2 This file is part of GNUnet.
3 (C) 2001, 2002, 2006, 2008, 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.
23 * @brief code for access to services
24 * @author Christian Grothoff
26 * Generic TCP code for reliable, record-oriented TCP
27 * connections between clients and service providers.
31 #include "gnunet_common.h"
32 #include "gnunet_client_lib.h"
33 #include "gnunet_protocols.h"
34 #include "gnunet_server_lib.h"
35 #include "gnunet_scheduler_lib.h"
37 #define DEBUG_CLIENT GNUNET_NO
40 * How often do we re-try tranmsitting requests before giving up?
41 * Note that if we succeeded transmitting a request but failed to read
42 * a response, we do NOT re-try.
44 #define MAX_ATTEMPTS 50
46 #define UNIXPATH_RETRIES 0
50 * Handle for a transmission request.
52 struct GNUNET_CLIENT_TransmitHandle
57 struct GNUNET_CLIENT_Connection *sock;
60 * Function to call to get the data for transmission.
62 GNUNET_CONNECTION_TransmitReadyNotify notify;
70 * Handle to the transmission with the underlying
73 struct GNUNET_CONNECTION_TransmitHandle *th;
76 * If we are re-trying and are delaying to do so,
77 * handle to the scheduled task managing the delay.
79 GNUNET_SCHEDULER_TaskIdentifier reconnect_task;
82 * Timeout for the operation overall.
84 struct GNUNET_TIME_Absolute timeout;
87 * Number of bytes requested.
92 * Are we allowed to re-try to connect without telling
93 * the user (of this API) about the connection troubles?
98 * Number of attempts left for transmitting the request. We may
99 * fail the first time (say because the service is not yet up), in
100 * which case (if auto_retry is set) we wait a bit and re-try
101 * (timeout permitting).
103 unsigned int attempts_left;
109 * Context for processing
110 * "GNUNET_CLIENT_transmit_and_get_response" requests.
112 struct TransmitGetResponseContext
117 struct GNUNET_CLIENT_Connection *sock;
120 * Message to transmit; do not free, allocated
121 * right after this struct.
123 const struct GNUNET_MessageHeader *hdr;
128 struct GNUNET_TIME_Absolute timeout;
131 * Function to call when done.
133 GNUNET_CLIENT_MessageHandler rn;
142 * Struct to refer to a GNUnet TCP connection.
143 * This is more than just a socket because if the server
144 * drops the connection, the client automatically tries
145 * to reconnect (and for that needs connection information).
147 struct GNUNET_CLIENT_Connection
151 * the socket handle, NULL if not live
153 struct GNUNET_CONNECTION_Handle *sock;
157 * FIXME: why do we DUP the configuration? Avoid this!
159 struct GNUNET_CONFIGURATION_Handle *cfg;
162 * Name of the service we interact with.
167 * Context of a transmit_and_get_response operation, NULL
168 * if no such operation is pending.
170 struct TransmitGetResponseContext *tag;
173 * Handler for current receiver task.
175 GNUNET_CLIENT_MessageHandler receiver_handler;
178 * Closure for receiver_handler.
180 void *receiver_handler_cls;
183 * Handle for a pending transmission request, NULL if there is
186 struct GNUNET_CLIENT_TransmitHandle *th;
189 * Handler for service test completion (NULL unless in service_test)
191 GNUNET_SCHEDULER_Task test_cb;
194 * Deadline for calling 'test_cb'.
196 struct GNUNET_TIME_Absolute test_deadline;
199 * If we are re-trying and are delaying to do so,
200 * handle to the scheduled task managing the delay.
202 GNUNET_SCHEDULER_TaskIdentifier receive_task;
205 * Closure for test_cb (NULL unless in service_test)
210 * Buffer for received message.
215 * Timeout for receiving a response (absolute time).
217 struct GNUNET_TIME_Absolute receive_timeout;
220 * Current value for our incremental back-off (for
223 struct GNUNET_TIME_Relative back_off;
226 * Number of bytes in received_buf that are valid.
231 * Size of received_buf.
233 unsigned int received_size;
236 * Do we have a complete response in received_buf?
241 * Are we currently busy doing receive-processing?
242 * GNUNET_YES if so, GNUNET_NO if not.
247 * Are we ignoring shutdown signals?
252 * How often have we tried to connect?
254 unsigned int attempts;
260 * Try to connect to the service.
262 * @param service_name name of service to connect to
263 * @param cfg configuration to use
264 * @param attempt counter used to alternate between IP and UNIX domain sockets
265 * @return NULL on error
267 static struct GNUNET_CONNECTION_Handle *
268 do_connect (const char *service_name,
269 const struct GNUNET_CONFIGURATION_Handle *cfg,
270 unsigned int attempt)
272 struct GNUNET_CONNECTION_Handle *sock;
275 unsigned long long port;
280 if (0 == (attempt % 2))
282 /* on even rounds, try UNIX */
284 GNUNET_CONFIGURATION_get_value_string (cfg,
286 "UNIXPATH", &unixpath)) &&
287 (0 < strlen (unixpath))) /* We have a non-NULL unixpath, does that mean it's valid? */
290 sock = GNUNET_CONNECTION_create_from_connect_to_unixpath (cfg, unixpath);
291 while ((NULL == sock) && (count < UNIXPATH_RETRIES))
294 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Failed to connect to unixpath `%s', retrying!\n", unixpath);
298 sock = GNUNET_CONNECTION_create_from_connect_to_unixpath (cfg, unixpath);
305 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Connected to unixpath `%s'!\n", unixpath);
310 GNUNET_free_non_null (unixpath);
315 GNUNET_CONFIGURATION_get_value_number (cfg,
321 GNUNET_CONFIGURATION_get_value_string (cfg,
323 "HOSTNAME", &hostname)))
325 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
327 ("Could not determine valid hostname and port for service `%s' from configuration.\n"),
331 if (0 == strlen (hostname))
333 GNUNET_free (hostname);
334 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
335 _("Need a non-empty hostname for service `%s'.\n"),
342 if (0 != (attempt % 2))
346 GNUNET_CONFIGURATION_get_value_string (cfg,
348 "UNIXPATH", &unixpath)) &&
349 (0 < strlen (unixpath)))
351 sock = GNUNET_CONNECTION_create_from_connect_to_unixpath (cfg,
353 GNUNET_free (unixpath);
361 GNUNET_log(GNUNET_ERROR_TYPE_WARNING, "Port is 0 for service `%s', unixpath didn't work, returning NULL(!)!\n", service_name);
364 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Creating from connect!\n");
365 sock = GNUNET_CONNECTION_create_from_connect (cfg,
368 GNUNET_free (hostname);
374 * Get a connection with a service.
376 * @param service_name name of the service
377 * @param cfg configuration to use
378 * @return NULL on error (service unknown to configuration)
380 struct GNUNET_CLIENT_Connection *
381 GNUNET_CLIENT_connect (const char *service_name,
382 const struct GNUNET_CONFIGURATION_Handle *cfg)
384 struct GNUNET_CLIENT_Connection *ret;
385 struct GNUNET_CONNECTION_Handle *sock;
387 sock = do_connect (service_name,
391 ret = GNUNET_malloc (sizeof (struct GNUNET_CLIENT_Connection));
394 ret->service_name = GNUNET_strdup (service_name);
395 ret->cfg = GNUNET_CONFIGURATION_dup (cfg);
396 ret->back_off = GNUNET_TIME_UNIT_MILLISECONDS;
402 * Configure this connection to ignore shutdown signals.
404 * @param h client handle
405 * @param do_ignore GNUNET_YES to ignore, GNUNET_NO to restore default
408 GNUNET_CLIENT_ignore_shutdown (struct GNUNET_CLIENT_Connection *h,
411 h->ignore_shutdown = do_ignore;
413 GNUNET_CONNECTION_ignore_shutdown (h->sock,
419 * Destroy connection with the service. This will automatically
420 * cancel any pending "receive" request (however, the handler will
421 * *NOT* be called, not even with a NULL message). Any pending
422 * transmission request will also be cancelled UNLESS the callback for
423 * the transmission request has already been called, in which case the
424 * transmission 'finish_pending_write' argument determines whether or
425 * not the write is guaranteed to complete before the socket is fully
426 * destroyed (unless, of course, there is an error with the server in
427 * which case the message may still be lost).
429 * @param finish_pending_write should a transmission already passed to the
430 * handle be completed?
431 * @param sock handle to the service connection
434 GNUNET_CLIENT_disconnect (struct GNUNET_CLIENT_Connection *sock,
435 int finish_pending_write)
437 GNUNET_assert (sock->sock != NULL);
438 if (sock->in_receive == GNUNET_YES)
440 GNUNET_CONNECTION_receive_cancel (sock->sock);
441 sock->in_receive = GNUNET_NO;
443 GNUNET_CONNECTION_destroy (sock->sock, finish_pending_write);
445 if (sock->tag != NULL)
447 GNUNET_free (sock->tag);
450 sock->receiver_handler = NULL;
451 if (sock->th != NULL)
452 GNUNET_CLIENT_notify_transmit_ready_cancel (sock->th);
453 if (sock->receive_task != GNUNET_SCHEDULER_NO_TASK)
455 GNUNET_SCHEDULER_cancel (sock->receive_task);
456 sock->receive_task = GNUNET_SCHEDULER_NO_TASK;
458 GNUNET_array_grow (sock->received_buf, sock->received_size, 0);
459 GNUNET_free (sock->service_name);
460 GNUNET_CONFIGURATION_destroy (sock->cfg);
466 * Check if message is complete
469 check_complete (struct GNUNET_CLIENT_Connection *conn)
471 if ((conn->received_pos >= sizeof (struct GNUNET_MessageHeader)) &&
472 (conn->received_pos >=
473 ntohs (((const struct GNUNET_MessageHeader *) conn->received_buf)->
475 conn->msg_complete = GNUNET_YES;
480 * Callback function for data received from the network. Note that
481 * both "available" and "errCode" would be 0 if the read simply timed out.
484 * @param buf pointer to received data
485 * @param available number of bytes availabe in "buf",
486 * possibly 0 (on errors)
487 * @param addr address of the sender
488 * @param addrlen size of addr
489 * @param errCode value of errno (on errors receiving)
492 receive_helper (void *cls,
495 const struct sockaddr *addr, socklen_t addrlen, int errCode)
497 struct GNUNET_CLIENT_Connection *conn = cls;
498 struct GNUNET_TIME_Relative remaining;
499 GNUNET_CLIENT_MessageHandler receive_handler;
500 void *receive_handler_cls;
502 GNUNET_assert (conn->msg_complete == GNUNET_NO);
503 conn->in_receive = GNUNET_NO;
504 if ((available == 0) || (conn->sock == NULL) || (errCode != 0))
506 /* signal timeout! */
508 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "timeout in receive_helper, available %d, conn->sock %s, errCode %d\n", available, conn->sock == NULL ? "NULL" : "non-NULL", errCode);
510 if (NULL != (receive_handler = conn->receiver_handler))
512 receive_handler_cls = conn->receiver_handler_cls;
513 conn->receiver_handler = NULL;
514 receive_handler (receive_handler_cls, NULL);
519 /* FIXME: optimize for common fast case where buf contains the
520 entire message and we need no copying... */
523 /* slow path: append to array */
524 if (conn->received_size < conn->received_pos + available)
525 GNUNET_array_grow (conn->received_buf,
526 conn->received_size, conn->received_pos + available);
527 memcpy (&conn->received_buf[conn->received_pos], buf, available);
528 conn->received_pos += available;
529 check_complete (conn);
530 /* check for timeout */
531 remaining = GNUNET_TIME_absolute_get_remaining (conn->receive_timeout);
532 if (remaining.rel_value == 0)
534 /* signal timeout! */
535 conn->receiver_handler (conn->receiver_handler_cls, NULL);
538 /* back to receive -- either for more data or to call callback! */
539 GNUNET_CLIENT_receive (conn,
540 conn->receiver_handler,
541 conn->receiver_handler_cls, remaining);
546 * Continuation to call the receive callback.
548 * @param cls our handle to the client connection
549 * @param tc scheduler context
552 receive_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
554 struct GNUNET_CLIENT_Connection *sock = cls;
555 GNUNET_CLIENT_MessageHandler handler = sock->receiver_handler;
556 const struct GNUNET_MessageHeader *cmsg =
557 (const struct GNUNET_MessageHeader *) sock->received_buf;
558 void *handler_cls = sock->receiver_handler_cls;
559 uint16_t msize = ntohs (cmsg->size);
561 struct GNUNET_MessageHeader *msg = (struct GNUNET_MessageHeader *) mbuf;
564 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
565 "Received message of type %u and size %u\n",
569 sock->receive_task = GNUNET_SCHEDULER_NO_TASK;
570 GNUNET_assert (GNUNET_YES == sock->msg_complete);
571 GNUNET_assert (sock->received_pos >= msize);
572 memcpy (msg, cmsg, msize);
573 memmove (sock->received_buf,
574 &sock->received_buf[msize], sock->received_pos - msize);
575 sock->received_pos -= msize;
576 sock->msg_complete = GNUNET_NO;
577 sock->receiver_handler = NULL;
578 check_complete (sock);
580 handler (handler_cls, msg);
585 * Read from the service.
587 * @param sock the service
588 * @param handler function to call with the message
589 * @param handler_cls closure for handler
590 * @param timeout how long to wait until timing out
593 GNUNET_CLIENT_receive (struct GNUNET_CLIENT_Connection *sock,
594 GNUNET_CLIENT_MessageHandler handler,
595 void *handler_cls, struct GNUNET_TIME_Relative timeout)
597 if (sock->sock == NULL)
599 /* already disconnected, fail instantly! */
600 GNUNET_break (0); /* this should not happen in well-written code! */
601 handler (handler_cls, NULL);
604 sock->receiver_handler = handler;
605 sock->receiver_handler_cls = handler_cls;
606 sock->receive_timeout = GNUNET_TIME_relative_to_absolute (timeout);
607 if (GNUNET_YES == sock->msg_complete)
609 sock->receive_task = GNUNET_SCHEDULER_add_after (GNUNET_SCHEDULER_NO_TASK,
610 &receive_task, sock);
614 GNUNET_assert (sock->in_receive == GNUNET_NO);
615 sock->in_receive = GNUNET_YES;
617 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "calling GNUNET_CONNECTION_receive\n");
619 GNUNET_CONNECTION_receive (sock->sock,
620 GNUNET_SERVER_MAX_MESSAGE_SIZE - 1,
621 timeout, &receive_helper, sock);
627 * Report service unavailable.
630 service_test_error (GNUNET_SCHEDULER_Task task, void *task_cls)
632 GNUNET_SCHEDULER_add_continuation (task,
634 GNUNET_SCHEDULER_REASON_TIMEOUT);
639 * Receive confirmation from test, service is up.
642 * @param msg message received, NULL on timeout or fatal error
645 confirm_handler (void *cls, const struct GNUNET_MessageHeader *msg)
647 struct GNUNET_CLIENT_Connection *conn = cls;
648 /* We may want to consider looking at the reply in more
649 detail in the future, for example, is this the
650 correct service? FIXME! */
654 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
655 "Received confirmation that service is running.\n");
657 GNUNET_SCHEDULER_add_continuation (conn->test_cb,
659 GNUNET_SCHEDULER_REASON_PREREQ_DONE);
663 service_test_error (conn->test_cb, conn->test_cb_cls);
665 GNUNET_CLIENT_disconnect (conn, GNUNET_NO);
670 write_test (void *cls, size_t size, void *buf)
672 struct GNUNET_CLIENT_Connection *conn = cls;
673 struct GNUNET_MessageHeader *msg;
675 if (size < sizeof (struct GNUNET_MessageHeader))
678 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
679 _("Failure to transmit TEST request.\n"));
681 service_test_error (conn->test_cb, conn->test_cb_cls);
682 GNUNET_CLIENT_disconnect (conn, GNUNET_NO);
683 return 0; /* client disconnected */
686 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
687 "Transmitting `%s' request.\n", "TEST");
689 msg = (struct GNUNET_MessageHeader *) buf;
690 msg->type = htons (GNUNET_MESSAGE_TYPE_TEST);
691 msg->size = htons (sizeof (struct GNUNET_MessageHeader));
692 GNUNET_CLIENT_receive (conn,
695 GNUNET_TIME_absolute_get_remaining (conn->test_deadline));
696 return sizeof (struct GNUNET_MessageHeader);
701 * Wait until the service is running.
703 * @param service name of the service to wait for
704 * @param cfg configuration to use
705 * @param timeout how long to wait at most in ms
706 * @param task task to run if service is running
707 * (reason will be "PREREQ_DONE" (service running)
708 * or "TIMEOUT" (service not known to be running))
709 * @param task_cls closure for task
712 GNUNET_CLIENT_service_test (const char *service,
713 const struct GNUNET_CONFIGURATION_Handle *cfg,
714 struct GNUNET_TIME_Relative timeout,
715 GNUNET_SCHEDULER_Task task, void *task_cls)
717 struct GNUNET_CLIENT_Connection *conn;
720 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
721 "Testing if service `%s' is running.\n", service);
723 conn = GNUNET_CLIENT_connect (service, cfg);
726 GNUNET_log (GNUNET_ERROR_TYPE_INFO,
728 ("Could not connect to service `%s', must not be running.\n"),
730 service_test_error (task, task_cls);
733 conn->test_cb = task;
734 conn->test_cb_cls = task_cls;
735 conn->test_deadline = GNUNET_TIME_relative_to_absolute (timeout);
737 if (NULL == GNUNET_CLIENT_notify_transmit_ready (conn,
738 sizeof (struct GNUNET_MessageHeader),
743 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
744 _("Failure to transmit request to service `%s'\n"),
746 service_test_error (task, task_cls);
747 GNUNET_CLIENT_disconnect (conn, GNUNET_NO);
754 * Connection notifies us about failure or success of
755 * a transmission request. Either pass it on to our
756 * user or, if possible, retry.
758 * @param cls our "struct GNUNET_CLIENT_TransmissionHandle"
759 * @param size number of bytes available for transmission
760 * @param buf where to write them
761 * @return number of bytes written to buf
763 static size_t client_notify (void *cls, size_t size, void *buf);
767 * This task is run if we should re-try connection to the
768 * service after a while.
770 * @param cls our "struct GNUNET_CLIENT_TransmitHandle" of the request
774 client_delayed_retry (void *cls,
775 const struct GNUNET_SCHEDULER_TaskContext *tc)
777 struct GNUNET_CLIENT_TransmitHandle *th = cls;
779 th->reconnect_task = GNUNET_SCHEDULER_NO_TASK;
780 if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
783 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
784 "Transmission failed due to shutdown.\n");
787 th->notify (th->notify_cls, 0, NULL);
791 th->th = GNUNET_CONNECTION_notify_transmit_ready (th->sock->sock,
793 GNUNET_TIME_absolute_get_remaining
799 th->notify (th->notify_cls, 0, NULL);
807 * Connection notifies us about failure or success of a transmission
808 * request. Either pass it on to our user or, if possible, retry.
810 * @param cls our "struct GNUNET_CLIENT_TransmissionHandle"
811 * @param size number of bytes available for transmission
812 * @param buf where to write them
813 * @return number of bytes written to buf
816 client_notify (void *cls, size_t size, void *buf)
818 struct GNUNET_CLIENT_TransmitHandle *th = cls;
820 struct GNUNET_TIME_Relative delay;
826 delay = GNUNET_TIME_absolute_get_remaining (th->timeout);
827 delay.rel_value /= 2;
828 if ( (0 != (GNUNET_SCHEDULER_REASON_SHUTDOWN & GNUNET_SCHEDULER_get_reason ())) ||
829 (GNUNET_YES != th->auto_retry) ||
830 (0 == --th->attempts_left) ||
831 (delay.rel_value < 1) )
834 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
835 "Transmission failed %u times, giving up.\n",
836 MAX_ATTEMPTS - th->attempts_left);
838 GNUNET_break (0 == th->notify (th->notify_cls, 0, NULL));
843 GNUNET_CONNECTION_destroy (th->sock->sock, GNUNET_NO);
844 th->sock->sock = do_connect (th->sock->service_name,
846 th->sock->attempts++);
847 GNUNET_assert (NULL != th->sock->sock);
848 GNUNET_CONNECTION_ignore_shutdown (th->sock->sock,
849 th->sock->ignore_shutdown);
850 delay = GNUNET_TIME_relative_min (delay, th->sock->back_off);
852 = GNUNET_TIME_relative_min (GNUNET_TIME_relative_multiply (th->sock->back_off, 2),
853 GNUNET_TIME_UNIT_SECONDS);
855 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
856 "Transmission failed %u times, trying again in %llums.\n",
857 MAX_ATTEMPTS - th->attempts_left,
858 (unsigned long long) delay.rel_value);
860 th->reconnect_task = GNUNET_SCHEDULER_add_delayed (delay,
861 &client_delayed_retry,
866 GNUNET_assert (size >= th->size);
867 ret = th->notify (th->notify_cls, size, buf);
874 * Ask the client to call us once the specified number of bytes
875 * are free in the transmission buffer. May call the notify
876 * method immediately if enough space is available.
878 * @param sock connection to the service
879 * @param size number of bytes to send
880 * @param timeout after how long should we give up (and call
881 * notify with buf NULL and size 0)?
882 * @param auto_retry if the connection to the service dies, should we
883 * automatically re-connect and retry (within the timeout period)
884 * or should we immediately fail in this case? Pass GNUNET_YES
885 * if the caller does not care about temporary connection errors,
886 * for example because the protocol is stateless
887 * @param notify function to call
888 * @param notify_cls closure for notify
889 * @return NULL if our buffer will never hold size bytes,
890 * a handle if the notify callback was queued (can be used to cancel)
892 struct GNUNET_CLIENT_TransmitHandle *
893 GNUNET_CLIENT_notify_transmit_ready (struct GNUNET_CLIENT_Connection *sock,
895 struct GNUNET_TIME_Relative timeout,
897 GNUNET_CONNECTION_TransmitReadyNotify
898 notify, void *notify_cls)
900 struct GNUNET_CLIENT_TransmitHandle *th;
902 if (NULL != sock->th)
904 th = GNUNET_malloc (sizeof (struct GNUNET_CLIENT_TransmitHandle));
907 th->timeout = GNUNET_TIME_relative_to_absolute (timeout);
908 th->auto_retry = auto_retry;
910 th->notify_cls = notify_cls;
911 th->attempts_left = MAX_ATTEMPTS;
912 th->th = GNUNET_CONNECTION_notify_transmit_ready (sock->sock,
928 * Cancel a request for notification.
930 * @param th handle from the original request.
933 GNUNET_CLIENT_notify_transmit_ready_cancel (struct
934 GNUNET_CLIENT_TransmitHandle *th)
936 if (th->reconnect_task != GNUNET_SCHEDULER_NO_TASK)
938 GNUNET_break (NULL == th->th);
939 GNUNET_SCHEDULER_cancel (th->reconnect_task);
940 th->reconnect_task = GNUNET_SCHEDULER_NO_TASK;
944 GNUNET_assert (NULL != th->th);
945 GNUNET_CONNECTION_notify_transmit_ready_cancel (th->th);
953 * Function called to notify a client about the socket
954 * begin ready to queue the message. "buf" will be
955 * NULL and "size" zero if the socket was closed for
956 * writing in the meantime.
958 * @param cls closure of type "struct TransmitGetResponseContext*"
959 * @param size number of bytes available in buf
960 * @param buf where the callee should write the message
961 * @return number of bytes written to buf
964 transmit_for_response (void *cls, size_t size, void *buf)
966 struct TransmitGetResponseContext *tc = cls;
969 tc->sock->tag = NULL;
970 msize = ntohs (tc->hdr->size);
974 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
975 _("Could not submit request, not expecting to receive a response.\n"));
977 tc->rn (tc->rn_cls, NULL);
981 GNUNET_assert (size >= msize);
982 memcpy (buf, tc->hdr, msize);
983 GNUNET_CLIENT_receive (tc->sock,
986 GNUNET_TIME_absolute_get_remaining (tc->timeout));
993 * Convenience API that combines sending a request
994 * to the service and waiting for a response.
995 * If either operation times out, the callback
996 * will be called with a "NULL" response (in which
997 * case the connection should probably be destroyed).
999 * @param sock connection to use
1000 * @param hdr message to transmit
1001 * @param timeout when to give up (for both transmission
1002 * and for waiting for a response)
1003 * @param auto_retry if the connection to the service dies, should we
1004 * automatically re-connect and retry (within the timeout period)
1005 * or should we immediately fail in this case? Pass GNUNET_YES
1006 * if the caller does not care about temporary connection errors,
1007 * for example because the protocol is stateless
1008 * @param rn function to call with the response
1009 * @param rn_cls closure for rn
1010 * @return GNUNET_OK on success, GNUNET_SYSERR if a request
1011 * is already pending
1014 GNUNET_CLIENT_transmit_and_get_response (struct GNUNET_CLIENT_Connection
1016 const struct GNUNET_MessageHeader
1018 struct GNUNET_TIME_Relative timeout,
1020 GNUNET_CLIENT_MessageHandler rn,
1023 struct TransmitGetResponseContext *tc;
1026 if (NULL != sock->th)
1027 return GNUNET_SYSERR;
1028 GNUNET_assert (sock->tag == NULL);
1029 msize = ntohs (hdr->size);
1030 tc = GNUNET_malloc (sizeof (struct TransmitGetResponseContext) + msize);
1032 tc->hdr = (const struct GNUNET_MessageHeader *) &tc[1];
1033 memcpy (&tc[1], hdr, msize);
1034 tc->timeout = GNUNET_TIME_relative_to_absolute (timeout);
1036 tc->rn_cls = rn_cls;
1037 if (NULL == GNUNET_CLIENT_notify_transmit_ready (sock,
1041 &transmit_for_response,
1046 return GNUNET_SYSERR;
1054 /* end of client.c */