3 * Testy, Virtual(-izable) Buffer of guint8*'s
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.
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
14 * Copyright (c) 2000 by Gilbert Ramirez <gram@alumni.rice.edu>
16 * Wireshark - Network traffic analyzer
17 * By Gerald Combs <gerald@wireshark.org>
18 * Copyright 1998 Gerald Combs
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.
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.
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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
39 #include <epan/ipv6-utils.h>
40 #include <epan/guid-utils.h>
41 #include "exceptions.h"
45 #endif /* __cplusplus */
48 * "testy, virtual(-izable) buffer". They are testy in that they get mad when
49 * an attempt is made to access data beyond the bounds of their array. In that
50 * case, they throw an exception.
52 * They are virtualizable in that new tvbuff's can be made from other tvbuffs,
53 * while only the original tvbuff may have data. That is, the new tvbuff has
57 /** The different types of tvbuff's */
65 typedef struct tvbuff tvbuff_t;
68 * tvbuffs: dissector use and management
70 * Consider a collection of tvbs as being a chain or stack of tvbs.
72 * The top-level dissector (packet.c) pushes the initial tvb onto the stack
73 * (starts the chain) and then calls a sub-dissector which in turn calls the next
74 * sub-dissector and so on. Each sub-dissector may chain additional tvbs to
75 * the tvb handed to that dissector. After dissection is complete and control has
76 * returned to the top-level dissector, the chain of tvbs (stack) is free'd
77 * via a call to tvb_free_chain() (in epan_dissect_cleanup()).
80 * - Can chain new tvbs (real, subset, composite) to the tvb
81 * handed to the dissector via tvb_subset(), tvb_new_child_real_data(), etc.
82 * (Subset and Composite tvbs should reference only tvbs which are
83 * already part of the chain).
84 * - Must not save a pointer to a tvb handed to the dissector for
85 * use when dissecting another frame; A higher level function
86 * may very well free the chain). This also applies to any tvbs chained
87 * by the dissector to the tvb handed to the dissector.
88 * - Can create its own tvb chain (using tvb_new_real_data() which
89 * the dissector is free to manage as desired. */
91 /** TVBUFF_REAL_DATA contains a guint8* that points to real data.
92 * The data is allocated and contiguous.
94 * TVBUFF_SUBSET has a backing tvbuff. The TVBUFF_SUBSET is a "window"
95 * through which the program sees only a portion of the backing tvbuff.
97 * TVBUFF_COMPOSITE combines multiple tvbuffs sequentually to produce
98 * a larger byte array.
100 * tvbuff's of any type can be used as the backing-tvbuff of a
101 * TVBUFF_SUBSET or as the member of a TVBUFF_COMPOSITE.
102 * TVBUFF_COMPOSITEs can have member-tvbuffs of different types.
104 * Once a tvbuff is create/initialized/finalized, the tvbuff is read-only.
105 * That is, it cannot point to any other data. A new tvbuff must be created if
106 * you want a tvbuff that points to other data.
108 * tvbuff's are normally chained together to allow efficient de-allocation of tvbuff's.
112 typedef void (*tvbuff_free_cb_t)(void*);
114 /** Returns a pointer to a newly initialized tvbuff. Note that
115 * tvbuff's of types TVBUFF_SUBSET and TVBUFF_COMPOSITE
116 * require further initialization via the appropriate functions. */
117 extern tvbuff_t* tvb_new(tvbuff_type);
119 /** Extracts 'number of bits' starting at 'bit offset'.
120 * Returns a pointer to a newly initialized ep_alloc'd REAL_DATA
121 * tvbuff with the bits octet aligned.
123 extern tvbuff_t* tvb_new_octet_aligned(tvbuff_t *tvb, guint32 bit_offset, gint32 no_of_bits);
125 /** Free a tvbuff_t and all tvbuffs chained from it
126 * The tvbuff must be 'the 'head' (initial) tvb of a chain or
127 * must not be in a chain.
128 * If specified, a callback to free the tvbuff data will be invoked
129 * for each tvbuff free'd */
130 extern void tvb_free(tvbuff_t*);
132 /** Free the tvbuff_t and all tvbuffs chained from it.
133 * The tvbuff must be 'the 'head' (initial) tvb of a chain or
134 * must not be in a chain.
135 * If specified, a callback to free the tvbuff data will be invoked
136 * for each tvbuff free'd */
137 extern void tvb_free_chain(tvbuff_t*);
139 /** Set a callback function to call when a tvbuff is actually freed
140 * One argument is passed to that callback --- a void* that points
141 * to the real data. Obviously, this only applies to a
142 * TVBUFF_REAL_DATA tvbuff. */
143 extern void tvb_set_free_cb(tvbuff_t*, const tvbuff_free_cb_t);
145 /** Attach a TVBUFF_REAL_DATA tvbuff to a parent tvbuff. This connection
146 * is used during a tvb_free_chain()... the "child" TVBUFF_REAL_DATA acts
147 * as if is part of the chain-of-creation of the parent tvbuff, although it
148 * isn't. This is useful if you need to take the data from some tvbuff,
149 * run some operation on it, like decryption or decompression, and make a new
150 * tvbuff from it, yet want the new tvbuff to be part of the chain. The reality
151 * is that the new tvbuff *is* part of the "chain of creation", but in a way
152 * that these tvbuff routines are ignorant of. Use this function to make
153 * the tvbuff routines knowledgable of this fact. */
154 extern void tvb_set_child_real_data_tvbuff(tvbuff_t* parent, tvbuff_t* child);
156 extern tvbuff_t* tvb_new_child_real_data(tvbuff_t* parent, const guint8* data, const guint length,
157 const gint reported_length);
159 /** Sets parameters for TVBUFF_REAL_DATA. Can throw ReportedBoundsError. */
160 extern void tvb_set_real_data(tvbuff_t*, const guint8* data, const guint length,
161 const gint reported_length);
163 /** Combination of tvb_new() and tvb_set_real_data(). Can throw ReportedBoundsError.
164 * Normally, a callback to free the data should be registered using tvb_set_free_cb();
165 * when this tvbuff is freed, then your callback will be called, and at that time
166 * you can free your original data. */
167 extern tvbuff_t* tvb_new_real_data(const guint8* data, const guint length,
168 const gint reported_length);
170 /** Define the subset of the backing buffer to use.
172 * 'backing_offset' can be negative, to indicate bytes from
173 * the end of the backing buffer.
175 * 'backing_length' can be 0, although the usefulness of the buffer would
178 * 'backing_length' of -1 means "to the end of the backing buffer"
180 * Will throw BoundsError if 'backing_offset'/'length'
181 * is beyond the bounds of the backing tvbuff.
182 * Can throw ReportedBoundsError. */
183 extern void tvb_set_subset(tvbuff_t* tvb, tvbuff_t* backing,
184 const gint backing_offset, const gint backing_length, const gint reported_length);
186 /** Combination of tvb_new() and tvb_set_subset()
187 * Can throw ReportedBoundsError. */
188 extern tvbuff_t* tvb_new_subset(tvbuff_t* backing,
189 const gint backing_offset, const gint backing_length, const gint reported_length);
191 /** Similar to tvb_new_subset() but with backing_length and reported_length set to -1.
192 * Can throw ReportedBoundsError. */
193 extern tvbuff_t* tvb_new_subset_remaining(tvbuff_t* backing,
194 const gint backing_offset);
196 /** Both tvb_composite_append and tvb_composite_prepend can throw
197 * BoundsError if member_offset/member_length goes beyond bounds of
198 * the 'member' tvbuff. */
200 /** Append to the list of tvbuffs that make up this composite tvbuff */
201 extern void tvb_composite_append(tvbuff_t* tvb, tvbuff_t* member);
203 /** Prepend to the list of tvbuffs that make up this composite tvbuff */
204 extern void tvb_composite_prepend(tvbuff_t* tvb, tvbuff_t* member);
206 /** Helper function that calls tvb_new(TVBUFF_COMPOSITE).
207 * Provided only to maintain symmetry with other constructors */
208 extern tvbuff_t* tvb_new_composite(void);
210 /** Mark a composite tvbuff as initialized. No further appends or prepends
211 * occur, data access can finally happen after this finalization. */
212 extern void tvb_composite_finalize(tvbuff_t* tvb);
215 /* Get total length of buffer */
216 extern guint tvb_length(const tvbuff_t*);
218 /** Computes bytes to end of buffer, from offset (which can be negative,
219 * to indicate bytes from end of buffer). Function returns -1 to
220 * indicate that offset is out of bounds. No exception is thrown. */
221 extern gint tvb_length_remaining(const tvbuff_t*, const gint offset);
223 /** Same as above, but throws an exception if the offset is out of bounds. */
224 extern guint tvb_ensure_length_remaining(const tvbuff_t*, const gint offset);
226 /* Checks (w/o throwing exception) that the bytes referred to by
227 * 'offset'/'length' actually exist in the buffer */
228 extern gboolean tvb_bytes_exist(const tvbuff_t*, const gint offset, const gint length);
230 /** Checks that the bytes referred to by 'offset'/'length' actually exist
231 * in the buffer, and throws an exception if they aren't. */
232 extern void tvb_ensure_bytes_exist(const tvbuff_t *tvb, const gint offset, const gint length);
234 /* Checks (w/o throwing exception) that offset exists in buffer */
235 extern gboolean tvb_offset_exists(const tvbuff_t*, const gint offset);
237 /* Get reported length of buffer */
238 extern guint tvb_reported_length(const tvbuff_t*);
240 /** Computes bytes of reported packet data to end of buffer, from offset
241 * (which can be negative, to indicate bytes from end of buffer). Function
242 * returns -1 to indicate that offset is out of bounds. No exception is
244 extern gint tvb_reported_length_remaining(const tvbuff_t *tvb, const gint offset);
246 /** Set the reported length of a tvbuff to a given value; used for protocols
247 whose headers contain an explicit length and where the calling
248 dissector's payload may include padding as well as the packet for
251 Also adjusts the data length. */
252 extern void tvb_set_reported_length(tvbuff_t*, const guint);
254 extern guint tvb_offset_from_real_beginning(const tvbuff_t *tvb);
256 /* Returns the offset from the first byte of real data. */
257 extern gint tvb_raw_offset(tvbuff_t *tvb);
259 /************** START OF ACCESSORS ****************/
260 /* All accessors will throw an exception if appropriate */
262 extern guint8 tvb_get_guint8(tvbuff_t*, const gint offset);
264 extern guint16 tvb_get_ntohs(tvbuff_t*, const gint offset);
265 extern guint32 tvb_get_ntoh24(tvbuff_t*, const gint offset);
266 extern guint32 tvb_get_ntohl(tvbuff_t*, const gint offset);
267 extern guint64 tvb_get_ntoh40(tvbuff_t*, const gint offset);
268 extern guint64 tvb_get_ntoh48(tvbuff_t*, const gint offset);
269 extern guint64 tvb_get_ntoh56(tvbuff_t*, const gint offset);
270 extern guint64 tvb_get_ntoh64(tvbuff_t*, const gint offset);
271 extern gfloat tvb_get_ntohieee_float(tvbuff_t*, const gint offset);
272 extern gdouble tvb_get_ntohieee_double(tvbuff_t*, const gint offset);
274 extern guint16 tvb_get_letohs(tvbuff_t*, const gint offset);
275 extern guint32 tvb_get_letoh24(tvbuff_t*, const gint offset);
276 extern guint32 tvb_get_letohl(tvbuff_t*, const gint offset);
277 extern guint64 tvb_get_letoh40(tvbuff_t*, const gint offset);
278 extern guint64 tvb_get_letoh48(tvbuff_t*, const gint offset);
279 extern guint64 tvb_get_letoh56(tvbuff_t*, const gint offset);
280 extern guint64 tvb_get_letoh64(tvbuff_t*, const gint offset);
281 extern gfloat tvb_get_letohieee_float(tvbuff_t*, const gint offset);
282 extern gdouble tvb_get_letohieee_double(tvbuff_t*, const gint offset);
285 * Fetch an IPv4 address, in network byte order.
286 * We do *not* convert it to host byte order; we leave it in
287 * network byte order, as that's what its callers expect. */
288 extern guint32 tvb_get_ipv4(tvbuff_t*, const gint offset);
290 /* Fetch an IPv6 address. */
291 extern void tvb_get_ipv6(tvbuff_t*, const gint offset, struct e_in6_addr *addr);
294 extern void tvb_get_ntohguid(tvbuff_t *tvb, const gint offset, e_guid_t *guid);
295 extern void tvb_get_letohguid(tvbuff_t *tvb, const gint offset, e_guid_t *guid);
296 extern void tvb_get_guid(tvbuff_t *tvb, const gint offset, e_guid_t *guid, const guint representation);
298 /* Fetch a specified number of bits from bit offset in a tvb.
299 All of these functions are equivalent, except for the type of the retun value.
300 Note that the parameter encoding (where supplied) is meaningless and ignored */
302 /* get 1 - 8 bits returned in a guint8 */
303 extern guint8 tvb_get_bits8(tvbuff_t *tvb, gint bit_offset, const gint no_of_bits);
304 /* get 1 - 16 bits returned in a guint16 */
305 extern guint16 tvb_get_bits16(tvbuff_t *tvb, gint bit_offset, const gint no_of_bits, const guint encoding);
306 /* get 1 - 32 bits returned in a guint32 */
307 extern guint32 tvb_get_bits32(tvbuff_t *tvb, gint bit_offset, const gint no_of_bits, const guint encoding);
308 /* get 1 - 64 bits returned in a guint64 */
309 extern guint64 tvb_get_bits64(tvbuff_t *tvb, gint bit_offset, const gint no_of_bits, const guint encoding);
312 * This function has EXACTLY the same behaviour as
315 extern guint32 tvb_get_bits(tvbuff_t *tvb, const gint bit_offset, const gint no_of_bits, const guint encoding);
317 void tvb_get_bits_buf(tvbuff_t *tvb, gint bit_offset, gint no_of_bits, guint8 *buf, gboolean lsb0);
318 guint8 *ep_tvb_get_bits(tvbuff_t *tvb, gint bit_offset, gint no_of_bits, gboolean lsb0);
320 /** Returns target for convenience. Does not suffer from possible
321 * expense of tvb_get_ptr(), since this routine is smart enough
322 * to copy data in chunks if the request range actually exists in
323 * different TVBUFF_REAL_DATA tvbuffs. This function assumes that the
324 * target memory is already allocated; it does not allocate or free the
326 extern void* tvb_memcpy(tvbuff_t*, void* target, const gint offset, size_t length);
328 /** It is the user's responsibility to g_free() the memory allocated by
329 * tvb_memdup(). Calls tvb_memcpy() */
330 extern void* tvb_memdup(tvbuff_t*, const gint offset, size_t length);
332 /* Same as above but the buffer returned from this function does not have to
333 * be freed. It will be automatically freed after the packet is dissected.
334 * Buffers allocated by this function are NOT persistent.
336 extern void* ep_tvb_memdup(tvbuff_t *tvb, const gint offset, size_t length);
338 /** WARNING! This function is possibly expensive, temporarily allocating
339 * another copy of the packet data. Furthermore, it's dangerous because once
340 * this pointer is given to the user, there's no guarantee that the user will
341 * honor the 'length' and not overstep the boundaries of the buffer.
343 * If you're thinking of using tvb_get_ptr, STOP WHAT YOU ARE DOING
344 * IMMEDIATELY. Go take a break. Consider that tvb_get_ptr hands you
345 * a raw, unprotected pointer that you can easily use to create a
346 * security vulnerability or otherwise crash Wireshark. Then consider
347 * that you can probably find a function elsewhere in this file that
348 * does exactly what you want in a much more safe and robust manner.
350 * The returned pointer is data that is internal to the tvbuff, so do not
351 * attempt to free it. Don't modify the data, either, because another tvbuff
352 * that might be using this tvbuff may have already copied that portion of
353 * the data (sometimes tvbuff's need to make copies of data, but that's the
354 * internal implementation that you need not worry about). Assume that the
355 * guint8* points to read-only data that the tvbuff manages.
357 * Return a pointer into our buffer if the data asked for via 'offset'/'length'
358 * is contiguous (which might not be the case for TVBUFF_COMPOSITE). If the
359 * data is not contiguous, a tvb_memdup() is called for the entire buffer
360 * and the pointer to the newly-contiguous data is returned. This dynamically-
361 * allocated memory will be freed when the tvbuff is freed, after the
362 * tvbuff_free_cb_t() is called, if any. */
363 extern const guint8* tvb_get_ptr(tvbuff_t*, const gint offset, const gint length);
365 /** Find first occurence of any of the needles in tvbuff, starting at offset.
366 * Searches at most maxlength number of bytes; if maxlength is -1, searches
368 * Returns the offset of the found needle, or -1 if not found.
369 * Will not throw an exception, even if maxlength exceeds boundary of tvbuff;
370 * in that case, -1 will be returned if the boundary is reached before
372 extern gint tvb_find_guint8(tvbuff_t*, const gint offset, const gint maxlength,
373 const guint8 needle);
375 /** Find first occurence of any of the needles in tvbuff, starting at offset.
376 * Searches at most maxlength number of bytes. Returns the offset of the
377 * found needle, or -1 if not found and the found needle.
378 * Will not throw an exception, even if
379 * maxlength exceeds boundary of tvbuff; in that case, -1 will be returned if
380 * the boundary is reached before finding needle. */
381 extern gint tvb_pbrk_guint8(tvbuff_t *, const gint offset, const gint maxlength,
382 const guint8 *needles, guchar *found_needle);
384 /** Find size of stringz (NUL-terminated string) by looking for terminating
385 * NUL. The size of the string includes the terminating NUL.
387 * If the NUL isn't found, it throws the appropriate exception.
389 extern guint tvb_strsize(tvbuff_t *tvb, const gint offset);
391 /** Find length of string by looking for end of zero terminated string, up to
392 * 'maxlength' characters'; if 'maxlength' is -1, searches to end
394 * Returns -1 if 'maxlength' reached before finding EOS. */
395 extern gint tvb_strnlen(tvbuff_t*, const gint offset, const guint maxlength);
397 /** Convert a string from Unicode to ASCII. At the moment we fake it by
398 * assuming all characters are ASCII )-: The len parameter is the number
399 * of guint16's to convert from Unicode.
401 * XXX - These functions have been superceded by tvb_get_unicode_string()
402 * and tvb_get_ephemeral_unicode_string()
404 * tvb_fake_unicode() returns a buffer allocated by g_malloc() and must
405 * be g_free() by the caller.
406 * tvb_get_ephemeral_faked_unicode() returns a buffer that does not need
407 * to be explicitely freed. Instead this buffer is
408 * automatically freed when wireshark starts dissecting
411 extern char *tvb_fake_unicode(tvbuff_t *tvb, int offset, const int len,
412 const gboolean little_endian);
413 extern char *tvb_get_ephemeral_faked_unicode(tvbuff_t *tvb, int offset, const int len,
414 const gboolean little_endian);
417 * Format the data in the tvb from offset for size ...
419 extern gchar * tvb_format_text(tvbuff_t *tvb, const gint offset, const gint size);
422 * Like "tvb_format_text()", but for 'wsp'; don't show
423 * the characters as C-style escapes.
425 extern gchar * tvb_format_text_wsp(tvbuff_t *tvb, const gint offset, const gint size);
428 * Like "tvb_format_text()", but for null-padded strings; don't show
429 * the null padding characters as "\000".
431 extern gchar *tvb_format_stringzpad(tvbuff_t *tvb, const gint offset, const gint size);
434 * Like "tvb_format_text_wsp()", but for null-padded strings; don't show
435 * the null padding characters as "\000".
437 extern gchar *tvb_format_stringzpad_wsp(tvbuff_t *tvb, const gint offset, const gint size);
441 * Given a tvbuff, an offset, and a length, allocate a buffer big enough
442 * to hold a non-null-terminated string of that length at that offset,
443 * plus a trailing zero, copy the string into it, and return a pointer
446 * Throws an exception if the tvbuff ends before the string does.
448 * tvb_get_string() returns a string allocated by g_malloc() and therefore
449 * MUST be g_free() by the caller in order not to leak
452 * tvb_get_unicode_string() Unicode (UTF-16) version of above
454 * tvb_get_ephemeral_string() returns a string that does not need to be freed,
455 * instead it will automatically be freed once the next
456 * packet is dissected.
458 * tvb_get_ephemeral_string_enc() takes a string encoding as well, and
459 * converts to UTF-8 from the encoding (only UTF-8 and
462 * tvb_get_ephemeral_unicode_string() Unicode (UTF-16) version of above
464 * tvb_get_seasonal_string() returns a string that does not need to be freed,
465 * instead it will automatically be freed when a new capture
468 extern guint8 *tvb_get_string(tvbuff_t *tvb, const gint offset, const gint length);
469 extern gchar *tvb_get_unicode_string(tvbuff_t *tvb, const gint offset, gint length, const guint encoding);
470 extern guint8 *tvb_get_ephemeral_string(tvbuff_t *tvb, const gint offset, const gint length);
471 extern guint8 *tvb_get_ephemeral_string_enc(tvbuff_t *tvb, const gint offset,
472 const gint length, const gint encoding);
473 extern gchar *tvb_get_ephemeral_unicode_string(tvbuff_t *tvb, const gint offset, gint length, const guint encoding);
474 extern guint8 *tvb_get_seasonal_string(tvbuff_t *tvb, const gint offset, const gint length);
478 * Given a tvbuff and an offset, with the offset assumed to refer to
479 * a null-terminated string, find the length of that string (and throw
480 * an exception if the tvbuff ends before we find the null), allocate
481 * a buffer big enough to hold the string, copy the string into it,
482 * and return a pointer to the string. Also return the length of the
483 * string (including the terminating null) through a pointer.
485 * tvb_get_stringz() returns a string allocated by g_malloc() and therefore
486 * MUST be g_free() by the caller in order not to leak
489 * tvb_get_stringz_enc() takes a string encoding as well, and converts to
490 * UTF-8 from the encoding (only UTF-8 and EBCDIC supported)
492 * tvb_get_const_stringz() returns a constant (unmodifiable) string that does
493 * not need to be freed, instead it will automatically be
494 * freed once the next packet is dissected. It is slightly
495 * more efficient than the other routines.
497 * tvb_get_ephemeral_stringz() returns a string that does not need to be freed,
498 * instead it will automatically be freed once the next
499 * packet is dissected.
501 * tvb_get_ephemeral_stringz_enc() takes a string encoding as well, and
502 * converts to UTF-8 from the encoding (only UTF-8 and
504 * packet is dissected.
506 * tvb_get_ephemeral_unicode_stringz() Unicode (UTF-16) version of above
508 * tvb_get_seasonal_stringz() returns a string that does not need to be freed,
509 * instead it will automatically be freed when a new capture
512 extern guint8 *tvb_get_stringz(tvbuff_t *tvb, const gint offset, gint *lengthp);
513 extern guint8 *tvb_get_stringz_enc(tvbuff_t *tvb, const gint offset, gint *lengthp, gint encoding);
514 extern const guint8 *tvb_get_const_stringz(tvbuff_t *tvb, const gint offset, gint *lengthp);
515 extern guint8 *tvb_get_ephemeral_stringz(tvbuff_t *tvb, const gint offset, gint *lengthp);
516 extern guint8 *tvb_get_ephemeral_stringz_enc(tvbuff_t *tvb, const gint offset, gint *lengthp, gint encoding);
517 extern gchar *tvb_get_ephemeral_unicode_stringz(tvbuff_t *tvb, const gint offset, gint *lengthp, const guint encoding);
518 extern guint8 *tvb_get_seasonal_stringz(tvbuff_t *tvb, const gint offset, gint *lengthp);
520 /** Looks for a stringz (NUL-terminated string) in tvbuff and copies
521 * no more than bufsize number of bytes, including terminating NUL, to buffer.
522 * Returns length of string (not including terminating NUL), or -1 if the string was
523 * truncated in the buffer due to not having reached the terminating NUL.
524 * In this way, it acts like g_snprintf().
526 * When processing a packet where the remaining number of bytes is less
527 * than bufsize, an exception is not thrown if the end of the packet
528 * is reached before the NUL is found. If no NUL is found before reaching
529 * the end of the short packet, -1 is still returned, and the string
530 * is truncated with a NUL, albeit not at buffer[bufsize - 1], but
531 * at the correct spot, terminating the string.
533 extern gint tvb_get_nstringz(tvbuff_t *tvb, const gint offset, const guint bufsize,
536 /** Like tvb_get_nstringz(), but never returns -1. The string is guaranteed to
537 * have a terminating NUL. If the string was truncated when copied into buffer,
538 * a NUL is placed at the end of buffer to terminate it.
540 * bufsize MUST be greater than 0.
542 extern gint tvb_get_nstringz0(tvbuff_t *tvb, const gint offset, const guint bufsize,
546 * Given a tvbuff, an offset into the tvbuff, and a length that starts
547 * at that offset (which may be -1 for "all the way to the end of the
548 * tvbuff"), find the end of the (putative) line that starts at the
549 * specified offset in the tvbuff, going no further than the specified
552 * Return the length of the line (not counting the line terminator at
553 * the end), or, if we don't find a line terminator:
555 * if "deseg" is true, return -1;
557 * if "deseg" is false, return the amount of data remaining in
560 * Set "*next_offset" to the offset of the character past the line
561 * terminator, or past the end of the buffer if we don't find a line
562 * terminator. (It's not set if we return -1.)
564 extern gint tvb_find_line_end(tvbuff_t *tvb, const gint offset, int len,
565 gint *next_offset, const gboolean desegment);
568 * Given a tvbuff, an offset into the tvbuff, and a length that starts
569 * at that offset (which may be -1 for "all the way to the end of the
570 * tvbuff"), find the end of the (putative) line that starts at the
571 * specified offset in the tvbuff, going no further than the specified
574 * However, treat quoted strings inside the buffer specially - don't
575 * treat newlines in quoted strings as line terminators.
577 * Return the length of the line (not counting the line terminator at
578 * the end), or the amount of data remaining in the buffer if we don't
579 * find a line terminator.
581 * Set "*next_offset" to the offset of the character past the line
582 * terminator, or past the end of the buffer if we don't find a line
585 extern gint tvb_find_line_end_unquoted(tvbuff_t *tvb, const gint offset, int len,
589 * Copied from the mgcp dissector. (This function should be moved to /epan )
590 * tvb_skip_wsp - Returns the position in tvb of the first non-whitespace
591 * character following offset or offset + maxlength -1 whichever
595 * tvb - The tvbuff in which we are skipping whitespace.
596 * offset - The offset in tvb from which we begin trying to skip whitespace.
597 * maxlength - The maximum distance from offset that we may try to skip
600 * Returns: The position in tvb of the first non-whitespace
601 * character following offset or offset + maxlength -1 whichever
605 extern gint tvb_skip_wsp(tvbuff_t* tvb, const gint offset, const gint maxlength);
607 extern gint tvb_skip_wsp_return(tvbuff_t* tvb, const gint offset);
610 * Call strncmp after checking if enough chars left, returning 0 if
611 * it returns 0 (meaning "equal") and -1 otherwise, otherwise return -1.
613 extern gint tvb_strneql(tvbuff_t *tvb, const gint offset, const gchar *str,
617 * Call g_ascii_strncasecmp after checking if enough chars left, returning
618 * 0 if it returns 0 (meaning "equal") and -1 otherwise, otherwise return -1.
620 extern gint tvb_strncaseeql(tvbuff_t *tvb, const gint offset, const gchar *str,
624 * Call memcmp after checking if enough chars left, returning 0 if
625 * it returns 0 (meaning "equal") and -1 otherwise, otherwise return -1.
627 extern gint tvb_memeql(tvbuff_t *tvb, const gint offset, const guint8 *str,
631 * Format a bunch of data from a tvbuff as bytes, returning a pointer
632 * to the string with the formatted data, with "punct" as a byte
635 extern gchar *tvb_bytes_to_str_punct(tvbuff_t *tvb, const gint offset, const gint len,
639 * Format a bunch of data from a tvbuff as bytes, returning a pointer
640 * to the string with the formatted data.
642 extern gchar *tvb_bytes_to_str(tvbuff_t *tvb, const gint offset, const gint len);
645 * Given a tvbuff, an offset into the tvbuff, and a length that starts
646 * at that offset (which may be -1 for "all the way to the end of the
647 * tvbuff"), fetch BCD encoded digits from a tvbuff starting from either
648 * the low or high half byte, formating the digits according to an input digit set,
649 * if NUll a default digit set of 0-9 returning "?" for overdecadic digits will be used.
650 * A pointer to the EP allocated string will be returned.
651 * Note a tvbuff content of 0xf is considered a 'filler' and will end the conversion.
653 typedef struct dgt_set_t
655 const unsigned char out[15];
659 extern const gchar *tvb_bcd_dig_to_ep_str(tvbuff_t *tvb, const gint offset, const gint len, dgt_set_t *dgt, gboolean skip_first);
661 struct tvbuff *tvb_get_ds_tvb(tvbuff_t *tvb);
663 /** Locate a sub-tvbuff within another tvbuff, starting at position
664 * 'haystack_offset'. Returns the index of the beginning of 'needle' within
665 * 'haystack', or -1 if 'needle' is not found. The index is relative
666 * to the start of 'haystack', not 'haystack_offset'. */
667 extern gint tvb_find_tvb(tvbuff_t *haystack_tvb, tvbuff_t *needle_tvb,
668 const gint haystack_offset);
671 * Uncompresses a zlib compressed packet inside a tvbuff at offset with
672 * length comprlen. Returns an uncompressed tvbuffer if uncompression
673 * succeeded or NULL if uncompression failed.
675 extern tvbuff_t* tvb_uncompress(tvbuff_t *tvb, const int offset, int comprlen);
678 * Uncompresses a zlib compressed packet inside a tvbuff at offset with
679 * length comprlen. Returns an uncompressed tvbuffer attached to tvb if uncompression
680 * succeeded or NULL if uncompression failed.
682 extern tvbuff_t* tvb_child_uncompress(tvbuff_t *parent, tvbuff_t *tvb, const int offset, int comprlen);
684 /************** END OF ACCESSORS ****************/
688 #endif /* __cplusplus */
690 #endif /* __TVBUFF_H__ */