convert download API to MQ

5 files changed, 249 insertions, 377 deletions

diff --git a/src/fs/fs_api.c b/src/fs/fs_api.c
index 2db475528..0bc07183e 100644
--- a/src/fs/fs_api.c
+++ b/src/fs/fs_api.c
@@ -49,14 +49,8 @@
 static void
 start_job (struct GNUNET_FS_QueueEntry *qe)
 {
-  GNUNET_assert (NULL == qe->client);
-  qe->client = GNUNET_CLIENT_connect ("fs", qe->h->cfg);
-  if (NULL == qe->client)
-  {
-    GNUNET_break (0);
-    return;
-  }
-  qe->start (qe->cls, qe->client);
+  qe->active = GNUNET_YES;
+  qe->start (qe->cls);
   qe->start_times++;
   qe->h->active_blocks += qe->blocks;
   qe->h->active_downloads++;
@@ -84,7 +78,7 @@ start_job (struct GNUNET_FS_QueueEntry *qe)
 static void
 stop_job (struct GNUNET_FS_QueueEntry *qe)
 {
-  qe->client = NULL;
+  qe->active = GNUNET_NO;
   qe->stop (qe->cls);
   GNUNET_assert (0 < qe->h->active_downloads);
   qe->h->active_downloads--;
@@ -97,9 +91,13 @@ stop_job (struct GNUNET_FS_QueueEntry *qe)
               "Stopping job %p (%u active)\n",
               qe,
               qe->h->active_downloads);
-  GNUNET_CONTAINER_DLL_remove (qe->h->running_head, qe->h->running_tail, qe);
-  GNUNET_CONTAINER_DLL_insert_after (qe->h->pending_head, qe->h->pending_tail,
-                                     qe->h->pending_tail, qe);
+  GNUNET_CONTAINER_DLL_remove (qe->h->running_head,
+                               qe->h->running_tail,
+                               qe);
+  GNUNET_CONTAINER_DLL_insert_after (qe->h->pending_head,
+                                     qe->h->pending_tail,
+                                     qe->h->pending_tail,
+                                     qe);
 }
 
 
@@ -328,8 +326,9 @@ process_job_queue (void *cls)
  */
 struct GNUNET_FS_QueueEntry *
 GNUNET_FS_queue_ (struct GNUNET_FS_Handle *h,
-                  GNUNET_FS_QueueStart start,
-                  GNUNET_FS_QueueStop stop, void *cls,
+                  GNUNET_SCHEDULER_TaskCallback start,
+                  GNUNET_SCHEDULER_TaskCallback stop,
+                  void *cls,
                   unsigned int blocks,
                   enum GNUNET_FS_QueuePriority priority)
 {
@@ -369,13 +368,16 @@ GNUNET_FS_dequeue_ (struct GNUNET_FS_QueueEntry *qe)
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
               "Dequeueing job %p\n",
               qe);
-  if (NULL != qe->client)
+  if (GNUNET_YES == qe->active)
     stop_job (qe);
-  GNUNET_CONTAINER_DLL_remove (h->pending_head, h->pending_tail, qe);
+  GNUNET_CONTAINER_DLL_remove (h->pending_head,
+                               h->pending_tail,
+                               qe);
   GNUNET_free (qe);
   if (NULL != h->queue_job)
     GNUNET_SCHEDULER_cancel (h->queue_job);
-  h->queue_job = GNUNET_SCHEDULER_add_now (&process_job_queue, h);
+  h->queue_job = GNUNET_SCHEDULER_add_now (&process_job_queue,
+                                           h);
 }
 
 
@@ -397,7 +399,9 @@ GNUNET_FS_make_top (struct GNUNET_FS_Handle *h,
   ret = GNUNET_new (struct TopLevelActivity);
   ret->ssf = ssf;
   ret->ssf_cls = ssf_cls;
-  GNUNET_CONTAINER_DLL_insert (h->top_head, h->top_tail, ret);
+  GNUNET_CONTAINER_DLL_insert (h->top_head,
+                               h->top_tail,
+                               ret);
   return ret;
 }
 
@@ -412,7 +416,9 @@ void
 GNUNET_FS_end_top (struct GNUNET_FS_Handle *h,
                    struct TopLevelActivity *top)
 {
-  GNUNET_CONTAINER_DLL_remove (h->top_head, h->top_tail, top);
+  GNUNET_CONTAINER_DLL_remove (h->top_head,
+                               h->top_tail,
+                               top);
   GNUNET_free (top);
 }
 
@@ -2531,8 +2537,7 @@ signal_download_resume (struct GNUNET_FS_DownloadContext *dc)
     signal_download_resume (dcc);
     dcc = dcc->next;
   }
-  if (NULL != dc->pending_head)
-    GNUNET_FS_download_start_downloading_ (dc);
+  GNUNET_FS_download_start_downloading_ (dc);
 }
 
 
@@ -2815,12 +2820,16 @@ deserialize_download (struct GNUNET_FS_Handle *h,
   if (NULL != dn)
   {
     if (GNUNET_YES == GNUNET_DISK_directory_test (dn, GNUNET_YES))
-      GNUNET_DISK_directory_scan (dn, &deserialize_subdownload, dc);
+      GNUNET_DISK_directory_scan (dn,
+                                  &deserialize_subdownload,
+                                  dc);
     GNUNET_free (dn);
   }
   if (NULL != parent)
   {
-    GNUNET_CONTAINER_DLL_insert (parent->child_head, parent->child_tail, dc);
+    GNUNET_CONTAINER_DLL_insert (parent->child_head,
+                                 parent->child_tail,
+                                 dc);
   }
   if (NULL != search)
   {
@@ -2830,11 +2839,14 @@ deserialize_download (struct GNUNET_FS_Handle *h,
   if ((NULL == parent) && (NULL == search))
   {
     dc->top =
-        GNUNET_FS_make_top (dc->h, &GNUNET_FS_download_signal_suspend_, dc);
+        GNUNET_FS_make_top (dc->h,
+                            &GNUNET_FS_download_signal_suspend_,
+                            dc);
     signal_download_resume (dc);
   }
   GNUNET_free (uris);
-  dc->task = GNUNET_SCHEDULER_add_now (&GNUNET_FS_download_start_task_, dc);
+  dc->task = GNUNET_SCHEDULER_add_now (&GNUNET_FS_download_start_task_,
+                                       dc);
   return;
 cleanup:
   GNUNET_free_non_null (uris);
diff --git a/src/fs/fs_api.h b/src/fs/fs_api.h
index 398de27fd..86219b3f8 100644
--- a/src/fs/fs_api.h
+++ b/src/fs/fs_api.h
@@ -410,27 +410,6 @@ struct GNUNET_FS_FileInformation
 
 
 /**
- * The job is now ready to run and should use the given client
- * handle to communicate with the FS service.
- *
- * @param cls closure
- * @param client handle to use for FS communication
- */
-typedef void
-(*GNUNET_FS_QueueStart) (void *cls,
-                         struct GNUNET_CLIENT_Connection *client);
-
-
-/**
- * The job must now stop to run and should destry the client handle as
- * soon as possible (ideally prior to returning).
- */
-typedef void
-(*GNUNET_FS_QueueStop) (void *cls);
-
-
-
-/**
  * Priorities for the queue.
  */
 enum GNUNET_FS_QueuePriority
@@ -465,12 +444,12 @@ struct GNUNET_FS_QueueEntry
   /**
    * Function to call when the job is started.
    */
-  GNUNET_FS_QueueStart start;
+  GNUNET_SCHEDULER_TaskCallback start;
 
   /**
    * Function to call when the job needs to stop (or is done / dequeued).
    */
-  GNUNET_FS_QueueStop stop;
+  GNUNET_SCHEDULER_TaskCallback stop;
 
   /**
    * Closure for start and stop.
@@ -483,9 +462,9 @@ struct GNUNET_FS_QueueEntry
   struct GNUNET_FS_Handle *h;
 
   /**
-   * Client handle, or NULL if job is not running.
+   * Message queue handle, or NULL if job is not running.
    */
-  struct GNUNET_CLIENT_Connection *client;
+  struct GNUNET_MQ_Handle *mq;
 
   /**
    * Time the job was originally queued.
@@ -518,6 +497,11 @@ struct GNUNET_FS_QueueEntry
    */
   unsigned int start_times;
 
+  /**
+   * #GNUNET_YES if the job is active now.
+   */
+  int active;
+
 };
 
 
@@ -658,8 +642,8 @@ struct GNUNET_FS_SearchResult
  */
 struct GNUNET_FS_QueueEntry *
 GNUNET_FS_queue_ (struct GNUNET_FS_Handle *h,
-                  GNUNET_FS_QueueStart start,
-                  GNUNET_FS_QueueStop stop,
+                  GNUNET_SCHEDULER_TaskCallback start,
+                  GNUNET_SCHEDULER_TaskCallback stop,
                   void *cls,
                   unsigned int blocks,
                   enum GNUNET_FS_QueuePriority priority);
@@ -1221,7 +1205,7 @@ struct GNUNET_FS_PublishContext
   /**
    * Connection to FS service (only used for LOC URI signing).
    */
-  struct GNUNET_CLIENT_Handle *fs_client;
+  struct GNUNET_CLIENT_Connection *fs_client;
 
   /**
    * Our top-level activity entry (if we are top-level, otherwise NULL).
@@ -1255,7 +1239,7 @@ struct GNUNET_FS_PublishContext
   char *serialization;
 
   /**
-   * Our own client handle for the FS service; only briefly used when
+   * Our own message queue for the FS service; only briefly used when
    * we start to index a file, otherwise NULL.
    */
   struct GNUNET_CLIENT_Connection *client;
@@ -1740,15 +1724,6 @@ enum BlockRequestState
  */
 struct DownloadRequest
 {
-  /**
-   * While pending, we keep all download requests in a doubly-linked list.
-   */
-  struct DownloadRequest *next;
-
-  /**
-   * While pending, we keep all download requests in a doubly-linked list.
-   */
-  struct DownloadRequest *prev;
 
   /**
    * Parent in the CHK-tree.
@@ -1774,7 +1749,7 @@ struct DownloadRequest
   uint64_t offset;
 
   /**
-   * Number of entries in 'children' array.
+   * Number of entries in @e children array.
    */
   unsigned int num_children;
 
@@ -1793,11 +1768,6 @@ struct DownloadRequest
    */
   enum BlockRequestState state;
 
-  /**
-   * #GNUNET_YES if this entry is in the pending list.
-   */
-  int is_pending;
-
 };
 
 
@@ -1838,7 +1808,7 @@ struct GNUNET_FS_DownloadContext
   /**
    * Connection to the FS service.
    */
-  struct GNUNET_CLIENT_Connection *client;
+  struct GNUNET_MQ_Handle *mq;
 
   /**
    * Parent download (used when downloading files
@@ -1917,12 +1887,6 @@ struct GNUNET_FS_DownloadContext
   struct GNUNET_FS_QueueEntry *job_queue;
 
   /**
-   * Non-NULL if we are currently having a request for
-   * transmission pending with the client handle.
-   */
-  struct GNUNET_CLIENT_TransmitHandle *th;
-
-  /**
    * Tree encoder used for the reconstruction.
    */
   struct GNUNET_FS_TreeEncoder *te;
@@ -1940,16 +1904,6 @@ struct GNUNET_FS_DownloadContext
   struct GNUNET_CONTAINER_MultiHashMap *active;
 
   /**
-   * Head of linked list of pending requests.
-   */
-  struct DownloadRequest *pending_head;
-
-  /**
-   * Head of linked list of pending requests.
-   */
-  struct DownloadRequest *pending_tail;
-
-  /**
    * Top-level download request.
    */
   struct DownloadRequest *top_request;
@@ -2029,11 +1983,6 @@ struct GNUNET_FS_DownloadContext
   int has_finished;
 
   /**
-   * Have we started the receive continuation yet?
-   */
-  int in_receive;
-
-  /**
    * Are we ready to issue requests (reconstructions are finished)?
    */
   int issue_requests;
diff --git a/src/fs/fs_download.c b/src/fs/fs_download.c
index d89d70719..98c76882a 100644
--- a/src/fs/fs_download.c
+++ b/src/fs/fs_download.c
@@ -121,7 +121,7 @@ GNUNET_FS_download_make_status_ (struct GNUNET_FS_ProgressInfo *pi,
   pi->value.download.anonymity = dc->anonymity;
   pi->value.download.eta =
       GNUNET_TIME_calculate_eta (dc->start_time, dc->completed, dc->length);
-  pi->value.download.is_active = (NULL == dc->client) ? GNUNET_NO : GNUNET_YES;
+  pi->value.download.is_active = (NULL == dc->mq) ? GNUNET_NO : GNUNET_YES;
   pi->fsh = dc->h;
   if (0 == (dc->options & GNUNET_FS_DOWNLOAD_IS_PROBE))
     dc->client_info = dc->h->upcb (dc->h->upcb_cls, pi);
@@ -131,21 +131,6 @@ GNUNET_FS_download_make_status_ (struct GNUNET_FS_ProgressInfo *pi,
 
 
 /**
- * We're ready to transmit a search request to the
- * file-sharing service.  Do it.  If there is
- * more than one request pending, try to send
- * multiple or request another transmission.
- *
- * @param cls closure
- * @param size number of bytes available in buf
- * @param buf where the callee should write the message
- * @return number of bytes written to buf
- */
-static size_t
-transmit_download_request (void *cls, size_t size, void *buf);
-
-
-/**
  * Closure for iterator processing results.
  */
 struct ProcessResultClosure
@@ -206,10 +191,11 @@ struct ProcessResultClosure
  * @param cls closure (our 'struct ProcessResultClosure')
  * @param key query for the given value / request
  * @param value value in the hash map (a 'struct DownloadRequest')
- * @return GNUNET_YES (we should continue to iterate); unless serious error
+ * @return #GNUNET_YES (we should continue to iterate); unless serious error
  */
 static int
-process_result_with_request (void *cls, const struct GNUNET_HashCode * key,
+process_result_with_request (void *cls,
+                             const struct GNUNET_HashCode * key,
                              void *value);
 
 
@@ -722,6 +708,43 @@ try_top_down_reconstruction (struct GNUNET_FS_DownloadContext *dc,
 
 
 /**
+ * Add entries to the message queue.
+ *
+ * @param cls our download context
+ * @param key unused
+ * @param entry entry of type `struct DownloadRequest`
+ * @return #GNUNET_OK
+ */
+static int
+retry_entry (void *cls,
+             const struct GNUNET_HashCode *key,
+             void *entry)
+{
+  struct GNUNET_FS_DownloadContext *dc = cls;
+  struct DownloadRequest *dr = entry;
+  struct SearchMessage *sm;
+  struct GNUNET_MQ_Envelope *env;
+
+  env = GNUNET_MQ_msg (sm,
+                       GNUNET_MESSAGE_TYPE_FS_START_SEARCH);
+  if (0 != (dc->options & GNUNET_FS_DOWNLOAD_OPTION_LOOPBACK_ONLY))
+    sm->options = htonl (GNUNET_FS_SEARCH_OPTION_LOOPBACK_ONLY);
+  else
+    sm->options = htonl (GNUNET_FS_SEARCH_OPTION_NONE);
+  if (0 == dr->depth)
+    sm->type = htonl (GNUNET_BLOCK_TYPE_FS_DBLOCK);
+  else
+    sm->type = htonl (GNUNET_BLOCK_TYPE_FS_IBLOCK);
+  sm->anonymity_level = htonl (dc->anonymity);
+  sm->target = dc->target;
+  sm->query = dr->chk.query;
+  GNUNET_MQ_send (dc->mq,
+                  env);
+  return GNUNET_OK;
+}
+
+
+/**
  * Schedule the download of the specified block in the tree.
  *
  * @param dc overall download this block belongs to
@@ -763,25 +786,23 @@ schedule_block_download (struct GNUNET_FS_DownloadContext *dc,
   }
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
               "Scheduling download at offset %llu and depth %u for `%s'\n",
-              (unsigned long long) dr->offset, dr->depth,
+              (unsigned long long) dr->offset,
+              dr->depth,
               GNUNET_h2s (&dr->chk.query));
   if (GNUNET_NO !=
-      GNUNET_CONTAINER_multihashmap_contains_value (dc->active, &dr->chk.query,
+      GNUNET_CONTAINER_multihashmap_contains_value (dc->active,
+                                                    &dr->chk.query,
                                                     dr))
     return;                     /* already active */
-  GNUNET_CONTAINER_multihashmap_put (dc->active, &dr->chk.query, dr,
+  GNUNET_CONTAINER_multihashmap_put (dc->active,
+                                     &dr->chk.query,
+                                     dr,
                                      GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE);
-  if (NULL == dc->client)
+  if (NULL == dc->mq)
     return;                     /* download not active */
-  GNUNET_CONTAINER_DLL_insert (dc->pending_head, dc->pending_tail, dr);
-  dr->is_pending = GNUNET_YES;
-  if (NULL == dc->th)
-    dc->th =
-        GNUNET_CLIENT_notify_transmit_ready (dc->client,
-                                             sizeof (struct SearchMessage),
-                                             GNUNET_CONSTANTS_SERVICE_TIMEOUT,
-                                             GNUNET_NO,
-                                             &transmit_download_request, dc);
+  retry_entry (dc,
+               &dr->chk.query,
+               dr);
 }
 
 
@@ -947,13 +968,14 @@ GNUNET_FS_free_download_request_ (struct DownloadRequest *dr)
  * Iterator over entries in the pending requests in the 'active' map for the
  * reply that we just got.
  *
- * @param cls closure (our 'struct ProcessResultClosure')
+ * @param cls closure (our `struct ProcessResultClosure`)
  * @param key query for the given value / request
- * @param value value in the hash map (a 'struct DownloadRequest')
+ * @param value value in the hash map (a `struct DownloadRequest`)
  * @return #GNUNET_YES (we should continue to iterate); unless serious error
  */
 static int
-process_result_with_request (void *cls, const struct GNUNET_HashCode * key,
+process_result_with_request (void *cls,
+                             const struct GNUNET_HashCode *key,
                              void *value)
 {
   struct ProcessResultClosure *prc = cls;
@@ -974,7 +996,9 @@ process_result_with_request (void *cls, const struct GNUNET_HashCode * key,
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
               "Received %u byte block `%s' matching pending request at depth %u and offset %llu/%llu\n",
               (unsigned int) prc->size,
-              GNUNET_h2s (key), dr->depth, (unsigned long long) dr->offset,
+              GNUNET_h2s (key),
+              dr->depth,
+              (unsigned long long) dr->offset,
               (unsigned long long) GNUNET_ntohll (dc->uri->data.
                                                   chk.file_length));
   bs = GNUNET_FS_tree_calculate_block_size (GNUNET_ntohll
@@ -999,15 +1023,17 @@ process_result_with_request (void *cls, const struct GNUNET_HashCode * key,
     goto signal_error;
   }
 
-  (void) GNUNET_CONTAINER_multihashmap_remove (dc->active, &prc->query, dr);
-  if (GNUNET_YES == dr->is_pending)
-  {
-    GNUNET_CONTAINER_DLL_remove (dc->pending_head, dc->pending_tail, dr);
-    dr->is_pending = GNUNET_NO;
-  }
-
-  GNUNET_CRYPTO_hash_to_aes_key (&dr->chk.key, &skey, &iv);
-  if (-1 == GNUNET_CRYPTO_symmetric_decrypt (prc->data, prc->size, &skey, &iv, pt))
+  (void) GNUNET_CONTAINER_multihashmap_remove (dc->active,
+                                               &prc->query,
+                                               dr);
+  GNUNET_CRYPTO_hash_to_aes_key (&dr->chk.key,
+                                 &skey,
+                                 &iv);
+  if (-1 == GNUNET_CRYPTO_symmetric_decrypt (prc->data,
+                                             prc->size,
+                                             &skey,
+                                             &iv,
+                                             pt))
   {
     GNUNET_break (0);
     dc->emsg = GNUNET_strdup (_("internal error decrypting content"));
@@ -1015,7 +1041,8 @@ process_result_with_request (void *cls, const struct GNUNET_HashCode * key,
   }
   off =
       compute_disk_offset (GNUNET_ntohll (dc->uri->data.chk.file_length),
-                           dr->offset, dr->depth);
+                           dr->offset,
+                           dr->depth);
   /* save to disk */
   if ((GNUNET_YES == prc->do_store) &&
       ((NULL != dc->filename) || (is_recursive_download (dc))) &&
@@ -1040,21 +1067,25 @@ process_result_with_request (void *cls, const struct GNUNET_HashCode * key,
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                 "Saving decrypted block to disk at offset %llu\n",
                 (unsigned long long) off);
-    if ((off != GNUNET_DISK_file_seek (fh, off, GNUNET_DISK_SEEK_SET)))
+    if ((off != GNUNET_DISK_file_seek (fh,
+                                       off,
+                                       GNUNET_DISK_SEEK_SET)))
     {
       GNUNET_asprintf (&dc->emsg,
                        _("Failed to seek to offset %llu in file `%s': %s"),
-                       (unsigned long long) off, dc->filename,
+                       (unsigned long long) off,
+                       dc->filename,
                        STRERROR (errno));
       goto signal_error;
     }
     if (prc->size != GNUNET_DISK_file_write (fh, pt, prc->size))
     {
       GNUNET_asprintf (&dc->emsg,
-                       _
-                       ("Failed to write block of %u bytes at offset %llu in file `%s': %s"),
-                       (unsigned int) prc->size, (unsigned long long) off,
-                       dc->filename, STRERROR (errno));
+                       _("Failed to write block of %u bytes at offset %llu in file `%s': %s"),
+                       (unsigned int) prc->size,
+                       (unsigned long long) off,
+                       dc->filename,
+                       STRERROR (errno));
       goto signal_error;
     }
     GNUNET_break (GNUNET_OK == GNUNET_DISK_file_close (fh));
@@ -1193,15 +1224,8 @@ signal_error:
   pi.status = GNUNET_FS_STATUS_DOWNLOAD_ERROR;
   pi.value.download.specifics.error.message = dc->emsg;
   GNUNET_FS_download_make_status_ (&pi, dc);
-  /* abort all pending requests */
-  if (NULL != dc->th)
-  {
-    GNUNET_CLIENT_notify_transmit_ready_cancel (dc->th);
-    dc->th = NULL;
-  }
-  GNUNET_CLIENT_disconnect (dc->client);
-  dc->in_receive = GNUNET_NO;
-  dc->client = NULL;
+  GNUNET_MQ_destroy (dc->mq);
+  dc->mq = NULL;
   GNUNET_FS_free_download_request_ (dc->top_request);
   dc->top_request = NULL;
   GNUNET_CONTAINER_multihashmap_destroy (dc->active);
@@ -1211,49 +1235,24 @@ signal_error:
     GNUNET_FS_dequeue_ (dc->job_queue);
     dc->job_queue = NULL;
   }
-  dc->pending_head = NULL;
-  dc->pending_tail = NULL;
   GNUNET_FS_download_sync_ (dc);
   return GNUNET_NO;
 }
 
 
 /**
- * Process a download result.
+ * Type of a function to call when we check the PUT message
+ * from the service.
  *
- * @param dc our download context
- * @param type type of the result
- * @param respect_offered how much respect did we offer to get this reply?
- * @param num_transmissions how often did we transmit the query?
- * @param last_transmission when was this block requested the last time? (FOREVER if unknown/not applicable)
- * @param data the (encrypted) response
- * @param size size of data
+ * @param cls closure
+ * @param msg message received
  */
-static void
-process_result (struct GNUNET_FS_DownloadContext *dc,
-                enum GNUNET_BLOCK_Type type,
-                uint32_t respect_offered,
-                uint32_t num_transmissions,
-                struct GNUNET_TIME_Absolute last_transmission,
-                const void *data, size_t size)
+static int
+check_put (void *cls,
+           const struct ClientPutMessage *cm)
 {
-  struct ProcessResultClosure prc;
-
-  prc.dc = dc;
-  prc.data = data;
-  prc.last_transmission = last_transmission;
-  prc.size = size;
-  prc.type = type;
-  prc.do_store = GNUNET_YES;
-  prc.respect_offered = respect_offered;
-  prc.num_transmissions = num_transmissions;
-  GNUNET_CRYPTO_hash (data, size, &prc.query);
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              "Received result for query `%s' from `%s'-service\n",
-              GNUNET_h2s (&prc.query), "FS");
-  GNUNET_CONTAINER_multihashmap_get_multiple (dc->active, &prc.query,
-                                              &process_result_with_request,
-                                              &prc);
+  /* any varsize length is OK */
+  return GNUNET_OK;
 }
 
 
@@ -1262,109 +1261,59 @@ process_result (struct GNUNET_FS_DownloadContext *dc,
  * from the service.
  *
  * @param cls closure
- * @param msg message received, NULL on timeout or fatal error
+ * @param msg message received
  */
 static void
-receive_results (void *cls, const struct GNUNET_MessageHeader *msg)
+handle_put (void *cls,
+            const struct ClientPutMessage *cm)
 {
   struct GNUNET_FS_DownloadContext *dc = cls;
-  const struct ClientPutMessage *cm;
-  uint16_t msize;
+  uint16_t msize = ntohs (cm->header.size) - sizeof (*cm);
+  struct ProcessResultClosure prc;
 
-  if ((NULL == msg) || (ntohs (msg->type) != GNUNET_MESSAGE_TYPE_FS_PUT) ||
-      (sizeof (struct ClientPutMessage) > ntohs (msg->size)))
-  {
-    GNUNET_break (NULL == msg);
-    try_reconnect (dc);
-    return;
-  }
-  msize = ntohs (msg->size);
-  cm = (const struct ClientPutMessage *) msg;
-  process_result (dc, ntohl (cm->type),
-                  ntohl (cm->respect_offered),
-                  ntohl (cm->num_transmissions),
-                  GNUNET_TIME_absolute_ntoh (cm->last_transmission), &cm[1],
-                  msize - sizeof (struct ClientPutMessage));
-  if (NULL == dc->client)
-    return;                     /* fatal error */
-  /* continue receiving */
-  GNUNET_CLIENT_receive (dc->client, &receive_results, dc,
-                         GNUNET_TIME_UNIT_FOREVER_REL);
+  prc.dc = dc;
+  prc.data = &cm[1];
+  prc.last_transmission = GNUNET_TIME_absolute_ntoh (cm->last_transmission);
+  prc.size = msize;
+  prc.type = ntohl (cm->type);
+  prc.do_store = GNUNET_YES;
+  prc.respect_offered = ntohl (cm->respect_offered);
+  prc.num_transmissions = ntohl (cm->num_transmissions);
+  GNUNET_CRYPTO_hash (prc.data,
+                      msize,
+                      &prc.query);
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Received result for query `%s' from FS service\n",
+              GNUNET_h2s (&prc.query));
+  GNUNET_CONTAINER_multihashmap_get_multiple (dc->active,
+                                              &prc.query,
+                                              &process_result_with_request,
+                                              &prc);
 }
 
 
 /**
- * We're ready to transmit a search request to the
- * file-sharing service.  Do it.  If there is
- * more than one request pending, try to send
- * multiple or request another transmission.
+ * Generic error handler, called with the appropriate error code and
+ * the same closure specified at the creation of the message queue.
+ * Not every message queue implementation supports an error handler.
  *
- * @param cls closure
- * @param size number of bytes available in buf
- * @param buf where the callee should write the message
- * @return number of bytes written to buf
+ * @param cls closure with the `struct GNUNET_FS_DownloadContext *`
+ * @param error error code
  */
-static size_t
-transmit_download_request (void *cls, size_t size, void *buf)
+static void
+download_mq_error_handler (void *cls,
+                           enum GNUNET_MQ_Error error)
 {
   struct GNUNET_FS_DownloadContext *dc = cls;
-  size_t msize;
-  struct SearchMessage *sm;
-  struct DownloadRequest *dr;
 
-  dc->th = NULL;
-  if (NULL == buf)
+  if (NULL != dc->mq)
   {
-    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-                "Transmitting download request failed, trying to reconnect\n");
-    try_reconnect (dc);
-    return 0;
+    GNUNET_MQ_destroy (dc->mq);
+    dc->mq = NULL;
   }
-  GNUNET_assert (size >= sizeof (struct SearchMessage));
-  msize = 0;
-  sm = buf;
-  while ((NULL != (dr = dc->pending_head)) &&
-         (size >= msize + sizeof (struct SearchMessage)))
-  {
-    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-                "Transmitting download request for `%s' to `%s'-service\n",
-                GNUNET_h2s (&dr->chk.query), "FS");
-    memset (sm, 0, sizeof (struct SearchMessage));
-    sm->header.size = htons (sizeof (struct SearchMessage));
-    sm->header.type = htons (GNUNET_MESSAGE_TYPE_FS_START_SEARCH);
-    if (0 != (dc->options & GNUNET_FS_DOWNLOAD_OPTION_LOOPBACK_ONLY))
-      sm->options = htonl (GNUNET_FS_SEARCH_OPTION_LOOPBACK_ONLY);
-    else
-      sm->options = htonl (GNUNET_FS_SEARCH_OPTION_NONE);
-    if (0 == dr->depth)
-      sm->type = htonl (GNUNET_BLOCK_TYPE_FS_DBLOCK);
-    else
-      sm->type = htonl (GNUNET_BLOCK_TYPE_FS_IBLOCK);
-    sm->anonymity_level = htonl (dc->anonymity);
-    sm->target = dc->target;
-    sm->query = dr->chk.query;
-    GNUNET_CONTAINER_DLL_remove (dc->pending_head, dc->pending_tail, dr);
-    dr->is_pending = GNUNET_NO;
-    msize += sizeof (struct SearchMessage);
-    sm++;
-  }
-  if (NULL != dc->pending_head)
-  {
-    dc->th =
-        GNUNET_CLIENT_notify_transmit_ready (dc->client,
-                                             sizeof (struct SearchMessage),
-                                             GNUNET_CONSTANTS_SERVICE_TIMEOUT,
-                                             GNUNET_NO,
-                                             &transmit_download_request, dc);
-    GNUNET_assert (NULL != dc->th);
-  }
-  if (GNUNET_NO == dc->in_receive)
-  {
-    dc->in_receive = GNUNET_YES;
-    GNUNET_CLIENT_receive (dc->client, &receive_results, dc,
-                           GNUNET_TIME_UNIT_FOREVER_REL);
-  }
-  return msize;
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Transmitting download request failed, trying to reconnect\n");
+  try_reconnect (dc);
 }
 
 
@@ -1376,51 +1325,31 @@ transmit_download_request (void *cls, size_t size, void *buf)
 static void
 do_reconnect (void *cls)
 {
+  GNUNET_MQ_hd_var_size (put,
+                         GNUNET_MESSAGE_TYPE_FS_PUT,
+                         struct ClientPutMessage);
   struct GNUNET_FS_DownloadContext *dc = cls;
-  struct GNUNET_CLIENT_Connection *client;
+  struct GNUNET_MQ_MessageHandler handlers[] = {
+    make_put_handler (dc),
+    GNUNET_MQ_handler_end ()
+  };
 
   dc->task = NULL;
-  client = GNUNET_CLIENT_connect ("fs", dc->h->cfg);
-  if (NULL == client)
+  dc->mq = GNUNET_CLIENT_connecT (dc->h->cfg,
+                                  "fs",
+                                  handlers,
+                                  &download_mq_error_handler,
+                                  dc);
+  if (NULL == dc->mq)
   {
     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                 "Connecting to `%s'-service failed, will try again.\n", "FS");
     try_reconnect (dc);
     return;
   }
-  dc->client = client;
-  if (NULL != dc->pending_head)
-  {
-    dc->th =
-        GNUNET_CLIENT_notify_transmit_ready (client,
-                                             sizeof (struct SearchMessage),
-                                             GNUNET_CONSTANTS_SERVICE_TIMEOUT,
-                                             GNUNET_NO,
-                                             &transmit_download_request, dc);
-    GNUNET_assert (NULL != dc->th);
-  }
-}
-
-
-/**
- * Add entries to the pending list.
- *
- * @param cls our download context
- * @param key unused
- * @param entry entry of type "struct DownloadRequest"
- * @return GNUNET_OK
- */
-static int
-retry_entry (void *cls, const struct GNUNET_HashCode * key, void *entry)
-{
-  struct GNUNET_FS_DownloadContext *dc = cls;
-  struct DownloadRequest *dr = entry;
-
-  dr->next = NULL;
-  dr->prev = NULL;
-  GNUNET_CONTAINER_DLL_insert (dc->pending_head, dc->pending_tail, dr);
-  dr->is_pending = GNUNET_YES;
-  return GNUNET_OK;
+  GNUNET_CONTAINER_multihashmap_iterate (dc->active,
+                                         &retry_entry,
+                                         dc);
 }
 
 
@@ -1435,30 +1364,22 @@ static void
 try_reconnect (struct GNUNET_FS_DownloadContext *dc)
 {
 
-  if (NULL != dc->client)
+  if (NULL != dc->mq)
   {
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                 "Moving all requests back to pending list\n");
-    if (NULL != dc->th)
-    {
-      GNUNET_CLIENT_notify_transmit_ready_cancel (dc->th);
-      dc->th = NULL;
-    }
-    /* full reset of the pending list */
-    dc->pending_head = NULL;
-    dc->pending_tail = NULL;
-    GNUNET_CONTAINER_multihashmap_iterate (dc->active, &retry_entry, dc);
-    GNUNET_CLIENT_disconnect (dc->client);
-    dc->in_receive = GNUNET_NO;
-    dc->client = NULL;
+    GNUNET_MQ_destroy (dc->mq);
+    dc->mq = NULL;
   }
   if (0 == dc->reconnect_backoff.rel_value_us)
     dc->reconnect_backoff = GNUNET_TIME_UNIT_MILLISECONDS;
   else
     dc->reconnect_backoff = GNUNET_TIME_STD_BACKOFF (dc->reconnect_backoff);
 
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Will try to reconnect in %s\n",
-              GNUNET_STRINGS_relative_time_to_string (dc->reconnect_backoff, GNUNET_YES));
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Will try to reconnect in %s\n",
+              GNUNET_STRINGS_relative_time_to_string (dc->reconnect_backoff,
+                                                      GNUNET_YES));
   dc->task =
     GNUNET_SCHEDULER_add_delayed (dc->reconnect_backoff,
                                   &do_reconnect,
@@ -1470,37 +1391,23 @@ try_reconnect (struct GNUNET_FS_DownloadContext *dc)
  * We're allowed to ask the FS service for our blocks.  Start the download.
  *
  * @param cls the 'struct GNUNET_FS_DownloadContext'
- * @param client handle to use for communcation with FS (we must destroy it!)
+ * @param mq handle to use for communcation with FS (we must destroy it!)
  */
 static void
-activate_fs_download (void *cls, struct GNUNET_CLIENT_Connection *client)
+activate_fs_download (void *cls)
 {
   struct GNUNET_FS_DownloadContext *dc = cls;
   struct GNUNET_FS_ProgressInfo pi;
 
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Download activated\n");
-  GNUNET_assert (NULL != client);
-  GNUNET_assert (NULL == dc->client);
-  GNUNET_assert (NULL == dc->th);
+  GNUNET_assert (NULL == dc->mq);
   GNUNET_assert (NULL != dc->active);
-  dc->client = client;
+  do_reconnect (dc);
+  if (NULL != dc->mq)
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Download activated\n");
   pi.status = GNUNET_FS_STATUS_DOWNLOAD_ACTIVE;
-  GNUNET_FS_download_make_status_ (&pi, dc);
-  dc->pending_head = NULL;
-  dc->pending_tail = NULL;
-  GNUNET_CONTAINER_multihashmap_iterate (dc->active, &retry_entry, dc);
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              "Asking for transmission to FS service\n");
-  if (NULL != dc->pending_head)
-  {
-    dc->th =
-        GNUNET_CLIENT_notify_transmit_ready (dc->client,
-                                             sizeof (struct SearchMessage),
-                                             GNUNET_CONSTANTS_SERVICE_TIMEOUT,
-                                             GNUNET_NO,
-                                             &transmit_download_request, dc);
-    GNUNET_assert (NULL != dc->th);
-  }
+  GNUNET_FS_download_make_status_ (&pi,
+                                   dc);
 }
 
 
@@ -1515,22 +1422,16 @@ deactivate_fs_download (void *cls)
   struct GNUNET_FS_DownloadContext *dc = cls;
   struct GNUNET_FS_ProgressInfo pi;
 
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Download deactivated\n");
-  if (NULL != dc->th)
-  {
-    GNUNET_CLIENT_notify_transmit_ready_cancel (dc->th);
-    dc->th = NULL;
-  }
-  if (NULL != dc->client)
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Download deactivated\n");
+  if (NULL != dc->mq)
   {
-    GNUNET_CLIENT_disconnect (dc->client);
-    dc->in_receive = GNUNET_NO;
-    dc->client = NULL;
+    GNUNET_MQ_destroy (dc->mq);
+    dc->mq = NULL;
   }
-  dc->pending_head = NULL;
-  dc->pending_tail = NULL;
   pi.status = GNUNET_FS_STATUS_DOWNLOAD_INACTIVE;
-  GNUNET_FS_download_make_status_ (&pi, dc);
+  GNUNET_FS_download_make_status_ (&pi,
+                                   dc);
 }
 
 
@@ -1557,7 +1458,8 @@ static struct DownloadRequest *
 create_download_request (struct DownloadRequest *parent,
                          unsigned int chk_idx,
                          unsigned int depth,
-                         uint64_t dr_offset, uint64_t file_start_offset,
+                         uint64_t dr_offset,
+                         uint64_t file_start_offset,
                          uint64_t desired_length)
 {
   struct DownloadRequest *dr;
@@ -1746,13 +1648,9 @@ reconstruct_cb (void *cls, const struct ContentHashKey *chk, uint64_t offset,
       /* block matches, hence tree below matches;
        * this request is done! */
       dr->state = BRS_DOWNLOAD_UP;
-      (void) GNUNET_CONTAINER_multihashmap_remove (dc->active, &dr->chk.query, dr);
-      if (GNUNET_YES == dr->is_pending)
-      {
-        GNUNET_break (0); /* how did we get here? */
-        GNUNET_CONTAINER_DLL_remove (dc->pending_head, dc->pending_tail, dr);
-        dr->is_pending = GNUNET_NO;
-      }
+      (void) GNUNET_CONTAINER_multihashmap_remove (dc->active,
+                                                   &dr->chk.query,
+                                                   dr);
       /* calculate how many bytes of payload this block
        * corresponds to */
       blen = GNUNET_FS_tree_compute_tree_size (dr->depth);
@@ -1860,7 +1758,8 @@ GNUNET_FS_download_start_task_ (void *cls)
   struct GNUNET_FS_ProgressInfo pi;
   struct GNUNET_DISK_FileHandle *fh;
 
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Start task running...\n");
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Start task running...\n");
   dc->task = NULL;
   if (0 == dc->length)
   {
@@ -1978,8 +1877,10 @@ GNUNET_FS_download_start_task_ (void *cls)
     dc->te =
       GNUNET_FS_tree_encoder_create (dc->h,
                                      GNUNET_FS_uri_chk_get_file_size (dc->uri),
-                                     dc, &fh_reader,
-                                     &reconstruct_cb, NULL,
+                                     dc,
+                                     &fh_reader,
+                                     &reconstruct_cb,
+                                     NULL,
                                      &reconstruct_cont);
     dc->task = GNUNET_SCHEDULER_add_now (&get_next_block, dc);
   }
@@ -2079,9 +1980,13 @@ struct GNUNET_FS_DownloadContext *
 create_download_context (struct GNUNET_FS_Handle *h,
                          const struct GNUNET_FS_Uri *uri,
                          const struct GNUNET_CONTAINER_MetaData *meta,
-                         const char *filename, const char *tempname,
-                         uint64_t offset, uint64_t length, uint32_t anonymity,
-                         enum GNUNET_FS_DownloadOptions options, void *cctx)
+                         const char *filename,
+                         const char *tempname,
+                         uint64_t offset,
+                         uint64_t length,
+                         uint32_t anonymity,
+                         enum GNUNET_FS_DownloadOptions options,
+                         void *cctx)
 {
   struct GNUNET_FS_DownloadContext *dc;
 
@@ -2132,7 +2037,8 @@ create_download_context (struct GNUNET_FS_Handle *h,
               filename,
               (unsigned long long) length,
               dc->treedepth);
-  dc->task = GNUNET_SCHEDULER_add_now (&GNUNET_FS_download_start_task_, dc);
+  dc->task = GNUNET_SCHEDULER_add_now (&GNUNET_FS_download_start_task_,
+                                       dc);
   return dc;
 }
 
@@ -2290,6 +2196,8 @@ GNUNET_FS_download_start_downloading_ (struct GNUNET_FS_DownloadContext *dc)
 {
   if (dc->completed == dc->length)
     return;
+  if (NULL != dc->mq)
+    return; /* already running */
   GNUNET_assert (NULL == dc->job_queue);
   GNUNET_assert (NULL != dc->active);
   dc->job_queue =
diff --git a/src/fs/fs_search.c b/src/fs/fs_search.c
index f3221ac76..9a1b822e1 100644
--- a/src/fs/fs_search.c
+++ b/src/fs/fs_search.c
@@ -368,7 +368,7 @@ probe_ping_task_cb (void *cls)
   struct GNUNET_FS_SearchResult *sr;
 
   for (sr = h->probes_head; NULL != sr; sr = sr->next)
-    if (NULL != sr->probe_ctx->client)
+    if (NULL != sr->probe_ctx->mq)
       signal_probe_result (sr);
   h->probe_ping_task
     = GNUNET_SCHEDULER_add_delayed (GNUNET_FS_PROBE_UPDATE_FREQUENCY,
diff --git a/src/fs/fs_unindex.c b/src/fs/fs_unindex.c
index e614fbe03..f43725a59 100644
--- a/src/fs/fs_unindex.c
+++ b/src/fs/fs_unindex.c
@@ -110,8 +110,11 @@ GNUNET_FS_unindex_make_status_ (struct GNUNET_FS_ProgressInfo *pi,
  * @param depth depth of the block in the tree, 0 for DBLOCK
  */
 static void
-unindex_progress (void *cls, uint64_t offset, const void *pt_block,
-                  size_t pt_size, unsigned int depth)
+unindex_progress (void *cls,
+                  uint64_t offset,
+                  const void *pt_block,
+                  size_t pt_size,
+                  unsigned int depth)
 {
   struct GNUNET_FS_UnindexContext *uc = cls;
   struct GNUNET_FS_ProgressInfo pi;