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22 * @file peerinfo/peerinfo_api.c
23 * @brief API to access peerinfo service
24 * @author Christian Grothoff
27 #include "gnunet_client_lib.h"
28 #include "gnunet_container_lib.h"
29 #include "gnunet_peerinfo_service.h"
30 #include "gnunet_protocols.h"
31 #include "gnunet_time_lib.h"
35 * Function to call after transmission has succeeded.
38 * @param success GNUNET_OK if transmission worked, GNUNET_SYSERR on error
40 typedef void (*TransmissionContinuation) (void *cls, int success);
44 * Entry in the transmission queue to PEERINFO service.
46 struct TransmissionQueueEntry
49 * This is a linked list.
51 struct TransmissionQueueEntry *next;
54 * This is a linked list.
56 struct TransmissionQueueEntry *prev;
59 * Function to call after request has been transmitted, or NULL (in which
60 * case we must consider sending the next entry immediately).
62 TransmissionContinuation cont;
70 * Timeout for the operation.
72 struct GNUNET_TIME_Absolute timeout;
75 * Number of bytes of the request message (follows after this struct).
83 * Handle to the peerinfo service.
85 struct GNUNET_PEERINFO_Handle
90 const struct GNUNET_CONFIGURATION_Handle *cfg;
93 * Connection to the service.
95 struct GNUNET_CLIENT_Connection *client;
98 * Head of transmission queue.
100 struct TransmissionQueueEntry *tq_head;
103 * Tail of transmission queue.
105 struct TransmissionQueueEntry *tq_tail;
108 * Handle for the current transmission request, or NULL if none is pending.
110 struct GNUNET_CLIENT_TransmitHandle *th;
113 * ID for a reconnect task.
115 GNUNET_SCHEDULER_TaskIdentifier r_task;
118 * Set to GNUNET_YES if we are currently receiving replies from the
127 * Connect to the peerinfo service.
129 * @param cfg configuration to use
130 * @return NULL on error (configuration related, actual connection
131 * establishment may happen asynchronously).
133 struct GNUNET_PEERINFO_Handle *
134 GNUNET_PEERINFO_connect (const struct GNUNET_CONFIGURATION_Handle *cfg)
136 struct GNUNET_PEERINFO_Handle *ret;
138 ret = GNUNET_malloc (sizeof (struct GNUNET_PEERINFO_Handle));
139 ret->client = GNUNET_CLIENT_connect ("peerinfo", cfg);
146 * Disconnect from the peerinfo service. Note that all iterators must
147 * have completed or have been cancelled by the time this function is
148 * called (otherwise, calling this function is a serious error).
149 * Furthermore, if 'GNUNET_PEERINFO_add_peer' operations are still
150 * pending, they will be cancelled silently on disconnect.
152 * @param h handle to disconnect
155 GNUNET_PEERINFO_disconnect (struct GNUNET_PEERINFO_Handle *h)
157 struct TransmissionQueueEntry *tqe;
159 while (NULL != (tqe = h->tq_head))
161 GNUNET_CONTAINER_DLL_remove (h->tq_head, h->tq_tail, tqe);
162 if (tqe->cont != NULL)
163 tqe->cont (tqe->cont_cls, GNUNET_SYSERR);
168 GNUNET_CLIENT_notify_transmit_ready_cancel (h->th);
171 if (NULL != h->client)
173 GNUNET_CLIENT_disconnect (h->client, GNUNET_NO);
176 if (GNUNET_SCHEDULER_NO_TASK != h->r_task)
178 GNUNET_SCHEDULER_cancel (h->r_task);
179 h->r_task = GNUNET_SCHEDULER_NO_TASK;
186 * Check if we have a request pending in the transmission queue and are
187 * able to transmit it right now. If so, schedule transmission.
189 * @param h handle to the service
192 trigger_transmit (struct GNUNET_PEERINFO_Handle *h);
196 * Close the existing connection to PEERINFO and reconnect.
198 * @param h handle to the service
201 reconnect (struct GNUNET_PEERINFO_Handle *h);
204 * Task scheduled to re-try connecting to the peerinfo service.
206 * @param cls the 'struct GNUNET_PEERINFO_Handle'
207 * @param tc scheduler context
210 reconnect_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
212 struct GNUNET_PEERINFO_Handle *h = cls;
214 h->r_task = GNUNET_SCHEDULER_NO_TASK;
220 * Close the existing connection to PEERINFO and reconnect.
222 * @param h handle to the service
225 reconnect (struct GNUNET_PEERINFO_Handle *h)
227 if (h->r_task != GNUNET_SCHEDULER_NO_TASK)
229 GNUNET_SCHEDULER_cancel (h->r_task);
230 h->r_task = GNUNET_SCHEDULER_NO_TASK;
234 GNUNET_CLIENT_notify_transmit_ready_cancel (h->th);
237 if (NULL != h->client)
239 GNUNET_CLIENT_disconnect (h->client, GNUNET_SYSERR);
242 h->client = GNUNET_CLIENT_connect ("peerinfo", h->cfg);
243 if (NULL == h->client)
246 GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_SECONDS, &reconnect_task,
250 trigger_transmit (h);
255 * Transmit the request at the head of the transmission queue
256 * and trigger continuation (if any).
258 * @param cls the 'struct GNUNET_PEERINFO_Handle' (with the queue)
259 * @param size size of the buffer (0 on error)
260 * @param buf where to copy the message
261 * @return number of bytes copied to buf
264 do_transmit (void *cls, size_t size, void *buf)
266 struct GNUNET_PEERINFO_Handle *h = cls;
267 struct TransmissionQueueEntry *tqe = h->tq_head;
275 GNUNET_log (GNUNET_ERROR_TYPE_WARNING | GNUNET_ERROR_TYPE_BULK,
276 _("Failed to transmit message to `%s' service.\n"), "PEERINFO");
277 GNUNET_CONTAINER_DLL_remove (h->tq_head, h->tq_tail, tqe);
279 if (tqe->cont != NULL)
280 tqe->cont (tqe->cont_cls, GNUNET_SYSERR);
285 GNUNET_assert (size >= ret);
286 memcpy (buf, &tqe[1], ret);
288 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
289 "Transmitting request of size %u to `%s' service.\n", ret,
292 GNUNET_CONTAINER_DLL_remove (h->tq_head, h->tq_tail, tqe);
293 if (tqe->cont != NULL)
294 tqe->cont (tqe->cont_cls, GNUNET_OK);
296 trigger_transmit (h);
303 * Check if we have a request pending in the transmission queue and are
304 * able to transmit it right now. If so, schedule transmission.
306 * @param h handle to the service
309 trigger_transmit (struct GNUNET_PEERINFO_Handle *h)
311 struct TransmissionQueueEntry *tqe;
313 if (NULL == (tqe = h->tq_head))
317 if (h->in_receive == GNUNET_YES)
319 if (NULL == h->client)
325 GNUNET_CLIENT_notify_transmit_ready (h->client, tqe->size,
326 GNUNET_TIME_absolute_get_remaining
327 (tqe->timeout), GNUNET_YES,
333 * Add a host to the persistent list. This method operates in
334 * semi-reliable mode: if the transmission is not completed by
335 * the time 'GNUNET_PEERINFO_disconnect' is called, it will be
336 * aborted. Furthermore, if a second HELLO is added for the
337 * same peer before the first one was transmitted, PEERINFO may
338 * merge the two HELLOs prior to transmission to the service.
340 * @param h handle to the peerinfo service
341 * @param hello the verified (!) HELLO message
344 GNUNET_PEERINFO_add_peer (struct GNUNET_PEERINFO_Handle *h,
345 const struct GNUNET_HELLO_Message *hello)
347 uint16_t hs = GNUNET_HELLO_size (hello);
348 struct TransmissionQueueEntry *tqe;
351 struct GNUNET_PeerIdentity peer;
353 GNUNET_assert (GNUNET_OK == GNUNET_HELLO_get_id (hello, &peer));
354 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
355 "Adding peer `%s' to PEERINFO database (%u bytes of `%s')\n",
356 GNUNET_i2s (&peer), hs, "HELLO");
358 tqe = GNUNET_malloc (sizeof (struct TransmissionQueueEntry) + hs);
360 tqe->timeout = GNUNET_TIME_UNIT_FOREVER_ABS;
361 memcpy (&tqe[1], hello, hs);
362 GNUNET_CONTAINER_DLL_insert_after (h->tq_head, h->tq_tail, h->tq_tail, tqe);
363 trigger_transmit (h);
368 * Context for an iteration request.
370 struct GNUNET_PEERINFO_IteratorContext
373 * Handle to the PEERINFO service.
375 struct GNUNET_PEERINFO_Handle *h;
378 * Function to call with the results.
380 GNUNET_PEERINFO_Processor callback;
383 * Closure for 'callback'.
388 * Our entry in the transmission queue.
390 struct TransmissionQueueEntry *tqe;
393 * Task responsible for timeout.
395 GNUNET_SCHEDULER_TaskIdentifier timeout_task;
398 * Timeout for the operation.
400 struct GNUNET_TIME_Absolute timeout;
403 * Are we now receiving?
410 * Type of a function to call when we receive a message
414 * @param msg message received, NULL on timeout or fatal error
417 peerinfo_handler (void *cls, const struct GNUNET_MessageHeader *msg)
419 struct GNUNET_PEERINFO_IteratorContext *ic = cls;
420 const struct InfoMessage *im;
421 const struct GNUNET_HELLO_Message *hello;
424 ic->h->in_receive = GNUNET_NO;
428 if (ic->timeout_task != GNUNET_SCHEDULER_NO_TASK)
429 GNUNET_SCHEDULER_cancel (ic->timeout_task);
430 if (ic->callback != NULL)
431 ic->callback (ic->callback_cls, NULL, NULL,
432 _("Failed to receive response from `PEERINFO' service."));
436 if (ntohs (msg->type) == GNUNET_MESSAGE_TYPE_PEERINFO_INFO_END)
439 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
440 "Received end of list of peers from `%s' service\n",
443 trigger_transmit (ic->h);
444 if (ic->timeout_task != GNUNET_SCHEDULER_NO_TASK)
445 GNUNET_SCHEDULER_cancel (ic->timeout_task);
446 if (ic->callback != NULL)
447 ic->callback (ic->callback_cls, NULL, NULL, NULL);
451 ms = ntohs (msg->size);
452 if ((ms < sizeof (struct InfoMessage)) ||
453 (ntohs (msg->type) != GNUNET_MESSAGE_TYPE_PEERINFO_INFO))
457 if (ic->timeout_task != GNUNET_SCHEDULER_NO_TASK)
458 GNUNET_SCHEDULER_cancel (ic->timeout_task);
459 if (ic->callback != NULL)
460 ic->callback (ic->callback_cls, NULL, NULL,
461 _("Received invalid message from `PEERINFO' service.\n"));
465 im = (const struct InfoMessage *) msg;
466 GNUNET_break (0 == ntohl (im->reserved));
468 if (ms > sizeof (struct InfoMessage) + sizeof (struct GNUNET_MessageHeader))
470 hello = (const struct GNUNET_HELLO_Message *) &im[1];
471 if (ms != sizeof (struct InfoMessage) + GNUNET_HELLO_size (hello))
475 if (ic->timeout_task != GNUNET_SCHEDULER_NO_TASK)
476 GNUNET_SCHEDULER_cancel (ic->timeout_task);
477 if (ic->callback != NULL)
478 ic->callback (ic->callback_cls, NULL, NULL,
479 _("Received invalid message from `PEERINFO' service.\n"));
485 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
486 "Received %u bytes of `%s' information about peer `%s' from `%s' service\n",
487 (hello == NULL) ? 0 : (unsigned int) GNUNET_HELLO_size (hello),
488 "HELLO", GNUNET_i2s (&im->peer), "PEERINFO");
490 ic->h->in_receive = GNUNET_YES;
491 if (ic->callback != NULL)
492 ic->callback (ic->callback_cls, &im->peer, hello, NULL);
493 GNUNET_CLIENT_receive (ic->h->client, &peerinfo_handler, ic,
494 GNUNET_TIME_absolute_get_remaining (ic->timeout));
499 * We've transmitted the iteration request. Now get ready to process
500 * the results (or handle transmission error).
502 * @param cls the 'struct GNUNET_PEERINFO_IteratorContext'
503 * @param transmit_success GNUNET_OK if transmission worked
506 iterator_start_receive (void *cls, int transmit_success)
508 struct GNUNET_PEERINFO_IteratorContext *ic = cls;
510 if (GNUNET_OK != transmit_success)
512 if (ic->timeout_task != GNUNET_SCHEDULER_NO_TASK)
514 GNUNET_SCHEDULER_cancel (ic->timeout_task);
515 ic->timeout_task = GNUNET_SCHEDULER_NO_TASK;
518 if (ic->callback != NULL)
519 ic->callback (ic->callback_cls, NULL, NULL,
521 ("Failed to transmit iteration request to `PEERINFO' service\n"));
526 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
527 "Waiting for response from `%s' service.\n", "PEERINFO");
529 ic->h->in_receive = GNUNET_YES;
530 ic->in_receive = GNUNET_YES;
532 GNUNET_CLIENT_receive (ic->h->client, &peerinfo_handler, ic,
533 GNUNET_TIME_absolute_get_remaining (ic->timeout));
538 * Peerinfo iteration request has timed out.
540 * @param cls the 'struct GNUNET_PEERINFO_IteratorContext*'
541 * @param tc scheduler context
544 signal_timeout (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
546 struct GNUNET_PEERINFO_IteratorContext *ic = cls;
548 ic->timeout_task = GNUNET_SCHEDULER_NO_TASK;
550 GNUNET_CONTAINER_DLL_remove (ic->h->tq_head, ic->h->tq_tail, ic->tqe);
553 ic->callback (ic->callback_cls, NULL, NULL,
555 ("Timeout transmitting iteration request to `PEERINFO' service.\n"));
557 GNUNET_free_non_null (ic->tqe);
563 * Call a method for each known matching host and change its trust
564 * value. The callback method will be invoked once for each matching
565 * host and then finally once with a NULL pointer. After that final
566 * invocation, the iterator context must no longer be used.
568 * Instead of calling this function with 'peer == NULL' it is often
569 * better to use 'GNUNET_PEERINFO_notify'.
571 * @param h handle to the peerinfo service
572 * @param peer restrict iteration to this peer only (can be NULL)
573 * @param timeout how long to wait until timing out
574 * @param callback the method to call for each peer
575 * @param callback_cls closure for callback
576 * @return iterator context
578 struct GNUNET_PEERINFO_IteratorContext *
579 GNUNET_PEERINFO_iterate (struct GNUNET_PEERINFO_Handle *h,
580 const struct GNUNET_PeerIdentity *peer,
581 struct GNUNET_TIME_Relative timeout,
582 GNUNET_PEERINFO_Processor callback, void *callback_cls)
584 struct GNUNET_MessageHeader *lapm;
585 struct ListPeerMessage *lpm;
586 struct GNUNET_PEERINFO_IteratorContext *ic;
587 struct TransmissionQueueEntry *tqe;
592 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
593 "Requesting list of peers from PEERINFO service\n");
596 GNUNET_malloc (sizeof (struct TransmissionQueueEntry) +
597 sizeof (struct GNUNET_MessageHeader));
598 tqe->size = sizeof (struct GNUNET_MessageHeader);
599 lapm = (struct GNUNET_MessageHeader *) &tqe[1];
600 lapm->size = htons (sizeof (struct GNUNET_MessageHeader));
601 lapm->type = htons (GNUNET_MESSAGE_TYPE_PEERINFO_GET_ALL);
606 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
607 "Requesting information on peer `%4s' from PEERINFO service\n",
611 GNUNET_malloc (sizeof (struct TransmissionQueueEntry) +
612 sizeof (struct ListPeerMessage));
613 tqe->size = sizeof (struct ListPeerMessage);
614 lpm = (struct ListPeerMessage *) &tqe[1];
615 lpm->header.size = htons (sizeof (struct ListPeerMessage));
616 lpm->header.type = htons (GNUNET_MESSAGE_TYPE_PEERINFO_GET);
617 memcpy (&lpm->peer, peer, sizeof (struct GNUNET_PeerIdentity));
619 ic = GNUNET_malloc (sizeof (struct GNUNET_PEERINFO_IteratorContext));
622 ic->callback = callback;
623 ic->callback_cls = callback_cls;
624 ic->timeout = GNUNET_TIME_relative_to_absolute (timeout);
626 GNUNET_SCHEDULER_add_delayed (timeout, &signal_timeout, ic);
627 tqe->timeout = ic->timeout;
628 tqe->cont = &iterator_start_receive;
630 tqe->timeout = ic->timeout;
631 GNUNET_CONTAINER_DLL_insert_after (h->tq_head, h->tq_tail, h->tq_tail, tqe);
632 trigger_transmit (h);
638 * Cancel an iteration over peer information.
640 * @param ic context of the iterator to cancel
643 GNUNET_PEERINFO_iterate_cancel (struct GNUNET_PEERINFO_IteratorContext *ic)
645 if (ic->timeout_task != GNUNET_SCHEDULER_NO_TASK)
647 GNUNET_SCHEDULER_cancel (ic->timeout_task);
648 ic->timeout_task = GNUNET_SCHEDULER_NO_TASK;
651 if (GNUNET_YES == ic->in_receive)
652 return; /* need to finish processing */
653 GNUNET_CONTAINER_DLL_remove (ic->h->tq_head, ic->h->tq_tail, ic->tqe);
654 GNUNET_free (ic->tqe);
659 /* end of peerinfo_api.c */