refactor DHT for new service API

7 files changed, 642 insertions, 789 deletions

diff --git a/src/dht/Makefile.am b/src/dht/Makefile.am
index f44721094..f7dc5df6d 100644
--- a/src/dht/Makefile.am
+++ b/src/dht/Makefile.am
@@ -63,7 +63,6 @@ noinst_PROGRAMS = \
 
 gnunet_service_dht_SOURCES = \
  gnunet-service-dht.c gnunet-service-dht.h \
- gnunet-service-dht_clients.c gnunet-service-dht_clients.h \
  gnunet-service-dht_datacache.c gnunet-service-dht_datacache.h \
  gnunet-service-dht_hello.c gnunet-service-dht_hello.h \
  gnunet-service-dht_nse.c gnunet-service-dht_nse.h \
diff --git a/src/dht/gnunet-service-dht.c b/src/dht/gnunet-service-dht.c
index 1e3dd339d..a2ba2e8b0 100644
--- a/src/dht/gnunet-service-dht.c
+++ b/src/dht/gnunet-service-dht.c
@@ -33,7 +33,6 @@
 #include "gnunet_dht_service.h"
 #include "gnunet_statistics_service.h"
 #include "gnunet-service-dht.h"
-#include "gnunet-service-dht_clients.h"
 #include "gnunet-service-dht_datacache.h"
 #include "gnunet-service-dht_hello.h"
 #include "gnunet-service-dht_neighbours.h"
@@ -47,6 +46,11 @@
 struct GNUNET_STATISTICS_Handle *GDS_stats;
 
 /**
+ * Handle for the service.
+ */
+struct GNUNET_SERVICE_Handle *GDS_service;
+
+/**
  * Our handle to the BLOCK library.
  */
 struct GNUNET_BLOCK_Context *GDS_block_context;
@@ -57,11 +61,6 @@ struct GNUNET_BLOCK_Context *GDS_block_context;
 const struct GNUNET_CONFIGURATION_Handle *GDS_cfg;
 
 /**
- * Handle to our server.
- */
-struct GNUNET_SERVER_Handle *GDS_server;
-
-/**
  * Our HELLO
  */
 struct GNUNET_MessageHeader *GDS_my_hello;
@@ -77,6 +76,10 @@ static struct GNUNET_TRANSPORT_HelloGetHandle *ghh;
 struct GNUNET_TIME_Relative hello_expiration;
 
 
+/* Code shared between different DHT implementations */
+#include "gnunet-service-dht_clients.c"
+
+
 /**
  * Receive the HELLO from transport service, free current and replace
  * if necessary.
@@ -90,7 +93,9 @@ process_hello (void *cls,
 {
   GNUNET_free_non_null (GDS_my_hello);
   GDS_my_hello = GNUNET_malloc (ntohs (message->size));
-  GNUNET_memcpy (GDS_my_hello, message, ntohs (message->size));
+  GNUNET_memcpy (GDS_my_hello,
+                 message,
+                 ntohs (message->size));
 }
 
 
@@ -133,17 +138,16 @@ shutdown_task (void *cls)
  * Process dht requests.
  *
  * @param cls closure
- * @param server the initialized server
  * @param c configuration to use
+ * @param service the initialized service
  */
 static void
 run (void *cls,
-     struct GNUNET_SERVER_Handle *server,
-     const struct GNUNET_CONFIGURATION_Handle *c)
+     const struct GNUNET_CONFIGURATION_Handle *c,
+     struct GNUNET_SERVICE_Handle *service)
 {
   GDS_cfg = c;
-  GDS_server = server;
-  GNUNET_SERVER_suspend (server);
+  GDS_service = service;
   if (GNUNET_OK !=
       GNUNET_CONFIGURATION_get_value_time (c,
                                            "transport",
@@ -153,7 +157,10 @@ run (void *cls,
     hello_expiration = GNUNET_CONSTANTS_HELLO_ADDRESS_EXPIRATION;
   }
   GDS_block_context = GNUNET_BLOCK_context_create (GDS_cfg);
-  GDS_stats = GNUNET_STATISTICS_create ("dht", GDS_cfg);
+  GDS_stats = GNUNET_STATISTICS_create ("dht",
+                                        GDS_cfg);
+  GNUNET_SERVICE_suspend (GDS_service);
+  GDS_CLIENTS_init ();
   GDS_ROUTING_init ();
   GDS_NSE_init ();
   GDS_DATACACHE_init ();
@@ -172,28 +179,10 @@ run (void *cls,
 }
 
 
-/**
- * The main function for the dht service.
- *
- * @param argc number of arguments from the command line
- * @param argv command line arguments
- * @return 0 ok, 1 on error
- */
-int
-main (int argc,
-      char *const *argv)
-{
-  int ret;
-
-  ret = (GNUNET_OK ==
-         GNUNET_SERVICE_run (argc,
-                             argv,
-                             "dht",
-                             GNUNET_SERVICE_OPTION_NONE,
-                             &run,
-                             NULL)) ? 0 : 1;
-  GDS_CLIENTS_done ();
-  return ret;
-}
+/* Finally, define the main method */
+GDS_DHT_SERVICE_INIT(&run);
+
+
+
 
 /* end of gnunet-service-dht.c */
diff --git a/src/dht/gnunet-service-dht.h b/src/dht/gnunet-service-dht.h
index 4684c2324..bc7a48b5a 100644
--- a/src/dht/gnunet-service-dht.h
+++ b/src/dht/gnunet-service-dht.h
@@ -1,6 +1,6 @@
 /*
      This file is part of GNUnet.
-     Copyright (C) 2011 GNUnet e.V.
+     Copyright (C) 2009-2016 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
@@ -29,6 +29,7 @@
 #include "gnunet_util_lib.h"
 #include "gnunet_statistics_service.h"
 #include "gnunet_transport_service.h"
+#include "gnunet_block_lib.h"
 
 #define DEBUG_DHT GNUNET_EXTRA_LOGGING
 
@@ -38,6 +39,11 @@
 extern const struct GNUNET_CONFIGURATION_Handle *GDS_cfg;
 
 /**
+ * Handle for the service.
+ */
+extern struct GNUNET_SERVICE_Handle *GDS_service;
+
+/**
  * Our handle to the BLOCK library.
  */
 extern struct GNUNET_BLOCK_Context *GDS_block_context;
@@ -48,14 +54,111 @@ extern struct GNUNET_BLOCK_Context *GDS_block_context;
 extern struct GNUNET_STATISTICS_Handle *GDS_stats;
 
 /**
- * Handle to our server.
+ * Our HELLO
  */
-extern struct GNUNET_SERVER_Handle *GDS_server;
+extern struct GNUNET_MessageHeader *GDS_my_hello;
+
+
 
 /**
- * Our HELLO
+ * Handle a reply we've received from another peer.  If the reply
+ * matches any of our pending queries, forward it to the respective
+ * client(s).
+ *
+ * @param expiration when will the reply expire
+ * @param key the query this reply is for
+ * @param get_path_length number of peers in @a get_path
+ * @param get_path path the reply took on get
+ * @param put_path_length number of peers in @a put_path
+ * @param put_path path the reply took on put
+ * @param type type of the reply
+ * @param data_size number of bytes in @a data
+ * @param data application payload data
  */
-extern struct GNUNET_MessageHeader *GDS_my_hello;
+void
+GDS_CLIENTS_handle_reply (struct GNUNET_TIME_Absolute expiration,
+                          const struct GNUNET_HashCode *key,
+                          unsigned int get_path_length,
+                          const struct GNUNET_PeerIdentity *get_path,
+                          unsigned int put_path_length,
+                          const struct GNUNET_PeerIdentity *put_path,
+                          enum GNUNET_BLOCK_Type type, size_t data_size,
+                          const void *data);
+
 
+/**
+ * Check if some client is monitoring GET messages and notify
+ * them in that case.
+ *
+ * @param options Options, for instance RecordRoute, DemultiplexEverywhere.
+ * @param type The type of data in the request.
+ * @param hop_count Hop count so far.
+ * @param path_length number of entries in path (or 0 if not recorded).
+ * @param path peers on the GET path (or NULL if not recorded).
+ * @param desired_replication_level Desired replication level.
+ * @param key Key of the requested data.
+ */
+void
+GDS_CLIENTS_process_get (uint32_t options,
+                         enum GNUNET_BLOCK_Type type,
+                         uint32_t hop_count,
+                         uint32_t desired_replication_level,
+                         unsigned int path_length,
+                         const struct GNUNET_PeerIdentity *path,
+                         const struct GNUNET_HashCode *key);
+
+
+/**
+ * Check if some client is monitoring GET RESP messages and notify
+ * them in that case.
+ *
+ * @param type The type of data in the result.
+ * @param get_path Peers on GET path (or NULL if not recorded).
+ * @param get_path_length number of entries in @a get_path.
+ * @param put_path peers on the PUT path (or NULL if not recorded).
+ * @param put_path_length number of entries in @a get_path.
+ * @param exp Expiration time of the data.
+ * @param key Key of the @a data.
+ * @param data Pointer to the result data.
+ * @param size Number of bytes in @a data.
+ */
+void
+GDS_CLIENTS_process_get_resp (enum GNUNET_BLOCK_Type type,
+                              const struct GNUNET_PeerIdentity *get_path,
+                              unsigned int get_path_length,
+                              const struct GNUNET_PeerIdentity *put_path,
+                              unsigned int put_path_length,
+                              struct GNUNET_TIME_Absolute exp,
+                              const struct GNUNET_HashCode * key,
+                              const void *data,
+                              size_t size);
+
+
+/**
+ * Check if some client is monitoring PUT messages and notify
+ * them in that case.
+ *
+ * @param options Options, for instance RecordRoute, DemultiplexEverywhere.
+ * @param type The type of data in the request.
+ * @param hop_count Hop count so far.
+ * @param path_length number of entries in path (or 0 if not recorded).
+ * @param path peers on the PUT path (or NULL if not recorded).
+ * @param desired_replication_level Desired replication level.
+ * @param exp Expiration time of the data.
+ * @param key Key under which data is to be stored.
+ * @param data Pointer to the data carried.
+ * @param size Number of bytes in data.
+ */
+void
+GDS_CLIENTS_process_put (uint32_t options,
+                         enum GNUNET_BLOCK_Type type,
+                         uint32_t hop_count,
+                         uint32_t desired_replication_level,
+                         unsigned int path_length,
+                         const struct GNUNET_PeerIdentity *path,
+                         struct GNUNET_TIME_Absolute exp,
+                         const struct GNUNET_HashCode * key,
+                         const void *data,
+                         size_t size);
 
 #endif
diff --git a/src/dht/gnunet-service-dht_clients.c b/src/dht/gnunet-service-dht_clients.c
index 9dbeef6bd..0e344b566 100644
--- a/src/dht/gnunet-service-dht_clients.c
+++ b/src/dht/gnunet-service-dht_clients.c
@@ -1,6 +1,6 @@
 /*
      This file is part of GNUnet.
-     Copyright (C) 2009, 2010, 2011 GNUnet e.V.
+     Copyright (C) 2009, 2010, 2011, 2016 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
@@ -30,7 +30,6 @@
 #include "gnunet_protocols.h"
 #include "gnunet_statistics_service.h"
 #include "gnunet-service-dht.h"
-#include "gnunet-service-dht_clients.h"
 #include "gnunet-service-dht_datacache.h"
 #include "gnunet-service-dht_neighbours.h"
 #include "dht.h"
@@ -43,70 +42,13 @@
 
 #define LOG(kind,...) GNUNET_log_from (kind, "dht-clients",__VA_ARGS__)
 
-/**
- * Linked list of messages to send to clients.
- */
-struct PendingMessage
-{
-  /**
-   * Pointer to next item in the list
-   */
-  struct PendingMessage *next;
-
-  /**
-   * Pointer to previous item in the list
-   */
-  struct PendingMessage *prev;
-
-  /**
-   * Actual message to be sent, allocated at the end of the struct:
-   * // msg = (cast) &pm[1];
-   * // GNUNET_memcpy (&pm[1], data, len);
-   */
-  const struct GNUNET_MessageHeader *msg;
-
-};
-
 
 /**
  * Struct containing information about a client,
  * handle to connect to it, and any pending messages
  * that need to be sent to it.
  */
-struct ClientList
-{
-  /**
-   * Linked list of active clients
-   */
-  struct ClientList *next;
-
-  /**
-   * Linked list of active clients
-   */
-  struct ClientList *prev;
-
-  /**
-   * The handle to this client
-   */
-  struct GNUNET_SERVER_Client *client_handle;
-
-  /**
-   * Handle to the current transmission request, NULL
-   * if none pending.
-   */
-  struct GNUNET_SERVER_TransmitHandle *transmit_handle;
-
-  /**
-   * Linked list of pending messages for this client
-   */
-  struct PendingMessage *pending_head;
-
-  /**
-   * Tail of linked list of pending messages for this client
-   */
-  struct PendingMessage *pending_tail;
-
-};
+struct ClientHandle;
 
 
 /**
@@ -121,9 +63,19 @@ struct ClientQueryRecord
   struct GNUNET_HashCode key;
 
   /**
+   * Kept in a DLL with @e client.
+   */
+  struct ClientQueryRecord *next;
+
+  /**
+   * Kept in a DLL with @e client.
+   */
+  struct ClientQueryRecord *prev;
+
+  /**
    * Client responsible for the request.
    */
-  struct ClientList *client;
+  struct ClientHandle *ch;
 
   /**
    * Extended query (see gnunet_block_lib.h), allocated at the end of this struct.
@@ -193,22 +145,22 @@ struct ClientMonitorRecord
   /**
    * Next element in DLL.
    */
-  struct ClientMonitorRecord    *next;
+  struct ClientMonitorRecord *next;
 
   /**
    * Previous element in DLL.
    */
-  struct ClientMonitorRecord    *prev;
+  struct ClientMonitorRecord *prev;
 
   /**
    * Type of blocks that are of interest
    */
-  enum GNUNET_BLOCK_Type        type;
+  enum GNUNET_BLOCK_Type type;
 
   /**
    * Key of data of interest, NULL for all.
    */
-  struct GNUNET_HashCode         *key;
+  struct GNUNET_HashCode *key;
 
   /**
    * Flag whether to notify about GET messages.
@@ -228,19 +180,39 @@ struct ClientMonitorRecord
   /**
    * Client to notify of these requests.
    */
-  struct ClientList             *client;
+  struct ClientHandle *ch;
 };
 
 
 /**
- * List of active clients.
+ * Struct containing information about a client,
+ * handle to connect to it, and any pending messages
+ * that need to be sent to it.
  */
-static struct ClientList *client_head;
+struct ClientHandle
+{
+  /**
+   * Linked list of active queries of this client.
+   */
+  struct ClientQueryRecord *cqr_head;
+
+  /**
+   * Linked list of active queries of this client.
+   */
+  struct ClientQueryRecord *cqr_tail;
+
+  /**
+   * The handle to this client
+   */
+  struct GNUNET_SERVICE_Client *client;
+
+  /**
+   * The message queue to this client
+   */
+  struct GNUNET_MQ_Handle *mq;
+
+};
 
-/**
- * List of active clients.
- */
-static struct ClientList *client_tail;
 
 /**
  * List of active monitoring requests.
@@ -265,88 +237,55 @@ static struct GNUNET_CONTAINER_Heap *retry_heap;
 /**
  * Task that re-transmits requests (using retry_heap).
  */
-static struct GNUNET_SCHEDULER_Task * retry_task;
+static struct GNUNET_SCHEDULER_Task *retry_task;
 
 
 /**
- * Task run to check for messages that need to be sent to a client.
+ * Free data structures associated with the given query.
  *
- * @param client a ClientList, containing the client and any messages to be sent to it
+ * @param record record to remove
  */
 static void
-process_pending_messages (struct ClientList *client);
-
-
-/**
- * Add a PendingMessage to the clients list of messages to be sent
- *
- * @param client the active client to send the message to
- * @param pending_message the actual message to send
- */
-static void
-add_pending_message (struct ClientList *client,
-                     struct PendingMessage *pending_message)
+remove_client_record (struct ClientQueryRecord *record)
 {
-  GNUNET_CONTAINER_DLL_insert_tail (client->pending_head, client->pending_tail,
-                                    pending_message);
-  process_pending_messages (client);
-}
+  struct ClientHandle *ch = record->ch;
 
-
-/**
- * Find a client if it exists, add it otherwise.
- *
- * @param client the server handle to the client
- *
- * @return the client if found, a new client otherwise
- */
-static struct ClientList *
-find_active_client (struct GNUNET_SERVER_Client *client)
-{
-  struct ClientList *pos = client_head;
-  struct ClientList *ret;
-
-  while (pos != NULL)
-  {
-    if (pos->client_handle == client)
-      return pos;
-    pos = pos->next;
-  }
-  ret = GNUNET_new (struct ClientList);
-  ret->client_handle = client;
-  GNUNET_CONTAINER_DLL_insert (client_head, client_tail, ret);
-  return ret;
+  GNUNET_CONTAINER_DLL_remove (ch->cqr_head,
+                               ch->cqr_tail,
+                               record);
+  GNUNET_assert (GNUNET_YES ==
+                 GNUNET_CONTAINER_multihashmap_remove (forward_map,
+                                                       &record->key,
+                                                       record));
+  if (NULL != record->hnode)
+    GNUNET_CONTAINER_heap_remove_node (record->hnode);
+  GNUNET_array_grow (record->seen_replies,
+                     record->seen_replies_count,
+                     0);
+  GNUNET_free (record);
 }
 
 
 /**
- * Iterator over hash map entries that frees all entries
- * associated with the given client.
+ * Functions with this signature are called whenever a local client is
+ * connects to us.
  *
- * @param cls client to search for in source routes
- * @param key current key code (ignored)
- * @param value value in the hash map, a ClientQueryRecord
- * @return #GNUNET_YES (we should continue to iterate)
+ * @param cls closure (NULL for dht)
+ * @param client identification of the client
+ * @param mq message queue for talking to @a client
+ * @return our `struct ClientHandle` for @a client
  */
-static int
-remove_client_records (void *cls, const struct GNUNET_HashCode * key, void *value)
+static void *
+client_connect_cb (void *cls,
+                   struct GNUNET_SERVICE_Client *client,
+                   struct GNUNET_MQ_Handle *mq)
 {
-  struct ClientList *client = cls;
-  struct ClientQueryRecord *record = value;
+  struct ClientHandle *ch;
 
-  if (record->client != client)
-    return GNUNET_YES;
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              "Removing client %p's record for key %s\n", client,
-              GNUNET_h2s (key));
-  GNUNET_assert (GNUNET_YES ==
-                 GNUNET_CONTAINER_multihashmap_remove (forward_map, key,
-                                                       record));
-  if (NULL != record->hnode)
-    GNUNET_CONTAINER_heap_remove_node (record->hnode);
-  GNUNET_array_grow (record->seen_replies, record->seen_replies_count, 0);
-  GNUNET_free (record);
-  return GNUNET_YES;
+  ch = GNUNET_new (struct ClientHandle);
+  ch->client = client;
+  ch->mq = mq;
+  return ch;
 }
 
 
@@ -355,48 +294,44 @@ remove_client_records (void *cls, const struct GNUNET_HashCode * key, void *valu
  * is disconnected on the network level.
  *
  * @param cls closure (NULL for dht)
- * @param client identification of the client; NULL
- *        for the last call when the server is destroyed
+ * @param client identification of the client
+ * @param app_ctx our `struct ClientHandle` for @a client
  */
 static void
-handle_client_disconnect (void *cls,
-                          struct GNUNET_SERVER_Client *client)
+client_disconnect_cb (void *cls,
+                      struct GNUNET_SERVICE_Client *client,
+                      void *app_ctx)
 {
-  struct ClientList *pos;
-  struct PendingMessage *reply;
+  struct ClientHandle *ch = app_ctx;
+  struct ClientQueryRecord *cqr;
   struct ClientMonitorRecord *monitor;
 
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
               "Local client %p disconnects\n",
-              client);
-  pos = find_active_client (client);
-  GNUNET_CONTAINER_DLL_remove (client_head, client_tail, pos);
-  if (pos->transmit_handle != NULL)
-    GNUNET_SERVER_notify_transmit_ready_cancel (pos->transmit_handle);
-  while (NULL != (reply = pos->pending_head))
-  {
-    GNUNET_CONTAINER_DLL_remove (pos->pending_head, pos->pending_tail, reply);
-    GNUNET_free (reply);
-  }
+              ch);
   monitor = monitor_head;
   while (NULL != monitor)
   {
-    if (monitor->client == pos)
+    if (monitor->ch == ch)
     {
       struct ClientMonitorRecord *next;
 
-      GNUNET_free_non_null (monitor->key);
       next = monitor->next;
-      GNUNET_CONTAINER_DLL_remove (monitor_head, monitor_tail, monitor);
+      GNUNET_free_non_null (monitor->key);
+      GNUNET_CONTAINER_DLL_remove (monitor_head,
+                                   monitor_tail,
+                                   monitor);
       GNUNET_free (monitor);
       monitor = next;
     }
     else
+    {
       monitor = monitor->next;
+    }
   }
-  GNUNET_CONTAINER_multihashmap_iterate (forward_map, &remove_client_records,
-                                         pos);
-  GNUNET_free (pos);
+  while (NULL != (cqr = ch->cqr_head))
+    remove_client_record (cqr);
+  GNUNET_free (ch);
 }
 
 
@@ -413,27 +348,35 @@ transmit_request (struct ClientQueryRecord *cqr)
   struct GNUNET_CONTAINER_BloomFilter *peer_bf;
 
   GNUNET_STATISTICS_update (GDS_stats,
-                            gettext_noop
-                            ("# GET requests from clients injected"), 1,
+                            gettext_noop ("# GET requests from clients injected"),
+                            1,
                             GNUNET_NO);
   reply_bf_mutator =
       (int32_t) GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK,
                                           UINT32_MAX);
-  reply_bf =
-      GNUNET_BLOCK_construct_bloomfilter (reply_bf_mutator, cqr->seen_replies,
+  reply_bf
+    = GNUNET_BLOCK_construct_bloomfilter (reply_bf_mutator,
+                                          cqr->seen_replies,
                                           cqr->seen_replies_count);
-  peer_bf =
-      GNUNET_CONTAINER_bloomfilter_init (NULL, DHT_BLOOM_SIZE,
+  peer_bf
+    = GNUNET_CONTAINER_bloomfilter_init (NULL,
+                                         DHT_BLOOM_SIZE,
                                          GNUNET_CONSTANTS_BLOOMFILTER_K);
   LOG (GNUNET_ERROR_TYPE_DEBUG,
        "Initiating GET for %s, replication %u, already have %u replies\n",
        GNUNET_h2s (&cqr->key),
        cqr->replication,
        cqr->seen_replies_count);
-  GDS_NEIGHBOURS_handle_get (cqr->type, cqr->msg_options, cqr->replication,
+  GDS_NEIGHBOURS_handle_get (cqr->type,
+                             cqr->msg_options,
+                             cqr->replication,
                              0 /* hop count */ ,
-                             &cqr->key, cqr->xquery, cqr->xquery_size, reply_bf,
-                             reply_bf_mutator, peer_bf);
+                             &cqr->key,
+                             cqr->xquery,
+                             cqr->xquery_size,
+                             reply_bf,
+                             reply_bf_mutator,
+                             peer_bf);
   GNUNET_CONTAINER_bloomfilter_free (reply_bf);
   GNUNET_CONTAINER_bloomfilter_free (peer_bf);
 
@@ -445,7 +388,7 @@ transmit_request (struct ClientQueryRecord *cqr)
 
 
 /**
- * Task that looks at the 'retry_heap' and transmits all of the requests
+ * Task that looks at the #retry_heap and transmits all of the requests
  * on the heap that are ready for transmission.  Then re-schedules
  * itself (unless the heap is empty).
  *
@@ -465,51 +408,62 @@ transmit_next_request_task (void *cls)
     if (delay.rel_value_us > 0)
     {
       cqr->hnode =
-          GNUNET_CONTAINER_heap_insert (retry_heap, cqr,
+          GNUNET_CONTAINER_heap_insert (retry_heap,
+                                        cqr,
                                         cqr->retry_time.abs_value_us);
       retry_task =
-          GNUNET_SCHEDULER_add_delayed (delay, &transmit_next_request_task,
+          GNUNET_SCHEDULER_add_delayed (delay,
+                                        &transmit_next_request_task,
                                         NULL);
       return;
     }
     transmit_request (cqr);
-    cqr->hnode =
-        GNUNET_CONTAINER_heap_insert (retry_heap, cqr,
+    cqr->hnode
+      = GNUNET_CONTAINER_heap_insert (retry_heap, cqr,
                                       cqr->retry_time.abs_value_us);
   }
 }
 
 
 /**
+ * Check DHT PUT messages from the client.
+ *
+ * @param cls the client we received this message from
+ * @param dht_msg the actual message received
+ * @return #GNUNET_OK (always)
+ */
+static int
+check_dht_local_put (void *cls,
+                      const struct GNUNET_DHT_ClientPutMessage *dht_msg)
+{
+  /* always well-formed */
+  return GNUNET_OK;
+}
+
+
+/**
  * Handler for PUT messages.
  *
- * @param cls closure for the service
- * @param client the client we received this message from
- * @param message the actual message received
+ * @param cls the client we received this message from
+ * @param dht_msg the actual message received
  */
 static void
-handle_dht_local_put (void *cls, struct GNUNET_SERVER_Client *client,
-                      const struct GNUNET_MessageHeader *message)
+handle_dht_local_put (void *cls,
+                      const struct GNUNET_DHT_ClientPutMessage *dht_msg)
 {
-  const struct GNUNET_DHT_ClientPutMessage *dht_msg;
+  struct ClientHandle *ch = cls;
   struct GNUNET_CONTAINER_BloomFilter *peer_bf;
   uint16_t size;
-  struct PendingMessage *pm;
+  struct GNUNET_MQ_Envelope *env;
   struct GNUNET_DHT_ClientPutConfirmationMessage *conf;
 
-  size = ntohs (message->size);
-  if (size < sizeof (struct GNUNET_DHT_ClientPutMessage))
-  {
-    GNUNET_break (0);
-    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
-    return;
-  }
+  size = ntohs (dht_msg->header.size);
   GNUNET_STATISTICS_update (GDS_stats,
-                            gettext_noop
-                            ("# PUT requests received from clients"), 1,
+                            gettext_noop ("# PUT requests received from clients"),
+                            1,
                             GNUNET_NO);
-  dht_msg = (const struct GNUNET_DHT_ClientPutMessage *) message;
-  LOG_TRAFFIC (GNUNET_ERROR_TYPE_DEBUG, "R5N CLIENT-PUT %s\n",
+  LOG_TRAFFIC (GNUNET_ERROR_TYPE_DEBUG,
+               "CLIENT-PUT %s\n",
                GNUNET_h2s_full (&dht_msg->key));
   /* give to local clients */
   LOG (GNUNET_ERROR_TYPE_DEBUG,
@@ -517,26 +471,38 @@ handle_dht_local_put (void *cls, struct GNUNET_SERVER_Client *client,
        size - sizeof (struct GNUNET_DHT_ClientPutMessage),
        GNUNET_h2s (&dht_msg->key));
   GDS_CLIENTS_handle_reply (GNUNET_TIME_absolute_ntoh (dht_msg->expiration),
-                            &dht_msg->key, 0, NULL, 0, NULL,
+                            &dht_msg->key,
+                            0,
+                            NULL,
+                            0,
+                            NULL,
                             ntohl (dht_msg->type),
                             size - sizeof (struct GNUNET_DHT_ClientPutMessage),
                             &dht_msg[1]);
   /* store locally */
   GDS_DATACACHE_handle_put (GNUNET_TIME_absolute_ntoh (dht_msg->expiration),
-                            &dht_msg->key, 0, NULL, ntohl (dht_msg->type),
+                            &dht_msg->key,
+                            0,
+                            NULL,
+                            ntohl (dht_msg->type),
                             size - sizeof (struct GNUNET_DHT_ClientPutMessage),
                             &dht_msg[1]);
   /* route to other peers */
-  peer_bf =
-      GNUNET_CONTAINER_bloomfilter_init (NULL, DHT_BLOOM_SIZE,
+  peer_bf
+    = GNUNET_CONTAINER_bloomfilter_init (NULL,
+                                         DHT_BLOOM_SIZE,
                                          GNUNET_CONSTANTS_BLOOMFILTER_K);
-  GDS_NEIGHBOURS_handle_put (ntohl (dht_msg->type), ntohl (dht_msg->options),
+  GDS_NEIGHBOURS_handle_put (ntohl (dht_msg->type),
+                             ntohl (dht_msg->options),
                              ntohl (dht_msg->desired_replication_level),
                              GNUNET_TIME_absolute_ntoh (dht_msg->expiration),
                              0 /* hop count */ ,
-                             peer_bf, &dht_msg->key, 0, NULL, &dht_msg[1],
-                             size -
-                             sizeof (struct GNUNET_DHT_ClientPutMessage));
+                             peer_bf,
+                             &dht_msg->key,
+                             0,
+                             NULL,
+                             &dht_msg[1],
+                             size - sizeof (struct GNUNET_DHT_ClientPutMessage));
   GDS_CLIENTS_process_put (ntohl (dht_msg->options),
                            ntohl (dht_msg->type),
                            0,
@@ -548,45 +514,50 @@ handle_dht_local_put (void *cls, struct GNUNET_SERVER_Client *client,
                            &dht_msg[1],
                            size - sizeof (struct GNUNET_DHT_ClientPutMessage));
   GNUNET_CONTAINER_bloomfilter_free (peer_bf);
-  pm = GNUNET_malloc (sizeof (struct PendingMessage) +
-                      sizeof (struct GNUNET_DHT_ClientPutConfirmationMessage));
-  conf = (struct GNUNET_DHT_ClientPutConfirmationMessage *) &pm[1];
-  conf->header.size = htons (sizeof (struct GNUNET_DHT_ClientPutConfirmationMessage));
-  conf->header.type = htons (GNUNET_MESSAGE_TYPE_DHT_CLIENT_PUT_OK);
+  env = GNUNET_MQ_msg (conf,
+                       GNUNET_MESSAGE_TYPE_DHT_CLIENT_PUT_OK);
   conf->reserved = htonl (0);
   conf->unique_id = dht_msg->unique_id;
-  pm->msg = &conf->header;
-  add_pending_message (find_active_client (client), pm);
-  GNUNET_SERVER_receive_done (client, GNUNET_OK);
+  GNUNET_MQ_send (ch->mq,
+                  env);
+  GNUNET_SERVICE_client_continue (ch->client);
+}
+
+
+/**
+ * Check DHT GET messages from the client.
+ *
+ * @param cls the client we received this message from
+ * @param message the actual message received
+ * @return #GNUNET_OK (always)
+ */
+static int
+check_dht_local_get (void *cls,
+                      const struct GNUNET_DHT_ClientGetMessage *get)
+{
+  /* always well-formed */
+  return GNUNET_OK;
 }
 
 
 /**
  * Handler for DHT GET messages from the client.
  *
- * @param cls closure for the service
- * @param client the client we received this message from
+ * @param cls the client we received this message from
  * @param message the actual message received
  */
 static void
-handle_dht_local_get (void *cls, struct GNUNET_SERVER_Client *client,
-                      const struct GNUNET_MessageHeader *message)
+handle_dht_local_get (void *cls,
+                      const struct GNUNET_DHT_ClientGetMessage *get)
 {
-  const struct GNUNET_DHT_ClientGetMessage *get;
+  struct ClientHandle *ch = cls;
   struct ClientQueryRecord *cqr;
   size_t xquery_size;
   const char *xquery;
   uint16_t size;
 
-  size = ntohs (message->size);
-  if (size < sizeof (struct GNUNET_DHT_ClientGetMessage))
-  {
-    GNUNET_break (0);
-    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
-    return;
-  }
+  size = ntohs (get->header.size);
   xquery_size = size - sizeof (struct GNUNET_DHT_ClientGetMessage);
-  get = (const struct GNUNET_DHT_ClientGetMessage *) message;
   xquery = (const char *) &get[1];
   GNUNET_STATISTICS_update (GDS_stats,
                             gettext_noop
@@ -594,15 +565,17 @@ handle_dht_local_get (void *cls, struct GNUNET_SERVER_Client *client,
                             GNUNET_NO);
   LOG (GNUNET_ERROR_TYPE_DEBUG,
        "Received GET request for %s from local client %p, xq: %.*s\n",
-       GNUNET_h2s (&get->key), client, xquery_size, xquery);
-
-  LOG_TRAFFIC (GNUNET_ERROR_TYPE_DEBUG, "R5N CLIENT-GET %s\n",
+       GNUNET_h2s (&get->key),
+       ch->client,
+       xquery_size,
+       xquery);
+  LOG_TRAFFIC (GNUNET_ERROR_TYPE_DEBUG,
+               "CLIENT-GET %s\n",
                GNUNET_h2s_full (&get->key));
 
-
   cqr = GNUNET_malloc (sizeof (struct ClientQueryRecord) + xquery_size);
   cqr->key = get->key;
-  cqr->client = find_active_client (client);
+  cqr->ch = ch;
   cqr->xquery = (void *) &cqr[1];
   GNUNET_memcpy (&cqr[1], xquery, xquery_size);
   cqr->hnode = GNUNET_CONTAINER_heap_insert (retry_heap, cqr, 0);
@@ -613,8 +586,12 @@ handle_dht_local_get (void *cls, struct GNUNET_SERVER_Client *client,
   cqr->replication = ntohl (get->desired_replication_level);
   cqr->msg_options = ntohl (get->options);
   cqr->type = ntohl (get->type);
-  // FIXME use cqr->key, set multihashmap create to GNUNET_YES
-  GNUNET_CONTAINER_multihashmap_put (forward_map, &get->key, cqr,
+  GNUNET_CONTAINER_DLL_insert (ch->cqr_head,
+                               ch->cqr_tail,
+                               cqr);
+  GNUNET_CONTAINER_multihashmap_put (forward_map,
+                                     &cqr->key,
+                                     cqr,
                                      GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE);
   GDS_CLIENTS_process_get (ntohl (get->options),
                            ntohl (get->type),
@@ -635,13 +612,12 @@ handle_dht_local_get (void *cls, struct GNUNET_SERVER_Client *client,
                             xquery_size,
                             NULL,
                             0);
-  GNUNET_SERVER_receive_done (client,
-                              GNUNET_OK);
+  GNUNET_SERVICE_client_continue (ch->client);
 }
 
 
 /**
- * Closure for 'find_by_unique_id'.
+ * Closure for #find_by_unique_id().
  */
 struct FindByUniqueIdContext
 {
@@ -661,8 +637,8 @@ struct FindByUniqueIdContext
  *
  * @param cls the search context
  * @param key query for the lookup (not used)
- * @param value the 'struct ClientQueryRecord'
- * @return GNUNET_YES to continue iteration (result not yet found)
+ * @param value the `struct ClientQueryRecord`
+ * @return #GNUNET_YES to continue iteration (result not yet found)
  */
 static int
 find_by_unique_id (void *cls,
@@ -680,17 +656,41 @@ find_by_unique_id (void *cls,
 
 
 /**
+ * Check "GET result seen" messages from the client.
+ *
+ * @param cls the client we received this message from
+ * @param message the actual message received
+ * @return #GNUNET_OK if @a seen is well-formed
+ */
+static int
+check_dht_local_get_result_seen (void *cls,
+                                 const struct GNUNET_DHT_ClientGetResultSeenMessage *seen)
+{
+  uint16_t size;
+  unsigned int hash_count;
+
+  size = ntohs (seen->header.size);
+  hash_count = (size - sizeof (struct GNUNET_DHT_ClientGetResultSeenMessage)) / sizeof (struct GNUNET_HashCode);
+  if (size != sizeof (struct GNUNET_DHT_ClientGetResultSeenMessage) + hash_count * sizeof (struct GNUNET_HashCode))
+  {
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+  return GNUNET_OK;
+}
+
+
+/**
  * Handler for "GET result seen" messages from the client.
  *
- * @param cls closure for the service
- * @param client the client we received this message from
+ * @param cls the client we received this message from
  * @param message the actual message received
  */
 static void
-handle_dht_local_get_result_seen (void *cls, struct GNUNET_SERVER_Client *client,
-                                  const struct GNUNET_MessageHeader *message)
+handle_dht_local_get_result_seen (void *cls,
+                                  const struct GNUNET_DHT_ClientGetResultSeenMessage *seen)
 {
-  const struct GNUNET_DHT_ClientGetResultSeenMessage *seen;
+  struct ClientHandle *ch = cls;
   uint16_t size;
   unsigned int hash_count;
   unsigned int old_count;
@@ -698,21 +698,8 @@ handle_dht_local_get_result_seen (void *cls, struct GNUNET_SERVER_Client *client
   struct FindByUniqueIdContext fui_ctx;
   struct ClientQueryRecord *cqr;
 
-  size = ntohs (message->size);
-  if (size < sizeof (struct GNUNET_DHT_ClientGetResultSeenMessage))
-  {
-    GNUNET_break (0);
-    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
-    return;
-  }
-  seen = (const struct GNUNET_DHT_ClientGetResultSeenMessage *) message;
+  size = ntohs (seen->header.size);
   hash_count = (size - sizeof (struct GNUNET_DHT_ClientGetResultSeenMessage)) / sizeof (struct GNUNET_HashCode);
-  if (size != sizeof (struct GNUNET_DHT_ClientGetResultSeenMessage) + hash_count * sizeof (struct GNUNET_HashCode))
-  {
-    GNUNET_break (0);
-    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
-    return;
-  }
   hc = (const struct GNUNET_HashCode*) &seen[1];
   fui_ctx.unique_id = seen->unique_id;
   fui_ctx.cqr = NULL;
@@ -723,7 +710,7 @@ handle_dht_local_get_result_seen (void *cls, struct GNUNET_SERVER_Client *client
   if (NULL == (cqr = fui_ctx.cqr))
   {
     GNUNET_break (0);
-    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
+    GNUNET_SERVICE_client_drop (ch->client);
     return;
   }
   /* finally, update 'seen' list */
@@ -732,20 +719,20 @@ handle_dht_local_get_result_seen (void *cls, struct GNUNET_SERVER_Client *client
                      cqr->seen_replies_count,
                      cqr->seen_replies_count + hash_count);
   GNUNET_memcpy (&cqr->seen_replies[old_count],
-          hc,
-          sizeof (struct GNUNET_HashCode) * hash_count);
+                 hc,
+                 sizeof (struct GNUNET_HashCode) * hash_count);
 }
 
 
 /**
- * Closure for 'remove_by_unique_id'.
+ * Closure for #remove_by_unique_id().
  */
 struct RemoveByUniqueIdContext
 {
   /**
    * Client that issued the removal request.
    */
-  struct ClientList *client;
+  struct ClientHandle *ch;
 
   /**
    * Unique ID of the request.
@@ -761,20 +748,24 @@ struct RemoveByUniqueIdContext
  * @param cls unique ID and client to search for in source routes
  * @param key current key code
  * @param value value in the hash map, a ClientQueryRecord
- * @return GNUNET_YES (we should continue to iterate)
+ * @return #GNUNET_YES (we should continue to iterate)
  */
 static int
-remove_by_unique_id (void *cls, const struct GNUNET_HashCode * key, void *value)
+remove_by_unique_id (void *cls,
+                     const struct GNUNET_HashCode *key,
+                     void *value)
 {
   const struct RemoveByUniqueIdContext *ctx = cls;
-  struct ClientQueryRecord *record = value;
+  struct ClientQueryRecord *cqr = value;
 
-  if (record->unique_id != ctx->unique_id)
+  if (cqr->unique_id != ctx->unique_id)
     return GNUNET_YES;
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
               "Removing client %p's record for key %s (by unique id)\n",
-              ctx->client->client_handle, GNUNET_h2s (key));
-  return remove_client_records (ctx->client, key, record);
+              ctx->ch->client,
+              GNUNET_h2s (key));
+  remove_client_record (cqr);
+  return GNUNET_YES;
 }
 
 
@@ -782,18 +773,15 @@ remove_by_unique_id (void *cls, const struct GNUNET_HashCode * key, void *value)
  * Handler for any generic DHT stop messages, calls the appropriate handler
  * depending on message type (if processed locally)
  *
- * @param cls closure for the service
- * @param client the client we received this message from
+ * @param cls client we received this message from
  * @param message the actual message received
  *
  */
 static void
 handle_dht_local_get_stop (void *cls,
-                           struct GNUNET_SERVER_Client *client,
-                           const struct GNUNET_MessageHeader *message)
+                           const struct GNUNET_DHT_ClientGetStopMessage *dht_stop_msg)
 {
-  const struct GNUNET_DHT_ClientGetStopMessage *dht_stop_msg =
-      (const struct GNUNET_DHT_ClientGetStopMessage *) message;
+  struct ClientHandle *ch = cls;
   struct RemoveByUniqueIdContext ctx;
 
   GNUNET_STATISTICS_update (GDS_stats,
@@ -803,179 +791,98 @@ handle_dht_local_get_stop (void *cls,
   LOG (GNUNET_ERROR_TYPE_DEBUG,
        "Received GET STOP request for %s from local client %p\n",
        GNUNET_h2s (&dht_stop_msg->key),
-       client);
-  ctx.client = find_active_client (client);
+       ch->client);
+  ctx.ch = ch;
   ctx.unique_id = dht_stop_msg->unique_id;
-  GNUNET_CONTAINER_multihashmap_get_multiple (forward_map, &dht_stop_msg->key,
-                                              &remove_by_unique_id, &ctx);
-  GNUNET_SERVER_receive_done (client, GNUNET_OK);
+  GNUNET_CONTAINER_multihashmap_get_multiple (forward_map,
+                                              &dht_stop_msg->key,
+                                              &remove_by_unique_id,
+                                              &ctx);
+  GNUNET_SERVICE_client_continue (ch->client);
 }
 
 
 /**
  * Handler for monitor start messages
  *
- * @param cls closure for the service
- * @param client the client we received this message from
- * @param message the actual message received
+ * @param cls the client we received this message from
+ * @param msg the actual message received
  *
  */
 static void
-handle_dht_local_monitor (void *cls, struct GNUNET_SERVER_Client *client,
-                          const struct GNUNET_MessageHeader *message)
+handle_dht_local_monitor (void *cls,
+                          const struct GNUNET_DHT_MonitorStartStopMessage *msg)
 {
+  struct ClientHandle *ch = cls;
   struct ClientMonitorRecord *r;
-  const struct GNUNET_DHT_MonitorStartStopMessage *msg;
 
-  msg = (struct GNUNET_DHT_MonitorStartStopMessage *) message;
   r = GNUNET_new (struct ClientMonitorRecord);
-
-  r->client = find_active_client(client);
-  r->type = ntohl(msg->type);
-  r->get = ntohs(msg->get);
-  r->get_resp = ntohs(msg->get_resp);
-  r->put = ntohs(msg->put);
-  if (0 == ntohs(msg->filter_key))
-      r->key = NULL;
+  r->ch = ch;
+  r->type = ntohl (msg->type);
+  r->get = ntohs (msg->get);
+  r->get_resp = ntohs (msg->get_resp);
+  r->put = ntohs (msg->put);
+  if (0 == ntohs (msg->filter_key))
+  {
+    r->key = NULL;
+  }
   else
   {
     r->key = GNUNET_new (struct GNUNET_HashCode);
-    GNUNET_memcpy (r->key, &msg->key, sizeof (struct GNUNET_HashCode));
+    GNUNET_memcpy (r->key,
+                   &msg->key,
+                   sizeof (struct GNUNET_HashCode));
   }
-  GNUNET_CONTAINER_DLL_insert (monitor_head, monitor_tail, r);
-  GNUNET_SERVER_receive_done (client, GNUNET_OK);
+  GNUNET_CONTAINER_DLL_insert (monitor_head,
+                               monitor_tail,
+                               r);
+  GNUNET_SERVICE_client_continue (ch->client);
 }
 
 
 /**
  * Handler for monitor stop messages
  *
- * @param cls closure for the service
- * @param client the client we received this message from
- * @param message the actual message received
- *
+ * @param cls the client we received this message from
+ * @param msg the actual message received
  */
 static void
-handle_dht_local_monitor_stop (void *cls, struct GNUNET_SERVER_Client *client,
-                               const struct GNUNET_MessageHeader *message)
+handle_dht_local_monitor_stop (void *cls,
+                               const struct GNUNET_DHT_MonitorStartStopMessage *msg)
 {
+  struct ClientHandle *ch = cls;
   struct ClientMonitorRecord *r;
-  const struct GNUNET_DHT_MonitorStartStopMessage *msg;
   int keys_match;
 
-  msg = (struct GNUNET_DHT_MonitorStartStopMessage *) message;
-  r = monitor_head;
-
-  while (NULL != r)
+  GNUNET_SERVICE_client_continue (ch->client);
+  for (r = monitor_head; NULL != r; r = r->next)
   {
     if (NULL == r->key)
-        keys_match = (0 == ntohs(msg->filter_key));
+    {
+      keys_match = (0 == ntohs(msg->filter_key));
+    }
     else
     {
-        keys_match = (0 != ntohs(msg->filter_key)
-                      && !memcmp(r->key, &msg->key, sizeof(struct GNUNET_HashCode)));
+      keys_match = ( (0 != ntohs(msg->filter_key)) &&
+                     (! memcmp (r->key,
+                                &msg->key,
+                                sizeof(struct GNUNET_HashCode))) );
     }
-    if (find_active_client(client) == r->client
-        && ntohl(msg->type) == r->type
-        && r->get == msg->get
-        && r->get_resp == msg->get_resp
-        && r->put == msg->put
-        && keys_match
-        )
+    if ( (ch == r->ch) &&
+         (ntohl(msg->type) == r->type) &&
+         (r->get == msg->get) &&
+         (r->get_resp == msg->get_resp) &&
+         (r->put == msg->put) &&
+         keys_match )
     {
-        GNUNET_CONTAINER_DLL_remove (monitor_head, monitor_tail, r);
-        GNUNET_free_non_null (r->key);
-        GNUNET_free (r);
-        GNUNET_SERVER_receive_done (client, GNUNET_OK);
-        return; /* Delete only ONE entry */
+      GNUNET_CONTAINER_DLL_remove (monitor_head,
+                                   monitor_tail,
+                                   r);
+      GNUNET_free_non_null (r->key);
+      GNUNET_free (r);
+      return; /* Delete only ONE entry */
     }
-    r = r->next;
   }
-
-  GNUNET_SERVER_receive_done (client, GNUNET_OK);
-}
-
-
-/**
- * Callback called as a result of issuing a GNUNET_SERVER_notify_transmit_ready
- * request.  A ClientList is passed as closure, take the head of the list
- * and copy it into buf, which has the result of sending the message to the
- * client.
- *
- * @param cls closure to this call
- * @param size maximum number of bytes available to send
- * @param buf where to copy the actual message to
- *
- * @return the number of bytes actually copied, 0 indicates failure
- */
-static size_t
-send_reply_to_client (void *cls, size_t size, void *buf)
-{
-  struct ClientList *client = cls;
-  char *cbuf = buf;
-  struct PendingMessage *reply;
-  size_t off;
-  size_t msize;
-
-  client->transmit_handle = NULL;
-  if (buf == NULL)
-  {
-    /* client disconnected */
-    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-                "Client %p disconnected, pending messages will be discarded\n",
-                client->client_handle);
-    return 0;
-  }
-  off = 0;
-  while ((NULL != (reply = client->pending_head)) &&
-         (size >= off + (msize = ntohs (reply->msg->size))))
-  {
-    GNUNET_CONTAINER_DLL_remove (client->pending_head, client->pending_tail,
-                                 reply);
-    GNUNET_memcpy (&cbuf[off], reply->msg, msize);
-    GNUNET_free (reply);
-    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-                "Transmitting %u bytes to client %p\n",
-                (unsigned int) msize,
-                client->client_handle);
-    off += msize;
-  }
-  process_pending_messages (client);
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              "Transmitted %u/%u bytes to client %p\n",
-              (unsigned int) off,
-              (unsigned int) size,
-              client->client_handle);
-  return off;
-}
-
-
-/**
- * Task run to check for messages that need to be sent to a client.
- *
- * @param client a ClientList, containing the client and any messages to be sent to it
- */
-static void
-process_pending_messages (struct ClientList *client)
-{
-  if ((client->pending_head == NULL) || (client->transmit_handle != NULL))
-  {
-    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-                "Not asking for transmission to %p now: %s\n",
-                client->client_handle,
-                client->pending_head ==
-                NULL ? "no more messages" : "request already pending");
-    return;
-  }
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              "Asking for transmission of %u bytes to client %p\n",
-              ntohs (client->pending_head->msg->size), client->client_handle);
-  client->transmit_handle =
-      GNUNET_SERVER_notify_transmit_ready (client->client_handle,
-                                           ntohs (client->pending_head->
-                                                  msg->size),
-                                           GNUNET_TIME_UNIT_FOREVER_REL,
-                                           &send_reply_to_client, client);
 }
 
 
@@ -986,19 +893,24 @@ struct ForwardReplyContext
 {
 
   /**
-   * Actual message to send to matching clients.
+   * Expiration time of the reply.
    */
-  struct PendingMessage *pm;
+  struct GNUNET_TIME_Absolute expiration;
 
   /**
-   * Embedded payload.
+   * GET path taken.
    */
-  const void *data;
+  const struct GNUNET_PeerIdentity *get_path;
 
   /**
-   * Type of the data.
+   * PUT path taken.
    */
-  enum GNUNET_BLOCK_Type type;
+  const struct GNUNET_PeerIdentity *put_path;
+
+  /**
+   * Embedded payload.
+   */
+  const void *data;
 
   /**
    * Number of bytes in data.
@@ -1006,9 +918,19 @@ struct ForwardReplyContext
   size_t data_size;
 
   /**
-   * Do we need to copy @a pm because it was already used?
+   * Number of entries in @e get_path.
    */
-  int do_copy;
+  unsigned int get_path_length;
+
+  /**
+   * Number of entries in @e put_path.
+   */
+  unsigned int put_path_length;
+
+  /**
+   * Type of the data.
+   */
+  enum GNUNET_BLOCK_Type type;
 
 };
 
@@ -1031,17 +953,18 @@ forward_reply (void *cls,
 {
   struct ForwardReplyContext *frc = cls;
   struct ClientQueryRecord *record = value;
-  struct PendingMessage *pm;
+  struct GNUNET_MQ_Envelope *env;
   struct GNUNET_DHT_ClientResultMessage *reply;
   enum GNUNET_BLOCK_EvaluationResult eval;
   int do_free;
   struct GNUNET_HashCode ch;
-  unsigned int i;
+  struct GNUNET_PeerIdentity *paths;
 
   LOG_TRAFFIC (GNUNET_ERROR_TYPE_DEBUG,
-               "R5N CLIENT-RESULT %s\n",
+               "CLIENT-RESULT %s\n",
                GNUNET_h2s_full (key));
-  if ((record->type != GNUNET_BLOCK_TYPE_ANY) && (record->type != frc->type))
+  if ( (record->type != GNUNET_BLOCK_TYPE_ANY) &&
+       (record->type != frc->type))
   {
     LOG (GNUNET_ERROR_TYPE_DEBUG,
          "Record type missmatch, not passing request for key %s to local client\n",
@@ -1053,8 +976,10 @@ forward_reply (void *cls,
     return GNUNET_YES;          /* type mismatch */
   }
   GNUNET_CRYPTO_hash (frc->data, frc->data_size, &ch);
-  for (i = 0; i < record->seen_replies_count; i++)
-    if (0 == memcmp (&record->seen_replies[i], &ch, sizeof (struct GNUNET_HashCode)))
+  for (unsigned int i = 0; i < record->seen_replies_count; i++)
+    if (0 == memcmp (&record->seen_replies[i],
+                     &ch,
+                     sizeof (struct GNUNET_HashCode)))
     {
       LOG (GNUNET_ERROR_TYPE_DEBUG,
            "Duplicate reply, not passing request for key %s to local client\n",
@@ -1065,8 +990,8 @@ forward_reply (void *cls,
                                 1, GNUNET_NO);
       return GNUNET_YES;        /* duplicate */
     }
-  eval =
-      GNUNET_BLOCK_evaluate (GDS_block_context,
+  eval
+    = GNUNET_BLOCK_evaluate (GDS_block_context,
                              record->type,
                              GNUNET_BLOCK_EO_NONE,
                              key,
@@ -1086,7 +1011,9 @@ forward_reply (void *cls,
     do_free = GNUNET_YES;
     break;
   case GNUNET_BLOCK_EVALUATION_OK_MORE:
-    GNUNET_array_append (record->seen_replies, record->seen_replies_count, ch);
+    GNUNET_array_append (record->seen_replies,
+                         record->seen_replies_count,
+                         ch);
     do_free = GNUNET_NO;
     break;
   case GNUNET_BLOCK_EVALUATION_OK_DUPLICATE:
@@ -1112,34 +1039,38 @@ forward_reply (void *cls,
     GNUNET_break (0);
     return GNUNET_NO;
   }
-  if (GNUNET_NO == frc->do_copy)
-  {
-    /* first time, we can use the original data */
-    pm = frc->pm;
-    frc->do_copy = GNUNET_YES;
-  }
-  else
-  {
-    /* two clients waiting for same reply, must copy for queueing */
-    pm = GNUNET_malloc (sizeof (struct PendingMessage) +
-                        ntohs (frc->pm->msg->size));
-    GNUNET_memcpy (pm, frc->pm,
-            sizeof (struct PendingMessage) + ntohs (frc->pm->msg->size));
-    pm->next = pm->prev = NULL;
-    pm->msg = (struct GNUNET_MessageHeader *) &pm[1];
-  }
   GNUNET_STATISTICS_update (GDS_stats,
-                            gettext_noop ("# RESULTS queued for clients"), 1,
+                            gettext_noop ("# RESULTS queued for clients"),
+                            1,
                             GNUNET_NO);
-  reply = (struct GNUNET_DHT_ClientResultMessage *) &pm[1];
+  env = GNUNET_MQ_msg_extra (reply,
+                             frc->data_size +
+                             (frc->get_path_length + frc->put_path_length) * sizeof (struct GNUNET_PeerIdentity),
+                             GNUNET_MESSAGE_TYPE_DHT_CLIENT_RESULT);
+  reply->type = htonl (frc->type);
+  reply->get_path_length = htonl (frc->get_path_length);
+  reply->put_path_length = htonl (frc->put_path_length);
   reply->unique_id = record->unique_id;
+  reply->expiration = GNUNET_TIME_absolute_hton (frc->expiration);
+  reply->key = *key;
+  paths = (struct GNUNET_PeerIdentity *) &reply[1];
+  GNUNET_memcpy (paths,
+                 frc->put_path,
+                 sizeof (struct GNUNET_PeerIdentity) * frc->put_path_length);
+  GNUNET_memcpy (&paths[frc->put_path_length],
+                 frc->get_path,
+                 sizeof (struct GNUNET_PeerIdentity) * frc->get_path_length);
+  GNUNET_memcpy (&paths[frc->get_path_length + frc->put_path_length],
+                 frc->data,
+                 frc->data_size);
   LOG (GNUNET_ERROR_TYPE_DEBUG,
-       "Queueing reply to query %s for client %p\n",
+       "Sending reply to query %s for client %p\n",
        GNUNET_h2s (key),
-       record->client->client_handle);
-  add_pending_message (record->client, pm);
+       record->ch->client);
+  GNUNET_MQ_send (record->ch->mq,
+                  env);
   if (GNUNET_YES == do_free)
-    remove_client_records (record->client, key, record);
+    remove_client_record (record);
   return GNUNET_YES;
 }
 
@@ -1166,74 +1097,48 @@ GDS_CLIENTS_handle_reply (struct GNUNET_TIME_Absolute expiration,
                           const struct GNUNET_PeerIdentity *get_path,
                           unsigned int put_path_length,
                           const struct GNUNET_PeerIdentity *put_path,
-                          enum GNUNET_BLOCK_Type type, size_t data_size,
+                          enum GNUNET_BLOCK_Type type,
+                          size_t data_size,
                           const void *data)
 {
   struct ForwardReplyContext frc;
-  struct PendingMessage *pm;
-  struct GNUNET_DHT_ClientResultMessage *reply;
-  struct GNUNET_PeerIdentity *paths;
   size_t msize;
 
-  if (NULL == GNUNET_CONTAINER_multihashmap_get (forward_map, key))
+  msize = sizeof (struct GNUNET_DHT_ClientResultMessage) + data_size +
+    (get_path_length + put_path_length) * sizeof (struct GNUNET_PeerIdentity);
+  if (msize >= GNUNET_SERVER_MAX_MESSAGE_SIZE)
+  {
+    GNUNET_break (0);
+    return;
+  }
+  if (NULL == GNUNET_CONTAINER_multihashmap_get (forward_map,
+                                                 key))
   {
     LOG (GNUNET_ERROR_TYPE_DEBUG,
          "No matching client for reply for key %s\n",
          GNUNET_h2s (key));
     GNUNET_STATISTICS_update (GDS_stats,
-                              gettext_noop
-                              ("# REPLIES ignored for CLIENTS (no match)"), 1,
+                              gettext_noop ("# REPLIES ignored for CLIENTS (no match)"),
+                              1,
                               GNUNET_NO);
     return;                     /* no matching request, fast exit! */
   }
-  msize =
-      sizeof (struct GNUNET_DHT_ClientResultMessage) + data_size +
-      (get_path_length + put_path_length) * sizeof (struct GNUNET_PeerIdentity);
-  if (msize >= GNUNET_SERVER_MAX_MESSAGE_SIZE)
-  {
-    GNUNET_break (0);
-    return;
-  }
-  LOG (GNUNET_ERROR_TYPE_DEBUG,
-       "Forwarding reply for key %s to client\n",
-       GNUNET_h2s (key));
-
-  pm = GNUNET_malloc (msize + sizeof (struct PendingMessage));
-  reply = (struct GNUNET_DHT_ClientResultMessage *) &pm[1];
-  pm->msg = &reply->header;
-  reply->header.size = htons ((uint16_t) msize);
-  reply->header.type = htons (GNUNET_MESSAGE_TYPE_DHT_CLIENT_RESULT);
-  reply->type = htonl (type);
-  reply->get_path_length = htonl (get_path_length);
-  reply->put_path_length = htonl (put_path_length);
-  reply->unique_id = 0;         /* filled in later */
-  reply->expiration = GNUNET_TIME_absolute_hton (expiration);
-  reply->key = *key;
-  paths = (struct GNUNET_PeerIdentity *) &reply[1];
-  GNUNET_memcpy (paths, put_path,
-          sizeof (struct GNUNET_PeerIdentity) * put_path_length);
-  GNUNET_memcpy (&paths[put_path_length], get_path,
-          sizeof (struct GNUNET_PeerIdentity) * get_path_length);
-  GNUNET_memcpy (&paths[get_path_length + put_path_length], data, data_size);
-  frc.do_copy = GNUNET_NO;
-  frc.pm = pm;
+  frc.expiration = expiration;
+  frc.get_path = get_path;
+  frc.put_path = put_path;
   frc.data = data;
   frc.data_size = data_size;
+  frc.get_path_length = get_path_length;
+  frc.put_path_length = put_path_length;
   frc.type = type;
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Forwarding reply for key %s to client\n",
+       GNUNET_h2s (key));
   GNUNET_CONTAINER_multihashmap_get_multiple (forward_map,
                                               key,
                                               &forward_reply,
                                               &frc);
 
-  if (GNUNET_NO == frc.do_copy)
-  {
-    /* did not match any of the requests, free! */
-    GNUNET_STATISTICS_update (GDS_stats,
-                              gettext_noop
-                              ("# REPLIES ignored for CLIENTS (no match)"), 1,
-                              GNUNET_NO);
-    GNUNET_free (pm);
-  }
 }
 
 
@@ -1259,18 +1164,21 @@ GDS_CLIENTS_process_get (uint32_t options,
                          const struct GNUNET_HashCode * key)
 {
   struct ClientMonitorRecord *m;
-  struct ClientList **cl;
+  struct ClientHandle **cl;
   unsigned int cl_size;
 
   cl = NULL;
   cl_size = 0;
   for (m = monitor_head; NULL != m; m = m->next)
   {
-    if ((GNUNET_BLOCK_TYPE_ANY == m->type || m->type == type) &&
-        (NULL == m->key ||
-         memcmp (key, m->key, sizeof(struct GNUNET_HashCode)) == 0))
+    if ( ( (GNUNET_BLOCK_TYPE_ANY == m->type) ||
+           (m->type == type) ) &&
+         ( (NULL == m->key) ||
+           (0 == memcmp (key,
+                         m->key,
+                         sizeof(struct GNUNET_HashCode))) ) )
     {
-      struct PendingMessage *pm;
+      struct GNUNET_MQ_Envelope *env;
       struct GNUNET_DHT_MonitorGetMessage *mmsg;
       struct GNUNET_PeerIdentity *msg_path;
       size_t msize;
@@ -1278,31 +1186,30 @@ GDS_CLIENTS_process_get (uint32_t options,
 
       /* Don't send duplicates */
       for (i = 0; i < cl_size; i++)
-        if (cl[i] == m->client)
+        if (cl[i] == m->ch)
           break;
       if (i < cl_size)
         continue;
-      GNUNET_array_append (cl, cl_size, m->client);
+      GNUNET_array_append (cl,
+                           cl_size,
+                           m->ch);
 
       msize = path_length * sizeof (struct GNUNET_PeerIdentity);
-      msize += sizeof (struct GNUNET_DHT_MonitorGetMessage);
-      msize += sizeof (struct PendingMessage);
-      pm = GNUNET_malloc (msize);
-      mmsg = (struct GNUNET_DHT_MonitorGetMessage *) &pm[1];
-      pm->msg = &mmsg->header;
-      mmsg->header.size = htons (msize - sizeof (struct PendingMessage));
-      mmsg->header.type = htons (GNUNET_MESSAGE_TYPE_DHT_MONITOR_GET);
+      env = GNUNET_MQ_msg_extra (mmsg,
+                                 msize,
+                                 GNUNET_MESSAGE_TYPE_DHT_MONITOR_GET);
       mmsg->options = htonl(options);
       mmsg->type = htonl(type);
       mmsg->hop_count = htonl(hop_count);
       mmsg->desired_replication_level = htonl(desired_replication_level);
       mmsg->get_path_length = htonl(path_length);
-      GNUNET_memcpy (&mmsg->key, key, sizeof (struct GNUNET_HashCode));
+      mmsg->key = *key;
       msg_path = (struct GNUNET_PeerIdentity *) &mmsg[1];
-      if (path_length > 0)
-        GNUNET_memcpy (msg_path, path,
-                path_length * sizeof (struct GNUNET_PeerIdentity));
-      add_pending_message (m->client, pm);
+      GNUNET_memcpy (msg_path,
+                     path,
+                     path_length * sizeof (struct GNUNET_PeerIdentity));
+      GNUNET_MQ_send (m->ch->mq,
+                      env);
     }
   }
   GNUNET_free_non_null (cl);
@@ -1335,7 +1242,7 @@ GDS_CLIENTS_process_get_resp (enum GNUNET_BLOCK_Type type,
                               size_t size)
 {
   struct ClientMonitorRecord *m;
-  struct ClientList **cl;
+  struct ClientHandle **cl;
   unsigned int cl_size;
 
   cl = NULL;
@@ -1346,7 +1253,7 @@ GDS_CLIENTS_process_get_resp (enum GNUNET_BLOCK_Type type,
         (NULL == m->key ||
          memcmp (key, m->key, sizeof(struct GNUNET_HashCode)) == 0))
     {
-      struct PendingMessage *pm;
+      struct GNUNET_MQ_Envelope *env;
       struct GNUNET_DHT_MonitorGetRespMessage *mmsg;
       struct GNUNET_PeerIdentity *path;
       size_t msize;
@@ -1354,40 +1261,37 @@ GDS_CLIENTS_process_get_resp (enum GNUNET_BLOCK_Type type,
 
       /* Don't send duplicates */
       for (i = 0; i < cl_size; i++)
-        if (cl[i] == m->client)
+        if (cl[i] == m->ch)
           break;
       if (i < cl_size)
         continue;
-      GNUNET_array_append (cl, cl_size, m->client);
+      GNUNET_array_append (cl,
+                           cl_size,
+                           m->ch);
 
       msize = size;
       msize += (get_path_length + put_path_length)
                * sizeof (struct GNUNET_PeerIdentity);
-      msize += sizeof (struct GNUNET_DHT_MonitorGetRespMessage);
-      msize += sizeof (struct PendingMessage);
-      pm = GNUNET_malloc (msize);
-      mmsg = (struct GNUNET_DHT_MonitorGetRespMessage *) &pm[1];
-      pm->msg = (struct GNUNET_MessageHeader *) mmsg;
-      mmsg->header.size = htons (msize - sizeof (struct PendingMessage));
-      mmsg->header.type = htons (GNUNET_MESSAGE_TYPE_DHT_MONITOR_GET_RESP);
+      env = GNUNET_MQ_msg_extra (mmsg,
+                                 msize,
+                                 GNUNET_MESSAGE_TYPE_DHT_MONITOR_GET_RESP);
       mmsg->type = htonl(type);
       mmsg->put_path_length = htonl(put_path_length);
       mmsg->get_path_length = htonl(get_path_length);
-      path = (struct GNUNET_PeerIdentity *) &mmsg[1];
-      if (put_path_length > 0)
-      {
-        GNUNET_memcpy (path, put_path,
-                put_path_length * sizeof (struct GNUNET_PeerIdentity));
-        path = &path[put_path_length];
-      }
-      if (get_path_length > 0)
-        GNUNET_memcpy (path, get_path,
-                get_path_length * sizeof (struct GNUNET_PeerIdentity));
       mmsg->expiration_time = GNUNET_TIME_absolute_hton(exp);
-      GNUNET_memcpy (&mmsg->key, key, sizeof (struct GNUNET_HashCode));
-      if (size > 0)
-        GNUNET_memcpy (&path[get_path_length], data, size);
-      add_pending_message (m->client, pm);
+      mmsg->key = *key;
+      path = (struct GNUNET_PeerIdentity *) &mmsg[1];
+      GNUNET_memcpy (path,
+                     put_path,
+                     put_path_length * sizeof (struct GNUNET_PeerIdentity));
+      GNUNET_memcpy (path,
+                     get_path,
+                     get_path_length * sizeof (struct GNUNET_PeerIdentity));
+      GNUNET_memcpy (&path[get_path_length],
+                     data,
+                     size);
+      GNUNET_MQ_send (m->ch->mq,
+                      env);
     }
   }
   GNUNET_free_non_null (cl);
@@ -1422,7 +1326,7 @@ GDS_CLIENTS_process_put (uint32_t options,
                          size_t size)
 {
   struct ClientMonitorRecord *m;
-  struct ClientList **cl;
+  struct ClientHandle **cl;
   unsigned int cl_size;
 
   cl = NULL;
@@ -1433,7 +1337,7 @@ GDS_CLIENTS_process_put (uint32_t options,
         (NULL == m->key ||
          memcmp (key, m->key, sizeof(struct GNUNET_HashCode)) == 0))
     {
-      struct PendingMessage *pm;
+      struct GNUNET_MQ_Envelope *env;
       struct GNUNET_DHT_MonitorPutMessage *mmsg;
       struct GNUNET_PeerIdentity *msg_path;
       size_t msize;
@@ -1441,38 +1345,35 @@ GDS_CLIENTS_process_put (uint32_t options,
 
       /* Don't send duplicates */
       for (i = 0; i < cl_size; i++)
-        if (cl[i] == m->client)
+        if (cl[i] == m->ch)
           break;
       if (i < cl_size)
         continue;
-      GNUNET_array_append (cl, cl_size, m->client);
+      GNUNET_array_append (cl,
+                           cl_size,
+                           m->ch);
 
       msize = size;
       msize += path_length * sizeof (struct GNUNET_PeerIdentity);
-      msize += sizeof (struct GNUNET_DHT_MonitorPutMessage);
-      msize += sizeof (struct PendingMessage);
-      pm = GNUNET_malloc (msize);
-      mmsg = (struct GNUNET_DHT_MonitorPutMessage *) &pm[1];
-      pm->msg = (struct GNUNET_MessageHeader *) mmsg;
-      mmsg->header.size = htons (msize - sizeof (struct PendingMessage));
-      mmsg->header.type = htons (GNUNET_MESSAGE_TYPE_DHT_MONITOR_PUT);
+      env = GNUNET_MQ_msg_extra (mmsg,
+                                 msize,
+                                 GNUNET_MESSAGE_TYPE_DHT_MONITOR_PUT);
       mmsg->options = htonl(options);
       mmsg->type = htonl(type);
       mmsg->hop_count = htonl(hop_count);
-      mmsg->desired_replication_level = htonl(desired_replication_level);
-      mmsg->put_path_length = htonl(path_length);
+      mmsg->desired_replication_level = htonl (desired_replication_level);
+      mmsg->put_path_length = htonl (path_length);
+      mmsg->key = *key;
+      mmsg->expiration_time = GNUNET_TIME_absolute_hton (exp);
       msg_path = (struct GNUNET_PeerIdentity *) &mmsg[1];
-      if (path_length > 0)
-      {
-        GNUNET_memcpy (msg_path,
-                       path,
-                       path_length * sizeof (struct GNUNET_PeerIdentity));
-      }
-      mmsg->expiration_time = GNUNET_TIME_absolute_hton(exp);
-      GNUNET_memcpy (&mmsg->key, key, sizeof (struct GNUNET_HashCode));
-      if (size > 0)
-        GNUNET_memcpy (&msg_path[path_length], data, size);
-      add_pending_message (m->client, pm);
+      GNUNET_memcpy (msg_path,
+                     path,
+                     path_length * sizeof (struct GNUNET_PeerIdentity));
+      GNUNET_memcpy (&msg_path[path_length],
+                     data,
+                     size);
+      GNUNET_MQ_send (m->ch->mq,
+                      env);
     }
   }
   GNUNET_free_non_null (cl);
@@ -1484,43 +1385,21 @@ GDS_CLIENTS_process_put (uint32_t options,
  *
  * @param server the initialized server
  */
-void
+static void
 GDS_CLIENTS_init ()
 {
-  static struct GNUNET_SERVER_MessageHandler plugin_handlers[] = {
-    {&handle_dht_local_put, NULL,
-     GNUNET_MESSAGE_TYPE_DHT_CLIENT_PUT, 0},
-    {&handle_dht_local_get, NULL,
-     GNUNET_MESSAGE_TYPE_DHT_CLIENT_GET, 0},
-    {&handle_dht_local_get_stop, NULL,
-     GNUNET_MESSAGE_TYPE_DHT_CLIENT_GET_STOP,
-     sizeof (struct GNUNET_DHT_ClientGetStopMessage)},
-    {&handle_dht_local_monitor, NULL,
-     GNUNET_MESSAGE_TYPE_DHT_MONITOR_START,
-     sizeof (struct GNUNET_DHT_MonitorStartStopMessage)},
-    {&handle_dht_local_monitor_stop, NULL,
-     GNUNET_MESSAGE_TYPE_DHT_MONITOR_STOP,
-     sizeof (struct GNUNET_DHT_MonitorStartStopMessage)},
-    {&handle_dht_local_get_result_seen, NULL,
-     GNUNET_MESSAGE_TYPE_DHT_CLIENT_GET_RESULTS_KNOWN, 0},
-    {NULL, NULL, 0, 0}
-  };
-
-  forward_map = GNUNET_CONTAINER_multihashmap_create (1024, GNUNET_NO);
-  retry_heap = GNUNET_CONTAINER_heap_create (GNUNET_CONTAINER_HEAP_ORDER_MIN);
-  GNUNET_SERVER_resume (GDS_server);
-  GNUNET_SERVER_add_handlers (GDS_server,
-                              plugin_handlers);
-  GNUNET_SERVER_disconnect_notify (GDS_server,
-                                   &handle_client_disconnect,
-                                   NULL);
+  forward_map
+    = GNUNET_CONTAINER_multihashmap_create (1024,
+                                            GNUNET_YES);
+  retry_heap
+    = GNUNET_CONTAINER_heap_create (GNUNET_CONTAINER_HEAP_ORDER_MIN);
 }
 
 
 /**
  * Shutdown client subsystem.
  */
-void
+static void
 GDS_CLIENTS_stop ()
 {
   if (NULL != retry_task)
@@ -1532,13 +1411,51 @@ GDS_CLIENTS_stop ()
 
 
 /**
- * Shutdown client subsystem.
+ * Define "main" method using service macro.
+ *
+ * @param run name of the initializaton method for the service
  */
-void
+#define GDS_DHT_SERVICE_INIT(run)   \
+ GNUNET_SERVICE_MAIN \
+  ("dht", \
+  GNUNET_SERVICE_OPTION_NONE, \
+  run, \
+  &client_connect_cb, \
+  &client_disconnect_cb, \
+  NULL, \
+  GNUNET_MQ_hd_var_size (dht_local_put, \
+                         GNUNET_MESSAGE_TYPE_DHT_CLIENT_PUT, \
+                         struct GNUNET_DHT_ClientPutMessage, \
+                         NULL), \
+  GNUNET_MQ_hd_var_size (dht_local_get, \
+                         GNUNET_MESSAGE_TYPE_DHT_CLIENT_GET, \
+                         struct GNUNET_DHT_ClientGetMessage, \
+                         NULL), \
+  GNUNET_MQ_hd_fixed_size (dht_local_get_stop, \
+                          GNUNET_MESSAGE_TYPE_DHT_CLIENT_GET_STOP, \
+                          struct GNUNET_DHT_ClientGetStopMessage, \
+                          NULL), \
+  GNUNET_MQ_hd_fixed_size (dht_local_monitor, \
+                           GNUNET_MESSAGE_TYPE_DHT_MONITOR_START, \
+                           struct GNUNET_DHT_MonitorStartStopMessage, \
+                           NULL), \
+  GNUNET_MQ_hd_fixed_size (dht_local_monitor_stop, \
+                           GNUNET_MESSAGE_TYPE_DHT_MONITOR_STOP, \
+                           struct GNUNET_DHT_MonitorStartStopMessage, \
+                           NULL), \
+  GNUNET_MQ_hd_var_size (dht_local_get_result_seen, \
+                         GNUNET_MESSAGE_TYPE_DHT_CLIENT_GET_RESULTS_KNOWN, \
+                         struct GNUNET_DHT_ClientGetResultSeenMessage , \
+                         NULL), \
+  GNUNET_MQ_handler_end ())
+
+
+/**
+ * MINIMIZE heap size (way below 128k) since this process doesn't need much.
+ */
+void __attribute__ ((destructor))
 GDS_CLIENTS_done ()
 {
-  GNUNET_assert (NULL == client_head);
-  GNUNET_assert (NULL == client_tail);
   if (NULL != retry_heap)
   {
     GNUNET_assert (0 == GNUNET_CONTAINER_heap_get_size (retry_heap));
diff --git a/src/dht/gnunet-service-dht_clients.h b/src/dht/gnunet-service-dht_clients.h
deleted file mode 100644
index 8a0931f6a..000000000
--- a/src/dht/gnunet-service-dht_clients.h
+++ /dev/null
@@ -1,153 +0,0 @@
-/*
-     This file is part of GNUnet.
-     Copyright (C) 2009, 2010, 2011 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
-     by the Free Software Foundation; either version 3, or (at your
-     option) any later version.
-
-     GNUnet is distributed in the hope that it will be useful, but
-     WITHOUT ANY WARRANTY; without even the implied warranty of
-     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-     General Public License for more details.
-
-     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., 51 Franklin Street, Fifth Floor,
-     Boston, MA 02110-1301, USA.
-*/
-
-/**
- * @file dht/gnunet-service-dht_clients.h
- * @brief GNUnet DHT service's client management code
- * @author Christian Grothoff
- * @author Nathan Evans
- */
-#ifndef GNUNET_SERVICE_DHT_CLIENT_H
-#define GNUNET_SERVICE_DHT_CLIENT_H
-
-#include "gnunet_util_lib.h"
-#include "gnunet_block_lib.h"
-
-/**
- * Handle a reply we've received from another peer.  If the reply
- * matches any of our pending queries, forward it to the respective
- * client(s).
- *
- * @param expiration when will the reply expire
- * @param key the query this reply is for
- * @param get_path_length number of peers in @a get_path
- * @param get_path path the reply took on get
- * @param put_path_length number of peers in @a put_path
- * @param put_path path the reply took on put
- * @param type type of the reply
- * @param data_size number of bytes in @a data
- * @param data application payload data
- */
-void
-GDS_CLIENTS_handle_reply (struct GNUNET_TIME_Absolute expiration,
-                          const struct GNUNET_HashCode *key,
-                          unsigned int get_path_length,
-                          const struct GNUNET_PeerIdentity *get_path,
-                          unsigned int put_path_length,
-                          const struct GNUNET_PeerIdentity *put_path,
-                          enum GNUNET_BLOCK_Type type, size_t data_size,
-                          const void *data);
-
-
-/**
- * Check if some client is monitoring GET messages and notify
- * them in that case.
- *
- * @param options Options, for instance RecordRoute, DemultiplexEverywhere.
- * @param type The type of data in the request.
- * @param hop_count Hop count so far.
- * @param path_length number of entries in path (or 0 if not recorded).
- * @param path peers on the GET path (or NULL if not recorded).
- * @param desired_replication_level Desired replication level.
- * @param key Key of the requested data.
- */
-void
-GDS_CLIENTS_process_get (uint32_t options,
-                         enum GNUNET_BLOCK_Type type,
-                         uint32_t hop_count,
-                         uint32_t desired_replication_level,
-                         unsigned int path_length,
-                         const struct GNUNET_PeerIdentity *path,
-                         const struct GNUNET_HashCode *key);
-
-
-/**
- * Check if some client is monitoring GET RESP messages and notify
- * them in that case.
- *
- * @param type The type of data in the result.
- * @param get_path Peers on GET path (or NULL if not recorded).
- * @param get_path_length number of entries in @a get_path.
- * @param put_path peers on the PUT path (or NULL if not recorded).
- * @param put_path_length number of entries in @a get_path.
- * @param exp Expiration time of the data.
- * @param key Key of the @a data.
- * @param data Pointer to the result data.
- * @param size Number of bytes in @a data.
- */
-void
-GDS_CLIENTS_process_get_resp (enum GNUNET_BLOCK_Type type,
-                              const struct GNUNET_PeerIdentity *get_path,
-                              unsigned int get_path_length,
-                              const struct GNUNET_PeerIdentity *put_path,
-                              unsigned int put_path_length,
-                              struct GNUNET_TIME_Absolute exp,
-                              const struct GNUNET_HashCode * key,
-                              const void *data,
-                              size_t size);
-
-
-/**
- * Check if some client is monitoring PUT messages and notify
- * them in that case.
- *
- * @param options Options, for instance RecordRoute, DemultiplexEverywhere.
- * @param type The type of data in the request.
- * @param hop_count Hop count so far.
- * @param path_length number of entries in path (or 0 if not recorded).
- * @param path peers on the PUT path (or NULL if not recorded).
- * @param desired_replication_level Desired replication level.
- * @param exp Expiration time of the data.
- * @param key Key under which data is to be stored.
- * @param data Pointer to the data carried.
- * @param size Number of bytes in data.
- */
-void
-GDS_CLIENTS_process_put (uint32_t options,
-                         enum GNUNET_BLOCK_Type type,
-                         uint32_t hop_count,
-                         uint32_t desired_replication_level,
-                         unsigned int path_length,
-                         const struct GNUNET_PeerIdentity *path,
-                         struct GNUNET_TIME_Absolute exp,
-                         const struct GNUNET_HashCode * key,
-                         const void *data,
-                         size_t size);
-
-/**
- * Initialize client subsystem.
- */
-void
-GDS_CLIENTS_init (void);
-
-/**
- * Shutdown client subsystem.
- */
-void
-GDS_CLIENTS_stop (void);
-
-
-/**
- * Shutdown client subsystem.
- */
-void
-GDS_CLIENTS_done (void);
-
-#endif
diff --git a/src/dht/gnunet-service-dht_datacache.c b/src/dht/gnunet-service-dht_datacache.c
index 322b5af17..12c79764d 100644
--- a/src/dht/gnunet-service-dht_datacache.c
+++ b/src/dht/gnunet-service-dht_datacache.c
@@ -25,7 +25,6 @@
  */
 #include "platform.h"
 #include "gnunet_datacache_lib.h"
-#include "gnunet-service-dht_clients.h"
 #include "gnunet-service-dht_datacache.h"
 #include "gnunet-service-dht_routing.h"
 #include "gnunet-service-dht.h"
diff --git a/src/dht/gnunet-service-dht_neighbours.c b/src/dht/gnunet-service-dht_neighbours.c
index 683e0991a..39fb43495 100644
--- a/src/dht/gnunet-service-dht_neighbours.c
+++ b/src/dht/gnunet-service-dht_neighbours.c
@@ -39,7 +39,6 @@
 #include "gnunet_dht_service.h"
 #include "gnunet_statistics_service.h"
 #include "gnunet-service-dht.h"
-#include "gnunet-service-dht_clients.h"
 #include "gnunet-service-dht_datacache.h"
 #include "gnunet-service-dht_hello.h"
 #include "gnunet-service-dht_neighbours.h"
@@ -1587,7 +1586,7 @@ core_init (void *cls,
   GNUNET_CRYPTO_hash (identity,
                       sizeof (struct GNUNET_PeerIdentity),
                       &my_identity_hash);
-  GDS_CLIENTS_init ();
+  GNUNET_SERVICE_resume (GDS_service);
 }