-bringing copyright tags up to FSF standard
[oweals/gnunet.git] / src / transport / transport_api.c
index c6ee3e47da3e65496ba6b1a0bc38fa286b1d611e..2da1a90d62896c17046545c742532d5a1981eddd 100644 (file)
@@ -1,6 +1,6 @@
 /*
      This file is part of GNUnet.
-     (C) 2009-2013 Christian Grothoff (and other contributing authors)
+     Copyright (C) 2009-2013 Christian Grothoff (and other contributing authors)
 
      GNUnet is free software; you can redistribute it and/or modify
      it under the terms of the GNU General Public License as published
@@ -65,13 +65,13 @@ struct GNUNET_TRANSPORT_TransmitHandle
   struct Neighbour *neighbour;
 
   /**
-   * Function to call when notify_size bytes are available
+   * Function to call when @e notify_size bytes are available
    * for transmission.
    */
   GNUNET_TRANSPORT_TransmitReadyNotify notify;
 
   /**
-   * Closure for notify.
+   * Closure for @e notify.
    */
   void *notify_cls;
 
@@ -84,7 +84,7 @@ struct GNUNET_TRANSPORT_TransmitHandle
    * Task to trigger request timeout if the request is stalled due to
    * congestion.
    */
-  GNUNET_SCHEDULER_TaskIdentifier timeout_task;
+  struct GNUNET_SCHEDULER_Task * timeout_task;
 
   /**
    * How many bytes is our notify callback waiting for?
@@ -95,7 +95,7 @@ struct GNUNET_TRANSPORT_TransmitHandle
 
 
 /**
- * Entry in hash table of all of our current neighbours.
+ * Entry in hash table of all of our current (connected) neighbours.
  */
 struct Neighbour
 {
@@ -120,11 +120,11 @@ struct Neighbour
   struct GNUNET_BANDWIDTH_Tracker out_tracker;
 
   /**
-   * Entry in our readyness heap (which is sorted by 'next_ready'
+   * Entry in our readyness heap (which is sorted by @e next_ready
    * value).  NULL if there is no pending transmission request for
-   * this neighbour or if we're waiting for 'is_ready' to become
-   * true AFTER the 'out_tracker' suggested that this peer's quota
-   * has been satisfied (so once 'is_ready' goes to GNUNET_YES,
+   * this neighbour or if we're waiting for @e is_ready to become
+   * true AFTER the @e out_tracker suggested that this peer's quota
+   * has been satisfied (so once @e is_ready goes to #GNUNET_YES,
    * we should immediately go back into the heap).
    */
   struct GNUNET_CONTAINER_HeapNode *hn;
@@ -171,7 +171,7 @@ struct GNUNET_TRANSPORT_GetHelloHandle
   /**
    * Task for calling the HelloUpdateCallback when we already have a HELLO
    */
-  GNUNET_SCHEDULER_TaskIdentifier notify_task;
+  struct GNUNET_SCHEDULER_Task * notify_task;
 
   /**
    * Closure for @e rec.
@@ -180,8 +180,9 @@ struct GNUNET_TRANSPORT_GetHelloHandle
 
 };
 
+
 /**
- * Linked list for all try-connect requests
+ * Entry in linked list for a try-connect request.
  */
 struct GNUNET_TRANSPORT_TryConnectHandle
 {
@@ -195,23 +196,79 @@ struct GNUNET_TRANSPORT_TryConnectHandle
    */
   struct GNUNET_TRANSPORT_TryConnectHandle *next;
 
+  /**
+   * Peer we should try to connect to.
+   */
   struct GNUNET_PeerIdentity pid;
 
+  /**
+   * Transport service handle this request is part of.
+   */
   struct GNUNET_TRANSPORT_Handle *th;
 
+  /**
+   * Message transmission request to communicate to service.
+   */
   struct GNUNET_TRANSPORT_TransmitHandle *tth;
 
+  /**
+   * Function to call upon completion (of request transmission).
+   */
   GNUNET_TRANSPORT_TryConnectCallback cb;
 
   /**
    * Closure for @e cb.
    */
   void *cb_cls;
+
 };
 
 
 /**
- * Linked list for all try-connect requests
+ * Entry in linked list for all try-disconnect requests
+ */
+struct GNUNET_TRANSPORT_TryDisconnectHandle
+{
+  /**
+   * For the DLL.
+   */
+  struct GNUNET_TRANSPORT_TryDisconnectHandle *prev;
+
+  /**
+   * For the DLL.
+   */
+  struct GNUNET_TRANSPORT_TryDisconnectHandle *next;
+
+  /**
+   * Peer we should try to connect to.
+   */
+  struct GNUNET_PeerIdentity pid;
+
+  /**
+   * Transport service handle this request is part of.
+   */
+  struct GNUNET_TRANSPORT_Handle *th;
+
+  /**
+   * Message transmission request to communicate to service.
+   */
+  struct GNUNET_TRANSPORT_TransmitHandle *tth;
+
+  /**
+   * Function to call upon completion (of request transmission).
+   */
+  GNUNET_TRANSPORT_TryDisconnectCallback cb;
+
+  /**
+   * Closure for @e cb.
+   */
+  void *cb_cls;
+
+};
+
+
+/**
+ * Entry in linked list for all offer-HELLO requests.
  */
 struct GNUNET_TRANSPORT_OfferHelloHandle
 {
@@ -225,17 +282,29 @@ struct GNUNET_TRANSPORT_OfferHelloHandle
    */
   struct GNUNET_TRANSPORT_OfferHelloHandle *next;
 
+  /**
+   * Transport service handle we use for transmission.
+   */
   struct GNUNET_TRANSPORT_Handle *th;
 
+  /**
+   * Transmission handle for this request.
+   */
   struct GNUNET_TRANSPORT_TransmitHandle *tth;
 
-  GNUNET_SCHEDULER_Task cont;
+  /**
+   * Function to call once we are done.
+   */
+  GNUNET_SCHEDULER_TaskCallback cont;
 
   /**
    * Closure for @e cont
    */
   void *cls;
 
+  /**
+   * The HELLO message to be transmitted.
+   */
   struct GNUNET_MessageHeader *msg;
 };
 
@@ -318,6 +387,16 @@ struct GNUNET_TRANSPORT_Handle
    */
   struct GNUNET_TRANSPORT_TryConnectHandle *tc_tail;
 
+  /**
+   * Linked list of pending try disconnect requests head
+   */
+  struct GNUNET_TRANSPORT_TryDisconnectHandle *td_head;
+
+  /**
+   * Linked list of pending try connect requests tail
+   */
+  struct GNUNET_TRANSPORT_TryDisconnectHandle *td_tail;
+
   /**
    * Linked list of pending offer HELLO requests head
    */
@@ -355,7 +434,7 @@ struct GNUNET_TRANSPORT_Handle
   /**
    * ID of the task trying to reconnect to the service.
    */
-  GNUNET_SCHEDULER_TaskIdentifier reconnect_task;
+  struct GNUNET_SCHEDULER_Task * reconnect_task;
 
   /**
    * ID of the task trying to trigger transmission for a peer while
@@ -363,7 +442,7 @@ struct GNUNET_TRANSPORT_Handle
    * messages and the smallest entry in the 'ready_heap' has a time
    * stamp in the future.
    */
-  GNUNET_SCHEDULER_TaskIdentifier quota_task;
+  struct GNUNET_SCHEDULER_Task * quota_task;
 
   /**
    * Delay until we try to reconnect.
@@ -383,7 +462,6 @@ struct GNUNET_TRANSPORT_Handle
 };
 
 
-
 /**
  * Schedule the task to send one message, either from the control
  * list or the peer message queues  to the service.
@@ -434,7 +512,7 @@ outbound_bw_tracker_update (void *cls)
   if (NULL == n->hn)
     return;
   delay = GNUNET_BANDWIDTH_tracker_get_delay (&n->out_tracker,
-      n->th->notify_size + n->traffic_overhead);
+                                              n->th->notify_size + n->traffic_overhead);
   LOG (GNUNET_ERROR_TYPE_DEBUG,
        "New outbound delay %llu us\n",
        GNUNET_STRINGS_relative_time_to_string (delay,
@@ -533,7 +611,8 @@ neighbour_delete (void *cls,
  * @param msg message received, NULL on timeout or fatal error
  */
 static void
-demultiplexer (void *cls, const struct GNUNET_MessageHeader *msg)
+demultiplexer (void *cls,
+               const struct GNUNET_MessageHeader *msg)
 {
   struct GNUNET_TRANSPORT_Handle *h = cls;
   const struct DisconnectInfoMessage *dim;
@@ -624,7 +703,8 @@ demultiplexer (void *cls, const struct GNUNET_MessageHeader *msg)
          "CONNECT",
          GNUNET_i2s (&cim->id),
          ntohl (cim->quota_out.value__));
-    GNUNET_BANDWIDTH_tracker_update_quota (&n->out_tracker, cim->quota_out);
+    GNUNET_BANDWIDTH_tracker_update_quota (&n->out_tracker,
+                                           cim->quota_out);
     if (h->nc_cb != NULL)
       h->nc_cb (h->cls, &n->id);
     break;
@@ -666,18 +746,19 @@ demultiplexer (void *cls, const struct GNUNET_MessageHeader *msg)
 
     if (bytes_physical >= bytes_msg)
     {
-        LOG (GNUNET_ERROR_TYPE_DEBUG,
-             "Overhead for %u byte message: %u\n",
-            bytes_msg, bytes_physical - bytes_msg);
+      LOG (GNUNET_ERROR_TYPE_DEBUG,
+           "Overhead for %u byte message: %u\n",
+           bytes_msg,
+           bytes_physical - bytes_msg);
       n->traffic_overhead += bytes_physical - bytes_msg;
     }
     GNUNET_break (GNUNET_NO == n->is_ready);
     n->is_ready = GNUNET_YES;
     if ((NULL != n->th) && (NULL == n->hn))
     {
-      GNUNET_assert (GNUNET_SCHEDULER_NO_TASK != n->th->timeout_task);
+      GNUNET_assert (NULL != n->th->timeout_task);
       GNUNET_SCHEDULER_cancel (n->th->timeout_task);
-      n->th->timeout_task = GNUNET_SCHEDULER_NO_TASK;
+      n->th->timeout_task = NULL;
       /* we've been waiting for this (congestion, not quota,
        * caused delayed transmission) */
       n->hn = GNUNET_CONTAINER_heap_insert (h->ready_heap, n, 0);
@@ -756,7 +837,7 @@ timeout_request_due_to_congestion (void *cls,
   struct GNUNET_TRANSPORT_TransmitHandle *th = cls;
   struct Neighbour *n = th->neighbour;
 
-  n->th->timeout_task = GNUNET_SCHEDULER_NO_TASK;
+  n->th->timeout_task = NULL;
   GNUNET_assert (th == n->th);
   GNUNET_assert (NULL == n->hn);
   n->th = NULL;
@@ -818,7 +899,7 @@ transport_notify_ready (void *cls, size_t size, void *buf)
       /* peer not ready, wait for notification! */
       GNUNET_assert (n == GNUNET_CONTAINER_heap_remove_root (h->ready_heap));
       n->hn = NULL;
-      GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == n->th->timeout_task);
+      GNUNET_assert (NULL == n->th->timeout_task);
       n->th->timeout_task =
           GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_absolute_get_remaining
                                         (n->th->timeout),
@@ -884,7 +965,7 @@ schedule_transmission_task (void *cls,
   struct GNUNET_TRANSPORT_TransmitHandle *th;
   struct Neighbour *n;
 
-  h->quota_task = GNUNET_SCHEDULER_NO_TASK;
+  h->quota_task = NULL;
   GNUNET_assert (NULL != h->client);
   /* destroy all requests that have timed out */
   while ((NULL != (n = GNUNET_CONTAINER_heap_peek (h->ready_heap))) &&
@@ -939,10 +1020,10 @@ schedule_transmission (struct GNUNET_TRANSPORT_Handle *h)
   struct Neighbour *n;
 
   GNUNET_assert (NULL != h->client);
-  if (h->quota_task != GNUNET_SCHEDULER_NO_TASK)
+  if (h->quota_task != NULL)
   {
     GNUNET_SCHEDULER_cancel (h->quota_task);
-    h->quota_task = GNUNET_SCHEDULER_NO_TASK;
+    h->quota_task = NULL;
   }
   if (NULL != h->control_head)
     delay = GNUNET_TIME_UNIT_ZERO;
@@ -1048,7 +1129,7 @@ reconnect (void *cls,
 {
   struct GNUNET_TRANSPORT_Handle *h = cls;
 
-  h->reconnect_task = GNUNET_SCHEDULER_NO_TASK;
+  h->reconnect_task = NULL;
   if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
   {
     /* shutdown, just give up */
@@ -1079,7 +1160,7 @@ disconnect_and_schedule_reconnect (struct GNUNET_TRANSPORT_Handle *h)
 {
   struct GNUNET_TRANSPORT_TransmitHandle *th;
 
-  GNUNET_assert (h->reconnect_task == GNUNET_SCHEDULER_NO_TASK);
+  GNUNET_assert (h->reconnect_task == NULL);
   if (NULL != h->cth)
   {
     GNUNET_CLIENT_notify_transmit_ready_cancel (h->cth);
@@ -1095,10 +1176,10 @@ disconnect_and_schedule_reconnect (struct GNUNET_TRANSPORT_Handle *h)
   /* Forget about all neighbours that we used to be connected to */
   GNUNET_CONTAINER_multipeermap_iterate (h->neighbours,
                                          &neighbour_delete, h);
-  if (h->quota_task != GNUNET_SCHEDULER_NO_TASK)
+  if (h->quota_task != NULL)
   {
     GNUNET_SCHEDULER_cancel (h->quota_task);
-    h->quota_task = GNUNET_SCHEDULER_NO_TASK;
+    h->quota_task = NULL;
   }
   while ((NULL != (th = h->control_head)))
   {
@@ -1132,31 +1213,34 @@ cancel_control_transmit (struct GNUNET_TRANSPORT_Handle *th,
 }
 
 
-
 /**
- * Send REQUEST_CONNECT message to the service.
+ * Send #GNUNET_MESSAGE_TYPE_TRANSPORT_REQUEST_CONNECT message to the
+ * service.
  *
- * @param cls the `struct GNUNET_PeerIdentity`
+ * @param cls the `struct GNUNET_TRANSPORT_TryConnectHandle`
  * @param size number of bytes available in @a buf
  * @param buf where to copy the message
  * @return number of bytes copied to @a buf
  */
 static size_t
-send_try_connect (void *cls, size_t size, void *buf)
+send_try_connect (void *cls,
+                  size_t size,
+                  void *buf)
 {
   struct GNUNET_TRANSPORT_TryConnectHandle *tch = cls;
   struct TransportRequestConnectMessage msg;
 
+  tch->tth = NULL;
   if (NULL == buf)
   {
-    if (NULL != tch->cb)
-      tch->cb (tch->cb_cls, GNUNET_SYSERR);
-    GNUNET_CONTAINER_DLL_remove (tch->th->tc_head, tch->th->tc_tail, tch);
     LOG (GNUNET_ERROR_TYPE_DEBUG,
          "Discarding  `%s' request to `%4s' due to error in transport service connection.\n",
          "REQUEST_CONNECT",
          GNUNET_i2s (&tch->pid));
-    GNUNET_free (tch);
+    if (NULL != tch->cb)
+      tch->cb (tch->cb_cls,
+               GNUNET_SYSERR);
+    GNUNET_TRANSPORT_try_connect_cancel (tch);
     return 0;
   }
   LOG (GNUNET_ERROR_TYPE_DEBUG,
@@ -1171,11 +1255,11 @@ send_try_connect (void *cls, size_t size, void *buf)
   memcpy (buf, &msg, sizeof (msg));
   if (NULL != tch->cb)
     tch->cb (tch->cb_cls, GNUNET_OK);
-  GNUNET_CONTAINER_DLL_remove (tch->th->tc_head, tch->th->tc_tail, tch);
-  GNUNET_free (tch);
+  GNUNET_TRANSPORT_try_connect_cancel (tch);
   return sizeof (struct TransportRequestConnectMessage);
 }
 
+
 /**
  * Ask the transport service to establish a connection to
  * the given peer.
@@ -1194,19 +1278,21 @@ GNUNET_TRANSPORT_try_connect (struct GNUNET_TRANSPORT_Handle *handle,
                               GNUNET_TRANSPORT_TryConnectCallback cb,
                               void *cb_cls)
 {
-  struct GNUNET_TRANSPORT_TryConnectHandle *tch = NULL;
+  struct GNUNET_TRANSPORT_TryConnectHandle *tch;
 
   if (NULL == handle->client)
-      return NULL;
+    return NULL;
   tch = GNUNET_new (struct GNUNET_TRANSPORT_TryConnectHandle);
   tch->th = handle;
-  tch->pid = *(target);
+  tch->pid = *target;
   tch->cb = cb;
   tch->cb_cls = cb_cls;
   tch->tth = schedule_control_transmit (handle,
                                         sizeof (struct TransportRequestConnectMessage),
                                         &send_try_connect, tch);
-  GNUNET_CONTAINER_DLL_insert(handle->tc_head, handle->tc_tail, tch);
+  GNUNET_CONTAINER_DLL_insert (handle->tc_head,
+                               handle->tc_tail,
+                               tch);
   return tch;
 }
 
@@ -1223,12 +1309,120 @@ GNUNET_TRANSPORT_try_connect_cancel (struct GNUNET_TRANSPORT_TryConnectHandle *t
   struct GNUNET_TRANSPORT_Handle *th;
 
   th = tch->th;
-  cancel_control_transmit (th, tch->tth);
-  GNUNET_CONTAINER_DLL_remove (th->tc_head, th->tc_tail, tch);
+  if (NULL != tch->tth)
+    cancel_control_transmit (th, tch->tth);
+  GNUNET_CONTAINER_DLL_remove (th->tc_head,
+                               th->tc_tail,
+                               tch);
   GNUNET_free (tch);
 }
 
 
+/**
+ * Send #GNUNET_MESSAGE_TYPE_TRANSPORT_REQUEST_DISCONNECT message to the
+ * service.
+ *
+ * @param cls the `struct GNUNET_TRANSPORT_TryDisconnectHandle`
+ * @param size number of bytes available in @a buf
+ * @param buf where to copy the message
+ * @return number of bytes copied to @a buf
+ */
+static size_t
+send_try_disconnect (void *cls,
+                     size_t size,
+                     void *buf)
+{
+  struct GNUNET_TRANSPORT_TryDisconnectHandle *tdh = cls;
+  struct TransportRequestConnectMessage msg;
+
+  tdh->th = NULL;
+  if (NULL == buf)
+  {
+    LOG (GNUNET_ERROR_TYPE_DEBUG,
+         "Discarding  `%s' request to `%4s' due to error in transport service connection.\n",
+         "REQUEST_DISCONNECT",
+         GNUNET_i2s (&tdh->pid));
+    if (NULL != tdh->cb)
+      tdh->cb (tdh->cb_cls,
+               GNUNET_SYSERR);
+    GNUNET_TRANSPORT_try_disconnect_cancel (tdh);
+    return 0;
+  }
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Transmitting `%s' request with respect to `%4s'.\n",
+       "REQUEST_DISCONNECT",
+       GNUNET_i2s (&tdh->pid));
+  GNUNET_assert (size >= sizeof (struct TransportRequestDisconnectMessage));
+  msg.header.size = htons (sizeof (struct TransportRequestDisconnectMessage));
+  msg.header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_REQUEST_DISCONNECT);
+  msg.reserved = htonl (0);
+  msg.peer = tdh->pid;
+  memcpy (buf, &msg, sizeof (msg));
+  if (NULL != tdh->cb)
+    tdh->cb (tdh->cb_cls, GNUNET_OK);
+  GNUNET_TRANSPORT_try_disconnect_cancel (tdh);
+  return sizeof (struct TransportRequestDisconnectMessage);
+}
+
+
+/**
+ * Ask the transport service to shutdown a connection to
+ * the given peer.
+ *
+ * @param handle connection to transport service
+ * @param target who we should try to connect to
+ * @param cb callback to be called when request was transmitted to transport
+ *         service
+ * @param cb_cls closure for the callback @a cb
+ * @return a `struct GNUNET_TRANSPORT_TryDisconnectHandle` handle or
+ *         NULL on failure (cb will not be called)
+ */
+struct GNUNET_TRANSPORT_TryDisconnectHandle *
+GNUNET_TRANSPORT_try_disconnect (struct GNUNET_TRANSPORT_Handle *handle,
+                                 const struct GNUNET_PeerIdentity *target,
+                                 GNUNET_TRANSPORT_TryDisconnectCallback cb,
+                                 void *cb_cls)
+{
+  struct GNUNET_TRANSPORT_TryDisconnectHandle *tdh;
+
+  if (NULL == handle->client)
+    return NULL;
+  tdh = GNUNET_new (struct GNUNET_TRANSPORT_TryDisconnectHandle);
+  tdh->th = handle;
+  tdh->pid = *target;
+  tdh->cb = cb;
+  tdh->cb_cls = cb_cls;
+  tdh->tth = schedule_control_transmit (handle,
+                                        sizeof (struct TransportRequestDisconnectMessage),
+                                        &send_try_disconnect, tdh);
+  GNUNET_CONTAINER_DLL_insert (handle->td_head,
+                               handle->td_tail,
+                               tdh);
+  return tdh;
+}
+
+
+/**
+ * Cancel the request to transport to try a disconnect
+ * Callback will not be called
+ *
+ * @param tdh the handle to cancel
+ */
+void
+GNUNET_TRANSPORT_try_disconnect_cancel (struct GNUNET_TRANSPORT_TryDisconnectHandle *tdh)
+{
+  struct GNUNET_TRANSPORT_Handle *th;
+
+  th = tdh->th;
+  if (NULL != tdh->tth)
+    cancel_control_transmit (th, tdh->tth);
+  GNUNET_CONTAINER_DLL_remove (th->td_head,
+                               th->td_tail,
+                               tdh);
+  GNUNET_free (tdh);
+}
+
+
 /**
  * Send HELLO message to the service.
  *
@@ -1385,7 +1579,7 @@ GNUNET_TRANSPORT_set_traffic_metric (struct GNUNET_TRANSPORT_Handle *handle,
 struct GNUNET_TRANSPORT_OfferHelloHandle *
 GNUNET_TRANSPORT_offer_hello (struct GNUNET_TRANSPORT_Handle *handle,
                               const struct GNUNET_MessageHeader *hello,
-                              GNUNET_SCHEDULER_Task cont, void *cls)
+                              GNUNET_SCHEDULER_TaskCallback cont, void *cls)
 {
   struct GNUNET_TRANSPORT_OfferHelloHandle *ohh;
   struct GNUNET_MessageHeader *msg;
@@ -1471,8 +1665,8 @@ call_hello_update_cb_async (void *cls,
   struct GNUNET_TRANSPORT_GetHelloHandle *ghh = cls;
 
   GNUNET_assert (NULL != ghh->handle->my_hello);
-  GNUNET_assert (GNUNET_SCHEDULER_NO_TASK != ghh->notify_task);
-  ghh->notify_task = GNUNET_SCHEDULER_NO_TASK;
+  GNUNET_assert (NULL != ghh->notify_task);
+  ghh->notify_task = NULL;
   ghh->rec (ghh->rec_cls,
             (const struct GNUNET_MessageHeader *) ghh->handle->my_hello);
 }
@@ -1519,7 +1713,7 @@ GNUNET_TRANSPORT_get_hello_cancel (struct GNUNET_TRANSPORT_GetHelloHandle *ghh)
 {
   struct GNUNET_TRANSPORT_Handle *handle = ghh->handle;
 
-  if (GNUNET_SCHEDULER_NO_TASK != ghh->notify_task)
+  if (NULL != ghh->notify_task)
     GNUNET_SCHEDULER_cancel (ghh->notify_task);
   GNUNET_CONTAINER_DLL_remove (handle->hwl_head, handle->hwl_tail, ghh);
   GNUNET_free (ghh);
@@ -1618,20 +1812,20 @@ GNUNET_TRANSPORT_disconnect (struct GNUNET_TRANSPORT_Handle *handle)
   LOG (GNUNET_ERROR_TYPE_DEBUG,
        "Transport disconnect called!\n");
   /* this disconnects all neighbours... */
-  if (handle->reconnect_task == GNUNET_SCHEDULER_NO_TASK)
+  if (handle->reconnect_task == NULL)
     disconnect_and_schedule_reconnect (handle);
   /* and now we stop trying to connect again... */
-  if (handle->reconnect_task != GNUNET_SCHEDULER_NO_TASK)
+  if (handle->reconnect_task != NULL)
   {
     GNUNET_SCHEDULER_cancel (handle->reconnect_task);
-    handle->reconnect_task = GNUNET_SCHEDULER_NO_TASK;
+    handle->reconnect_task = NULL;
   }
   GNUNET_CONTAINER_multipeermap_destroy (handle->neighbours);
   handle->neighbours = NULL;
-  if (handle->quota_task != GNUNET_SCHEDULER_NO_TASK)
+  if (handle->quota_task != NULL)
   {
     GNUNET_SCHEDULER_cancel (handle->quota_task);
-    handle->quota_task = GNUNET_SCHEDULER_NO_TASK;
+    handle->quota_task = NULL;
   }
   GNUNET_free_non_null (handle->my_hello);
   handle->my_hello = NULL;
@@ -1734,9 +1928,9 @@ GNUNET_TRANSPORT_notify_transmit_ready_cancel (struct GNUNET_TRANSPORT_TransmitH
   }
   else
   {
-    GNUNET_assert (GNUNET_SCHEDULER_NO_TASK != th->timeout_task);
+    GNUNET_assert (NULL != th->timeout_task);
     GNUNET_SCHEDULER_cancel (th->timeout_task);
-    th->timeout_task = GNUNET_SCHEDULER_NO_TASK;
+    th->timeout_task = NULL;
   }
   GNUNET_free (th);
 }