excluded test cases for SP for now, while it does not fully work yet
[oweals/gnunet.git] / src / scalarproduct / gnunet-service-scalarproduct.c
index 1e92074e3b85fd1693c03634a17f5c9a97c9acad..3494703333e04d3ea46744dea3f7eee2261a534c 100644 (file)
  */
 enum SessionState
 {
+    CLIENT_REQUEST_RECEIVED,
     WAITING_FOR_BOBS_CONNECT,
-    MESSAGE_FROM_RESPONDING_CLIENT_RECEIVED,
-    WAITING_FOR_RESPONSE_FROM_SERVICE,
-    REQUEST_FROM_SERVICE_RECEIVED,
+    CLIENT_RESPONSE_RECEIVED,
+    WAITING_FOR_SERVICE_REQUEST,
+    WAITING_FOR_SERVICE_RESPONSE,
+    SERVICE_REQUEST_RECEIVED,
+    SERVICE_RESPONSE_RECEIVED,
     FINALIZED
 };
 
@@ -113,18 +116,18 @@ struct ServiceSession
     /**
      * how many elements we were supplied with from the client
      */
-    uint16_t element_count;
+    uint32_t element_count;
 
     /**
      * how many elements actually are used after applying the mask
      */
-    uint16_t used_element_count;
+    uint32_t used_element_count;
 
     /**
      * how many bytes the mask is long. 
      * just for convenience so we don't have to re-re-re calculate it each time
      */
-    uint16_t mask_length;
+    uint32_t mask_length;
 
     /**
      * all the vector elements we received
@@ -194,7 +197,7 @@ static unsigned char * my_pubkey_external;
 /**
  * Service's own public key represented as string
  */
-static uint16_t my_pubkey_external_length = 0;
+static uint32_t my_pubkey_external_length = 0;
 
 /**
  * Service's own n
@@ -456,7 +459,7 @@ decrypt_element (gcry_mpi_t m, gcry_mpi_t c, gcry_mpi_t mu, gcry_mpi_t lambda, g
  * @return an MPI value containing the calculated sum, never NULL
  */
 static gcry_mpi_t
-compute_square_sum (gcry_mpi_t * vector, uint16_t length)
+compute_square_sum (gcry_mpi_t * vector, uint32_t length)
 {
   gcry_mpi_t elem;
   gcry_mpi_t sum;
@@ -501,12 +504,14 @@ do_send_message (void *cls, size_t size, void *buf)
       written = size;
     }
 
-  if (GNUNET_MESSAGE_TYPE_SCALARPRODUCT_SERVICE_TO_CLIENT == ntohs(session->msg->type)){
-    session->state = FINALIZED;
-    session->client_transmit_handle = NULL;
+  switch (ntohs(session->msg->type)){
+    case GNUNET_MESSAGE_TYPE_SCALARPRODUCT_SERVICE_TO_CLIENT:
+      session->state = FINALIZED;
+      session->client_transmit_handle = NULL;
+      break;
+    default:
+      session->service_transmit_handle = NULL;
   }
-  else
-    session->service_transmit_handle = NULL;
     
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, 
              "Sent a message of type %hu.\n", 
@@ -525,7 +530,7 @@ do_send_message (void *cls, size_t size, void *buf)
  * @return the initialized vector, never NULL
  */
 static gcry_mpi_t *
-initialize_mpi_vector (uint16_t length)
+initialize_mpi_vector (uint32_t length)
 {
   uint32_t i;
   gcry_mpi_t * output = GNUNET_malloc (sizeof (gcry_mpi_t) * length);
@@ -572,7 +577,7 @@ permute_vector (gcry_mpi_t * vector,
  * @return an array of MPI values with random values
  */
 static gcry_mpi_t *
-generate_random_vector (uint16_t length)
+generate_random_vector (uint32_t length)
 {
   gcry_mpi_t * random_vector;
   int32_t value;
@@ -608,7 +613,7 @@ generate_random_vector (uint16_t length)
 static struct ServiceSession *
 find_matching_session (struct ServiceSession * tail,
                        const struct GNUNET_HashCode * key,
-                       uint16_t element_count,
+                       uint32_t element_count,
                        enum SessionState * state,
                        const struct GNUNET_PeerIdentity * peerid)
 {
@@ -676,7 +681,7 @@ handle_client_disconnect (void *cls,
                           struct GNUNET_SERVER_Client *client)
 {
   struct ServiceSession *session;
-
+  
   session = GNUNET_SERVER_client_get_user_context (client, struct ServiceSession);
   if (NULL == session)
     return;
@@ -689,7 +694,7 @@ handle_client_disconnect (void *cls,
       //we MUST terminate any client message underway
       if (session->service_transmit_handle && session->tunnel)
         GNUNET_MESH_notify_transmit_ready_cancel (session->service_transmit_handle);
-      if (session->tunnel && session->state == WAITING_FOR_RESPONSE_FROM_SERVICE)
+      if (session->tunnel && session->state == WAITING_FOR_SERVICE_RESPONSE)
         GNUNET_MESH_tunnel_destroy (session->tunnel);
     }
   if (GNUNET_SCHEDULER_NO_TASK != session->client_notification_task)
@@ -738,7 +743,7 @@ prepare_client_end_notification (void * cls,
   // 0 size and the first char in the product is 0, which should never be zero if encoding is used.
   msg->product_length = htonl (0);
   msg->range = 1;
-
+  
   session->msg = &msg->header;
 
   //transmit this message to our client
@@ -750,11 +755,11 @@ prepare_client_end_notification (void * cls,
                                                session);
 
   // if we could not even queue our request, something is wrong
-  if ( ! session->client_transmit_handle)
+  if ( NULL == session->client_transmit_handle)
     {
-      GNUNET_log (GNUNET_ERROR_TYPE_WARNING, _ ("Could not send message to client (%p)! This is OK if it was disconnected beforehand already.\n"), session->client);
+      GNUNET_log (GNUNET_ERROR_TYPE_WARNING, _ ("Could not send message to client (%p)!\n"), session->client);
       // usually gets freed by do_send_message
-      GNUNET_free (msg_obj);
+      session->msg = NULL;
       GNUNET_free (msg);
     }
   else
@@ -791,7 +796,7 @@ prepare_service_response (gcry_mpi_t * r,
                           struct ServiceSession * response)
 {
   struct GNUNET_SCALARPRODUCT_service_response * msg;
-  uint16_t msg_length = 0;
+  uint32_t msg_length = 0;
   unsigned char * current = NULL;
   unsigned char * element_exported = NULL;
   size_t element_length = 0;
@@ -805,8 +810,8 @@ prepare_service_response (gcry_mpi_t * r,
 
   msg->header.type = htons (GNUNET_MESSAGE_TYPE_SCALARPRODUCT_BOB_TO_ALICE);
   msg->header.size = htons (msg_length);
-  msg->element_count = htons (request->element_count);
-  msg->used_element_count = htons (request->used_element_count);
+  msg->element_count = htonl (request->element_count);
+  msg->used_element_count = htonl (request->used_element_count);
   memcpy (&msg->key, &request->key, sizeof (struct GNUNET_HashCode));
   current = (unsigned char *) &msg[1];
 
@@ -870,33 +875,24 @@ prepare_service_response (gcry_mpi_t * r,
 
   if (GNUNET_SERVER_MAX_MESSAGE_SIZE >= msg_length)
     {
-      struct MessageObject * msg_obj;
-
-      msg_obj = GNUNET_new (struct MessageObject);
-      msg_obj->msg = (struct GNUNET_MessageHeader *) msg;
-      msg_obj->transmit_handle = (void *) &request->service_transmit_handle; //and reset the transmit handle
+      request->msg = (struct GNUNET_MessageHeader *) msg;
       request->service_transmit_handle =
               GNUNET_MESH_notify_transmit_ready (request->tunnel,
                                                  GNUNET_YES,
                                                  GNUNET_TIME_UNIT_FOREVER_REL,
                                                  msg_length,
                                                  &do_send_message,
-                                                 msg_obj);
+                                                 request);
       // we don't care if it could be send or not. either way, the session is over for us.
       request->state = FINALIZED;
-      response->state = FINALIZED;
     }
   else
-    {
-      // TODO FEATURE: fallback to fragmentation, in case the message is too long
       GNUNET_log (GNUNET_ERROR_TYPE_WARNING, _ ("Message too large, fragmentation is currently not supported!)\n"));
-    }
 
   //disconnect our client
-  if ( ! request->service_transmit_handle)
+  if ( NULL == request->service_transmit_handle)
     {
       GNUNET_log (GNUNET_ERROR_TYPE_ERROR, _ ("Could not send service-response message via mesh!)\n"));
-      GNUNET_CONTAINER_DLL_remove (from_client_head, from_client_tail, response);
       
       response->client_notification_task = 
               GNUNET_SCHEDULER_add_now (&prepare_client_end_notification,
@@ -929,7 +925,7 @@ compute_service_response (struct ServiceSession * request,
   int ret = GNUNET_SYSERR;
   unsigned int * p;
   unsigned int * q;
-  uint16_t count;
+  uint32_t count;
   gcry_mpi_t * rand = NULL;
   gcry_mpi_t * r = NULL;
   gcry_mpi_t * r_prime = NULL;
@@ -1136,11 +1132,10 @@ prepare_service_request (void *cls,
   struct ServiceSession * session = cls;
   unsigned char * current;
   struct GNUNET_SCALARPRODUCT_service_request * msg;
-  struct MessageObject * msg_obj;
   unsigned int i;
   unsigned int j;
-  uint16_t msg_length;
-  size_t element_length = 0; //gets initialized by gcry_mpi_print, but the compiler doesn't know that
+  uint32_t msg_length;
+  size_t element_length = 0; // initialized by gcry_mpi_print, but the compiler doesn't know that
   gcry_mpi_t a;
   uint32_t value;
   
@@ -1158,23 +1153,20 @@ prepare_service_request (void *cls,
       + session->mask_length
       + my_pubkey_external_length)
     {
-      // TODO FEATURE: fallback to fragmentation, in case the message is too long
       GNUNET_log (GNUNET_ERROR_TYPE_WARNING, _ ("Message too large, fragmentation is currently not supported!\n"));
-      GNUNET_CONTAINER_DLL_remove (from_client_head, from_client_tail, session);
-      
       session->client_notification_task = 
               GNUNET_SCHEDULER_add_now (&prepare_client_end_notification,
                                         session);
       return;
     }
+  
   msg = GNUNET_malloc (msg_length);
-
   msg->header.type = htons (GNUNET_MESSAGE_TYPE_SCALARPRODUCT_ALICE_TO_BOB);
   memcpy (&msg->key, &session->key, sizeof (struct GNUNET_HashCode));
-  msg->mask_length = htons (session->mask_length);
-  msg->pk_length = htons (my_pubkey_external_length);
-  msg->used_element_count = htons (session->used_element_count);
-  msg->element_count = htons (session->element_count);
+  msg->mask_length = htonl (session->mask_length);
+  msg->pk_length = htonl (my_pubkey_external_length);
+  msg->used_element_count = htonl (session->used_element_count);
+  msg->element_count = htonl (session->element_count);
   msg->header.size = htons (msg_length);
 
   // fill in the payload
@@ -1226,29 +1218,26 @@ prepare_service_request (void *cls,
     }
   gcry_mpi_release (a);
 
-  msg_obj = GNUNET_new (struct MessageObject);
-  msg_obj->msg = (struct GNUNET_MessageHeader *) msg;
-  msg_obj->transmit_handle = (void *) &session->service_transmit_handle; //and reset the transmit handle
+  session->msg = (struct GNUNET_MessageHeader *) msg;
   GNUNET_log (GNUNET_ERROR_TYPE_INFO, _("Transmitting service request.\n"));
 
   //transmit via mesh messaging
-  session->state = WAITING_FOR_RESPONSE_FROM_SERVICE;
   session->service_transmit_handle = GNUNET_MESH_notify_transmit_ready (session->tunnel, GNUNET_YES,
                                                                         GNUNET_TIME_UNIT_FOREVER_REL,
                                                                         msg_length,
                                                                         &do_send_message,
-                                                                        msg_obj);
+                                                                        session);
   if ( ! session->service_transmit_handle)
     {
       GNUNET_log (GNUNET_ERROR_TYPE_ERROR, _("Could not send mutlicast message to tunnel!\n"));
-      GNUNET_free (msg_obj);
       GNUNET_free (msg);
-      GNUNET_CONTAINER_DLL_remove (from_client_head, from_client_tail, session);
-      
+      session->msg = NULL;
       session->client_notification_task = 
               GNUNET_SCHEDULER_add_now (&prepare_client_end_notification,
                                         session);
+      return;
     }
+  session->state = WAITING_FOR_SERVICE_RESPONSE;
 }
 
 /**
@@ -1268,17 +1257,22 @@ handle_client_request (void *cls,
 {
   const struct GNUNET_SCALARPRODUCT_client_request * msg = (const struct GNUNET_SCALARPRODUCT_client_request *) message;
   struct ServiceSession * session;
-  uint16_t element_count;
-  uint16_t mask_length;
-  uint16_t msg_type;
+  uint32_t element_count;
+  uint32_t mask_length;
+  uint32_t msg_type;
   int32_t * vector;
   uint32_t i;
 
-  GNUNET_SERVER_client_get_user_context (client, session);
-  if (NULL != session){
+  // only one concurrent session per client connection allowed, simplifies logics a lot...
+  session = GNUNET_SERVER_client_get_user_context (client, struct ServiceSession);
+  if ((NULL != session) && (session->state != FINALIZED)){
+    GNUNET_SERVER_receive_done (client, GNUNET_OK);
+    return;
+  }
+  else if(NULL != session){
+    // old session is already completed, clean it up
+    GNUNET_CONTAINER_DLL_remove (from_client_head, from_client_tail, session);
     free_session(session);
-    // FIXME: also terminate active handles and tasks, in it's not finalized
-    GNUNET_SERVER_client_set_user_context (client, NULL);
   }
 
   //we need at least a peer and one message id to compare
@@ -1291,8 +1285,8 @@ handle_client_request (void *cls,
     }
 
   msg_type = ntohs (msg->header.type);
-  element_count = ntohs (msg->element_count);
-  mask_length = ntohs (msg->mask_length);
+  element_count = ntohl (msg->element_count);
+  mask_length = ntohl (msg->mask_length);
 
   //sanity check: is the message as long as the message_count fields suggests?
   if (( ntohs (msg->header.size) != (sizeof (struct GNUNET_SCALARPRODUCT_client_request) + element_count * sizeof (int32_t) + mask_length))
@@ -1318,8 +1312,6 @@ handle_client_request (void *cls,
     }
 
   session = GNUNET_new (struct ServiceSession);
-  //FIXME: this actually should not happen here!
-  GNUNET_SERVER_client_set_user_context (client, session);
   session->service_request_task = GNUNET_SCHEDULER_NO_TASK;
   session->client_notification_task = GNUNET_SCHEDULER_NO_TASK;
   session->client = client;
@@ -1353,11 +1345,10 @@ handle_client_request (void *cls,
             session->used_element_count++;
         }
 
-      if ( ! session->used_element_count)
+      if ( 0 == session->used_element_count)
         {
           GNUNET_break_op (0);
           GNUNET_free (session->vector);
-          GNUNET_free (session->a);
           GNUNET_free (session);
           GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
           return;
@@ -1367,7 +1358,6 @@ handle_client_request (void *cls,
         {
           GNUNET_break (0);
           GNUNET_free (session->vector);
-          GNUNET_free (session->a);
           GNUNET_free (session);
           GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
           return;
@@ -1377,7 +1367,6 @@ handle_client_request (void *cls,
       GNUNET_log (GNUNET_ERROR_TYPE_INFO, 
                  _ ("Creating new tunnel to for session with key %s.\n"), 
                  GNUNET_h2s (&session->key));
-      GNUNET_CONTAINER_DLL_insert (from_client_head, from_client_tail, session);
       session->tunnel = GNUNET_MESH_tunnel_create (my_mesh, session,
                                                    &session->peer,
                                                    GNUNET_APPLICATION_TYPE_SCALARPRODUCT,
@@ -1388,34 +1377,35 @@ handle_client_request (void *cls,
         {
           GNUNET_break (0);
           GNUNET_free (session->vector);
-          GNUNET_free (session->a);
           GNUNET_free (session);
           GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
           return;
         }
-      session->state = WAITING_FOR_BOBS_CONNECT;
+      GNUNET_SERVER_client_set_user_context (client, session);
+      GNUNET_CONTAINER_DLL_insert (from_client_head, from_client_tail, session);
       
+      session->state = CLIENT_REQUEST_RECEIVED;
       session->service_request_task = 
               GNUNET_SCHEDULER_add_now (&prepare_service_request, 
                                         session);
       
-      GNUNET_SERVER_receive_done (client, GNUNET_YES);
     }
   else
     {
       struct ServiceSession * requesting_session;
-      enum SessionState needed_state = REQUEST_FROM_SERVICE_RECEIVED;
-
+      enum SessionState needed_state = SERVICE_REQUEST_RECEIVED;
+      
       session->role = BOB;
       session->mask = NULL;
       // copy over the elements
       session->used_element_count = element_count;
       for (i = 0; i < element_count; i++)
         session->vector[i] = ntohl (vector[i]);
-      session->state = MESSAGE_FROM_RESPONDING_CLIENT_RECEIVED;
+      session->state = CLIENT_RESPONSE_RECEIVED;
       
+      GNUNET_SERVER_client_set_user_context (client, session);
       GNUNET_CONTAINER_DLL_insert (from_client_head, from_client_tail, session);
-      GNUNET_SERVER_receive_done (client, GNUNET_YES);
+      
       //check if service queue contains a matching request 
       requesting_session = find_matching_session (from_service_tail,
                                                   &session->key,
@@ -1425,19 +1415,18 @@ handle_client_request (void *cls,
         {
           GNUNET_log (GNUNET_ERROR_TYPE_INFO, _ ("Got client-responder-session with key %s and a matching service-request-session set, processing.\n"), GNUNET_h2s (&session->key));
           if (GNUNET_OK != compute_service_response (requesting_session, session))
-            {
-              GNUNET_CONTAINER_DLL_remove (from_client_head, from_client_tail, session);
-              
               session->client_notification_task = 
                       GNUNET_SCHEDULER_add_now (&prepare_client_end_notification, 
                                                 session);
-            }
+              
         }
-      else
+      else{
         GNUNET_log (GNUNET_ERROR_TYPE_INFO, _ ("Got client-responder-session with key %s but NO matching service-request-session set, queuing element for later use.\n"), GNUNET_h2s (&session->key));
         // no matching session exists yet, store the response
         // for later processing by handle_service_request()
+      }
     }
+  GNUNET_SERVER_receive_done (client, GNUNET_YES);
 }
 
 
@@ -1462,6 +1451,7 @@ tunnel_incoming_handler (void *cls,
   c->peer = *initiator;
   c->tunnel = tunnel;
   c->role = BOB;
+  c->state = WAITING_FOR_SERVICE_REQUEST;
   return c;
 }
 
@@ -1493,14 +1483,8 @@ tunnel_destruction_handler (void *cls,
   if (ALICE == session->role) {
     // as we have only one peer connected in each session, just remove the session
 
-    if ((FINALIZED != session->state) && (!do_shutdown))
+    if ((SERVICE_RESPONSE_RECEIVED > session->state) && (!do_shutdown))
     {
-      for (curr = from_client_head; NULL != curr; curr = curr->next)
-        if (curr == session)
-        {
-          GNUNET_CONTAINER_DLL_remove (from_client_head, from_client_tail, session);
-          break;
-        }
       session->tunnel = NULL;
       // if this happened before we received the answer, we must terminate the session
       session->client_notification_task = 
@@ -1557,7 +1541,7 @@ static gcry_mpi_t
 compute_scalar_product (struct ServiceSession * session,
                         gcry_mpi_t * r, gcry_mpi_t * r_prime, gcry_mpi_t s, gcry_mpi_t s_prime)
 {
-  uint16_t count;
+  uint32_t count;
   gcry_mpi_t t;
   gcry_mpi_t u;
   gcry_mpi_t utick;
@@ -1644,8 +1628,7 @@ prepare_client_response (void *cls,
   struct GNUNET_SCALARPRODUCT_client_response * msg;
   unsigned char * product_exported = NULL;
   size_t product_length = 0;
-  uint16_t msg_length = 0;
-  struct MessageObject * msg_obj;
+  uint32_t msg_length = 0;
   int8_t range = -1;
   gcry_error_t rc;
   int sign;
@@ -1658,6 +1641,7 @@ prepare_client_response (void *cls,
       
       sign = gcry_mpi_cmp_ui(session->product, 0);
       // libgcrypt can not handle a print of a negative number
+      // if (a->sign) return gcry_error (GPG_ERR_INTERNAL); /* Can't handle it yet. */
       if (0 > sign){
           gcry_mpi_sub(value, value, session->product);
       }
@@ -1668,56 +1652,52 @@ prepare_client_response (void *cls,
       else
         range = 0;
       
+      gcry_mpi_release (session->product);
+      session->product = NULL;
+      
       // get representation as string
-      // unfortunately libgcrypt is too stupid to implement print-support in
-      // signed GCRYMPI_FMT_STD format, and simply asserts in that case.
-      // here is the associated sourcecode:
-      // if (a->sign) return gcry_error (GPG_ERR_INTERNAL); /* Can't handle it yet. */
       if (range
           && (0 != (rc =  gcry_mpi_aprint (GCRYMPI_FMT_USG,
                                              &product_exported,
                                              &product_length,
-                                             session->product)))){
+                                             value)))){
         LOG_GCRY(GNUNET_ERROR_TYPE_ERROR, "gcry_mpi_scan", rc);
         product_length = 0;
         range = -1; // signal error with product-length = 0 and range = -1
       }
-      
-      gcry_mpi_release (session->product);
-      session->product = NULL;
+      gcry_mpi_release (value);
     }
 
   msg_length = sizeof (struct GNUNET_SCALARPRODUCT_client_response) + product_length;
   msg = GNUNET_malloc (msg_length);
-  memcpy (&msg[1], product_exported, product_length);
-  GNUNET_free_non_null (product_exported);
+  memcpy (&msg->key, &session->key, sizeof (struct GNUNET_HashCode));
+  memcpy (&msg->peer, &session->peer, sizeof ( struct GNUNET_PeerIdentity));
+  if (product_exported != NULL){
+    memcpy (&msg[1], product_exported, product_length);
+    GNUNET_free(product_exported);
+  }
   msg->header.type = htons (GNUNET_MESSAGE_TYPE_SCALARPRODUCT_SERVICE_TO_CLIENT);
   msg->header.size = htons (msg_length);
   msg->range = range;
-  memcpy (&msg->key, &session->key, sizeof (struct GNUNET_HashCode));
-  memcpy (&msg->peer, &session->peer, sizeof ( struct GNUNET_PeerIdentity));
   msg->product_length = htonl (product_length);
   
-  msg_obj = GNUNET_new (struct MessageObject);
-  msg_obj->msg = (struct GNUNET_MessageHeader *) msg;
-  msg_obj->transmit_handle = NULL; // don't reset the transmit handle
-
+  session->msg = (struct GNUNET_MessageHeader *) msg;
   //transmit this message to our client
   session->client_transmit_handle = 
           GNUNET_SERVER_notify_transmit_ready (session->client,
                                                msg_length,
                                                GNUNET_TIME_UNIT_FOREVER_REL,
                                                &do_send_message,
-                                               msg_obj);
-  if ( ! session->client_transmit_handle)
+                                               session);
+  if ( NULL == session->client_transmit_handle)
     {
       GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
-                 _ ("Could not send message to client (%p)! This probably is OK if the client disconnected before us.\n"), 
+                 _ ("Could not send message to client (%p)!\n"), 
                  session->client);
       session->client = NULL;
       // callback was not called!
-      GNUNET_free (msg_obj);
       GNUNET_free (msg);
+      session->msg = NULL;
     }
   else
       // gracefully sent message, just terminate session structure
@@ -1748,11 +1728,11 @@ handle_service_request (void *cls,
 {
   struct ServiceSession * session;
   const struct GNUNET_SCALARPRODUCT_service_request * msg = (const struct GNUNET_SCALARPRODUCT_service_request *) message;
-  uint16_t mask_length;
-  uint16_t pk_length;
-  uint16_t used_elements;
-  uint16_t element_count;
-  uint16_t msg_length;
+  uint32_t mask_length;
+  uint32_t pk_length;
+  uint32_t used_elements;
+  uint32_t element_count;
+  uint32_t msg_length;
   unsigned char * current;
   struct ServiceSession * responder_session;
   int32_t i = -1;
@@ -1772,22 +1752,22 @@ handle_service_request (void *cls,
   // Check if message was sent by me, which would be bad!
   if ( ! memcmp (&session->peer, &me, sizeof (struct GNUNET_PeerIdentity)))
     {
-      GNUNET_break (0);
       GNUNET_free (session);
+      GNUNET_break (0);
       return GNUNET_SYSERR;
     }
 
   //we need at least a peer and one message id to compare
   if (ntohs (msg->header.size) < sizeof (struct GNUNET_SCALARPRODUCT_service_request))
     {
-      GNUNET_log (GNUNET_ERROR_TYPE_WARNING, _ ("Too short message received from peer!\n"));
       GNUNET_free (session);
+      GNUNET_break_op(0);
       return GNUNET_SYSERR;
     }
-  mask_length = ntohs (msg->mask_length);
-  pk_length = ntohs (msg->pk_length);
-  used_elements = ntohs (msg->used_element_count);
-  element_count = ntohs (msg->element_count);
+  mask_length = ntohl (msg->mask_length);
+  pk_length = ntohl (msg->pk_length);
+  used_elements = ntohl (msg->used_element_count);
+  element_count = ntohl (msg->element_count);
   msg_length = sizeof (struct GNUNET_SCALARPRODUCT_service_request)
                + mask_length + pk_length + used_elements * PAILLIER_ELEMENT_LENGTH;
 
@@ -1796,9 +1776,8 @@ handle_service_request (void *cls,
       || (used_elements == 0) || (mask_length != (element_count / 8 + (element_count % 8 ? 1 : 0)))
       )
     {
-      GNUNET_log (GNUNET_ERROR_TYPE_WARNING, _ ("Invalid message received from peer, message count does not match message length!\n"));
-      GNUNET_log (GNUNET_ERROR_TYPE_WARNING, _ ("Used elements: %hu\nElement Count: %hu\nExpected Mask Length: %hu\nCalculated Masklength: %d\n"), used_elements, element_count, mask_length, (element_count / 8 + (element_count % 8 ? 1 : 0)));
       GNUNET_free (session);
+      GNUNET_break_op(0);
       return GNUNET_SYSERR;
     }
   if (find_matching_session (from_service_tail,
@@ -1813,8 +1792,8 @@ handle_service_request (void *cls,
     }
   
   memcpy (&session->peer, &session->peer, sizeof (struct GNUNET_PeerIdentity));
-  session->state = REQUEST_FROM_SERVICE_RECEIVED;
-  session->element_count = ntohs (msg->element_count);
+  session->state = SERVICE_REQUEST_RECEIVED;
+  session->element_count = ntohl (msg->element_count);
   session->used_element_count = used_elements;
   session->tunnel = tunnel;
 
@@ -1839,7 +1818,7 @@ handle_service_request (void *cls,
   current += pk_length;
 
   //check if service queue contains a matching request 
-  needed_state = MESSAGE_FROM_RESPONDING_CLIENT_RECEIVED;
+  needed_state = CLIENT_RESPONSE_RECEIVED;
   responder_session = find_matching_session (from_client_tail,
                                              &session->key,
                                              session->element_count,
@@ -1884,6 +1863,7 @@ handle_service_request (void *cls,
         }
       else
           GNUNET_log (GNUNET_ERROR_TYPE_INFO, _ ("Got session with key %s without a matching element set, queueing.\n"), GNUNET_h2s (&session->key));
+      
       return GNUNET_OK;
     }
   else
@@ -1903,13 +1883,10 @@ except:
   free_session (session);
   // and notify our client-session that we could not complete the session
   if (responder_session)
-    {
       // we just found the responder session in this queue
-      GNUNET_CONTAINER_DLL_remove (from_client_head, from_client_tail, responder_session);
       responder_session->client_notification_task = 
               GNUNET_SCHEDULER_add_now (&prepare_client_end_notification,
                                         responder_session);
-    }
   return GNUNET_SYSERR;
 }
 
@@ -1935,12 +1912,12 @@ handle_service_response (void *cls,
   struct ServiceSession * session;
   const struct GNUNET_SCALARPRODUCT_service_response * msg = (const struct GNUNET_SCALARPRODUCT_service_response *) message;
   unsigned char * current;
-  uint16_t count;
+  uint32_t count;
   gcry_mpi_t s = NULL;
   gcry_mpi_t s_prime = NULL;
   size_t read;
   size_t i;
-  uint16_t used_element_count;
+  uint32_t used_element_count;
   size_t msg_size;
   gcry_mpi_t * r = NULL;
   gcry_mpi_t * r_prime = NULL;
@@ -1955,6 +1932,7 @@ handle_service_response (void *cls,
   
   count = session->used_element_count;
   session->product = NULL;
+  session->state = SERVICE_RESPONSE_RECEIVED;
 
   //we need at least a peer and one message id to compare
   if (sizeof (struct GNUNET_SCALARPRODUCT_service_response) > ntohs (msg->header.size))
@@ -1962,7 +1940,7 @@ handle_service_response (void *cls,
       GNUNET_break_op (0);
       goto invalid_msg;
     }
-  used_element_count = ntohs (msg->used_element_count);
+  used_element_count = ntohl (msg->used_element_count);
   msg_size = sizeof (struct GNUNET_SCALARPRODUCT_service_response)
           + 2 * used_element_count * PAILLIER_ELEMENT_LENGTH
           + 2 * PAILLIER_ELEMENT_LENGTH;
@@ -2001,7 +1979,7 @@ handle_service_response (void *cls,
                            PAILLIER_ELEMENT_LENGTH, &read)))
         {
           LOG_GCRY (GNUNET_ERROR_TYPE_DEBUG, "gcry_mpi_scan", rc);
-      GNUNET_break_op (0);
+          GNUNET_break_op (0);
           goto invalid_msg;
         }
       current += PAILLIER_ELEMENT_LENGTH;
@@ -2016,12 +1994,11 @@ handle_service_response (void *cls,
                            PAILLIER_ELEMENT_LENGTH, &read)))
         {
           LOG_GCRY (GNUNET_ERROR_TYPE_DEBUG, "gcry_mpi_scan", rc);
-      GNUNET_break_op (0);
+          GNUNET_break_op (0);
           goto invalid_msg;
         }
       current += PAILLIER_ELEMENT_LENGTH;
     }
-  
   session->product = compute_scalar_product (session, r, r_prime, s, s_prime);
   
 invalid_msg:
@@ -2036,16 +2013,14 @@ invalid_msg:
   GNUNET_free_non_null (r);
   GNUNET_free_non_null (r_prime);
   
-  session->state = FINALIZED;
-  // the tunnel has done its job, terminate our connection and the tunnel
-  // the peer will be notified that the tunnel was destroyed via tunnel_destruction_handler
-  GNUNET_CONTAINER_DLL_remove (from_client_head, from_client_tail, session);
+  session->tunnel = NULL;
   // send message with product to client
-  
   session->client_notification_task = 
-          GNUNET_SCHEDULER_add_now (&prepare_client_response, 
-          session);
-  // just close the connection.
+             GNUNET_SCHEDULER_add_now (&prepare_client_response, 
+                                        session);
+  // the tunnel has done its job, terminate our connection and the tunnel
+  // the peer will be notified that the tunnel was destroyed via tunnel_destruction_handler
+  // just close the connection, as recommended by Christian
   return GNUNET_SYSERR;
 }