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22 * @file transport/transport_api_core.c
23 * @brief library to access the transport service for message exchange
24 * @author Christian Grothoff
27 #include "gnunet_util_lib.h"
28 #include "gnunet_constants.h"
29 #include "gnunet_arm_service.h"
30 #include "gnunet_hello_lib.h"
31 #include "gnunet_protocols.h"
32 #include "gnunet_transport_core_service.h"
33 #include "transport.h"
35 #define LOG(kind, ...) GNUNET_log_from(kind, "transport-api-core", __VA_ARGS__)
38 * How large to start with for the hashmap of neighbours.
40 #define STARTING_NEIGHBOURS_SIZE 16
43 * Window size. How many messages to the same target do we pass
44 * to TRANSPORT without a SEND_OK in between? Small values limit
45 * thoughput, large values will increase latency.
47 * FIXME-OPTIMIZE: find out what good values are experimentally,
48 * maybe set adaptively (i.e. to observed available bandwidth).
50 #define SEND_WINDOW_SIZE 4
54 * Entry in hash table of all of our current (connected) neighbours.
58 * Identity of this neighbour.
60 struct GNUNET_PeerIdentity id;
63 * Overall transport handle.
65 struct GNUNET_TRANSPORT_CoreHandle *h;
68 * Active message queue for the peer.
70 struct GNUNET_MQ_Handle *mq;
73 * Envelope with the message we are currently transmitting (or NULL).
75 struct GNUNET_MQ_Envelope *env;
78 * Closure for @e mq handlers.
83 * How many messages can we still send to this peer before we should
86 unsigned int ready_window;
89 * Used to indicate our status if @e env is non-NULL. Set to
90 * #GNUNET_YES if we did pass a message to the MQ and are waiting
91 * for the call to #notify_send_done(). Set to #GNUNET_NO if the @e
92 * ready_window is 0 and @e env is waiting for a
93 * #GNUNET_MESSAGE_TYPE_TRANSPORT_RECV_OK?
95 int16_t awaiting_done;
98 * Size of the message in @e env.
105 * Handle for the transport service (includes all of the
106 * state for the transport service).
108 struct GNUNET_TRANSPORT_CoreHandle {
110 * Closure for the callbacks.
115 * Functions to call for received data (template for
116 * new message queues).
118 struct GNUNET_MQ_MessageHandler *handlers;
121 * function to call on connect events
123 GNUNET_TRANSPORT_NotifyConnect nc_cb;
126 * function to call on disconnect events
128 GNUNET_TRANSPORT_NotifyDisconnect nd_cb;
131 * My client connection to the transport service.
133 struct GNUNET_MQ_Handle *mq;
138 const struct GNUNET_CONFIGURATION_Handle *cfg;
141 * Hash map of the current connected neighbours of this peer.
142 * Maps peer identities to `struct Neighbour` entries.
144 struct GNUNET_CONTAINER_MultiPeerMap *neighbours;
147 * Peer identity as assumed by this process, or all zeros.
149 struct GNUNET_PeerIdentity self;
152 * ID of the task trying to reconnect to the service.
154 struct GNUNET_SCHEDULER_Task *reconnect_task;
157 * Delay until we try to reconnect.
159 struct GNUNET_TIME_Relative reconnect_delay;
162 * Should we check that @e self matches what the service thinks?
163 * (if #GNUNET_NO, then @e self is all zeros!).
170 * Function that will schedule the job that will try
171 * to connect us again to the client.
173 * @param h transport service to reconnect
176 disconnect_and_schedule_reconnect(struct GNUNET_TRANSPORT_CoreHandle *h);
180 * Get the neighbour list entry for the given peer
182 * @param h our context
183 * @param peer peer to look up
184 * @return NULL if no such peer entry exists
186 static struct Neighbour *
187 neighbour_find(struct GNUNET_TRANSPORT_CoreHandle *h,
188 const struct GNUNET_PeerIdentity *peer)
190 return GNUNET_CONTAINER_multipeermap_get(h->neighbours, peer);
195 * Iterator over hash map entries, for deleting state of a neighbour.
197 * @param cls the `struct GNUNET_TRANSPORT_CoreHandle *`
198 * @param key peer identity
199 * @param value value in the hash map, the neighbour entry to delete
200 * @return #GNUNET_YES if we should continue to
205 neighbour_delete(void *cls, const struct GNUNET_PeerIdentity *key, void *value)
207 struct GNUNET_TRANSPORT_CoreHandle *handle = cls;
208 struct Neighbour *n = value;
210 LOG(GNUNET_ERROR_TYPE_DEBUG,
211 "Dropping entry for neighbour `%s'.\n",
213 if (NULL != handle->nd_cb)
214 handle->nd_cb(handle->cls, &n->id, n->handlers_cls);
217 GNUNET_MQ_send_cancel(n->env);
220 GNUNET_MQ_destroy(n->mq);
221 GNUNET_assert(NULL == n->mq);
224 GNUNET_CONTAINER_multipeermap_remove(handle->neighbours, key, n));
231 * Generic error handler, called with the appropriate
232 * error code and the same closure specified at the creation of
234 * Not every message queue implementation supports an error handler.
236 * @param cls closure with the `struct GNUNET_TRANSPORT_CoreHandle *`
237 * @param error error code
240 mq_error_handler(void *cls, enum GNUNET_MQ_Error error)
242 struct GNUNET_TRANSPORT_CoreHandle *h = cls;
244 LOG(GNUNET_ERROR_TYPE_DEBUG,
245 "Error receiving from transport service, disconnecting temporarily.\n");
246 disconnect_and_schedule_reconnect(h);
251 * A message from the handler's message queue to a neighbour was
252 * transmitted. Now trigger (possibly delayed) notification of the
253 * neighbour's message queue that we are done and thus ready for
254 * the next message. Note that the MQ being ready is independent
255 * of the send window, as we may queue many messages and simply
256 * not pass them to TRANSPORT if the send window is insufficient.
258 * @param cls the `struct Neighbour` where the message was sent
261 notify_send_done(void *cls)
263 struct Neighbour *n = cls;
265 n->awaiting_done = GNUNET_NO;
267 GNUNET_MQ_impl_send_continue(n->mq);
272 * We have an envelope waiting for transmission at @a n, and
273 * our transmission window is positive. Perform the transmission.
275 * @param n neighbour to perform transmission for
278 do_send(struct Neighbour *n)
280 GNUNET_assert(0 < n->ready_window);
281 GNUNET_assert(NULL != n->env);
283 n->awaiting_done = GNUNET_YES;
284 GNUNET_MQ_notify_sent(n->env, ¬ify_send_done, n);
285 GNUNET_MQ_send(n->h->mq, n->env);
286 LOG(GNUNET_ERROR_TYPE_DEBUG,
287 "Passed message of type %u for neighbour `%s' to TRANSPORT.\n",
288 ntohs(GNUNET_MQ_env_get_msg(n->env)->type),
294 * Implement sending functionality of a message queue.
295 * Called one message at a time. Should send the @a msg
296 * to the transport service and then notify the queue
297 * once we are ready for the next one.
299 * @param mq the message queue
300 * @param msg the message to send
301 * @param impl_state state of the implementation
304 mq_send_impl(struct GNUNET_MQ_Handle *mq,
305 const struct GNUNET_MessageHeader *msg,
308 struct Neighbour *n = impl_state;
309 struct OutboundMessage *obm;
312 msize = ntohs(msg->size);
313 if (msize >= GNUNET_MAX_MESSAGE_SIZE - sizeof(*obm))
316 GNUNET_MQ_impl_send_continue(mq);
319 LOG(GNUNET_ERROR_TYPE_DEBUG,
320 "CORE requested transmission of message of type %u to neighbour `%s'.\n",
324 GNUNET_assert(NULL == n->env);
326 GNUNET_MQ_msg_nested_mh(obm, GNUNET_MESSAGE_TYPE_TRANSPORT_SEND, msg);
327 n->env_size = ntohs(msg->size);
329 struct GNUNET_MQ_Envelope *env;
331 env = GNUNET_MQ_get_current_envelope(mq);
332 obm->priority = htonl((uint32_t)GNUNET_MQ_env_get_options(env));
335 if (0 == n->ready_window)
337 LOG(GNUNET_ERROR_TYPE_DEBUG,
338 "Flow control delays transmission to CORE until we see SEND_OK.\n");
339 return; /* can't send yet, need to wait for SEND_OK */
346 * Handle destruction of a message queue. Implementations must not
347 * free @a mq, but should take care of @a impl_state.
349 * @param mq the message queue to destroy
350 * @param impl_state state of the implementation
353 mq_destroy_impl(struct GNUNET_MQ_Handle *mq, void *impl_state)
355 struct Neighbour *n = impl_state;
357 GNUNET_assert(mq == n->mq);
363 * Implementation function that cancels the currently sent message.
364 * Should basically undo whatever #mq_send_impl() did.
366 * @param mq message queue
367 * @param impl_state state specific to the implementation
370 mq_cancel_impl(struct GNUNET_MQ_Handle *mq, void *impl_state)
372 struct Neighbour *n = impl_state;
375 if (GNUNET_YES == n->awaiting_done)
377 GNUNET_MQ_send_cancel(n->env);
379 n->awaiting_done = GNUNET_NO;
383 GNUNET_assert(0 == n->ready_window);
390 * We had an error processing a message we forwarded from a peer to
391 * the CORE service. We should just complain about it but otherwise
392 * continue processing.
395 * @param error error code
398 peer_mq_error_handler(void *cls, enum GNUNET_MQ_Error error)
400 /* struct Neighbour *n = cls; */
407 * Function we use for handling incoming connect messages.
409 * @param cls closure, a `struct GNUNET_TRANSPORT_Handle *`
410 * @param cim message received
413 handle_connect(void *cls, const struct ConnectInfoMessage *cim)
415 struct GNUNET_TRANSPORT_CoreHandle *h = cls;
418 LOG(GNUNET_ERROR_TYPE_DEBUG,
419 "Receiving CONNECT message for `%s'\n",
420 GNUNET_i2s(&cim->id));
421 n = neighbour_find(h, &cim->id);
425 disconnect_and_schedule_reconnect(h);
428 n = GNUNET_new(struct Neighbour);
431 n->ready_window = SEND_WINDOW_SIZE;
432 GNUNET_assert(GNUNET_OK ==
433 GNUNET_CONTAINER_multipeermap_put(
437 GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
439 n->mq = GNUNET_MQ_queue_for_callbacks(&mq_send_impl,
444 &peer_mq_error_handler,
446 if (NULL != h->nc_cb)
448 n->handlers_cls = h->nc_cb(h->cls, &n->id, n->mq);
449 GNUNET_MQ_set_handlers_closure(n->mq, n->handlers_cls);
455 * Function we use for handling incoming disconnect messages.
457 * @param cls closure, a `struct GNUNET_TRANSPORT_CoreHandle *`
458 * @param dim message received
461 handle_disconnect(void *cls, const struct DisconnectInfoMessage *dim)
463 struct GNUNET_TRANSPORT_CoreHandle *h = cls;
466 GNUNET_break(ntohl(dim->reserved) == 0);
467 LOG(GNUNET_ERROR_TYPE_DEBUG,
468 "Receiving DISCONNECT message for `%s'.\n",
469 GNUNET_i2s(&dim->peer));
470 n = neighbour_find(h, &dim->peer);
474 disconnect_and_schedule_reconnect(h);
477 GNUNET_assert(GNUNET_YES == neighbour_delete(h, &dim->peer, n));
482 * Function we use for handling incoming send-ok messages.
484 * @param cls closure, a `struct GNUNET_TRANSPORT_CoreHandle *`
485 * @param okm message received
488 handle_send_ok(void *cls, const struct SendOkMessage *okm)
490 struct GNUNET_TRANSPORT_CoreHandle *h = cls;
493 LOG(GNUNET_ERROR_TYPE_DEBUG,
494 "Receiving SEND_OK message for transmission to %s\n",
495 GNUNET_i2s(&okm->peer));
496 n = neighbour_find(h, &okm->peer);
499 /* We should never get a 'SEND_OK' for a peer that we are not
502 disconnect_and_schedule_reconnect(h);
506 if ((NULL != n->env) && (1 == n->ready_window))
512 * Function we use for checking incoming "inbound" messages.
514 * @param cls closure, a `struct GNUNET_TRANSPORT_CoreHandle *`
515 * @param im message received
518 check_recv(void *cls, const struct InboundMessage *im)
520 const struct GNUNET_MessageHeader *imm;
523 size = ntohs(im->header.size) - sizeof(*im);
524 if (size < sizeof(struct GNUNET_MessageHeader))
527 return GNUNET_SYSERR;
529 imm = (const struct GNUNET_MessageHeader *)&im[1];
530 if (ntohs(imm->size) != size)
533 return GNUNET_SYSERR;
540 * Function we use for handling incoming messages.
542 * @param cls closure, a `struct GNUNET_TRANSPORT_CoreHandle *`
543 * @param im message received
546 handle_recv(void *cls, const struct InboundMessage *im)
548 struct GNUNET_TRANSPORT_CoreHandle *h = cls;
549 const struct GNUNET_MessageHeader *imm =
550 (const struct GNUNET_MessageHeader *)&im[1];
553 LOG(GNUNET_ERROR_TYPE_DEBUG,
554 "Received message of type %u with %u bytes from `%s'.\n",
555 (unsigned int)ntohs(imm->type),
556 (unsigned int)ntohs(imm->size),
557 GNUNET_i2s(&im->peer));
558 n = neighbour_find(h, &im->peer);
562 disconnect_and_schedule_reconnect(h);
565 GNUNET_MQ_inject_message(n->mq, imm);
570 * Try again to connect to transport service.
572 * @param cls the handle to the transport service
577 struct GNUNET_TRANSPORT_CoreHandle *h = cls;
578 struct GNUNET_MQ_MessageHandler handlers[] =
579 { GNUNET_MQ_hd_fixed_size(connect,
580 GNUNET_MESSAGE_TYPE_TRANSPORT_CONNECT,
581 struct ConnectInfoMessage,
583 GNUNET_MQ_hd_fixed_size(disconnect,
584 GNUNET_MESSAGE_TYPE_TRANSPORT_DISCONNECT,
585 struct DisconnectInfoMessage,
587 GNUNET_MQ_hd_fixed_size(send_ok,
588 GNUNET_MESSAGE_TYPE_TRANSPORT_SEND_OK,
589 struct SendOkMessage,
591 GNUNET_MQ_hd_var_size(recv,
592 GNUNET_MESSAGE_TYPE_TRANSPORT_RECV,
593 struct InboundMessage,
595 GNUNET_MQ_handler_end() };
596 struct GNUNET_MQ_Envelope *env;
597 struct StartMessage *s;
600 h->reconnect_task = NULL;
601 LOG(GNUNET_ERROR_TYPE_DEBUG, "Connecting to transport service.\n");
602 GNUNET_assert(NULL == h->mq);
604 GNUNET_CLIENT_connect(h->cfg, "transport", handlers, &mq_error_handler, h);
607 env = GNUNET_MQ_msg(s, GNUNET_MESSAGE_TYPE_TRANSPORT_START);
611 if (NULL != h->handlers)
613 s->options = htonl(options);
615 GNUNET_MQ_send(h->mq, env);
620 * Disconnect from the transport service.
622 * @param h transport service to reconnect
625 disconnect(struct GNUNET_TRANSPORT_CoreHandle *h)
627 GNUNET_CONTAINER_multipeermap_iterate(h->neighbours, &neighbour_delete, h);
630 GNUNET_MQ_destroy(h->mq);
637 * Function that will schedule the job that will try
638 * to connect us again to the client.
640 * @param h transport service to reconnect
643 disconnect_and_schedule_reconnect(struct GNUNET_TRANSPORT_CoreHandle *h)
645 GNUNET_assert(NULL == h->reconnect_task);
647 LOG(GNUNET_ERROR_TYPE_DEBUG,
648 "Scheduling task to reconnect to transport service in %s.\n",
649 GNUNET_STRINGS_relative_time_to_string(h->reconnect_delay, GNUNET_YES));
651 GNUNET_SCHEDULER_add_delayed(h->reconnect_delay, &reconnect, h);
652 h->reconnect_delay = GNUNET_TIME_STD_BACKOFF(h->reconnect_delay);
657 * Checks if a given peer is connected to us and get the message queue.
659 * @param handle connection to transport service
660 * @param peer the peer to check
661 * @return NULL if disconnected, otherwise message queue for @a peer
663 struct GNUNET_MQ_Handle *
664 GNUNET_TRANSPORT_core_get_mq(struct GNUNET_TRANSPORT_CoreHandle *handle,
665 const struct GNUNET_PeerIdentity *peer)
669 n = neighbour_find(handle, peer);
677 * Notification from the CORE service to the TRANSPORT service
678 * that the CORE service has finished processing a message from
679 * TRANSPORT (via the @code{handlers} of #GNUNET_TRANSPORT_core_connect())
680 * and that it is thus now OK for TRANSPORT to send more messages
683 * Used to provide flow control, this is our equivalent to
684 * #GNUNET_SERVICE_client_continue() of an ordinary service.
686 * Note that due to the use of a window, TRANSPORT may send multiple
687 * messages destined for the same peer even without an intermediate
688 * call to this function. However, CORE must still call this function
689 * once per message received, as otherwise eventually the window will
690 * be full and TRANSPORT will stop providing messages to CORE for @a
693 * @param ch core handle
694 * @param pid which peer was the message from that was fully processed by CORE
697 GNUNET_TRANSPORT_core_receive_continue(struct GNUNET_TRANSPORT_CoreHandle *ch,
698 const struct GNUNET_PeerIdentity *pid)
700 struct GNUNET_MQ_Envelope *env;
701 struct RecvOkMessage *rok;
703 LOG(GNUNET_ERROR_TYPE_DEBUG,
704 "Message for %s finished CORE processing, sending RECV_OK.\n",
708 env = GNUNET_MQ_msg(rok, GNUNET_MESSAGE_TYPE_TRANSPORT_RECV_OK);
709 rok->increase_window_delta = htonl(1);
711 GNUNET_MQ_send(ch->mq, env);
716 * Connect to the transport service. Note that the connection may
717 * complete (or fail) asynchronously.
719 * @param cfg configuration to use
720 * @param self our own identity (API should check that it matches
721 * the identity found by transport), or NULL (no check)
722 * @param cls closure for the callbacks
723 * @param rec receive function to call
724 * @param nc function to call on connect events
725 * @param nd function to call on disconnect events
726 * @return NULL on error
728 struct GNUNET_TRANSPORT_CoreHandle *
729 GNUNET_TRANSPORT_core_connect(const struct GNUNET_CONFIGURATION_Handle *cfg,
730 const struct GNUNET_PeerIdentity *self,
731 const struct GNUNET_MQ_MessageHandler *handlers,
733 GNUNET_TRANSPORT_NotifyConnect nc,
734 GNUNET_TRANSPORT_NotifyDisconnect nd)
736 struct GNUNET_TRANSPORT_CoreHandle *h;
739 h = GNUNET_new(struct GNUNET_TRANSPORT_CoreHandle);
743 h->check_self = GNUNET_YES;
749 h->reconnect_delay = GNUNET_TIME_UNIT_ZERO;
750 if (NULL != handlers)
752 for (i = 0; NULL != handlers[i].cb; i++)
754 h->handlers = GNUNET_new_array(i + 1, struct GNUNET_MQ_MessageHandler);
755 GNUNET_memcpy(h->handlers,
757 i * sizeof(struct GNUNET_MQ_MessageHandler));
759 LOG(GNUNET_ERROR_TYPE_DEBUG, "Connecting to transport service\n");
763 GNUNET_free_non_null(h->handlers);
768 GNUNET_CONTAINER_multipeermap_create(STARTING_NEIGHBOURS_SIZE, GNUNET_YES);
774 * Disconnect from the transport service.
776 * @param handle handle to the service as returned from
777 * #GNUNET_TRANSPORT_core_connect()
780 GNUNET_TRANSPORT_core_disconnect(struct GNUNET_TRANSPORT_CoreHandle *handle)
782 LOG(GNUNET_ERROR_TYPE_DEBUG, "Transport disconnect called!\n");
783 /* this disconnects all neighbours... */
785 /* and now we stop trying to connect again... */
786 if (NULL != handle->reconnect_task)
788 GNUNET_SCHEDULER_cancel(handle->reconnect_task);
789 handle->reconnect_task = NULL;
791 GNUNET_CONTAINER_multipeermap_destroy(handle->neighbours);
792 handle->neighbours = NULL;
793 GNUNET_free_non_null(handle->handlers);
794 handle->handlers = NULL;
799 /* end of transport_api_core.c */