2 This file is part of GNUnet.
3 (C) 2011 Christian Grothoff (and other contributing authors)
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22 * @file fs/gnunet-service-fs_pe.c
23 * @brief API to manage query plan
24 * @author Christian Grothoff
27 #include "gnunet-service-fs.h"
28 #include "gnunet-service-fs_cp.h"
29 #include "gnunet-service-fs_pe.h"
30 #include "gnunet-service-fs_pr.h"
34 * List of GSF_PendingRequests this request plan
37 struct PendingRequestList;
40 * Transmission plan for a peer.
46 * DLL of request plans a particular pending request is
49 struct GSF_RequestPlanReference
53 * This is a doubly-linked list.
55 struct GSF_RequestPlanReference *next;
58 * This is a doubly-linked list.
60 struct GSF_RequestPlanReference *prev;
63 * Associated request plan.
65 struct GSF_RequestPlan *rp;
68 * Corresponding PendingRequestList.
70 struct PendingRequestList *prl;
75 * List of GSF_PendingRequests this request plan
78 struct PendingRequestList
82 * This is a doubly-linked list.
84 struct PendingRequestList *next;
87 * This is a doubly-linked list.
89 struct PendingRequestList *prev;
92 * Associated pending request.
94 struct GSF_PendingRequest *pr;
97 * Corresponding GSF_RequestPlanReference.
99 struct GSF_RequestPlanReference *rpr;
105 * Information we keep per request per peer. This is a doubly-linked
106 * list (with head and tail in the 'struct GSF_PendingRequestData')
107 * with one entry in each heap of each 'struct PeerPlan'. Each
108 * entry tracks information relevant for this request and this peer.
110 struct GSF_RequestPlan
114 * This is a doubly-linked list.
116 struct GSF_RequestPlan *next;
119 * This is a doubly-linked list.
121 struct GSF_RequestPlan *prev;
124 * Heap node associated with this request and this peer.
126 struct GNUNET_CONTAINER_HeapNode *hn;
129 * The transmission plan for a peer that this request is associated with.
134 * Head of list of associated pending requests.
136 struct PendingRequestList *prl_head;
139 * Tail of list of associated pending requests.
141 struct PendingRequestList *prl_tail;
144 * Earliest time we'd be happy to (re)transmit this request.
146 struct GNUNET_TIME_Absolute earliest_transmission;
149 * When was the last time we transmitted this request to this peer? 0 for never.
151 struct GNUNET_TIME_Absolute last_transmission;
154 * Current priority for this request for this target.
159 * How often did we transmit this request to this peer?
161 unsigned int transmission_counter;
167 * Transmission plan for a peer.
172 * Heap with pending queries (struct GSF_RequestPlan), higher weights mean higher priority.
174 struct GNUNET_CONTAINER_Heap *priority_heap;
177 * Heap with pending queries (struct GSF_RequestPlan), by transmission time, lowest first.
179 struct GNUNET_CONTAINER_Heap *delay_heap;
182 * Map of queries to plan entries. All entries in the priority_heap or delay_heap
183 * should be in the plan map. Note that it IS possible for the plan map to have
184 * multiple entries for the same query.
186 struct GNUNET_CONTAINER_MultiHashMap *plan_map;
189 * Current transmission request handle.
191 struct GSF_PeerTransmitHandle *pth;
194 * Peer for which this is the plan.
196 struct GSF_ConnectedPeer *cp;
199 * Current task for executing the plan.
201 GNUNET_SCHEDULER_TaskIdentifier task;
206 * Hash map from peer identities to PeerPlans.
208 static struct GNUNET_CONTAINER_MultiHashMap *plans;
211 * Sum of all transmission counters (equals total delay for all plan entries).
213 static unsigned long long total_delay;
216 * Number of plan entries.
218 static unsigned long long plan_count;
222 * Return the query (key in the plan_map) for the given request plan.
224 * @param rp a request plan
225 * @return the associated query
227 static const GNUNET_HashCode *
228 get_rp_key (struct GSF_RequestPlan *rp)
230 return &GSF_pending_request_get_data_ (rp->prl_head->pr)->query;
235 * Figure out when and how to transmit to the given peer.
237 * @param cls the 'struct GSF_ConnectedPeer' for transmission
238 * @param tc scheduler context
241 schedule_peer_transmission (void *cls,
242 const struct GNUNET_SCHEDULER_TaskContext *tc);
246 * Insert the given request plan into the heap with the appropriate weight.
248 * @param pp associated peer's plan
249 * @param rp request to plan
252 plan (struct PeerPlan *pp, struct GSF_RequestPlan *rp)
254 #define N ((double)128.0)
256 * Running average delay we currently impose.
258 static double avg_delay;
260 struct GSF_PendingRequestData *prd;
261 struct GNUNET_TIME_Relative delay;
263 GNUNET_assert (rp->pp == pp);
264 GNUNET_STATISTICS_set (GSF_stats,
265 gettext_noop ("# average retransmission delay (ms)"),
266 total_delay * 1000LL / plan_count, GNUNET_NO);
267 prd = GSF_pending_request_get_data_ (rp->prl_head->pr);
269 if (rp->transmission_counter < 8)
271 GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS,
272 rp->transmission_counter);
273 else if (rp->transmission_counter < 32)
275 GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS,
277 (1LL << (rp->transmission_counter - 8)));
280 GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS,
283 GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK,
284 delay.rel_value + 1);
285 /* Add 0.01 to avg_delay to avoid division-by-zero later */
286 avg_delay = (((avg_delay * (N-1.0)) + delay.rel_value) / N) + 0.01;
289 For the priority, we need to consider a few basic rules:
290 1) if we just started requesting (delay is small), we should
291 virtually always have a priority of zero.
292 2) for requests with average latency, our priority should match
293 the average priority observed on the network
294 3) even the longest-running requests should not be WAY out of
295 the observed average (thus we bound by a factor of 2)
296 4) we add +1 to the observed average priority to avoid everyone
297 staying put at zero (2 * 0 = 0...).
299 Using the specific calculation below, we get:
301 delay = 0 => priority = 0;
302 delay = avg delay => priority = running-average-observed-priority;
303 delay >> avg_delay => priority = 2 * running-average-observed-priority;
305 which satisfies all of the rules above.
307 Note: M_PI_4 = PI/4 = arctan(1)
309 rp->priority = round ((GSF_current_priorities + 1.0) * atan (delay.rel_value / avg_delay)) / M_PI_4;
310 /* Note: usage of 'round' and 'atan' requires -lm */
312 if (rp->transmission_counter != 0)
313 delay.rel_value += TTL_DECREMENT;
314 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
315 "Considering (re)transmission number %u in %llu ms\n",
316 (unsigned int) rp->transmission_counter,
317 (unsigned long long) delay.rel_value);
318 rp->earliest_transmission = GNUNET_TIME_relative_to_absolute (delay);
320 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
321 "Earliest (re)transmission for `%s' in %us\n",
322 GNUNET_h2s (&prd->query), rp->transmission_counter);
325 GNUNET_assert (rp->hn == NULL);
326 if (GNUNET_TIME_absolute_get_remaining (rp->earliest_transmission).rel_value
328 rp->hn = GNUNET_CONTAINER_heap_insert (pp->priority_heap, rp, rp->priority);
331 GNUNET_CONTAINER_heap_insert (pp->delay_heap, rp,
332 rp->earliest_transmission.abs_value);
333 GNUNET_assert (GNUNET_YES ==
334 GNUNET_CONTAINER_multihashmap_contains_value (pp->plan_map,
337 if (GNUNET_SCHEDULER_NO_TASK != pp->task)
338 GNUNET_SCHEDULER_cancel (pp->task);
339 pp->task = GNUNET_SCHEDULER_add_now (&schedule_peer_transmission, pp);
345 * Get the pending request with the highest TTL from the given plan.
347 * @param rp plan to investigate
348 * @return pending request with highest TTL
350 struct GSF_PendingRequest *
351 get_latest (const struct GSF_RequestPlan *rp)
353 struct GSF_PendingRequest *ret;
354 struct PendingRequestList *prl;
361 if (GSF_pending_request_get_data_ (prl->pr)->ttl.abs_value >
362 GSF_pending_request_get_data_ (ret)->ttl.abs_value)
371 * Function called to get a message for transmission.
374 * @param buf_size number of bytes available in buf
375 * @param buf where to copy the message, NULL on error (peer disconnect)
376 * @return number of bytes copied to 'buf', can be 0 (without indicating an error)
379 transmit_message_callback (void *cls, size_t buf_size, void *buf)
381 struct PeerPlan *pp = cls;
382 struct GSF_RequestPlan *rp;
388 /* failed, try again... */
389 pp->task = GNUNET_SCHEDULER_add_now (&schedule_peer_transmission, pp);
390 GNUNET_STATISTICS_update (GSF_stats,
392 ("# transmission failed (core has no bandwidth)"),
396 rp = GNUNET_CONTAINER_heap_peek (pp->priority_heap);
399 pp->task = GNUNET_SCHEDULER_add_now (&schedule_peer_transmission, pp);
402 msize = GSF_pending_request_get_message_ (get_latest (rp), buf_size, buf);
403 if (msize > buf_size)
405 /* buffer to small (message changed), try again */
406 pp->task = GNUNET_SCHEDULER_add_now (&schedule_peer_transmission, pp);
409 /* remove from root, add again elsewhere... */
410 GNUNET_assert (rp == GNUNET_CONTAINER_heap_remove_root (pp->priority_heap));
412 rp->last_transmission = GNUNET_TIME_absolute_get ();
413 rp->transmission_counter++;
416 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
417 "Executing plan %p executed %u times, planning retransmission\n",
418 rp, rp->transmission_counter);
421 GNUNET_STATISTICS_update (GSF_stats,
423 ("# query messages sent to other peers"), 1,
430 * Figure out when and how to transmit to the given peer.
432 * @param cls the 'struct PeerPlan'
433 * @param tc scheduler context
436 schedule_peer_transmission (void *cls,
437 const struct GNUNET_SCHEDULER_TaskContext *tc)
439 struct PeerPlan *pp = cls;
440 struct GSF_RequestPlan *rp;
442 struct GNUNET_TIME_Relative delay;
444 pp->task = GNUNET_SCHEDULER_NO_TASK;
447 GSF_peer_transmit_cancel_ (pp->pth);
450 /* move ready requests to priority queue */
451 while ((NULL != (rp = GNUNET_CONTAINER_heap_peek (pp->delay_heap))) &&
452 (GNUNET_TIME_absolute_get_remaining
453 (rp->earliest_transmission).rel_value == 0))
455 GNUNET_assert (rp == GNUNET_CONTAINER_heap_remove_root (pp->delay_heap));
456 rp->hn = GNUNET_CONTAINER_heap_insert (pp->priority_heap, rp, rp->priority);
458 if (0 == GNUNET_CONTAINER_heap_get_size (pp->priority_heap))
460 /* priority heap (still) empty, check for delay... */
461 rp = GNUNET_CONTAINER_heap_peek (pp->delay_heap);
465 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "No active requests for plan %p.\n",
468 return; /* both queues empty */
470 delay = GNUNET_TIME_absolute_get_remaining (rp->earliest_transmission);
472 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
473 "Sleeping for %llu ms before retrying requests on plan %p.\n",
474 (unsigned long long) delay.rel_value, pp);
476 GNUNET_STATISTICS_set (GSF_stats, gettext_noop ("# delay heap timeout"),
477 delay.rel_value, GNUNET_NO);
480 GNUNET_SCHEDULER_add_delayed (delay, &schedule_peer_transmission, pp);
483 GNUNET_STATISTICS_update (GSF_stats, gettext_noop ("# query plans executed"),
485 /* process from priority heap */
486 rp = GNUNET_CONTAINER_heap_peek (pp->priority_heap);
488 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Executing query plan %p\n", rp);
490 GNUNET_assert (NULL != rp);
491 msize = GSF_pending_request_get_message_ (get_latest (rp), 0, NULL);
493 GSF_peer_transmit_ (pp->cp, GNUNET_YES, rp->priority,
494 GNUNET_TIME_UNIT_FOREVER_REL, msize,
495 &transmit_message_callback, pp);
496 GNUNET_assert (NULL != pp->pth);
501 * Closure for 'merge_pr'.
506 struct GSF_PendingRequest *pr;
514 * Iterator that checks if an equivalent request is already
515 * present for this peer.
518 * @param query the query
519 * @param element request plan stored at the node
520 * @return GNUNET_YES if we should continue to iterate,
521 * GNUNET_NO if not (merge success)
524 merge_pr (void *cls, const GNUNET_HashCode * query, void *element)
526 struct MergeContext *mpr = cls;
527 struct GSF_RequestPlan *rp = element;
528 struct GSF_PendingRequestData *prd;
529 struct GSF_RequestPlanReference *rpr;
530 struct PendingRequestList *prl;
531 struct GSF_PendingRequest *latest;
534 GSF_pending_request_is_compatible_ (mpr->pr, rp->prl_head->pr))
536 /* merge new request with existing request plan */
537 rpr = GNUNET_malloc (sizeof (struct GSF_RequestPlanReference));
538 prl = GNUNET_malloc (sizeof (struct PendingRequestList));
543 prd = GSF_pending_request_get_data_ (mpr->pr);
544 GNUNET_CONTAINER_DLL_insert (prd->rpr_head, prd->rpr_tail, rpr);
545 GNUNET_CONTAINER_DLL_insert (rp->prl_head, rp->prl_tail, prl);
546 mpr->merged = GNUNET_YES;
547 GNUNET_STATISTICS_update (GSF_stats, gettext_noop ("# requests merged"), 1,
549 latest = get_latest (rp);
550 if (GSF_pending_request_get_data_ (latest)->ttl.abs_value <
553 GNUNET_STATISTICS_update (GSF_stats, gettext_noop ("# requests refreshed"),
555 rp->transmission_counter = 0; /* reset */
562 * Create a new query plan entry.
564 * @param cp peer with the entry
565 * @param pr request with the entry
568 GSF_plan_add_ (struct GSF_ConnectedPeer *cp, struct GSF_PendingRequest *pr)
570 struct GNUNET_PeerIdentity id;
572 struct GSF_PendingRequestData *prd;
573 struct GSF_RequestPlan *rp;
574 struct GSF_RequestPlanReference *rpr;
575 struct PendingRequestList *prl;
576 struct MergeContext mpc;
578 GNUNET_assert (NULL != cp);
579 GSF_connected_peer_get_identity_ (cp, &id);
580 pp = GNUNET_CONTAINER_multihashmap_get (plans, &id.hashPubKey);
583 pp = GNUNET_malloc (sizeof (struct PeerPlan));
584 pp->plan_map = GNUNET_CONTAINER_multihashmap_create (128);
586 GNUNET_CONTAINER_heap_create (GNUNET_CONTAINER_HEAP_ORDER_MAX);
588 GNUNET_CONTAINER_heap_create (GNUNET_CONTAINER_HEAP_ORDER_MIN);
590 GNUNET_CONTAINER_multihashmap_put (plans, &id.hashPubKey, pp,
591 GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY);
593 mpc.merged = GNUNET_NO;
595 GNUNET_CONTAINER_multihashmap_get_multiple (pp->plan_map,
596 &GSF_pending_request_get_data_
597 (pr)->query, &merge_pr, &mpc);
598 if (mpc.merged != GNUNET_NO)
600 GNUNET_CONTAINER_multihashmap_get_multiple (pp->plan_map,
601 &GSF_pending_request_get_data_
602 (pr)->query, &merge_pr, &mpc);
603 if (mpc.merged != GNUNET_NO)
606 GNUNET_STATISTICS_update (GSF_stats, gettext_noop ("# query plan entries"), 1,
608 prd = GSF_pending_request_get_data_ (pr);
610 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
611 "Planning transmission of query `%s' to peer `%s'\n",
612 GNUNET_h2s (&prd->query), GNUNET_i2s (&id));
614 rp = GNUNET_malloc (sizeof (struct GSF_RequestPlan));
615 rpr = GNUNET_malloc (sizeof (struct GSF_RequestPlanReference));
616 prl = GNUNET_malloc (sizeof (struct PendingRequestList));
621 GNUNET_CONTAINER_DLL_insert (prd->rpr_head, prd->rpr_tail, rpr);
622 GNUNET_CONTAINER_DLL_insert (rp->prl_head, rp->prl_tail, prl);
624 GNUNET_assert (GNUNET_YES ==
625 GNUNET_CONTAINER_multihashmap_put (pp->plan_map,
627 GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE));
633 * Notify the plan about a peer being no longer available;
634 * destroy all entries associated with this peer.
636 * @param cp connected peer
639 GSF_plan_notify_peer_disconnect_ (const struct GSF_ConnectedPeer *cp)
641 struct GNUNET_PeerIdentity id;
643 struct GSF_RequestPlan *rp;
644 struct GSF_PendingRequestData *prd;
645 struct PendingRequestList *prl;
647 GSF_connected_peer_get_identity_ (cp, &id);
648 pp = GNUNET_CONTAINER_multihashmap_get (plans, &id.hashPubKey);
650 return; /* nothing was ever planned for this peer */
651 GNUNET_assert (GNUNET_YES ==
652 GNUNET_CONTAINER_multihashmap_remove (plans, &id.hashPubKey,
655 GSF_peer_transmit_cancel_ (pp->pth);
656 if (GNUNET_SCHEDULER_NO_TASK != pp->task)
658 GNUNET_SCHEDULER_cancel (pp->task);
659 pp->task = GNUNET_SCHEDULER_NO_TASK;
661 while (NULL != (rp = GNUNET_CONTAINER_heap_remove_root (pp->priority_heap)))
663 GNUNET_break (GNUNET_YES ==
664 GNUNET_CONTAINER_multihashmap_remove (pp->plan_map,
665 get_rp_key (rp), rp));
666 while (NULL != (prl = rp->prl_head))
668 GNUNET_CONTAINER_DLL_remove (rp->prl_head, rp->prl_tail, prl);
669 prd = GSF_pending_request_get_data_ (prl->pr);
670 GNUNET_CONTAINER_DLL_remove (prd->rpr_head, prd->rpr_tail, prl->rpr);
671 GNUNET_free (prl->rpr);
676 GNUNET_CONTAINER_heap_destroy (pp->priority_heap);
677 while (NULL != (rp = GNUNET_CONTAINER_heap_remove_root (pp->delay_heap)))
679 GNUNET_break (GNUNET_YES ==
680 GNUNET_CONTAINER_multihashmap_remove (pp->plan_map,
681 get_rp_key (rp), rp));
682 while (NULL != (prl = rp->prl_head))
684 GNUNET_CONTAINER_DLL_remove (rp->prl_head, rp->prl_tail, prl);
685 prd = GSF_pending_request_get_data_ (prl->pr);
686 GNUNET_CONTAINER_DLL_remove (prd->rpr_head, prd->rpr_tail, prl->rpr);
687 GNUNET_free (prl->rpr);
692 GNUNET_STATISTICS_set (GSF_stats, gettext_noop ("# query plan entries"),
693 plan_count, GNUNET_NO);
695 GNUNET_CONTAINER_heap_destroy (pp->delay_heap);
696 GNUNET_CONTAINER_multihashmap_destroy (pp->plan_map);
702 * Notify the plan about a request being done; destroy all entries
703 * associated with this request.
705 * @param pr request that is done
708 GSF_plan_notify_request_done_ (struct GSF_PendingRequest *pr)
710 struct GSF_RequestPlan *rp;
711 struct GSF_PendingRequestData *prd;
712 struct GSF_RequestPlanReference *rpr;
714 prd = GSF_pending_request_get_data_ (pr);
715 while (NULL != (rpr = prd->rpr_head))
717 GNUNET_CONTAINER_DLL_remove (prd->rpr_head, prd->rpr_tail, rpr);
719 GNUNET_CONTAINER_DLL_remove (rp->prl_head, rp->prl_tail, rpr->prl);
720 if (NULL == rp->prl_head)
722 GNUNET_CONTAINER_heap_remove_node (rp->hn);
724 GNUNET_break (GNUNET_YES ==
725 GNUNET_CONTAINER_multihashmap_remove (rp->pp->plan_map,
726 &GSF_pending_request_get_data_
727 (rpr->prl->pr)->query,
731 GNUNET_free (rpr->prl);
734 GNUNET_STATISTICS_set (GSF_stats, gettext_noop ("# query plan entries"),
735 plan_count, GNUNET_NO);
740 * Initialize plan subsystem.
745 plans = GNUNET_CONTAINER_multihashmap_create (256);
750 * Shutdown plan subsystem.
755 GNUNET_assert (0 == GNUNET_CONTAINER_multihashmap_size (plans));
756 GNUNET_CONTAINER_multihashmap_destroy (plans);
761 /* end of gnunet-service-fs_pe.h */