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
47 * Handle for a transmission request.
49 struct GNUNET_CLIENT_TransmitHandle
54 struct GNUNET_CLIENT_Connection *sock;
57 * Function to call to get the data for transmission.
59 GNUNET_CONNECTION_TransmitReadyNotify notify;
67 * Handle to the transmission with the underlying
70 struct GNUNET_CONNECTION_TransmitHandle *th;
73 * If we are re-trying and are delaying to do so,
74 * handle to the scheduled task managing the delay.
76 GNUNET_SCHEDULER_TaskIdentifier reconnect_task;
79 * Timeout for the operation overall.
81 struct GNUNET_TIME_Absolute timeout;
84 * Number of bytes requested.
89 * Are we allowed to re-try to connect without telling
90 * the user (of this API) about the connection troubles?
95 * Number of attempts left for transmitting the request. We may
96 * fail the first time (say because the service is not yet up), in
97 * which case (if auto_retry is set) we wait a bit and re-try
98 * (timeout permitting).
100 unsigned int attempts_left;
106 * Context for processing
107 * "GNUNET_CLIENT_transmit_and_get_response" requests.
109 struct TransmitGetResponseContext
114 struct GNUNET_CLIENT_Connection *sock;
117 * Message to transmit; do not free, allocated
118 * right after this struct.
120 const struct GNUNET_MessageHeader *hdr;
125 struct GNUNET_TIME_Absolute timeout;
128 * Function to call when done.
130 GNUNET_CLIENT_MessageHandler rn;
139 * Struct to refer to a GNUnet TCP connection.
140 * This is more than just a socket because if the server
141 * drops the connection, the client automatically tries
142 * to reconnect (and for that needs connection information).
144 struct GNUNET_CLIENT_Connection
148 * the socket handle, NULL if not live
150 struct GNUNET_CONNECTION_Handle *sock;
155 const struct GNUNET_CONFIGURATION_Handle *cfg;
158 * Name of the service we interact with.
163 * Context of a transmit_and_get_response operation, NULL
164 * if no such operation is pending.
166 struct TransmitGetResponseContext *tag;
169 * Handler for current receiver task.
171 GNUNET_CLIENT_MessageHandler receiver_handler;
174 * Closure for receiver_handler.
176 void *receiver_handler_cls;
179 * Handle for a pending transmission request, NULL if there is
182 struct GNUNET_CLIENT_TransmitHandle *th;
185 * Handler for service test completion (NULL unless in service_test)
187 GNUNET_SCHEDULER_Task test_cb;
190 * Deadline for calling 'test_cb'.
192 struct GNUNET_TIME_Absolute test_deadline;
195 * If we are re-trying and are delaying to do so,
196 * handle to the scheduled task managing the delay.
198 GNUNET_SCHEDULER_TaskIdentifier receive_task;
201 * Closure for test_cb (NULL unless in service_test)
206 * Buffer for received message.
211 * Timeout for receiving a response (absolute time).
213 struct GNUNET_TIME_Absolute receive_timeout;
216 * Current value for our incremental back-off (for
219 struct GNUNET_TIME_Relative back_off;
222 * Number of bytes in received_buf that are valid.
227 * Size of received_buf.
229 unsigned int received_size;
232 * Do we have a complete response in received_buf?
237 * Are we currently busy doing receive-processing?
238 * GNUNET_YES if so, GNUNET_NO if not.
243 * Are we ignoring shutdown signals?
248 * How often have we tried to connect?
250 unsigned int attempts;
256 * Try to connect to the service.
258 * @param service_name name of service to connect to
259 * @param cfg configuration to use
260 * @param attempt counter used to alternate between IP and UNIX domain sockets
261 * @return NULL on error
263 static struct GNUNET_CONNECTION_Handle *
264 do_connect (const char *service_name,
265 const struct GNUNET_CONFIGURATION_Handle *cfg,
266 unsigned int attempt)
268 struct GNUNET_CONNECTION_Handle *sock;
271 unsigned long long port;
275 if (0 == (attempt % 2))
277 /* on even rounds, try UNIX */
279 GNUNET_CONFIGURATION_get_value_string (cfg,
281 "UNIXPATH", &unixpath)) &&
282 (0 < strlen (unixpath))) /* We have a non-NULL unixpath, does that mean it's valid? */
284 sock = GNUNET_CONNECTION_create_from_connect_to_unixpath (cfg, unixpath);
288 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Connected to unixpath `%s'!\n", unixpath);
290 GNUNET_free(unixpath);
294 GNUNET_free_non_null (unixpath);
299 GNUNET_CONFIGURATION_get_value_number (cfg,
305 GNUNET_CONFIGURATION_get_value_string (cfg,
307 "HOSTNAME", &hostname)))
309 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
310 _("Could not determine valid hostname and port for service `%s' from configuration.\n"),
314 if (0 == strlen (hostname))
316 GNUNET_free (hostname);
317 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
318 _("Need a non-empty hostname for service `%s'.\n"),
325 if (0 != (attempt % 2))
329 GNUNET_CONFIGURATION_get_value_string (cfg,
331 "UNIXPATH", &unixpath)) &&
332 (0 < strlen (unixpath)))
334 sock = GNUNET_CONNECTION_create_from_connect_to_unixpath (cfg,
336 GNUNET_free (unixpath);
339 GNUNET_free (hostname);
346 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
347 "Port is 0 for service `%s', UNIXPATH did not work, returning NULL!\n",
350 GNUNET_free (hostname);
354 sock = GNUNET_CONNECTION_create_from_connect (cfg,
357 GNUNET_free (hostname);
363 * Get a connection with a service.
365 * @param service_name name of the service
366 * @param cfg configuration to use
367 * @return NULL on error (service unknown to configuration)
369 struct GNUNET_CLIENT_Connection *
370 GNUNET_CLIENT_connect (const char *service_name,
371 const struct GNUNET_CONFIGURATION_Handle *cfg)
373 struct GNUNET_CLIENT_Connection *ret;
374 struct GNUNET_CONNECTION_Handle *sock;
376 sock = do_connect (service_name,
378 ret = GNUNET_malloc (sizeof (struct GNUNET_CLIENT_Connection));
381 ret->service_name = GNUNET_strdup (service_name);
383 ret->back_off = GNUNET_TIME_UNIT_MILLISECONDS;
389 * Configure this connection to ignore shutdown signals.
391 * @param h client handle
392 * @param do_ignore GNUNET_YES to ignore, GNUNET_NO to restore default
395 GNUNET_CLIENT_ignore_shutdown (struct GNUNET_CLIENT_Connection *h,
398 h->ignore_shutdown = do_ignore;
400 GNUNET_CONNECTION_ignore_shutdown (h->sock,
406 * Destroy connection with the service. This will automatically
407 * cancel any pending "receive" request (however, the handler will
408 * *NOT* be called, not even with a NULL message). Any pending
409 * transmission request will also be cancelled UNLESS the callback for
410 * the transmission request has already been called, in which case the
411 * transmission 'finish_pending_write' argument determines whether or
412 * not the write is guaranteed to complete before the socket is fully
413 * destroyed (unless, of course, there is an error with the server in
414 * which case the message may still be lost).
416 * @param finish_pending_write should a transmission already passed to the
417 * handle be completed?
418 * @param sock handle to the service connection
421 GNUNET_CLIENT_disconnect (struct GNUNET_CLIENT_Connection *sock,
422 int finish_pending_write)
424 if (sock->in_receive == GNUNET_YES)
426 GNUNET_CONNECTION_receive_cancel (sock->sock);
427 sock->in_receive = GNUNET_NO;
429 if (sock->th != NULL)
431 GNUNET_CLIENT_notify_transmit_ready_cancel (sock->th);
434 if (NULL != sock->sock)
436 GNUNET_CONNECTION_destroy (sock->sock, finish_pending_write);
439 if (sock->receive_task != GNUNET_SCHEDULER_NO_TASK)
441 GNUNET_SCHEDULER_cancel (sock->receive_task);
442 sock->receive_task = GNUNET_SCHEDULER_NO_TASK;
444 if (sock->tag != NULL)
446 GNUNET_free (sock->tag);
449 sock->receiver_handler = NULL;
450 GNUNET_array_grow (sock->received_buf, sock->received_size, 0);
451 GNUNET_free (sock->service_name);
457 * Check if message is complete
460 check_complete (struct GNUNET_CLIENT_Connection *conn)
462 if ((conn->received_pos >= sizeof (struct GNUNET_MessageHeader)) &&
463 (conn->received_pos >=
464 ntohs (((const struct GNUNET_MessageHeader *) conn->received_buf)->
466 conn->msg_complete = GNUNET_YES;
471 * Callback function for data received from the network. Note that
472 * both "available" and "errCode" would be 0 if the read simply timed out.
475 * @param buf pointer to received data
476 * @param available number of bytes availabe in "buf",
477 * possibly 0 (on errors)
478 * @param addr address of the sender
479 * @param addrlen size of addr
480 * @param errCode value of errno (on errors receiving)
483 receive_helper (void *cls,
486 const struct sockaddr *addr, socklen_t addrlen, int errCode)
488 struct GNUNET_CLIENT_Connection *conn = cls;
489 struct GNUNET_TIME_Relative remaining;
490 GNUNET_CLIENT_MessageHandler receive_handler;
491 void *receive_handler_cls;
493 GNUNET_assert (conn->msg_complete == GNUNET_NO);
494 conn->in_receive = GNUNET_NO;
495 if ((available == 0) || (conn->sock == NULL) || (errCode != 0))
497 /* signal timeout! */
499 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
500 "Timeout in receive_helper, available %u, conn->sock %s, errCode `%s'\n",
501 (unsigned int) available,
502 conn->sock == NULL ? "NULL" : "non-NULL",
505 if (NULL != (receive_handler = conn->receiver_handler))
507 receive_handler_cls = conn->receiver_handler_cls;
508 conn->receiver_handler = NULL;
509 receive_handler (receive_handler_cls, NULL);
514 /* FIXME: optimize for common fast case where buf contains the
515 entire message and we need no copying... */
518 /* slow path: append to array */
519 if (conn->received_size < conn->received_pos + available)
520 GNUNET_array_grow (conn->received_buf,
521 conn->received_size, conn->received_pos + available);
522 memcpy (&conn->received_buf[conn->received_pos], buf, available);
523 conn->received_pos += available;
524 check_complete (conn);
525 /* check for timeout */
526 remaining = GNUNET_TIME_absolute_get_remaining (conn->receive_timeout);
527 if (remaining.rel_value == 0)
529 /* signal timeout! */
530 if (NULL != conn->receiver_handler)
531 conn->receiver_handler (conn->receiver_handler_cls, NULL);
534 /* back to receive -- either for more data or to call callback! */
535 GNUNET_CLIENT_receive (conn,
536 conn->receiver_handler,
537 conn->receiver_handler_cls, remaining);
542 * Continuation to call the receive callback.
544 * @param cls our handle to the client connection
545 * @param tc scheduler context
548 receive_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
550 struct GNUNET_CLIENT_Connection *sock = cls;
551 GNUNET_CLIENT_MessageHandler handler = sock->receiver_handler;
552 const struct GNUNET_MessageHeader *cmsg =
553 (const struct GNUNET_MessageHeader *) sock->received_buf;
554 void *handler_cls = sock->receiver_handler_cls;
555 uint16_t msize = ntohs (cmsg->size);
557 struct GNUNET_MessageHeader *msg = (struct GNUNET_MessageHeader *) mbuf;
560 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
561 "Received message of type %u and size %u\n",
565 sock->receive_task = GNUNET_SCHEDULER_NO_TASK;
566 GNUNET_assert (GNUNET_YES == sock->msg_complete);
567 GNUNET_assert (sock->received_pos >= msize);
568 memcpy (msg, cmsg, msize);
569 memmove (sock->received_buf,
570 &sock->received_buf[msize], sock->received_pos - msize);
571 sock->received_pos -= msize;
572 sock->msg_complete = GNUNET_NO;
573 sock->receiver_handler = NULL;
574 check_complete (sock);
576 handler (handler_cls, msg);
581 * Read from the service.
583 * @param sock the service
584 * @param handler function to call with the message
585 * @param handler_cls closure for handler
586 * @param timeout how long to wait until timing out
589 GNUNET_CLIENT_receive (struct GNUNET_CLIENT_Connection *sock,
590 GNUNET_CLIENT_MessageHandler handler,
591 void *handler_cls, struct GNUNET_TIME_Relative timeout)
593 if (sock->sock == NULL)
595 /* already disconnected, fail instantly! */
596 GNUNET_break (0); /* this should not happen in well-written code! */
598 handler (handler_cls, NULL);
601 sock->receiver_handler = handler;
602 sock->receiver_handler_cls = handler_cls;
603 sock->receive_timeout = GNUNET_TIME_relative_to_absolute (timeout);
604 if (GNUNET_YES == sock->msg_complete)
606 GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == sock->receive_task);
607 sock->receive_task = GNUNET_SCHEDULER_add_now (&receive_task, sock);
611 GNUNET_assert (sock->in_receive == GNUNET_NO);
612 sock->in_receive = GNUNET_YES;
614 GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "calling GNUNET_CONNECTION_receive\n");
616 GNUNET_CONNECTION_receive (sock->sock,
617 GNUNET_SERVER_MAX_MESSAGE_SIZE - 1,
618 timeout, &receive_helper, sock);
624 * Report service unavailable.
627 service_test_error (GNUNET_SCHEDULER_Task task, void *task_cls)
629 GNUNET_SCHEDULER_add_continuation (task,
631 GNUNET_SCHEDULER_REASON_TIMEOUT);
636 * Receive confirmation from test, service is up.
639 * @param msg message received, NULL on timeout or fatal error
642 confirm_handler (void *cls, const struct GNUNET_MessageHeader *msg)
644 struct GNUNET_CLIENT_Connection *conn = cls;
645 /* We may want to consider looking at the reply in more
646 detail in the future, for example, is this the
647 correct service? FIXME! */
651 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
652 "Received confirmation that service is running.\n");
654 GNUNET_SCHEDULER_add_continuation (conn->test_cb,
656 GNUNET_SCHEDULER_REASON_PREREQ_DONE);
660 service_test_error (conn->test_cb, conn->test_cb_cls);
662 GNUNET_CLIENT_disconnect (conn, GNUNET_NO);
667 write_test (void *cls, size_t size, void *buf)
669 struct GNUNET_CLIENT_Connection *conn = cls;
670 struct GNUNET_MessageHeader *msg;
672 if (size < sizeof (struct GNUNET_MessageHeader))
675 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
676 _("Failure to transmit TEST request.\n"));
678 service_test_error (conn->test_cb, conn->test_cb_cls);
679 GNUNET_CLIENT_disconnect (conn, GNUNET_NO);
680 return 0; /* client disconnected */
683 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
684 "Transmitting `%s' request.\n", "TEST");
686 msg = (struct GNUNET_MessageHeader *) buf;
687 msg->type = htons (GNUNET_MESSAGE_TYPE_TEST);
688 msg->size = htons (sizeof (struct GNUNET_MessageHeader));
689 GNUNET_CLIENT_receive (conn,
692 GNUNET_TIME_absolute_get_remaining (conn->test_deadline));
693 return sizeof (struct GNUNET_MessageHeader);
698 * Wait until the service is running.
700 * @param service name of the service to wait for
701 * @param cfg configuration to use
702 * @param timeout how long to wait at most in ms
703 * @param task task to run if service is running
704 * (reason will be "PREREQ_DONE" (service running)
705 * or "TIMEOUT" (service not known to be running))
706 * @param task_cls closure for task
709 GNUNET_CLIENT_service_test (const char *service,
710 const struct GNUNET_CONFIGURATION_Handle *cfg,
711 struct GNUNET_TIME_Relative timeout,
712 GNUNET_SCHEDULER_Task task, void *task_cls)
714 struct GNUNET_CLIENT_Connection *conn;
717 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
718 "Testing if service `%s' is running.\n", service);
720 conn = GNUNET_CLIENT_connect (service, cfg);
723 GNUNET_log (GNUNET_ERROR_TYPE_INFO,
725 ("Could not connect to service `%s', must not be running.\n"),
727 service_test_error (task, task_cls);
730 conn->test_cb = task;
731 conn->test_cb_cls = task_cls;
732 conn->test_deadline = GNUNET_TIME_relative_to_absolute (timeout);
734 if (NULL == GNUNET_CLIENT_notify_transmit_ready (conn,
735 sizeof (struct GNUNET_MessageHeader),
740 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
741 _("Failure to transmit request to service `%s'\n"),
743 service_test_error (task, task_cls);
744 GNUNET_CLIENT_disconnect (conn, GNUNET_NO);
751 * Connection notifies us about failure or success of
752 * a transmission request. Either pass it on to our
753 * user or, if possible, retry.
755 * @param cls our "struct GNUNET_CLIENT_TransmissionHandle"
756 * @param size number of bytes available for transmission
757 * @param buf where to write them
758 * @return number of bytes written to buf
760 static size_t client_notify (void *cls, size_t size, void *buf);
764 * This task is run if we should re-try connection to the
765 * service after a while.
767 * @param cls our "struct GNUNET_CLIENT_TransmitHandle" of the request
771 client_delayed_retry (void *cls,
772 const struct GNUNET_SCHEDULER_TaskContext *tc)
774 struct GNUNET_CLIENT_TransmitHandle *th = cls;
775 struct GNUNET_TIME_Relative delay;
777 th->reconnect_task = GNUNET_SCHEDULER_NO_TASK;
778 if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
781 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
782 "Transmission failed due to shutdown.\n");
785 th->notify (th->notify_cls, 0, NULL);
789 th->sock->sock = do_connect (th->sock->service_name,
791 th->sock->attempts++);
792 if (NULL == th->sock->sock)
794 /* could happen if we're out of sockets */
795 delay = GNUNET_TIME_relative_min (GNUNET_TIME_absolute_get_remaining (th->timeout),
798 = GNUNET_TIME_relative_min (GNUNET_TIME_relative_multiply (th->sock->back_off, 2),
799 GNUNET_TIME_UNIT_SECONDS);
801 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
802 "Transmission failed %u times, trying again in %llums.\n",
803 MAX_ATTEMPTS - th->attempts_left,
804 (unsigned long long) delay.rel_value);
806 th->reconnect_task = GNUNET_SCHEDULER_add_delayed (delay,
807 &client_delayed_retry,
811 GNUNET_CONNECTION_ignore_shutdown (th->sock->sock,
812 th->sock->ignore_shutdown);
813 th->th = GNUNET_CONNECTION_notify_transmit_ready (th->sock->sock,
815 GNUNET_TIME_absolute_get_remaining
821 th->notify (th->notify_cls, 0, NULL);
829 * Connection notifies us about failure or success of a transmission
830 * request. Either pass it on to our user or, if possible, retry.
832 * @param cls our "struct GNUNET_CLIENT_TransmissionHandle"
833 * @param size number of bytes available for transmission
834 * @param buf where to write them
835 * @return number of bytes written to buf
838 client_notify (void *cls, size_t size, void *buf)
840 struct GNUNET_CLIENT_TransmitHandle *th = cls;
842 struct GNUNET_TIME_Relative delay;
848 delay = GNUNET_TIME_absolute_get_remaining (th->timeout);
849 delay.rel_value /= 2;
850 if ( (0 != (GNUNET_SCHEDULER_REASON_SHUTDOWN & GNUNET_SCHEDULER_get_reason ())) ||
851 (GNUNET_YES != th->auto_retry) ||
852 (0 == --th->attempts_left) ||
853 (delay.rel_value < 1) )
856 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
857 "Transmission failed %u times, giving up.\n",
858 MAX_ATTEMPTS - th->attempts_left);
860 GNUNET_break (0 == th->notify (th->notify_cls, 0, NULL));
866 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
867 "Failed to connect to `%s', automatically trying again.\n",
868 th->sock->service_name);
870 GNUNET_CONNECTION_destroy (th->sock->sock, GNUNET_NO);
871 th->sock->sock = NULL;
872 delay = GNUNET_TIME_relative_min (delay, th->sock->back_off);
874 = GNUNET_TIME_relative_min (GNUNET_TIME_relative_multiply (th->sock->back_off, 2),
875 GNUNET_TIME_UNIT_SECONDS);
877 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
878 "Transmission failed %u times, trying again in %llums.\n",
879 MAX_ATTEMPTS - th->attempts_left,
880 (unsigned long long) delay.rel_value);
882 th->reconnect_task = GNUNET_SCHEDULER_add_delayed (delay,
883 &client_delayed_retry,
888 GNUNET_assert (size >= th->size);
889 ret = th->notify (th->notify_cls, size, buf);
896 * Ask the client to call us once the specified number of bytes
897 * are free in the transmission buffer. May call the notify
898 * method immediately if enough space is available.
900 * @param sock connection to the service
901 * @param size number of bytes to send
902 * @param timeout after how long should we give up (and call
903 * notify with buf NULL and size 0)?
904 * @param auto_retry if the connection to the service dies, should we
905 * automatically re-connect and retry (within the timeout period)
906 * or should we immediately fail in this case? Pass GNUNET_YES
907 * if the caller does not care about temporary connection errors,
908 * for example because the protocol is stateless
909 * @param notify function to call
910 * @param notify_cls closure for notify
911 * @return NULL if our buffer will never hold size bytes,
912 * a handle if the notify callback was queued (can be used to cancel)
914 struct GNUNET_CLIENT_TransmitHandle *
915 GNUNET_CLIENT_notify_transmit_ready (struct GNUNET_CLIENT_Connection *sock,
917 struct GNUNET_TIME_Relative timeout,
919 GNUNET_CONNECTION_TransmitReadyNotify
920 notify, void *notify_cls)
922 struct GNUNET_CLIENT_TransmitHandle *th;
924 if (NULL != sock->th)
926 /* If this breaks, you most likley called this function twice without waiting
927 * for completion or canceling the request */
931 th = GNUNET_malloc (sizeof (struct GNUNET_CLIENT_TransmitHandle));
934 th->timeout = GNUNET_TIME_relative_to_absolute (timeout);
935 th->auto_retry = auto_retry;
937 th->notify_cls = notify_cls;
938 th->attempts_left = MAX_ATTEMPTS;
939 if (sock->sock == NULL)
941 th->reconnect_task = GNUNET_SCHEDULER_add_delayed (sock->back_off,
942 &client_delayed_retry,
948 th->th = GNUNET_CONNECTION_notify_transmit_ready (sock->sock,
965 * Cancel a request for notification.
967 * @param th handle from the original request.
970 GNUNET_CLIENT_notify_transmit_ready_cancel (struct
971 GNUNET_CLIENT_TransmitHandle *th)
973 if (th->reconnect_task != GNUNET_SCHEDULER_NO_TASK)
975 GNUNET_break (NULL == th->th);
976 GNUNET_SCHEDULER_cancel (th->reconnect_task);
977 th->reconnect_task = GNUNET_SCHEDULER_NO_TASK;
981 GNUNET_assert (NULL != th->th);
982 GNUNET_CONNECTION_notify_transmit_ready_cancel (th->th);
990 * Function called to notify a client about the socket
991 * begin ready to queue the message. "buf" will be
992 * NULL and "size" zero if the socket was closed for
993 * writing in the meantime.
995 * @param cls closure of type "struct TransmitGetResponseContext*"
996 * @param size number of bytes available in buf
997 * @param buf where the callee should write the message
998 * @return number of bytes written to buf
1001 transmit_for_response (void *cls, size_t size, void *buf)
1003 struct TransmitGetResponseContext *tc = cls;
1006 tc->sock->tag = NULL;
1007 msize = ntohs (tc->hdr->size);
1011 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
1012 _("Could not submit request, not expecting to receive a response.\n"));
1015 tc->rn (tc->rn_cls, NULL);
1019 GNUNET_assert (size >= msize);
1020 memcpy (buf, tc->hdr, msize);
1021 GNUNET_CLIENT_receive (tc->sock,
1024 GNUNET_TIME_absolute_get_remaining (tc->timeout));
1031 * Convenience API that combines sending a request
1032 * to the service and waiting for a response.
1033 * If either operation times out, the callback
1034 * will be called with a "NULL" response (in which
1035 * case the connection should probably be destroyed).
1037 * @param sock connection to use
1038 * @param hdr message to transmit
1039 * @param timeout when to give up (for both transmission
1040 * and for waiting for a response)
1041 * @param auto_retry if the connection to the service dies, should we
1042 * automatically re-connect and retry (within the timeout period)
1043 * or should we immediately fail in this case? Pass GNUNET_YES
1044 * if the caller does not care about temporary connection errors,
1045 * for example because the protocol is stateless
1046 * @param rn function to call with the response
1047 * @param rn_cls closure for rn
1048 * @return GNUNET_OK on success, GNUNET_SYSERR if a request
1049 * is already pending
1052 GNUNET_CLIENT_transmit_and_get_response (struct GNUNET_CLIENT_Connection
1054 const struct GNUNET_MessageHeader
1056 struct GNUNET_TIME_Relative timeout,
1058 GNUNET_CLIENT_MessageHandler rn,
1061 struct TransmitGetResponseContext *tc;
1064 if (NULL != sock->th)
1065 return GNUNET_SYSERR;
1066 GNUNET_assert (sock->tag == NULL);
1067 msize = ntohs (hdr->size);
1068 tc = GNUNET_malloc (sizeof (struct TransmitGetResponseContext) + msize);
1070 tc->hdr = (const struct GNUNET_MessageHeader *) &tc[1];
1071 memcpy (&tc[1], hdr, msize);
1072 tc->timeout = GNUNET_TIME_relative_to_absolute (timeout);
1074 tc->rn_cls = rn_cls;
1075 if (NULL == GNUNET_CLIENT_notify_transmit_ready (sock,
1079 &transmit_for_response,
1084 return GNUNET_SYSERR;
1092 /* end of client.c */