2 This file is part of GNUnet.
3 (C) 2009 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 2, 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
28 * - decide if this API should be made public (gnunet_fs_service.h)
29 * or remain "internal" (but with exported symbols?)
36 * Context for an ECRS-based file encoder that computes
37 * the Merkle-ish-CHK tree.
39 struct GNUNET_FS_TreeEncoder
45 struct GNUNET_FS_Handle *h;
48 * Closure for all callbacks.
53 * Function to call on encrypted blocks.
55 GNUNET_FS_TreeBlockProcessor proc;
58 * Function to call with progress information.
60 GNUNET_FS_TreeProgressCallback progress;
63 * Function to call to receive input data.
65 GNUNET_FS_DataReader reader;
68 * Function to call once we're done with processing.
70 GNUNET_SCHEDULER_Task cont;
73 * Set to an error message (if we had an error).
78 * Set to the URI (upon successful completion)
80 struct GNUNET_FS_Uri *uri;
90 uint64_t publish_offset;
95 unsigned int current_depth;
98 * How deep is the tree?
100 unsigned int chk_tree_depth;
103 * In-memory cache of the current CHK tree.
104 * This struct will contain the CHK values
105 * from the root to the currently processed
106 * node in the tree as identified by
107 * "current_depth" and "publish_offset".
108 * The "chktree" will be initially NULL,
109 * then allocated to a sufficient number of
110 * entries for the size of the file and
111 * finally freed once the upload is complete.
113 struct ContentHashKey *chk_tree;
119 * Compute the depth of the CHK tree.
121 * @param flen file length for which to compute the depth
122 * @return depth of the tree
125 GNUNET_FS_compute_depth (uint64_t flen)
127 unsigned int treeDepth;
135 if (fl * CHK_PER_INODE < fl)
137 /* integer overflow, this is a HUGE file... */
140 fl = fl * CHK_PER_INODE;
147 * Initialize a tree encoder. This function will call "proc" and
148 * "progress" on each block in the tree. Once all blocks have been
149 * processed, "cont" will be scheduled. The "reader" will be called
150 * to obtain the (plaintext) blocks for the file. Note that this
151 * function will not actually call "proc". The client must
152 * call "GNUNET_FS_tree_encoder_next" to trigger encryption (and
153 * calling of "proc") for the each block.
155 * @param h the global FS context
156 * @param size overall size of the file to encode
157 * @param cls closure for reader, proc, progress and cont
158 * @param reader function to call to read plaintext data
159 * @param proc function to call on each encrypted block
160 * @param progress function to call with progress information
161 * @param cont function to call when done
163 struct GNUNET_FS_TreeEncoder *
164 GNUNET_FS_tree_encoder_create (struct GNUNET_FS_Handle *h,
167 GNUNET_FS_DataReader reader,
168 GNUNET_FS_TreeBlockProcessor proc,
169 GNUNET_FS_TreeProgressCallback progress,
170 GNUNET_SCHEDULER_Task cont)
172 struct GNUNET_FS_TreeEncoder *te;
174 te = GNUNET_malloc (sizeof (struct GNUNET_FS_TreeEncoder));
180 te->progress = progress;
182 te->chk_tree_depth = GNUNET_FS_compute_depth (size);
183 te->current_depth = te->chk_tree_depth;
184 te->chk_tree = GNUNET_malloc (te->chk_tree_depth *
186 sizeof (struct ContentHashKey));
192 * Compute the size of the current IBlock.
194 * @param height height of the IBlock in the tree (aka overall
195 * number of tree levels minus depth); 0 == DBlock
196 * @param offset current offset in the overall file
197 * @return size of the corresponding IBlock
200 compute_iblock_size (unsigned int height,
208 GNUNET_assert (height > 0);
209 bds = DBLOCK_SIZE; /* number of bytes each CHK at level "i"
211 for (i=0;i<height;i++)
212 bds *= CHK_PER_INODE;
216 /* we were triggered at the end of a full block */
221 /* we were triggered at the end of the file */
222 bds /= CHK_PER_INODE;
227 return (uint16_t) (ret * sizeof(struct ContentHashKey));
232 * Compute the offset of the CHK for the
233 * current block in the IBlock above.
235 * @param height height of the IBlock in the tree (aka overall
236 * number of tree levels minus depth); 0 == DBlock
237 * @param offset current offset in the overall file
238 * @return (array of CHKs') offset in the above IBlock
241 compute_chk_offset (unsigned int height,
248 bds = DBLOCK_SIZE; /* number of bytes each CHK at level "i"
250 for (i=0;i<height;i++)
251 bds *= CHK_PER_INODE;
252 GNUNET_assert (0 == (offset % bds));
254 return ret % CHK_PER_INODE;
259 * Encrypt the next block of the file (and
260 * call proc and progress accordingly; or
261 * of course "cont" if we have already completed
262 * encoding of the entire file).
264 * @param te tree encoder to use
266 void GNUNET_FS_tree_encoder_next (struct GNUNET_FS_TreeEncoder * te)
268 struct ContentHashKey *mychk;
269 const void *pt_block;
271 char iob[DBLOCK_SIZE];
272 char enc[DBLOCK_SIZE];
273 struct GNUNET_CRYPTO_AesSessionKey sk;
274 struct GNUNET_CRYPTO_AesInitializationVector iv;
277 if (te->current_depth == te->chk_tree_depth)
279 pt_size = GNUNET_MIN(DBLOCK_SIZE,
280 te->size - te->publish_offset);
288 GNUNET_SCHEDULER_add_continuation (te->h->sched,
292 GNUNET_SCHEDULER_REASON_TIMEOUT);
299 pt_size = compute_iblock_size (te->chk_tree_depth - te->current_depth,
301 pt_block = &te->chk_tree[te->current_depth *
304 off = compute_chk_offset (te->chk_tree_depth - te->current_depth,
306 mychk = &te->chk_tree[(te->current_depth-1)*CHK_PER_INODE+off];
307 GNUNET_CRYPTO_hash (pt_block, pt_size, &mychk->key);
308 GNUNET_CRYPTO_hash_to_aes_key (&mychk->key, &sk, &iv);
309 GNUNET_CRYPTO_aes_encrypt (pt_block,
314 if (NULL != te->proc)
320 (te->current_depth == te->chk_tree_depth)
321 ? GNUNET_DATASTORE_BLOCKTYPE_DBLOCK
322 : GNUNET_DATASTORE_BLOCKTYPE_IBLOCK);
323 if (NULL != te->progress)
324 te->progress (te->cls,
329 GNUNET_CRYPTO_hash (enc, pt_size, &mychk->query);
330 if (te->current_depth == te->chk_tree_depth)
332 te->publish_offset += pt_size;
333 if ( (te->publish_offset == te->size) ||
334 (0 == te->publish_offset % (CHK_PER_INODE * DBLOCK_SIZE) ) )
339 if ( (off == CHK_PER_INODE) ||
340 (te->publish_offset == te->size) )
343 te->current_depth = te->chk_tree_depth;
345 if (0 == te->current_depth)
347 te->uri = GNUNET_malloc (sizeof(struct GNUNET_FS_Uri));
349 te->uri->data.chk.chk = te->chk_tree[0];
350 te->uri->data.chk.file_length = GNUNET_htonll (te->size);
351 GNUNET_SCHEDULER_add_continuation (te->h->sched,
355 GNUNET_SCHEDULER_REASON_PREREQ_DONE);
361 * Clean up a tree encoder and return information
362 * about the resulting URI or an error message.
364 * @param te the tree encoder to clean up
365 * @param uri set to the resulting URI (if encoding finished)
366 * @param emsg set to an error message (if an error occured
367 * within the tree encoder; if this function is called
368 * prior to completion and prior to an internal error,
369 * both "*uri" and "*emsg" will be set to NULL).
371 void GNUNET_FS_tree_encoder_finish (struct GNUNET_FS_TreeEncoder * te,
372 struct GNUNET_FS_Uri **uri,
377 GNUNET_free (te->chk_tree);
381 /* end of fs_tree.c */