/* This file is part of GNUnet. Copyright (C) 2011 GNUnet e.V. GNUnet is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. GNUnet is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details. You should have received a copy of the GNU Affero General Public License along with this program. If not, see . SPDX-License-Identifier: AGPL3.0-or-later */ /** * @file fs/gnunet-service-fs_pe.c * @brief API to manage query plan * @author Christian Grothoff */ #include "platform.h" #include "gnunet-service-fs.h" #include "gnunet-service-fs_cp.h" #include "gnunet-service-fs_pe.h" #include "gnunet-service-fs_pr.h" /** * Collect an instane number of statistics? May cause excessive IPC. */ #define INSANE_STATISTICS GNUNET_NO /** * List of GSF_PendingRequests this request plan * participates with. */ struct PendingRequestList; /** * Transmission plan for a peer. */ struct PeerPlan; /** * M:N binding of plans to pending requests. * Each pending request can be in a number of plans, * and each plan can have a number of pending requests. * Objects of this type indicate a mapping of a plan to * a particular pending request. * * The corresponding head and tail of the "PE" MDLL * are stored in a `struct GSF_RequestPlan`. (We need * to be able to lookup all pending requests corresponding * to a given plan entry.) * * Similarly head and tail of the "PR" MDLL are stored * with the `struct GSF_PendingRequest`. (We need * to be able to lookup all plan entries corresponding * to a given pending request.) */ struct GSF_PendingRequestPlanBijection { /** * This is a doubly-linked list. */ struct GSF_PendingRequestPlanBijection *next_PR; /** * This is a doubly-linked list. */ struct GSF_PendingRequestPlanBijection *prev_PR; /** * This is a doubly-linked list. */ struct GSF_PendingRequestPlanBijection *next_PE; /** * This is a doubly-linked list. */ struct GSF_PendingRequestPlanBijection *prev_PE; /** * Associated request plan (tells us one of the peers that * we plan to forward the request to). */ struct GSF_RequestPlan *rp; /** * Associated pending request (identifies request details * and one of the origins of the request). */ struct GSF_PendingRequest *pr; }; /** * Information we keep per request per peer. This is a doubly-linked * list (with head and tail in the `struct GSF_PendingRequestData`) * with one entry in each heap of each `struct PeerPlan`. Each * entry tracks information relevant for this request and this peer. */ struct GSF_RequestPlan { /** * This is a doubly-linked list. */ struct GSF_RequestPlan *next; /** * This is a doubly-linked list. */ struct GSF_RequestPlan *prev; /** * Heap node associated with this request and this peer. */ struct GNUNET_CONTAINER_HeapNode *hn; /** * The transmission plan for a peer that this request is associated with. */ struct PeerPlan *pp; /** * Head of list of associated pending requests. This tells us * which incoming requests from other peers this plan entry * corresponds to. */ struct GSF_PendingRequestPlanBijection *pe_head; /** * Tail of list of associated pending requests. */ struct GSF_PendingRequestPlanBijection *pe_tail; /** * Earliest time we'd be happy to (re)transmit this request. */ struct GNUNET_TIME_Absolute earliest_transmission; /** * When was the last time we transmitted this request to this peer? 0 for never. */ struct GNUNET_TIME_Absolute last_transmission; /** * Current priority for this request for this target. */ uint64_t priority; /** * How often did we transmit this request to this peer? */ unsigned int transmission_counter; }; /** * Transmission plan for a peer. */ struct PeerPlan { /** * Heap with pending queries (`struct GSF_RequestPlan`), higher weights mean higher priority. */ struct GNUNET_CONTAINER_Heap *priority_heap; /** * Heap with pending queries (`struct GSF_RequestPlan`), by transmission time, lowest first. */ struct GNUNET_CONTAINER_Heap *delay_heap; /** * Map of queries to plan entries. All entries in the @e priority_heap * or @e delay_heap should be in the @e plan_map. Note that it is * possible for the @e plan_map to have multiple entries for the same * query. */ struct GNUNET_CONTAINER_MultiHashMap *plan_map; /** * Peer for which this is the plan. */ struct GSF_ConnectedPeer *cp; /** * Current task for executing the plan. */ struct GNUNET_SCHEDULER_Task *task; /** * Current message under transmission for the plan. */ struct GNUNET_MQ_Envelope *env; }; /** * Hash map from peer identities to PeerPlans. */ static struct GNUNET_CONTAINER_MultiPeerMap *plans; /** * Sum of all transmission counters (equals total delay for all plan entries). */ static unsigned long long total_delay; /** * Number of plan entries. */ static unsigned long long plan_count; /** * Return the query (key in the plan_map) for the given request plan. * Note that this key may change as there can be multiple pending * requests for the same key and we just return _one_ of them; this * particular one might complete while another one might still be * active, hence the lifetime of the returned hash code is NOT * necessarily identical to that of the `struct GSF_RequestPlan` * given. * * @param rp a request plan * @return the associated query */ static const struct GNUNET_HashCode * get_rp_key (struct GSF_RequestPlan *rp) { return &GSF_pending_request_get_data_ (rp->pe_head->pr)->query; } /** * Insert the given request plan into the heap with the appropriate weight. * * @param pp associated peer's plan * @param rp request to plan */ static void plan (struct PeerPlan *pp, struct GSF_RequestPlan *rp) { #define N ((double)128.0) /** * Running average delay we currently impose. */ static double avg_delay; struct GSF_PendingRequestData *prd; struct GNUNET_TIME_Relative delay; GNUNET_assert (rp->pp == pp); GNUNET_STATISTICS_set (GSF_stats, gettext_noop ("# average retransmission delay (ms)"), total_delay * 1000LL / plan_count, GNUNET_NO); prd = GSF_pending_request_get_data_ (rp->pe_head->pr); if (rp->transmission_counter < 8) delay = GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, rp->transmission_counter); else if (rp->transmission_counter < 32) delay = GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 8 + (1LL << (rp->transmission_counter - 8))); else delay = GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 8 + (1LL << 24)); delay.rel_value_us = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK, delay.rel_value_us + 1); /* Add 0.01 to avg_delay to avoid division-by-zero later */ avg_delay = (((avg_delay * (N - 1.0)) + delay.rel_value_us) / N) + 0.01; /* * For the priority, we need to consider a few basic rules: * 1) if we just started requesting (delay is small), we should * virtually always have a priority of zero. * 2) for requests with average latency, our priority should match * the average priority observed on the network * 3) even the longest-running requests should not be WAY out of * the observed average (thus we bound by a factor of 2) * 4) we add +1 to the observed average priority to avoid everyone * staying put at zero (2 * 0 = 0...). * * Using the specific calculation below, we get: * * delay = 0 => priority = 0; * delay = avg delay => priority = running-average-observed-priority; * delay >> avg_delay => priority = 2 * running-average-observed-priority; * * which satisfies all of the rules above. * * Note: M_PI_4 = PI/4 = arctan(1) */ rp->priority = round ((GSF_current_priorities + 1.0) * atan (delay.rel_value_us / avg_delay)) / M_PI_4; /* Note: usage of 'round' and 'atan' requires -lm */ if (rp->transmission_counter != 0) delay.rel_value_us += TTL_DECREMENT * 1000; GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Considering (re)transmission number %u in %s\n", (unsigned int) rp->transmission_counter, GNUNET_STRINGS_relative_time_to_string (delay, GNUNET_YES)); rp->earliest_transmission = GNUNET_TIME_relative_to_absolute (delay); GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Earliest (re)transmission for `%s' in %us\n", GNUNET_h2s (&prd->query), rp->transmission_counter); GNUNET_assert (rp->hn == NULL); if (0 == GNUNET_TIME_absolute_get_remaining (rp->earliest_transmission).rel_value_us) rp->hn = GNUNET_CONTAINER_heap_insert (pp->priority_heap, rp, rp->priority); else rp->hn = GNUNET_CONTAINER_heap_insert (pp->delay_heap, rp, rp->earliest_transmission.abs_value_us); GNUNET_assert (GNUNET_YES == GNUNET_CONTAINER_multihashmap_contains_value (pp->plan_map, get_rp_key (rp), rp)); #undef N } /** * Get the pending request with the highest TTL from the given plan. * * @param rp plan to investigate * @return pending request with highest TTL */ struct GSF_PendingRequest * get_latest (const struct GSF_RequestPlan *rp) { struct GSF_PendingRequest *ret; struct GSF_PendingRequestPlanBijection *bi; const struct GSF_PendingRequestData *rprd; const struct GSF_PendingRequestData *prd; bi = rp->pe_head; if (NULL == bi) return NULL; /* should never happen */ ret = bi->pr; rprd = GSF_pending_request_get_data_ (ret); for (bi = bi->next_PE; NULL != bi; bi = bi->next_PE) { GNUNET_break (GNUNET_YES == GSF_pending_request_test_active_ (bi->pr)); prd = GSF_pending_request_get_data_ (bi->pr); if (prd->ttl.abs_value_us > rprd->ttl.abs_value_us) { ret = bi->pr; rprd = prd; } } return ret; } /** * Figure out when and how to transmit to the given peer. * * @param cls the `struct PeerPlan` */ static void schedule_peer_transmission (void *cls) { struct PeerPlan *pp = cls; struct GSF_RequestPlan *rp; struct GNUNET_TIME_Relative delay; if (NULL != pp->task) { pp->task = NULL; } else { GNUNET_assert (NULL != pp->env); pp->env = NULL; } /* move ready requests to priority queue */ while ((NULL != (rp = GNUNET_CONTAINER_heap_peek (pp->delay_heap))) && (0 == GNUNET_TIME_absolute_get_remaining (rp->earliest_transmission).rel_value_us)) { GNUNET_assert (rp == GNUNET_CONTAINER_heap_remove_root (pp->delay_heap)); rp->hn = GNUNET_CONTAINER_heap_insert (pp->priority_heap, rp, rp->priority); } if (0 == GNUNET_CONTAINER_heap_get_size (pp->priority_heap)) { /* priority heap (still) empty, check for delay... */ rp = GNUNET_CONTAINER_heap_peek (pp->delay_heap); if (NULL == rp) { GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "No active requests for plan %p.\n", pp); return; /* both queues empty */ } delay = GNUNET_TIME_absolute_get_remaining (rp->earliest_transmission); GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Sleeping for %s before retrying requests on plan %p.\n", GNUNET_STRINGS_relative_time_to_string (delay, GNUNET_YES), pp); GNUNET_STATISTICS_set (GSF_stats, gettext_noop ("# delay heap timeout (ms)"), delay.rel_value_us / 1000LL, GNUNET_NO); pp->task = GNUNET_SCHEDULER_add_at (rp->earliest_transmission, &schedule_peer_transmission, pp); return; } #if INSANE_STATISTICS GNUNET_STATISTICS_update (GSF_stats, gettext_noop ("# query plans executed"), 1, GNUNET_NO); #endif /* process from priority heap */ rp = GNUNET_CONTAINER_heap_remove_root (pp->priority_heap); GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Executing query plan %p\n", rp); GNUNET_assert (NULL != rp); rp->hn = NULL; rp->last_transmission = GNUNET_TIME_absolute_get (); rp->transmission_counter++; total_delay++; GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Executing plan %p executed %u times, planning retransmission\n", rp, rp->transmission_counter); GNUNET_assert (NULL == pp->env); pp->env = GSF_pending_request_get_message_ (get_latest (rp)); GNUNET_MQ_notify_sent (pp->env, &schedule_peer_transmission, pp); GSF_peer_transmit_ (pp->cp, GNUNET_YES, rp->priority, pp->env); GNUNET_STATISTICS_update (GSF_stats, gettext_noop ("# query messages sent to other peers"), 1, GNUNET_NO); plan (pp, rp); } /** * Closure for merge_pr(). */ struct MergeContext { /** * Request we are trying to merge. */ struct GSF_PendingRequest *pr; /** * Set to #GNUNET_YES if we succeeded to merge. */ int merged; }; /** * Iterator that checks if an equivalent request is already * present for this peer. * * @param cls closure * @param query the query * @param element request plan stored at the node * @return #GNUNET_YES if we should continue to iterate, * #GNUNET_NO if not (merge success) */ static int merge_pr (void *cls, const struct GNUNET_HashCode *query, void *element) { struct MergeContext *mpr = cls; struct GSF_RequestPlan *rp = element; struct GSF_PendingRequestData *prd; struct GSF_PendingRequestPlanBijection *bi; struct GSF_PendingRequest *latest; GNUNET_break (GNUNET_YES == GSF_pending_request_test_active_ (mpr->pr)); if (GNUNET_OK != GSF_pending_request_is_compatible_ (mpr->pr, rp->pe_head->pr)) return GNUNET_YES; /* merge new request with existing request plan */ bi = GNUNET_new (struct GSF_PendingRequestPlanBijection); bi->rp = rp; bi->pr = mpr->pr; prd = GSF_pending_request_get_data_ (mpr->pr); GNUNET_CONTAINER_MDLL_insert (PR, prd->pr_head, prd->pr_tail, bi); GNUNET_CONTAINER_MDLL_insert (PE, rp->pe_head, rp->pe_tail, bi); mpr->merged = GNUNET_YES; #if INSANE_STATISTICS GNUNET_STATISTICS_update (GSF_stats, gettext_noop ("# requests merged"), 1, GNUNET_NO); #endif latest = get_latest (rp); if (GSF_pending_request_get_data_ (latest)->ttl.abs_value_us < prd->ttl.abs_value_us) { #if INSANE_STATISTICS GNUNET_STATISTICS_update (GSF_stats, gettext_noop ("# requests refreshed"), 1, GNUNET_NO); #endif rp->transmission_counter = 0; /* reset */ } return GNUNET_NO; } /** * Create a new query plan entry. * * @param cp peer with the entry * @param pr request with the entry */ void GSF_plan_add_ (struct GSF_ConnectedPeer *cp, struct GSF_PendingRequest *pr) { const struct GNUNET_PeerIdentity *id; struct PeerPlan *pp; struct GSF_PendingRequestData *prd; struct GSF_RequestPlan *rp; struct GSF_PendingRequestPlanBijection *bi; struct MergeContext mpc; GNUNET_assert (GNUNET_YES == GSF_pending_request_test_active_ (pr)); GNUNET_assert (NULL != cp); id = GSF_connected_peer_get_identity2_ (cp); pp = GNUNET_CONTAINER_multipeermap_get (plans, id); if (NULL == pp) { pp = GNUNET_new (struct PeerPlan); pp->plan_map = GNUNET_CONTAINER_multihashmap_create (128, GNUNET_NO); pp->priority_heap = GNUNET_CONTAINER_heap_create (GNUNET_CONTAINER_HEAP_ORDER_MAX); pp->delay_heap = GNUNET_CONTAINER_heap_create (GNUNET_CONTAINER_HEAP_ORDER_MIN); pp->cp = cp; GNUNET_assert (GNUNET_OK == GNUNET_CONTAINER_multipeermap_put (plans, id, pp, GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY)); pp->task = GNUNET_SCHEDULER_add_now (&schedule_peer_transmission, pp); } mpc.merged = GNUNET_NO; mpc.pr = pr; prd = GSF_pending_request_get_data_ (pr); GNUNET_CONTAINER_multihashmap_get_multiple (pp->plan_map, &prd->query, &merge_pr, &mpc); if (GNUNET_NO != mpc.merged) return; plan_count++; GNUNET_STATISTICS_update (GSF_stats, gettext_noop ("# query plan entries"), 1, GNUNET_NO); GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Planning transmission of query `%s' to peer `%s'\n", GNUNET_h2s (&prd->query), GNUNET_i2s (id)); rp = GNUNET_new (struct GSF_RequestPlan); bi = GNUNET_new (struct GSF_PendingRequestPlanBijection); bi->rp = rp; bi->pr = pr; GNUNET_CONTAINER_MDLL_insert (PR, prd->pr_head, prd->pr_tail, bi); GNUNET_CONTAINER_MDLL_insert (PE, rp->pe_head, rp->pe_tail, bi); rp->pp = pp; GNUNET_assert (GNUNET_YES == GNUNET_CONTAINER_multihashmap_put (pp->plan_map, get_rp_key (rp), rp, GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE)); plan (pp, rp); } /** * Notify the plan about a peer being no longer available; * destroy all entries associated with this peer. * * @param cp connected peer */ void GSF_plan_notify_peer_disconnect_ (const struct GSF_ConnectedPeer *cp) { const struct GNUNET_PeerIdentity *id; struct PeerPlan *pp; struct GSF_RequestPlan *rp; struct GSF_PendingRequestData *prd; struct GSF_PendingRequestPlanBijection *bi; id = GSF_connected_peer_get_identity2_ (cp); pp = GNUNET_CONTAINER_multipeermap_get (plans, id); if (NULL == pp) return; /* nothing was ever planned for this peer */ GNUNET_assert (GNUNET_YES == GNUNET_CONTAINER_multipeermap_remove (plans, id, pp)); if (NULL != pp->task) { GNUNET_SCHEDULER_cancel (pp->task); pp->task = NULL; } while (NULL != (rp = GNUNET_CONTAINER_heap_remove_root (pp->priority_heap))) { GNUNET_break (GNUNET_YES == GNUNET_CONTAINER_multihashmap_remove (pp->plan_map, get_rp_key (rp), rp)); while (NULL != (bi = rp->pe_head)) { GNUNET_CONTAINER_MDLL_remove (PE, rp->pe_head, rp->pe_tail, bi); prd = GSF_pending_request_get_data_ (bi->pr); GNUNET_CONTAINER_MDLL_remove (PR, prd->pr_head, prd->pr_tail, bi); GNUNET_free (bi); } plan_count--; GNUNET_free (rp); } GNUNET_CONTAINER_heap_destroy (pp->priority_heap); while (NULL != (rp = GNUNET_CONTAINER_heap_remove_root (pp->delay_heap))) { GNUNET_break (GNUNET_YES == GNUNET_CONTAINER_multihashmap_remove (pp->plan_map, get_rp_key (rp), rp)); while (NULL != (bi = rp->pe_head)) { prd = GSF_pending_request_get_data_ (bi->pr); GNUNET_CONTAINER_MDLL_remove (PE, rp->pe_head, rp->pe_tail, bi); GNUNET_CONTAINER_MDLL_remove (PR, prd->pr_head, prd->pr_tail, bi); GNUNET_free (bi); } plan_count--; GNUNET_free (rp); } GNUNET_STATISTICS_set (GSF_stats, gettext_noop ("# query plan entries"), plan_count, GNUNET_NO); GNUNET_CONTAINER_heap_destroy (pp->delay_heap); GNUNET_CONTAINER_multihashmap_destroy (pp->plan_map); GNUNET_free (pp); } /** * Get the last transmission attempt time for the request plan list * referenced by @a pr_head, that was sent to @a sender * * @param pr_head request plan reference list to check. * @param sender the peer that we've sent the request to. * @param result the timestamp to fill, set to #GNUNET_TIME_UNIT_FOREVER_ABS if never transmitted * @return #GNUNET_YES if @a result was changed, #GNUNET_NO otherwise. */ int GSF_request_plan_reference_get_last_transmission_ (struct GSF_PendingRequestPlanBijection *pr_head, struct GSF_ConnectedPeer *sender, struct GNUNET_TIME_Absolute *result) { struct GSF_PendingRequestPlanBijection *bi; for (bi = pr_head; NULL != bi; bi = bi->next_PR) { if (bi->rp->pp->cp == sender) { if (0 == bi->rp->last_transmission.abs_value_us) *result = GNUNET_TIME_UNIT_FOREVER_ABS; else *result = bi->rp->last_transmission; return GNUNET_YES; } } return GNUNET_NO; } /** * Notify the plan about a request being done; destroy all entries * associated with this request. * * @param pr request that is done */ void GSF_plan_notify_request_done_ (struct GSF_PendingRequest *pr) { struct GSF_RequestPlan *rp; struct GSF_PendingRequestData *prd; struct GSF_PendingRequestPlanBijection *bi; prd = GSF_pending_request_get_data_ (pr); while (NULL != (bi = prd->pr_head)) { rp = bi->rp; GNUNET_CONTAINER_MDLL_remove (PR, prd->pr_head, prd->pr_tail, bi); GNUNET_CONTAINER_MDLL_remove (PE, rp->pe_head, rp->pe_tail, bi); GNUNET_assert (bi->pr == pr); if (NULL == rp->pe_head) { GNUNET_CONTAINER_heap_remove_node (rp->hn); plan_count--; GNUNET_break (GNUNET_YES == GNUNET_CONTAINER_multihashmap_remove (rp->pp->plan_map, &prd->query, rp)); GNUNET_free (rp); } GNUNET_free (bi); } GNUNET_STATISTICS_set (GSF_stats, gettext_noop ("# query plan entries"), plan_count, GNUNET_NO); } /** * Initialize plan subsystem. */ void GSF_plan_init () { plans = GNUNET_CONTAINER_multipeermap_create (256, GNUNET_YES); } /** * Shutdown plan subsystem. */ void GSF_plan_done () { GNUNET_assert (0 == GNUNET_CONTAINER_multipeermap_size (plans)); GNUNET_CONTAINER_multipeermap_destroy (plans); } /* end of gnunet-service-fs_pe.h */