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 * Struct to refer to a GNUnet TCP connection.
41 * This is more than just a socket because if the server
42 * drops the connection, the client automatically tries
43 * to reconnect (and for that needs connection information).
45 struct GNUNET_CLIENT_Connection
49 * the socket handle, NULL if not live
51 struct GNUNET_CONNECTION_Handle *sock;
56 struct GNUNET_SCHEDULER_Handle *sched;
59 * Name of the service we interact with.
64 * ID of task used for receiving.
66 GNUNET_SCHEDULER_TaskIdentifier receiver_task;
69 * Handler for current receiver task.
71 GNUNET_CLIENT_MessageHandler receiver_handler;
74 * Closure for receiver_handler.
76 void *receiver_handler_cls;
79 * Handler for service test completion (NULL unless in service_test)
81 GNUNET_SCHEDULER_Task test_cb;
84 * Closure for test_cb (NULL unless in service_test)
89 * Buffer for received message.
94 * Timeout for receiving a response (absolute time).
96 struct GNUNET_TIME_Absolute receive_timeout;
99 * Number of bytes in received_buf that are valid.
104 * Size of received_buf.
106 unsigned int received_size;
109 * Do we have a complete response in received_buf?
117 * Get a connection with a service.
119 * @param sched scheduler to use
120 * @param service_name name of the service
121 * @param cfg configuration to use
122 * @return NULL on error (service unknown to configuration)
124 struct GNUNET_CLIENT_Connection *
125 GNUNET_CLIENT_connect (struct GNUNET_SCHEDULER_Handle *sched,
126 const char *service_name,
127 const struct GNUNET_CONFIGURATION_Handle *cfg)
129 struct GNUNET_CLIENT_Connection *ret;
130 struct GNUNET_CONNECTION_Handle *sock;
132 unsigned long long port;
135 GNUNET_CONFIGURATION_get_value_number (cfg,
141 GNUNET_CONFIGURATION_get_value_string (cfg,
143 "HOSTNAME", &hostname)))
145 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
146 "Could not determine valid hostname and port for service `%s' from configuration.\n",
150 sock = GNUNET_CONNECTION_create_from_connect (sched,
153 GNUNET_SERVER_MAX_MESSAGE_SIZE);
154 GNUNET_free (hostname);
157 ret = GNUNET_malloc (sizeof (struct GNUNET_CLIENT_Connection));
160 ret->service_name = GNUNET_strdup (service_name);
166 * Receiver task has completed, free rest of client
170 finish_cleanup (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
172 struct GNUNET_CLIENT_Connection *sock = cls;
174 GNUNET_array_grow (sock->received_buf, sock->received_size, 0);
175 GNUNET_free (sock->service_name);
181 * Destroy connection with the service.
184 GNUNET_CLIENT_disconnect (struct GNUNET_CLIENT_Connection *sock)
186 GNUNET_assert (sock->sock != NULL);
187 GNUNET_CONNECTION_destroy (sock->sock);
189 sock->receiver_handler = NULL;
190 GNUNET_SCHEDULER_add_after (sock->sched,
192 GNUNET_SCHEDULER_PRIORITY_KEEP,
193 sock->receiver_task, &finish_cleanup, sock);
198 * check if message is complete
201 check_complete (struct GNUNET_CLIENT_Connection *conn)
203 if ((conn->received_pos >= sizeof (struct GNUNET_MessageHeader)) &&
204 (conn->received_pos >=
205 ntohs (((const struct GNUNET_MessageHeader *) conn->
206 received_buf)->size)))
207 conn->msg_complete = GNUNET_YES;
212 * Callback function for data received from the network. Note that
213 * both "available" and "errCode" would be 0 if the read simply timed out.
216 * @param buf pointer to received data
217 * @param available number of bytes availabe in "buf",
218 * possibly 0 (on errors)
219 * @param addr address of the sender
220 * @param addrlen size of addr
221 * @param errCode value of errno (on errors receiving)
224 receive_helper (void *cls,
227 const struct sockaddr *addr, socklen_t addrlen, int errCode)
229 struct GNUNET_CLIENT_Connection *conn = cls;
230 struct GNUNET_TIME_Relative remaining;
232 GNUNET_assert (conn->msg_complete == GNUNET_NO);
233 conn->receiver_task = GNUNET_SCHEDULER_NO_TASK;
235 if ((available == 0) || (conn->sock == NULL) || (errCode != 0))
237 /* signal timeout! */
238 if (conn->receiver_handler != NULL)
240 conn->receiver_handler (conn->receiver_handler_cls, NULL);
241 conn->receiver_handler = NULL;
246 /* FIXME: optimize for common fast case where buf contains the
247 entire message and we need no copying... */
250 /* slow path: append to array */
251 if (conn->received_size < conn->received_pos + available)
252 GNUNET_array_grow (conn->received_buf,
253 conn->received_size, conn->received_pos + available);
254 memcpy (&conn->received_buf[conn->received_pos], buf, available);
255 conn->received_pos += available;
256 check_complete (conn);
257 /* check for timeout */
258 remaining = GNUNET_TIME_absolute_get_remaining (conn->receive_timeout);
259 if (remaining.value == 0)
261 /* signal timeout! */
262 conn->receiver_handler (conn->receiver_handler_cls, NULL);
265 /* back to receive -- either for more data or to call callback! */
266 GNUNET_CLIENT_receive (conn,
267 conn->receiver_handler,
268 conn->receiver_handler_cls, remaining);
273 * Continuation to call the receive callback.
276 receive_task (void *scls, const struct GNUNET_SCHEDULER_TaskContext *tc)
278 struct GNUNET_CLIENT_Connection *sock = scls;
279 GNUNET_CLIENT_MessageHandler handler = sock->receiver_handler;
280 const struct GNUNET_MessageHeader *cmsg = (const struct GNUNET_MessageHeader *) sock->received_buf;
281 void *cls = sock->receiver_handler_cls;
282 uint16_t msize = ntohs (cmsg->size);
284 struct GNUNET_MessageHeader *msg = (struct GNUNET_MessageHeader*) mbuf;
286 GNUNET_assert (GNUNET_YES == sock->msg_complete);
287 sock->receiver_task = GNUNET_SCHEDULER_NO_TASK;
288 GNUNET_assert (sock->received_pos >= msize);
289 memcpy (msg, cmsg, msize);
290 memmove (sock->received_buf,
291 &sock->received_buf[msize], sock->received_pos - msize);
292 sock->received_pos -= msize;
293 sock->msg_complete = GNUNET_NO;
294 sock->receiver_handler = NULL;
295 check_complete (sock);
302 * Read from the service.
304 * @param sock the service
305 * @param handler function to call with the message
306 * @param handler_cls closure for handler
307 * @param timeout how long to wait until timing out
310 GNUNET_CLIENT_receive (struct GNUNET_CLIENT_Connection *sock,
311 GNUNET_CLIENT_MessageHandler handler,
312 void *handler_cls, struct GNUNET_TIME_Relative timeout)
314 if (sock->sock == NULL)
316 /* already disconnected, fail instantly! */
317 GNUNET_break (0); /* this should not happen in well-written code! */
318 handler (handler_cls, NULL);
321 GNUNET_assert (sock->receiver_task ==
322 GNUNET_SCHEDULER_NO_TASK);
323 sock->receiver_handler = handler;
324 sock->receiver_handler_cls = handler_cls;
325 sock->receive_timeout = GNUNET_TIME_relative_to_absolute (timeout);
326 if (GNUNET_YES == sock->msg_complete)
327 sock->receiver_task = GNUNET_SCHEDULER_add_after (sock->sched,
329 GNUNET_SCHEDULER_PRIORITY_KEEP,
330 GNUNET_SCHEDULER_NO_TASK,
331 &receive_task, sock);
333 sock->receiver_task = GNUNET_CONNECTION_receive (sock->sock,
334 GNUNET_SERVER_MAX_MESSAGE_SIZE,
336 &receive_helper, sock);
341 write_shutdown (void *cls, size_t size, void *buf)
343 struct GNUNET_MessageHeader *msg;
345 if (size < sizeof (struct GNUNET_MessageHeader))
346 return 0; /* client disconnected */
347 msg = (struct GNUNET_MessageHeader *) buf;
348 msg->type = htons (GNUNET_MESSAGE_TYPE_SHUTDOWN);
349 msg->size = htons (sizeof (struct GNUNET_MessageHeader));
350 return sizeof (struct GNUNET_MessageHeader);
355 * Request that the service should shutdown.
356 * Afterwards, the connection should be disconnected.
358 * @param sock the socket connected to the service
361 GNUNET_CLIENT_service_shutdown (struct GNUNET_CLIENT_Connection *sock)
363 GNUNET_CONNECTION_notify_transmit_ready (sock->sock,
364 sizeof (struct GNUNET_MessageHeader),
365 GNUNET_TIME_UNIT_FOREVER_REL,
366 &write_shutdown, NULL);
371 * Report service unavailable.
374 service_test_error (struct GNUNET_SCHEDULER_Handle *s,
375 GNUNET_SCHEDULER_Task task, void *task_cls)
377 GNUNET_SCHEDULER_add_continuation (s,
381 GNUNET_SCHEDULER_REASON_TIMEOUT);
386 * Receive confirmation from test, service is up.
389 * @param msg message received, NULL on timeout or fatal error
392 confirm_handler (void *cls, const struct GNUNET_MessageHeader *msg)
394 struct GNUNET_CLIENT_Connection *conn = cls;
395 /* We may want to consider looking at the reply in more
396 detail in the future, for example, is this the
397 correct service? FIXME! */
401 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
402 "Received confirmation that service is running.\n");
404 GNUNET_SCHEDULER_add_continuation (conn->sched,
408 GNUNET_SCHEDULER_REASON_PREREQ_DONE);
412 service_test_error (conn->sched, conn->test_cb, conn->test_cb_cls);
414 GNUNET_CLIENT_disconnect (conn);
419 write_test (void *cls, size_t size, void *buf)
421 struct GNUNET_MessageHeader *msg;
423 if (size < sizeof (struct GNUNET_MessageHeader))
426 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
427 _("Failure to transmit TEST request.\n"));
429 return 0; /* client disconnected */
432 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, _("Transmitting TEST request.\n"));
434 msg = (struct GNUNET_MessageHeader *) buf;
435 msg->type = htons (GNUNET_MESSAGE_TYPE_TEST);
436 msg->size = htons (sizeof (struct GNUNET_MessageHeader));
437 return sizeof (struct GNUNET_MessageHeader);
442 * Wait until the service is running.
444 * @param sched scheduler to use
445 * @param service name of the service to wait for
446 * @param cfg configuration to use
447 * @param timeout how long to wait at most in ms
448 * @param task task to run if service is running
449 * (reason will be "PREREQ_DONE" (service running)
450 * or "TIMEOUT" (service not known to be running))
451 * @param task_cls closure for task
454 GNUNET_CLIENT_service_test (struct GNUNET_SCHEDULER_Handle *sched,
456 const struct GNUNET_CONFIGURATION_Handle *cfg,
457 struct GNUNET_TIME_Relative timeout,
458 GNUNET_SCHEDULER_Task task, void *task_cls)
460 struct GNUNET_CLIENT_Connection *conn;
463 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
464 "Testing if service `%s' is running.\n", service);
466 conn = GNUNET_CLIENT_connect (sched, service, cfg);
469 GNUNET_log (GNUNET_ERROR_TYPE_INFO,
471 ("Could not connect to service `%s', must not be running.\n"),
473 service_test_error (sched, task, task_cls);
476 conn->test_cb = task;
477 conn->test_cb_cls = task_cls;
479 GNUNET_CONNECTION_notify_transmit_ready (conn->sock,
481 GNUNET_MessageHeader),
482 timeout, &write_test, NULL))
484 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
485 _("Failure to transmit request to service `%s'\n"),
487 service_test_error (sched, task, task_cls);
488 GNUNET_CLIENT_disconnect (conn);
491 GNUNET_CLIENT_receive (conn, &confirm_handler, conn, timeout);
496 * Ask the client to call us once the specified number of bytes
497 * are free in the transmission buffer. May call the notify
498 * method immediately if enough space is available.
500 * @param sock connection to the service
501 * @param size number of bytes to send
502 * @param timeout after how long should we give up (and call
503 * notify with buf NULL and size 0)?
504 * @param notify function to call
505 * @param notify_cls closure for notify
506 * @return NULL if our buffer will never hold size bytes,
507 * a handle if the notify callback was queued (can be used to cancel)
509 struct GNUNET_CONNECTION_TransmitHandle *
510 GNUNET_CLIENT_notify_transmit_ready (struct GNUNET_CLIENT_Connection *sock,
512 struct GNUNET_TIME_Relative timeout,
513 GNUNET_CONNECTION_TransmitReadyNotify
514 notify, void *notify_cls)
516 return GNUNET_CONNECTION_notify_transmit_ready (sock->sock,
518 timeout, notify, notify_cls);
523 * Context for processing
524 * "GNUNET_CLIENT_transmit_and_get_response" requests.
531 struct GNUNET_CLIENT_Connection *sock;
534 * Message to transmit; do not free, allocated
535 * right after this struct.
537 const struct GNUNET_MessageHeader *hdr;
542 struct GNUNET_TIME_Absolute timeout;
545 * Function to call when done.
547 GNUNET_CLIENT_MessageHandler rn;
557 * Function called to notify a client about the socket
558 * begin ready to queue the message. "buf" will be
559 * NULL and "size" zero if the socket was closed for
560 * writing in the meantime.
562 * @param cls closure of type "struct TARCtx*"
563 * @param size number of bytes available in buf
564 * @param buf where the callee should write the message
565 * @return number of bytes written to buf
568 transmit_for_response (void *cls,
572 struct TARCtx *tc = cls;
575 msize = ntohs(tc->hdr->size);
578 tc->rn (tc->rn_cls, NULL);
582 GNUNET_assert (size >= msize);
583 memcpy (buf, tc->hdr, msize);
584 GNUNET_CLIENT_receive (tc->sock,
587 GNUNET_TIME_absolute_get_remaining (tc->timeout));
594 * Convenience API that combines sending a request
595 * to the service and waiting for a response.
596 * If either operation times out, the callback
597 * will be called with a "NULL" response (in which
598 * case the connection should probably be destroyed).
600 * @param sock connection to use
601 * @param hdr message to transmit
602 * @param timeout when to give up (for both transmission
603 * and for waiting for a response)
604 * @param rn function to call with the response
605 * @param rn_cls closure for rn
608 GNUNET_CLIENT_transmit_and_get_response (struct GNUNET_CLIENT_Connection *sock,
609 const struct GNUNET_MessageHeader *hdr,
610 struct GNUNET_TIME_Relative timeout,
611 GNUNET_CLIENT_MessageHandler rn,
617 msize = ntohs(hdr->size);
618 tc = GNUNET_malloc(sizeof (struct TARCtx) + msize);
620 tc->hdr = (const struct GNUNET_MessageHeader*) &tc[1];
621 memcpy (&tc[1], hdr, msize);
622 tc->timeout = GNUNET_TIME_relative_to_absolute (timeout);
625 GNUNET_CLIENT_notify_transmit_ready (sock,
628 &transmit_for_response,
634 /* end of client.c */