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20 * @file rps/gnunet-service-rps_sampler.c
21 * @brief sampler implementation
22 * @author Julius Bünger
25 #include "gnunet_util_lib.h"
26 #include "gnunet_statistics_service.h"
29 #include "rps-sampler_common.h"
30 #include "gnunet-service-rps_sampler.h"
31 #include "gnunet-service-rps_sampler_elem.h"
36 #include "rps-test_util.h"
38 #define LOG(kind, ...) GNUNET_log_from(kind,"rps-sampler",__VA_ARGS__)
41 // multiple 'clients'?
43 // TODO check for overflows
45 // TODO align message structs
47 // hist_size_init, hist_size_max
49 /***********************************************************************
50 * WARNING: This section needs to be reviewed regarding the use of
51 * functions providing (pseudo)randomness!
52 ***********************************************************************/
54 // TODO care about invalid input of the caller (size 0 or less...)
57 * @brief Callback called each time a new peer was put into the sampler
59 * @param cls A possibly given closure
62 (*SamplerNotifyUpdateCB) (void *cls);
65 * @brief Context for a callback. Contains callback and closure.
67 * Meant to be an entry in an DLL.
69 struct SamplerNotifyUpdateCTX
72 * @brief The Callback to call on updates
74 SamplerNotifyUpdateCB notify_cb;
77 * @brief The according closure.
82 * @brief Next element in DLL.
84 struct SamplerNotifyUpdateCTX *next;
87 * @brief Previous element in DLL.
89 struct SamplerNotifyUpdateCTX *prev;
94 * Type of function used to differentiate between modified and not modified
98 (*RPS_get_peers_type) (void *cls);
102 * Get one random peer out of the sampled peers.
104 * We might want to reinitialise this sampler after giving the
105 * corrsponding peer to the client.
108 sampler_mod_get_rand_peer (void *cls);
112 * Closure to _get_n_rand_peers_ready_cb()
114 struct RPS_SamplerRequestHandle
119 struct RPS_SamplerRequestHandle *next;
120 struct RPS_SamplerRequestHandle *prev;
123 * Number of peers we are waiting for.
128 * Number of peers we currently have.
130 uint32_t cur_num_peers;
133 * Pointer to the array holding the ids.
135 struct GNUNET_PeerIdentity *ids;
138 * Head and tail for the DLL to store the tasks for single requests
140 struct GetPeerCls *gpc_head;
141 struct GetPeerCls *gpc_tail;
146 struct RPS_Sampler *sampler;
149 * Callback to be called when all ids are available.
151 RPS_sampler_n_rand_peers_ready_cb callback;
154 * Closure given to the callback
160 // * Global sampler variable.
162 //struct RPS_Sampler *sampler;
166 * The minimal size for the extended sampler elements.
168 static size_t min_size;
171 * The maximal size the extended sampler elements should grow to.
173 static size_t max_size;
176 * The size the extended sampler elements currently have.
178 //static size_t extra_size;
181 * Inedex to the sampler element that is the next to be returned
183 static uint32_t client_get_index;
187 * Initialise a modified tuple of sampler elements.
189 * @param init_size the size the sampler is initialised with
190 * @param max_round_interval maximum time a round takes
191 * @return a handle to a sampler that consists of sampler elements.
194 RPS_sampler_mod_init (size_t init_size,
195 struct GNUNET_TIME_Relative max_round_interval)
197 struct RPS_Sampler *sampler;
199 /* Initialise context around extended sampler */
200 min_size = 10; // TODO make input to _samplers_init()
201 max_size = 1000; // TODO make input to _samplers_init()
203 sampler = GNUNET_new (struct RPS_Sampler);
204 sampler->max_round_interval = max_round_interval;
205 sampler->get_peers = sampler_mod_get_rand_peer;
206 //sampler->sampler_elements = GNUNET_new_array(init_size, struct GNUNET_PeerIdentity);
207 //GNUNET_array_grow (sampler->sampler_elements, sampler->sampler_size, min_size);
208 RPS_sampler_resize (sampler, init_size);
210 client_get_index = 0;
212 //GNUNET_assert (init_size == sampler->sampler_size);
215 sampler->file_name = create_file ("sampler-");
217 LOG (GNUNET_ERROR_TYPE_DEBUG,
218 "Initialised modified sampler %s\n",
220 to_file (sampler->file_name,
221 "This is a modified sampler");
229 * Get one random peer out of the sampled peers.
231 * This reinitialises the queried sampler element.
234 sampler_mod_get_rand_peer (void *cls)
236 struct GetPeerCls *gpc = cls;
237 struct RPS_SamplerElement *s_elem;
238 struct GNUNET_TIME_Relative last_request_diff;
239 struct RPS_Sampler *sampler;
241 gpc->get_peer_task = NULL;
242 gpc->notify_ctx = NULL;
243 sampler = gpc->req_handle->sampler;
245 LOG (GNUNET_ERROR_TYPE_DEBUG, "Single peer was requested\n");
247 /* Cycle the #client_get_index one step further */
248 client_get_index = (client_get_index + 1) % sampler->sampler_size;
250 s_elem = sampler->sampler_elements[client_get_index];
251 *gpc->id = s_elem->peer_id;
252 GNUNET_assert (NULL != s_elem);
254 if (EMPTY == s_elem->is_empty)
256 LOG (GNUNET_ERROR_TYPE_DEBUG,
257 "Sampler_mod element empty, rescheduling.\n");
258 GNUNET_assert (NULL == gpc->notify_ctx);
260 sampler_notify_on_update (sampler,
261 &sampler_mod_get_rand_peer,
266 /* Check whether we may use this sampler to give it back to the client */
267 if (GNUNET_TIME_UNIT_FOREVER_ABS.abs_value_us != s_elem->last_client_request.abs_value_us)
269 // TODO remove this condition at least for the client sampler
271 GNUNET_TIME_absolute_get_difference (s_elem->last_client_request,
272 GNUNET_TIME_absolute_get ());
273 /* We're not going to give it back now if it was
274 * already requested by a client this round */
275 if (last_request_diff.rel_value_us < sampler->max_round_interval.rel_value_us)
277 LOG (GNUNET_ERROR_TYPE_DEBUG,
278 "Last client request on this sampler was less than max round interval ago -- scheduling for later\n");
279 ///* How many time remains untile the next round has started? */
280 //inv_last_request_diff =
281 // GNUNET_TIME_absolute_get_difference (last_request_diff,
282 // sampler->max_round_interval);
283 // add a little delay
284 /* Schedule it one round later */
285 GNUNET_assert (NULL == gpc->notify_ctx);
287 sampler_notify_on_update (sampler,
288 &sampler_mod_get_rand_peer,
293 if (2 > s_elem->num_peers)
295 LOG (GNUNET_ERROR_TYPE_DEBUG,
296 "This s_elem saw less than two peers -- scheduling for later\n");
297 GNUNET_assert (NULL == gpc->notify_ctx);
299 sampler_notify_on_update (sampler,
300 &sampler_mod_get_rand_peer,
304 /* More reasons to wait could be added here */
306 // GNUNET_STATISTICS_set (stats,
307 // "# client sampler element input",
308 // s_elem->num_peers,
310 // GNUNET_STATISTICS_set (stats,
311 // "# client sampler element change",
312 // s_elem->num_change,
315 RPS_sampler_elem_reinit (s_elem);
316 s_elem->last_client_request = GNUNET_TIME_absolute_get ();
318 GNUNET_CONTAINER_DLL_remove (gpc->req_handle->gpc_head,
319 gpc->req_handle->gpc_tail,
321 gpc->cont (gpc->cont_cls, gpc->id);
326 /* end of gnunet-service-rps.c */