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Diffstat (limited to 'src/dht/dht_api.c')
| -rw-r--r-- | src/dht/dht_api.c | 997 |
1 files changed, 997 insertions, 0 deletions
diff --git a/src/dht/dht_api.c b/src/dht/dht_api.c new file mode 100644 index 0000000..3cb13b4 --- /dev/null +++ b/src/dht/dht_api.c @@ -0,0 +1,997 @@ +/* + 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, GNUNET_NO); + 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, GNUNET_YES); + 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. + * + * @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) + * @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); + GNUNET_free (handle); +} + + + +/* end of dht_api.c */ |