2 This file is part of GNUnet.
3 (C) 2001, 2002, 2003, 2004, 2005, 2006, 2008, 2009 Christian Grothoff (and other contributing authors)
5 GNUnet is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published
7 by the Free Software Foundation; either version 2, or (at your
8 option) any later version.
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11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
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17 Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA.
21 * @file fs/fs_download.c
22 * @brief download methods
23 * @author Christian Grothoff
26 * - location URI suppport (can wait, easy)
27 * - check if blocks exist already (can wait, easy)
28 * - handle recursive downloads (need directory &
29 * fs-level download-parallelism management, can wait)
30 * - check if iblocks can be computed from existing blocks (can wait, hard)
31 * - persistence (can wait)
34 #include "gnunet_constants.h"
35 #include "gnunet_fs_service.h"
39 #define DEBUG_DOWNLOAD GNUNET_NO
42 * We're storing the IBLOCKS after the
43 * DBLOCKS on disk (so that we only have
44 * to truncate the file once we're done).
46 * Given the offset of a block (with respect
47 * to the DBLOCKS) and its depth, return the
48 * offset where we would store this block
52 * @param fsize overall file size
53 * @param off offset of the block in the file
54 * @param depth depth of the block in the tree
55 * @param treedepth maximum depth of the tree
56 * @return off for DBLOCKS (depth == treedepth),
57 * otherwise an offset past the end
58 * of the file that does not overlap
59 * with the range for any other block
62 compute_disk_offset (uint64_t fsize,
65 unsigned int treedepth)
68 uint64_t lsize; /* what is the size of all IBlocks for level "i"? */
69 uint64_t loff; /* where do IBlocks for level "i" start? */
70 unsigned int ioff; /* which IBlock corresponds to "off" at level "i"? */
72 if (depth == treedepth)
74 /* first IBlocks start at the end of file, rounded up
75 to full DBLOCK_SIZE */
76 loff = ((fsize + DBLOCK_SIZE - 1) / DBLOCK_SIZE) * DBLOCK_SIZE;
77 lsize = ( (fsize + DBLOCK_SIZE-1) / DBLOCK_SIZE) * sizeof (struct ContentHashKey);
78 GNUNET_assert (0 == (off % DBLOCK_SIZE));
79 ioff = (off / DBLOCK_SIZE);
80 for (i=treedepth-1;i>depth;i--)
83 lsize = (lsize + CHK_PER_INODE - 1) / CHK_PER_INODE;
84 GNUNET_assert (lsize > 0);
85 GNUNET_assert (0 == (ioff % CHK_PER_INODE));
86 ioff /= CHK_PER_INODE;
88 return loff + ioff * sizeof (struct ContentHashKey);
93 * Given a file of the specified treedepth and a block at the given
94 * offset and depth, calculate the offset for the CHK at the given
97 * @param offset the offset of the first
98 * DBLOCK in the subtree of the
100 * @param depth the depth of the IBLOCK in the tree
101 * @param treedepth overall depth of the tree
102 * @param k which CHK in the IBLOCK are we
104 * @return offset if k=0, otherwise an appropriately
105 * larger value (i.e., if depth = treedepth-1,
106 * the returned value should be offset+DBLOCK_SIZE)
109 compute_dblock_offset (uint64_t offset,
111 unsigned int treedepth,
115 uint64_t lsize; /* what is the size of the sum of all DBlocks
116 that a CHK at level i corresponds to? */
118 if (depth == treedepth)
121 for (i=treedepth-1;i>depth;i--)
122 lsize *= CHK_PER_INODE;
123 return offset + k * lsize;
128 * Fill in all of the generic fields for
131 * @param pi structure to fill in
132 * @param dc overall download context
135 make_download_status (struct GNUNET_FS_ProgressInfo *pi,
136 struct GNUNET_FS_DownloadContext *dc)
138 pi->value.download.dc = dc;
139 pi->value.download.cctx
141 pi->value.download.pctx
142 = (dc->parent == NULL) ? NULL : dc->parent->client_info;
143 pi->value.download.uri
145 pi->value.download.filename
147 pi->value.download.size
149 pi->value.download.duration
150 = GNUNET_TIME_absolute_get_duration (dc->start_time);
151 pi->value.download.completed
153 pi->value.download.anonymity
158 * We're ready to transmit a search request to the
159 * file-sharing service. Do it. If there is
160 * more than one request pending, try to send
161 * multiple or request another transmission.
164 * @param size number of bytes available in buf
165 * @param buf where the callee should write the message
166 * @return number of bytes written to buf
169 transmit_download_request (void *cls,
175 * Schedule the download of the specified
178 * @param dc overall download this block belongs to
179 * @param chk content-hash-key of the block
180 * @param offset offset of the block in the file
181 * (for IBlocks, the offset is the lowest
182 * offset of any DBlock in the subtree under
184 * @param depth depth of the block, 0 is the root of the tree
187 schedule_block_download (struct GNUNET_FS_DownloadContext *dc,
188 const struct ContentHashKey *chk,
192 struct DownloadRequest *sm;
196 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
197 "Scheduling download at offset %llu and depth %u for `%s'\n",
198 (unsigned long long) offset,
200 GNUNET_h2s (&chk->query));
202 off = compute_disk_offset (GNUNET_ntohll (dc->uri->data.chk.file_length),
206 if ( (dc->old_file_size > off) &&
207 (dc->handle != NULL) &&
209 GNUNET_DISK_file_seek (dc->handle,
211 GNUNET_DISK_SEEK_SET) ) )
213 // FIXME: check if block exists on disk!
214 // (read block, encode, compare with
215 // query; if matches, simply return)
217 if (depth < dc->treedepth)
219 // FIXME: try if we could
220 // reconstitute this IBLOCK
221 // from the existing blocks on disk (can wait)
222 // (read block(s), encode, compare with
223 // query; if matches, simply return)
225 sm = GNUNET_malloc (sizeof (struct DownloadRequest));
229 sm->is_pending = GNUNET_YES;
230 sm->next = dc->pending;
232 GNUNET_CONTAINER_multihashmap_put (dc->active,
235 GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE);
237 if ( (dc->th == NULL) &&
238 (dc->client != NULL) )
239 dc->th = GNUNET_CLIENT_notify_transmit_ready (dc->client,
240 sizeof (struct SearchMessage),
241 GNUNET_CONSTANTS_SERVICE_TIMEOUT,
242 &transmit_download_request,
249 * We've lost our connection with the FS service.
250 * Re-establish it and re-transmit all of our
253 * @param dc download context that is having trouble
256 try_reconnect (struct GNUNET_FS_DownloadContext *dc);
260 * Compute how many bytes of data should be stored in
261 * the specified node.
263 * @param fsize overall file size
264 * @param totaldepth depth of the entire tree
265 * @param offset offset of the node
266 * @param depth depth of the node
267 * @return number of bytes stored in this node
270 calculate_block_size (uint64_t fsize,
271 unsigned int totaldepth,
281 GNUNET_assert (offset < fsize);
282 if (depth == totaldepth)
285 if (offset + ret > fsize)
286 ret = (size_t) (fsize - offset);
291 for (i = totaldepth-1; i > depth; i--)
292 rsize *= CHK_PER_INODE;
293 epos = offset + rsize * CHK_PER_INODE;
294 GNUNET_assert (epos > offset);
297 /* round up when computing #CHKs in our IBlock */
298 chks = (epos - offset + rsize - 1) / rsize;
299 GNUNET_assert (chks <= CHK_PER_INODE);
300 return chks * sizeof (struct ContentHashKey);
305 * Process a download result.
307 * @param dc our download context
308 * @param type type of the result
309 * @param data the (encrypted) response
310 * @param size size of data
313 process_result (struct GNUNET_FS_DownloadContext *dc,
318 struct GNUNET_FS_ProgressInfo pi;
319 GNUNET_HashCode query;
320 struct DownloadRequest *sm;
321 struct GNUNET_CRYPTO_AesSessionKey skey;
322 struct GNUNET_CRYPTO_AesInitializationVector iv;
327 struct ContentHashKey *chk;
331 GNUNET_CRYPTO_hash (data, size, &query);
333 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
334 "Received result for query `%s' from `%s'-service\n",
338 sm = GNUNET_CONTAINER_multihashmap_get (dc->active,
345 if (size != calculate_block_size (GNUNET_ntohll (dc->uri->data.chk.file_length),
351 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
352 "Internal error or bogus download URI (expected %u bytes, got %u)\n",
353 calculate_block_size (GNUNET_ntohll (dc->uri->data.chk.file_length),
359 dc->emsg = GNUNET_strdup ("Internal error or bogus download URI");
361 pi.status = GNUNET_FS_STATUS_DOWNLOAD_ERROR;
362 make_download_status (&pi, dc);
363 pi.value.download.specifics.error.message = dc->emsg;
364 dc->client_info = dc->h->upcb (dc->h->upcb_cls,
366 /* abort all pending requests */
369 GNUNET_CONNECTION_notify_transmit_ready_cancel (dc->th);
372 GNUNET_CLIENT_disconnect (dc->client);
376 GNUNET_assert (GNUNET_YES ==
377 GNUNET_CONTAINER_multihashmap_remove (dc->active,
380 GNUNET_CRYPTO_hash_to_aes_key (&sm->chk.key, &skey, &iv);
381 GNUNET_CRYPTO_aes_decrypt (data,
387 if ( (NULL != dc->handle) &&
388 ( (sm->depth == dc->treedepth) ||
389 (0 == (dc->options & GNUNET_FS_DOWNLOAD_NO_TEMPORARIES)) ) )
391 off = compute_disk_offset (GNUNET_ntohll (dc->uri->data.chk.file_length),
397 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
398 "Saving decrypted block to disk at offset %llu\n",
399 (unsigned long long) off);
402 GNUNET_DISK_file_seek (dc->handle,
404 GNUNET_DISK_SEEK_SET) ) )
405 GNUNET_asprintf (&emsg,
406 _("Failed to seek to offset %llu in file `%s': %s\n"),
407 (unsigned long long) off,
411 GNUNET_DISK_file_write (dc->handle,
414 GNUNET_asprintf (&emsg,
415 _("Failed to write block of %u bytes at offset %llu in file `%s': %s\n"),
417 (unsigned long long) off,
423 // FIXME: make persistent
426 pi.status = GNUNET_FS_STATUS_DOWNLOAD_ERROR;
427 make_download_status (&pi, dc);
428 pi.value.download.specifics.error.message = emsg;
429 dc->client_info = dc->h->upcb (dc->h->upcb_cls,
432 /* abort all pending requests */
435 GNUNET_CONNECTION_notify_transmit_ready_cancel (dc->th);
438 GNUNET_CLIENT_disconnect (dc->client);
444 if (sm->depth == dc->treedepth)
447 if (sm->offset < dc->offset)
449 /* starting offset begins in the middle of pt,
450 do not count first bytes as progress */
451 GNUNET_assert (app > (dc->offset - sm->offset));
452 app -= (dc->offset - sm->offset);
454 if (sm->offset + size > dc->offset + dc->length)
456 /* end of block is after relevant range,
457 do not count last bytes as progress */
458 GNUNET_assert (app > (sm->offset + size) - (dc->offset + dc->length));
459 app -= (sm->offset + size) - (dc->offset + dc->length);
461 dc->completed += app;
464 pi.status = GNUNET_FS_STATUS_DOWNLOAD_PROGRESS;
465 make_download_status (&pi, dc);
466 pi.value.download.specifics.progress.data = pt;
467 pi.value.download.specifics.progress.offset = sm->offset;
468 pi.value.download.specifics.progress.data_len = size;
469 pi.value.download.specifics.progress.depth = sm->depth;
470 dc->client_info = dc->h->upcb (dc->h->upcb_cls,
472 GNUNET_assert (dc->completed <= dc->length);
473 if (dc->completed == dc->length)
476 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
477 "Download completed, truncating file to desired length %llu\n",
478 (unsigned long long) GNUNET_ntohll (dc->uri->data.chk.file_length));
480 /* truncate file to size (since we store IBlocks at the end) */
481 if (dc->handle != NULL)
483 GNUNET_DISK_file_close (dc->handle);
485 if (0 != truncate (dc->filename,
486 GNUNET_ntohll (dc->uri->data.chk.file_length)))
487 GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING,
491 /* signal completion */
492 pi.status = GNUNET_FS_STATUS_DOWNLOAD_COMPLETED;
493 make_download_status (&pi, dc);
494 dc->client_info = dc->h->upcb (dc->h->upcb_cls,
496 GNUNET_assert (sm->depth == dc->treedepth);
498 // FIXME: make persistent
499 if (sm->depth == dc->treedepth)
505 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
506 "Triggering downloads of children (this block was at level %u and offset %llu)\n",
508 (unsigned long long) sm->offset);
510 GNUNET_assert (0 == (size % sizeof(struct ContentHashKey)));
511 chk = (struct ContentHashKey*) pt;
512 for (i=(size / sizeof(struct ContentHashKey))-1;i>=0;i--)
514 off = compute_dblock_offset (sm->offset,
518 if ( (off + DBLOCK_SIZE >= dc->offset) &&
519 (off < dc->offset + dc->length) )
520 schedule_block_download (dc,
530 * Type of a function to call when we receive a message
534 * @param msg message received, NULL on timeout or fatal error
537 receive_results (void *cls,
538 const struct GNUNET_MessageHeader * msg)
540 struct GNUNET_FS_DownloadContext *dc = cls;
541 const struct ContentMessage *cm;
544 if ( (NULL == msg) ||
545 (ntohs (msg->type) != GNUNET_MESSAGE_TYPE_FS_CONTENT) ||
546 (ntohs (msg->size) <= sizeof (struct ContentMessage)) )
551 msize = ntohs (msg->size);
552 cm = (const struct ContentMessage*) msg;
556 msize - sizeof (struct ContentMessage));
557 if (dc->client == NULL)
558 return; /* fatal error */
559 /* continue receiving */
560 GNUNET_CLIENT_receive (dc->client,
563 GNUNET_TIME_UNIT_FOREVER_REL);
569 * We're ready to transmit a search request to the
570 * file-sharing service. Do it. If there is
571 * more than one request pending, try to send
572 * multiple or request another transmission.
575 * @param size number of bytes available in buf
576 * @param buf where the callee should write the message
577 * @return number of bytes written to buf
580 transmit_download_request (void *cls,
584 struct GNUNET_FS_DownloadContext *dc = cls;
586 struct SearchMessage *sm;
594 GNUNET_assert (size >= sizeof (struct SearchMessage));
597 while ( (dc->pending != NULL) &&
598 (size > msize + sizeof (struct SearchMessage)) )
601 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
602 "Transmitting download request for `%s' to `%s'-service\n",
603 GNUNET_h2s (&dc->pending->chk.query),
606 memset (sm, 0, sizeof (struct SearchMessage));
607 sm->header.size = htons (sizeof (struct SearchMessage));
608 sm->header.type = htons (GNUNET_MESSAGE_TYPE_FS_START_SEARCH);
609 sm->anonymity_level = htonl (dc->anonymity);
610 sm->target = dc->target.hashPubKey;
611 sm->query = dc->pending->chk.query;
612 dc->pending->is_pending = GNUNET_NO;
613 dc->pending = dc->pending->next;
614 msize += sizeof (struct SearchMessage);
617 if (dc->pending != NULL)
618 dc->th = GNUNET_CLIENT_notify_transmit_ready (dc->client,
619 sizeof (struct SearchMessage),
620 GNUNET_CONSTANTS_SERVICE_TIMEOUT,
621 &transmit_download_request,
628 * Reconnect to the FS service and transmit
631 * @param cls our download context
635 do_reconnect (void *cls,
636 const struct GNUNET_SCHEDULER_TaskContext *tc)
638 struct GNUNET_FS_DownloadContext *dc = cls;
639 struct GNUNET_CLIENT_Connection *client;
641 dc->task = GNUNET_SCHEDULER_NO_TASK;
642 client = GNUNET_CLIENT_connect (dc->h->sched,
647 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
648 "Connecting to `%s'-service failed, will try again.\n",
654 dc->th = GNUNET_CLIENT_notify_transmit_ready (client,
655 sizeof (struct SearchMessage),
656 GNUNET_CONSTANTS_SERVICE_TIMEOUT,
657 &transmit_download_request,
659 GNUNET_CLIENT_receive (client,
662 GNUNET_TIME_UNIT_FOREVER_REL);
667 * Add entries that are not yet pending back to the pending list.
669 * @param cls our download context
671 * @param entry entry of type "struct DownloadRequest"
675 retry_entry (void *cls,
676 const GNUNET_HashCode *key,
679 struct GNUNET_FS_DownloadContext *dc = cls;
680 struct DownloadRequest *dr = entry;
682 if (! dr->is_pending)
684 dr->next = dc->pending;
685 dr->is_pending = GNUNET_YES;
693 * We've lost our connection with the FS service.
694 * Re-establish it and re-transmit all of our
697 * @param dc download context that is having trouble
700 try_reconnect (struct GNUNET_FS_DownloadContext *dc)
703 if (NULL != dc->client)
707 GNUNET_CONNECTION_notify_transmit_ready_cancel (dc->th);
710 GNUNET_CONTAINER_multihashmap_iterate (dc->active,
713 GNUNET_CLIENT_disconnect (dc->client);
717 = GNUNET_SCHEDULER_add_delayed (dc->h->sched,
719 GNUNET_SCHEDULER_PRIORITY_IDLE,
720 GNUNET_SCHEDULER_NO_TASK,
721 GNUNET_TIME_UNIT_SECONDS,
728 * Download parts of a file. Note that this will store
729 * the blocks at the respective offset in the given file. Also, the
730 * download is still using the blocking of the underlying FS
731 * encoding. As a result, the download may *write* outside of the
732 * given boundaries (if offset and length do not match the 32k FS
733 * block boundaries). <p>
735 * This function should be used to focus a download towards a
736 * particular portion of the file (optimization), not to strictly
737 * limit the download to exactly those bytes.
739 * @param h handle to the file sharing subsystem
740 * @param uri the URI of the file (determines what to download); CHK or LOC URI
741 * @param meta known metadata for the file (can be NULL)
742 * @param filename where to store the file, maybe NULL (then no file is
743 * created on disk and data must be grabbed from the callbacks)
744 * @param offset at what offset should we start the download (typically 0)
745 * @param length how many bytes should be downloaded starting at offset
746 * @param anonymity anonymity level to use for the download
747 * @param options various options
748 * @param cctx initial value for the client context for this download
749 * @param parent parent download to associate this download with (use NULL
750 * for top-level downloads; useful for manually-triggered recursive downloads)
751 * @return context that can be used to control this download
753 struct GNUNET_FS_DownloadContext *
754 GNUNET_FS_download_start (struct GNUNET_FS_Handle *h,
755 const struct GNUNET_FS_Uri *uri,
756 const struct GNUNET_CONTAINER_MetaData *meta,
757 const char *filename,
761 enum GNUNET_FS_DownloadOptions options,
763 struct GNUNET_FS_DownloadContext *parent)
765 struct GNUNET_FS_ProgressInfo pi;
766 struct GNUNET_FS_DownloadContext *dc;
767 struct GNUNET_CLIENT_Connection *client;
769 GNUNET_assert (GNUNET_FS_uri_test_chk (uri));
770 if ( (offset + length < offset) ||
771 (offset + length > uri->data.chk.file_length) )
776 client = GNUNET_CLIENT_connect (h->sched,
781 // FIXME: add support for "loc" URIs!
783 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
784 "Starting download `%s' of %llu bytes\n",
786 (unsigned long long) length);
788 dc = GNUNET_malloc (sizeof(struct GNUNET_FS_DownloadContext));
792 dc->uri = GNUNET_FS_uri_dup (uri);
793 dc->meta = GNUNET_CONTAINER_meta_data_duplicate (meta);
794 dc->client_info = cctx;
795 if (NULL != filename)
797 dc->filename = GNUNET_strdup (filename);
798 if (GNUNET_YES == GNUNET_DISK_file_test (filename))
799 GNUNET_DISK_file_size (filename,
802 dc->handle = GNUNET_DISK_file_open (filename,
803 GNUNET_DISK_OPEN_READWRITE |
804 GNUNET_DISK_OPEN_CREATE,
805 GNUNET_DISK_PERM_USER_READ |
806 GNUNET_DISK_PERM_USER_WRITE |
807 GNUNET_DISK_PERM_GROUP_READ |
808 GNUNET_DISK_PERM_OTHER_READ);
809 if (dc->handle == NULL)
811 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
812 _("Download failed: could not open file `%s': %s\n"),
815 GNUNET_CONTAINER_meta_data_destroy (dc->meta);
816 GNUNET_FS_uri_destroy (dc->uri);
817 GNUNET_free (dc->filename);
818 GNUNET_CLIENT_disconnect (dc->client);
823 // FIXME: set "dc->target" for LOC uris!
826 dc->anonymity = anonymity;
827 dc->options = options;
828 dc->active = GNUNET_CONTAINER_multihashmap_create (2 * (length / DBLOCK_SIZE));
829 dc->treedepth = GNUNET_FS_compute_depth (GNUNET_ntohll(dc->uri->data.chk.file_length));
831 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
832 "Download tree has depth %u\n",
835 // FIXME: make persistent
836 schedule_block_download (dc,
837 &dc->uri->data.chk.chk,
839 1 /* 0 == CHK, 1 == top */);
840 GNUNET_CLIENT_receive (client,
843 GNUNET_TIME_UNIT_FOREVER_REL);
844 pi.status = GNUNET_FS_STATUS_DOWNLOAD_START;
845 make_download_status (&pi, dc);
846 pi.value.download.specifics.start.meta = meta;
847 dc->client_info = dc->h->upcb (dc->h->upcb_cls,
855 * Free entries in the map.
857 * @param cls unused (NULL)
859 * @param entry entry of type "struct DownloadRequest" which is freed
863 free_entry (void *cls,
864 const GNUNET_HashCode *key,
873 * Stop a download (aborts if download is incomplete).
875 * @param dc handle for the download
876 * @param do_delete delete files of incomplete downloads
879 GNUNET_FS_download_stop (struct GNUNET_FS_DownloadContext *dc,
882 struct GNUNET_FS_ProgressInfo pi;
884 // FIXME: make unpersistent
885 pi.status = GNUNET_FS_STATUS_DOWNLOAD_STOPPED;
886 make_download_status (&pi, dc);
887 dc->client_info = dc->h->upcb (dc->h->upcb_cls,
890 if (GNUNET_SCHEDULER_NO_TASK != dc->task)
891 GNUNET_SCHEDULER_cancel (dc->h->sched,
895 GNUNET_CONNECTION_notify_transmit_ready_cancel (dc->th);
898 if (NULL != dc->client)
899 GNUNET_CLIENT_disconnect (dc->client);
900 GNUNET_CONTAINER_multihashmap_iterate (dc->active,
903 GNUNET_CONTAINER_multihashmap_destroy (dc->active);
904 if (dc->filename != NULL)
906 if (NULL != dc->handle)
907 GNUNET_DISK_file_close (dc->handle);
908 if ( (dc->completed != dc->length) &&
909 (GNUNET_YES == do_delete) )
911 if (0 != UNLINK (dc->filename))
912 GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING,
916 GNUNET_free (dc->filename);
918 GNUNET_CONTAINER_meta_data_destroy (dc->meta);
919 GNUNET_FS_uri_destroy (dc->uri);
929 * Check if self block is already present on the drive. If the block
930 * is a dblock and present, the ProgressModel is notified. If the
931 * block is present and it is an iblock, downloading the children is
934 * Also checks if the block is within the range of blocks
935 * that we are supposed to download. If not, the method
936 * returns as if the block is present but does NOT signal
939 * @param node that is checked for presence
940 * @return GNUNET_YES if present, GNUNET_NO if not.
943 check_node_present (const struct Node *node)
951 size = get_node_size (node);
952 /* first check if node is within range.
953 For now, keeping it simple, we only do
954 this for level-0 nodes */
955 if ((node->level == 0) &&
956 ((node->offset + size < node->ctx->offset) ||
957 (node->offset >= node->ctx->offset + node->ctx->length)))
959 data = GNUNET_malloc (size);
961 res = read_from_files (node->ctx, node->level, node->offset, data, size);
964 GNUNET_hash (data, size, &hc);
965 if (0 == memcmp (&hc, &node->chk.key, sizeof (GNUNET_HashCode)))
967 notify_client_about_progress (node, data, size);
969 iblock_download_children (node, data, size);
980 /* end of fs_download.c */