2 This file is part of GNUnet.
3 (C) 2009, 2010 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.
23 * @brief library to access the DHT service
24 * @author Christian Grothoff
25 * @author Nathan Evans
27 * TODO: Only allow a single message until confirmed as received by
28 * the service. For put messages call continuation as soon as
29 * receipt acknowledged (then remove), for GET or other messages
30 * only call continuation when data received.
31 * Add unique identifier to message types requesting data to be
35 #include "gnunet_bandwidth_lib.h"
36 #include "gnunet_client_lib.h"
37 #include "gnunet_constants.h"
38 #include "gnunet_container_lib.h"
39 #include "gnunet_arm_service.h"
40 #include "gnunet_hello_lib.h"
41 #include "gnunet_protocols.h"
42 #include "gnunet_server_lib.h"
43 #include "gnunet_time_lib.h"
44 #include "gnunet_dht_service.h"
47 #define DEBUG_DHT_API GNUNET_YES
49 #define DEFAULT_DHT_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 5)
54 * Message that is pending
56 struct GNUNET_MessageHeader *msg;
59 * Timeout for this message
61 struct GNUNET_TIME_Relative timeout;
64 * Continuation to call on message send
65 * or message receipt confirmation
67 GNUNET_DHT_MessageCallback cont;
70 * Continuation closure
75 * Whether or not to await verification the message
76 * was received by the service
81 * Unique ID for this request
87 struct GNUNET_DHT_GetContext
92 * Iterator to call on data receipt
94 GNUNET_DHT_GetIterator iter;
97 * Closure for the iterator callback
104 * Handle to control a unique operation (one that is
105 * expected to return results)
107 struct GNUNET_DHT_RouteHandle
111 * Unique identifier for this request (for key collisions)
116 * Key that this get request is for
121 * Iterator to call on data receipt
123 GNUNET_DHT_ReplyProcessor iter;
126 * Closure for the iterator callback
131 * Main handle to this DHT api
133 struct GNUNET_DHT_Handle *dht_handle;
137 * Handle for a non unique request, holds callback
138 * which needs to be called before we allow other
139 * messages to be processed and sent to the DHT service
141 struct GNUNET_DHT_NonUniqueHandle
144 * Key that this get request is for
149 * Type of data get request was for
154 * Continuation to call on service
155 * confirmation of message receipt.
157 GNUNET_SCHEDULER_Task cont;
160 * Send continuation cls
167 * Connection to the DHT service.
169 struct GNUNET_DHT_Handle
174 struct GNUNET_SCHEDULER_Handle *sched;
177 * Configuration to use.
179 const struct GNUNET_CONFIGURATION_Handle *cfg;
182 * Socket (if available).
184 struct GNUNET_CLIENT_Connection *client;
187 * Currently pending transmission request.
189 struct GNUNET_CLIENT_TransmitHandle *th;
192 * Message we are currently sending, only allow
193 * a single message to be queued. If not unique
194 * (typically a put request), await a confirmation
195 * from the service that the message was received.
196 * If unique, just fire and forget.
198 struct PendingMessage *current;
201 * Hash map containing the current outstanding unique requests
203 struct GNUNET_CONTAINER_MultiHashMap *outstanding_requests;
206 * Non unique handle. If set don't schedule another non
209 struct GNUNET_DHT_NonUniqueHandle *non_unique_request;
212 * Kill off the connection and any pending messages.
218 static struct GNUNET_TIME_Relative default_request_timeout;
220 /* Forward declaration */
221 static void process_pending_message(struct GNUNET_DHT_Handle *handle);
223 static GNUNET_HashCode * hash_from_uid(uint64_t uid)
227 GNUNET_HashCode *hash;
228 hash = GNUNET_malloc(sizeof(GNUNET_HashCode));
231 while (count < sizeof(GNUNET_HashCode))
233 remaining = sizeof(GNUNET_HashCode) - count;
234 if (remaining > sizeof(uid))
235 remaining = sizeof(uid);
237 memcpy(hash, &uid, remaining);
245 * Handler for messages received from the DHT service
246 * a demultiplexer which handles numerous message types
249 void service_message_handler (void *cls,
250 const struct GNUNET_MessageHeader *msg)
252 struct GNUNET_DHT_Handle *handle = cls;
253 struct GNUNET_DHT_Message *dht_msg = (struct GNUNET_DHT_Message *)msg;
254 struct GNUNET_MessageHeader *enc_msg;
255 struct GNUNET_DHT_RouteHandle *route_handle;
256 GNUNET_HashCode *uid_hash;
258 /* TODO: find out message type, handle callbacks for different types of messages.
259 * Should be a non unique acknowledgment, or unique result. */
262 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
263 "`%s': Received response to message (uid %llu)\n", "DHT API", ntohl(dht_msg->unique_id));
266 if (ntohs(dht_msg->unique))
268 uid_hash = hash_from_uid(ntohl(dht_msg->unique_id));
270 route_handle = GNUNET_CONTAINER_multihashmap_get(handle->outstanding_requests, uid_hash);
271 if (route_handle == NULL) /* We have no recollection of this request */
274 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
275 "`%s': Received response to message (uid %llu), but have no recollection of it!\n", "DHT API", ntohl(dht_msg->unique_id));
280 enc_size = ntohs(dht_msg->header.size) - sizeof(struct GNUNET_DHT_Message);
281 GNUNET_assert(enc_size > 0);
282 enc_msg = (struct GNUNET_MessageHeader *)&dht_msg[1];
283 route_handle->iter(route_handle->iter_cls, enc_msg);
288 if (handle->current->unique_id == ntohl(dht_msg->unique_id))
290 handle->current->cont(handle->current->cont_cls, GNUNET_OK);
291 GNUNET_free(handle->current->msg);
292 handle->current = NULL;
293 GNUNET_free(handle->current);
302 * Initialize the connection with the DHT service.
304 * @param cfg configuration to use
305 * @param sched scheduler to use
306 * @param ht_len size of the internal hash table to use for
307 * processing multiple GET/FIND requests in parallel
308 * @return NULL on error
310 struct GNUNET_DHT_Handle *
311 GNUNET_DHT_connect (struct GNUNET_SCHEDULER_Handle *sched,
312 const struct GNUNET_CONFIGURATION_Handle *cfg,
315 struct GNUNET_DHT_Handle *handle;
317 handle = GNUNET_malloc(sizeof(struct GNUNET_DHT_Handle));
319 default_request_timeout = GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_SECONDS, 5);
321 handle->sched = sched;
323 handle->current = NULL;
324 handle->do_destroy = GNUNET_NO;
327 handle->client = GNUNET_CLIENT_connect(sched, "dht", cfg);
328 handle->outstanding_requests = GNUNET_CONTAINER_multihashmap_create(ht_len);
330 if (handle->client == NULL)
333 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
334 "`%s': Connection to service in progress\n", "DHT API");
336 GNUNET_CLIENT_receive (handle->client,
337 &service_message_handler,
338 handle, GNUNET_TIME_UNIT_FOREVER_REL);
345 * Shutdown connection with the DHT service.
347 * @param h connection to shut down
350 GNUNET_DHT_disconnect (struct GNUNET_DHT_Handle *handle)
353 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
354 "`%s': Called GNUNET_DHT_disconnect\n", "DHT API");
356 GNUNET_assert(handle != NULL);
358 if (handle->th != NULL) /* We have a live transmit request in the Aether */
360 GNUNET_CLIENT_notify_transmit_ready_cancel (handle->th);
363 if (handle->current != NULL) /* We are trying to send something now, clean it up */
364 GNUNET_free(handle->current);
366 if (handle->client != NULL) /* Finally, disconnect from the service */
368 GNUNET_CLIENT_disconnect (handle->client, GNUNET_NO);
369 handle->client = NULL;
372 GNUNET_free (handle);
377 * Send complete (or failed), schedule next (or don't)
380 finish (struct GNUNET_DHT_Handle *handle, int code)
382 /* TODO: if code is not GNUNET_OK, do something! */
383 struct PendingMessage *pos = handle->current;
385 GNUNET_assert(pos != NULL);
389 if (pos->cont != NULL)
390 pos->cont(pos->cont_cls, code);
392 GNUNET_free(pos->msg);
393 handle->current = NULL;
396 /* Otherwise we need to wait for a response to this message! */
400 * Transmit the next pending message, called by notify_transmit_ready
403 transmit_pending (void *cls, size_t size, void *buf)
405 struct GNUNET_DHT_Handle *handle = cls;
411 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
412 "`%s': In transmit_pending buf is NULL\n", "DHT API");
414 /* FIXME: free associated resources or summat */
415 finish(handle, GNUNET_SYSERR);
421 if (handle->current != NULL)
423 tsize = ntohs(handle->current->msg->size);
427 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
428 "`%s': Sending message size %d\n", "DHT API", tsize);
430 memcpy(buf, handle->current->msg, tsize);
438 /* Have no pending request */
444 * Try to (re)connect to the dht service.
446 * @return GNUNET_YES on success, GNUNET_NO on failure.
449 try_connect (struct GNUNET_DHT_Handle *ret)
451 if (ret->client != NULL)
453 ret->client = GNUNET_CLIENT_connect (ret->sched, "dht", ret->cfg);
454 if (ret->client != NULL)
457 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
458 _("Failed to connect to the dht service!\n"));
465 * Try to send messages from list of messages to send
467 static void process_pending_message(struct GNUNET_DHT_Handle *handle)
470 if (handle->current != NULL)
471 return; /* action already pending */
472 if (GNUNET_YES != try_connect (handle))
474 finish (handle, GNUNET_SYSERR);
478 /* TODO: set do_destroy somewhere's, see what needs to happen in that case! */
479 if (handle->do_destroy)
481 //GNUNET_DHT_disconnect (handle); /* FIXME: replace with proper disconnect stuffs */
486 (handle->th = GNUNET_CLIENT_notify_transmit_ready (handle->client,
487 ntohs(handle->current->msg->size),
488 handle->current->timeout,
490 &transmit_pending, handle)))
493 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
494 "Failed to transmit request to dht service.\n");
496 finish (handle, GNUNET_SYSERR);
499 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
500 "`%s': Scheduled sending message of size %d to service\n", "DHT API", ntohs(handle->current->msg->size));
505 * Iterator called on each result obtained from a generic route
508 void get_reply_iterator (void *cls,
509 const struct GNUNET_MessageHeader *reply)
515 * Perform an asynchronous FIND_PEER operation on the DHT.
517 * @param handle handle to the DHT service
518 * @param key the key to look up
519 * @param desired_replication_level how many peers should ultimately receive
520 * this message (advisory only, target may be too high for the
521 * given DHT or not hit exactly).
522 * @param options options for routing
523 * @param enc send the encapsulated message to a peer close to the key
524 * @param iter function to call on each result, NULL if no replies are expected
525 * @param iter_cls closure for iter
526 * @param timeout when to abort with an error if we fail to get
527 * a confirmation for the PUT from the local DHT service
528 * @param cont continuation to call when done;
529 * reason will be TIMEOUT on error,
530 * reason will be PREREQ_DONE on success
531 * @param cont_cls closure for cont
532 * @return handle to stop the request
534 struct GNUNET_DHT_RouteHandle *
535 GNUNET_DHT_route_start (struct GNUNET_DHT_Handle *handle,
536 const GNUNET_HashCode *key,
537 unsigned int desired_replication_level,
538 enum GNUNET_DHT_RouteOption options,
539 const struct GNUNET_MessageHeader *enc,
540 struct GNUNET_TIME_Relative timeout,
541 GNUNET_DHT_ReplyProcessor iter,
543 GNUNET_DHT_MessageCallback cont,
546 struct GNUNET_DHT_RouteHandle *route_handle;
547 struct PendingMessage *pending;
548 struct GNUNET_DHT_Message *message;
551 GNUNET_HashCode *uid_key;
554 is_unique = GNUNET_YES;
556 is_unique = GNUNET_NO;
562 route_handle = GNUNET_malloc(sizeof(struct GNUNET_DHT_RouteHandle));
563 memcpy(&route_handle->key, key, sizeof(GNUNET_HashCode));
564 route_handle->iter = iter;
565 route_handle->iter_cls = iter_cls;
566 route_handle->dht_handle = handle;
567 route_handle->uid = GNUNET_CRYPTO_random_u64(GNUNET_CRYPTO_QUALITY_WEAK, -1);
570 uid_key = hash_from_uid(route_handle->uid);
571 /* While we have an outstanding request with the same identifier! */
572 while (GNUNET_CONTAINER_multihashmap_contains(handle->outstanding_requests, uid_key) == GNUNET_YES)
574 GNUNET_free(uid_key);
575 uid_key = hash_from_uid(route_handle->uid);
578 * Store based on random identifier!
580 GNUNET_CONTAINER_multihashmap_put(handle->outstanding_requests, uid_key, route_handle, GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE);
581 msize = sizeof(struct GNUNET_DHT_Message) + ntohs(enc->size) + sizeof(route_handle->uid);
582 GNUNET_free(uid_key);
586 msize = sizeof(struct GNUNET_DHT_Message) + ntohs(enc->size);
589 message = GNUNET_malloc(msize);
590 message->header.size = htons(msize);
591 message->header.type = htons(GNUNET_MESSAGE_TYPE_DHT);
592 memcpy(&message->key, key, sizeof(GNUNET_HashCode));
593 message->options = htons(options);
594 message->desired_replication_level = htons(options);
595 message->unique = htons(is_unique);
597 pending = GNUNET_malloc(sizeof(struct PendingMessage));
598 pending->msg = &message->header;
599 pending->timeout = timeout;
600 pending->cont = cont;
601 pending->cont_cls = cont_cls;
602 pending->is_unique = is_unique;
604 GNUNET_assert(handle->current == NULL);
606 process_pending_message(handle);
612 GNUNET_DHT_route_stop (struct GNUNET_DHT_RouteHandle *fph);
615 void dht_get_processor (void *cls,
616 const struct GNUNET_MessageHeader *reply)
622 * Perform an asynchronous GET operation on the DHT identified.
624 * @param h handle to the DHT service
625 * @param type expected type of the response object
626 * @param key the key to look up
627 * @param iter function to call on each result
628 * @param iter_cls closure for iter
629 * @return handle to stop the async get
631 struct GNUNET_DHT_RouteHandle *
632 GNUNET_DHT_get_start (struct GNUNET_DHT_Handle *handle,
633 struct GNUNET_TIME_Relative timeout,
635 const GNUNET_HashCode * key,
636 GNUNET_DHT_GetIterator iter,
639 struct GNUNET_DHT_GetContext *get_context;
640 struct GNUNET_DHT_GetMessage *get_msg;
642 if (handle->current != NULL) /* Can't send right now, we have a pending message... */
645 get_context = GNUNET_malloc(sizeof(struct GNUNET_DHT_GetContext));
646 get_context->iter = iter;
647 get_context->iter_cls = iter_cls;
650 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
651 "`%s': Inserting pending get request with key %s\n", "DHT API", GNUNET_h2s(key));
654 get_msg = GNUNET_malloc(sizeof(struct GNUNET_DHT_GetMessage));
655 get_msg->header.type = htons(GNUNET_MESSAGE_TYPE_DHT_GET);
656 get_msg->header.size = htons(sizeof(struct GNUNET_DHT_GetMessage));
657 get_msg->type = htonl(type);
659 return GNUNET_DHT_route_start(handle, key, 0, 0, &get_msg->header, timeout, &get_reply_iterator, get_context, NULL, NULL);
665 GNUNET_DHT_route_stop (struct GNUNET_DHT_RouteHandle *route_handle)
667 struct PendingMessage *pending;
668 struct GNUNET_DHT_StopMessage *message;
670 GNUNET_HashCode *uid_key;
672 msize = sizeof(struct GNUNET_DHT_StopMessage);
674 message = GNUNET_malloc(msize);
675 message->header.size = htons(msize);
676 message->header.type = htons(GNUNET_MESSAGE_TYPE_DHT_STOP);
677 message->unique_id = htonl(route_handle->uid);
679 pending = GNUNET_malloc(sizeof(struct PendingMessage));
680 pending->msg = (struct GNUNET_MessageHeader *)message;
681 pending->timeout = DEFAULT_DHT_TIMEOUT;
682 pending->cont = NULL;
683 pending->cont_cls = NULL;
684 pending->is_unique = GNUNET_NO;
686 GNUNET_assert(route_handle->dht_handle->current == NULL);
688 process_pending_message(route_handle->dht_handle);
690 uid_key = hash_from_uid(route_handle->uid);
692 if (GNUNET_CONTAINER_multihashmap_remove(route_handle->dht_handle->outstanding_requests, uid_key, route_handle) != GNUNET_YES)
695 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
696 "`%s': Remove outstanding request from hashmap failed for key %s, uid %llu\n", "DHT API", GNUNET_h2s(uid_key), route_handle->uid);
705 * Stop async DHT-get. Frees associated resources.
707 * @param record GET operation to stop.
710 GNUNET_DHT_get_stop (struct GNUNET_DHT_RouteHandle *handle)
713 struct GNUNET_DHT_GetMessage *get_msg;
714 struct GNUNET_DHT_Handle *handle;
715 GNUNET_HashCode *uid_key;
718 GNUNET_DHT_route_stop(handle);
721 uid_key = hash_from_uid(get_handle->uid);
722 GNUNET_assert(GNUNET_CONTAINER_multihashmap_remove(handle->outstanding_requests, uid_key, get_handle) == GNUNET_YES);
724 if (handle->do_destroy == GNUNET_NO)
726 get_msg = GNUNET_malloc(sizeof(struct GNUNET_DHT_GetMessage));
727 get_msg->header.type = htons(GNUNET_MESSAGE_TYPE_DHT_GET_STOP);
728 get_msg->header.size = htons(sizeof(struct GNUNET_DHT_GetMessage));
734 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
735 "`%s': Removing pending get request with key %s, uid %llu\n", "DHT API", GNUNET_h2s(&handle->key), handle->uid);
741 * Perform a PUT operation storing data in the DHT.
743 * @param h handle to DHT service
744 * @param key the key to store under
745 * @param type type of the value
746 * @param size number of bytes in data; must be less than 64k
747 * @param data the data to store
748 * @param exp desired expiration time for the value
749 * @param cont continuation to call when done;
750 * reason will be TIMEOUT on error,
751 * reason will be PREREQ_DONE on success
752 * @param cont_cls closure for cont
754 * @return GNUNET_YES if put message is queued for transmission
757 GNUNET_DHT_put (struct GNUNET_DHT_Handle *handle,
758 const GNUNET_HashCode * key,
762 struct GNUNET_TIME_Absolute exp,
763 struct GNUNET_TIME_Relative timeout,
764 GNUNET_DHT_MessageCallback cont,
767 struct GNUNET_DHT_PutMessage *put_msg;
770 if (handle->current != NULL)
772 cont(cont_cls, GNUNET_SYSERR);
777 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
778 "`%s': Inserting pending put request with key %s\n", "DHT API", GNUNET_h2s(key));
781 msize = sizeof(struct GNUNET_DHT_PutMessage) + size;
782 put_msg = GNUNET_malloc(msize);
783 put_msg->header.type = htons(GNUNET_MESSAGE_TYPE_DHT_PUT);
784 put_msg->header.size = htons(msize);
785 put_msg->type = htonl(type);
786 memcpy(&put_msg[1], data, size);
788 GNUNET_DHT_route_start(handle, key, 0, 0, &put_msg->header, timeout, NULL, NULL, cont, cont_cls);