2 This file is part of GNUnet.
3 (C) 2009-2011 Christian Grothoff (and other contributing authors)
5 GNUnet is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published
7 by the Free Software Foundation; either version 3, or (at your
8 option) any later version.
10 GNUnet is distributed in the hope that it will be useful, but
11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with GNUnet; see the file COPYING. If not, write to the
17 Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA.
22 * @brief Merkle-tree-ish-CHK file encoding for GNUnet
23 * @see http://gnunet.org/encoding.php3
24 * @author Krista Bennett
25 * @author Christian Grothoff
30 #define DEBUG_TREE GNUNET_NO
33 * Context for an ECRS-based file encoder that computes
34 * the Merkle-ish-CHK tree.
36 struct GNUNET_FS_TreeEncoder
42 struct GNUNET_FS_Handle *h;
45 * Closure for all callbacks.
50 * Function to call on encrypted blocks.
52 GNUNET_FS_TreeBlockProcessor proc;
55 * Function to call with progress information.
57 GNUNET_FS_TreeProgressCallback progress;
60 * Function to call to receive input data.
62 GNUNET_FS_DataReader reader;
65 * Function to call once we're done with processing.
67 GNUNET_SCHEDULER_Task cont;
70 * Set to an error message (if we had an error).
75 * Set to the URI (upon successful completion)
77 struct GNUNET_FS_Uri *uri;
87 uint64_t publish_offset;
90 * How deep are we? Depth 0 is for the DBLOCKs.
92 unsigned int current_depth;
95 * How deep is the tree? Always > 0.
97 unsigned int chk_tree_depth;
100 * In-memory cache of the current CHK tree.
101 * This struct will contain the CHK values
102 * from the root to the currently processed
103 * node in the tree as identified by
104 * "current_depth" and "publish_offset".
105 * The "chktree" will be initially NULL,
106 * then allocated to a sufficient number of
107 * entries for the size of the file and
108 * finally freed once the upload is complete.
110 struct ContentHashKey *chk_tree;
113 * Are we currently in 'GNUNET_FS_tree_encoder_next'?
114 * Flag used to prevent recursion.
121 * Compute the depth of the CHK tree.
123 * @param flen file length for which to compute the depth
124 * @return depth of the tree, always > 0. A depth of 1 means only a DBLOCK.
127 GNUNET_FS_compute_depth (uint64_t flen)
129 unsigned int treeDepth;
137 if (fl * CHK_PER_INODE < fl)
139 /* integer overflow, this is a HUGE file... */
142 fl = fl * CHK_PER_INODE;
149 * Calculate how many bytes of payload a block tree of the given
150 * depth MAY correspond to at most (this function ignores the fact that
151 * some blocks will only be present partially due to the total file
152 * size cutting some blocks off at the end).
154 * @param depth depth of the block. depth==0 is a DBLOCK.
155 * @return number of bytes of payload a subtree of this depth may correspond to
158 GNUNET_FS_tree_compute_tree_size (unsigned int depth)
164 for (i = 0; i<depth; i++)
165 rsize *= CHK_PER_INODE;
171 * Compute the size of the current IBLOCK. The encoder is
172 * triggering the calculation of the size of an IBLOCK at the
173 * *end* (hence end_offset) of its construction. The IBLOCK
174 * maybe a full or a partial IBLOCK, and this function is to
175 * calculate how long it should be.
177 * @param depth depth of the IBlock in the tree, 0 would be a DBLOCK,
178 * must be > 0 (this function is for IBLOCKs only!)
179 * @param end_offset current offset in the payload (!) of the overall file,
180 * must be > 0 (since this function is called at the
182 * @return size of the corresponding IBlock
185 GNUNET_FS_tree_compute_iblock_size (unsigned int depth,
192 GNUNET_assert (depth > 0);
193 GNUNET_assert (end_offset > 0);
194 bds = GNUNET_FS_tree_compute_tree_size (depth);
195 mod = end_offset % bds;
198 /* we were triggered at the end of a full block */
203 /* we were triggered at the end of the file */
204 bds /= CHK_PER_INODE;
209 return (uint16_t) (ret * sizeof(struct ContentHashKey));
214 * Compute how many bytes of data should be stored in
215 * the specified block.
217 * @param fsize overall file size, must be > 0.
218 * @param offset offset in the original data corresponding
219 * to the beginning of the tree induced by the block;
221 * @param depth depth of the node in the tree, 0 for DBLOCK
222 * @return number of bytes stored in this node
225 GNUNET_FS_tree_calculate_block_size (uint64_t fsize,
234 GNUNET_assert (fsize > 0);
235 GNUNET_assert (offset <= fsize);
239 if ( (offset + ret > fsize) ||
240 (offset + ret < offset) )
241 ret = (size_t) (fsize - offset);
245 rsize = GNUNET_FS_tree_compute_tree_size (depth - 1);
246 epos = offset + rsize * CHK_PER_INODE;
247 if ( (epos < offset) ||
250 /* round up when computing #CHKs in our IBlock */
251 chks = (epos - offset + rsize - 1) / rsize;
252 GNUNET_assert (chks <= CHK_PER_INODE);
253 return chks * sizeof (struct ContentHashKey);
258 * Initialize a tree encoder. This function will call "proc" and
259 * "progress" on each block in the tree. Once all blocks have been
260 * processed, "cont" will be scheduled. The "reader" will be called
261 * to obtain the (plaintext) blocks for the file. Note that this
262 * function will not actually call "proc". The client must
263 * call "GNUNET_FS_tree_encoder_next" to trigger encryption (and
264 * calling of "proc") for the each block.
266 * @param h the global FS context
267 * @param size overall size of the file to encode
268 * @param cls closure for reader, proc, progress and cont
269 * @param reader function to call to read plaintext data
270 * @param proc function to call on each encrypted block
271 * @param progress function to call with progress information
272 * @param cont function to call when done
274 struct GNUNET_FS_TreeEncoder *
275 GNUNET_FS_tree_encoder_create (struct GNUNET_FS_Handle *h,
278 GNUNET_FS_DataReader reader,
279 GNUNET_FS_TreeBlockProcessor proc,
280 GNUNET_FS_TreeProgressCallback progress,
281 GNUNET_SCHEDULER_Task cont)
283 struct GNUNET_FS_TreeEncoder *te;
285 te = GNUNET_malloc (sizeof (struct GNUNET_FS_TreeEncoder));
291 te->progress = progress;
293 te->chk_tree_depth = GNUNET_FS_compute_depth (size);
294 te->chk_tree = GNUNET_malloc (te->chk_tree_depth *
296 sizeof (struct ContentHashKey));
302 * Compute the offset of the CHK for the
303 * current block in the IBlock above.
305 * @param depth depth of the IBlock in the tree (aka overall
306 * number of tree levels minus depth); 0 == DBlock
307 * @param end_offset current offset in the overall file,
308 * at the *beginning* of the block for DBLOCKs (depth==0),
309 * otherwise at the *end* of the block (exclusive)
310 * @return (array of CHKs') offset in the above IBlock
313 compute_chk_offset (unsigned int depth,
319 bds = GNUNET_FS_tree_compute_tree_size (depth);
321 end_offset--; /* round down since for depth > 0 offset is at the END of the block */
322 ret = end_offset / bds;
323 return ret % CHK_PER_INODE;
328 * Encrypt the next block of the file (and call proc and progress
329 * accordingly; or of course "cont" if we have already completed
330 * encoding of the entire file).
332 * @param te tree encoder to use
335 GNUNET_FS_tree_encoder_next (struct GNUNET_FS_TreeEncoder * te)
337 struct ContentHashKey *mychk;
338 const void *pt_block;
340 char iob[DBLOCK_SIZE];
341 char enc[DBLOCK_SIZE];
342 struct GNUNET_CRYPTO_AesSessionKey sk;
343 struct GNUNET_CRYPTO_AesInitializationVector iv;
346 GNUNET_assert (GNUNET_NO == te->in_next);
347 te->in_next = GNUNET_YES;
348 if (te->chk_tree_depth == te->current_depth)
350 off = CHK_PER_INODE * (te->chk_tree_depth - 1);
352 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
353 "TE done, reading CHK `%s' from %u\n",
354 GNUNET_h2s (&te->chk_tree[off].query),
357 te->uri = GNUNET_malloc (sizeof(struct GNUNET_FS_Uri));
359 te->uri->data.chk.chk = te->chk_tree[off];
360 te->uri->data.chk.file_length = GNUNET_htonll (te->size);
361 te->in_next = GNUNET_NO;
362 te->cont (te->cls, NULL);
365 if (0 == te->current_depth)
368 pt_size = GNUNET_MIN(DBLOCK_SIZE,
369 te->size - te->publish_offset);
377 GNUNET_SCHEDULER_add_continuation (te->cont,
379 GNUNET_SCHEDULER_REASON_TIMEOUT);
380 te->in_next = GNUNET_NO;
387 pt_size = GNUNET_FS_tree_compute_iblock_size (te->current_depth,
389 pt_block = &te->chk_tree[(te->current_depth - 1) *
392 off = compute_chk_offset (te->current_depth,
395 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
396 "TE is at offset %llu and depth %u with block size %u and target-CHK-offset %u\n",
397 (unsigned long long) te->publish_offset,
399 (unsigned int) pt_size,
402 mychk = &te->chk_tree[te->current_depth*CHK_PER_INODE+off];
403 GNUNET_CRYPTO_hash (pt_block, pt_size, &mychk->key);
404 GNUNET_CRYPTO_hash_to_aes_key (&mychk->key, &sk, &iv);
405 GNUNET_CRYPTO_aes_encrypt (pt_block,
410 GNUNET_CRYPTO_hash (enc, pt_size, &mychk->query);
412 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
413 "TE calculates query to be `%s', stored at %u\n",
414 GNUNET_h2s (&mychk->query),
415 te->current_depth * CHK_PER_INODE + off);
417 if (NULL != te->proc)
422 (0 == te->current_depth)
423 ? GNUNET_BLOCK_TYPE_FS_DBLOCK
424 : GNUNET_BLOCK_TYPE_FS_IBLOCK,
427 if (NULL != te->progress)
428 te->progress (te->cls,
433 if (0 == te->current_depth)
435 te->publish_offset += pt_size;
436 if ( (te->publish_offset == te->size) ||
437 (0 == te->publish_offset % (CHK_PER_INODE * DBLOCK_SIZE) ) )
442 if ( (off == CHK_PER_INODE) ||
443 (te->publish_offset == te->size) )
446 te->current_depth = 0;
448 te->in_next = GNUNET_NO;
453 * Clean up a tree encoder and return information
454 * about the resulting URI or an error message.
456 * @param te the tree encoder to clean up
457 * @param uri set to the resulting URI (if encoding finished)
458 * @param emsg set to an error message (if an error occured
459 * within the tree encoder; if this function is called
460 * prior to completion and prior to an internal error,
461 * both "*uri" and "*emsg" will be set to NULL).
463 void GNUNET_FS_tree_encoder_finish (struct GNUNET_FS_TreeEncoder *te,
464 struct GNUNET_FS_Uri **uri,
467 GNUNET_assert (GNUNET_NO == te->in_next);
472 GNUNET_FS_uri_destroy (te->uri);
476 GNUNET_free_non_null (te->emsg);
477 GNUNET_free (te->chk_tree);
481 /* end of fs_tree.c */