint bufsize, guint8 *buffer);
 558
 559 /**
 560  * Given a tvbuff, an offset into the tvbuff, and a length that starts
 561  * at that offset (which may be -1 for "all the way to the end of the
 562  * tvbuff"), find the end of the (putative) line that starts at the
 563  * specified offset in the tvbuff, going no further than the specified
 564  * length.
 565  *
 566  * Return the length of the line (not counting the line terminator at
 567  * the end), or, if we don't find a line terminator:
 568  *
 569  *  if "deseg" is true, return -1;
 570  *
 571  *  if "deseg" is false, return the amount of data remaining in
 572  *  the buffer.
 573  *
 574  * Set "*next_offset" to the offset of the character past the line
 575  * terminator, or past the end of the buffer if we don't find a line
 576  * terminator.  (It's not set if we return -1.)
 577  */
 578 WS_DLL_PUBLIC gint tvb_find_line_end(tvbuff_t *tvb, const gint offset, int len,
 579     gint *next_offset, const gboolean desegment);
 580
 581 /**
 582  * Given a tvbuff, an offset into the tvbuff, and a length that starts
 583  * at that offset (which may be -1 for "all the way to the end of the
 584  * tvbuff"), find the end of the (putative) line that starts at the
 585  * specified offset in the tvbuff, going no further than the specified
 586  * length.
 587  *
 588  * However, treat quoted strings inside the buffer specially - don't
 589  * treat newlines in quoted strings as line terminators.
 590  *
 591  * Return the length of the line (not counting the line terminator at
 592  * the end), or the amount of data remaining in the buffer if we don't
 593  * find a line terminator.
 594  *
 595  * Set "*next_offset" to the offset of the character past the line
 596  * terminator, or past the end of the buffer if we don't find a line
 597  * terminator.
 598  */
 599 WS_DLL_PUBLIC gint tvb_find_line_end_unquoted(tvbuff_t *tvb, const gint offset,
 600     int len, gint *next_offset);
 601
 602 /**
 603  * Copied from the mgcp dissector. (This function should be moved to /epan )
 604  * tvb_skip_wsp - Returns the position in tvb of the first non-whitespace
 605  *                character following offset or offset + maxlength -1 whichever
 606  *                is smaller.
 607  *
 608  * Parameters:
 609  * tvb - The tvbuff in which we are skipping whitespace.
 610  * offset - The offset in tvb from which we begin trying to skip whitespace.
 611  * maxlength - The maximum distance from offset that we may try to skip
 612  * whitespace.
 613  *
 614  * Returns: The position in tvb of the first non-whitespace
 615  *          character following offset or offset + maxlength -1 whichever
 616  *          is smaller.
 617  */
 618
 619 WS_DLL_PUBLIC gint tvb_skip_wsp(tvbuff_t *tvb, const gint offset,
 620     const gint maxlength);
 621
 622 WS_DLL_PUBLIC gint tvb_skip_wsp_return(tvbuff_t *tvb, const gint offset);
 623
 624 /**
 625  * Call strncmp after checking if enough chars left, returning 0 if
 626  * it returns 0 (meaning "equal") and -1 otherwise, otherwise return -1.
 627  */
 628 WS_DLL_PUBLIC gint tvb_strneql(tvbuff_t *tvb, const gint offset,
 629     const gchar *str, const size_t size);
 630
 631 /**
 632  * Call g_ascii_strncasecmp after checking if enough chars left, returning
 633  * 0 if it returns 0 (meaning "equal") and -1 otherwise, otherwise return -1.
 634  */
 635 WS_DLL_PUBLIC gint tvb_strncaseeql(tvbuff_t *tvb, const gint offset,
 636     const gchar *str, const size_t size);
 637
 638 /**
 639  * Call memcmp after checking if enough chars left, returning 0 if
 640  * it returns 0 (meaning "equal") and -1 otherwise, otherwise return -1.
 641  */
 642 WS_DLL_PUBLIC gint tvb_memeql(tvbuff_t *tvb, const gint offset,
 643     const guint8 *str, size_t size);
 644
 645 /**
 646  * Format a bunch of data from a tvbuff as bytes, returning a pointer
 647  * to the string with the formatted data, with "punct" as a byte
 648  * separator.
 649  */
 650 WS_DLL_PUBLIC gchar *tvb_bytes_to_str_punct(tvbuff_t *tvb, const gint offset,
 651     const gint len, const gchar punct);
 652
 653 /**
 654  * Format a bunch of data from a tvbuff as bytes, returning a pointer
 655  * to the string with the formatted data.
 656  */
 657 WS_DLL_PUBLIC gchar *tvb_bytes_to_str(tvbuff_t *tvb, const gint offset,
 658     const gint len);
 659
 660 /**
 661  * Given a tvbuff, an offset into the tvbuff, and a length that starts
 662  * at that offset (which may be -1 for "all the way to the end of the
 663  * tvbuff"), fetch BCD encoded digits from a tvbuff starting from either
 664  * the low or high half byte, formatting the digits according to an input digit
 665  * set, if NUL a default digit set of 0-9 returning "?" for overdecadic digits
 666  * will be used.  A pointer to the EP allocated string will be returned.
 667  * Note a tvbuff content of 0xf is considered a 'filler' and will end the
 668  * conversion.
 669  */
 670 typedef struct dgt_set_t
 671 {
 672     const unsigned char out[15];
 673 }
 674 dgt_set_t;
 675
 676 WS_DLL_PUBLIC const gchar *tvb_bcd_dig_to_wmem_packet_str(tvbuff_t *tvb,
 677     const gint offset, const gint len, dgt_set_t *dgt, gboolean skip_first);
 678
 679 /** Locate a sub-tvbuff within another tvbuff, starting at position
 680  * 'haystack_offset'. Returns the index of the beginning of 'needle' within
 681  * 'haystack', or -1 if 'needle' is not found. The index is relative
 682  * to the start of 'haystack', not 'haystack_offset'. */
 683 WS_DLL_PUBLIC gint tvb_find_tvb(tvbuff_t *haystack_tvb, tvbuff_t *needle_tvb,
 684     const gint haystack_offset);
 685
 686 /**
 687  * Uncompresses a zlib compressed packet inside a tvbuff at offset with
 688  * length comprlen.  Returns an uncompressed tvbuffer if uncompression
 689  * succeeded or NULL if uncompression failed.
 690  */
 691 WS_DLL_PUBLIC tvbuff_t *tvb_uncompress(tvbuff_t *tvb, const int offset,
 692     int comprlen);
 693
 694 /**
 695  * Uncompresses a zlib compressed packet inside a tvbuff at offset with
 696  * length comprlen.  Returns an uncompressed tvbuffer attached to tvb if
 697  * uncompression succeeded or NULL if uncompression failed.
 698  */
 699 extern tvbuff_t *tvb_child_uncompress(tvbuff_t *parent, tvbuff_t *tvb,
 700     const int offset, int comprlen);
 701
 702 /************** END OF ACCESSORS ****************/
 703
 704 /** @} */
 705
 706 #ifdef __cplusplus
 707 }
 708 #endif /* __cplusplus */
 709
 710 #endif /* __TVBUFF_H__ */
 711
 712 /*
 713  * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
 714  *
 715  * Local variables:
 716  * c-basic-offset: 4
 717  * tab-width: 4
 718  * indent-tabs-mode: nil
 719  * End:
 720  *
 721  * vi: set shiftwidth=4 tabstop=4 expandtab:
 722  * :indentSize=4:tabSize=4:noTabs=true:
 723  */
 724