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3 (C) 2012,2013 Christian Grothoff (and other contributing authors)
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7 by the Free Software Foundation; either version 3, or (at your
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12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
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21 * @author Bartlomiej Polot
22 * @file regex/regex_block_lib.c
23 * @brief functions for manipulating non-accept blocks stored for
27 #include "regex_block_lib.h"
28 #include "gnunet_constants.h"
30 #define LOG(kind,...) GNUNET_log_from (kind,"regex-bck",__VA_ARGS__)
32 GNUNET_NETWORK_STRUCT_BEGIN
35 * Information for each edge.
40 * Index of the destination of this edge in the
41 * unique destinations array.
43 uint16_t destination_index GNUNET_PACKED;
46 * Number of bytes the token for this edge takes in the
49 uint16_t token_length GNUNET_PACKED;
54 * @brief Block to announce a regex state.
60 * Length of the proof regex string.
62 uint16_t proof_len GNUNET_PACKED;
65 * Is this state an accepting state?
67 int16_t is_accepting GNUNET_PACKED;
70 * Number of edges parting from this state.
72 uint16_t num_edges GNUNET_PACKED;
75 * Nubmer of unique destinations reachable from this state.
77 uint16_t num_destinations GNUNET_PACKED;
79 /* followed by 'struct GNUNET_HashCode[num_destinations]' */
81 /* followed by 'struct EdgeInfo[edge_destination_indices]' */
83 /* followed by 'char proof[n_proof]', NOT 0-terminated */
85 /* followed by 'char tokens[num_edges][edge_info[k].token_length]';
86 essentially all of the tokens one after the other in the
87 order of the edges; tokens are NOT 0-terminated */
92 GNUNET_NETWORK_STRUCT_END
96 * Test if this block is marked as being an accept state.
98 * @param block block to test
99 * @param size number of bytes in block
100 * @return GNUNET_YES if the block is accepting, GNUNET_NO if not
103 GNUNET_BLOCK_is_accepting (const struct RegexBlock *block,
106 if (size < sizeof (struct RegexBlock))
109 return GNUNET_SYSERR;
111 return ntohs (block->is_accepting);
116 * Check if the given 'proof' matches the given 'key'.
118 * @param proof partial regex of a state
119 * @param proof_len number of bytes in 'proof'
120 * @param key hash of a state.
122 * @return GNUNET_OK if the proof is valid for the given key.
125 REGEX_BLOCK_check_proof (const char *proof,
127 const struct GNUNET_HashCode *key)
129 struct GNUNET_HashCode key_check;
131 if ( (NULL == proof) || (NULL == key))
133 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Proof check failed, was NULL.\n");
136 GNUNET_CRYPTO_hash (proof, proof_len, &key_check);
138 GNUNET_CRYPTO_hash_cmp (key, &key_check)) ? GNUNET_OK : GNUNET_NO;
143 * Struct to keep track of the xquery while iterating all the edges in a block.
145 struct CheckEdgeContext
148 * Xquery: string we are looking for.
153 * Has any edge matched the xquery so far? (GNUNET_OK / GNUNET_NO)
161 * Iterator over all edges in a block, checking for a presence of a given query.
163 * @param cls Closure, (xquery context).
164 * @param token Token that follows to next state.
165 * @param len Lenght of token.
166 * @param key Hash of next state.
168 * @return GNUNET_YES, to keep iterating
171 check_edge (void *cls,
174 const struct GNUNET_HashCode *key)
176 struct CheckEdgeContext *ctx = cls;
178 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
179 "edge %.*s [%u]: %s->%s\n",
180 (int) len, token, len, GNUNET_h2s(key));
181 if (NULL == ctx->xquery)
183 if (strlen (ctx->xquery) < len)
184 return GNUNET_YES; /* too long */
185 if (0 == strncmp (ctx->xquery, token, len))
186 ctx->found = GNUNET_OK;
187 return GNUNET_YES; /* keep checking for malformed data! */
192 * Check if the regex block is well formed, including all edges.
194 * @param block The start of the block.
195 * @param size The size of the block.
196 * @param query the query for the block
197 * @param xquery String describing the edge we are looking for.
198 * Can be NULL in case this is a put block.
200 * @return GNUNET_OK in case it's fine.
201 * GNUNET_NO in case the xquery exists and is not found (IRRELEVANT).
202 * GNUNET_SYSERR if the block is invalid.
205 REGEX_BLOCK_check (const struct RegexBlock *block,
207 const struct GNUNET_HashCode *query,
210 struct GNUNET_HashCode key;
211 struct CheckEdgeContext ctx;
215 REGEX_BLOCK_get_key (block, size,
219 return GNUNET_SYSERR;
221 if (0 != memcmp (&key,
223 sizeof (struct GNUNET_HashCode)))
226 return GNUNET_SYSERR;
228 if ( (GNUNET_YES == ntohs (block->is_accepting)) &&
229 ( (NULL == xquery) || ('\0' == xquery[0]) ) )
232 ctx.found = GNUNET_NO;
233 res = REGEX_BLOCK_iterate (block, size, &check_edge, &ctx);
234 if (GNUNET_SYSERR == res)
235 return GNUNET_SYSERR;
243 * Obtain the key that a particular block is to be stored under.
245 * @param block block to get the key from
246 * @param block_len number of bytes in block
247 * @param key where to store the key
248 * @return GNUNET_OK on success, GNUNET_SYSERR if the block is malformed
251 REGEX_BLOCK_get_key (const struct RegexBlock *block,
253 struct GNUNET_HashCode *key)
256 const struct GNUNET_HashCode *destinations;
257 const struct EdgeInfo *edges;
258 uint16_t num_destinations;
262 if (block_len < sizeof (struct RegexBlock))
265 return GNUNET_SYSERR;
267 num_destinations = ntohs (block->num_destinations);
268 num_edges = ntohs (block->num_edges);
269 len = ntohs (block->proof_len);
270 destinations = (const struct GNUNET_HashCode *) &block[1];
271 edges = (const struct EdgeInfo *) &destinations[num_destinations];
272 total = sizeof (struct RegexBlock) + num_destinations * sizeof (struct GNUNET_HashCode) + num_edges + sizeof (struct EdgeInfo) + len;
273 if (block_len < total)
276 return GNUNET_SYSERR;
278 GNUNET_CRYPTO_hash (&edges[num_edges], len, key);
284 * Iterate over all edges of a block of a regex state.
286 * @param block Block to iterate over.
287 * @param size Size of block.
288 * @param iterator Function to call on each edge in the block.
289 * @param iter_cls Closure for the iterator.
291 * @return GNUNET_SYSERR if an error has been encountered.
292 * GNUNET_OK if no error has been encountered.
293 * Note that if the iterator stops the iteration by returning
294 * GNUNET_NO, the block will no longer be checked for further errors.
295 * The return value will be GNUNET_OK meaning that no errors were
296 * found until the edge last notified to the iterator, but there might
297 * be errors in further edges.
300 REGEX_BLOCK_iterate (const struct RegexBlock *block,
302 REGEX_INTERNAL_EgdeIterator iterator,
306 const struct GNUNET_HashCode *destinations;
307 const struct EdgeInfo *edges;
309 uint16_t num_destinations;
315 if (size < sizeof (struct RegexBlock))
318 return GNUNET_SYSERR;
320 num_destinations = ntohs (block->num_destinations);
321 num_edges = ntohs (block->num_edges);
322 len = ntohs (block->proof_len);
323 destinations = (const struct GNUNET_HashCode *) &block[1];
324 edges = (const struct EdgeInfo *) &destinations[num_destinations];
325 aux = (const char *) &edges[num_edges];
326 total = sizeof (struct RegexBlock) + num_destinations * sizeof (struct GNUNET_HashCode) + num_edges * sizeof (struct EdgeInfo) + len;
330 return GNUNET_SYSERR;
332 for (n=0;n<num_edges;n++)
333 total += ntohs (edges[n].token_length);
336 fprintf (stderr, "Expected %u, got %u\n",
338 (unsigned int) total);
340 return GNUNET_SYSERR;
343 LOG (GNUNET_ERROR_TYPE_DEBUG,
344 "Start iterating block of size %u, proof %u, off %u edges %u\n",
346 /* &aux[off] always points to our token */
347 for (n=0;n<num_edges;n++)
349 LOG (GNUNET_ERROR_TYPE_DEBUG,
350 "Edge %u, off %u tokenlen %u\n", n, off,
351 ntohs (edges[n].token_length));
352 if (NULL != iterator)
353 if (GNUNET_NO == iterator (iter_cls,
355 ntohs (edges[n].token_length),
356 &destinations[ntohs (edges[n].destination_index)]))
358 off += ntohs (edges[n].token_length);
365 * Construct a regex block to be stored in the DHT.
367 * @param proof proof string for the block
368 * @param num_edges number of edges in the block
369 * @param edges the edges of the block
370 * @param accepting is this an accepting state
371 * @param rsize set to the size of the returned block (OUT-only)
372 * @return the regex block, NULL on error
375 REGEX_BLOCK_create (const char *proof,
376 unsigned int num_edges,
377 const struct REGEX_BLOCK_Edge *edges,
381 struct RegexBlock *block;
382 struct GNUNET_HashCode destinations[1024]; /* 1024 = 64k/64 bytes/key == absolute MAX */
383 uint16_t destination_indices[num_edges];
384 struct GNUNET_HashCode *dests;
385 struct EdgeInfo *edgeinfos;
390 unsigned int unique_destinations;
395 len = strlen (proof);
396 if (len > UINT16_MAX)
401 unique_destinations = 0;
402 total = sizeof (struct RegexBlock) + len;
403 for (i=0;i<num_edges;i++)
405 slen = strlen (edges[i].label);
406 if (len > UINT16_MAX)
412 for (j=0;j<unique_destinations;j++)
413 if (0 == memcmp (&destinations[j],
414 &edges[i].destination,
415 sizeof (struct GNUNET_HashCode)))
422 destination_indices[i] = j;
423 if (j == unique_destinations)
424 destinations[unique_destinations++] = edges[i].destination;
426 total += num_edges * sizeof (struct EdgeInfo) + unique_destinations * sizeof (struct GNUNET_HashCode);
427 if (total >= GNUNET_CONSTANTS_MAX_BLOCK_SIZE)
432 block = GNUNET_malloc (total);
433 block->proof_len = htons (len);
434 block->is_accepting = htons (accepting);
435 block->num_edges = htons (num_edges);
436 block->num_destinations = htons (unique_destinations);
437 dests = (struct GNUNET_HashCode *) &block[1];
438 memcpy (dests, destinations, sizeof (struct GNUNET_HashCode) * unique_destinations);
439 edgeinfos = (struct EdgeInfo *) &dests[unique_destinations];
440 aux = (char *) &edgeinfos[num_edges];
442 memcpy (aux, proof, len);
443 for (i=0;i<num_edges;i++)
445 slen = strlen (edges[i].label);
446 edgeinfos[i].token_length = htons ((uint16_t) slen);
447 edgeinfos[i].destination_index = htons (destination_indices[i]);
458 /* end of regex_block_lib.c */