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 * How long must content remain valid for us to consider it for migration?
36 * If content will expire too soon, there is clearly no point in pushing
37 * it to other peers. This value gives the threshold for migration. Note
38 * that if this value is increased, the migration testcase may need to be
39 * adjusted as well (especially the CONTENT_LIFETIME in fs_test_lib.c).
41 #define MIN_MIGRATION_CONTENT_LIFETIME GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, 30)
45 * Block that is ready for migration to other peers. Actual data is at the end of the block.
47 struct MigrationReadyBlock
51 * This is a doubly-linked list.
53 struct MigrationReadyBlock *next;
56 * This is a doubly-linked list.
58 struct MigrationReadyBlock *prev;
61 * Query for the block.
63 GNUNET_HashCode query;
66 * When does this block expire?
68 struct GNUNET_TIME_Absolute expiration;
71 * Peers we already forwarded this
72 * block to. Zero for empty entries.
74 GNUNET_PEER_Id target_list[MIGRATION_LIST_SIZE];
82 * Number of targets already used.
84 unsigned int used_targets;
89 enum GNUNET_BLOCK_Type type;
94 * Information about a peer waiting for
97 struct MigrationReadyPeer
100 * This is a doubly-linked list.
102 struct MigrationReadyPeer *next;
105 * This is a doubly-linked list.
107 struct MigrationReadyPeer *prev;
112 struct GSF_ConnectedPeer *peer;
115 * Handle for current transmission request,
118 struct GSF_PeerTransmitHandle *th;
121 * Message we are trying to push right now (or NULL)
123 struct PutMessage *msg;
128 * Head of linked list of blocks that can be migrated.
130 static struct MigrationReadyBlock *mig_head;
133 * Tail of linked list of blocks that can be migrated.
135 static struct MigrationReadyBlock *mig_tail;
138 * Head of linked list of peers.
140 static struct MigrationReadyPeer *peer_head;
143 * Tail of linked list of peers.
145 static struct MigrationReadyPeer *peer_tail;
148 * Request to datastore for migration (or NULL).
150 static struct GNUNET_DATASTORE_QueueEntry *mig_qe;
153 * ID of task that collects blocks for migration.
155 static GNUNET_SCHEDULER_TaskIdentifier mig_task;
158 * What is the maximum frequency at which we are allowed to
159 * poll the datastore for migration content?
161 static struct GNUNET_TIME_Relative min_migration_delay;
164 * Size of the doubly-linked list of migration blocks.
166 static unsigned int mig_size;
169 * Is this module enabled?
175 * Delete the given migration block.
177 * @param mb block to delete
180 delete_migration_block (struct MigrationReadyBlock *mb)
182 GNUNET_CONTAINER_DLL_remove (mig_head,
185 GNUNET_PEER_decrement_rcs (mb->target_list,
186 MIGRATION_LIST_SIZE);
193 * Find content for migration to this peer.
196 find_content (struct MigrationReadyPeer *mrp);
200 * Transmit the message currently scheduled for
203 * @param cls the 'struct MigrationReadyPeer'
204 * @param buf_size number of bytes available in buf
205 * @param buf where to copy the message, NULL on error (peer disconnect)
206 * @return number of bytes copied to 'buf', can be 0 (without indicating an error)
209 transmit_message (void *cls,
213 struct MigrationReadyPeer *peer = cls;
214 struct PutMessage *msg;
225 msize = ntohs (msg->header.size);
226 GNUNET_assert (msize <= buf_size);
227 memcpy (buf, msg, msize);
235 * Send the given block to the given peer.
237 * @param peer target peer
238 * @param block the block
239 * @return GNUNET_YES if the block was deleted (!)
242 transmit_content (struct MigrationReadyPeer *peer,
243 struct MigrationReadyBlock *block)
246 struct PutMessage *msg;
248 struct GSF_PeerPerformanceData *ppd;
251 ppd = GSF_get_peer_performance_data_ (peer->peer);
252 GNUNET_assert (NULL == peer->th);
253 msize = sizeof (struct PutMessage) + block->size;
254 msg = GNUNET_malloc (msize);
255 msg->header.type = htons (42);
256 msg->header.size = htons (msize);
262 for (i=0;i<MIGRATION_LIST_SIZE;i++)
264 if (block->target_list[i] == 0)
266 block->target_list[i] = ppd->pid;
267 GNUNET_PEER_change_rc (block->target_list[i], 1);
271 if (MIGRATION_LIST_SIZE == i)
273 delete_migration_block (block);
280 peer->th = GSF_peer_transmit_ (peer->peer,
283 GNUNET_TIME_UNIT_FOREVER_REL,
292 * Count the number of peers this block has
293 * already been forwarded to.
295 * @param block the block
296 * @return number of times block was forwarded
299 count_targets (struct MigrationReadyBlock *block)
303 for (i=0;i<MIGRATION_LIST_SIZE;i++)
304 if (block->target_list[i] == 0)
311 * Check if sending this block to this peer would
314 * @param peer target peer
315 * @param block the block
316 * @return score (>= 0: feasible, negative: infeasible)
319 score_content (struct MigrationReadyPeer *peer,
320 struct MigrationReadyBlock *block)
323 struct GSF_PeerPerformanceData *ppd;
324 struct GNUNET_PeerIdentity id;
327 ppd = GSF_get_peer_performance_data_ (peer->peer);
328 for (i=0;i<MIGRATION_LIST_SIZE;i++)
329 if (block->target_list[i] == ppd->pid)
331 GNUNET_PEER_resolve (ppd->pid,
333 dist = GNUNET_CRYPTO_hash_distance_u32 (&block->query,
335 /* closer distance, higher score: */
336 return UINT32_MAX - dist;
341 * If the migration task is not currently running, consider
342 * (re)scheduling it with the appropriate delay.
345 consider_gathering (void);
349 * Find content for migration to this peer.
351 * @param mrp peer to find content for
354 find_content (struct MigrationReadyPeer *mrp)
356 struct MigrationReadyBlock *pos;
359 struct MigrationReadyBlock *best;
361 GNUNET_assert (NULL == mrp->th);
367 score = score_content (mrp, pos);
368 if (score > best_score)
377 if (mig_size < MAX_MIGRATION_QUEUE)
378 return; /* will fill up eventually... */
379 /* failed to find migration target AND
380 queue is full, purge most-forwarded
381 block from queue to make room for more */
386 score = count_targets (pos);
387 if (score >= best_score)
394 GNUNET_assert (NULL != best);
395 delete_migration_block (best);
396 consider_gathering ();
399 transmit_content (mrp, best);
404 * Task that is run periodically to obtain blocks for content
408 * @param tc scheduler context (also unused)
411 gather_migration_blocks (void *cls,
412 const struct GNUNET_SCHEDULER_TaskContext *tc);
416 * If the migration task is not currently running, consider
417 * (re)scheduling it with the appropriate delay.
420 consider_gathering ()
422 struct GNUNET_TIME_Relative delay;
428 if (mig_task != GNUNET_SCHEDULER_NO_TASK)
430 if (mig_size >= MAX_MIGRATION_QUEUE)
432 delay = GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS,
434 delay = GNUNET_TIME_relative_divide (delay,
435 MAX_MIGRATION_QUEUE);
436 delay = GNUNET_TIME_relative_max (delay,
437 min_migration_delay);
438 mig_task = GNUNET_SCHEDULER_add_delayed (delay,
439 &gather_migration_blocks,
445 * Process content offered for migration.
448 * @param key key for the content
449 * @param size number of bytes in data
450 * @param data content stored
451 * @param type type of the content
452 * @param priority priority of the content
453 * @param anonymity anonymity-level for the content
454 * @param expiration expiration time for the content
455 * @param uid unique identifier for the datum;
456 * maybe 0 if no unique identifier is available
459 process_migration_content (void *cls,
460 const GNUNET_HashCode * key,
463 enum GNUNET_BLOCK_Type type,
466 struct GNUNET_TIME_Absolute
467 expiration, uint64_t uid)
469 struct MigrationReadyBlock *mb;
470 struct MigrationReadyPeer *pos;
475 consider_gathering ();
478 if (GNUNET_TIME_absolute_get_remaining (expiration).rel_value <
479 MIN_MIGRATION_CONTENT_LIFETIME.rel_value)
481 /* content will expire soon, don't bother */
482 GNUNET_DATASTORE_get_next (GSF_dsh);
485 if (type == GNUNET_BLOCK_TYPE_FS_ONDEMAND)
488 GNUNET_FS_handle_on_demand_block (key, size, data,
489 type, priority, anonymity,
491 &process_migration_content,
494 GNUNET_DATASTORE_get_next (GSF_dsh);
499 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
500 "Retrieved block `%s' of type %u for migration\n",
504 mb = GNUNET_malloc (sizeof (struct MigrationReadyBlock) + size);
506 mb->expiration = expiration;
509 memcpy (&mb[1], data, size);
510 GNUNET_CONTAINER_DLL_insert_after (mig_head,
520 if (GNUNET_YES == transmit_content (pos, mb))
521 break; /* 'mb' was freed! */
525 GNUNET_DATASTORE_get_next (GSF_dsh);
530 * Task that is run periodically to obtain blocks for content
534 * @param tc scheduler context (also unused)
537 gather_migration_blocks (void *cls,
538 const struct GNUNET_SCHEDULER_TaskContext *tc)
540 mig_task = GNUNET_SCHEDULER_NO_TASK;
543 mig_qe = GNUNET_DATASTORE_get_random (GSF_dsh,
545 GNUNET_TIME_UNIT_FOREVER_REL,
546 &process_migration_content, NULL);
547 GNUNET_assert (mig_qe != NULL);
553 * A peer connected to us. Start pushing content
556 * @param peer handle for the peer that connected
559 GSF_push_start_ (struct GSF_ConnectedPeer *peer)
561 struct MigrationReadyPeer *mrp;
563 if (GNUNET_YES != enabled)
565 mrp = GNUNET_malloc (sizeof (struct MigrationReadyPeer));
568 GNUNET_CONTAINER_DLL_insert (peer_head,
575 * A peer disconnected from us. Stop pushing content
578 * @param peer handle for the peer that disconnected
581 GSF_push_stop_ (struct GSF_ConnectedPeer *peer)
583 struct MigrationReadyPeer *pos;
588 if (pos->peer == peer)
590 GNUNET_CONTAINER_DLL_remove (peer_head,
594 GSF_peer_transmit_cancel_ (pos->th);
609 enabled = GNUNET_CONFIGURATION_get_value_yesno (GSF_cfg,
612 if (GNUNET_YES != enabled)
616 GNUNET_CONFIGURATION_get_value_time (GSF_cfg,
618 "MIN_MIGRATION_DELAY",
619 &min_migration_delay))
621 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
622 _("Invalid value specified for option `%s' in section `%s', content pushing disabled\n"),
623 "MIN_MIGRATION_DELAY",
627 consider_gathering ();
632 * Shutdown the module.
637 if (GNUNET_SCHEDULER_NO_TASK != mig_task)
639 GNUNET_SCHEDULER_cancel (mig_task);
640 mig_task = GNUNET_SCHEDULER_NO_TASK;
644 GNUNET_DATASTORE_cancel (mig_qe);
647 while (NULL != mig_head)
648 delete_migration_block (mig_head);
649 GNUNET_assert (0 == mig_size);
652 /* end of gnunet-service-fs_push.c */