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13 Affero General Public License for more details.
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18 SPDX-License-Identifier: AGPL3.0-or-later
21 * @file namestore/namestore_api_monitor.c
22 * @brief API to monitor changes in the NAMESTORE
23 * @author Christian Grothoff
27 #include "gnunet_util_lib.h"
28 #include "gnunet_crypto_lib.h"
29 #include "gnunet_constants.h"
30 #include "gnunet_dnsparser_lib.h"
31 #include "gnunet_arm_service.h"
32 #include "gnunet_signatures.h"
33 #include "gnunet_namestore_service.h"
34 #include "namestore.h"
38 * Handle for a monitoring activity.
40 struct GNUNET_NAMESTORE_ZoneMonitor
43 * Configuration (to reconnect).
45 const struct GNUNET_CONFIGURATION_Handle *cfg;
48 * Handle to namestore service.
50 struct GNUNET_MQ_Handle *mq;
53 * Function to call on errors.
55 GNUNET_SCHEDULER_TaskCallback error_cb;
58 * Closure for @e error_cb.
63 * Function to call on events.
65 GNUNET_NAMESTORE_RecordMonitor monitor;
68 * Closure for @e monitor.
73 * Function called when we've synchronized.
75 GNUNET_SCHEDULER_TaskCallback sync_cb;
78 * Closure for @e sync_cb.
85 struct GNUNET_CRYPTO_EcdsaPrivateKey zone;
88 * Do we first iterate over all existing records?
96 * Reconnect to the namestore service.
98 * @param zm monitor to reconnect
101 reconnect (struct GNUNET_NAMESTORE_ZoneMonitor *zm);
105 * Handle SYNC message from the namestore service.
107 * @param cls the monitor
108 * @param msg the sync message
111 handle_sync (void *cls,
112 const struct GNUNET_MessageHeader *msg)
114 struct GNUNET_NAMESTORE_ZoneMonitor *zm = cls;
118 if (NULL != zm->sync_cb)
119 zm->sync_cb (zm->sync_cb_cls);
124 * We've received a notification about a change to our zone.
125 * Check that it is well-formed.
127 * @param cls the zone monitor handle
128 * @param lrm the message from the service.
131 check_result (void *cls,
132 const struct RecordResultMessage *lrm)
134 static struct GNUNET_CRYPTO_EcdsaPrivateKey zero;
135 struct GNUNET_NAMESTORE_ZoneMonitor *zm = cls;
141 const char *name_tmp;
142 const char *rd_ser_tmp;
145 if ( (0 != memcmp (&lrm->private_key,
147 sizeof (struct GNUNET_CRYPTO_EcdsaPrivateKey))) &&
150 sizeof (struct GNUNET_CRYPTO_EcdsaPrivateKey))) )
153 return GNUNET_SYSERR;
155 lrm_len = ntohs (lrm->gns_header.header.size);
156 rd_len = ntohs (lrm->rd_len);
157 rd_count = ntohs (lrm->rd_count);
158 name_len = ntohs (lrm->name_len);
159 if (name_len > MAX_NAME_LEN)
162 return GNUNET_SYSERR;
164 exp_lrm_len = sizeof (struct RecordResultMessage) + name_len + rd_len;
165 if (lrm_len != exp_lrm_len)
168 return GNUNET_SYSERR;
173 return GNUNET_SYSERR;
175 name_tmp = (const char *) &lrm[1];
176 if (name_tmp[name_len -1] != '\0')
179 return GNUNET_SYSERR;
181 rd_ser_tmp = (const char *) &name_tmp[name_len];
183 struct GNUNET_GNSRECORD_Data rd[rd_count];
186 GNUNET_GNSRECORD_records_deserialize (rd_len,
192 return GNUNET_SYSERR;
200 * We've received a notification about a change to our zone.
201 * Forward to monitor callback.
203 * @param cls the zone monitor handle
204 * @param lrm the message from the service.
207 handle_result (void *cls,
208 const struct RecordResultMessage *lrm)
210 struct GNUNET_NAMESTORE_ZoneMonitor *zm = cls;
214 const char *name_tmp;
215 const char *rd_ser_tmp;
217 rd_len = ntohs (lrm->rd_len);
218 rd_count = ntohs (lrm->rd_count);
219 name_len = ntohs (lrm->name_len);
220 name_tmp = (const char *) &lrm[1];
221 rd_ser_tmp = (const char *) &name_tmp[name_len];
223 struct GNUNET_GNSRECORD_Data rd[rd_count];
225 GNUNET_assert (GNUNET_OK ==
226 GNUNET_GNSRECORD_records_deserialize (rd_len,
230 zm->monitor (zm->monitor_cls,
240 * Generic error handler, called with the appropriate error code and
241 * the same closure specified at the creation of the message queue.
242 * Not every message queue implementation supports an error handler.
244 * @param cls closure with the `struct GNUNET_NAMESTORE_ZoneMonitor *`
245 * @param error error code
248 mq_error_handler (void *cls,
249 enum GNUNET_MQ_Error error)
251 struct GNUNET_NAMESTORE_ZoneMonitor *zm = cls;
259 * Reconnect to the namestore service.
261 * @param zm monitor to reconnect
264 reconnect (struct GNUNET_NAMESTORE_ZoneMonitor *zm)
266 struct GNUNET_MQ_MessageHandler handlers[] = {
267 GNUNET_MQ_hd_fixed_size (sync,
268 GNUNET_MESSAGE_TYPE_NAMESTORE_MONITOR_SYNC,
269 struct GNUNET_MessageHeader,
271 GNUNET_MQ_hd_var_size (result,
272 GNUNET_MESSAGE_TYPE_NAMESTORE_RECORD_RESULT,
273 struct RecordResultMessage,
275 GNUNET_MQ_handler_end ()
277 struct GNUNET_MQ_Envelope *env;
278 struct ZoneMonitorStartMessage *sm;
282 GNUNET_MQ_destroy (zm->mq);
283 zm->error_cb (zm->error_cb_cls);
285 zm->mq = GNUNET_CLIENT_connect (zm->cfg,
292 env = GNUNET_MQ_msg (sm,
293 GNUNET_MESSAGE_TYPE_NAMESTORE_MONITOR_START);
294 sm->iterate_first = htonl (zm->iterate_first);
296 GNUNET_MQ_send (zm->mq,
302 * Begin monitoring a zone for changes. If @a iterate_first is set,
303 * we Will first call the @a monitor function on all existing records
304 * in the selected zone(s). In any case, we will call @a sync and
305 * afterwards call @a monitor whenever a record changes.
307 * @param cfg configuration to use to connect to namestore
308 * @param zone zone to monitor
309 * @param iterate_first #GNUNET_YES to first iterate over all existing records,
310 * #GNUNET_NO to only return changes that happen from now on
311 * @param error_cb function to call on error (i.e. disconnect); note that
312 * unlike the other error callbacks in this API, a call to this
313 * function does NOT destroy the monitor handle, it merely signals
314 * that monitoring is down. You need to still explicitly call
315 * #GNUNET_NAMESTORE_zone_monitor_stop().
316 * @param error_cb_cls closure for @a error_cb
317 * @param monitor function to call on zone changes
318 * @param monitor_cls closure for @a monitor
319 * @param sync_cb function called when we're in sync with the namestore
320 * @param cls closure for @a sync_cb
321 * @return handle to stop monitoring
323 struct GNUNET_NAMESTORE_ZoneMonitor *
324 GNUNET_NAMESTORE_zone_monitor_start (const struct GNUNET_CONFIGURATION_Handle *cfg,
325 const struct GNUNET_CRYPTO_EcdsaPrivateKey *zone,
327 GNUNET_SCHEDULER_TaskCallback error_cb,
329 GNUNET_NAMESTORE_RecordMonitor monitor,
331 GNUNET_SCHEDULER_TaskCallback sync_cb,
334 struct GNUNET_NAMESTORE_ZoneMonitor *zm;
336 zm = GNUNET_new (struct GNUNET_NAMESTORE_ZoneMonitor);
339 zm->iterate_first = iterate_first;
340 zm->error_cb = error_cb;
341 zm->error_cb_cls = error_cb_cls;
342 zm->monitor = monitor;
343 zm->monitor_cls = monitor_cls;
344 zm->sync_cb = sync_cb;
345 zm->sync_cb_cls = sync_cb_cls;
358 * Calls the monitor processor specified in #GNUNET_NAMESTORE_zone_monitor_start
359 * for the next record(s). This function is used to allow clients that merely
360 * monitor the NAMESTORE to still throttle namestore operations, so we can be
361 * sure that the monitors can keep up.
363 * Note that #GNUNET_NAMESTORE_records_store() only waits for this
364 * call if the previous limit set by the client was already reached.
365 * Thus, by using a @a limit greater than 1, monitors basically enable
366 * a queue of notifications to be processed asynchronously with some
367 * delay. Note that even with a limit of 1 the
368 * #GNUNET_NAMESTORE_records_store() function will run asynchronously
369 * and the continuation may be invoked before the monitors completed
370 * (or even started) processing the notification. Thus, monitors will
371 * only closely track the current state of the namestore, but not
372 * be involved in the transactions.
374 * @param zm the monitor
375 * @param limit number of records to return to the iterator in one shot
376 * (before #GNUNET_NAMESTORE_zone_monitor_next is to be called again)
379 GNUNET_NAMESTORE_zone_monitor_next (struct GNUNET_NAMESTORE_ZoneMonitor *zm,
382 struct GNUNET_MQ_Envelope *env;
383 struct ZoneMonitorNextMessage *nm;
385 env = GNUNET_MQ_msg (nm,
386 GNUNET_MESSAGE_TYPE_NAMESTORE_MONITOR_NEXT);
387 nm->limit = GNUNET_htonll (limit);
388 GNUNET_MQ_send (zm->mq,
394 * Stop monitoring a zone for changes.
396 * @param zm handle to the monitor activity to stop
399 GNUNET_NAMESTORE_zone_monitor_stop (struct GNUNET_NAMESTORE_ZoneMonitor *zm)
403 GNUNET_MQ_destroy (zm->mq);
409 /* end of namestore_api_monitor.c */