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3 Copyright (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"
33 * Collect an instane number of statistics? May cause excessive IPC.
35 #define INSANE_STATISTICS GNUNET_NO
38 * List of GSF_PendingRequests this request plan
41 struct PendingRequestList;
44 * Transmission plan for a peer.
50 * M:N binding of plans to pending requests.
51 * Each pending request can be in a number of plans,
52 * and each plan can have a number of pending requests.
53 * Objects of this type indicate a mapping of a plan to
54 * a particular pending request.
56 * The corresponding head and tail of the "PE" MDLL
57 * are stored in a `struct GSF_RequestPlan`. (We need
58 * to be able to lookup all pending requests corresponding
59 * to a given plan entry.)
61 * Similarly head and tail of the "PR" MDLL are stored
62 * with the `struct GSF_PendingRequest`. (We need
63 * to be able to lookup all plan entries corresponding
64 * to a given pending request.)
66 struct GSF_PendingRequestPlanBijection
70 * This is a doubly-linked list.
72 struct GSF_PendingRequestPlanBijection *next_PR;
75 * This is a doubly-linked list.
77 struct GSF_PendingRequestPlanBijection *prev_PR;
80 * This is a doubly-linked list.
82 struct GSF_PendingRequestPlanBijection *next_PE;
85 * This is a doubly-linked list.
87 struct GSF_PendingRequestPlanBijection *prev_PE;
90 * Associated request plan (tells us one of the peers that
91 * we plan to forward the request to).
93 struct GSF_RequestPlan *rp;
96 * Associated pending request (identifies request details
97 * and one of the origins of the request).
99 struct GSF_PendingRequest *pr;
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. This tells us
135 * which incoming requests from other peers this plan entry
138 struct GSF_PendingRequestPlanBijection *pe_head;
141 * Tail of list of associated pending requests.
143 struct GSF_PendingRequestPlanBijection *pe_tail;
146 * Earliest time we'd be happy to (re)transmit this request.
148 struct GNUNET_TIME_Absolute earliest_transmission;
151 * When was the last time we transmitted this request to this peer? 0 for never.
153 struct GNUNET_TIME_Absolute last_transmission;
156 * Current priority for this request for this target.
161 * How often did we transmit this request to this peer?
163 unsigned int transmission_counter;
169 * Transmission plan for a peer.
174 * Heap with pending queries (`struct GSF_RequestPlan`), higher weights mean higher priority.
176 struct GNUNET_CONTAINER_Heap *priority_heap;
179 * Heap with pending queries (`struct GSF_RequestPlan`), by transmission time, lowest first.
181 struct GNUNET_CONTAINER_Heap *delay_heap;
184 * Map of queries to plan entries. All entries in the @e priority_heap
185 * or @e delay_heap should be in the @e plan_map. Note that it is
186 * possible for the @e plan_map to have multiple entries for the same
189 struct GNUNET_CONTAINER_MultiHashMap *plan_map;
192 * Current transmission request handle.
194 struct GSF_PeerTransmitHandle *pth;
197 * Peer for which this is the plan.
199 struct GSF_ConnectedPeer *cp;
202 * Current task for executing the plan.
204 struct GNUNET_SCHEDULER_Task *task;
209 * Hash map from peer identities to PeerPlans.
211 static struct GNUNET_CONTAINER_MultiPeerMap *plans;
214 * Sum of all transmission counters (equals total delay for all plan entries).
216 static unsigned long long total_delay;
219 * Number of plan entries.
221 static unsigned long long plan_count;
225 * Return the query (key in the plan_map) for the given request plan.
226 * Note that this key may change as there can be multiple pending
227 * requests for the same key and we just return _one_ of them; this
228 * particular one might complete while another one might still be
229 * active, hence the lifetime of the returned hash code is NOT
230 * necessarily identical to that of the `struct GSF_RequestPlan`
233 * @param rp a request plan
234 * @return the associated query
236 static const struct GNUNET_HashCode *
237 get_rp_key (struct GSF_RequestPlan *rp)
239 return &GSF_pending_request_get_data_ (rp->pe_head->pr)->query;
244 * Figure out when and how to transmit to the given peer.
246 * @param cls the `struct GSF_ConnectedPeer` for transmission
247 * @param tc scheduler context
250 schedule_peer_transmission (void *cls,
251 const struct GNUNET_SCHEDULER_TaskContext *tc);
255 * Insert the given request plan into the heap with the appropriate weight.
257 * @param pp associated peer's plan
258 * @param rp request to plan
261 plan (struct PeerPlan *pp,
262 struct GSF_RequestPlan *rp)
264 #define N ((double)128.0)
266 * Running average delay we currently impose.
268 static double avg_delay;
270 struct GSF_PendingRequestData *prd;
271 struct GNUNET_TIME_Relative delay;
273 GNUNET_assert (rp->pp == pp);
274 GNUNET_STATISTICS_set (GSF_stats,
275 gettext_noop ("# average retransmission delay (ms)"),
276 total_delay * 1000LL / plan_count, GNUNET_NO);
277 prd = GSF_pending_request_get_data_ (rp->pe_head->pr);
279 if (rp->transmission_counter < 8)
281 GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS,
282 rp->transmission_counter);
283 else if (rp->transmission_counter < 32)
285 GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS,
287 (1LL << (rp->transmission_counter - 8)));
290 GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS,
293 GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK,
294 delay.rel_value_us + 1);
295 /* Add 0.01 to avg_delay to avoid division-by-zero later */
296 avg_delay = (((avg_delay * (N - 1.0)) + delay.rel_value_us) / N) + 0.01;
299 * For the priority, we need to consider a few basic rules:
300 * 1) if we just started requesting (delay is small), we should
301 * virtually always have a priority of zero.
302 * 2) for requests with average latency, our priority should match
303 * the average priority observed on the network
304 * 3) even the longest-running requests should not be WAY out of
305 * the observed average (thus we bound by a factor of 2)
306 * 4) we add +1 to the observed average priority to avoid everyone
307 * staying put at zero (2 * 0 = 0...).
309 * Using the specific calculation below, we get:
311 * delay = 0 => priority = 0;
312 * delay = avg delay => priority = running-average-observed-priority;
313 * delay >> avg_delay => priority = 2 * running-average-observed-priority;
315 * which satisfies all of the rules above.
317 * Note: M_PI_4 = PI/4 = arctan(1)
320 round ((GSF_current_priorities +
321 1.0) * atan (delay.rel_value_us / avg_delay)) / M_PI_4;
322 /* Note: usage of 'round' and 'atan' requires -lm */
324 if (rp->transmission_counter != 0)
325 delay.rel_value_us += TTL_DECREMENT * 1000;
326 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
327 "Considering (re)transmission number %u in %s\n",
328 (unsigned int) rp->transmission_counter,
329 GNUNET_STRINGS_relative_time_to_string (delay,
331 rp->earliest_transmission = GNUNET_TIME_relative_to_absolute (delay);
332 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
333 "Earliest (re)transmission for `%s' in %us\n",
334 GNUNET_h2s (&prd->query), rp->transmission_counter);
335 GNUNET_assert (rp->hn == NULL);
336 if (0 == GNUNET_TIME_absolute_get_remaining (rp->earliest_transmission).rel_value_us)
337 rp->hn = GNUNET_CONTAINER_heap_insert (pp->priority_heap, rp, rp->priority);
340 GNUNET_CONTAINER_heap_insert (pp->delay_heap, rp,
341 rp->earliest_transmission.abs_value_us);
342 GNUNET_assert (GNUNET_YES ==
343 GNUNET_CONTAINER_multihashmap_contains_value (pp->plan_map,
346 if (NULL != pp->task)
347 GNUNET_SCHEDULER_cancel (pp->task);
348 pp->task = GNUNET_SCHEDULER_add_now (&schedule_peer_transmission, pp);
354 * Get the pending request with the highest TTL from the given plan.
356 * @param rp plan to investigate
357 * @return pending request with highest TTL
359 struct GSF_PendingRequest *
360 get_latest (const struct GSF_RequestPlan *rp)
362 struct GSF_PendingRequest *ret;
363 struct GSF_PendingRequestPlanBijection *bi;
364 const struct GSF_PendingRequestData *rprd;
365 const struct GSF_PendingRequestData *prd;
369 return NULL; /* should never happen */
371 rprd = GSF_pending_request_get_data_ (ret);
372 for (bi = bi->next_PE; NULL != bi; bi = bi->next_PE)
374 prd = GSF_pending_request_get_data_ (bi->pr);
375 if (prd->ttl.abs_value_us > rprd->ttl.abs_value_us)
386 * Function called to get a message for transmission.
389 * @param buf_size number of bytes available in @a buf
390 * @param buf where to copy the message, NULL on error (peer disconnect)
391 * @return number of bytes copied to @a buf, can be 0 (without indicating an error)
394 transmit_message_callback (void *cls,
398 struct PeerPlan *pp = cls;
399 struct GSF_RequestPlan *rp;
405 /* failed, try again... */
406 if (NULL != pp->task)
407 GNUNET_SCHEDULER_cancel (pp->task);
409 pp->task = GNUNET_SCHEDULER_add_now (&schedule_peer_transmission, pp);
410 GNUNET_STATISTICS_update (GSF_stats,
412 ("# transmission failed (core has no bandwidth)"),
416 rp = GNUNET_CONTAINER_heap_peek (pp->priority_heap);
419 if (NULL != pp->task)
420 GNUNET_SCHEDULER_cancel (pp->task);
421 pp->task = GNUNET_SCHEDULER_add_now (&schedule_peer_transmission, pp);
424 msize = GSF_pending_request_get_message_ (get_latest (rp),
427 if (msize > buf_size)
429 if (NULL != pp->task)
430 GNUNET_SCHEDULER_cancel (pp->task);
431 /* buffer to small (message changed), try again */
432 pp->task = GNUNET_SCHEDULER_add_now (&schedule_peer_transmission, pp);
435 /* remove from root, add again elsewhere... */
436 GNUNET_assert (rp == GNUNET_CONTAINER_heap_remove_root (pp->priority_heap));
438 rp->last_transmission = GNUNET_TIME_absolute_get ();
439 rp->transmission_counter++;
441 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
442 "Executing plan %p executed %u times, planning retransmission\n",
443 rp, rp->transmission_counter);
445 GNUNET_STATISTICS_update (GSF_stats,
447 ("# query messages sent to other peers"), 1,
454 * Figure out when and how to transmit to the given peer.
456 * @param cls the `struct PeerPlan`
457 * @param tc scheduler context
460 schedule_peer_transmission (void *cls,
461 const struct GNUNET_SCHEDULER_TaskContext *tc)
463 struct PeerPlan *pp = cls;
464 struct GSF_RequestPlan *rp;
466 struct GNUNET_TIME_Relative delay;
471 GSF_peer_transmit_cancel_ (pp->pth);
474 /* move ready requests to priority queue */
475 while ((NULL != (rp = GNUNET_CONTAINER_heap_peek (pp->delay_heap))) &&
476 (0 == GNUNET_TIME_absolute_get_remaining
477 (rp->earliest_transmission).rel_value_us))
479 GNUNET_assert (rp == GNUNET_CONTAINER_heap_remove_root (pp->delay_heap));
480 rp->hn = GNUNET_CONTAINER_heap_insert (pp->priority_heap, rp, rp->priority);
482 if (0 == GNUNET_CONTAINER_heap_get_size (pp->priority_heap))
484 /* priority heap (still) empty, check for delay... */
485 rp = GNUNET_CONTAINER_heap_peek (pp->delay_heap);
488 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
489 "No active requests for plan %p.\n",
491 return; /* both queues empty */
493 delay = GNUNET_TIME_absolute_get_remaining (rp->earliest_transmission);
494 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
495 "Sleeping for %s before retrying requests on plan %p.\n",
496 GNUNET_STRINGS_relative_time_to_string (delay,
499 GNUNET_STATISTICS_set (GSF_stats,
500 gettext_noop ("# delay heap timeout (ms)"),
501 delay.rel_value_us / 1000LL, GNUNET_NO);
504 GNUNET_SCHEDULER_add_delayed (delay,
505 &schedule_peer_transmission,
509 #if INSANE_STATISTICS
510 GNUNET_STATISTICS_update (GSF_stats, gettext_noop ("# query plans executed"),
513 /* process from priority heap */
514 rp = GNUNET_CONTAINER_heap_peek (pp->priority_heap);
515 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Executing query plan %p\n", rp);
516 GNUNET_assert (NULL != rp);
517 msize = GSF_pending_request_get_message_ (get_latest (rp), 0, NULL);
519 GSF_peer_transmit_ (pp->cp, GNUNET_YES,
521 GNUNET_TIME_UNIT_FOREVER_REL,
523 &transmit_message_callback, pp);
524 GNUNET_assert (NULL != pp->pth);
529 * Closure for merge_pr().
535 * Request we are trying to merge.
537 struct GSF_PendingRequest *pr;
540 * Set to #GNUNET_YES if we succeeded to merge.
548 * Iterator that checks if an equivalent request is already
549 * present for this peer.
552 * @param query the query
553 * @param element request plan stored at the node
554 * @return #GNUNET_YES if we should continue to iterate,
555 * #GNUNET_NO if not (merge success)
559 const struct GNUNET_HashCode *query,
562 struct MergeContext *mpr = cls;
563 struct GSF_RequestPlan *rp = element;
564 struct GSF_PendingRequestData *prd;
565 struct GSF_PendingRequestPlanBijection *bi;
566 struct GSF_PendingRequest *latest;
569 GSF_pending_request_is_compatible_ (mpr->pr,
572 /* merge new request with existing request plan */
573 bi = GNUNET_new (struct GSF_PendingRequestPlanBijection);
576 prd = GSF_pending_request_get_data_ (mpr->pr);
577 GNUNET_CONTAINER_MDLL_insert (PR,
581 GNUNET_CONTAINER_MDLL_insert (PE,
585 mpr->merged = GNUNET_YES;
586 #if INSANE_STATISTICS
587 GNUNET_STATISTICS_update (GSF_stats,
588 gettext_noop ("# requests merged"), 1,
591 latest = get_latest (rp);
592 if (GSF_pending_request_get_data_ (latest)->ttl.abs_value_us <
593 prd->ttl.abs_value_us)
595 #if INSANE_STATISTICS
596 GNUNET_STATISTICS_update (GSF_stats,
597 gettext_noop ("# requests refreshed"),
600 rp->transmission_counter = 0; /* reset */
607 * Create a new query plan entry.
609 * @param cp peer with the entry
610 * @param pr request with the entry
613 GSF_plan_add_ (struct GSF_ConnectedPeer *cp,
614 struct GSF_PendingRequest *pr)
616 const struct GNUNET_PeerIdentity *id;
618 struct GSF_PendingRequestData *prd;
619 struct GSF_RequestPlan *rp;
620 struct GSF_PendingRequestPlanBijection *bi;
621 struct MergeContext mpc;
623 GNUNET_assert (NULL != cp);
624 id = GSF_connected_peer_get_identity2_ (cp);
625 pp = GNUNET_CONTAINER_multipeermap_get (plans, id);
628 pp = GNUNET_new (struct PeerPlan);
629 pp->plan_map = GNUNET_CONTAINER_multihashmap_create (128, GNUNET_NO);
631 GNUNET_CONTAINER_heap_create (GNUNET_CONTAINER_HEAP_ORDER_MAX);
633 GNUNET_CONTAINER_heap_create (GNUNET_CONTAINER_HEAP_ORDER_MIN);
635 GNUNET_assert (GNUNET_OK ==
636 GNUNET_CONTAINER_multipeermap_put (plans,
639 GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
641 mpc.merged = GNUNET_NO;
643 prd = GSF_pending_request_get_data_ (pr);
644 GNUNET_CONTAINER_multihashmap_get_multiple (pp->plan_map,
648 if (GNUNET_NO != mpc.merged)
651 GNUNET_STATISTICS_update (GSF_stats,
652 gettext_noop ("# query plan entries"),
655 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
656 "Planning transmission of query `%s' to peer `%s'\n",
657 GNUNET_h2s (&prd->query),
659 rp = GNUNET_new (struct GSF_RequestPlan);
660 bi = GNUNET_new (struct GSF_PendingRequestPlanBijection);
663 GNUNET_CONTAINER_MDLL_insert (PR,
667 GNUNET_CONTAINER_MDLL_insert (PE,
672 GNUNET_assert (GNUNET_YES ==
673 GNUNET_CONTAINER_multihashmap_put (pp->plan_map,
676 GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE));
683 * Notify the plan about a peer being no longer available;
684 * destroy all entries associated with this peer.
686 * @param cp connected peer
689 GSF_plan_notify_peer_disconnect_ (const struct GSF_ConnectedPeer *cp)
691 const struct GNUNET_PeerIdentity *id;
693 struct GSF_RequestPlan *rp;
694 struct GSF_PendingRequestData *prd;
695 struct GSF_PendingRequestPlanBijection *bi;
697 id = GSF_connected_peer_get_identity2_ (cp);
698 pp = GNUNET_CONTAINER_multipeermap_get (plans, id);
700 return; /* nothing was ever planned for this peer */
701 GNUNET_assert (GNUNET_YES ==
702 GNUNET_CONTAINER_multipeermap_remove (plans, id,
706 GSF_peer_transmit_cancel_ (pp->pth);
709 if (NULL != pp->task)
711 GNUNET_SCHEDULER_cancel (pp->task);
714 while (NULL != (rp = GNUNET_CONTAINER_heap_remove_root (pp->priority_heap)))
716 GNUNET_break (GNUNET_YES ==
717 GNUNET_CONTAINER_multihashmap_remove (pp->plan_map,
718 get_rp_key (rp), rp));
719 while (NULL != (bi = rp->pe_head))
721 GNUNET_CONTAINER_MDLL_remove (PE, rp->pe_head, rp->pe_tail, bi);
722 prd = GSF_pending_request_get_data_ (bi->pr);
723 GNUNET_CONTAINER_MDLL_remove (PR, prd->pr_head, prd->pr_tail, bi);
729 GNUNET_CONTAINER_heap_destroy (pp->priority_heap);
730 while (NULL != (rp = GNUNET_CONTAINER_heap_remove_root (pp->delay_heap)))
732 GNUNET_break (GNUNET_YES ==
733 GNUNET_CONTAINER_multihashmap_remove (pp->plan_map,
734 get_rp_key (rp), rp));
735 while (NULL != (bi = rp->pe_head))
737 prd = GSF_pending_request_get_data_ (bi->pr);
738 GNUNET_CONTAINER_MDLL_remove (PE, rp->pe_head, rp->pe_tail, bi);
739 GNUNET_CONTAINER_MDLL_remove (PR, prd->pr_head, prd->pr_tail, bi);
745 GNUNET_STATISTICS_set (GSF_stats, gettext_noop ("# query plan entries"),
746 plan_count, GNUNET_NO);
747 GNUNET_CONTAINER_heap_destroy (pp->delay_heap);
748 GNUNET_CONTAINER_multihashmap_destroy (pp->plan_map);
754 * Get the last transmission attempt time for the request plan list
755 * referenced by @a pr_head, that was sent to @a sender
757 * @param pr_head request plan reference list to check.
758 * @param sender the peer that we've sent the request to.
759 * @param result the timestamp to fill, set to #GNUNET_TIME_UNIT_FOREVER_ABS if never transmitted
760 * @return #GNUNET_YES if @a result was changed, #GNUNET_NO otherwise.
763 GSF_request_plan_reference_get_last_transmission_ (struct GSF_PendingRequestPlanBijection *pr_head,
764 struct GSF_ConnectedPeer *sender,
765 struct GNUNET_TIME_Absolute *result)
767 struct GSF_PendingRequestPlanBijection *bi;
769 for (bi = pr_head; NULL != bi; bi = bi->next_PR)
771 if (bi->rp->pp->cp == sender)
773 if (0 == bi->rp->last_transmission.abs_value_us)
774 *result = GNUNET_TIME_UNIT_FOREVER_ABS;
776 *result = bi->rp->last_transmission;
785 * Notify the plan about a request being done; destroy all entries
786 * associated with this request.
788 * @param pr request that is done
791 GSF_plan_notify_request_done_ (struct GSF_PendingRequest *pr)
793 struct GSF_RequestPlan *rp;
794 struct GSF_PendingRequestData *prd;
795 struct GSF_PendingRequestPlanBijection *bi;
797 prd = GSF_pending_request_get_data_ (pr);
798 while (NULL != (bi = prd->pr_head))
801 GNUNET_CONTAINER_MDLL_remove (PR, prd->pr_head, prd->pr_tail, bi);
802 GNUNET_CONTAINER_MDLL_remove (PE, rp->pe_head, rp->pe_tail, bi);
803 if (NULL == rp->pe_head)
805 GNUNET_CONTAINER_heap_remove_node (rp->hn);
807 GNUNET_break (GNUNET_YES ==
808 GNUNET_CONTAINER_multihashmap_remove (rp->pp->plan_map,
809 &GSF_pending_request_get_data_
816 GNUNET_STATISTICS_set (GSF_stats, gettext_noop ("# query plan entries"),
817 plan_count, GNUNET_NO);
822 * Initialize plan subsystem.
827 plans = GNUNET_CONTAINER_multipeermap_create (256, GNUNET_YES);
832 * Shutdown plan subsystem.
837 GNUNET_assert (0 == GNUNET_CONTAINER_multipeermap_size (plans));
838 GNUNET_CONTAINER_multipeermap_destroy (plans);
843 /* end of gnunet-service-fs_pe.h */