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22 * @file fs/gnunet-service-fs_push.c
23 * @brief API to push content from our datastore to other peers
24 * ('anonymous'-content P2P migration)
25 * @author Christian Grothoff
28 #include "gnunet-service-fs.h"
29 #include "gnunet-service-fs_cp.h"
30 #include "gnunet-service-fs_indexing.h"
31 #include "gnunet-service-fs_push.h"
35 * Maximum number of blocks we keep in memory for migration.
37 #define MAX_MIGRATION_QUEUE 8
40 * Blocks are at most migrated to this number of peers
41 * plus one, each time they are fetched from the database.
43 #define MIGRATION_LIST_SIZE 2
46 * How long must content remain valid for us to consider it for migration?
47 * If content will expire too soon, there is clearly no point in pushing
48 * it to other peers. This value gives the threshold for migration. Note
49 * that if this value is increased, the migration testcase may need to be
50 * adjusted as well (especially the CONTENT_LIFETIME in fs_test_lib.c).
52 #define MIN_MIGRATION_CONTENT_LIFETIME GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, 30)
56 * Block that is ready for migration to other peers. Actual data is at the end of the block.
58 struct MigrationReadyBlock
62 * This is a doubly-linked list.
64 struct MigrationReadyBlock *next;
67 * This is a doubly-linked list.
69 struct MigrationReadyBlock *prev;
72 * Query for the block.
74 struct GNUNET_HashCode query;
77 * When does this block expire?
79 struct GNUNET_TIME_Absolute expiration;
82 * Peers we already forwarded this
83 * block to. Zero for empty entries.
85 GNUNET_PEER_Id target_list[MIGRATION_LIST_SIZE];
93 * Number of targets already used.
95 unsigned int used_targets;
100 enum GNUNET_BLOCK_Type type;
105 * Information about a peer waiting for migratable data.
107 struct MigrationReadyPeer
110 * This is a doubly-linked list.
112 struct MigrationReadyPeer *next;
115 * This is a doubly-linked list.
117 struct MigrationReadyPeer *prev;
122 struct GSF_ConnectedPeer *peer;
125 * Envelope of the currently pushed message.
127 struct GNUNET_MQ_Envelope *env;
132 * Head of linked list of blocks that can be migrated.
134 static struct MigrationReadyBlock *mig_head;
137 * Tail of linked list of blocks that can be migrated.
139 static struct MigrationReadyBlock *mig_tail;
142 * Head of linked list of peers.
144 static struct MigrationReadyPeer *peer_head;
147 * Tail of linked list of peers.
149 static struct MigrationReadyPeer *peer_tail;
152 * Request to datastore for migration (or NULL).
154 static struct GNUNET_DATASTORE_QueueEntry *mig_qe;
157 * ID of task that collects blocks for migration.
159 static struct GNUNET_SCHEDULER_Task *mig_task;
162 * What is the maximum frequency at which we are allowed to
163 * poll the datastore for migration content?
165 static struct GNUNET_TIME_Relative min_migration_delay;
168 * Size of the doubly-linked list of migration blocks.
170 static unsigned int mig_size;
173 * Is this module enabled?
178 * Did we find anything in the datastore?
180 static int value_found;
184 * Delete the given migration block.
186 * @param mb block to delete
189 delete_migration_block (struct MigrationReadyBlock *mb)
191 GNUNET_CONTAINER_DLL_remove (mig_head,
194 GNUNET_PEER_decrement_rcs (mb->target_list,
195 MIGRATION_LIST_SIZE);
202 * Find content for migration to this peer.
204 * @param cls a `struct MigrationReadyPeer *`
207 find_content (void *cls);
211 * Send the given block to the given peer.
213 * @param peer target peer
214 * @param block the block
215 * @return #GNUNET_YES if the block was deleted (!)
218 transmit_content (struct MigrationReadyPeer *mrp,
219 struct MigrationReadyBlock *block)
221 struct PutMessage *msg;
223 struct GSF_PeerPerformanceData *ppd;
226 ppd = GSF_get_peer_performance_data_ (mrp->peer);
227 mrp->env = GNUNET_MQ_msg_extra (msg,
229 GNUNET_MESSAGE_TYPE_FS_PUT);
230 msg->type = htonl (block->type);
231 msg->expiration = GNUNET_TIME_absolute_hton (block->expiration);
232 GNUNET_memcpy (&msg[1],
235 for (i = 0; i < MIGRATION_LIST_SIZE; i++)
237 if (block->target_list[i] == 0)
239 block->target_list[i] = ppd->pid;
240 GNUNET_PEER_change_rc (block->target_list[i],
245 if (MIGRATION_LIST_SIZE == i)
247 delete_migration_block (block);
254 GNUNET_MQ_notify_sent (mrp->env,
257 GSF_peer_transmit_ (mrp->peer,
266 * Count the number of peers this block has
267 * already been forwarded to.
269 * @param block the block
270 * @return number of times block was forwarded
273 count_targets (struct MigrationReadyBlock *block)
277 for (i = 0; i < MIGRATION_LIST_SIZE; i++)
278 if (block->target_list[i] == 0)
285 * Check if sending this block to this peer would
288 * @param mrp target peer
289 * @param block the block
290 * @return score (>= 0: feasible, negative: infeasible)
293 score_content (struct MigrationReadyPeer *mrp,
294 struct MigrationReadyBlock *block)
297 struct GSF_PeerPerformanceData *ppd;
298 struct GNUNET_PeerIdentity id;
299 struct GNUNET_HashCode hc;
302 ppd = GSF_get_peer_performance_data_ (mrp->peer);
303 for (i = 0; i < MIGRATION_LIST_SIZE; i++)
304 if (block->target_list[i] == ppd->pid)
306 GNUNET_assert (0 != ppd->pid);
307 GNUNET_PEER_resolve (ppd->pid,
309 GNUNET_CRYPTO_hash (&id,
310 sizeof (struct GNUNET_PeerIdentity),
312 dist = GNUNET_CRYPTO_hash_distance_u32 (&block->query,
314 /* closer distance, higher score: */
315 return UINT32_MAX - dist;
320 * If the migration task is not currently running, consider
321 * (re)scheduling it with the appropriate delay.
324 consider_gathering (void);
328 * Find content for migration to this peer.
330 * @param cls peer to find content for
333 find_content (void *cls)
335 struct MigrationReadyPeer *mrp = cls;
336 struct MigrationReadyBlock *pos;
339 struct MigrationReadyBlock *best;
347 score = score_content (mrp, pos);
348 if (score > best_score)
357 if (mig_size < MAX_MIGRATION_QUEUE)
359 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
360 "No content found for pushing, waiting for queue to fill\n");
361 return; /* will fill up eventually... */
363 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
364 "No suitable content found, purging content from full queue\n");
365 /* failed to find migration target AND
366 * queue is full, purge most-forwarded
367 * block from queue to make room for more */
371 score = count_targets (pos);
372 if (score >= best_score)
379 GNUNET_assert (NULL != best);
380 delete_migration_block (best);
381 consider_gathering ();
384 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
385 "Preparing to push best content to peer\n");
386 transmit_content (mrp,
392 * Task that is run periodically to obtain blocks for content
398 gather_migration_blocks (void *cls);
402 * If the migration task is not currently running, consider
403 * (re)scheduling it with the appropriate delay.
406 consider_gathering ()
408 struct GNUNET_TIME_Relative delay;
414 if (NULL != mig_task)
416 if (mig_size >= MAX_MIGRATION_QUEUE)
418 delay = GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS,
420 delay = GNUNET_TIME_relative_divide (delay,
421 MAX_MIGRATION_QUEUE);
422 delay = GNUNET_TIME_relative_max (delay,
423 min_migration_delay);
424 if (GNUNET_NO == value_found)
426 /* wait at least 5s if the datastore is empty */
427 delay = GNUNET_TIME_relative_max (delay,
428 GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS,
431 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
432 "Scheduling gathering task (queue size: %u)\n",
434 mig_task = GNUNET_SCHEDULER_add_delayed (delay,
435 &gather_migration_blocks,
441 * Process content offered for migration.
444 * @param key key for the content
445 * @param size number of bytes in data
446 * @param data content stored
447 * @param type type of the content
448 * @param priority priority of the content
449 * @param anonymity anonymity-level for the content
450 * @param expiration expiration time for the content
451 * @param uid unique identifier for the datum;
452 * maybe 0 if no unique identifier is available
455 process_migration_content (void *cls,
456 const struct GNUNET_HashCode *key,
459 enum GNUNET_BLOCK_Type type,
462 struct GNUNET_TIME_Absolute expiration,
465 struct MigrationReadyBlock *mb;
466 struct MigrationReadyPeer *pos;
471 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
472 "No content found for migration...\n");
473 consider_gathering ();
476 value_found = GNUNET_YES;
477 if (GNUNET_TIME_absolute_get_remaining (expiration).rel_value_us <
478 MIN_MIGRATION_CONTENT_LIFETIME.rel_value_us)
480 /* content will expire soon, don't bother */
481 consider_gathering ();
484 if (type == GNUNET_BLOCK_TYPE_FS_ONDEMAND)
487 GNUNET_FS_handle_on_demand_block (key,
495 &process_migration_content, NULL))
496 consider_gathering ();
499 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
500 "Retrieved block `%s' of type %u for migration (queue size: %u/%u)\n",
503 MAX_MIGRATION_QUEUE);
504 mb = GNUNET_malloc (sizeof (struct MigrationReadyBlock) + size);
506 mb->expiration = expiration;
509 GNUNET_memcpy (&mb[1], data, size);
510 GNUNET_CONTAINER_DLL_insert_after (mig_head,
515 for (pos = peer_head; NULL != pos; pos = pos->next)
517 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
518 "Preparing to push best content to peer %s\n",
519 GNUNET_i2s (GSF_connected_peer_get_identity2_(pos->peer)));
520 if (GNUNET_YES == transmit_content (pos,
522 break; /* 'mb' was freed! */
524 consider_gathering ();
529 * Task that is run periodically to obtain blocks for content
535 gather_migration_blocks (void *cls)
538 if (mig_size >= MAX_MIGRATION_QUEUE)
542 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
543 "Asking datastore for content for replication (queue size: %u)\n",
545 value_found = GNUNET_NO;
546 mig_qe = GNUNET_DATASTORE_get_for_replication (GSF_dsh,
549 &process_migration_content,
552 consider_gathering ();
557 * A peer connected to us. Start pushing content
560 * @param peer handle for the peer that connected
563 GSF_push_start_ (struct GSF_ConnectedPeer *peer)
565 struct MigrationReadyPeer *mrp;
567 if (GNUNET_YES != enabled)
569 for (mrp = peer_head; NULL != mrp; mrp = mrp->next)
570 if (mrp->peer == peer)
574 /* same peer added twice, must not happen */
579 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
580 "Adding peer %s to list for pushing\n",
581 GNUNET_i2s (GSF_connected_peer_get_identity2_(peer)));
583 mrp = GNUNET_new (struct MigrationReadyPeer);
586 GNUNET_CONTAINER_DLL_insert (peer_head,
593 * A peer disconnected from us. Stop pushing content
596 * @param peer handle for the peer that disconnected
599 GSF_push_stop_ (struct GSF_ConnectedPeer *peer)
601 struct MigrationReadyPeer *pos;
603 for (pos = peer_head; NULL != pos; pos = pos->next)
604 if (pos->peer == peer)
608 if (NULL != pos->env)
609 GNUNET_MQ_send_cancel (pos->env);
610 GNUNET_CONTAINER_DLL_remove (peer_head,
624 GNUNET_CONFIGURATION_get_value_yesno (GSF_cfg,
627 if (GNUNET_YES != enabled)
631 GNUNET_CONFIGURATION_get_value_time (GSF_cfg,
633 "MIN_MIGRATION_DELAY",
634 &min_migration_delay))
636 GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_WARNING,
638 "MIN_MIGRATION_DELAY",
639 _("time required, content pushing disabled"));
642 consider_gathering ();
647 * Shutdown the module.
652 if (NULL != mig_task)
654 GNUNET_SCHEDULER_cancel (mig_task);
659 GNUNET_DATASTORE_cancel (mig_qe);
662 while (NULL != mig_head)
663 delete_migration_block (mig_head);
664 GNUNET_assert (0 == mig_size);
667 /* end of gnunet-service-fs_push.c */