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 * Ethereal - Network traffic analyzer
17 * By Gerald Combs <gerald@ethereal.com>
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 "exceptions.h"
42 * "testy, virtual(-izable) buffer". They are testy in that they get mad when
43 * an attempt is made to access data beyond the bounds of their array. In that
44 * case, they throw an exception.
46 * They are virtualizable in that new tvbuff's can be made from other tvbuffs,
47 * while only the original tvbuff may have data. That is, the new tvbuff has
52 /** The different types of tvbuff's */
60 /* The backing tvbuff_t */
63 /* The offset/length of 'tvb' to which I'm privy */
72 /* Used for quick testing to see if this
73 * is the tvbuff that a COMPOSITE is
80 typedef void (*tvbuff_free_cb_t)(void*);
82 typedef struct tvbuff {
87 struct tvbuff *ds_tvb; /* data source top-level tvbuff */
89 /* The tvbuffs in which this tvbuff is a member
90 * (that is, a backing tvbuff for a TVBUFF_SUBSET
91 * or a member for a TVB_COMPOSITE) */
94 /* TVBUFF_SUBSET and TVBUFF_COMPOSITE keep track
95 * of the other tvbuff's they use */
101 /* We're either a TVBUFF_REAL_DATA or a
102 * TVBUFF_SUBSET that has a backing buffer that
103 * has real_data != NULL, or a TVBUFF_COMPOSITE
104 * which has flattened its data due to a call
107 const guint8 *real_data;
109 /* Length of virtual buffer (and/or real_data). */
112 /* Reported length. */
113 guint reported_length;
115 /* Offset from beginning of first TVBUFF_REAL. */
118 /* Func to call when actually freed */
119 tvbuff_free_cb_t free_cb;
124 /** TVBUFF_REAL_DATA contains a guint8* that points to real data.
125 * The data is allocated and contiguous.
127 * TVBUFF_SUBSET has a backing tvbuff. The TVBUFF_SUBSET is a "window"
128 * through which the program sees only a portion of the backing tvbuff.
130 * TVBUFF_COMPOSITE combines multiple tvbuffs sequentually to produce
131 * a larger byte array.
133 * tvbuff's of any type can be used as the backing-tvbuff of a
134 * TVBUFF_SUBSET or as the member of a TVBUFF_COMPOSITE.
135 * TVBUFF_COMPOSITEs can have member-tvbuffs of different types.
137 * Once a tvbuff is create/initialized/finalized, the tvbuff is read-only.
138 * That is, it cannot point to any other data. A new tvbuff must be created if
139 * you want a tvbuff that points to other data.
143 /** "class" initialization. Called once during execution of program
144 * so that tvbuff.c can initialize its data. */
145 extern void tvbuff_init(void);
147 /** "class" cleanup. Called once during execution of program
148 * so that tvbuff.c can clean up its data. */
149 extern void tvbuff_cleanup(void);
152 /** Returns a pointer to a newly initialized tvbuff. Note that
153 * tvbuff's of types TVBUFF_SUBSET and TVBUFF_COMPOSITE
154 * require further initialization via the appropriate functions */
155 extern tvbuff_t* tvb_new(tvbuff_type);
157 /** Marks a tvbuff for freeing. The guint8* data of a TVBUFF_REAL_DATA
158 * is *never* freed by the tvbuff routines. The tvbuff itself is actually freed
159 * once its usage count drops to 0.
161 * Usage counts increment for any time the tvbuff is
162 * used as a member of another tvbuff, i.e., as the backing buffer for
163 * a TVBUFF_SUBSET or as a member of a TVBUFF_COMPOSITE.
165 * Although you may call tvb_free(), the tvbuff may still be in use
166 * by other tvbuff's (TVBUFF_SUBSET or TVBUFF_COMPOSITE), so it is not
167 * safe, unless you know otherwise, to free your guint8* data. If you
168 * cannot be sure that your TVBUFF_REAL_DATA is not in use by another
169 * tvbuff, register a callback with tvb_set_free_cb(); when your tvbuff
170 * is _really_ freed, then your callback will be called, and at that time
171 * you can free your original data.
173 * The caller can artificially increment/decrement the usage count
174 * with tvbuff_increment_usage_count()/tvbuff_decrement_usage_count().
176 extern void tvb_free(tvbuff_t*);
178 /** Free the tvbuff_t and all tvbuff's created from it. */
179 extern void tvb_free_chain(tvbuff_t*);
181 /** Both return the new usage count, after the increment or decrement */
182 extern guint tvb_increment_usage_count(tvbuff_t*, guint count);
184 /** If a decrement causes the usage count to drop to 0, a the tvbuff
185 * is immediately freed. Be sure you know exactly what you're doing
186 * if you decide to use this function, as another tvbuff could
187 * still have a pointer to the just-freed tvbuff, causing corrupted data
188 * or a segfault in the future */
189 extern guint tvb_decrement_usage_count(tvbuff_t*, guint count);
191 /** Set a callback function to call when a tvbuff is actually freed
192 * (once the usage count drops to 0). One argument is passed to
193 * that callback --- a void* that points to the real data.
194 * Obviously, this only applies to a TVBUFF_REAL_DATA tvbuff. */
195 extern void tvb_set_free_cb(tvbuff_t*, tvbuff_free_cb_t);
198 /** Attach a TVBUFF_REAL_DATA tvbuff to a parent tvbuff. This connection
199 * is used during a tvb_free_chain()... the "child" TVBUFF_REAL_DATA acts
200 * as if is part of the chain-of-creation of the parent tvbuff, although it
201 * isn't. This is useful if you need to take the data from some tvbuff,
202 * run some operation on it, like decryption or decompression, and make a new
203 * tvbuff from it, yet want the new tvbuff to be part of the chain. The reality
204 * is that the new tvbuff *is* part of the "chain of creation", but in a way
205 * that these tvbuff routines is ignorant of. Use this function to make
206 * the tvbuff routines knowledgable of this fact. */
207 extern void tvb_set_child_real_data_tvbuff(tvbuff_t* parent, tvbuff_t* child);
209 /**Sets parameters for TVBUFF_REAL_DATA. Can throw ReportedBoundsError. */
210 extern void tvb_set_real_data(tvbuff_t*, const guint8* data, guint length,
211 gint reported_length);
213 /** Combination of tvb_new() and tvb_set_real_data(). Can throw ReportedBoundsError. */
214 extern tvbuff_t* tvb_new_real_data(const guint8* data, guint length,
215 gint reported_length);
218 /** Define the subset of the backing buffer to use.
220 * 'backing_offset' can be negative, to indicate bytes from
221 * the end of the backing buffer.
223 * 'backing_length' can be 0, although the usefulness of the buffer would
226 * 'backing_length' of -1 means "to the end of the backing buffer"
228 * Will throw BoundsError if 'backing_offset'/'length'
229 * is beyond the bounds of the backing tvbuff.
230 * Can throw ReportedBoundsError. */
231 extern void tvb_set_subset(tvbuff_t* tvb, tvbuff_t* backing,
232 gint backing_offset, gint backing_length, gint reported_length);
234 /** Combination of tvb_new() and tvb_set_subset()
235 * Can throw ReportedBoundsError. */
236 extern tvbuff_t* tvb_new_subset(tvbuff_t* backing,
237 gint backing_offset, gint backing_length, gint reported_length);
240 /** Both tvb_composite_append and tvb_composite_prepend can throw
241 * BoundsError if member_offset/member_length goes beyond bounds of
242 * the 'member' tvbuff. */
244 /** Append to the list of tvbuffs that make up this composite tvbuff */
245 extern void tvb_composite_append(tvbuff_t* tvb, tvbuff_t* member);
247 /** Prepend to the list of tvbuffs that make up this composite tvbuff */
248 extern void tvb_composite_prepend(tvbuff_t* tvb, tvbuff_t* member);
250 /** Helper function that calls tvb_new(TVBUFF_COMPOSITE).
251 * Provided only to maintain symmetry with other constructors */
252 extern tvbuff_t* tvb_new_composite(void);
254 /** Mark a composite tvbuff as initialized. No further appends or prepends
255 * occur, data access can finally happen after this finalization. */
256 extern void tvb_composite_finalize(tvbuff_t* tvb);
259 /* Get total length of buffer */
260 extern guint tvb_length(tvbuff_t*);
262 /** Computes bytes to end of buffer, from offset (which can be negative,
263 * to indicate bytes from end of buffer). Function returns -1 to
264 * indicate that offset is out of bounds. No exception is thrown. */
265 extern gint tvb_length_remaining(tvbuff_t*, gint offset);
267 /** Same as above, but throws an exception if the offset is out of bounds. */
268 extern guint tvb_ensure_length_remaining(tvbuff_t*, gint offset);
270 /* Checks (w/o throwing exception) that the bytes referred to by
271 * 'offset'/'length' actually exist in the buffer */
272 extern gboolean tvb_bytes_exist(tvbuff_t*, gint offset, gint length);
274 /** Checks that the bytes referred to by 'offset'/'length' actually exist
275 * in the buffer, and throws an exception if they aren't. */
276 extern void tvb_ensure_bytes_exist(tvbuff_t *tvb, gint offset, gint length);
278 /* Checks (w/o throwing exception) that offset exists in buffer */
279 extern gboolean tvb_offset_exists(tvbuff_t*, gint offset);
281 /* Get reported length of buffer */
282 extern guint tvb_reported_length(tvbuff_t*);
284 /** Computes bytes of reported packet data to end of buffer, from offset
285 * (which can be negative, to indicate bytes from end of buffer). Function
286 * returns -1 to indicate that offset is out of bounds. No exception is
288 extern gint tvb_reported_length_remaining(tvbuff_t *tvb, gint offset);
290 /** Set the reported length of a tvbuff to a given value; used for protocols
291 whose headers contain an explicit length and where the calling
292 dissector's payload may include padding as well as the packet for
295 Also adjusts the data length. */
296 extern void tvb_set_reported_length(tvbuff_t*, guint);
298 extern int offset_from_real_beginning(tvbuff_t *tvb, int counter);
300 /* Returns the offset from the first byte of real data. */
301 #define TVB_RAW_OFFSET(tvb) \
302 ((tvb->raw_offset==-1)?(tvb->raw_offset = offset_from_real_beginning(tvb, 0)):tvb->raw_offset)
304 /************** START OF ACCESSORS ****************/
305 /* All accessors will throw an exception if appropriate */
307 extern guint8 tvb_get_guint8(tvbuff_t*, gint offset);
309 extern guint16 tvb_get_ntohs(tvbuff_t*, gint offset);
310 extern guint32 tvb_get_ntoh24(tvbuff_t*, gint offset);
311 extern guint32 tvb_get_ntohl(tvbuff_t*, gint offset);
312 extern guint64 tvb_get_ntoh64(tvbuff_t*, gint offset);
313 extern gfloat tvb_get_ntohieee_float(tvbuff_t*, gint offset);
314 extern gdouble tvb_get_ntohieee_double(tvbuff_t*, gint offset);
316 extern guint16 tvb_get_letohs(tvbuff_t*, gint offset);
317 extern guint32 tvb_get_letoh24(tvbuff_t*, gint offset);
318 extern guint32 tvb_get_letohl(tvbuff_t*, gint offset);
319 extern guint64 tvb_get_letoh64(tvbuff_t*, gint offset);
320 extern gfloat tvb_get_letohieee_float(tvbuff_t*, gint offset);
321 extern gdouble tvb_get_letohieee_double(tvbuff_t*, gint offset);
323 /** Returns target for convenience. Does not suffer from possible
324 * expense of tvb_get_ptr(), since this routine is smart enough
325 * to copy data in chunks if the request range actually exists in
326 * different TVBUFF_REAL_DATA tvbuffs. This function assumes that the
327 * target memory is already allocated; it does not allocate or free the
329 extern guint8* tvb_memcpy(tvbuff_t*, guint8* target, gint offset, gint length);
331 /** It is the user's responsibility to g_free() the memory allocated by
332 * tvb_memdup(). Calls tvb_memcpy() */
333 extern guint8* tvb_memdup(tvbuff_t*, gint offset, gint length);
335 /** WARNING! This function is possibly expensive, temporarily allocating
336 * another copy of the packet data. Furthermore, it's dangerous because once
337 * this pointer is given to the user, there's no guarantee that the user will
338 * honor the 'length' and not overstep the boundaries of the buffer.
340 * The returned pointer is data that is internal to the tvbuff, so do not
341 * attempt to free it. Don't modify the data, either, because another tvbuff
342 * that might be using this tvbuff may have already copied that portion of
343 * the data (sometimes tvbuff's need to make copies of data, but that's the
344 * internal implementation that you need not worry about). Assume that the
345 * guint8* points to read-only data that the tvbuff manages.
347 * Return a pointer into our buffer if the data asked for via 'offset'/'length'
348 * is contiguous (which might not be the case for TVBUFF_COMPOSITE). If the
349 * data is not contiguous, a tvb_memdup() is called for the entire buffer
350 * and the pointer to the newly-contiguous data is returned. This dynamically-
351 * allocated memory will be freed when the tvbuff is freed, after the
352 * tvbuff_free_cb_t() is called, if any. */
353 extern const guint8* tvb_get_ptr(tvbuff_t*, gint offset, gint length);
355 /** Find first occurence of any of the needles in tvbuff, starting at offset.
356 * Searches at most maxlength number of bytes; if maxlength is -1, searches
358 * Returns the offset of the found needle, or -1 if not found.
359 * Will not throw an exception, even if maxlength exceeds boundary of tvbuff;
360 * in that case, -1 will be returned if the boundary is reached before
362 extern gint tvb_find_guint8(tvbuff_t*, gint offset, gint maxlength,
365 /** Find first occurence of any of the needles in tvbuff, starting at offset.
366 * Searches at most maxlength number of bytes. Returns the offset of the
367 * found needle, or -1 if not found. Will not throw an exception, even if
368 * maxlength exceeds boundary of tvbuff; in that case, -1 will be returned if
369 * the boundary is reached before finding needle. */
370 extern gint tvb_pbrk_guint8(tvbuff_t *, gint offset, gint maxlength,
373 /** Find size of stringz (NUL-terminated string) by looking for terminating
374 * NUL. The size of the string includes the terminating NUL.
376 * If the NUL isn't found, it throws the appropriate exception.
378 extern guint tvb_strsize(tvbuff_t *tvb, gint offset);
380 /** Find length of string by looking for end of string ('\0'), up to
381 * 'maxlength' characters'; if 'maxlength' is -1, searches to end
383 * Returns -1 if 'maxlength' reached before finding EOS. */
384 extern gint tvb_strnlen(tvbuff_t*, gint offset, guint maxlength);
386 /** Convert a string from Unicode to ASCII. At the moment we fake it by
387 * assuming all characters are ASCII )-: The caller must free the
388 * result returned. The len parameter is the number of guint16's to
389 * convert from Unicode. */
390 extern char *tvb_fake_unicode(tvbuff_t *tvb, int offset, int len,
391 gboolean little_endian);
394 * Format the data in the tvb from offset for size ...
396 extern gchar * tvb_format_text(tvbuff_t *tvb, gint offset, gint size);
399 * Like "tvb_format_text()", but for null-padded strings; don't show
400 * the null padding characters as "\000".
402 extern gchar *tvb_format_stringzpad(tvbuff_t *tvb, gint offset, gint size);
405 * Given a tvbuff, an offset, and a length, allocate a buffer big enough
406 * to hold a non-null-terminated string of that length at that offset,
407 * plus a trailing '\0', copy the string into it, and return a pointer
410 * Throws an exception if the tvbuff ends before the string does.
412 extern guint8 *tvb_get_string(tvbuff_t *tvb, gint offset, gint length);
415 * Given a tvbuff and an offset, with the offset assumed to refer to
416 * a null-terminated string, find the length of that string (and throw
417 * an exception if the tvbuff ends before we find the null), allocate
418 * a buffer big enough to hold the string, copy the string into it,
419 * and return a pointer to the string. Also return the length of the
420 * string (including the terminating null) through a pointer.
422 extern guint8 *tvb_get_stringz(tvbuff_t *tvb, gint offset, gint *lengthp);
424 /** Looks for a stringz (NUL-terminated string) in tvbuff and copies
425 * no more than bufsize number of bytes, including terminating NUL, to buffer.
426 * Returns length of string (not including terminating NUL), or -1 if the string was
427 * truncated in the buffer due to not having reached the terminating NUL.
428 * In this way, it acts like snprintf().
430 * When processing a packet where the remaining number of bytes is less
431 * than bufsize, an exception is not thrown if the end of the packet
432 * is reached before the NUL is found. If no NUL is found before reaching
433 * the end of the short packet, -1 is still returned, and the string
434 * is truncated with a NUL, albeit not at buffer[bufsize - 1], but
435 * at the correct spot, terminating the string.
437 extern gint tvb_get_nstringz(tvbuff_t *tvb, gint offset, guint bufsize,
440 /** Like tvb_get_nstringz(), but never returns -1. The string is guaranteed to
441 * have a terminating NUL. If the string was truncated when copied into buffer,
442 * a NUL is placed at the end of buffer to terminate it.
444 * bufsize MUST be greater than 0.
446 extern gint tvb_get_nstringz0(tvbuff_t *tvb, gint offset, guint bufsize,
450 * Given a tvbuff, an offset into the tvbuff, and a length that starts
451 * at that offset (which may be -1 for "all the way to the end of the
452 * tvbuff"), find the end of the (putative) line that starts at the
453 * specified offset in the tvbuff, going no further than the specified
456 * Return the length of the line (not counting the line terminator at
457 * the end), or, if we don't find a line terminator:
459 * if "deseg" is true, return -1;
461 * if "deseg" is false, return the amount of data remaining in
464 * Set "*next_offset" to the offset of the character past the line
465 * terminator, or past the end of the buffer if we don't find a line
466 * terminator. (It's not set if we return -1.)
468 extern gint tvb_find_line_end(tvbuff_t *tvb, gint offset, int len,
469 gint *next_offset, gboolean desegment);
472 * Given a tvbuff, an offset into the tvbuff, and a length that starts
473 * at that offset (which may be -1 for "all the way to the end of the
474 * tvbuff"), find the end of the (putative) line that starts at the
475 * specified offset in the tvbuff, going no further than the specified
478 * However, treat quoted strings inside the buffer specially - don't
479 * treat newlines in quoted strings as line terminators.
481 * Return the length of the line (not counting the line terminator at
482 * the end), or the amount of data remaining in the buffer if we don't
483 * find a line terminator.
485 * Set "*next_offset" to the offset of the character past the line
486 * terminator, or past the end of the buffer if we don't find a line
489 extern gint tvb_find_line_end_unquoted(tvbuff_t *tvb, gint offset, int len,
493 * Call strncmp after checking if enough chars left, returning 0 if
494 * it returns 0 (meaning "equal") and -1 otherwise, otherwise return -1.
496 extern gint tvb_strneql(tvbuff_t *tvb, gint offset, const gchar *str,
500 * Call strncasecmp after checking if enough chars left, returning 0 if
501 * it returns 0 (meaning "equal") and -1 otherwise, otherwise return -1.
503 extern gint tvb_strncaseeql(tvbuff_t *tvb, gint offset, const gchar *str,
507 * Call memcmp after checking if enough chars left, returning 0 if
508 * it returns 0 (meaning "equal") and -1 otherwise, otherwise return -1.
510 extern gint tvb_memeql(tvbuff_t *tvb, gint offset, const guint8 *str,
514 * Format a bunch of data from a tvbuff as bytes, returning a pointer
515 * to the string with the formatted data, with "punct" as a byte
518 extern gchar *tvb_bytes_to_str_punct(tvbuff_t *tvb, gint offset, gint len,
522 * Format a bunch of data from a tvbuff as bytes, returning a pointer
523 * to the string with the formatted data.
525 extern gchar *tvb_bytes_to_str(tvbuff_t *tvb, gint offset, gint len);
527 #define TVB_GET_DS_TVB(tvb) \
530 /** Locate a sub-tvbuff within another tvbuff, starting at position
531 * 'haystack_offset'. Returns the index of the beginning of 'needle' within
532 * 'haystack', or -1 if 'needle' is not found. The index is relative
533 * to the start of 'haystack', not 'haystack_offset'. */
534 extern gint tvb_find_tvb(tvbuff_t *haystack_tvb, tvbuff_t *needle_tvb,
535 gint haystack_offset);
538 * Uncompresses a zlib compressed packet inside a tvbuff at offset with
539 * length comprlen. Returns an uncompressed tvbuffer if uncompression
540 * succeeded or NULL if uncompression failed.
542 extern tvbuff_t* tvb_uncompress(tvbuff_t *tvb, int offset, int comprlen);
544 /************** END OF ACCESSORS ****************/
546 #endif /* __TVBUFF_H__ */