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_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
108 struct MigrationReadyPeer
111 * This is a doubly-linked list.
113 struct MigrationReadyPeer *next;
116 * This is a doubly-linked list.
118 struct MigrationReadyPeer *prev;
123 struct GSF_ConnectedPeer *peer;
126 * Handle for current transmission request,
129 struct GSF_PeerTransmitHandle *th;
132 * Message we are trying to push right now (or NULL)
134 struct PutMessage *msg;
139 * Head of linked list of blocks that can be migrated.
141 static struct MigrationReadyBlock *mig_head;
144 * Tail of linked list of blocks that can be migrated.
146 static struct MigrationReadyBlock *mig_tail;
149 * Head of linked list of peers.
151 static struct MigrationReadyPeer *peer_head;
154 * Tail of linked list of peers.
156 static struct MigrationReadyPeer *peer_tail;
159 * Request to datastore for migration (or NULL).
161 static struct GNUNET_DATASTORE_QueueEntry *mig_qe;
164 * ID of task that collects blocks for migration.
166 static GNUNET_SCHEDULER_TaskIdentifier mig_task;
169 * What is the maximum frequency at which we are allowed to
170 * poll the datastore for migration content?
172 static struct GNUNET_TIME_Relative min_migration_delay;
175 * Size of the doubly-linked list of migration blocks.
177 static unsigned int mig_size;
180 * Is this module enabled?
186 * Delete the given migration block.
188 * @param mb block to delete
191 delete_migration_block (struct MigrationReadyBlock *mb)
193 GNUNET_CONTAINER_DLL_remove (mig_head, mig_tail, mb);
194 GNUNET_PEER_decrement_rcs (mb->target_list, MIGRATION_LIST_SIZE);
201 * Find content for migration to this peer.
204 find_content (struct MigrationReadyPeer *mrp);
208 * Transmit the message currently scheduled for
211 * @param cls the 'struct MigrationReadyPeer'
212 * @param buf_size number of bytes available in buf
213 * @param buf where to copy the message, NULL on error (peer disconnect)
214 * @return number of bytes copied to 'buf', can be 0 (without indicating an error)
217 transmit_message (void *cls, size_t buf_size, void *buf)
219 struct MigrationReadyPeer *peer = cls;
220 struct PutMessage *msg;
228 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
229 "Failed to migrate content to another peer (disconnect)\n");
233 msize = ntohs (msg->header.size);
234 GNUNET_assert (msize <= buf_size);
235 memcpy (buf, msg, msize);
237 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Pushing %u bytes to another peer\n",
245 * Send the given block to the given peer.
247 * @param peer target peer
248 * @param block the block
249 * @return GNUNET_YES if the block was deleted (!)
252 transmit_content (struct MigrationReadyPeer *peer,
253 struct MigrationReadyBlock *block)
256 struct PutMessage *msg;
258 struct GSF_PeerPerformanceData *ppd;
261 ppd = GSF_get_peer_performance_data_ (peer->peer);
262 GNUNET_assert (NULL == peer->th);
263 msize = sizeof (struct PutMessage) + block->size;
264 msg = GNUNET_malloc (msize);
265 msg->header.type = htons (GNUNET_MESSAGE_TYPE_FS_PUT);
266 msg->header.size = htons (msize);
267 msg->type = htonl (block->type);
268 msg->expiration = GNUNET_TIME_absolute_hton (block->expiration);
269 memcpy (&msg[1], &block[1], block->size);
271 for (i = 0; i < MIGRATION_LIST_SIZE; i++)
273 if (block->target_list[i] == 0)
275 block->target_list[i] = ppd->pid;
276 GNUNET_PEER_change_rc (block->target_list[i], 1);
280 if (MIGRATION_LIST_SIZE == i)
282 delete_migration_block (block);
289 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
290 "Asking for transmission of %u bytes for migration\n", msize);
291 peer->th = GSF_peer_transmit_ (peer->peer, GNUNET_NO, 0 /* priority */ ,
292 GNUNET_TIME_UNIT_FOREVER_REL, msize,
293 &transmit_message, peer);
299 * Count the number of peers this block has
300 * already been forwarded to.
302 * @param block the block
303 * @return number of times block was forwarded
306 count_targets (struct MigrationReadyBlock *block)
310 for (i = 0; i < MIGRATION_LIST_SIZE; i++)
311 if (block->target_list[i] == 0)
318 * Check if sending this block to this peer would
321 * @param peer target peer
322 * @param block the block
323 * @return score (>= 0: feasible, negative: infeasible)
326 score_content (struct MigrationReadyPeer *peer,
327 struct MigrationReadyBlock *block)
330 struct GSF_PeerPerformanceData *ppd;
331 struct GNUNET_PeerIdentity id;
332 struct GNUNET_HashCode hc;
335 ppd = GSF_get_peer_performance_data_ (peer->peer);
336 for (i = 0; i < MIGRATION_LIST_SIZE; i++)
337 if (block->target_list[i] == ppd->pid)
339 GNUNET_assert (0 != ppd->pid);
340 GNUNET_PEER_resolve (ppd->pid, &id);
341 GNUNET_CRYPTO_hash (&id, sizeof (struct GNUNET_PeerIdentity), &hc);
342 dist = GNUNET_CRYPTO_hash_distance_u32 (&block->query, &hc);
343 /* closer distance, higher score: */
344 return UINT32_MAX - dist;
349 * If the migration task is not currently running, consider
350 * (re)scheduling it with the appropriate delay.
353 consider_gathering (void);
357 * Find content for migration to this peer.
359 * @param mrp peer to find content for
362 find_content (struct MigrationReadyPeer *mrp)
364 struct MigrationReadyBlock *pos;
367 struct MigrationReadyBlock *best;
369 GNUNET_assert (NULL == mrp->th);
375 score = score_content (mrp, pos);
376 if (score > best_score)
385 if (mig_size < MAX_MIGRATION_QUEUE)
387 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
388 "No content found for pushing, waiting for queue to fill\n");
389 return; /* will fill up eventually... */
391 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
392 "No suitable content found, purging content from full queue\n");
393 /* failed to find migration target AND
394 * queue is full, purge most-forwarded
395 * block from queue to make room for more */
399 score = count_targets (pos);
400 if (score >= best_score)
407 GNUNET_assert (NULL != best);
408 delete_migration_block (best);
409 consider_gathering ();
412 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
413 "Preparing to push best content to peer\n");
414 transmit_content (mrp, best);
419 * Task that is run periodically to obtain blocks for content
423 * @param tc scheduler context (also unused)
426 gather_migration_blocks (void *cls,
427 const struct GNUNET_SCHEDULER_TaskContext *tc);
431 * If the migration task is not currently running, consider
432 * (re)scheduling it with the appropriate delay.
435 consider_gathering ()
437 struct GNUNET_TIME_Relative delay;
443 if (mig_task != GNUNET_SCHEDULER_NO_TASK)
445 if (mig_size >= MAX_MIGRATION_QUEUE)
447 delay = GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, mig_size);
448 delay = GNUNET_TIME_relative_divide (delay, MAX_MIGRATION_QUEUE);
449 delay = GNUNET_TIME_relative_max (delay, min_migration_delay);
450 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
451 "Scheduling gathering task (queue size: %u)\n", mig_size);
453 GNUNET_SCHEDULER_add_delayed (delay, &gather_migration_blocks, NULL);
458 * Process content offered for migration.
461 * @param key key for the content
462 * @param size number of bytes in data
463 * @param data content stored
464 * @param type type of the content
465 * @param priority priority of the content
466 * @param anonymity anonymity-level for the content
467 * @param expiration expiration time for the content
468 * @param uid unique identifier for the datum;
469 * maybe 0 if no unique identifier is available
472 process_migration_content (void *cls, const struct GNUNET_HashCode * key, size_t size,
473 const void *data, enum GNUNET_BLOCK_Type type,
474 uint32_t priority, uint32_t anonymity,
475 struct GNUNET_TIME_Absolute expiration, uint64_t uid)
477 struct MigrationReadyBlock *mb;
478 struct MigrationReadyPeer *pos;
483 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "No content found for migration...\n");
484 consider_gathering ();
487 if (GNUNET_TIME_absolute_get_remaining (expiration).rel_value_us <
488 MIN_MIGRATION_CONTENT_LIFETIME.rel_value_us)
490 /* content will expire soon, don't bother */
491 consider_gathering ();
494 if (type == GNUNET_BLOCK_TYPE_FS_ONDEMAND)
497 GNUNET_FS_handle_on_demand_block (key, size, data, type, priority,
498 anonymity, expiration, uid,
499 &process_migration_content, NULL))
500 consider_gathering ();
503 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
504 "Retrieved block `%s' of type %u for migration (queue size: %u/%u)\n",
505 GNUNET_h2s (key), type, mig_size + 1, MAX_MIGRATION_QUEUE);
506 mb = GNUNET_malloc (sizeof (struct MigrationReadyBlock) + size);
508 mb->expiration = expiration;
511 memcpy (&mb[1], data, size);
512 GNUNET_CONTAINER_DLL_insert_after (mig_head, mig_tail, mig_tail, mb);
519 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
520 "Preparing to push best content to peer\n");
521 if (GNUNET_YES == transmit_content (pos, mb))
522 break; /* 'mb' was freed! */
526 consider_gathering ();
531 * Task that is run periodically to obtain blocks for content
535 * @param tc scheduler context (also unused)
538 gather_migration_blocks (void *cls,
539 const struct GNUNET_SCHEDULER_TaskContext *tc)
541 mig_task = GNUNET_SCHEDULER_NO_TASK;
542 if (mig_size >= MAX_MIGRATION_QUEUE)
546 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
547 "Asking datastore for content for replication (queue size: %u)\n",
550 GNUNET_DATASTORE_get_for_replication (GSF_dsh, 0, UINT_MAX,
551 GNUNET_TIME_UNIT_FOREVER_REL,
552 &process_migration_content, NULL);
554 consider_gathering ();
560 * A peer connected to us. Start pushing content
563 * @param peer handle for the peer that connected
566 GSF_push_start_ (struct GSF_ConnectedPeer *peer)
568 struct MigrationReadyPeer *mrp;
570 if (GNUNET_YES != enabled)
572 mrp = GNUNET_new (struct MigrationReadyPeer);
575 GNUNET_CONTAINER_DLL_insert (peer_head, peer_tail, mrp);
580 * A peer disconnected from us. Stop pushing content
583 * @param peer handle for the peer that disconnected
586 GSF_push_stop_ (struct GSF_ConnectedPeer *peer)
588 struct MigrationReadyPeer *pos;
593 if (pos->peer == peer)
595 GNUNET_CONTAINER_DLL_remove (peer_head, peer_tail, pos);
598 GSF_peer_transmit_cancel_ (pos->th);
601 if (NULL != pos->msg)
603 GNUNET_free (pos->msg);
621 GNUNET_CONFIGURATION_get_value_yesno (GSF_cfg, "FS", "CONTENT_PUSHING");
622 if (GNUNET_YES != enabled)
626 GNUNET_CONFIGURATION_get_value_time (GSF_cfg, "fs", "MIN_MIGRATION_DELAY",
627 &min_migration_delay))
629 GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_WARNING,
630 "fs", "MIN_MIGRATION_DELAY",
631 _("time required, content pushing disabled"));
634 consider_gathering ();
639 * Shutdown the module.
644 if (GNUNET_SCHEDULER_NO_TASK != mig_task)
646 GNUNET_SCHEDULER_cancel (mig_task);
647 mig_task = GNUNET_SCHEDULER_NO_TASK;
651 GNUNET_DATASTORE_cancel (mig_qe);
654 while (NULL != mig_head)
655 delete_migration_block (mig_head);
656 GNUNET_assert (0 == mig_size);
659 /* end of gnunet-service-fs_push.c */