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- /*
- This file is part of GNUnet.
- Copyright (C) 2013, 2016, 2018 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 namestore/namestore_api_monitor.c
- * @brief API to monitor changes in the NAMESTORE
- * @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_arm_service.h"
- #include "gnunet_signatures.h"
- #include "gnunet_namestore_service.h"
- #include "namestore.h"
- /**
- * Handle for a monitoring activity.
- */
- struct GNUNET_NAMESTORE_ZoneMonitor
- {
- /**
- * Configuration (to reconnect).
- */
- const struct GNUNET_CONFIGURATION_Handle *cfg;
- /**
- * Handle to namestore service.
- */
- struct GNUNET_MQ_Handle *mq;
- /**
- * Function to call on errors.
- */
- GNUNET_SCHEDULER_TaskCallback error_cb;
- /**
- * Closure for @e error_cb.
- */
- void *error_cb_cls;
- /**
- * Function to call on events.
- */
- GNUNET_NAMESTORE_RecordMonitor monitor;
- /**
- * Closure for @e monitor.
- */
- void *monitor_cls;
- /**
- * Function called when we've synchronized.
- */
- GNUNET_SCHEDULER_TaskCallback sync_cb;
- /**
- * Closure for @e sync_cb.
- */
- void *sync_cb_cls;
- /**
- * Monitored zone.
- */
- struct GNUNET_CRYPTO_EcdsaPrivateKey zone;
- /**
- * Do we first iterate over all existing records?
- */
- int iterate_first;
- };
- /**
- * Reconnect to the namestore service.
- *
- * @param zm monitor to reconnect
- */
- static void
- reconnect (struct GNUNET_NAMESTORE_ZoneMonitor *zm);
- /**
- * Handle SYNC message from the namestore service.
- *
- * @param cls the monitor
- * @param msg the sync message
- */
- static void
- handle_sync (void *cls,
- const struct GNUNET_MessageHeader *msg)
- {
- struct GNUNET_NAMESTORE_ZoneMonitor *zm = cls;
- (void) cls;
- (void) msg;
- if (NULL != zm->sync_cb)
- zm->sync_cb (zm->sync_cb_cls);
- }
- /**
- * We've received a notification about a change to our zone.
- * Check that it is well-formed.
- *
- * @param cls the zone monitor handle
- * @param lrm the message from the service.
- */
- static int
- check_result (void *cls,
- const struct RecordResultMessage *lrm)
- {
- static struct GNUNET_CRYPTO_EcdsaPrivateKey zero;
- struct GNUNET_NAMESTORE_ZoneMonitor *zm = cls;
- size_t lrm_len;
- size_t exp_lrm_len;
- size_t name_len;
- size_t rd_len;
- unsigned rd_count;
- const char *name_tmp;
- const char *rd_ser_tmp;
- (void) cls;
- if ( (0 != memcmp (&lrm->private_key,
- &zm->zone,
- sizeof (struct GNUNET_CRYPTO_EcdsaPrivateKey))) &&
- (0 != memcmp (&zero,
- &zm->zone,
- sizeof (struct GNUNET_CRYPTO_EcdsaPrivateKey))) )
- {
- GNUNET_break (0);
- return GNUNET_SYSERR;
- }
- lrm_len = ntohs (lrm->gns_header.header.size);
- rd_len = ntohs (lrm->rd_len);
- rd_count = ntohs (lrm->rd_count);
- name_len = ntohs (lrm->name_len);
- if (name_len > MAX_NAME_LEN)
- {
- GNUNET_break (0);
- return GNUNET_SYSERR;
- }
- exp_lrm_len = sizeof (struct RecordResultMessage) + name_len + rd_len;
- if (lrm_len != exp_lrm_len)
- {
- GNUNET_break (0);
- return GNUNET_SYSERR;
- }
- if (0 == name_len)
- {
- GNUNET_break (0);
- return GNUNET_SYSERR;
- }
- name_tmp = (const char *) &lrm[1];
- if (name_tmp[name_len -1] != '\0')
- {
- GNUNET_break (0);
- return GNUNET_SYSERR;
- }
- rd_ser_tmp = (const char *) &name_tmp[name_len];
- {
- struct GNUNET_GNSRECORD_Data rd[rd_count];
- if (GNUNET_OK !=
- GNUNET_GNSRECORD_records_deserialize (rd_len,
- rd_ser_tmp,
- rd_count,
- rd))
- {
- GNUNET_break (0);
- return GNUNET_SYSERR;
- }
- }
- return GNUNET_OK;
- }
- /**
- * We've received a notification about a change to our zone.
- * Forward to monitor callback.
- *
- * @param cls the zone monitor handle
- * @param lrm the message from the service.
- */
- static void
- handle_result (void *cls,
- const struct RecordResultMessage *lrm)
- {
- struct GNUNET_NAMESTORE_ZoneMonitor *zm = cls;
- size_t name_len;
- size_t rd_len;
- unsigned rd_count;
- const char *name_tmp;
- const char *rd_ser_tmp;
- rd_len = ntohs (lrm->rd_len);
- rd_count = ntohs (lrm->rd_count);
- name_len = ntohs (lrm->name_len);
- name_tmp = (const char *) &lrm[1];
- rd_ser_tmp = (const char *) &name_tmp[name_len];
- {
- struct GNUNET_GNSRECORD_Data rd[rd_count];
- GNUNET_assert (GNUNET_OK ==
- GNUNET_GNSRECORD_records_deserialize (rd_len,
- rd_ser_tmp,
- rd_count,
- rd));
- zm->monitor (zm->monitor_cls,
- &lrm->private_key,
- name_tmp,
- rd_count,
- rd);
- }
- }
- /**
- * 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_NAMESTORE_ZoneMonitor *`
- * @param error error code
- */
- static void
- mq_error_handler (void *cls,
- enum GNUNET_MQ_Error error)
- {
- struct GNUNET_NAMESTORE_ZoneMonitor *zm = cls;
- (void) error;
- reconnect (zm);
- }
- /**
- * Reconnect to the namestore service.
- *
- * @param zm monitor to reconnect
- */
- static void
- reconnect (struct GNUNET_NAMESTORE_ZoneMonitor *zm)
- {
- struct GNUNET_MQ_MessageHandler handlers[] = {
- GNUNET_MQ_hd_fixed_size (sync,
- GNUNET_MESSAGE_TYPE_NAMESTORE_MONITOR_SYNC,
- struct GNUNET_MessageHeader,
- zm),
- GNUNET_MQ_hd_var_size (result,
- GNUNET_MESSAGE_TYPE_NAMESTORE_RECORD_RESULT,
- struct RecordResultMessage,
- zm),
- GNUNET_MQ_handler_end ()
- };
- struct GNUNET_MQ_Envelope *env;
- struct ZoneMonitorStartMessage *sm;
- if (NULL != zm->mq)
- {
- GNUNET_MQ_destroy (zm->mq);
- zm->error_cb (zm->error_cb_cls);
- }
- zm->mq = GNUNET_CLIENT_connect (zm->cfg,
- "namestore",
- handlers,
- &mq_error_handler,
- zm);
- if (NULL == zm->mq)
- return;
- env = GNUNET_MQ_msg (sm,
- GNUNET_MESSAGE_TYPE_NAMESTORE_MONITOR_START);
- sm->iterate_first = htonl (zm->iterate_first);
- sm->zone = zm->zone;
- GNUNET_MQ_send (zm->mq,
- env);
- }
- /**
- * Begin monitoring a zone for changes. If @a iterate_first is set,
- * we Will first call the @a monitor function on all existing records
- * in the selected zone(s). In any case, we will call @a sync and
- * afterwards call @a monitor whenever a record changes.
- *
- * @param cfg configuration to use to connect to namestore
- * @param zone zone to monitor
- * @param iterate_first #GNUNET_YES to first iterate over all existing records,
- * #GNUNET_NO to only return changes that happen from now on
- * @param error_cb function to call on error (i.e. disconnect); note that
- * unlike the other error callbacks in this API, a call to this
- * function does NOT destroy the monitor handle, it merely signals
- * that monitoring is down. You need to still explicitly call
- * #GNUNET_NAMESTORE_zone_monitor_stop().
- * @param error_cb_cls closure for @a error_cb
- * @param monitor function to call on zone changes
- * @param monitor_cls closure for @a monitor
- * @param sync_cb function called when we're in sync with the namestore
- * @param cls closure for @a sync_cb
- * @return handle to stop monitoring
- */
- struct GNUNET_NAMESTORE_ZoneMonitor *
- GNUNET_NAMESTORE_zone_monitor_start (const struct GNUNET_CONFIGURATION_Handle *cfg,
- const struct GNUNET_CRYPTO_EcdsaPrivateKey *zone,
- int iterate_first,
- GNUNET_SCHEDULER_TaskCallback error_cb,
- void *error_cb_cls,
- GNUNET_NAMESTORE_RecordMonitor monitor,
- void *monitor_cls,
- GNUNET_SCHEDULER_TaskCallback sync_cb,
- void *sync_cb_cls)
- {
- struct GNUNET_NAMESTORE_ZoneMonitor *zm;
- zm = GNUNET_new (struct GNUNET_NAMESTORE_ZoneMonitor);
- if (NULL != zone)
- zm->zone = *zone;
- zm->iterate_first = iterate_first;
- zm->error_cb = error_cb;
- zm->error_cb_cls = error_cb_cls;
- zm->monitor = monitor;
- zm->monitor_cls = monitor_cls;
- zm->sync_cb = sync_cb;
- zm->sync_cb_cls = sync_cb_cls;
- zm->cfg = cfg;
- reconnect (zm);
- if (NULL == zm->mq)
- {
- GNUNET_free (zm);
- return NULL;
- }
- return zm;
- }
- /**
- * Calls the monitor processor specified in #GNUNET_NAMESTORE_zone_monitor_start
- * for the next record(s). This function is used to allow clients that merely
- * monitor the NAMESTORE to still throttle namestore operations, so we can be
- * sure that the monitors can keep up.
- *
- * Note that #GNUNET_NAMESTORE_records_store() only waits for this
- * call if the previous limit set by the client was already reached.
- * Thus, by using a @a limit greater than 1, monitors basically enable
- * a queue of notifications to be processed asynchronously with some
- * delay. Note that even with a limit of 1 the
- * #GNUNET_NAMESTORE_records_store() function will run asynchronously
- * and the continuation may be invoked before the monitors completed
- * (or even started) processing the notification. Thus, monitors will
- * only closely track the current state of the namestore, but not
- * be involved in the transactions.
- *
- * @param zm the monitor
- * @param limit number of records to return to the iterator in one shot
- * (before #GNUNET_NAMESTORE_zone_monitor_next is to be called again)
- */
- void
- GNUNET_NAMESTORE_zone_monitor_next (struct GNUNET_NAMESTORE_ZoneMonitor *zm,
- uint64_t limit)
- {
- struct GNUNET_MQ_Envelope *env;
- struct ZoneMonitorNextMessage *nm;
- env = GNUNET_MQ_msg (nm,
- GNUNET_MESSAGE_TYPE_NAMESTORE_MONITOR_NEXT);
- nm->limit = GNUNET_htonll (limit);
- GNUNET_MQ_send (zm->mq,
- env);
- }
- /**
- * Stop monitoring a zone for changes.
- *
- * @param zm handle to the monitor activity to stop
- */
- void
- GNUNET_NAMESTORE_zone_monitor_stop (struct GNUNET_NAMESTORE_ZoneMonitor *zm)
- {
- if (NULL != zm->mq)
- {
- GNUNET_MQ_destroy (zm->mq);
- zm->mq = NULL;
- }
- GNUNET_free (zm);
- }
- /* end of namestore_api_monitor.c */
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