/* This file is part of GNUnet. (C) 2011 Christian Grothoff (and other contributing authors) GNUnet is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, 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 General Public License for more details. You should have received a copy of the GNU General Public License along with GNUnet; see the file COPYING. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ /** * @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" /** * List of GSF_PendingRequests this request plan * participates with. */ struct PendingRequestList; /** * Transmission plan for a peer. */ struct PeerPlan; /** * DLL of request plans a particular pending request is * involved with. */ struct GSF_RequestPlanReference { /** * This is a doubly-linked list. */ struct GSF_RequestPlanReference *next; /** * This is a doubly-linked list. */ struct GSF_RequestPlanReference *prev; /** * Associated request plan. */ struct GSF_RequestPlan *rp; /** * Corresponding PendingRequestList. */ struct PendingRequestList *prl; }; /** * List of GSF_PendingRequests this request plan * participates with. */ struct PendingRequestList { /** * This is a doubly-linked list. */ struct PendingRequestList *next; /** * This is a doubly-linked list. */ struct PendingRequestList *prev; /** * Associated pending request. */ struct GSF_PendingRequest *pr; /** * Corresponding GSF_RequestPlanReference. */ struct GSF_RequestPlanReference *rpr; }; /** * 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. */ struct PendingRequestList *prl_head; /** * Tail of list of associated pending requests. */ struct PendingRequestList *prl_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 priority_heap or delay_heap * should be in the plan map. Note that it IS possible for the plan map to have * multiple entries for the same query. */ struct GNUNET_CONTAINER_MultiHashMap *plan_map; /** * Current transmission request handle. */ struct GSF_PeerTransmitHandle *pth; /** * Peer for which this is the plan. */ struct GSF_ConnectedPeer *cp; /** * Current task for executing the plan. */ GNUNET_SCHEDULER_TaskIdentifier task; }; /** * Hash map from peer identities to PeerPlans. */ static struct GNUNET_CONTAINER_MultiHashMap *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. * * @param rp a request plan * @return the associated query */ static const GNUNET_HashCode * get_rp_key (struct GSF_RequestPlan *rp) { return &GSF_pending_request_get_data_ (rp->prl_head->pr)->query; } /** * Figure out when and how to transmit to the given peer. * * @param cls the 'struct GSF_ConnectedPeer' for transmission * @param tc scheduler context */ static void schedule_peer_transmission (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc); /** * 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->prl_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 = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK, delay.rel_value + 1); /* Add 0.01 to avg_delay to avoid division-by-zero later */ avg_delay = (((avg_delay * (N-1.0)) + delay.rel_value) / 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 / avg_delay)) / M_PI_4; /* Note: usage of 'round' and 'atan' requires -lm */ if (rp->transmission_counter != 0) delay.rel_value += TTL_DECREMENT; GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Considering (re)transmission number %u in %llu ms\n", (unsigned int) rp->transmission_counter, (unsigned long long) delay.rel_value); rp->earliest_transmission = GNUNET_TIME_relative_to_absolute (delay); #if DEBUG_FS GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Earliest (re)transmission for `%s' in %us\n", GNUNET_h2s (&prd->query), rp->transmission_counter); #endif GNUNET_assert (rp->hn == NULL); if (GNUNET_TIME_absolute_get_remaining (rp->earliest_transmission).rel_value == 0) 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); GNUNET_assert (GNUNET_YES == GNUNET_CONTAINER_multihashmap_contains_value (pp->plan_map, get_rp_key (rp), rp)); if (GNUNET_SCHEDULER_NO_TASK != pp->task) GNUNET_SCHEDULER_cancel (pp->task); pp->task = GNUNET_SCHEDULER_add_now (&schedule_peer_transmission, pp); #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 PendingRequestList *prl; prl = rp->prl_head; ret = prl->pr; prl = prl->next; while (NULL != prl) { if (GSF_pending_request_get_data_ (prl->pr)->ttl.abs_value > GSF_pending_request_get_data_ (ret)->ttl.abs_value) ret = prl->pr; prl = prl->next; } return ret; } /** * Function called to get a message for transmission. * * @param cls closure * @param buf_size number of bytes available in buf * @param buf where to copy the message, NULL on error (peer disconnect) * @return number of bytes copied to 'buf', can be 0 (without indicating an error) */ static size_t transmit_message_callback (void *cls, size_t buf_size, void *buf) { struct PeerPlan *pp = cls; struct GSF_RequestPlan *rp; size_t msize; pp->pth = NULL; if (NULL == buf) { /* failed, try again... */ pp->task = GNUNET_SCHEDULER_add_now (&schedule_peer_transmission, pp); GNUNET_STATISTICS_update (GSF_stats, gettext_noop ("# transmission failed (core has no bandwidth)"), 1, GNUNET_NO); return 0; } rp = GNUNET_CONTAINER_heap_peek (pp->priority_heap); if (NULL == rp) { pp->task = GNUNET_SCHEDULER_add_now (&schedule_peer_transmission, pp); return 0; } msize = GSF_pending_request_get_message_ (get_latest (rp), buf_size, buf); if (msize > buf_size) { /* buffer to small (message changed), try again */ pp->task = GNUNET_SCHEDULER_add_now (&schedule_peer_transmission, pp); return 0; } /* remove from root, add again elsewhere... */ GNUNET_assert (rp == GNUNET_CONTAINER_heap_remove_root (pp->priority_heap)); rp->hn = NULL; rp->last_transmission = GNUNET_TIME_absolute_get (); rp->transmission_counter++; total_delay++; #if DEBUG_FS GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Executing plan %p executed %u times, planning retransmission\n", rp, rp->transmission_counter); #endif plan (pp, rp); GNUNET_STATISTICS_update (GSF_stats, gettext_noop ("# query messages sent to other peers"), 1, GNUNET_NO); return msize; } /** * Figure out when and how to transmit to the given peer. * * @param cls the 'struct PeerPlan' * @param tc scheduler context */ static void schedule_peer_transmission (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) { struct PeerPlan *pp = cls; struct GSF_RequestPlan *rp; size_t msize; struct GNUNET_TIME_Relative delay; pp->task = GNUNET_SCHEDULER_NO_TASK; if (pp->pth != NULL) { GSF_peer_transmit_cancel_ (pp->pth); pp->pth = NULL; } /* move ready requests to priority queue */ while ((NULL != (rp = GNUNET_CONTAINER_heap_peek (pp->delay_heap))) && (GNUNET_TIME_absolute_get_remaining (rp->earliest_transmission).rel_value == 0)) { 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) { #if DEBUG_FS GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "No active requests for plan %p.\n", pp); #endif return; /* both queues empty */ } delay = GNUNET_TIME_absolute_get_remaining (rp->earliest_transmission); #if DEBUG_FS GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Sleeping for %llu ms before retrying requests on plan %p.\n", (unsigned long long) delay.rel_value, pp); #endif GNUNET_STATISTICS_set (GSF_stats, gettext_noop ("# delay heap timeout"), delay.rel_value, GNUNET_NO); pp->task = GNUNET_SCHEDULER_add_delayed (delay, &schedule_peer_transmission, pp); return; } GNUNET_STATISTICS_update (GSF_stats, gettext_noop ("# query plans executed"), 1, GNUNET_NO); /* process from priority heap */ rp = GNUNET_CONTAINER_heap_peek (pp->priority_heap); #if DEBUG_FS > 1 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Executing query plan %p\n", rp); #endif GNUNET_assert (NULL != rp); msize = GSF_pending_request_get_message_ (get_latest (rp), 0, NULL); pp->pth = GSF_peer_transmit_ (pp->cp, GNUNET_YES, rp->priority, GNUNET_TIME_UNIT_FOREVER_REL, msize, &transmit_message_callback, pp); GNUNET_assert (NULL != pp->pth); } /** * Closure for 'merge_pr'. */ struct MergeContext { struct GSF_PendingRequest *pr; 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 GNUNET_HashCode * query, void *element) { struct MergeContext *mpr = cls; struct GSF_RequestPlan *rp = element; struct GSF_PendingRequestData *prd; struct GSF_RequestPlanReference *rpr; struct PendingRequestList *prl; struct GSF_PendingRequest *latest; if (GNUNET_OK != GSF_pending_request_is_compatible_ (mpr->pr, rp->prl_head->pr)) return GNUNET_YES; /* merge new request with existing request plan */ rpr = GNUNET_malloc (sizeof (struct GSF_RequestPlanReference)); prl = GNUNET_malloc (sizeof (struct PendingRequestList)); rpr->rp = rp; rpr->prl = prl; prl->rpr = rpr; prl->pr = mpr->pr; prd = GSF_pending_request_get_data_ (mpr->pr); GNUNET_CONTAINER_DLL_insert (prd->rpr_head, prd->rpr_tail, rpr); GNUNET_CONTAINER_DLL_insert (rp->prl_head, rp->prl_tail, prl); mpr->merged = GNUNET_YES; GNUNET_STATISTICS_update (GSF_stats, gettext_noop ("# requests merged"), 1, GNUNET_NO); latest = get_latest (rp); if (GSF_pending_request_get_data_ (latest)->ttl.abs_value < prd->ttl.abs_value) { GNUNET_STATISTICS_update (GSF_stats, gettext_noop ("# requests refreshed"), 1, GNUNET_NO); 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) { struct GNUNET_PeerIdentity id; struct PeerPlan *pp; struct GSF_PendingRequestData *prd; struct GSF_RequestPlan *rp; struct GSF_RequestPlanReference *rpr; struct PendingRequestList *prl; struct MergeContext mpc; GNUNET_assert (NULL != cp); GSF_connected_peer_get_identity_ (cp, &id); pp = GNUNET_CONTAINER_multihashmap_get (plans, &id.hashPubKey); if (NULL == pp) { pp = GNUNET_malloc (sizeof (struct PeerPlan)); pp->plan_map = GNUNET_CONTAINER_multihashmap_create (128); 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_CONTAINER_multihashmap_put (plans, &id.hashPubKey, pp, GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY); } mpc.merged = GNUNET_NO; mpc.pr = pr; GNUNET_CONTAINER_multihashmap_get_multiple (pp->plan_map, &GSF_pending_request_get_data_ (pr)->query, &merge_pr, &mpc); if (mpc.merged != GNUNET_NO) return; GNUNET_CONTAINER_multihashmap_get_multiple (pp->plan_map, &GSF_pending_request_get_data_ (pr)->query, &merge_pr, &mpc); if (mpc.merged != GNUNET_NO) return; plan_count++; GNUNET_STATISTICS_update (GSF_stats, gettext_noop ("# query plan entries"), 1, GNUNET_NO); prd = GSF_pending_request_get_data_ (pr); #if DEBUG_FS GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Planning transmission of query `%s' to peer `%s'\n", GNUNET_h2s (&prd->query), GNUNET_i2s (&id)); #endif rp = GNUNET_malloc (sizeof (struct GSF_RequestPlan)); rpr = GNUNET_malloc (sizeof (struct GSF_RequestPlanReference)); prl = GNUNET_malloc (sizeof (struct PendingRequestList)); rpr->rp = rp; rpr->prl = prl; prl->rpr = rpr; prl->pr = pr; GNUNET_CONTAINER_DLL_insert (prd->rpr_head, prd->rpr_tail, rpr); GNUNET_CONTAINER_DLL_insert (rp->prl_head, rp->prl_tail, prl); 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) { struct GNUNET_PeerIdentity id; struct PeerPlan *pp; struct GSF_RequestPlan *rp; struct GSF_PendingRequestData *prd; struct PendingRequestList *prl; GSF_connected_peer_get_identity_ (cp, &id); pp = GNUNET_CONTAINER_multihashmap_get (plans, &id.hashPubKey); if (NULL == pp) return; /* nothing was ever planned for this peer */ GNUNET_assert (GNUNET_YES == GNUNET_CONTAINER_multihashmap_remove (plans, &id.hashPubKey, pp)); if (NULL != pp->pth) GSF_peer_transmit_cancel_ (pp->pth); if (GNUNET_SCHEDULER_NO_TASK != pp->task) { GNUNET_SCHEDULER_cancel (pp->task); pp->task = GNUNET_SCHEDULER_NO_TASK; } 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 != (prl = rp->prl_head)) { GNUNET_CONTAINER_DLL_remove (rp->prl_head, rp->prl_tail, prl); prd = GSF_pending_request_get_data_ (prl->pr); GNUNET_CONTAINER_DLL_remove (prd->rpr_head, prd->rpr_tail, prl->rpr); GNUNET_free (prl->rpr); GNUNET_free (prl); } 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 != (prl = rp->prl_head)) { GNUNET_CONTAINER_DLL_remove (rp->prl_head, rp->prl_tail, prl); prd = GSF_pending_request_get_data_ (prl->pr); GNUNET_CONTAINER_DLL_remove (prd->rpr_head, prd->rpr_tail, prl->rpr); GNUNET_free (prl->rpr); GNUNET_free (prl); } 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); } /** * 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_RequestPlanReference *rpr; prd = GSF_pending_request_get_data_ (pr); while (NULL != (rpr = prd->rpr_head)) { GNUNET_CONTAINER_DLL_remove (prd->rpr_head, prd->rpr_tail, rpr); rp = rpr->rp; GNUNET_CONTAINER_DLL_remove (rp->prl_head, rp->prl_tail, rpr->prl); if (NULL == rp->prl_head) { GNUNET_CONTAINER_heap_remove_node (rp->hn); plan_count--; GNUNET_break (GNUNET_YES == GNUNET_CONTAINER_multihashmap_remove (rp->pp->plan_map, &GSF_pending_request_get_data_ (rpr->prl->pr)->query, rp)); GNUNET_free (rp); } GNUNET_free (rpr->prl); GNUNET_free (rpr); } GNUNET_STATISTICS_set (GSF_stats, gettext_noop ("# query plan entries"), plan_count, GNUNET_NO); } /** * Initialize plan subsystem. */ void GSF_plan_init () { plans = GNUNET_CONTAINER_multihashmap_create (256); } /** * Shutdown plan subsystem. */ void GSF_plan_done () { GNUNET_assert (0 == GNUNET_CONTAINER_multihashmap_size (plans)); GNUNET_CONTAINER_multihashmap_destroy (plans); } /* end of gnunet-service-fs_pe.h */