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Diffstat (limited to 'src/gns/gns_api.c')
| -rw-r--r-- | src/gns/gns_api.c | 635 |
1 files changed, 635 insertions, 0 deletions
diff --git a/src/gns/gns_api.c b/src/gns/gns_api.c new file mode 100644 index 0000000..ec9c159 --- /dev/null +++ b/src/gns/gns_api.c @@ -0,0 +1,635 @@ +/* + 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. +*/ + +/** + * TODO: Do we really need a client API? + * + * @file gns/gns_api.c + * @brief library to access the GNS service + * @author Martin Schanzenbach + */ + +#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 "gns.h" +#include "gnunet_gns_service.h" + +#define DEBUG_GNS_API GNUNET_EXTRA_LOGGING + +#define LOG(kind,...) GNUNET_log_from (kind, "gns-api",__VA_ARGS__) + +/* TODO into gnunet_protocols */ +#define GNUNET_MESSAGE_TYPE_GNS_CLIENT_LOOKUP 23 +#define GNUNET_MESSAGE_TYPE_GNS_CLIENT_RESULT 24 + +/** + * 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 GNS API context. + */ + struct GNUNET_GNS_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 Lookup request + */ +struct GNUNET_GNS_LookupHandle +{ + + /** + * Iterator to call on data receipt + */ + GNUNET_GNS_LookupIterator iter; + + /** + * Closure for the iterator callback + */ + void *iter_cls; + + /** + * Main handle to this GNS api + */ + struct GNUNET_GNS_Handle *gns_handle; + + /** + * Key that this get request is for + */ + GNUNET_HashCode key; + + /** + * Unique identifier for this request (for key collisions). + */ + uint64_t unique_id; + + struct PendingMessage *message; + +}; + +/** + * Connection to the GNS service. + */ +struct GNUNET_GNS_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; + + /** + * Hash map containing the current outstanding unique requests. + */ + struct GNUNET_CONTAINER_MultiHashMap *active_requests; + + 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; +}; + +/** + * Try to send messages from list of messages to send + * @param handle GNS_Handle + */ +static void +process_pending_messages (struct GNUNET_GNS_Handle *handle); + +/** + * Try to (re)connect to the GNS service. + * + * @return GNUNET_YES on success, GNUNET_NO on failure. + */ +static int +try_connect (struct GNUNET_GNS_Handle *handle) +{ + if (handle->client != NULL) + return GNUNET_OK; + handle->in_receive = GNUNET_NO; + handle->client = GNUNET_CLIENT_connect ("gns", handle->cfg); + if (handle->client == NULL) + { + LOG (GNUNET_ERROR_TYPE_WARNING, + _("Failed to connect to the GNS service!\n")); + return GNUNET_NO; + } + return GNUNET_YES; +} + +/** + * Add the request corresponding to the given handle + * to the pending queue (if it is not already in there). + * + * @param cls the 'struct GNUNET_GNS_Handle*' + * @param key key for the request (not used) + * @param value the 'struct GNUNET_GNS_LookupHandle*' + * @return GNUNET_YES (always) + */ +static int +add_request_to_pending (void *cls, const GNUNET_HashCode * key, void *value) +{ + struct GNUNET_GNS_Handle *handle = cls; + struct GNUNET_GNS_LookupHandle *rh = value; + + if (GNUNET_NO == rh->message->in_pending_queue) + { +#if DEBUG_DHT + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Retransmitting request related to %s to GNS %p\n", GNUNET_h2s(key), + handle); +#endif + GNUNET_CONTAINER_DLL_insert (handle->pending_head, handle->pending_tail, + rh->message); + rh->message->in_pending_queue = GNUNET_YES; + } + return GNUNET_YES; +} + +/** + * Try reconnecting to the GNS service. + * + * @param cls GNUNET_GNS_Handle + * @param tc scheduler context + */ +static void +try_reconnect (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) +{ + struct GNUNET_GNS_Handle *handle = cls; + +#if DEBUG_GNS + LOG (GNUNET_ERROR_TYPE_DEBUG, "Reconnecting with GNS %p\n", handle); +#endif + 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)) + { +#if DEBUG_GNS + LOG (GNUNET_ERROR_TYPE_DEBUG, "GNS reconnect failed(!)\n"); +#endif + return; + } + GNUNET_CONTAINER_multihashmap_iterate (handle->active_requests, + &add_request_to_pending, handle); + process_pending_messages (handle); +} + + +/** + * Try reconnecting to the GNS service. + * + * @param handle handle to gns to (possibly) disconnect and reconnect + */ +static void +do_disconnect (struct GNUNET_GNS_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 GNS 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); + +/** + * Handler for messages received from the GNS service + * + * @param cls the 'struct GNUNET_GNS_Handle' + * @param msg the incoming message + */ +static void +message_handler (void *cls, const struct GNUNET_MessageHeader *msg); + +/** + * Try to send messages from list of messages to send + */ +static void +process_pending_messages (struct GNUNET_GNS_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_GNS_Handle *handle = cls; + struct PendingMessage *head; + size_t tsize; + + handle->th = NULL; + if (buf == NULL) + { + GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, + "Transmission to GNS 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 (GNUNET_YES == head->free_on_send) + GNUNET_free (head); + process_pending_messages (handle); +#if DEBUG_GNS + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Forwarded request of %u bytes to GNS service\n", (unsigned int) tsize); +#endif + if (GNUNET_NO == handle->in_receive) + { +#if DEBUG_GNS + LOG (GNUNET_ERROR_TYPE_DEBUG, "Starting to process replies from GNS\n"); +#endif + handle->in_receive = GNUNET_YES; + GNUNET_CLIENT_receive (handle->client, &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_GNS_ClientResultMessage' + * @param key query of the request + * @param value the 'struct GNUNET_GNS_LookupHandle' 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_GNS_ClientResultMessage *gns_msg = cls; + struct GNUNET_GNS_LookupHandle *lookup_handle = value; + const char *name = (const char*) &lookup_handle[1]; + const struct GNUNET_NAMESTORE_RecordData *records; + uint32_t num_records; + size_t meta_length; + size_t msize; + + if (gns_msg->unique_id != lookup_handle->unique_id) + { + /* UID mismatch */ +#if DEBUG_GNS + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Ignoring reply for %s: UID mismatch: %llu/%llu\n", GNUNET_h2s (key), + gns_msg->unique_id, lookup_handle->unique_id); +#endif + return GNUNET_YES; + } + msize = ntohs (gns_msg->header.size); + num_records = ntohl (gns_msg->num_records); + meta_length = + sizeof (struct GNUNET_GNS_ClientResultMessage) + + sizeof (struct GNUNET_NAMESTORE_RecordData) * (num_records); + if ((msize < meta_length) || + (num_records > + GNUNET_SERVER_MAX_MESSAGE_SIZE / sizeof (struct GNUNET_NAMESTORE_RecordData))) + { + GNUNET_break (0); + return GNUNET_NO; + } +#if DEBUG_GNS + LOG (GNUNET_ERROR_TYPE_DEBUG, "Giving %u byte reply for %s to application\n", + (unsigned int) (msize - meta_length), GNUNET_h2s (key)); +#endif + records = (const struct GNUNET_NAMESTORE_RecordData *) &gns_msg[1]; + lookup_handle->iter (lookup_handle->iter_cls, name, records, num_records); + return GNUNET_YES; +} + + +/** + * Handler for messages received from the GNS service + * + * @param cls the 'struct GNUNET_GNS_Handle' + * @param msg the incoming message + */ +static void +message_handler (void *cls, const struct GNUNET_MessageHeader *msg) +{ + struct GNUNET_GNS_Handle *handle = cls; + const struct GNUNET_GNS_ClientResultMessage *gns_msg; + + if (msg == NULL) + { +#if DEBUG_GNS + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Error receiving data from GNS service, reconnecting\n"); +#endif + do_disconnect (handle); + return; + } + if (ntohs (msg->type) != GNUNET_MESSAGE_TYPE_GNS_CLIENT_RESULT) + { + GNUNET_break (0); + do_disconnect (handle); + return; + } + if (ntohs (msg->size) < sizeof (struct GNUNET_GNS_ClientResultMessage)) + { + GNUNET_break (0); + do_disconnect (handle); + return; + } + gns_msg = (const struct GNUNET_GNS_ClientResultMessage *) msg; +#if DEBUG_GNS + LOG (GNUNET_ERROR_TYPE_DEBUG, "Received reply for `%s' from GNS service %p\n", + &gns_msg->name, handle); +#endif + /* TODO uniquely identify requests... maybe hash(name) or uid */ + GNUNET_CONTAINER_multihashmap_get_multiple (handle->active_requests, + &gns_msg->key, &process_reply, + (void *) gns_msg); + GNUNET_CLIENT_receive (handle->client, &message_handler, handle, + GNUNET_TIME_UNIT_FOREVER_REL); +} + + +/** + * Initialize the connection with the GNS service. + * + * @param cfg configuration to use + * @param ht_len size of the internal hash table to use for parallel requests + * @return handle to the GNS service, or NULL on error + */ +struct GNUNET_GNS_Handle * +GNUNET_GNS_connect (const struct GNUNET_CONFIGURATION_Handle *cfg, + unsigned int ht_len) +{ + struct GNUNET_GNS_Handle *handle; + + handle = GNUNET_malloc (sizeof (struct GNUNET_GNS_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_GNS_disconnect (handle); + return NULL; + } + return handle; +} + + +/** + * Shutdown connection with the GNS service. + * + * @param handle handle of the GNS connection to stop + */ +void +GNUNET_GNS_disconnect (struct GNUNET_GNS_Handle *handle) +{ + /* disco from GNS */ +} + + +/** + * Perform an asynchronous Lookup operation on the GNS. + * TODO: + * - Still not sure what we query for... "names" it is for now + * - Do we need such sophisticated message queueing like dht? simplify? + * + * @param handle handle to the GNS service + * @param timeout how long to wait for transmission of this request to the service + * @param name the name to look up + * @param iter function to call on each result + * @param iter_cls closure for iter + * @return handle to stop the async get + */ +struct GNUNET_GNS_LookupHandle * +GNUNET_GNS_lookup_start (struct GNUNET_GNS_Handle *handle, + struct GNUNET_TIME_Relative timeout, + const char * name, + enum GNUNET_GNS_RecordType type, + GNUNET_GNS_LookupIterator iter, + void *iter_cls) +{ + /* IPC to look for local entries, start dht lookup, return lookup_handle */ + struct GNUNET_GNS_ClientLookupMessage *lookup_msg; + struct GNUNET_GNS_LookupHandle *lookup_handle; + GNUNET_HashCode key; + size_t msize; + struct PendingMessage *pending; + + if (NULL == name) + { + return NULL; + } + + GNUNET_CRYPTO_hash (name, strlen(name), &key); + + msize = sizeof (struct GNUNET_GNS_ClientLookupMessage) + strlen(name); +#if DEBUG_GNS + LOG (GNUNET_ERROR_TYPE_DEBUG, "Starting lookup for %s in GNS %p\n", + name, handle); +#endif + pending = GNUNET_malloc (sizeof (struct PendingMessage) + msize); + lookup_msg = (struct GNUNET_GNS_ClientLookupMessage *) &pending[1]; + pending->msg = &lookup_msg->header; + pending->handle = handle; + pending->free_on_send = GNUNET_NO; + lookup_msg->header.size = htons (msize); + lookup_msg->header.type = htons (GNUNET_MESSAGE_TYPE_GNS_CLIENT_LOOKUP); + lookup_msg->key = key; + memcpy(&lookup_msg[1], name, strlen(name)); + handle->uid_gen++; + lookup_msg->unique_id = handle->uid_gen; + GNUNET_CONTAINER_DLL_insert (handle->pending_head, handle->pending_tail, + pending); + pending->in_pending_queue = GNUNET_YES; + lookup_handle = GNUNET_malloc (sizeof (struct GNUNET_GNS_LookupHandle)); + lookup_handle->iter = iter; + lookup_handle->iter_cls = iter_cls; + lookup_handle->message = pending; + lookup_handle->unique_id = lookup_msg->unique_id; + GNUNET_CONTAINER_multihashmap_put (handle->active_requests, &lookup_msg->key, + lookup_handle, + GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE); + process_pending_messages (handle); + return lookup_handle; +} + + +/** + * Stop async GNS lookup. + * + * @param lookup_handle handle to the GNS lookup operation to stop + */ +void +GNUNET_GNS_lookup_stop (struct GNUNET_GNS_LookupHandle *lookup_handle) +{ + /* TODO Stop dht lookups */ +} + + +/* end of gns_api.c */ |