/* This file is part of GNUnet. (C) 2001, 2002, 2004, 2005, 2007, 2009, 2010 Christian Grothoff (and other contributing authors) GNUnet is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version. GNUnet is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GNUnet; see the file COPYING. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ /** * @file peerinfo/peerinfo_api.c * @brief API to access peerinfo service * @author Christian Grothoff */ #include "platform.h" #include "gnunet_client_lib.h" #include "gnunet_container_lib.h" #include "gnunet_peerinfo_service.h" #include "gnunet_protocols.h" #include "gnunet_time_lib.h" #include "peerinfo.h" /** * Function to call after transmission has succeeded. * * @param cls closure * @param success GNUNET_OK if transmission worked, GNUNET_SYSERR on error */ typedef void (*TransmissionContinuation)(void *cls, int success); /** * Entry in the transmission queue to PEERINFO service. */ struct TransmissionQueueEntry { /** * This is a linked list. */ struct TransmissionQueueEntry *next; /** * This is a linked list. */ struct TransmissionQueueEntry *prev; /** * Function to call after request has been transmitted, or NULL (in which * case we must consider sending the next entry immediately). */ TransmissionContinuation cont; /** * Closure for 'cont'. */ void *cont_cls; /** * Timeout for the operation. */ struct GNUNET_TIME_Absolute timeout; /** * Number of bytes of the request message (follows after this struct). */ size_t size; }; /** * Handle to the peerinfo service. */ struct GNUNET_PEERINFO_Handle { /** * Our configuration. */ const struct GNUNET_CONFIGURATION_Handle *cfg; /** * Connection to the service. */ struct GNUNET_CLIENT_Connection *client; /** * Head of transmission queue. */ struct TransmissionQueueEntry *tq_head; /** * Tail of transmission queue. */ struct TransmissionQueueEntry *tq_tail; /** * Handle for the current transmission request, or NULL if none is pending. */ struct GNUNET_CLIENT_TransmitHandle *th; /** * ID for a reconnect task. */ GNUNET_SCHEDULER_TaskIdentifier r_task; /** * Set to GNUNET_YES if we are currently receiving replies from the * service. */ int in_receive; }; /** * Connect to the peerinfo service. * * @param cfg configuration to use * @return NULL on error (configuration related, actual connection * establishment may happen asynchronously). */ struct GNUNET_PEERINFO_Handle * GNUNET_PEERINFO_connect (const struct GNUNET_CONFIGURATION_Handle *cfg) { struct GNUNET_PEERINFO_Handle *ret; ret = GNUNET_malloc (sizeof (struct GNUNET_PEERINFO_Handle)); ret->client = GNUNET_CLIENT_connect ("peerinfo", cfg); ret->cfg = cfg; return ret; } /** * Disconnect from the peerinfo service. Note that all iterators must * have completed or have been cancelled by the time this function is * called (otherwise, calling this function is a serious error). * Furthermore, if 'GNUNET_PEERINFO_add_peer' operations are still * pending, they will be cancelled silently on disconnect. * * @param h handle to disconnect */ void GNUNET_PEERINFO_disconnect (struct GNUNET_PEERINFO_Handle *h) { struct TransmissionQueueEntry *tqe; while (NULL != (tqe = h->tq_head)) { GNUNET_CONTAINER_DLL_remove (h->tq_head, h->tq_tail, tqe); if (tqe->cont != NULL) tqe->cont (tqe->cont_cls, GNUNET_SYSERR); GNUNET_free (tqe); } if (h->th != NULL) { GNUNET_CLIENT_notify_transmit_ready_cancel (h->th); h->th = NULL; } if (NULL != h->client) { GNUNET_CLIENT_disconnect (h->client, GNUNET_NO); h->client = NULL; } if (GNUNET_SCHEDULER_NO_TASK != h->r_task) { GNUNET_SCHEDULER_cancel (h->r_task); h->r_task = GNUNET_SCHEDULER_NO_TASK; } GNUNET_free (h); } /** * Check if we have a request pending in the transmission queue and are * able to transmit it right now. If so, schedule transmission. * * @param h handle to the service */ static void trigger_transmit (struct GNUNET_PEERINFO_Handle *h); /** * Close the existing connection to PEERINFO and reconnect. * * @param h handle to the service */ static void reconnect (struct GNUNET_PEERINFO_Handle *h); /** * Task scheduled to re-try connecting to the peerinfo service. * * @param cls the 'struct GNUNET_PEERINFO_Handle' * @param ts scheduler context */ static void reconnect_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { struct GNUNET_PEERINFO_Handle *h = cls; h->r_task = GNUNET_SCHEDULER_NO_TASK; reconnect (h); } /** * Close the existing connection to PEERINFO and reconnect. * * @param h handle to the service */ static void reconnect (struct GNUNET_PEERINFO_Handle *h) { if (h->r_task != GNUNET_SCHEDULER_NO_TASK) { GNUNET_SCHEDULER_cancel (h->r_task); h->r_task = GNUNET_SCHEDULER_NO_TASK; } if (NULL != h->th) { GNUNET_CLIENT_notify_transmit_ready_cancel (h->th); h->th = NULL; } if (NULL != h->client) { GNUNET_CLIENT_disconnect (h->client, GNUNET_SYSERR); h->client = NULL; } h->client = GNUNET_CLIENT_connect ("peerinfo", h->cfg); if (NULL == h->client) { h->r_task = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_SECONDS, &reconnect_task, h); return; } trigger_transmit (h); } /** * Transmit the request at the head of the transmission queue * and trigger continuation (if any). * * @param cls the 'struct GNUNET_PEERINFO_Handle' (with the queue) * @param size size of the buffer (0 on error) * @param buf where to copy the message * @return number of bytes copied to buf */ static size_t do_transmit (void *cls, size_t size, void *buf) { struct GNUNET_PEERINFO_Handle *h = cls; struct TransmissionQueueEntry *tqe = h->tq_head; size_t ret; h->th = NULL; if (buf == NULL) { GNUNET_log (GNUNET_ERROR_TYPE_WARNING | GNUNET_ERROR_TYPE_BULK, _("Failed to transmit message to `%s' service.\n"), "PEERINFO"); if (tqe != NULL) GNUNET_CONTAINER_DLL_remove (h->tq_head, h->tq_tail, tqe); reconnect (h); if (tqe != NULL) { if (tqe->cont != NULL) tqe->cont (tqe->cont_cls, GNUNET_SYSERR); GNUNET_free (tqe); } return 0; } /* If it can be NULL above, it can be NULL here to... */ if (tqe == NULL) return 0; ret = tqe->size; GNUNET_assert (size >= ret); memcpy (buf, &tqe[1], ret); #if DEBUG_PEERINFO GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Transmitting request of size %u to `%s' service.\n", ret, "PEERINFO"); #endif GNUNET_CONTAINER_DLL_remove (h->tq_head, h->tq_tail, tqe); if (tqe->cont != NULL) tqe->cont (tqe->cont_cls, GNUNET_OK); else trigger_transmit (h); GNUNET_free (tqe); return ret; } /** * Check if we have a request pending in the transmission queue and are * able to transmit it right now. If so, schedule transmission. * * @param h handle to the service */ static void trigger_transmit (struct GNUNET_PEERINFO_Handle *h) { struct TransmissionQueueEntry *tqe; if (NULL == (tqe = h->tq_head)) return; if (h->th != NULL) return; if (h->in_receive == GNUNET_YES) return; if (NULL == h->client) { reconnect (h); return; } h->th = GNUNET_CLIENT_notify_transmit_ready (h->client, tqe->size, GNUNET_TIME_absolute_get_remaining (tqe->timeout), GNUNET_YES, &do_transmit, h); } /** * Add a host to the persistent list. This method operates in * semi-reliable mode: if the transmission is not completed by * the time 'GNUNET_PEERINFO_disconnect' is called, it will be * aborted. Furthermore, if a second HELLO is added for the * same peer before the first one was transmitted, PEERINFO may * merge the two HELLOs prior to transmission to the service. * * @param h handle to the peerinfo service * @param hello the verified (!) HELLO message */ void GNUNET_PEERINFO_add_peer (struct GNUNET_PEERINFO_Handle *h, const struct GNUNET_HELLO_Message *hello) { uint16_t hs = GNUNET_HELLO_size (hello); struct TransmissionQueueEntry *tqe; #if DEBUG_PEERINFO struct GNUNET_PeerIdentity peer; GNUNET_assert (GNUNET_OK == GNUNET_HELLO_get_id (hello, &peer)); GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Adding peer `%s' to PEERINFO database (%u bytes of `%s')\n", GNUNET_i2s(&peer), hs, "HELLO"); #endif tqe = GNUNET_malloc (sizeof (struct TransmissionQueueEntry) + hs); tqe->size = hs; tqe->timeout = GNUNET_TIME_UNIT_FOREVER_ABS; memcpy (&tqe[1], hello, hs); GNUNET_CONTAINER_DLL_insert_after (h->tq_head, h->tq_tail, h->tq_tail, tqe); trigger_transmit (h); } /** * Context for an iteration request. */ struct GNUNET_PEERINFO_IteratorContext { /** * Handle to the PEERINFO service. */ struct GNUNET_PEERINFO_Handle *h; /** * Function to call with the results. */ GNUNET_PEERINFO_Processor callback; /** * Closure for 'callback'. */ void *callback_cls; /** * Our entry in the transmission queue. */ struct TransmissionQueueEntry *tqe; /** * Task responsible for timeout. */ GNUNET_SCHEDULER_TaskIdentifier timeout_task; /** * Timeout for the operation. */ struct GNUNET_TIME_Absolute timeout; /** * Are we now receiving? */ int in_receive; }; /** * Type of a function to call when we receive a message * from the service. * * @param cls closure * @param msg message received, NULL on timeout or fatal error */ static void peerinfo_handler (void *cls, const struct GNUNET_MessageHeader *msg) { struct GNUNET_PEERINFO_IteratorContext *ic = cls; const struct InfoMessage *im; const struct GNUNET_HELLO_Message *hello; uint16_t ms; ic->h->in_receive = GNUNET_NO; if (msg == NULL) { char *err_msg; GNUNET_asprintf(&err_msg, _("Failed to receive response from `%s' service."), "PEERINFO"); GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "%s\n", err_msg); reconnect (ic->h); if (ic->timeout_task != GNUNET_SCHEDULER_NO_TASK) GNUNET_SCHEDULER_cancel (ic->timeout_task); if (ic->callback != NULL) ic->callback (ic->callback_cls, NULL, NULL, err_msg); GNUNET_free (err_msg); GNUNET_free (ic); return; } if (ntohs (msg->type) == GNUNET_MESSAGE_TYPE_PEERINFO_INFO_END) { #if DEBUG_PEERINFO GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Received end of list of peers from `%s' service\n", "PEERINFO"); #endif trigger_transmit (ic->h); if (ic->timeout_task != GNUNET_SCHEDULER_NO_TASK) GNUNET_SCHEDULER_cancel (ic->timeout_task); if (ic->callback != NULL) ic->callback (ic->callback_cls, NULL, NULL, NULL); GNUNET_free (ic); return; } ms = ntohs (msg->size); if ((ms < sizeof (struct InfoMessage)) || (ntohs (msg->type) != GNUNET_MESSAGE_TYPE_PEERINFO_INFO)) { char * err_msg; GNUNET_asprintf(&err_msg,_("Received invalid message from `%s' service.\n"),"PEERINFO"); GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,err_msg); GNUNET_break (0); reconnect (ic->h); if (ic->timeout_task != GNUNET_SCHEDULER_NO_TASK) GNUNET_SCHEDULER_cancel (ic->timeout_task); if (ic->callback != NULL) ic->callback (ic->callback_cls, NULL, NULL, err_msg); GNUNET_free (err_msg); GNUNET_free (ic); return; } im = (const struct InfoMessage *) msg; GNUNET_break (0 == ntohl (im->reserved)); hello = NULL; if (ms > sizeof (struct InfoMessage) + sizeof (struct GNUNET_MessageHeader)) { hello = (const struct GNUNET_HELLO_Message *) &im[1]; if (ms != sizeof (struct InfoMessage) + GNUNET_HELLO_size (hello)) { char * err_msg; GNUNET_asprintf (&err_msg, _("Received invalid message from `%s' service.\n"), "PEERINFO"); GNUNET_break (0); reconnect (ic->h); if (ic->timeout_task != GNUNET_SCHEDULER_NO_TASK) GNUNET_SCHEDULER_cancel (ic->timeout_task); if (ic->callback != NULL) ic->callback (ic->callback_cls, NULL, NULL, err_msg); GNUNET_free (ic); GNUNET_free (err_msg); return; } } #if DEBUG_PEERINFO GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Received %u bytes of `%s' information about peer `%s' from `%s' service\n", (hello == NULL) ? 0 : (unsigned int) GNUNET_HELLO_size (hello), "HELLO", GNUNET_i2s (&im->peer), "PEERINFO"); #endif ic->h->in_receive = GNUNET_YES; if (ic->callback != NULL) ic->callback (ic->callback_cls, &im->peer, hello, NULL); GNUNET_CLIENT_receive (ic->h->client, &peerinfo_handler, ic, GNUNET_TIME_absolute_get_remaining (ic->timeout)); } /** * We've transmitted the iteration request. Now get ready to process * the results (or handle transmission error). * * @param cls the 'struct GNUNET_PEERINFO_IteratorContext' * @param transmit_success GNUNET_OK if transmission worked */ static void iterator_start_receive (void *cls, int transmit_success) { struct GNUNET_PEERINFO_IteratorContext *ic = cls; if (GNUNET_OK != transmit_success) { char * err_msg; GNUNET_asprintf(&err_msg,_("Failed to transmit iteration request to `%s' service (%d).\n"),"PEERINFO",transmit_success); GNUNET_log (GNUNET_ERROR_TYPE_WARNING,err_msg); if (ic->timeout_task != GNUNET_SCHEDULER_NO_TASK) { GNUNET_SCHEDULER_cancel (ic->timeout_task); ic->timeout_task = GNUNET_SCHEDULER_NO_TASK; } reconnect (ic->h); if (ic->callback != NULL) ic->callback (ic->callback_cls, NULL, NULL, err_msg); GNUNET_free (err_msg); GNUNET_free (ic); return; } #if DEBUG_PEERINFO GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Waiting for response from `%s' service.\n", "PEERINFO"); #endif ic->h->in_receive = GNUNET_YES; ic->in_receive = GNUNET_YES; ic->tqe = NULL; GNUNET_CLIENT_receive (ic->h->client, &peerinfo_handler, ic, GNUNET_TIME_absolute_get_remaining (ic->timeout)); } /** * Peerinfo iteration request has timed out. * * @param cls the 'struct GNUNET_PEERINFO_IteratorContext*' * @param tc scheduler context */ static void signal_timeout (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { struct GNUNET_PEERINFO_IteratorContext *ic = cls; char * err_msg; GNUNET_asprintf(&err_msg,_("Timeout transmitting iteration request to `%s' service.\n"), "PEERINFO"); ic->timeout_task = GNUNET_SCHEDULER_NO_TASK; if (! ic->in_receive) GNUNET_CONTAINER_DLL_remove (ic->h->tq_head, ic->h->tq_tail, ic->tqe); reconnect (ic->h); ic->callback (ic->callback_cls, NULL, NULL, err_msg); ic->callback = NULL; GNUNET_free_non_null (ic->tqe); GNUNET_free (err_msg); GNUNET_free (ic); } /** * Call a method for each known matching host and change its trust * value. The callback method will be invoked once for each matching * host and then finally once with a NULL pointer. After that final * invocation, the iterator context must no longer be used. * * Instead of calling this function with 'peer == NULL' it is often * better to use 'GNUNET_PEERINFO_notify'. * * @param h handle to the peerinfo service * @param peer restrict iteration to this peer only (can be NULL) * @param timeout how long to wait until timing out * @param callback the method to call for each peer * @param callback_cls closure for callback * @return iterator context */ struct GNUNET_PEERINFO_IteratorContext * GNUNET_PEERINFO_iterate (struct GNUNET_PEERINFO_Handle *h, const struct GNUNET_PeerIdentity *peer, struct GNUNET_TIME_Relative timeout, GNUNET_PEERINFO_Processor callback, void *callback_cls) { struct GNUNET_MessageHeader *lapm; struct ListPeerMessage *lpm; struct GNUNET_PEERINFO_IteratorContext *ic; struct TransmissionQueueEntry *tqe; if (peer == NULL) { #if DEBUG_PEERINFO GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Requesting list of peers from PEERINFO service\n"); #endif tqe = GNUNET_malloc (sizeof (struct TransmissionQueueEntry) + sizeof (struct GNUNET_MessageHeader)); tqe->size = sizeof (struct GNUNET_MessageHeader); lapm = (struct GNUNET_MessageHeader *) &tqe[1]; lapm->size = htons (sizeof (struct GNUNET_MessageHeader)); lapm->type = htons (GNUNET_MESSAGE_TYPE_PEERINFO_GET_ALL); } else { #if DEBUG_PEERINFO GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Requesting information on peer `%4s' from PEERINFO service\n", GNUNET_i2s (peer)); #endif tqe = GNUNET_malloc (sizeof (struct TransmissionQueueEntry) + sizeof (struct ListPeerMessage)); tqe->size = sizeof (struct ListPeerMessage); lpm = (struct ListPeerMessage *) &tqe[1]; lpm->header.size = htons (sizeof (struct ListPeerMessage)); lpm->header.type = htons (GNUNET_MESSAGE_TYPE_PEERINFO_GET); memcpy (&lpm->peer, peer, sizeof (struct GNUNET_PeerIdentity)); } ic = GNUNET_malloc (sizeof (struct GNUNET_PEERINFO_IteratorContext)); ic->h = h; ic->tqe = tqe; ic->callback = callback; ic->callback_cls = callback_cls; ic->timeout = GNUNET_TIME_relative_to_absolute (timeout); ic->timeout_task = GNUNET_SCHEDULER_add_delayed (timeout, &signal_timeout, ic); tqe->timeout = ic->timeout; tqe->cont = &iterator_start_receive; tqe->cont_cls = ic; tqe->timeout = ic->timeout; GNUNET_CONTAINER_DLL_insert_after (h->tq_head, h->tq_tail, h->tq_tail, tqe); trigger_transmit (h); return ic; } /** * Cancel an iteration over peer information. * * @param ic context of the iterator to cancel */ void GNUNET_PEERINFO_iterate_cancel (struct GNUNET_PEERINFO_IteratorContext *ic) { if (ic->timeout_task != GNUNET_SCHEDULER_NO_TASK) { GNUNET_SCHEDULER_cancel (ic->timeout_task); ic->timeout_task = GNUNET_SCHEDULER_NO_TASK; } ic->callback = NULL; if (ic->in_receive) return; /* need to finish processing */ GNUNET_CONTAINER_DLL_remove (ic->h->tq_head, ic->h->tq_tail, ic->tqe); GNUNET_free (ic->tqe); GNUNET_free (ic); } /* end of peerinfo_api.c */