-fix NPE
[oweals/gnunet.git] / src / transport / gnunet-service-transport_clients.c
index f3050b6e9b49ba0719f8661da5dae869861c01cd..8c1ca61e5bfa6754089f39899489278d9f932964 100644 (file)
@@ -1,6 +1,6 @@
 /*
      This file is part of GNUnet.
-     (C) 2010-2013 Christian Grothoff (and other contributing authors)
+     Copyright (C) 2010-2015 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
 
      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 transport/gnunet-service-transport_clients.c
- * @brief plugin management API
+ * @brief communication with clients (core service and monitors)
  * @author Christian Grothoff
  */
 #include "platform.h"
@@ -117,6 +117,7 @@ struct TransportClient
   int send_payload;
 };
 
+
 /**
  * Context for address to string operations
  */
@@ -138,8 +139,11 @@ struct AddressToStringContext
   struct GNUNET_SERVER_TransmitContext* tc;
 };
 
+
 /**
- * Client monitoring changes of active addresses of our neighbours.
+ * Client monitoring changes of active addresses or validations
+ * of our neighbours. Which type is being monitored depends on the
+ * DLL this struct is in.
  */
 struct MonitoringClient
 {
@@ -180,12 +184,12 @@ static struct TransportClient *clients_tail;
 /**
  * Head of linked list of all pending address iterations
  */
-struct AddressToStringContext *a2s_head;
+static struct AddressToStringContext *a2s_head;
 
 /**
  * Tail of linked list of all pending address iterations
  */
-struct AddressToStringContext *a2s_tail;
+static struct AddressToStringContext *a2s_tail;
 
 /**
  * Head of linked list of monitoring clients.
@@ -220,7 +224,26 @@ static struct GNUNET_SERVER_NotificationContext *peer_nc;
 static struct GNUNET_SERVER_NotificationContext *val_nc;
 
 /**
- * Find the internal handle associated with the given client handle
+ * Notification context, to send updates on changes to active plugin
+ * connections.
+ */
+static struct GNUNET_SERVER_NotificationContext *plugin_nc;
+
+/**
+ * Plugin monitoring client we are currently syncing, NULL if all
+ * monitoring clients are in sync.
+ */
+static struct GNUNET_SERVER_Client *sync_client;
+
+/**
+ * Peer identity that is all zeros, used as a way to indicate
+ * "all peers".  Used for comparissons.
+ */
+static struct GNUNET_PeerIdentity all_zeros;
+
+
+/**
+ * Find the internal handle associated with the given client handle.
  *
  * @param client server's client handle to look up
  * @return internal client handle
@@ -228,17 +251,13 @@ static struct GNUNET_SERVER_NotificationContext *val_nc;
 static struct TransportClient *
 lookup_client (struct GNUNET_SERVER_Client *client)
 {
-  struct TransportClient *tc;
-
-  for (tc = clients_head; NULL != tc; tc = tc->next)
-    if (tc->client == client)
-      return tc;
-  return NULL;
+  return GNUNET_SERVER_client_get_user_context (client,
+                                                struct TransportClient);
 }
 
 
 /**
- * Create the internal handle for the given server client handle
+ * Create the internal handle for the given server client handle.
  *
  * @param client server's client handle to create our internal handle for
  * @return fresh internal client handle
@@ -251,6 +270,10 @@ setup_client (struct GNUNET_SERVER_Client *client)
   GNUNET_assert (NULL == lookup_client (client));
   tc = GNUNET_new (struct TransportClient);
   tc->client = client;
+  GNUNET_SERVER_client_set_user_context (client, tc);
+  GNUNET_CONTAINER_DLL_insert (clients_head,
+                               clients_tail,
+                               tc);
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
               "Client %p connected\n",
               tc);
@@ -260,7 +283,7 @@ setup_client (struct GNUNET_SERVER_Client *client)
 
 /**
  * Find the handle to the monitoring client associated with the given
- * client handle
+ * client handle.
  *
  * @param head the head of the client queue to look in
  * @param client server's client handle to look up
@@ -268,7 +291,7 @@ setup_client (struct GNUNET_SERVER_Client *client)
  */
 static struct MonitoringClient *
 lookup_monitoring_client (struct MonitoringClient *head,
-    struct GNUNET_SERVER_Client *client)
+                          struct GNUNET_SERVER_Client *client)
 {
   struct MonitoringClient *mc;
 
@@ -290,28 +313,37 @@ lookup_monitoring_client (struct MonitoringClient *head,
  */
 static struct MonitoringClient *
 setup_peer_monitoring_client (struct GNUNET_SERVER_Client *client,
-                         struct GNUNET_PeerIdentity *peer)
+                              const struct GNUNET_PeerIdentity *peer)
 {
   struct MonitoringClient *mc;
-  static struct GNUNET_PeerIdentity all_zeros;
 
-  GNUNET_assert (lookup_monitoring_client (peer_monitoring_clients_head, client) == NULL);
+  GNUNET_assert (NULL ==
+                 lookup_monitoring_client (peer_monitoring_clients_head,
+                                           client));
   mc = GNUNET_new (struct MonitoringClient);
   mc->client = client;
   mc->peer = *peer;
-  GNUNET_CONTAINER_DLL_insert (peer_monitoring_clients_head, peer_monitoring_clients_tail, mc);
-  GNUNET_SERVER_notification_context_add (peer_nc, client);
-
-  if (0 != memcmp (peer, &all_zeros, sizeof (struct GNUNET_PeerIdentity)))
-    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+  GNUNET_CONTAINER_DLL_insert (peer_monitoring_clients_head,
+                               peer_monitoring_clients_tail,
+                               mc);
+  GNUNET_SERVER_client_mark_monitor (client);
+  GNUNET_SERVER_notification_context_add (peer_nc,
+                                          client);
+  if (0 != memcmp (peer,
+                   &all_zeros,
+                   sizeof (struct GNUNET_PeerIdentity)))
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                 "Client %p started monitoring of the peer `%s'\n",
-                mc, GNUNET_i2s (peer));
+                mc,
+                GNUNET_i2s (peer));
   else
-    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-              "Client %p started monitoring all peers\n", mc);
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Client %p started monitoring all peers\n",
+                mc);
   return mc;
 }
 
+
 /**
  * Setup a new monitoring client using the given server client handle and
  * the peer identity.
@@ -323,32 +355,39 @@ setup_peer_monitoring_client (struct GNUNET_SERVER_Client *client,
  */
 static struct MonitoringClient *
 setup_val_monitoring_client (struct GNUNET_SERVER_Client *client,
-                         struct GNUNET_PeerIdentity *peer)
+                             struct GNUNET_PeerIdentity *peer)
 {
   struct MonitoringClient *mc;
-  static struct GNUNET_PeerIdentity all_zeros;
 
-  GNUNET_assert (lookup_monitoring_client (val_monitoring_clients_head, client) == NULL);
+  GNUNET_assert (NULL ==
+                 lookup_monitoring_client (val_monitoring_clients_head,
+                                           client));
   mc = GNUNET_new (struct MonitoringClient);
   mc->client = client;
   mc->peer = *peer;
-  GNUNET_CONTAINER_DLL_insert (val_monitoring_clients_head, val_monitoring_clients_tail, mc);
+  GNUNET_CONTAINER_DLL_insert (val_monitoring_clients_head,
+                               val_monitoring_clients_tail,
+                               mc);
   GNUNET_SERVER_notification_context_add (val_nc, client);
 
-  if (0 != memcmp (peer, &all_zeros, sizeof (struct GNUNET_PeerIdentity)))
-    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+  if (0 != memcmp (peer,
+                   &all_zeros,
+                   sizeof (struct GNUNET_PeerIdentity)))
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                 "Client %p started monitoring of the peer `%s'\n",
-                mc, GNUNET_i2s (peer));
+                mc,
+                GNUNET_i2s (peer));
   else
-    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-              "Client %p started monitoring all peers\n", mc);
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Client %p started monitoring all peers\n",
+                mc);
   return mc;
 }
 
 
 /**
  * Function called to notify a client about the socket being ready to
- * queue more data.  "buf" will be NULL and "size" zero if the socket
+ * queue more data.  @a buf will be NULL and @a size zero if the socket
  * was closed for writing in the meantime.
  *
  * @param cls closure
@@ -357,7 +396,9 @@ setup_val_monitoring_client (struct GNUNET_SERVER_Client *client,
  * @return number of bytes written to @a buf
  */
 static size_t
-transmit_to_client_callback (void *cls, size_t size, void *buf)
+transmit_to_client_callback (void *cls,
+                             size_t size,
+                             void *buf)
 {
   struct TransportClient *tc = cls;
   struct ClientMessageQueueEntry *q;
@@ -383,7 +424,8 @@ transmit_to_client_callback (void *cls, size_t size, void *buf)
       break;
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                 "Transmitting message of type %u to client %p.\n",
-                ntohs (msg->type), tc);
+                ntohs (msg->type),
+                tc);
     GNUNET_CONTAINER_DLL_remove (tc->message_queue_head,
                                  tc->message_queue_tail,
                                  q);
@@ -425,11 +467,11 @@ unicast (struct TransportClient *tc,
     GNUNET_break (0);
     return;
   }
-
-  if ((tc->message_count >= MAX_PENDING) && (GNUNET_YES == may_drop))
+  if ( (tc->message_count >= MAX_PENDING) &&
+       (GNUNET_YES == may_drop) )
   {
-    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-                _("Dropping message of type %u and size %u, have %u/%u messages pending\n"),
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Dropping message of type %u and size %u, have %u/%u messages pending\n",
                 ntohs (msg->type),
                 ntohs (msg->size),
                 tc->message_count,
@@ -445,7 +487,8 @@ unicast (struct TransportClient *tc,
   q = GNUNET_malloc (sizeof (struct ClientMessageQueueEntry) + msize);
   memcpy (&q[1], msg, msize);
   GNUNET_CONTAINER_DLL_insert_tail (tc->message_queue_head,
-                                    tc->message_queue_tail, q);
+                                    tc->message_queue_tail,
+                                    q);
   tc->message_count++;
   if (NULL != tc->th)
     return;
@@ -461,28 +504,31 @@ unicast (struct TransportClient *tc,
  * Called whenever a client is disconnected.  Frees our
  * resources associated with that client.
  *
- * @param cls closure
+ * @param cls closure, NULL
  * @param client identification of the client
  */
 static void
-client_disconnect_notification (void *cls, struct GNUNET_SERVER_Client *client)
+client_disconnect_notification (void *cls,
+                                struct GNUNET_SERVER_Client *client)
 {
   struct TransportClient *tc;
   struct MonitoringClient *mc;
   struct ClientMessageQueueEntry *mqe;
 
-  if (client == NULL)
+  if (NULL == client)
     return;
-  mc = lookup_monitoring_client (peer_monitoring_clients_head, client);
-  if (mc != NULL)
+  mc = lookup_monitoring_client (peer_monitoring_clients_head,
+                                 client);
+  if (NULL != mc)
   {
     GNUNET_CONTAINER_DLL_remove (peer_monitoring_clients_head,
                                  peer_monitoring_clients_tail,
                                  mc);
     GNUNET_free (mc);
   }
-  mc = lookup_monitoring_client (val_monitoring_clients_head, client);
-  if (mc != NULL)
+  mc = lookup_monitoring_client (val_monitoring_clients_head,
+                                 client);
+  if (NULL != mc)
   {
     GNUNET_CONTAINER_DLL_remove (val_monitoring_clients_head,
                                  val_monitoring_clients_tail,
@@ -490,19 +536,24 @@ client_disconnect_notification (void *cls, struct GNUNET_SERVER_Client *client)
     GNUNET_free (mc);
   }
   tc = lookup_client (client);
-  if (tc == NULL)
+  if (NULL == tc)
     return;
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG | GNUNET_ERROR_TYPE_BULK,
-              "Client %p disconnected, cleaning up.\n", tc);
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Client %p disconnected, cleaning up.\n",
+              tc);
   while (NULL != (mqe = tc->message_queue_head))
   {
-    GNUNET_CONTAINER_DLL_remove (tc->message_queue_head, tc->message_queue_tail,
+    GNUNET_CONTAINER_DLL_remove (tc->message_queue_head,
+                                 tc->message_queue_tail,
                                  mqe);
     tc->message_count--;
     GNUNET_free (mqe);
   }
-  GNUNET_CONTAINER_DLL_remove (clients_head, clients_tail, tc);
-  if (tc->th != NULL)
+  GNUNET_CONTAINER_DLL_remove (clients_head,
+                               clients_tail,
+                               tc);
+  GNUNET_SERVER_client_set_user_context (client, NULL);
+  if (NULL != tc->th)
   {
     GNUNET_SERVER_notify_transmit_ready_cancel (tc->th);
     tc->th = NULL;
@@ -526,29 +577,24 @@ client_disconnect_notification (void *cls, struct GNUNET_SERVER_Client *client)
  */
 static void
 notify_client_about_neighbour (void *cls,
-    const struct GNUNET_PeerIdentity *peer,
-    const struct GNUNET_HELLO_Address *address,
-    enum GNUNET_TRANSPORT_PeerState state,
-    struct GNUNET_TIME_Absolute state_timeout,
-    struct GNUNET_BANDWIDTH_Value32NBO bandwidth_in,
-    struct GNUNET_BANDWIDTH_Value32NBO bandwidth_out)
+                               const struct GNUNET_PeerIdentity *peer,
+                               const struct GNUNET_HELLO_Address *address,
+                               enum GNUNET_TRANSPORT_PeerState state,
+                               struct GNUNET_TIME_Absolute state_timeout,
+                               struct GNUNET_BANDWIDTH_Value32NBO bandwidth_in,
+                               struct GNUNET_BANDWIDTH_Value32NBO bandwidth_out)
 {
   struct TransportClient *tc = cls;
-  struct ConnectInfoMessage *cim;
-  size_t size = sizeof (struct ConnectInfoMessage);
-  char buf[size] GNUNET_ALIGN;
+  struct ConnectInfoMessage cim;
 
   if (GNUNET_NO == GST_neighbours_test_connected (peer))
     return;
-
-  GNUNET_assert (size < GNUNET_SERVER_MAX_MESSAGE_SIZE);
-  cim = (struct ConnectInfoMessage *) buf;
-  cim->header.size = htons (size);
-  cim->header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_CONNECT);
-  cim->id = *peer;
-  cim->quota_in = bandwidth_in;
-  cim->quota_out = bandwidth_out;
-  unicast (tc, &cim->header, GNUNET_NO);
+  cim.header.size = htons (sizeof (struct ConnectInfoMessage));
+  cim.header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_CONNECT);
+  cim.id = *peer;
+  cim.quota_in = bandwidth_in;
+  cim.quota_out = bandwidth_out;
+  unicast (tc, &cim.header, GNUNET_NO);
 }
 
 
@@ -562,48 +608,52 @@ notify_client_about_neighbour (void *cls,
  * @param message the start message that was sent
  */
 static void
-clients_handle_start (void *cls, struct GNUNET_SERVER_Client *client,
+clients_handle_start (void *cls,
+                      struct GNUNET_SERVER_Client *client,
                       const struct GNUNET_MessageHeader *message)
 {
   const struct StartMessage *start;
+  const struct GNUNET_MessageHeader *hello;
   struct TransportClient *tc;
   uint32_t options;
 
   tc = lookup_client (client);
-
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG | GNUNET_ERROR_TYPE_BULK,
-              "Client %p sent START\n", tc);
-  if (tc != NULL)
+  if (NULL != tc)
   {
     /* got 'start' twice from the same client, not allowed */
-    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG | GNUNET_ERROR_TYPE_BULK,
-                "TransportClient %p ServerClient %p sent multiple START messages\n",
-                tc, tc->client);
     GNUNET_break (0);
-    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
+    GNUNET_SERVER_receive_done (client,
+                                GNUNET_SYSERR);
     return;
   }
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Client %p sent START\n",
+              client);
   start = (const struct StartMessage *) message;
   options = ntohl (start->options);
   if ((0 != (1 & options)) &&
       (0 !=
-       memcmp (&start->self, &GST_my_identity,
+       memcmp (&start->self,
+               &GST_my_identity,
                sizeof (struct GNUNET_PeerIdentity))))
   {
     /* client thinks this is a different peer, reject */
-    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
-                _
-                ("Rejecting control connection from peer `%s', which is not me!\n"),
-                GNUNET_i2s (&start->self));
-    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
+    GNUNET_break (0);
+    GNUNET_SERVER_receive_done (client,
+                                GNUNET_SYSERR);
     return;
   }
   tc = setup_client (client);
   tc->send_payload = (0 != (2 & options));
-  unicast (tc, GST_hello_get (), GNUNET_NO);
-  GST_neighbours_iterate (&notify_client_about_neighbour, tc);
-  GNUNET_CONTAINER_DLL_insert (clients_head, clients_tail, tc);
-  GNUNET_SERVER_receive_done (client, GNUNET_OK);
+  hello = GST_hello_get ();
+  if (NULL != hello)
+    unicast (tc,
+             hello,
+             GNUNET_NO);
+  GST_neighbours_iterate (&notify_client_about_neighbour,
+                          tc);
+  GNUNET_SERVER_receive_done (client,
+                              GNUNET_OK);
 }
 
 
@@ -615,7 +665,8 @@ clients_handle_start (void *cls, struct GNUNET_SERVER_Client *client,
  * @param message the HELLO message
  */
 static void
-clients_handle_hello (void *cls, struct GNUNET_SERVER_Client *client,
+clients_handle_hello (void *cls,
+                      struct GNUNET_SERVER_Client *client,
                       const struct GNUNET_MessageHeader *message)
 {
   GST_validation_handle_hello (message);
@@ -624,7 +675,7 @@ clients_handle_hello (void *cls, struct GNUNET_SERVER_Client *client,
 
 
 /**
- * Closure for 'handle_send_transmit_continuation'
+ * Closure for #handle_send_transmit_continuation()
  */
 struct SendTransmitContinuationContext
 {
@@ -637,6 +688,11 @@ struct SendTransmitContinuationContext
    * Peer that was the target.
    */
   struct GNUNET_PeerIdentity target;
+
+  /**
+   * At what time did we receive the message?
+   */
+  struct GNUNET_TIME_Absolute send_time;
 };
 
 
@@ -650,25 +706,52 @@ struct SendTransmitContinuationContext
  * @param bytes_on_wire bytes sent on wire
  */
 static void
-handle_send_transmit_continuation (void *cls, int success,
+handle_send_transmit_continuation (void *cls,
+                                   int success,
                                    size_t bytes_payload,
                                    size_t bytes_on_wire)
 {
   struct SendTransmitContinuationContext *stcc = cls;
   struct SendOkMessage send_ok_msg;
-
-  if (GNUNET_OK == success)
-    GST_neighbours_notify_payload_sent (&stcc->target, bytes_payload);
-
-  send_ok_msg.header.size = htons (sizeof (send_ok_msg));
-  send_ok_msg.header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_SEND_OK);
-  send_ok_msg.bytes_msg = htonl (bytes_payload);
-  send_ok_msg.bytes_physical = htonl (bytes_on_wire);
-  send_ok_msg.success = htonl (success);
-  send_ok_msg.latency =
-      GNUNET_TIME_relative_hton (GNUNET_TIME_UNIT_FOREVER_REL);
-  send_ok_msg.peer = stcc->target;
-  GST_clients_unicast (stcc->client, &send_ok_msg.header, GNUNET_NO);
+  struct GNUNET_TIME_Relative delay;
+  const struct GNUNET_HELLO_Address *addr;
+
+  delay = GNUNET_TIME_absolute_get_duration (stcc->send_time);
+  addr = GST_neighbour_get_current_address (&stcc->target);
+  if (delay.rel_value_us > GNUNET_CONSTANTS_LATENCY_WARN.rel_value_us)
+    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                "It took us %s to send %u/%u bytes to %s (%d, %s)\n",
+                GNUNET_STRINGS_relative_time_to_string (delay,
+                                                        GNUNET_YES),
+                (unsigned int) bytes_payload,
+                (unsigned int) bytes_on_wire,
+                GNUNET_i2s (&stcc->target),
+                success,
+                (NULL != addr) ? addr->transport_name : "%");
+  else
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "It took us %s to send %u/%u bytes to %s (%d, %s)\n",
+                GNUNET_STRINGS_relative_time_to_string (delay,
+                                                        GNUNET_YES),
+                (unsigned int) bytes_payload,
+                (unsigned int) bytes_on_wire,
+                GNUNET_i2s (&stcc->target),
+                success,
+                (NULL != addr) ? addr->transport_name : "%");
+
+  if (GST_neighbours_test_connected (&stcc->target))
+  {
+    /* Only send confirmation if we are still connected */
+    send_ok_msg.header.size = htons (sizeof (send_ok_msg));
+    send_ok_msg.header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_SEND_OK);
+    send_ok_msg.bytes_msg = htonl (bytes_payload);
+    send_ok_msg.bytes_physical = htonl (bytes_on_wire);
+    send_ok_msg.success = htonl (success);
+    send_ok_msg.peer = stcc->target;
+    GST_clients_unicast (stcc->client,
+                         &send_ok_msg.header,
+                         GNUNET_NO);
+  }
   GNUNET_SERVER_client_drop (stcc->client);
   GNUNET_free (stcc);
 }
@@ -698,7 +781,8 @@ clients_handle_send (void *cls,
   {
     /* client asked for transmission before 'START' */
     GNUNET_break (0);
-    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
+    GNUNET_SERVER_receive_done (client,
+                                GNUNET_SYSERR);
     return;
   }
 
@@ -707,7 +791,8 @@ clients_handle_send (void *cls,
       sizeof (struct OutboundMessage) + sizeof (struct GNUNET_MessageHeader))
   {
     GNUNET_break (0);
-    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
+    GNUNET_SERVER_receive_done (client,
+                                GNUNET_SYSERR);
     return;
   }
   obm = (const struct OutboundMessage *) message;
@@ -716,16 +801,11 @@ clients_handle_send (void *cls,
   if (msize < sizeof (struct GNUNET_MessageHeader))
   {
     GNUNET_break (0);
-    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
+    GNUNET_SERVER_receive_done (client,
+                                GNUNET_SYSERR);
     return;
   }
 
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              "Received `%s' request from client with target `%4s' and first message of type %u and total size %u\n",
-              "SEND",
-              GNUNET_i2s (&obm->peer),
-              ntohs (obmm->type),
-              msize);
   if (GNUNET_NO == GST_neighbours_test_connected (&obm->peer))
   {
     /* not connected, not allowed to send; can happen due to asynchronous operations */
@@ -736,167 +816,178 @@ clients_handle_send (void *cls,
                               gettext_noop
                               ("# bytes payload dropped (other peer was not connected)"),
                               msize, GNUNET_NO);
-    GNUNET_SERVER_receive_done (client, GNUNET_OK);
+    GNUNET_SERVER_receive_done (client,
+                                GNUNET_OK);
     return;
   }
-  GNUNET_SERVER_receive_done (client, GNUNET_OK);
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Received SEND request for `%s' and first message of type %u and total size %u\n",
+              GNUNET_i2s (&obm->peer),
+              ntohs (obmm->type),
+              msize);
+  GNUNET_SERVER_receive_done (client,
+                              GNUNET_OK);
   stcc = GNUNET_new (struct SendTransmitContinuationContext);
   stcc->target = obm->peer;
   stcc->client = client;
+  stcc->send_time = GNUNET_TIME_absolute_get ();
   GNUNET_SERVER_client_keep (client);
-  GST_manipulation_send (&obm->peer, obmm, msize,
-                       GNUNET_TIME_relative_ntoh (obm->timeout),
-                       &handle_send_transmit_continuation, stcc);
+  GST_manipulation_send (&obm->peer,
+                         obmm,
+                         msize,
+                         GNUNET_TIME_relative_ntoh (obm->timeout),
+                         &handle_send_transmit_continuation,
+                         stcc);
 }
 
 
 /**
- * Try to initiate a connection to the given peer if the blacklist
- * allowed it.
+ * Handle request connect message
  *
- * @param cls closure (unused, NULL)
- * @param peer identity of peer that was tested
- * @param result #GNUNET_OK if the connection is allowed,
- *               #GNUNET_NO if not
+ * @param cls closure (always NULL)
+ * @param client identification of the client
+ * @param message the actual message
  */
 static void
-try_connect_if_allowed (void *cls,
-                        const struct GNUNET_PeerIdentity *peer,
-                        int result)
+clients_handle_request_connect (void *cls,
+                                struct GNUNET_SERVER_Client *client,
+                                const struct GNUNET_MessageHeader *message)
 {
-  if (GNUNET_OK != result)
+  const struct TransportRequestConnectMessage *trcm;
+
+  trcm = (const struct TransportRequestConnectMessage *) message;
+  GNUNET_break (0 == ntohl (trcm->reserved));
+  GNUNET_STATISTICS_update (GST_stats,
+                            gettext_noop
+                            ("# REQUEST CONNECT messages received"), 1,
+                            GNUNET_NO);
+  if (0 == memcmp (&trcm->peer,
+                   &GST_my_identity,
+                   sizeof (struct GNUNET_PeerIdentity)))
   {
-    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-                _("Blacklist refuses connection attempt to peer `%s'\n"),
-                GNUNET_i2s (peer));
-    return;                     /* not allowed */
+    GNUNET_break (0);
+    GNUNET_SERVER_receive_done (client,
+                                GNUNET_OK);
+    return;
   }
-
-  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-              _("Blacklist allows connection attempt to peer `%s'\n"),
-              GNUNET_i2s (peer));
-
-  GST_neighbours_try_connect (peer);
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Received a request connect message for peer `%s'\n",
+              GNUNET_i2s (&trcm->peer));
+  GST_neighbours_try_connect (&trcm->peer);
+  GNUNET_SERVER_receive_done (client, GNUNET_OK);
 }
 
 
 /**
- * Handle request connect message
+ * Handle request disconnect message
  *
  * @param cls closure (always NULL)
  * @param client identification of the client
  * @param message the actual message
  */
 static void
-clients_handle_request_connect (void *cls, struct GNUNET_SERVER_Client *client,
-                                const struct GNUNET_MessageHeader *message)
+clients_handle_request_disconnect (void *cls,
+                                   struct GNUNET_SERVER_Client *client,
+                                   const struct GNUNET_MessageHeader *message)
 {
-  const struct TransportRequestConnectMessage *trcm =
-      (const struct TransportRequestConnectMessage *) message;
-
-  if (GNUNET_YES == ntohl (trcm->connect))
-  {
-    GNUNET_STATISTICS_update (GST_stats,
-                              gettext_noop
-                              ("# REQUEST CONNECT messages received"), 1,
-                              GNUNET_NO);
-
-    if (0 == memcmp (&trcm->peer, &GST_my_identity,
-                  sizeof (struct GNUNET_PeerIdentity)))
-    {
-      GNUNET_break_op (0);
-      GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
-                  "Received a request connect message myself `%s'\n",
-                  GNUNET_i2s (&trcm->peer));
-    }
-    else
-    {
-      GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-                  _("Received a request connect message for peer `%s'\n"),
-                  GNUNET_i2s (&trcm->peer));
-
-      (void) GST_blacklist_test_allowed (&trcm->peer, NULL, &try_connect_if_allowed,
-                                       NULL);
-    }
-  }
-  else if (GNUNET_NO == ntohl (trcm->connect))
-  {
-    GNUNET_STATISTICS_update (GST_stats,
-                              gettext_noop
-                              ("# REQUEST DISCONNECT messages received"), 1,
-                              GNUNET_NO);
-
-    if (0 == memcmp (&trcm->peer, &GST_my_identity,
-                  sizeof (struct GNUNET_PeerIdentity)))
-    {
-      GNUNET_break_op (0);
-      GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
-                  "Received a request disconnect message myself `%s'\n",
-                  GNUNET_i2s (&trcm->peer));
-    }
-    else
-    {
-      GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-                  _("Received a request disconnect message for peer `%s'\n"),
-                  GNUNET_i2s (&trcm->peer));
-      (void) GST_neighbours_force_disconnect (&trcm->peer);
-    }
-  }
-  else
+  const struct TransportRequestDisconnectMessage *trdm;
+
+  trdm = (const struct TransportRequestDisconnectMessage *) message;
+  GNUNET_break (0 == ntohl (trdm->reserved));
+  GNUNET_STATISTICS_update (GST_stats,
+                            gettext_noop
+                            ("# REQUEST DISCONNECT messages received"), 1,
+                            GNUNET_NO);
+  if (0 == memcmp (&trdm->peer,
+                   &GST_my_identity,
+                   sizeof (struct GNUNET_PeerIdentity)))
   {
-    GNUNET_break_op (0);
-    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
+    GNUNET_break (0);
+    GNUNET_SERVER_receive_done (client, GNUNET_OK);
     return;
   }
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Received a request disconnect message for peer `%s'\n",
+              GNUNET_i2s (&trdm->peer));
+  (void) GST_neighbours_force_disconnect (&trdm->peer);
   GNUNET_SERVER_receive_done (client, GNUNET_OK);
 }
 
 
 /**
  * Take the given address and append it to the set of results sent back to
- * the client.
+ * the client.  This function may be called serveral times for a single
+ * conversion.   The last invocation will be with a @a address of
+ * NULL and a @a res of #GNUNET_OK.  Thus, to indicate conversion
+ * errors, the callback might be called first with @a address NULL and
+ * @a res being #GNUNET_SYSERR.  In that case, there will still be a
+ * subsequent call later with @a address NULL and @a res #GNUNET_OK.
  *
- * @param cls the transmission context used ('struct GNUNET_SERVER_TransmitContext*')
- * @param buf text to transmit
+ * @param cls the transmission context used (`struct GNUNET_SERVER_TransmitContext *`)
+ * @param buf text to transmit (contains the human-readable address, or NULL)
+ * @param res #GNUNET_OK if conversion was successful, #GNUNET_SYSERR on error,
+ *            never #GNUNET_NO
  */
 static void
-transmit_address_to_client (void *cls, const char *buf)
+transmit_address_to_client (void *cls,
+                            const char *buf,
+                            int res)
 {
   struct AddressToStringContext *actx = cls;
   struct AddressToStringResultMessage *atsm;
   size_t len;
+  size_t slen;
 
-  if (NULL != buf)
-  {
-    len = sizeof (struct AddressToStringResultMessage) + strlen (buf) + 1;
-    atsm = GNUNET_malloc (len);
-    atsm->header.size = ntohs (len);
-    atsm->header.type = ntohs (GNUNET_MESSAGE_TYPE_TRANSPORT_ADDRESS_TO_STRING_REPLY);
-    atsm->res = htonl (GNUNET_YES);
-    atsm->addr_len = htonl (strlen (buf) + 1);
-    memcpy (&atsm[1], buf, strlen (buf) + 1);
-  }
-  else
+  GNUNET_assert ( (GNUNET_OK == res) ||
+                  (GNUNET_SYSERR == res) );
+  if (NULL == buf)
   {
     len = sizeof (struct AddressToStringResultMessage);
-
     atsm = GNUNET_malloc (len);
     atsm->header.size = ntohs (len);
     atsm->header.type = ntohs (GNUNET_MESSAGE_TYPE_TRANSPORT_ADDRESS_TO_STRING_REPLY);
-    atsm->res = htonl (GNUNET_NO);
-    atsm->addr_len = htonl (0);
-  }
-
-  if (NULL == buf)
-  {
-    /* Address could not be converted */
-    GNUNET_SERVER_transmit_context_append_message (actx->tc, (const struct GNUNET_MessageHeader *)atsm);
-    GNUNET_SERVER_transmit_context_run (actx->tc, GNUNET_TIME_UNIT_FOREVER_REL);
-    GNUNET_CONTAINER_DLL_remove (a2s_head, a2s_tail, actx);
-    GNUNET_free (actx);
-    return;
+    if (GNUNET_OK == res)
+    {
+      /* this was the last call, transmit */
+      atsm->res = htonl (GNUNET_OK);
+      atsm->addr_len = htonl (0);
+      GNUNET_SERVER_transmit_context_append_message (actx->tc,
+                                                     (const struct GNUNET_MessageHeader *) atsm);
+      GNUNET_SERVER_transmit_context_run (actx->tc,
+                                          GNUNET_TIME_UNIT_FOREVER_REL);
+      GNUNET_CONTAINER_DLL_remove (a2s_head,
+                                   a2s_tail,
+                                   actx);
+      GNUNET_free (atsm);
+      GNUNET_free (actx);
+      return;
+    }
+    if (GNUNET_SYSERR == res)
+    {
+      /* address conversion failed, but there will be more callbacks */
+      atsm->res = htonl (GNUNET_SYSERR);
+      atsm->addr_len = htonl (0);
+      GNUNET_SERVER_transmit_context_append_message (actx->tc,
+                                                     (const struct GNUNET_MessageHeader *) atsm);
+      GNUNET_free (atsm);
+      return;
+    }
   }
-  GNUNET_SERVER_transmit_context_append_message (actx->tc, (const struct GNUNET_MessageHeader *) atsm);
+  GNUNET_assert (GNUNET_OK == res);
+  /* succesful conversion, append*/
+  slen = strlen (buf) + 1;
+  len = sizeof (struct AddressToStringResultMessage) + slen;
+  atsm = GNUNET_malloc (len);
+  atsm->header.size = ntohs (len);
+  atsm->header.type = ntohs (GNUNET_MESSAGE_TYPE_TRANSPORT_ADDRESS_TO_STRING_REPLY);
+  atsm->res = htonl (GNUNET_YES);
+  atsm->addr_len = htonl (slen);
+  memcpy (&atsm[1],
+          buf,
+          slen);
+  GNUNET_SERVER_transmit_context_append_message (actx->tc,
+                                                 (const struct GNUNET_MessageHeader *) atsm);
+  GNUNET_free (atsm);
 }
 
 
@@ -953,21 +1044,38 @@ clients_handle_address_to_string (void *cls,
   papi = GST_plugins_printer_find (plugin_name);
   if (NULL == papi)
   {
+    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                "Failed to find plugin `%s'\n",
+                plugin_name);
     atsm.header.size = ntohs (sizeof (struct AddressToStringResultMessage));
     atsm.header.type = ntohs (GNUNET_MESSAGE_TYPE_TRANSPORT_ADDRESS_TO_STRING_REPLY);
-    atsm.res = htonl (GNUNET_NO);
+    atsm.res = htonl (GNUNET_SYSERR);
     atsm.addr_len = htonl (0);
     GNUNET_SERVER_transmit_context_append_message (tc,
-        (const struct GNUNET_MessageHeader *) &atsm);
-    GNUNET_SERVER_transmit_context_run (tc, rtimeout);
+                                                   &atsm.header);
+    atsm.header.size = ntohs (sizeof (struct AddressToStringResultMessage));
+    atsm.header.type = ntohs (GNUNET_MESSAGE_TYPE_TRANSPORT_ADDRESS_TO_STRING_REPLY);
+    atsm.res = htonl (GNUNET_OK);
+    atsm.addr_len = htonl (0);
+    GNUNET_SERVER_transmit_context_append_message (tc,
+                                                   &atsm.header);
+    GNUNET_SERVER_transmit_context_run (tc, GNUNET_TIME_UNIT_FOREVER_REL);
     return;
   }
   actx = GNUNET_new (struct AddressToStringContext);
   actx->tc = tc;
   GNUNET_CONTAINER_DLL_insert (a2s_head, a2s_tail, actx);
   GNUNET_SERVER_disable_receive_done_warning (client);
-  papi->address_pretty_printer (papi->cls, plugin_name, address, address_len,
-                                numeric, rtimeout, &transmit_address_to_client,
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Pretty-printing address of %u bytes using plugin `%s'\n",
+              address_len,
+              plugin_name);
+  papi->address_pretty_printer (papi->cls,
+                                plugin_name,
+                                address, address_len,
+                                numeric,
+                                rtimeout,
+                                &transmit_address_to_client,
                                 actx);
 }
 
@@ -996,7 +1104,10 @@ compose_address_iterate_response_message (const struct GNUNET_PeerIdentity *peer
     alen = address->address_length;
   }
   else
-    tlen = alen = 0;
+  {
+    tlen = 0;
+    alen = 0;
+  }
   size = (sizeof (struct PeerIterateResponseMessage) + alen + tlen);
   msg = GNUNET_malloc (size);
   msg->header.size = htons (size);
@@ -1017,6 +1128,7 @@ compose_address_iterate_response_message (const struct GNUNET_PeerIdentity *peer
   return msg;
 }
 
+
 /**
  * Compose #PeerIterateResponseMessage using the given peer and address.
  *
@@ -1026,7 +1138,7 @@ compose_address_iterate_response_message (const struct GNUNET_PeerIdentity *peer
  */
 static struct ValidationIterateResponseMessage *
 compose_validation_iterate_response_message (const struct GNUNET_PeerIdentity *peer,
-                                          const struct GNUNET_HELLO_Address *address)
+                                             const struct GNUNET_HELLO_Address *address)
 {
   struct ValidationIterateResponseMessage *msg;
   size_t size;
@@ -1041,7 +1153,10 @@ compose_validation_iterate_response_message (const struct GNUNET_PeerIdentity *p
     alen = address->address_length;
   }
   else
-    tlen = alen = 0;
+  {
+    tlen = 0;
+    alen = 0;
+  }
   size = (sizeof (struct ValidationIterateResponseMessage) + alen + tlen);
   msg = GNUNET_malloc (size);
   msg->header.size = htons (size);
@@ -1062,20 +1177,34 @@ compose_validation_iterate_response_message (const struct GNUNET_PeerIdentity *p
   return msg;
 }
 
+
+/**
+ * Context for #send_validation_information() and
+ * #send_peer_information().
+ */
 struct IterationContext
 {
+  /**
+   * Context to use for the transmission.
+   */
   struct GNUNET_SERVER_TransmitContext *tc;
 
+  /**
+   * Which peers do we care about?
+   */
   struct GNUNET_PeerIdentity id;
 
+  /**
+   * #GNUNET_YES if @e id should be ignored because we want all peers.
+   */
   int all;
 };
 
+
 /**
  * Output information of validation entries to the given client.
  *
- * @param cls the 'struct IterationContext'
- * @param peer identity of the neighbour
+ * @param cls the `struct IterationContext *`
  * @param address the address
  * @param last_validation point in time when last validation was performed
  * @param valid_until point in time how long address is valid
@@ -1084,37 +1213,36 @@ struct IterationContext
  */
 static void
 send_validation_information (void *cls,
-    const struct GNUNET_PeerIdentity *peer,
-    const struct GNUNET_HELLO_Address *address,
-    struct GNUNET_TIME_Absolute last_validation,
-    struct GNUNET_TIME_Absolute valid_until,
-    struct GNUNET_TIME_Absolute next_validation,
-    enum GNUNET_TRANSPORT_ValidationState state)
+                             const struct GNUNET_HELLO_Address *address,
+                             struct GNUNET_TIME_Absolute last_validation,
+                             struct GNUNET_TIME_Absolute valid_until,
+                             struct GNUNET_TIME_Absolute next_validation,
+                             enum GNUNET_TRANSPORT_ValidationState state)
 {
   struct IterationContext *pc = cls;
   struct ValidationIterateResponseMessage *msg;
 
-  if ( (GNUNET_YES == pc->all) ||
-       (0 == memcmp (peer, &pc->id, sizeof (pc->id))) )
-  {
-    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-        "Sending information about for validation entry for peer `%s' using address `%s'\n",
-        GNUNET_i2s(peer), (address != NULL) ? GST_plugins_a2s (address) : "<none>");
-    msg = compose_validation_iterate_response_message (peer, address);
-    msg->last_validation = GNUNET_TIME_absolute_hton(last_validation);
-    msg->valid_until = GNUNET_TIME_absolute_hton(valid_until);
-    msg->next_validation = GNUNET_TIME_absolute_hton(next_validation);
-    msg->state = htonl ((uint32_t) state);
-    GNUNET_SERVER_transmit_context_append_message (pc->tc, &msg->header);
-    GNUNET_free (msg);
-  }
+  if ( (GNUNET_YES != pc->all) &&
+       (0 != memcmp (&address->peer, &pc->id, sizeof (pc->id))) )
+    return;
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Sending information about for validation entry for peer `%s' using address `%s'\n",
+              GNUNET_i2s (&address->peer),
+              (NULL != address) ? GST_plugins_a2s (address) : "<none>");
+  msg = compose_validation_iterate_response_message (&address->peer, address);
+  msg->last_validation = GNUNET_TIME_absolute_hton(last_validation);
+  msg->valid_until = GNUNET_TIME_absolute_hton(valid_until);
+  msg->next_validation = GNUNET_TIME_absolute_hton(next_validation);
+  msg->state = htonl ((uint32_t) state);
+  GNUNET_SERVER_transmit_context_append_message (pc->tc, &msg->header);
+  GNUNET_free (msg);
 }
 
 
 /**
  * Output information of neighbours to the given client.
  *
- * @param cls the 'struct PeerIterationContext'
+ * @param cls the `struct PeerIterationContext *`
  * @param peer identity of the neighbour
  * @param address the address
  * @param state current state this peer is in
@@ -1124,34 +1252,32 @@ send_validation_information (void *cls,
  */
 static void
 send_peer_information (void *cls,
-    const struct GNUNET_PeerIdentity *peer,
-    const struct GNUNET_HELLO_Address *address,
-    enum GNUNET_TRANSPORT_PeerState state,
-    struct GNUNET_TIME_Absolute state_timeout,
-    struct GNUNET_BANDWIDTH_Value32NBO bandwidth_in,
-    struct GNUNET_BANDWIDTH_Value32NBO bandwidth_out)
+                       const struct GNUNET_PeerIdentity *peer,
+                       const struct GNUNET_HELLO_Address *address,
+                       enum GNUNET_TRANSPORT_PeerState state,
+                       struct GNUNET_TIME_Absolute state_timeout,
+                       struct GNUNET_BANDWIDTH_Value32NBO bandwidth_in,
+                       struct GNUNET_BANDWIDTH_Value32NBO bandwidth_out)
 {
   struct IterationContext *pc = cls;
   struct PeerIterateResponseMessage *msg;
 
-  if ( (GNUNET_YES == pc->all) ||
-       (0 == memcmp (peer, &pc->id, sizeof (pc->id))) )
-  {
-    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-        "Sending information about `%s' using address `%s' in state `%s'\n",
-        GNUNET_i2s(peer),
-        (address != NULL) ? GST_plugins_a2s (address) : "<none>",
-        GNUNET_TRANSPORT_ps2s (state));
-    msg = compose_address_iterate_response_message (peer, address);
-    msg->state = htonl (state);
-    msg->state_timeout = GNUNET_TIME_absolute_hton(state_timeout);
-    GNUNET_SERVER_transmit_context_append_message (pc->tc, &msg->header);
-    GNUNET_free (msg);
-  }
+  if ( (GNUNET_YES != pc->all) &&
+       (0 != memcmp (peer, &pc->id, sizeof (pc->id))) )
+    return;
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Sending information about `%s' using address `%s' in state `%s'\n",
+              GNUNET_i2s(peer),
+              (NULL != address) ? GST_plugins_a2s (address) : "<none>",
+              GNUNET_TRANSPORT_ps2s (state));
+  msg = compose_address_iterate_response_message (peer, address);
+  msg->state = htonl (state);
+  msg->state_timeout = GNUNET_TIME_absolute_hton(state_timeout);
+  GNUNET_SERVER_transmit_context_append_message (pc->tc, &msg->header);
+  GNUNET_free (msg);
 }
 
 
-
 /**
  * Client asked to obtain information about a specific or all peers
  * Process the request.
@@ -1161,42 +1287,32 @@ send_peer_information (void *cls,
  * @param message the peer address information request
  */
 static void
-clients_handle_monitor_peers (void *cls, struct GNUNET_SERVER_Client *client,
-                                const struct GNUNET_MessageHeader *message)
+clients_handle_monitor_peers (void *cls,
+                              struct GNUNET_SERVER_Client *client,
+                              const struct GNUNET_MessageHeader *message)
 {
-  static struct GNUNET_PeerIdentity all_zeros;
   struct GNUNET_SERVER_TransmitContext *tc;
-  struct PeerMonitorMessage *msg;
+  const struct PeerMonitorMessage *msg;
   struct IterationContext pc;
 
-  if (ntohs (message->type) != GNUNET_MESSAGE_TYPE_TRANSPORT_MONITOR_PEER_REQUEST)
-  {
-    GNUNET_break (0);
-    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
-    return;
-  }
-  if (ntohs (message->size) != sizeof (struct PeerMonitorMessage))
-  {
-    GNUNET_break (0);
-    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
-    return;
-  }
-  msg = (struct PeerMonitorMessage *) message;
+  msg = (const struct PeerMonitorMessage *) message;
   if ( (GNUNET_YES != ntohl (msg->one_shot)) &&
-       (NULL != lookup_monitoring_client (peer_monitoring_clients_head, client)) )
+       (NULL != lookup_monitoring_client (peer_monitoring_clients_head,
+                                          client)) )
   {
-    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG | GNUNET_ERROR_TYPE_BULK,
-               "ServerClient %p tried to start monitoring twice\n",
-               client);
     GNUNET_break (0);
-    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
+    GNUNET_SERVER_receive_done (client,
+                                GNUNET_SYSERR);
     return;
   }
   GNUNET_SERVER_disable_receive_done_warning (client);
+  GNUNET_SERVER_client_mark_monitor (client);
   pc.tc = tc = GNUNET_SERVER_transmit_context_create (client);
 
   /* Send initial list */
-  if (0 == memcmp (&msg->peer, &all_zeros, sizeof (struct GNUNET_PeerIdentity)))
+  if (0 == memcmp (&msg->peer,
+                   &all_zeros,
+                   sizeof (struct GNUNET_PeerIdentity)))
   {
     /* iterate over all neighbours */
     pc.all = GNUNET_YES;
@@ -1208,19 +1324,23 @@ clients_handle_monitor_peers (void *cls, struct GNUNET_SERVER_Client *client,
     pc.all = GNUNET_NO;
     pc.id = msg->peer;
   }
-  GST_neighbours_iterate (&send_peer_information, &pc);
+  GST_neighbours_iterate (&send_peer_information,
+                          &pc);
 
   if (GNUNET_YES != ntohl (msg->one_shot))
   {
-    setup_peer_monitoring_client (client, &msg->peer);
+    setup_peer_monitoring_client (client,
+                                  &msg->peer);
   }
   else
   {
-    GNUNET_SERVER_transmit_context_append_data (tc, NULL, 0,
-        GNUNET_MESSAGE_TYPE_TRANSPORT_MONITOR_PEER_RESPONSE);
+    GNUNET_SERVER_transmit_context_append_data (tc,
+                                                NULL,
+                                                0,
+                                                GNUNET_MESSAGE_TYPE_TRANSPORT_MONITOR_PEER_RESPONSE);
   }
-
-  GNUNET_SERVER_transmit_context_run (tc, GNUNET_TIME_UNIT_FOREVER_REL);
+  GNUNET_SERVER_transmit_context_run (tc,
+                                      GNUNET_TIME_UNIT_FOREVER_REL);
 }
 
 
@@ -1233,10 +1353,10 @@ clients_handle_monitor_peers (void *cls, struct GNUNET_SERVER_Client *client,
  * @param message the peer address information request
  */
 static void
-clients_handle_monitor_validation (void *cls, struct GNUNET_SERVER_Client *client,
-                                const struct GNUNET_MessageHeader *message)
+clients_handle_monitor_validation (void *cls,
+                                  struct GNUNET_SERVER_Client *client,
+                                  const struct GNUNET_MessageHeader *message)
 {
-  static struct GNUNET_PeerIdentity all_zeros;
   struct GNUNET_SERVER_TransmitContext *tc;
   struct PeerMonitorMessage *msg;
   struct IterationContext pc;
@@ -1257,18 +1377,18 @@ clients_handle_monitor_validation (void *cls, struct GNUNET_SERVER_Client *clien
   if ( (GNUNET_YES != ntohl (msg->one_shot)) &&
        (NULL != lookup_monitoring_client (val_monitoring_clients_head, client)) )
   {
-    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG | GNUNET_ERROR_TYPE_BULK,
-                "ServerClient %p tried to start monitoring twice\n",
-                client);
     GNUNET_break (0);
     GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
     return;
   }
   GNUNET_SERVER_disable_receive_done_warning (client);
+  GNUNET_SERVER_client_mark_monitor (client);
   pc.tc = tc = GNUNET_SERVER_transmit_context_create (client);
 
   /* Send initial list */
-  if (0 == memcmp (&msg->peer, &all_zeros, sizeof (struct GNUNET_PeerIdentity)))
+  if (0 == memcmp (&msg->peer,
+                   &all_zeros,
+                   sizeof (struct GNUNET_PeerIdentity)))
   {
     /* iterate over all neighbours */
     pc.all = GNUNET_YES;
@@ -1280,8 +1400,8 @@ clients_handle_monitor_validation (void *cls, struct GNUNET_SERVER_Client *clien
     pc.all = GNUNET_NO;
     pc.id = msg->peer;
   }
-
-  GST_validation_iterate (&send_validation_information, &pc);
+  GST_validation_iterate (&send_validation_information,
+                          &pc);
 
   if (GNUNET_YES != ntohl (msg->one_shot))
   {
@@ -1290,11 +1410,129 @@ clients_handle_monitor_validation (void *cls, struct GNUNET_SERVER_Client *clien
   else
   {
     GNUNET_SERVER_transmit_context_append_data (tc, NULL, 0,
-        GNUNET_MESSAGE_TYPE_TRANSPORT_MONITOR_VALIDATION_RESPONSE);
+                                                GNUNET_MESSAGE_TYPE_TRANSPORT_MONITOR_VALIDATION_RESPONSE);
   }
   GNUNET_SERVER_transmit_context_run (tc, GNUNET_TIME_UNIT_FOREVER_REL);
 }
 
+
+/**
+ * Function called by the plugin with information about the
+ * current sessions managed by the plugin (for monitoring).
+ *
+ * @param cls closure
+ * @param session session handle this information is about,
+ *        NULL to indicate that we are "in sync" (initial
+ *        iteration complete)
+ * @param info information about the state of the session,
+ *        NULL if @a session is also NULL and we are
+ *        merely signalling that the initial iteration is over
+ */
+static void
+plugin_session_info_cb (void *cls,
+                       struct GNUNET_ATS_Session *session,
+                       const struct GNUNET_TRANSPORT_SessionInfo *info)
+{
+  struct TransportPluginMonitorMessage *msg;
+  struct GNUNET_MessageHeader sync;
+  size_t size;
+  size_t slen;
+  uint16_t alen;
+  char *name;
+  char *addr;
+
+  if (0 == GNUNET_SERVER_notification_context_get_size (plugin_nc))
+  {
+    GST_plugins_monitor_subscribe (NULL,
+                                   NULL);
+    return;
+  }
+  if ( (NULL == info) &&
+       (NULL == session) )
+  {
+    /* end of initial iteration */
+    if (NULL != sync_client)
+    {
+      sync.size = htons (sizeof (struct GNUNET_MessageHeader));
+      sync.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_MONITOR_PLUGIN_SYNC);
+      GNUNET_SERVER_notification_context_unicast (plugin_nc,
+                                                  sync_client,
+                                                  &sync,
+                                                  GNUNET_NO);
+      sync_client = NULL;
+    }
+    return;
+  }
+  GNUNET_assert (NULL != info);
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Plugin event for peer %s on transport %s\n",
+              GNUNET_i2s (&info->address->peer),
+              info->address->transport_name);
+  slen = strlen (info->address->transport_name) + 1;
+  alen = info->address->address_length;
+  size = sizeof (struct TransportPluginMonitorMessage) + slen + alen;
+  if (size > UINT16_MAX)
+  {
+    GNUNET_break (0);
+    return;
+  }
+  msg = GNUNET_malloc (size);
+  msg->header.size = htons (size);
+  msg->header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_MONITOR_PLUGIN_EVENT);
+  msg->session_state = htons ((uint16_t) info->state);
+  msg->is_inbound = htons ((int16_t) info->is_inbound);
+  msg->msgs_pending = htonl (info->num_msg_pending);
+  msg->bytes_pending = htonl (info->num_bytes_pending);
+  msg->timeout = GNUNET_TIME_absolute_hton (info->session_timeout);
+  msg->delay = GNUNET_TIME_absolute_hton (info->receive_delay);
+  msg->peer = info->address->peer;
+  msg->session_id = (uint64_t) (intptr_t) session;
+  msg->plugin_name_len = htons (slen);
+  msg->plugin_address_len = htons (alen);
+  name = (char *) &msg[1];
+  memcpy (name,
+          info->address->transport_name,
+          slen);
+  addr = &name[slen];
+  memcpy (addr,
+          info->address->address,
+          alen);
+  if (NULL != sync_client)
+    GNUNET_SERVER_notification_context_unicast (plugin_nc,
+                                                sync_client,
+                                                &msg->header,
+                                                GNUNET_NO);
+  else
+    GNUNET_SERVER_notification_context_broadcast (plugin_nc,
+                                                  &msg->header,
+                                                  GNUNET_NO);
+  GNUNET_free (msg);
+}
+
+
+/**
+ * Client asked to obtain information about all plugin connections.
+ *
+ * @param cls unused
+ * @param client the client
+ * @param message the peer address information request
+ */
+static void
+clients_handle_monitor_plugins (void *cls,
+                               struct GNUNET_SERVER_Client *client,
+                               const struct GNUNET_MessageHeader *message)
+{
+  GNUNET_SERVER_client_mark_monitor (client);
+  GNUNET_SERVER_disable_receive_done_warning (client);
+  GNUNET_SERVER_notification_context_add (plugin_nc,
+                                          client);
+  GNUNET_assert (NULL == sync_client);
+  sync_client = client;
+  GST_plugins_monitor_subscribe (&plugin_session_info_cb,
+                                 NULL);
+}
+
+
 /**
  * Start handling requests from clients.
  *
@@ -1313,6 +1551,9 @@ GST_clients_start (struct GNUNET_SERVER_Handle *server)
     {&clients_handle_request_connect, NULL,
      GNUNET_MESSAGE_TYPE_TRANSPORT_REQUEST_CONNECT,
      sizeof (struct TransportRequestConnectMessage)},
+    {&clients_handle_request_disconnect, NULL,
+     GNUNET_MESSAGE_TYPE_TRANSPORT_REQUEST_DISCONNECT,
+     sizeof (struct TransportRequestDisconnectMessage)},
     {&clients_handle_address_to_string, NULL,
      GNUNET_MESSAGE_TYPE_TRANSPORT_ADDRESS_TO_STRING, 0},
     {&clients_handle_monitor_peers, NULL,
@@ -1328,13 +1569,19 @@ GST_clients_start (struct GNUNET_SERVER_Handle *server)
      GNUNET_MESSAGE_TYPE_TRANSPORT_BLACKLIST_REPLY,
      sizeof (struct BlacklistMessage)},
     {&GST_manipulation_set_metric, NULL,
-     GNUNET_MESSAGE_TYPE_TRANSPORT_TRAFFIC_METRIC, 0},
+     GNUNET_MESSAGE_TYPE_TRANSPORT_TRAFFIC_METRIC,
+     sizeof (struct TrafficMetricMessage) },
+    {&clients_handle_monitor_plugins, NULL,
+     GNUNET_MESSAGE_TYPE_TRANSPORT_MONITOR_PLUGIN_START,
+     sizeof (struct GNUNET_MessageHeader) },
     {NULL, NULL, 0, 0}
   };
   peer_nc = GNUNET_SERVER_notification_context_create (server, 0);
   val_nc = GNUNET_SERVER_notification_context_create (server, 0);
+  plugin_nc = GNUNET_SERVER_notification_context_create (server, 0);
   GNUNET_SERVER_add_handlers (server, handlers);
-  GNUNET_SERVER_disconnect_notify (server, &client_disconnect_notification,
+  GNUNET_SERVER_disconnect_notify (server,
+                                   &client_disconnect_notification,
                                    NULL);
 }
 
@@ -1363,6 +1610,11 @@ GST_clients_stop ()
     GNUNET_SERVER_notification_context_destroy (val_nc);
     val_nc = NULL;
   }
+  if (NULL != plugin_nc)
+  {
+    GNUNET_SERVER_notification_context_destroy (plugin_nc);
+    plugin_nc = NULL;
+  }
 }
 
 
@@ -1373,14 +1625,20 @@ GST_clients_stop ()
  * @param may_drop #GNUNET_YES if the message can be dropped / is payload
  */
 void
-GST_clients_broadcast (const struct GNUNET_MessageHeader *msg, int may_drop)
+GST_clients_broadcast (const struct GNUNET_MessageHeader *msg,
+                       int may_drop)
 {
   struct TransportClient *tc;
 
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Asked to broadcast message of type %u with %u bytes\n",
+              (unsigned int) ntohs (msg->type),
+              (unsigned int) ntohs (msg->size));
   for (tc = clients_head; NULL != tc; tc = tc->next)
   {
-    if ((GNUNET_YES == may_drop) && (GNUNET_YES != tc->send_payload))
-      continue;                 /* skip, this client does not care about payload */
+    if ( (GNUNET_YES == may_drop) &&
+         (GNUNET_YES != tc->send_payload) )
+      continue; /* skip, this client does not care about payload */
     unicast (tc, msg, may_drop);
   }
 }
@@ -1395,7 +1653,8 @@ GST_clients_broadcast (const struct GNUNET_MessageHeader *msg, int may_drop)
  */
 void
 GST_clients_unicast (struct GNUNET_SERVER_Client *client,
-                     const struct GNUNET_MessageHeader *msg, int may_drop)
+                     const struct GNUNET_MessageHeader *msg,
+                     int may_drop)
 {
   struct TransportClient *tc;
 
@@ -1416,33 +1675,29 @@ GST_clients_unicast (struct GNUNET_SERVER_Client *client,
  */
 void
 GST_clients_broadcast_peer_notification (const struct GNUNET_PeerIdentity *peer,
-    const struct GNUNET_HELLO_Address *address,
-    enum GNUNET_TRANSPORT_PeerState state,
-    struct GNUNET_TIME_Absolute state_timeout)
+                                         const struct GNUNET_HELLO_Address *address,
+                                         enum GNUNET_TRANSPORT_PeerState state,
+                                         struct GNUNET_TIME_Absolute state_timeout)
 {
   struct PeerIterateResponseMessage *msg;
   struct MonitoringClient *mc;
-  static struct GNUNET_PeerIdentity all_zeros;
+
   msg = compose_address_iterate_response_message (peer, address);
   msg->state = htonl (state);
   msg->state_timeout = GNUNET_TIME_absolute_hton (state_timeout);
-  mc = peer_monitoring_clients_head;
-  while (mc != NULL)
-  {
+  for (mc = peer_monitoring_clients_head; NULL != mc; mc = mc->next)
     if ((0 == memcmp (&mc->peer, &all_zeros,
                       sizeof (struct GNUNET_PeerIdentity))) ||
         (0 == memcmp (&mc->peer, peer,
                       sizeof (struct GNUNET_PeerIdentity))))
-    {
-      GNUNET_SERVER_notification_context_unicast (peer_nc, mc->client,
-                                                  &msg->header, GNUNET_NO);
-    }
-
-    mc = mc->next;
-  }
+      GNUNET_SERVER_notification_context_unicast (peer_nc,
+                                                  mc->client,
+                                                  &msg->header,
+                                                  GNUNET_NO);
   GNUNET_free (msg);
 }
 
+
 /**
  * Broadcast the new validation changes to all clients monitoring the peer.
  *
@@ -1454,41 +1709,34 @@ GST_clients_broadcast_peer_notification (const struct GNUNET_PeerIdentity *peer,
  * @param state state of validation notification
  */
 void
-GST_clients_broadcast_validation_notification (
-    const struct GNUNET_PeerIdentity *peer,
-    const struct GNUNET_HELLO_Address *address,
-    struct GNUNET_TIME_Absolute last_validation,
-    struct GNUNET_TIME_Absolute valid_until,
-    struct GNUNET_TIME_Absolute next_validation,
-    enum GNUNET_TRANSPORT_ValidationState state)
+GST_clients_broadcast_validation_notification (const struct GNUNET_PeerIdentity *peer,
+                                               const struct GNUNET_HELLO_Address *address,
+                                               struct GNUNET_TIME_Absolute last_validation,
+                                               struct GNUNET_TIME_Absolute valid_until,
+                                               struct GNUNET_TIME_Absolute next_validation,
+                                               enum GNUNET_TRANSPORT_ValidationState state)
 {
   struct ValidationIterateResponseMessage *msg;
   struct MonitoringClient *mc;
-  static struct GNUNET_PeerIdentity all_zeros;
 
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-      "Sending information about for validation entry for peer `%s' using address `%s'\n",
-      GNUNET_i2s(peer), (address != NULL) ? GST_plugins_a2s (address) : "<none>");
-
+              "Sending information about for validation entry for peer `%s' using address `%s'\n",
+              GNUNET_i2s(peer),
+              (address != NULL) ? GST_plugins_a2s (address) : "<none>");
   msg = compose_validation_iterate_response_message (peer, address);
   msg->last_validation = GNUNET_TIME_absolute_hton(last_validation);
   msg->valid_until = GNUNET_TIME_absolute_hton(valid_until);
   msg->next_validation = GNUNET_TIME_absolute_hton(next_validation);
   msg->state = htonl ((uint32_t) state);
-  mc = val_monitoring_clients_head;
-  while (mc != NULL)
-  {
+  for (mc = val_monitoring_clients_head; NULL != mc; mc = mc->next)
     if ((0 == memcmp (&mc->peer, &all_zeros,
                       sizeof (struct GNUNET_PeerIdentity))) ||
         (0 == memcmp (&mc->peer, peer,
                       sizeof (struct GNUNET_PeerIdentity))))
-    {
-      GNUNET_SERVER_notification_context_unicast (val_nc, mc->client,
-                                                  &msg->header, GNUNET_NO);
-
-    }
-    mc = mc->next;
-  }
+      GNUNET_SERVER_notification_context_unicast (val_nc,
+                                                  mc->client,
+                                                  &msg->header,
+                                                  GNUNET_NO);
   GNUNET_free (msg);
 }