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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 for #sampler_get_rand_peer()
181 struct GetPeerCls *next;
186 struct GetPeerCls *prev;
189 * The sampler this function operates on.
191 struct RPS_Sampler *sampler;
194 * The task for this function.
196 struct GNUNET_SCHEDULER_Task *get_peer_task;
201 RPS_sampler_rand_peer_ready_cont cont;
204 * The closure to the callback @e cont
209 * The address of the id to be stored at
211 struct GNUNET_PeerIdentity *id;
216 // * Global sampler variable.
218 //struct RPS_Sampler *sampler;
222 * The minimal size for the extended sampler elements.
224 static size_t min_size;
227 * The maximal size the extended sampler elements should grow to.
229 static size_t max_size;
232 * The size the extended sampler elements currently have.
234 //static size_t extra_size;
237 * Inedex to the sampler element that is the next to be returned
239 static uint32_t client_get_index;
242 /** FIXME document */
243 static struct GetPeerCls *gpc_head;
244 static struct GetPeerCls *gpc_tail;
248 * Callback to _get_rand_peer() used by _get_n_rand_peers().
250 * Checks whether all n peers are available. If they are,
254 check_n_peers_ready (void *cls,
255 const struct GNUNET_PeerIdentity *id)
257 struct NRandPeersReadyCls *n_peers_cls = cls;
259 n_peers_cls->cur_num_peers++;
260 LOG (GNUNET_ERROR_TYPE_DEBUG,
261 "Got %" PRIX32 ". of %" PRIX32 " peers\n",
262 n_peers_cls->cur_num_peers, n_peers_cls->num_peers);
264 if (n_peers_cls->num_peers == n_peers_cls->cur_num_peers)
265 { /* All peers are ready -- return those to the client */
266 GNUNET_assert (NULL != n_peers_cls->callback);
268 LOG (GNUNET_ERROR_TYPE_DEBUG,
269 "returning %" PRIX32 " peers to the client\n",
270 n_peers_cls->num_peers);
271 n_peers_cls->callback (n_peers_cls->cls, n_peers_cls->ids, n_peers_cls->num_peers);
273 GNUNET_free (n_peers_cls);
279 * Reinitialise a previously initialised sampler element.
281 * @param sampler pointer to the memory that keeps the value.
284 RPS_sampler_elem_reinit (struct RPS_SamplerElement *sampler_el)
286 sampler_el->is_empty = EMPTY;
288 // I guess I don't need to call GNUNET_CRYPTO_hmac_derive_key()...
289 GNUNET_CRYPTO_random_block(GNUNET_CRYPTO_QUALITY_STRONG,
290 &(sampler_el->auth_key.key),
291 GNUNET_CRYPTO_HASH_LENGTH);
293 sampler_el->last_client_request = GNUNET_TIME_UNIT_FOREVER_ABS;
295 sampler_el->birth = GNUNET_TIME_absolute_get ();
296 sampler_el->num_peers = 0;
297 sampler_el->num_change = 0;
302 * (Re)Initialise given Sampler with random min-wise independent function.
304 * In this implementation this means choosing an auth_key for later use in
307 * @return a newly created RPS_SamplerElement which currently holds no id.
309 struct RPS_SamplerElement *
310 RPS_sampler_elem_create (void)
312 struct RPS_SamplerElement *s;
314 s = GNUNET_new (struct RPS_SamplerElement);
316 RPS_sampler_elem_reinit (s);
317 LOG (GNUNET_ERROR_TYPE_DEBUG, "initialised with empty PeerID\n");
324 * Input an PeerID into the given sampler element.
326 * @param sampler the sampler the @a s_elem belongs to.
330 RPS_sampler_elem_next (struct RPS_SamplerElement *s_elem,
331 struct RPS_Sampler *sampler,
332 const struct GNUNET_PeerIdentity *other)
334 struct GNUNET_HashCode other_hash;
338 if (0 == GNUNET_CRYPTO_cmp_peer_identity (other, &(s_elem->peer_id)))
340 LOG (GNUNET_ERROR_TYPE_DEBUG, " Got PeerID %s\n",
342 LOG (GNUNET_ERROR_TYPE_DEBUG, "Have already PeerID %s\n",
343 GNUNET_i2s (&(s_elem->peer_id)));
347 GNUNET_CRYPTO_hmac(&s_elem->auth_key,
349 sizeof(struct GNUNET_PeerIdentity),
352 if (EMPTY == s_elem->is_empty)
354 LOG (GNUNET_ERROR_TYPE_DEBUG,
355 "Got PeerID %s; Simply accepting (was empty previously).\n",
357 s_elem->peer_id = *other;
358 s_elem->peer_id_hash = other_hash;
360 s_elem->num_change++;
362 else if (0 > GNUNET_CRYPTO_hash_cmp (&other_hash, &s_elem->peer_id_hash))
364 LOG (GNUNET_ERROR_TYPE_DEBUG, " Got PeerID %s\n",
366 LOG (GNUNET_ERROR_TYPE_DEBUG, "Discarding old PeerID %s\n",
367 GNUNET_i2s (&s_elem->peer_id));
369 s_elem->num_change++;
373 LOG (GNUNET_ERROR_TYPE_DEBUG, " Got PeerID %s\n",
375 LOG (GNUNET_ERROR_TYPE_DEBUG, "Keeping old PeerID %s\n",
376 GNUNET_i2s (&s_elem->peer_id));
379 s_elem->is_empty = NOT_EMPTY;
384 * Get the size of the sampler.
386 * @param sampler the sampler to return the size of.
387 * @return the size of the sampler
390 RPS_sampler_get_size (struct RPS_Sampler *sampler)
392 return sampler->sampler_size;
397 * Grow or shrink the size of the sampler.
399 * @param sampler the sampler to resize.
400 * @param new_size the new size of the sampler
403 sampler_resize (struct RPS_Sampler *sampler, unsigned int new_size)
405 unsigned int old_size;
408 // TODO check min and max size
410 old_size = sampler->sampler_size;
412 if (old_size > new_size)
414 /* Temporary store those to properly call the removeCB on those later */
416 LOG (GNUNET_ERROR_TYPE_DEBUG, "Shrinking sampler %d -> %d\n", old_size, new_size);
417 GNUNET_array_grow (sampler->sampler_elements, sampler->sampler_size, new_size);
418 LOG (GNUNET_ERROR_TYPE_DEBUG,
419 "sampler->sampler_elements now points to %p\n",
420 sampler->sampler_elements);
423 else if (old_size < new_size)
425 LOG (GNUNET_ERROR_TYPE_DEBUG, "Growing sampler %d -> %d\n", old_size, new_size);
426 GNUNET_array_grow (sampler->sampler_elements, sampler->sampler_size, new_size);
427 LOG (GNUNET_ERROR_TYPE_DEBUG,
428 "sampler->sampler_elements now points to %p\n",
429 sampler->sampler_elements);
431 for ( i = old_size ; i < new_size ; i++ )
432 { /* Add new sampler elements */
433 sampler->sampler_elements[i] = RPS_sampler_elem_create ();
434 LOG (GNUNET_ERROR_TYPE_DEBUG,
435 "Added %" PRIX32 ". sampler, now pointing to %p, contains %s\n",
436 i, &sampler->sampler_elements[i], GNUNET_i2s (&sampler->sampler_elements[i]->peer_id));
441 LOG (GNUNET_ERROR_TYPE_DEBUG, "Size remains the same -- nothing to do\n");
445 GNUNET_assert (sampler->sampler_size == new_size);
446 LOG (GNUNET_ERROR_TYPE_DEBUG, "Finished growing/shrinking.\n"); // remove
451 * Grow or shrink the size of the sampler.
453 * @param sampler the sampler to resize.
454 * @param new_size the new size of the sampler
457 RPS_sampler_resize (struct RPS_Sampler *sampler, unsigned int new_size)
459 GNUNET_assert (0 < new_size);
460 sampler_resize (sampler, new_size);
467 * @param sampler the sampler to empty.
468 * @param new_size the new size of the sampler
471 sampler_empty (struct RPS_Sampler *sampler)
473 sampler_resize (sampler, 0);
478 * Initialise a tuple of sampler elements.
480 * @param init_size the size the sampler is initialised with
481 * @param ins_cb the callback that will be called on every PeerID that is
482 * newly inserted into a sampler element
483 * @param ins_cls the closure given to #ins_cb
484 * @param rem_cb the callback that will be called on every PeerID that is
485 * removed from a sampler element
486 * @param rem_cls the closure given to #rem_cb
487 * @return a handle to a sampler that consists of sampler elements.
490 RPS_sampler_init (size_t init_size,
491 struct GNUNET_TIME_Relative max_round_interval)
493 struct RPS_Sampler *sampler;
496 /* Initialise context around extended sampler */
497 min_size = 10; // TODO make input to _samplers_init()
498 max_size = 1000; // TODO make input to _samplers_init()
500 sampler = GNUNET_new (struct RPS_Sampler);
501 sampler->sampler_size = 0;
502 sampler->sampler_elements = NULL;
503 sampler->max_round_interval = max_round_interval;
504 //sampler->sampler_elements = GNUNET_new_array(init_size, struct GNUNET_PeerIdentity);
505 //GNUNET_array_grow (sampler->sampler_elements, sampler->sampler_size, min_size);
506 RPS_sampler_resize (sampler, init_size);
508 client_get_index = 0;
510 //GNUNET_assert (init_size == sampler->sampler_size);
516 * A fuction to update every sampler in the given list
518 * @param sampler the sampler to update.
519 * @param id the PeerID that is put in the sampler
522 RPS_sampler_update (struct RPS_Sampler *sampler,
523 const struct GNUNET_PeerIdentity *id)
527 for ( i = 0 ; i < sampler->sampler_size ; i++ )
528 RPS_sampler_elem_next (sampler->sampler_elements[i],
535 * Reinitialise all previously initialised sampler elements with the given value.
537 * Used to get rid of a PeerID.
539 * @param sampler the sampler to reinitialise a sampler element in.
540 * @param id the id of the sampler elements to update.
543 RPS_sampler_reinitialise_by_value (struct RPS_Sampler *sampler,
544 const struct GNUNET_PeerIdentity *id)
548 for ( i = 0 ; i < sampler->sampler_size ; i++ )
550 if ( 0 == GNUNET_CRYPTO_cmp_peer_identity(id, &(sampler->sampler_elements[i]->peer_id)) )
552 LOG (GNUNET_ERROR_TYPE_DEBUG, "Reinitialising sampler\n");
553 RPS_sampler_elem_reinit (sampler->sampler_elements[i]);
560 * Get one random peer out of the sampled peers.
562 * We might want to reinitialise this sampler after giving the
563 * corrsponding peer to the client.
564 * Only used internally
567 sampler_get_rand_peer2 (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
569 struct GetPeerCls *gpc = cls;
572 gpc->get_peer_task = NULL;
573 GNUNET_CONTAINER_DLL_remove (gpc_head, gpc_tail, gpc);
574 if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
578 * Choose the r_index of the peer we want to return
579 * at random from the interval of the gossip list
581 r_index = GNUNET_CRYPTO_random_u64 (GNUNET_CRYPTO_QUALITY_STRONG,
582 gpc->sampler->sampler_size);
584 if ( EMPTY == gpc->sampler->sampler_elements[r_index]->is_empty )
586 gpc->get_peer_task = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_relative_multiply(
587 GNUNET_TIME_UNIT_SECONDS,
589 &sampler_get_rand_peer2,
594 *gpc->id = gpc->sampler->sampler_elements[r_index]->peer_id;
596 gpc->cont (gpc->cont_cls, gpc->id);
602 * Get one random peer out of the sampled peers.
604 * We might want to reinitialise this sampler after giving the
605 * corrsponding peer to the client.
608 sampler_get_rand_peer (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
610 struct GetPeerCls *gpc = cls;
611 struct GNUNET_PeerIdentity tmp_id;
612 unsigned int empty_flag;
613 struct RPS_SamplerElement *s_elem;
614 struct GNUNET_TIME_Relative last_request_diff;
615 uint32_t tmp_client_get_index;
617 gpc->get_peer_task = NULL;
618 if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
621 LOG (GNUNET_ERROR_TYPE_DEBUG, "Single peer was requested\n");
624 /* Store the next #client_get_index to check whether we cycled over the whole list */
625 if (0 < client_get_index)
626 tmp_client_get_index = client_get_index - 1;
628 tmp_client_get_index = gpc->sampler->sampler_size - 1;
630 LOG (GNUNET_ERROR_TYPE_DEBUG,
631 "sched for later if index reaches %" PRIX32 " (sampler size: %" PRIX32 ").\n",
632 tmp_client_get_index, gpc->sampler->sampler_size);
635 { /* Get first non empty sampler */
636 if (tmp_client_get_index == client_get_index)
637 { /* We once cycled over the whole list */
638 LOG (GNUNET_ERROR_TYPE_DEBUG, "reached tmp_index %" PRIX32 ".\n",
640 GNUNET_assert (NULL == gpc->get_peer_task);
642 GNUNET_SCHEDULER_add_delayed (gpc->sampler->max_round_interval,
643 &sampler_get_rand_peer,
648 tmp_id = gpc->sampler->sampler_elements[client_get_index]->peer_id;
649 empty_flag = gpc->sampler->sampler_elements[client_get_index]->is_empty;
650 RPS_sampler_elem_reinit (gpc->sampler->sampler_elements[client_get_index]);
651 if (EMPTY != empty_flag)
652 RPS_sampler_elem_next (gpc->sampler->sampler_elements[client_get_index],
656 /* Cycle the #client_get_index one step further */
657 if ( client_get_index == gpc->sampler->sampler_size - 1 )
658 client_get_index = 0;
662 LOG (GNUNET_ERROR_TYPE_DEBUG, "incremented index to %" PRIX32 ".\n",
664 } while (EMPTY == gpc->sampler->sampler_elements[client_get_index]->is_empty);
666 s_elem = gpc->sampler->sampler_elements[client_get_index];
667 *gpc->id = s_elem->peer_id;
669 /* Check whether we may use this sampler to give it back to the client */
670 if (GNUNET_TIME_UNIT_FOREVER_ABS.abs_value_us != s_elem->last_client_request.abs_value_us)
673 GNUNET_TIME_absolute_get_difference (s_elem->last_client_request,
674 GNUNET_TIME_absolute_get ());
675 /* We're not going to give it back now if it was
676 * already requested by a client this round */
677 if (last_request_diff.rel_value_us < gpc->sampler->max_round_interval.rel_value_us)
679 LOG (GNUNET_ERROR_TYPE_DEBUG,
680 "Last client request on this sampler was less than max round interval ago -- scheduling for later\n");
681 ///* How many time remains untile the next round has started? */
682 //inv_last_request_diff =
683 // GNUNET_TIME_absolute_get_difference (last_request_diff,
684 // sampler->max_round_interval);
685 // add a little delay
686 /* Schedule it one round later */
687 GNUNET_assert (NULL == gpc->get_peer_task);
689 GNUNET_SCHEDULER_add_delayed (gpc->sampler->max_round_interval,
690 &sampler_get_rand_peer,
694 // TODO add other reasons to wait here
697 s_elem->last_client_request = GNUNET_TIME_absolute_get ();
699 GNUNET_CONTAINER_DLL_remove (gpc_head, gpc_tail, gpc);
700 gpc->cont (gpc->cont_cls, gpc->id);
706 * Get n random peers out of the sampled peers.
708 * We might want to reinitialise this sampler after giving the
709 * corrsponding peer to the client.
710 * Random with or without consumption?
712 * @param sampler the sampler to get peers from.
713 * @param cb callback that will be called once the ids are ready.
714 * @param cls closure given to @a cb
715 * @param for_client #GNUNET_YES if result is used for client,
716 * #GNUNET_NO if used internally
717 * @param num_peers the number of peers requested
720 RPS_sampler_get_n_rand_peers (struct RPS_Sampler *sampler,
721 RPS_sampler_n_rand_peers_ready_cb cb,
722 void *cls, uint32_t num_peers, int for_client)
724 GNUNET_assert (0 != sampler->sampler_size);
726 // TODO check if we have too much (distinct) sampled peers
728 struct NRandPeersReadyCls *cb_cls;
729 struct GetPeerCls *gpc;
731 cb_cls = GNUNET_new (struct NRandPeersReadyCls);
732 cb_cls->num_peers = num_peers;
733 cb_cls->cur_num_peers = 0;
734 cb_cls->ids = GNUNET_new_array (num_peers, struct GNUNET_PeerIdentity);
735 cb_cls->callback = cb;
738 LOG (GNUNET_ERROR_TYPE_DEBUG,
739 "Scheduling requests for %" PRIX32 " peers\n", num_peers);
741 for ( i = 0 ; i < num_peers ; i++ )
743 gpc = GNUNET_new (struct GetPeerCls);
744 gpc->sampler = sampler;
745 gpc->cont = check_n_peers_ready;
746 gpc->cont_cls = cb_cls;
747 gpc->id = &cb_cls->ids[i];
749 // maybe add a little delay
750 if (GNUNET_YES == for_client)
751 gpc->get_peer_task = GNUNET_SCHEDULER_add_now (&sampler_get_rand_peer, gpc);
752 else if (GNUNET_NO == for_client)
753 gpc->get_peer_task = GNUNET_SCHEDULER_add_now (&sampler_get_rand_peer2, gpc);
757 GNUNET_CONTAINER_DLL_insert (gpc_head, gpc_tail, gpc);
763 * Counts how many Samplers currently hold a given PeerID.
765 * @param sampler the sampler to count ids in.
766 * @param id the PeerID to count.
768 * @return the number of occurrences of id.
771 RPS_sampler_count_id (struct RPS_Sampler *sampler,
772 const struct GNUNET_PeerIdentity *id)
778 for ( i = 0 ; i < sampler->sampler_size ; i++ )
780 if ( 0 == GNUNET_CRYPTO_cmp_peer_identity (&sampler->sampler_elements[i]->peer_id, id)
781 && EMPTY != sampler->sampler_elements[i]->is_empty)
789 * Cleans the sampler.
792 RPS_sampler_destroy (struct RPS_Sampler *sampler)
794 struct GetPeerCls *i;
796 for (i = gpc_head; NULL != i; i = gpc_head)
798 GNUNET_CONTAINER_DLL_remove (gpc_head, gpc_tail, i);
799 GNUNET_SCHEDULER_cancel (i->get_peer_task);
803 sampler_empty (sampler);
804 GNUNET_free (sampler);
807 /* end of gnunet-service-rps.c */