X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=src%2Ftestbed%2Fgnunet-service-testbed_links.c;h=766c47471342f36919a906324d521bfc23cd8e59;hb=27c12911f4f2aba2d90099270d70de846e83854f;hp=6f71d8a611ee7c0a5a3d2daa7f864f9c8d74966b;hpb=dd2b8d87339226bb3e9a04f7111561740328c40e;p=oweals%2Fgnunet.git

diff --git a/src/testbed/gnunet-service-testbed_links.c b/src/testbed/gnunet-service-testbed_links.c
index 6f71d8a61..766c47471 100644
--- a/src/testbed/gnunet-service-testbed_links.c
+++ b/src/testbed/gnunet-service-testbed_links.c
@@ -4,7 +4,7 @@
 
   GNUnet is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published
-  by the Free Software Foundation; either version 2, or (at your
+  by the Free Software Foundation; either version 3, or (at your
   option) any later version.
 
   GNUnet is distributed in the hope that it will be useful, but
@@ -19,18 +19,276 @@
 */
 
 /**
- * @file testbed/gnunet-service-testbed.c
- * @brief implementation of the TESTBED service
+ * @file testbed/gnunet-service-testbed_links.c
+ * @brief TESTBED service components that deals with starting slave controllers
+ *          and establishing lateral links between controllers
  * @author Sree Harsha Totakura
  */
 
 #include "gnunet-service-testbed.h"
 
+/**
+ * Redefine LOG with a changed log component string
+ */
+#ifdef LOG
+#undef LOG
+#endif
+#define LOG(kind,...)                                   \
+  GNUNET_log_from (kind, "testbed-links", __VA_ARGS__)
+
 /**
  * The event mask for the events we listen from sub-controllers
  */
 #define EVENT_MASK (1LL << GNUNET_TESTBED_ET_OPERATION_FINISHED)
 
+
+/**
+ * States of LCFContext
+ */
+enum LCFContextState
+{
+  /**
+   * The Context has been initialized; Nothing has been done on it
+   */
+  INIT,
+
+  /**
+   * Delegated host has been registered at the forwarding controller
+   */
+  DELEGATED_HOST_REGISTERED,
+
+  /**
+   * The slave host has been registred at the forwarding controller
+   */
+  SLAVE_HOST_REGISTERED,
+
+  /**
+   * The context has been finished (may have error)
+   */
+  FINISHED
+};
+
+
+/**
+ * Link controllers request forwarding context
+ */
+struct LCFContext
+{
+  /**
+   * The gateway which will pass the link message to delegated host
+   */
+  struct Slave *gateway;
+
+  /**
+   * The client which has asked to perform this operation
+   */
+  struct GNUNET_SERVER_Client *client;
+
+  /**
+   * Handle for operations which are forwarded while linking controllers
+   */
+  struct GNUNET_TESTBED_Operation *op;
+
+  /**
+   * The timeout task
+   */
+  GNUNET_SCHEDULER_TaskIdentifier timeout_task;
+
+  /**
+   * The id of the operation which created this context
+   */
+  uint64_t operation_id;
+
+  /**
+   * should the slave controller start the delegated controller?
+   */
+  int is_subordinate;
+
+  /**
+   * The state of this context
+   */
+  enum LCFContextState state;
+
+  /**
+   * The delegated host
+   */
+  uint32_t delegated_host_id;
+
+  /**
+   * The slave host
+   */
+  uint32_t slave_host_id;
+
+};
+
+
+/**
+ * Structure of a queue entry in LCFContext request queue
+ */
+struct LCFContextQueue
+{
+  /**
+   * The LCFContext
+   */
+  struct LCFContext *lcf;
+
+  /**
+   * Head prt for DLL
+   */
+  struct LCFContextQueue *next;
+
+  /**
+   * Tail ptr for DLL
+   */
+  struct LCFContextQueue *prev;
+};
+
+
+/**
+ * Notification context to be used to notify when connection to the neighbour's
+ * controller is opened
+ */
+struct NeighbourConnectNotification
+{
+  /**
+   * DLL next for inclusion in neighbour's list of notification requests
+   */
+  struct NeighbourConnectNotification *next;
+
+  /**
+   * DLL prev
+   */
+  struct NeighbourConnectNotification *prev;
+
+  /**
+   * The neighbour
+   */
+  struct Neighbour *n;
+
+  /**
+   * The notification callback to call when we are connect to neighbour
+   */
+  GST_NeigbourConnectNotifyCallback cb;
+
+  /**
+   * The closure for the above callback
+   */
+  void *cb_cls;
+};
+
+
+/**
+ * A connected controller which is not our child
+ */
+struct Neighbour
+{
+  /**
+   * The controller handle
+   */
+  struct GNUNET_TESTBED_Controller *controller;
+
+  /**
+   * Operation handle for opening a lateral connection to another controller.
+   * Will be NULL if the slave controller is started by this controller
+   */
+  struct GNUNET_TESTBED_Operation *conn_op;
+
+  /**
+   * DLL head for the list of notification requests
+   */
+  struct NeighbourConnectNotification *nl_head;
+
+  /**
+   * DLL tail for the list of notification requests
+   */
+  struct NeighbourConnectNotification *nl_tail;
+
+  /**
+   * Task id for the task to call notifications from the notification list
+   */
+  GNUNET_SCHEDULER_TaskIdentifier notify_task;
+
+  /**
+   * How many references are present currently to this neighbour's connection
+   */
+  unsigned int reference_cnt;
+
+  /**
+   * Is the conn_op inactivated?
+   */
+  unsigned int inactive;
+
+  /**
+   * The id of the host this controller is running on
+   */
+  uint32_t host_id;
+};
+
+
+/**
+ * The neighbour list
+ */
+static struct Neighbour **neighbour_list;
+
+/**
+ * The size of the neighbour list
+ */
+static unsigned int neighbour_list_size;
+
+
+/**
+ * Context information for establishing a link to neighbour (Used is
+ * GST_handle_link_controllers()
+ */
+struct NeighbourConnectCtxt
+{
+  /**
+   * DLL next for inclusion in the corresponding context list
+   */
+  struct NeighbourConnectCtxt *next;
+
+  /**
+   * DLL tail
+   */
+  struct NeighbourConnectCtxt *prev;
+
+  /**
+   * The neighbour to whom connection should be made
+   */
+  struct Neighbour *n;
+
+  /**
+   * The client requesting the connection
+   */
+  struct GNUNET_SERVER_Client *client;
+
+  /**
+   * Task to be run upon timeout
+   */
+  GNUNET_SCHEDULER_TaskIdentifier timeout_task;
+
+  /**
+   * The notification handle associated with the neighbour's connection request
+   */
+  struct NeighbourConnectNotification *nh;
+
+  /**
+   * The id of the link-controllers operation responsible for creating this
+   * context
+   */
+  uint64_t op_id;
+};
+
+/**
+ * DLL head for the list of neighbour connect contexts
+ */
+struct NeighbourConnectCtxt *ncc_head;
+
+/**
+ * DLL tail for the list of neighbour connect contexts
+ */
+struct NeighbourConnectCtxt *ncc_tail;
+
 /**
  * A list of directly linked neighbours
  */
@@ -98,6 +356,22 @@ route_list_add (struct Route *route)
 }
 
 
+/**
+ * Add a neighbour to the neighbour list.  Grows the neighbour list
+ * automatically.
+ *
+ * @param n the neighbour to add
+ */
+static void
+neighbour_list_add (struct Neighbour *n)
+{
+  if (n->host_id >= neighbour_list_size)
+    GST_array_grow_large_enough (neighbour_list, neighbour_list_size, n->host_id);
+  GNUNET_assert (NULL == neighbour_list[n->host_id]);
+  neighbour_list[n->host_id] = n;
+}
+
+
 /**
  * Cleans up the route list
  */
@@ -105,7 +379,7 @@ void
 GST_route_list_clear ()
 {
   unsigned int id;
-  
+
   for (id = 0; id < route_list_size; id++)
     if (NULL != route_list[id])
       GNUNET_free (route_list[id]);
@@ -140,47 +414,85 @@ reghost_free_iterator (void *cls, const struct GNUNET_HashCode *key,
     GNUNET_CONTAINER_DLL_remove (rhc->focc_dll_head, rhc->focc_dll_tail, focc);
     GST_cleanup_focc (focc);
   }
-  if (NULL != rhc->sub_op)
-    GNUNET_TESTBED_operation_done (rhc->sub_op);
-  if (NULL != rhc->client)
-    GNUNET_SERVER_client_drop (rhc->client);
   GNUNET_free (value);
   return GNUNET_YES;
 }
 
 
+/**
+ * Kill a #Slave object
+ *
+ * @param slave the #Slave object
+ */
+static void
+kill_slave (struct Slave *slave)
+{
+  struct HostRegistration *hr_entry;
+
+  while (NULL != (hr_entry = slave->hr_dll_head))
+  {
+    GNUNET_CONTAINER_DLL_remove (slave->hr_dll_head, slave->hr_dll_tail,
+                                 hr_entry);
+    GNUNET_free (hr_entry);
+  }
+  if (NULL != slave->rhandle)
+    GNUNET_TESTBED_cancel_registration (slave->rhandle);
+  GNUNET_assert (GNUNET_SYSERR !=
+                 GNUNET_CONTAINER_multihashmap_iterate (slave->reghost_map,
+                                                        reghost_free_iterator,
+                                                        slave));
+  GNUNET_CONTAINER_multihashmap_destroy (slave->reghost_map);
+  if (NULL != slave->controller)
+    GNUNET_TESTBED_controller_disconnect (slave->controller);
+  if (NULL != slave->controller_proc)
+  {
+    LOG_DEBUG ("Stopping a slave\n");
+    GNUNET_TESTBED_controller_kill_ (slave->controller_proc);
+  }
+}
+
+
+/**
+ * Destroy a #Slave object
+ *
+ * @param slave the #Slave object
+ */
+static void
+destroy_slave (struct Slave *slave)
+{
+  if (NULL != slave->controller_proc)
+  {
+    GNUNET_TESTBED_controller_destroy_ (slave->controller_proc);
+    LOG_DEBUG ("Slave stopped\n");
+  }
+  GST_slave_list[slave->host_id] = NULL;
+  GNUNET_free (slave);
+}
+
+
 /**
  * Cleans up the slave list
  */
 void
 GST_slave_list_clear ()
 {
+  struct Slave *slave;
   unsigned int id;
-  struct HostRegistration *hr_entry;
 
   for (id = 0; id < GST_slave_list_size; id++)
-    if (NULL != GST_slave_list[id])
-    {
-      while (NULL != (hr_entry = GST_slave_list[id]->hr_dll_head))
-      {
-        GNUNET_CONTAINER_DLL_remove (GST_slave_list[id]->hr_dll_head,
-                                     GST_slave_list[id]->hr_dll_tail, hr_entry);
-        GNUNET_free (hr_entry);
-      }
-      if (NULL != GST_slave_list[id]->rhandle)
-        GNUNET_TESTBED_cancel_registration (GST_slave_list[id]->rhandle);
-      (void)
-          GNUNET_CONTAINER_multihashmap_iterate (GST_slave_list
-                                                 [id]->reghost_map,
-                                                 reghost_free_iterator,
-                                                 GST_slave_list[id]);
-      GNUNET_CONTAINER_multihashmap_destroy (GST_slave_list[id]->reghost_map);
-      if (NULL != GST_slave_list[id]->controller)
-        GNUNET_TESTBED_controller_disconnect (GST_slave_list[id]->controller);
-      if (NULL != GST_slave_list[id]->controller_proc)
-        GNUNET_TESTBED_controller_stop (GST_slave_list[id]->controller_proc);
-      GNUNET_free (GST_slave_list[id]);
-    }
+  {
+    slave = GST_slave_list[id];
+    if (NULL == slave)
+      continue;
+    kill_slave (slave);
+  }
+  for (id = 0; id < GST_slave_list_size; id++)
+  {
+    slave = GST_slave_list[id];
+    if (NULL == slave)
+      continue;
+    destroy_slave (slave);
+  }
   GNUNET_free_non_null (GST_slave_list);
   GST_slave_list = NULL;
 }
@@ -233,7 +545,7 @@ send_controller_link_response (struct GNUNET_SERVER_Client *client,
   struct GNUNET_TESTBED_ControllerLinkResponse *msg;
   char *xconfig;
   size_t config_size;
-  size_t xconfig_size;  
+  size_t xconfig_size;
   uint16_t msize;
 
   GNUNET_assert ((NULL == cfg) || (NULL == emsg));
@@ -259,7 +571,10 @@ send_controller_link_response (struct GNUNET_SERVER_Client *client,
   msg->operation_id = GNUNET_htonll (operation_id);
   msg->config_size = htons ((uint16_t) config_size);
   if (NULL != xconfig)
+  {
     memcpy (&msg[1], xconfig, xconfig_size);
+    GNUNET_free (xconfig);
+  }
   if (NULL != emsg)
     memcpy (&msg[1], emsg, strlen (emsg));
   GST_queue_message (client, &msg->header);
@@ -398,7 +713,6 @@ lcf_proc_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
                                               lcf->gateway->controller,
                                               GST_host_list[lcf->delegated_host_id],
                                               GST_host_list[lcf->slave_host_id],
-                                              NULL,
                                               lcf->is_subordinate);
     lcf->timeout_task =
         GNUNET_SCHEDULER_add_delayed (GST_timeout, &lcf_forwarded_operation_timeout,
@@ -408,10 +722,9 @@ lcf_proc_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
   case FINISHED:
     lcfq = lcfq_head;
     GNUNET_assert (lcfq->lcf == lcf);
-    GNUNET_assert (NULL != lcf->cfg);
-    GNUNET_CONFIGURATION_destroy (lcf->cfg);
     GNUNET_SERVER_client_drop (lcf->client);
-    GNUNET_TESTBED_operation_done (lcf->op);
+    if (NULL != lcf->op)
+      GNUNET_TESTBED_operation_done (lcf->op);
     GNUNET_free (lcf);
     GNUNET_CONTAINER_DLL_remove (lcfq_head, lcfq_tail, lcfq);
     GNUNET_free (lcfq);
@@ -425,70 +738,35 @@ lcf_proc_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
 /**
  * Callback for event from slave controllers
  *
- * @param cls struct Slave *
+ * @param cls NULL
  * @param event information about the event
  */
 static void
-slave_event_callback (void *cls,
-                      const struct GNUNET_TESTBED_EventInformation *event)
+slave_event_cb (void *cls, const struct GNUNET_TESTBED_EventInformation *event)
 {
-  struct RegisteredHostContext *rhc;
   struct LCFContext *lcf;
-  struct GNUNET_CONFIGURATION_Handle *cfg;
-  struct GNUNET_TESTBED_Operation *old_op;
 
-  /* We currently only get here when working on RegisteredHostContexts and
-     LCFContexts */
+  /* We currently only get here when working on LCFContexts */
   GNUNET_assert (GNUNET_TESTBED_ET_OPERATION_FINISHED == event->type);
-  rhc = event->op_cls;
-  if (CLOSURE_TYPE_RHC == rhc->type)
-  {
-    GNUNET_assert (rhc->sub_op == event->op);
-    switch (rhc->state)
-    {
-    case RHC_GET_CFG:
-      cfg = event->details.operation_finished.generic;
-      old_op = rhc->sub_op;
-      rhc->state = RHC_LINK;
-      rhc->sub_op =
-          GNUNET_TESTBED_controller_link (rhc, rhc->gateway->controller,
-                                          rhc->reg_host, rhc->host, cfg,
-                                          GNUNET_NO);
-      GNUNET_TESTBED_operation_done (old_op);
-      break;
-    case RHC_LINK:
-      LOG_DEBUG ("OL: Linking controllers successfull\n");
-      GNUNET_TESTBED_operation_done (rhc->sub_op);
-      rhc->sub_op = NULL;
-      rhc->state = RHC_OL_CONNECT;
-      GST_process_next_focc (rhc);
-      break;
-    default:
-      GNUNET_assert (0);
-    }
-    return;
-  }
   lcf = event->op_cls;
-  if (CLOSURE_TYPE_LCF == lcf->type)
-  {    
-    GNUNET_assert (lcf->op == event->op);
-    GNUNET_assert (FINISHED == lcf->state);
-    GNUNET_assert (GNUNET_SCHEDULER_NO_TASK != lcf->timeout_task);
-    GNUNET_SCHEDULER_cancel (lcf->timeout_task);
-    if (NULL == event->details.operation_finished.emsg)
-      send_controller_link_response (lcf->client, lcf->operation_id,
-                                     GNUNET_TESTBED_host_get_cfg_ 
-                                     (GST_host_list[lcf->delegated_host_id]),
-                                     NULL);
-    else
-      send_controller_link_response (lcf->client, lcf->operation_id,
-                                     NULL,
-                                     event->details.operation_finished.emsg);
-    GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == lcf_proc_task_id);
-    lcf_proc_task_id = GNUNET_SCHEDULER_add_now (&lcf_proc_task, lcf);
-    return;
-  }
-  GNUNET_assert (0);
+  GNUNET_assert (lcf->op == event->op);
+  GNUNET_TESTBED_operation_done (lcf->op);
+  lcf->op = NULL;
+  GNUNET_assert (FINISHED == lcf->state);
+  GNUNET_assert (GNUNET_SCHEDULER_NO_TASK != lcf->timeout_task);
+  GNUNET_SCHEDULER_cancel (lcf->timeout_task);
+  if (NULL == event->details.operation_finished.emsg)
+    send_controller_link_response (lcf->client, lcf->operation_id,
+                                   GNUNET_TESTBED_host_get_cfg_
+                                   (GST_host_list[lcf->delegated_host_id]),
+                                   NULL);
+  else
+    send_controller_link_response (lcf->client, lcf->operation_id,
+                                   NULL,
+                                   event->details.operation_finished.emsg);
+  GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == lcf_proc_task_id);
+  lcf_proc_task_id = GNUNET_SCHEDULER_add_now (&lcf_proc_task, lcf);
+  return;
 }
 
 
@@ -502,8 +780,8 @@ slave_event_callback (void *cls,
  *          GNUNET_TESTBED_controller_stop() shouldn't be called in this case
  */
 static void
-slave_status_callback (void *cls, const struct GNUNET_CONFIGURATION_Handle *cfg,
-                       int status)
+slave_status_cb (void *cls, const struct GNUNET_CONFIGURATION_Handle *cfg,
+                 int status)
 {
   struct Slave *slave = cls;
   struct LinkControllersContext *lcc;
@@ -512,16 +790,21 @@ slave_status_callback (void *cls, const struct GNUNET_CONFIGURATION_Handle *cfg,
   if (GNUNET_SYSERR == status)
   {
     slave->controller_proc = NULL;
-    GST_slave_list[slave->host_id] = NULL;
-    GNUNET_free (slave);
+    /* Stop all link controller forwarding tasks since we shutdown here anyway
+       and as these tasks they depend on the operation queues which are created
+       through GNUNET_TESTBED_controller_connect() and in kill_slave() we call
+       the destructor function GNUNET_TESTBED_controller_disconnect() */
+    GST_free_lcfq ();
+    kill_slave (slave);
+    destroy_slave (slave);
     slave = NULL;
     LOG (GNUNET_ERROR_TYPE_WARNING, "Unexpected slave shutdown\n");
     GNUNET_SCHEDULER_shutdown ();       /* We too shutdown */
     goto clean_lcc;
   }
   slave->controller =
-      GNUNET_TESTBED_controller_connect (cfg, GST_host_list[slave->host_id],
-                                         EVENT_MASK, &slave_event_callback,
+      GNUNET_TESTBED_controller_connect (GST_host_list[slave->host_id],
+                                         EVENT_MASK, &slave_event_cb,
                                          slave);
   if (NULL != slave->controller)
   {
@@ -531,13 +814,12 @@ slave_status_callback (void *cls, const struct GNUNET_CONFIGURATION_Handle *cfg,
   {
     send_controller_link_response (lcc->client, lcc->operation_id, NULL,
                                    "Could not connect to delegated controller");
-    GNUNET_TESTBED_controller_stop (slave->controller_proc);
-    GST_slave_list[slave->host_id] = NULL;
-    GNUNET_free (slave);
+    kill_slave (slave);
+    destroy_slave (slave);
     slave = NULL;
   }
 
-clean_lcc:
+ clean_lcc:
   if (NULL != lcc)
   {
     if (NULL != lcc->client)
@@ -553,6 +835,341 @@ clean_lcc:
 }
 
 
+/**
+ * Trigger notification task if there are notification requests currently
+ * waiting in the given neighbour.  Also activates the neighbour connect operation
+ * if it was previously inactivated so that the connection to the neighbour can
+ * be re-used
+ *
+ * @param n the neighbour
+ */
+static void
+trigger_notifications (struct Neighbour *n);
+
+
+/**
+ * Task to call the notification queued in the notifications list of the given
+ * neighbour
+ *
+ * @param cls the neighbour
+ * @param tc scheduler task context
+ */
+static void
+neighbour_connect_notify_task (void *cls,
+                               const struct GNUNET_SCHEDULER_TaskContext *tc)
+{
+  struct Neighbour *n = cls;
+  struct NeighbourConnectNotification *h;
+
+  GNUNET_assert (NULL != (h = n->nl_head));
+  GNUNET_assert (GNUNET_SCHEDULER_NO_TASK != n->notify_task);
+  n->notify_task = GNUNET_SCHEDULER_NO_TASK;
+  GNUNET_assert (NULL != n->controller);
+  GNUNET_CONTAINER_DLL_remove (n->nl_head, n->nl_tail, h);
+  trigger_notifications (n);
+  h->cb (h->cb_cls, n->controller);
+  GNUNET_free (h);
+}
+
+
+/**
+ * Trigger notification task if there are notification requests currently
+ * waiting in the given neighbour.  Also activates the neighbour connect operation
+ * if it was previously inactivated so that the connection to the neighbour can
+ * be re-used
+ *
+ * @param n the neighbour
+ */
+static void
+trigger_notifications (struct Neighbour *n)
+{
+  GNUNET_assert (NULL != n->conn_op);
+  if (NULL == n->nl_head)
+    return;
+  if (NULL == n->controller)
+    return;
+  if (GNUNET_SCHEDULER_NO_TASK != n->notify_task)
+    return;
+  if (1 == n->inactive)
+  {
+    GNUNET_assert (0 == n->reference_cnt);
+    GNUNET_TESTBED_operation_activate_ (n->conn_op);
+    n->inactive = 0;
+  }
+  n->reference_cnt++;
+  n->notify_task =
+      GNUNET_SCHEDULER_add_now (&neighbour_connect_notify_task, n);
+}
+
+
+/**
+ * Callback to be called when the neighbour connect operation is started.  The
+ * connection to the neigbour is opened here and any pending notifications are
+ * trigger.
+ *
+ * @param cls the neighbour
+ */
+static void
+opstart_neighbour_conn (void *cls)
+{
+  struct Neighbour *n = cls;
+
+  GNUNET_assert (NULL != n->conn_op);
+  GNUNET_assert (NULL == n->controller);
+  LOG_DEBUG ("Opening connection to controller on host %u\n", n->host_id);
+  n->controller = GNUNET_TESTBED_controller_connect (GST_host_list[n->host_id],
+                                                     EVENT_MASK,
+                                                     &slave_event_cb,
+                                                     NULL);
+  trigger_notifications (n);
+}
+
+
+/**
+ * Callback to be called when the neighbour connect operation is released
+ *
+ * @param cls the neighbour
+ */
+static void
+oprelease_neighbour_conn (void *cls)
+{
+   struct Neighbour *n = cls;
+
+   GNUNET_assert (0 == n->reference_cnt);
+   GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == n->notify_task);
+   GNUNET_assert (NULL == n->nl_head);
+   if (NULL != n->controller)
+   {
+     LOG_DEBUG ("Closing connection to controller on host %u\n", n->host_id);
+     GNUNET_TESTBED_controller_disconnect (n->controller);
+     n->controller = NULL;
+   }
+   n->conn_op = NULL;
+   n->inactive = 0;
+}
+
+
+/**
+ * Try to open a connection to the given neigbour.  If the connection is open
+ * already, then it is re-used.  If not, the request is queued in the operation
+ * queues responsible for bounding the total number of file descriptors.  The
+ * actual connection will happen when the operation queue marks the
+ * corresponding operation as active.
+ *
+ * @param n the neighbour to open a connection to
+ * @param cb the notification callback to call when the connection is opened
+ * @param cb_cls the closure for the above callback
+ */
+struct NeighbourConnectNotification *
+GST_neighbour_get_connection (struct Neighbour *n,
+                              GST_NeigbourConnectNotifyCallback cb,
+                              void *cb_cls)
+{
+  struct NeighbourConnectNotification *h;
+
+  GNUNET_assert (NULL != cb);
+  LOG_DEBUG ("Attempting to get connection to controller on host %u\n",
+             n->host_id);
+  h = GNUNET_malloc (sizeof (struct NeighbourConnectNotification));
+  h->n = n;
+  h->cb  = cb;
+  h->cb_cls = cb_cls;
+  GNUNET_CONTAINER_DLL_insert_tail (n->nl_head, n->nl_tail, h);
+  if (NULL == n->conn_op)
+  {
+    GNUNET_assert (NULL == n->controller);
+    n->conn_op = GNUNET_TESTBED_operation_create_ (n, &opstart_neighbour_conn,
+                                                   &oprelease_neighbour_conn);
+    GNUNET_TESTBED_operation_queue_insert_ (GST_opq_openfds, n->conn_op);
+    GNUNET_TESTBED_operation_begin_wait_ (n->conn_op);
+    return h;
+  }
+  trigger_notifications (n);
+  return h;
+}
+
+
+/**
+ * Cancel the request for opening a connection to the neighbour
+ *
+ * @param h the notification handle
+ */
+void
+GST_neighbour_get_connection_cancel (struct NeighbourConnectNotification *h)
+{
+  struct Neighbour *n;
+  int cleanup_task;
+
+  n = h->n;
+  cleanup_task = (h == n->nl_head) ? GNUNET_YES : GNUNET_NO;
+  GNUNET_CONTAINER_DLL_remove (n->nl_head, n->nl_tail, h);
+  GNUNET_free (h);
+  if (GNUNET_NO == cleanup_task)
+    return;
+  if (GNUNET_SCHEDULER_NO_TASK == n->notify_task)
+    return;
+  GNUNET_assert (0 < n->reference_cnt);
+  n->reference_cnt--;
+  GNUNET_SCHEDULER_cancel (n->notify_task);
+  n->notify_task = GNUNET_SCHEDULER_NO_TASK;
+  if (NULL == n->nl_head)
+  {
+    if ( (0 == n->reference_cnt) && (0 == n->inactive) )
+    {
+      n->inactive = 1;
+      GNUNET_TESTBED_operation_inactivate_ (n->conn_op);
+    }
+    return;
+  }
+  trigger_notifications (n);
+}
+
+
+/**
+ * Release the connection to the neighbour.  The actual connection will be
+ * closed if connections to other neighbour are waiting (to maintain a bound on
+ * the total number of connections that are open).
+ *
+ * @param n the neighbour whose connection can be closed
+ */
+void
+GST_neighbour_release_connection (struct Neighbour *n)
+{
+  GNUNET_assert (0 == n->inactive);
+  GNUNET_assert (0 < n->reference_cnt);
+  n->reference_cnt--;
+  if (0 == n->reference_cnt)
+  {
+    n->inactive = 1;
+    GNUNET_TESTBED_operation_inactivate_ (n->conn_op);
+  }
+}
+
+
+/**
+ * Cleanup neighbour connect contexts
+ *
+ * @param ncc the neighbour connect context to cleanup
+ */
+static void
+cleanup_ncc (struct NeighbourConnectCtxt *ncc)
+{
+  if (NULL != ncc->nh)
+    GST_neighbour_get_connection_cancel (ncc->nh);
+  if (GNUNET_SCHEDULER_NO_TASK != ncc->timeout_task)
+    GNUNET_SCHEDULER_cancel (ncc->timeout_task);
+  GNUNET_SERVER_client_drop (ncc->client);
+  GNUNET_CONTAINER_DLL_remove (ncc_head, ncc_tail, ncc);
+  GNUNET_free (ncc);
+}
+
+
+/**
+ * Cleans up the neighbour list
+ */
+void
+GST_neighbour_list_clean()
+{
+  struct Neighbour *n;
+  unsigned int id;
+
+  for (id = 0; id < neighbour_list_size; id++)
+  {
+    if (NULL == (n = neighbour_list[id]))
+      continue;
+    if (NULL != n->conn_op)
+      GNUNET_TESTBED_operation_release_ (n->conn_op);
+    GNUNET_free (n);
+    neighbour_list[id] = NULL;
+  }
+  GNUNET_free_non_null (neighbour_list);
+}
+
+
+/**
+ * Get a neighbour from the neighbour list
+ *
+ * @param id the index of the neighbour in the neighbour list
+ * @return the Neighbour; NULL if the given index in invalid (index greater than
+ *           the list size or neighbour at that index is NULL)
+ */
+struct Neighbour *
+GST_get_neighbour (uint32_t id)
+{
+  if (neighbour_list_size <= id)
+    return NULL;
+  else
+    return neighbour_list[id];
+}
+
+
+/**
+ * Function to cleanup the neighbour connect contexts
+ */
+void
+GST_free_nccq ()
+{
+  while (NULL != ncc_head)
+    cleanup_ncc (ncc_head);
+}
+
+
+/**
+ * Task to be run upon timeout while attempting to connect to the neighbour
+ *
+ * @param cls the NeighbourConnectCtxt created in GST_handle_link_controllers()
+ * @param tc the scheduler task context
+ */
+static void
+timeout_neighbour_connect (void *cls,
+                           const struct GNUNET_SCHEDULER_TaskContext *tc)
+{
+ struct NeighbourConnectCtxt *ncc = cls;
+
+ ncc->timeout_task = GNUNET_SCHEDULER_NO_TASK;
+ send_controller_link_response (ncc->client, ncc->op_id, NULL,
+                                "Could not connect to delegated controller");
+ cleanup_ncc (ncc);
+}
+
+
+/**
+ * Callback called when a connection to the neighbour is made
+ *
+ * @param cls the NeighbourConnectCtxt created in GST_handle_link_controllers()
+ * @param c the handle the neighbour's controller
+ */
+static void
+neighbour_connect_cb (void *cls, struct GNUNET_TESTBED_Controller *c)
+{
+  struct NeighbourConnectCtxt *ncc = cls;
+
+  GNUNET_SCHEDULER_cancel (ncc->timeout_task);
+  ncc->timeout_task = GNUNET_SCHEDULER_NO_TASK;
+  ncc->nh = NULL;
+  GST_neighbour_release_connection (ncc->n);
+  send_controller_link_response (ncc->client, ncc->op_id, NULL, NULL);
+  cleanup_ncc (ncc);
+}
+
+
+/**
+ * Function to create a neigbour and add it into the neighbour list
+ *
+ * @param host the host of the neighbour
+ */
+struct Neighbour *
+GST_create_neighbour (struct GNUNET_TESTBED_Host *host)
+{
+  struct Neighbour *n;
+
+  n = GNUNET_malloc (sizeof (struct Neighbour));
+  n->host_id = GNUNET_TESTBED_host_get_id_ (host);
+  neighbour_list_add (n);   /* just add; connect on-demand */
+  return n;
+}
+
+
 /**
  * Message handler for GNUNET_MESSAGE_TYPE_TESTBED_LCONTROLLERS message
  *
@@ -562,16 +1179,15 @@ clean_lcc:
  */
 void
 GST_handle_link_controllers (void *cls, struct GNUNET_SERVER_Client *client,
-                         const struct GNUNET_MessageHeader *message)
+                             const struct GNUNET_MessageHeader *message)
 {
   const struct GNUNET_TESTBED_ControllerLinkRequest *msg;
-  struct GNUNET_CONFIGURATION_Handle *cfg;
   struct LCFContextQueue *lcfq;
   struct Route *route;
   struct Route *new_route;
+  uint64_t op_id;
   uint32_t delegated_host_id;
   uint32_t slave_host_id;
-  uint16_t msize;
 
   if (NULL == GST_context)
   {
@@ -579,13 +1195,6 @@ GST_handle_link_controllers (void *cls, struct GNUNET_SERVER_Client *client,
     GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
     return;
   }
-  msize = ntohs (message->size);
-  if (sizeof (struct GNUNET_TESTBED_ControllerLinkRequest) >= msize)
-  {
-    GNUNET_break (0);
-    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
-    return;
-  }
   msg = (const struct GNUNET_TESTBED_ControllerLinkRequest *) message;
   delegated_host_id = ntohl (msg->delegated_host_id);
   if (delegated_host_id == GST_context->host_id)
@@ -618,18 +1227,41 @@ GST_handle_link_controllers (void *cls, struct GNUNET_SERVER_Client *client,
     GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
     return;
   }
-  cfg = GNUNET_TESTBED_extract_config_ (message); /* destroy cfg here or in lcfcontext */
-  if (NULL == cfg)
-  {
-    GNUNET_break (0);         /* Configuration parsing error */
-    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
-    return;
-  }
+  op_id = GNUNET_ntohll (msg->operation_id);
   if (slave_host_id == GST_context->host_id)    /* Link from us */
   {
     struct Slave *slave;
     struct LinkControllersContext *lcc;
 
+
+    if (1 != msg->is_subordinate)
+    {
+      struct Neighbour *n;
+      struct NeighbourConnectCtxt *ncc;
+
+      if ((delegated_host_id < neighbour_list_size) &&
+        (NULL != neighbour_list[delegated_host_id]))
+      {
+        GNUNET_break (0);
+        GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
+        return;
+      }
+      LOG_DEBUG ("Received request to establish a link to host %u\n",
+                 delegated_host_id);
+      n = GST_create_neighbour (GST_host_list[delegated_host_id]);
+      ncc = GNUNET_malloc (sizeof (struct NeighbourConnectCtxt));
+      ncc->n = n;
+      ncc->op_id = op_id;
+      ncc->client = client;
+      GNUNET_SERVER_client_keep (client);
+      ncc->nh = GST_neighbour_get_connection (n, neighbour_connect_cb, ncc);
+      ncc->timeout_task = GNUNET_SCHEDULER_add_delayed (GST_timeout,
+                                                        &timeout_neighbour_connect,
+                                                        ncc);
+      GNUNET_CONTAINER_DLL_insert_tail (ncc_head, ncc_tail, ncc);
+      GNUNET_SERVER_receive_done (client, GNUNET_OK);
+      return;
+    }
     if ((delegated_host_id < GST_slave_list_size) &&
         (NULL != GST_slave_list[delegated_host_id]))
     {
@@ -637,39 +1269,21 @@ GST_handle_link_controllers (void *cls, struct GNUNET_SERVER_Client *client,
       GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
       return;
     }
+    LOG_DEBUG ("Received request to start and establish a link to host %u\n",
+               delegated_host_id);
     slave = GNUNET_malloc (sizeof (struct Slave));
     slave->host_id = delegated_host_id;
     slave->reghost_map = GNUNET_CONTAINER_multihashmap_create (100, GNUNET_NO);
     slave_list_add (slave);
-    if (1 != msg->is_subordinate)
-    {
-      slave->controller =
-          GNUNET_TESTBED_controller_connect (cfg, GST_host_list[slave->host_id],
-                                             EVENT_MASK, &slave_event_callback,
-                                             slave);
-      if (NULL != slave->controller)
-        send_controller_link_response (client,
-                                       GNUNET_ntohll (msg->operation_id),
-                                       NULL,
-                                       NULL);
-      else
-        send_controller_link_response (client,
-                                       GNUNET_ntohll (msg->operation_id),
-                                       NULL,
-                                       "Could not connect to delegated controller");
-      GNUNET_SERVER_receive_done (client, GNUNET_OK);
-      return;
-    }
     lcc = GNUNET_malloc (sizeof (struct LinkControllersContext));
-    lcc->operation_id = GNUNET_ntohll (msg->operation_id);
+    lcc->operation_id = op_id;
     GNUNET_SERVER_client_keep (client);
     lcc->client = client;
     slave->lcc = lcc;
     slave->controller_proc =
         GNUNET_TESTBED_controller_start (GST_context->master_ip,
-                                         GST_host_list[slave->host_id], cfg,
-                                         &slave_status_callback, slave);
-    GNUNET_CONFIGURATION_destroy (cfg);
+                                         GST_host_list[slave->host_id],
+                                         &slave_status_cb, slave);
     new_route = GNUNET_malloc (sizeof (struct Route));
     new_route->dest = delegated_host_id;
     new_route->thru = GST_context->host_id;
@@ -686,17 +1300,15 @@ GST_handle_link_controllers (void *cls, struct GNUNET_SERVER_Client *client,
   }
   lcfq = GNUNET_malloc (sizeof (struct LCFContextQueue));
   lcfq->lcf = GNUNET_malloc (sizeof (struct LCFContext));
-  lcfq->lcf->type = CLOSURE_TYPE_LCF;
   lcfq->lcf->delegated_host_id = delegated_host_id;
   lcfq->lcf->slave_host_id = slave_host_id;
   route = GST_find_dest_route (slave_host_id);
   GNUNET_assert (NULL != route);        /* because we add routes carefully */
   GNUNET_assert (route->dest < GST_slave_list_size);
   GNUNET_assert (NULL != GST_slave_list[route->dest]);
-  lcfq->lcf->cfg = cfg;
   lcfq->lcf->is_subordinate = msg->is_subordinate;
   lcfq->lcf->state = INIT;
-  lcfq->lcf->operation_id = GNUNET_ntohll (msg->operation_id);
+  lcfq->lcf->operation_id = op_id;
   lcfq->lcf->gateway = GST_slave_list[route->dest];
   GNUNET_SERVER_client_keep (client);
   lcfq->lcf->client = client;
@@ -738,7 +1350,8 @@ void
 GST_free_lcfq ()
 {
   struct LCFContextQueue *lcfq;
-  
+  struct LCFContext *lcf;
+
   if (NULL != lcfq_head)
   {
     if (GNUNET_SCHEDULER_NO_TASK != lcf_proc_task_id)
@@ -750,10 +1363,13 @@ GST_free_lcfq ()
   GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == lcf_proc_task_id);
   for (lcfq = lcfq_head; NULL != lcfq; lcfq = lcfq_head)
   {
-    GNUNET_SERVER_client_drop (lcfq->lcf->client);
-    GNUNET_assert (NULL != lcfq->lcf->cfg);
-    GNUNET_CONFIGURATION_destroy (lcfq->lcf->cfg);
-    GNUNET_free (lcfq->lcf);
+    lcf = lcfq->lcf;
+    GNUNET_SERVER_client_drop (lcf->client);
+    if (NULL != lcf->op)
+      GNUNET_TESTBED_operation_done (lcf->op);
+    if (GNUNET_SCHEDULER_NO_TASK != lcf->timeout_task)
+      GNUNET_SCHEDULER_cancel (lcf->timeout_task);
+    GNUNET_free (lcf);
     GNUNET_CONTAINER_DLL_remove (lcfq_head, lcfq_tail, lcfq);
     GNUNET_free (lcfq);
   }