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- /*
- This file is part of GNUnet.
- Copyright (C) 2010-2013, 2016 GNUnet e.V.
- GNUnet is free software: you can redistribute it and/or modify it
- under the terms of the GNU Affero General Public License as published
- by the Free Software Foundation, either version 3 of the License,
- 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
- Affero General Public License for more details.
-
- You should have received a copy of the GNU Affero General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>.
- SPDX-License-Identifier: AGPL3.0-or-later
- */
- /**
- * @file namecache/namecache_api.c
- * @brief API to access the NAMECACHE service
- * @author Martin Schanzenbach
- * @author Matthias Wachs
- * @author Christian Grothoff
- */
- #include "platform.h"
- #include "gnunet_util_lib.h"
- #include "gnunet_crypto_lib.h"
- #include "gnunet_constants.h"
- #include "gnunet_dnsparser_lib.h"
- #include "gnunet_gnsrecord_lib.h"
- #include "gnunet_signatures.h"
- #include "gnunet_namecache_service.h"
- #include "namecache.h"
- #define LOG(kind,...) GNUNET_log_from (kind, "namecache-api",__VA_ARGS__)
- /**
- * An QueueEntry used to store information for a pending
- * NAMECACHE record operation
- */
- struct GNUNET_NAMECACHE_QueueEntry
- {
- /**
- * Kept in a DLL.
- */
- struct GNUNET_NAMECACHE_QueueEntry *next;
- /**
- * Kept in a DLL.
- */
- struct GNUNET_NAMECACHE_QueueEntry *prev;
- /**
- * Main handle to access the namecache.
- */
- struct GNUNET_NAMECACHE_Handle *nsh;
- /**
- * Continuation to call
- */
- GNUNET_NAMECACHE_ContinuationWithStatus cont;
- /**
- * Closure for @e cont.
- */
- void *cont_cls;
- /**
- * Function to call with the blocks we get back; or NULL.
- */
- GNUNET_NAMECACHE_BlockProcessor block_proc;
- /**
- * Closure for @e block_proc.
- */
- void *block_proc_cls;
- /**
- * The operation id this zone iteration operation has
- */
- uint32_t op_id;
- };
- /**
- * Connection to the NAMECACHE service.
- */
- struct GNUNET_NAMECACHE_Handle
- {
- /**
- * Configuration to use.
- */
- const struct GNUNET_CONFIGURATION_Handle *cfg;
- /**
- * Message queue to service.
- */
- struct GNUNET_MQ_Handle *mq;
- /**
- * Currently pending transmission request (or NULL).
- */
- struct GNUNET_CLIENT_TransmitHandle *th;
- /**
- * Head of pending namecache queue entries
- */
- struct GNUNET_NAMECACHE_QueueEntry *op_head;
- /**
- * Tail of pending namecache queue entries
- */
- struct GNUNET_NAMECACHE_QueueEntry *op_tail;
- /**
- * Reconnect task
- */
- struct GNUNET_SCHEDULER_Task *reconnect_task;
- /**
- * Delay introduced before we reconnect.
- */
- struct GNUNET_TIME_Relative reconnect_delay;
- /**
- * Should we reconnect to service due to some serious error?
- */
- int reconnect;
- /**
- * The last operation id used for a NAMECACHE operation
- */
- uint32_t last_op_id_used;
- };
- /**
- * Disconnect from service and then reconnect.
- *
- * @param h our handle
- */
- static void
- force_reconnect (struct GNUNET_NAMECACHE_Handle *h);
- /**
- * Find queue entry for the given @a rid.
- *
- * @param h handle to search
- * @param rid request ID to look for
- * @return NULL if not found, otherwise the queue entry (removed from the queue)
- */
- static struct GNUNET_NAMECACHE_QueueEntry *
- find_qe (struct GNUNET_NAMECACHE_Handle *h,
- uint32_t rid)
- {
- struct GNUNET_NAMECACHE_QueueEntry *qe;
- for (qe = h->op_head; qe != NULL; qe = qe->next)
- {
- if (qe->op_id == rid)
- {
- GNUNET_CONTAINER_DLL_remove (h->op_head,
- h->op_tail,
- qe);
- return qe;
- }
- }
- return NULL;
- }
- /**
- * Handle an incoming message of type
- * #GNUNET_MESSAGE_TYPE_NAMECACHE_LOOKUP_BLOCK_RESPONSE.
- *
- * @param cls the `struct GNUNET_NAMECACHE_Handle`
- * @param msg the message we received
- */
- static int
- check_lookup_block_response (void *cls,
- const struct LookupBlockResponseMessage *msg)
- {
- /* any length will do, format validation is in handler */
- return GNUNET_OK;
- }
- /**
- * Handle an incoming message of type
- * #GNUNET_MESSAGE_TYPE_NAMECACHE_LOOKUP_BLOCK_RESPONSE.
- *
- * @param cls the `struct GNUNET_NAMECACHE_Handle`
- * @param msg the message we received
- */
- static void
- handle_lookup_block_response (void *cls,
- const struct LookupBlockResponseMessage *msg)
- {
- struct GNUNET_NAMECACHE_Handle *h = cls;
- size_t size;
- struct GNUNET_NAMECACHE_QueueEntry *qe;
- LOG (GNUNET_ERROR_TYPE_DEBUG,
- "Received LOOKUP_BLOCK_RESPONSE\n");
- qe = find_qe (h,
- ntohl (msg->gns_header.r_id));
- if (NULL == qe)
- return;
- if (0 == GNUNET_TIME_absolute_ntoh (msg->expire).abs_value_us)
- {
- /* no match found */
- if (NULL != qe->block_proc)
- qe->block_proc (qe->block_proc_cls,
- NULL);
- GNUNET_free (qe);
- return;
- }
- size = ntohs (msg->gns_header.header.size)
- - sizeof (struct LookupBlockResponseMessage);
- {
- char buf[size + sizeof (struct GNUNET_GNSRECORD_Block)] GNUNET_ALIGN;
- struct GNUNET_GNSRECORD_Block *block;
- block = (struct GNUNET_GNSRECORD_Block *) buf;
- block->signature = msg->signature;
- block->derived_key = msg->derived_key;
- block->purpose.purpose = htonl (GNUNET_SIGNATURE_PURPOSE_GNS_RECORD_SIGN);
- block->purpose.size = htonl (size +
- sizeof (struct GNUNET_TIME_AbsoluteNBO) +
- sizeof (struct GNUNET_CRYPTO_EccSignaturePurpose));
- block->expiration_time = msg->expire;
- GNUNET_memcpy (&block[1],
- &msg[1],
- size);
- if (GNUNET_OK !=
- GNUNET_GNSRECORD_block_verify (block))
- {
- GNUNET_break (0);
- if (NULL != qe->block_proc)
- qe->block_proc (qe->block_proc_cls,
- NULL);
- force_reconnect (h);
- }
- else
- {
- if (NULL != qe->block_proc)
- qe->block_proc (qe->block_proc_cls,
- block);
- }
- }
- GNUNET_free (qe);
- }
- /**
- * Handle an incoming message of type
- * #GNUNET_MESSAGE_TYPE_NAMECACHE_BLOCK_CACHE_RESPONSE
- *
- * @param cls the `struct GNUNET_NAMECACHE_Handle`
- * @param msg the message we received
- * @param size the message size
- * @return #GNUNET_OK on success, #GNUNET_SYSERR on error and we did NOT notify the client
- */
- static void
- handle_block_cache_response (void *cls,
- const struct BlockCacheResponseMessage *msg)
- {
- struct GNUNET_NAMECACHE_Handle *h = cls;
- struct GNUNET_NAMECACHE_QueueEntry *qe;
- int res;
- LOG (GNUNET_ERROR_TYPE_DEBUG,
- "Received BLOCK_CACHE_RESPONSE\n");
- qe = find_qe (h,
- ntohl (msg->gns_header.r_id));
- if (NULL == qe)
- return;
- res = ntohl (msg->op_result);
- /* TODO: add actual error message from namecache to response... */
- if (NULL != qe->cont)
- qe->cont (qe->cont_cls,
- res,
- (GNUNET_OK == res)
- ? NULL
- : _("Namecache failed to cache block"));
- GNUNET_free (qe);
- }
- /**
- * Generic error handler, called with the appropriate error code and
- * the same closure specified at the creation of the message queue.
- * Not every message queue implementation supports an error handler.
- *
- * @param cls closure with the `struct GNUNET_NAMECACHE_Handle *`
- * @param error error code
- */
- static void
- mq_error_handler (void *cls,
- enum GNUNET_MQ_Error error)
- {
- struct GNUNET_NAMECACHE_Handle *h = cls;
- force_reconnect (h);
- }
- /**
- * Reconnect to namecache service.
- *
- * @param h the handle to the NAMECACHE service
- */
- static void
- reconnect (struct GNUNET_NAMECACHE_Handle *h)
- {
- struct GNUNET_MQ_MessageHandler handlers[] = {
- GNUNET_MQ_hd_var_size (lookup_block_response,
- GNUNET_MESSAGE_TYPE_NAMECACHE_LOOKUP_BLOCK_RESPONSE,
- struct LookupBlockResponseMessage,
- h),
- GNUNET_MQ_hd_fixed_size (block_cache_response,
- GNUNET_MESSAGE_TYPE_NAMECACHE_BLOCK_CACHE_RESPONSE,
- struct BlockCacheResponseMessage,
- h),
- GNUNET_MQ_handler_end ()
- };
- GNUNET_assert (NULL == h->mq);
- h->mq = GNUNET_CLIENT_connect (h->cfg,
- "namecache",
- handlers,
- &mq_error_handler,
- h);
- }
- /**
- * Re-establish the connection to the service.
- *
- * @param cls handle to use to re-connect.
- */
- static void
- reconnect_task (void *cls)
- {
- struct GNUNET_NAMECACHE_Handle *h = cls;
- h->reconnect_task = NULL;
- reconnect (h);
- }
- /**
- * Disconnect from service and then reconnect.
- *
- * @param h our handle
- */
- static void
- force_reconnect (struct GNUNET_NAMECACHE_Handle *h)
- {
- struct GNUNET_NAMECACHE_QueueEntry *qe;
- h->reconnect = GNUNET_NO;
- GNUNET_MQ_destroy (h->mq);
- h->mq = NULL;
- while (NULL != (qe = h->op_head))
- {
- GNUNET_CONTAINER_DLL_remove (h->op_head,
- h->op_tail,
- qe);
- if (NULL != qe->cont)
- qe->cont (qe->cont_cls,
- GNUNET_SYSERR,
- _("Error communicating with namecache service"));
- GNUNET_free (qe);
- }
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "Reconnecting to namecache\n");
- h->reconnect_delay = GNUNET_TIME_STD_BACKOFF (h->reconnect_delay);
- h->reconnect_task = GNUNET_SCHEDULER_add_delayed (h->reconnect_delay,
- &reconnect_task,
- h);
- }
- /**
- * Get a fresh operation id to distinguish between namecache requests
- *
- * @param h the namecache handle
- * @return next operation id to use
- */
- static uint32_t
- get_op_id (struct GNUNET_NAMECACHE_Handle *h)
- {
- return h->last_op_id_used++;
- }
- /**
- * Initialize the connection with the NAMECACHE service.
- *
- * @param cfg configuration to use
- * @return handle to the GNS service, or NULL on error
- */
- struct GNUNET_NAMECACHE_Handle *
- GNUNET_NAMECACHE_connect (const struct GNUNET_CONFIGURATION_Handle *cfg)
- {
- struct GNUNET_NAMECACHE_Handle *h;
- h = GNUNET_new (struct GNUNET_NAMECACHE_Handle);
- h->cfg = cfg;
- reconnect (h);
- if (NULL == h->mq)
- {
- GNUNET_free (h);
- return NULL;
- }
- return h;
- }
- /**
- * Disconnect from the namecache service (and free associated
- * resources).
- *
- * @param h handle to the namecache
- */
- void
- GNUNET_NAMECACHE_disconnect (struct GNUNET_NAMECACHE_Handle *h)
- {
- struct GNUNET_NAMECACHE_QueueEntry *q;
- GNUNET_break (NULL == h->op_head);
- while (NULL != (q = h->op_head))
- {
- GNUNET_CONTAINER_DLL_remove (h->op_head,
- h->op_tail,
- q);
- GNUNET_free (q);
- }
- if (NULL != h->mq)
- {
- GNUNET_MQ_destroy (h->mq);
- h->mq = NULL;
- }
- if (NULL != h->reconnect_task)
- {
- GNUNET_SCHEDULER_cancel (h->reconnect_task);
- h->reconnect_task = NULL;
- }
- GNUNET_free (h);
- }
- /**
- * Store an item in the namecache. If the item is already present,
- * it is replaced with the new record.
- *
- * @param h handle to the namecache
- * @param block block to store
- * @param cont continuation to call when done
- * @param cont_cls closure for @a cont
- * @return handle to abort the request, NULL on error
- */
- struct GNUNET_NAMECACHE_QueueEntry *
- GNUNET_NAMECACHE_block_cache (struct GNUNET_NAMECACHE_Handle *h,
- const struct GNUNET_GNSRECORD_Block *block,
- GNUNET_NAMECACHE_ContinuationWithStatus cont,
- void *cont_cls)
- {
- struct GNUNET_NAMECACHE_QueueEntry *qe;
- struct BlockCacheMessage *msg;
- struct GNUNET_MQ_Envelope *env;
- uint32_t rid;
- size_t blen;
- if (NULL == h->mq)
- return NULL;
- blen = ntohl (block->purpose.size);
- GNUNET_assert (blen > (sizeof (struct GNUNET_TIME_AbsoluteNBO) +
- sizeof (struct GNUNET_CRYPTO_EccSignaturePurpose)));
- blen -= (sizeof (struct GNUNET_TIME_AbsoluteNBO) +
- sizeof (struct GNUNET_CRYPTO_EccSignaturePurpose));
- rid = get_op_id (h);
- qe = GNUNET_new (struct GNUNET_NAMECACHE_QueueEntry);
- qe->nsh = h;
- qe->cont = cont;
- qe->cont_cls = cont_cls;
- qe->op_id = rid;
- GNUNET_CONTAINER_DLL_insert_tail (h->op_head,
- h->op_tail,
- qe);
- /* send msg */
- env = GNUNET_MQ_msg_extra (msg,
- blen,
- GNUNET_MESSAGE_TYPE_NAMECACHE_BLOCK_CACHE);
- msg->gns_header.r_id = htonl (rid);
- msg->expire = block->expiration_time;
- msg->signature = block->signature;
- msg->derived_key = block->derived_key;
- GNUNET_memcpy (&msg[1],
- &block[1],
- blen);
- GNUNET_MQ_send (h->mq,
- env);
- return qe;
- }
- /**
- * Get a result for a particular key from the namecache. The processor
- * will only be called once.
- *
- * @param h handle to the namecache
- * @param derived_hash hash of zone key combined with name to lookup
- * @param proc function to call on the matching block, or with
- * NULL if there is no matching block
- * @param proc_cls closure for @a proc
- * @return a handle that can be used to cancel, NULL on error
- */
- struct GNUNET_NAMECACHE_QueueEntry *
- GNUNET_NAMECACHE_lookup_block (struct GNUNET_NAMECACHE_Handle *h,
- const struct GNUNET_HashCode *derived_hash,
- GNUNET_NAMECACHE_BlockProcessor proc,
- void *proc_cls)
- {
- struct GNUNET_NAMECACHE_QueueEntry *qe;
- struct LookupBlockMessage *msg;
- struct GNUNET_MQ_Envelope *env;
- uint32_t rid;
- if (NULL == h->mq)
- return NULL;
- LOG (GNUNET_ERROR_TYPE_DEBUG,
- "Looking for block under %s\n",
- GNUNET_h2s (derived_hash));
- rid = get_op_id (h);
- qe = GNUNET_new (struct GNUNET_NAMECACHE_QueueEntry);
- qe->nsh = h;
- qe->block_proc = proc;
- qe->block_proc_cls = proc_cls;
- qe->op_id = rid;
- GNUNET_CONTAINER_DLL_insert_tail (h->op_head,
- h->op_tail,
- qe);
- env = GNUNET_MQ_msg (msg,
- GNUNET_MESSAGE_TYPE_NAMECACHE_LOOKUP_BLOCK);
- msg->gns_header.r_id = htonl (rid);
- msg->query = *derived_hash;
- GNUNET_MQ_send (h->mq,
- env);
- return qe;
- }
- /**
- * Cancel a namecache operation. The final callback from the
- * operation must not have been done yet.
- *
- * @param qe operation to cancel
- */
- void
- GNUNET_NAMECACHE_cancel (struct GNUNET_NAMECACHE_QueueEntry *qe)
- {
- struct GNUNET_NAMECACHE_Handle *h = qe->nsh;
- GNUNET_CONTAINER_DLL_remove (h->op_head,
- h->op_tail,
- qe);
- GNUNET_free(qe);
- }
- /* end of namecache_api.c */
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