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22 * @file rps/gnunet-service-rps_sampler.c
23 * @brief sampler implementation
24 * @author Julius Bünger
27 #include "gnunet_util_lib.h"
30 #include "gnunet-service-rps_sampler.h"
35 #define LOG(kind, ...) GNUNET_log(kind, __VA_ARGS__)
37 // multiple 'clients'?
39 // TODO check for overflows
41 // TODO align message structs
43 // hist_size_init, hist_size_max
45 /***********************************************************************
46 * WARNING: This section needs to be reviewed regarding the use of
47 * functions providing (pseudo)randomness!
48 ***********************************************************************/
50 // TODO care about invalid input of the caller (size 0 or less...)
59 * A sampler element sampling one PeerID at a time.
61 struct RPS_SamplerElement
64 * Min-wise linear permutation used by this sampler.
66 * This is an key later used by a hmac.
68 struct GNUNET_CRYPTO_AuthKey auth_key;
71 * The PeerID this sampler currently samples.
73 struct GNUNET_PeerIdentity peer_id;
76 * The according hash value of this PeerID.
78 struct GNUNET_HashCode peer_id_hash;
81 * Time of last request.
83 struct GNUNET_TIME_Absolute last_request;
86 * Flag that indicates that we are not holding a valid PeerID right now.
88 enum RPS_SamplerEmpty is_empty;
92 * Sampler with its own array of SamplerElements
97 * Number of sampler elements we hold.
99 unsigned int sampler_size;
103 * All Samplers in one array.
105 struct RPS_SamplerElement **sampler_elements;
108 * Index to a sampler element.
110 * Gets cycled on every hist_request.
112 uint64_t sampler_elem_index;
115 * Callback to be called when a peer gets inserted into a sampler.
117 RPS_sampler_insert_cb insert_cb;
120 * Closure to the insert_cb.
125 * Callback to be called when a peer gets inserted into a sampler.
127 RPS_sampler_remove_cb remove_cb;
130 * Closure to the remove_cb.
136 * Global sampler variable.
138 struct RPS_Sampler *sampler;
142 * The minimal size for the extended sampler elements.
144 static size_t min_size;
147 * The maximal size the extended sampler elements should grow to.
149 static size_t max_size;
152 * The size the extended sampler elements currently have.
154 //static size_t extra_size;
157 * Inedex to the sampler element that is the next to be returned
159 static uint64_t extended_samplers_index;
164 * Only needed in the beginning to check how many of the 64 deltas
167 static unsigned int req_counter;
170 * Time of the last request we received.
172 * Used to compute the expected request rate.
174 static struct GNUNET_TIME_Absolute last_request;
177 * Last 64 deltas between requests
179 static struct GNUNET_TIME_Relative request_deltas[64];
182 * The prediction of the rate of requests
184 static struct GNUNET_TIME_Relative request_rate;
188 * Sum all time relatives of an array.
190 struct GNUNET_TIME_Relative
191 T_relative_sum (const struct GNUNET_TIME_Relative *rel_array, uint64_t arr_size)
193 struct GNUNET_TIME_Relative sum;
196 sum = GNUNET_TIME_UNIT_ZERO;
197 for ( i = 0 ; i < arr_size ; i++ )
199 sum = GNUNET_TIME_relative_add (sum, rel_array[i]);
205 * Compute the average of given time relatives.
207 struct GNUNET_TIME_Relative
208 T_relative_avg (const struct GNUNET_TIME_Relative *rel_array, uint64_t arr_size)
210 return T_relative_sum (rel_array, arr_size); // FIXME find a way to devide that by arr_size
216 * Reinitialise a previously initialised sampler element.
218 * @param sampler pointer to the memory that keeps the value.
221 RPS_sampler_elem_reinit (struct RPS_SamplerElement *sampler_el)
223 sampler_el->is_empty = EMPTY;
225 // I guess I don't need to call GNUNET_CRYPTO_hmac_derive_key()...
226 GNUNET_CRYPTO_random_block(GNUNET_CRYPTO_QUALITY_STRONG,
227 &(sampler_el->auth_key.key),
228 GNUNET_CRYPTO_HASH_LENGTH);
230 sampler_el->last_request = GNUNET_TIME_UNIT_FOREVER_ABS;
232 /* We might want to keep the previous peer */
234 //GNUNET_CRYPTO_hmac(&sampler_el->auth_key, sampler_el->peer_id,
235 // sizeof(struct GNUNET_PeerIdentity),
236 // &sampler_el->peer_id_hash);
241 * (Re)Initialise given Sampler with random min-wise independent function.
243 * In this implementation this means choosing an auth_key for later use in
246 * @return a newly created RPS_SamplerElement which currently holds no id.
248 struct RPS_SamplerElement *
249 RPS_sampler_elem_create (void)
251 struct RPS_SamplerElement *s;
253 s = GNUNET_new (struct RPS_SamplerElement);
255 RPS_sampler_elem_reinit (s);
256 LOG (GNUNET_ERROR_TYPE_DEBUG, "SAMPLER: initialised with empty PeerID\n");
263 * Input an PeerID into the given sampler.
266 RPS_sampler_elem_next (struct RPS_SamplerElement *s_elem, const struct GNUNET_PeerIdentity *other,
267 RPS_sampler_insert_cb insert_cb, void *insert_cls,
268 RPS_sampler_remove_cb remove_cb, void *remove_cls)
270 struct GNUNET_HashCode other_hash;
272 if ( 0 == GNUNET_CRYPTO_cmp_peer_identity(other, &(s_elem->peer_id)) )
274 LOG(GNUNET_ERROR_TYPE_DEBUG, "SAMPLER: Got PeerID %s\n",
276 LOG(GNUNET_ERROR_TYPE_DEBUG, "SAMPLER: Have already PeerID %s\n",
277 GNUNET_i2s(&(s_elem->peer_id)));
281 GNUNET_CRYPTO_hmac(&s_elem->auth_key,
283 sizeof(struct GNUNET_PeerIdentity),
286 if ( EMPTY == s_elem->is_empty )
287 { // Or whatever is a valid way to say
288 // "we have no PeerID at the moment"
289 LOG(GNUNET_ERROR_TYPE_DEBUG, "SAMPLER: Got PeerID %s; Simply accepting (was empty previously).\n",
291 s_elem->peer_id = *other;
292 //s_elem->peer_id = other;
293 s_elem->peer_id_hash = other_hash;
294 if (NULL != sampler->insert_cb)
296 sampler->insert_cb(sampler->insert_cls, &(s_elem->peer_id));
299 else if ( 0 > GNUNET_CRYPTO_hash_cmp(&other_hash, &s_elem->peer_id_hash) )
301 LOG(GNUNET_ERROR_TYPE_DEBUG, "SAMPLER: Got PeerID %s\n",
303 LOG(GNUNET_ERROR_TYPE_DEBUG, "SAMPLER: Discarding old PeerID %s\n",
304 GNUNET_i2s(&s_elem->peer_id));
306 if ( NULL != sampler->remove_cb )
308 LOG(GNUNET_ERROR_TYPE_DEBUG, "SAMPLER: Removing old PeerID %s with the remove callback.\n",
309 GNUNET_i2s(&s_elem->peer_id));
310 sampler->remove_cb(sampler->remove_cls, &s_elem->peer_id);
313 memcpy(&s_elem->peer_id, other, sizeof(struct GNUNET_PeerIdentity));
314 //s_elem->peer_id = other;
315 s_elem->peer_id_hash = other_hash;
317 if ( NULL != sampler->insert_cb )
319 LOG(GNUNET_ERROR_TYPE_DEBUG, "SAMPLER: Inserting new PeerID %s with the insert callback.\n",
320 GNUNET_i2s(&s_elem->peer_id));
321 sampler->insert_cb(sampler->insert_cls, &s_elem->peer_id);
326 LOG(GNUNET_ERROR_TYPE_DEBUG, "SAMPLER: Got PeerID %s\n",
328 LOG(GNUNET_ERROR_TYPE_DEBUG, "SAMPLER: Keeping old PeerID %s\n",
329 GNUNET_i2s(&s_elem->peer_id));
332 s_elem->is_empty = NOT_EMPTY;
337 * Grow or shrink the size of the sampler.
339 * @param new_size the new size of the sampler
342 RPS_sampler_resize (unsigned int new_size)
344 unsigned int old_size;
346 struct RPS_SamplerElement **rem_list;
348 // TODO check min and max size
350 old_size = sampler->sampler_size;
352 if (old_size > new_size)
354 /* Temporary store those to properly call the removeCB on those later */
355 rem_list = GNUNET_malloc ((old_size - new_size) * sizeof (struct RPS_SamplerElement *));
357 &sampler->sampler_elements[new_size],
358 (old_size - new_size) * sizeof (struct RPS_SamplerElement *));
360 LOG (GNUNET_ERROR_TYPE_DEBUG, "SAMPLER: Shrinking sampler %d -> %d\n", old_size, new_size);
361 GNUNET_array_grow (sampler->sampler_elements, sampler->sampler_size, new_size);
362 LOG (GNUNET_ERROR_TYPE_DEBUG,
363 "SAMPLER: sampler->sampler_elements now points to %p\n",
364 sampler->sampler_elements);
366 for (i = 0 ; i < old_size - new_size ; i++)
367 {/* Remove unneeded rest */
368 LOG (GNUNET_ERROR_TYPE_DEBUG, "SAMPLER: Removing %" PRIX64 ". sampler\n", i);
369 if (NULL != sampler->remove_cb)
370 sampler->remove_cb (sampler->remove_cls, &rem_list[i]->peer_id);
371 GNUNET_free (rem_list[i]);
374 else if (old_size < new_size)
376 LOG (GNUNET_ERROR_TYPE_DEBUG, "SAMPLER: Growing sampler %d -> %d\n", old_size, new_size);
377 GNUNET_array_grow (sampler->sampler_elements, sampler->sampler_size, new_size);
378 LOG (GNUNET_ERROR_TYPE_DEBUG,
379 "SAMPLER: sampler->sampler_elements now points to %p\n",
380 sampler->sampler_elements);
382 for ( i = old_size ; i < new_size ; i++ )
383 { /* Add new sampler elements */
384 sampler->sampler_elements[i] = RPS_sampler_elem_create ();
385 if (NULL != sampler->insert_cb)
386 sampler->insert_cb (sampler->insert_cls, &sampler->sampler_elements[i]->peer_id);
387 LOG (GNUNET_ERROR_TYPE_DEBUG,
388 "SAMPLER: Added %" PRIX64 ". sampler, now pointing to %p, contains %s\n",
389 i, &sampler->sampler_elements[i], GNUNET_i2s (&sampler->sampler_elements[i]->peer_id));
394 LOG (GNUNET_ERROR_TYPE_DEBUG, "SAMPLER: Size remains the same -- nothing to do\n");
398 GNUNET_assert(sampler->sampler_size == new_size);
399 LOG(GNUNET_ERROR_TYPE_DEBUG, "SAMPLER: Finished growing/shrinking.\n"); // remove
404 * Initialise a tuple of sampler elements.
406 * @param init_size the size the sampler is initialised with
407 * @param id with which all newly created sampler elements are initialised
408 * @param ins_cb the callback that will be called on every PeerID that is
409 * newly inserted into a sampler element
410 * @param ins_cls the closure given to #ins_cb
411 * @param rem_cb the callback that will be called on every PeerID that is
412 * removed from a sampler element
413 * @param rem_cls the closure given to #rem_cb
416 RPS_sampler_init (size_t init_size, const struct GNUNET_PeerIdentity *id,
417 RPS_sampler_insert_cb ins_cb, void *ins_cls,
418 RPS_sampler_remove_cb rem_cb, void *rem_cls)
420 //struct RPS_Sampler *sampler;
423 /* Initialise context around extended sampler */
424 min_size = 10; // TODO make input to _samplers_init()
425 max_size = 1000; // TODO make input to _samplers_init()
426 GNUNET_new_array (64, struct GNUNET_TIME_Relative);
428 sampler = GNUNET_new (struct RPS_Sampler);
429 sampler->sampler_size = 0;
430 sampler->sampler_elements = NULL;
431 sampler->insert_cb = ins_cb;
432 sampler->insert_cls = ins_cls;
433 sampler->remove_cb = rem_cb;
434 sampler->remove_cls = rem_cls;
435 //sampler->sampler_elements = GNUNET_new_array(init_size, struct GNUNET_PeerIdentity);
436 //GNUNET_array_grow (sampler->sampler_elements, sampler->sampler_size, min_size);
437 RPS_sampler_resize (init_size);
438 RPS_sampler_update_list (id); // no super nice desing but ok for the moment
440 extended_samplers_index = 0;
442 //GNUNET_assert (init_size == sampler->sampler_size);
447 * A fuction to update every sampler in the given list
449 * @param id the PeerID that is put in the sampler
452 RPS_sampler_update_list (const struct GNUNET_PeerIdentity *id)
456 for ( i = 0 ; i < sampler->sampler_size ; i++ )
457 RPS_sampler_elem_next (sampler->sampler_elements[i], id,
458 sampler->insert_cb, sampler->insert_cls,
459 sampler->remove_cb, sampler->remove_cls);
464 * Reinitialise all previously initialised sampler elements with the given value.
466 * Used to get rid of a PeerID.
468 * @param id the id of the sampler elements to update.
471 RPS_sampler_reinitialise_by_value (const struct GNUNET_PeerIdentity *id)
475 for ( i = 0 ; i < sampler->sampler_size ; i++ )
477 if ( 0 == GNUNET_CRYPTO_cmp_peer_identity(id, &(sampler->sampler_elements[i]->peer_id)) )
479 LOG(GNUNET_ERROR_TYPE_DEBUG, "SAMPLER: Reinitialising sampler\n");
480 RPS_sampler_elem_reinit (sampler->sampler_elements[i]);
487 * Get one random peer out of the sampled peers.
489 * We might want to reinitialise this sampler after giving the
490 * corrsponding peer to the client.
491 * Only used internally
493 const struct GNUNET_PeerIdentity *
494 RPS_sampler_get_rand_peer_ ()
497 const struct GNUNET_PeerIdentity *peer; // do we have to malloc that?
499 // TODO implement extra logic
502 * Choose the r_index of the peer we want to return
503 * at random from the interval of the gossip list
505 r_index = GNUNET_CRYPTO_random_u64(GNUNET_CRYPTO_QUALITY_STRONG,
506 sampler->sampler_size);
508 //if ( EMPTY == sampler->sampler_elements[r_index]->is_empty )
509 // // TODO schedule for later
512 peer = &(sampler->sampler_elements[r_index]->peer_id);
513 sampler->sampler_elements[r_index]->last_request = GNUNET_TIME_absolute_get();
514 LOG(GNUNET_ERROR_TYPE_DEBUG, "Sgrp: Returning PeerID %s\n", GNUNET_i2s(peer));
520 * Get n random peers out of the sampled peers.
522 * We might want to reinitialise this sampler after giving the
523 * corrsponding peer to the client.
524 * Random with or without consumption?
525 * Only used internally
527 const struct GNUNET_PeerIdentity *
528 RPS_sampler_get_n_rand_peers_ (uint64_t n)
530 if ( 0 == sampler->sampler_size )
532 LOG (GNUNET_ERROR_TYPE_DEBUG,
533 "Sgrp: List empty - Returning NULL\n");
538 // TODO check if we have too much (distinct) sampled peers
539 // If we are not ready yet maybe schedule for later
540 struct GNUNET_PeerIdentity *peers;
543 peers = GNUNET_malloc (n * sizeof(struct GNUNET_PeerIdentity));
545 for ( i = 0 ; i < n ; i++ ) {
546 //peers[i] = RPS_sampler_get_rand_peer_(sampler->sampler_elements);
547 memcpy (&peers[i], RPS_sampler_get_rand_peer_ (), sizeof (struct GNUNET_PeerIdentity));
555 * Get one random peer out of the sampled peers.
557 * We might want to reinitialise this sampler after giving the
558 * corrsponding peer to the client.
560 * @return a random PeerID of the PeerIDs previously put into the sampler.
562 const struct GNUNET_PeerIdentity *
563 RPS_sampler_get_rand_peer ()
565 struct GNUNET_PeerIdentity *peer;
567 if (64 > req_counter)
571 memcpy (&request_deltas[1],
573 (req_counter - 1) * sizeof (struct GNUNET_TIME_Relative));
574 request_deltas[0] = GNUNET_TIME_absolute_get_difference (last_request,
575 GNUNET_TIME_absolute_get ());
576 request_rate = T_relative_avg (request_deltas, req_counter);
578 last_request = GNUNET_TIME_absolute_get();
579 // TODO resize the size of the extended_samplers
581 // use _get_rand_peer_ ?
582 peer = GNUNET_new (struct GNUNET_PeerIdentity);
583 *peer = sampler->sampler_elements[extended_samplers_index]->peer_id;
584 RPS_sampler_elem_reinit (sampler->sampler_elements[extended_samplers_index]);
585 if ( extended_samplers_index == sampler->sampler_size )
586 extended_samplers_index = 0;
588 extended_samplers_index++;
594 * Get n random peers out of the sampled peers.
596 * We might want to reinitialise this sampler after giving the
597 * corrsponding peer to the client.
598 * Random with or without consumption?
600 * @return n random PeerIDs of the PeerIDs previously put into the sampler.
602 const struct GNUNET_PeerIdentity *
603 RPS_sampler_get_n_rand_peers (uint64_t n)
605 // use _get_rand_peers_ ?
606 if ( 0 == sampler->sampler_size )
608 LOG (GNUNET_ERROR_TYPE_DEBUG,
609 "Sgrp: List empty - Returning NULL\n");
614 // TODO check if we have too much (distinct) sampled peers
615 // If we are not ready yet maybe schedule for later
616 struct GNUNET_PeerIdentity *peers;
617 const struct GNUNET_PeerIdentity *peer;
620 peers = GNUNET_malloc (n * sizeof (struct GNUNET_PeerIdentity));
622 for ( i = 0 ; i < n ; i++ ) {
623 //peers[i] = RPS_sampler_get_rand_peer_(sampler->sampler_elements);
624 peer = RPS_sampler_get_rand_peer ();
625 memcpy (&peers[i], peer, sizeof (struct GNUNET_PeerIdentity));
626 //GNUNET_free (peer);
634 * Counts how many Samplers currently hold a given PeerID.
636 * @param id the PeerID to count.
638 * @return the number of occurrences of id.
641 RPS_sampler_count_id (const struct GNUNET_PeerIdentity *id)
647 for ( i = 0 ; i < sampler->sampler_size ; i++ )
649 if ( 0 == GNUNET_CRYPTO_cmp_peer_identity (&sampler->sampler_elements[i]->peer_id, id)
650 && EMPTY != sampler->sampler_elements[i]->is_empty)
658 * Cleans the sampler.
661 RPS_sampler_destroy ()
663 RPS_sampler_resize (0);
664 GNUNET_free (request_deltas); // _array_grow()?
665 GNUNET_array_grow (sampler->sampler_elements, sampler->sampler_size, 0);
668 /* end of gnunet-service-rps.c */