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
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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.
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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
48 * Handle for a transmission request.
50 struct GNUNET_CLIENT_TransmitHandle
55 struct GNUNET_CLIENT_Connection *sock;
58 * Function to call to get the data for transmission.
60 GNUNET_CONNECTION_TransmitReadyNotify notify;
68 * Handle to the transmission with the underlying
71 struct GNUNET_CONNECTION_TransmitHandle *th;
74 * If we are re-trying and are delaying to do so,
75 * handle to the scheduled task managing the delay.
77 GNUNET_SCHEDULER_TaskIdentifier reconnect_task;
80 * Timeout for the operation overall.
82 struct GNUNET_TIME_Absolute timeout;
85 * Number of bytes requested.
90 * Are we allowed to re-try to connect without telling
91 * the user (of this API) about the connection troubles?
96 * Number of attempts left for transmitting the request. We may
97 * fail the first time (say because the service is not yet up), in
98 * which case (if auto_retry is set) we wait a bit and re-try
99 * (timeout permitting).
101 unsigned int attempts_left;
107 * Context for processing
108 * "GNUNET_CLIENT_transmit_and_get_response" requests.
110 struct TransmitGetResponseContext
115 struct GNUNET_CLIENT_Connection *sock;
118 * Message to transmit; do not free, allocated
119 * right after this struct.
121 const struct GNUNET_MessageHeader *hdr;
126 struct GNUNET_TIME_Absolute timeout;
129 * Function to call when done.
131 GNUNET_CLIENT_MessageHandler rn;
140 * Struct to refer to a GNUnet TCP connection.
141 * This is more than just a socket because if the server
142 * drops the connection, the client automatically tries
143 * to reconnect (and for that needs connection information).
145 struct GNUNET_CLIENT_Connection
149 * the socket handle, NULL if not live
151 struct GNUNET_CONNECTION_Handle *sock;
156 struct GNUNET_SCHEDULER_Handle *sched;
160 * FIXME: why do we DUP the configuration? Avoid this!
162 struct GNUNET_CONFIGURATION_Handle *cfg;
165 * Name of the service we interact with.
170 * Context of a transmit_and_get_response operation, NULL
171 * if no such operation is pending.
173 struct TransmitGetResponseContext *tag;
176 * Handler for current receiver task.
178 GNUNET_CLIENT_MessageHandler receiver_handler;
181 * Closure for receiver_handler.
183 void *receiver_handler_cls;
186 * Handle for a pending transmission request, NULL if there is
189 struct GNUNET_CLIENT_TransmitHandle *th;
192 * Handler for service test completion (NULL unless in service_test)
194 GNUNET_SCHEDULER_Task test_cb;
197 * Deadline for calling 'test_cb'.
199 struct GNUNET_TIME_Absolute test_deadline;
202 * If we are re-trying and are delaying to do so,
203 * handle to the scheduled task managing the delay.
205 GNUNET_SCHEDULER_TaskIdentifier receive_task;
208 * Closure for test_cb (NULL unless in service_test)
213 * Buffer for received message.
218 * Timeout for receiving a response (absolute time).
220 struct GNUNET_TIME_Absolute receive_timeout;
223 * Current value for our incremental back-off (for
226 struct GNUNET_TIME_Relative back_off;
229 * Number of bytes in received_buf that are valid.
234 * Size of received_buf.
236 unsigned int received_size;
239 * Do we have a complete response in received_buf?
244 * Are we currently busy doing receive-processing?
245 * GNUNET_YES if so, GNUNET_NO if not.
250 * Are we ignoring shutdown signals?
255 * How often have we tried to connect?
257 unsigned int attempts;
263 * Try to connect to the service.
265 * @param sched scheduler to use
266 * @param service_name name of service to connect to
267 * @param cfg configuration to use
268 * @param attempt counter used to alternate between IP and UNIX domain sockets
269 * @return NULL on error
271 static struct GNUNET_CONNECTION_Handle *
272 do_connect (struct GNUNET_SCHEDULER_Handle *sched,
273 const char *service_name,
274 const struct GNUNET_CONFIGURATION_Handle *cfg,
275 unsigned int attempt)
277 struct GNUNET_CONNECTION_Handle *sock;
280 unsigned long long port;
283 if (0 == attempt % 2)
285 /* on even rounds, try UNIX */
287 GNUNET_CONFIGURATION_get_value_string (cfg,
289 "UNIXPATH", &unixpath))
291 sock = GNUNET_CONNECTION_create_from_connect_to_unixpath (sched,
294 GNUNET_SERVER_MAX_MESSAGE_SIZE - 1);
295 GNUNET_free (unixpath);
303 GNUNET_CONFIGURATION_get_value_number (cfg,
309 GNUNET_CONFIGURATION_get_value_string (cfg,
311 "HOSTNAME", &hostname)))
313 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
315 ("Could not determine valid hostname and port for service `%s' from configuration.\n"),
319 if (0 == strlen (hostname))
321 GNUNET_free (hostname);
322 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
323 _("Need a non-empty hostname for service `%s'.\n"),
327 sock = GNUNET_CONNECTION_create_from_connect (sched,
331 GNUNET_SERVER_MAX_MESSAGE_SIZE - 1);
332 GNUNET_free (hostname);
338 * Get a connection with a service.
340 * @param sched scheduler to use
341 * @param service_name name of the service
342 * @param cfg configuration to use
343 * @return NULL on error (service unknown to configuration)
345 struct GNUNET_CLIENT_Connection *
346 GNUNET_CLIENT_connect (struct GNUNET_SCHEDULER_Handle *sched,
347 const char *service_name,
348 const struct GNUNET_CONFIGURATION_Handle *cfg)
350 struct GNUNET_CLIENT_Connection *ret;
351 struct GNUNET_CONNECTION_Handle *sock;
353 sock = do_connect (sched,
358 ret = GNUNET_malloc (sizeof (struct GNUNET_CLIENT_Connection));
362 ret->service_name = GNUNET_strdup (service_name);
363 ret->cfg = GNUNET_CONFIGURATION_dup (cfg);
364 ret->back_off = GNUNET_TIME_UNIT_MILLISECONDS;
370 * Configure this connection to ignore shutdown signals.
372 * @param h client handle
373 * @param do_ignore GNUNET_YES to ignore, GNUNET_NO to restore default
376 GNUNET_CLIENT_ignore_shutdown (struct GNUNET_CLIENT_Connection *h,
379 h->ignore_shutdown = do_ignore;
381 GNUNET_CONNECTION_ignore_shutdown (h->sock,
387 * Destroy connection with the service. This will automatically
388 * cancel any pending "receive" request (however, the handler will
389 * *NOT* be called, not even with a NULL message). Any pending
390 * transmission request will also be cancelled UNLESS the callback for
391 * the transmission request has already been called, in which case the
392 * transmission 'finish_pending_write' argument determines whether or
393 * not the write is guaranteed to complete before the socket is fully
394 * destroyed (unless, of course, there is an error with the server in
395 * which case the message may still be lost).
397 * @param finish_pending_write should a transmission already passed to the
398 * handle be completed?
399 * @param sock handle to the service connection
402 GNUNET_CLIENT_disconnect (struct GNUNET_CLIENT_Connection *sock,
403 int finish_pending_write)
405 GNUNET_assert (sock->sock != NULL);
406 if (sock->in_receive == GNUNET_YES)
408 GNUNET_CONNECTION_receive_cancel (sock->sock);
409 sock->in_receive = GNUNET_NO;
411 GNUNET_CONNECTION_destroy (sock->sock, finish_pending_write);
413 if (sock->tag != NULL)
415 GNUNET_free (sock->tag);
418 sock->receiver_handler = NULL;
419 if (sock->th != NULL)
420 GNUNET_CLIENT_notify_transmit_ready_cancel (sock->th);
421 if (sock->receive_task != GNUNET_SCHEDULER_NO_TASK)
423 GNUNET_SCHEDULER_cancel (sock->sched, sock->receive_task);
424 sock->receive_task = GNUNET_SCHEDULER_NO_TASK;
426 GNUNET_array_grow (sock->received_buf, sock->received_size, 0);
427 GNUNET_free (sock->service_name);
428 GNUNET_CONFIGURATION_destroy (sock->cfg);
434 * Check if message is complete
437 check_complete (struct GNUNET_CLIENT_Connection *conn)
439 if ((conn->received_pos >= sizeof (struct GNUNET_MessageHeader)) &&
440 (conn->received_pos >=
441 ntohs (((const struct GNUNET_MessageHeader *) conn->received_buf)->
443 conn->msg_complete = GNUNET_YES;
448 * Callback function for data received from the network. Note that
449 * both "available" and "errCode" would be 0 if the read simply timed out.
452 * @param buf pointer to received data
453 * @param available number of bytes availabe in "buf",
454 * possibly 0 (on errors)
455 * @param addr address of the sender
456 * @param addrlen size of addr
457 * @param errCode value of errno (on errors receiving)
460 receive_helper (void *cls,
463 const struct sockaddr *addr, socklen_t addrlen, int errCode)
465 struct GNUNET_CLIENT_Connection *conn = cls;
466 struct GNUNET_TIME_Relative remaining;
467 GNUNET_CLIENT_MessageHandler receive_handler;
468 void *receive_handler_cls;
470 GNUNET_assert (conn->msg_complete == GNUNET_NO);
471 conn->in_receive = GNUNET_NO;
472 if ((available == 0) || (conn->sock == NULL) || (errCode != 0))
474 /* signal timeout! */
475 if (NULL != (receive_handler = conn->receiver_handler))
477 receive_handler_cls = conn->receiver_handler_cls;
478 conn->receiver_handler = NULL;
479 receive_handler (receive_handler_cls, NULL);
484 /* FIXME: optimize for common fast case where buf contains the
485 entire message and we need no copying... */
488 /* slow path: append to array */
489 if (conn->received_size < conn->received_pos + available)
490 GNUNET_array_grow (conn->received_buf,
491 conn->received_size, conn->received_pos + available);
492 memcpy (&conn->received_buf[conn->received_pos], buf, available);
493 conn->received_pos += available;
494 check_complete (conn);
495 /* check for timeout */
496 remaining = GNUNET_TIME_absolute_get_remaining (conn->receive_timeout);
497 if (remaining.value == 0)
499 /* signal timeout! */
500 conn->receiver_handler (conn->receiver_handler_cls, NULL);
503 /* back to receive -- either for more data or to call callback! */
504 GNUNET_CLIENT_receive (conn,
505 conn->receiver_handler,
506 conn->receiver_handler_cls, remaining);
511 * Continuation to call the receive callback.
513 * @param cls our handle to the client connection
514 * @param tc scheduler context
517 receive_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
519 struct GNUNET_CLIENT_Connection *sock = cls;
520 GNUNET_CLIENT_MessageHandler handler = sock->receiver_handler;
521 const struct GNUNET_MessageHeader *cmsg =
522 (const struct GNUNET_MessageHeader *) sock->received_buf;
523 void *handler_cls = sock->receiver_handler_cls;
524 uint16_t msize = ntohs (cmsg->size);
526 struct GNUNET_MessageHeader *msg = (struct GNUNET_MessageHeader *) mbuf;
529 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
530 "Received message of size %u\n",
533 sock->receive_task = GNUNET_SCHEDULER_NO_TASK;
534 GNUNET_assert (GNUNET_YES == sock->msg_complete);
535 GNUNET_assert (sock->received_pos >= msize);
536 memcpy (msg, cmsg, msize);
537 memmove (sock->received_buf,
538 &sock->received_buf[msize], sock->received_pos - msize);
539 sock->received_pos -= msize;
540 sock->msg_complete = GNUNET_NO;
541 sock->receiver_handler = NULL;
542 check_complete (sock);
544 handler (handler_cls, msg);
549 * Read from the service.
551 * @param sock the service
552 * @param handler function to call with the message
553 * @param handler_cls closure for handler
554 * @param timeout how long to wait until timing out
557 GNUNET_CLIENT_receive (struct GNUNET_CLIENT_Connection *sock,
558 GNUNET_CLIENT_MessageHandler handler,
559 void *handler_cls, struct GNUNET_TIME_Relative timeout)
561 if (sock->sock == NULL)
563 /* already disconnected, fail instantly! */
564 GNUNET_break (0); /* this should not happen in well-written code! */
565 handler (handler_cls, NULL);
568 sock->receiver_handler = handler;
569 sock->receiver_handler_cls = handler_cls;
570 sock->receive_timeout = GNUNET_TIME_relative_to_absolute (timeout);
571 if (GNUNET_YES == sock->msg_complete)
573 sock->receive_task = GNUNET_SCHEDULER_add_after (sock->sched,
574 GNUNET_SCHEDULER_NO_TASK,
575 &receive_task, sock);
579 GNUNET_assert (sock->in_receive == GNUNET_NO);
580 sock->in_receive = GNUNET_YES;
581 GNUNET_CONNECTION_receive (sock->sock,
582 GNUNET_SERVER_MAX_MESSAGE_SIZE - 1,
583 timeout, &receive_helper, sock);
589 * Report service unavailable.
592 service_test_error (struct GNUNET_SCHEDULER_Handle *s,
593 GNUNET_SCHEDULER_Task task, void *task_cls)
595 GNUNET_SCHEDULER_add_continuation (s,
598 GNUNET_SCHEDULER_REASON_TIMEOUT);
603 * Receive confirmation from test, service is up.
606 * @param msg message received, NULL on timeout or fatal error
609 confirm_handler (void *cls, const struct GNUNET_MessageHeader *msg)
611 struct GNUNET_CLIENT_Connection *conn = cls;
612 /* We may want to consider looking at the reply in more
613 detail in the future, for example, is this the
614 correct service? FIXME! */
618 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
619 "Received confirmation that service is running.\n");
621 GNUNET_SCHEDULER_add_continuation (conn->sched,
624 GNUNET_SCHEDULER_REASON_PREREQ_DONE);
628 service_test_error (conn->sched, conn->test_cb, conn->test_cb_cls);
630 GNUNET_CLIENT_disconnect (conn, GNUNET_NO);
635 write_test (void *cls, size_t size, void *buf)
637 struct GNUNET_CLIENT_Connection *conn = cls;
638 struct GNUNET_MessageHeader *msg;
640 if (size < sizeof (struct GNUNET_MessageHeader))
643 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
644 _("Failure to transmit TEST request.\n"));
646 service_test_error (conn->sched, conn->test_cb, conn->test_cb_cls);
647 GNUNET_CLIENT_disconnect (conn, GNUNET_NO);
648 return 0; /* client disconnected */
651 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
652 "Transmitting `%s' request.\n", "TEST");
654 msg = (struct GNUNET_MessageHeader *) buf;
655 msg->type = htons (GNUNET_MESSAGE_TYPE_TEST);
656 msg->size = htons (sizeof (struct GNUNET_MessageHeader));
657 GNUNET_CLIENT_receive (conn,
660 GNUNET_TIME_absolute_get_remaining (conn->test_deadline));
661 return sizeof (struct GNUNET_MessageHeader);
666 * Wait until the service is running.
668 * @param sched scheduler to use
669 * @param service name of the service to wait for
670 * @param cfg configuration to use
671 * @param timeout how long to wait at most in ms
672 * @param task task to run if service is running
673 * (reason will be "PREREQ_DONE" (service running)
674 * or "TIMEOUT" (service not known to be running))
675 * @param task_cls closure for task
678 GNUNET_CLIENT_service_test (struct GNUNET_SCHEDULER_Handle *sched,
680 const struct GNUNET_CONFIGURATION_Handle *cfg,
681 struct GNUNET_TIME_Relative timeout,
682 GNUNET_SCHEDULER_Task task, void *task_cls)
684 struct GNUNET_CLIENT_Connection *conn;
687 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
688 "Testing if service `%s' is running.\n", service);
690 conn = GNUNET_CLIENT_connect (sched, service, cfg);
693 GNUNET_log (GNUNET_ERROR_TYPE_INFO,
695 ("Could not connect to service `%s', must not be running.\n"),
697 service_test_error (sched, task, task_cls);
700 conn->test_cb = task;
701 conn->test_cb_cls = task_cls;
702 conn->test_deadline = GNUNET_TIME_relative_to_absolute (timeout);
704 if (NULL == GNUNET_CLIENT_notify_transmit_ready (conn,
705 sizeof (struct GNUNET_MessageHeader),
710 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
711 _("Failure to transmit request to service `%s'\n"),
713 service_test_error (sched, task, task_cls);
714 GNUNET_CLIENT_disconnect (conn, GNUNET_NO);
721 * Connection notifies us about failure or success of
722 * a transmission request. Either pass it on to our
723 * user or, if possible, retry.
725 * @param cls our "struct GNUNET_CLIENT_TransmissionHandle"
726 * @param size number of bytes available for transmission
727 * @param buf where to write them
728 * @return number of bytes written to buf
730 static size_t client_notify (void *cls, size_t size, void *buf);
734 * This task is run if we should re-try connection to the
735 * service after a while.
737 * @param cls our "struct GNUNET_CLIENT_TransmitHandle" of the request
741 client_delayed_retry (void *cls,
742 const struct GNUNET_SCHEDULER_TaskContext *tc)
744 struct GNUNET_CLIENT_TransmitHandle *th = cls;
746 th->reconnect_task = GNUNET_SCHEDULER_NO_TASK;
747 if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
750 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
751 "Transmission failed due to shutdown.\n");
754 th->notify (th->notify_cls, 0, NULL);
758 th->th = GNUNET_CONNECTION_notify_transmit_ready (th->sock->sock,
760 GNUNET_TIME_absolute_get_remaining
766 th->notify (th->notify_cls, 0, NULL);
774 * Connection notifies us about failure or success of a transmission
775 * request. Either pass it on to our user or, if possible, retry.
777 * @param cls our "struct GNUNET_CLIENT_TransmissionHandle"
778 * @param size number of bytes available for transmission
779 * @param buf where to write them
780 * @return number of bytes written to buf
783 client_notify (void *cls, size_t size, void *buf)
785 struct GNUNET_CLIENT_TransmitHandle *th = cls;
787 struct GNUNET_TIME_Relative delay;
793 delay = GNUNET_TIME_absolute_get_remaining (th->timeout);
795 if ( (0 != (GNUNET_SCHEDULER_REASON_SHUTDOWN & GNUNET_SCHEDULER_get_reason (th->sock->sched))) ||
796 (GNUNET_YES != th->auto_retry) ||
797 (0 == --th->attempts_left) ||
801 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
802 "Transmission failed %u times, giving up.\n",
803 MAX_ATTEMPTS - th->attempts_left);
805 GNUNET_break (0 == th->notify (th->notify_cls, 0, NULL));
810 GNUNET_CONNECTION_destroy (th->sock->sock, GNUNET_NO);
811 th->sock->sock = do_connect (th->sock->sched,
812 th->sock->service_name,
814 th->sock->attempts++);
815 GNUNET_assert (NULL != th->sock->sock);
816 GNUNET_CONNECTION_ignore_shutdown (th->sock->sock,
817 th->sock->ignore_shutdown);
818 delay = GNUNET_TIME_relative_min (delay, th->sock->back_off);
820 = GNUNET_TIME_relative_min (GNUNET_TIME_relative_multiply (th->sock->back_off, 2),
821 GNUNET_TIME_UNIT_SECONDS);
823 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
824 "Transmission failed %u times, trying again in %llums.\n",
825 MAX_ATTEMPTS - th->attempts_left,
826 (unsigned long long) delay.value);
828 th->reconnect_task = GNUNET_SCHEDULER_add_delayed (th->sock->sched,
830 &client_delayed_retry,
835 GNUNET_assert (size >= th->size);
836 ret = th->notify (th->notify_cls, size, buf);
843 * Ask the client to call us once the specified number of bytes
844 * are free in the transmission buffer. May call the notify
845 * method immediately if enough space is available.
847 * @param sock connection to the service
848 * @param size number of bytes to send
849 * @param timeout after how long should we give up (and call
850 * notify with buf NULL and size 0)?
851 * @param auto_retry if the connection to the service dies, should we
852 * automatically re-connect and retry (within the timeout period)
853 * or should we immediately fail in this case? Pass GNUNET_YES
854 * if the caller does not care about temporary connection errors,
855 * for example because the protocol is stateless
856 * @param notify function to call
857 * @param notify_cls closure for notify
858 * @return NULL if our buffer will never hold size bytes,
859 * a handle if the notify callback was queued (can be used to cancel)
861 struct GNUNET_CLIENT_TransmitHandle *
862 GNUNET_CLIENT_notify_transmit_ready (struct GNUNET_CLIENT_Connection *sock,
864 struct GNUNET_TIME_Relative timeout,
866 GNUNET_CONNECTION_TransmitReadyNotify
867 notify, void *notify_cls)
869 struct GNUNET_CLIENT_TransmitHandle *th;
871 if (NULL != sock->th)
873 th = GNUNET_malloc (sizeof (struct GNUNET_CLIENT_TransmitHandle));
876 th->timeout = GNUNET_TIME_relative_to_absolute (timeout);
877 th->auto_retry = auto_retry;
879 th->notify_cls = notify_cls;
880 th->attempts_left = MAX_ATTEMPTS;
881 th->th = GNUNET_CONNECTION_notify_transmit_ready (sock->sock,
897 * Cancel a request for notification.
899 * @param th handle from the original request.
902 GNUNET_CLIENT_notify_transmit_ready_cancel (struct
903 GNUNET_CLIENT_TransmitHandle *th)
905 if (th->reconnect_task != GNUNET_SCHEDULER_NO_TASK)
907 GNUNET_break (NULL == th->th);
908 GNUNET_SCHEDULER_cancel (th->sock->sched, th->reconnect_task);
909 th->reconnect_task = GNUNET_SCHEDULER_NO_TASK;
913 GNUNET_break (NULL != th->th);
914 GNUNET_CONNECTION_notify_transmit_ready_cancel (th->th);
922 * Function called to notify a client about the socket
923 * begin ready to queue the message. "buf" will be
924 * NULL and "size" zero if the socket was closed for
925 * writing in the meantime.
927 * @param cls closure of type "struct TransmitGetResponseContext*"
928 * @param size number of bytes available in buf
929 * @param buf where the callee should write the message
930 * @return number of bytes written to buf
933 transmit_for_response (void *cls, size_t size, void *buf)
935 struct TransmitGetResponseContext *tc = cls;
938 tc->sock->tag = NULL;
939 msize = ntohs (tc->hdr->size);
943 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
944 _("Could not submit request, not expecting to receive a response.\n"));
946 tc->rn (tc->rn_cls, NULL);
950 GNUNET_assert (size >= msize);
951 memcpy (buf, tc->hdr, msize);
952 GNUNET_CLIENT_receive (tc->sock,
955 GNUNET_TIME_absolute_get_remaining (tc->timeout));
962 * Convenience API that combines sending a request
963 * to the service and waiting for a response.
964 * If either operation times out, the callback
965 * will be called with a "NULL" response (in which
966 * case the connection should probably be destroyed).
968 * @param sock connection to use
969 * @param hdr message to transmit
970 * @param timeout when to give up (for both transmission
971 * and for waiting for a response)
972 * @param auto_retry if the connection to the service dies, should we
973 * automatically re-connect and retry (within the timeout period)
974 * or should we immediately fail in this case? Pass GNUNET_YES
975 * if the caller does not care about temporary connection errors,
976 * for example because the protocol is stateless
977 * @param rn function to call with the response
978 * @param rn_cls closure for rn
979 * @return GNUNET_OK on success, GNUNET_SYSERR if a request
983 GNUNET_CLIENT_transmit_and_get_response (struct GNUNET_CLIENT_Connection
985 const struct GNUNET_MessageHeader
987 struct GNUNET_TIME_Relative timeout,
989 GNUNET_CLIENT_MessageHandler rn,
992 struct TransmitGetResponseContext *tc;
995 if (NULL != sock->th)
996 return GNUNET_SYSERR;
997 GNUNET_assert (sock->tag == NULL);
998 msize = ntohs (hdr->size);
999 tc = GNUNET_malloc (sizeof (struct TransmitGetResponseContext) + msize);
1001 tc->hdr = (const struct GNUNET_MessageHeader *) &tc[1];
1002 memcpy (&tc[1], hdr, msize);
1003 tc->timeout = GNUNET_TIME_relative_to_absolute (timeout);
1005 tc->rn_cls = rn_cls;
1006 if (NULL == GNUNET_CLIENT_notify_transmit_ready (sock,
1010 &transmit_for_response,
1015 return GNUNET_SYSERR;
1023 /* end of client.c */