/* This file is part of GNUnet. (C) 2001-2014 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_util_lib.h" #include "gnunet_protocols.h" #include "peerinfo.h" #define LOG(kind,...) GNUNET_log_from (kind, "peerinfo-api",__VA_ARGS__) /** * Entry in the transmission queue to PEERINFO service. We use * the same structure for queueing 'iteration' requests and * actual 'add' messages. */ struct GNUNET_PEERINFO_AddContext { /** * This is a linked list. */ struct GNUNET_PEERINFO_AddContext *next; /** * This is a linked list. */ struct GNUNET_PEERINFO_AddContext *prev; /** * Handle to the PEERINFO service. */ struct GNUNET_PEERINFO_Handle *h; /** * Function to call after request has been transmitted, or NULL. */ GNUNET_PEERINFO_Continuation cont; /** * Closure for 'cont'. */ void *cont_cls; /** * Number of bytes of the request message (follows after this struct). */ size_t size; }; /** * Context for an iteration request. */ struct GNUNET_PEERINFO_IteratorContext { /** * Kept in a DLL. */ struct GNUNET_PEERINFO_IteratorContext *next; /** * Kept in a DLL. */ struct GNUNET_PEERINFO_IteratorContext *prev; /** * Handle to the PEERINFO service. */ struct GNUNET_PEERINFO_Handle *h; /** * Function to call with the results. */ GNUNET_PEERINFO_Processor callback; /** * Closure for @e callback. */ void *callback_cls; /** * Our entry in the transmission queue. */ struct GNUNET_PEERINFO_AddContext *ac; /** * Task responsible for timeout. */ struct GNUNET_SCHEDULER_Task * timeout_task; /** * Timeout for the operation. */ struct GNUNET_TIME_Absolute timeout; /** * Peer we are interested in (only valid if iteration was restricted to one peer). */ struct GNUNET_PeerIdentity peer; /** * Is @e peer set? */ int have_peer; /** * Set to #GNUNET_YES if we are currently receiving replies from the * service. */ int request_transmitted; }; /** * 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 GNUNET_PEERINFO_AddContext *ac_head; /** * Tail of transmission queue. */ struct GNUNET_PEERINFO_AddContext *ac_tail; /** * Handle for the current transmission request, or NULL if none is pending. */ struct GNUNET_CLIENT_TransmitHandle *th; /** * Head of iterator DLL. */ struct GNUNET_PEERINFO_IteratorContext *ic_head; /** * Tail of iterator DLL. */ struct GNUNET_PEERINFO_IteratorContext *ic_tail; /** * ID for a reconnect task. */ struct GNUNET_SCHEDULER_Task * r_task; /** * Are we now receiving? */ 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 *h; h = GNUNET_new (struct GNUNET_PEERINFO_Handle); h->client = GNUNET_CLIENT_connect ("peerinfo", cfg); h->cfg = cfg; return h; } /** * 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 GNUNET_PEERINFO_AddContext *ac; struct GNUNET_PEERINFO_IteratorContext *ic; while (NULL != (ic = h->ic_head)) { GNUNET_break (GNUNET_YES == ic->request_transmitted); ic->request_transmitted = GNUNET_NO; GNUNET_PEERINFO_iterate_cancel (ic); } while (NULL != (ac = h->ac_head)) { GNUNET_CONTAINER_DLL_remove (h->ac_head, h->ac_tail, ac); if (NULL != ac->cont) ac->cont (ac->cont_cls, _("aborted due to explicit disconnect request")); GNUNET_free (ac); } if (NULL != h->th) { GNUNET_CLIENT_notify_transmit_ready_cancel (h->th); h->th = NULL; } if (NULL != h->client) { GNUNET_CLIENT_disconnect (h->client); h->client = NULL; } if (NULL != h->r_task) { GNUNET_SCHEDULER_cancel (h->r_task); h->r_task = NULL; } 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 tc scheduler context */ static void reconnect_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { struct GNUNET_PEERINFO_Handle *h = cls; h->r_task = NULL; 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 (NULL != h->r_task) { GNUNET_SCHEDULER_cancel (h->r_task); h->r_task = NULL; } if (NULL != h->th) { GNUNET_CLIENT_notify_transmit_ready_cancel (h->th); h->th = NULL; } if (NULL != h->client) { GNUNET_CLIENT_disconnect (h->client); h->client = NULL; } h->in_receive = GNUNET_NO; 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 @a buf (0 on error) * @param buf where to copy the message * @return number of bytes copied to @a buf */ static size_t do_transmit (void *cls, size_t size, void *buf) { struct GNUNET_PEERINFO_Handle *h = cls; struct GNUNET_PEERINFO_AddContext *ac = h->ac_head; size_t ret; h->th = NULL; if (NULL == ac) return 0; /* request was cancelled in the meantime */ if (NULL == buf) { /* peerinfo service died */ LOG (GNUNET_ERROR_TYPE_DEBUG | GNUNET_ERROR_TYPE_BULK, "Failed to transmit message to `%s' service.\n", "PEERINFO"); GNUNET_CONTAINER_DLL_remove (h->ac_head, h->ac_tail, ac); reconnect (h); if (NULL != ac->cont) ac->cont (ac->cont_cls, _("failed to transmit request (service down?)")); GNUNET_free (ac); return 0; } ret = ac->size; if (size < ret) { /* change in head of queue (i.e. cancel + add), try again */ trigger_transmit (h); return 0; } LOG (GNUNET_ERROR_TYPE_DEBUG, "Transmitting request of size %u to `%s' service.\n", ret, "PEERINFO"); memcpy (buf, &ac[1], ret); GNUNET_CONTAINER_DLL_remove (h->ac_head, h->ac_tail, ac); trigger_transmit (h); if (NULL != ac->cont) ac->cont (ac->cont_cls, NULL); GNUNET_free (ac); 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 GNUNET_PEERINFO_AddContext *ac; if (NULL == (ac = h->ac_head)) return; /* no requests queued */ if (NULL != h->th) return; /* request already pending */ if (NULL == h->client) { /* disconnected, try to reconnect */ reconnect (h); return; } h->th = GNUNET_CLIENT_notify_transmit_ready (h->client, ac->size, GNUNET_TIME_UNIT_FOREVER_REL, 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 * @param cont continuation to call when done, NULL is allowed * @param cont_cls closure for @a cont * @return handle to cancel add operation; all pending * 'add' operations will be cancelled automatically * on disconnect, so it is not necessary to keep this * handle (unless 'cont' is NULL and at some point * calling 'cont' must be prevented) */ struct GNUNET_PEERINFO_AddContext * GNUNET_PEERINFO_add_peer (struct GNUNET_PEERINFO_Handle *h, const struct GNUNET_HELLO_Message *hello, GNUNET_PEERINFO_Continuation cont, void *cont_cls) { uint16_t hs = GNUNET_HELLO_size (hello); struct GNUNET_PEERINFO_AddContext *ac; struct GNUNET_PeerIdentity peer; GNUNET_assert (GNUNET_OK == GNUNET_HELLO_get_id (hello, &peer)); LOG (GNUNET_ERROR_TYPE_DEBUG, "Adding peer `%s' to PEERINFO database (%u bytes of `%s')\n", GNUNET_i2s (&peer), hs, "HELLO"); ac = GNUNET_malloc (sizeof (struct GNUNET_PEERINFO_AddContext) + hs); ac->h = h; ac->size = hs; ac->cont = cont; ac->cont_cls = cont_cls; memcpy (&ac[1], hello, hs); GNUNET_CONTAINER_DLL_insert_tail (h->ac_head, h->ac_tail, ac); trigger_transmit (h); return ac; } /** * Cancel pending 'add' operation. Must only be called before * either 'cont' or #GNUNET_PEERINFO_disconnect() are invoked. * * @param ac handle for the add operation to cancel */ void GNUNET_PEERINFO_add_peer_cancel (struct GNUNET_PEERINFO_AddContext *ac) { struct GNUNET_PEERINFO_Handle *h = ac->h; GNUNET_CONTAINER_DLL_remove (h->ac_head, h->ac_tail, ac); GNUNET_free (ac); } /** * Type of a function to call when we receive a message from the * service. Call the iterator with the result and (if applicable) * continue to receive more messages or trigger processing the next * event (if applicable). * * @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_Handle *h = cls; struct GNUNET_PEERINFO_IteratorContext *ic = h->ic_head; const struct InfoMessage *im; const struct GNUNET_HELLO_Message *hello; GNUNET_PEERINFO_Processor cb; struct GNUNET_PeerIdentity id; void *cb_cls; uint16_t ms; h->in_receive = GNUNET_NO; if (NULL == msg) { /* peerinfo service died, signal error */ if (NULL != ic) { cb = ic->callback; cb_cls = ic->callback_cls; GNUNET_PEERINFO_iterate_cancel (ic); } else { cb = NULL; } reconnect (h); if (NULL != cb) cb (cb_cls, NULL, NULL, _("Failed to receive response from `PEERINFO' service.")); return; } if (NULL == ic) { /* didn't expect a response, reconnect */ reconnect (h); return; } ic->request_transmitted = GNUNET_NO; cb = ic->callback; cb_cls = ic->callback_cls; if (GNUNET_MESSAGE_TYPE_PEERINFO_INFO_END == ntohs (msg->type)) { /* normal end of list of peers, signal end, process next pending request */ LOG (GNUNET_ERROR_TYPE_DEBUG, "Received end of list of peers from `%s' service\n", "PEERINFO"); GNUNET_PEERINFO_iterate_cancel (ic); trigger_transmit (h); if ( (GNUNET_NO == h->in_receive) && (NULL != h->ic_head) ) { h->in_receive = GNUNET_YES; GNUNET_CLIENT_receive (h->client, &peerinfo_handler, h, GNUNET_TIME_absolute_get_remaining (h->ic_head->timeout)); } if (NULL != cb) cb (cb_cls, NULL, NULL, NULL); return; } ms = ntohs (msg->size); if ((ms < sizeof (struct InfoMessage)) || (ntohs (msg->type) != GNUNET_MESSAGE_TYPE_PEERINFO_INFO)) { /* malformed message */ GNUNET_break (0); GNUNET_PEERINFO_iterate_cancel (ic); reconnect (h); if (NULL != cb) cb (cb_cls, NULL, NULL, _("Received invalid message from `PEERINFO' service.")); return; } im = (const struct InfoMessage *) msg; GNUNET_break (0 == ntohl (im->reserved)); if ( (GNUNET_YES == ic->have_peer) && (0 != memcmp (&ic->peer, &im->peer, sizeof (struct GNUNET_PeerIdentity))) ) { /* bogus message (from a different iteration call?); out of sequence! */ LOG (GNUNET_ERROR_TYPE_ERROR, "Received HELLO for peer `%s', expected peer `%s'\n", GNUNET_i2s (&im->peer), GNUNET_i2s (&ic->peer)); GNUNET_break (0); GNUNET_PEERINFO_iterate_cancel (ic); reconnect (h); if (NULL != cb) cb (cb_cls, NULL, NULL, _("Received invalid message from `PEERINFO' service.")); return; } 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)) { /* malformed message */ GNUNET_break (0); GNUNET_PEERINFO_iterate_cancel (ic); reconnect (h); if (NULL != cb) cb (cb_cls, NULL, NULL, _("Received invalid message from `PEERINFO' service.")); return; } if (GNUNET_OK != GNUNET_HELLO_get_id (hello, &id)) { /* malformed message */ GNUNET_break (0); GNUNET_PEERINFO_iterate_cancel (ic); reconnect (h); if (NULL != cb) cb (cb_cls, NULL, NULL, _("Received invalid message from `PEERINFO' service.")); return; } if (0 != memcmp (&im->peer, &id, sizeof (struct GNUNET_PeerIdentity))) { /* malformed message */ GNUNET_break (0); GNUNET_PEERINFO_iterate_cancel (ic); reconnect (h); if (NULL != cb) cb (cb_cls, NULL, NULL, _("Received invalid message from `PEERINFO' service.")); return; } } /* normal data message */ 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"); h->in_receive = GNUNET_YES; GNUNET_CLIENT_receive (h->client, &peerinfo_handler, h, GNUNET_TIME_absolute_get_remaining (ic->timeout)); if (NULL != cb) cb (cb_cls, &im->peer, hello, NULL); } /** * 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 emsg error message, NULL if transmission worked */ static void iterator_start_receive (void *cls, const char *emsg) { struct GNUNET_PEERINFO_IteratorContext *ic = cls; struct GNUNET_PEERINFO_Handle *h = ic->h; GNUNET_PEERINFO_Processor cb; void *cb_cls; ic->ac = NULL; if (NULL != emsg) { cb = ic->callback; cb_cls = ic->callback_cls; GNUNET_PEERINFO_iterate_cancel (ic); reconnect (h); if (NULL != cb) cb (cb_cls, NULL, NULL, emsg); return; } LOG (GNUNET_ERROR_TYPE_DEBUG, "Waiting for response from `%s' service.\n", "PEERINFO"); ic->request_transmitted = GNUNET_YES; if (GNUNET_NO == h->in_receive) { h->in_receive = GNUNET_YES; GNUNET_CLIENT_receive (h->client, &peerinfo_handler, h, 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; GNUNET_PEERINFO_Processor cb; void *cb_cls; ic->timeout_task = NULL; cb = ic->callback; cb_cls = ic->callback_cls; GNUNET_PEERINFO_iterate_cancel (ic); if (NULL != cb) cb (cb_cls, NULL, NULL, _("Timeout transmitting iteration request to `PEERINFO' service.")); } /** * Call a method for each known matching host. 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 include_friend_only include HELLO messages for friends only * @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 @a callback * @return iterator context */ struct GNUNET_PEERINFO_IteratorContext * GNUNET_PEERINFO_iterate (struct GNUNET_PEERINFO_Handle *h, int include_friend_only, const struct GNUNET_PeerIdentity *peer, struct GNUNET_TIME_Relative timeout, GNUNET_PEERINFO_Processor callback, void *callback_cls) { struct ListAllPeersMessage *lapm; struct ListPeerMessage *lpm; struct GNUNET_PEERINFO_IteratorContext *ic; struct GNUNET_PEERINFO_AddContext *ac; ic = GNUNET_new (struct GNUNET_PEERINFO_IteratorContext); if (NULL == peer) { LOG (GNUNET_ERROR_TYPE_DEBUG, "Requesting list of peers from PEERINFO service\n"); ac = GNUNET_malloc (sizeof (struct GNUNET_PEERINFO_AddContext) + sizeof (struct ListAllPeersMessage)); ac->size = sizeof (struct ListAllPeersMessage); lapm = (struct ListAllPeersMessage *) &ac[1]; lapm->header.size = htons (sizeof (struct ListAllPeersMessage)); lapm->header.type = htons (GNUNET_MESSAGE_TYPE_PEERINFO_GET_ALL); lapm->include_friend_only = htonl (include_friend_only); } else { LOG (GNUNET_ERROR_TYPE_DEBUG, "Requesting information on peer `%4s' from PEERINFO service\n", GNUNET_i2s (peer)); ac = GNUNET_malloc (sizeof (struct GNUNET_PEERINFO_AddContext) + sizeof (struct ListPeerMessage)); ac->size = sizeof (struct ListPeerMessage); lpm = (struct ListPeerMessage *) &ac[1]; lpm->header.size = htons (sizeof (struct ListPeerMessage)); lpm->header.type = htons (GNUNET_MESSAGE_TYPE_PEERINFO_GET); lpm->include_friend_only = htonl (include_friend_only); memcpy (&lpm->peer, peer, sizeof (struct GNUNET_PeerIdentity)); ic->have_peer = GNUNET_YES; ic->peer = *peer; } ic->h = h; ic->ac = ac; 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); ac->cont = &iterator_start_receive; ac->cont_cls = ic; GNUNET_CONTAINER_DLL_insert_tail (h->ac_head, h->ac_tail, ac); GNUNET_CONTAINER_DLL_insert_tail (h->ic_head, h->ic_tail, ic); 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) { struct GNUNET_PEERINFO_Handle *h; h = ic->h; if (NULL != ic->timeout_task) { GNUNET_SCHEDULER_cancel (ic->timeout_task); ic->timeout_task = NULL; } ic->callback = NULL; if (GNUNET_YES == ic->request_transmitted) return; /* need to finish processing */ GNUNET_CONTAINER_DLL_remove (h->ic_head, h->ic_tail, ic); if (NULL != ic->ac) { GNUNET_CONTAINER_DLL_remove (h->ac_head, h->ac_tail, ic->ac); GNUNET_free (ic->ac); } GNUNET_free (ic); } /* end of peerinfo_api.c */