/* This file is part of GNUnet. (C) 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 dht/dht_api.c * @brief library to access the DHT service * @author Christian Grothoff * @author Nathan Evans */ #include "platform.h" #include "gnunet_util_lib.h" #include "gnunet_constants.h" #include "gnunet_arm_service.h" #include "gnunet_hello_lib.h" #include "gnunet_protocols.h" #include "gnunet_dht_service.h" #include "dht.h" #define LOG(kind,...) GNUNET_log_from (kind, "dht-api",__VA_ARGS__) /** * Entry in our list of messages to be (re-)transmitted. */ struct PendingMessage { /** * This is a doubly-linked list. */ struct PendingMessage *prev; /** * This is a doubly-linked list. */ struct PendingMessage *next; /** * Message that is pending, allocated at the end * of this struct. */ const struct GNUNET_MessageHeader *msg; /** * Handle to the DHT API context. */ struct GNUNET_DHT_Handle *handle; /** * Continuation to call when the request has been * transmitted (for the first time) to the service; can be NULL. */ GNUNET_SCHEDULER_Task cont; /** * Closure for 'cont'. */ void *cont_cls; /** * Timeout task for this message */ GNUNET_SCHEDULER_TaskIdentifier timeout_task; /** * Unique ID for this request */ uint64_t unique_id; /** * Free the saved message once sent, set to GNUNET_YES for messages * that do not receive responses; GNUNET_NO if this pending message * is aliased from a 'struct GNUNET_DHT_RouteHandle' and will be freed * from there. */ int free_on_send; /** * GNUNET_YES if this message is in our pending queue right now. */ int in_pending_queue; }; /** * Handle to a GET request */ struct GNUNET_DHT_GetHandle { /** * Iterator to call on data receipt */ GNUNET_DHT_GetIterator iter; /** * Closure for the iterator callback */ void *iter_cls; /** * Main handle to this DHT api */ struct GNUNET_DHT_Handle *dht_handle; /** * The actual message sent for this request, * used for retransmitting requests on service * failure/reconnect. Freed on route_stop. */ struct PendingMessage *message; /** * Key that this get request is for */ GNUNET_HashCode key; /** * Unique identifier for this request (for key collisions). */ uint64_t unique_id; }; /** * Handle to a monitoring request. */ struct GNUNET_DHT_MonitorHandle { /** * DLL. */ struct GNUNET_DHT_MonitorHandle *next; /** * DLL. */ struct GNUNET_DHT_MonitorHandle *prev; /** * Main handle to this DHT api. */ struct GNUNET_DHT_Handle *dht_handle; /** * Type of block looked for. */ enum GNUNET_BLOCK_Type type; /** * Key being looked for, NULL == all. */ GNUNET_HashCode *key; /** * Callback for each received message of interest. */ GNUNET_DHT_MonitorCB cb; /** * Closure for cb. */ void *cb_cls; }; /** * Connection to the DHT service. */ struct GNUNET_DHT_Handle { /** * Configuration to use. */ const struct GNUNET_CONFIGURATION_Handle *cfg; /** * Socket (if available). */ struct GNUNET_CLIENT_Connection *client; /** * Currently pending transmission request (or NULL). */ struct GNUNET_CLIENT_TransmitHandle *th; /** * Head of linked list of messages we would like to transmit. */ struct PendingMessage *pending_head; /** * Tail of linked list of messages we would like to transmit. */ struct PendingMessage *pending_tail; /** * Head of linked list of messages we would like to monitor. */ struct GNUNET_DHT_MonitorHandle *monitor_head; /** * Tail of linked list of messages we would like to monitor. */ struct GNUNET_DHT_MonitorHandle *monitor_tail; /** * Hash map containing the current outstanding unique requests * (values are of type 'struct GNUNET_DHT_RouteHandle'). */ struct GNUNET_CONTAINER_MultiHashMap *active_requests; /** * Task for trying to reconnect. */ GNUNET_SCHEDULER_TaskIdentifier reconnect_task; /** * How quickly should we retry? Used for exponential back-off on * connect-errors. */ struct GNUNET_TIME_Relative retry_time; /** * Generator for unique ids. */ uint64_t uid_gen; /** * Did we start our receive loop yet? */ int in_receive; }; /** * Handler for messages received from the DHT service * a demultiplexer which handles numerous message types * */ static void service_message_handler (void *cls, const struct GNUNET_MessageHeader *msg); /** * Try to (re)connect to the DHT service. * * @return GNUNET_YES on success, GNUNET_NO on failure. */ static int try_connect (struct GNUNET_DHT_Handle *handle) { if (handle->client != NULL) return GNUNET_OK; handle->in_receive = GNUNET_NO; handle->client = GNUNET_CLIENT_connect ("dht", handle->cfg); if (handle->client == NULL) { LOG (GNUNET_ERROR_TYPE_WARNING, _("Failed to connect to the DHT service!\n")); return GNUNET_NO; } return GNUNET_YES; } /** * Add the request corresponding to the given route handle * to the pending queue (if it is not already in there). * * @param cls the 'struct GNUNET_DHT_Handle*' * @param key key for the request (not used) * @param value the 'struct GNUNET_DHT_GetHandle*' * @return GNUNET_YES (always) */ static int add_request_to_pending (void *cls, const GNUNET_HashCode * key, void *value) { struct GNUNET_DHT_Handle *handle = cls; struct GNUNET_DHT_GetHandle *rh = value; if (GNUNET_NO == rh->message->in_pending_queue) { LOG (GNUNET_ERROR_TYPE_DEBUG, "Retransmitting request related to %s to DHT %p\n", GNUNET_h2s (key), handle); GNUNET_CONTAINER_DLL_insert (handle->pending_head, handle->pending_tail, rh->message); rh->message->in_pending_queue = GNUNET_YES; } return GNUNET_YES; } /** * Try to send messages from list of messages to send * @param handle DHT_Handle */ static void process_pending_messages (struct GNUNET_DHT_Handle *handle); /** * Try reconnecting to the dht service. * * @param cls GNUNET_DHT_Handle * @param tc scheduler context */ static void try_reconnect (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { struct GNUNET_DHT_Handle *handle = cls; LOG (GNUNET_ERROR_TYPE_DEBUG, "Reconnecting with DHT %p\n", handle); handle->reconnect_task = GNUNET_SCHEDULER_NO_TASK; if (handle->retry_time.rel_value < GNUNET_CONSTANTS_SERVICE_RETRY.rel_value) handle->retry_time = GNUNET_CONSTANTS_SERVICE_RETRY; else handle->retry_time = GNUNET_TIME_relative_multiply (handle->retry_time, 2); if (handle->retry_time.rel_value > GNUNET_CONSTANTS_SERVICE_TIMEOUT.rel_value) handle->retry_time = GNUNET_CONSTANTS_SERVICE_TIMEOUT; handle->reconnect_task = GNUNET_SCHEDULER_NO_TASK; if (GNUNET_YES != try_connect (handle)) { LOG (GNUNET_ERROR_TYPE_DEBUG, "dht reconnect failed(!)\n"); return; } GNUNET_CONTAINER_multihashmap_iterate (handle->active_requests, &add_request_to_pending, handle); process_pending_messages (handle); } /** * Try reconnecting to the DHT service. * * @param handle handle to dht to (possibly) disconnect and reconnect */ static void do_disconnect (struct GNUNET_DHT_Handle *handle) { if (handle->client == NULL) return; GNUNET_assert (handle->reconnect_task == GNUNET_SCHEDULER_NO_TASK); if (NULL != handle->th) GNUNET_CLIENT_notify_transmit_ready_cancel (handle->th); handle->th = NULL; GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Disconnecting from DHT service, will try to reconnect in %llu ms\n", (unsigned long long) handle->retry_time.rel_value); GNUNET_CLIENT_disconnect (handle->client); handle->client = NULL; handle->reconnect_task = GNUNET_SCHEDULER_add_delayed (handle->retry_time, &try_reconnect, handle); } /** * Transmit the next pending message, called by notify_transmit_ready */ static size_t transmit_pending (void *cls, size_t size, void *buf); /** * Try to send messages from list of messages to send */ static void process_pending_messages (struct GNUNET_DHT_Handle *handle) { struct PendingMessage *head; if (handle->client == NULL) { GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "process_pending_messages called, but client is null, reconnecting\n"); do_disconnect (handle); return; } if (handle->th != NULL) return; if (NULL == (head = handle->pending_head)) return; handle->th = GNUNET_CLIENT_notify_transmit_ready (handle->client, ntohs (head->msg->size), GNUNET_TIME_UNIT_FOREVER_REL, GNUNET_YES, &transmit_pending, handle); if (NULL != handle->th) return; GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "notify_transmit_ready returned NULL, reconnecting\n"); do_disconnect (handle); } /** * Transmit the next pending message, called by notify_transmit_ready */ static size_t transmit_pending (void *cls, size_t size, void *buf) { struct GNUNET_DHT_Handle *handle = cls; struct PendingMessage *head; size_t tsize; handle->th = NULL; if (buf == NULL) { LOG (GNUNET_ERROR_TYPE_DEBUG, "Transmission to DHT service failed! Reconnecting!\n"); do_disconnect (handle); return 0; } if (NULL == (head = handle->pending_head)) return 0; tsize = ntohs (head->msg->size); if (size < tsize) { process_pending_messages (handle); return 0; } memcpy (buf, head->msg, tsize); GNUNET_CONTAINER_DLL_remove (handle->pending_head, handle->pending_tail, head); head->in_pending_queue = GNUNET_NO; if (head->timeout_task != GNUNET_SCHEDULER_NO_TASK) { GNUNET_SCHEDULER_cancel (head->timeout_task); head->timeout_task = GNUNET_SCHEDULER_NO_TASK; } if (NULL != head->cont) { head->cont (head->cont_cls, NULL); head->cont = NULL; head->cont_cls = NULL; } if (GNUNET_YES == head->free_on_send) GNUNET_free (head); process_pending_messages (handle); LOG (GNUNET_ERROR_TYPE_DEBUG, "Forwarded request of %u bytes to DHT service\n", (unsigned int) tsize); if (GNUNET_NO == handle->in_receive) { LOG (GNUNET_ERROR_TYPE_DEBUG, "Starting to process replies from DHT\n"); handle->in_receive = GNUNET_YES; GNUNET_CLIENT_receive (handle->client, &service_message_handler, handle, GNUNET_TIME_UNIT_FOREVER_REL); } return tsize; } /** * Process a given reply that might match the given * request. * * @param cls the 'struct GNUNET_DHT_ClientResultMessage' * @param key query of the request * @param value the 'struct GNUNET_DHT_RouteHandle' of a request matching the same key * @return GNUNET_YES to continue to iterate over all results, * GNUNET_NO if the reply is malformed */ static int process_reply (void *cls, const GNUNET_HashCode * key, void *value) { const struct GNUNET_DHT_ClientResultMessage *dht_msg = cls; struct GNUNET_DHT_GetHandle *get_handle = value; const struct GNUNET_PeerIdentity *put_path; const struct GNUNET_PeerIdentity *get_path; uint32_t put_path_length; uint32_t get_path_length; size_t data_length; size_t msize; size_t meta_length; const void *data; if (dht_msg->unique_id != get_handle->unique_id) { /* UID mismatch */ LOG (GNUNET_ERROR_TYPE_DEBUG, "Ignoring reply for %s: UID mismatch: %llu/%llu\n", GNUNET_h2s (key), dht_msg->unique_id, get_handle->unique_id); return GNUNET_YES; } msize = ntohs (dht_msg->header.size); put_path_length = ntohl (dht_msg->put_path_length); get_path_length = ntohl (dht_msg->get_path_length); meta_length = sizeof (struct GNUNET_DHT_ClientResultMessage) + sizeof (struct GNUNET_PeerIdentity) * (get_path_length + put_path_length); if ((msize < meta_length) || (get_path_length > GNUNET_SERVER_MAX_MESSAGE_SIZE / sizeof (struct GNUNET_PeerIdentity)) || (put_path_length > GNUNET_SERVER_MAX_MESSAGE_SIZE / sizeof (struct GNUNET_PeerIdentity))) { GNUNET_break (0); return GNUNET_NO; } data_length = msize - meta_length; LOG (GNUNET_ERROR_TYPE_DEBUG, "Giving %u byte reply for %s to application\n", (unsigned int) data_length, GNUNET_h2s (key)); put_path = (const struct GNUNET_PeerIdentity *) &dht_msg[1]; get_path = &put_path[put_path_length]; data = &get_path[get_path_length]; get_handle->iter (get_handle->iter_cls, GNUNET_TIME_absolute_ntoh (dht_msg->expiration), key, get_path, get_path_length, put_path, put_path_length, ntohl (dht_msg->type), data_length, data); return GNUNET_YES; } /** * Process a monitoring message from the service. * * @param handle The DHT handle. * @param msg Message from the service. * * @return GNUNET_OK if everything went fine, * GNUNET_SYSERR if the message is malformed. */ static int process_monitor_message (struct GNUNET_DHT_Handle *handle, const struct GNUNET_MessageHeader *msg) { struct GNUNET_DHT_MonitorMessage *m; struct GNUNET_DHT_MonitorHandle *h; size_t msize; if (ntohs (msg->type) < GNUNET_MESSAGE_TYPE_DHT_MONITOR_GET || ntohs (msg->type) > GNUNET_MESSAGE_TYPE_DHT_MONITOR_PUT) return GNUNET_SYSERR; msize = ntohs (msg->size); if (msize < sizeof (struct GNUNET_DHT_MonitorMessage)) return GNUNET_SYSERR; m = (struct GNUNET_DHT_MonitorMessage *) msg; h = handle->monitor_head; while (NULL != h) { if (h->type == ntohl(m->type) && (NULL == h->key || memcmp (h->key, &m->key, sizeof (GNUNET_HashCode)) == 0)) { struct GNUNET_PeerIdentity *path; uint32_t getl; uint32_t putl; path = (struct GNUNET_PeerIdentity *) &m[1]; getl = ntohl (m->get_path_length); putl = ntohl (m->put_path_length); h->cb (h->cb_cls, ntohs(msg->type), GNUNET_TIME_absolute_ntoh(m->expiration), &m->key, &path[getl], putl, path, getl, ntohl (m->desired_replication_level), ntohl (m->options), ntohl (m->type), (void *) &path[getl + putl], ntohs (msg->size) - sizeof (struct GNUNET_DHT_MonitorMessage) - sizeof (struct GNUNET_PeerIdentity) * (putl + getl)); } h = h->next; } return GNUNET_OK; } /** * Handler for messages received from the DHT service * a demultiplexer which handles numerous message types * * @param cls the 'struct GNUNET_DHT_Handle' * @param msg the incoming message */ static void service_message_handler (void *cls, const struct GNUNET_MessageHeader *msg) { struct GNUNET_DHT_Handle *handle = cls; const struct GNUNET_DHT_ClientResultMessage *dht_msg; if (msg == NULL) { LOG (GNUNET_ERROR_TYPE_DEBUG, "Error receiving data from DHT service, reconnecting\n"); do_disconnect (handle); return; } if (ntohs (msg->type) != GNUNET_MESSAGE_TYPE_DHT_CLIENT_RESULT) { if (process_monitor_message (handle, msg) == GNUNET_OK) { GNUNET_CLIENT_receive (handle->client, &service_message_handler, handle, GNUNET_TIME_UNIT_FOREVER_REL); return; } GNUNET_break (0); do_disconnect (handle); return; } if (ntohs (msg->size) < sizeof (struct GNUNET_DHT_ClientResultMessage)) { GNUNET_break (0); do_disconnect (handle); return; } dht_msg = (const struct GNUNET_DHT_ClientResultMessage *) msg; LOG (GNUNET_ERROR_TYPE_DEBUG, "Received reply for `%s' from DHT service %p\n", GNUNET_h2s (&dht_msg->key), handle); GNUNET_CONTAINER_multihashmap_get_multiple (handle->active_requests, &dht_msg->key, &process_reply, (void *) dht_msg); GNUNET_CLIENT_receive (handle->client, &service_message_handler, handle, GNUNET_TIME_UNIT_FOREVER_REL); } /** * Initialize the connection with the DHT service. * * @param cfg configuration to use * @param ht_len size of the internal hash table to use for * processing multiple GET/FIND requests in parallel * * @return handle to the DHT service, or NULL on error */ struct GNUNET_DHT_Handle * GNUNET_DHT_connect (const struct GNUNET_CONFIGURATION_Handle *cfg, unsigned int ht_len) { struct GNUNET_DHT_Handle *handle; handle = GNUNET_malloc (sizeof (struct GNUNET_DHT_Handle)); handle->cfg = cfg; handle->uid_gen = GNUNET_CRYPTO_random_u64 (GNUNET_CRYPTO_QUALITY_WEAK, UINT64_MAX); handle->active_requests = GNUNET_CONTAINER_multihashmap_create (ht_len); if (GNUNET_NO == try_connect (handle)) { GNUNET_DHT_disconnect (handle); return NULL; } return handle; } /** * Shutdown connection with the DHT service. * * @param handle handle of the DHT connection to stop */ void GNUNET_DHT_disconnect (struct GNUNET_DHT_Handle *handle) { struct PendingMessage *pm; GNUNET_assert (handle != NULL); GNUNET_assert (0 == GNUNET_CONTAINER_multihashmap_size (handle->active_requests)); if (handle->th != NULL) { GNUNET_CLIENT_notify_transmit_ready_cancel (handle->th); handle->th = NULL; } while (NULL != (pm = handle->pending_head)) { GNUNET_assert (GNUNET_YES == pm->in_pending_queue); GNUNET_CONTAINER_DLL_remove (handle->pending_head, handle->pending_tail, pm); pm->in_pending_queue = GNUNET_NO; GNUNET_assert (GNUNET_YES == pm->free_on_send); if (GNUNET_SCHEDULER_NO_TASK != pm->timeout_task) GNUNET_SCHEDULER_cancel (pm->timeout_task); if (NULL != pm->cont) pm->cont (pm->cont_cls, NULL); GNUNET_free (pm); } if (handle->client != NULL) { GNUNET_CLIENT_disconnect (handle->client); handle->client = NULL; } if (handle->reconnect_task != GNUNET_SCHEDULER_NO_TASK) GNUNET_SCHEDULER_cancel (handle->reconnect_task); GNUNET_CONTAINER_multihashmap_destroy (handle->active_requests); GNUNET_free (handle); } /** * Timeout for the transmission of a fire&forget-request. Clean it up. * * @param cls the 'struct PendingMessage' * @param tc scheduler context */ static void timeout_put_request (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { struct PendingMessage *pending = cls; struct GNUNET_DHT_Handle *handle; handle = pending->handle; GNUNET_assert (GNUNET_YES == pending->in_pending_queue); GNUNET_CONTAINER_DLL_remove (handle->pending_head, handle->pending_tail, pending); pending->in_pending_queue = GNUNET_NO; if (pending->cont != NULL) pending->cont (pending->cont_cls, tc); GNUNET_free (pending); } /** * Perform a PUT operation storing data in the DHT. FIXME: we should * change the protocol to get a confirmation for the PUT from the DHT * and call 'cont' only after getting the confirmation; otherwise, the * client has no good way of telling if the 'PUT' message actually got * to the DHT service! * * @param handle handle to DHT service * @param key the key to store under * @param desired_replication_level estimate of how many * nearest peers this request should reach * @param options routing options for this message * @param type type of the value * @param size number of bytes in data; must be less than 64k * @param data the data to store * @param exp desired expiration time for the value * @param timeout how long to wait for transmission of this request * @param cont continuation to call when done (transmitting request to service) * You must not call GNUNET_DHT_DISCONNECT in this continuation * @param cont_cls closure for cont */ void GNUNET_DHT_put (struct GNUNET_DHT_Handle *handle, const GNUNET_HashCode * key, uint32_t desired_replication_level, enum GNUNET_DHT_RouteOption options, enum GNUNET_BLOCK_Type type, size_t size, const char *data, struct GNUNET_TIME_Absolute exp, struct GNUNET_TIME_Relative timeout, GNUNET_SCHEDULER_Task cont, void *cont_cls) { struct GNUNET_DHT_ClientPutMessage *put_msg; size_t msize; struct PendingMessage *pending; msize = sizeof (struct GNUNET_DHT_ClientPutMessage) + size; if ((msize >= GNUNET_SERVER_MAX_MESSAGE_SIZE) || (size >= GNUNET_SERVER_MAX_MESSAGE_SIZE)) { GNUNET_break (0); if (NULL != cont) cont (cont_cls, NULL); return; } pending = GNUNET_malloc (sizeof (struct PendingMessage) + msize); put_msg = (struct GNUNET_DHT_ClientPutMessage *) &pending[1]; pending->msg = &put_msg->header; pending->handle = handle; pending->cont = cont; pending->cont_cls = cont_cls; pending->free_on_send = GNUNET_YES; pending->timeout_task = GNUNET_SCHEDULER_add_delayed (timeout, &timeout_put_request, pending); put_msg->header.size = htons (msize); put_msg->header.type = htons (GNUNET_MESSAGE_TYPE_DHT_CLIENT_PUT); put_msg->type = htonl (type); put_msg->options = htonl ((uint32_t) options); put_msg->desired_replication_level = htonl (desired_replication_level); put_msg->expiration = GNUNET_TIME_absolute_hton (exp); put_msg->key = *key; memcpy (&put_msg[1], data, size); GNUNET_CONTAINER_DLL_insert (handle->pending_head, handle->pending_tail, pending); pending->in_pending_queue = GNUNET_YES; process_pending_messages (handle); } /** * Perform an asynchronous GET operation on the DHT identified. See * also "GNUNET_BLOCK_evaluate". * * @param handle handle to the DHT service * @param timeout how long to wait for transmission of this request to the service * @param type expected type of the response object * @param key the key to look up * @param desired_replication_level estimate of how many nearest peers this request should reach * @param options routing options for this message * @param xquery extended query data (can be NULL, depending on type) * @param xquery_size number of bytes in xquery * @param iter function to call on each result * @param iter_cls closure for iter * @return handle to stop the async get */ struct GNUNET_DHT_GetHandle * GNUNET_DHT_get_start (struct GNUNET_DHT_Handle *handle, struct GNUNET_TIME_Relative timeout, enum GNUNET_BLOCK_Type type, const GNUNET_HashCode * key, uint32_t desired_replication_level, enum GNUNET_DHT_RouteOption options, const void *xquery, size_t xquery_size, GNUNET_DHT_GetIterator iter, void *iter_cls) { struct GNUNET_DHT_ClientGetMessage *get_msg; struct GNUNET_DHT_GetHandle *get_handle; size_t msize; struct PendingMessage *pending; msize = sizeof (struct GNUNET_DHT_ClientGetMessage) + xquery_size; if ((msize >= GNUNET_SERVER_MAX_MESSAGE_SIZE) || (xquery_size >= GNUNET_SERVER_MAX_MESSAGE_SIZE)) { GNUNET_break (0); return NULL; } LOG (GNUNET_ERROR_TYPE_DEBUG, "Sending query for %s to DHT %p\n", GNUNET_h2s (key), handle); pending = GNUNET_malloc (sizeof (struct PendingMessage) + msize); get_msg = (struct GNUNET_DHT_ClientGetMessage *) &pending[1]; pending->msg = &get_msg->header; pending->handle = handle; pending->free_on_send = GNUNET_NO; get_msg->header.size = htons (msize); get_msg->header.type = htons (GNUNET_MESSAGE_TYPE_DHT_CLIENT_GET); get_msg->options = htonl ((uint32_t) options); get_msg->desired_replication_level = htonl (desired_replication_level); get_msg->type = htonl (type); get_msg->key = *key; handle->uid_gen++; get_msg->unique_id = handle->uid_gen; memcpy (&get_msg[1], xquery, xquery_size); GNUNET_CONTAINER_DLL_insert (handle->pending_head, handle->pending_tail, pending); pending->in_pending_queue = GNUNET_YES; get_handle = GNUNET_malloc (sizeof (struct GNUNET_DHT_GetHandle)); get_handle->iter = iter; get_handle->iter_cls = iter_cls; get_handle->message = pending; get_handle->unique_id = get_msg->unique_id; GNUNET_CONTAINER_multihashmap_put (handle->active_requests, key, get_handle, GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE); process_pending_messages (handle); return get_handle; } /** * Stop async DHT-get. * * @param get_handle handle to the GET operation to stop */ void GNUNET_DHT_get_stop (struct GNUNET_DHT_GetHandle *get_handle) { struct GNUNET_DHT_Handle *handle; const struct GNUNET_DHT_ClientGetMessage *get_msg; struct GNUNET_DHT_ClientGetStopMessage *stop_msg; struct PendingMessage *pending; handle = get_handle->message->handle; get_msg = (const struct GNUNET_DHT_ClientGetMessage *) get_handle->message->msg; LOG (GNUNET_ERROR_TYPE_DEBUG, "Sending STOP for %s to DHT via %p\n", GNUNET_h2s (&get_msg->key), handle); /* generate STOP */ pending = GNUNET_malloc (sizeof (struct PendingMessage) + sizeof (struct GNUNET_DHT_ClientGetStopMessage)); stop_msg = (struct GNUNET_DHT_ClientGetStopMessage *) &pending[1]; pending->msg = &stop_msg->header; pending->handle = handle; pending->free_on_send = GNUNET_YES; stop_msg->header.size = htons (sizeof (struct GNUNET_DHT_ClientGetStopMessage)); stop_msg->header.type = htons (GNUNET_MESSAGE_TYPE_DHT_CLIENT_GET_STOP); stop_msg->reserved = htonl (0); stop_msg->unique_id = get_msg->unique_id; stop_msg->key = get_msg->key; GNUNET_CONTAINER_DLL_insert (handle->pending_head, handle->pending_tail, pending); pending->in_pending_queue = GNUNET_YES; /* remove 'GET' from active status */ GNUNET_assert (GNUNET_YES == GNUNET_CONTAINER_multihashmap_remove (handle->active_requests, &get_msg->key, get_handle)); if (GNUNET_YES == get_handle->message->in_pending_queue) { GNUNET_CONTAINER_DLL_remove (handle->pending_head, handle->pending_tail, get_handle->message); get_handle->message->in_pending_queue = GNUNET_NO; } GNUNET_free (get_handle->message); GNUNET_free (get_handle); process_pending_messages (handle); } /** * Start monitoring the local DHT service. * * @param handle Handle to the DHT service. * @param type Type of blocks that are of interest. * @param key Key of data of interest, NULL for all. * @param cb Callback to process all monitored data. * @param cb_cls Closure for cb. * * @return Handle to stop monitoring. */ struct GNUNET_DHT_MonitorHandle * GNUNET_DHT_monitor_start (struct GNUNET_DHT_Handle *handle, enum GNUNET_BLOCK_Type type, const GNUNET_HashCode *key, GNUNET_DHT_MonitorCB cb, void *cb_cls) { struct GNUNET_DHT_MonitorHandle *h; struct GNUNET_DHT_MonitorMessage *m; struct PendingMessage *pending; h = GNUNET_malloc (sizeof (struct GNUNET_DHT_MonitorHandle)); GNUNET_CONTAINER_DLL_insert(handle->monitor_head, handle->monitor_tail, h); GNUNET_assert (NULL != cb); h->cb = cb; h->cb_cls = cb_cls; h->type = type; h->dht_handle = handle; if (NULL != key) { h->key = GNUNET_malloc (sizeof(GNUNET_HashCode)); memcpy (h->key, key, sizeof(GNUNET_HashCode)); } pending = GNUNET_malloc (sizeof (struct GNUNET_DHT_MonitorMessage) + sizeof (struct PendingMessage)); m = (struct GNUNET_DHT_MonitorMessage *) &pending[1]; pending->msg = &m->header; pending->handle = handle; pending->free_on_send = GNUNET_YES; m->header.type = htons (GNUNET_MESSAGE_TYPE_DHT_MONITOR_GET); m->header.size = htons (sizeof (struct GNUNET_DHT_MonitorMessage)); m->type = htonl(type); if (NULL != key) memcpy (&m->key, key, sizeof(GNUNET_HashCode)); GNUNET_CONTAINER_DLL_insert (handle->pending_head, handle->pending_tail, pending); pending->in_pending_queue = GNUNET_YES; process_pending_messages (handle); return h; } /** * Stop monitoring. * * @param handle The handle to the monitor request returned by monitor_start. * * On return get_handle will no longer be valid, caller must not use again!!! */ void GNUNET_DHT_monitor_stop (struct GNUNET_DHT_MonitorHandle *handle) { GNUNET_free_non_null (handle->key); GNUNET_CONTAINER_DLL_remove (handle->dht_handle->monitor_head, handle->dht_handle->monitor_tail, handle); /* FIXME notify service of stop */ GNUNET_free (handle); } /* end of dht_api.c */