-doxygen
[oweals/gnunet.git] / src / transport / gnunet-service-transport_clients.c
index 7ce455f7d3174af5732f7d148273c0c80036b803..0aeb661d4662bff667d0760dc0a0b1761b58dfb1 100644 (file)
@@ -1,6 +1,6 @@
 /*
      This file is part of GNUnet.
-     (C) 2010,2011 Christian Grothoff (and other contributing authors)
+     (C) 2010-2013 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
 #include "gnunet-service-transport_neighbours.h"
 #include "gnunet-service-transport_plugins.h"
 #include "gnunet-service-transport_validation.h"
+#include "gnunet-service-transport_manipulation.h"
 #include "gnunet-service-transport.h"
 #include "transport.h"
 
+
 /**
  * How many messages can we have pending for a given client process
  * before we start to drop incoming messages?  We typically should
@@ -102,7 +104,7 @@ struct TransportClient
   /**
    * Current transmit request handle.
    */
-  struct GNUNET_CONNECTION_TransmitHandle *th;
+  struct GNUNET_SERVER_TransmitHandle *th;
 
   /**
    * Length of the list of messages pending for this client.
@@ -115,6 +117,55 @@ struct TransportClient
   int send_payload;
 };
 
+/**
+ * Context for address to string operations
+ */
+struct AddressToStringContext
+{
+  /**
+   * This is a doubly-linked list.
+   */
+  struct AddressToStringContext *next;
+
+  /**
+   * This is a doubly-linked list.
+   */
+  struct AddressToStringContext *prev;
+
+  /**
+   * Transmission context
+   */
+  struct GNUNET_SERVER_TransmitContext* tc;
+};
+
+/**
+ * Client monitoring changes of active addresses of our neighbours.
+ */
+struct MonitoringClient
+{
+  /**
+   * This is a doubly-linked list.
+   */
+  struct MonitoringClient *next;
+
+  /**
+   * This is a doubly-linked list.
+   */
+  struct MonitoringClient *prev;
+
+  /**
+   * Handle to the client.
+   */
+  struct GNUNET_SERVER_Client *client;
+
+  /**
+   * Peer identity to monitor the addresses of.
+   * Zero to monitor all neighrours.
+   */
+  struct GNUNET_PeerIdentity peer;
+
+};
+
 
 /**
  * Head of linked list of all clients to this service.
@@ -126,6 +177,33 @@ static struct TransportClient *clients_head;
  */
 static struct TransportClient *clients_tail;
 
+/**
+ * Head of linked list of all pending address iterations
+ */
+struct AddressToStringContext *a2s_head;
+
+/**
+ * Tail of linked list of all pending address iterations
+ */
+struct AddressToStringContext *a2s_tail;
+
+/**
+ * Head of linked list of monitoring clients.
+ */
+static struct MonitoringClient *monitoring_clients_head;
+
+/**
+ * Tail of linked list of monitoring clients.
+ */
+static struct MonitoringClient *monitoring_clients_tail;
+
+/**
+ * Notification context, to send updates on changes to active addresses
+ * of our neighbours.
+ */
+static struct GNUNET_SERVER_NotificationContext *nc;
+
+
 /**
  * Find the internal handle associated with the given client handle
  *
@@ -137,13 +215,9 @@ lookup_client (struct GNUNET_SERVER_Client *client)
 {
   struct TransportClient *tc;
 
-  tc = clients_head;
-  while (tc != NULL)
-  {
+  for (tc = clients_head; NULL != tc; tc = tc->next)
     if (tc->client == client)
       return tc;
-    tc = tc->next;
-  }
   return NULL;
 }
 
@@ -159,26 +233,80 @@ setup_client (struct GNUNET_SERVER_Client *client)
 {
   struct TransportClient *tc;
 
-  GNUNET_assert (lookup_client (client) == NULL);
-  tc = GNUNET_malloc (sizeof (struct TransportClient));
+  GNUNET_assert (NULL == lookup_client (client));
+  tc = GNUNET_new (struct TransportClient);
   tc->client = client;
-
-#if DEBUG_TRANSPORT
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Client %X connected\n", tc);
-#endif
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Client %p connected\n",
+              tc);
   return tc;
 }
 
 
+/**
+ * Find the handle to the monitoring client associated with the given
+ * client handle
+ *
+ * @param client server's client handle to look up
+ * @return handle to the monitoring client
+ */
+static struct MonitoringClient *
+lookup_monitoring_client (struct GNUNET_SERVER_Client *client)
+{
+  struct MonitoringClient *mc;
+
+  for (mc = monitoring_clients_head; NULL != mc; mc = mc->next)
+    if (mc->client == client)
+      return mc;
+  return NULL;
+}
+
+
+/**
+ * Setup a new monitoring client using the given server client handle and
+ * the peer identity.
+ *
+ * @param client server's client handle to create our internal handle for
+ * @param peer identity of the peer to monitor the addresses of,
+ *             zero to monitor all neighrours.
+ * @return handle to the new monitoring client
+ */
+static struct MonitoringClient *
+setup_monitoring_client (struct GNUNET_SERVER_Client *client,
+                         struct GNUNET_PeerIdentity *peer)
+{
+  struct MonitoringClient *mc;
+  static struct GNUNET_PeerIdentity all_zeros;
+
+  GNUNET_assert (lookup_monitoring_client (client) == NULL);
+  mc = GNUNET_new (struct MonitoringClient);
+  mc->client = client;
+  mc->peer = *peer;
+  GNUNET_CONTAINER_DLL_insert (monitoring_clients_head,
+                               monitoring_clients_tail,
+                               mc);
+  GNUNET_SERVER_notification_context_add (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));
+  else
+    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
  * was closed for writing in the meantime.
  *
  * @param cls closure
- * @param size number of bytes available in buf
+ * @param size number of bytes available in @a buf
  * @param buf where the callee should write the message
- * @return number of bytes written to buf
+ * @return number of bytes written to @a buf
  */
 static size_t
 transmit_to_client_callback (void *cls, size_t size, void *buf)
@@ -191,12 +319,10 @@ transmit_to_client_callback (void *cls, size_t size, void *buf)
   size_t tsize;
 
   tc->th = NULL;
-  if (buf == NULL)
+  if (NULL == buf)
   {
-#if DEBUG_TRANSPORT
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                 "Transmission to client failed, closing connection.\n");
-#endif
     return 0;
   }
   cbuf = buf;
@@ -207,12 +333,11 @@ transmit_to_client_callback (void *cls, size_t size, void *buf)
     msize = ntohs (msg->size);
     if (msize + tsize > size)
       break;
-#if DEBUG_TRANSPORT
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-                "Transmitting message of type %u to client %X.\n",
+                "Transmitting message of type %u to client %p.\n",
                 ntohs (msg->type), tc);
-#endif
-    GNUNET_CONTAINER_DLL_remove (tc->message_queue_head, tc->message_queue_tail,
+    GNUNET_CONTAINER_DLL_remove (tc->message_queue_head,
+                                 tc->message_queue_tail,
                                  q);
     tc->message_count--;
     memcpy (&cbuf[tsize], msg, msize);
@@ -226,7 +351,7 @@ transmit_to_client_callback (void *cls, size_t size, void *buf)
         GNUNET_SERVER_notify_transmit_ready (tc->client, msize,
                                              GNUNET_TIME_UNIT_FOREVER_REL,
                                              &transmit_to_client_callback, tc);
-    GNUNET_assert (tc->th != NULL);
+    GNUNET_assert (NULL != tc->th);
   }
   return tsize;
 }
@@ -237,21 +362,29 @@ transmit_to_client_callback (void *cls, size_t size, void *buf)
  *
  * @param tc target of the message
  * @param msg message to transmit
- * @param may_drop GNUNET_YES if the message can be dropped
+ * @param may_drop #GNUNET_YES if the message can be dropped
  */
 static void
-unicast (struct TransportClient *tc, const struct GNUNET_MessageHeader *msg,
+unicast (struct TransportClient *tc,
+         const struct GNUNET_MessageHeader *msg,
          int may_drop)
 {
   struct ClientMessageQueueEntry *q;
   uint16_t msize;
 
+  if (NULL == msg)
+  {
+    GNUNET_break (0);
+    return;
+  }
+
   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"),
-                ntohs (msg->type), ntohs (msg->size), tc->message_count,
+                _("Dropping message of type %u and size %u, have %u/%u messages pending\n"),
+                ntohs (msg->type),
+                ntohs (msg->size),
+                tc->message_count,
                 MAX_PENDING);
     GNUNET_STATISTICS_update (GST_stats,
                               gettext_noop
@@ -266,13 +399,13 @@ unicast (struct TransportClient *tc, const struct GNUNET_MessageHeader *msg,
   GNUNET_CONTAINER_DLL_insert_tail (tc->message_queue_head,
                                     tc->message_queue_tail, q);
   tc->message_count++;
-  if (tc->th != NULL)
+  if (NULL != tc->th)
     return;
   tc->th =
       GNUNET_SERVER_notify_transmit_ready (tc->client, msize,
                                            GNUNET_TIME_UNIT_FOREVER_REL,
                                            &transmit_to_client_callback, tc);
-  GNUNET_assert (tc->th != NULL);
+  GNUNET_assert (NULL != tc->th);
 }
 
 
@@ -287,17 +420,24 @@ static void
 client_disconnect_notification (void *cls, struct GNUNET_SERVER_Client *client)
 {
   struct TransportClient *tc;
+  struct MonitoringClient *mc;
   struct ClientMessageQueueEntry *mqe;
 
   if (client == NULL)
     return;
+  mc = lookup_monitoring_client (client);
+  if (mc != NULL)
+  {
+    GNUNET_CONTAINER_DLL_remove (monitoring_clients_head,
+                                 monitoring_clients_tail,
+                                 mc);
+    GNUNET_free (mc);
+  }
   tc = lookup_client (client);
   if (tc == NULL)
     return;
-#if DEBUG_TRANSPORT
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG | GNUNET_ERROR_TYPE_BULK,
-              "Client %X disconnected, cleaning up.\n", tc);
-#endif
+              "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,
@@ -308,7 +448,7 @@ client_disconnect_notification (void *cls, struct GNUNET_SERVER_Client *client)
   GNUNET_CONTAINER_DLL_remove (clients_head, clients_tail, tc);
   if (tc->th != NULL)
   {
-    GNUNET_CONNECTION_notify_transmit_ready_cancel (tc->th);
+    GNUNET_SERVER_notify_transmit_ready_cancel (tc->th);
     tc->th = NULL;
   }
   GNUNET_break (0 == tc->message_count);
@@ -320,35 +460,31 @@ client_disconnect_notification (void *cls, struct GNUNET_SERVER_Client *client)
  * Function called for each of our connected neighbours.  Notify the
  * client about the existing neighbour.
  *
- * @param cls the 'struct TransportClient' to notify
+ * @param cls the `struct TransportClient *` to notify
  * @param peer identity of the neighbour
- * @param ats performance data
- * @param ats_count number of entries in ats (excluding 0-termination)
  * @param address the address
+ * @param bandwidth_in inbound bandwidth in NBO
+ * @param bandwidth_out outbound bandwidth in NBO
  */
 static void
 notify_client_about_neighbour (void *cls,
                                const struct GNUNET_PeerIdentity *peer,
-                               const struct GNUNET_ATS_Information *ats,
-                               uint32_t ats_count,
-                               const struct GNUNET_HELLO_Address *address)
+                               const struct GNUNET_HELLO_Address *address,
+                               struct GNUNET_BANDWIDTH_Value32NBO bandwidth_in,
+                               struct GNUNET_BANDWIDTH_Value32NBO bandwidth_out)
 {
   struct TransportClient *tc = cls;
   struct ConnectInfoMessage *cim;
-  struct GNUNET_ATS_Information *ap;
-  size_t size =
-      sizeof (struct ConnectInfoMessage) +
-      ats_count * sizeof (struct GNUNET_ATS_Information);
-  char buf[size];
+  size_t size = sizeof (struct ConnectInfoMessage);
+  char buf[size] GNUNET_ALIGN;
 
   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->ats_count = htonl (ats_count);
   cim->id = *peer;
-  ap = (struct GNUNET_ATS_Information *) &cim[1];
-  memcpy (ap, ats, ats_count * sizeof (struct GNUNET_ATS_Information));
+  cim->quota_in = bandwidth_in;
+  cim->quota_out = bandwidth_out;
   unicast (tc, &cim->header, GNUNET_NO);
 }
 
@@ -372,22 +508,14 @@ clients_handle_start (void *cls, struct GNUNET_SERVER_Client *client,
 
   tc = lookup_client (client);
 
-#if DEBUG_TRANSPORT
-  if (tc != NULL)
-    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG | GNUNET_ERROR_TYPE_BULK,
-                "Client %X sent START\n", tc);
-  else
-    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG | GNUNET_ERROR_TYPE_BULK,
-                "Client %X sent START\n", tc);
-#endif
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG | GNUNET_ERROR_TYPE_BULK,
+              "Client %p sent START\n", tc);
   if (tc != NULL)
   {
     /* got 'start' twice from the same client, not allowed */
-#if DEBUG_TRANSPORT
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG | GNUNET_ERROR_TYPE_BULK,
-                "TransportClient %X ServerClient %X  sent multiple START messages\n",
+                "TransportClient %p ServerClient %p sent multiple START messages\n",
                 tc, tc->client);
-#endif
     GNUNET_break (0);
     GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
     return;
@@ -454,16 +582,25 @@ struct SendTransmitContinuationContext
  * OK to send the next message.
  *
  * @param cls closure
- * @param success GNUNET_OK on success, GNUNET_NO on failure, GNUNET_SYSERR if we're not connected
+ * @param success #GNUNET_OK on success, #GNUNET_NO on failure, #GNUNET_SYSERR if we're not connected
+ * @param bytes_payload bytes payload sent
+ * @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);
@@ -482,7 +619,8 @@ handle_send_transmit_continuation (void *cls, int success)
  * @param message the send message that was sent
  */
 static void
-clients_handle_send (void *cls, struct GNUNET_SERVER_Client *client,
+clients_handle_send (void *cls,
+                     struct GNUNET_SERVER_Client *client,
                      const struct GNUNET_MessageHeader *message)
 {
   const struct OutboundMessage *obm;
@@ -518,23 +656,19 @@ clients_handle_send (void *cls, struct GNUNET_SERVER_Client *client,
     GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
     return;
   }
-  GNUNET_STATISTICS_update (GST_stats,
-                            gettext_noop
-                            ("# bytes payload received for other peers"), msize,
-                            GNUNET_NO);
-#if DEBUG_TRANSPORT
+
   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);
-#endif
+              "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 */
-#if DEBUG_TRANSPORT
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                 "Could not send message to peer `%s': not connected\n",
                 GNUNET_i2s (&obm->peer));
-#endif
     GNUNET_STATISTICS_update (GST_stats,
                               gettext_noop
                               ("# bytes payload dropped (other peer was not connected)"),
@@ -547,7 +681,7 @@ clients_handle_send (void *cls, struct GNUNET_SERVER_Client *client,
   stcc->target = obm->peer;
   stcc->client = client;
   GNUNET_SERVER_client_keep (client);
-  GST_neighbours_send (&obm->peer, obmm, msize,
+  GST_manipulation_send (&obm->peer, obmm, msize,
                        GNUNET_TIME_relative_ntoh (obm->timeout),
                        &handle_send_transmit_continuation, stcc);
 }
@@ -559,15 +693,21 @@ clients_handle_send (void *cls, struct GNUNET_SERVER_Client *client,
  *
  * @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 result #GNUNET_OK if the connection is allowed,
+ *               #GNUNET_NO if not
  */
 static void
-try_connect_if_allowed (void *cls, const struct GNUNET_PeerIdentity *peer,
+try_connect_if_allowed (void *cls,
+                        const struct GNUNET_PeerIdentity *peer,
                         int result)
 {
   if (GNUNET_OK != result)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Blacklist refuses connection attempt to peer `%s'\n",
+                GNUNET_i2s (peer));
     return;                     /* not allowed */
+  }
   GST_neighbours_try_connect (peer);
 }
 
@@ -590,13 +730,24 @@ clients_handle_request_connect (void *cls, struct GNUNET_SERVER_Client *client,
                             gettext_noop
                             ("# REQUEST CONNECT messages received"), 1,
                             GNUNET_NO);
-#if DEBUG_TRANSPORT
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              "Received a request connect message for peer `%s'\n",
-              GNUNET_i2s (&trcm->peer));
-#endif
-  (void) GST_blacklist_test_allowed (&trcm->peer, NULL, &try_connect_if_allowed,
+
+  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_DEBUG,
+                "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);
+  }
   GNUNET_SERVER_receive_done (client, GNUNET_OK);
 }
 
@@ -611,16 +762,17 @@ clients_handle_request_connect (void *cls, struct GNUNET_SERVER_Client *client,
 static void
 transmit_address_to_client (void *cls, const char *buf)
 {
-  struct GNUNET_SERVER_TransmitContext *tc = cls;
-
+  struct AddressToStringContext *actx = cls;
   if (NULL == buf)
   {
-    GNUNET_SERVER_transmit_context_append_data (tc, NULL, 0,
+    GNUNET_SERVER_transmit_context_append_data (actx->tc, NULL, 0,
                                                 GNUNET_MESSAGE_TYPE_TRANSPORT_ADDRESS_TO_STRING_REPLY);
-    GNUNET_SERVER_transmit_context_run (tc, GNUNET_TIME_UNIT_FOREVER_REL);
+    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;
   }
-  GNUNET_SERVER_transmit_context_append_data (tc, buf, strlen (buf) + 1,
+  GNUNET_SERVER_transmit_context_append_data (actx->tc, buf, strlen (buf) + 1,
                                               GNUNET_MESSAGE_TYPE_TRANSPORT_ADDRESS_TO_STRING_REPLY);
 }
 
@@ -644,6 +796,7 @@ clients_handle_address_to_string (void *cls,
   uint32_t address_len;
   uint16_t size;
   struct GNUNET_SERVER_TransmitContext *tc;
+  struct AddressToStringContext *actx;
   struct GNUNET_TIME_Relative rtimeout;
   int32_t numeric;
 
@@ -664,8 +817,7 @@ clients_handle_address_to_string (void *cls,
   }
   address = (const char *) &alum[1];
   plugin_name = (const char *) &address[address_len];
-  if (plugin_name[size - sizeof (struct AddressLookupMessage) - address_len - 1]
-      != '\0')
+  if ('\0' != plugin_name[size - sizeof (struct AddressLookupMessage) - address_len - 1])
   {
     GNUNET_break (0);
     GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
@@ -674,7 +826,7 @@ clients_handle_address_to_string (void *cls,
   rtimeout = GNUNET_TIME_relative_ntoh (alum->timeout);
   numeric = ntohs (alum->numeric_only);
   tc = GNUNET_SERVER_transmit_context_create (client);
-  papi = GST_plugins_find (plugin_name);
+  papi = GST_plugins_printer_find (plugin_name);
   if (NULL == papi)
   {
     GNUNET_SERVER_transmit_context_append_data (tc, NULL, 0,
@@ -682,57 +834,81 @@ clients_handle_address_to_string (void *cls,
     GNUNET_SERVER_transmit_context_run (tc, rtimeout);
     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,
-                                tc);
+                                actx);
 }
 
 
 /**
- * Output the active address of connected neighbours to the given client.
+ * Compose AddressIterateResponseMessage using the given peer and address.
  *
- * @param cls the 'struct GNUNET_SERVER_TransmitContext' for transmission to the client
- * @param peer identity of the neighbour
- * @param ats performance data
- * @param ats_count number of entries in ats (excluding 0-termination)
- * @param address the address
+ * @param peer identity of the peer
+ * @param address the address, NULL on disconnect
+ * @return composed message
  */
-static void
-output_address (void *cls, const struct GNUNET_PeerIdentity *peer,
-                const struct GNUNET_ATS_Information *ats, uint32_t ats_count,
-                const struct GNUNET_HELLO_Address *address)
+static struct AddressIterateResponseMessage *
+compose_address_iterate_response_message (const struct GNUNET_PeerIdentity *peer,
+                                          const struct GNUNET_HELLO_Address *address)
 {
-  struct GNUNET_SERVER_TransmitContext *tc = cls;
   struct AddressIterateResponseMessage *msg;
   size_t size;
   size_t tlen;
   size_t alen;
   char *addr;
 
-  tlen = strlen (address->transport_name) + 1;
-  alen = address->address_length;
+  GNUNET_assert (NULL != peer);
+  if (NULL != address)
+  {
+    tlen = strlen (address->transport_name) + 1;
+    alen = address->address_length;
+  }
+  else
+    tlen = alen = 0;
   size = (sizeof (struct AddressIterateResponseMessage) + alen + tlen);
+  msg = GNUNET_malloc (size);
+  msg->header.size = htons (size);
+  msg->header.type =
+      htons (GNUNET_MESSAGE_TYPE_TRANSPORT_ADDRESS_ITERATE_RESPONSE);
+  msg->reserved = htonl (0);
+  msg->peer = *peer;
+  msg->addrlen = htonl (alen);
+  msg->pluginlen = htonl (tlen);
+  if (NULL != address)
   {
-    char buf[size];
-
-    msg = (struct AddressIterateResponseMessage *) buf;
-    msg->reserved = htonl (0);
-    msg->peer = *peer;
-    msg->addrlen = htonl (alen);
-    msg->pluginlen = htonl (tlen);
     addr = (char *) &msg[1];
     memcpy (addr, address->address, alen);
     memcpy (&addr[alen], address->transport_name, tlen);
-    GNUNET_SERVER_transmit_context_append_data (tc,
-                                                &buf[sizeof
-                                                     (struct
-                                                      GNUNET_MessageHeader)],
-                                                size -
-                                                sizeof (struct
-                                                        GNUNET_MessageHeader),
-                                                GNUNET_MESSAGE_TYPE_TRANSPORT_ADDRESS_ITERATE_RESPONSE);
   }
+  return msg;
+}
+
+
+/**
+ * Output the active address of connected neighbours to the given client.
+ *
+ * @param cls the 'struct GNUNET_SERVER_TransmitContext' for transmission to the client
+ * @param peer identity of the neighbour
+ * @param address the address
+ * @param bandwidth_in inbound quota in NBO
+ * @param bandwidth_out outbound quota in NBO
+ */
+static void
+output_address (void *cls, const struct GNUNET_PeerIdentity *peer,
+                const struct GNUNET_HELLO_Address *address,
+                struct GNUNET_BANDWIDTH_Value32NBO bandwidth_in,
+                struct GNUNET_BANDWIDTH_Value32NBO bandwidth_out)
+{
+  struct GNUNET_SERVER_TransmitContext *tc = cls;
+  struct AddressIterateResponseMessage *msg;
+
+  msg = compose_address_iterate_response_message (peer, address);
+  GNUNET_SERVER_transmit_context_append_message (tc, &msg->header);
+  GNUNET_free (msg);
 }
 
 
@@ -767,10 +943,13 @@ clients_handle_address_iterate (void *cls, struct GNUNET_SERVER_Client *client,
     return;
   }
   msg = (struct AddressIterateMessage *) message;
-  if (GNUNET_YES != ntohl (msg->one_shot))
+  if ( (GNUNET_YES != ntohl (msg->one_shot)) &&
+       (NULL != lookup_monitoring_client (client)) )
   {
-    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
-                "Address monitoring not implemented\n");
+    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;
   }
@@ -786,10 +965,15 @@ clients_handle_address_iterate (void *cls, struct GNUNET_SERVER_Client *client,
     /* just return one neighbour */
     address = GST_neighbour_get_current_address (&msg->peer);
     if (address != NULL)
-      output_address (tc, &msg->peer, NULL, 0, address);
+      output_address (tc, &msg->peer, address,
+                      GNUNET_CONSTANTS_DEFAULT_BW_IN_OUT,
+                      GNUNET_CONSTANTS_DEFAULT_BW_IN_OUT);
   }
-  GNUNET_SERVER_transmit_context_append_data (tc, NULL, 0,
-                                              GNUNET_MESSAGE_TYPE_TRANSPORT_ADDRESS_ITERATE_RESPONSE);
+  if (GNUNET_YES != ntohl (msg->one_shot))
+    setup_monitoring_client (client, &msg->peer);
+  else
+    GNUNET_SERVER_transmit_context_append_data (tc, NULL, 0,
+                                               GNUNET_MESSAGE_TYPE_TRANSPORT_ADDRESS_ITERATE_RESPONSE);
   GNUNET_SERVER_transmit_context_run (tc, GNUNET_TIME_UNIT_FOREVER_REL);
 }
 
@@ -823,8 +1007,11 @@ GST_clients_start (struct GNUNET_SERVER_Handle *server)
     {&GST_blacklist_handle_reply, NULL,
      GNUNET_MESSAGE_TYPE_TRANSPORT_BLACKLIST_REPLY,
      sizeof (struct BlacklistMessage)},
+    {&GST_manipulation_set_metric, NULL,
+     GNUNET_MESSAGE_TYPE_TRANSPORT_TRAFFIC_METRIC, 0},
     {NULL, NULL, 0, 0}
   };
+  nc = GNUNET_SERVER_notification_context_create (server, 0);
   GNUNET_SERVER_add_handlers (server, handlers);
   GNUNET_SERVER_disconnect_notify (server, &client_disconnect_notification,
                                    NULL);
@@ -837,7 +1024,19 @@ GST_clients_start (struct GNUNET_SERVER_Handle *server)
 void
 GST_clients_stop ()
 {
-  /* nothing to do */
+  struct AddressToStringContext *cur;
+
+  while (NULL != (cur = a2s_head))
+  {
+    GNUNET_SERVER_transmit_context_destroy (cur->tc, GNUNET_NO);
+    GNUNET_CONTAINER_DLL_remove (a2s_head, a2s_tail, cur);
+    GNUNET_free (cur);
+  }
+  if (NULL != nc)
+  {
+    GNUNET_SERVER_notification_context_destroy (nc);
+    nc = NULL;
+  }
 }
 
 
@@ -845,14 +1044,14 @@ GST_clients_stop ()
  * Broadcast the given message to all of our clients.
  *
  * @param msg message to broadcast
- * @param may_drop GNUNET_YES if the message can be dropped / is payload
+ * @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)
 {
   struct TransportClient *tc;
 
-  for (tc = clients_head; tc != NULL; tc = tc->next)
+  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 */
@@ -866,7 +1065,7 @@ GST_clients_broadcast (const struct GNUNET_MessageHeader *msg, int may_drop)
  *
  * @param client target of the message
  * @param msg message to transmit
- * @param may_drop GNUNET_YES if the message can be dropped
+ * @param may_drop #GNUNET_YES if the message can be dropped
  */
 void
 GST_clients_unicast (struct GNUNET_SERVER_Client *client,
@@ -881,4 +1080,36 @@ GST_clients_unicast (struct GNUNET_SERVER_Client *client,
 }
 
 
+/**
+ * Broadcast the new active address to all clients monitoring the peer.
+ *
+ * @param peer peer this update is about (never NULL)
+ * @param address address, NULL on disconnect
+ */
+void
+GST_clients_broadcast_address_notification (const struct GNUNET_PeerIdentity *peer,
+                                            const struct GNUNET_HELLO_Address *address)
+{
+  struct AddressIterateResponseMessage *msg;
+  struct MonitoringClient *mc;
+  static struct GNUNET_PeerIdentity all_zeros;
+  msg = compose_address_iterate_response_message (peer, address);
+  mc = monitoring_clients_head;
+  while (mc != NULL)
+  {
+    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 (nc, mc->client,
+                                                  &msg->header, GNUNET_NO);
+    }
+
+    mc = mc->next;
+  }
+  GNUNET_free (msg);
+}
+
+
 /* end of file gnunet-service-transport_clients.c */