Merge branch 'master' of ssh://gnunet.org/gnunet
[oweals/gnunet.git] / src / fs / fs_search.c
index a9c9389c4199a11c86ed25e0b5d69d66ac906a34..3cbf2afefdcc0ec3f5f388735af00bec9d39d2c2 100644 (file)
@@ -1,6 +1,6 @@
 /*
      This file is part of GNUnet.
-     (C) 2001-2014 Christian Grothoff (and other contributing authors)
+     Copyright (C) 2001-2014 GNUnet e.V.
 
      GNUnet is free software; you can redistribute it and/or modify
      it under the terms of the GNU General Public License as published
@@ -15,7 +15,7 @@
      You should have received a copy of the GNU General Public License
      along with GNUnet; see the file COPYING.  If not, write to the
      Free Software Foundation, Inc., 59 Tem ple Place - Suite 330,
-     Boston, MA 02111-1307, USA.
+     Boston, MA 02110-1301, USA.
 */
 /**
  * @file fs/fs_search.c
@@ -171,7 +171,9 @@ struct GetResultContext
  * @return #GNUNET_OK
  */
 static int
-get_result_present (void *cls, const struct GNUNET_HashCode * key, void *value)
+get_result_present (void *cls,
+                    const struct GNUNET_HashCode *key,
+                    void *value)
 {
   struct GetResultContext *grc = cls;
   struct GNUNET_FS_SearchResult *sr = value;
@@ -213,22 +215,17 @@ signal_probe_result (struct GNUNET_FS_SearchResult *sr)
  * Handle the case where we have failed to receive a response for our probe.
  *
  * @param cls our `struct GNUNET_FS_SearchResult *`
- * @param tc scheduler context
  */
 static void
-probe_failure_handler (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
+probe_failure_handler (void *cls)
 {
   struct GNUNET_FS_SearchResult *sr = cls;
 
-  sr->probe_cancel_task = GNUNET_SCHEDULER_NO_TASK;
+  sr->probe_cancel_task = NULL;
   sr->availability_trials++;
   GNUNET_FS_download_stop (sr->probe_ctx, GNUNET_YES);
   sr->probe_ctx = NULL;
-  if (GNUNET_SCHEDULER_NO_TASK != sr->probe_ping_task)
-  {
-    GNUNET_SCHEDULER_cancel (sr->probe_ping_task);
-    sr->probe_ping_task = GNUNET_SCHEDULER_NO_TASK;
-  }
+  GNUNET_FS_stop_probe_ping_task_ (sr);
   GNUNET_FS_search_result_sync_ (sr);
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Probe #%u for search result %p failed\n",
@@ -242,23 +239,18 @@ probe_failure_handler (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
  * Handle the case where we have gotten a response for our probe.
  *
  * @param cls our `struct GNUNET_FS_SearchResult *`
- * @param tc scheduler context
  */
 static void
-probe_success_handler (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
+probe_success_handler (void *cls)
 {
   struct GNUNET_FS_SearchResult *sr = cls;
 
-  sr->probe_cancel_task = GNUNET_SCHEDULER_NO_TASK;
+  sr->probe_cancel_task = NULL;
   sr->availability_trials++;
   sr->availability_success++;
   GNUNET_FS_download_stop (sr->probe_ctx, GNUNET_YES);
   sr->probe_ctx = NULL;
-  if (GNUNET_SCHEDULER_NO_TASK != sr->probe_ping_task)
-  {
-    GNUNET_SCHEDULER_cancel (sr->probe_ping_task);
-    sr->probe_ping_task = GNUNET_SCHEDULER_NO_TASK;
-  }
+  GNUNET_FS_stop_probe_ping_task_ (sr);
   GNUNET_FS_search_result_sync_ (sr);
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Probe #%u for search result %p succeeded\n",
@@ -307,34 +299,34 @@ GNUNET_FS_search_probe_progress_ (void *cls,
     /* ignore */
     break;
   case GNUNET_FS_STATUS_DOWNLOAD_ERROR:
-    if (GNUNET_SCHEDULER_NO_TASK != sr->probe_cancel_task)
+    if (NULL != sr->probe_cancel_task)
     {
       GNUNET_SCHEDULER_cancel (sr->probe_cancel_task);
-      sr->probe_cancel_task = GNUNET_SCHEDULER_NO_TASK;
+      sr->probe_cancel_task = NULL;
     }
     sr->probe_cancel_task =
         GNUNET_SCHEDULER_add_delayed (sr->remaining_probe_time,
                                       &probe_failure_handler, sr);
     break;
   case GNUNET_FS_STATUS_DOWNLOAD_COMPLETED:
-    if (GNUNET_SCHEDULER_NO_TASK != sr->probe_cancel_task)
+    if (NULL != sr->probe_cancel_task)
     {
       GNUNET_SCHEDULER_cancel (sr->probe_cancel_task);
-      sr->probe_cancel_task = GNUNET_SCHEDULER_NO_TASK;
+      sr->probe_cancel_task = NULL;
     }
     sr->probe_cancel_task =
         GNUNET_SCHEDULER_add_now (&probe_success_handler, sr);
     break;
   case GNUNET_FS_STATUS_DOWNLOAD_STOPPED:
-    if (GNUNET_SCHEDULER_NO_TASK != sr->probe_cancel_task)
+    if (NULL != sr->probe_cancel_task)
     {
       GNUNET_SCHEDULER_cancel (sr->probe_cancel_task);
-      sr->probe_cancel_task = GNUNET_SCHEDULER_NO_TASK;
+      sr->probe_cancel_task = NULL;
     }
     sr = NULL;
     break;
   case GNUNET_FS_STATUS_DOWNLOAD_ACTIVE:
-    if (GNUNET_SCHEDULER_NO_TASK == sr->probe_cancel_task)
+    if (NULL == sr->probe_cancel_task)
     {
       sr->probe_active_time = GNUNET_TIME_absolute_get ();
       sr->probe_cancel_task =
@@ -343,10 +335,10 @@ GNUNET_FS_search_probe_progress_ (void *cls,
     }
     break;
   case GNUNET_FS_STATUS_DOWNLOAD_INACTIVE:
-    if (GNUNET_SCHEDULER_NO_TASK != sr->probe_cancel_task)
+    if (NULL != sr->probe_cancel_task)
     {
       GNUNET_SCHEDULER_cancel (sr->probe_cancel_task);
-      sr->probe_cancel_task = GNUNET_SCHEDULER_NO_TASK;
+      sr->probe_cancel_task = NULL;
     }
     dur = GNUNET_TIME_absolute_get_duration (sr->probe_active_time);
     sr->remaining_probe_time =
@@ -367,20 +359,62 @@ GNUNET_FS_search_probe_progress_ (void *cls,
 /**
  * Task run periodically to remind clients that a probe is active.
  *
- * @param cls the 'struct GNUNET_FS_SearchResult' that we are probing for
- * @param tc scheduler context
+ * @param cls the `struct GNUNET_FS_SearchResult` that we are probing for
  */
 static void
-probe_ping_task (void *cls,
-                const struct GNUNET_SCHEDULER_TaskContext *tc)
+probe_ping_task_cb (void *cls)
 {
-  struct GNUNET_FS_SearchResult *sr = cls;
+  struct GNUNET_FS_Handle *h = cls;
+  struct GNUNET_FS_SearchResult *sr;
 
-  signal_probe_result (sr);
-  sr->probe_ping_task
+  for (sr = h->probes_head; NULL != sr; sr = sr->next)
+    if (NULL != sr->probe_ctx->mq)
+      signal_probe_result (sr);
+  h->probe_ping_task
     = GNUNET_SCHEDULER_add_delayed (GNUNET_FS_PROBE_UPDATE_FREQUENCY,
-                                   &probe_ping_task,
-                                   sr);
+                                   &probe_ping_task_cb,
+                                   h);
+}
+
+
+/**
+ * Start the ping task for this search result.
+ *
+ * @param sr result to start pinging for.
+ */
+static void
+start_probe_ping_task (struct GNUNET_FS_SearchResult *sr)
+{
+  struct GNUNET_FS_Handle *h = sr->h;
+
+  GNUNET_CONTAINER_DLL_insert (h->probes_head,
+                               h->probes_tail,
+                               sr);
+  if (NULL == h->probe_ping_task)
+    h->probe_ping_task
+      = GNUNET_SCHEDULER_add_now (&probe_ping_task_cb,
+                                  h);
+}
+
+
+/**
+ * Stop the ping task for this search result.
+ *
+ * @param sr result to start pinging for.
+ */
+void
+GNUNET_FS_stop_probe_ping_task_ (struct GNUNET_FS_SearchResult *sr)
+{
+  struct GNUNET_FS_Handle *h = sr->h;
+
+  GNUNET_CONTAINER_DLL_remove (h->probes_head,
+                               h->probes_tail,
+                               sr);
+  if (NULL == h->probes_head)
+  {
+    GNUNET_SCHEDULER_cancel (h->probe_ping_task);
+    h->probe_ping_task = NULL;
+  }
 }
 
 
@@ -424,16 +458,14 @@ GNUNET_FS_search_start_probe_ (struct GNUNET_FS_SearchResult *sr)
              (unsigned long long) off,
              sr);
   sr->remaining_probe_time =
-      GNUNET_TIME_relative_multiply (sr->h->avg_block_latency,
-                                     2 * (1 + sr->availability_trials));
+      GNUNET_TIME_relative_saturating_multiply (sr->h->avg_block_latency,
+                                                2 * (1 + sr->availability_trials));
   sr->probe_ctx =
       GNUNET_FS_download_start (sr->h, sr->uri, sr->meta, NULL, NULL, off,
                                 len, sr->anonymity,
                                 GNUNET_FS_DOWNLOAD_NO_TEMPORARIES |
                                 GNUNET_FS_DOWNLOAD_IS_PROBE, sr, NULL);
-  sr->probe_ping_task
-    = GNUNET_SCHEDULER_add_now (&probe_ping_task,
-                               sr);
+  start_probe_ping_task (sr);
 }
 
 
@@ -480,16 +512,12 @@ GNUNET_FS_search_stop_probe_ (struct GNUNET_FS_SearchResult *sr)
   {
     GNUNET_FS_download_stop (sr->probe_ctx, GNUNET_YES);
     sr->probe_ctx = NULL;
+    GNUNET_FS_stop_probe_ping_task_ (sr);
   }
-  if (GNUNET_SCHEDULER_NO_TASK != sr->probe_ping_task)
-  {
-    GNUNET_SCHEDULER_cancel (sr->probe_ping_task);
-    sr->probe_ping_task = GNUNET_SCHEDULER_NO_TASK;
-  }
-  if (GNUNET_SCHEDULER_NO_TASK != sr->probe_cancel_task)
+  if (NULL != sr->probe_cancel_task)
   {
     GNUNET_SCHEDULER_cancel (sr->probe_cancel_task);
-    sr->probe_cancel_task = GNUNET_SCHEDULER_NO_TASK;
+    sr->probe_cancel_task = NULL;
   }
 }
 
@@ -623,9 +651,12 @@ process_ksk_result (struct GNUNET_FS_SearchContext *sc,
  * @return context that can be used to control the search
  */
 static struct GNUNET_FS_SearchContext *
-search_start (struct GNUNET_FS_Handle *h, const struct GNUNET_FS_Uri *uri,
-              uint32_t anonymity, enum GNUNET_FS_SearchOptions options,
-              void *cctx, struct GNUNET_FS_SearchResult *psearch);
+search_start (struct GNUNET_FS_Handle *h,
+              const struct GNUNET_FS_Uri *uri,
+              uint32_t anonymity,
+              enum GNUNET_FS_SearchOptions options,
+              void *cctx,
+              struct GNUNET_FS_SearchResult *psearch);
 
 
 /**
@@ -861,22 +892,46 @@ process_sblock (struct GNUNET_FS_SearchContext *sc,
 
 
 /**
- * Process a search result.
+ * Shutdown any existing connection to the FS
+ * service and try to establish a fresh one
+ * (and then re-transmit our search request).
  *
- * @param sc our search context
- * @param type type of the result
- * @param expiration when it will expire
- * @param data the (encrypted) response
- * @param size size of @a data
+ * @param sc the search to reconnec
  */
 static void
-process_result (struct GNUNET_FS_SearchContext *sc,
-               enum GNUNET_BLOCK_Type type,
-                struct GNUNET_TIME_Absolute expiration,
-               const void *data,
-                size_t size)
+try_reconnect (struct GNUNET_FS_SearchContext *sc);
+
+
+/**
+ * We check a result message from the service.
+ *
+ * @param cls closure
+ * @param msg result message received
+ */
+static int
+check_result (void *cls,
+              const struct ClientPutMessage *cm)
+{
+  /* payload of any variable size is OK */
+  return GNUNET_OK;
+}
+
+
+/**
+ * We process a search result from the service.
+ *
+ * @param cls closure
+ * @param msg result message received
+ */
+static void
+handle_result (void *cls,
+               const struct ClientPutMessage *cm)
 {
-  if (GNUNET_TIME_absolute_get_duration (expiration).rel_value_us > 0)
+  struct GNUNET_FS_SearchContext *sc = cls;
+  uint16_t msize = ntohs (cm->header.size) - sizeof (*cm);
+  enum GNUNET_BLOCK_Type type = ntohl (cm->type);
+
+  if (GNUNET_TIME_absolute_get_duration (GNUNET_TIME_absolute_ntoh (cm->expiration)).rel_value_us > 0)
   {
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                 "Result received has already expired.\n");
@@ -886,9 +941,13 @@ process_result (struct GNUNET_FS_SearchContext *sc,
   {
   case GNUNET_BLOCK_TYPE_FS_UBLOCK:
     if (GNUNET_FS_URI_SKS == sc->uri->type)
-      process_sblock (sc, data, size);
+      process_sblock (sc,
+                      (const struct UBlock *) &cm[1],
+                      msize);
     else
-      process_kblock (sc, data, size);
+      process_kblock (sc,
+                      (const struct UBlock *) &cm[1],
+                      msize);
     break;
   case GNUNET_BLOCK_TYPE_ANY:
     GNUNET_break (0);
@@ -904,56 +963,13 @@ process_result (struct GNUNET_FS_SearchContext *sc,
     break;
   default:
     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
-                _("Got result with unknown block type `%d', ignoring"), type);
+                _("Got result with unknown block type `%d', ignoring"),
+                type);
     break;
   }
 }
 
 
-/**
- * Shutdown any existing connection to the FS
- * service and try to establish a fresh one
- * (and then re-transmit our search request).
- *
- * @param sc the search to reconnec
- */
-static void
-try_reconnect (struct GNUNET_FS_SearchContext *sc);
-
-
-/**
- * Type of a function to call when we receive a message
- * from the service.
- *
- * @param cls closure
- * @param msg message received, NULL on timeout or fatal error
- */
-static void
-receive_results (void *cls, const struct GNUNET_MessageHeader *msg)
-{
-  struct GNUNET_FS_SearchContext *sc = cls;
-  const struct ClientPutMessage *cm;
-  uint16_t msize;
-
-  if ((NULL == msg) || (ntohs (msg->type) != GNUNET_MESSAGE_TYPE_FS_PUT) ||
-      (ntohs (msg->size) <= sizeof (struct ClientPutMessage)))
-  {
-    try_reconnect (sc);
-    return;
-  }
-  msize = ntohs (msg->size);
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              "Receiving %u bytes of result from fs service\n", msize);
-  cm = (const struct ClientPutMessage *) msg;
-  process_result (sc, ntohl (cm->type),
-                  GNUNET_TIME_absolute_ntoh (cm->expiration), &cm[1],
-                  msize - sizeof (struct ClientPutMessage));
-  /* continue receiving */
-  GNUNET_CLIENT_receive (sc->client, &receive_results, sc,
-                         GNUNET_TIME_UNIT_FOREVER_REL);
-}
-
-
 /**
  * Schedule the transmission of the (next) search request
  * to the service.
@@ -965,7 +981,7 @@ schedule_transmit_search_request (struct GNUNET_FS_SearchContext *sc);
 
 
 /**
- * Closure for 'build_result_set'.
+ * Closure for #build_result_set().
  */
 struct MessageBuilderContext
 {
@@ -1023,7 +1039,6 @@ build_result_set (void *cls,
   }
   if (0 == mbc->put_cnt)
     return GNUNET_SYSERR;
-  mbc->sc->search_request_map_offset++;
   mbc->xoff[--mbc->put_cnt] = *key;
 
   return GNUNET_OK;
@@ -1056,153 +1071,157 @@ find_result_set (void *cls,
 
 
 /**
- * We're ready to transmit the search request to the file-sharing
- * service.  Do it.  If the request is too large to fit into a single
- * message, transmit in increments.
+ * Schedule the transmission of the (next) search request
+ * to the service.
  *
- * @param cls closure
- * @param size number of bytes available in @a buf
- * @param buf where the callee should write the message
- * @return number of bytes written to @a buf
+ * @param sc context for the search
  */
-static size_t
-transmit_search_request (void *cls, size_t size, void *buf)
+static void
+schedule_transmit_search_request (struct GNUNET_FS_SearchContext *sc)
 {
-  struct GNUNET_FS_SearchContext *sc = cls;
   struct MessageBuilderContext mbc;
-  size_t msize;
+  struct GNUNET_MQ_Envelope *env;
   struct SearchMessage *sm;
   struct GNUNET_CRYPTO_EcdsaPublicKey dpub;
   unsigned int total_seen_results; /* total number of result hashes to send */
-  unsigned int message_size_limit;
   uint32_t options;
+  unsigned int left;
+  unsigned int todo;
+  unsigned int fit;
+  int first_call;
+  unsigned int search_request_map_offset;
+  unsigned int keyword_offset;
 
-  if (NULL == buf)
-  {
-    try_reconnect (sc);
-    return 0;
-  }
+  memset (&mbc, 0, sizeof (mbc));
   mbc.sc = sc;
-  mbc.skip_cnt = sc->search_request_map_offset;
-  sm = buf;
-  sm->header.type = htons (GNUNET_MESSAGE_TYPE_FS_START_SEARCH);
-  mbc.xoff = (struct GNUNET_HashCode *) &sm[1];
-  options = SEARCH_MESSAGE_OPTION_NONE;
-  if (0 != (sc->options & GNUNET_FS_SEARCH_OPTION_LOOPBACK_ONLY))
-    options |= SEARCH_MESSAGE_OPTION_LOOPBACK_ONLY;
   if (GNUNET_FS_uri_test_ksk (sc->uri))
   {
-    msize = sizeof (struct SearchMessage);
-    GNUNET_assert (size >= msize);
-    mbc.keyword_offset = sc->keyword_offset;
-    /* calculate total number of known results (in put_cnt => total_seen_results) */
     mbc.put_cnt = 0;
     GNUNET_CONTAINER_multihashmap_iterate (sc->master_result_map,
-                                           &find_result_set, &mbc);
+                                           &find_result_set,
+                                           &mbc);
     total_seen_results = mbc.put_cnt;
-    /* calculate how many results we can send in this message */
-    message_size_limit = (size - msize) / sizeof (struct GNUNET_HashCode);
-    mbc.put_cnt = GNUNET_MIN (message_size_limit,
-                              total_seen_results - mbc.skip_cnt);
-    if (sc->search_request_map_offset < total_seen_results)
-      GNUNET_assert (mbc.put_cnt > 0);
-
-    /* now build message */
-    msize += sizeof (struct GNUNET_HashCode) * mbc.put_cnt;
-    sm->header.size = htons (msize);
-    sm->type = htonl (GNUNET_BLOCK_TYPE_FS_UBLOCK);
-    sm->anonymity_level = htonl (sc->anonymity);
-    memset (&sm->target, 0, sizeof (struct GNUNET_PeerIdentity));
-    sm->query = sc->requests[sc->keyword_offset].uquery;
-    GNUNET_CONTAINER_multihashmap_iterate (sc->master_result_map,
-                                           &build_result_set, &mbc);
-    GNUNET_assert (0 == mbc.put_cnt);
-    GNUNET_assert (total_seen_results >= sc->search_request_map_offset);
-    if (total_seen_results != sc->search_request_map_offset)
-    {
-      /* more requesting to be done... */
-      sm->options = htonl (options | SEARCH_MESSAGE_OPTION_CONTINUED);
-      schedule_transmit_search_request (sc);
-      return msize;
-    }
-    sm->options = htonl (options);
-    sc->keyword_offset++;
-    sc->search_request_map_offset = 0;
-    if (sc->uri->data.ksk.keywordCount != sc->keyword_offset)
-    {
-      /* more requesting to be done... */
-      schedule_transmit_search_request (sc);
-      return msize;
-    }
   }
   else
   {
-    GNUNET_assert (GNUNET_FS_uri_test_sks (sc->uri));
-    msize = sizeof (struct SearchMessage);
-    GNUNET_assert (size >= msize);
-    sm->type = htonl (GNUNET_BLOCK_TYPE_FS_UBLOCK);
-    sm->anonymity_level = htonl (sc->anonymity);
-    memset (&sm->target, 0, sizeof (struct GNUNET_PeerIdentity));
-    GNUNET_CRYPTO_ecdsa_public_key_derive (&sc->uri->data.sks.ns,
-                                        sc->uri->data.sks.identifier,
-                                        "fs-ublock",
-                                        &dpub);
-    GNUNET_CRYPTO_hash (&dpub,
-                       sizeof (dpub),
-                       &sm->query);
-    message_size_limit = (size - msize) / sizeof (struct GNUNET_HashCode);
-    total_seen_results = GNUNET_CONTAINER_multihashmap_size (sc->master_result_map);
-    mbc.put_cnt = GNUNET_MIN (message_size_limit,
-                              total_seen_results - mbc.skip_cnt);
-    mbc.keyword_offset = 0;
-    if (sc->search_request_map_offset < total_seen_results)
-      GNUNET_assert (mbc.put_cnt > 0);
-    msize += sizeof (struct GNUNET_HashCode) * mbc.put_cnt;
-    GNUNET_CONTAINER_multihashmap_iterate (sc->master_result_map,
-                                           &build_result_set, &mbc);
-    sm->header.size = htons (msize);
-    GNUNET_assert (total_seen_results >= sc->search_request_map_offset);
-    if (total_seen_results != sc->search_request_map_offset)
+    total_seen_results
+      = GNUNET_CONTAINER_multihashmap_size (sc->master_result_map);
+  }
+  search_request_map_offset = 0;
+  keyword_offset = 0;
+
+  first_call = GNUNET_YES;
+  while ( (0 != (left =
+                 (total_seen_results - search_request_map_offset))) ||
+          (GNUNET_YES == first_call) )
+  {
+    first_call = GNUNET_NO;
+    options = SEARCH_MESSAGE_OPTION_NONE;
+    if (0 != (sc->options & GNUNET_FS_SEARCH_OPTION_LOOPBACK_ONLY))
+      options |= SEARCH_MESSAGE_OPTION_LOOPBACK_ONLY;
+
+    fit = (GNUNET_SERVER_MAX_MESSAGE_SIZE - 1 - sizeof (*sm)) / sizeof (struct GNUNET_HashCode);
+    todo = GNUNET_MIN (fit,
+                       left);
+    env = GNUNET_MQ_msg_extra (sm,
+                               sizeof (struct GNUNET_HashCode) * todo,
+                               GNUNET_MESSAGE_TYPE_FS_START_SEARCH);
+    mbc.skip_cnt = search_request_map_offset;
+    mbc.xoff = (struct GNUNET_HashCode *) &sm[1];
+
+    if (GNUNET_FS_uri_test_ksk (sc->uri))
     {
-      /* more requesting to be done... */
-      sm->options = htonl (options | SEARCH_MESSAGE_OPTION_CONTINUED);
-      schedule_transmit_search_request (sc);
-      return msize;
+      mbc.keyword_offset = keyword_offset;
+      /* calculate how many results we can send in this message */
+      mbc.put_cnt = todo;
+      /* now build message */
+      sm->type = htonl (GNUNET_BLOCK_TYPE_FS_UBLOCK);
+      sm->anonymity_level = htonl (sc->anonymity);
+      memset (&sm->target,
+              0,
+              sizeof (struct GNUNET_PeerIdentity));
+      sm->query = sc->requests[keyword_offset].uquery;
+      GNUNET_CONTAINER_multihashmap_iterate (sc->master_result_map,
+                                             &build_result_set,
+                                             &mbc);
+      search_request_map_offset += todo;
+      GNUNET_assert (0 == mbc.put_cnt); /* #4608 reports this fails? */
+      GNUNET_assert (total_seen_results >= search_request_map_offset);
+      if (total_seen_results != search_request_map_offset)
+      {
+        /* more requesting to be done... */
+        sm->options = htonl (options | SEARCH_MESSAGE_OPTION_CONTINUED);
+      }
+      else
+      {
+        sm->options = htonl (options);
+        keyword_offset++;
+        search_request_map_offset = 0;
+        if (sc->uri->data.ksk.keywordCount != keyword_offset)
+        {
+          /* more keywords => more requesting to be done... */
+          first_call = GNUNET_YES;
+        }
+      }
     }
-    sm->options = htonl (options);
+    else
+    {
+      GNUNET_assert (GNUNET_FS_uri_test_sks (sc->uri));
+
+      sm->type = htonl (GNUNET_BLOCK_TYPE_FS_UBLOCK);
+      sm->anonymity_level = htonl (sc->anonymity);
+      memset (&sm->target,
+              0,
+              sizeof (struct GNUNET_PeerIdentity));
+      GNUNET_CRYPTO_ecdsa_public_key_derive (&sc->uri->data.sks.ns,
+                                             sc->uri->data.sks.identifier,
+                                             "fs-ublock",
+                                             &dpub);
+      GNUNET_CRYPTO_hash (&dpub,
+                          sizeof (dpub),
+                          &sm->query);
+      mbc.put_cnt = todo;
+      mbc.keyword_offset = 0;
+      GNUNET_CONTAINER_multihashmap_iterate (sc->master_result_map,
+                                             &build_result_set,
+                                             &mbc);
+      GNUNET_assert (total_seen_results >= search_request_map_offset);
+      if (total_seen_results != search_request_map_offset)
+      {
+        /* more requesting to be done... */
+        sm->options = htonl (options | SEARCH_MESSAGE_OPTION_CONTINUED);
+      }
+      else
+      {
+        sm->options = htonl (options);
+      }
+    }
+    GNUNET_MQ_send (sc->mq,
+                    env);
   }
-  GNUNET_CLIENT_receive (sc->client,
-                         &receive_results, sc,
-                         GNUNET_TIME_UNIT_FOREVER_REL);
-  return msize;
 }
 
 
 /**
- * Schedule the transmission of the (next) search request
- * to the service.
+ * 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 sc context for the search
+ * @param cls closure with the `struct GNUNET_FS_SearchContext *`
+ * @param error error code
  */
 static void
-schedule_transmit_search_request (struct GNUNET_FS_SearchContext *sc)
+search_mq_error_handler (void *cls,
+                         enum GNUNET_MQ_Error error)
 {
-  size_t size;
-  unsigned int left;
-  unsigned int fit;
-  unsigned int request;
-
-  size = sizeof (struct SearchMessage);
-  left =
-      GNUNET_CONTAINER_multihashmap_size (sc->master_result_map) -
-      sc->search_request_map_offset;
-  fit = (GNUNET_SERVER_MAX_MESSAGE_SIZE - 1 - size) / sizeof (struct GNUNET_HashCode);
-  request = GNUNET_MIN (fit, left);
-  size += sizeof (struct GNUNET_HashCode) * request;
-  GNUNET_CLIENT_notify_transmit_ready (sc->client, size,
-                                       GNUNET_CONSTANTS_SERVICE_TIMEOUT,
-                                       GNUNET_NO,
-                                       &transmit_search_request, sc);
+  struct GNUNET_FS_SearchContext *sc = cls;
+
+  if (NULL != sc->mq)
+  {
+    GNUNET_MQ_destroy (sc->mq);
+    sc->mq = NULL;
+  }
+  try_reconnect (sc);
 }
 
 
@@ -1211,24 +1230,30 @@ schedule_transmit_search_request (struct GNUNET_FS_SearchContext *sc)
  * our queries NOW.
  *
  * @param cls our search context
- * @param tc unused
  */
 static void
-do_reconnect (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
+do_reconnect (void *cls)
 {
   struct GNUNET_FS_SearchContext *sc = cls;
-  struct GNUNET_CLIENT_Connection *client;
-
-  sc->task = GNUNET_SCHEDULER_NO_TASK;
-  client = GNUNET_CLIENT_connect ("fs", sc->h->cfg);
-  if (NULL == client)
+  struct GNUNET_MQ_MessageHandler handlers[] = {
+    GNUNET_MQ_hd_var_size (result,
+                           GNUNET_MESSAGE_TYPE_FS_PUT,
+                           struct ClientPutMessage,
+                           sc),
+    GNUNET_MQ_handler_end ()
+  };
+
+  sc->task = NULL;
+  sc->mq = GNUNET_CLIENT_connect (sc->h->cfg,
+                                  "fs",
+                                  handlers,
+                                  &search_mq_error_handler,
+                                  sc);
+  if (NULL == sc->mq)
   {
     try_reconnect (sc);
     return;
   }
-  sc->client = client;
-  sc->search_request_map_offset = 0;
-  sc->keyword_offset = 0;
   schedule_transmit_search_request (sc);
 }
 
@@ -1243,10 +1268,10 @@ do_reconnect (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
 static void
 try_reconnect (struct GNUNET_FS_SearchContext *sc)
 {
-  if (NULL != sc->client)
+  if (NULL != sc->mq)
   {
-    GNUNET_CLIENT_disconnect (sc->client);
-    sc->client = NULL;
+    GNUNET_MQ_destroy (sc->mq);
+    sc->mq = NULL;
   }
   sc->reconnect_backoff = GNUNET_TIME_STD_BACKOFF (sc->reconnect_backoff);
   sc->task =
@@ -1352,7 +1377,7 @@ GNUNET_FS_search_start_searching_ (struct GNUNET_FS_SearchContext *sc)
   struct GNUNET_CRYPTO_EcdsaPublicKey anon_pub;
   struct SearchRequestEntry *sre;
 
-  GNUNET_assert (NULL == sc->client);
+  GNUNET_assert (NULL == sc->mq);
   if (GNUNET_FS_uri_test_ksk (sc->uri))
   {
     GNUNET_assert (0 != sc->uri->data.ksk.keywordCount);
@@ -1382,11 +1407,14 @@ GNUNET_FS_search_start_searching_ (struct GNUNET_FS_SearchContext *sc)
                                            &update_sre_result_maps,
                                            sc);
   }
-  sc->client = GNUNET_CLIENT_connect ("fs", sc->h->cfg);
-  if (NULL == sc->client)
+  GNUNET_assert (NULL == sc->task);
+  do_reconnect (sc);
+  if (NULL == sc->mq)
+  {
+    GNUNET_SCHEDULER_cancel (sc->task);
+    sc->task = NULL;
     return GNUNET_SYSERR;
-  sc->search_request_map_offset = 0;
-  schedule_transmit_search_request (sc);
+  }
   return GNUNET_OK;
 }
 
@@ -1410,16 +1438,12 @@ search_result_freeze_probes (void *cls,
   {
     GNUNET_FS_download_stop (sr->probe_ctx, GNUNET_YES);
     sr->probe_ctx = NULL;
+    GNUNET_FS_stop_probe_ping_task_ (sr);
   }
-  if (GNUNET_SCHEDULER_NO_TASK != sr->probe_ping_task)
-  {
-    GNUNET_SCHEDULER_cancel (sr->probe_ping_task);
-    sr->probe_ping_task = GNUNET_SCHEDULER_NO_TASK;
-  }
-  if (GNUNET_SCHEDULER_NO_TASK != sr->probe_cancel_task)
+  if (NULL != sr->probe_cancel_task)
   {
     GNUNET_SCHEDULER_cancel (sr->probe_cancel_task);
-    sr->probe_cancel_task = GNUNET_SCHEDULER_NO_TASK;
+    sr->probe_cancel_task = NULL;
   }
   if (NULL != sr->update_search)
     GNUNET_FS_search_pause (sr->update_search);
@@ -1515,15 +1539,15 @@ GNUNET_FS_search_signal_suspend_ (void *cls)
   pi.status = GNUNET_FS_STATUS_SEARCH_SUSPEND;
   sc->client_info = GNUNET_FS_search_make_status_ (&pi, sc->h, sc);
   GNUNET_break (NULL == sc->client_info);
-  if (sc->task != GNUNET_SCHEDULER_NO_TASK)
+  if (sc->task != NULL)
   {
     GNUNET_SCHEDULER_cancel (sc->task);
-    sc->task = GNUNET_SCHEDULER_NO_TASK;
+    sc->task = NULL;
   }
-  if (NULL != sc->client)
+  if (NULL != sc->mq)
   {
-    GNUNET_CLIENT_disconnect (sc->client);
-    sc->client = NULL;
+    GNUNET_MQ_destroy (sc->mq);
+    sc->mq = NULL;
   }
   GNUNET_CONTAINER_multihashmap_destroy (sc->master_result_map);
   if (NULL != sc->requests)
@@ -1579,19 +1603,24 @@ GNUNET_FS_search_pause (struct GNUNET_FS_SearchContext *sc)
 {
   struct GNUNET_FS_ProgressInfo pi;
 
-  if (GNUNET_SCHEDULER_NO_TASK != sc->task)
+  if (NULL != sc->task)
   {
     GNUNET_SCHEDULER_cancel (sc->task);
-    sc->task = GNUNET_SCHEDULER_NO_TASK;
+    sc->task = NULL;
+  }
+  if (NULL != sc->mq)
+  {
+    GNUNET_MQ_destroy (sc->mq);
+    sc->mq = NULL;
   }
-  if (NULL != sc->client)
-    GNUNET_CLIENT_disconnect (sc->client);
-  sc->client = NULL;
   GNUNET_FS_search_sync_ (sc);
   GNUNET_CONTAINER_multihashmap_iterate (sc->master_result_map,
-                                         &search_result_freeze_probes, sc);
+                                         &search_result_freeze_probes,
+                                         sc);
   pi.status = GNUNET_FS_STATUS_SEARCH_PAUSED;
-  sc->client_info = GNUNET_FS_search_make_status_ (&pi, sc->h, sc);
+  sc->client_info = GNUNET_FS_search_make_status_ (&pi,
+                                                   sc->h,
+                                                   sc);
 }
 
 
@@ -1605,9 +1634,9 @@ GNUNET_FS_search_continue (struct GNUNET_FS_SearchContext *sc)
 {
   struct GNUNET_FS_ProgressInfo pi;
 
-  GNUNET_assert (NULL == sc->client);
-  GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == sc->task);
-  do_reconnect (sc, NULL);
+  GNUNET_assert (NULL == sc->mq);
+  GNUNET_assert (NULL == sc->task);
+  do_reconnect (sc);
   GNUNET_FS_search_sync_ (sc);
   pi.status = GNUNET_FS_STATUS_SEARCH_CONTINUED;
   sc->client_info = GNUNET_FS_search_make_status_ (&pi, sc->h, sc);
@@ -1691,8 +1720,7 @@ search_result_free (void *cls,
     GNUNET_assert (NULL == sr->update_search);
   }
   GNUNET_break (NULL == sr->probe_ctx);
-  GNUNET_break (GNUNET_SCHEDULER_NO_TASK == sr->probe_cancel_task);
-  GNUNET_break (GNUNET_SCHEDULER_NO_TASK == sr->probe_ping_task);
+  GNUNET_break (NULL == sr->probe_cancel_task);
   GNUNET_break (NULL == sr->client_info);
   GNUNET_free_non_null (sr->serialization);
   GNUNET_FS_uri_destroy (sr->uri);
@@ -1737,10 +1765,16 @@ GNUNET_FS_search_stop (struct GNUNET_FS_SearchContext *sc)
   pi.status = GNUNET_FS_STATUS_SEARCH_STOPPED;
   sc->client_info = GNUNET_FS_search_make_status_ (&pi, sc->h, sc);
   GNUNET_break (NULL == sc->client_info);
-  if (GNUNET_SCHEDULER_NO_TASK != sc->task)
+  if (NULL != sc->task)
+  {
     GNUNET_SCHEDULER_cancel (sc->task);
-  if (NULL != sc->client)
-    GNUNET_CLIENT_disconnect (sc->client);
+    sc->task = NULL;
+  }
+  if (NULL != sc->mq)
+  {
+    GNUNET_MQ_destroy (sc->mq);
+    sc->mq = NULL;
+  }
   GNUNET_CONTAINER_multihashmap_iterate (sc->master_result_map,
                                          &search_result_free, sc);
   GNUNET_CONTAINER_multihashmap_destroy (sc->master_result_map);