Merge branch 'master' of ssh://gnunet.org/gnunet
[oweals/gnunet.git] / src / set / gnunet-service-set.c
index 5e1b89936b6a38643edb2fbb435f28f21e0b24ed..b0f8b209186c1ee4a89036ddb2f04b06df2638bd 100644 (file)
@@ -1,6 +1,6 @@
 /*
       This file is part of GNUnet
-      (C) 2013, 2014 Christian Grothoff (and other contributing authors)
+      Copyright (C) 2013, 2014, 2017 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
@@ -14,8 +14,8 @@
 
       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 Temple Place - Suite 330,
-      Boston, MA 02111-1307, USA.
+      Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+      Boston, MA 02110-1301, USA.
 */
 /**
  * @file set/gnunet-service-set.c
@@ -24,7 +24,8 @@
  * @author Christian Grothoff
  */
 #include "gnunet-service-set.h"
-#include "set_protocol.h"
+#include "gnunet-service-set_protocol.h"
+#include "gnunet_statistics_service.h"
 
 /**
  * How long do we hold on to an incoming channel if there is
@@ -52,7 +53,7 @@ struct Listener
    * Client that owns the listener.
    * Only one client may own a listener.
    */
-  struct GNUNET_SERVER_Client *client;
+  struct GNUNET_SERVICE_Client *client;
 
   /**
    * Message queue for the client
@@ -65,6 +66,11 @@ struct Listener
    */
   struct GNUNET_HashCode app_id;
 
+  /**
+   * The port we are listening on with CADET.
+   */
+  struct GNUNET_CADET_Port *open_port;
+
   /**
    * The type of the operation.
    */
@@ -72,6 +78,16 @@ struct Listener
 };
 
 
+struct LazyCopyRequest
+{
+  struct Set *source_set;
+  uint32_t cookie;
+
+  struct LazyCopyRequest *prev;
+  struct LazyCopyRequest *next;
+};
+
+
 /**
  * Configuration of our local peer.
  */
@@ -115,6 +131,11 @@ static struct Operation *incoming_head;
  */
 static struct Operation *incoming_tail;
 
+static struct LazyCopyRequest *lazy_copy_head;
+static struct LazyCopyRequest *lazy_copy_tail;
+
+static uint32_t lazy_copy_cookie = 1;
+
 /**
  * Counter for allocating unique IDs for clients, used to identify
  * incoming operation requests from remote peers, that the client can
@@ -122,6 +143,11 @@ static struct Operation *incoming_tail;
  */
 static uint32_t suggest_id = 1;
 
+/**
+ * Statistics handle.
+ */
+struct GNUNET_STATISTICS_Handle *_GSS_statistics;
+
 
 /**
  * Get set that is owned by the given client, if any.
@@ -131,7 +157,7 @@ static uint32_t suggest_id = 1;
  *         does not own a set
  */
 static struct Set *
-set_get (struct GNUNET_SERVER_Client *client)
+set_get (struct GNUNET_SERVICE_Client *client)
 {
   struct Set *set;
 
@@ -150,7 +176,7 @@ set_get (struct GNUNET_SERVER_Client *client)
  *         if there isn't any
  */
 static struct Listener *
-listener_get (struct GNUNET_SERVER_Client *client)
+listener_get (struct GNUNET_SERVICE_Client *client)
 {
   struct Listener *listener;
 
@@ -195,19 +221,18 @@ listener_destroy (struct Listener *listener)
    * The client's destroy callback will destroy the listener again. */
   if (NULL != listener->client)
   {
-    struct GNUNET_SERVER_Client *client = listener->client;
+    struct GNUNET_SERVICE_Client *client = listener->client;
+
+    GNUNET_MQ_destroy (listener->client_mq);
+    listener->client_mq = NULL;
 
     listener->client = NULL;
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                 "Disconnecting listener client\n");
-    GNUNET_SERVER_client_disconnect (client);
+    GNUNET_SERVICE_client_drop (client);
     return;
   }
-  if (NULL != listener->client_mq)
-  {
-    GNUNET_MQ_destroy (listener->client_mq);
-    listener->client_mq = NULL;
-  }
+  GNUNET_CADET_close_port (listener->open_port);
   GNUNET_CONTAINER_DLL_remove (listeners_head,
                                listeners_tail,
                                listener);
@@ -253,20 +278,20 @@ garbage_collect_cb (void *cls,
                     const struct GNUNET_HashCode *key,
                     void *value)
 {
-  struct GarbageContext *gc = cls;
-  struct ElementEntry *ee = value;
-
-  if (GNUNET_YES != ee->removed)
-    return GNUNET_OK;
-  if ( (gc->max_op_generation < ee->generation_added) ||
-       (ee->generation_removed > gc->min_op_generation) )
-  {
-    GNUNET_assert (GNUNET_YES ==
-                   GNUNET_CONTAINER_multihashmap_remove (gc->map,
-                                                         key,
-                                                         ee));
-    GNUNET_free (ee);
-  }
+  //struct GarbageContext *gc = cls;
+  //struct ElementEntry *ee = value;
+
+  //if (GNUNET_YES != ee->removed)
+  //  return GNUNET_OK;
+  //if ( (gc->max_op_generation < ee->generation_added) ||
+  //     (ee->generation_removed > gc->min_op_generation) )
+  //{
+  //  GNUNET_assert (GNUNET_YES ==
+  //                 GNUNET_CONTAINER_multihashmap_remove (gc->map,
+  //                                                       key,
+  //                                                       ee));
+  //  GNUNET_free (ee);
+  //}
   return GNUNET_OK;
 }
 
@@ -293,13 +318,120 @@ collect_generation_garbage (struct Set *set)
     gc.max_op_generation = GNUNET_MAX (gc.max_op_generation,
                                        op->generation_created);
   }
-  gc.map = set->elements;
-  GNUNET_CONTAINER_multihashmap_iterate (set->elements,
+  gc.map = set->content->elements;
+  GNUNET_CONTAINER_multihashmap_iterate (set->content->elements,
                                          &garbage_collect_cb,
                                          &gc);
 }
 
 
+static int
+is_excluded_generation (unsigned int generation,
+                        struct GenerationRange *excluded,
+                        unsigned int excluded_size)
+{
+  unsigned int i;
+
+  for (i = 0; i < excluded_size; i++)
+  {
+    if ( (generation >= excluded[i].start) && (generation < excluded[i].end) )
+      return GNUNET_YES;
+  }
+
+  return GNUNET_NO;
+}
+
+
+static int
+is_element_of_generation (struct ElementEntry *ee,
+                          unsigned int query_generation,
+                          struct GenerationRange *excluded,
+                          unsigned int excluded_size)
+{
+  struct MutationEvent *mut;
+  int is_present;
+  unsigned int i;
+
+  GNUNET_assert (NULL != ee->mutations);
+
+  if (GNUNET_YES == is_excluded_generation (query_generation, excluded, excluded_size))
+  {
+    GNUNET_break (0);
+    return GNUNET_NO;
+  }
+
+  is_present = GNUNET_NO;
+
+  /* Could be made faster with binary search, but lists
+     are small, so why bother. */
+  for (i = 0; i < ee->mutations_size; i++)
+  {
+    mut = &ee->mutations[i];
+
+    if (mut->generation > query_generation)
+    {
+      /* The mutation doesn't apply to our generation
+         anymore.  We can'b break here, since mutations aren't
+         sorted by generation. */
+      continue;
+    }
+
+    if (GNUNET_YES == is_excluded_generation (mut->generation, excluded, excluded_size))
+    {
+      /* The generation is excluded (because it belongs to another
+         fork via a lazy copy) and thus mutations aren't considered
+         for membership testing. */
+      continue;
+    }
+
+    /* This would be an inconsistency in how we manage mutations. */
+    if ( (GNUNET_YES == is_present) && (GNUNET_YES == mut->added) )
+      GNUNET_assert (0);
+
+    /* Likewise. */
+    if ( (GNUNET_NO == is_present) && (GNUNET_NO == mut->added) )
+      GNUNET_assert (0);
+
+    is_present = mut->added;
+  }
+
+  return is_present;
+}
+
+
+int
+_GSS_is_element_of_set (struct ElementEntry *ee,
+                        struct Set *set)
+{
+  return is_element_of_generation (ee,
+                                   set->current_generation,
+                                   set->excluded_generations,
+                                   set->excluded_generations_size);
+}
+
+
+static int
+is_element_of_iteration (struct ElementEntry *ee,
+                         struct Set *set)
+{
+  return is_element_of_generation (ee,
+                                   set->iter_generation,
+                                   set->excluded_generations,
+                                   set->excluded_generations_size);
+}
+
+
+int
+_GSS_is_element_of_operation (struct ElementEntry *ee,
+                              struct Operation *op)
+{
+  return is_element_of_generation (ee,
+                                   op->generation_created,
+                                   op->spec->set->excluded_generations,
+                                   op->spec->set->excluded_generations_size);
+}
+
+
 /**
  * Destroy the given operation.  Call the implementation-specific
  * cancel function of the operation.  Disconnects from the remote
@@ -339,11 +471,6 @@ _GSS_operation_destroy (struct Operation *op,
     GNUNET_free (op->spec);
     op->spec = NULL;
   }
-  if (NULL != op->mq)
-  {
-    GNUNET_MQ_destroy (op->mq);
-    op->mq = NULL;
-  }
   if (NULL != (channel = op->channel))
   {
     op->channel = NULL;
@@ -371,6 +498,8 @@ destroy_elements_iterator (void *cls,
 {
   struct ElementEntry *ee = value;
 
+  GNUNET_free_non_null (ee->mutations);
+
   GNUNET_free (ee);
   return GNUNET_YES;
 }
@@ -390,10 +519,10 @@ set_destroy (struct Set *set)
      * callback will call `set_destroy()` again in this case.  We do
      * this so that the channel end handler still has a valid set handle
      * to destroy. */
-    struct GNUNET_SERVER_Client *client = set->client;
+    struct GNUNET_SERVICE_Client *client = set->client;
 
     set->client = NULL;
-    GNUNET_SERVER_client_disconnect (client);
+    GNUNET_SERVICE_client_drop (client);
     return;
   }
   GNUNET_assert (NULL != set->state);
@@ -401,62 +530,86 @@ set_destroy (struct Set *set)
     _GSS_operation_destroy (set->ops_head, GNUNET_NO);
   set->vt->destroy_set (set->state);
   set->state = NULL;
-  if (NULL != set->client_mq)
-  {
-    GNUNET_MQ_destroy (set->client_mq);
-    set->client_mq = NULL;
-  }
   if (NULL != set->iter)
   {
     GNUNET_CONTAINER_multihashmap_iterator_destroy (set->iter);
     set->iter = NULL;
+    set->iteration_id++;
   }
-  if (NULL != set->elements)
   {
-    GNUNET_CONTAINER_multihashmap_iterate (set->elements,
-                                           &destroy_elements_iterator,
-                                           NULL);
-    GNUNET_CONTAINER_multihashmap_destroy (set->elements);
-    set->elements = NULL;
+    struct SetContent *content;
+    struct PendingMutation *pm;
+    struct PendingMutation *pm_current;
+
+    content = set->content;
+
+    // discard any pending mutations that reference this set
+    pm = content->pending_mutations_head;
+    while (NULL != pm)
+    {
+      pm_current = pm;
+      pm = pm->next;
+      if (pm_current-> set == set)
+        GNUNET_CONTAINER_DLL_remove (content->pending_mutations_head,
+                                     content->pending_mutations_tail,
+                                     pm_current);
+
+    }
+
+    set->content = NULL;
+    GNUNET_assert (0 != content->refcount);
+    content->refcount -= 1;
+    if (0 == content->refcount)
+    {
+      GNUNET_assert (NULL != content->elements);
+      GNUNET_CONTAINER_multihashmap_iterate (content->elements,
+                                             &destroy_elements_iterator,
+                                             NULL);
+      GNUNET_CONTAINER_multihashmap_destroy (content->elements);
+      content->elements = NULL;
+      GNUNET_free (content);
+    }
   }
+  GNUNET_free_non_null (set->excluded_generations);
+  set->excluded_generations = NULL;
   GNUNET_CONTAINER_DLL_remove (sets_head,
                                sets_tail,
                                set);
+
+  // remove set from pending copy requests
+  {
+    struct LazyCopyRequest *lcr;
+    lcr = lazy_copy_head;
+    while (NULL != lcr)
+    {
+      struct LazyCopyRequest *lcr_current;
+      lcr_current = lcr;
+      lcr = lcr->next;
+      if (lcr_current->source_set == set)
+        GNUNET_CONTAINER_DLL_remove (lazy_copy_head,
+                                     lazy_copy_tail,
+                                     lcr_current);
+    }
+  }
+
   GNUNET_free (set);
 }
 
 
 /**
- * Clean up after a client has disconnected
+ * Callback called when a client connects to the service.
  *
- * @param cls closure, unused
- * @param client the client to clean up after
+ * @param cls closure for the service
+ * @param c the new client that connected to the service
+ * @param mq the message queue used to send messages to the client
+ * @return @a c
  */
-static void
-handle_client_disconnect (void *cls,
-                          struct GNUNET_SERVER_Client *client)
+static void *
+client_connect_cb (void *cls,
+                  struct GNUNET_SERVICE_Client *c,
+                  struct GNUNET_MQ_Handle *mq)
 {
-  struct Set *set;
-  struct Listener *listener;
-
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              "client disconnected, cleaning up\n");
-  set = set_get (client);
-  if (NULL != set)
-  {
-    set->client = NULL;
-    set_destroy (set);
-    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-                "Client's set destroyed\n");
-  }
-  listener = listener_get (client);
-  if (NULL != listener)
-  {
-    listener->client = NULL;
-    listener_destroy (listener);
-    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-                "Client's listener destroyed\n");
-  }
+  return c;
 }
 
 
@@ -468,14 +621,16 @@ handle_client_disconnect (void *cls,
 static void
 incoming_destroy (struct Operation *incoming)
 {
+  struct GNUNET_CADET_Channel *channel;
+
   GNUNET_assert (GNUNET_YES == incoming->is_incoming);
   GNUNET_CONTAINER_DLL_remove (incoming_head,
                                incoming_tail,
                                incoming);
-  if (GNUNET_SCHEDULER_NO_TASK != incoming->timeout_task)
+  if (NULL != incoming->timeout_task)
   {
     GNUNET_SCHEDULER_cancel (incoming->timeout_task);
-    incoming->timeout_task = GNUNET_SCHEDULER_NO_TASK;
+    incoming->timeout_task = NULL;
   }
   /* make sure that the tunnel end handler will not destroy us again */
   incoming->vt = NULL;
@@ -484,39 +639,57 @@ incoming_destroy (struct Operation *incoming)
     GNUNET_free (incoming->spec);
     incoming->spec = NULL;
   }
-  if (NULL != incoming->mq)
-  {
-    GNUNET_MQ_destroy (incoming->mq);
-    incoming->mq = NULL;
-  }
-  if (NULL != incoming->channel)
+  if (NULL != (channel = incoming->channel))
   {
-    GNUNET_CADET_channel_destroy (incoming->channel);
     incoming->channel = NULL;
+    GNUNET_CADET_channel_destroy (channel);
   }
 }
 
 
 /**
- * Find a listener that is interested in the given operation type
- * and application id.
+ * Clean up after a client has disconnected
  *
- * @param op operation type to look for
- * @param app_id application id to look for
- * @return a matching listener, or NULL if no listener matches the
- *         given operation and application id
+ * @param cls closure, unused
+ * @param client the client to clean up after
+ * @param internal_cls our client-specific internal data structure
  */
-static struct Listener *
-listener_get_by_target (enum GNUNET_SET_OperationType op,
-                        const struct GNUNET_HashCode *app_id)
+static void
+client_disconnect_cb (void *cls,
+                      struct GNUNET_SERVICE_Client *client,
+                      void *internal_cls)
 {
-  struct Listener *listener;
+  struct Set *set;
 
-  for (listener = listeners_head; NULL != listener; listener = listener->next)
-    if ( (listener->operation == op) &&
-         (0 == GNUNET_CRYPTO_hash_cmp (app_id, &listener->app_id)) )
-      return listener;
-  return NULL;
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "client disconnected, cleaning up\n");
+  set = set_get (client);
+  if (NULL != set)
+  {
+    set->client = NULL;
+    set_destroy (set);
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Client's set destroyed\n");
+  }
+  struct Listener *listener = listener_get (client);
+  struct Operation *op = incoming_head;
+  if (NULL != listener)
+  {
+    /* destroy all incoming operations whose client just
+     * got destroyed */
+    while (NULL != op)
+    {
+      struct Operation *curr = op;
+      op = op->next;
+      if ( (GNUNET_YES == curr->is_incoming) && 
+           (curr->listener == listener) )
+        incoming_destroy (curr);
+    }
+    listener->client = NULL;
+    listener_destroy (listener);
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Client's listener destroyed\n");
+  }
 }
 
 
@@ -540,9 +713,9 @@ incoming_suggest (struct Operation *incoming,
   incoming->suggest_id = suggest_id++;
   if (0 == suggest_id)
     suggest_id++;
-  GNUNET_assert (GNUNET_SCHEDULER_NO_TASK != incoming->timeout_task);
+  GNUNET_assert (NULL != incoming->timeout_task);
   GNUNET_SCHEDULER_cancel (incoming->timeout_task);
-  incoming->timeout_task = GNUNET_SCHEDULER_NO_TASK;
+  incoming->timeout_task = NULL;
   mqm = GNUNET_MQ_msg_nested_mh (cmsg,
                                  GNUNET_MESSAGE_TYPE_SET_REQUEST,
                                  incoming->spec->context_msg);
@@ -552,7 +725,8 @@ incoming_suggest (struct Operation *incoming,
               incoming->suggest_id);
   cmsg->accept_id = htonl (incoming->suggest_id);
   cmsg->peer_id = incoming->spec->peer;
-  GNUNET_MQ_send (listener->client_mq, mqm);
+  GNUNET_MQ_send (listener->client_mq,
+                  mqm);
 }
 
 
@@ -578,7 +752,7 @@ handle_incoming_msg (struct Operation *op,
                      const struct GNUNET_MessageHeader *mh)
 {
   const struct OperationRequestMessage *msg;
-  struct Listener *listener;
+  struct Listener *listener = op->listener;
   struct OperationSpecification *spec;
   const struct GNUNET_MessageHeader *nested_context;
 
@@ -607,36 +781,168 @@ handle_incoming_msg (struct Operation *op,
   /* Make a copy of the nested_context (application-specific context
      information that is opaque to set) so we can pass it to the
      listener later on */
-  if (NULL != spec->context_msg)
+  if (NULL != nested_context)
     spec->context_msg = GNUNET_copy_message (nested_context);
   spec->operation = ntohl (msg->operation);
-  spec->app_id = msg->app_id;
+  spec->app_id = listener->app_id;
   spec->salt = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE,
                                          UINT32_MAX);
   spec->peer = op->peer;
   spec->remote_element_count = ntohl (msg->element_count);
   op->spec = spec;
 
-  listener = listener_get_by_target (ntohl (msg->operation),
-                                     &msg->app_id);
-  if (NULL == listener)
+  listener = op->listener;
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Received P2P operation request (op %u, port %s) for active listener\n",
+              (uint32_t) ntohl (msg->operation),
+              GNUNET_h2s (&listener->app_id));
+  incoming_suggest (op,
+                    listener);
+  return GNUNET_OK;
+}
+
+
+static void
+execute_add (struct Set *set,
+             const struct GNUNET_MessageHeader *m)
+{
+  const struct GNUNET_SET_ElementMessage *msg;
+  struct GNUNET_SET_Element el;
+  struct ElementEntry *ee;
+  struct GNUNET_HashCode hash;
+
+  GNUNET_assert (GNUNET_MESSAGE_TYPE_SET_ADD == ntohs (m->type));
+
+  msg = (const struct GNUNET_SET_ElementMessage *) m;
+  el.size = ntohs (m->size) - sizeof *msg;
+  el.data = &msg[1];
+  el.element_type = ntohs (msg->element_type);
+  GNUNET_SET_element_hash (&el, &hash);
+
+  ee = GNUNET_CONTAINER_multihashmap_get (set->content->elements,
+                                          &hash);
+
+  if (NULL == ee)
   {
-    GNUNET_break (GNUNET_SCHEDULER_NO_TASK != op->timeout_task);
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-                "No matching listener for incoming request (op %u, app %s), waiting with timeout\n",
-                ntohl (msg->operation),
-                GNUNET_h2s (&msg->app_id));
-    return GNUNET_OK;
+                "Client inserts element %s of size %u\n",
+                GNUNET_h2s (&hash),
+                el.size);
+    ee = GNUNET_malloc (el.size + sizeof *ee);
+    ee->element.size = el.size;
+    GNUNET_memcpy (&ee[1],
+            el.data,
+            el.size);
+    ee->element.data = &ee[1];
+    ee->element.element_type = el.element_type;
+    ee->remote = GNUNET_NO;
+    ee->mutations = NULL;
+    ee->mutations_size = 0;
+    ee->element_hash = hash;
+    GNUNET_break (GNUNET_YES ==
+                  GNUNET_CONTAINER_multihashmap_put (set->content->elements,
+                                                     &ee->element_hash,
+                                                     ee,
+                                                     GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
+  }
+  else if (GNUNET_YES == _GSS_is_element_of_set (ee, set))
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Client inserted element %s of size %u twice (ignored)\n",
+                GNUNET_h2s (&hash),
+                el.size);
+
+    /* same element inserted twice */
+    return;
+  }
+
+  {
+    struct MutationEvent mut = {
+      .generation = set->current_generation,
+      .added = GNUNET_YES
+    };
+    GNUNET_array_append (ee->mutations,
+                         ee->mutations_size,
+                         mut);
+  }
+
+  set->vt->add (set->state, ee);
+}
+
+
+static void
+execute_remove (struct Set *set,
+                const struct GNUNET_MessageHeader *m)
+{
+  const struct GNUNET_SET_ElementMessage *msg;
+  struct GNUNET_SET_Element el;
+  struct ElementEntry *ee;
+  struct GNUNET_HashCode hash;
+
+  GNUNET_assert (GNUNET_MESSAGE_TYPE_SET_REMOVE == ntohs (m->type));
+
+  msg = (const struct GNUNET_SET_ElementMessage *) m;
+  el.size = ntohs (m->size) - sizeof *msg;
+  el.data = &msg[1];
+  el.element_type = ntohs (msg->element_type);
+  GNUNET_SET_element_hash (&el, &hash);
+  ee = GNUNET_CONTAINER_multihashmap_get (set->content->elements,
+                                          &hash);
+  if (NULL == ee)
+  {
+    /* Client tried to remove non-existing element. */
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Client removes non-existing element of size %u\n",
+                el.size);
+    return;
+  }
+  if (GNUNET_NO == _GSS_is_element_of_set (ee, set))
+  {
+    /* Client tried to remove element twice */
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Client removed element of size %u twice (ignored)\n",
+                el.size);
+    return;
+  }
+  else
+  {
+    struct MutationEvent mut = {
+      .generation = set->current_generation,
+      .added = GNUNET_NO
+    };
+
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Client removes element of size %u\n",
+                el.size);
+
+    GNUNET_array_append (ee->mutations,
+                         ee->mutations_size,
+                         mut);
+  }
+  set->vt->remove (set->state, ee);
+}
+
+
+
+static void
+execute_mutation (struct Set *set,
+                  const struct GNUNET_MessageHeader *m)
+{
+  switch (ntohs (m->type))
+  {
+    case GNUNET_MESSAGE_TYPE_SET_ADD:
+      execute_add (set, m);
+      break;
+    case GNUNET_MESSAGE_TYPE_SET_REMOVE:
+      execute_remove (set, m);
+      break;
+    default:
+      GNUNET_break (0);
   }
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              "Received P2P operation request (op %u, app %s) for active listener\n",
-              ntohl (msg->operation),
-              GNUNET_h2s (&msg->app_id));
-  incoming_suggest (op, listener);
-  return GNUNET_OK;
 }
 
 
+
 /**
  * Send the next element of a set to the set's client.  The next element is given by
  * the set's current hashmap iterator.  The set's iterator will be set to NULL if there
@@ -659,25 +965,63 @@ send_client_element (struct Set *set)
   struct GNUNET_SET_IterResponseMessage *msg;
 
   GNUNET_assert (NULL != set->iter);
+
+again:
+
   ret = GNUNET_CONTAINER_multihashmap_iterator_next (set->iter,
                                                      NULL,
                                                      (const void **) &ee);
   if (GNUNET_NO == ret)
   {
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Iteration on %p done.\n",
+                (void *) set);
     ev = GNUNET_MQ_msg_header (GNUNET_MESSAGE_TYPE_SET_ITER_DONE);
     GNUNET_CONTAINER_multihashmap_iterator_destroy (set->iter);
     set->iter = NULL;
+    set->iteration_id++;
+
+    GNUNET_assert (set->content->iterator_count > 0);
+    set->content->iterator_count -= 1;
+
+    if (0 == set->content->iterator_count)
+    {
+      while (NULL != set->content->pending_mutations_head)
+      {
+        struct PendingMutation *pm;
+
+        pm = set->content->pending_mutations_head;
+        GNUNET_CONTAINER_DLL_remove (set->content->pending_mutations_head,
+                                     set->content->pending_mutations_tail,
+                                     pm);
+        GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                    "Executing pending mutation on %p.\n",
+                    (void *) pm->set);
+        execute_mutation (pm->set, pm->mutation_message);
+        GNUNET_free (pm->mutation_message);
+        GNUNET_free (pm);
+      }
+    }
+
   }
   else
   {
     GNUNET_assert (NULL != ee);
+
+    if (GNUNET_NO == is_element_of_iteration (ee, set))
+      goto again;
+
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Sending iteration element on %p.\n",
+                (void *) set);
     ev = GNUNET_MQ_msg_extra (msg,
                               ee->element.size,
                               GNUNET_MESSAGE_TYPE_SET_ITER_ELEMENT);
-    memcpy (&msg[1],
+    GNUNET_memcpy (&msg[1],
             ee->element.data,
             ee->element.size);
-    msg->element_type = ee->element.element_type;
+    msg->element_type = htons (ee->element.element_type);
+    msg->iteration_id = htons (set->iteration_id);
   }
   GNUNET_MQ_send (set->client_mq, ev);
 }
@@ -689,15 +1033,14 @@ send_client_element (struct Set *set)
  * can right now start an iteration. If all checks out, starts
  * sending the elements of the set to the client.
  *
- * @param cls unused
- * @param client client that sent the message
+ * @param cls client that sent the message
  * @param m message sent by the client
  */
 static void
 handle_client_iterate (void *cls,
-                       struct GNUNET_SERVER_Client *client,
                        const struct GNUNET_MessageHeader *m)
 {
+  struct GNUNET_SERVICE_Client *client = cls;
   struct Set *set;
 
   set = set_get (client);
@@ -705,22 +1048,25 @@ handle_client_iterate (void *cls,
   {
     /* attempt to iterate over a non existing set */
     GNUNET_break (0);
-    GNUNET_SERVER_client_disconnect (client);
+    GNUNET_SERVICE_client_drop (client);
     return;
   }
   if (NULL != set->iter)
   {
     /* Only one concurrent iterate-action allowed per set */
     GNUNET_break (0);
-    GNUNET_SERVER_client_disconnect (client);
+    GNUNET_SERVICE_client_drop (client);
     return;
   }
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              "Iterating union set with %u elements\n",
-              GNUNET_CONTAINER_multihashmap_size (set->elements));
-  GNUNET_SERVER_receive_done (client,
-                              GNUNET_OK);
-  set->iter = GNUNET_CONTAINER_multihashmap_iterator_create (set->elements);
+              "Iterating set %p in gen %u with %u content elements\n",
+              (void *) set,
+              set->current_generation,
+              GNUNET_CONTAINER_multihashmap_size (set->content->elements));
+  GNUNET_SERVICE_client_continue (client);
+  set->content->iterator_count += 1;
+  set->iter = GNUNET_CONTAINER_multihashmap_iterator_create (set->content->elements);
+  set->iter_generation = set->current_generation;
   send_client_element (set);
 }
 
@@ -730,27 +1076,24 @@ handle_client_iterate (void *cls,
  * the first request from a client, and includes the type of set
  * operation to be performed.
  *
- * @param cls unused
- * @param client client that sent the message
+ * @param cls client that sent the message
  * @param m message sent by the client
  */
 static void
 handle_client_create_set (void *cls,
-                          struct GNUNET_SERVER_Client *client,
-                          const struct GNUNET_MessageHeader *m)
+                          const struct GNUNET_SET_CreateMessage *msg)
 {
-  const struct GNUNET_SET_CreateMessage *msg;
+  struct GNUNET_SERVICE_Client *client = cls;
   struct Set *set;
 
-  msg = (const struct GNUNET_SET_CreateMessage *) m;
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
               "Client created new set (operation %u)\n",
-              ntohs (msg->operation));
+              (uint32_t) ntohl (msg->operation));
   if (NULL != set_get (client))
   {
     /* There can only be one set per client */
     GNUNET_break (0);
-    GNUNET_SERVER_client_disconnect (client);
+    GNUNET_SERVICE_client_drop (client);
     return;
   }
   set = GNUNET_new (struct Set);
@@ -765,60 +1108,345 @@ handle_client_create_set (void *cls,
   default:
     GNUNET_free (set);
     GNUNET_break (0);
-    GNUNET_SERVER_client_disconnect (client);
+    GNUNET_SERVICE_client_drop (client);
     return;
   }
+  set->operation = ntohl (msg->operation);
   set->state = set->vt->create ();
-  set->elements = GNUNET_CONTAINER_multihashmap_create (1, GNUNET_YES);
+  if (NULL == set->state)
+  {
+    /* initialization failed (i.e. out of memory) */
+    GNUNET_free (set);
+    GNUNET_SERVICE_client_drop (client);
+    return;
+  }
+  set->content = GNUNET_new (struct SetContent);
+  set->content->refcount = 1;
+  set->content->elements = GNUNET_CONTAINER_multihashmap_create (1, GNUNET_YES);
   set->client = client;
-  set->client_mq = GNUNET_MQ_queue_for_server_client (client);
+  set->client_mq = GNUNET_SERVICE_client_get_mq (client);
   GNUNET_CONTAINER_DLL_insert (sets_head,
                                sets_tail,
                                set);
-  GNUNET_SERVER_receive_done (client,
-                              GNUNET_OK);
+  GNUNET_SERVICE_client_continue (client);
 }
 
 
 /**
- * Called when a client wants to create a new listener.
+ * Timeout happens iff:
+ *  - we suggested an operation to our listener,
+ *    but did not receive a response in time
+ *  - we got the channel from a peer but no #GNUNET_MESSAGE_TYPE_SET_P2P_OPERATION_REQUEST
  *
- * @param cls unused
- * @param client client that sent the message
- * @param m message sent by the client
+ * @param cls channel context
+ * @param tc context information (why was this task triggered now)
  */
 static void
-handle_client_listen (void *cls,
-                      struct GNUNET_SERVER_Client *client,
-                      const struct GNUNET_MessageHeader *m)
+incoming_timeout_cb (void *cls)
 {
-  const struct GNUNET_SET_ListenMessage *msg;
-  struct Listener *listener;
-  struct Operation *op;
+  struct Operation *incoming = cls;
+
+  incoming->timeout_task = NULL;
+  GNUNET_assert (GNUNET_YES == incoming->is_incoming);
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Remote peer's incoming request timed out\n");
+  incoming_destroy (incoming);
+}
+
+
+/**
+ * Terminates an incoming operation in case we have not yet received an
+ * operation request. Called by the channel destruction handler.
+ *
+ * @param op the channel context
+ */
+static void
+handle_incoming_disconnect (struct Operation *op)
+{
+  GNUNET_assert (GNUNET_YES == op->is_incoming);
+  /* channel is already dead, incoming_destroy must not
+   * destroy it ... */
+  op->channel = NULL;
+  incoming_destroy (op);
+  op->vt = NULL;
+}
+
+
+/**
+ * Method called whenever another peer has added us to a channel the
+ * other peer initiated.  Only called (once) upon reception of data
+ * from a channel we listen on.
+ *
+ * The channel context represents the operation itself and gets added
+ * to a DLL, from where it gets looked up when our local listener
+ * client responds to a proposed/suggested operation or connects and
+ * associates with this operation.
+ *
+ * @param cls closure
+ * @param channel new handle to the channel
+ * @param source peer that started the channel
+ * @return initial channel context for the channel
+ *         returns NULL on error
+ */
+static void *
+channel_new_cb (void *cls,
+                struct GNUNET_CADET_Channel *channel,
+                const struct GNUNET_PeerIdentity *source)
+{
+  static const struct SetVT incoming_vt = {
+    .msg_handler = &handle_incoming_msg,
+    .peer_disconnect = &handle_incoming_disconnect
+  };
+  struct Listener *listener = cls;
+  struct Operation *incoming;
+
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "New incoming channel\n");
+  incoming = GNUNET_new (struct Operation);
+  incoming->listener = listener;
+  incoming->is_incoming = GNUNET_YES;
+  incoming->peer = *source;
+  incoming->channel = channel;
+  incoming->mq = GNUNET_CADET_get_mq (incoming->channel);
+  incoming->vt = &incoming_vt;
+  incoming->timeout_task
+    = GNUNET_SCHEDULER_add_delayed (INCOMING_CHANNEL_TIMEOUT,
+                                    &incoming_timeout_cb,
+                                    incoming);
+  GNUNET_CONTAINER_DLL_insert_tail (incoming_head,
+                                    incoming_tail,
+                                    incoming);
+  // incoming_suggest (incoming,
+  //                  listener);
+  return incoming;
+}
+
+
+/**
+ * Function called whenever a channel is destroyed.  Should clean up
+ * any associated state.  It must NOT call
+ * GNUNET_CADET_channel_destroy() on the channel.
+ *
+ * The peer_disconnect function is part of a a virtual table set initially either
+ * when a peer creates a new channel with us, or once we create
+ * a new channel ourselves (evaluate).
+ *
+ * Once we know the exact type of operation (union/intersection), the vt is
+ * replaced with an operation specific instance (_GSS_[op]_vt).
+ *
+ * @param channel_ctx place where local state associated
+ *                   with the channel is stored
+ * @param channel connection to the other end (henceforth invalid)
+ */
+static void
+channel_end_cb (void *channel_ctx,
+                const struct GNUNET_CADET_Channel *channel)
+{
+  struct Operation *op = channel_ctx;
+
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "channel_end_cb called\n");
+  op->channel = NULL;
+  op->keep++;
+  /* the vt can be null if a client already requested canceling op. */
+  if (NULL != op->vt)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "calling peer disconnect due to channel end\n");
+    op->vt->peer_disconnect (op);
+  }
+  op->keep--;
+  if (0 == op->keep)
+  {
+    /* cadet will never call us with the context again! */
+    GNUNET_free (op);
+  }
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "channel_end_cb finished\n");
+}
+
+
+/**
+ * Function called whenever an MQ-channel's transmission window size changes.
+ *
+ * The first callback in an outgoing channel will be with a non-zero value
+ * and will mean the channel is connected to the destination.
+ *
+ * For an incoming channel it will be called immediately after the
+ * #GNUNET_CADET_ConnectEventHandler, also with a non-zero value.
+ *
+ * @param cls Channel closure.
+ * @param channel Connection to the other end (henceforth invalid).
+ * @param window_size New window size. If the is more messages than buffer size
+ *                    this value will be negative..
+ */
+static void
+channel_window_cb (void *cls,
+                   const struct GNUNET_CADET_Channel *channel,
+                   int window_size)
+{
+  /* FIXME: not implemented, we could do flow control here... */
+}
+
+/**
+ * FIXME: hack-job. Migrate to proper handler array use!
+ *
+ * @param cls local state associated with the channel.
+ * @param message The actual message.
+ */
+static int
+check_p2p_message (void *cls,
+                   const struct GNUNET_MessageHeader *message)
+{
+  return GNUNET_OK;
+}
+
+
+/**
+ * FIXME: hack-job. Migrate to proper handler array use!
+ *
+ * Functions with this signature are called whenever a message is
+ * received via a cadet channel.
+ *
+ * The msg_handler is a virtual table set in initially either when a peer
+ * creates a new channel with us, or once we create a new channel
+ * ourselves (evaluate).
+ *
+ * Once we know the exact type of operation (union/intersection), the vt is
+ * replaced with an operation specific instance (_GSS_[op]_vt).
+ *
+ * @param cls local state associated with the channel.
+ * @param message The actual message.
+ */
+static void
+handle_p2p_message (void *cls,
+                    const struct GNUNET_MessageHeader *message)
+{
+  struct Operation *op = cls;
+  int ret;
+
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Dispatching cadet message (type: %u)\n",
+              ntohs (message->type));
+  /* do this before the handler, as the handler might kill the channel */
+  GNUNET_CADET_receive_done (op->channel);
+  if (NULL != op->vt)
+    ret = op->vt->msg_handler (op,
+                               message);
+  else
+    ret = GNUNET_SYSERR;
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Handled cadet message (type: %u)\n",
+              ntohs (message->type));
+  if (GNUNET_OK != ret)
+    GNUNET_CADET_channel_destroy (op->channel);
+}
+
+
+/**
+ * Called when a client wants to create a new listener.
+ *
+ * @param cls client that sent the message
+ * @param msg message sent by the client
+ */
+static void
+handle_client_listen (void *cls,
+                      const struct GNUNET_SET_ListenMessage *msg)
+{
+  struct GNUNET_SERVICE_Client *client = cls;
+  struct GNUNET_MQ_MessageHandler cadet_handlers[] = {
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_P2P_OPERATION_REQUEST,
+                           struct GNUNET_MessageHeader,
+                           NULL),
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_UNION_P2P_IBF,
+                           struct GNUNET_MessageHeader,
+                           NULL),
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_P2P_ELEMENTS,
+                           struct GNUNET_MessageHeader,
+                           NULL),
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_UNION_P2P_OFFER,
+                           struct GNUNET_MessageHeader,
+                           NULL),
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_UNION_P2P_INQUIRY,
+                           struct GNUNET_MessageHeader,
+                           NULL),
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_UNION_P2P_DEMAND,
+                           struct GNUNET_MessageHeader,
+                           NULL),
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_UNION_P2P_DONE,
+                           struct GNUNET_MessageHeader,
+                           NULL),
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_UNION_P2P_FULL_DONE,
+                           struct GNUNET_MessageHeader,
+                           NULL),
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_UNION_P2P_REQUEST_FULL,
+                           struct GNUNET_MessageHeader,
+                           NULL),
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_UNION_P2P_SE,
+                           struct GNUNET_MessageHeader,
+                           NULL),
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_UNION_P2P_SEC,
+                           struct GNUNET_MessageHeader,
+                           NULL),
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_UNION_P2P_FULL_ELEMENT,
+                           struct GNUNET_MessageHeader,
+                           NULL),
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_INTERSECTION_P2P_ELEMENT_INFO,
+                           struct GNUNET_MessageHeader,
+                           NULL),
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_INTERSECTION_P2P_BF,
+                           struct GNUNET_MessageHeader,
+                           NULL),
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_INTERSECTION_P2P_DONE,
+                           struct GNUNET_MessageHeader,
+                           NULL),
+    GNUNET_MQ_handler_end ()
+  };
+  struct Listener *listener;
 
-  msg = (const struct GNUNET_SET_ListenMessage *) m;
   if (NULL != listener_get (client))
   {
     /* max. one active listener per client! */
     GNUNET_break (0);
-    GNUNET_SERVER_client_disconnect (client);
+    GNUNET_SERVICE_client_drop (client);
     return;
   }
   listener = GNUNET_new (struct Listener);
   listener->client = client;
-  listener->client_mq = GNUNET_MQ_queue_for_server_client (client);
+  listener->client_mq = GNUNET_SERVICE_client_get_mq (client);
   listener->app_id = msg->app_id;
   listener->operation = ntohl (msg->operation);
   GNUNET_CONTAINER_DLL_insert_tail (listeners_head,
                                     listeners_tail,
                                     listener);
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              "New listener created (op %u, app %s)\n",
+              "New listener created (op %u, port %s)\n",
               listener->operation,
               GNUNET_h2s (&listener->app_id));
-
+  listener->open_port = GNUNET_CADET_open_porT (cadet,
+                                                &msg->app_id,
+                                                &channel_new_cb,
+                                                listener,
+                                                &channel_window_cb,
+                                                &channel_end_cb,
+                                                cadet_handlers);
   /* check for existing incoming requests the listener might be interested in */
-  for (op = incoming_head; NULL != op; op = op->next)
+  for (struct Operation *op = incoming_head; NULL != op; op = op->next)
   {
     if (NULL == op->spec)
       continue; /* no details available yet */
@@ -834,7 +1462,7 @@ handle_client_listen (void *cls,
     incoming_suggest (op,
                       listener);
   }
-  GNUNET_SERVER_receive_done (client, GNUNET_OK);
+  GNUNET_SERVICE_client_continue (client);
 }
 
 
@@ -842,26 +1470,22 @@ handle_client_listen (void *cls,
  * Called when the listening client rejects an operation
  * request by another peer.
  *
- * @param cls unused
- * @param client client that sent the message
- * @param m message sent by the client
+ * @param cls client that sent the message
+ * @param msg message sent by the client
  */
 static void
 handle_client_reject (void *cls,
-                      struct GNUNET_SERVER_Client *client,
-                      const struct GNUNET_MessageHeader *m)
+                      const struct GNUNET_SET_RejectMessage *msg)
 {
+  struct GNUNET_SERVICE_Client *client = cls;
   struct Operation *incoming;
-  const struct GNUNET_SET_RejectMessage *msg;
 
-  msg = (const struct GNUNET_SET_RejectMessage *) m;
   incoming = get_incoming (ntohl (msg->accept_reject_id));
   if (NULL == incoming)
   {
     /* no matching incoming operation for this reject */
     GNUNET_break (0);
-    GNUNET_SERVER_receive_done (client,
-                                GNUNET_SYSERR);
+    GNUNET_SERVICE_client_drop (client);
     return;
   }
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
@@ -869,129 +1493,97 @@ handle_client_reject (void *cls,
               incoming->spec->operation,
               GNUNET_h2s (&incoming->spec->app_id));
   GNUNET_CADET_channel_destroy (incoming->channel);
-  GNUNET_SERVER_receive_done (client,
-                              GNUNET_OK);
+  GNUNET_SERVICE_client_continue (client);
 }
 
 
 /**
- * Called when a client wants to add an element to a set it inhabits.
+ * Called when a client wants to add or remove an element to a set it inhabits.
  *
- * @param cls unused
- * @param client client that sent the message
+ * @param cls client that sent the message
+ * @param m message sent by the client
+ */
+static int
+check_client_mutation (void *cls,
+                       const struct GNUNET_MessageHeader *m)
+{
+  /* FIXME: any check we might want to do here? */
+  return GNUNET_OK;
+}
+
+
+/**
+ * Called when a client wants to add or remove an element to a set it inhabits.
+ *
+ * @param cls client that sent the message
  * @param m message sent by the client
  */
 static void
-handle_client_add (void *cls,
-                   struct GNUNET_SERVER_Client *client,
-                   const struct GNUNET_MessageHeader *m)
+handle_client_mutation (void *cls,
+                        const struct GNUNET_MessageHeader *m)
 {
+  struct GNUNET_SERVICE_Client *client = cls;
   struct Set *set;
-  const struct GNUNET_SET_ElementMessage *msg;
-  struct GNUNET_SET_Element el;
-  struct ElementEntry *ee;
-  struct ElementEntry *ee_dup;
 
   set = set_get (client);
   if (NULL == set)
   {
     /* client without a set requested an operation */
     GNUNET_break (0);
-    GNUNET_SERVER_client_disconnect (client);
+    GNUNET_SERVICE_client_drop (client);
     return;
   }
-  GNUNET_SERVER_receive_done (client,
-                              GNUNET_OK);
-  msg = (const struct GNUNET_SET_ElementMessage *) m;
-  el.size = ntohs (m->size) - sizeof *msg;
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-             "Client inserts element of size %u\n",
-              el.size);
-  el.data = &msg[1];
-  ee = GNUNET_malloc (el.size + sizeof *ee);
-  ee->element.size = el.size;
-  memcpy (&ee[1],
-          el.data,
-          el.size);
-  ee->element.data = &ee[1];
-  ee->generation_added = set->current_generation;
-  ee->remote = GNUNET_NO;
-  GNUNET_CRYPTO_hash (ee->element.data,
-                      el.size,
-                      &ee->element_hash);
-  ee_dup = GNUNET_CONTAINER_multihashmap_get (set->elements,
-                                              &ee->element_hash);
-  if (NULL != ee_dup)
+
+  GNUNET_SERVICE_client_continue (client);
+
+  if (0 != set->content->iterator_count)
   {
-    /* same element inserted twice */
-    GNUNET_break (0);
-    GNUNET_free (ee);
+    struct PendingMutation *pm;
+
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Scheduling mutation on set\n");
+
+    pm = GNUNET_new (struct PendingMutation);
+    pm->mutation_message = GNUNET_copy_message (m);
+    pm->set = set;
+    GNUNET_CONTAINER_DLL_insert_tail (set->content->pending_mutations_head,
+                                      set->content->pending_mutations_tail,
+                                      pm);
     return;
   }
-  GNUNET_break (GNUNET_YES ==
-                GNUNET_CONTAINER_multihashmap_put (set->elements,
-                                                   &ee->element_hash,
-                                                   ee,
-                                                   GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
-  set->vt->add (set->state, ee);
+  execute_mutation (set, m);
 }
 
 
 /**
- * Called when a client wants to remove an element from a set it
- * inhabits.
+ * Advance the current generation of a set,
+ * adding exclusion ranges if necessary.
  *
- * @param cls unused
- * @param client client that sent the message
- * @param m message sent by the client
+ * @param set the set where we want to advance the generation
  */
 static void
-handle_client_remove (void *cls,
-                      struct GNUNET_SERVER_Client *client,
-                      const struct GNUNET_MessageHeader *m)
+advance_generation (struct Set *set)
 {
-  struct Set *set;
-  const struct GNUNET_SET_ElementMessage *msg;
-  struct GNUNET_SET_Element el;
-  struct ElementEntry *ee;
-  struct GNUNET_HashCode hash;
+  struct GenerationRange r;
 
-  set = set_get (client);
-  if (NULL == set)
+  if (set->current_generation == set->content->latest_generation)
   {
-    /* client without a set requested an operation */
-    GNUNET_break (0);
-    GNUNET_SERVER_client_disconnect (client);
+    set->content->latest_generation += 1;
+    set->current_generation += 1;
     return;
   }
-  GNUNET_SERVER_receive_done (client,
-                              GNUNET_OK);
-  msg = (const struct GNUNET_SET_ElementMessage *) m;
-  el.size = ntohs (m->size) - sizeof *msg;
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-             "Client removes element of size %u\n",
-              el.size);
-  el.data = &msg[1];
-  GNUNET_CRYPTO_hash (el.data,
-                      el.size,
-                      &hash);
-  ee = GNUNET_CONTAINER_multihashmap_get (set->elements,
-                                          &hash);
-  if (NULL == ee)
-  {
-    /* Client tried to remove non-existing element */
-    GNUNET_break (0);
-    return;
-  }
-  if (GNUNET_YES == ee->removed)
-  {
-    /* Client tried to remove element twice */
-    GNUNET_break (0);
-    return;
-  }
-  ee->removed = GNUNET_YES;
-  ee->generation_removed = set->current_generation;
-  set->vt->remove (set->state, ee);
+
+  GNUNET_assert (set->current_generation < set->content->latest_generation);
+
+  r.start = set->current_generation + 1;
+  r.end = set->content->latest_generation + 1;
+
+  set->content->latest_generation = r.end;
+  set->current_generation = r.end;
+
+  GNUNET_array_append (set->excluded_generations,
+                       set->excluded_generations_size,
+                       r);
 }
 
 
@@ -1000,29 +1592,109 @@ handle_client_remove (void *cls,
  * peer.  Initiates the CADET connection to the listener and sends the
  * request.
  *
- * @param cls unused
- * @param client client that sent the message
- * @param m message sent by the client
+ * @param cls client that sent the message
+ * @param msg message sent by the client
+ * @return #GNUNET_OK if the message is well-formed
+ */
+static int
+check_client_evaluate (void *cls,
+                        const struct GNUNET_SET_EvaluateMessage *msg)
+{
+  /* FIXME: suboptimal, even if the context below could be NULL,
+     there are malformed messages this does not check for... */
+  return GNUNET_OK;
+}
+
+
+/**
+ * Called when a client wants to initiate a set operation with another
+ * peer.  Initiates the CADET connection to the listener and sends the
+ * request.
+ *
+ * @param cls client that sent the message
+ * @param msg message sent by the client
  */
 static void
 handle_client_evaluate (void *cls,
-                        struct GNUNET_SERVER_Client *client,
-                        const struct GNUNET_MessageHeader *m)
+                        const struct GNUNET_SET_EvaluateMessage *msg)
 {
+  struct GNUNET_SERVICE_Client *client = cls;
+  struct Operation *op = GNUNET_new (struct Operation);
+  const struct GNUNET_MQ_MessageHandler cadet_handlers[] = {
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_P2P_OPERATION_REQUEST,
+                           struct GNUNET_MessageHeader,
+                           op),
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_UNION_P2P_IBF,
+                           struct GNUNET_MessageHeader,
+                           op),
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_P2P_ELEMENTS,
+                           struct GNUNET_MessageHeader,
+                           op),
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_UNION_P2P_OFFER,
+                           struct GNUNET_MessageHeader,
+                           op),
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_UNION_P2P_INQUIRY,
+                           struct GNUNET_MessageHeader,
+                           op),
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_UNION_P2P_DEMAND,
+                           struct GNUNET_MessageHeader,
+                           op),
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_UNION_P2P_DONE,
+                           struct GNUNET_MessageHeader,
+                           op),
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_UNION_P2P_SE,
+                           struct GNUNET_MessageHeader,
+                           op),
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_UNION_P2P_SEC,
+                           struct GNUNET_MessageHeader,
+                           op),
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_UNION_P2P_FULL_DONE,
+                           struct GNUNET_MessageHeader,
+                           op),
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_UNION_P2P_REQUEST_FULL,
+                           struct GNUNET_MessageHeader,
+                           op),
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_UNION_P2P_FULL_ELEMENT,
+                           struct GNUNET_MessageHeader,
+                           op),
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_INTERSECTION_P2P_ELEMENT_INFO,
+                           struct GNUNET_MessageHeader,
+                           op),
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_INTERSECTION_P2P_BF,
+                           struct GNUNET_MessageHeader,
+                           op),
+    GNUNET_MQ_hd_var_size (p2p_message,
+                           GNUNET_MESSAGE_TYPE_SET_INTERSECTION_P2P_DONE,
+                           struct GNUNET_MessageHeader,
+                           op),
+    GNUNET_MQ_handler_end ()
+  };
   struct Set *set;
-  const struct GNUNET_SET_EvaluateMessage *msg;
   struct OperationSpecification *spec;
-  struct Operation *op;
   const struct GNUNET_MessageHeader *context;
 
   set = set_get (client);
   if (NULL == set)
   {
     GNUNET_break (0);
-    GNUNET_SERVER_client_disconnect (client);
+    GNUNET_free (op);
+    GNUNET_SERVICE_client_drop (client);
     return;
   }
-  msg = (const struct GNUNET_SET_EvaluateMessage *) m;
   spec = GNUNET_new (struct OperationSpecification);
   spec->operation = set->operation;
   spec->app_id = msg->app_id;
@@ -1030,26 +1702,39 @@ handle_client_evaluate (void *cls,
                                          UINT32_MAX);
   spec->peer = msg->target_peer;
   spec->set = set;
-  spec->result_mode = ntohs (msg->result_mode);
+  spec->result_mode = ntohl (msg->result_mode);
   spec->client_request_id = ntohl (msg->request_id);
+  spec->byzantine = msg->byzantine;
+  spec->byzantine_lower_bound = msg->byzantine_lower_bound;
+  spec->force_full = msg->force_full;
+  spec->force_delta = msg->force_delta;
   context = GNUNET_MQ_extract_nested_mh (msg);
-  op = GNUNET_new (struct Operation);
   op->spec = spec;
-  op->generation_created = set->current_generation++;
+
+  // Advance generation values, so that
+  // mutations won't interfer with the running operation.
+  op->generation_created = set->current_generation;
+  advance_generation (set);
+
   op->vt = set->vt;
   GNUNET_CONTAINER_DLL_insert (set->ops_head,
                                set->ops_tail,
                                op);
-  op->channel = GNUNET_CADET_channel_create (cadet,
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Creating new CADET channel to port %s\n",
+              GNUNET_h2s (&msg->app_id));
+  op->channel = GNUNET_CADET_channel_creatE (cadet,
                                              op,
                                              &msg->target_peer,
-                                             GNUNET_APPLICATION_TYPE_SET,
-                                             GNUNET_CADET_OPTION_RELIABLE);
-  op->mq = GNUNET_CADET_mq_create (op->channel);
+                                             &msg->app_id,
+                                             GNUNET_CADET_OPTION_RELIABLE,
+                                             &channel_window_cb,
+                                             &channel_end_cb,
+                                             cadet_handlers);
+  op->mq = GNUNET_CADET_get_mq (op->channel);
   set->vt->evaluate (op,
                      context);
-  GNUNET_SERVER_receive_done (client,
-                              GNUNET_OK);
+  GNUNET_SERVICE_client_continue (client);
 }
 
 
@@ -1058,16 +1743,14 @@ handle_client_evaluate (void *cls,
  * that we only expect acks for set elements, not after the
  * #GNUNET_MESSAGE_TYPE_SET_ITER_DONE message.
  *
- * @param cls unused
- * @param client the client
- * @param m the message
+ * @param cls client the client
+ * @param ack the message
  */
 static void
 handle_client_iter_ack (void *cls,
-                        struct GNUNET_SERVER_Client *client,
-                        const struct GNUNET_MessageHeader *m)
+                        const struct GNUNET_SET_IterAckMessage *ack)
 {
-  const struct GNUNET_SET_IterAckMessage *ack;
+  struct GNUNET_SERVICE_Client *client = cls;
   struct Set *set;
 
   set = set_get (client);
@@ -1075,7 +1758,7 @@ handle_client_iter_ack (void *cls,
   {
     /* client without a set acknowledged receiving a value */
     GNUNET_break (0);
-    GNUNET_SERVER_client_disconnect (client);
+    GNUNET_SERVICE_client_drop (client);
     return;
   }
   if (NULL == set->iter)
@@ -1083,12 +1766,10 @@ handle_client_iter_ack (void *cls,
     /* client sent an ack, but we were not expecting one (as
        set iteration has finished) */
     GNUNET_break (0);
-    GNUNET_SERVER_client_disconnect (client);
+    GNUNET_SERVICE_client_drop (client);
     return;
   }
-  ack = (const struct GNUNET_SET_IterAckMessage *) m;
-  GNUNET_SERVER_receive_done (client,
-                              GNUNET_OK);
+  GNUNET_SERVICE_client_continue (client);
   if (ntohl (ack->send_more))
   {
     send_client_element (set);
@@ -1097,25 +1778,172 @@ handle_client_iter_ack (void *cls,
   {
     GNUNET_CONTAINER_multihashmap_iterator_destroy (set->iter);
     set->iter = NULL;
+    set->iteration_id++;
   }
 }
 
 
 /**
- * Handle a request from the client to
- * cancel a running set operation.
+ * Handle a request from the client to copy a set.
  *
- * @param cls unused
- * @param client the client
+ * @param cls the client
  * @param mh the message
  */
 static void
+handle_client_copy_lazy_prepare (void *cls,
+                                 const struct GNUNET_MessageHeader *mh)
+{
+  struct GNUNET_SERVICE_Client *client = cls;
+  struct Set *set;
+  struct LazyCopyRequest *cr;
+  struct GNUNET_MQ_Envelope *ev;
+  struct GNUNET_SET_CopyLazyResponseMessage *resp_msg;
+
+  set = set_get (client);
+  if (NULL == set)
+  {
+    /* client without a set requested an operation */
+    GNUNET_break (0);
+    GNUNET_SERVICE_client_drop (client);
+    return;
+  }
+
+  cr = GNUNET_new (struct LazyCopyRequest);
+
+  cr->cookie = lazy_copy_cookie;
+  lazy_copy_cookie += 1;
+  cr->source_set = set;
+
+  GNUNET_CONTAINER_DLL_insert (lazy_copy_head,
+                               lazy_copy_tail,
+                               cr);
+
+
+  ev = GNUNET_MQ_msg (resp_msg,
+                      GNUNET_MESSAGE_TYPE_SET_COPY_LAZY_RESPONSE);
+  resp_msg->cookie = cr->cookie;
+  GNUNET_MQ_send (set->client_mq, ev);
+
+
+  GNUNET_SERVICE_client_continue (client);
+
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Client requested lazy copy\n");
+}
+
+
+/**
+ * Handle a request from the client to connect to a copy of a set.
+ *
+ * @param cls the client
+ * @param msg the message
+ */
+static void
+handle_client_copy_lazy_connect (void *cls,
+                                 const struct GNUNET_SET_CopyLazyConnectMessage *msg)
+{
+  struct GNUNET_SERVICE_Client *client = cls;
+  struct LazyCopyRequest *cr;
+  struct Set *set;
+  int found;
+
+  if (NULL != set_get (client))
+  {
+    /* There can only be one set per client */
+    GNUNET_break (0);
+    GNUNET_SERVICE_client_drop (client);
+    return;
+  }
+
+  found = GNUNET_NO;
+
+  for (cr = lazy_copy_head; NULL != cr; cr = cr->next)
+  {
+    if (cr->cookie == msg->cookie)
+    {
+      found = GNUNET_YES;
+      break;
+    }
+  }
+
+  if (GNUNET_NO == found)
+  {
+    /* client asked for copy with cookie we don't know */
+    GNUNET_break (0);
+    GNUNET_SERVICE_client_drop (client);
+    return;
+  }
+
+  GNUNET_CONTAINER_DLL_remove (lazy_copy_head,
+                               lazy_copy_tail,
+                               cr);
+
+  set = GNUNET_new (struct Set);
+
+  switch (cr->source_set->operation)
+  {
+  case GNUNET_SET_OPERATION_INTERSECTION:
+    set->vt = _GSS_intersection_vt ();
+    break;
+  case GNUNET_SET_OPERATION_UNION:
+    set->vt = _GSS_union_vt ();
+    break;
+  default:
+    GNUNET_assert (0);
+    return;
+  }
+
+  if (NULL == set->vt->copy_state)
+  {
+    /* Lazy copy not supported for this set operation */
+    GNUNET_break (0);
+    GNUNET_free (set);
+    GNUNET_free (cr);
+    GNUNET_SERVICE_client_drop (client);
+    return;
+  }
+
+  set->operation = cr->source_set->operation;
+  set->state = set->vt->copy_state (cr->source_set);
+  set->content = cr->source_set->content;
+  set->content->refcount += 1;
+
+  set->current_generation = cr->source_set->current_generation;
+  set->excluded_generations_size = cr->source_set->excluded_generations_size;
+  set->excluded_generations = GNUNET_memdup (cr->source_set->excluded_generations,
+                                             set->excluded_generations_size * sizeof (struct GenerationRange));
+
+  /* Advance the generation of the new set, so that mutations to the
+     of the cloned set and the source set are independent. */
+  advance_generation (set);
+
+
+  set->client = client;
+  set->client_mq = GNUNET_SERVICE_client_get_mq (client);
+  GNUNET_CONTAINER_DLL_insert (sets_head,
+                               sets_tail,
+                               set);
+
+  GNUNET_free (cr);
+
+  GNUNET_SERVICE_client_continue (client);
+
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Client connected to lazy set\n");
+}
+
+
+/**
+ * Handle a request from the client to cancel a running set operation.
+ *
+ * @param cls the client
+ * @param msg the message
+ */
+static void
 handle_client_cancel (void *cls,
-                      struct GNUNET_SERVER_Client *client,
-                      const struct GNUNET_MessageHeader *mh)
+                      const struct GNUNET_SET_CancelMessage *msg)
 {
-  const struct GNUNET_SET_CancelMessage *msg =
-      (const struct GNUNET_SET_CancelMessage *) mh;
+  struct GNUNET_SERVICE_Client *client = cls;
   struct Set *set;
   struct Operation *op;
   int found;
@@ -1125,12 +1953,12 @@ handle_client_cancel (void *cls,
   {
     /* client without a set requested an operation */
     GNUNET_break (0);
-    GNUNET_SERVER_client_disconnect (client);
+    GNUNET_SERVICE_client_drop (client);
     return;
   }
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
               "Client requested cancel for op %u\n",
-              ntohl (msg->request_id));
+              (uint32_t) ntohl (msg->request_id));
   found = GNUNET_NO;
   for (op = set->ops_head; NULL != op; op = op->next)
   {
@@ -1155,8 +1983,7 @@ handle_client_cancel (void *cls,
     _GSS_operation_destroy (op,
                             GNUNET_YES);
   }
-  GNUNET_SERVER_receive_done (client,
-                              GNUNET_OK);
+  GNUNET_SERVICE_client_continue (client);
 }
 
 
@@ -1165,28 +1992,25 @@ handle_client_cancel (void *cls,
  * came from a remote peer.  We forward the accept to the associated
  * operation for handling
  *
- * @param cls unused
- * @param client the client
- * @param mh the message
+ * @param cls the client
+ * @param msg the message
  */
 static void
 handle_client_accept (void *cls,
-                      struct GNUNET_SERVER_Client *client,
-                      const struct GNUNET_MessageHeader *mh)
+                      const struct GNUNET_SET_AcceptMessage *msg)
 {
+  struct GNUNET_SERVICE_Client *client = cls;
   struct Set *set;
-  const struct GNUNET_SET_AcceptMessage *msg;
   struct Operation *op;
   struct GNUNET_SET_ResultMessage *result_message;
   struct GNUNET_MQ_Envelope *ev;
 
-  msg = (const struct GNUNET_SET_AcceptMessage *) mh;
   set = set_get (client);
   if (NULL == set)
   {
     /* client without a set requested to accept */
     GNUNET_break (0);
-    GNUNET_SERVER_client_disconnect (client);
+    GNUNET_SERVICE_client_drop (client);
     return;
   }
   op = get_incoming (ntohl (msg->accept_reject_id));
@@ -1202,13 +2026,13 @@ handle_client_accept (void *cls,
     result_message->element_type = 0;
     result_message->result_status = htons (GNUNET_SET_STATUS_FAILURE);
     GNUNET_MQ_send (set->client_mq, ev);
-    GNUNET_SERVER_receive_done (client, GNUNET_OK);
+    GNUNET_SERVICE_client_continue (client);
     return;
   }
 
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
               "Client accepting request %u\n",
-              ntohl (msg->accept_reject_id));
+              (uint32_t) ntohl (msg->accept_reject_id));
   GNUNET_assert (GNUNET_YES == op->is_incoming);
   op->is_incoming = GNUNET_NO;
   GNUNET_CONTAINER_DLL_remove (incoming_head,
@@ -1220,11 +2044,19 @@ handle_client_accept (void *cls,
                                op);
   op->spec->client_request_id = ntohl (msg->request_id);
   op->spec->result_mode = ntohl (msg->result_mode);
-  op->generation_created = set->current_generation++;
+  op->spec->byzantine = msg->byzantine;
+  op->spec->byzantine_lower_bound = msg->byzantine_lower_bound;
+  op->spec->force_full = msg->force_full;
+  op->spec->force_delta = msg->force_delta;
+
+  // Advance generation values, so that
+  // mutations won't interfer with the running operation.
+  op->generation_created = set->current_generation;
+  advance_generation (set);
+
   op->vt = set->vt;
   op->vt->accept (op);
-  GNUNET_SERVER_receive_done (client,
-                              GNUNET_OK);
+  GNUNET_SERVICE_client_continue (client);
 }
 
 
@@ -1232,11 +2064,9 @@ handle_client_accept (void *cls,
  * Called to clean up, after a shutdown has been requested.
  *
  * @param cls closure
- * @param tc context information (why was this task triggered now)
  */
 static void
-shutdown_task (void *cls,
-               const struct GNUNET_SCHEDULER_TaskContext *tc)
+shutdown_task (void *cls)
 {
   while (NULL != incoming_head)
     incoming_destroy (incoming_head);
@@ -1252,296 +2082,98 @@ shutdown_task (void *cls,
     GNUNET_CADET_disconnect (cadet);
     cadet = NULL;
   }
+  GNUNET_STATISTICS_destroy (_GSS_statistics, GNUNET_YES);
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
               "handled shutdown request\n");
 }
 
 
-/**
- * Timeout happens iff:
- *  - we suggested an operation to our listener,
- *    but did not receive a response in time
- *  - we got the channel from a peer but no #GNUNET_MESSAGE_TYPE_SET_P2P_OPERATION_REQUEST
- *  - shutdown (obviously)
- *
- * @param cls channel context
- * @param tc context information (why was this task triggered now)
- */
-static void
-incoming_timeout_cb (void *cls,
-                     const struct GNUNET_SCHEDULER_TaskContext *tc)
-{
-  struct Operation *incoming = cls;
-
-  incoming->timeout_task = GNUNET_SCHEDULER_NO_TASK;
-  GNUNET_assert (GNUNET_YES == incoming->is_incoming);
-  if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
-    return;
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              "Remote peer's incoming request timed out\n");
-  incoming_destroy (incoming);
-}
-
-
-/**
- * Terminates an incoming operation in case we have not yet received an
- * operation request. Called by the channel destruction handler.
- *
- * @param op the channel context
- */
-static void
-handle_incoming_disconnect (struct Operation *op)
-{
-  GNUNET_assert (GNUNET_YES == op->is_incoming);
-  /* channel is already dead, incoming_destroy must not
-   * destroy it ... */
-  op->channel = NULL;
-  incoming_destroy (op);
-  op->vt = NULL;
-}
-
-
-/**
- * Method called whenever another peer has added us to a channel the
- * other peer initiated.  Only called (once) upon reception of data
- * with a message type which was subscribed to in
- * GNUNET_CADET_connect().
- *
- * The channel context represents the operation itself and gets added to a DLL,
- * from where it gets looked up when our local listener client responds
- * to a proposed/suggested operation or connects and associates with this operation.
- *
- * @param cls closure
- * @param channel new handle to the channel
- * @param initiator peer that started the channel
- * @param port Port this channel is for.
- * @param options Unused.
- * @return initial channel context for the channel
- *         returns NULL on error
- */
-static void *
-channel_new_cb (void *cls,
-                struct GNUNET_CADET_Channel *channel,
-                const struct GNUNET_PeerIdentity *initiator,
-                uint32_t port,
-                enum GNUNET_CADET_ChannelOption options)
-{
-  static const struct SetVT incoming_vt = {
-    .msg_handler = &handle_incoming_msg,
-    .peer_disconnect = &handle_incoming_disconnect
-  };
-  struct Operation *incoming;
-
-  if (GNUNET_APPLICATION_TYPE_SET != port)
-  {
-    GNUNET_break (0);
-    GNUNET_CADET_channel_destroy (channel);
-    return NULL;
-  }
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              "New incoming channel\n");
-  incoming = GNUNET_new (struct Operation);
-  incoming->is_incoming = GNUNET_YES;
-  incoming->peer = *initiator;
-  incoming->channel = channel;
-  incoming->mq = GNUNET_CADET_mq_create (incoming->channel);
-  incoming->vt = &incoming_vt;
-  incoming->timeout_task
-    = GNUNET_SCHEDULER_add_delayed (INCOMING_CHANNEL_TIMEOUT,
-                                    &incoming_timeout_cb,
-                                    incoming);
-  GNUNET_CONTAINER_DLL_insert_tail (incoming_head,
-                                    incoming_tail,
-                                    incoming);
-  return incoming;
-}
-
-
-/**
- * Function called whenever a channel is destroyed.  Should clean up
- * any associated state.  It must NOT call
- * GNUNET_CADET_channel_destroy() on the channel.
- *
- * The peer_disconnect function is part of a a virtual table set initially either
- * when a peer creates a new channel with us (#channel_new_cb()), or once we create
- * a new channel ourselves (evaluate).
- *
- * Once we know the exact type of operation (union/intersection), the vt is
- * replaced with an operation specific instance (_GSS_[op]_vt).
- *
- * @param cls closure (set from GNUNET_CADET_connect())
- * @param channel connection to the other end (henceforth invalid)
- * @param channel_ctx place where local state associated
- *                   with the channel is stored
- */
-static void
-channel_end_cb (void *cls,
-                const struct GNUNET_CADET_Channel *channel,
-                void *channel_ctx)
-{
-  struct Operation *op = channel_ctx;
-
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              "channel_end_cb called\n");
-  op->channel = NULL;
-  /* the vt can be null if a client already requested canceling op. */
-  if (NULL != op->vt)
-  {
-    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-                "calling peer disconnect due to channel end\n");
-    op->vt->peer_disconnect (op);
-  }
-  if (GNUNET_YES != op->keep)
-  {
-    /* cadet will never call us with the context again! */
-    GNUNET_free (op);
-  }
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              "channel_end_cb finished\n");
-}
-
-
-/**
- * Functions with this signature are called whenever a message is
- * received via a cadet channel.
- *
- * The msg_handler is a virtual table set in initially either when a peer
- * creates a new channel with us (channel_new_cb), or once we create a new channel
- * ourselves (evaluate).
- *
- * Once we know the exact type of operation (union/intersection), the vt is
- * replaced with an operation specific instance (_GSS_[op]_vt).
- *
- * @param cls Closure (set from GNUNET_CADET_connect()).
- * @param channel Connection to the other end.
- * @param channel_ctx Place to store local state associated with the channel.
- * @param message The actual message.
- * @return #GNUNET_OK to keep the channel open,
- *         #GNUNET_SYSERR to close it (signal serious error).
- */
-static int
-dispatch_p2p_message (void *cls,
-                      struct GNUNET_CADET_Channel *channel,
-                      void **channel_ctx,
-                      const struct GNUNET_MessageHeader *message)
-{
-  struct Operation *op = *channel_ctx;
-  int ret;
-
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              "Dispatching cadet message (type: %u)\n",
-              ntohs (message->type));
-  /* do this before the handler, as the handler might kill the channel */
-  GNUNET_CADET_receive_done (channel);
-  if (NULL != op->vt)
-    ret = op->vt->msg_handler (op,
-                               message);
-  else
-    ret = GNUNET_SYSERR;
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              "Handled cadet message (type: %u)\n",
-              ntohs (message->type));
-  return ret;
-}
-
-
 /**
  * Function called by the service's run
  * method to run service-specific setup code.
  *
  * @param cls closure
- * @param server the initialized server
  * @param cfg configuration to use
+ * @param service the initialized service
  */
 static void
-run (void *cls, struct GNUNET_SERVER_Handle *server,
-     const struct GNUNET_CONFIGURATION_Handle *cfg)
+run (void *cls,
+     const struct GNUNET_CONFIGURATION_Handle *cfg,
+     struct GNUNET_SERVICE_Handle *service)
 {
-  static const struct GNUNET_SERVER_MessageHandler server_handlers[] = {
-    { &handle_client_accept, NULL,
-      GNUNET_MESSAGE_TYPE_SET_ACCEPT,
-      sizeof (struct GNUNET_SET_AcceptMessage)},
-    { &handle_client_iter_ack, NULL,
-      GNUNET_MESSAGE_TYPE_SET_ITER_ACK,
-      sizeof (struct GNUNET_SET_IterAckMessage) },
-    { &handle_client_add, NULL,
-      GNUNET_MESSAGE_TYPE_SET_ADD,
-      0},
-    { &handle_client_create_set, NULL,
-      GNUNET_MESSAGE_TYPE_SET_CREATE,
-      sizeof (struct GNUNET_SET_CreateMessage)},
-    { &handle_client_iterate, NULL,
-      GNUNET_MESSAGE_TYPE_SET_ITER_REQUEST,
-      sizeof (struct GNUNET_MessageHeader)},
-    { &handle_client_evaluate, NULL,
-      GNUNET_MESSAGE_TYPE_SET_EVALUATE,
-      0},
-    { &handle_client_listen, NULL,
-      GNUNET_MESSAGE_TYPE_SET_LISTEN,
-      sizeof (struct GNUNET_SET_ListenMessage)},
-    { &handle_client_reject, NULL,
-      GNUNET_MESSAGE_TYPE_SET_REJECT,
-      sizeof (struct GNUNET_SET_RejectMessage)},
-    { &handle_client_remove, NULL,
-      GNUNET_MESSAGE_TYPE_SET_REMOVE,
-      0},
-    { &handle_client_cancel, NULL,
-      GNUNET_MESSAGE_TYPE_SET_CANCEL,
-      sizeof (struct GNUNET_SET_CancelMessage)},
-    { NULL, NULL, 0, 0}
-  };
-  static const struct GNUNET_CADET_MessageHandler cadet_handlers[] = {
-    { &dispatch_p2p_message, GNUNET_MESSAGE_TYPE_SET_P2P_OPERATION_REQUEST, 0},
-    { &dispatch_p2p_message, GNUNET_MESSAGE_TYPE_SET_UNION_P2P_IBF, 0},
-    { &dispatch_p2p_message, GNUNET_MESSAGE_TYPE_SET_P2P_ELEMENTS, 0},
-    { &dispatch_p2p_message, GNUNET_MESSAGE_TYPE_SET_P2P_DONE, 0},
-    { &dispatch_p2p_message, GNUNET_MESSAGE_TYPE_SET_P2P_ELEMENT_REQUESTS, 0},
-    { &dispatch_p2p_message, GNUNET_MESSAGE_TYPE_SET_UNION_P2P_SE, 0},
-    { &dispatch_p2p_message, GNUNET_MESSAGE_TYPE_SET_INTERSECTION_P2P_ELEMENT_INFO, 0},
-    { &dispatch_p2p_message, GNUNET_MESSAGE_TYPE_SET_INTERSECTION_P2P_BF, 0},
-    { &dispatch_p2p_message, GNUNET_MESSAGE_TYPE_SET_INTERSECTION_P2P_BF_PART, 0},
-    {NULL, 0, 0}
-  };
-  static const uint32_t cadet_ports[] = {GNUNET_APPLICATION_TYPE_SET, 0};
-
   configuration = cfg;
-  GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL,
-                                &shutdown_task, NULL);
-  GNUNET_SERVER_disconnect_notify (server,
-                                   &handle_client_disconnect, NULL);
-  GNUNET_SERVER_add_handlers (server,
-                              server_handlers);
-  cadet = GNUNET_CADET_connect (cfg, NULL,
-                                &channel_new_cb,
-                                &channel_end_cb,
-                                cadet_handlers,
-                                cadet_ports);
+  GNUNET_SCHEDULER_add_shutdown (&shutdown_task,
+                                 NULL);
+  _GSS_statistics = GNUNET_STATISTICS_create ("set", cfg);
+  cadet = GNUNET_CADET_connecT (cfg);
   if (NULL == cadet)
   {
     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
-                _("Could not connect to cadet service\n"));
+                _("Could not connect to CADET service\n"));
     return;
   }
 }
 
 
 /**
- * The main function for the set service.
- *
- * @param argc number of arguments from the command line
- * @param argv command line arguments
- * @return 0 ok, 1 on error
+ * Define "main" method using service macro.
  */
-int
-main (int argc,
-      char *const *argv)
-{
-  int ret;
+GNUNET_SERVICE_MAIN
+("set",
+ GNUNET_SERVICE_OPTION_NONE,
+ &run,
+ &client_connect_cb,
+ &client_disconnect_cb,
+ NULL,
+ GNUNET_MQ_hd_fixed_size (client_accept,
+                          GNUNET_MESSAGE_TYPE_SET_ACCEPT,
+                          struct GNUNET_SET_AcceptMessage,
+                          NULL),
+ GNUNET_MQ_hd_fixed_size (client_iter_ack,
+                          GNUNET_MESSAGE_TYPE_SET_ITER_ACK,
+                          struct GNUNET_SET_IterAckMessage,
+                          NULL),
+ GNUNET_MQ_hd_var_size (client_mutation,
+                        GNUNET_MESSAGE_TYPE_SET_ADD,
+                        struct GNUNET_MessageHeader,
+                        NULL),
+ GNUNET_MQ_hd_fixed_size (client_create_set,
+                          GNUNET_MESSAGE_TYPE_SET_CREATE,
+                          struct GNUNET_SET_CreateMessage,
+                          NULL),
+ GNUNET_MQ_hd_fixed_size (client_iterate,
+                          GNUNET_MESSAGE_TYPE_SET_ITER_REQUEST,
+                          struct GNUNET_MessageHeader,
+                          NULL),
+ GNUNET_MQ_hd_var_size (client_evaluate,
+                        GNUNET_MESSAGE_TYPE_SET_EVALUATE,
+                        struct GNUNET_SET_EvaluateMessage,
+                        NULL),
+ GNUNET_MQ_hd_fixed_size (client_listen,
+                          GNUNET_MESSAGE_TYPE_SET_LISTEN,
+                          struct GNUNET_SET_ListenMessage,
+                          NULL),
+ GNUNET_MQ_hd_fixed_size (client_reject,
+                          GNUNET_MESSAGE_TYPE_SET_REJECT,
+                          struct GNUNET_SET_RejectMessage,
+                          NULL),
+ GNUNET_MQ_hd_var_size (client_mutation,
+                        GNUNET_MESSAGE_TYPE_SET_REMOVE,
+                        struct GNUNET_MessageHeader,
+                        NULL),
+ GNUNET_MQ_hd_fixed_size (client_cancel,
+                          GNUNET_MESSAGE_TYPE_SET_CANCEL,
+                          struct GNUNET_SET_CancelMessage,
+                          NULL),
+ GNUNET_MQ_hd_fixed_size (client_copy_lazy_prepare,
+                          GNUNET_MESSAGE_TYPE_SET_COPY_LAZY_PREPARE,
+                          struct GNUNET_MessageHeader,
+                          NULL),
+ GNUNET_MQ_hd_fixed_size (client_copy_lazy_connect,
+                          GNUNET_MESSAGE_TYPE_SET_COPY_LAZY_CONNECT,
+                          struct GNUNET_SET_CopyLazyConnectMessage,
+                          NULL),
+ GNUNET_MQ_handler_end ());
 
-  ret = GNUNET_SERVICE_run (argc, argv, "set",
-                            GNUNET_SERVICE_OPTION_NONE,
-                            &run, NULL);
-  return (GNUNET_OK == ret) ? 0 : 1;
-}
 
 /* end of gnunet-service-set.c */