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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_from(kind,"rps-sampler",__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;
82 * Time of last request.
84 struct GNUNET_TIME_Absolute last_client_request;
87 * Flag that indicates that we are not holding a valid PeerID right now.
89 enum RPS_SamplerEmpty is_empty;
94 struct GNUNET_TIME_Absolute birth;
97 * How many times a PeerID was put in this sampler.
102 * How many times this sampler changed the peer_id.
109 * Sampler with its own array of SamplerElements
114 * Number of sampler elements we hold.
116 unsigned int sampler_size;
120 * All Samplers in one array.
122 struct RPS_SamplerElement **sampler_elements;
125 * Max time a round takes
127 * Used in the context of RPS
129 struct GNUNET_TIME_Relative max_round_interval;
133 * Closure to _get_n_rand_peers_ready_cb()
135 struct NRandPeersReadyCls
138 * Number of peers we are waiting for.
143 * Number of peers we currently have.
145 uint32_t cur_num_peers;
148 * Pointer to the array holding the ids.
150 struct GNUNET_PeerIdentity *ids;
153 * Callback to be called when all ids are available.
155 RPS_sampler_n_rand_peers_ready_cb callback;
158 * Closure given to the callback
164 * Callback that is called from _get_rand_peer() when the PeerID is ready.
166 * @param cls the closure given alongside this function.
167 * @param id the PeerID that was returned
170 (*RPS_sampler_rand_peer_ready_cont) (void *cls,
171 const struct GNUNET_PeerIdentity *id);
174 * Closure to #RPS_sampler_get_rand_peer()
179 struct GetPeerCls *next;
180 struct GetPeerCls *prev;
183 * The sampler this function operates on.
185 struct RPS_Sampler *sampler;
188 * The task for this function.
190 struct GNUNET_SCHEDULER_Task *get_peer_task;
195 RPS_sampler_rand_peer_ready_cont cont;
198 * The closure to the callback
203 * The address of the id to be stored at
205 struct GNUNET_PeerIdentity *id;
210 // * Global sampler variable.
212 //struct RPS_Sampler *sampler;
216 * The minimal size for the extended sampler elements.
218 static size_t min_size;
221 * The maximal size the extended sampler elements should grow to.
223 static size_t max_size;
226 * The size the extended sampler elements currently have.
228 //static size_t extra_size;
231 * Inedex to the sampler element that is the next to be returned
233 static uint32_t client_get_index;
236 /** FIXME document */
237 struct GetPeerCls *gpc_head;
238 struct GetPeerCls *gpc_tail;
242 * Callback to _get_rand_peer() used by _get_n_rand_peers().
244 * Checks whether all n peers are available. If they are,
248 check_n_peers_ready (void *cls,
249 const struct GNUNET_PeerIdentity *id)
251 struct NRandPeersReadyCls *n_peers_cls;
253 n_peers_cls = (struct NRandPeersReadyCls *) cls;
255 n_peers_cls->cur_num_peers++;
256 LOG (GNUNET_ERROR_TYPE_DEBUG,
257 "Got %" PRIX32 ". of %" PRIX32 " peers\n",
258 n_peers_cls->cur_num_peers, n_peers_cls->num_peers);
260 if (n_peers_cls->num_peers == n_peers_cls->cur_num_peers)
261 { /* All peers are ready -- return those to the client */
262 GNUNET_assert (NULL != n_peers_cls->callback);
264 LOG (GNUNET_ERROR_TYPE_DEBUG,
265 "returning %" PRIX32 " peers to the client\n",
266 n_peers_cls->num_peers);
267 n_peers_cls->callback (n_peers_cls->cls, n_peers_cls->ids, n_peers_cls->num_peers);
269 GNUNET_free (n_peers_cls);
275 * Reinitialise a previously initialised sampler element.
277 * @param sampler pointer to the memory that keeps the value.
280 RPS_sampler_elem_reinit (struct RPS_SamplerElement *sampler_el)
282 sampler_el->is_empty = EMPTY;
284 // I guess I don't need to call GNUNET_CRYPTO_hmac_derive_key()...
285 GNUNET_CRYPTO_random_block(GNUNET_CRYPTO_QUALITY_STRONG,
286 &(sampler_el->auth_key.key),
287 GNUNET_CRYPTO_HASH_LENGTH);
289 sampler_el->last_client_request = GNUNET_TIME_UNIT_FOREVER_ABS;
291 sampler_el->birth = GNUNET_TIME_absolute_get ();
292 sampler_el->num_peers = 0;
293 sampler_el->num_change = 0;
298 * (Re)Initialise given Sampler with random min-wise independent function.
300 * In this implementation this means choosing an auth_key for later use in
303 * @return a newly created RPS_SamplerElement which currently holds no id.
305 struct RPS_SamplerElement *
306 RPS_sampler_elem_create (void)
308 struct RPS_SamplerElement *s;
310 s = GNUNET_new (struct RPS_SamplerElement);
312 RPS_sampler_elem_reinit (s);
313 LOG (GNUNET_ERROR_TYPE_DEBUG, "initialised with empty PeerID\n");
320 * Input an PeerID into the given sampler element.
322 * @param sampler the sampler the @a s_elem belongs to.
326 RPS_sampler_elem_next (struct RPS_SamplerElement *s_elem,
327 struct RPS_Sampler *sampler,
328 const struct GNUNET_PeerIdentity *other)
330 struct GNUNET_HashCode other_hash;
334 if (0 == GNUNET_CRYPTO_cmp_peer_identity (other, &(s_elem->peer_id)))
336 LOG (GNUNET_ERROR_TYPE_DEBUG, " Got PeerID %s\n",
338 LOG (GNUNET_ERROR_TYPE_DEBUG, "Have already PeerID %s\n",
339 GNUNET_i2s (&(s_elem->peer_id)));
343 GNUNET_CRYPTO_hmac(&s_elem->auth_key,
345 sizeof(struct GNUNET_PeerIdentity),
348 if (EMPTY == s_elem->is_empty)
350 LOG (GNUNET_ERROR_TYPE_DEBUG,
351 "Got PeerID %s; Simply accepting (was empty previously).\n",
353 s_elem->peer_id = *other;
354 s_elem->peer_id_hash = other_hash;
356 s_elem->num_change++;
358 else if (0 > GNUNET_CRYPTO_hash_cmp (&other_hash, &s_elem->peer_id_hash))
360 LOG (GNUNET_ERROR_TYPE_DEBUG, " Got PeerID %s\n",
362 LOG (GNUNET_ERROR_TYPE_DEBUG, "Discarding old PeerID %s\n",
363 GNUNET_i2s (&s_elem->peer_id));
365 s_elem->num_change++;
369 LOG (GNUNET_ERROR_TYPE_DEBUG, " Got PeerID %s\n",
371 LOG (GNUNET_ERROR_TYPE_DEBUG, "Keeping old PeerID %s\n",
372 GNUNET_i2s (&s_elem->peer_id));
375 s_elem->is_empty = NOT_EMPTY;
380 * Get the size of the sampler.
382 * @param sampler the sampler to return the size of.
383 * @return the size of the sampler
386 RPS_sampler_get_size (struct RPS_Sampler *sampler)
388 return sampler->sampler_size;
393 * Grow or shrink the size of the sampler.
395 * @param sampler the sampler to resize.
396 * @param new_size the new size of the sampler
399 sampler_resize (struct RPS_Sampler *sampler, unsigned int new_size)
401 unsigned int old_size;
404 // TODO check min and max size
406 old_size = sampler->sampler_size;
408 if (old_size > new_size)
410 /* Temporary store those to properly call the removeCB on those later */
412 LOG (GNUNET_ERROR_TYPE_DEBUG, "Shrinking sampler %d -> %d\n", old_size, new_size);
413 GNUNET_array_grow (sampler->sampler_elements, sampler->sampler_size, new_size);
414 LOG (GNUNET_ERROR_TYPE_DEBUG,
415 "sampler->sampler_elements now points to %p\n",
416 sampler->sampler_elements);
419 else if (old_size < new_size)
421 LOG (GNUNET_ERROR_TYPE_DEBUG, "Growing sampler %d -> %d\n", old_size, new_size);
422 GNUNET_array_grow (sampler->sampler_elements, sampler->sampler_size, new_size);
423 LOG (GNUNET_ERROR_TYPE_DEBUG,
424 "sampler->sampler_elements now points to %p\n",
425 sampler->sampler_elements);
427 for ( i = old_size ; i < new_size ; i++ )
428 { /* Add new sampler elements */
429 sampler->sampler_elements[i] = RPS_sampler_elem_create ();
430 LOG (GNUNET_ERROR_TYPE_DEBUG,
431 "Added %" PRIX32 ". sampler, now pointing to %p, contains %s\n",
432 i, &sampler->sampler_elements[i], GNUNET_i2s (&sampler->sampler_elements[i]->peer_id));
437 LOG (GNUNET_ERROR_TYPE_DEBUG, "Size remains the same -- nothing to do\n");
441 GNUNET_assert (sampler->sampler_size == new_size);
442 LOG (GNUNET_ERROR_TYPE_DEBUG, "Finished growing/shrinking.\n"); // remove
447 * Grow or shrink the size of the sampler.
449 * @param sampler the sampler to resize.
450 * @param new_size the new size of the sampler
453 RPS_sampler_resize (struct RPS_Sampler *sampler, unsigned int new_size)
455 GNUNET_assert (0 < new_size);
456 sampler_resize (sampler, new_size);
463 * @param sampler the sampler to empty.
464 * @param new_size the new size of the sampler
467 sampler_empty (struct RPS_Sampler *sampler)
469 sampler_resize (sampler, 0);
474 * Initialise a tuple of sampler elements.
476 * @param init_size the size the sampler is initialised with
477 * @param ins_cb the callback that will be called on every PeerID that is
478 * newly inserted into a sampler element
479 * @param ins_cls the closure given to #ins_cb
480 * @param rem_cb the callback that will be called on every PeerID that is
481 * removed from a sampler element
482 * @param rem_cls the closure given to #rem_cb
483 * @return a handle to a sampler that consists of sampler elements.
486 RPS_sampler_init (size_t init_size,
487 struct GNUNET_TIME_Relative max_round_interval)
489 struct RPS_Sampler *sampler;
492 /* Initialise context around extended sampler */
493 min_size = 10; // TODO make input to _samplers_init()
494 max_size = 1000; // TODO make input to _samplers_init()
496 sampler = GNUNET_new (struct RPS_Sampler);
497 sampler->sampler_size = 0;
498 sampler->sampler_elements = NULL;
499 sampler->max_round_interval = max_round_interval;
500 //sampler->sampler_elements = GNUNET_new_array(init_size, struct GNUNET_PeerIdentity);
501 //GNUNET_array_grow (sampler->sampler_elements, sampler->sampler_size, min_size);
502 RPS_sampler_resize (sampler, init_size);
504 client_get_index = 0;
506 //GNUNET_assert (init_size == sampler->sampler_size);
512 * A fuction to update every sampler in the given list
514 * @param sampler the sampler to update.
515 * @param id the PeerID that is put in the sampler
518 RPS_sampler_update (struct RPS_Sampler *sampler,
519 const struct GNUNET_PeerIdentity *id)
523 for ( i = 0 ; i < sampler->sampler_size ; i++ )
524 RPS_sampler_elem_next (sampler->sampler_elements[i],
531 * Reinitialise all previously initialised sampler elements with the given value.
533 * Used to get rid of a PeerID.
535 * @param sampler the sampler to reinitialise a sampler element in.
536 * @param id the id of the sampler elements to update.
539 RPS_sampler_reinitialise_by_value (struct RPS_Sampler *sampler,
540 const struct GNUNET_PeerIdentity *id)
544 for ( i = 0 ; i < sampler->sampler_size ; i++ )
546 if ( 0 == GNUNET_CRYPTO_cmp_peer_identity(id, &(sampler->sampler_elements[i]->peer_id)) )
548 LOG (GNUNET_ERROR_TYPE_DEBUG, "Reinitialising sampler\n");
549 RPS_sampler_elem_reinit (sampler->sampler_elements[i]);
556 * Get one random peer out of the sampled peers.
558 * We might want to reinitialise this sampler after giving the
559 * corrsponding peer to the client.
560 * Only used internally
563 sampler_get_rand_peer2 (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
565 struct GetPeerCls *gpc = (struct GetPeerCls *) cls;
568 gpc->get_peer_task = NULL;
569 GNUNET_CONTAINER_DLL_remove (gpc_head, gpc_tail, gpc);
570 if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
574 * Choose the r_index of the peer we want to return
575 * at random from the interval of the gossip list
577 r_index = GNUNET_CRYPTO_random_u64 (GNUNET_CRYPTO_QUALITY_STRONG,
578 gpc->sampler->sampler_size);
580 if ( EMPTY == gpc->sampler->sampler_elements[r_index]->is_empty )
582 gpc->get_peer_task = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_relative_multiply(
583 GNUNET_TIME_UNIT_SECONDS,
585 &sampler_get_rand_peer2,
590 *gpc->id = gpc->sampler->sampler_elements[r_index]->peer_id;
592 gpc->cont (gpc->cont_cls, gpc->id);
598 * Get one random peer out of the sampled peers.
600 * We might want to reinitialise this sampler after giving the
601 * corrsponding peer to the client.
604 sampler_get_rand_peer (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
606 struct GetPeerCls *gpc = (struct GetPeerCls *) cls;
607 struct GNUNET_PeerIdentity tmp_id;
608 unsigned int empty_flag;
609 struct RPS_SamplerElement *s_elem;
610 struct GNUNET_TIME_Relative last_request_diff;
611 uint32_t tmp_client_get_index;
613 gpc->get_peer_task = NULL;
614 if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
617 LOG (GNUNET_ERROR_TYPE_DEBUG, "Single peer was requested\n");
620 /* Store the next #client_get_index to check whether we cycled over the whole list */
621 if (0 < client_get_index)
622 tmp_client_get_index = client_get_index - 1;
624 tmp_client_get_index = gpc->sampler->sampler_size - 1;
626 LOG (GNUNET_ERROR_TYPE_DEBUG,
627 "sched for later if index reaches %" PRIX32 " (sampler size: %" PRIX32 ").\n",
628 tmp_client_get_index, gpc->sampler->sampler_size);
631 { /* Get first non empty sampler */
632 if (tmp_client_get_index == client_get_index)
633 { /* We once cycled over the whole list */
634 LOG (GNUNET_ERROR_TYPE_DEBUG, "reached tmp_index %" PRIX32 ".\n",
636 GNUNET_assert (NULL == gpc->get_peer_task);
638 GNUNET_SCHEDULER_add_delayed (gpc->sampler->max_round_interval,
639 &sampler_get_rand_peer,
644 tmp_id = gpc->sampler->sampler_elements[client_get_index]->peer_id;
645 empty_flag = gpc->sampler->sampler_elements[client_get_index]->is_empty;
646 RPS_sampler_elem_reinit (gpc->sampler->sampler_elements[client_get_index]);
647 if (EMPTY != empty_flag)
648 RPS_sampler_elem_next (gpc->sampler->sampler_elements[client_get_index],
652 /* Cycle the #client_get_index one step further */
653 if ( client_get_index == gpc->sampler->sampler_size - 1 )
654 client_get_index = 0;
658 LOG (GNUNET_ERROR_TYPE_DEBUG, "incremented index to %" PRIX32 ".\n",
660 } while (EMPTY == gpc->sampler->sampler_elements[client_get_index]->is_empty);
662 s_elem = gpc->sampler->sampler_elements[client_get_index];
663 *gpc->id = s_elem->peer_id;
665 /* Check whether we may use this sampler to give it back to the client */
666 if (GNUNET_TIME_UNIT_FOREVER_ABS.abs_value_us != s_elem->last_client_request.abs_value_us)
669 GNUNET_TIME_absolute_get_difference (s_elem->last_client_request,
670 GNUNET_TIME_absolute_get ());
671 /* We're not going to give it back now if it was
672 * already requested by a client this round */
673 if (last_request_diff.rel_value_us < gpc->sampler->max_round_interval.rel_value_us)
675 LOG (GNUNET_ERROR_TYPE_DEBUG,
676 "Last client request on this sampler was less than max round interval ago -- scheduling for later\n");
677 ///* How many time remains untile the next round has started? */
678 //inv_last_request_diff =
679 // GNUNET_TIME_absolute_get_difference (last_request_diff,
680 // sampler->max_round_interval);
681 // add a little delay
682 /* Schedule it one round later */
683 GNUNET_assert (NULL == gpc->get_peer_task);
685 GNUNET_SCHEDULER_add_delayed (gpc->sampler->max_round_interval,
686 &sampler_get_rand_peer,
690 // TODO add other reasons to wait here
693 s_elem->last_client_request = GNUNET_TIME_absolute_get ();
695 GNUNET_CONTAINER_DLL_remove (gpc_head, gpc_tail, gpc);
696 gpc->cont (gpc->cont_cls, gpc->id);
702 * Get n random peers out of the sampled peers.
704 * We might want to reinitialise this sampler after giving the
705 * corrsponding peer to the client.
706 * Random with or without consumption?
708 * @param sampler the sampler to get peers from.
709 * @param cb callback that will be called once the ids are ready.
710 * @param cls closure given to @a cb
711 * @param for_client #GNUNET_YES if result is used for client,
712 * #GNUNET_NO if used internally
713 * @param num_peers the number of peers requested
716 RPS_sampler_get_n_rand_peers (struct RPS_Sampler *sampler,
717 RPS_sampler_n_rand_peers_ready_cb cb,
718 void *cls, uint32_t num_peers, int for_client)
720 GNUNET_assert (0 != sampler->sampler_size);
722 // TODO check if we have too much (distinct) sampled peers
724 struct NRandPeersReadyCls *cb_cls;
725 struct GetPeerCls *gpc;
727 cb_cls = GNUNET_new (struct NRandPeersReadyCls);
728 cb_cls->num_peers = num_peers;
729 cb_cls->cur_num_peers = 0;
730 cb_cls->ids = GNUNET_new_array (num_peers, struct GNUNET_PeerIdentity);
731 cb_cls->callback = cb;
734 LOG (GNUNET_ERROR_TYPE_DEBUG,
735 "Scheduling requests for %" PRIX32 " peers\n", num_peers);
737 for ( i = 0 ; i < num_peers ; i++ )
739 gpc = GNUNET_new (struct GetPeerCls);
740 gpc->sampler = sampler;
741 gpc->cont = check_n_peers_ready;
742 gpc->cont_cls = cb_cls;
743 gpc->id = &cb_cls->ids[i];
745 // maybe add a little delay
746 if (GNUNET_YES == for_client)
747 gpc->get_peer_task = GNUNET_SCHEDULER_add_now (&sampler_get_rand_peer, gpc);
748 else if (GNUNET_NO == for_client)
749 gpc->get_peer_task = GNUNET_SCHEDULER_add_now (&sampler_get_rand_peer2, gpc);
753 GNUNET_CONTAINER_DLL_insert (gpc_head, gpc_tail, gpc);
759 * Counts how many Samplers currently hold a given PeerID.
761 * @param sampler the sampler to count ids in.
762 * @param id the PeerID to count.
764 * @return the number of occurrences of id.
767 RPS_sampler_count_id (struct RPS_Sampler *sampler,
768 const struct GNUNET_PeerIdentity *id)
774 for ( i = 0 ; i < sampler->sampler_size ; i++ )
776 if ( 0 == GNUNET_CRYPTO_cmp_peer_identity (&sampler->sampler_elements[i]->peer_id, id)
777 && EMPTY != sampler->sampler_elements[i]->is_empty)
785 * Cleans the sampler.
788 RPS_sampler_destroy (struct RPS_Sampler *sampler)
790 struct GetPeerCls *i;
792 for (i = gpc_head; NULL != i; i = gpc_head)
794 GNUNET_CONTAINER_DLL_remove (gpc_head, gpc_tail, i);
795 GNUNET_SCHEDULER_cancel (i->get_peer_task);
799 sampler_empty (sampler);
800 GNUNET_free (sampler);
803 /* end of gnunet-service-rps.c */