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20 * @file namecache/namecache_api.c
21 * @brief API to access the NAMECACHE service
22 * @author Martin Schanzenbach
23 * @author Matthias Wachs
24 * @author Christian Grothoff
28 #include "gnunet_util_lib.h"
29 #include "gnunet_crypto_lib.h"
30 #include "gnunet_constants.h"
31 #include "gnunet_dnsparser_lib.h"
32 #include "gnunet_gnsrecord_lib.h"
33 #include "gnunet_signatures.h"
34 #include "gnunet_namecache_service.h"
35 #include "namecache.h"
38 #define LOG(kind,...) GNUNET_log_from (kind, "namecache-api",__VA_ARGS__)
42 * An QueueEntry used to store information for a pending
43 * NAMECACHE record operation
45 struct GNUNET_NAMECACHE_QueueEntry
51 struct GNUNET_NAMECACHE_QueueEntry *next;
56 struct GNUNET_NAMECACHE_QueueEntry *prev;
59 * Main handle to access the namecache.
61 struct GNUNET_NAMECACHE_Handle *nsh;
64 * Continuation to call
66 GNUNET_NAMECACHE_ContinuationWithStatus cont;
69 * Closure for @e cont.
74 * Function to call with the blocks we get back; or NULL.
76 GNUNET_NAMECACHE_BlockProcessor block_proc;
79 * Closure for @e block_proc.
84 * The operation id this zone iteration operation has
92 * Connection to the NAMECACHE service.
94 struct GNUNET_NAMECACHE_Handle
98 * Configuration to use.
100 const struct GNUNET_CONFIGURATION_Handle *cfg;
103 * Message queue to service.
105 struct GNUNET_MQ_Handle *mq;
108 * Currently pending transmission request (or NULL).
110 struct GNUNET_CLIENT_TransmitHandle *th;
113 * Head of pending namecache queue entries
115 struct GNUNET_NAMECACHE_QueueEntry *op_head;
118 * Tail of pending namecache queue entries
120 struct GNUNET_NAMECACHE_QueueEntry *op_tail;
125 struct GNUNET_SCHEDULER_Task *reconnect_task;
128 * Delay introduced before we reconnect.
130 struct GNUNET_TIME_Relative reconnect_delay;
133 * Should we reconnect to service due to some serious error?
138 * The last operation id used for a NAMECACHE operation
140 uint32_t last_op_id_used;
146 * Disconnect from service and then reconnect.
148 * @param h our handle
151 force_reconnect (struct GNUNET_NAMECACHE_Handle *h);
155 * Find queue entry for the given @a rid.
157 * @param h handle to search
158 * @param rid request ID to look for
159 * @return NULL if not found, otherwise the queue entry (removed from the queue)
161 static struct GNUNET_NAMECACHE_QueueEntry *
162 find_qe (struct GNUNET_NAMECACHE_Handle *h,
165 struct GNUNET_NAMECACHE_QueueEntry *qe;
167 for (qe = h->op_head; qe != NULL; qe = qe->next)
169 if (qe->op_id == rid)
171 GNUNET_CONTAINER_DLL_remove (h->op_head,
182 * Handle an incoming message of type
183 * #GNUNET_MESSAGE_TYPE_NAMECACHE_LOOKUP_BLOCK_RESPONSE.
185 * @param cls the `struct GNUNET_NAMECACHE_Handle`
186 * @param msg the message we received
189 check_lookup_block_response (void *cls,
190 const struct LookupBlockResponseMessage *msg)
192 /* any length will do, format validation is in handler */
198 * Handle an incoming message of type
199 * #GNUNET_MESSAGE_TYPE_NAMECACHE_LOOKUP_BLOCK_RESPONSE.
201 * @param cls the `struct GNUNET_NAMECACHE_Handle`
202 * @param msg the message we received
205 handle_lookup_block_response (void *cls,
206 const struct LookupBlockResponseMessage *msg)
208 struct GNUNET_NAMECACHE_Handle *h = cls;
210 struct GNUNET_NAMECACHE_QueueEntry *qe;
212 LOG (GNUNET_ERROR_TYPE_DEBUG,
213 "Received LOOKUP_BLOCK_RESPONSE\n");
215 ntohl (msg->gns_header.r_id));
218 if (0 == GNUNET_TIME_absolute_ntoh (msg->expire).abs_value_us)
221 if (NULL != qe->block_proc)
222 qe->block_proc (qe->block_proc_cls,
227 if (ntohs (msg->gns_header.header.size) < sizeof (struct LookupBlockResponseMessage))
229 LOG (GNUNET_ERROR_TYPE_ERROR,
230 "Message is too short\n");
233 size = ntohs (msg->gns_header.header.size)
234 - sizeof (struct LookupBlockResponseMessage);
236 char buf[size + sizeof (struct GNUNET_GNSRECORD_Block)] GNUNET_ALIGN;
237 struct GNUNET_GNSRECORD_Block *block;
239 block = (struct GNUNET_GNSRECORD_Block *) buf;
240 block->signature = msg->signature;
241 block->derived_key = msg->derived_key;
242 block->purpose.purpose = htonl (GNUNET_SIGNATURE_PURPOSE_GNS_RECORD_SIGN);
243 block->purpose.size = htonl (size +
244 sizeof (struct GNUNET_TIME_AbsoluteNBO) +
245 sizeof (struct GNUNET_CRYPTO_EccSignaturePurpose));
246 block->expiration_time = msg->expire;
247 GNUNET_memcpy (&block[1],
251 GNUNET_GNSRECORD_block_verify (block))
254 if (NULL != qe->block_proc)
255 qe->block_proc (qe->block_proc_cls,
261 if (NULL != qe->block_proc)
262 qe->block_proc (qe->block_proc_cls,
271 * Handle an incoming message of type
272 * #GNUNET_MESSAGE_TYPE_NAMECACHE_BLOCK_CACHE_RESPONSE
274 * @param cls the `struct GNUNET_NAMECACHE_Handle`
275 * @param msg the message we received
276 * @param size the message size
277 * @return #GNUNET_OK on success, #GNUNET_SYSERR on error and we did NOT notify the client
280 handle_block_cache_response (void *cls,
281 const struct BlockCacheResponseMessage *msg)
283 struct GNUNET_NAMECACHE_Handle *h = cls;
284 struct GNUNET_NAMECACHE_QueueEntry *qe;
287 LOG (GNUNET_ERROR_TYPE_DEBUG,
288 "Received BLOCK_CACHE_RESPONSE\n");
290 ntohl (msg->gns_header.r_id));
293 res = ntohl (msg->op_result);
294 /* TODO: add actual error message from namecache to response... */
295 if (NULL != qe->cont)
296 qe->cont (qe->cont_cls,
300 : _("Namecache failed to cache block"));
306 * Generic error handler, called with the appropriate error code and
307 * the same closure specified at the creation of the message queue.
308 * Not every message queue implementation supports an error handler.
310 * @param cls closure with the `struct GNUNET_NAMECACHE_Handle *`
311 * @param error error code
314 mq_error_handler (void *cls,
315 enum GNUNET_MQ_Error error)
317 struct GNUNET_NAMECACHE_Handle *h = cls;
324 * Reconnect to namecache service.
326 * @param h the handle to the NAMECACHE service
329 reconnect (struct GNUNET_NAMECACHE_Handle *h)
331 struct GNUNET_MQ_MessageHandler handlers[] = {
332 GNUNET_MQ_hd_var_size (lookup_block_response,
333 GNUNET_MESSAGE_TYPE_NAMECACHE_LOOKUP_BLOCK_RESPONSE,
334 struct LookupBlockResponseMessage,
336 GNUNET_MQ_hd_fixed_size (block_cache_response,
337 GNUNET_MESSAGE_TYPE_NAMECACHE_BLOCK_CACHE_RESPONSE,
338 struct BlockCacheResponseMessage,
340 GNUNET_MQ_handler_end ()
342 GNUNET_assert (NULL == h->mq);
343 h->mq = GNUNET_CLIENT_connect (h->cfg,
352 * Re-establish the connection to the service.
354 * @param cls handle to use to re-connect.
357 reconnect_task (void *cls)
359 struct GNUNET_NAMECACHE_Handle *h = cls;
361 h->reconnect_task = NULL;
367 * Disconnect from service and then reconnect.
369 * @param h our handle
372 force_reconnect (struct GNUNET_NAMECACHE_Handle *h)
374 struct GNUNET_NAMECACHE_QueueEntry *qe;
376 h->reconnect = GNUNET_NO;
377 GNUNET_MQ_destroy (h->mq);
379 while (NULL != (qe = h->op_head))
381 GNUNET_CONTAINER_DLL_remove (h->op_head,
384 if (NULL != qe->cont)
385 qe->cont (qe->cont_cls,
387 _("Error communicating with namecache service"));
390 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
391 "Reconnecting to namecache\n");
392 h->reconnect_delay = GNUNET_TIME_STD_BACKOFF (h->reconnect_delay);
393 h->reconnect_task = GNUNET_SCHEDULER_add_delayed (h->reconnect_delay,
400 * Get a fresh operation id to distinguish between namecache requests
402 * @param h the namecache handle
403 * @return next operation id to use
406 get_op_id (struct GNUNET_NAMECACHE_Handle *h)
408 return h->last_op_id_used++;
413 * Initialize the connection with the NAMECACHE service.
415 * @param cfg configuration to use
416 * @return handle to the GNS service, or NULL on error
418 struct GNUNET_NAMECACHE_Handle *
419 GNUNET_NAMECACHE_connect (const struct GNUNET_CONFIGURATION_Handle *cfg)
421 struct GNUNET_NAMECACHE_Handle *h;
423 h = GNUNET_new (struct GNUNET_NAMECACHE_Handle);
436 * Disconnect from the namecache service (and free associated
439 * @param h handle to the namecache
442 GNUNET_NAMECACHE_disconnect (struct GNUNET_NAMECACHE_Handle *h)
444 struct GNUNET_NAMECACHE_QueueEntry *q;
446 GNUNET_break (NULL == h->op_head);
447 while (NULL != (q = h->op_head))
449 GNUNET_CONTAINER_DLL_remove (h->op_head,
456 GNUNET_MQ_destroy (h->mq);
459 if (NULL != h->reconnect_task)
461 GNUNET_SCHEDULER_cancel (h->reconnect_task);
462 h->reconnect_task = NULL;
469 * Store an item in the namecache. If the item is already present,
470 * it is replaced with the new record.
472 * @param h handle to the namecache
473 * @param block block to store
474 * @param cont continuation to call when done
475 * @param cont_cls closure for @a cont
476 * @return handle to abort the request, NULL on error
478 struct GNUNET_NAMECACHE_QueueEntry *
479 GNUNET_NAMECACHE_block_cache (struct GNUNET_NAMECACHE_Handle *h,
480 const struct GNUNET_GNSRECORD_Block *block,
481 GNUNET_NAMECACHE_ContinuationWithStatus cont,
484 struct GNUNET_NAMECACHE_QueueEntry *qe;
485 struct BlockCacheMessage *msg;
486 struct GNUNET_MQ_Envelope *env;
492 blen = ntohl (block->purpose.size)
493 - sizeof (struct GNUNET_TIME_AbsoluteNBO)
494 - sizeof (struct GNUNET_CRYPTO_EccSignaturePurpose);
496 qe = GNUNET_new (struct GNUNET_NAMECACHE_QueueEntry);
499 qe->cont_cls = cont_cls;
501 GNUNET_CONTAINER_DLL_insert_tail (h->op_head,
505 env = GNUNET_MQ_msg_extra (msg,
507 GNUNET_MESSAGE_TYPE_NAMECACHE_BLOCK_CACHE);
508 msg->gns_header.r_id = htonl (rid);
509 msg->expire = block->expiration_time;
510 msg->signature = block->signature;
511 msg->derived_key = block->derived_key;
512 GNUNET_memcpy (&msg[1],
515 GNUNET_MQ_send (h->mq,
522 * Get a result for a particular key from the namecache. The processor
523 * will only be called once.
525 * @param h handle to the namecache
526 * @param derived_hash hash of zone key combined with name to lookup
527 * @param proc function to call on the matching block, or with
528 * NULL if there is no matching block
529 * @param proc_cls closure for @a proc
530 * @return a handle that can be used to cancel, NULL on error
532 struct GNUNET_NAMECACHE_QueueEntry *
533 GNUNET_NAMECACHE_lookup_block (struct GNUNET_NAMECACHE_Handle *h,
534 const struct GNUNET_HashCode *derived_hash,
535 GNUNET_NAMECACHE_BlockProcessor proc,
538 struct GNUNET_NAMECACHE_QueueEntry *qe;
539 struct LookupBlockMessage *msg;
540 struct GNUNET_MQ_Envelope *env;
545 LOG (GNUNET_ERROR_TYPE_DEBUG,
546 "Looking for block under %s\n",
547 GNUNET_h2s (derived_hash));
549 qe = GNUNET_new (struct GNUNET_NAMECACHE_QueueEntry);
551 qe->block_proc = proc;
552 qe->block_proc_cls = proc_cls;
554 GNUNET_CONTAINER_DLL_insert_tail (h->op_head,
557 env = GNUNET_MQ_msg (msg,
558 GNUNET_MESSAGE_TYPE_NAMECACHE_LOOKUP_BLOCK);
559 msg->gns_header.r_id = htonl (rid);
560 msg->query = *derived_hash;
561 GNUNET_MQ_send (h->mq,
568 * Cancel a namecache operation. The final callback from the
569 * operation must not have been done yet.
571 * @param qe operation to cancel
574 GNUNET_NAMECACHE_cancel (struct GNUNET_NAMECACHE_QueueEntry *qe)
576 struct GNUNET_NAMECACHE_Handle *h = qe->nsh;
578 GNUNET_CONTAINER_DLL_remove (h->op_head,
585 /* end of namecache_api.c */